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This book will present to the reader the evolution of refinery processes during the last century, and will also discuss the means by which refinery processes will evolve during the next three to five decades.
The Reﬁnery of the FutureJames G. SpeightAMSTERDAM • BOSTON • HEIDELBERG • LONDONNEW YORK • OXFORD • PARIS • SAN DIEGOSAN FRANCISCO • SINGAPORE • SYDNEY • TOKYOGulf Professional Publishing is an imprint of Elsevier read more..
Gulf Professional Publishing is an imprint of ElsevierThe Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, UK30 Corporate Drive, Suite 400, Burlington, MA 01803, USAFirst edition 2011CopyrightÓ 2011 Elsevier Inc. All rights reservedNo part of this publication may be reproduced, stored in a retrieval system or transmitted inany form or by any means electronic, mechanical, photocopying, recording or otherwisewithout the prior written permission of the publisherPermissions may be sought read more..
PrefaceThe petroleum reﬁning industry integrates many process operations that are engagedin reﬁning crude petroleum into petroleum products, liquid fuels such as gasoline anddiesel in particular. It also incorporates many processes that produce raw materials forthe petrochemical industry.Over the past four decades, the reﬁning industry has experienced signiﬁcantchanges in oil market dynamics, resource availability, and technological advance-ments. Advancements made in exploration, read more..
process, to development and use of more innovative processes that will maximize theyields of liquid fuels, or other desired products, from the feedstock.The need to upgrade processes continues, in order to fulﬁll market demand, as wellas to satisfy environmental regulations. The need for residuum conversion tech-nology, has emerged as result of a declining market for residual fuel oil and thenecessity to upgrade crude oil residua beyond the capabilities of the visbreaking,coking and read more..
However, the reﬁnery of the future will be more technologically focused than thereﬁnery of today – a trend that has already commenced. It will make only high-valueproducts, with one of those products being power. The reﬁnery will be a cleanreﬁnery, with a high-value, energy-efﬁcient installation to make it environmentallybenign and its carbon footprint negligible. The reﬁnery will also be a smart reﬁnery,insofar as it will be able to accept a variety of feedstocks, including read more..
1 Feedstocks1.1 Introduction1.1.1A Brief History of Petroleum ExtractionThe modern petroleum industry began in the 1850s with the discovery of petroleumin 1857, and its subsequent commercialization in Pennsylvania in 1859 (Bell, 1945;Yergin, 1991; Bower, 2009). The modern reﬁning era is said to have commenced in1862 with the ﬁrst appearance of petroleum distillation. The story of the discovery ofthe character of petroleum is somewhat circuitous but worthy of mention (Burke,1996).Joseph read more..
In 1809 he set up in business with an apothecary named Darling, assembledapparatus to impregnate ﬁfty bottles of water a day and opened two soda-waterfountains in New York City; one at the Tontine Coffee House and one at the CityHotel. The decor was hugely expensive, and they only sold seventy glasses onopening day, but Darling was still optimistic. A friend of Priestley’s visited anddeclared that drinking the waters would prevent yellow fever. In spite of Silliman’shopes that the business read more..
At the outbreak of World War I in 1914, the two major producers of oil were theUnited States and Russia, but supplies were also being obtained from Indonesia,Rumania, and Mexico. During the 1920s and 1930s, attention was also focused onother areas for oil production, such as other parts of the United States and the MiddleEast. At this time European and African countries were not considered major oil-producing areas. In the post-1945 era, Middle Eastern countries continued to rise inimportance read more..
Heavy oils have a much higher viscosity and lower API gravity than conventionalpetroleum; and recovery of these petroleum types usually requires thermal stimulationof the reservoir. The generic term heavy oil is often applied to a crude oil that has lessthan 20 API and usually has a sulfur content that is higher than 2% by weight (Speight,2000). Heavy oils are also darker in color and may even be black.The term heavy oil has been used to describe both the heavy oils that requirethermal read more..
usually occur in the more viscous crude oils in amounts up to several thousand parts permillion. This can have serious consequences during processing of these feedstocks(Gruse and Stevens, 1960; Speight, 1984). Petroleum is a mixture of widely varyingconstituents and proportions, its physical properties and color may also vary widely.In the crude state petroleum has minimal value, but when reﬁned it provides high-value liquid fuels, solvents, lubricants, and many other products (Purdy, 1957). read more..
1.2.2.aProperties and Characteristics of Naphthenic AcidsIn the original deﬁnition, a naphthenic acid has a monobasic carboxyl group attachedto a saturated cycloaliphatic structure; but in the oil industry all organic acids in crudeoil are conventionally called naphthenic acids.Naphthenic acids can be very water-soluble and/or oil-soluble depending on theirmolecular weight, process temperatures, salinity of waters, and ﬂuid pressures. In theaqueous phase, naphthenic acids can exist in stable read more..
The attack also is described as lacking corrosion products. Damage is in the form ofunexpectedly high corrosion rates on alloys that would normally be expected to resistsulﬁdic corrosion (particularly steels with more than 9% Cr). In some cases, even veryhighly alloyed materials (i.e., 12% Cr, type 316 stainless steel (SS), type 317 SS, andin severe cases even 6% Mo stainless steel) have been found to exhibit sensitivity tocorrosion under these conditions.The corrosion reaction processes read more..
Potentiometric titration:In this method (ASTM D664), the sample is normally dissolved in toluene, propanol,and a little water. It is then titrated with alcoholic potassium hydroxide (if the sampleis acidic). Glass and reference electrodes are immersed in the sample and connectedto a voltmeter/potentiometer. The meter reading, which is measured in millivolts, isplotted against the volume of titrant. The end point is taken at the distinct inﬂection ofthe resulting titration curve corresponding read more..
However, more recent research has begun to highlight deﬁciencies in this method forsuch a direct correlation, and the total acid number is no longer considered to bea reliable indicator (Rikka, 2007).Furthermore, ASTM D947 is an older method and used for distillates, whilstASTM D664 is more accurate, but measures acid gases and hydrolyzable salts inaddition to organic acids. These differences are important for crude oils but lesssigniﬁcant in distillates and the Nalco NAT testing is more read more..
As more of these crude oils are blended with standard crude slates, the classicopportunity crude deﬁnition will broaden.The economics of purchasing opportunity crudes is so attractive that more andmore reﬁneries are updating their strategy for processing them. The experience gainedfrom treating over 50 high acid crude units over the last 20 years is used to manage therisks of processing new opportunity crudes as they appear on the market. Developinga successful strategy involves considering read more..
example, Cold Lake heavy crude oil has an API gravity equal to 12. Extra heavy oils,such as tar sand bitumen, usually have an API gravity in the range 5 to 10 (Athabascabitumen¼ 8 API). Residua would vary depending upon the temperature at whichdistillation was terminated but usually vacuum residua are in the range 2 to 8 API(Speight, 2000 and references cited therein; Speight and Ozum, 2002, and referencescited therein).Thus, the generic term heavy oil is often applied inconsistently to read more..
1994). In the simplest sense, pitch is the distillation residue of various types of tar.Thus, alternative names, such as bituminous sand or oil sand, are more appropriate,with the former being more technically correct. The term oil sand is used synony-mously with tar sand, and these terms are used interchangeably throughout this text.No single physical parameter, such as viscosity, is sufﬁcient to differentiatebitumen, heavy oil, and conventional petroleum. Properties such as API read more..
extent of these reserves in terms of the barrel unit. Indeed, investigations into theextent of many of the world’s deposits are continuing at such a rate that the numberschange considerably from one year to the next. Accordingly, the data quoted must berecognized as approximate. As technology changes so rapidly in this ﬁeld; it ispossible that this data may be out dated by the time this book goes to press.1.2.6BiomassBiomass is carbon based, and is composed of a mixture of organic compounds; read more..
Pimary biomass feedstocks that are currently being used for bioenergy includegrains and oilseed crops used for transportation fuel production, crop residues, suchas orchard trimmings and nut hulls and some residues from logging and forestoperations that are currently used for heat and power production. In the future it isanticipated that a larger proportion of the residues inherently generated from foodcrop harvesting, as well as a larger proportion of the residues generated fromongoing logging read more..
biomass feedstocks destined for combustion fall in the range 6,450 to 8,200 Btu/lb.For most agricultural residues, the heating values are even more uniform – approx-imately 6,450 to 7,300 Btu/lb, with the values for most woody materials being 7,750–8,200 Btu/lb. Moisture content is probably the most important determinant of theheating value. Air-dried biomass typically contains about 15–20% moisture, whereasthe moisture content for oven-dried biomass is around 0%. The bulk density, read more..
1.3 Occurrence and Reserves1.3.1Origins of PetroleumPetroleum has been used as an energy resource for more than 6,000 years and it is byfar the most common source of energy, particularly of liquid fuel. Use of petroleum isprojected to continue at current levels for at least two decades (BP, 2010)Fossil fuels namely coal, petroleum (including heavy oil and bitumen), natural gas,and oil shale that are produced by the decay of plant remains over geological time(Speight, 1990, 2008). Resources such read more..
gradient varies from place to place, it is generally on the order of 25 to 30C/km (15F/1000 ft or 120C/1000 ft, i.e. 0.015C per foot of depth or 0.012C per foot of depth).Petroleum is derived from aquatic plants and animals that lived and died hundredsof millions of years ago. Their remains mixed with mud and sand in layered depositsthat, over millennia, were geologically transformed into sedimentary rock. Gradually,the organic matter decomposed and eventually formed petroleum, or a read more..
Non-hydrocarbon constituents of petroleum include organic derivatives ofnitrogen, oxygen, sulfur, and the metals nickel and vanadium. Most of these impu-rities are removed during reﬁning.Geological techniques can determine only the existence of rock formations thatare favorable for oil deposits, not whether any oil is actually there. Drilling is theonly sure way to ascertain the presence of oil. With modern rotary equipment,wells can be drilled to depths of more than 30,000 feet (9,000 m). read more..
consumption fell by 2 million barrels per day, a fourth consecutive annualdecline. Consumption outside the OECD increased by 860,000 barrels per day.Consumption declined in North America, South and Central America and Europeand Eurasia, outweighing modest increases in the Middle East, Africa and Asia-Paciﬁc regions (BP, 2010).Global reﬁning capacity in 2009 grew by 2.2%, or 2 million barrels per day, thelargest increase since 1999,and non-OECD capacity surpassed OECD capacity for theﬁrst read more..
sulfur content (Swain, 1991, 1993, 1997, 2000). However, it is believed that therehas been a recent tendency for the quality of crude oil feedstocks to stabilize. Bethat as it may, reﬁneries have had to adapt to the changing nature of petroleumfeedstocks to produce the needed liquid fuels. Furthermore, the declining reservesof light crude oil have resulted in an increasing need to develop ways of upgradingthe abundant known heavy oil reserves. There is also considerable focus onadapting read more..
concentration of the resource, or the percent bitumen saturation, and its accessi-bility, usually measured by the overburden thickness. Recovery methods are basedeither on mining combined with some further processing, or operation on the oilsands in situ. Mining methods are applicable to shallow deposits, characterized bythe overburden ratio (i.e., overburden depth to thickness of tar sand deposit). Forexample, indications are that for the Athabasca deposit, no more than 15% of thein-place read more..
The numbers illustrating the amount of available biomass are, at best, estimatesand do not give any indications of the true, almost inexhaustible, amounts of materialavailable. However, the production of biomass and biofuels brings up the food cropsvs. fuel crops concept and there must be plans to ensure that local, regional, andnational food needs will be met before shifting crop acreage into bioenergy feed-stocks. This can place limitations on the amount of land available to produce read more..
Oxygen: 1.0Æ 0.2%Sulfur: 5.0Æ 0.5%Metals (Ni and V):>1000 ppmThe major exception to these narrow limits is the oxygen content, which can varyfrom 0.2% to 4.5%. This is not surprising, since oxygen is estimated by difference, sothe analysis is subject to the accumulation of all of the errors in the other elementaldata. In addition, bitumen is susceptible to aerial oxygen and the oxygen content isvery dependent upon the sample history.Furthermore, the ultimate composition of the Alberta read more..
components are still assumed to retain most of the essential characteristics of thehydrocarbons, but it is the non-hydrocarbon (sulfur, oxygen, nitrogen, and metal)constituents that play a large part in determining their processability (Rossiniet al., 1953; Lochte and Littmann, 1955; Schwartz and Brasseaux, 1958; Bran-denburg and Latham, 1968; Rall et al., 1972). The concentration of these non-hydrocarbon constituents (i.e., those organic compounds containing one or moresulfur, oxygen, or read more..
More generally, biomass feedstocks types are recognized by their speciﬁc chemicalcontent or the manner in which they are produced. However, the chemical compo-sition of biomass varies considerably.Predictably, the chemical and molecular composition of biomass impacts itssubsequent decomposition. The rate of decomposition is a primary facet of thedynamic process for converting biomass. It is dependent on biomass quality (chem-ical composition and molecular composition) as well as other factors, read more..
Every possible parafﬁn from methane (CH4) to n-decane (n-C10H22 – normaldecane) is present in the saturated components of petroleum gases and naphtha.Depending upon the source, low boiling parafﬁns may be the single most abundantcompound in a crude oil – reaching several percent. The iso-parafﬁns begin at C4 withiso-butane being the only possible non-linear isomer of butane. The number of possibleisomers grows rapidly with carbon number and there may be increased difﬁculty indealing read more..
and diesel fuel are all derived from raw middle distillate, which can also be obtainedfrom cracked and hydroprocessed reﬁnery streams.Within the saturated constituents, the concentration of n-parafﬁns decreasesregularly from C11 to C20. Two isoprenoid species (pristane¼ 2,6,10,14-tetrame-thylpentadecane and phytane¼ 2,6,10,14-tetramethylhexadecane) are generallypresent in crude oils in sufﬁcient concentrations to be seen as irregular peaksalongside the n-C17 and n-C18 peaks in a gas read more..
percentage rather than trace levels. Vacuum gas oil is occasionally used as a heatingoil, but is most commonly processed further; by catalytic cracking to producenaphtha, or by extraction to yield lubricating oil.Within the saturates in the vacuum gas oil fraction, the distribution of parafﬁns,iso-parafﬁns, and naphthenes is highly dependent upon the petroleum source.Generally, the naphthene constituents account for approximately two-thirds (60%) ofthe saturate constituents, but the overall read more..
in sterically-hindered structures, both hindered and unhindered structures havebeen found to be present at equivalent concentrations in the source rocks. Thisobservation has been rationalized as “geo-chromatography” in which the lesspolar (hindered) structures have moved more readily to the reservoir over time(Yammer, 1992).Oxygen levels in the vacuum gas oil parallel the nitrogen content. Thus, the mostcommonly identiﬁed oxygen compounds are the carboxylic acids and phenols,collectively read more..
The nickel and vanadium that are concentrated into the vacuum residuum appear tooccur as both porphyrin and non-porphyrin forms (Reynolds, 1998). The metal-loporphyrins can provide insights into petroleum maturation processes, they havebeen studied extensively and several families of related structures have been identi-ﬁed. On the other hand, the non-porphyrin metals remain less clearly identiﬁed,although some studies suggest that some still exist in a tetrapyrrole read more..
1.7 Petroleum ProductsPetroleum products and fuels, in contrast to petrochemicals, are those bulk fractionsthat are derived from petroleum and have commercial value as a bulk product(Speight, 2007).Petroleum fuels are also petroleum products and are the fuels by which industry isdriven. A brief mention of the properties of these fuels is useful here as it helps focuson the future needs and direction of the petroleum industry. More detailed descrip-tions are available elsewhere (Speight, 2007a read more..
Automotive gasoline typically contains approximately two hundred or morehydrocarbon compounds, whose relative concentrations vary considerably dependingon source, reﬁnery process, and product speciﬁcations. Typical hydrocarbon chainlengths range from C4 through Cl2 with a general hydrocarbon distribution consistingof alkanes (4–8%), alkenes (2–5%), iso-alkanes 25–40%, cycloalkanes (3–7%),cycloalkenes (l–4%), and aromatics (20–50%). However, these proportions varygreatly. Thermal read more..
made for speciﬁc uses and may be either distillates or residuals or mixtures of the two.The terms domestic fuel oil, diesel fuel oil, and heavy fuel oil are more indicative ofthe use of fuel oils.Diesel fuel oil is also a distillate fuel oil, and distils between 180 to 380C (356 to716F). Several grades are available depending on use: diesel oil for diesel comp-ression ignition (cars, trucks, and marine engines) and light heating oil for industrialand commercial uses.No. 1 fuel oil is a read more..
petroleum coke varies with the source of the crude oil, but in general, contains largeamounts of high molecular-weight, complex hydrocarbons (rich in carbon but corre-spondingly poor in hydrogen). The solubility of petroleum coke in carbon disulﬁde hasbeen reported to be as high as 50 to 80%, but this is in fact a misnomer, since the coke isthe insoluble, honeycomb material that is the end product of thermal processes.1.8 PetrochemicalsA petrochemical is any chemical derived from petroleum and read more..
Ancheyta, J., Speight, J.G., 2007. Heavy Oils and Residua. Hydroprocessing of Heavy Oilsand Residua. In: Jorge Ancheyta, Speight, James G. (Eds.). CRC-Taylor & FrancisGroup, Boca Raton, Florida 2007. Chapter 1.Andersen, S.I., 1994. Fuel Sci, Technol. International 12, 51.ASTM., 2009. Annual Book of Standards. American Society for Testing and Materials, WestConshohocken, Pennsylvania.Baugh, T.D., Grande, K.V., Mediaas, H., Vindstad, J.E., Wolf, N.O., 2005. The Discovery ofHigh Molecular read more..
Hood, R.I., Clerc, R.J., O’Neal, M.I., 1959. Journal of the Institute of Petroleum 45, 168.Jewell, D.M., Albaugh, E.W., Davis, B.E., Ruberto, R.G., 1974. Ind. Eng. Chem. Fund 13, 278.Johnson, P., 1997. Harper Collins Publishers Inc., New York, p. 602.Kane, R.D., Cayard, M.S., 2002. A Comprehensive Study on Naphthenic Acid Corrosion.Paper no. 02555. Corrosion 2002. NACE International, Houston, Texas.Kittrell, N. 2006. Removing Acid from Crude Oil. Crude Oil Quality Group. New OrleansMeeting. read more..
Speight. J.G. 1984. Characterization of Heavy Crude Oils and Petroleum Residues S. Kalia-guine and A. Mahay (Editors). Elsevier, Amsterdam. p. 515.Fuel Science and Technology Handbook. In: Speight, J.G. (Ed.). Marcel Dekker, New York.Speight, J.G., 1993. Gas Processing: Environmental Aspects and Methods. Butterworth-Heinemann, Oxford, England.Speight, J.G., 1994. The Chemistry and Technology of Coal, second ed. Marcel Dekker,New York.Speight, J.G. 1997. Kirk-Othmer Encyclopedia of Chemical read more..
2 Reﬁning Processes2.1Introduction2.1.1The Need to ReﬁnePetroleum in the crude state is of limited value, and reﬁning is required to produceproducts suitable for the market (Priestley, 1973). A reﬁnery is essentially a group ofmanufacturing plants that varies in number with the variety of products produced inorder to give a balanced operation.Petroleum products result from chemical processes that change the molecularnature of selected portions of crude oil; in other words, they are the read more..
during the 20th century. These innovations will need to continue as feedstocks changein character, until petroleum reﬁning as it is currently known becomes applied andadapted to other sources of energy (Speight, 2008).The petroleum reﬁnery of the twenty-ﬁrst century is a much more complexoperation than it was 100 to 120 years ago. Early reﬁneries were predominantlydistillation units, perhaps with ancillary units to remove objectionable odors from thevarious product streams. The reﬁnery read more..
produced blend stocks for high-octane aviation gasoline; and catalytic isomeriza-tion, which produced increased quantities of feedstocks for alkylation units, in orderto create high octane fuels from low-boiling hydrocarbons. Such processes redis-tributed hydrogen among the reﬁnery’s products via catalytic reforming of gasoline,catalytic hydrodesulfurization of distillates, and hydrocracking of midrangestreams. By the end of the 1940s, almost every reﬁning process was catalyticallybased; read more..
3.Environmental regulations that include more stringent regulations in relation to sulfur ingasoline and diesel.4.Technological development of new catalysts and processes.Petroleum reﬁneries were originally designed and operated over a narrow range ofcrude oil feedstocks, and produced a relatively ﬁxed slate of petroleum products.Since the 1970s, however, reﬁners have had to increase their ﬂexibility in order toadapt to a more volatile environment. Several possible paths may now be used read more..
A modern reﬁnery is a highly complex and integrated system for separating andtransforming crude oil into a wide variety of products. This includes transportationfuels, residual fuel oils, lubricants, and many other products. The simplest reﬁneryconﬁguration is the topping reﬁnery (Figure 2.2), which is designed to preparefeedstocks for petrochemical manufacture or for production of industrial fuels inremote oil-production areas.The topping reﬁnery consists of tankage, a distillation read more..
Crude LPG Light naphtha Heavy naphtha KeroseneGasoil Atmospheric residue Straight run fuel oil Diesel / gasoil Jet/Kero Gasoline Naphtha LPG CRUDE- DISTILLATION Figure 2.2A Topping Reﬁnery.Crude LPG Light naphtha Heavy REFORMER Reformate Hydrogen naphtha KeroseneGasoil Atmospheric residue Heavy fuel oil Diesel / gasoil Jet/Kero Gasoline Naphtha LPG CRUDE- DISTILLATION HYDRO- TREATER Figure 2.3A Hydroskimming Reﬁnery.44The Reﬁnery of the Future read more..
Crude LPG Light naphtha Isomerate ISOMERI- SATION Alkylate ALKY- LATION Heavy REFORMER Reformate H2 naphtha KeroseneGasoil VGO Gasoil C3/C4 Olefines Iso-butane FCC naphtha CATALYTIC CRACKER (FCC) Vacuum distilation Vacuum Residue Atmospheric residue Heavy fuel oil Diesel / gasoil Jet/Kero Gasoline Naphtha LPG CRUDE- DISTILLATION HYDRO- TREATER Figure 2.4A Catalytic Cracking Reﬁnery.Crude LPG Light naphtha Isomerate ISOMERI- SATION Alkylate ALKY- LATION Heavy REFORMER Reformate H2 naphtha read more..
feature gas-oil conversion plants, such as catalytic cracking and hydrocracking units;oleﬁn conversion plants, such as alkylation or polymerization units; and coking unitsfor residuum conversion to reduce or eliminate the production of residual fuels.Modern catalytic cracking and coking reﬁneries produce large outputs of gasoline;with the remainder of their products distributed between liqueﬁed petroleum gas, jetfuel, diesel fuel, and a small quantity of coke. Many such reﬁneries also read more..
