Hi All,
My query is as follows:
There is a dry screw compressor for off-gas service. The specs that we provided are as follows:
Flow: 7500 Nm3/hr, Suction pressure: 4.1 kg/cm2a, Suction temp: 44 degC, Discharge pressure: 9.1 kg/cm2a.
Composition (mol%): H2: 31 , C1: 2, C2: 2.5, C3: 9, i-C4: 11, n-C4: 28, C6+: 10, H2S: 5.3, H2O: 1.3 and other trace components.
Now, in the plant, the H2 content in the gas is more than design (~ 42 mol%) resulting in a decrease in MW (29 actual vs. 38 in design).
Under such circumstances, the compressor vendor is refusing to start the machine telling that it might damage the machine. However, we have not received any specific input from the vendor, like what parts can get damaged and why?
We have very limited knowledge on screw compressor and so would like to know the following:
1. What kind of damage (if any) is expected in a dry screw compressor for this type of variation in MW?
2. In general, what is the percentage variation in MW that a dry screw compressor can usually handle without any major problem?
Any input will be highly appreciated.
Regards,
Rajarshi