Patent ID: 8129565

Claim:
A process for producing urea, where ammonia and carbon dioxide are reacted in a high-pressure loop comprising at least a synthesis reactor, a thermal stripping section and a carbamate condensation section, the process comprising the steps of: subjecting a urea solution produced by reacting the ammonia and carbon dioxide to an adiabatic stripping process in an adiabatic stripping section, with a carbon dioxide feed as a stripping medium, obtaining a liquid urea solution and a vapour phase containing ammonia and carbon dioxide, further subjecting the urea solution obtained in said adiabatic stripping process to thermal stripping in said thermal stripping section, and recycling said vapour phase to the reaction zone of said synthesis reactor, said thermal stripping section including a self-stripping unit with no addition of any stripping medium or a CO 2 -stripping unit in which carbon dioxide is fed for use as a stripping medium, and a carbon dioxide feed is split into: a first portion sent to the adiabatic stripping section; a second portion sent to the reactor and a third portion sent to the thermal stripping section, said first portion of the carbon dioxide feed being 20 to 60% of the total feed.