The usual practice is to blend crude oils of similar characteristics. Fluctuations inthe properties of the individual crude oils may cause signiﬁcant variations in theproperties of the blend over a period of time. Blending several crude oils prior toreﬁning can eliminate the need to change the processing conditions as frequently aswould be required, should each of the crude oils be processed individually.However, simpliﬁcation of the reﬁning procedure is not always the end read more..
the possible kerosene had been obtained, the material remaining in the still wasdiscarded. The still was then reﬁlled with petroleum and the operation repeated. Thecapacity of the stills at that time was usually several barrels (bbl) of petroleum. (1 bbl¼ 42 US. gallons¼ 34.97 Imperial gallons¼ 158.9 liters of petroleum). It oftenrequired 3 days or more to run (distill) a batch of crude oil.This simple distillation was practiced in the 1860s and 1870s, and was notoriouslyinefﬁcient. The read more..
manufacture of lubricating oils, further fractionation without cracking is necessary,and this can best be achieved by distillation under vacuum conditions (Figure 2.8).The fractions obtained by vacuum distillation include heavy gas oil, lubricating oiland asphalt, or residuum. Again, the processes in current use are discussed in moredetail elsewhere (Chapter 4).Distillation units as currently designed and used in reﬁneries are incapable ofproducing speciﬁc product fractions. In order to do read more..
the production of spirits of ﬁre (i.e., naphtha, the ﬂammable constituent of Greek ﬁre)was known almost two thousand years ago (Speight, 2007 and references citedtherein); but whether the naphtha was produced naturally, by distillation, or bycracking distillation is not clear. The occurrence of bitumen at Hit (Mesopotamia) thatwas used as mastic by the Assyrians was also developed for use in warfare though theproduction of naphtha by destructive distillation.Cracking was used commercially read more..
The yields of gasoline and kerosene fractions were usually markedly increasedby means of cracking distillation, but the technique was not entirely suitable forgasoline production. As the need for gasoline arose, the necessity of prolongingthe cracking process became apparent and led to a process known as pressurecracking.Pressure cracking was a batch operation, in which feedstock was heated to about425C (800F) in stills (shell stills) that were specially reinforced to operate atpressures as high read more..
The tar that was deposited in the separator was pumped out for use as asphalt or asa heavy fuel oil.Such a concept departed from the true batch concept and allowed a greater degreeof continuity.With the exception of the lower temperature, the tube and tank process is theforerunner of the delayed coking process. Shortly thereafter, in 1921, a moreadvanced thermal cracking process, which operated at 750–860F (400–460C),was developed (Dubbs process).The majority of regular thermal cracking read more..
2.3.4Catalytic Cracking ProcessesThis history of catalytic cracking started in the early-to-mid decades of the twentiethcentury (Table 2.2) (Germain, 1969). In the 1930s, thermal cracking units producedabout half the total gasoline manufactured, the octane number of which was about 70compared to 60 for straight-run gasoline. These were usually blended with lowerboiling fractions and sometimes with polymer gasoline and reformate, to producegasoline base stock with an octane number of about 65. read more..
reactions to produce more of the desired higher-octane hydrocarbon products. Intheory, the catalyst is not consumed in the process. In practice, due to coke and metalslay-down on the catalyst, frequent catalyst renewal is necessary. The frequency ofrenewal is dependent upon the feedstock.The last 80 years has seen substantial advances in the development of catalyticprocesses (Bradley et al., 1989; Luckenbach et al., 1992; Sadeghbeigi, 1995; Speightand Ozum, 2002; Hsu and Robinson, 2006; Gary et read more..
Sulfur compounds are changed in such a way that the sulfur content of catalyticallycracked gasoline is lower than in thermally cracked gasoline. It also produces lesscracked residuum and more of the useful gas oils, which can be used as hydrocrackerfeedstocks, than thermal cracking. However, during the cracking reaction, carbona-ceous material is deposited on the catalyst over time, which markedly reduces itsactivity, so removal of the deposit is very necessary. This is usually done by read more..
temperature to react the feedstocks and impurities with this hydrogen. The reactorsare nearly all ﬁxed-bed with catalyst replacement or regeneration done after monthsor years of operation; often at an off-site facility.In addition to the treated products, the process produces a stream of light fuelgases, hydrogen sulﬁde, and ammonia. The treated product and hydrogen-rich gas arecooled after they leave the reactor before being separated. The hydrogen is recycled tothe reactor.The commercial read more..
hydrotreat high-sulfur feedstocks prior to catalytic cracking rather than afterwards. Inthis option, several beneﬁts accrue:1.Sulfur is removed from the catalytic cracking feedstock, and corrosion is reduced in thecracking unit.2.Carbon formation during cracking is reduced so that higher conversions result.3.The cracking quality of the gas oil fraction is improved.2.3.5.bHydrocrackingHydrocracking is a more recent process development than thermal cracking, vis-breaking, and coking. In fact, read more..
Catalytic hydrocracking normally utilizes a ﬁxed-bed catalytic cracking reactorwith cracking occurring under substantial pressure (1,200 to 2,000 psi) in the presenceof hydrogen. Feedstocks are often those fractions that cannot be cracked effectively incatalytic cracking units. These include middle distillates, cycle oils, residual fuel oils,and reduced crudes; and they are often ﬁrst hydrotreated to remove impurities beforebeing sent to the catalytic hydrocracker.Sometimes hydrotreating is read more..
2.3.6ReformingReforming processes, or molecular rearrangement processes, are used for productimprovement and are processes in which the molecular structure of the feedstock isreorganized without signiﬁcantly affecting the molecular weight (Speight, 2007). Anexample is the conversion of n-hexane (molecular weight: 86) to cyclohexane(molecular weight: 84), or cyclohexane to benzene (molecular weight: 78). Theseprocesses reform or rearrange one particular molecular type to another, read more..
The dehydrogenation reactions are very endothermic, requiring the hydrocarbonstream to be heated between each catalyst bed. All but the hydrocracking reactionreleases hydrogen which can be used in the hydrotreating or hydrocracking processes.Fixed or moving bed processes are utilized in a series of three to six reactors.Feedstocks to catalytic reforming processes are usually ﬁrst hydrotreated to removesulfur, nitrogen and metallic contaminants. In continuous reforming processes,catalysts can read more..
the desired temperature, 450 to 520C (840 to 965F). It is then passed throughﬁxed-bed catalytic reactors at hydrogen pressures of 100 to 1000 psi (7 to 68 atmo-spheres) (Figure 2.11).Normally pairs of reactors are used in series, with heaters being located betweenadjoining reactors to supply the energy needed for the endothermic reactions takingplace. As many as four or ﬁve reactors may be on stream in series, while one or moreis being regenerated. The on-stream cycle of any one reactor may read more..
saturated materials (naphthenes), hydrocracking must be minimized, in order toavoid loss of the desired product. Therefore the catalytic activity must be moderatedrelative to that needed for gasoline production from a parafﬁnic feed, where dehy-drocyclization and hydrocracking play an important part.2.3.7IsomerizationThe conversion of n-parafﬁns to their respective branched-chain isomers (isomeri-zation) yields gasoline components of high octane rating in this lower boiling rangefraction read more..
inhibits oleﬁn formation, it is then passed to the reactor, at 110 to 170C (230 to340F) and 200 to 300 psi (14 to 20 atmospheres). The product is cooled, thehydrogen separated and the cracked gases are then removed in a stabilizer column.The stabilizer bottom product is passed to a superfractionator where the normalbutane is separated from the iso-butane.Current isomerization processes are used to provide additional feedstock foralkylation units or high-octane fractions for gasoline blending. read more..
2.3.8.aProcessesAlkylation processes are directed toward production of high-octane liquids foraviation gasoline. The sulfuric acid process was introduced in 1938, followed byhydrogen ﬂuoride alkylation in 1942. Rapid commercialization took place duringthe war to supply military needs, but many of these plants were shut down afterits end.In the mid 1950s, aviation-gasoline demand started to decline, but motor-gasolinerequirements rose sharply. To improve of the economics of the alkylation read more..
When the concentration of acid becomes less than 88%, some of the acid must beremoved and replaced with stronger acid. In the hydroﬂuoric acid process, the slipstream of acid is redistilled. Dissolved polymerization products are removed from theacid as thick dark oil.Hydroﬂuoric acid alkylation units require special engineering design, operatortraining and safety equipment precautions. This protects operators from accidentalcontact with hydroﬂuoric acid, which is an extremely hazardous read more..
2.3.9.aProcessesThermal polymerization is not regarded as being as effective as catalytic polymeriza-tion, but does have the advantage that it can be used for saturated materials that cannotbe induced to react by catalysts. The process consists of vapor-phase cracking ofpropane and butane followed by prolonged periods at the high temperature (510 to595C, 950 to 1100F) for the reactions to proceed to near completion.Oleﬁns can also be conveniently polymerized by means of an acid catalyst(Figure read more..
2.4Solvent MethodsSolvent deasphalting is essentially a solvent extraction process (Gary and Handwerk,2001; Speight and Ozum, 2002; Hsu and Robinson, 2006; Speight, 2007, 2008). Lowboiling parafﬁns such as propane, butane or their mixtures are used as the solvent.Light liquid parafﬁn solvent partially or completely dissolves the constituents thathave a low degree of aromaticity, and this causes asphaltenes and resins to precipitate.The dissolved components, known as deasphalted oil, are read more..
The rate of dissolution is a measure of how fast a substance dissolves. Some of thefactors determining this rate are:1.Size of the particles.2.Stirring.3.The amount of solute already dissolved.4.Temperature.In order for a solvent to dissolve a solute, the particles of the solvent must be able toseparate the particles of the solute and occupy the intervening spaces. Polar solventmolecules can effectively separate the molecules of other polar substances. Thishappens when the positive end of a read more..
until the oil dissolves, and the solution is then chilled at a slow, controlled rate indouble-pipe, scraped-surface exchangers. Cold solvent, such as ﬁltrate from theﬁlters, passes through the two-inch annular space between the inner and outer pipesand chills the waxy oil solution ﬂowing through the inner six-inch pipe.2.4.2Solvent DeasphaltingFractionation of petroleum by distillation is an excellent means for isolating andstudying the volatile constituents. The nonvolatile residuum, read more..
is usually applied to the higher molecular weight fractions of petroleum, such asatmospheric and vacuum residua, and produces asphalt or demetallized deasphaltedoil.The systematic separation of petroleum by treatment with solvents has beenpracticed for several decades (Girdler, 1965 and references cited therein). If chosencarefully, solvents effect a separation between the constituents of conventionalpetroleum, heavy oil, residua, and tar sand bitumen according to differences inmolecular weight read more..
a reproducible separation for consistent asphaltene separation. It is also preferablethat the solvents be of sufﬁciently low boiling point to allow their complete removalfrom the fraction. Most importantly, the solvent must not react with the feedstock.Hence, there has been a preference for hydrocarbon liquids. Although the severalstandard methods are available, they are not consistent in the particular hydrocarbonliquid that they specify, or in ratio of hydrocarbon liquid to weight of read more..
a maximum after approximately 8 hours. This may be ascribed to the time requiredfor the asphaltene particles to agglomerate into particles of a ﬁlterable size as well asthe diffusion-controlled nature of the process; since the heavier feedstocks also needtime for the hydrocarbon solvent to penetrate their mass.2.4.3FractionationAfter removal of the asphaltene fraction, further fractionation of petroleum is alsopossible by variation of the hydrocarbon solvent. For example, liqueﬁed gases, read more..
By deﬁnition, the saturate fraction consists, or should consist, of parafﬁns andcycloparafﬁns (naphthenes). The single-ring naphthenes,or cycloparafﬁns, present inpetroleum are primarily alkyl-substituted cyclopentane and cyclohexane. Thearomatics fraction consists of those compounds containing an aromatic ring. Theyvary from monoaromatics, containing one benzene ring in a molecule; to diaromatics,substituted naphthalene; to triaromatics, substituted phenanthrene. The resins frac-tion read more..
studies. The selection of any separation procedure depends primarily on the infor-mation desired about the feedstock.The SARA method (Jewell et al., 1974) is essentially an extension of the APImethod to allow more rapid separation of the asphaltenes by placing the two ion-exchange resins and the FeCl3-clay-anion-exchange resin packing into a singlecolumn. The adsorption chromatography of the non-polar part of the same is stillperformed in a separation operation. Since the asphaltene content of read more..
differ in content and will also be different from fractions produced by solventseparation techniques.The variety of fractions isolated by these methods and the potential for thedifferences in their composition makes it even more essential that the method used isdescribed accurately; and that it is reproducible not only when applied in any onelaboratory at different times, but also when used at different laboratories.2.4.6Propane DeasphaltingSolvent deasphalting processes are a major part of read more..
visbreaker feedstock for low-grade fuel oil. Solvent deasphalting processes have notyet realized their maximum potential for improving in process energy efﬁciency whenemployed alongside other processes. Solvent deasphalting allows removal of sulfurand nitrogen compounds, as well as metallic constituents by balancing yield with thedesired feedstock properties (Ditman, 1973).The propane deasphalting process is similar to solvent extraction; in that a packedor bafﬂed extraction tower or read more..
or replaced with a number of different ethers, which are better able to meet both thenew oxygen requirements and the vapor pressure limits.The most common ethers being used as additives are methyl tertiary butyl ether(MTBE), and tertiary amyl methyl ether (TAME). Many of the larger reﬁneriesmanufacture their own supplies of MTBE and TAME by reacting isobutylene and/or isoamylene with methanol. Smaller reﬁneries usually buy their supplies fromchemical manufacturers or the larger reﬁneries. read more..
Blending is the ﬁnal operation in petroleum reﬁning (Speight, 2007). It consists ofmixing the products in various proportions to meet speciﬁcations such as vaporpressure, speciﬁc gravity, sulfur content, viscosity, octane number, cetane index,initial boiling point, and pour point. Blending can be carried out in-line or in batchblending tanks.Storage tanks are used throughout the reﬁning process to store crude oil andintermediate process feeds for cooling and further processing. read more..
operations will have to change as wide variations in feedstock composition occur; andattempts are made to produce hydrocarbon fuels from a wide variety of biomassfeedstocks. And yet, the reﬁning industry will survive, since it is one of the mostresilient industries to commence operations during the past 150 years.In the 21st century, the petroleum industry must prepare to address many importantchallenges. Major forces for change include:1.Continuing concern for the environment.2.Governmental read more..
Dunning, H.N., Moore, J.W., 1957. Propane Removes Asphalts from Crudes. PetroleumReﬁner 36 (5), 247–250.Forbes, R.J., 1958. A History of Technology. V. Oxford University Press, Oxford, England.Gary, J.H., Handwerk, G.E., 2001. Petroleum Reﬁning: Technology and Economics, fourth ed.Marcel Dekker Inc., New York.Hoiberg, A.J. 1960. Bituminous Materials: Asphalts, Tars and Pitches, I & II. Interscience,New York.Hsu, C.S., Robinson, P.R., 2006. Practical Advances in Petroleum Processing, read more..
3 Reﬁning Chemistry3.1IntroductionCrude oil is unusable in its unreﬁned state, and must be processed into variousproducts before it can be used. These products have a hydrogen content that isdifferent from that of the original feedstock. The major reﬁnery products are liqueﬁedpetroleum gas (LPG), gasoline, jet fuel, solvents, kerosene, middle distillates, residualfuel oil, lubricating oil, and asphalt. The formation of coke from the higher molecularweight and polar constituents of a read more..
This chapter is an introduction to the chemistry involved in these conversionprocesses; so that subsequent chapters, which deal with reﬁning, and especially thereﬁnery of the future, are easier to understand.3.2Cracking3.2.1Thermal CrackingWith the dramatic increase in the number of gasoline-powered vehicles, distillationprocesses, as outlined in Chapter 2, were not able to completely ﬁll the increaseddemand for gasoline. In 1913, the thermal cracking process was developed. This is read more..
Thermal cracking is a free radical chain reaction. A free radical, in which an atomor group of atoms possesses an unpaired electron, is very reactive, and often difﬁcultto control. It is their mode of reaction that determines the product distributionobtained during thermal cracking. A signiﬁcant feature of hydrocarbon free radicals istheir resistance to isomerization. For example, thermal cracking does not increase thedegree of branching in the products (by migration of an alkyl group) above read more..
example, using a more complex hydrocarbon (dodecane, C12H26) as the reactant, twogeneral types of reaction occur during cracking:1. Primary reactions: The decomposition of high molecular weight constituents into lowermolecular weight constituents:CH3ðCH2Þ10CH3/CH3ðCH2Þ8CH3 þ CH2]CH2CH3ðCH2Þ10CH3/CH3ðCH2Þ7CH3 þ CH2]CHCH3CH3ðCH2Þ10CH3/CH3ðCH2Þ6CH3 þ CH2]CHCH2CH3CH3ðCH2Þ10CH3/CH3ðCH2Þ5CH3 þ CH2]CHðCH2Þ2CH3CH3ðCH2Þ10CH3/CH3ðCH2Þ4CH3 þ read more..
oleﬁns that have one fewer carbon atoms than their parent hydrocarbon. Cyclo-hexane produces hydrogen, ethylene, butadiene, and benzene. Alkyl-substitutedcycloparafﬁns decompose principally by means of scission of the alkyl chain toproduce an oleﬁn and predominantly methyl or to a lesser extent ethyl cyclohexane.The aromatic ring is fairly resilient to decomposition at moderate crackingtemperatures (350 to 500C, 660 to 930F). However, alkylated aromatics, like thealkylated naphthenes, are read more..
ﬁrst-order process. However, it is deﬁnite that there is an induction period beforecoke begins to form, which seems to be triggered by phase separation of reactedasphaltene product (Magaril et al., 1971 and references cited therein; Speight,1987; Wiehe, 1993 and references cited therein; Speight 2003 and references citedtherein). The organic nitrogen originally present in the asphaltenes invariablyundergoes thermal reaction to concentrate in the nonvolatile coke (Speight, 1970,1989; Vercier, read more..
As an example of a thermal cracking process, in delayed coking, the feedstock isheated to high temperatures (480 to 500C; 895 to 930F) in a furnace, and thenreaction is allowed to continue in a cylindrical, insulated drum. The volatile productspass overhead into a fractionator and coke accumulates in the drum. Any high-boilingliquid product from the fractionator is recycled to the coker furnace. When the drumﬁlls up with coke, the reacting feedstock is directed to a second drum. The coke read more..
5. The interaction of the products with the original constituents.6. The inﬂuence of the products on the composition of the liquids.To mitigate coke formation, it is necessary to eliminate or modify the primarychemical reactions that form incompatible products, particularly those reactions inwhich insoluble lower molecular weight products (carbenes and carboids; Figure 3.1)are formed (Speight, 1987; Speight, 1992; Wiehe, 1992; Wiehe, 1993a, 1993b;Speight 2007 and references cited read more..
Visbreaking (Figure 3.3) (Chapter 5) is primarily a means of reducing the viscosityof heavy feedstocks, such as residua, by controlled thermal decomposition; as theproducts emanating from the reactor are quenched before complete conversion canoccur (Speight and Ozum, 2002). Low residence times are required to avoid coking,although additives can help to suppress coke deposits on the tubes of the furnace(Allan et al., 1983).The process consists of a reaction in a furnace, followed by quenching read more..
The temperature and residence time of the asphaltene constituents in the reactorare key to the successful operation of a visbreaker. This needs to operate underconditions that avoid the formation of insoluble sediment (often referred to as coke).However, there is a break point above which sediment deposition increases(Figure 3.4).The most polar (amphoteric) constituents of the asphaltene fraction are morereactive than the less polar constituents (Speight, 2007 and references cited therein).The read more..
The net overall rate of thermal cracking follows the Arrhenius relationship, i.e.:k¼ AeÀE=RTWhere k is the reaction rate, A is the frequency factor, E is the activation energy, andR is the gas constant.Thus, the rate of thermal cracking reaction(s) is an exponential function oftemperature, and the degree of conversion is, therefore, a function of both time andtemperature. This allows the use of a lower temperature if the contact time (in thereactor) is increased, providing this does not change read more..
Once formed, carbonium ions promote several reaction pathways. For example,isomerization by hydride ion or methyl group shift occurs readily. The driving forceof the reaction is the stabilization of the carbonium ion. This is achieved by movingthe charged carbon atom toward the center of the molecule, hence the isomerizationofa-oleﬁns to internal oleﬁns when carbonium ions are produced.Cyclization also occurs by internal addition of a carbonium ion to a double bondwith the formation of a read more..
Alkylbenzenes with attached groups of C2 or larger form benzene and the corre-sponding oleﬁns; in nearly quantitative dealkylation reactions below 500C (930F),with their heat sensitivity increasing with the size of the alkyl group.3.2.2.bCoke FormationCoke formation is an undesirable side reaction of catalytic cracking. The carbene/carboid-type species can produce many products, but the most damaging remain onthe catalyst surface and cannot be desorbed. This results in the formation of coke, read more..
catalyst decay is not related in any simple way to the hydrogen-to-carbon ratio of thecoke, or to the total coke content of the catalyst, or any simple measure of cokeproperties. Moreover, despite many and varied attempts, there is currently noconsensus as to the detailed chemistry of coke formation.3.3HydroprocessesHydroprocesses (hydrogenation processes) that convert petroleum to petroleumproducts may be classiﬁed as either destructive or nondestructive. The former ischaracterized by the read more..
The effect of hydrogen on naphthenic hydrocarbons is mainly to promote ringscission, followed by immediate saturation of each end of the fragments produced.For example, methyl-cyclopentane is converted (over a platinum-carbon catalyst) to2-methylpentane, 3-methylpentane, and n-hexane.Aromatic hydrocarbons are resistant to hydrogenation under mild conditions; butunder more severe conditions they are converted to naphthenic rings, which may alsobe converted to parafﬁns. Scissions also occur read more..
make up 25 to 50% of the catalysts. Pentasils (silicalite or ZSM-5) may be included indewaxing catalysts.These catalysts, such as nickel (5% by weight) on silica-alumina, work best onfeedstocks that have been hydrotreated to low nitrogen and sulfur levels. The catalystthen operates well at 350 to 370C (660 to 700F) and a pressure of about 1500 psito give good conversion of feed to lower boiling liquid fractions, with minimumsaturation of single-ring aromatics and a high iso-parafﬁn to read more..
a single activation energy model (Schucker, 1983). The complexity of the individualreactions occurring in a residuum, and the interference of secondary and tertiaryproducts with those from other components of the mixture is unpredictable.Recognition that the thermal behavior of petroleum is related to its compositionhas led to a multiplicity of attempts to classify petroleum and its fractions ascompositions of matter. As a result, various analytical techniques have been devel-oped for the read more..
