Most of the world’s supply of ammonia is obtained by Haber process. It proved difficult to synthesize ammonia from nitrogen and hydrogen until L.F. Haber developed a suitable catalyst. His process enabled Germany to produce her own independent route to explosives during the World War I, for a large proportional of the ammonia is converted into nitric acid which in turn can be used to manufacture explosives.
The nitrogen cycle has been disturbed by the demand of civilization; more nitrogen compound are removed from the soil than are replaced naturally, and our of restoring the balance is to add fertilizer to the soil. These are usually compound of ammonia, which are soluble and contain nitrogen in a form which is readily available to plants.
You should know that plants cannot use atmospheric nitrogen directly, even though they are virtually surrounded by it (some plant ‘fix’ nitrogen with the help of bacteria living in their root nodules).
The Raw Materials for synthesis of Ammonia.
Nitrogen and hydrogen ate required in the ratio 1:3 by volume. Modern plants use nitrogen from the air and hydrogen obtained by processing natural gas, but the correct ratio of gases can also be obtained from a mixture of water gas and producer gas. The carbon monoxide from the mixture is made to react by being passed with excess steam over a hot catalyst consisting of oxide of chromium and iron.
The following reaction take place;
The carbon monoxide is removed by dissolving it in water under pressure, and traces of unreacted carbon monoxide are dissolved in a solution of copper (I) methanoate (formate) under pressure. This process is called Bosch process and it used to be one of the important methods of hydrogen manufacture. If it is used as part of the synthesis of ammonia the overall process is often called the Haber-Bosch Process.
The nitrogen and hydrogen gases are compressed and scrubbed to remove as many potential catalyst poison as possible before they are allowed to enter the converter.
The Collecting of Ammonia
When the gases leave the converter they are hot and under pressure. Simple cooling by water jackets is enough to liquefy some of the ammonia and it is removed in the liquid state, Ammonia is also highly soluble in water so that it is possible to remove it from the equilibrium mixture by treatment with water.