Petroleum and gas processing

WASEEM AKHTAR

NFC-IET-MULTAN

petroleum

• Crude oil that consist of different hydro carbon compounds and many other organic and inorganic compound, this word is extracted from latin word petra =rock oleum= oil . it is a naturally occurring, yellow-to-black liquidfound in geological formations beneath the Earth's surface, which is commonly refined into various types of fuels.

• It consists of hydrocarbons of various molecular weights and other organic compounds.[4] The namepetroleum covers both naturally occurring unprocessed crude oil and petroleum products that are made up of refined crude oil. A fossil fuel, petroleum is formed when large quantities of dead organisms, usuallyzooplankton and algae, are buried underneath sedimentary rock and subjected to both intense heat and pressure.

A thick, flammable, yellow-to-black mixture of gaseous, liquid, and solid hydrocarbons that occurs naturally beneath the earth's surface, can be separated into fractions including natural gas, gasoline, naphtha, kerosene, fuel and lubricating oils, paraffin wax, and asphalt and is used as raw material for a wide variety of derivative products. (American Heritage Dictionary)The word petroleum comes from the Latin petra, meaning “rock,” andoleum, meaning “oil.”The oil industry classifies "crude" by the location of its origin and by its relative weight or viscosity ("light", "intermediate" or "heavy"). The relative content of sulfur in natural oil deposits also results in referring to oil as "sweet," which means it contains relatively little sulfur, or as "sour," which means it contains substantial amounts of sulfur.

history

• Red Indian used the oil in seepages as a medicine, burning bushes.iraqi used crude to joint jewellry by adhesive from crude

• Iraqi made first distilation unit of crude oil from wine distiilary sold oil as commercial in 12th cenntury. In 18th century english made first refinery. In first world war gasoline made to run aeroplane engines. In 1930 markete of petrolium was established

Origin of petroleum

• It is closely related to theory of vegitation . In old time trees at the shore area burried and under high pressure and temperature bacterial decomposition they convert into petrol. The composition of petrol is c and H,s,o,Ni, vandium.

• It is customery use a term preved reserve which means well defined petroleum wells which are recoverable by present production method

• Tar sands used to produce heavy crud due to sand

• Oil shale the oil in tar sands mixed with sand but shale the oil is combined rock material known as kerogen

Oil shale

• Oil shale, also known as kerogen shale, is an organic-rich fine-grained sedimentary rock containing kerogen (a solid mixture oforganic chemical compounds) from which liquid hydrocarbons called shale oil (not to be confused with tight oil—crude oil occurring naturally in shales) can be produced. Shale oil is a substitute for conventional crude oil; however, extracting shale oil from oil shale is more costly than the production

Tar sands

• Oil sands are either loose sands or partially consolidated sandstone containing a naturally occurring mixture of sand, clay, and water,saturated with a dense and extremely viscous form of petroleum technically referred to as bitumen (or colloquially tar due to its similar appearance, odour, and colour). Natural bitumen deposits are reported in many countries, but in particular are found in extremely large quantities in Canada

Constituents of petroleum

• Crude petroleum contain thousand of different chemical substances including solid ,liquid and gas , methane and asphalt. API study has found 200 different compound

•

API = 141.5 - 131.5SP.GRAVITY

Aliphatics or openchain

• These have formula CnH2n+2. The series of large fractions are found in crude. These are straight run .and distillate directly from crude and known as n- parafins. These have poor antiknocking properties. These have strong pouring point (the liquid tempt at which liquid become solid). These are saturated hydrocarbond

Formula Name CAS-Number Structural Formula Chemical Classification

CH4 Methane 74-82-8 Alkane

C2H2 Ethyne 74-86-2 Alkyne

C2H4 Ethene 74-85-1 Alkene

C2H6 Ethane 74-84-0 Alkane

C3H4 Propyne 74-99-7 Alkyne

C3H6 Propene - Alkene

C3H8 Propane - Alkane

C4H6 1,2-Butadiene 590-19-2 Diene

C4H6 1-Butyne - Alkyne

C4H8 Butene - e.g. Alkene

C4H10 Butane - Alkane

C6H10 Cyclohexene 110-83-8 Cycloalkene

C5H12 n-pentane 109-66-0 Alkane

C7H14 Cycloheptane 291-64-5 Cycloalkane

C7H14 Methylcyclohexane 108-87-2 Cyclohexane

C8H8 Cubane 277-10-1 Cyclobutane

C9H20 Nonane 111-84-2 Alkane

C10H12 Dicyclopentadiene 77-73-6 Diene, Cycloalkene

C10H16 Phellandrene 99-83-2Terpene, Diene

Cycloalkene

C10H16 α-Terpinene 99-86-5Terpene, Cycloalkene,

Diene

C10H16 Limonene 5989-27-5Terpene, Diene,

Cycloalkene

C11H24 Undecane 1120-21-4 Alkane

C30H50 Squalene 111-02-4 Terpene, Polyene

C2nH4n Polyethylene 9002-88-4 Alkane

Iso paraffin.

