Q & A > Question Details
We are fixing for choosing a new compressor for VRU; vapors recovery unit; the light hydrocarbon gas mixture has Mw about 42, K{Cp/Cv} =1.12 , Rc {Pd/Ps} =3.2 , Z factor is about 0.97, Inlet temperature is 43 C and flow rate Q is 600 CFM, discharge Pressure, Pd= 72 psia...
I'd be more than grateful for any tips, Equations, etc to use...
27/10/2010 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
Specify the type of compressor, or solicit bids on multiple types. Most of the entrees on a Request For Bid data sheet are important. I won’t go through the data sheets here. From an operational viewpoint, I will suggest the following features if it is to be a reciprocating machine with a spare:
1) Request manual unloading pockets.
2) Request top suction. That makes it easy to provide a piping layout capable of “flying switches” without waiting for suction line draining.
In this service it is important to allow for swings in flow rate or composition. Simply review the compressor curves as quoted and select one where the operating point is not near the maximum.