C3- The Haber process

C3- The Haber process

1. Nitrogen and Hydrogen are needed to make Ammonia

   • The nitrogen is obtained from air (78% nitrogen) the hydrogen comes from natural gas or other sources like crude oil

2. Some of the nitrogen and hydrogen reacts to form Ammonia. Because the reaction is reversible, it occurs in both directions. Ammonia can break down into nitrogen and hydrogen. The reaction reaches an equilibrium.

3. Higher pressures favour forward reaction so the pressure is set as high as possible to give the best % yield without making it too expensive.

   • (200) atmospheres
     • The forward reaction is exothermic which means that increasing the temperature will actually move the equilibrium the wrong way, so the yield of Ammonia would be greater at lower temperatures.
       • However, lower temp means lower rate of reaction so they increase the temp anyway to get a faster reaction. (450c) compromise.

4. Ammonia is formed as a gas but as it cools in the condenser, it liquefies and id removed. The unused H and N are recycled so nothing is wasted