Pulsation study when you modify piping system on Reciprocating compressor discharge line?

[Chengin]

Hi, I'm chemical engineer working in a refinery.
I'm working on a revamp project which installing some new equipment in existing process.
New piping route will be added for it and the tie-in point is somewhere on discharge line of reciprocating compressor.
We are not modifying existing compressors but the operating conditions will be changed a little bit.
We have original pulsation study data, but it has been about more than 25 years.

So I'm wondering that if I should do pulsation study even though we are only modifying lines related to the compressors.
I think pulsation study should be done because they are really old compressors and the operating conditions will be changed.
Because I'm not an expert on this field, please let me know about below..
(There are 3 compressors which design discharge pressure is about 200bar and composed of 3 stages.)

1. Normally, is it essential to do pulsation study when you modify piping systems?
2. In this case, should mechanical input data for pulsation study be changed because it's been years after first operation?
3. Any opinions or advice for this case.

Thank you for reading my question.

 

[saplanti]

It depends on where the tie-in location ıs.The pulsation effect is very strong after the pulsation bottles until ıt meets a large volume and orıfıces for the purpose of the reduction of pulsation. More or less, for DN 150 or DN 200 discharge lines, around after 200 m might be sufficient for the new tie-in location without another pulsation study. I write this from my previous experience. In case the tie-in is before the large volume ıt definitaly will require another pulsation study.

I would think about the tie-in type as well. 90 deg tee connection might be problem. This type connection will be verified by the study due to the toning effect, vortices and the contribution on the vibrations.

 

[Chengin]

To saplanti
Thank you for your reply.
So, you recommend pulsation study because there will be a new piping system, not because the compressors are old.
Does it have nothing to do with compressor's device life?

 

[saplanti]

There is no straight answer, I guess the pulsation study will solve everything. I tried above to provide you the conditions that you may avoid the study.