Centrifugal compressor
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There is currently a circulating hydrogen compressor that uses an inverter-driven centrifugal compressor: which parameter should be used to control the inverter signal? Is it the pressure before the compressor, or the pressure after the compressor? Is it the flow rate before the compressor or after the compressor? The drawings returned by the manufacturer indicate that pressure control is to be carried out before the compressor, but the system already has pressure control in place at the circulating hydrogen buffer tank before the compressor. Can this be used to control the frequency of the compressor?
For recycled hydrogen, the pressure difference remains relatively constant; if there is no pressure point at the inlet, the outlet pressure can be used for control. Flow rate is not recommended, as recycled hydrogen contains organic impurities which result in quite inaccurate flow measurements.
In the projects I have worked on, many use the mixed hydrogen flow rate to control the compressor speed; of course, it is preferable for this flow rate to be compensated for temperature and pressure.
If it’s pressure control for the inlet buffer tank, does that mean it should spin faster when the pressure is high? Or adjust what the opening degree of the inlet is?