Deposition of solids or incompatibility is still possible when asphaltenes interactwith catalysts, especially acidic support catalysts; through their functional groups,i.e., the basic nitrogen species, just as they interact with adsorbents. Asphaltenes mayinteract with the catalyst through the agency of a single functional group, whilst theremainder of the asphaltene molecule remains in the liquid phase. There is also a lessdesirable option in which the asphaltene reacts with the catalyst at read more..
to those of the sulfur compounds and follow a stepwise mechanism to produceammonia and the relevant substituted aromatic compound.Hydrotreating catalysts consist of metals impregnated on a porous aluminasupport. The surface of the catalyst is spread across all of the pores of the alumina(200 to 300 m2/g). These metals are dispersed in a thin layer over this entire internalalumina surface. This type of catalyst hence has a huge catalytic surface for a givenweight. Cobalt (Co), molybdenum (Mo), read more..
3.4.1DehydrogenationDehydrogenation is the removal of hydrogen from the parent molecule. For example,at 550C (1025F) n-butane (C4H10) loses hydrogen to produce 1-butene(CH3CH2CH¼CH2) and 2-butene (CH3CH¼CHCH3). The development of selectivecatalysts, such as chromic oxide (chromia, Cr2O3) on alumina (Al2O3), has renderedthe dehydrogenation of parafﬁns to oleﬁns particularly effective, and the formation ofhigher molecular weight material is minimized.The extent of dehydrogenation (vis-a`-vis read more..
to liquid hydrocarbons in the gasoline boiling range. The process can be used toincrease the octane number of the parafﬁns boiling in the gasoline range by convertingsome of the n-parafﬁns present into iso-parafﬁns.The process involves contacting the hydrocarbon with a catalyst under conditionsfavorable to good product recovery. The catalyst may be aluminum chloride promotedwith hydrochloric acid, or a platinum-containing catalyst. Both are very reactive andcan lead to undesirable side read more..
rupture may also occur in any side chains to produce polymethyl derivatives;whereas cyclopentane (C5H10) and cyclohexane (C6H12) rings may expand andcontract, respectively.The isomerization of alkyl aromatics may involve changes in the side-chainconﬁguration, disproportionation of the substituent groups, or their migration aboutthe nucleus. The conditions needed for isomerization within attached long side chainsof alkylbenzenes and alkylnaphthalenes are also those that are optimal for the read more..
In the petroleum industry, polymerization is used to indicate the production ofgasoline components that fall into a speciﬁc (and controlled) molecular weight range,hence the term polymer gasoline. Furthermore, it is not essential that only one type ofmonomer be involved:CH3CH]CH2 þ CH2]CH2/CH3CH2CH2CH]CH2This type of reaction is more correctly called copolymerization. Polymerization in thetrue sense of the word is usually prevented, and every attempt is made to terminate thereaction at the read more..
present in the petroleum feedstock, may also be present in liquid fuels and otherproducts. This is often the case, although they may have undergone some skeletalchanges induced by the reﬁning processes. However, instability/incompatibility is notdirectly related to the total nitrogen, oxygen, or sulfur content; the formation of color/sludge/sediment is a result of several factors. Incompatibility in petroleum productscan be linked to the presence of several different deleterious heteroatomic read more..
when various fractions from different types of crude oil are blended, or are allowed toremain under conditions of storage (prior to use), and a distinct phase separates from thebulk product (Batts and Fathoni, 1991; Por, 1992; Mushrush and Speight, 1995).3.5.1Deﬁnitions and TerminologyThis section deﬁnes some of the terms used in the liquid fuels ﬁeld; so that their uselater in the text will be more apparent and will also alleviate some potential formisunderstanding.The general scientiﬁc read more..
the gum content and the solid precipitate are measured. A similar test, also using anaccelerated oxidation procedure, is used for determining the oxidative stability ofdiesel fuel (ASTM D2274), steam turbine oil (ASTM D2272), distillate fuel oil(ASTM D2274), and lubricating grease (ASTM D942).Dry sludge is deﬁned as the material that is separated from petroleum and itsproducts by ﬁltration, and which is insoluble in heptane. The test is used as anindicator of process operability, and as a read more..
during initial processing. For example, crude oil is known to pick up iron and othermetal contaminants from contact with pipelines and pumps.3.5.2General ChemistryThe chemistry and physics of incompatibility can, to some extent, be elucidated(Wallace, 1969; Hardy and Wechter, 1990b; Por, 1992; Power and Mathys, 1992;Mushrush and Speight, 1995), but many unknowns remain. The mechanisms that areoccurring are likely to involve factors such as the following:1. Speciﬁc interactions between read more..
the crude oil and the aqueous phase can be removed from the system. Phase sepa-ration can be accomplished either by the use of suitable surface active agents, or byuse of a high-voltage electric ﬁeld after admixing with water at a rate of about 5% andat a temperature of about 100C (212F)Each emulsion has its own structure and characteristics, which will determine itssusceptibility to the various surface-active agents that are used for breaking them up.Hence, appropriate emulsion breaking read more..
material is generally more susceptible to sludge formation, presumably because of thehigher level of polar/asphaltic constituents that it contains.3.5.4.cVolatilityPetroleum can be subdivided by distillation into a variety of fractions of differentboiling ranges or cut points. In fact distillation was, and still is, the method forfeedstock evaluation for various reﬁnery options. So it is not surprising that tests todetermine the volatility of petroleum and petroleum products were among the read more..
3.5.4.dViscosityThe viscosity of a feedstock varies with its origin, type, and its chemical composition;particularly that of the polar functions where intermolecular interactions can occur.For example, there is a gradation of viscosity between conventional crude oil, heavyoil, and bitumen (Speight, 2008).Viscosity is a measure of ﬂuidity properties and consistencies at a given temper-ature. Heavier crude oils, i.e. crude oils of lower API gravity, have usually higherviscosity. An increase in read more..
temperature intervals of 1C(2F). If conditions or oil properties are such thatreduced temperatures are required to determine the pour point, alternate tests areavailable that accommodate the various types of samples.3.5.4.gAcidityThe acidity of petroleum or petroleum products is usually measured in terms of theacid number; which is deﬁned as the number of milli-equivalents per gram of alkalirequired to neutralize the petroleum sample (ASTM D664, ASTM D974, ASTMD3242).Acidity due to the read more..
Metals content above 200 ppm are considered to be high, but the range is verylarge. The higher the mineral matter content, the higher is the tendency of the crudeoil to form sludge or sediment.3.5.4.iWater Content, Salt Content, and Bottom Sediment and WaterWater content (ASTM D4006, ASTM D4007, ASTM D4377, ASTM D4928) saltcontent (ASTM D3230), and bottom sediment/water (BS&W) (ASTM D96, ASTMD1796, ASTM D4007) indicate the concentrations of aqueous contaminants present inthe crude, either read more..
Loss of side chains always accompanies thermal cracking; dehydrogenation andcondensation reactions are favored by hydrogen deﬁcient conditions.The initial stages of the thermal decomposition of asphaltenes are the least wellunderstood part of the entire process. It is known that overall thermal decompositioninvolves scission of carbon-carbon bonds, aromatization of naphthenic ring systems,formation of lower molecular weight material, and formation of coke. It is also knownthat the presence of read more..
The phase separation phenomenon that is the prelude to coke formation can also beexplained by use of the solubility parameter (d) for petroleum fractions and the solvents(Speight, 1992, 1994, 2007 and references cited therein). Although little is knownabout the solubility parameter of petroleum fractions, there has been a noteworthyattempt to deﬁne the solubility parameter ranges for different fossil fuel liquids.As these concepts show, characterization data can be used to understand read more..
Mitchell, D.L., Speight, J.G., 1973. Fuel 52, 149.Mushrush, G.W., Beal, E.J., Hazlett, R.N., Hardy, D.R., 1990. Energy & Fuels 5, 258.Mushrush, G.W., Hardy, D.R., 1994. Preprints. Div. Fuel Chem. American Chemical Society,Washington, DC. 39: 904.Mushrush, G.W., Hazlett, R.N., Pellenbarg, R.E., Hardy, D.R., 1991. Energy & Fuels 5, 258.Mushrush, G.W., Speight, J.G., 1995. Petroleum Products: Instability and Incompatibility.Taylor & Francis Publishers, Washington, DC.Olmstead, W.N., read more..
Speight, J.G., 2004. New Approaches to Hydroprocessing. Catalysis Today 98 (1–2), 55–60.2004.Speight, J.G., 2007. The Chemistry and Technology of Petroleum, fourth ed. CRC Press,Taylor & Francis Group, Baca Raton, Florida.Speight, J.G., 2008. Handbook of Synthetic Fuels. McGraw-Hill, New York.Speight, J.G., Moschopedis, S.E., 1979. Fuel Processing Technology 2, 295.Speight, J.G., Ozum, B., 2002. Petroleum Reﬁning Processes. Marcel Dekker Inc, New York.Stavinoha, L.L., Henry, C.P. read more..
4 Distillation4.1 IntroductionIn early reﬁneries, distillation was the primary means by which products wereseparated from crude petroleum. As the technologies for reﬁning evolved, theybecame much more complex; but distillation still remained the prime means by whichpetroleum was reﬁned. Indeed, the distillation section of a modern reﬁnery is its mostﬂexible unit; since conditions can be adjusted to process a wide range of feedstocksfrom the lighter crude oils to the heavier, more read more..
terms of coping with variable quality of feedstock and range of product yields(Figure 4.3). The maximum permissible temperature of the feedstock in the vapor-izing furnace determines the possible range of products in a single-stage (atmo-spheric) column. Thermal decomposition or cracking of the constituents beginsaround 350C (660F) and the rate increases markedly above this temperature. This isundesirable because the coke-like material produced tends to be deposited on thetubes, with consequent read more..
for all column types, ﬂow regimes vary greatly depending on the internal elementsused. The two main types in use are tray and packed columns, the latter beingequipped with either random or structured packing. Different types of distillationcolumns are used for different purposes, depending on the desired liquid holdup,Figure 4.3Variation of Distillate Yields and Distillate Composition for Different Feedstocks.Source: Speight, J.G. 2007. The Chemistry and Technology of Petroleum 4th Edition. read more..
capacity (ﬂow rates), and pressure drop; but they are all complex units, combiningmany structural elements.It is common practice to only use furnaces to heat the feedstock when distillationtemperatures above 205C (400F) are required. Lower temperatures, such as thatused in the redistillation of naphtha and similar low-boiling products, are provided byheat exchangers and/or steam reboilers.The feed to a fractional distillation tower is heated by ﬂow through pipes arrangedwithin a large read more..
fractionating crude petroleum may be 13 feet in diameter and 85 feet high; but a towerfor stripping unwanted volatile material from gas oil may be only 3 or 4 feet indiameter and 10 feet high. Towers for the distillation of liqueﬁed gases are only a fewfeet in diameter, but may be up to 200 feet in height. A tower used in the fractionationof crude petroleum may have from 16 to 28 trays, but one used in the fractionation ofliqueﬁed gases may have 30–100 trays. Typically, the feed to a tower read more..
point or on any one tray remaining fairly consistent. This allows part of the reﬂuxingliquid to be tapped off at various points as sidestream products. Thus, in the distil-lation of crude petroleum, light naphtha and gases are removed as vapor from the topof the tower. Heavy naphtha, kerosene, and gas oil are removed as sidestreamproducts, and reduced crude is taken from the bottom.The efﬁcient operation of the distillation, or fractionating, tower requires the risingvapors to mix with the read more..
Topped crude oil must always be stripped with steam to elevate the ﬂash point or torecover the ﬁnal portions of gas oil. The composition of the topped crude oil isa function of the temperature of the vaporizer (or ﬂasher). In addition, the propertiesof the residuum are very dependent upon the extent of volatiles removal by eitheratmospheric distillation or by vacuum distillation (Table 4.1).4.2.2Vacuum DistillationVacuum distillation evolved due to the need to separate the less volatile read more..
Table 4.1Properties of Various Residua.FeedstockGravitySulfurNitrogenNickelVanadiumAsphaltenesCarbon residueAPI(heptane)(Conradson)wt. %wt. %ppmppmwt. %wt. %Arabian Light.>650 F17.73.00.210.026.01.87.5Arabian Light,>1050 F18.104.22.1684.066.04.314.2Arabian Heavy,> 650 F22.214.171.1247.0103.08.014.0Arabian Heavy,>1050 F126.96.36.1990.0174.010.019.0Alaska, North Slope,>650 F188.8.131.528.030.02.08.5Alaska, North Slope,>1050 F184.108.40.2067.082.04.018.0Lloydminster (Canada),>650 read more..
When trays similar to those used in atmospheric columns are used in vacuumdistillation, the column diameter may be extremely high; up to 45 feet. To maintainlow pressure drops across the trays, the liquid seal must be minimal. The low holdupand the relatively high viscosity of the liquid limit the tray efﬁciency. This tends to bemuch lower than in the atmospheric column. A vacuum is maintained in the columnby removing the non-condensable gas that enters the column, in the feed to thecolumn or read more..
produce lubricating base oil. The short residue is normally used as feedstock for thesolvent deasphalting process to produce deasphalted oil, an intermediate for brightstock manufacturing. High-vacuum units for asphalt production are designed toproduce straight-run asphalt and/or feedstocks for residuum blowing to produce blownasphalt. In principle, these units are designed on the same basis as feed preparationunits. These may also be used to provide feedstocks for asphalt manufacturing.Deep cut read more..
column, as well as external ﬂows of feeds and product streams into and out ofthe column.The column is divided into a number of horizontal sections by metal trays orplates, and each is the equivalent of a still. The more trays, the more redistillation, andhence the better is the fractionation or separation of the mixture fed into the tower.A tower for fractionating crude petroleum may be 13 feet in diameter and 85 feethigh, the height being determined by a general formula:c¼ 220d2rWhere c is read more..
coming through the perforated tray; with possible leakage of liquid dropping throughthe upper tray.Usually, trays are horizontal, ﬂat, specially prefabricated metal sheets, which areplaced at a regular distance in a vertical, cylindrical column. Trays have two mainparts: (1) the part where vapor (gas) and liquid are being contacted – the contactingarea and (2) the part where vapor and liquid are separated, after having been incontact – the downcomer area.Classiﬁcation of trays is based read more..
3.Tthe vapor rate at the “lower limit”, i.e., the minimum vapor load.4.The tray pressure drop.The separation performance of a tray is the basis of the performance of the column asa whole. The primary function of a distillation column is the separation of a feedstream into (at least) one top product stream and one bottom product stream. Thequality of the separation performed by a column can be judged from the purity of thetop and bottom product streams. The speciﬁcation of the impurity read more..
components and thus reduce the ﬂash point of these products. Thus a sidestreamproduct enters at the top tray of a stripper, and as it spills down the four to six trays,steam injected into the bottom of the stripper removes the volatile components. Thesteam and volatile components leave the top of the stripper to return to the maintower. The stripped sidestream product leaves at the bottom, after being cooled ina heat exchanger, goes to storage. Since strippers are short, they are arranged read more..
Stabilization is usually a more precise operation than that just described. Anexample can be seen in the handling of the mixtures of hydrocarbons produced bycracking. The overhead from the atmospheric distillation tower that fractionates thecracked mixture consists of light ends, together with cracked gasoline with light endsdissolved in it. If the latter is pumped to the usual type of tank storage, the dissolvedgases cause the gasoline to boil, meaning they, and some of the liquid components read more..
and higher boiling hydrocarbons is now termed fat oil. This is pumped from thebottom of the absorber into the second tower. The second tower is where fractionaldistillation separates the butane and higher boiling hydrocarbons as an overheadfraction and the oil. Once again lean oil, is the bottom product.The condensed butane and higher boiling hydrocarbons are included with thereﬁnery casinghead bottoms or stabilizer bottoms. The dry gas is frequently used asfuel for reﬁnery furnaces. It read more..
80C (176F), but if it is mixed with hexane, it distills at 69C (156F). A mixture thatboils at a temperature lower (or higher) than the boiling point of either of thecomponents is called an azeotropic mixture.Two main types of azeotropes exist; a homogeneous azeotrope, where a singleliquid phase containing the two components is in equilibrium with a vapor phase; anda heterogeneous azeotrope, where the liquid mixture separates into two liquid phases,which are identical in composition to the vapor read more..
Many different residue curve maps are possible when azeotropes are present.Ternary mixtures containing only one azeotrope may exhibit six possible residuecurve maps that differ by the binary pair forming the azeotrope, and by whether theazeotrope is minimum or maximum boiling. By identifying the limiting separationachievable by distillation, residue curve maps are also useful in synthesizing sepa-ration sequences that combine distillation with other methods.The separation of components of read more..
bottoms product of butenes and the extractive solvent are fed to a second columnwhere the butenes are removed as overhead. The acetone-water solvent from the baseof this column is recycled to the ﬁrst column. Extractive distillation may also be usedfor the continuous recovery of individual aromatics; such as benzene, toluene, orxylene(s); from the appropriate petroleum fractions. Prefractionation concentratesa single aromatic cut into a close-boiling cut, after which the aromatic concentrate read more..
to be removed in the distillate. Formation and disruption of hydrogen bonds are oftenassociated with strong negative and positive deviations, respectively, from Raoult’s Law.d.Select candidate solvents from chemical groups that tend to show higher polarity thanone key component or lower polarity than the other key.2.Identify the individual candidate solvents.a.Select only candidate solvents that boil at least 30–40C above the key components toensure that the solvent is relatively read more..
There is also the potential for applying catalytic distillation or reactive distillationto the deep distillation of heavy oil. These are processes where catalyst and distil-lation devices are united in the same equipment. They are discussed further in section220.127.116.11.4 Process InnovationsHeavy and/or sour crude oil, which require more energy-intensive processing thanconventional (light, sweet) crude oils, are expected to become a signiﬁcant fraction ofthe feedstock for hydrocarbon fuels read more..
The distillation tower was re-designed to work at low pressure and the outputs werechanged to link to the other processes and product mix of the reﬁnery. The designresulted in reduced fuel consumption and better heat integration. Such options will bemore obvious in future reﬁneries.In general, reﬁneries of the future will optimize energy use through more efﬁcientheat exchange and heat integration, better controls, and no doubt will adopt energy-saving approaches to very energy-intensive read more..
existing tray support rings, and the internals. The use of better internals obviouslypromotes debottlenecking but is very expensive. Of concern to us are the costs of newtypes of internals, costs of removing the existing internals, and the opportunity cost ofextensive plant downtime.In the near future, maximization of the useful capacity of column internals, eitherwith trays, structured or random packing will be done with customized feeddistributors, downcomers and other fabricated read more..
removal, catalyst fouling resistance, and selective hydrogenation performances bymodifying the reaction mixture composition along the column.The suitability of reactive distillation for a particular reaction depends on variousfactors; such as the volatilities of reactants and products, or feasible reaction anddistillation temperatures. Hence, it may not be applicable to every reaction. Exploringcandidate reactions for this process is an area that could be proﬁtable, however.The beneﬁts of read more..
coupled with a selective transport of the product through a membrane (Scouten,1997).An extensive study, funded by DoE, focused on membranes for different separa-tions (gas/gas, ﬂuid/ﬂuid); and studied current state-of-the-art and potential futureapplications in petroleum reﬁning (Dorgan et al., 2003). The report concludes thatmembrane technology will deﬁnitely enter the reﬁnery. Further research is needed todevelop appropriate materials that can withstand the environment found in read more..
of the corrosive elements; and further hydrogen chloride may be produced by thethermal treatment that occurs as part of the distillation process. Inadequate desaltingcan cause fouling of heater tubes and heat exchangers throughout the reﬁnery. Foulingrestricts product ﬂow and heat transfer, and leads to unit failures due to increasedpressures and temperatures.Corrosion occurs in various forms in the distillation section of the reﬁnery. This ismanifested by events such as pitting corrosion read more..
noise, and electrical resistance. The techniques have generally had slow reportingrates in the past (minutes or hours), and have been limited by process conditions andsources of error. Now, newer technologies can report rates up to twice per minute withmuch higher accuracy, this is referred to as real-time monitoring. This allows processengineers to treat corrosion as another process variable that can be optimized in thesystem. Immediate responses to process changes allow the control of read more..
changes may provide adequate corrosion control if there is the possibility of reducingcharge rate and temperature.Process changes will include any action to remove, or at least reduce, the amountof acid gas present and to prevent accumulation of water on the tower trays. Materialupgrading will include lining of distillation tower tops with alloys resistant tohydrochloric acid. Design changes will be used to prevent the accumulation of waterand will include coalescers and water draws. The read more..
reduction in the absolute pressure of a vacuum distillation column. Operation of a vacuumdistillation tower at lower absolute pressures results in increased yield of desirable vacuumdistillation products.United States Patent 7,204,928. April 17, 2007. Process and apparatus for the fractional distil-lation of crude oil. Cerea, G.A process for the fractional distillation of crude oil, which comprises the steps of: feedinga continuous current of crude oil at 310 to 400C. into a turbomixer read more..
5 Thermal Cracking5.1IntroductionBalancing product yield and market demand, without the manufacture of largequantities of fractions having low commercial value, has long required processes forthe conversion of hydrocarbons of one molecular weight range and/or structure intosome other molecular weight range and/or structure. The basic processes forachieving this are cracking processes, in which high boiling constituents of petroleumare cracked, or thermally decomposed, into lower molecular read more..
3.Thermal reforming.4.Catalytic reforming.5.Polymerization.6.Alkylation.7.Coking.Each of these processes may be carried out in a number of ways. These differ in thedetails of their operation, or essential equipment, or both (Speight and Ozum, 2002;Hsu and Robinson, 2006; Gary et al., 2007; Speight, 2007).When petroleum fractions are heated to temperatures over 350C (660F) in theabsence of a catalyst, thermal decomposition proceeds at a signiﬁcant rate (Chapter3). The severity of thermal read more..
The products that are formed depend on temperature and residence time. Isomeri-zation of the products; and secondary even tertiary reactions can, and do, occur thatcomplicate these reaction schemes considerably.The least thermally stable hydrocarbons are the parafﬁns, but the oleﬁnsproduced by the cracking of parafﬁns are also reactive. Cycloparafﬁns (naphthenes)are less easily cracked. Their stability altering mainly if any side chains are present,but ring splitting may occur, and read more..
