Passivation and temperature rise issues in urea synthesis towers
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In our original process, after heating the urea synthesis tower, oxygen is introduced, and then the tower is sealed for passivation. However, due to low ammonia stocks, urea production cannot proceed; therefore, after the passivation process is complete, the temperature is increased slowly (1–3°C per hour). Once it reaches 150°C, the tower is sealed again, and once the temperature drops to 100°C, heating resumes. What impact does this have on the lifespan and safety of the synthesis tower?
As long as the passivation time is sufficient, there should be no problems; after all, no medium gets in. Analyze the nickel content more thoroughly after discharging the material from the machine
There is no impact, as no corrosive substances have entered
Tip: It is advisable to perform passivation before driving. Passivation without a temperature requirement is ineffective passivation. After multiple passivations, during operation, care should be taken to prevent a rapid rise in pressure at the beginning of feeding.
It has little impact； It is recommended to keep it warm ； Don’t go up and down ； If the speed is high, it will affect the lining
Reply 1# huangniansun: Your ability to organize driving trips is really poor – you didn’t properly calculate how much ammonia would be needed for driving ? ? From starting the boiler to introducing steam into the urea production system, through gas generation and the activation of the ammonia synthesis system, as well as the normal operation of urea production, ammonia introduction, evaporation, and granulation, we have never exceeded 1 hour at any of these critical stages.
It’s not the case that the entire plant operates simultaneously; moreover, ammonia processing is not limited to urea production alone, and the operation or shutdown of the urea production unit has little impact on processes such as gas generation and boiler operations. You say that after heating to 150°C for oxygen passivation and sealing the tower for 24 hours, can the temperature inside the tower not drop?