Relationship between inlet flow rate and molecular weight of centrifugal compressors
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There is a relationship between the inlet flow rate of a centrifugal compressor and its molecular weight; the designed molecular weight for the inlet of the syngas compressor is 11.477. However, due to system modifications, the average molecular weight of the gas entering the compressor has changed to 9.15, which results in the inlet flow rate not reaching the designed value. How can this kind of problem be solved? What is the theoretical relationship between the inlet flow rate of a centrifugal compressor and molecular weight? I would appreciate guidance from those who are more experienced in this field.
Reduce the outlet pressure or increase the inlet pressure.
The backflow can be increased to boost inlet flow
This post was last edited by hyhpsp on 2018-4-8 at 16:32. First of all, your molecular weight has changed, so the orifice flow meter will definitely be inaccurate. As the molecular weight decreases, the actual flow rate displayed will be lower; it is best to recalibrate the flow meter based on the properties of an ideal gas. Secondly, changes in the molecular weight of the gas can affect the performance of the compressor; it is advisable to provide the manufacturer with the actual gas parameters so that they can redraw the performance curves. Under normal circumstances, it is necessary to increase the rotational speed appropriately; based on the owner’s operating conditions, an increase of several hundred revolutions is required, and it’s not clear whether this will reach the maximum rotational speed.
The basic calculation parameters need to be adjusted; if the molecular weight is reduced, the density also decreases, and this will surely lead to errors in the calculated flow rate. The curve definitely needs to be adjusted as well.
In my opinion, the effect of a lower molecular weight on flow rate is far less significant than the effect of pressure. For centrifugal compressors, it is necessary to ensure a sufficient inlet flow (pressure), so the inlet pressure must be increased. What is said on the fourth floor also needs to be taken into account.
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