Notes: Fractional Distillation of Crude Oil

Introduction

• Subject: Fractional distillation of crude oil
• Purpose: Describe separation of hydrocarbons via fractional distillation and state functions of important fractions.

Crude Oil and Hydrocarbons

• Crude oil: Mixture of hydrocarbons
• Hydrocarbons: Each has different boiling points
  • Longer chains = Higher boiling points

Fractional Distillation Process

• Purpose: To separate hydrocarbons in crude oil into useful fractions
• Setup: Large fractional distillation columns
  • Columns are hotter at the bottom, cooler at the top

Stages of Fractional Distillation

1. Heating:
   • Crude oil is heated to high temperature
   • Causes crude oil to boil, turning hydrocarbons into vapor
2. Feeding into Column:
   • Vapor fed into the fractional distillation column
   • Hydrocarbons rise up the column
3. Condensation:
   • Hydrocarbons condense at their boiling points, turning back to liquid
   • Liquid fractions are removed
4. Collection:
   • Very long chain hydrocarbons have high boiling points and are removed from the bottom
   • Very short chain hydrocarbons have low boiling points and are removed from the top as gases

Functions of Fractions

• Fuels:

  • Petrol and Diesel: Fuel cars
  • Kerosene: Jet fuel
  • Heavy fuel oil: Power ships
  • Liquefied petroleum gas: Camping stoves

• Feedstock for Petrochemical Industry:

  • Used to make solvents, lubricants, detergents, and polymers

Exam Preparation

• Fractional distillation frequently appears in exam questions
• Further resources: Revision workbook available from the instructor's site

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Remember to review the stages of fractional distillation as they are important for exams.