How is the compression ratio allocated among the various stages of a multi-stage reciprocating compressor?
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The inlet pressure of the system is approximately 2.1 MPa, and the outlet pressure is about 15 MPa. A reciprocating three-stage compressor is used; how should the compression ratios for each stage be distributed?
Talking solely about pressure is too vague; the specific pressure ratio distribution can only be determined through detailed calculations. Normally, the pressure ratio per stage does not exceed 3. The pressure ratio allocation principle is as follows: 1. The exhaust temperature of each stage shall not exceed the specified value; API618 stipulates that the exhaust temperature for hydrogen-rich gases (with a molecular weight of less than 8) shall not exceed 135°C, while for other gases, the exhaust temperature generally should not exceed 150°C. 2. The overall piston force per stage should be as similar as possible. 3. The reverse angle at each level is greater than 70
If three-stage compression is determined, first calculate the cylinder diameter based on the isobaric compression ratio, then round it off. After rounding, recalculate the inlet and outlet pressures for each stage to finally determine the compression ratio for each stage
Level 1: 2.19, Level 2: 2.0, Level 3: 1.6 – I’m not sure if these values are appropriate