Petroleum & Cracking: Fractional Distillation, Octane Number, and Reforming

Fractional Distillation

Fractional distillation is a process used to separate a mixture into its component parts, or fractions, based on differences in boiling points. It is commonly used in the petroleum industry to refine crude oil into useful products.

• Crude Oil: A complex mixture of hydrocarbons.
• Fractionating Column: A tall tower where the separation occurs.
• Boiling Points: Different components boil at different temperatures, allowing separation.

How Fractional Distillation Works

1. Heating: Crude oil is heated until it vaporizes.
2. Rising Vapors: Vapors rise through the fractionating column.
3. Condensation: As vapors cool, they condense at different levels based on boiling points.
4. Collection: Fractions are collected at various heights.

 

Octane Number

The octane number is a measure of a fuel's ability to resist knocking during combustion in an engine. Higher octane numbers indicate better resistance to knocking.

• Knocking: Uncontrolled combustion causing engine noise and damage.
• High Octane Fuels: Provide smoother engine performance.
• Measurement: Compared to a mixture of iso-octane (100) and heptane (0).

 

Reforming

Reforming is a chemical process used to improve the quality of gasoline by increasing its octane number. It involves rearranging or breaking down hydrocarbon molecules.

• Catalytic Reforming: Uses catalysts to alter molecular structures.
• Improved Fuel Quality: Results in higher octane gasoline.
• Hydrogen Production: A byproduct of the reforming process.