Process for concentrating aqueous urea solutions

摘要

Disclosed is a process for concentrating aqueous urea solutions in which an aqueous urea solution is allowed to flow as a falling film in countercurrent contact with a stream of hot inert gas to concentrate it to 95-99% by weight and the aqueous urea solution so concentrated is then passed through a packed zone in cocurrent contact with a stream of hot inert gas to concentrate it to not less than 99.5% by weight.