| abstract |
Process for the preparation of urea in which n- in a reaction zone a carbamate and free ammonia containing urea synthesis solution is formed from carbon dioxide and an excess of ammonia, n- in a stripping zone at least part of the carbamate that is present is decomposed with carbon dioxide as stripping gas, n- the carbamate decomposition products together with part of the excess of ammonia and the stripping gas are removed from the stripping zone as gas mixture, n- part of the gas mixture obtained is supplied to a condensation zone, in which it condenses, after which n- the carbamate containing mixture is supplied to the reaction zone and the stripped urea synthesis solution is processed into a urea solution or solid urea. n The carbamate containing solution is caused by gravity to flow out of the condensation zone to the reaction zone and from the reaction zone to stripping zone, placed at the same or virtually the same height, and the heat required for the formation of urea in the reaction zone is generated through condensation of at least part of the remainder of the gas mixture discharged from the stripping zone. |