5.2.1Thermal CrackingThe majority of thermal cracking processes use temperatures of 455 to 540C (850to 1005F) and pressures of 100 to 1000 psi; the Dubbs process may be taken asa typical application of an early thermal cracking operation.In the process, feedstock (reduced crude) is preheated by direct exchange with thecracking products in the fractionating columns. Cracked gasoline and heating oil areremoved from the upper section of the column. Light and heavy distillate fractions areremoved read more..
refractory with each pass through the thermal zone; and if such oils are not required asa fuel oil stock they may be subjected to a coking operation to increase gasoline yieldor further reﬁned by means of a hydrogen process.The process is a relatively low-cost and low severity approach to improving theviscosity characteristics of the residue without attempting signiﬁcant conversion todistillates. Low residence times are required to avoid coke formation, althoughadditives can help in the read more..
Figure 5.1A Soaker Visbreaker.Source: OSHA Technical Manual, Section IV, Chapter 2: Petroleum Reﬁning Processes. http://www.osha.gov/dts/osta/otm/otm_iv/otm_iv_2.htmlTable 5.1Examples of Product Yields and Properties from Visbreaking Athabasca Tar SandBitumen and Feedstocks Having a Similar API Gravity.ArabianLightArabianLightIranianLightVacuumVacuumVacuumAthabascaFeedstockResiduumResiduumResidueBitumenAPI gravity18.104.22.168.6Carbon residue*20.322.013.5Sulfur, wt. %4.04.03.54.8Product yields**, read more..
Product quality and yields from the coil and soaker drum design are essentially thesame at a speciﬁed severity, being independent of visbreaker conﬁguration. Byproviding the residence time required for achieving the desired reaction; the soakerdrum design allows the heater to operate at a lower outlet temperature, thereby savingfuel, but it does have some disadvantages.The main disadvantage of the soaker visbreaking process is the necessity to decokethe heater and the soaker drum; although read more..
require more frequent de-coking than soaker drums, but the need to take the latter outof service normally requires a complete halt to the operation.The lower temperatures used in the soaker approach mean that these units use lessfuel. In cases where a reﬁnery buys fuel to support process operations, any savings infuel consumption could be extremely valuable. In such cases, soaker visbreaking maybe advantageous.The Shell soaker visbreaking process is suitable for production of fuel oil read more..
unsaturated compounds. For example, thermal cracking at low pressure producesoleﬁns (and di-oleﬁns), particularly in the naphtha fraction. These tend to undergosecondary reactions to form gum and intractable, non-volatile tar.The reduction in viscosity of distillation residues tends to reach a limiting valuewith conversion, although the total product viscosity can continue to decrease. Theminimum viscosity of the unconverted residue can lie outside the range of allowableconversion if read more..
In the process, the feedstock is introduced into the product fractionators, where it isheated and lighter fractions are removed as side-stream products. The bottoms,including a recycle stream of heavy product, are then heated in a furnace (outlettemperature: 480 to 515C, 895 to 960F). The heated feedstock enters one of a pairof coking drums where the cracking reactions continue. The cracked products leave asan overhead stream and coke deposits form on the inner surface of the drum. To read more..
Table 5.3Product Yields and Product Properties for Delayed Coking of Athabasca Tar Sand Bitumen and Similar Low API Gravity Feedstocks.KuwaitWest TexasTia JuanaAlaska NSArabian LightAthabascaFeedstockResiduumResiduumResiduumResiduumResiduumBitumenAPI gravity22.214.171.124.46.97.3Carbon residue*19.817.822.018.117.9Sulfur, wt. %5.23.02.92.04.05.3Product yields, vol. %Naphtha (95-425F, 35-220C)26.728.925.612.519.120.3Light gas oil (425-645F, 220-340C)28.016.526.4******Heavy gas oil (645-1000F, read more..
Fractionators separate the overhead products into fuel gas (low molecular weightgases up to and including ethane), propane and propylene (CH3CH2CH3 andCH3CH¼CH2), butane and butylene (CH3CH2CH2CH3 and CH3CH2CH¼CH2),naphtha, light gas oil, and heavy gas oil. Yields and product quality vary widely due tothe broad range of feedstock types. There is a decrease in overhead yield with increasein asphaltene content of the feedstock (Schabron and Speight, 1997; Speight andOzum, 2002; Hsu and Robinson, read more..
Table 5.4Product Yields and Product Properties for Fluid Coking Low API Gravity Feedstocks.LA BasinKuwaitHawkinsTia JuanaArabianHeavyIranianHeavyBachaqueroZacaVacuumVacuumVacuumVacuumVacuumVacuumVacuumVacuumFeedstockResiduumResiduumResiduumResiduumResiduumResiduumResiduumResiduumAPI gravity126.96.36.199.188.8.131.52.7Carbon residue*17.021.824.522.024.421.421.419.0Sulfur, wt. %184.108.40.206.220.127.116.11.8Product yields**, vol. %Naphtha (95-425F, 35-220C)17.021.019.520.715.015.414.720.5Gas oil (425-1000F, read more..
a vacuum tower at 260 to 370C (500 to 700F) is injected directly into the reactor.The temperature in the coking vessel ranges from 480 to 565C (900 to 1050F).The pressure is close to atmospheric pressure, so the incoming feed is partly vapor-ized and partly deposited on the ﬂuidized coke particles. The feedstock then cracksand vaporizes, leaving a residue that dries to form coke. The vapor products passthrough cyclones that remove most of the entrained coke particles.The vapor is discharged read more..
The typical bed temperature in the burner is of the order of 590 to 650C (1095to 1200F); the air is added as needed to maintain the temperature by burning part ofthe product coke. The pressure in the burner may range from 5 to 25 psi. Flue gasesfrom the burner bed pass through cyclones and discharge to the stack. Hot coke fromthe bed is returned to the reactor through a second riser assembly.Coke is one of the products of the process, and it must be withdrawn from thesystem to keep the solids read more..
required. Units are designed to gasify 60 to 97% of the coke from the reactor. Evenwith the gasiﬁer, the product coke will contain more sulfur than the feed. This limitsthe attractiveness of even the most advanced of coking processes.5.3Process Options for Heavy FeedstocksThermal cracking processes offer viable methods for conversion of heavy feedstocks;as they enable use of low operating pressures, without requiring expensive catalysts.Currently, the most widely used residuum conversion read more..
completion and coke is the eventual product (Chapter 3) (Speight and Ozum, 2002;Hsu and Robinson, 2006; Gary et al., 2007; Speight, 2007).Innovations have been initiated in thermal cracking processes over the past twodecades. This enables them to be used to process heavy feedstocks such as tar sandbitumen. They offer attractive methods for the conversion of heavy oil and bitumensince low a operating pressure is needed, along with high operating temperature,without requiring expensive catalysts. read more..
equipment. In addition, the Aquaconversion process can be implanted in theproduction area, and thus the need for external diluent and its transport over largedistances is eliminated.5.3.2Asphalt Coking Technology (ASCOT) ProcessThe ASCOT process is a residual oil upgrading process that integrates the delayedcoking process and the deep solvent deasphalting process (low energy deasphalting,LEDA) (Bonilla, 1985; Bonilla and Elliot, 1987; Hydrocarbon Processing, 1996).Removing the deasphalted oil read more..
petroleum residues at conditions between those of conventional visbreaking anddelayed coking. Although coal is added to the feedstock, it is not intended to be aco-processing feedstock but to act as a scavenger to prevent the build-up of coke onthe reactor wall.The feedstock is mixed with coal powder in a slurry mixing vessel (withouta catalyst or hydrogen). It is then heated in the furnace and fed to the reactor, wherethe feedstock undergoes thermal cracking reactions for several hours at a read more..
The cracked oil and gas products, together with steam from the top of the reactor,are introduced into the fractionator. This is where the oil is separated into two frac-tions; cracked light oil and vacuum gas oil, and pitch (Speight and Ozum, 2002; Hsuand Robinson, 2006; Gary et al., 2007; Speight, 2007).5.3.6Eureka ProcessThe Eureka process is a thermal cracking process to produce a cracked oil andaromatic residuum from heavy residual materials (Aiba et al., 1981; Speight andOzum, 2002; Hsu and read more..
a conventional delayed coker, a higher cracked oil yield can be obtained. A widerange of residua can be used as feedstock, such as atmospheric and vacuum residuesof petroleum crude oils, various cracked residues, asphalt products from solventdeasphalting and native asphalt. After hydrotreating, the cracked oil is used asfeedstock for a ﬂuid catalytic cracker or hydrocracker.The original Eureka process uses two batch reactors, while the newer ET II and theHSC process both employ continuous read more..
oil fraction. The cracked gas product is compressed and used as reﬁnery fuel gasafter sweetening. The cracked oil product is used as ﬂuid catalytic cracking orhydrocracker feedstock after hydrotreating. The residuum is suitable for use as boilerfuel, road asphalt, binder for the coking industry, or as a feedstock for partialoxidation.5.3.9Mixed-Phase CrackingMixed-phase cracking (also called liquid-phase cracking) is a continuous thermaldecomposition process for the conversion of heavy read more..
from this drum is pumped to the distillate heater, which typically operates at a pres-sure of approximately 490C (915F) and 290 psi. Under these conditions, thecracking reactions take place in the liquid phase (Figure 5.7).Fluid from the distillate heater is then routed to a combi-tower, where separation isachieved between residue, gas oil, and lighter products. In addition, a heavy gas oilfraction is withdrawn, returned to the surge drum, and then recycled through thedistillate heater. The read more..
The feedstock and product requirements of the thermal distillate cracking processare ﬂexible; and the process has the capability to optimize conversion throughadjustment of the heavy gas oil recycle rate.The Shell deep thermal gasoil process is a combination of the Shell deep thermalconversion process and the Shell thermal gasoil process. In this alternative highconversion scheme, the heavy gas oil (HGO) from the atmospheric distillationunit and the vacuum gasoil (VGO) from the vacuum ﬂasher read more..
drum as in the Tervahl-T process. The gas and oil from the soaking drum efﬂuent aremixed with recycle hydrogen and separated in the hot separator; where the gas iscooled, passed through a separator, and recycled to the heater and soaking drumefﬂuent. The liquids from the hot and cold separator are sent to the stabilizer section,where purge gas and synthetic crude are separated. The gas is used as fuel and thesynthetic crude can now be transported or stored.5.4Process InnovationsPetroleum read more..
5.4.1VisbreakingVisbreaking may be the most under-estimated and/or under-valued process ina reﬁnery. It is not seen as making major comeback in U.S. reﬁneries (Marano, 2003),but this opinion may require some re-evaluation. Originally developed to produce fueloil that met a set of product speciﬁcations, it may in future be used not only for heavyfeedstock processing, (including tar sand bitumen), but also for bio-feedstocks.Visbreaking processes have sufﬁcient hardware ﬂexibility to read more..
bio-feedstock would be a beneﬁt. This can be accomplished by one or two prelimi-nary treatment steps (such as the visbreaking process) in which the feedstock is de-mineralized and the oxygen constituents are removed as overhead (volatile) material.This gives the potential for the production of a fraction rich in oxygen functionalitythat may be of some use to the chemical industry. Such a process might have to beestablished at a bio-feedstock production site, unless the reﬁnery has the means read more..
heater. By moving the zone plate from an operating position to a spalling position, andadjusting the temperature of the plurality of burners, the temperature of the pipes inthe zone of the heater radiant section to be spalled can be lowered, while thetemperature in the remaining zones of the heater radiant section are fully operational.The delayed coking process will remain a preferred residue upgrading optionbecause of its ability to handle the heaviest, contaminated crudes. read more..
both fuel and anode-grade coke feedstocks. Based on crude availability and marketconditions, these coker units will process sour residues for fuel coke production fora speciﬁed time and then switch to run sweet residues to make anode coke.5.4.3Other ProcessesOne of the most promising pathways to simultaneously reducing energy use andcapital costs is process intensiﬁcation. This is a new area of reactor development,aiming at producing more compact reactors to dramatically reduce the size read more..
cellulose devolatilize fairly quickly over a relatively narrow temperature range, thermaldegradation of lignin is a slow process that commences at a lower temperature than thatof cellulose (Bajus, 2010).Fluid coking units will also change over the next decades, although these changesmay be minimal and more focused on internal operation of the units, as well ascoupling of the units with other process units. The process is valuable as it hasgenerally proved to equal or better net realizations from read more..
polynuclear aromatic products. Both of these processes would beneﬁt if a highervalued product could be produced.5.5Relevant PatentsUnited States Patent 7,744,743 June 29, 2010. Process for upgrading tar. McCoy, J.N., Keu-senkothen, P.F., and Srivastava, A.A feed stream comprising tar is fed to a solvent deasphalter wherein it is contacted witha deasphalting solvent or ﬂuid to produce a composition comprising a mixture or slurry ofsolvent containing a soluble portion of the tar, and a heavy read more..
partial visbreaking. The visbroken bottoms may be steam stripped to recover the visbrokenmolecules while avoiding entrainment of the bottoms liquid. An apparatus for carrying out theprocess is also provided.United States Patent 7,578,929 August 25, 2009. Process for steam cracking heavy hydro-carbon feedstocks. Stell, R.C., Dinicolantonio, A.R., Frye, J.M., Spicer, D.B., McCoy, J.N.,and Strack, R.D.A process for feeding or cracking heavy hydrocarbon feedstock containing non-volatilehydrocarbons read more..
Gary, J.H., Handwerk, G.E., Kaiser, M.J., 2007. Petroleum Reﬁning: Technology andEconomics, Fifth ed. CRC Press, Taylor & Francis Group, Boca Raton, Florida.Goetze, L., Bailer. O., 1999. Reactive Distillation with Katapak-S. Sulzer Technical Review.4: 29–31.Haslego, C., 2001. Compact Condensing: New Technology Improves on TraditionalApproach. Hydrocarbon Processing 80, 55–60.Hsu, C.S., Robinson, P.R., 2006. Practical Advances in Petroleum Processing. Springer,New York. Volumes 1 and read more..
Speight, J.G., 2000. The Desulfurization of Heavy Oils and Residua, second ed. MarcelDekker Inc., New York.Speight, J.G., Ozum, B., 2002. Petroleum Reﬁning Processes. Marcel Dekker Inc, New York.Speight, J.G., 2007. The Chemistry and Technology of Petroleum, fourth ed. CRC Press,Taylor & Francis Group, Boca Raton Florida.Speight, J.G., 2008. Synthetic Fuels Handbook: Properties, Processes and Performance.McGraw-Hill, New York.Speight, J.G., 2009. Enhanced Recovery Methods for Heavy Oil and read more..
6 Catalytic Cracking6.1IntroductionCatalytic cracking is a conversion process that can be applied to a variety of feed-stocks from gas oil to heavy oil and residues (Speight and Ozum, 2002; Hsu andRobinson, 2006; Gary et al., 2007; Speight, 2007). The concept of catalytic crackingis basically the same as thermal cracking, but it differs by the use of a catalyst that isnot, in theory, consumed in the process. It is one of several applications used ina reﬁnery that employ a catalyst to improve read more..
3.Use of a short residence time as a means of preparing the feedstock.4.Hydrotreating or mild hydrocracking to prevent excessive coking in the ﬂuid catalyticcracking unit. (Bartholic, 1981a, 1981b; Speight, 2000, 2004; Speight and Ozum,2002; Hsu and Robinson, 2006; Gary et al., 2007; Speight, 2007 and references citedtherein).Hydrotreating the feedstock to the cracker improves the yield and quality of naphtha(Table 6.2) and reduces the sulfur emissions from the unit; but it is typically a read more..
6.2Commercial ProcessesCatalytic cracking is an innovation that truly belongs to the twentieth century. It is themodern method for converting high-boiling petroleum fractions, such as gas oil, intogasoline and other low-boiling fractions. The different processes currently employedin catalytic cracking differ mainly in their method of catalyst handling; although thereis an overlap with regard to catalyst type and the nature of the materials produced. Thecatalyst, which may be an activated natural read more..
Two advances in the technology of moving bed catalytic cracking have greatlychanged way it is operated, in comparison to the early processes. The more importantof these advances was the introduction of crystalline aluminosilicate cracking cata-lysts; but the development of techniques to reduce catalyst attrition and metal erosionin moving bed cracking units has also been useful.In an example of the moving bed process, gas-oil vapor/liquid ﬂows downwardthrough the reactor concurrently with the read more..
When cracking is conducted in a single stage, the more reactive hydrocarbons maybe cracked, with a high conversion to gas and coke in the reaction time necessary forreasonable conversion of the more refractory hydrocarbons. However, in a two-stageprocess, gas and gasoline from a short-reaction-time, high-temperature crackingoperation are separated, before the main cracking reactions take place in a second-stage reactor.6.2.1Fixed-Bed ProcessesHistorically, the Houdry ﬁxed-bed process, which read more..
powdered catalyst that is moved through the reactor (Figure 6.2). The resultant ﬂowpatterns will vary with the precise conﬁguration of the reactor. The catalyst particlesare of such a size that when aerated with air or hydrocarbon vapor, they behave likea liquid and can be made to ﬂow through pipes. Thus, vaporized feedstock andﬂuidized catalyst ﬂow together into a reaction chamber where the catalyst, stilldispersed in the hydrocarbon vapors, forms beds in the reaction chamber and read more..
The model IV low-elevation design was preceded by the model III (1947)balanced-pressure design, the model II (1944) downﬂow design, and the originalmodel I (1941) upﬂow design. The ﬁrst commercial model IV installation in theUnited States came on-stream in 1918.104.22.168.bOrthoﬂow Fluid-Bed Catalytic CrackingThis process uses a unitary vessel design. This provides a straight-line ﬂow ofcatalyst, and thereby minimizes the erosion encountered in pipe bends. CommercialOrthoﬂow designs are read more..
oils into lighter high-quality gasoline and middle distillate fuel oils. Feed preparationmay consist of ﬂashing in a separator to obtain vapor feed. The separator bottoms maybe sent to a vacuum tower from which the liquid feed is produced.The gas oil vapor-liquid ﬂows downward through the reactor concurrently with theregenerated synthetic bead catalyst. The catalyst is purged by steam at the base of thereactor and gravitates into the kiln, or alternatively regeneration is accomplished bythe read more..
entrained material (tar) are left behind. The cracked vapors enter a bubble towerwhere they are separated into two parts; gas oil and pressure distillate. The latter isseparated into gasoline and gases. The spent catalyst is ﬁltered from the organic carry-over, which is used as a heavy industrial fuel oil.The process is actually a compromise between catalytic and thermal cracking. Themain effect of the catalyst is to allow a higher cracking temperature and to assistmechanically in keeping coke read more..
reactions are endothermic, reaction temperature declines from bottom to top. At thetop, the mixture enters a solid-gas separator, and the product vapors are led away.Cracked gases are separated and fractionated; the catalyst and residue, together withrecycle oil from a second-stage fractionator, pass to the main reactor for furthercracking. The products of this second-stage reaction are gas, gasoline and gas oilstreams, and recycle oil.The coked catalyst enters the stripper where steam is added read more..
6.2.4.bProcess ParametersAs already noted, the primary variables related to the operation of ﬂuid catalytic crackingunits for maximum unit conversion for a given feedstock quality can be divided intocatalytic or process variables; the latter including pressure, reaction time and reactortemperature. Higher conversion and coke yield are thermodynamically favored by higherpressure. However, pressure is usually varied over a very narrow range due to limited airblower horsepower. Conversion is not read more..
3.To passivate vanadium and nickel present in many heavy feedstocks.4.To oxidize coke to carbon dioxide.5.To reduce sulfur dioxide emissions.Both vanadium and nickel can deposit on the cracking catalyst, and are extremelydeleterious when present in excess of 3000 ppm. Formulation changes to the catalystcan improve tolerance to these metals; but the use of additives that speciﬁcallypassivate either metal is often preferred.6.2.4.dCokingThe formation of coke deposits has been observed in read more..
are speciﬁc to a given unit conﬁguration, but all serve the same fundamental purposeof reducing undesirable post-riser reactions. There are also many options forpromoting reduced post-riser cracking to improve yields. A combination of higherreactor temperature, higher catalyst to oil ratio, higher feed rate, and/or poorer qualityfeed is typically employed. Catalyst modiﬁcation is also used, and normal catalystcriteria, such as low coke and dry gas selectivity, are of lower importance due read more..
internals have sufﬁciently cooled before air enters the reactor, will eliminate thisproblem. In fact, the only defense against coke plugging problems during start-up is tothoroughly clean the unit during the turnaround and remove all the coke. If strainersare present on the line(s), they will have to be cleaned frequently.Two basic principles for minimizing coking are to avoid dead spots and preventheat losses. An example of the former is in the use of purge steam to sweep outstagnant areas in read more..
synthesized silica-alumina or silica-magnesia preparations. Their ability to yieldessentially the same products may be enhanced to some extent by the incorporation ofsmall amounts of other materials, such as the oxides of zirconium (zirconia, ZrO2),boron (boria, B2O3, which has a tendency to volatilize away on use), and thorium(thoria, ThO2). Both natural and synthetic catalysts can be used as pellets or beads,and also in the form of powder; in either case replacements are necessary because read more..
6.3.2Catalyst VariablesThe variables related to the catalyst that can be changed in the operation of ﬂuidcatalytic cracking units are (1) catalyst activity and (2) catalyst design, the latterincluding availability of cracking sites and the presence of carbon on the regeneratedcatalyst.The equilibrium catalyst activity, as measured by a microactivity test (MAT), isa measure of the availability of zeolite and active matrix cracking sites for conversion.Therefore, an increase in the unit activity read more..
compounds. Increased metal content in the catalyst affects cracking yields byincreasing coke formation, decreasing gasoline and butane and butylene production,and increasing hydrogen production.6.3.3.aDemet ProcessA cracking catalyst is subjected to two pretreatment steps; the ﬁrst effects vanadiumremoval and the second, nickel. The metals on the catalyst go through a chemicalconversion to produce compounds that can be readily removed through water washing(catalyst wash step). The treatment read more..
applications involving the conversion of highly-contaminated residua. This has beencommercially proven on feedstocks ranging from gas oil-residuum blends to atmo-spheric residua, as well as blends of atmospheric and vacuum residua. In addition tohigh gasoline yields, the residuum ﬂuidized catalytic cracking unit also producesgaseous, distillate and fuel oil-range products.The product quality from this process is directly affected by the feedstock quality.In particular, and in contrast to read more..
