| 摘要 |
In a process for the synthesis of urea from NH3 and CO2 in two reaction zones with different NH3/CO2 ratios, the product from the second zone is treated in two separation stages in series. The gases discharged in the second treatment stage are recycled, after partial condensation, to the first reaction zone, while at least a part of the gases discharged in the first treatment stage is recycled to the second reaction zone. The flows from the first and second treatment stages are controlled in order to obtain the optimum NH3/CO2 ratios and reaction temperatures in the two reaction zones.
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