• these are branched chain material perform better performance in internal combustion engines than n- parafine. They areformed by catalytic reforming, alkylation, polymerisationor isomerisation. Only small amounts exsist in crude

Olefin or alkene

• These are not found in crude oil but produce in cracking. These are unstable molecules, these are improve anti knocking quality of gasoline. They are polymerized and oxidised. Many petrochemicals are produced from them e.g etylene, propylene,butylene

Aromatic compound

• This series has chemical formula CnH2n. They are less instable and reactivity. These are second abundant compound in crude e.g. methylcyclopentane, cyclohexane. This group are good fuels and higher molecular weight

Lesser component

• Sulfur has undesirable component of cude . It has object able odor , equipment corrossionand environmental hazard . So it is requirement to eliminate the sulfur from products of crude

Refinary process

• The crude from beneath of earth surface is sent to refinery. In petroleum refinarygeneration of usage able and scalable fractions and products from crude oil by distillation process or by chemical reaction under the effect of heat and pressure.

• Synthatic crude oil produced from tar sand known as bitumen heavier oil (shale oil ) used as feed stocker in some refineries

• Crude petroleum is mixture of many organic materials at different temperature. They can be separated into different fractions by distillation .crude oil obrained from the resorvoir is darked to light brown color liquid . It is known as conventional petroleum . This material has difficult to flow has high API gravity and difficult to flow .

Distillation

• Crude oil is converted into different fraction by distillation process. The common methods are

• Atmospheric disilation

• Vacuum distilation

• Aezotropic and extractive distilation

•

• Crude oil is known as feed stock . By distilationdifferent fractions are obtained

Crude feed stock

Light naphtha 1- 150 CGasoline 1- 180 CHeavy naphtha 150 -205 CKerosene 205 – 260 C stove oil 205 - 270CLight gas oil 260 – 315 CHeavy gas oil 315 – 425 CLubricating oil 400 C Vacuum gas oil 425 CResidua 600 C

Rectifying section

Stripping section

furnace

• The temperature of distillation is below the 345C because thermal decomposition of petroleum conctituents take place at 350C. The temperature above 425C is taking place in vacuum ditilation . Asphalt is obtained from residue. It is obtained by solvent extraction of residue.

• Sweet and sour mean in refinary is free from sulpher and with sulfer content respectivly

• Crude contain mercuptants and H2S

Desalting and dewatering

• Crude oil from well contains gases water and dirt . Thus pretreatment is done before sent to refinary

• To remove dirt, water and gas by seperatorsand gravity separator.

• Desalting is done by water washing and sediment technique

NAPHTHAHYDROPHINEATMOSPHERIC

DISILATION

UNIT LIGHT FEED STOCK

GAS PLANT

GAS PLANT PETROCHEMICAL

H2SO4

ALKYLATION

KEROSENE HYDROPHONE

JET FUEL

DIESEL OIL

CATALYTIC HYDROCRACKER

CATALYTIC REFORMING

MID

DITILATION

HYDROFIRE

KEROSENE

HEAVY OIL

GASOLINE

FUEL OIL

LPG

160C

160 -230

230 -300 C

340

RESIDUA

SOLVENT DESPHALTING

ATMOSPHERIC RESIDUA FOR HEAVY FEED STOCK

VACUUM STILL CLAY TREATMENT

GASOLINE

CATALYTIC CRACKING

SOLVENT EXTRACTION

LUBE WAXES

GREASE

AROMATIC OIL

ASPHALT

COKER

VACUUM HYDRO TREATER

340 -470

470 -560

PRECIPITATOR

REFINING

• Refining is done to convert the products accourding to demands . When the products fraction is produced from crude oil. There are a number of products are into fractions are present e.g gasoline, diesel oil, lubricants, waxes

Distillation

• The separation of different fractions from the crude due to their different boiling point difference from the crude or feed stock is called distillation.

• Types of distillation

1. Atmospheric distillation

2. Vacuum distillation

3. Aezotropic distillation

Atmospheric distillation

• The crude oil is introduced in distillation column by flow pipe . The heating unit is known as atmospheric pipe still . A heater or furnace is provided to distillation column

• Distillation column is divided into two section

• Rectifying section and stripping section

• Rectifying is top side of column and bottom side stripping section with refluxes

• The crude feed stock is entered in heater or furnace where the feed is converted liquid to vapor phase. Furnace remain under pressure then a vapor of forth form stream is produced. This stream is sent to distillation unit . Where the vapors are moved in rectifying section and liquid steam is moved at the bottom side of column(stripping) .column walls is internaly insulated with fire bricks

Vacuum distillation

• Vacuum distillation is done to separate less volatile product such as lubricants from petrol because these material are cracked when subjected to more heat in atmospheric distillation . The boiling point of liquid is done in atmospheric pressure is limited temperature 350C at which residue decompose or cracked

