Natural gas compression control method
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Hello everyone: The evaporated gas from the storage tanks is pressurized by a compressor and then sent to the natural gas pipeline network. The compressor has a capacity of approximately 1500 Nm3/h; a reciprocating compressor is used for this purpose. The pressure in the pipeline network varies between 3 and 6 MPag depending on the season and time of day. Question: 1. Maintain a pressure of 6 MPag at the compressor outlet, using a pressure regulation and metering unit to prevent changes in downstream pressure from affecting the operation of the compressor ； 2. Adjust the compressor outlet pressure in response to fluctuations in the pipeline network ； I would like to ask everyone: which method is more reasonable? Does anyone have a similar PID diagram for reference?
Compared to pressure regulation skids that increase output, allowing the compressor pressure ratio to fluctuate with outlet pressure is clearly more energy-efficient and reduces investment costs. However, if the pressure in your downstream pipeline network fluctuates between 3 and 6 Mpa, the range is quite wide; moreover, if such fluctuations occur frequently, it is detrimental to the long-term operation of the equipment. Is the pressure in the pipeline network subject to such large fluctuations? If necessary, it is recommended to use an outlet pressure control valve assembly, which can adjust the outlet pressure in a timely manner according to changes in the pipeline network pressure.
It is good that the compressor outlet pressure remains relatively stable; a relatively simple pressure maintenance scheme can be used, with autonomous pressure regulation based on the upstream pressure being sufficient to address the issue