Hydrocracking hydrogen circulator
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Does anyone know what it means when the medium pressure head in a hydrogen circulation machine is insufficient? What are the impacts?
No, I read an article saying that too high a purity of hydrogen in the system causes insufficient pressure in the hydrogen circulation pump?
As the molecular weight decreases, the discharge pressure capacity of the compressor decreases at the same inlet pressure.
For centrifugal pumps, insufficient head may result in no flow; could this be explained more thoroughly in the case of hydrogen circulation pumps? Will the outlet pressure decrease?
For a centrifugal compressor that has been designed, if its molecular weight decreases, the outlet pressure of the compressor will drop at the same rotational speed and inlet pressure. This is because, when the pressure ratio of the medium remains the same, a medium with a lower molecular weight requires a higher polytropic head. Thus, for media with a low molecular weight, if the inlet pressure remains constant, the energy provided by the centrifugal compressor will be less than the specific energy head of the medium, and the outlet pressure of the compressor will decrease. However, in hydrogenation systems, the inlet and outlet pressures of centrifugal compressors change little, and the pressure ratio remains essentially constant. In such cases, if the molecular weight of the medium decreases, it will result in a reduction in the surge flow rate of the compressor; the operating point of the compressor then comes closer to the surge point, making surge more likely to occur if not operated properly.
I think the main reason is the excessive pressure difference at the inlet and outlet of the compressor; check whether there is a large pressure drop in the reactor, the heat exchanger, and the air cooler. The purity of recycled hydrogen is generally between 90% and 95%, so it has little impact.