Low-temperature methanol washing gas introduction and shutdown
Thread Content
When starting up or shutting down the low-temperature methanol wash unit, those level control valves should be set to manual mode in order to maintain stability of the system’s liquid level and prevent issues such as cross-contamination of gases
Generally, the valves that convert high pressure to medium pressure and medium pressure to low pressure are operated manually; automatic mode is activated only after the system stabilizes
During gas guiding, automatic mode is generally used, while the liquid level at the bottom of the two towers is controlled manually to maintain a stable liquid level in the methanol-poor tank； After power is cut off, switch the pressure differential-controlled level control valve to manual mode; it can be closed after stopping the methanol circulation
When starting up or shutting down the low-temperature methanol wash unit, I believe it is better not to switch from automatic to manual mode; instead, adjustments should be made based on the actual situation. First, the introduction of gas is done very slowly, rather than introducing the process gas all at once; since it is introduced slowly, one should wait until the system is stable before introducing the gas. If there is a sudden power outage, it is even less appropriate to switch to manual mode, as the system becomes chaotic in such situations. With insufficient staff to handle things manually, it’s possible that proper attention won’t be given, leading to high voltage leaking into the low voltage circuit. It is only in cases where automatic adjustment is insufficient that manual assistance adjustment is used.
During system gas introduction and gas cut-off. The things to pay attention to are also different. Could you make it clearer?
The gas guidance is a very slow process, and no manual intervention is required. The power loss happens in an instant; in some high-pressure areas, it should be quickly switched to manual mode
I believe that all control valves for regulating pressure from high to low, including those used for gas guidance and shutdown, should be in manual mode to facilitate operation, thereby preventing cross-flow of gas from high pressure to low pressure or the occurrence of high liquid levels that could affect normal operation.