How to handle faults in the switch valves of air separation purifiers
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Air separation purifier, one unit is in operation while the other is being regenerated. With so many inlet valves, outlet valves, pressure equalization valves, vent valves, and regeneration inlet and outlet valves, what should be done if a valve fails to open when it should or fail to close when it should? Have the experts encountered this before? How is it all resolved: handshake. As a supplementary note, the control valve I’m referring to might also be called a programmable valve; although the terms vary, they mean the same thing.
This is a very common situation: the valve cannot be opened or it does not open fully. The logic of molecular sieves doesn’t always proceed in a downward direction; by pausing the molecular sieve and adjusting the valves, things can be fixed. Handle the valve properly and adjust it to the correct position. The logic continues downward.
If it is a problem with the actuator and the valve has a manual/auto switch, it can be switched to manual mode to open or close it; the program will then be executed. If the process still does not proceed as expected, after confirming that the valve operates properly and after the set time has passed, it is possible to skip steps in the program and select an appropriate time to deal with the valve. If it is a fault with the limit switch but the valve’s position is normal and there is enough time, the limit switch can be repaired while the system is still in operation. If time is insufficient, it is possible to skip those steps first and repair the limit switch at a later time~~
In fact, this issue arises over time as the system runs; the principle for dealing with it is to \"not affect subsequent systems,\" unless it’s necessary to shut down the system to address it. When encountering blockages or failures, don’t panic; first think through the appropriate measures. Do not open or close the air valves at the inlet and outlet of the molecular sieve hastily, as this can have a significant impact. When handling the dirty nitrogen gas valve, it is necessary to check whether the process is in the heating stage to avoid damaging the electric heater.
For response issues, switch to bypass; for valve issues, switch to manual mode. Then find someone to fix the instrument.
Accidents are quite common with molecular sieves, but if not handled carefully, they can easily lead to the shutdown of the entire air separation unit; careful attention is required when such problems occur. First, find out what the problem is, and then deal with it. Double-check after the processing is complete. Confirm completion for Go to Bypass, Continue, Skip, etc.
Handle it according to the specific issue: if the valve does not open fully and there is no feedback, a torque wrench can be used to assist. If there is no feedback after the valve is closed, the corresponding solenoid valve for exhaust can be adjusted on site.
Is it about switching and regenerating the two adsorption towers? They are all under program control via solenoid valves, so it’s generally not possible for there to be inadequate control or failure to respond to signals. Nowadays, such regeneration towers are equipped with modular control systems, so there’s no need to worry about failures in operation. The material of the valve should indeed be considered. In areas with poor air quality and acidic conditions, compression together with water can cause corrosion. We have previously encountered corrosion in the inlet three-way solenoid valve, which resulted in ineffective regeneration and dehydration, with a consistently high air dew point.
Take a look at my previous post: Everyone, come and see how to choose this three-way valve ? http://bbs.hcbbs.com/thread-1203392-1-1.html (Source: Haichuan Chemical Industry Forum)