Cooling of the urea synthesis tower
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It’s that time again for the annual major maintenance. Cooling the urea synthesis tower using the aqueous solution full-circulation method is a real challenge. I would like to ask all experts here to share their insights: after the system is shut down and the urea synthesis tower is purged with steam, how long does it take for the atmosphere to fill the tower before its cover can be removed? When should the lower three check valves be removed? Use air or water for cooling?
After steam purging of the urea synthesis tower, it can have its top cover lifted after about 2 hours, and after introducing plant air for around 8 hours； Forcible cooling with water is strictly prohibited
After steam displacement, the air cools down too slowly in the urea synthesis tower； Cooling can be controlled by the ammonia preheater using water via a high-pressure liquid ammonia pump, according to the cooling rate (the reverse of the heating process). It works well and is safe.
Develop a plan and strictly follow it! ! ! Water cooling is effective; that’s how we do it.
4# yyg2507 I wonder what temperature of water you use for cooling? During the cooling process of the recombination tower, strict requirements are in place; generally, natural cooling is used, and water cooling is strictly prohibited.
Approximately 2 hours after steam displacement in the urea synthesis tower, the lower three check valves were removed; once the upper cover was lifted off； Use a blower for forced ventilation; once the temperature in the tower drops to around 100 degrees, add steam condensate at around 80 degrees from the top of the tower to lower the temperature.