Regarding steam pressure control
Thread Content
In the CO2 stripping process, there is a guideline regarding operation: when shutting down the system, the pressure in the high-pressure steam vessel should be maintained at 10 bar, while that in the low-pressure steam vessel should be kept at 6 bar. What is the purpose of maintaining the pressure in the high-pressure steam vessel at 10 bar?
The high-pressure drum is kept below 1.0 MPa mainly because the gas column has not yet started stripping, and excessive pressure could damage the equipment. Keeping the low-pressure limit at 6 bar prevents the raw material from condensing inside the condenser
Prevent overheating of the columns in the air lift tower, which could lead to increased corrosion. It is reduced to 1.0 Mpa from the perspective of protecting the equipment.
The situation described by the poster is required when a urea plant using the CO2 stripping process undergoes a short-term shutdown, and it is necessary to maintain heat and pressure in the high-pressure section. The main purpose of maintaining the pressure in the high-pressure steam drum at 10 bar is to insulate the stripping tower, prevent excessive condensation within it, and stop the urea synthesis solution in the urea tower from flowing back into the stripping tower
I agree with you quite a bit~~ If the synthesis liquid is poured into the stripping tower, could this cause uneven distribution of CO2 within the tubes during operation?
Due to the emergency shutdown, CO2 is stopped immediately and the liquid output from the synthesis tower is shut off; as a result, there is less oxygen in the high-pressure system while there is more liquid in 201-C. Therefore, it is necessary for the steam pressure to be low enough so that the gas does not condense, thereby reducing corrosion in 201-C. The controlled pressure is 0.55 MPa, corresponding to a temperature of 163°C, which is slightly higher than the gas condensation temperature at this pressure. After the tower is sealed for normal shutdown, if a 201-D \"liquid backflow\" occurs, the steam pressure must also be reduced to 0.55 MPa. This post was last edited by lxq700918 on 2009-2-5 17:19.]