2 replies to this topic

[GSaikrishn]

Dear Sirs,

at our refinery section we have an oil injected screw compressor which compresses fuel gas to downstream header pressure.

Im not exactly sure as how to go about estimating the performance of the compressor.

Operating parameters are as follows:

Suction temp: 40 deg c

Discharge temp: 100 deg c

Suction pressure: 0.45 Kg/cm2(g)

Discharge pressure: 5 Kg/cm2(g).

Mol wt: 17-18

Flow: 17-18 TPH.

Now efficiency of the compressor is one of the indicating parameters for performance, however no method is available to estimate the efficiency.

Really appreciate if u could suggest some literature so that i can go ahead with my calculations.

Regards
Saikrishna

[Art Montemayor]

Saikrishna:

You know the compressor is presently operating, so you know its condition, its present performance, its age, its manufacturer, its model and size, its connected driver and power consumption. You should also have a copy of the machines name plate, that gives you the size and serial number.

With all that information, what I would do – if I needed the mechanical efficiency of the machine – is to pick up the phone or generate an email to the manufacturer and ask for the specific information you require.

[ankur2061]

Saikrishna,

Art Montemayor has given you very good advice by asking you to get in touch with the machine manufacurer to ascertain the efficiency of your oil flooded compressor. Having said that, we also know that the efficiency of a machine decreases over a period of time due to wear and tear.

A few fundamental facts related to effiiciency of rotary compressors are as follows:

Volumetric efficiency of any rotary compresor is a function of the tip leakage past the rotors. This leakage is termed as slip. Slippage is a function of the rotor diameter and the differential pressure for a given gas.

A very good article on oil flooded rotary screw compressors provides the formula for volumetric efficiency as a function of the gas volume trapped between the rotor and casing when the rotor is in zero-sweep position and the compression ratio. Below is the link for the article:

http://docs.lib.purd...ew compressors"

Hope this helps.

Regards,
Ankur.