Installing a compressor hot gas bypass 3

[deerun75]

I am trying to learn how to design compressor recycles. Is there a standard for that (API, ASME)? How do I determine what part of the suction to connect the recycle line? Any and all assistance will be appreciated. Thanks.

 

[TD2K]

I'm not sure what you are asking. If you can be more specific to your question the better.

Some specifics would be good. What are the process conditions for the compressor? Why do you need a recycle or think you need a recycle stream?

A compressor recycle system to me is process engineering.

 

[SNORGY]

Is it a centrifugal machine or a reciprocating machine? In any case, you would probably want to come back to the suction line upstream of the first stage (or inlet) suction scrubber, inside the isolating block valve.

 

[deerun75]

The compressors are reciprocating types. The recycle is been instaled to eliminate gas given off to the atmosphere during blow downs (emissions control).
Are there calculations to be made? What do I need to find out to make sure that the recycle does not over pressure where it's tied in at the suction art?

 

[Montemayor]

Deerrun:

You either:

1) Don't know anything about what you believe you need; or,
2) Don't know how to communicate what it is that you are trying to state.

You can't "recycle" blowdown gas to the suction side of the same compressor that you are trying (or forced) to blowdown. That is purely ridiculous.

By not furnishing any specific basic data and background information on what you are trying to do, you are hiding the true basic answers. How can any member determine if calculations are required? Hell, you haven't given any basic information to piece together what it is that you are trying to do!

This assignment belongs in the hands of someone who knows at least a little bit of what is needed or what is being asked as a solution. Otherwise, I highly recommend you get started on some reciprocating compressor tutorials as soon as you can. You could hurt other people - besides yourself - by trying to do something you know little about.

 

[deerun75]

Art, I do appreciate your "candid" talk.

Any engineer who works in oil and gas will tell you that installing recycles or hot gas bypass on gas compressors is actually a very common process. It's not rocket science. It's simply to eliminate emissions given off during compressor startup and shutdowns...and reduce EPA title V deviations.

 

[786392]

Dear deerun75 Hello/Good Evening,

Kindly reconsider, as your response is also not really decent/ professionally up to the mark! I assume.

We all should avoid such non-professional attitudes anywhere in technical/professional discussions.

As I understand these only suit where a certain degree of frankness or friendliness has had been prevalent.

Moreover we,if professional and technically knowledgeable in some particular/specific field may not be having 100% professional grip of awareness on various other fields.

Still the expertise/ knowledge should never be disgraced by anyone/ for any reasons and We all must abstain.

Hope you will consider my humble request cool-minded, with positive/healthy feelings.
Thanks in advance!

Best Regards
Qalander(Chem)

 

[pmover]

deerun75,

1) i conducted a search via google for what you wrote and nothing of value was presented that could assist you.

2) the information you provided in original posting is vague and incomplete. hence, the responses you obtained.

3) the respondents in these forum are not your designers. you are presumably educated and trained to conduct such activities yourself. if assistance is needed, post clear and concise questions of problem and objectives.

good luck!
-pmover

 

[deerun75]

Thank you all for the replies. As evident from some responses, some people do not know anything about this practice. I did come here for some help since I couldn't get much online and can't get my hands on reference material. I have researched further and:

1. It is used to reduce emissions during start ups and blow downs...title V
2. It is also used when the compressor is much larger than required for the gas stream...to maintain suction pressure.
3. Install recycles from blow down vent to the suction side - after a check valve, but before pressure instrumentations and controls.
4. A PSV may be installed (not necessary - depends on stream pressures) on the recycle stream
5. Yes, you do carry out a pressure-volume calculation to determine gas volume at discharge pressure and size the recycle line.

I have stumbled across a few compressor recycle problems on this forum and some other ones, but people seem to have little or no experience. I hope I am able to help whoever comes next to inquire about compressor recycle/hot gas bypass.

 

[deerun75]

By the way, it's also used to control compressor surge!

 

[786392]

OK deerun75
Thanks for the update& in a way self responding to your post.
It is a positive/ seems more professional a contribution now, thus You may deserve a pink star


Best Regards
Qalander(Chem)