• Operating condition for vacuum distillation are 7-13 kPa. So that to minimize the pressure fluctuation in vacuum tower

• Heavy gas oil is produced at the top of tower at 150C

• Lubricants is produced at 250 -350 C

Aezotropic or extractive distillation

• It is used to produce various liquid fraction . In aezotropic distillation different chemical ability of compounds to caused one or both component of mixture boil at temperature other than on expected . The addition of non indigenous component form a aezotropic mixture that lower the boiling point and facilitate separation of liquid. The third component added should be cheap ,stable and non toxic and readily recoverable from components

• For successive distillation entrainer used in one component separate into two liquids phase on cooling it is direct recovered . If it is not possible aezotropic entrainer is that component which boiling point 10 – 40 C below that of component

cracking

• Breaking of larger molecule of petroleum products into small molecules in presence of zeolite catalyst

• Types of cracking

• Thermal cracking

• Catalytic cracking

• Steam cracking

Thermal cracking

• C7H15.C15H30.C7H15 C7 H16

• +

• C6H12:CH22

•

+

• C14H28:CH

HEAVY GAS OIL

GASOLINE

GASOLINE (ANTIKNOCK)

RECYCLE STOCK

Thermal cracking

• This process is best for heavier crude

• Heavier crude to lighter crude is produced from this process

• In refineries heaver crude is produced during off seasons of demand

• This method is best to handle residue of distillate

• Braking of residue occur at high temperature in absence of catalyst

• At elevated temperature in absence of catalyst visbreaking ,delayed coking and fluid coking occur

• Principle of cracking • Higher boiling petroleum stock lower boiling products

• Free radical chain reaction

• free radical +hydrocarbon stable end product

• Heating treatment,mediocure heat treatment for low residential time

• Cracking naphtha aromatic(cracking) aliphatic aromatic(condensation) aromatic higher aromatic(condensation)

• In kerosene gasoline is included which is too volatile. In first world war gasoline is obtained from Kerosene by thermal cracking unit . The heavier component is converted into gasoline

• The bottom side of thermal cracking production of lower boiling salable materials ,asphaltic material and unwanted coke remain in residua

Thermal cracking is caused of vis breaking

• Viscosity of oil is reduced during the cracking operation . Thermal cracking is oldest cracking process now near to obselete . Residua is blended with lighter heating oil to produce fuel oil . By reducing the vicosity then more value able light heating oils are obtained that is required for blending to meet fuel oil specifications . The pour point is reduced of waxy residua. Thermal cracking is done at 455 -510C and 345 – 2070 Kpa at heating

Cont. thermal cracking

• The primary products of this process is gasoline ,lighter gasolene, heavy gas oil. Heavy gas oil is additonal feed for catalytic cracking unit.

• Crude oil passed through furnance where it is heated to 480 C under pressure 690 Kpa . The heating coil in furnance breaking the viscosity of feed .the over head product of this section is low quality gasoline and light oil at the bottom .

• This heated oil sent to flash chamber the liquid product is cooled with gas oil and sent to fractionater.

• The yield of hevy gas oil distilate and residual tar of reduced viscosity . A quench oiil used to terminate the reaction .this product is unstable on sudden cooling and gives olefins in form of gum

Furnace

Vacuum residua

flasher

Fraction tower

Vacuum fraction ator

Low quality gasoline

Heavy gas oil

Light gasoline

gasoline

Heavy gas oil

480 C

690 kpa

Thermal cracking unit or destructive distillation

Or Coker naphtha

Coking

• Coking is a series of thermal cracking process and is used to convert the non volatile heavy fed stock into lighter distillate product .the product of coking is gas oil ,naphtha ,fuel oil ,gas oil ,and coke

• Gas oil is primary product of this process while coke is used as a fuel , electrode ,and production of metallurgical coke

• DELAYED COKING PROCESS• FLUID COKING PROCESS• FLEXI COKING PROCESS

• It is semi continuous process in which heat is transferred to large soaking or coking drum in which residance time is important factor to complete cracking reaction

• The feed of vacuum residue and thermal process residue is used . The feed stock is introduced the product fractionator . At the bottomside recycle of heavy product are heated in furnance which outlet temperature is 480 -515 C.

• The heated feed stock then enter one of pair of coking drum ,where cracking drum where cracking reaction continue . The cracked products leave as overhead materials and coke deposits form inner surface of drum and cooled by water . The coke drum temperature is 415-450 C with pressure 103 -621 kpa overhead product go to the fractionators. Where naphtha are heated oil is recovered . The non volatile material is combined with preheated fresh feed and returned to furnace before coming porous coke . Coke remain in coke drum for 24 hrs and removed hydraulically

FRACTIONATOR

HEATER

NON PARATIVE

COKING DRUM SOAKER

OPENING COKING DRUM SOAKER

GAS

NAPHTHAGASOLINE GAS OIL

HEAVY OIL

DELAYED COKING ROCESS

COKE

Fluid coking

• In fluid coking there are two vessels a reactor and burner . Coke particles are circulate between reactor and burner . The reactor fluidized coke particales and sream is introduced at the bottom of reactor to fluidized bed

