Ammonia recovering from ammonia synthesis

摘要

Ammonia synthesis gas is treated to recover ammonia by (a) absorbing the ammonia contained in the effluent from the synthesis reactor by means of an absorption film to obtain a concentrated ammonia soln. (b) condensing the water in the recycle gas and in the fresh gas feed by heat exchange with dried gas, to give a dil. ammonia soln. (c) injecting ammonical liquid in the total gaseous stream to dehydrate the gas by adiabatic evaporation, and (d) passing this gas to the heat exchanger after passage through a separator, from which a concentrated ammonia soln. is withdrawn. Very concentrated ammonia solns. can be obtained economically from the ammonia synthesis gas. The concentrated ammonia soln, can be used for absorbing the CO2 contained in the crude gas utilised for the ammonia synthesis. The ammonium carbamate formed can the used in urea synthesis.