Chiller: anti-surge valve won’t shut off, reduce speed?
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We have propylene compressors; during design, the amount of propylene gas coming from the low-pressure separator was set at 29,000. However, now the amount of propylene produced by flash evaporation in the low-pressure separator is not that much, which forces us to use anti-surge make-up air. I was wondering whether reducing the speed of the compressor could enable us to turn off the anti-surge system. Are there any users who have encountered a similar situation?
When the intake volume is insufficient, adjusting the speed can reduce the opening degree of the anti-surge valve, but it cannot be used as the primary method of adjustment. It can assist in regulation, but regulation mainly relies on the anti-surge valve. Since the speed adjustment range is not very large, it can be adjusted appropriately, but without affecting the process system.
Yes, the compressor adjustment methods include reducing the speed, but it is necessary to prevent the speed from dropping to the shutdown speed.
Find the performance curve of the compressor and see in which area of that curve your operating conditions fall; in this case, speed regulation offers a better cost-performance ratio compared to bypass regulation
Based on the compressor’s performance curve, identify the optimal operating point. Also, having surge at a certain opening degree doesn’t necessarily mean there is a problem; speed and the anti-surge valve are merely methods for regulating the compressor, while the root cause lies in the amount of vapor that flashes. Controlling the process to increase the intake volume is what’s truly important.
It’s just that the compressor I bought is too large. There was a problem with the design. I now want to optimize it in order to reduce steam consumption
I don’t know what requirements your system has regarding the compressor outlet – pressure or flow rate. Normally, the speed of the compressor can be reduced to adjust these parameters
Propylene compressor, used in conjunction with low-temperature methanol washing
It is adjusted by reducing the speed; after the speed is lowered, the operating point inevitably moves away from the anti-stall line, and at this point the anti-stall valve is gradually closed as appropriate