1 reply to this topic

[meetyourmaker]

we have an oil flooded screw compressor for propylene refrigeration service that trips frequently on high discharge temperature(78 deg c, ) ,usually when the plant is running at turndown. What changes do u guys think can be made to lower the discharge temperatures(lowering suction pressure,increasing economizer duty etc). I have also noticed that propylene coming to the compressor from the evaporators is sometimes highly superheated at the suction conditions. what could be the possible reason?

Edited by petrochemical, 05 July 2011 - 04:59 AM.

[acer_asd]

Dear petrochemical

It would be more helpful for us to understand your problem if you supply more information like PFD, P, T @ normal and turndown conditions.

As compression is a polytropic process so if you decrease P2/P1 (discharge pressure/suction pressure), T2/T1 (discharge temperature/suction temp) will decrease. So if you could increase the suction pressure or decrease the discharge pressure, discharge temperature should come down.

Regarding problem of superheated vapors, it seems that propylene flow in the system is not sufficient, that's process is giving in more heat to propylene, in turn, superheating it.

Hope this solves your problem

Have a nice day