| 摘要 |
Disclosed herein is a method of utilizing inert gases, which are introduced as impurities in the feed raw materials for the synthesis of urea and also as an anti-corrosion agent into a urea process, as a stripping agent of unreacted materials in one or more of the below-mentioned separation steps, in a urea process in which: urea is synthesized from ammonia and carbon dioxide in the presence of an excess ammonia; unreacted materials including the excess ammonia are separated from the resulting urea synthesis solution as gaseous mixtures of ammonia and carbon dioxide successively at a plurality of pressure levels; the gaseous mixtures thus-separated are absorbed in solvents or condensed at the corresponding pressure levels; and the solutions or condensates thus-formed are circulated to the urea synthesis step. By this method, the separation efficiency of the unreacted materials is improved in the lower pressure separation steps, which eventually results in the improvement in the unit consumption of steam and the size reduction in some of the lower pressure equipments in the urea process.
|
