New Engineer here, less than 1 year since graduating.
I'm designing an Upstream Central Processing Facility and Tank Battery along with a Gas Lift Compression system. My question is in regard to the Gas Lift Compression system. The gas leaving the processing facility will flow to three packaged reciprocating compressors working parallel. Following this the gas will then flow to three packaged reciprocating Booster compressors working in parallel before the gas is injected.
I am considering adding spillback/recycle valves external to the compressors to prevent a shutdown in the case of process upset downstream (i.e. excess gas volume and pressure). Due to the nature of the system the valves would need to operate under a high differential pressure roughly 900 PSI and 3000 PSI.
In part of my due diligence, I ran a HYSYS simulation reducing the gas pressure by 900 psi across a control valve. I generated 10 Barrels/day of liquid hydrocarbons. For the 3000 psi pressure differential case I generated substantially more liquid. Why am I generating liquid when reducing pressure?
Any input on this Phenomena or my implementation of a spillback valve external to the packaged compressors is appreciated.
Thanks.