Saipem Limited

Paolo Casara

Alessandro Gianazza

Ivano Miracca

Gustavo Capannelli

Giuseppe Merelli

Aldo Bottino

The present invention relates to a method for contemporaneously recovering ammonia and carbon dioxide from an aqueous solution thereof, possibly comprising their condensates, in a synthesis process of urea, characterized in that it comprises a hydrophobic microporous membrane distillation phase of an aqueous solution comprising ammonia, carbon dioxide and their saline compounds or condensates, said distillation being carried out at a temperature ranging from 50 to 250&#xb0; C. and a pressure ranging from 50 KPa to 20 MPa absolute, with the formation of a residual aqueous solution, possibly comprising urea, and a gaseous permeate stream, comprising ammonia, carbon dioxide and water. The present invention also relates to an apparatus for effecting the above method and a production process of urea which comprises the above method.

Method for the separation of ammonia and carbon dioxide from aqueous solutions

The present invention relates to a process for the recovery of ammonia contained in a gaseous stream, said process comprising the following phases: (a) subjecting the gaseous stream containing ammonia to a washing with an aqueous washing solution having a pH lower than 7.0, with the formation of a purified gaseous stream and an aqueous solution containing an ammonium salt; (b) treating the aqueous solution containing the ammonium salt coming from phase (a) in a vertical falling film heat exchanger at a temperature from 50 to 250&#xb0; C. and an absolute pressure ranging from 50 KPa to 4 MPa with the formation of a regenerated washing solution and a gaseous stream comprising NHand HO; (c) recycling said regenerated washing solution to phase (a). The present invention also relates to equipment for effecting the above process.

Process and apparatus for recovering ammonia from a gas stream

A process for the recovery of ammonia contained in a gaseous stream is described, said process comprising the following phases: (a) subjecting the gaseous stream containing ammonia to a washing (S) with an aqueous washing solution () having a pH lower than 7.0, with the formation of a 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 a distillation process (MD) with a hydrophobic microporous membrane at a temperature ranging from 50 to 250&#xb0; C. and a pressure ranging from 50 KPa to 4 MPa absolute with the formation of a regenerated washing solution () and a gaseous stream () comprising NHand HO; (c) recycling said generated washing solution to phase (a). The equipment for carrying out the above process is also described.

Process for the recovery of ammonia from a gaseous stream

A process for the recovery of ammonia contained in a gaseous purging stream produced in a synthesis process of urea.

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San Donato Milanese, Italy

Paolo Casara