Fluidized coking

•

steam

Fluidized bed reactor

burner

Flue gas

coke

air

Heavy stock

Over head product

Excess coke

Makeup coke

Flexi coking

• It is continuous process . It is similar to fluid coking process but difference is that in gasification section excess coke can be gasified to produce refinery fuel gas. Flexi coking process in which excess coke is made is reduced in view of gradual incursion of heavier feed stock into refinery operation . Such feed stock are not good for production of higher yield of coke in thermal or catalytic process

Scrubber

HeaterGasifier

Reactor product to fractionators

recycle

bituminous

steam

Purgecoke

Fines remover

Coke gas to sulfur

Coke fines

coolerSteam generator

air

steam

Catalytic cracking

• Catalytic cracking is similar to thermal cracking with a difference presence of catalyst

• catalyst

• In firstly catalytic cracking process acid catalyst were used but now a days low alumina catalyst that is amorphous solid contain 87% silica and 13% alumina while alumina catalyst contain 25% alumina and 75%silica in spherical form pellets that are used in fixed bed and moving bed fluid bed reactors

• Catalytic process is used today moving bed unit and fluidized bed unit

• Theramafor catalytic cracking (TCC) and fluidized bed catalytic cracker(FCC) is fluidized bed , the fcc units is classified as bed or riser depends upon the major fractions of cracking reaction occurs .

• The hot oil feed is contacted with catalyst in bed or riser of reactor as cracking reaction progress deactivation of catalyst starts by formation coke on the surface of catalyst . The catalyst and hydrocarbon vapors are separated mechanically

• Oil remaining on the catalyst is removed by steam stripping before catalyst enter the regenerator . The oil vapors are taken overhead to a fractionators tower the oil vapors are taken overhead to a fractionation tower for separation into stream having the desired boiling range.

• regenerative the spent catalyst flows into regenerative and reactive by burning off coke deposits with air . Regenerative temperature is carefully controlled prevent catalyst deactivation by over heating carbon is burn off and flow the controlled ai carefully catalyst are seperated by cyclone seperator and electrostatic precipitator is used. How ever some units used steam stripping

Fixed bed process

• Several reactors in series with loading catalyst in which feed stock is input . Feedstock flows through catalyst bed discontinuous the feed stock and removed the coke from catalyst by burning the catalyst and reused in reactor . In fluidized catalytic cracking the size of particales of catalyst peelets are 70 microns which behave as a fluid with vapor.

• The fluidized catalyst circulated continuously between the reaction zone and regeneration zone and transfer the heat regenerator to reactor ( separator)

• Dense phase of fluidised catalytic bed in the reactor vessel there is most of cracking occurein the reactor bed . The extent of reaction is controlled by depth of bed and temperature so high rate of cracking occur in riser attempt was made to regulate the reaction by controlling riser conditions

• The zeolite catalyst for cracking is used by refinaries

• Reactor works as separator as well as cracking performing

• It separate the catalyst and hydrocarbon vapor

• Feed is injected in fluidized cracker by spray nozzles , the fresh feed and recycle feed is preheated by waste heat boiler ,enter in the base of feed riser where they are mixed with hot generated catalyst . The heat of heated catalyst is enough to rise the temperatur of cracking .

• This mixture of catalyst and hydrocarbons vapors are sent to separator, cracking is started when vapors contacted with high temperature catalyst . Hydro carbons vapors are sent to factionator while catalyst is regerated in regerator and sent back to riser

• The leaving catalyst from reactor is known as spent catalyst , by steam stripping remove from the catalyst absorbed hydrocarbon .

• Regenerator temperature is controlled by 620 -845C

In the regenerator burn the coke on catalyst or either by carbon monoxide to carbon dioxide technique was used in older regenerator . The flue gases from the regenerator sent to waste heat boiler.

In new technology deposited carbon is stem reformed and produce hydrogen and carbon monoxide and carbon dioxide and convert the carbon monoxide in to CO2 and passed through w.h.b

regenerator

reactor

air

fractionator

Recovery gas

gasoline

Light gas oil

Heavy gas oil

Slurry oil

Slurry decantation

Fresh feed

Regeneratorcatalyst

Slurrysettler

Spent catalyst

w.h.b

To final dust collection

F.C.C UNIT

Steam

Hydro cracking

• Hydro cracking is done >350C in which pressure held 1000 – 3000 psi and conversion of feed stock to lower boiling products

• During the hydro cracking lower yield gaseous compounds are obtained such as methane , ethane, propane less desirable than gasoline

• In first preheating stage hydro cracking process the main feed stock to hydrocarbons and ammonia and hydrogen sulfide by hydrogenation

• Hydro cracking is done by lowering concentration of N2 and S is 50ppm at 340 –390C and 1500 -2500 psi for 1- 1.5 contact time

• In this stage used catalyst may be nickel ,tungsten , molybdenum, sulfide

• Thiols R-SH +H2 RH+H2S

• Disulfide R-S-S-R +H2 RH+RH+H2S

• THIOPEN

S

H2 nC4H10 H2S

Most of hydro cracking is completed in secondary stage. Hydrogen sulfide ,ammonia and low boiling product is removed . NH3 and H2S are removed in first stage catalyst and the remaining oil which is low in nitrogen and sulfer content is passed through second stage catalyst is done 300 – 370C and 100 – 2500psi and 0.5 -1 hr contact time .

