Recip Packing
Recip Packing
(OP)
I'm reviewing some new proposed EPA air regulations (U.S.A) and one of them jumped out at me. For recips in natural gas service after the well site and before the city gate, operators of recip compressors will be required to replace (and document in submittals to the EPA) all compressor packing every 26,000 hours of operation (less than 3 years of continuous operation).
It doesn't mention an acceptable leakage rate or allow alternative methodologies to control emissions (just off the top of my head it seems like the emissions could be reduced to near zero by building a distance piece rated for 3-5 psig and porting the distance piece to a flare or VRU).
Does anyone have a feeling for how long packing is supposed to last? Also, what is the cost to replace the packing on a cylinder and how long would the machine be out of service?
Comments to the agency are due in a couple of weeks so any ideas need to come in pretty soon.
It doesn't mention an acceptable leakage rate or allow alternative methodologies to control emissions (just off the top of my head it seems like the emissions could be reduced to near zero by building a distance piece rated for 3-5 psig and porting the distance piece to a flare or VRU).
Does anyone have a feeling for how long packing is supposed to last? Also, what is the cost to replace the packing on a cylinder and how long would the machine be out of service?
Comments to the agency are due in a couple of weeks so any ideas need to come in pretty soon.
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
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RE: Recip Packing
Dave, let me call someone tomorrow (employed by an P/L operator) and I'll post a response . . . that is if I remember to call. I've got CRS really bad lately . . .
-pmover
RE: Recip Packing
we spoke today and there are variables that impact the longevity of packing (i.e. quality of gas, materials, rod surface, rod drop, material of packing used, etc.). the application/service even has a factor. he suggested contacting CECO (1-800-try-CECO) for further assistance.
btw, his first inquiry/response was whether or not the request had anything to do with the EPA. apparently, he is aware of these "proposed regs" . . . not too favorable either . . .
i've not read the proposed EPA regs - can you post a link (if available).
the distance piece and flaring or using a VRU will be $ - though not a bad idea.
good luck David.
-pmover
RE: Recip Packing
David
RE: Recip Packing
Most of our reciprocating compressors have rods 3 inch diameter or larger. To replace the main pressure packing, I would expect the compressor to be out of service for 2 days or more. I would probably schedule the job for 5 days in case they found any other problems. Some compressors are very difficult to repack around the rod. If the piston and rod has to be pulled, this will obviously increase the time required.
Johnny Pellin
RE: Recip Packing
David
RE: Recip Packing
Johnny Pellin
RE: Recip Packing
David
RE: Recip Packing
Per my interaction with packing OEMs as a compressor engineer, a cylinder packing in good condition will leak approximately .1SCFM . Rod finish, case condition, gas properties and many more factors can influence the above rule of thumb rate.
Regarding methods to reduce emissions, several packing OEMs (CECO, Hoerbiger, COOK) offering static pack which seal both dynamically (during operation) and statically (during shut down). New low emission rings are available to reduce emissions (limited available data). Nitrogen purging is also a viable method to reduce packing leakage.
Brian
Dresser-Rand
RE: Recip Packing