6.4.2Residue Fluid Catalytic Cracking ProcessThe residue ﬂuid catalytic cracking process (HOC process) is a version of the ﬂuidcatalytic cracking process that has been adapted to conversion of residua whichcontain high amounts of metal and asphaltenes (Finneran, 1974; Murphy and Treese,1979; Johnson, 1982; Feldman et al., 1992).In the process, a residuum is desulfurized and the non-volatile fraction from thehydrodesulfurization unit is charged to the residuum ﬂuid catalytic cracking unit. read more..
Any unconverted feedstock is recycled to the cracker from the bottom of the scrubber.The scrubber efﬂuent is separated into hydrogen gas, liqueﬁed petroleum gas (LPG),and liquid products that can be upgraded by conventional technologies to priorityproducts.In the regenerator, coke deposited on the catalyst is partially burned, to formcarbon monoxide. This is done partly to reduce iron tetroxide formation, and partly toact as a heat supply. In the desulfurizer, sulfur in the solid catalyst is read more..
zone, the feed is injected through a series of nozzles located around the circumferenceof the reactor riser.The catalyst/oil disengaging system is designed to separate the catalyst from thereaction products and then rapidly remove the latter from the reactor vessel. Spentcatalyst from the reaction zone is ﬁrst steam stripped to remove adsorbed hydrocarbon,and then routed to the regenerator. Here, all of the carbonaceous deposits are removedby combustion, restoring the catalyst to an active read more..
6.4.7S&W Fluid Catalytic Cracking ProcessThe S&W FCC process is also designed to maximize the production of distillatesfrom residua (Table 6.4)(Speight and Ozum, 2002; Speight, 2007).In this process, the heavy feedstock is injected into a stabilized, upward ﬂowingcatalyst stream; where the feedstock-steam-catalyst mixture travels up the riser and isseparated by a high efﬁciency inertial separator. The product vapor goes overhead tothe main fractionator.The spent catalyst is read more..
Several process innovations have been introduced in the form of varying processoptions, some using piggy-back techniques, where one process works in closeconjunction with another; whilst there are other options that have not yet beenintroduced or even invented but may well ﬁt into the reﬁnery of the future.In the ﬂuid catalytic cracker (FCC) the major developments have been in theintegration of cracking processes with sulfur removal to produce low-sulfur gasolinewithout octane loss read more..
There are also proposals (some of which have already been put into practice) to by-pass the atmospheric and vacuum distillation units by feeding crude oil directly intoa cracking process; which would provide the ﬂexibility to produce a varying range ofproducts with a net energy saving (Petrick and Pellegrino, 1999).Light cycle oil production from catalytic cracking units will be increased bymodifying feedstock composition, introducing improved catalysts and additives, andmodifying operating read more..
could be lower in cost than petroleum. Secondly, they can reduce the costs ofproducing fuels and chemicals from bio-feedstocks by utilizing existing productionand distribution systems for petroleum-based products; which would remove the needto establish parallel systems. Finally, the use of bio-feedstocks provides a productionbase for fuels and chemicals that is less threatened by changes in government policiestoward fossil fuel feeds and renewable energies.Bio-feedstocks that can be processed read more..
comprises the following steps: a) placing in contact with a zeolite catalyst, in a main riser of theFCCU, a hydrocarbon feedstock A which possesses a level of basic nitrogen at least 200 ppmlower than feedstock B that is being processed in a secondary riser of the FCCU; b) simulta-neously, placing in contact with the zeolite catalyst, in the secondary riser of the FCCU,a hydrocarbon feedstock B comprised of a mixture made up of between 95 and 40%, in volume,of hydrocarbon streams with a content read more..
riser operated at a temperature greater than about 450C to thereby produce a spent catalyst anda third product comprising hydrocarbons; and f) separating the third efﬂuent from the spentcatalyst.United States Patent 7,749,937 July 6 2010. Catalyst composition, its preparation and use.Domokos, L., Jongkind, H., Stork, W.H.J., and Van Den Tol-Kershof, J.M.H.An unsupported catalyst composition which comprises one or more Group VIb metals, one ormore Group VIII metals, and a refractory oxide read more..
Hemler., C.L., 1997. In: Meyers, R.A. (Ed.), Handbook of Petroleum Reﬁning Processes.McGraw-Hill, New York (Chapter 3.3).Hsu, C.S., Robinson, P.R., 2006. Practical Advances in Petroleum Processing. Springer,New York. vols. 1–2.Hunt, D.A., 1997. In: Meyers, R.A. (Ed.), Handbook of Petroleum Reﬁning Processes.McGraw-Hill, New York (Chapter 3.5).Johnson, T.E., Niccum, P.K., 1997. In: Meyers, R.A. (Ed.), Handbook of Petroleum ReﬁningProcesses. McGraw-Hill, New York (Chapter 3.2).Ladwig, read more..
7 Deasphalting and DewaxingProcesses7.1IntroductionSolvent deasphalting is essentially a solvent-based extraction process, and therequired solvent is usually available within the reﬁnery. The process separates oilfrom carbon rich components, resins, and asphaltenes and, makes it possible toconvert it to lube stock, or into feedstock for other secondary processing facilities.Feedstock impurities such as sulfur and metals are concentrated in the insolublephase. The ﬂexibility inherent in the read more..
this wax before further processing. The mechanism of solvent dewaxing involveseither the separation of wax as a solid that crystallizes from solution at lowtemperatures, or the separation of wax as a liquid that is extracted at temperaturesabove its melting point through selectivity of the solvent. The former mechanism isthe usual basis for commercial dewaxing processes.7.2Commercial Deasphalting ProcessesPetroleum processing normally involves separation of a crude oil into various frac-tions, read more..
mainly for use in the aluminum industry, has made delayed coking a much-usedresiduum conversion process. However, many crude oils will not produce coke thatmeets the sulfur and metals speciﬁcations for aluminum electrodes; and coke gas oilsare less desirable feedstocks for ﬂuid catalytic cracking than virgin gas oils. Incomparison, the solvent deasphalting process can be applied to most vacuum residua.The deasphalted oil is an acceptable feedstock for both ﬂuid catalytic cracking, and read more..
downward while the light solvent ﬂows upward. As the extraction progresses, thedesired oil dissolves in the solvent, while the asphalt separates and moves toward thebottom. As the extracted oil and solvent rise in the tower, the temperature is increasedin order to control the quality of the product by providing adequate reﬂux foroptimum separation.Separation of oil from asphalt is controlled by maintaining a temperature gradientacross the extraction tower and by varying the solvent-to-oil read more..
The yield of deasphalted oil varies with the feedstock (Table 7.1) but the deas-phalted oil does make less coke and more distillate than the feedstock. Therefore, theprocess parameters for a deasphalting unit must be selected with care according to thenature of the feedstock and the desired ﬁnal products. The metal, nitrogen and sulfurcontent of the deasphalted oil are also related to its yield (Speight and Ozum, 2002;Speight, 2007). The character of the deasphalting process is a molecular read more..
which allows the removal of these compounds. This results in a drastic reduction(relative to the feedstock) of the nitrogen and metals levels in the deasphalted oil.Although that from propane deasphalting has the best quality, the yield is usually lessthan if a higher molecular weight (higher boiling) solvent is used.The ratios of propane-oil required vary from 6: l to 10:1 by volume, with the ratiooccasionally being as high as 13:1. The critical temperature of propane is 97C(206F), which limits read more..
can be processed. A dual solvent may be the only option that provides the desiredﬂexibility if a deasphalting unit is required to handle a variety of feedstocks, and/orproduce various yields of deasphalted oil. For example, a mixture of propane andn-butane might be suitable for feedstocks from vacuum residua to heavy gas oils.Adjusting the solvent composition allows the most desirable product quantity andquality within the available range of temperatures.In addition to solvent composition, the read more..
The rectifying zone contains some elements designed to promote contacting and toavoid channeling. Steam-heated coils to raise the temperature sufﬁciently to inducean oil-rich reﬂux in the top section of the tower. The stripping zone has disengagingspaces at the top and bottom, and consists of contacting elements between the oil inletand the solvent inlet.A countercurrent tower with static bafﬂes is widely used in solvent deasphaltingunits. The bafﬂes consist of ﬁxed elements, formed of read more..
Both processes generally require tolerant catalysts as well as, in the case of hydro-desulfurization; high hydrogen pressure, low space velocity, and high hydrogenrecycle ratio.For both processes, the advantage of using the deasphalting process to remove thetroublesome compounds becomes obvious. The deasphalted oil, with no asphalteneconstituents and low metal content, is easier to process than the residua. Indeed, in thehydrodesulfurization process, the deasphalted oil may consume only 65% of read more..
7.2.2.aDeep Solvent Deasphalting ProcessThe Deep Solvent Deasphalting process (Table 7.2) is an application of the LEDA(Low Energy Deasphalting) process (RAROP, 1991, p. 91; Hydrocarbon Processing,1998, p. 67) that is used to extract high quality, lubricating oil bright stock, or preparecatalytic cracking feeds, hydrocracking feeds, hydrodesulfurization unit feeds andasphalt from vacuum residue materials. The LEDA process uses a low-boilinghydrocarbon solvent speciﬁcally formulated to ensure read more..
Table 7.3Feedstock and Product Data for the Demex Process.FeedstockVacuumresiduum*Vacuumresiduum*Arabianlight vacuumresiduumArabianlight vacuumresiduumArabianlight vacuumresiduumArabianheavy vacuumresiduumArabianheavy vacuumresiduumAPI22.214.171.124.96.93.03.0Sulfur, wt. %4.04.04.04.04.06.06.0Nitrogen, wt. %0.30.30.30.126.96.36.199Carbon residue, wt %.20.820.820.820.820.827.727.7Nickel, ppm23.023.023.064.064.0Vanadium, ppm75.075.075.0205.0205.0Nickelþ vanadium, ppm98.098.0C6-asphaltenes, wt. read more..
Solvent ﬂows upward, extracting the parafﬁnic hydrocarbons from the vacuumresiduum, which ﬂows downward.Steam coils at the top of the tower maintain a speciﬁed temperature gradient acrossthe rotating disc contactor. The higher temperature in the top section results inseparation of the less soluble; heavier material from the mix and provides internalreﬂux, which improves the separation. The mix leaves the top of the rotating disccontactor tower, then ﬂows to an evaporator where it is read more..
In the process, the vacuum residuum feedstock, mixed with Demex solventrecycling from the second stage, is fed to the ﬁrst stage extractor. The pressure iskept high enough to maintain the solvent in the liquid phase. The temperature iscontrolled by the degree of cooling of the recycle solvent. The solvent rate is setnear the minimum required to ensure that the desired separation occurs. Asphal-tene constituents are rejected in the ﬁrst stage with some resins to maintainsufﬁcient ﬂuidity read more..
of the remainder. Asphalt is then sent to the asphalt stripper, where the ﬁnal portion ofsolvent is completely removed.Solvent recovered from the deasphalted oil and asphalt ﬂash towers is cooled andcondensed into liquid, and sent to a solvent tank. The solvent vapor leaving bothstrippers is cooled to remove water and compressed for condensation. The condensedsolvent is then sent to the solvent tank for further recycling.7.2.2.dResiduum Oil Supercritical Extraction ProcessThe residuum oil read more..
through counter-current ﬂow of solvent, the asphaltene constituents are precipitated,separated, and stripped of solvent by steam. The overhead solution from the ﬁrsttower is taken to a second stage, where it is heated to a higher temperature, thuscausing the resin constituents to separate. The ﬁnal material is taken to a third stageand heated to a supercritical temperature. This makes the oils insoluble and separationoccurs. This process is very ﬂexible and allows precise blending to read more..
The process was developed to give maximum yields of deasphalted oil whileeliminating asphaltenes and reducing metals content to a level compatible with thereliable operation of downstream units (Peries et al., 1995; Hydrocarbon Processing,1996).7.2.2.fOther processesOther facilities incorporate lube deasphalting to process vacuum residuum into lubeoil base stocks. Propane deasphalting is most commonly used to remove asphalteneconstituents and resins, which give the base stocks an undesirable read more..
a series of batch extractors followed by solvent recovery in multistage ﬂash distil-lation and stripping towers.7.3Commercial Dewaxing ProcessesIn the 1930s two types of stocks, naphthenic and parafﬁnic, were used to make motoroils. Both types were solvent-extracted to improve their quality, but in the high-temperature conditions encountered in service, the naphthenic type did not stand up aswell as the parafﬁnic type. Nevertheless, the naphthenic type was the preferred oil,particularly in read more..
and the ﬁlter aid assisted in building a wax cake on the ﬁlter cloth. This process is nowobsolete, and most of the modern dewaxing processes use a mixture of methyl ethylketone and benzene. Other ketones may be substituted, regardless of which is used,the process is generally known as ketone dewaxing.The process involves mixing the feedstock with one to four times its own volumeof the ketone (Figure 7.4)(Scholten, 1992). The mixture is then heated until the oil isdissolved, and the solution read more..
Ketone is removed from both components by distillation, but before the wax isdistilled, it is de-oiled, mixed with more cold ketone, and pumped to a pair of rotaryﬁlters in series, where further washing with cold ketone produces a wax cake thatcontains very little oil. This de-oiled wax is melted in heat exchangers and pumped toa distillation tower operated under vacuum, where a large part of the remaining ketoneis evaporated or ﬂashed from it. The ﬁnal portion of the ketone is removed by read more..
then ﬁltered using rotary vacuum ﬁlters and the wax cake is washed with cold solvent.The ﬁltrate is used to pre-chill the feedstock and solvent mixture. The primary waxcake is diluted with additional solvent and ﬁltered again to reduce the oil content ofthe wax. The solvent recovered from the dewaxed oil and wax cake by ﬂash vapor-ization and recycled back into the process.The Texaco Solvent Dewaxing process, also called the MEK process, usesa mixture of MEK and toluene as the dewaxing read more..
The petrolatum layer is also distilled to remove naphtha and may be clay treated oracid and clay treated to improve the color.7.3.4Centrifuge Dewaxing ProcessAnother method of separating petrolatum from reduced crude is centrifuge dewaxing.In this process the reduced crude is dissolved in naphtha and chilled toÀ18C(0F)or lower, which causes the wax to separate. The mixture is then fed to a battery ofcentrifuges where the wax is separated from the liquid. However, the centrifugemethod has now read more..
time allowed between reactivation is a function of the feedstock, and after numerousreactivations it is possible that there will be coke buildup on the catalyst. The processcan be used to dewax a full range of lubricating base stocks, and as such, has thepotential to completely replace solvent dewaxing. Alternatively, use in combinationwith existing solvent dewaxing units would serve to de-bottleneck these facilities.Both these catalytic dewaxing processes provide viable alternatives to the read more..
Isodewaxing and hydroﬁnishing units are selective for dewaxing and hydrogenation.They work at their maximum efﬁciency with low sulfur and low nitrogen feedstocks.The process generally uses a high pressure recycle loop. Because of the conversion ofwax constituents to other usable products, the process has obvious beneﬁts oversolvent dewaxing because the quality of the product is increased.7.4Process InnovationsThe current global petroleum market will continue to offer opportunities for read more..
7.4.1DeasphaltingThe solvent deasphalting process has been operated in reﬁneries for several decades,usually as a piggy-back to other process or; more accurately, as a pre-processing stepas a means of removing heteroatoms and metals (Figure 7.6) before application ofﬂuid coking or ﬂuid catalytic cracking.It is a unique separation process in which residue is separated by molecular type,instead of by boiling point as in vacuum distillation. The UOP/FW solventdeasphalting process produces a read more..
Propane has been used extensively in the preparation of high quality lubricatingoils. Its use has necessitated elaborate solvent cooling systems utilizing cold water,which is a relatively expensive cooling agent. In order to circumvent this need, futureunits will use solvent systems that will allow operation at relatively elevatedtemperatures, thereby permitting easy heat exchange. In addition, it may be founddesirable to integrate dewaxing and deasphalting operations by having a commonsolvent read more..
to selectively enhance or retard the transport of a species across a membrane. Acombined-effect membrane could be constructed with both sufﬁcient strength topermit the application of a signiﬁcant pressure ﬁeld and ionic transport capability.Electrode material could be applied to either side of the membrane. The advantage ofelectrochemical separation methods is that they are able to efﬁciently remove themost polar constituents under controlled conditions.On the other hand, thermal methods read more..
cold solvents from lube oil in the solvent dewaxing process. A membrane process canalso be used to prevent hold-ups in the refrigeration and recovery sections of a solventlube plant. Recovering cold solvent directly from the ﬁltrate, so reducing the amountsubjected to heating and cooling will result in energy savings. However, themembrane will require a high ﬂux, must be robust and able to withstand continuousservice.With the use of microwave technology steadily growing in industrial read more..
Dunning, H.N., Moore, J.W., 1957. Propane Removes Asphalts from Crudes. PetroleumReﬁner 36 (5), 247–250.Gary, J.H., Handwerk, G.E., 2001. Petroleum Reﬁning: Technology and Economics, fourth ed.Marcel Dekker Inc., New York.Gearhart, J.A., 1980. Hydrocarbon Processing 59 (5), 150.Gearhart, J.A., Gatwin, L., 1976. ROSE Process Improves Resid Feed. Hydrocarbon Pro-cessing. May. Page 125–128.Genis, O., 1997. In: Meyers, R.A. (Ed.), Handbook of Petroleum Reﬁning Processes.McGraw-Hill, New read more..
8 Hydrotreating and Desulfurization8.1IntroductionCatalytic hydrotreating, also referred to as hydroprocessing or hydrodesulfurization,commonly occurs at multiple locations in a reﬁnery (Bland and Davidson, 1967;Meyers, 1997; Speight, 2000; Speight and Ozum, 2002; Hsu and Robinson, 2006;Gary et al., 2007; Speight, 2007). It is a catalytic reﬁning process widely used toremove sulfur, unsaturated hydrocarbons and nitrogen from petroleum products suchas naphtha, gasoline, diesel fuel, kerosene, read more..
coke-forming reactions and enhances the yields of the lower boiling components,such as gasoline, kerosene, and jet fuel.Hydrogenation processes for the conversion of petroleum fractions and petroleumproducts may be classiﬁed as destructive or nondestructive.Destructive hydrogenation (hydrogenolysis or hydrocracking) (Chapter 9) ischaracterized by the cleavage of carbon-carbon linkages, accompanied by saturationof the fragments to produce lower boiling products. These reactions require read more..
The major differences between hydrotreating and hydrocracking are the time atwhich the feedstock remains at reaction temperature, and the extent of decompositionof the non-heteroatomic constituents. The upper limits of hydrotreating conditionsmay overlap with the lower limits of hydrocracking; but where the reaction conditionsdo overlap, the feedstocks to be hydrotreated will generally be exposed to the reactortemperature for shorter periods.A growing dependence on high-heteroatom heavy oils and read more..
required speciﬁcations. However, residua, heavy crude oil, and tar sand bitumen posedifﬁculties because they tend to form coke and to shorten catalyst life (Speight, 2000;Ancheyta and Speight, 2007).8.2Rationale for HydroprocessingThere is an approximate correlation between the quality of petroleum products andtheir hydrogen content (Dolbear, 1998). Desirable aviation gasoline, kerosene, dieselfuel, and lubricating oil are made up of hydrocarbons that contain high proportions ofhydrogen. It read more..
present in petroleum, but now have shorter alkyl side-chains. Thus, in addition tooleﬁns, product streams will contain a range of aromatic compounds that need to beremoved to enable many of the product streams to meet product speciﬁcations.Polycyclic aromatics are partially hydrogenated before cracking of the aromaticnucleus takes place. Sulfur and nitrogen are converted to hydrogen sulﬁde andammonia; but a more important role of the hydrogenation is probably to hydrogenatethe potential read more..
mixture is led over a catalyst bed of metal oxides (most often cobalt or molybdenumoxides on different metal carriers). The catalysts help the hydrogen to react withsulfur and nitrogen to form hydrogen sulﬁdes (H2S) and ammonia. The reactorefﬂuent is then cooled, and the oil feed and gas mixture is then separated in a strippercolumn. Part of the stripped gas may be recycled to the reactor.The recycle gas scheme is used in the hydrodesulfurization process to minimizephysical losses of read more..
nature of the feedstock. For example, decalin (decahydronaphthalene) cracks morereadily than the corresponding parafﬁn analog, n-decane, [CH3(CH2)8CH3]togivehigher iso-parafﬁn to n-parafﬁn product ratios than those obtained from the parafﬁn.A large yield of single-ring naphthenes is also produced; these are resistant to furtherhydrocracking, and contain a higher than equilibrium ratio of methylcyclopentane tocyclohexane.One of the issues that arises when hydroprocessing residua is the read more..
required. After leaving the reactor, excess hydrogen is separated from the treatedproduct and recycled through the reactor after removal of hydrogen sulﬁde. The liquidproduct is passed into a stripping tower, where steam removes dissolved hydrogen andhydrogen sulﬁde. After cooling the product is run to ﬁnished product storage or, in thecase of feedstock preparation, pumped to the next processing unit.Excessive contact time and/or temperature will create coking. Precautions need tobe taken read more..
feedstocks. Although the visbreaking process (Chapter 2 and Chapter 5) reduces theviscosity of residua and partially converts them to lighter hydrocarbons and coke; theprocess can also be used to remove the undesirable higher molecular weight polarconstituents. The solvent deasphalting process (Chapter 7) separates the higher valueliquid product (DAO) from low value, asphaltene-rich, pitch stream, by using a lightparafﬁnic solvent. Various residuum hydrotreating (in fact, hydrocracking) read more..
Lubeoil hydrotreating uses catalytic treatment of the oil with hydrogen to improveproduct quality. The oleﬁns are saturated to improve the color, odor, and acid natureof the oil. Mild lube hydrotreating may also be used after solvent processing.Operating temperatures are usually below 315C (600F) and operating pressuresbelow 800 psi. Severe lube hydrotreating, at temperatures in the 315 to 400C (600to 750F) range and hydrogen pressures up to 3,000 psi, is capable of saturatingaromatic rings, read more..
include saturation of oleﬁns and improvements in color, odor, and acid nature of the oil.Mild lube hydrotreating also may be used following solvent processing.8.4Process ParametersThe principal variables affecting the required severity in distillate desulfurization are:1.Hydrogen partial pressure.2.Space velocity.3.Reaction temperature.4.Feedstock properties.8.4.1Hydrogen Partial PressureUse of a high hydrogen partial pressure minimizes coking reactions. If the hydrogenpressure is too low for read more..
