METHOD OF CARBAMIDE SYNTHESIS Russian patent published in 1995 - IPC

FIELD: chemical technology. SUBSTANCE: synthesis of carbamide is carried out by interaction of carbon dioxide with 2.8-4.2 M ammonium excess at 183-190 C under pressure 14-19 MPa in two zone synthesis. Ammonium and carbon dioxide were added to the first zone in the mixture with recirculating carboammonium salts solution, and fresh ammonium and carbon dioxide were added to the second zone and gaseous phase from the first zone or gases mixture from the second zone were fed to the first zone and then synthesized gaseous products were fed to the absorption stage by carboammonium salts solution. Liquid smelt is decomposed in steaming zone at heat supply and carbon dioxide under pressure that equal that in synthesis zone. Steamed carbamide solution is treated successively at distillation stages under low pressure and water evaporation under vacuum, and concentrated carbamide and carboammonium salts aqueous solution were obtained. The latter is recirculated in system as an absorbent. Synthesized carbamide is used as a component of fertilizer. EFFECT: increased conversion of carbon dioxide, decreased energy consumption. 3 dwg