SCREW COMPRESSOR SYSTEM FAIL - VERY CURIOUS PROBLEM

[FernandoV1]

Dear All,

I really need your help or ideas about the following issue.

In our gas plant we provide air to the instrumentation by a screw compressor (Kobelco-oil free with 2 stages)at 7 bar(102.9PSig), 2021Nm3/h (280m3/h). Last week we have to repair one, so i have to rent another screw compressor ,so i brought a screw compressor with a flow rate of 10m3/min@102.9Psig(600m3/h @102.9PSig)much higher than we required at the plant. The problem was ,when i have connected the new compressor ,the consuming flow rate of the plant(120m3/h) started to goes down and i have never reached the pressure of 102.9psig the maximum pressure delivered was 88.2psig
Even thoug we have corrected the pressure loss , we are still withouht reaching the flow rate and the pressure required by the plant.

The question is why if have rented a screw compressor with a flow capacity much higher than the screw compressor of two stages , the flow rate and the pressure were never reached?

Best regards and wishes

Fernando

 

[chicopee]

I could be wrong but I think the flow rate of 10 cu.meter is at free air delivery; as the line pressure increases the flow rate will decrease.

 

[MikeHalloran]

Ask the rental company to replace that compressor; the screws are probably worn out.



Mike Halloran
Pembroke Pines, FL, USA

 

[FernandoV1]

Dear Chicopee,

When you refer to free air delivery you are talking about air at 60F and 14.7psi? or you are talking about that 10m3/min at 102.9 psi is without load?

Bes regards

 

[chicopee]

Yes,60F at 14.7 psi or atmospheric temperature and pressure.

 

[crjones]

From your initial numbers your rental unit is one third the size of your plant compressor. so no it will not be able to keep up.