Oil Refining 04

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Oil Refining and Products

CHAPTER DECEMBER 2004

DOI: 10.1016/B0-12-176480-X/00259-X

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Abdullah M. Aitani

King Fahd University of Petroleum and Miner

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Oil Refining and Products

ABDULLAH M. AITANIKing Fahd University of Petroleum and Minerals

Dhahran, Saudi Arabia

1. Overview of Refinery Processing

2. Crude Oil and Products

3. Light Oil Processing

4. Heavy Distillate Processing

5. Residual Oil Processing

6. Treating Processes7. Environmental and Future Issues

Glossary

alkylation A process using sulfuric acid or hydrofluoricacid as a catalyst to combine light olefins and isobutaneto produce a high-octane product known as alkylate.

1API gravity A scale of liquid specific gravity (SG) thatindicates the lightness or heaviness of hydrocarbons,defined by [(141.5/SG) 131.5].

catalytic cracking A process for the breaking-up of heavierhydrocarbons into lighter hydrocarbon fractions by theuse of heat and catalysts.

cetane number A measure of ignition quality for kerosene,diesel, and heating oil, using a single-cylinder engine.

coking A process for thermally converting and upgradingheavy residues into lighter products and by-productpetroleum coke.

crude oil A complex mixture of hydrocarbons containinglow percentages of sulfur, nitrogen, and oxygen com-pounds and trace quantities of many other elements.

deasphalting A process for removing asphaltic materialsfrom reduced crude, using liquid propane to dissolvenonasphaltic compounds.

hydrocracking A process used to convert heavier feedstockinto lower boiling point, higher value products. Theprocess employs high pressure, high temperature, acatalyst, and hydrogen.

hydrodesulfurization A catalytic process for the removal ofsulfur compounds from hydrocarbons using hydrogen.

isomerization A catalytic process for the conversion andskeletal rearrangement of straight-chain hydrocarbonsinto branched-chain molecules of higher octane number.

methyl tertiary butyl ether (MTBE) An ether added togasoline to raise octane number and enhance combustion.

octane number A measure of resistance to knocking ofgasoline under laboratory conditions that simulate citydriving conditions.

olefins Unsaturated hydrocarbons, such as ethylene andpropylene, that have a double carbon bond, with themolecular formula CnH2n.

paraffins Saturated aliphatic hydrocarbons with the mole-

cular formula CnH2n2.reforming A process for the transformation of naphthainto products with higher octane number. Reformingcomprises isomerization, cracking, polymerization, anddehydrogenation.

visbreaking A low-temperature cracking process usedto reduce the viscosity or pour point of straight-runresidues.

This article discusses the various aspects of petro-leum refining and oil products as a primary energysource and as a valuable feedstock for petrochem-icals. The main objective of refining is to convertcrude oils of various origins and different composi-tions into valuable products and fuels having thequalities and quantities demanded by the market.Various refining processes, such as separation, con-version, finishing, and environmental protection, arepresented and briefly discussed. The ever-changingdemand and quality of fuels, as well as environ-mental issues and the challenges facing the refiningindustry, are also highlighted. Environmental regula-tions have played a significant role in the progress ofthe refining industry and may even change thecompetition between petroleum and other alternativeenergy sources.

1. OVERVIEW OF REFINERYPROCESSING

1.1 Introduction

Refining is the processing of crude oil into a numberof useful hydrocarbon products. Processing utilizes

Encyclopedia of Energy, Volume 4. r 2004 Elsevier Inc. All rights reserved. 715


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chemicals, catalysts, heat, and pressure to separateand combine the basic types of hydrocarbon mole-cules naturally found in crude oil into groups ofsimilar molecules. The refining process also rear-ranges their structures and bonding patterns intodifferent hydrocarbon molecules and compounds.

Therefore, it is the type of hydrocarbon (paraffinic,naphthenic, or aromatic) and its demand thatconfigure the refining industry. Petroleum refininghas evolved continuously in response to changingdemands for better and different products. The trendin demand has also been accompanied by continuousimprovement in product quality, such as octanenumber for gasoline and cetane number for diesel.

The original requirement was to produce kerosenefor household use, followed by the development ofthe internal combustion engine and the production oftransportation fuels (gasoline, diesel, and fuels).Refineries produce a variety of products including

many required as feedstocks for the petrochemicalindustry. Early refining was the simple distillation(fractionation) of crude oil followed by the develop-ment in the 1920s of the thermal cracking processes,such as visbreaking and coking. The processes crackheavy fuels into more useful and desirable productsby applying pressure and heat.

In the early 1940s, the catalytic processes weredeveloped to meet the increasing demand of gasolineand higher octane numbers. Processes such ascatalytic cracking, alkylation, isomerization, hydro-cracking, and reforming were developed throughout

the 1960s to increase gasoline yields and improveantiknock characteristics. Some of these processesalso produced valuable feedstocks for the modernpetrochemical industry. In the 21st century, therefinery uses an array of various catalytic andnoncatalytic processes to meet new product specifica-tions and to convert less desirable fractions into morevaluable liquid fuels, petrochemical feedstocks, andelectricity. The refinery has shifted from only physicalseparations to something close to a chemical plant.

1.2 Refinery Operations

Modern refineries incorporate fractionation, conver-sion, treatment, and blending operations and mayalso include petrochemical processing. Most lightdistillates are further converted into more usableproducts by changing the size and structure of thehydrocarbon molecules through cracking, reforming,and other conversion processes, as discussed furtherin this article. Figure 1 presents a typical scheme of ahigh-conversion refinery.

Various streams are subjected to various separa-tion processes, such as extraction, hydrotreating, andsweetening, to remove undesirable constituents andimprove product quality. In general, petroleumrefining operations can be grouped as follows:

Fractionation (distillation) is the separation ofcrude oil in atmospheric and vacuum distillationtowers into groups of hydrocarbon compounds ofdiffering boiling-point ranges called fractions orcuts. Light oil processing prepares light distillates

through rearrangement of molecules using isomer-ization and catalytic reforming or combinationprocesses such as alkylation and polymerization. Heavy oil processing changes the size and/or

structure of hydrocarbon molecules through thermalor catalytic cracking processes. Treatment and environmental protection pro-

cesses involve chemical or physical separation, suchas dissolving, absorption, or precipitation, using avariety and combination of processes includingdrying, solvent refining, and sweetening.

