Problems with PSA programmable control valves for hydrogen production in the refining industry
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Yesterday I encountered a problem with a programmable valve. The downstream side of the valve is connected to the process output pipeline, where there is a pressure of 20 kilograms. The upstream side of the valve is connected to one of the PSA towers. It’s a valve with a piston, and the two outputs of the solenoid valve are connected to the upper and lower sides of the cylinder respectively. I have a question for everyone: if I stop the air supply, will the valve be open or closed? And why?
The cylinder is connected to the air supply at both the top and bottom; there is a pressure of 20 kilograms downstream. Therefore, the pressure upstream of the valve must be at least around 20 kilograms as well. After turning off the gas supply, whether the valve is open or closed depends on its installation direction and the changes in pressure difference upstream and downstream. If the pressure difference remains stable, the valve will close when fluid enters from the high side and exits from the low side, and it will be pushed open when fluid enters from the low side and exits from the high side. If the pressure difference changes significantly over time, the valve may sometimes open and sometimes close.
Based on the poster’s description, the programmable valve should be a double-acting actuator. When the power is cut, the valve should remain in its original position.
Theoretically, it should remain in its position during a failure, but due to the pressure inside the pipe, it will be pushed away. It’s best to find a way to install a limit mechanism before carrying out the maintenance.
If you simply cut off the air supply. Instead of remotely shutting off the gas supply. The valve pit must remain in its original position; regardless of whether the air supply valve is open or closed, ventilation is necessary. The air pressure in the cylinder cannot be released; the valve functions as it does during normal operation. The pressure inside the pipeline has little impact. Stay in place
If you simply cut off the air supply. Instead of remotely shutting off the gas supply. The valve pit must remain in its original position; regardless of whether the air supply valve is open or closed, ventilation is necessary. The air pressure in the cylinder cannot be released; the valve functions as it does during normal operation. The pressure inside the pipeline has little impact. Stay in place
The valve was opened; there was no air supply, but the pipeline had pressure, which pushed the valve open. Test results
I mainly want to ask whether, after the air supply is stopped, the pressure in the pipeline will cause the valve to open or close
Why is this the case? What’s the scale of it? The principle of wind line pressure – why is the pressure in the pipeline so low?
Why is it pushed away, and what is its relationship to the flow direction?
It depends on the design of your valve body/valve core to determine whether it can withstand the pressure difference between the front and back. . .