| 摘要 |
A urea production process in which the urea solution produced in the reaction zone is treated in sequence with a first thermal decomposer at the same pressure as the reaction, to decompose part of the residual ammonium carbamate into its components, then with an adiabatic stripper in which the free ammonia is stripped with CO2 operating at a pressure which is 1-7 MPa less than the synthesis pressure, then with two further carbamate thermal decomposition stages at decreasing pressures. The gaseous products obtained from those stages at pressures less than the synthesis pressure are mixed with the recycle solutions from the downstream stages, condensed by heat transfer against said downstream stages, and then recycled to the reaction as liquid. <IMAGE> |
