Fertilizers

The primary industrial method for ammonia synthesis is the Haber-Bosch process, created by Fritz Haber in 1905 and developed for industry by Carl Bosch in 1910. The overall process synthesizes ammonia from molecular Nitrogen (N2) and Hydrogen (H2) by feeding the reactants over iron catalysts at a high pressure and temperature. The H2 is first produced by one of the syngas production processes described previously, and then separated into a pure H2 stream. The N2 and H2 are reacted in a ratio of 1:3 in the following reaction:

N₂ + 3H₂ → 2NH₃

The ammonia product is recovered in a liquid or gaseous form, depending on whether it will be sold as is or converted further to other products.

For urea production, the ammonia is then reacted with CO₂ (which could be provided from the AGR system) in the following two-step reactions at high temperature and pressure:

2NH₃ + CO₂ ↔ NH₂COONH₄ (ammonium carbamate)

NH₂COONH₄ ↔ H₂O + NH₂CONH₂ (urea)

The urea contains a mixture of unreacted NH₃ and CO₂. As the pressure is reduced and heat is applied, the ammonium carbamate decomposes to NH₃ and CO₂, which are recycled to produce more ammonium carbamate. The urea solution is concentrated and then granulated for use as fertilizer.