Process for the preparation of urea

摘要

There is described a process for the preparation of urea which is utilisable in the conversion of a urea synthesis process with recycling of solution of the non-stripping type to a urea synthesis process with recycling of solution of the stripping type. In this process an absorption solution which has been obtained by separation of the unreacted ammonia and carbon dioxide which are left in the urea synthesis liquor from the stripping process step as a mixed gas, and absorbing of the mixed gas in an absorption medium, is subjected to a urea synthesis together with one part in each case of prepared ammonia and carbon dioxide in order to obtain a urea synthesis liquor, and a mixed gas comprising unreacted ammonia and carbon dioxide from the stripping process step is condensed in the urea synthesis liquor.