The hydrodesulfurization of low-boiling distillate (naphtha or kerosene) is one ofthe more commonly used processes, before deep hydrodesulfurization or catalyticreforming (Datsevitch et al., 2003). This is similar to the concept of pretreatingresidua prior to hydrocracking to improve the quality of the products (Chapter 9).Hydrodesulfurization of such feedstocks is required because sulfur compoundspoison the precious-metal catalysts used in reforming. Desulfurization can be ach-ieved under read more..
slightly more severe reaction conditions, leading to a designated degree of hydro-cracking, also cause an overall increase in hydrogen consumption.High-boiling distillates, such as the atmospheric and vacuum gas oils, are notusually produced as a reﬁnery product; but merely serve as feedstocks to otherprocesses that convert them to lower-boiling materials. For example, gas oils can bedesulfurized to remove more than 80% of the sulfur originally present, with someconversion to lower-boiling read more..
complete charge. In the case of very high metal content feedstocks (such as residua),it is often necessary to replace the entire catalyst charge rather than to regenerate it.This is due to the fact that the metal contaminants cannot be removed by economicalmeans during rapid regeneration and the metals have been reported to interfere withthe combustion of carbon and sulfur, catalyzing the conversion of sulfur dioxide(SO2) to sulfate (SO42À) that has a permanent poisoning effect on the read more..
catalyst particles of each age group are so well dispersed in the reactor that itscontents appear uniform.In the unit, the feedstock and hydrogen recycle gas enter the bottom of the reactor,pass up through the expanded catalyst bed, and leave from the top. Commercialexpanded-bed reactors normally operate with 1/32 inch (0.8 mm) extrudate catalyststhat provide a higher rate of desulfurization than the larger particles used in ﬁxed-bedreactors. With particles of this size, the upward velocity of read more..
former can be added continuously without taking the reactor out of service. The spentdemetallization catalyst can contain more than 30% vanadium, which makes ita valuable source of this expensive metal.8.6Commercial ProcessesHydrotreating technology is one of the most commonly used reﬁnery processes. It isdesigned to remove contaminants such as sulfur, nitrogen, condensed ring aromatics,and/or metals. The feedstocks used in the process range from naphtha to vacuumresidua; and the products in read more..
The processing equipment is similar to that used in hydroﬁning (see below). Thecatalyst is cobalt oxide and molybdenum oxide on alumina, and operating conditionsare usually 340 to 425C (650 to 800F) at pressures of 100 to 200 psi. Hydrogenformed by dehydrogenation of naphthenes in the reactor is separated from the treatedoil and is then recycled through the reactor. The catalyst is regenerated with steam andair at 200 to 1000 hr intervals, depending on whether light or heavy feedstocks read more..
The ﬁrst hydrodesulfurization unit went on stream in January 1970 at the MizushimaReﬁnery of Nippon Mining Company.8.6.4Hydroﬁning ProcessHydroﬁning is a process used for reducing the sulfur content of feedstocks by treatingthe feedstock in the presence of a catalyst. This process can be applied to lubricatingoil, naphtha, and gas oil.The feedstock is heated in a furnace, and passed with hydrogen through a reactorcontaining a suitable metal oxide catalyst, such as cobalt and molybdenum read more..
conﬁguration, the reactor feedstock is typically brought to reaction temperature bya combination of heat exchange with the hot hydroﬁnished product and furnacepreheater. The ﬁxed-bed reactor contains a hydroﬁnishing catalyst and once-through orrecycle hydrogen treat gas may be used. The reactor efﬂuent is ﬂashed to recover theunreacted hydrogen treat gas at high pressure as well as to separate the hydrogensulﬁde and ammonia resulting from the hydroﬁnishing reactions. The read more..
8.6.5Isomax ProcessThe Isomax process is a two-stage, ﬁxed-bed catalyst system that operates underhydrogen pressures from 500 to 1500 psi in a temperature range of 205 to 370C(400 to 700F), with middle distillate feedstocks. The high temperatures and pres-sures mean that the sulfur content of the Isomax product is low.Exact conditions depend on the feedstock and product requirements, and hydrogenconsumption is of the order of 1000 to 1600 ft3 bblÀ1 of feed processed. Each stagehas a separate read more..
aromatics in diesel and to improve the cetane number. In addition, the process can beused to prepare naphtha for catalytic reformers and to reﬁne coker-naphtha (Speightand Ozum, 2002; Speight, 2007).In the process (Figure 8.5), the reactor feed is heat-exchanged with the efﬂuent andinlet temperature being controlled by charge heater ﬁring. As the reaction isexothermic, especially when feedstocks are unsaturated, quench sections may be usedto cool the reaction ﬂuids; and at the same time read more..
The ease of processing a feedstock depends on the nature of the asphaltenes andthe distribution of contaminants throughout the resin and asphaltene fractions.Consequently, the process operates over a large range of operating conditions: 1,500to 3,000 psi and 0.10–1.0 LHSV. Feedstocks with high contaminants, such as vacuumresidues, typically require higher pressures and lower space velocities.8.7Process Options for Heavy FeedstocksThe major goal of residuum hydroconversion is the cracking of read more..
asphaltene conversion. The residuum hydroconversion process produces kerosene,gas oil, and feedstocks for hydrocracking, ﬂuid catalytic cracking, and petrochemicalapplications.The RDS/VRDS process is (like the Residﬁning process) a hydrotreating processthat is designed to hydrotreat vacuum gas oil, atmospheric residuum, or vacuumresiduum to remove sulfur and metallic constituents; while part of the feedstock isconverted to lower-boiling products. In the case of residua, the asphaltene read more..
and facilities to upgrade the off-gases to maintain higher concentration of hydrogen inthe recycle gas. Most of the processes utilize downﬂow operation over ﬁxed-bedcatalyst systems; but exceptions to this are the H-Oil and LC-Fining processes, whichare predominantly conversion processes, that employ upﬂow designs and ebulliatingcatalyst systems with continuous catalyst removal capability; and the Shell Process,a conversion process, that may involve the use of a bunker ﬂow reactor ahead read more..
alumina (200 to 300 m2/g) and the metals are dispersed in a thin layer over the entirealumina surface within the pores (Table 8.3); hence this type of catalyst has a hugecatalytic surface for a given weight. Cobalt (Co), molybdenum (Mo), and nickel (Ni)are the most commonly used metals. The catalysts are manufactured with the metalsin an oxide state. In the active form they are in the sulﬁde state, which is obtained bysulﬁding the catalyst either prior to use or with the feed during actual read more..
8.8.2Catalyst LifeCatalyst life depends on the charge stock properties and the degree of desulfur-ization desired. The only permanent poisons to the catalyst are metals in thefeedstock that deposit on the catalyst, usually quantitatively, causing permanentdeactivation as they accumulate. However, this is usually of little concern exceptwhen deasphalted oils are used as feedstocks, as most distillate feedstocks containlow amounts of metals. Nitrogen compounds are a temporary poison to the read more..
3.On process development.4.On cobalt-molybdenum (Co-Mo) catalysts, nickel-molybdenum catalysts (Ni-Mo), ornickel-tungsten (Ni-W) catalysts supported on alumina, often doped by ﬂuorine orphosphorus.Hydrodesulfurization and demetallization occur simultaneously on the active siteswithin the catalyst pore structure. Sulfur and nitrogen occurring in residua are con-verted to hydrogen sulﬁde and ammonia in the catalytic reactor and these gases arescrubbed out of the reactor efﬂuent gas stream. read more..
The hydrotreating processes are chemically very simple, since they essentiallyinvolve removal of sulfur and nitrogen as hydrogen sulﬁde and ammonia,respectively:RSR1þ H2/RH þ R1Hþ H2SReNðR1ÞeR11 þ 3H2/RH þ R1Hþ R11Hþ 2NH3However, since nitrogen is the most difﬁcult contaminant to remove from feedstocks,the processing conditions are usually dictated by the requirements for its removal.In general, any catalyst capable of participating in hydrogenation reactions may beused for read more..
5.Process design and hardware that are more specialized and focus on process schemes thateffectively reduce hydrogen consumption.Finally, hydrotreating of residua requires different catalysts and process ﬂows, toensure efﬁcient hydroconversion through uniform distribution of liquid, hydrogen-rich gas, and catalyst across the reactor. There will also be automated demetallizationof ﬁxed-bed systems as well as more units that operate as ebullating-bed hydro-crackers (Chapter 9).Finally, read more..
The hydrotreating of feedstocks prior to sending them to a ﬂuid catalytic crackingunit is another important focus. Many ﬂuid catalytic cracking units incorporate pre-treaters to meet their naphtha-gasoline sulfur requirements. Installation of suchreactors units will necessarily increase as high-boiling feedstocks are incorporatedinto gas oils (fed to the ﬂuid catalytic cracking unit), or become the sole feedstock forthe catalytic cracking unit. Proven technology is available to remove read more..
proportion of residua present. These factors require crude oil to be processed moreseverely to produce gasoline and other transportation fuels. Thus, many reﬁneries nowconﬁgured for maximum gasoline production also process highly aromatic distillatebyproducts, such as light cycle oil, to supply the additional feedstock necessary toproduce more distillate.Microbial technology can be exploited in oil reservoirs to improve oil recovery(Speight, 2007 and references cited therein). In such read more..
vanadium from petroleum distillate fractions, coal-derived liquid shale, bitumen, andsynthetic fuels (Van Hamme, 1998 and references cited therein). However, furtherinvestigation of the biochemical mechanisms and bioprocessing issues involved inpetroleum upgrading are required in order to develop reliable biological processes.For upgrading options, the use of microbes has yet to show a competitiveadvantage over the tried-and-true chemical methods prevalent in the industry.Currently, the range of read more..
The disulﬁdes can subsequently be extracted and removed in what is referred to asextractive sweetening.In the hydrotreating process, the feed is reacted with hydrogen in the presence ofa solid catalyst. The hydrogen removes sulfur by conversion to hydrogen sulﬁde,which is subsequently separated and removed from the reacted stream. However,alternatives to this approach exist, and are reviewed here.One new technology is the use of adsorption by metal oxides in which the oxidesreact either by read more..
which bio-feedstocks can be (or will be) incorporated into existing hydrotreating unitsbased on process efﬁciency as well as economic considerations.8.10Relevant PatentsUnited States Patent 7,763,218 July 27 2010. Partial conversion hydrocracking process andapparatus. Hunter, M.G., Vivas, A.H., Jensen, L.S., and, Low, G.G.Partial conversion hydrocracking process comprising the steps of (a) hydrotreating a hydro-carbon feedstock with a hydrogen-rich gas to produce a hydrotreated efﬂuent read more..
a deasphalted oil fraction 118 essentially free of asphaltenes, a water fraction 112, and a solventfraction 114. The process allows removal of salts from the heavy oils and bitumens either intothe aqueous products or with the asphaltene product.United States Patent 7,749,375 July 6 2010. Hydrodesulfurization process. Kokayeff, P., andLeonard, L.E.In one aspect, a hydrodesulfurization process is provided that can selectively desulfurizea hydrocarbon stream with minimal oleﬁn saturation and read more..
Bridge, A.G., 1997. In: Meyers, R.A. (Ed.), Handbook of Petroleum Reﬁning Processes.McGraw-Hill, New York (Chapter 14.1).Carlson, C.S., Langer, A.W., Stewart, J., Hill, R.M., 1958. Ind. Eng. Chem. 50, 1067.Celestinos., J.A., Zermeno, R.G., Van Dreisen, R.P., Wysocki, E.D., 1975. Oil Gas J. 73 (48),127.Chang, J.H., Rhee, S.K., Chang, Y.K., Chang, H.N., 1998. Biotechnol. Prog. 14 (6), 851–855.Chianelli, R.R., Berhault, G., Raybaud, P., Kasztelan, S., Hafner, J., Toulhoat, H., 2002.Periodic read more..
Reynolds, J.G., Beret, S., 1989. Fuel Science and Technology International 7, 165.Scott, J.W., Bridge, A.G., 1971. In: McGrath, H.G., Charles, M.E. (Eds.), Origin and Reﬁningof Petroleum. Advances in Chemistry Series 103. American Chemical Society,Washington, DC, p. 113.Setti, L., Farinelli, P., Di Martino, S., Frassinetti, S., Lanzarini, G., Pifferia, P.G., 1999. Appl.Microbiol. Biotechnol. 52, 111–117.Speight, J.G., Moschopedis, S.E., 1979. The production of low-sulfur liquids and coke read more..
9 Hydrocracking9.1IntroductionHydrocracking is a reﬁning technology that falls under the general umbrella ofhydroprocessing. The other technology, hydrotreating (Chapter 8), is also calledhydrodesulfurization (HDS); and is a catalytic reﬁning process widely used to removesulfur as well as other unwanted compounds from petroleum products such asnaphtha, gasoline, diesel fuel, kerosene, and fuel oil (Bland and Davidson, 1967;Meyers, 1997; Speight, 2000; Speight and Ozum, 2002; Hsu and read more..
prevents adsorption of oleﬁns onto the catalyst, and by preventing their dehydroge-nation, which ultimately leads to coke formation, long on-stream times can beobtained without the need for catalyst regeneration.One of the most important reactions in hydrocracking is the partial hydrogenationof polycyclic aromatics, followed by rupture of the saturated rings to form substitutedFigure 9.1Temperature and Pressure Parameters for Various Processes.Source: Speight. J.G. 2007. The Chemistry and read more..
monocyclic aromatics. The side chains may then be split off to give iso-parafﬁns. Sidechains of three or four carbon atoms are easily removed from an aromatic ring duringcatalytic cracking, but the reaction pathways of aromatic rings that have shorter sidechains appears to be quite different. For example, hydrocracking single-ringaromatics containing four or more methyl groups produces largely iso-butane andbenzene. It may be that successive isomerization of the feed molecule adsorbed on read more..
the ﬁrst stage may actually be a puriﬁcation step to remove sulfur-containing, as wellas nitrogen-containing, organic materials. In terms of sulfur removal, it appears thatnon-asphaltene sulfur may be removed before the more refractory sulfur in asphalteneconstituents (Speight, 2007). This is a good reason for processes to use an extinction-recycling technique to maximize desulfurization and the yields of the desired product.Signiﬁcant conversion of heavy feedstocks can be accomplished by read more..
9.2.1Process DesignAll hydrocracking processes are catalytic operations under relatively high hydrogenpressure, where a heavy oil fraction is treated to give products of lower molecularweight. Many hydrocracking units use ﬁxed beds of catalyst with downﬂow ofreactants. However for heavier feedstocks, the H-Oil process and the LC-Finingprocesses employ an ebullient bed reactor in which the beds of particulate catalyst aremaintained in an ebullient or ﬂuidized condition with up-ﬂowing read more..
material, with low nitrogen content and free of ammonia, is taken as a bottom streamfrom the fractionation section. After heat exchange with reactor efﬂuent, and mixingwith heated recycle gas, it is sent to the second reactor. Here most of the hydro-cracking reactions occur. A strongly acidic catalyst with a relatively low hydroge-nation activity (metal sulﬁdes on, for example, amorphous silica-alumina) is usuallyapplied.As in the ﬁrst reactor, the exothermic nature of the process is read more..
products have been ﬂashed off in a low-pressure separator. The hydrogen-rich gasstream from the high-pressure separator is recycled back to the reactor feed by usinga recycle compressor. Sometimes with sour feeds, the ﬁrst-stage recycle gas isscrubbed using an amine system to remove hydrogen. If the feed sulfur level is high,this option can improve the performance of the catalyst and result in less costlymaterials of construction.The distillation section consists of a hydrogen sulﬁde (H2S) read more..
they can be cracked. Some properties of the products also depend on hydrogenuptake, such as jet fuel aromatics content, smoke point and diesel cetane number. Ingeneral, the higher the feed endpoint, the higher the required hydrogen partial pres-sure necessary to achieve satisfactory performance of the plant.Once-through partial conversion hydrocracking of a given feedstock may becarried out at hydrogen partial pressures signiﬁcantly lower than required for recycletotal conversion read more..
9.3.1Catalyst TypeHydrocracking catalysts typically contain separate hydrogenation and crackingfunctions. Palladium sulﬁde and promoted group VI sulﬁdes, nickel molybdenum ornickel tungsten, provide the hydrogenation function. These active compositionssaturate the aromatics that are present in the feed, as well as any oleﬁns that areformed in the cracking; and they also protect the catalysts from poisoning by coke.Zeolites or amorphous silica-alumina provide the cracking functions. They read more..
Catalyst operating temperature can inﬂuence reaction selectivity, since the acti-vation energy for hydrotreating reactions is much lower than for hydrocracking.Raising the temperature in a residuum hydrotreater therefore increases the extent ofhydrocracking relative to hydrotreating, which also increases the hydrogen con-sumption (Bridge et al., 1975, 1981).The cracking reaction results from the attack of a strong acid on a parafﬁn chain toform a carbonium ion, a carbon cation, e.g., read more..
Al/Si atoms, which are joined together through oxygen atoms. The zeolite structure isgenerated by joining sodalite cages together via four Si/Al rings, enclosing a cavity,or super cage, bounded by a cube of eight sodalite cages and readily accessiblethrough the faces of that cube (channels or pores). Joining sodalite cages togetherthrough the six Si/Al faces generates the structural frameworks of faujasite, zeolite X,and zeolite Y. In zeolites, the effective width of the pores is usually read more..
zeolite in the catalysts, with the remainder being the hydrogenation component anda silica (SiO2) or alumina (Al2O3) binder. Exact recipes are guarded as trade secrets.Crystalline zeolite compounds provide a broad family of solid acid catalysts. Thechemistry and structures of these solids are beyond the scope of this book. What isimportant here is that the zeolites are not acidic when they are crystallized. They mustbe converted to acidic forms by ion exchange processes. The chemistry of the read more..
particularly worthy of mention since they have shown up to 200 times greater activityfor hexane cracking in the temperature range 360 to 400C (680 to 750F).Other zeolite catalysts are also remarkably useful in the reﬁning industry. Forexample, resistance to deactivation of the type Y zeolite catalysts containing eithernoble or non-noble metals is remarkable, and catalyst life of up to 7 years has beenobtained commercially in processing heavy gas oils in the Unicracking-JHC process.Operating read more..
and Clausen, 1984; Ho, 1988). The catalyst base, such as acid-treated clay, usuallysupplies the cracking function, and the hydrogenation function is supplied by metals,such as nickel, tungsten, platinum, or palladium. These highly acidic catalysts arevery sensitive to nitrogen compounds in the feed, that break down to give ammonia,which in turn neutralizes the acid sites. As many heavy gas oils contain substantialamounts of nitrogen (up to approximately 2500 ppm) a puriﬁcation stage is read more..
surface. There is, however, a slow accumulation of coke that reduces activity overa 1 to 2 year period. Reﬁners respond to this slow reduction in activity by raising theaverage temperature of the catalyst bed to maintain conversion. Eventually, however,an upper limit to the allowable temperature is reached and the catalyst must beremoved and regenerated.Catalysts carrying coke deposits can be regenerated by burning off the accumu-lated coke. This is done by service in rotary or similar kilns, read more..
3.Product quality (speciﬁcations) required.4.The need to integrate the new facilities in a logical and cost-effective way with any existingfacilities.9.3.8Extensions of the ProcessAs illustrated above for various forms of more conventional hydrocracking, the typeof catalyst used can inﬂuence the product slate obtained. For example, for a mildhydrocracking operation at constant temperature, the selectivity of the catalyst variesfrom about 65% to about 90% by volume. Indeed, several catalytic read more..
9.4Process Options for Heavy FeedstocksThe major goal of residuum hydroconversion is cracking of residua with desulfur-ization, metal removal, denitrogenation, and asphaltene conversion. Residuumhydroconversion process offers production of kerosene and gas oil, feedstocks forhydrocracking, ﬂuid catalytic cracking, and petrochemical applications. Theprocesses that follow are listed in alphabetical order with no other preference in mind.In addition to those listed below, residﬁning can also be read more..
hydrodesulfurization as well as having sufﬁcient resistance to coke fouling and metaldeposition when using such feedstocks as vacuum or thermally cracked residua,solvent deasphalted bottoms, or bitumen, with ﬁxed catalyst beds (Takeuchi, 1982).The process can be combined with:1.Solvent deasphalting for complete or partial conversion of the residuum.2.Hydrodesulfurization to promote the conversion of residue, to treat feedstock with highmetals and to increase catalyst life.3.Hydrovisbreaking read more..
hydrocarbon phase, through which the hydrogen and product gases ﬂow rapidly inbubble form. The reactor exit stream is quenched with cold recycle hydrogen prior tothe high-pressure separator. The heavy liquids are further reduced in pressure in a hotmedium pressure separator, and pass from there to fractionation. The spent additiveleaves with the heavy fraction and remains in the unconverted vacuum residue.The vapor stream from the hot, high-pressure separator is cooled stepwise toproduce read more..
The process also offers the attractive option of reducing the coke yield by slurryingthe feedstock with less than 10 ppm of catalyst (molybdenum naphthenate), andsending the slurry to a hydroconversion zone to produce low-boiling products (Krizand Ternan, 1994).9.4.3H-Oil ProcessThe H-Oil process (Speight and Ozum, 2002; Speight, 2007) is a catalytic process thatthat uses a single-stage, two-stage, or three-stage ebullated-bed reactor in which,during the reaction, considerable hydrocracking read more..
bed (Kressmann et al., 2000). The heat of reaction is used to bring the feed oil andhydrogen up to reactor temperature.In the process, the feedstock (a vacuum residuum) is mixed with recycle,hydrogen-rich recycle gas, and fresh hydrogen. This combined stream is fed into thebottom of the reactor whereby the upward ﬂow expands the catalyst bed. The mixedvapor and liquid efﬂuent from the reactor either goes to the ﬂash drum for phaseseparation, or to the next reactor. A portion of the read more..
minimized and ﬁne solids entrained in the feed do not lead to reactor plugging. Thecatalyst can also be added and withdrawn from the reactor without interrupting thecontinuity of the process. The reactor efﬂuent is cooled by exchange and separated intovapor and liquid. After scrubbing in a lean oil absorber, the hydrogen is recycled, andthe liquid product is either stored directly, or fractionated before storage and blending.H-Oil and LC-ﬁning technologies are often practiced commercially read more..
put on standby while the rest of the unit continues to operate. More that 50% of themetals are removed from the feed in the guard reactors.In the process, the pre-heated feedstock enters one of the two guard reactors, wherea large proportion of the nickel and vanadium are adsorbed and hydroconversion ofthe high molecular weight constituents commences. Meanwhile, the second guardreactor catalyst undergoes a reconditioning process and is then put on standby. Fromthe guard reactors, the feedstock read more..
fraction is recycled; or all of it is drawn as heavy product, depending on whether thelow-boiling or high-boiling products are of greater value. If the low-boiling distillateproducts (naphtha or naphtha/kerosene) are the most valuable, the higher boilingpoint distillates (like diesel) can be recycled to the reactor for conversion ratherthan drawn as a product (RAROP, 1991, p. 83). Product distribution depends upon themode of operation.Heavy feedstocks have been used in the process and the read more..
catalyst (Speight, 2007). Reactor products ﬂow to the high pressure/high temper-ature separator. Vapor efﬂuent from the separator is reduced in pressure, and thengoes to the heat exchanger, and thence to a section for the removal of condensableproducts, followed by puriﬁcation (Table 9.4)(Speight and Ozum, 2002;Speight, 2007).Liquid is let down in pressure and passes to the recycle stripper. This is a mostimportant part of the high conversion process. The liquid recycle is prepared to read more..
continuously. Low pressure drops and isothermal operating conditions result from theexpanded bed operating mode. Extruded catalyst particles as small as 0.8 mm (1/32inch) in diameter can be used in this reactor.Although the process may not achieve direct conversion of bitumen to a syntheticcrude oil, it does nevertheless offer an attractive means of bitumen conversion. Itcould, however, be the primary conversion process from which liquid products wouldaccrue; these products would then pass to a read more..
