A process for the recovery of waste gases from urea synthsis disorders - product flow

摘要

1,134,849. Synthesis of urea. CHEMICAL CONSTRUCTION CORP. 12 Jan., 1967 [20 Jan., 1966], No. 1791/67. Heading C2C. A urea synthesis process comprises recovering ammonia and carbon dioxide from the product stream by reducing the pressure adiabatically and removing an initial off-gas, heating the product stream to generate a first off-gas, absorbing at least some of the first off-gas in an aqueous medium, lowering the pressure of the residual product stream and passing the product stream in heat exchange with the absorption product of the first off-gas to heat the product stream and generate a second offgas. The process is suitably operated continuously and the initial off-gas may be combined with the mixture of first off-gas and absorbing medium (suitably an ammonium carbonate solution) discharged from the heat-exchange for recycle to urea synthesis. The pressure of the product stream after removal of the first off-gas may be reduced adiabatically, a partial off-gas separated prior to heating to form the second off-gas and said partial off-gas combined with the second off-gas. An apparatus suitable for carrying out the reaction continuously is described.