Conversion of gasoline is done with catalyst high boiling product is combined with fresh feed and recycled over catalyst until it is completed

• The catalyst for second stage is also bifunctional catalyst containing hydrogenating and acid component . Metal such as nickel , molybdenum , tungsten and palladium is used . Catalyst are regenerated after 2.5 – 3 years

• hydro treating

• The catalytic process converts sulfur and N2 containing hydrogenation catalyst are Ni , palladium ,platinum ,cobalt and iron . By temperature increasing hydrogenation is reversed . Hydrogenation is reversed . Hydro treating is done in reactor at 300-345C at 500-1000psi. The reaction take place in vapor phase.

• After passing through oil is cooled and separate from excess hydrogen recycled through reactor and sent to stripper tower where H2S is formed by hydrogenation reaction . Steam is produced by vapor stream and sent back to stripper tower. Catalyst is regenerated in several regenerations

Catalytic hydrocracking

• Hydrogenation is done in catalytic hydro cracking in petroleum refinery

• Hydro cracking is done due to several following reasons

1. Demands for petroleum products has shifted to high demand for gasoline, diesel, and jet fuel as compared to other fuels product usage

2. By product hydrogen at low cost and large amounts has become available from catalytic reforming operations

3. Environmental issues due to sulfur limits and aromatics compound in motor fuels has increased

In hydro cracking process convert the lignite into gasoline

By improving the new catalyst modern hydro cracker distillate come into ages operation could be done at low pressure than earlier units . In this way demand for higher octane unleaded gasoline

Jet fuels and lower sulfur content diesel fuel is

permoted

• Advantage of catalytic cracking

1. Better balance of gasoline and distillate production

2. Greater gasoline boiling range naphtha yields

3. Improved gasoline pool octane quality and senstivity

4. Production of relatively high amounts of isobutene in butane fraction

5. Supplementing of fluid catalytic cracking to upgrade heavy cracking stocks, aromatics ,cycle oils and Coker oil to gasoline jet fuels ,and diesel

• In catalytic cracking cracked the parrafins by using gas oil as charge stocks . Where as hydro cracker uses more aromatics oils and Coker distillates as a feed. zeolite cracking catalysts improve the yield of gasoline in this process .

• Residue is difficult to cracked by this catalyst to overcome this difficulty residue is blended with fuel and burns in cracker in this way residue crack into aromatic components

Hydro cracking process

1. GOFFING PROCESS

It is fixed bed regenerative process , a molecular sieve of catalyst is installed here . The process may be done in single stage or two stage depends upon the size of unit and production the operating condition for the process are in the range of 660 – 785 F and 1000 – 2000 psig . For the most sauitable condition single stage is preffered

• The fresh feed is mixed with makeup hydrogen and recycle gas are passed through heater to first reactor . If the feed is not hydrotreated,there is a guard reacror is provided which is impregnated with catalyst cobalt and molybedinum on silica –aluminia convert the organic sulfur and nitrogen compound into H2S ,ammonia and hydrocarbon to protect catalyst of following reactor

• The hydro cracking reactor is operated at sufficiently high temperature to convert the 40 -50%by volume of reactor effluent to material boiling below 400 F . The reactor effluent goes through heat exchanger to high pressure separator where hydrogen rich gas is separated and recycle to the first stage for mixing both make up hydrogen and fresh feed

• The liquid product from the separator is sent to a distillation unit .where gasoline and lighter gases and naphtha as overhead product

• Jet fuel and diesel oil stream is recovered as liquid fuel.

• The bottom of fractionators unit is taken as feed of second stage reactor system .

• The unit can be operated to produce gasoline and lighter products or to maximize the jet fuel or diesel fuel.

• The bottom of stream from fractionators is mixed with recycle hydrogen from second stage and sent through a furnace to second stage reactor. Here the temperature is maintain to bring the total conversion of the unconverted oil from the first stage and second stage recycle to 50 -70% by volume per pass . The second stage product is combined with the first stage product prior to fractionation

• Both the first and second stage reactors contains several beds of catalysts . The major reason for having separate beds is provided for injection cold recycled hydrogen between the beds help to maintain a more uniform utilization of catalyst

• When operating hydrocarbons for total conversion of distillate feeds to gasoline the butane and heavier liquid yields are generally from 120 to 125 vol% of fresh feed.

feed

H2 recycle H2 make upgas

C1-C4

naphtha

diesel

H2 make upH2 recycle

REFORMING

• When high octane number gasoline is needed to produce and improving the gasoline octane number by fractions . Straight run gasoline has low octane number and by this process improve the high octane number and by this process improve the high octane number. All these are done in thermal reforming.