9.4.11Mild Hydrocracking ProcessThe mild hydrocracking process uses operating conditions that are similar to those ofa vacuum gas oil (VGO) desulfurizer, for conversion of vacuum gas oil to signiﬁcantyields of lighter products. Consequently, the ﬂow scheme for a mild hydrocrackingunit is virtually identical to that of a vacuum gas oil desulfurizer.For example, in a simpliﬁed process for vacuum gas oil desulfurization, the vacuumgas oil feedstock is mixed with hydrogen make-up gas and read more..
bitumen, and to produce mainly middle distillates (Sue, 1989; RAROP, 1991, p. 65;Speight and Ozum, 2002; Speight, 2007). The reactor is designed to maintain a mixedthree-phase slurry of feedstock, ﬁne powder catalyst and hydrogen, and to promoteeffective contact.In the process, a slurry consisting of heavy oil feedstock and ﬁne powder catalyst ispreheated in a furnace and fed into the reactor vessel. Hydrogen is introduced fromthe bottom of the reactor and ﬂows upward through the reaction read more..
The reactors are of multi-bed design with inter-bed cooling and the multi-catalyst system can be tailored according to the nature of the feedstock and thetarget conversion. For residua with high metals content, a hydrodemetallizationcatalyst is used in the front-end reactor(s), which excels in its high metal uptakecapacity and good activities for metal removal, asphaltene conversion, and residuecracking. Downstream of the demetallization stage, one or more hydroconversionstages, with optimized read more..
sulfur content of the feedstock as is catalyst life, product sulfur, and hydrogenconsumption (Speight, 2000 and references cited therein).In a the process, the feedstock and hydrogen-rich recycle gas are preheated, mixed,and introduced into a guard reactor that contains a relatively small quantity of thecatalyst. The guard chamber removes particulate matter and residual salt from thefeed. The efﬂuent from the guard chamber ﬂows down through the main reactor,where it contacts one or more read more..
In a single stage unit, the absence of a stripper between treating and cracking reactorsreduces investment costs by making use of a common recycle gas system. Processobjectives determine catalyst selection for a speciﬁc unit. Product from the reactorsection is condensed, separated from hydrogen-rich gas, and fractionated into desiredproducts. Unconverted oil is recycled or used as lube, ﬂuid catalytic cracking, orethylene plant feedstock.The advanced partial conversion unicracking process read more..
mode and arranged in series. In a once-through operation, conversion rates of>95%are achieved. Substantial conversion of asphaltene constituents, desulfurization, anddenitrogenation takes place at high levels of residue conversion. Temperature iscontrolled by a recycle gas quench system.The ﬂow from the liquid phase hydrogenation reactors is routed to a hot separator,where gases and vaporized products are separated from unconverted material. Avacuum ﬂash recovers distillates in the hot read more..
It is apparent that the conversion of heavy oils and residua requires new lines ofthought to develop suitable processes (Celestinos et al., 1975). Indeed, the use ofthermal process (carbon rejection processes) and of hydrothermal processes(hydrogen addition processes), which were inherent in the reﬁneries designed toprocess lighter feedstocks, will not necessarily be useful for such feedstocks. This hasbrought about, and will continue to bring about in the reﬁnery of the future, and read more..
Slurry-phase hydrocracking of heavy oil and the latest development of dispersedcatalysts present strong indications that such technologies will play a role in futurereﬁneries. Catalysts for slurry-phase hydrocracking of heavy oil have undergone twodevelopment phases:1.Heterogeneous solid powder catalysts, which have low catalytic activity and will producea large number of solid particles in bottom oil making the catalyst difﬁcult to dispose andutilize.2.Homogeneous dispersed catalysts, which read more..
and the use of biomass as feedstock should help reﬁners meet emissions reductionrequirements for carbon dioxide.9.6Relevant PatentsUnited States Patent 7,749,373 July 6 2010. Hydrocracking Process. Hansen, J.A., Blom, N.J.,and Ward, J.W.A process for hydrocracking a hydrocarbon feedstock comprising components boiling above343C. into a middle distillate fraction in the presence of hydrogen under hydrocrackingconditions, comprising contacting the hydrocarbon feedstock in a ﬁrst hydrocracking read more..
volume of 0.5 to 1.4 cm.sup.3/g, 2–50 nanometers’ mesopore volume of not less than 60%and an average pore diameter of 3–6 nanometers, the iron being carried on the active carbonin an amount of 1 to 20 wt. % to the active carbon. The hydrocracking process using thecatalyst includes a ﬁrst step of conducting hydrocracking at a temperature within the range of360–450C. at a hydrogen partial pressure of 2–14 MPaG and a second step of conductinghydrocracking at a temperature within the read more..
9.7ReferencesAalund, L.R., 1981. Oil Gas J. 79 (13) 70 and 79 (37), 69.Bauman, R.F., Aldridge, C.L., Bearden Jr., R., Mayer, F.X., Stuntz, G.F., Dowdle, L.D., et al.,1993. Preprints. Oil Sands - Our Petroleum Future. Alberta Research Council, Edmonton,Alberta, Canada, p. 269.Bearden, R., Aldridge, C.L., 1981. Energy Progr. 1, 44.Billon, A., Morel, F., Morrison, M.E., Peries, J.P., 1994. Converting Residues with IPP’sHyvahl and Solvahl Processes. Revue Institut Franc¸ais du Pe´trole 49 (5), read more..
Kobayashi, S., Kushiyama, S., Aizawa, R., Koinuma, Y., Inoue, K., Shmizu, Y., et al., 1987.Ind. Eng. Chem. Res. 26, 2241–2245.Kressmann, S., Morel, F., Harle´, V., Kasztelan, S., 1998. Catalysis Today 43, 203–215.Kressmann, S., Harle´, V., Kasztelan, S., Guibard, I., Tromeur, P., Morel, F., 1999. Abstracts.National Meeting, American Chemical Society, New Orleans. 22–26 August.Kressmann, S., Boyer, C., Colyar, J.J., Schweitzer, J.M., Viguie´, J.C., 2000. Revue InstitutFranc¸ais du read more..
Suchanek, A.J., Moore, A.S., 1986. Oil Gas J. 84 (31), 36.Sue, H. 1989. Proceedings. 4th UNITAR/UNDP Conference on Heavy Oil and Tar Sands.5: 117.Swaddle, T.W., 1997. Inorganic Chemistry. Academic Press Inc., New York.Thompson, G.J., 1997. In: Meyers, R.A. (Ed.), Handbook of Petroleum Reﬁning Processes.McGraw-Hill, New York. (Chapter 8.4).Toulhoat, H., Szymanski, R., Plumail, J.C., 1990. Catalysis Today 7, 531.Towler, G.P., Mann, R., Serriere, A.J.L., Gabaude, C.M.D., 1996. Ind. Eng. Chem. read more..
10 Reﬁnery of the Future10.1IntroductionReﬁning technology has evolved considerably over the last century in response tostimuli such as, (1) increasing demand for gasoline and diesel fuel as well as fuel oil,(2) higher demand for petrochemicals as building blocks for clothing and consumergoods, and (3) the need to for more environmentally friendly processes and products.The reﬁning industry has been subject to four major forces, which have hastenedthe development of new processes, read more..
heavy feedstocks, have higher hydrocracking and hydrotreating capacity, and alsowill use more efﬁcient processes.High conversion reﬁneries will move to gasiﬁcation of feedstocks, for the devel-opment of alternative fuels and to enhance equipment usage. It is likely thatsynthesizing fuels from simple basic reactants (e.g. synthesis gas) will increase, whenit becomes uneconomical to produce super clean transportation fuels throughconventional reﬁning processes. Fischer-Tropsch plants read more..
until approximately half the original supply has been exhausted. At that point, a peakin sustainable output is attained, after which production begins an irreversible decline;until the point where it becomes too expensive to recover the remaining in-groundmaterial.In accordance with Hubbert’s postulate, many scientists and engineers believe thatthe midway point (the peak of the bell curve) in the depletion of the original worldpetroleum inheritance has been reached and severe depletion of the read more..
in the production of all goods and services. Any decrease in the availability of energywill therefore have exceptionally serious economic impacts (Speight and Ozum,2002; Hsu and Robinson, 2006; Gary at al, 2007; Speight, 2007).Over the longer term, primary global energy demand is expected to increase by50–60% by the year 2030, driven primarily by population growth and the desire forbetter living standards. Conventional oil and gas alone are unlikely to satisfy thedemand growth in its seminal read more..
Reﬁneries therefore need to be constantly adapted and upgraded to remain viableand responsive to ever changing patterns of crude supply and product marketdemands. As a result, increasingly complex and expensive processes have beenintroduced to gain higher yields of lower boiling products from the higher boilingfractions and residua.Finally, the yields and quality of reﬁned petroleum products produced by any givenoil reﬁnery depends on the mixture of crude oil used as feedstock and the read more..
of the residue behind as coke; and then pipeline the upgraded material out as syntheticcrude. In this method, the crude is fractionated and the residue is coked. The products ofthe coking operation, and in some cases some of the residue, are hydrotreated. Thehydrotreated materials are recombined with the fractionated light materials to formsynthetic crude that is then transported to market in a pipeline. A portion of the crudemay or may not be bypassed around the processing units. There are read more..
high-nitrogen, and high-aromatics (such as polynuclear aromatic) components. Acontrolled visbreaking treatment would clean up such crude oils by removing theseundesirable constituents, which, if not removed, would cause problems further downthe reﬁnery sequence, as coke or sediment.High acid crude oils cause corrosion in the atmospheric and vacuum distillationunits. In addition, overhead corrosion is caused by the mineral salts; magnesium;calcium; and sodium chloride, which are hydrolyzed to read more..
competitive advantage, and contribute to the attainment of national environmentaltargets. Bioprocessing routes have a number of compelling advantages overconventional petrochemicals production. However, it is only in the last decade thatsufﬁcient progress has been made in biotechnology has facilitated the commerciali-zation of a number of plant-based chemical processes.Plants offer a unique and diverse feedstock for chemicals manufacture. Plantbiomass can be gasiﬁed to produce synthesis gas; read more..
well the inorganic catalysts used in traditional chemical processes, could possibly beused to process these materials.The source biomass could be supplied by anything from corn, sugar cane, grasses,wood, and soybeans to algae. The relatively modest amounts of biomass that arerequired to meet this demand means that corn or other food crops could be usedwithout creating the competition for food that has arisen over corn-based ethanol fuelin the US. In fact Shanks says:“In fact, it is believed read more..
replace equivalent or identical products that are currently obtained from crude oil,coal or gas.By producing multiple products, a bioreﬁnery can take advantage of the differ-ences between biomass components and intermediates, and maximize the valuederived from each feedstock. It may, for example, produce one or several low-volume,but high-value, chemical products and a low-value, but high-volume liquid trans-portation fuel, while at the same time generating electricity and process heat for read more..
10.4Coal Liquids ReﬁneryReﬁnery feedstocks from coal (coal liquids) have not been dealt with elsewhere in thistext but descriptions are available from other sources (Speight, 1994, 1998).The Bergius process was one of the early processes for the production of liquidfuels from coal. In the process, lignite or sub-bituminous coal was ﬁnely ground andmixed with heavy oil recycled from the process. Catalyst was typically added to themixture and the mixture was pumped into a reactor. The read more..
The gasiﬁcation may be attained by means of any one of several processes or even bygasiﬁcation of coal in place (underground, or in situ, gasiﬁcation of coal, Section 5.5).In terms of liquids from coal that can be integrated into a reﬁnery, this representsthe most attractive option and does not threaten to bring on incompatibility problemsas can occur when phenols are present in the coal liquids.The Fisher-Tropsch process is discussed in further detail in section 10.6.2.Air pollution read more..
from the gasoline product by appropriate treatment processes. The same will apply tothe nitrogen and sulfur-containing constituents.Catalytic hydrodesulfurization processes are not a good solution for the removal ofsulfur constituents from gasoline when high proportions of unsaturated constituentsare present, since a signiﬁcant amount of the hydrogen would be taken up by theirhydrogenation. If this is desirable, however, then catalytic hydrogenation processeswould be effective.Thus, shale oil read more..
A preferred way of treating the shale oil involves using a moving bed reactorfollowed by a fractionation step to divide the wide-boiling-range crude oil producedinto two separate fractions. The lighter fraction is hydrotreated for the removal ofresidual metals, sulfur, and nitrogen; whereas the heavier fraction is cracked ina second ﬁxed bed reactor normally operated under high-severity conditions.Arsenic removed from the oil by hydrotreating remains on the catalyst, generatinga material that read more..
As petroleum supplies decrease, the desirability of producing gas from othercarbonaceous feedstocks will increase, especially in those areas where natural gas isin short supply. It is also anticipated that costs of natural gas will increase, allowingcoal gasiﬁcation to compete as an economically viable process. Research in progresson a laboratory and pilot-plant scale should lead to the development of new processtechnology by the end of the century, thus accelerating the industrial use of read more..
have slightly higher temperatures, and are suitable for higher rank coals. Fuelthroughput is higher than for the ﬁxed bed, but not as high as for the entrained ﬂowgasiﬁer. The conversion efﬁciency is typically low, so recycle or subsequentcombustion of solids is necessary to increase conversion. Fluidized bed gasiﬁersare most useful for fuels that form highly corrosive ash that would damage thewalls of slagging gasiﬁers. The ash is removed dry or as heavy agglomerates –a read more..
10.6.2 Fischer-Tropsch SynthesisIn practice, the Fischer-Tropsch reaction is carried out at temperatures of 200 to350oC (390 to 660oF) and at pressures of 75 to 4000 psi (0.5 to 4.1 MPa). Thehydrogen/carbon monoxide ratio is usually 2.2:1 or 2.5:1. Since up to three volumesof hydrogen may be required to achieve the next stage of the liquids production, thesynthesis gas must then be converted by means of the water-gas shift reaction to thedesired level of hydrogen:COþ H2O/CO2 þ H2After this, read more..
to be considered. In fact, any technological advance in this ﬁeld, such as better energyintegration or the oxygen transfer ceramic membrane reformer concept, will speed upthe rate at which the synfuels technology will become common practice.There are large coal reserves across the world, which may be used increasingly asa fuel source during oil depletion. The technology described here could be used toprovide interim transportation fuel if conventional oil were to become prohibitivelyexpensive. read more..
Visbreaking, or even hydrovisbreaking – i.e., visbreaking in an atmosphere ofhydrogen or in the presence of a hydrogen donor material (Chapter 5), the longignored step-child of the reﬁning industry, may see a surge in use as a pretreatmentprocess. Management of the process to produce a liquid product that has been freed ofthe high potential for coke deposition, by taking the process parameters into theregion where sediment forms either in the absence or presence of (for example)a metal oxide read more..
Other areas of future process modiﬁcation will be in the extractor tower internals,studies with higher molecular weight solvent, accurate estimation of physical prop-erties of mix stream, studies in combination with other processes and ﬁrming updesign tools for supercritical solvent recovery conﬁguration.In the long-term, new desulfurization technologies or evolution of the oldertechnologies (Chapter 8) will reduce the need for hydrogen. At the same time,reﬁneries are constantly faced read more..
naphtha, jet fuel, diesel, and lube base oil can be produced through this technology.The hydrocracker provides a better balance of gasoline and distillates, improvesgasoline yield, octane quality, and can supplement the ﬂuid catalytic cracker in theupgrading of heavy feedstocks. In the hydrocracker, light fuel oil is converted intolighter products under a high hydrogen pressure and over a hot catalyst bed – the mainproducts are naphtha, jet fuel, and diesel oil.For heavy and even read more..
well be the gasiﬁcation reﬁnery (Figure 10.5). This type of reﬁnery approaches that ofa petrochemical complex, and is capable of supplying the traditional reﬁned products,but can also meet much more severe speciﬁcations. It can also produce petrochemicalintermediates such as oleﬁns, aromatics, hydrogen, and methanol.As already noted above, an integrated gasiﬁcation combined cycle (IGCC) can beused to raise power from feedstocks such as vacuum and cracked residua, in addition tothe read more..
The production of high-quality fuels will result in a higher demand for relatedhydrogen and conversion technologies. For example, the current desulfurization andconversion technologies use relatively large amounts of hydrogen, which is an energyintensive product, and increased hydrogen consumption will lead to increased energyuse and operation expenses, unless more efﬁcient technologies for hydrogenproduction are developed.The demand for high value petroleum products will maximize the read more..
70 atmospheres and a non-thermal plasma discharge is generated within the non-thermalplasma reactor. The carbonaceous material and the oxygen carrier are exposed to the non-thermal plasma discharge, resulting in the formation of a product gas in the non-thermal plasmareactor, which product gas comprises substantial amounts of hydrocarbons, such as methane,hydrogen and/or carbon monoxide.United States Patent 7,735,935 June 15, 2010. In situ thermal processing of an oil shaleformation containing read more..
In some embodiments, heat from the one or more heat sources may pyrolyze at least somehydrocarbons in a part of a subsurface formation. Hydrocarbons and/or other products may beproduced from a subsurface formation. Certain embodiments describe apparatus, methods, and/or processes used in treating a subsurface or hydrocarbon containing formation.United States Patent 7,7635,024 December 22 2009. Heating tar sands formations to visbreak-ing temperatures. Karanikas, J.M., Colmenares, T.R., Zhang, read more..
Marcilly, C., 2003. Present status and future trends in catalysis for reﬁning and petrochemi-cals. Journal of Catalysis 216 (1–2), 47–62.Mut, S., 2005. Shell Unconventional Resources Energy. National Academies Trends in OilSupply/Demand and the Potential for Peaking of Conventional Oil Production. Wash-ington, DC. October 20–21.Penning, R.T., 2001. Petroleum Reﬁning: A Look at The Future. Hydrocarbon Processing 80(2), 45–46.Rostrup-Nielsen, J.R., 2004. Fuels and Energy for the read more..
GlossaryThe following list represents a selection of deﬁnitions that are commonly used inreference to petroleum and biomass and will hopefully be of use to the reader.ABN separation:A method of fractionation by which petroleum is separated into acidic,basic, and neutral constituents.Absorber:See Absorption tower.Absorption gasoline:Gasoline extracted from natural gas or reﬁnery gas by contacting theabsorbed gas with an oil and subsequently distilling the gasoline from the read more..
Adsorption gasoline:Natural gasoline (q.v.) obtained an the adsorption process from wet gas.Afterburn:The combustion of carbon monoxide (CO) to carbon dioxide (CO2); usually inthe cyclones of a catalyst regenerator.After ﬂow:Flow from the reservoir into the wellbore that continues for a period after the wellhas been shut in; after-ﬂow can complicate the analysis of a pressure transient test.Air-blown asphalt:Asphalt produced by blowing air through residua at elevated temperatures.Air read more..
Alumina (Al2O3):Used in separation methods as an adsorbent and in reﬁning as acatalyst.American Society for Testing and Materials (ASTM):The ofﬁcial organization in theUnited States for designing standard tests for petroleum and other industrial products.Amine washing:A method of gas cleaning whereby acidic impurities such as hydrogensulﬁde and carbon dioxide are removed from the gas stream by washing with an amine(usually an alkanolamine).Anaerobic digestion:Decomposition of biological read more..
Arosorb process:A process for the separation of aromatics from nonaromatics by adsorptionon a gel from which they are recovered by desorption.Asphalt:The nonvolatile product obtained by distillation and treatment of an asphaltic crudeoil; a manufactured product.Asphalt cement:Asphalt especially prepared as to quality and consistency for direct use inthe manufacture of bituminous pavements.Asphalt emulsion:An emulsion of asphalt cement in water containing a small amount ofemulsifying read more..
Bari-Sol process:A dewaxing process which employs a mixture of ethylene dichloride andbenzol as the solvent.Barrel (bbl):The unit of measure used by the petroleum industry; equivalent to approxi-mately forty-two US gallons or approximately thirty four (33.6) Imperial gallons or 159liters; 7.2 barrels are equivalent to one tonne of oil (metric).Barrel of oil equivalent (boe):The amount of energy contained in a barrel of crude oil, i.e.approximately 6.1 GJ (5.8 million Btu), equivalent to 1,700 read more..
Bioethanol:Ethanol produced from biomass feedstocks; includes ethanol produced from thefermentation of crops, such as corn, as well as cellulosic ethanol produced from woodyplants or grasses.Biofuels:A generic name for liquid or gaseous fuels that are not derived from petroleumbased fossils fuels or contain a proportion of non fossil fuel; fuels produced from plants,crops such as sugar beet, rape seed oil or re-processed vegetable oils or fuels made fromgasiﬁed biomass; fuels made from read more..
Black strap:The black material (mainly lead sulﬁde) formed in the treatment of sour lightoils with doctor solution (q.v.) and found at the interface between the oil and the solution.Blown asphalt:The asphalt prepared by air blowing a residuum (q.v.) or an asphalt (q.v.).Bogging:A condition that occurs in a coking reactor when the conversion to coke and lightends is too slow causing the coke particles to agglomerate.Boiling point:A characteristic physical property of a liquid at which the vapor read more..
Bubble tray:A circular, perforated plates having the internal diameter of a bubble tower(q.v.), set at speciﬁed distances in a tower to collect the various fractions produced duringdistillation.Buckley-Leverett method:Theoretical method of determining frontal advance rates andsaturations from a fractional ﬂow curve.Bumping:The knocking against the walls of a still occurring during distillation of petroleumor a petroleum product which usually contains water.Bunker:A storage tank.Bunker C read more..
