| 摘要 |
<p>In the prepn. of urea, a carbamate and free ammonia contg. urea synthesis soln. is formed from CO2 and excess NH3 in a synthesis zone at 125-350 bar. A portion of the carbamate in the urea synthesis soln. is decomposed in a stripping zone at the pressure of the synthesis zone or at a low pressure by heat supply and countercurrent contact with a stripping gas. The carbamate decomposition prods. together with a portion of the excess ammonia and stripping gas are removed from the stripping zone as a gas mixt. A portion of the gas mixt. obtd. is condensed in a zone and the stripped urea synthesis soln. is processed into a urea soln. or solid urea.</p> |