Reforming types

1. Thermal reforming

2. Catalytic reforming

3. Steam reforming

thermal reforming

• The process similar to thermal cracking in which cracking converts heavier oil into gasoline while in reforming converts gasoline lower octane is converted into higher octane at high temperature

• Thermal reforming is less effective and less economical than catalytic reforming converts low octane grade gasoline into high grade octane gasoline

• Thermal reforming reforms octane number 65-80 while catalytic reforming reforms 95-105

Catalytic reforming

• Catalytic reforming is conducted in presence of hydrogen over hydrogenation ,dehydrogenation ,catalyst used in this process are same in catalytic cracking and similarly contain naphtha ,hydrocracker naphtha contain naphthenic compound

• Dehydrogenation is done in catalytic reforming and hydrogen gas is produced in large quantities, hydrogen is recycled through reactors where reforming is done by chemical reaction . In catalytic reforming by product is H2

• Catalytic reforming is carried out by feed of naphtha treating with H2(removing of Sand N)

• The mixture of H2 and naphtha to a furnance it is heated at temperature of 450 -520 C and then passed through fixed bed catalytic reactor and hydrogen pressure is 350 – 2700Kpa. The catalyst used are platinum rehnium and alumina based . Platinum promotes the dehydrogenation ,hydrogenation reaction . Non platinum catalyst are used in regenerative process for feed stock containig S in series of reactors

Isomerisation or polymerisation

• Isomerisation is used to additional feed stock for alkylation unit for isobutene product or higher octane fractions for gasoline blending for( pentane and hexane) . The latter application is useful in the production of reformulated gasoline by increasing octane number while converting or removing benzene. Iso butane is also used for synthesis of methyl tetra butyl ether (MTBE)as additive

• That maintaining octane rating in gasoline instead of tetra ethyl lead

• Initially aluminum chloride was the catalyst used to isomerizes butane, pentane, and hexane. Since then supported metal catalysts have been developed for use in high temperature process that operate at 370-480C and 300-750psi . Where as aluminum chloride catalyst is used in fixed bed reactor . Normally platinum is used as a catalyst in fixed bed reactor

The reaction is occurred between 40-480C and 150-100Psi depends upon particular feed stock and processes

ALKYLATION the combination of olefins+paraffins to form isoparaffins in the term of alkylation. Alkylation is desirable blend stock because it has a relatively high octane number and dilute the total aromatic contents. Reduction of olefins in gasoline blend stock by alkylation also reduces tail pipe emission

• In refinery practice butylene are alkylated by reaction with isobutane -octane . Alkylate is composed of a mixture of isoparafins which octane number vary with the olefins which they were made . Butylene produces the highest octane number. Propylene the lowest and amylene the intermediate value

• Propylene , butylene or amylene are combined with isobutene in the presence of an acid catalyst such as sulfuric acid or hydrofluoric acid at low temperature 1-40C and pressure 102- 1035Kpa. Both of these catalyst are used in refinaries . The acid is used to form emulsion with reactants . Butene consumes less acid than propylene

Polymerization

• In this process olefin gases are converted into higher molecular weight liquid product and suitable gasoline polymerization product are obtained . Propylene and butylene from cracking process selective olifins dimers trimerand tetrament production .

• This oligomerisation done with these products C4 –C12 are liquid polymerized saturated material that cannot effective

1. Thermal polymerization

2. Catalytic polymerization

1. Thermal polymerization

Thermal polymerization is not effective as catalytic polymerization but has advantage that cannot be included to react catalyst . The process consist of vapor phase cracking e.g. propane and butane followed by prolong period at high temperature 510-595C for reaction to proceed near combustion

• Olifins are polymerized by means of acid catalyst . Olifins rich feed in presence of H2SO4 copper pyrophosphate and phosphoric acid at 150 -220C and 150 – 1200Psi depends upon feed stock requirement . Phosphate is used in polymerization unit.

• TREATING

• Since the original crude oil contain some sulfur compound and gasoline has sulfur compound including H2S,mercuptants, sulfides, disulfides and thiophene removing of S is called sweating product

Hydro treatment

Alkali treatment

Acid treatment

ALKALI TREATMENT

• Hydro treatment is important technique for all types of petroleum product and sauitable to evaluate H2S and mercuptant compound .

