Analysis of changes in gas turbine compressor operation in gas processing station from parallel to series using aspen hysys

Parallel compressor gas operation mode is used when the natural gas pressure is still sufficient with one compression stage to reach high pressure; if the gas feed pressure is below the compressor design pressure, it is necessary to increase the pressure to two stages. The purpose of this study was to analyze the effect of changing the gas turbine compressor operating mode from parallel to series due to a decrease in gas well pressure. The ability of a compressor to compress gases under its design pressure can be simulated with a simulator. Parallel compressor operation can be simulated as two-stage compression by being connected in series using the ASPEN HYSYS. The simulation results of the compressor suction pressure drop from 318 psig to 200 psig at the compressor unit at the natural gas processing station of PT. Z show the compressor performance curve is still stable and far from the surge line when used in series operation mode. Recalculation of the surface facilities of the separator and scrubber units shows that the fluid retention is still under 5 minutes, the velocity and momentum of the fluid in the vessels are still below the maximum capacity of the equipment, and the required cooling load is still below the available duty coolers. In the piping system, when operating under compressor design pressure, the fluid velocity value is still below the pipe erosion velocity (for two-phase flow), while for single-phase flow it is below 60 ft/s for the gas phase and 15 ft/s for the liquid phase. Based on the simulation carried out and recalculation of the feasibility of surface facilities, changing the compressor operating mode from parallel to series is feasible and can be carried out safely.