UREA PRODUCTION PROCESS CHARACTERIZED BY SHORT UREA MELT TRANSPORTATION TIME BETWEEN LAST CONCENTRATOR AND PRILLING TOWER

摘要

The invention relates to a method for urea production and to a urea production plant wherein ammonia emission in the final step of forming urea prills is reduced. In the method the concentration of a urea solution is performed in at least three consecutive concentration steps and the residence time of urea melt leaving a last concentrator to the prilling tower is minimised. This can be achieved by placing the last concentrator in adjacency with a urea melt inlet of the prilling tower such as above the prilling tower. In this way the ammonia emission in the prilling tower can be reduced by as much as 50% compared to the conventional urea production plants. The invention further relates to a method for reducing ammonia emission in the prilling tower of an existing urea production plant.