| 摘要 |
1,246,660. Improvements in the production of urea. STAMICARBON N.V. 18 Dec., 1968 [21 Dec., 1967], No. 60248/68. Heading C2C A process for the preparation of urea, in which ammonia produced from nitrogen and hydrogen in an ammonia synthesis reactor is passed to a urea-synthesis reactor and therein reacted with CO 2 to form urea, is characterized in that an NH 3 -, H 2 - and N 2 -containing gas stream derived from the said ammoniasynthesis reactor is passed under elevated pressure into an absorbing zone and therein passed in countercurrent flow to an absorbing agent for ammonia consisting of water or an aqueous solution of urea or an aqueous solution of ammonia and carbon dioxide whereby ammonia is removed from the said gas stream in the form of an ammonia solution and the said ammonia solution is passed to the urea synthesis reactor. The aqueous solution of urea, or of ammonia and carbon dioxide, may normally be obtained from a urea plant. The process may be operated continuously, suitable forms of apparatus being described. |
