Problems with normal shutdown of low-temperature methanol washing in the Linde process
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What issues should be considered during a normal shutdown of the low-temperature methanol washing process in the Lind process?
The methanol solution can be discharged only at room temperature; the steam load on the heat regeneration tower can be reduced only after all of the H2S and CO2 in the methanol-rich solution have been flashed off. Methanol drain liquid must not be discharged indiscriminately
Turn off the process gas first when parking the vehicle~! Maintain pressure to sustain the methanol cycle until methanol regeneration is complete, then send it to the methanol-water separation tower~! For the refrigeration system, it is advisable to store methanol in the bottoms of each tower to facilitate operation during the next start-up~
After cutting off the gas while parking. . Pay attention to the liquid levels in each tower and stop the pump once. . Be sure to stop pump P3 first before stopping pump P4. . Prevent low-temperature methanol from entering high-temperature or normal-temperature systems
It depends on the length of time the system is parked; if the parking time is long, the circulation can be stopped after methanol regeneration, and then the pressures in the high- and low-pressure sections of the system should be reduced to prevent cross-connection of gases between these pressure levels； At the same time, care must be taken to ensure that the liquid level at the bottom of the stripping tower is not too high, in order to prevent nitrogen from entering the pipeline. Also, if direct steam is supplied to the methanol-water separation tower, be sure to remember to turn it off, etc