1.Also called as rock oil. Naturally occurring oil and the colour varies from black to brown. Either petroleum oil flows out itself (due to underground pressure) Or it is pumped out mechanically. COMPOSITION OF PETROLEUM OIL: Typical composition of petroleum is as Element %age carbon84-87hydrogen11-15nitrogen0.1-1.5oxygen0.3-1.5sulphur0.1-3

2. Difference between origin of petroleum oil and coal Formations Petroleum oil is formed from sea plants and animals decaying under strongly reducing conditions.Coal is formed mainly from land plants decaying under mildly reducing condition Nature of seams: Coal seams remain static while oil seams can migitate under the effect of pressure and temperatures 3. Origin of Petroleum a) Widely accepted theories for origin of petroleum are Carbide Theory: Hydrocarbons present in petroleum are formed by the action of water or inorganic carbides Inoganic carbides are formed by reaction of metal & carbon under high temperature and pressure inside the earth Ca + 2C = CaC2 Al + C = Al4C3 These carbides would react with underground water to form hydrocarbons CaC2 +2 H2O = Ca(OH)2 + C2H2 (acetylene) Al4C3 + 12 H2O= 4Al(OH)3 + 3CH3 (methane) 4. Contd. Lower hydrocarbons then undergo hydrogenation and polymerization.C2H2 + H2 = C2H4 +H2 = C2H6 3C2H2 = C6H6 (benzene) 3C2H4 = C6H12 (cyclohexane) Flaws In Carbide Theory: This theory fails to explain the following facts. presence of nitrogen and sulphur compounds. presence of chlorophyll. presence of optically active compounds Due to these flaws this theory was rejected. 5. Englar Theory Suggested by Englar in 1900 that petroleum is of animal origin. Formed by the decay and decomposition of marine animals under high pressure and temperature. SO2 was given by volcano deside the sea-side kills the fish and other marine animals which go in to piling. Hundreds of year causes animalto decompose under high pressure and temperature to form petroleum this theory was supported by the facts as destructive decomposition of fish, oil and other animals fats under high P & T, gives product similar to petroleum presence of brine and sea water along with petroleum 6. Presence of fossils in the petroleum areas. However this theory fails to explain the presence of chlorophyll in petroleum as well coal deposit in the vicinity of oil field. 7. Modern Theory According to modern theory Petroloeum is believed to formed from the decomposition of marine animals as well as of vegetable organism of prehistoric forests. prehistoric forests and sea animals got burried under the crust of earth due to some earthquakes and upheavals . High T & P in earth crust causes the degradation of biological matter in to petroleum. This theory succesfully explain the flaws present in previous theoris like Presence of brine & coal in yhe vicinity of petroleum Presence of chlorophyll & N and S compoounds 8. Detection Of petroleum Deposits Detection of petroleum include the steps as following. Visual method Geophysical method Geological method Drilling method Visual method include oil seepages at the surface of earth. Geophysical method include measuremet of density, elasticity magnetic & electrical properties of the rocks Geological method include the measurement of age & nature of rocks inside the earths crust Drilling is the final test when the petroleum deposit has been proved by the earlier methods. 9. Contd. Petroleum always occur along with gas (natural gas) After drilling,both natural gas and oil flow up through the pipe under pressure. Ater the decreasing of pressure, residual oil is sucked by a pump or pressure is created by injecting compressed gas or high preesure water through bored pipe to drill it out. Oil well containing both oil& gas= wet well. Oil well containing gas = dry well. 10. Pretreatment Of Oil At Oil field Oil and gas from field are separated. Natural gas is compreesed to liquify it used for house hold purposes. Petroleum oil is made free of water sediments and salts Then dissolved gases are removed from it by a process called stabilization. Then sent to oil refineries for separation in to various petroleum products by distillation and other operations Mechanical Method: oil is subjected to centrifuging, filtration and settling after heating it to 120-160 C at 6-8 atm pressure. 11. Contd. Physico-chemical method: In this method emulsion breakers but they are costlyand cause corrosion and sludge formation. Electrical dehydration method: 10% water is added to crude and heated before passing through an electrical dehydrator. In dehydrator two concentric metal plates are electrode in which 30000 volt is supplied separating water from crude. 1st dehydrator => T= 90-95C , P=6.8atm 2nd dehydrator => T= 80-90C, P=5.5-6atm. 12. Stabilization Of Crude Oil Stabilization is the method to remove dissolved gasses fromcrude oil. Gas must be removed to avoid breathing loss(loss of gasoline, if gas is not removed from oil during pre-refining). Breathing loss is due to change of humidity of ambient air and day and night tempereture during filling and emptying of crude tanker. Breathing loss= 0.4-0.75 kg/m3 permonth. 13. Classification of Petroleum Depending on nature, hydrocarbon are classified as Paraffinic crude petroleum oil Naphthenic crude petroleum oil Asphaltic (aromatic) crude oil Mixed crude oil paraffins have general formula Cn H2n+2 are saturated hydrocarbons (where n=1 to 35) such as methane, propane, pentane. Naphthenes having general formula CnH2n are saturated ring compounds (where n=1 to 9) e.g cyclobutane (C4H8), cyclohexane (C6H12) etc. Another hydrocarbons having same general formula CnH2n but straight chain is called olefin. E.g ethylene (C6H6), toulene (C6H5CH3) etc. 14. Contd. Aromatics have general formula C6H2n-6 (n>6) contain 6 carbon atoms in the form of hexon shaped ring and are unsaturated ring compounds Lower hydrocarbons in these groups are generally gases, intermediate ones are liquids and higher ones are solids/semi solids. 15. Uses of Petroleum Products Liquified petroleum gas(LPG): Mixture of propane and butane Domestic and industrial fuel Al so called refinary gas. Gasoline (petrol): Fuel for sparking ignition & internal combustion engine Dry cleaning of clothes Naphtha: Used as paint thinner, solvents, blending of motor fuel Used in production of H2 by its steam reforming. Used as a fuel gas in steel plants. 16. Jet fuel: Fuel for jet planes, motor engines. Diesel: Fuel for diesel engine Gas oil: Gassified for fuel gas production Fuel for industrial funace Used as a blend for heavy fuel oil. Lubricating Oil: Used as lubricants in machines and engines. Petrolatum: Also a lubricant used as a base material for grease manufacture Light fuel oil: Used as a fuel in industrial furnace. 17. Heavy fuel oil: Used as furnace fuel after blending with light fuel oil Cracked to produce gasoline, diesel, gas, light fuel etc. Bitumen or Tar: Used for road making as a binder And for moisture proof coating Wax: Used for making candles Used for match stick coating, 18. Queries?