Compressor circuit control
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How is the cycle line of the compressor controlled? Is that signal prioritized? Is it the pressure signal before the compressor, or the pressure signal after the compressor? When the pressure before the compressor is high, how does the control valve on the circulation line operate?
I’m not sure about your process; the pressure at the front end is low, while the pressure at the back end is high. A normal compressor has low-pressure protection and high-pressure protection. Both are equally important for ensuring the proper operation of the compressor.
Isn’t the control system a bit too complicated? With two detection points and three control valves, will they not interfere with each other? For example, if the inlet pressure is low, should both related valves be opened, or just one? Does the inlet control valve seem a bit unnecessary? On the circulation line, it is used to prevent compressor surge; logically, it should be controlled based on low pressure. Since the outlet is already vented, there should be no valves that allow fluid to flow back into the circulation line. It seems like the control system is complicated and chaotic
The control valve at the compressor inlet is fully open; under normal operation this valve remains unchanged. The return line serves as a anti-surge line, designed to prevent surging in the compressor. The outlet pressure relief valve is activated only in emergency situations such as when there is no path for flow elsewhere. Generally, the compressor regulates its outlet pressure by adjusting its speed – it is sufficient to ensure that the compressor operates properly. If the inlet pressure is high, it is enough to adjust the compressor’s speed to maintain normal outlet pressure; at such times, the anti-surge valve will close slightly~
Judging from the process, it should be a reciprocating compressor. It mainly depends on which point’s pressure needs to be controlled in the process: the inlet or the outlet? Once determined, the control scheme is basically clear.