Petroleum and Natural Gas

Concept Explanation

Petroleum and Natural Gas

Petroleum and Natural Gas: Petroleum and natural gas were formed from the remains of tiny marine organism that died millions of years ago.

Process of formation of petroleum and natural gas: Tiny marine organisms died and settled on the ocean floor. With passage of time, this layer of dead organisms were covered beneath sediments. Enormous heat and pressure transformed the remains to petroleum and natural gas. Rising through porous rocks like sandstone, petroleum and natural gas reached a layer of impermeable rock and trapped below it. Petroleum and natural gas are extracted by drilling through the impermeable rocks. Petroleum is a complex nature of solid, liquid and gaseous hydrocarbon. The process of separating various constituents of petroleum is known as refining and carried out in refinery. It is heated to 400°C and introduced in fractionating column. Vapours of petroleum rise inside the fractionating column cool and condense at different heights, depending on their boiling paints and collected in different trays.

Products obtained are:

  • 1. Below 30°C: petroleum gas (used as a domestic fuel in its liquefied from)
  • 2. 30-120°C: Petrol used as a fuel in automobiles, dry cleaning .
  • 3. 120-180°C: Naphthalene  used as a petrochemical .
  • 4. 180-250°C: Kerosene (used as a fuel in lamps and stoves)
  • 5.  250-350°C: Diesels (used as a fuel in heavy motor vehicles and generators)
  • 6. 350-500°C:  lubricating oil used as oil in machinery and grease.
  • 7. Above 500°C: Fuel for ships and power stations and asphalt (used for making roads)
  • Natural Gas: It is a naturally occurring hydrocarbon gas mixture consisting mainly of methane and some other hydrocarbons as well. Uses of natural gas:

  • 1.  Used for generation of electricity .
  • 2.  CNG used as fuel in automobiles as well as domestic fuel.
  • 3.  Production of ammonia .
  • 4.  Used to produce hydrogen .
  • 5.  Manufacture of steel, glass, plastic etc.
  • Refining of petroleum : Petroleum is a mixture of several hydrocarbons. It is a foul - smelling brown black liquid. It also contains water, salt and rocky materials. It can not be used in this crude form either as a fuel or as a basic material to produce other useful components. Before being put to use, it has to be purified and refined. The process of separating the various components of petrol from one another is known as the refining of petroleum. This is done by a process called fractional distillation which is based on the fact that the different components of petroleum have distinctly different boiling points. They are seprated in a large fractionating column. Crude oil is pipped to the refinery from a well. It is washed with acid and alkali solutions to remove the basic and acidic impurities respectively. Crude oil is now heated about 673 K and fed at the base of fractionating column. All the components of expect asphalt are in the vapour state. As the mixture of hot vapours rise up in the column, it begins to cool. The components with the highest boiling point condense later.

           The components obtained at different heights in order from the bottom are asphalt, lubricating oil, paraffin wax, fuel oil, diesel, kerosene, petrol and petroleum gas.

            Products obtained on fractional distillation of crud :

  • Asphalt :  Asphalt is a black and sticky substance. It is used for making the surface of roads. It does not burn readily.
  • Paraffin wax : It boils at above 673 K . It is obtained by the fractionation of residual oil. It is used for making candles, vaseline, grease, polishes etc. It is also used for water proofing paper cartons.
  • Lubricating oil : Its boiling range is 622 K to 673 K. It is obtained by the fractionation of residual oil. It is used for lubricating machinery.
  • Fuel oil : The boiling range of fuel is 573 K to 623 K. It is used in industries to heat boilers and furance. It is a better fuel than coal because its burns completely leaving behind no ash, whereas coal burns producing a large amount of ash, where as coal burns producing a large amount of ash which has to be removed regularly.
  • Diesel Oil : Its boiling range is 573 K to 623 K. It contains straight - chain alkanes with the number of carbon atoms varying from 16 - 20. It is used in cars, trucks, buses and locomotives. It is also used to run pumps in fields and in electric generator.
  • Kerosene : Its boiling range is 423 K to 573 K . It contains straight- chain alkanes with 11- 16 carbon atoms. It is used for domestic purpose for lighting petromax, lanterns, lamps, stoves etc. It is also used for making oil gas. A special grade of kerosene is used as aviation fuel in aeroplane jet engines.
  • Petrol : Its boiling range is 343 K to 393 K. It is also called gasoline. It contains paraffin from pentane to dodecane. It is used as a fuel in two - wheelers, three- wheelers, and cars. It is also used as a solent for the dry- cleaning of clothes.
  • Residual oil:  The residual oil obtained from the primary distillation of  petroleum is known as reduced crude. Reduced crude id distilled in vaccum to yield bitumen as residue. Bitumen is largely used in making road surfaces, and also for coating cables to provide electrical insulations.
  • Sample Questions
    (More Questions for each concept available in Login)
    Question : 1

    Which of the following is source of renewable energy ?

    Right Option : C
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    Question : 2

    Assertion : Petrol is more volatile than diesel oil.

    Reason : Petrol condenses near the top of the column than diesel oil.

    Right Option : B
    View Explanation
    Question : 3

    Formation of petroleum is ___________

    Right Option : A
    View Explanation

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