Discharge pressure control procedure for screw compressor used to compress fuel gas supplied to gas turbine

摘要

A bypass valve (4) is directed to unload and full load conditions respectively, when discharge gas consumption decreases and increases, based on calculated slide valve position desired value following gain curves of small and large gradients when absolute value of deviation between actual and stipulated bypass valve opening degree is below and above a fixed value. The bypass valve is fixed in a bypass flow path (6) connected between the discharge flow path (3) and the suction flow path (5) of a compressor (1) which has a slide valve (2) for capacity regulation.