Harbor and Contact process

• Ammonia


  A very important chemical, needed to make fertilisers
• Haber process


  Nitrogen and hydrogen react to produce ammonia
• Haber process


  • Reactants are nitrogen and hydrogen
  • Nitrogen obtained from air by fractional distillation or reacting oxygen with hydrogen
  • Hydrogen obtained by reacting natural gas (methane) with steam or catalytic cracking of hydrocarbons
• Haber process


  1. Reactant mixture compressed at 200atm and 450°C with iron catalyst

  2. Ammonia condensed and removed, nitrogen and hydrogen recycled
• Haber process is a reversible reaction


  Forward reaction is exothermic, backward reaction is endothermic
• Haber process


  • Yield of ammonia is only 15% and needs to be improved
• Ways to improve ammonia yield in Haber process

  1. Reduce temperature

  2. Increase pressure

  3. Remove ammonia from equilibrium

  4. Use a catalyst
• Haber process conditions
• Haber process yield is 98% ammonia
• Sulfuric acid


  A major product of the chemical industry, made from sulfur dioxide in the contact process
• Contact process


  Sulfur dioxide and oxygen react to form sulfur trioxide
• Contact process reaction


  Forward reaction is exothermic, backward reaction is endothermic
• Raw materials for contact process

  • Sulfur, air, water or sulfur dioxide, air, water
• Contact process


  1. Compromise temperature of 450°C used

  2. Vanadium(V) oxide catalyst used

  3. Pressure of 200kPa used