| 摘要 |
1,273,913. Synthesis of urea. MITSUI TOATSU CHEMICALS Inc. 10 June, 1970 [11 June, 1969; 10 Sept., 1969], No. 28117/70. Heading C2C. A process in which urea is synthesized comprises feeding to and reacting in a heat-recovery zone 7 maintained at urea-synthesis pressure, CO 2 and NH 3 to form a reaction mixture containing ammonium carbonate, the NH 3 /CO 2 molar feed ratio not exceeding 4 : 1, removing all of or some part of the heat of reaction from zone 7, then feeding the reaction mixture and any remaining NH 3 into a urea-synthesis zone 12 maintained at a urea-synthesis pressure to form urea, and maintaining the temperature in zone 12 substantially constant by adjusting the relative amounts of NH 3 fed to zone 7 and zone .12 e.g. through control valve 9 operated by a servomotor in response to the outlet temperature of autoclave 12. |
