Reciprocating Compressor Pulsation Control Design requirements

[cowpen]

I have a reciprocating compressor (2-stage vertical, double acting) for nitrogen services that is used to boost up the nitrogen pressure from about 5 barg to 35 barg, with a flow of 1000Nm3/hr. I’m trying to understand the basis of pulsation control that should be used for this reciprocating compressor.
I am aware of the API 618 & API 688 preliminary sizing for pulsation control which gives the minimum required surge volume for the suction and discharge of the compressor. II would like to get further input regarding the following:
1. Can a moisture separator/ surge drum be considered as a pulsation damper?
2. Can the 1st stage discharge and the 2nd stage suction share the same pulsation bottle? (is this specified anywhere in any code and standard)
3. Are there any rules of thumb regarding requirements for the distance between the compressor flange to the pulsation bottle?
4. Can orifices be used for pulsation control in lieu of pulsation bottles?
Would appreciate if anyone can point me toward references/literature that I can look into that may address this.

 

[LittleInch]

From what I've seen, pulsation control is a field of its own with analysis tools which need to model a lot of your piping system to locate and size the correct pulsation dampers.

If by 1st and 2nd stage you mean one stage feeds the second directly then I can't see how you can separate the two for interstage pulsation.
Generally you put the pulsation bottles close to the inlet and discharge of the compressor.
Orifices won't do very much for you and could make it worse.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[pmover]

pencwo,

do not duplicate your postings, a site policy.

best to keep posting in "gas compression" forum.

 

[georgeverghese]

Pulsation bottles for gas service have some special internals, so 2phase separators wont do.

 

[cowpen]

littleinch, you're right that the first stage cylinder would feed into the 2nd stage cylinder. My understanding is that the normal configuration for the pulsation bottles are as such:
1st stage suction pulsation bottle -> 1st stage compressor -> 1st stage discharge pulsation bottle -> interstage cooler -> 2nd stage suction pulsation bottle -> 2nd stage compressor -> 2nd stage discharge pulsation bottle -> discharge cooler. I'm trying to understand if it is possible to combine the 1st stage discharge & 2nd stage suction pulsation bottle into a single surge volume.

pwmover, got it. will delete the other one since this thread seems to be getting a little more traction.

georgeverghese, noted on the pulsation bottle internals. From what I'm reading- the pulsation bottles typically have a Helmholtz resonanator installed which functions primarily to filter out lower frequency pulsations. In this case, it does make sense that a simple separator may not sufficiently be able to function as a pulsation bottle.

Thanks all for the feedback, appreciate it.





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"It is possible to commit no mistakes and still lose. That is not a weakness; that is life."

 

[LittleInch]

You didn't mention the intercooler....

That will make it harder to combine the two bottles.

This is in my experience a specialised analysis which has to consider the upstream and downstream piping configuration which is the real reason you're doing this to stop the pipe jumping and jumping around.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[pierreick]

Hi,
You may find pointers in the link attached.

https://aciservices.com/wp-content/...sor-Pulsation-Control-Using-PANTM-Filters.pdf

Pierre

 

[cowpen]

thanks littleinch, pierreick for the input, much appreciated

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"It is possible to commit no mistakes and still lose. That is not a weakness; that is life."