Lesson Notes By Weeks and Term - Junior Secondary School 2

Crude oil and Petrochemicals I









Crude oil and Petrochemicals I

What is 'Crude Oil'

Crude oil is a naturally occurring, unrefined petroleum product composed of hydrocarbon deposits and other organic materials. Crude oil can be refined to produce usable products such as gasoline, diesel and various forms of petrochemicals. It is a nonrenewable resource, also known as a fossil fuel, which means that it can't be replaced naturally at the rate we consume it and is therefore a limited resource.



Crude oil is typically obtained through oil drilling, where it is usually found alongside other resources, such as natural gas (which is lighter, and therefore sits above the crude oil) and saline water (which is denser, and sinks below). It is then refined and processed into a variety of forms, such as gasoline, kerosene, and asphalt, and sold to consumers.

Although it is often called "black gold," crude oil has ranging viscosity and can vary in color to various shades of black and yellow depending on its hydrocarbon composition. Distillation, the process by which oil is heated and separated in different components, is the first stage in refining.



Petrochemicals, also called petroleum distillates, are chemical products derived from petroleum. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as corn or sugar cane.

The two most common petrochemical classes are olefins (including ethylene and propylene) and aromatics (including benzene, toluene and xylene isomers). Oil refineries produce olefins and aromatics by fluid catalytic cracking of petroleum fractions. Chemical plants produce olefins by steam cracking of natural gas liquids like ethane and propane. Aromatics are produced by catalytic reforming of naphtha. Olefins and aromatics are the building-blocks for a wide range of materials such as solvents, detergents, and adhesives. Olefins are the basis for polymers and oligomers used in plastics, resins, fibers, elastomers, lubricants, and gels.

Primary petrochemicals are divided into three groups depending on their chemical structure:

Olefins includes ethylene, propylene, and butadiene. Ethylene and propylene are important sources of industrial chemicals and plastics products. Butadiene is used in making synthetic rubber.


Aromatics includes benzene, toluene, and xylenes. Benzene is a raw material for dyes and synthetic detergents, and benzene and toluene for isocyanates MDI and TDI used in making polyurethanes. Manufacturers use xylenes to produce plastics and synthetic fibers.


Synthesis gas is a mixture of carbon monoxide and hydrogen used to make ammonia and methanol. Ammonia is used to make the fertilizer urea and methanol is used as a solvent and chemical intermediate.


Refining of Crude Oil

  1. Distillation

Modern distillation involves pumping oil through pipes in hot furnaces and separating light hydrocarbon molecules from heavy ones in downstream distillation towers – the tall, narrow columns that give refineries their distinctive skylines.


  1. Cracking

Since the marketplace establishes product value, our competitive edge depends on how efficiently we can convert middle distillate, gas oil and residuum into the highest value products. Refinery convert middle distillate, gas oil and residuum into primarily gasoline, jet and diesel fuels by using a series of processing plants that literally “crack” large, heavy molecules into smaller, lighter ones. Heat and catalysts are used to convert the heavier oils to lighter products using three “cracking” methods: fluid catalytic cracking (FCC), hydrocracking (Isomax), and coking (or thermal-cracking).


  1. Treating (Removing Impurities)

The products from the Crude Units and the feeds to other units contain some natural impurities, such as sulfur and nitrogen. Using a process called hydrotreating (a milder version of hydrocracking), these impurities are removed to reduce air pollution when our fuels are used.


  1. Reforming

Octane rating is a key measurement of how well a gasoline performs in an automobile engine. Much of the gasoline that comes from the Crude Units or from the Cracking Units does not have enough octane to burn well in cars. The gasoline process streams in the refinery that have a fairly low octane rating are sent to a Reforming Unit where their octane levels are boosted. These reforming units employ precious-metal catalysts – platinum and rhenium – and thereby get the name “rheniformers.” In the reforming process, hydrocarbon molecules are “reformed” into high octane gasoline components. For example, methyl cyclohexane is reformed into toluene.


Product testing


A final and critical step is the blending of our products. Gasoline, for example, is blended from treated components made in several processing units. Blending and Shipping Area operators precisely combine these to ensure that the blend has the right octane level, vapor pressure rating and other important specifications. All products are blended in a similar fashion.

Quality Control

In the refinery’s modernly-equipped Laboratory, chemists and technicians conduct quality assurance tests on all finished products, including checking gasoline for proper octane rating. The reforming process actually removes hydrogen from low-octane gasoline. The hydrogen is used throughout the refinery in various cracking (hydrocracking) and treating (hydrotreating) units.


Uses of Crude Oil and Petrochemicals

  1. Thus the crude oil is mostly used to produce energy.
  2. Small portion of crude oil is converted into petrochemical feedstock used in production of plastics, rubber, fertilizers, cosmetics and the like.
  3. Most of the crude oil is used to obtain motor gasoline, diesel, heating oil, jet fuel, and liquefied petroleum gases.
  4. Gasoline (Used to fuel cars)
  5. Heating Oil (Used to heat buildings)
  6. Residual Fuel Oil (powering factories, fueling large ships, and making electricity)
  7. Petrochemicals are used to produce a wide variety of materials, such as plastics, explosives, fertilizers, and synthetic fibers.
  8. Food-additives are another major kinds of petrochemical which are known to act as preservatives and increase the tenure of freshness of canned food, so that the freshness of food can be enjoyed anywhere at any point of time.
  9. Sneakers (synthetic shoes) have also got petroleum products as their content.
  10. The non-stick pads made to plaster wounds are also a petrochemical product.
  11. Plastic bottles are made from petrochemicals too.
  12. Synthetic; this is a man-made petrochemical which often serves as the raw material for wrinkle-free garments. These fibers can be further finely woven tapestry, carpets, curtains, and many other things. Petrochemical is also used as fertilizers. Fertilizers like pesticides are used to protect crops from any sort of damage and increase crop production.


Importance of Crude Oil and Petrochemicals

  1. The economic importance of crude oil is that it is used to produce gasoline and other fuels used around the world.
  2. Gasoline is made from crude oil. Lubricating oil is also used to keep our automobile engines from getting too hot and to ensure that all moving parts of the machinery are kept in good working order.
  3. Increased Job Creation; Most importantly, the petrochemical industry has worked increase job opportunities across the country.
  4. Petrochemicals are used to create most of the everyday items we use. From vehicles to a variety of electronics, almost all of the things we use today are powered by or made of petrochemicals.



  1. The reforming process actually removes --------from low-octane gasoline. 
  1. hydrogen B. oxygen C. fluorine D. nitrogen
  1. In the refinery’s modernly-equipped Laboratory, chemists and technicians conduct quality assurance tests on all finished products, including checking gasoline for proper --------rating. A. octane B. nonane C. decane D. methane
  2. The reforming unit employ precious-metal catalysts – platinum and rhenium – and thereby get the name-------A.  rheniformers B. reformer C. catalizer D. none of the above
  3. --------Oil Used to heat buildings. A. Heating B. Lubricating C. Gasoline D. Residual oil
  4. ---------fiber is a man-made petrochemical which often serves as the raw material for wrinkle-free garments. A. Synthetic B. Polymeric C. Isomeric D. None of the above


  1. Mention four importance of crude oil and petrochemicals.
  2. State the steps in refining crude oil.


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