Compressor surge condition issue
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Generally, compressors are prone to surge at high pressure ratios and low flow rates. For example, in a catalytic rich gas compressor, when the hydrogen content is high the compression ratio decreases; why does surge still occur?
Please read carefully about the principle of surge; you need to strengthen your learning! The forum has a lot of information on this topic!
The flow rate of the compressor is related to the polytropic compression work; the greater the polytropic compression work, the lower the flow rate, and the closer it is to the surge region. The higher the compression ratio, the higher the gas temperature and the smaller the molecular weight of the gas. As a result, the variable compression work required to move the gas from low pressure to high pressure increases, and the flow rate of the compressor decreases. Hydrogen has a molecular weight of only 2, so the variable compression work required for compression is very high; even with a relatively low compression ratio, surge can still occur. For example, the new hydrogen compressors in hydrocracking and hydrofining units both use reciprocating compressors rather than centrifugal compressors, as the high compression ratio and very low molecular weight result in excessive polytropic compression work, making centrifugal compressors unsuitable for such applications.