When is the best time to stop nitrogen stripping after shutting down the low-temperature methanol washing system?

I feel that if it’s short-term parking, there’s no need to rush to reduce the amount of nitrogen used for gas stripping; of course, the exhaust gas scrubber also cannot be stopped! On the other hand, if it’s a long pause, then you can do as you please! ! Its main purpose is still to make the lean methanol meet the quality standards; it’s just a matter of how long it takes to achieve this.

For short-term shutdowns, in order to maintain the cooling capacity of the system, it is sufficient to reduce the amount of nitrogen used for stripping to the minimum; this is also done to avoid overloading the methanol regeneration tower. In the case of long-term shutdowns, it is necessary to wait until the regeneration process is complete before stopping the supply of nitrogen

I tend to agree with the view expressed above: the amount of nitrogen used for stripping determines the system’s temperature. Therefore, during short-term shutdowns, a certain amount of nitrogen should still be maintained for stripping purposes; whereas in the case of long-term shutdowns for maintenance, it is necessary to wait until the methanol production is back to normal before proceeding with the shutdown.

No need to stop for short-term parking; for longer periods, check the methanol regeneration tower first, and then stop once it is satisfactory

To preserve the system’s cooling capacity, I recommend stopping the gas supply and removing nitrogen immediately, so that it can meet the requirements sooner during the next startup. There is no need to wait for the methanol to meet the standards. Starting the machine again with unqualified methanol has little impact on the system.

For short-term shutdowns, in order to maintain the cooling capacity of the system, it is sufficient to reduce the amount of nitrogen used for stripping to the minimum; this is also done to avoid overloading the methanol regeneration tower. In the case of long-term shutdowns, it is necessary to wait until the regeneration process is complete before stopping the supply of nitrogen. There are several reasons for this: 1. It depends on what the purpose of the system shutdown is The operation for stripping nitrogen is determined; there are several different scenarios in the case of maintenance on the exhaust system. 2. It is necessary to consider the time requirements for driving the vehicle. As mentioned above, if parking is short-term, the minimum amount of nitrogen should be used for purging in order to maintain the cold temperature; in the case of long-term parking, regeneration of the system is required, and all of the CO2 must also be regenerated, otherwise it will be released naturally within the system. 3. It depends on what system it is; different process systems have different operational requirements.

If the methanol circulation continues, the nitrogen stripping process must also continue, as the circulating methanol still contains large amounts of carbon dioxide. If nitrogen stripping is stopped prematurely, a large amount of carbon dioxide will be released in the regeneration tower, causing overpressure in it and potentially triggering the safety valve to activate

Reply to 1# 654262293: As the load or gas cut-off continues in the low-temperature methanol washing process, the amount of nitrogen used for gas stripping gradually decreases. Even after all the gas has been removed, it is still necessary to supply a certain amount of nitrogen to the system, as the concentration of acidic gases dissolved in methanol remains high at this point. If nitrogen supply is stopped immediately, it can easily lead to overloading of the thermal regeneration system. Additionally, the methanol circulation will experience significant fluctuations after the nitrogen supply is stopped, which hinders the stability of the methanol circulation. During long periods of shutdown, methanol generally needs to be regenerated, which also means that nitrogen supply cannot be stopped too early.