1.3 World Refining

World refining capacity reached 81.9 million barrels/day in 2002 and is expected to increase by 4.3% peryear to 115 million barrels/day by 2020. Table Ipresents a regional distribution capacity of majorrefining processes. There are 722 refineries in 116

countries, with more than 200 refineries in Asia-Pacific regions alone. The United States has main-tained its leading position as the largest and mostsophisticated oil-refining region. Approximately25% of worldwide refining capacity is located inNorth America and another 25% is located in Asiafollowed by 17% in Western Europe. Remainingregions process approximately 33% of the worldscrude oil in medium-type conversion refiningschemes. World capacities of various refining pro-cesses are presented in Table II. Hydrotreating alonerepresents approximately 50% of total crude capa-city, whereas all catalytic processes represent ap-

proximately 82% of crude capacity.In general, the refining industry has always beencharacterized as a high-volume, low-profit-marginindustry. World refining continues to be challengedby uncertainty of supply, difficult market conditions,government regulation, availability of capital, andslow growth. Although shipping of refined productshas been increasing over the years, a close connectionremains between domestic markets and domestic

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production. This explains the large differences in

refinery schemes from one country to another andfrom one region to another.

2. CRUDE OIL AND PRODUCTS

2.1 Type and Composition of Crude Oils

Crude oil is a mixture of hydrocarbon compoundssuch as paraffins, naphthenes, and aromatics plus

small amounts of organic compounds of sulfur,

oxygen, and nitrogen, in addition to small amountsof metallic compounds of vanadium, nickel, andsodium. Although the concentration of nonhydrocar-bon compounds is very small, their influence oncatalytic petroleum processing is large. There are alarge number of individual components in a specificcrude oil, reaching approximately 350 hydrocarbonsand approximately 200 sulfur compounds. A specificcrude oil can comprise a very large number of

C4

TreaterLt Naph

H2

Gas plantLPG

Polymerization

Olefins

Alkylation

Gas

Gas from other units

Hv Naph

Kerosene

ATM Gas oil

VacGas oil

Hydrotreater

Hydrotreater

Hydrotreater

Hydrotreater

Cat cracker

Lube

AsphaltVacuum

crudedistillation

Coker

Coke

To asphalt blowing

To lube plant

Fuel oils

Kerosene

Aromatics

Gasoline

Reformer Aromaticextraction

Atmospheric

crude

distillation

Crude oil

Crude

desalter

FIGURE 1 Schematic diagram of a high-conversion refinery. Cat cracker, catalytic cracker; Hv Naph, heavy naphtha; LtNaph, light naphtha; LPG, liquefied petroleum gas; Vac gas oil, vacuum gas oil; ATM gas oil, atmospheric gas oil.

Oil Refining and Products 717


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compounds that are not easily identifiable or quanti-fiable. Most of these compounds have a carbonnumber less than 16 and these form a relatively highproportion of crude oil.

The elemental composition of crude oils dependson the type and origin of the crude; however, theseelements vary within narrow limits. The proportions

of these elements in a typical crude are 84.5%carbon, 13% hydrogen, 13% sulfur, and less than1% each of nitrogen, oxygen, metals, and salts. Thephysical properties of crude oils vary within a widerange. Crude oils are defined in terms of API(American Petroleum Institute) gravity: the higherthe API gravity, the lighter the crude. Crude oils withlow carbon, high hydrogen, and high API gravity areusually rich in paraffins and tend to yield greater

proportions of gasoline and light petroleum pro-ducts; those with high carbon, low hydrogen, andlow API gravities are usually rich in aromatics.

Crude oils can be classified in many differentways, generally based on their density (API), sulfurcontent, and hydrocarbon composition. Condensate

ranks highest, with densities reaching more than 501API, whereas densities of heavy crudes may reach aslow as 101API. In general, refinery crude base stocksconsist of mixtures of two or more different crudeoils. There are more than 600 different commercialcrude oils traded worldwide. In 2002, world oilproduction reached 66 million barrels/day, 40% ofwhich is produced by members of the Organizationof Petroleum Exporting Countries. Despite all energyalternatives, crude oil will remain the worldsprimary energy source, constituting approximately40% of world energy up to the year 2020.

2.2 Crude Oil Processing

As a first step in the refining process, water, inorganicsalts, suspended solids, and water-soluble trace metalcontaminants are removed by desalting using chemi-cal or electrostatic separation. This process is usuallyconsidered a part of the crude distillation unit. Thedesalted crude is continuously drawn from the top ofthe settling tanks and sent to the crude fractionationunit. Distillation of crude oil into straight-run cutsoccurs in atmospheric and vacuum towers. The mainfractions obtained have specific boiling-point ranges

and can be classified in order of decreasing volatilityinto gases, light distillates, middle distillates, gas oils,and residue. The composition of the products isdirectly related to the characteristics of the crudeprocessed. Desalted crude is processed in a verticaldistillation column at pressures slightly above atmo-spheric and at temperatures ranging from 345 to3701C (heating above these temperatures may causeundesirable thermal cracking). In order to furtherdistill the residue from atmospheric distillation athigher temperatures, reduced pressure is required toprevent thermal cracking. Vacuum distillation re-sembles atmospheric distillation except that larger

diameter columns are used to maintain comparablevapor velocities at the reduced pressures.

2.3 Transportation Fuels

Major oil products are mainly transportation fuelsthat represent approximately 52% of total world-wide oil consumption. Gasoline and diesel are themain concern, along with a large number of special

TABLE II

World Refining Processes and Their Share of Crude Oil Capacity

Process

Capacity (million

barrels/day)

% of crude

capacity

Vacuum distillation 26.7 32.6

Coking 4.2 5.1

Visbreaking 3.7 4.5

Catalytic cracking 14.2 17.3

Naphtha reforming 11.2 13.7

Hydrocracking 4.4 5.4

Hydrotreating 38.4 46.9

Alkylation 1.9 2.3

Polymerization 0.2 0.2

Aromatics production 1.2 1.5Isomerization 1.5 1.8

Oxygenates 0.3 0.4

TABLE I

Regional Distribution of Refining Operations Worldwide

Regional capacity

Region No. of refineries million barrels/day %

North America 160 20.3 24.8

South America 69 6.7 8.2

Western Europe 105 14.6 17.8

Eastern Europe 95 10.6 12.9

Asia 202 20.2 24.7

Middle East 46 6.3 7.7

Africa 45 3.2 3.9

Total 722 81.9 100



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petroleum-based products. Crude oil type and refin-ing configuration determine the quantity and qualityof oil products. Tables III and IV present sometypical data on the volume of atmospheric distillatecuts and refined products derived from the processingof Arabian light crude oil. For example, approxi-

mately 8085 vol% of the refined products producedin a medium-type conversion refinery have a boilingtemperature lower than 3451C compared to anamount of 55 vol% found in Arabian crude oil (seeTables III and IV). Almost half of the products aregasoline and lighter distillates. The demand fortransportation fuels and petrochemical feedstockshas been increasing steadily compared to thedecreasing demand for heating fuels and residualfuel oil, which are being replaced by natural gas.

