PETROLEUM AND PETROCHEMICAL

Petra

meaning rock

oleum

meaning oil

sweet

relatively little sulfur

sour

substantial amount of sulfur

petroleum

can be described as thick, flammable, yellow-to-black mixture of gaseous, liquid, and solid hydrocarbons

Colonel Edwin Drake (1859)

drilled the first successful oil well in Titusville, Pennsylvania because they were looking for a source of kerosene to be used for lighting fuel

President Gerald Ford

led the Project Independence, which is a ten-year plan to build 150 coal-fired power plants and 200 nuclear plants

crude oil

often called black gold

separation

oil is separated into its constituents by distillation

conversion

the various hydrocarbons are then chemically altered to make them more suitable for their intended purposes

purification

hydrogen sulfide gas is converted to sulphur, which is sold in liquid form to fertilizer manufacturers

Physical Separation Processes, Chemical Catalytic Conversion Processes, Thermal Chemical Conversion Processes

Classification of specific processes

Crude Oil Desalting, Crude distillation, Vacuum distillation, Solvent Deasphalting, Solvent Extraction, Solvent Dewaxing

Processes under Physical Separation Processes

Crude Oil Desalting

removal of salt in crude oil through electrostatic water separation, where crude oil temperature should be in the range of 49-54 deg. C

Crude distillation

receives high flow rates, hence its size and operating cost are the largest in the refinery; removal of undesirable components like sulphur, nitrogen, and metal compounds, and limiting the aromatic contents

Vacuum distillation

further distill the residual oil from the CDU, and must be performed at absolute pressure as low as 10-50 mmHg so as to limit the operating temperature to less than 350C; increases the relative volatility of the key components

Solvent Deasphalting

only physical process where carbon is rejected from heavy petroleum fraction such as vacuum residue; propane in liquid form is usually used to dissolve the whole oil, leaving asphaltene to precipitate

Deasphalted Oil

has low sulphur and metal contents since these are removed with asphaltene; also called as “Bright Stock” and is used as feedstock for lube oil plant

Solvent Extraction

lube oil stock is treated by a solvent, which can dissolve the aromatic components in one phase (extract) and the rest of the oil in another phase (raffinate)

phenol and furfural

solvent used in solvent extraction

Solvent Dewaxing

raffinate is dissolved in a solvent and the solution is gradually chilled, during which high molecular weight paraffin (wax) is crystallized, and the remaining solution is filtered

lube oil

extracted and dewaxed resulting oil

methyl ethyl ketone (MEK)

solvent used in solvent dewaxing

Catalytic Reforming, Hydrotreating, Catalytic Hydrocracking, Catalytic Cracking, Alkylation, Isomerization

Processes under Chemical Conversion Processes

Catalytic Reforming

a special catalyst is used to restructure naphtha fraction (C6-C10) into aromatics and isoparaffins, where the produced naphtha reformate has a much higher octane number than the feed, this reformate is used in gasoline formulation and as a feedstock for aromatic production (benzene-toluene-xylene, BTX)

platinum metal supported on silica or silica base alumina

catalyst used in catalytic reforming

octane number

a value used to indicate the resistance of a motor fuel to knock; octane number decreases with an increase in the carbon chain length, but increases with carbon chain branching

Hydrotreating

one of the major processes for the cleaning of petroleum fractions from impurities such as sulphur, nitrogen, oxy-compounds, chloro-compounds, aromatics, waxes and metals using hydrogen; catalyst used is selected to suit the degree of hydrotreating and type of impurity

cobalt and molybdenum oxides on alumina matrix

commonly used catalyst in hydrotreating

Catalytic Hydrocracking

for higher molecular weight fractions such as atmospheric residues (AR) and vacuum gas oils (VGOs), cracking in the presence of hydrogen is required to get light products

zeolite catalyst (for cracking function) and rare earth metals supported on alumina (for the hydrogenation function)

catalyst used in catalytic hydrocracking

kerosene, jet fuel, diesel and fuel oil

main products of catalytic hydrocracking

Catalytic Cracking

also called Fluid Catalytic Cracking; main player for the production of gasoline

zeolite base (for cracking function)

catalyst used in catalytic cracking

Vacuum Gas Oils (VGO)

feed to FCC

Alkylation

process in which isobutene reacts with olefins such as butylene to produce a gasoline range alkylate

sulphuric acid or hydrofluoric acid

catalyst used in alkylation

Isomerization

process in which low octane number hydrocarbons (C4, C5, C6) are transformed to a branched product with the same carbon number to produce high octane number products; one main advantage is to separate hexane before it enters the reformer, thus preventing formation of benzene, which produces carcinogenic products on combustion with gasoline

Pt-zeolite base

main catalyst used in isomerization

Delayed Coking, Flexicoking, Visbreaking

Processes under Thermal Chemical Conversion Processes

Delayed Coking

this process is based on the thermal cracking vacuum residue by carbon rejection forming coke and lighter products such as gases, gasoline and gas oils; vacuum residue is heated in a furnace and flashed into large drums where coke is deposited on the walls of these drums, and the rest of the products are separated by distillation

Flexicoking

most of the coke is gasified into fuel gas using steam and air, the burning of cole by air will provide the heat required for thermal cracking

gases, gasoline, and gas oils with very little coke

products of flexicoking

Visbreaking

mild thermal cracking process used to break the highly viscosity and pour points of vacuum residue to the level which can be used in further downstream processes; in this case, the residue is either broken in the furnace coil (coil visbreaking) or soaked in a reactor for a few minutes (soaker visbreaker)

gases, gasoline, gas oil, and unconverted residue

products of visbreaking

Ammonia, Plastics, Petroleum by-products, Rubber, Dyes, synthetic detergents, and fabrics, Lubricants, Paraffin wax, Tar, Asphalt/bitumen

Application of Petroleum

Haber process

ammonia is produced by this process

ammonia

a source of nitrogen in agricultural fertilizers

nylon, polystyrene, polyvinyl chloride plastics

most successful petroleum-based plastics

mineral oil and petrolatum

petroleum by-products that are used in many creams and topical pharmaceuticals

rubber

obtained from plants which is a natural elastomer and is used in making tires

dyes, synthetic detergents, and fabrics

contain petroleum distillates such as benzene, toluene, and xylene

lubricants

greases and adds viscosity

paraffin wax

a solid derivable from petroleum that consists of a mixture of hydrocarbon molecules

tar

used in preserving wooden vessels against rot

asphalt/bitumen

a derivative of petroleum which has primary use in road construction

Transportation, Industrial Power, Heating and Lighting, Lubricants, Petro-chemical Industry, Use of by-products

six main uses of petroleum

Air Pollution Hazards, Water Pollution Hazards, Soil Pollution Hazards, Oil Spills, Acid Rain

environmental impacts of petroleum