Method and apparatus for manufacturing ammonia synthesis gas from a stream of gas rich in hydrogen and a stream of nitrogen.

摘要

A stream of gas rich in hydrogen is cooled and is washed with nitrogen in a nitrogen wash column (104) to remove impurities. Gaseous hydrogen and nitrogen leave the top of the nitrogen wash column (104) and the appropriate amount of nitrogen is added to form ammonia synthesis gas. The gaseous nitrogen and hydrogen leaving the top of the nitrogen wash column is warmed (202, 204) before the addition of nitrogen so that the resulting mixture is in the vapour phase thereby avoiding the difficulties associated with the prior art where the addition of nitrogen was carried out immediately downstream of the nitrogen wash column and two phases were produced due to the cooling effect produced by the addition of the nitrogen.