Improvements in or relating to separation process of ammonia from synthesized urea liquid

摘要

In the synthesis of urea from ammonia and carbon dioxide wherein the aqueous product is heated to drive off water, ammonia and carbon dioxide and the resulting vapours are passed successively through a stripping zone and an enrichment zone of a distilling column, water is added to the enrichment zone and the ammonia so produced is recycled. The added water, which may contain dissolved ammonia, prevents blockage of the column due to accumulation of ammonium carbamate. The amount of water added is 100-600 (preferably 300-400) lb. per ton of urea.ALSO:In the synthesis of urea from ammonia and carbon dioxide wherein the aqueous product is heated to drive off water, ammonia and carbon dioxide and the resulting vapours are passed successively through a stripping zone and an enrichment zone of a distilling column, water is added to the enrichment zone and the ammonia so produced is recycled. The added water, which may contain dissolved ammonia, prevents blockage of the column due to accumulation of ammonium carbonate. The amount of water added is 100-600 (preferably 300-400) lb. per ton of urea.