Gas Plant Recompressor Suction Pressures
Gas Plant Recompressor Suction Pressures
(OP)
I am looking at a cryogenic gas plant that is moving about half the amount of gas it was designed to.I would like to use the excess HP that I have in my recompressors to to lower my plants tower pressure thus cooling the plant and increasing my liquids recovery. The compressors are single stage recips.
How can I reconfigure the compressors? I will have the same discharge pressure, Same HP, less volume, and lower suction pressure than the original design.
Thanks in advance.
How can I reconfigure the compressors? I will have the same discharge pressure, Same HP, less volume, and lower suction pressure than the original design.
Thanks in advance.





RE: Gas Plant Recompressor Suction Pressures
Johnny Pellin
RE: Gas Plant Recompressor Suction Pressures
Single stage machines are pretty easy, but not trivial. The compression cylinder can do about 4.5 compression ratios Which means that the discharge pressure (in absolute terms) divided by the suction pressure (in absolute terms) is less than 4.5. If you go over 4.5 ratios, then you risk discharge temperature and rod-load problems. If you put your new conditions in and the program likes it, then you can move forward. If the program has any errors or warnings then you should resolve them prior to making the change.
The two parameters that you have to pay special attention to are discharge temperature and rod load. Rod load is kind of tough to measure, but most compressors have a way of seeing the sucction temp. You'll usually want this below 300F, and it is common for compressor-kills to be set slightly above this value.
If this all sounds too hard, then you can either go to your packager or the Mfgr and have them evauluate the change or you can hire one of us consultants to give you inconclusive answers.
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
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RE: Gas Plant Recompressor Suction Pressures