| 摘要 |
A process for the synthesis of urea from ammonia and carbon dioxide in which high yield reaction and optimal reactor heat balance control are achieved at the same time by using two reaction zones, where two different NH3/CO2 molar ratios are maintained, and by treating the effluent from the second reaction zone in a separation treatment in two steps in series; the reactant gas stream discharged from the second treatment step is recycled, after partial condensation, to the first reaction zone, while at least part of the gas stream discharged from the first treatment step is recycled directly to the second reaction zone, the gas stream from both the first and second treatment step being so controlled as to obtain optimal NH3/CO2 ratios and optimal reaction temperatures in the two reaction zones.
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