Urea reactor effluent solution recycle in urea synthesis

Abstract From the Canadian patent

Urea synthesis process with liquid carbamate recycle, in which the reactor effluent is divided into major and minor streams. The major stream is reduced in pressure and subjected to heating and substantial carbamate decomposition to ammonia and carbon dioxide decomposer off gas either directly or after preliminary ammonia separation. The minor stream is reduced in pressure and is contacted with decomposer off gas and fresh make up carbon dioxide either directly or after preliminary ammonia separation and in indirect heat exchange with a relatively colder fluid whereupon ammonium carbamate is formed from the mixture of the minor stream, fresh make up CO2 and decomposer off gas in an aqueous …