2.3.1 GasolineMotor gasoline is the highest volume refinery

product, having a mixture of hydrocarbons withboiling points ranging from ambient temperature toapproximately 2051C. It flows easily, spreads quickly,and may evaporate completely in a few hours undertemperate conditions. It is highly volatile andflammable. Gasoline is made up of different refinerystreams, mainly straight-run naphtha, isomerizedC5/C6 paraffins, reformate, hydrocracking, fluidcatalytic cracking (FCC) gasoline, oligomerate, alky-late, and ethers. The most environmentally friendlygasoline comes from branched paraffins. The im-

portant qualities for gasoline are octane number(antiknock), volatility (starting and vapor lock),vapor pressure, and sulfur content (environmentalcontrol). Additives are often used to enhance gasolineperformance and to provide protection againstoxidation and rust formation. Table V presents some

typical data for current and future specifications forgasoline in Europe.

2.3.2 Diesel FuelDiesel fuel is usually second in volume next togasoline. Diesel blend consists of cuts from atmo-spheric distillation, hydrocracking, FCC light cycle oil,and some products obtained from visbreaking andcoking. The main property of diesel fuel for auto-motive engine combustion is cetane number, which is ameasure of engine start-up and combustion. Diesel fueland domestic heating oils have boiling point ranges ofapproximately 2003701C. The desired properties ofthese distillate fuels include controlled flash and pourpoints, clean burning, and no deposit formation instorage tanks. Sulfur reduction and cetane improve-ment have been extensively investigated to produceultralow-sulfur diesel (ULSD). Meeting future specifi-cations for ULSD of 1015ppm sulfur will requiresignificant hydrotreating investment. Table VI presentssome typical data for current and future specificationsfor diesel fuel in Europe.

2.3.3 Jet Fuel (Kerosene)Jet fuel is the third most important transportation fuel.

It is a middle-distillate product that is used for jets(commercial and military) and is used around theworld in cooking and heating (kerosene). When usedas a jet fuel, some of the critical qualities are freeze

TABLE V

Current and Future Specifications for Gasoline

Year

Specificationa 2000 2005

Sulfur (ppm) 150 3050

Benzene content (vol%, maximum) 1 1

Aromatics (vol%, maximum) 42 35

Olefins (vol%, maximum) 18 15

Oxygen (wt%, maximum) 2.7 2.3

RVP (kPa) 60 50

RON/MON (minimum) 95/85 95/85

aRVP, Reid vapor pressure; RON, research octane number;MON, motor octane number.

TABLE III

Atmospheric Distillates Derived from Arabian Light Crude Oil

Product name Boiling point (1C) Volume (%)

Light naphtha 1090 8

Heavy naphtha 90200 21

Kerosene 200260 11

Gas oil 260345 15

Residue 345 45

TABLE IV

Typical Refined Products Derived from Arabian Light Crude Oil

(Medium-Conversion Refinery)

Product name Carbon no. Boiling point (1C) Volume (%)

Gases 14 4040 5

Gasoline 510 40200 45

Kerosene/jet 1016 150260 5

Fuel oil 2070 200345 25

Residue 470 4345 20



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point, flash point, and smoke point. Commercial jetfuel has a boiling point range of approximately 1902751C and that of military jet fuel is 552851C.Kerosene, with less critical specifications, is used for

lighting, heating, solvents, and blending into dieselfuel.n-Paraffins in the range C12C14may be extractedfrom kerosene for use in the production of detergents.

2.4 Other Oil Products

2.4.1 Refinery GasesRefinery gases are the lightest hydrocarbons contain-ing a mixture of gases from methane to liquefiedpetroleum gas (LPG) and some pentanes. The gasesare processed to separate LPG, which consistsprincipally of propane and butane. Other refinery

gases include lighter paraffins, unsaturates, andhydrogen sulfide. LPG is used as fuel and as anintermediate in the manufacture of olefins and selectedpetrochemical feedstocks. Butanes are also used in themanufacture of ethers and to adjust the vapor pressureof gasoline. LPG is also used in transportation and indomestic and household applications.

2.4.2 Petrochemical FeedstocksLight olefins from FCC and benzene, toluene, xylenes(BTX) aromatics from naphtha reforming are themain petrochemical feedstocks derived from refi-

neries. These products are the basis for integratingrefining and petrochemical operations. Olefins in-clude propylene and butanes, whereas benzene andxylenes are precursors for many valuable chemicalsand intermediates, such as styrene and polyesters.

2.4.3 Residual Fuel OilResidual fuel oil is the least valuable of the refinersproducts, selling at a price below that of crude oil.

Residual fuels are difficult to pump and may beheavier than water; they are also difficult to disperseand are likely to form tar balls, lumps, andemulsions. Many marine vessels, power plants,commercial buildings, and industrial facilities useresidual fuels or combinations of residual and

distillate fuels for heating and processing. The twomost critical properties of residual fuels are viscosityand low sulfur content for environmental control.

2.4.4 Coke and AsphaltPetroleum coke is produced in coking units and isalmost pure carbon with a variety of uses fromelectrodes to charcoal briquets. Asphalt is a semisolidmaterial produced from vacuum distillation and isclassified into various commercial grades. It is usedmainly for paving roads and roofing materials.

2.4.5 Lubricants

Vacuum distillation and special refining processesproduce lube-oil base stocks. Additives such asantioxidants and viscosity enhancers are blendedinto the base stocks to provide the characteristicsrequired for motor oils, industrial greases, lubricants,and cutting oils. The most critical quality is a highviscosity index, which provides for greater consis-tency under varying temperatures.

3. LIGHT OIL PROCESSING

3.1 Catalytic Naphtha Reforming

Catalytic naphtha reforming combines a catalyst,hardware, and processing to produce high-octanereformate for gasoline blending or BTX aromaticsfor petrochemical feedstocks. Reformers are also thesource of much needed hydrogen for hydroproces-sing operations. Reforming reactions comprise crack-ing, polymerization, dehydrogenation, andisomerization, which take place simultaneously.Universal Oil Products (UOP) and Axens-InstitutFrancais du Petrole (IFP) are the two major licensorsand catalyst suppliers for catalytic naphtha reform-ing. Reforming processes differ in the mode of

operation [semiregenerative or continuous catalystregenerative (CCR)], catalyst type, and processengineering design. All licensors agree on thenecessity of hydrotreating the feed to removepermanent reforming catalyst poisons and to reducethe temporary catalyst poisons to low levels. Thereare more than 700 reformers worldwide, with a totalcapacity of approximately 11.2 million barrels/day.Approximately 40% of this capacity is located in

TABLE VI

Current and Future Specifications for Diesel Fuel

Year

Specification 2000 2005

Sulfur (ppm) 350 50

Specific gravity (maximum) 0.845 0.825

API (minimum) 36 40

Cetane number 51 54

DistillationT95(1C, maximum) 360 360

Polycyclic aromatic hydrocarbons(PAH wt%, maximum)

11 1



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North America, followed by 20% each in WesternEurope and Asia-Pacific regions.

