I’d like to ask everyone about reciprocating compressors
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I’d like to ask everyone about the air volume, intake pressure, and gas composition of reciprocating compressors How are the medium density, as well as the volume and pressure of gas delivered by the compressor calculated?/What amount is required when using a hydrogen compressor to compress nitrogen? For example, if the final pressure of hydrogen is 10 MPA, what will be the final pressure of nitrogen? What are the minimum pressure and diameter required for nitrogen supply in the pipeline? Why am I getting more and more confused?
Depending on the molecular weight, when the hydrogen compressor operates with the same pressure and temperature at the nitrogen inlet, the inlet flow rate is 1/14 of the originally designed value, and the outlet pressure is also approximately 1/14 of the originally designed value. If the pressure exceeds this range, the transmission mechanism and compression components will be damaged due to forces exceeding the designed load.
That makes sense; the higher the density, the lower the flow rate must be to avoid affecting the proper operation of the compressor.
Only when the inlet pressure of the compressor remains at the rated design value can the outlet pressure of the compressor reach that rated value. Attempting to achieve the rated outlet pressure at low or high inlet pressures will reduce the compressor’s efficiency and increase the power consumption of the motor
The outlet pressure of a reciprocating machine is determined by the back pressure, while the outlet pressure of a centrifugal compressor is related to the molecular weight!
I agree with what was said on the second floor: in some cases, it is the outlet pressure that determines the back pressure
It seems there might be some confusion; different opinions exist. The characteristic of a reciprocating pump is that its volumetric flow rate is constant and equal to rotational speed * piston area * stroke (double-acting: *2). In principle, the pressure is related to the back pressure in the outlet pipeline, but considering the compressor’s power and the density of the gas, when using a hydrogen compressor to produce nitrogen, it’s necessary to take into account the load on the motor. As long as the motor isn’t overloaded, there should be no problems with the compressor components. Generally, the inlet flow rate needs to be converted to a flow rate under standard conditions. What was mentioned on the second floor regarding the inlet flow rate being 1/14 of that for hydrogen actually refers to the inlet pressure being 1/14 of that in hydrogen operation conditions. The outlet pressure can be roughly estimated as inlet pressure * pressure ratio, serving as a reference for operation. This post was last edited by wzk1998 on 2009-4-20 10:02.]
What was said on the 10th floor is correct – the outlet pressure can be calculated based on the inlet pressure. If the gas source is pipeline gas, in many cases it is difficult to maintain the inlet pressure at a constant value.