Carbon monoxide (CO):A lethal gas produced by incomplete combustion of carbon-containing fuels in internal combustion engines. It is colorless, odorless, and tasteless.Carbon-oxygen log:Information about the relative abundance of elements such as carbon,oxygen, silicon, and calcium in a formation; usually derived from pulsed neutronequipment.Carbon rejection:Upgrading processes in which coke is produced, e.g. coking.Carbon residue:The amount of carbonaceous residue remaining after thermal read more..
Caustic wash:The process of treating a product with a solution of caustic soda to removeminor impurities; often used in reference to the solution itself.Ceresin:A hard, brittle wax obtained by purifying ozokerite; see Microcrystralline wax andOzokerite).Cetane index:An approximation of the cetane number (q.v.) calculated from the density(q.v.) and mid-boiling point temperature (q.v.); see also Diesel index.Cetane number:A number indicating the ignition quality of diesel fuel; a high cetanenumber read more..
Clay regeneration:A process in which spent coarse-grained adsorbent clays from perco-lation processes are cleaned for reuse by deoiling them with naphtha, steaming out theexcess naphtha, and then roasting in a stream of air to remove carbonaceous matter.Clay treating:See Gray clay treating.Clay wash:Light oil, such as kerosene (kerosine) or naphtha, used to clean fuller’s earth afterit has been used in a ﬁlter.Clastic:Composed of pieces of pre-existing rock.Cleanup:A preparatory step read more..
Con Carbon:See Carbon residue.Condensate:A mixture of light hydrocarbon liquids obtained by condensation of hydro-carbon vapors predominately butane, propane, and pentane with some heavier hydrocarbonsand relatively little methane or ethane; see also Natural gas liquids.Conductivity:A measure of the ease of ﬂow through a fracture, perforation, or pipe.Conformance:The uniformity with which a volume of the reservoir is swept by injectionﬂuids in area and vertical directions.Conradson carbon read more..
Criteria air pollutants:Air pollutants or classes of pollutants regulated by the Environ-mental Protection Agency; the air pollutants are (including VOCs) ozone, carbon monoxide,particulate matter, nitrogen oxides, sulfur dioxide, and lead.Cracking:A secondary reﬁning process that uses heat and/or a catalyst to break down highmolecular weight chemical components into lower molecular weight products which can beused as blending components for fuels.Cropland:Total cropland includes ﬁve read more..
Deasphaltening:Removal of a solid powdery asphaltene fraction from petroleum by theaddition of the low-boiling liquid hydrocarbons such as n-pentane or n-heptane underambient conditions.Deasphalting:The removal of the asphaltene fraction from petroleum by the addition ofa low-boiling hydrocarbon liquid such as n-pentane or n-heptane; more correctly theremoval asphalt (tacky, semi-solid) from petroleum (as occurs in a reﬁnery asphalt plant) bythe addition of liquid propane or liquid butane read more..
Diagenesis:The concurrent and consecutive chemical reactions which commence thealteration of organic matter (at temperatures up to 50C (120F) and ultimately result in theformation of petroleum from the marine sediment; see also Catagenesis and Metagenesis.Diagenetic rock:Rock formed by conversion through pressure or chemical reaction) froma rock, e.g., sandstone is a diagenetic.Diesel engine:Named for the German engineer Rudolph Diesel, this internal-combustion,compression-ignition engine works read more..
Downcomer:A means of conveying liquid from one tray to the next below in a bubble traycolumn (q.v.).Downdraft gasiﬁer:A gasiﬁer in which the product gases pass through a combustion zone atthe bottom of the gasiﬁer.Downhole steam generator:A generator installed downhole in an oil well to which oxygen-rich air, fuel, and water are supplied for the purposes of generating steam for it into thereservoir. Its major advantage over a surface steam generating facility is the losses to thewellbore read more..
Electrostatic precipitators:Devices used to trap ﬁne dust particles (usually in the size range30–60 microns) that operate on the principle of imparting an electric charge to particles inan incoming air stream and which are then collected on an oppositely charged plate acrossa high voltage ﬁeld.Eluate:The solutes, or analytes, moved through a chromatographic column (see elution).Eluent:Solvent used to elute sample.Elution:A process whereby a solute is moved through a chromatographic column read more..
Ethanol (ethyl alcohol, alcohol, or grain-spirit):A clear, colorless, ﬂammable oxygenatedhydrocarbon; used as a vehicle fuel by itself (E100 is 100% ethanol by volume), blendedwith gasoline (E85 is 85% ethanol by volume), or as a gasoline octane enhancer andoxygenate (10% by volume); formed during fermentation of sugars; used as an intoxicantand as a fuel.Evaporation:A process for concentrating nonvolatile solids in a solution by boiling off theliquid portion of the waste stream.Expanding read more..
Flammable:A substance that will burn readily.Flammable liquid:A liquid having a ﬂash point below 37.8C (100F).Flammable solid:A solid that can ignite from friction or from heat remaining from itsmanufacture, or which may cause a serious hazard if ignited.Flash point:The lowest temperature to which the product must be heated under speciﬁedconditions to give off sufﬁcient vapor to form a mixture with air that can be ignitedmomentarily by a ﬂame.Flexible-fuel vehicle (ﬂex-fuel vehicle):A read more..
Forest residues:Material not harvested or removed from logging sites in commercialhardwood and softwood stands as well as material resulting from forest managementoperations such as precommercial thinnings and removal of dead and dying trees.Forest health:A condition of ecosystem sustainability and attainment of managementobjectives for a given forest area; usually considered to include green trees, snags, resilientstands growing at a moderate rate, and endemic levels of insects and read more..
Furnace oil:A distillate fuel primarily intended for use in domestic heating equipment.Gas cap:A part of a hydrocarbon reservoir at the top that will produce only gas.Gasiﬁcation:A chemical or heat process used to convert carbonaceous material (such ascoal, petroleum, and biomass) into gaseous components such as carbon monoxide andhydrogen.Gasiﬁer:A device for converting solid fuel into gaseous fuel; in biomass systems, the processis referred to as pyrolitic distillation.Gasohol:A mixture of read more..
Gravity-stable displacement:The displacement of oil from a reservoir by a ﬂuid ofa different density, where the density difference is utilized to prevent gravity segregation ofthe injected ﬂuid.Gray clay treating:A ﬁxed-bed (q.v.), usually fuller’s earth (q.v.), vapor-phase treatingprocess to selectively polymerize unsaturated gum-forming constituents (dioleﬁns) inthermally cracked gasoline.Grain alcohol:See Ethyl alcohol.Gravimetric:Gravimetric method to weigh a residue.Gravity read more..
Heavy petroleum:See Heavy oil.Hectare:Common metric unit of area, equal to 2.47 acres. 100 hectares¼ 1 squarekilometer.Herbaceous:Non-woody type of vegetation, usually lacking permanent strong stems, suchas grasses, cereals and canola (rape).Heteroatom compounds:Chemical compounds which contain nitrogen and/or oxygen and/or sulfur and/or metals bound within their molecular structure(s).Heterogeneity:Lack of uniformity in reservoir properties such as permeability.HF alkylation:An alkylation read more..
Hydrocracking:A catalytic, high-pressure, high-temperature process for the conversion ofpetroleum feedstocks in the presence of fresh and recycled hydrogen; carbon-carbon bondsare cleaved in addition to the removal of heteroatomic species.Hydrocracking catalyst:A catalyst used for hydrocracking which typically contains sepa-rate hydrogenation and cracking functions.Hydrodenitrogenation:The removal of nitrogen by hydrotreating (q.v.).Hydrodesulfurization:The removal of sulfur by hydrotreating read more..
Immiscible displacement:A displacement of oil by a ﬂuid (gas or water) that is conductedunder conditions so that interfaces exist between the driving ﬂuid and the oil.Immunoassay:Portable tests that take advantage of an interaction between an antibody anda speciﬁc analyte. Immunoassay tests are semi-quantitative and usually rely on colorchanges of varying intensities to indicate relative concentrations.Incinerator:Any device used to burn solid or liquid residues or wastes as a method read more..
Interfacial tension:The strength of the ﬁlm separating two immiscible ﬂuids, e.g., oil andwater or microemulsion and oil; measured in dynes (force) per centimeter or milli-dynes percentimeter.Interfacial viscosity:The viscosity of the interfacial ﬁlm between two immiscible liquids.Interference testing:A type of pressure transient test in which pressure is measured overtime in a closed-in well while nearby wells are produced; ﬂow and communication betweenwells can sometimes be deduced read more..
Kerogen:A complex carbonaceous (organic) material that occurs in sedimentary rock andshale; generally insoluble in common organic solvents.Kerosene (kerosine):A fraction of petroleum that was initially sought as an illuminant inlamps; a precursor to diesel fuel.K-factor:See Characterization factor.Kilowatt (kW):A measure of electrical power equal to 1,000 watts. 1 kW¼ 3412 Btu/hr¼1.341 horsepower.Kilowatt hour - (kWh):A measure of energy equivalent to the expenditure of one kilowattfor one read more..
Liquid/liquid extraction:An extraction technique in which one liquid is shaken with orcontacted by an extraction solvent to transfer molecules of interest into the solvent phase.Liquid sulfur dioxide-benzene process:A mixed-solvent process for treating lubricating-oilstocks to improve viscosity index; also used for dewaxing.Lithology:The geological characteristics of the reservoir rock.Live cull:A classiﬁcation that includes live cull trees; when associated with volume, it is thenet volume in read more..
Medicinal oil:Highly reﬁned, colorless, tasteless, and odorless petroleum oil used asa medicine in the nature of an internal lubricant; sometimes called liquid parafﬁn.Megawatt:(MW) A measure of electrical power equal to one million watts (1,000 kW).Membrane technology gas separation processes utilizing membranes that permit differentcomponents of a gas to diffuse through the membrane at signiﬁcantly different rates.MDL:See Method detection limit.MEK-(methyl ethyl ketone):A colorless read more..
Middle-phase micro emulsion:A micro emulsion phase containing a high concentration ofboth oil and water that; when viewed in a test tube, resides in the middle with the oil phaseabove it and the water phase below it.Migration (primary):The movement of hydrocarbons (oil and natural gas) from mature,organic-rich source rocks to a point where the oil and gas can collect as droplets or asa continuous phase of liquid hydrocarbon.Migration (secondary):The movement of the hydrocarbons as a single, read more..
Mobility control:Ensuring that the mobility of the displacing ﬂuid or bank is equal to or lessthan that of the displaced ﬂuid or bank.Mobility ratio:Ratio of mobility of an injection ﬂuid to mobility of ﬂuid being displaced.Modiﬁed alkaline ﬂooding:The addition of a co-surfactant and/or polymer to the alkalineﬂooding process.Modiﬁed/unmodiﬁed diesel engine:Traditional diesel engines must be modiﬁed to heat theoil before it reaches the fuel injectors in order to handle read more..
Natural gasoline:A mixture of liquid hydrocarbons extracted from natural gas (q.v.) suitablefor blending with reﬁnery gasoline.Natural gasoline plant:A plant for the extraction of ﬂuid hydrocarbon, such as gasoline andliqueﬁed petroleum gas, from natural gas.NESHAP:National Emissions Standards for Hazardous Air Pollutants; emission standardsfor speciﬁc source categories that emit or have the potential to emit one or more hazardousair pollutants; the standards are modeled on the best read more..
Octane number:A number indicating the anti-knock characteristics of gasoline.Oil bank:See Bank.Oil breakthrough (time):The time at which the oil-water bank arrives at the producing well.Oil from tar sand:Synthetic crude oil.Oil mining:Application of a mining method to the recovery of bitumen.Oil originally in place (OOIP):The quantity of petroleum existing in a reservoir before oilrecovery operations begin.Oils:That portion of the maltenes (q.v.) that is not adsorbed by a surface-active material read more..
Particle size distribution:The particle size distribution (of a catalyst sample) expressed asa percent of the whole.Partitioning:In chromatography, the physical act of a solute having different afﬁnities forthe stationary and mobile phases.Partition ratios, K:The ratio of total analytical concentration of a solute in the stationaryphase, CS, to its concentration in the mobile phase, CM.Pattern:The areal pattern of injection and producing wells selected for a secondary orenhanced recovery read more..
Phase diagram:A graph of phase behavior. In chemical ﬂooding a graph showing therelative volume of oil, brine, and sometimes one or more micro emulsion phases. In carbondioxide ﬂooding, conditions for formation of various liquid, vapor, and solid phases.Phase properties:Types of ﬂuids, compositions, densities, viscosities, and relative amountsof oil, microemulsion, or solvent, and water formed when a micellar ﬂuid (surfactant slug)or miscible solvent (e.g., CO2) is mixed with oil.Phase read more..
Polymer augmented waterﬂooding:Waterﬂooding in which organic polymers are injectedwith the water to improve areal and vertical sweep efﬁciency.Polymer gasoline:The product of polymerization of gaseous hydrocarbons to hydrocarbonsboiling in the gasoline range.Polymerization:The combination of two oleﬁn molecules to form a higher molecular weightparafﬁn.Polymer stability:The ability of a polymer to resist degradation and maintain its originalproperties.Polynuclear aromatic compound:An read more..
Primary wood-using mill:A mill that converts round wood products into other woodproducts; common examples are sawmills that convert saw logs into lumber and pulp millsthat convert pulpwood round wood into wood pulp.Primary structure:The chemical sequence of atoms in a molecule.Primary tracer:A chemical that, when injected into a test well, reacts with reservoir ﬂuidsform a detectable chemical compound.Probable reserves:Mineral reserves mineral that are nearly certain but about which a read more..
Quad:One quadrillion Btu (1015 Btu)¼ 1.055 exajoules (EJ), or approximately 172 millionbarrels of oil equivalent.Quadrillion:1Â 1015.Quench:The sudden cooling of hot material discharging from a thermal reactor.RACT:Reasonably Available Control Technology standards; implemented in areas of non-attainment to reduce emissions of volatile organic compounds and nitrogen oxides.Rafﬁnate:That portion of the oil which remains undissolved in a solvent reﬁning process.Ramsbottom carbon residue:See read more..
Reservoir simulation:Analysis and prediction of reservoir performance with a computermodel.Residual asphalt:See Straight-run asphalt.Residual fuel oil:Obtained by blending the residual product(s) from various reﬁningprocesses with suitable diluent(s) (usually middle distillates) to obtain the required fuel oilgrades.Residual oil:Petroleum remaining in situ after oil recovery; also See Residuum.Residual resistance factor:The reduction in permeability of rock to water caused by theadsorption of read more..
SARA analysis:A method of fractionation by which petroleum is separated into saturates,aromatics, resins, and asphaltene fractions.SARA separation:See SARA analysis.Saturated steam:Steam at boiling temperature for a given pressure.Saturates:Parafﬁns and cycloparafﬁns (naphthenes).Saturation:The ratio of the volume of a single ﬂuid in the pores to pore volume, expressed asa percent and applied to water, oil, or gas separately; the sum of the saturations of each ﬂuidin a pore volume is read more..
Separator-Nobel dewaxing:A solvent (tricholoethylene) dewaxing process.Separatory funnel:Glassware shaped like a funnel with a stoppered rounded top and a valveat the tapered bottom, used for liquid/liquid separations.Shear:Mechanical deformation or distortion, or partial destruction of a polymer molecule asit ﬂows at a high rate.Shear rate:A measure of the rate of deformation of a liquid under mechanical stress.Shear-thinning:The characteristic of a ﬂuid whose viscosity decreases as the read more..
Solvent dewaxing:A process for removing wax from oils by means of solvents usually bychilling a mixture of solvent and waxy oil, ﬁltration or by centrifuging the wax whichprecipitates, and solvent recovery.Solvent extraction:A process for separating liquids by mixing the stream with a solvent thatis immiscible with part of the waste but that will extract certain components of the wastestream.Solvent gas:An injected gaseous ﬂuid that becomes miscible with oil under. reservoirconditions, and read more..
Steam stimulation:Injection of steam into a well and the subsequent production of oil fromthe same well.Steam turbine:A device for converting energy of high-pressure steam (produced in a boiler)into mechanical power which can then be used to generate electricity.Stiles method:A simple approximate method for calculating oil recovery by waterﬂood thatassumes separate layers (stratiﬁed reservoirs) for the permeability distribution.Storage stability (or storage instability):The ability read more..
Sweet crude oil:Crude oil containing little sulfur; see also Sour crude oil.Sweetening:The process by which petroleum products are improved in odor and color byoxidizing or removing the sulfur-containing and unsaturated compounds.Swelling:Increase in the volume of crude oil caused by absorption of EOR ﬂuids, especiallycarbon dioxide. Also increase in volume of clays when exposed to brine.Swept zone:The volume of rock that is effectively swept by injected ﬂuids.Synthetic crude oil read more..
Thief zone:Any geologic stratum not intended to receive injected ﬂuids in which signiﬁcantamounts of injected ﬂuids are lost; ﬂuids may reach the thief zone due to an impropercompletion or a faulty cement job.Thin layer chromatography (TLC):A chromatographic technique employing a porousmedium of glass coated with a stationary phase. An extract is spotted near the bottom of themedium and placed in a chamber with solvent (mobile phase). The solvent moves up themedium and separates the read more..
Triaxial borehole seismic survey:A technique for detecting the orientation of hydraulicallyinduced fractures, wherein a tool holding three mutually seismic detectors is clamped in theborehole during fracturing; fracture orientation is deduced through analysis of the detectedmicroseismic perpendicular events that are generated by the fracturing process.Trickle hydrodesulfurization:A ﬁxed-bed process for desulfurizing middle distillates.Trillion:1Â 1012.True boiling point (True boiling read more..
Vacuum residuum:A residuum (q.v.) obtained by distillation of a crude oil under vacuum(reduced pressure); that portion of petroleum which boils above a selected temperature suchas 510C (950F) or 565C (1050F).Vapor-phase cracking:A high-temperature, low-pressure conversion process.Vapor-phase hydrodesulfurization:A ﬁxed-bed process for desulfurization and hydroge-nation of naphtha.Vertical sweep efﬁciency:The fraction of the layers or vertically distributed zones ofa reservoir that are read more..
Waterﬂood residual:The waterﬂood residual oil saturation; the saturation of oil remaining afterwaterﬂooding in those regions of the reservoir that have been thoroughly contacted by water.Watershed:The drainage basin contributing water, organic matter, dissolved nutrients, andsediments to a stream or lake.Watson characterization factor:See Characterization factor.Watt:The common base unit of power in the metric system; one watt equals one joule persecond, or the power developed in a circuit read more..
IndexABC process, 291Acidity, 111Acids, 3Adaptation to new feedstocks, 335Gasiﬁcation, 336Additives, 76, 191Adsorption fractionation, 72Advanced partial conversion Unicrackingprocess, 305Airlift Thermofor catalytic crackingprocess, 187Alkylation chemistry, 102Alkylation processes, 63Aluminosilicate catalysts, 287Amphoteric constituents, 17, 70, 89AnalysisRepeatability, 8Reproducibility, 8APCU process, 305Argillaceous sediments, 4Aromatic constituents, 17ART process, 198ASCOT process, read more..
Carboids, 86Catalytic cracking, 40, 53, 92, 181Fixed bed process, 183Fluid bed, 183Moving bed process, 183Catalytic dewaxing process, 229Centrifuge dewaxing process, 229Coke formation, 94Catalytic cracking catalysts, 194Catalytic cracking chemistry, 92Catalytic cracking reﬁnery, 45Catalytic hydrocracking, 58Catalytic polymerization, 40Catalytic reforming, 59, 61Cellulose, 30Challenging crude, see OpportunitycrudesChemistry of coke formation, 103Cherry-P process, 164Coal liquids reﬁnery, read more..
Energy resourcesDistribution, 16Entrained ﬂow gasiﬁer, 330ET-II process, 165Eureka process, 166Extractive distillation, 49, 133, 134Extra heavy oil, 4Fat oil, 132Fats and greases, 14Ferroﬁning process, 253Fischer-Tropsch synthesis, 331Fixed bed process, 54, 60, 183, 185Flasher, 123Flash point, 130Flash zone, 123Fluid beds, 54, 60, 183Fluid catalytic cracking, 183Fluidized bed gasiﬁer, 329Fluid thermal cracking process(FTC process), 167Forces for change, 41Fossil fuels, 16, 18Fouling, read more..
Hydrocracking chemistry, 88, 94, 283Asphaltene constituents, 95Hydrocracking process, 97, 244Effect of coking, 288Evaluation, 277Once-through partial conversionprocess, 281Single-stage once-through process, 281Single-stage process, 279Single-stage recycle process, 281Slurry-phase process, 308Two-stage process, 97, 278, 279Hydrodesulfurization, 56Hydrogen management, 245Process parameters, 242, 247Hydroﬁning process, 254Hydroﬁnishing, 56Hydroﬂuoric acid alkylation, 65Hydrogenation, read more..
Naphtha, 17, 25Composition, 26Naphthenic acids, 3Chemistry, 6Corrosion, 6Properties, 5Test methods, 7Native asphalt, see BitumenNatural gas, 31Neutralization number, 7New feedstocks, 335Gasiﬁcation, 336No. 1 fuel oil, 33No. 2 fuel oil, 33No. 6 fuel oil, 33Oil ﬁeld, 17Oil price, 19Oil sand, see Tar sandOnce-through partial conversionhydrocracking process, 281Opportunity crudes, 4, 9, 320Risk management, 10Organic acids, 3Origin of petroleum, 16Orthoﬂow Fluid-Bed Catalytic Cracking,187Packed read more..
ReﬁneryCatalytic cracking, 45Coking, 45Conﬁguration, 42Hydroskimming, 43, 44Topping, 43, 44, 122Reﬁnery products, 81Reﬁning, 3Changes, 318Reﬁning capacity, 19Reﬁning chemistry, 81Reforming, 18, 59Reforming catalysts, 61Reforming chemistry, 59Rerunning, 48, 130ReservesExploitation, 316Proved, 18Reservoir, 17Residﬁning process, 259Residua, 29Residue hydroconversion process, 302ResiduumCracked, 40Vacuum, 125Residuum desulfurization process (RDSprocess), 258Residual fuel oil, 32, read more..
Tertiary biomass, 4, 14Tervahl-H process, 303Tervahl-T process, 170Thermal cracking, 40, 82, 147, 182Commercial processes, 148Thermal cracking process, 150Thermal decarboxylation, 7Thermal processes, 49Thermal reforming, 40, 59Thermochemical platform, 323Topping operation, 122Topping reﬁnery, 43, 44Total acid number, 7Transportation, 18Transportation fuels, 5Tray, 122Tray columns, 127Tube and tank cracking process, 51Two-stage hydrocracking process, 97,278, 279Ultraﬁning process, read more..
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