David J. Sager
In order to select a compressor, or calculate the performance of a compressor, certain design criteria must be known. This criteria is listed below: 1. Gas analysis. A gas analysis is preferred, but if one is not available, then the specific gravity or molecular weight, n value, critical pressure and critical temperature of the gas can be used. 2. Capacity. This is generally given in either MSCFD or MMSCFD (Thousand Standard Cubic Feet Per Day or Million Standard Cubic Feet Per Day) at a given base pressure and temperature. (Example: 14.65 PSIA & 60_F). 3. Inlet temperature. At the compressor inlet. 4. Inlet pressure. At the compressor inlet. 5. Discharge pressure. At the compressor outlet. 6. Elevation. At the compressor location. Assuming values for the above design criteria, calculations can be made to either select a compressor, or calculate the performance of an existing compressor.