3.1.1 Reforming ProcessesReforming processes are generally classified intosemiregenerative, cyclic, and CCR. This classification

is based on the frequency and mode of regeneration.The semiregenerative process requires unit shutdownfor catalyst regeneration, whereas the cyclic processutilizes a swing reactor for regeneration in additionto regular reactors. The continuous process permitscatalyst replacement during normal operation. Glob-ally, the semiregenerative scheme dominates reform-ing capacity at approximately 57%, followed by thecontinuous regenerative process at 27% and thecyclic process at 11%. Most grassroots reformers aredesigned to use continuous catalyst regeneration.

The semiregenerative process is a conventionalreforming process that operates continuously over a

period of up to 1 year. Conversion is kept more or lessconstant by raising the reactor temperatures as catalystactivity declines. The cyclic process typically uses fiveor six fixed catalyst beds, similar to the semiregenera-tive process, with one additional swing reactor, whichis a spare reactor. CCR is characterized by highcatalyst activity with reduced catalyst requirements,more uniform reformate of higher aromatic content,and high hydrogen purity. Figure 2 presents a sche-matic diagram of a CCR process. The continuous pro-cess represents a step change in reforming technologycompared to semiregenerative and cyclic processes.

3.1.2 Reforming CatalystsSince the 1950s, commercial reforming catalystshave been essentially heterogeneous monometallic

compounds and are composed of a base supportmaterial (usually chlorided alumina) on whichplatinum metal was placed. These catalysts werecapable of producing high-octane products; however,because they quickly deactivated as a result of cokeformation, they required high-pressure, low-octane

operations. In the early 1970s, bimetallic catalystswere introduced to meet increasing severity require-ments. Platinum and another metal (often rhenium,tin, or iridium) account for most commercialbimetallic reforming catalysts. The catalyst is mostoften presented as 1/16, 1/8, or 1/4 in. Al2O3cylindrical extrudates or beads, into which platinumand other metal have been deposited. In commercialcatalysts, platinum concentration ranges between 0.3and 0.7 wt% and chloride is added (0.11.0 wt%) tothe alumina support (Zor g) to provide acidity.

3.2 IsomerizationIsomerization is an intermediate, fed preparation-typeprocess. There are more than 200 units worldwide,with a processing capacity of 1.5 million barrels/dayof light paraffins. Two types of units exist: C4isomerization and C5/C6 isomerization. A C4 unitwill convert normal butane into isobutane, to provideadditional feedstock for alkylation units, whereas aC5/C6unit will isomerize mixtures of C5/C6paraffins,saturate benzene, and remove naphtenes.

Isomerization is similar to catalytic reforming inthat the hydrocarbon molecules are rearranged, butunlike catalytic reforming, isomerization just con-verts normal paraffins to isoparaffins. The greatervalue of branched paraffins over straight paraffins isa result of their higher octane contribution. The

Stackedreactor

Catalystregenerator

Freshcatalyst

Naphtha feed

Fire heaters

Combinedfeed

exchanger

Net gascompressor

Net H2-rich gas

Fuel gas

LPG

Reformate

FIGURE 2 Flow scheme of a continuous catalyst regenerative naphtha reformer. LPG, liquefied petroleum gas.



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formation of isobutane is a necessary step to producealkylate gasoline or methyl tertiary butyl ether(MTBE). The extent of paraffin isomerization islimited by a temperature-dependent thermodynamicequilibrium. For these reactions, a more activecatalyst permits a lower reaction temperature and

that leads to higher equilibrium levels. Isomerizationof paraffins takes place under medium pressure(typically 30 bar) in a hydrogen atmosphere.

C4isomerization produces isobutane feedstock foralkylation. Platinum or another metal catalyst,alumina chloride, is used for the higher temperatureprocesses. In a typical low-temperature process whereonly aluminum chloride is used, the feed to theisomerization unit is n-butane or mixed butanescombined with hydrogen (to inhibit olefin formation).C5/C6 isomerization increases the octane number ofthe light gasoline components n-pentane and n-hexane, which are found in abundance in straight-

run gasoline. The basic C5/C6isomerization process isessentially the same as butane isomerization.

3.3 Alkylation

Alkylation is the process that produces gasoline-range compounds from the combination of light C3C5 olefins (mainly a mixture of propylene andbutylene) with isobutene. The highly exothermicreaction is carried out in the presence of a strong acidcatalyst, either sulfuric acid (H2SO4) or hydrofluoricacid (HF). The world alkylation capacity stands at

1.9 million barrels/day and new grassroots units havebeen constructed in many refineries worldwide,especially those with FCC units. The alkylateproduct is composed of a mixture of high-octane,branched-chain paraffinic hydrocarbons. Alkylate isa premium clean gasoline blend, with octane numberdepending on the type of feedstocks and operatingconditions. Research efforts are directed toward thedevelopment of environmentally acceptable solidsuperacids capable of replacing HF and H2SO4.Much of the work is concentrated on sulfonatedzirconia catalysts.

3.3.1 Sulfuric Acid ProcessIn H2SO4-based alkylation units, the feedstock(propylene, butylene, amylene, and fresh isobutane)enters the reactor and contacts the concentratedsulfuric acid catalyst (in concentrations of 8595%).The reactor effluent is separated into hydrocarbonand acid phases in a settler and the acid is returned tothe reactor. The hydrocarbon phase is hot waterwashed with a caustic compound for pH control

before being successively depropanized, deisobuta-nized, and debutanized. The alkylate obtained fromthe deisobutanizer can then go directly to motorgasoline blending.

3.3.2 Hydrofluoric Acid Process

In a typical HF process, olefin and isobutane feedstockare dried and fed to a combination reactor/settlersystem. The process is operated at temperaturesattainable by cooling water and at higher pressuresto keep fluid in the liquid state. The reactor effluentflows to a separating vessel, where the acid separatesfrom the hydrocarbons. The acid layer at the bottomof the separating vessel is recycled. Propane with atrace amount of HF goes to an HF stripper for HFremoval and is then defluorinated, treated, and sent tostorage. Isobutane is recycled to the reactor/settler andthe alkylate is sent to gasoline blending.