• RSH is removed by soda treating

• H2S+2NaOH Na2S+2H2O

• RSH+NaOH NaSR+H2O

• 4NaSR+O2+2H2O RSSR+4NaOH

• This method is effective for low concentration steam generation method is used to remove mercuptants such as gasoline, low boiling solvents . The caustic is regenerated by steam blowing in stripper tower . The nature and concentration of mercuptants to be removed by quantity of process

ACID TRATMENT

• This treatment of petroleum product is done in petroleum industry . Acids such as hydrofluoric acid, hydrochloric acid and nitric acid and H2SO4 are used in refine Kerosene and lubricants . Acid treatment is done for cracked gasoline and paraffinic kerosene

CLAY TREATMENT

• A tower contain clay pellets . Clay absorb the impurity from petroleum fraction. Clay after removing recovered by burnt the absorbed matters . It is effective for lubricants , gum forming in gasoline. Clay removing the asphalt material .

SOLVENT TREATMENT

• SOLVENT TREATMENT

SOLVENT EXTRACTION

SOLVENT DEWAXING

SOLVENT TREATMENT

• The solvent is used in extraction process include propane and creslyic acid ,2,2dichlorodiethyl ether , phenol , furfural , SO2, benzene and nitrobenzene . Solvent processing is done for lubricants at the end of crude . Solvent extraction process is done to separate the impurity for purification of gasoline, kerosene , diesel oil , e. g propane desphalting is removed by extraction process that comes from vacuum distillation process ,removing asphalt from crude oil

dewaxing

• In dewaxing process solvent is benzene,methylethyl ketone, methyl isobutyl, ketone , propane ,petroleum naphtha , ethylene dichloride , methylene chloride , sulfur dioxide and n- methylpyrollidineone.

PROPANE DESPHALT SHOWN BELOW

HEAVY FEED STOCK

PROPANELIQUID

EVAPORATOR STRIPPER

FLASHERSTRIPPER

PROPANE RECOVERY

GAS PROCESSING

• The gas stream is produced during petroleum refining usually contain many noxious constituents that have adversed effect on the use of gas for other purposes e.g fuel or petrochemical feed stock and some degree of cleaning is required

• Gas processing is fall into three category 1. Removal of gaseous impurity 2. Removal of particular impurity3. Ultrafine cleaning

• The operation or the need to produce a pure gas stream . Because there are many variables in gas streaming treatment

• Several factors must be considered 1. Types and concentration of contaminations in

the gas2. The degree of contamination removal is desired 3. Selectivity of acid gas removal reqired4. The temperature , pressure , volume , and

composition of gas to be processed

5. CO2 and H2S ratio in gas

6. The desirability of sulfur recovery on account of process economics

Process selectivity indicates that the performance with which the process remove one acid gas component relative performance to another

e.g some process desighn are fixed to remove H2S

• Thus it is important to consider the process selectivity for H2S compare to CO2 removal .

LIQUID PETROLEUM GAS (LPG)

• Specific hydrocarbons such as propane ,butane , pentane ,this mixture exist in gaseous state under atmospheric state under atmospheric ambient condition but can converted to liquid state under moderate pressure and ambient temperature . This product is known as LPG.

• The presence of ethane in LPG must be avoided because of instability of this lighter hydrocarbon to liquefy under pressure and ambient temperature and its tendency to show abnormal high pressure in LPG contaner

• The pressure of pentane is avoided in LPG because this hydrocarbon is liquefied state and ambient temperature and pressure can be seperated as liquid state gasoline

• LPG gases precipitated asphaltic and resinous material from crude residue while lubricating oil constitution remains in solution . All liquefied gases is possess this property to some extent propane and butane are used to desphalt residual lubricants because their low relative cost

GASOLINE

• The naphtha fraction from crude oil distillation is ultimately used to make gasoline . The two streams are isolated early in refining scheme so that each can be refined separately for optimum blending in order to achieve reformed specification

• Gasoline is complex mixture of hydrocarbon that boils below 200C .

• The H/C constituents in this boiling range are those that have C4-C12 composition

• Gasoline can very widely in composition even those have same octane number

• Because of difference in composition of various gasoline . Gasoline blending is necessary . The physical process of blending the composition is simple but determination of each component is difficult

• Aviation gasoline usually used in an air crafts with boiling range 38 -170C than automobile gasoline 0- 200C . Some amount of butane is added to vaporize the gasoline in winter

• In air crafts vapor pressure must be changed as temperature of fuel change occur but not boiling in fuel tank . Gasoline combustion is smooth and fit for precise combustion cycle, ignite with minimum spark

• The extra pressure pulses resulting from spontaneous combustion are audible above normal sound of engine are abnormal combustion

• To stabelize octane number minimum knocking , isooctane are normal heptane in proper rate are used as anti knocking

SOLVENTS

• Naphtha is refined and unrefined product mixture of refinary and is obtained from fractional distillation . Mainly used in paint industry , dry cleaning , and rubber industry

• Turpentine is used in paint industry which is abundantly found in naphtha

KEROSENE

• Kerosene is straight run product petroleum fraction that boils 205 -260C. C12 – C15 is kerosene containing product ,low portion of aromatic and unsaturated H/C with low S –content in kerosine

• The other important fuels are Diesel fuel , Jet fuel, coming from Kerosene fraction

