Patent ID: 8293201
Filing Date: 2012-10-23
Classification: B01D,C02F,C07C,Y02P

Abstract:
1. A process for the recovery of ammonia contained in a gaseous purging stream produced in a synthesis process of urea, said process comprising the following phases: a) subjecting the gaseous purging stream to a washing with an aqueous acid solution, at a pH ranging from 1 to 6, with the formation of a first purified gaseous stream and an aqueous solution containing an ammonium salt; b) subjecting the aqueous solution containing the ammonium salt coming from phase a) to stripping, after treatment with a strong base, at a temperature ranging from 50 to 250° C. and a pressure ranging from 1 to 40 absolute bar, with the formation of a second gaseous stream comprising NH c) subjecting the solution containing the salt of the cation of the strong base coming from phase b) to a Membrane Electrochemical Process (MEP) with the formation of an aqueous solution of the acid used in phase a), an aqueous solution of the base used in phase b) and possibly a diluted aqueous solution of the cation salt of the strong base; d) recycling said aqueous solution of the acid and aqueous solution of the base to phase a) and to phase b) respectively, and recycling said second gaseous stream coming from phase b) to the urea synthesis process.