3.4 Etherification

Etherification results from the selective reaction ofmethanol or ethanol to isobutene. The ether pro-ducts, such as MTBE or other oxygenates, are used ascomponents in gasoline because of their high octaneblending value. The refinery capacity of oxygenateunits is approximately 266,000 barrels/day, withalmost all units associated with alkylation processes.The exothermic reaction is conducted in liquid phaseat 85901C over a highly acidic ion-exchangepolystyrene resin catalyst. The reaction is very rapid

and equilibrium is limited under typical reactionconditions. A combination of catalytic distillation isapplied to remove the product as vapor, therebydriving the reaction to almost 100% conversion. Theetherification process is needed to supply oxygenatesto meet the specifications of reformulated gasoline(minimum 2.7 wt% oxygenate content). In general,MTBE is the preferred oxygenate because of its lowproduction cost and convenient preparation routerelative to those of other ethers.

3.5 Polymerization and Dimerization

Catalytic polymerization and dimerization in petro-leum refining refer to the conversion of FCC lightolefins, such as ethylene, propylene, and butenes, intohigher octane hydrocarbons for gasoline blending.Polymerization combines two or more identical olefinmolecules to form a single molecule, with the sameelements being present in the same proportions as inthe original molecules. Light olefin feedstock ispretreated to remove sulfur and other undesirable



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compounds. In the catalytic process, the feedstockeither is passed over a solid phosphoric acid catalyston silica or comes into contact with liquid phosphoricacid, where an exothermic polymeric reaction occurs.Another process uses a homogenous catalyst systemof aluminum-alkyl and a nickel coordination com-

plex. The hydrocarbon phase is separated, stabilized,and fractionated into LPG and oligomers or dimers.

4. HEAVY DISTILLATE PROCESSING

4.1 Catalytic Hydrotreating

Catalytic hydrotreating is a hydrogenation processused to remove approximately 90% of contaminants,such as nitrogen, sulfur, oxygen, and metals, fromliquid petroleum fractions. These contaminants, ifnot removed from the petroleum fractions as they

travel through the refinery processing units, can havedetrimental effects on the equipment, the catalysts,and the quality of the finished product. In addition,hydrotreating converts olefins and aromatics tosaturated compounds. World capacity of all types ofhydrotreating stands at approximately 38.3millionbarrels/day. Hydrotreating is used to pretreat cataly-tic reformer feeds, saturate aromatics in naphtha,desulfurize kerosene/jet and diesel, saturate aroma-tics, and pretreat catalytic cracker feeds. It alsoincludes heavy gas oil and residue hydrotreating aswell as posthydrotreating of FCC naphtha.

Hydrotreating for sulfur or nitrogen removal is

called hydrodesulfurization or hydrodenitrogena-tion. Hydrotreating processes differ depending onthe feedstock available and the catalysts used. Mildhydrotreating is used to remove sulfur and saturateolefins. More severe hydrotreating removes nitrogenand additional sulfur and saturates aromatics. In atypical catalytic hydrotreater unit, the feedstock ismixed with hydrogen, preheated in a fired heater(3154251C), and then charged under pressure (up to68 atm) through a fixed-bed catalytic reactor. In thereactor, the sulfur and nitrogen compounds in thefeedstock are converted into H2S and NH3. Hydro-desulfurized products are blended or used as catalyticreforming feedstock. Hydrotreating catalysts containcobalt or molybdenum oxides supported on aluminaand less often nickel and tungsten.

4.2 Fluid Catalytic Cracking

Catalytic cracking is the largest refining process forgasoline production, with a global capacity of more

than 14.2 million barrels/day. The process convertsheavy feedstocks such as vacuum distillates, residues,and deasphalted oil into lighter products that are richin olefins and aromatics. There are several commer-cial FCC processes that are employed in worldrefineries with major differences in the method of

catalyst handling. FCC catalysts are typically solidacids of fine particles, especially zeolites (synthetic Y-faujasite), aluminum silicate, treated clay (kaolin),bauxite, and silica-alumina. Zeolite content incommercial FCC catalysts is generally in the rangeof 520 wt%, whereas the balance is a silica-aluminaamorphous matrix. Additives to the FCC processmake up no more than 5% of the catalyst and theyare basically used as octane enhancers, metalpassivators, and SOx reducing agents and are usedin CO oxidation and for gasoline sulfur reduction.

The FCC unit comprises a reaction section,product fractionation, and a regeneration section.

In principle, the reactor (riser) and the regeneratorform the catalyst circulation unit in which thefluidized catalyst is continuously circulated usingair, oil vapors, and steam as the conveying media.Figure 3 presents a schematic of a typical FCCprocess. The operating temperatures of the FCC unitrange from 500 to 5501C at low pressures. Hydro-carbon feed temperatures range from 260 to 4251C,whereas regenerator exit temperatures for hotcatalyst range from 650 to 8151C. Several operatingparameters, mainly temperature, affect overall con-version and it is essential to determine which product

slate is needed so that process conditions are appro-priately selected.

4.2.1 Reaction Section (Riser)A typical FCC unit involves mixing a preheatedhydrocarbon charge with hot, regenerated catalystas it enters the riser leading to the reactor. Majorprocess variables are temperature, pressure, catalyst/oil ratio, and space velocity. Hydrocarbon feed iscombined with a recycle stream within the riser,vaporized, and raised to reactor temperature bythe hot regenerated catalyst. As the mixture movesup the riser, the charge is cracked at approximately

110kPa and the residence time is on the order of1 s. In modern FCC units, almost all crackingoccurs within the riser. The cracking continues untilthe oil vapors are separated from the catalyst in thereactor cyclones.

Cracking reactions are endothermic; the energybalance is obtained by the burning of catalyst-deposited coke in the regenerator. Both primaryand secondary reactions take place during catalytic



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cracking. Primary reactions are the result of thecracking of paraffins, alkyl naphthenes, and alkylaromatics. In general, all cracking reactions arecharacterized by the production of appreciableamounts of corresponding olefins. During the reac-tions, however, approximately 40% of the sulfur inthe FCC feed is converted to H2S, which is easilyremoved. Much of the ongoing research is directed tothe removal of the remaining sulfur in FCC gasoline.

4.2.2 Product Fractionation

Cracked hydrocarbons are separated into variousproducts. The resultant product stream from thereaction section is charged to a fractionating column,where it is separated into fractions, and some of theheavy oil is recycled to the riser. The main FCCproducts are LPG, the gasoline fraction, and light cycleoil. By-products include refinery gases, residue (slurry),and coke. Since the FCC unit is the major source ofolefins in the refinery (for the downstream alkylation

unit or petrochemical feedstock), an unsaturated gasplant is generally considered a part of it.