• Fuel oil is classified as distillate fuel oil and Residual fuel oil

1. Distillate Fuel Oil Distillate fuel oil is vaporized and condense during distillation process . It has definite boiling range and not contain asphaltic material

2. Residual fuel oil

Fuel oil is contain residue from crude distillate .Domestic stove oil and diesel heavy fuel is obtained from this fraction

• Ship , marine , are obtained from residual fuel

LUBRICATING OIL

• Lubricating oil distinguish from other fractions of crude oil and obtained from boiling range >400 C . They are high viscous

• Lubricating oil is classified as in motor lubricants , aviation lubricants, and turbine oil

• Lubricating oil is used in intermittent service and show least possible variation viscosity with respect to temperature and must be changed at frequently interval to remove foreign matter collected during service .

• The stability of such oil is therefore of less importance than stability of oil used in continuous service for prolonged period without removal . The importance of lubricating oil work in the engine maintain its constant temperature and avoid its abnormal shut down

wax

• Waxes are classified in two classes paraffin wax in distillate and micro crystalline waxes residue

• The melting point not related to boiling point because waxes contain hydrocarbons of different chemical structure .

• Waxes grades are related to different melting point and oil content paraffin waxes is a solid crystalline mixture of straight chain normal hydrocar bon range C20- C30and higher

• These are solid at 25C while petroleum jelly contain solid and liquid H/C wax producing by wax sweating

• Recrystallization process is first wax producing method in which slackes or raw wax is warmed to a temperature where wax became liquid and pure wax is collecting by dropwiseat bottom . Leave behind higher melting point residue

Dewaxing processes

• Commonly there are two different methods are for producing wax

1. Solvent dilution

2. Chilling to crystallize the wax and filter

Wax crystals are formed by chilling through walls of scraped surface chiller oil . Wax solvent seperated by rotary vacuum filter . Solvent used for dewaxing are naphtha ,propane ---

• ---, SO2 , acetone –benzene , tricolor ethylene ,ethylene dichloride –benzene (barisol), methyl ethyl –ketone –benzene(benzol), methyel –n butyl ketone , methyel n-propyl-ketone and other solvents are N-methyel –pyrrolidinone, dichloroethane – methyelene di chloride and propylene –acetone.

• Solvent dewaxing can be applied to lighter intermediate and heavy lubricating oil distillates but each distillates produce different kind of wax and each is actually a mixture of number of waxes the wax obtained from light parrafin distillates consist of a series of parrafin waxes .The m.p is 30-70 and hard crystals form on cooling.The wax contain 60-90 c hard and small crystals called microwaxes.

Propane process

• Propane is dilute form is evaporated by reducing pressure so as chill the sluary to desired filtration temperature and rotary pressures filtration is applied formation of solid waxes ,n parrafine is refrigerated and separated by filtration this method is used low viscosity lubricants which remain in liquid state at low temperature . The oil of transform are hydrolic oils.

• Silicon carbonate manufacturing from which accetylene is produced.

• Coke produced from low quality crude oil is mixed with coal and burns as fuel .

• Coke is used in fluidized bed combustors or gasifiers for power generation.

Centrfuging seperation

• Centrfuging separation of petroleum form residue by centrifuging dewaxing . Crude oil in dissolved in naptha and chilled -18C or lower which causes separate wax then it is sent to battery of centrifuge when wax is separated from liquid . Similarly the modren method is used to collect HCL of normal parrafines.

Catalytic dewaxing

• Catalytic dewaxing is hydro cracking process operated at temperature 280-400C and 300-1500 psi . The condition for specific dewaxing operation depends upon nature of feed back stock and product are pour point required . The catalyst is used to crack the normal paraffin's. Another catalytic dewaxing process is involved selective cracking for normal parrafine and those paraffin that minor branching in chain catalyst is regenerated by mono oxidation treatment.

• A catalytic dewaxing process can be used to dewax a variety of lubricants base stock it has potential to replace solvent dewaxing.

Asphalts

• This is residual of distillation that can be produced by propane desphalting . Asphalt can be made softener by blending hard asphalt with extract obtained from solvent treatment of lubricating oil .

• Soft asphalts can be converted into hard asphalt by air oxidation . Cutback asphalt are mixture in which hard asphalt has been diluted with light oil to permit application as a liquid without heating .

• They classified as rapid medium and slow curing depends on volatility of diluents which govern the rate of evaporation .

• Asphalt can be emulsified with water to permit application without heating . Such emulsion are normal oil in water . They are used road making soil stability , water proofing.

Coke

• This residue is obtained by destructive distillation (coking residue)

• Petroleum coke is employed for number of purposes the principle use is carbon electrode manufacturing ,for AL refining, which requiring high purity carbon that low in ash and free sulphur.

• Coke is employed in manufacturing of carbon brushes.

FURNACE

REACTOR

LOW TEMPERA-TURE FLASH

HIGH TEMPER-ATUTE FLASH

NAPHTA

DISTILATION