| 摘要 |
<p>PCT No. PCT/EP82/00188 Sec. 371 Date May 2, 1983 Sec. 102(e) Date May 2, 1983 PCT Filed Aug. 31, 1982 PCT Pub. No. WO83/00862 PCT Pub. Date Mar. 17, 1983.A process for the preparation of urea from ammonia and carbon dioxide at an elevated temperature and pressure having a reaction zone and a stripping zone. In the reaction zone, carbon dioxide and a portion of the ammonia are converted to ammonium carbamate, and a portion of the ammonium carbamate is converted to urea, the combined conversions resulting in a net formation of heat. In the stripping zone, a urea product stream containing unconverted ammonium carbamate is heated by heat exchange with the reaction zone to decompose a portion of the ammonium carbamate. In the reaction zone, the conversion of ammonium carbamate into urea is continued until the quantity of urea formed is at least 50 percent of that quantity of urea that would be obtained at equilibrium under the reaction conditions present in the reaction zone.</p> |