4.2.3 Regeneration SectionSpent FCC catalyst is regenerated by burning offdeposited coke to carbon dioxide The catalyst flowsthrough the catalyst stripper to the regenerator,where most of the coke deposits burn off in thepresence of preheated air. The carbon content of theregenerated catalyst is generally kept at the lowestlevel to achieve selectivity benefits. Catalyst circula-tion and coke yield determine the temperature at

which the regenerator is operated. Maximum regen-erator temperatures are limited by mechanicalspecifications or sometimes by catalyst stability.The temperature in the regenerator reaches almost6501C due to the exothermic nature of coke-burningreactions. Spent catalyst is continuously removedand fresh catalyst is added as makeup to optimize thecracking process. This added catalyst is in effect themain determinant of catalyst activity. The typical

Reactorproduct

Strippingsection

Riserreactor

Regeneratedcatalyst

Preheater

VGO feed

Regenerator

Flue gas

Spentcatalyst

FIGURE 3 Schematic diagram of fluid catalytic cracking process. VGO feed, vacuum gas oil feed.



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catalyst makeup requirement is approximately 0.1kgper barrel of total feed.

4.3 Hydrocracking

Catalytic hydrocracking of heavy petroleum cuts is

an important process for the production of gasoline,jet fuel, and light gas oils. Some hydrocrackingprocesses also allow the production of a highlypurified residue, which can be an excellent base foroils. The process employs high pressure, hightemperature, a catalyst, and hydrogen. In contrastto FCC, the advantage of hydrocracking is thatmiddle distillates, jet fuels, and gas oils of very goodquality are provided. In general, hydrocracking ismore effective in converting gas oils to lighterproducts, but it is more expensive to carry out.

Hydrocracking is used for feedstocks that aredifficult to process by either catalytic cracking or

reforming, since these feedstocks are usually char-acterized by a high polycyclic aromatic content and/or high concentrations of the two principal catalystpoisons, sulfur and nitrogen compounds. Thesefeedstocks include heavy gas oils, FCC cycle oils,deasphalted oil, and visbreaker or coke gas oil. Theprocess depends largely on the nature of the feed-stock and the relative rates of the two competingreactions, hydrogenation and cracking. Heavy aro-matic feedstock is converted into lighter productsunder a wide range of very high pressures (70140 atm) and fairly high temperatures (4008201C),in the presence of hydrogen and special catalysts.

4.3.1 Hydrocracking ProcessHydrocracking is a two-stage process combiningcatalytic cracking and hydrogenation, wherein heavierfeedstocks are cracked in the presence of hydrogen.The reaction typically involves a reactor section, gasseparator, scrubber for sulfur removal, and productfractionator. The reactor section contains a multi-catalyst bed that can be of the fixed-bed or ebullated-bed type and some employ on-stream catalystaddition and withdrawal to maintain catalyst activity.

4.3.2 Hydrocracking Catalysts

The catalysts used in hydrocracking are all of thebifunctional type, combining an acid function and ahydrogenating function. The acid function is carriedby supports with a large surface area and having asuperficial acidity, such as halogenated aluminas,zeolites, amorphous silica-aluminas, and clays. Thehydrogenating function is carried either by one ormore transition metals, such as iron, cobalt, nickel,ruthenium, rhodium, palladium, osmium, iridium,

and platinum, or by a combination of molybdenumand tungsten. The conventional catalysts of catalytichydrocracking are made up of weak acid supports.These systems are more particularly used to producemiddle distillates of very good quality and also, iftheir acidity is very weak, oil bases. Amorphous

silica-aluminas serve as supports with low acidity.These systems have a very good selectivity in middledistillates and the products formed are of goodquality. The low-acid catalysts among these can alsoproduce lubricant bases.

5. RESIDUAL OIL PROCESSING

5.1 Solvent Deasphalting

Solvent deasphalting (SDA) is a separation processthat represents a further step in the minimization ofresidual fuel. Figure 4 presents a schematic diagramof a typical SDA process. The process takesadvantage of the fact that maltenes are more solublein light paraffinic solvents than asphaltenes. Thissolubility increases with solvent molecular weightand decreases with temperature. There are con-straints with respect to how deep an SDA unit cancut into the residue or how much deasphalted oil(DAO) can be produced. These constraints arerelated to the DAO quality specifications requiredby downstream conversion units and the final high-sulfur residual fuel oil stability and quality.

SDA has the advantage of being a relatively low-

cost process that has the flexibility to meet a widerange of DAO qualities. The process has very goodselectivity for asphaltenes and metals rejection, someselectivity for carbon rejection, and less selectivity forsulfur and nitrogen. It is most suitable for the moreparaffinic vacuum residues as opposed to the high-asphaltene-, high-metal-, high-concarbon-containingvacuum residues. The disadvantages of the processare that it performs no conversion, produces a veryhigh viscosity by-product pitch, and where high-quality DAO is required, SDA is limited in the qualityof feedstock that can be economically processed.

5.2 Visbreaking

Visbreaking is the most widespread process fornoncatalytic mild conversion of residues, with aworld capacity of 3.7 million barrels/day. Theprocess is designed to reduce the viscosity ofatmospheric or vacuum residues by thermal crack-ing. It produces 1520% of atmospheric distillateswith proportionate reduction in the production of



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residual fuel oil. Visbreaking reduces the quantity ofcutter stock required to meet fuel oil specificationsand, depending on fuel oil sulfur specifications,

typically reduces the overall quantity of fuel oilproduced by 20%. In general, visbreakers aretypically used to produce vacuum residues.

The process is available in two schemes: coil crackerand soaker cracker. The coil cracker operates at hightemperatures during a short residence time of approxi-mately 1 min. The soaker scheme uses a soaking drumat 30401C at approximately 1020 min residencetime. The residue is rapidly heated in a furnace andthen cracked for a specific residence time in a soakingzone under proper conditions of pressure and tem-perature. The soaking zone may be within the heateror in a separate adiabatic soaking drum. The cracked

residue leaves the soaking zone after the desired degreeof reaction is reached and is quenched with gas oilto stop the reaction and prevent coking.

5.3 Coking

Approximately 90% of coke production comes fromdelayed coking. The process is one of the preferred

thermal cracking schemes for residue upgrading inmany refineries, mainly in the United States. Theprocess provides essentially complete rejection of

metals and concarbon while providing partial orcomplete conversion to naphtha and diesel. Worldcapacity of coking units is 4.2million barrels/day(approximately 54% of this capacity is in U.S.refineries) and total coke production is approxi-mately 172,000 tons/day. New cokers are designed tominimize coke and produce a heavy coker gas oil thatis catalytically upgraded. The yield slate for adelayed coker can be varied to meet a refinersobjectives through the selection of operating para-meters. Coke yield and the conversion of heavy cokergas oil are reduced, as the operating pressure andrecycle are reduced and, to a lesser extent, as temp-

erature is increased.

