vibrations in reciprocating compressor-ethylene gas

[kkdesai]

Request to provide more information or case study on vibrations caused by pulsations in a reciprocating compressor for ethylene gas. we experienc this problem in a single stage double acting double throw compressor operating at around 424 rpm. higher vibrations at the pipelines. would aprreciate your advise, co-operation, support

 

[TD2K]

I know of one compressor that was had new cylinders installed to increase its capacity and had vibration problems after startup, found out the wrong counterweights for the pistons had been shipped.

You don't provide much information (fixed speed, variable speed, has the problem always been there, etc). You really need to look at the vibration and other problems to first see if that gives you any idea to the possible causes. An acoustical analysis of the entire piping system and compressor might be an option if it hasn't already been done, that will tell you if piping, orifices and pulsation dampners have been correctly sized.

 

[pmover]

general comments, thoughts, etc . . .

recip compressors generate a pulse wave that is transmitted through the piping system (can be upstream and downstream of compressor). the pulse wave will continue to travel through the piping system until the wave is dampened or attentuated. generally, the pulsations are dampened/attentuated at or near the compressor.

in your case, you state the higher levels of vibration are at the pipeline. think of this, a pulsation wave is generated at the compressor (presumably the discharge) and travels through equipment and pipe of varying diamters(?) and gets to the pipeline. as the pulse wave strikes piping bends (elbows, tees, etc), this creates movement of the pipe. also, large diameter pipelines are generally not anchored as frequently as smaller diameter pipelines.

as TD2K recommends, an accoustical analysis/pulsation study may be an option.

hope this helps!
good luck!
-pmover