Reciprocating compressor help

1. Jul 12, 2010

christwllms

I have a 2 stage reciprocating compressor that is set at a suction pressure of 120 psi and discharging at the second stage of 1160 psi. currently I have gas going in at intermediate pressure at 400 psi compressing about 15 mmscfd. My questions are this:

1. Will the compressor handle it if I take that 400 psi gas and put it into the low pressure stage (120 psi)?

2. Will the flow rate for the compressor remain the same?

2. Jul 13, 2010

Q_Goest

Can you clarify where you're introducing the 400 psi? Is it presently bypassing the 1'st stage and going into the second stage? Or are you putting it into the first stage?

For a recip machine, the flow rate will increase as inlet pressure increases assuming the machine can handle the pressure, which generally isn't a good assumption. Flow for a recip is just density times displacement.

3. Jul 13, 2010

christwllms

Currently the 400 psi is is bypassing the 1st stage and going into the 2nd stage. I'm looking at taking the 400 psi off of the 2nd stage and put it into the 1st stage. Do you have to adjust the suction pressure on the the 1st stage or will the suction pressure raise due to the increased inlet pressure or do nothing at all.

4. Jul 13, 2010

Q_Goest

Sorry, I don't understand what you're trying to do. You have 400 psi (air? what's the gas?) going into the second stage right now but what's going in the first stage? Do you have 120 psi gas going into that? Then all of the gas is going through the 2'nd stage and out at 1160?

Sounds like you want to introduce 400 psi into the first stage, but that would have to be let down through a regulator or something so you don't get 400 psi at the inlet of the first stage... unless the machine is made to handle it which isn't clear.