5.4 Residue Hydrotreating andResidue FCC

Refineries that have a substantial capacity forvisbreaking, solvent deasphalting, or coking are facedwith large quantities of visbreaker tar, asphalt or

Recycled solvent

Solvent

Feed

Solvent

Exchanger

Solvent makeup

Exchanger

Deasphaltingstep

Heater

Recycled solvent

Exchanger

Compressor

Flashcolumn

Strippingcolumn Exchanger

Steam

Solvent drum

Asphalt conditioning

Dea

sphaltedoil

s

eparation

Heater Solvent

Steam

Deasphalted oil

FIGURE 4 Schematic diagram of a typical solvent deasphalting process.



14/16

coke, respectively. These residues have high viscosityand high organic sulfur content (46 wt%), withprimary consequences reflected in the potential forsulfur emissions and the design requirements for asulfur removal system. Sulfur content is also im-portant from the standpoint of corrosion, which

requires proper selection of design materials andoperating conditions. Other properties of residuesinclude their high heating value due to the high levelof fixed carbon that results in a higher yield of syngasper ton of residue processed. Moreover, residues havelow volatile matter and ash content as well as little tono oxygen content, resulting in low reactivity.

Residue hydrotreating is another method forreducing high-sulfur residual fuel oil yields. Atmo-spheric and vacuum residue desulfurization units arecommonly operated to desulfurize the residue as apreparatory measure for feeding low-sulfur vacuumgas-oil feed to cracking units (FCC and hydrocrack-

ers), low-sulfur residue feed to delayed coker units,and low-sulfur fuel oil to power stations. Twodifferent types of processing units are used for thedirect hydrotreating of residues. These units are eithera down-flow, trickle phase reactor system (fixedcatalyst bed) or a liquid recycle and back-mixingsystem (ebullating bed). Economics generally tend tolimit residue hydrotreating applications to feedstockscontaining less than 250 ppm nickel and vanadium.

Residue FCC (RFCC) is a well-established ap-proach for converting a significant portion of theheavier fractions of the crude barrel into a high-

octane gasoline-blending component. In addition tohigh gasoline yields, the RFCC unit producesgaseous, distillate, and fuel oil-range products. TheRFCC units product quality is directly affected by itsfeedstock quality. In particular, unlike hydrotreating,RFCC redistributes sulfur, but does not remove itfrom the products. Consequently, tightening productspecifications have forced refiners to hydrotreatsome, or all, of the RFCCs products. Similarly, inthe future, the SO

x emissions from an RFCC may

become more of an obstacle for residue conversionprojects. For these reasons, a point can be reachedwhere the RFCCs profitability can economically

justify hydrotreating the RFCCs feedstock.

6. TREATING PROCESSES

6.1 Hydrogen Production

Refineries are experiencing a substantial increase inhydrogen requirements to improve product qualityand process heavy sour crudes. Hydroprocessing and

saturation of aromatics and olefins will accelerate thedemand for hydrogen within the refinery. Catalyticnaphtha reforming alone is not able to meet refineryhydrogen requirements. A survey on world refiningindicated that the capacity of supplementary refineryhydrogen, produced mainly by steam reforming of

methane, reached 337 million m3/day (11,880 millionft3/day-MMcfd) in 2002 compared to 110 mil-lionm3/day in 1990. There is a growing recognitionthat there will be a significant future shortage ofrefinery hydrogen supply. Specific hydrogen produc-tion units, such as steam methane reformers or thosecarrying out partial oxidation of heavy residues, willhave to be built.

6.2 Residue Gasification

The gasification of refinery residues into clean syngasprovides an alternative route for the production of

hydrogen and the generation of electricity in acombined turbine and steam cycle. Compared tosteam-methane reforming, gasification of residues canbe a viable process for refinery hydrogen productionwhen natural gas price is in the range of $3.754.00/million British thermal units (MMBtu). The largestapplication of syngas production is in the generationof electricity power by the integrated gasificationcombined cycle (IGCC) process. Consumption ofelectricity in the modern conversion refinery isincreasing and the need for additional power capacityis quite common, as is the need to replace old capacity.The design of a residue gasification plant requires a

careful matching and integration of the variousprocess steps to ensure optimum performance of thewhole system. In general, the IGCC plant consists ofseveral steps: gasification, gas desulfurization, and acombined cycle. The technologies of the gasificationand the combined cycle are well known; the innova-tion, however, is their integration in order tomaximize the overall IGCC efficiency.

6.3 Aromatics Extraction

BTX aromatics are high-value petrochemical feed-stocks produced by catalytic naphtha reforming and

extracted from the reformate stream. Whether or notother aromatics are recovered, it is sometimesnecessary to remove benzene from the reformate inorder to meet mandated specifications on gasolinecomposition. Aromatics production in refineriesreached 1.2 million barrels/day in 2002. Most newaromatic complexes are configured to maximize theyield of benzene and paraxylene and sometimesorthoxylene. The solvents used in the extraction of



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aromatics include dimethylfrmamide, formylmorpho-line, dimethylsulfoxide, sulfolane, and ethylene glycols.

6.4 Sweetening

Sweetening is the removal of contaminants such as

organic compounds containing sulfur, nitrogen, andoxygen; dissolved metals and inorganic salts; andsoluble salts dissolved in emulsified water frompetroleum fractions or streams. A variety of inter-mediate and finished products, including middledistillates, gasoline, kerosene, jet fuel, and sour gases,are sweetened. Treating can be accomplished at anintermediate stage in the refining process or just beforethe finished product is sent to storage. Choices of atreating method depend on the nature of the petroleumfractions, the amount and type of impurities in thefractions to be treated, the extent to which the processremoves the impurities, and end-product specifica-

tions. Treatment materials include acids, solvents,alkalis, oxidizing agents, and adsorption agents.

6.5 Sulfur Recovery

Sulfur recovery converts hydrogen sulfide in sourgases and hydrocarbon streams to elemental sulfur.Total sulfur production in world refineries reachedapproximately 64,000tons/day in 2002 compared toapproximately 28,000 tons/day in 1996, correspond-ing to a yearly growing recovery rate of 20%. In otherwords, in 2002 an average refinery recovered 0.8 kgsulfur from one processed barrel of crude oil

compared to less than 0.4kg sulfur recovered in1996. This indicates the increasing severity of opera-tions to meet stringent environmental requirements.The most widely used sulfur recovery system is theClaus process, which uses both thermal and catalyticconversion reactions. A typical process produceselemental sulfur by burning hydrogen sulfide undercontrolled conditions. Knockout pots are used toremove water and hydrocarbons from feed gasstreams. The gases are then exposed to a catalyst torecover additional sulfur. Sulfur vapor from burningand conversion is condensed and recovered.

