Process for ammonia recovery in ammonia production

Abstract

A process and unit for the recovery of ammonia in ammonia production are disclosed. All or a portion of a high pressure liquid ammonia product stream is introduced into a syngas makeup stream to produce a mixed vapor-liquid refrigeration medium for condensing ammonia from a synthesis loop product stream. Following the product stream ammonia condensation step, the vapor component of the mixed vapor-liquid stream is compressed and cooled for condensing ammonia therefrom. Liquid ammonia separated from the low pressure mixed vapor-liquid stream can be withdrawn as a low pressure liquid ammonia product. An ammonia-lean makeup gas is then combined with the ammonia-containing product recycle gas stream from the synthesis loop and further compressed. The process preferably includes recycle of all or a portion of the low pressure liquid ammonia product as a supplemental refrigerant. A high pressure, ammonia-lean syngas vapor stream obtained following separation of the high pressure ammonia condensate can be used as a process cooling medium for chilling the syngas makeup stream and syngas stream. In such a manner, both ammonia and syngas compression can be consolidated in a single syngas compressor and the use of an ammonia refrigeration compressor can be eliminated.

Dependencies are inferred from the claim text.