Compressor Anti-Surge controller 1

[Indy]

Hi
I’m just trying to understand why compressor Anti-Surge controllers take temperature, flow and pressure signals from the suction side and also the discharge side to then modulate a control valve to recirculate a portion of the flow back to the suction side to prevent surge occurring.

I suppose I am asking why are the signals not just taken from the compressor discharge side ? Can’t see what I’m missing.

Thanks

 

[crshears]

Maybe I'm full of it, but what's that basic formula again? Something like PV=nrt, which fleshes out to P1V1/T1=P2V2/T2...or something like that; point being that accurately determining the molecular volume of a gas transiting a compressor requires the measurement of volume, pressure and temperature on both the suction and discharge side of the compressor, with the computed difference between the two forming an index of the amount of compression energy being added to the gas, the latter of which could also be cross-computed by plugging [electrical?] readings into an algorithm that plots the efficiency of the compressor against its prevailing loading...

Bottom line is that each and every one of these inputs is required to calculate and then control the required recirc to a nicety so that surging is prevented while holding down to an absolute minimum the amount of energy lost in meeting this objective.

Already scanning the skies for incoming tomatoes...

Follow-up: just saw this thread

https://www.eng-tips.com/viewthread.cfm?qid=455629

in the Chemical Plant Design and Operations forum, which made me wonder if you might get better responses there...

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]