6.6 Acid Gas Removal

Amine plants remove acid contaminants from sourgas and hydrocarbon streams. In amine plants, gasand liquid hydrocarbon streams containing carbondioxide and/or hydrogen sulfide are charged to a gasabsorption tower or liquid contactor, where the acidcontaminants are absorbed by counterflow aminesolutions [i.e., monoethanol amine (MEA), diethanol

amine (DEA), methyl diethanol amine (MDEA)]. Thestripped gas or liquid is removed overhead and theamine is sent to a regenerator. In the regenerator, theacidic components are stripped by heat and reboilingand are disposed of, and the amine is recycled.

7. ENVIRONMENTAL ANDFUTURE ISSUES

7.1 Environmental Issues

Refiners are faced with many environmental, econom-ic, and operational issues. Environmental legislation isa growing concern, driving changes in product specifi-cations, product markets, and refinery operating prac-tices. Strict product quality specifications and severeemission and discharge limits have economic impacton the average refiner. In the near future, the following

environmental trends will continue to grow, but theywill not create significant changes in oil consumptionpatterns: (1) the production of clean transportationfuels according to new specifications and (2) refineryoperation within strict emissions regulations.

The configuration of many refineries has changedsubstantially, mainly due to the declining quality ofcrude oil supply and environmental regulations. Inretrospect, refinery changes brought about by thevariations in crude supply and composition wereevolutionary, whereas environmental regulations wererevolutionary.

7.1.1 Clean Transportation FuelsSince 1990, government agencies have imposedstrict environmental restrictions on transportationfuels to improve product quality specifications. Fuelreformulation is being discussed all over the world.Automotive manufacturers are demanding lowergasoline sulfur levels and lower driveability indices.Refiners must improve air quality by delivering cleanproducts that minimize emissions of toxic andhazardous hydrocarbons. Gasoline and diesel formu-lations have been already changed in many countriesand will change even more in the coming years.

Refining is faced with huge investments to meetnew stringent specifications for sulfur, aromatics, andolefin content. Gasoline sulfur reduction is centeredaround the FCC unit employing feed pretreatment orgasoline posttreatment. The reduced demand forethers, such as MTBE in gasoline for oxygenatecontent, necessitates the utilization of branchedparaffin isomer products of alkylation and isomer-ization. For diesel fuel, this means a sulfur content



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less than 30 or even 15ppm, an increase of the cetanenumber, a reduction in polyaromatic content, andT95point limitation. To fulfill all these legislative andregional requirements, refiners must either revampexisting units or invest in new hydroprocessing andhydrogen production units.

7.1.2 Refinery EmissionsRefiners must comply with various environmentalregulations to reduce all types of pollutants in theirwaste gas as well as wastewater systems. Mostconcerns involve the emissions of SO

x, NO

x, CO,

hydrocarbons, and particulates. The oxides arepresent in flue gases from furnaces, boilers, andFCC regenerators. Tail gas treatment and selectivecatalytic reduction units are being added to limit SO2and NO

x emissions. Water pollutants include oil,

phenol, sulfur, ammonia, chlorides, and heavymetals. New biological processes can be used toconvert H2S o r S Ox from gaseous and aqueousstreams. Spent catalysts and sludges are also ofconcern to the refinery in reducing pollution. Somespent FCC catalysts can be used in cement but othercatalysts that contain heavy metals need specialtreatment before proper disposal.

7.2 Future Refining Issues

World refining has been adapting to ongoing productchanges and environmental challenges. Transporta-tion fuels with approximately free sulfur will be

needed to satisfy the demand of the automotiveindustry to reduce emissions from internal combus-tion engines. There will be an increased demand foralkylate and isomerate gasoline as well as deep-desulfurized diesel. This will increase the hydrogencontent in gasoline, enhance combustion, and reducethe levels of carbon dioxide emissions.

The introduction of fuel cells as a feasible way tofuel zero-emission vehicles is a major challenge to oilcompanies and refiners. Virtually every major auto-motive manufacturer has a fuel-cell program andmost claim production readiness by 2005. Refinersneed to adapt to this technology in the future,

especially regarding new fuels needed for fuel cells.Fuel-cell vehicles need hydrogen generated on-boardor carried in either compressed or liquid form. Thelatter calls for a global hydrogen infrastructure. Theuse of hydrocarbons and specifically gasoline togenerate hydrogen offers many economic advantages

such as the availability of a ready-made globalfueling infrastructure.

The huge technological challenges associated withthe transfer to a hydrogen economy necessitate anefficient and better use of hydrocarbon resources tocompete with renewable energy sources. Refiners

need to enhance and integrate their business withchemical production and power generation. In thelong run, the refinery will produce not just fuels, butalso chemicals and electricity.

SEE ALSO THEFOLLOWING ARTICLES

Coal Preparation Oil and Natural Gas Drilling

Oil and Natural Gas Exploration Oil and NaturalGas: Offshore Operations Oil Pipelines OilRecovery Petroleum System: Natures DistributionSystem for Oil and Gas

Further Reading

Aitani, A. (1995). Reforming processes. In Catalytic NaphthaReforming (G. Antos et al., Eds.), pp. 409436. Dekker,New York.

Farrauto, R., and Bartholomew, C. (1997). Fundamentals ofIndustrial Catalytic Processes, pp. 519579. Blackie Academicand Professional, London.

Gary, J., and Handwerk, G. (2001). Petroleum RefiningTechnology and Economics. 4th ed. Dekker, New York.

Heinrich, G. (1995). Introduction to refining. In PetroleumRefining (J. P. Wauquier, Ed.), pp. 365413. Editions Technip,Paris.

Hoffman, H. (1992). Petroleum and its products. In RiegelsHandbook of Industrial Chemistry (J. Kent, Ed.), 9th ed.,pp. 490496. Van Nostrand Reinhold, New York.

Le Page, J. P., Chatila, S., and Davidson, M. (1992). Resid andHeavy Oil Processing. Editions Technip, Paris.

Maples, R. (2000). Petroleum Refinery Process Economics. 2nded. PennWell Books, Tulsa, OK.

Martino, G., and Wechem, H. (2002). Current Status and FutureDevelopments in Catalytic Technologies Related to Refiningand Petrochemistry, Review and Forecast Paper, 17th WorldPetroleum Congress, Rio de Janeiro, Brazil, September 2002.

Meyers, R. (1997). Handbook of Petroleum Refining Processes.2nd ed. McGraw-Hill, New York.

Penning, T. (2001). Petroleum Refining: A Look at the Future,Hydrocarbon Processing, February, pp. 4546.

Silvy, R. (2002). Global refining catalyst industry will achieve strongrecovery by 2005, Oil & Gas Journal, pp. 4856. September 2,2002.

Speight, J., and Ozum, B. (2002). Petroleum Refining Processes.Dekker, New York.

Stell, J. (2002). Worldwide refining survey. Oil & Gas Journal,December 23, 2002, pp. 6870.

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