Process Description
ThThe SPM-1400 Centrifugal Compressor Process Simulation can be configured to compress a variety of process gases by varying the molecular weight. The default configuration is for dry air.
Air passes through a suction valve before entering the suction drum. If the process gas demand is less than the minimum recommended compressor flow (surge point), then the makeup gas will mix with the kickback flow. The gas then passes through a cooler, where the temperature is lowered to prevent excessive compressor discharge temperatures. Any condensate present in the gas will be knocked out in the suction drum before the gas enters the compressor.
The compressed gas is then drawn off from the discharge side of the compressor by users. In the event of a decrease in process gas demand by the users, a minimum compressor flow line (kickback or spillback) is provided to allow the recycling of gas to prevent compressor surging. A vent/flare line is also provided to prevent an over-pressuring of the system.
Approximately 500 MSCFH of air is to be compressed from a suction pressure of 250 PSIG to a discharge pressure of 500 PSIG. All of the gas is sent to a downstream process which is maintained at 375 PSIG. The compressor speed required to accomplish this task is 5343 RPM. Compressor suction temperature is maintained at 100 Deg F, and the compressor discharge temperature is 260 Deg F.
Instrumentation
Flow to the suction drum is maintained by suction pressure controller PIC-301. The suction flow is indicated by FI-101. Supply gas pressure and temperature are indicated by PI-101 and TI-101 respectively. The supply gas block valves can be opened and closed with switches HV-101 and HV-102.
Kickback flow, which is indicated by FI-501, is controlled by FIC-301 which indicates total compressor flow.
Vent/flare flow is controlled by over-pressure controller PIC-701 and is indicated by FI-701. The vent/flare block valves can be opened and closed with the switches HV-701 and HV-702.
Flow to the process is controlled by FIC-601. The downstream process pressure is indicated by PI-601. The process block valves can be opened and closed with the switches HV-601 and HV-602.
Steam flow to the turbine is controlled by speed controller SIC-401. The steam block valves can be opened and closed with the switches HV-401 and HV-402.
Cooling water flow to the cooler is controlled by TIC-202 and indicated by FI-201. Cooling water supply temperature is indicated by TI-203 and cooling water return temperature is indicated by TI-204. The cooling water block valves can be opened and closed with the switches HV-201 and HV-202.
Compressor discharge temperature is indicated by TI-501 and compressor discharge pressure is controlled by PIC-501.