Chemistry Lesson Note On Petroleum and Petrochemicals – Refining, Fractional Distillation

Topic: Petroleum and Petrochemicals – Refining, Fractional Distillation

Class: SS1

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Specific Objectives:

By the end of this lesson, students should be able to:

1. Define petroleum and petrochemicals.
2. Explain how petroleum is formed.
3. Describe the refining process of crude oil.
4. Explain the process of fractional distillation.
5. Identify the major fractions of crude oil and their uses.

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Instructional Materials:

• Chart showing the fractional distillation column
• Samples of petroleum products (or labeled pictures)
• Short video/animation on refining of crude oil (if available)
• Whiteboard and marker

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Lesson Content:

Step 1: Definition and Formation of Petroleum

• Petroleum is a naturally occurring, flammable liquid found in rock formations beneath the Earth’s surface. It consists mainly of a mixture of hydrocarbons.

• Petrochemicals are chemical products derived from petroleum and natural gas, used to produce plastics, detergents, fertilizers, etc.

Formation:

• Formed millions of years ago from the remains of marine organisms buried under sedimentary rock.
• Through heat, pressure, and time, the remains were transformed into crude oil and natural gas.

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Step 2: Refining of Crude Oil

• Crude oil must be refined before use.
• Refining is the industrial process used to separate crude oil into its useful components.

There are two major refining processes:

1. Physical Separation (Fractional Distillation)
2. Chemical Conversion (Cracking, Reforming, etc.)

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Step 3: Fractional Distillation of Petroleum

• Fractional Distillation is the process of separating a mixture into its component parts or fractions, based on differences in boiling points.

How it works:

• Crude oil is heated to about 400°C and fed into a fractionating column.
• The column is hot at the bottom and cooler at the top.
• Different hydrocarbons condense at different levels depending on their boiling points.

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Step 4: Main Fractions of Petroleum and Their Uses

Fraction	Boiling Point Range	Uses
Petroleum gases	< 30°C	LPG (cooking gas)
Gasoline (petrol)	30 – 200°C	Fuel for cars
Naphtha	100 – 200°C	Petrochemical feedstock
Kerosene	150 – 275°C	Jet fuel, cooking fuel
Diesel oil	200 – 350°C	Fuel for trucks and buses
Lubricating oil	> 300°C	Lubricants for machines
Fuel oil	> 350°C	Power stations, ships
Bitumen	Residue	Road surfacing, roofing

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Evaluation:

1. What is petroleum and how is it formed?
2. Define petrochemicals and give two examples.
3. What is refining of crude oil?
4. Describe the process of fractional distillation.
5. List any four fractions of petroleum and state one use of each.

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Homework:

1. Draw and label a simple diagram of the fractional distillation column.
2. Explain why gasoline condenses at the top of the fractionating column while bitumen is collected at the bottom.
3. State two differences between physical refining and chemical refining of crude oil.

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Conclusion:

Petroleum is a valuable natural resource from which many important fuels and chemicals are derived. Through fractional distillation, crude oil is separated into useful components, each with specific applications in daily life and industry.

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