high discharge temp of air compressor

[terrorist]

Hi all
we have a khosla make air compressor installed in our unit. Its a two stage double acting reciprocating compressor. Discharge of 1 st stage is passed through a water cooled inter cooler and outlet is fed to second stage.
Generally we encounter with 2nd stage high temp problem while 1st stage outlet temp remains within limit. jacket cooling water inlet and outlet temp are also within limit.We have a doubt that that may be some scale formation in jackets and piping. We clean the jackets during the scheduled preventive maintenance done every six month. Now should we go for cleaning of piping also??

 

[zdas04]

Has first stage discharge pressure changed? I often see first stage valve leakage lower the discharge pressure of the first stage. That makes the second stage suction pressure lower so in order to open the second stage discharge valve, the second stage has to do more ratios which increases the heat of compression.

Fouling in the interstage cooler can also lower second stage suction pressure.



David Simpson, PE
MuleShoe Engineering

Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat

 

[terrorist]

thanks zdas.
1st stage discharge pr. is on higher side instead. outlet temp of inter cooler is also within limits so fouling in inter cooler can not be thought of.
At least one thing is clear that if the suction pr of a reciprocating compressor is low, discharge temp will be high.
right??

 

[zdas04]

That is right. If first stage discharge is normal pressure and temperature I would next look at sticking valves in second stage suction. If the valves stick then they open late (with lower pressure in the cylinder than you expect) and the actual compression ratios go up.

David Simpson, PE
MuleShoe Engineering

Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat

 

[racookpe1978]

What is your trend of water inlet and outlet condition and temperature?
Is your air compressor issues (the high temperature) ever seen before at summertime higher water cooling temperatures?

Anything different in other parts of your cooling system? you mentioned a 6 month cleaning of the AC HX, what about the rest of the system: cleanliness and flows the same elsewhere?