Reciprocating Compressor Seals Reciprocating Compressor Seals Partner Savings From Partner Savings From

Compressor Rod PackingCompressor Rod PackingPresented toPresented to

2005 EPA Star Conference - Midland2005 EPA Star Conference - Midland

June 8, 2005June 8, 2005

Jim Rauh, Compressor EngineeringJim Rauh, Compressor Engineering

Rick Loveless, Northern Natural GasRick Loveless, Northern Natural Gas

Engine and CompressorEngine and Compressor

Discussion PointsDiscussion Points

Standard packing casesStandard packing cases How packing worksHow packing works Impediments to proper sealingImpediments to proper sealing Packing case leaksPacking case leaks Northern Natural case historiesNorthern Natural case histories Low Emission Packing (LEP)Low Emission Packing (LEP) Summary/Q and ASummary/Q and A

Compressor Cylinder Cut AwayCompressor Cylinder Cut Away

Standard Packing CaseStandard Packing Case

Pressure Activates PackingPressure Activates Packing

Impediments to Proper SealingImpediments to Proper Sealing

Ways packing case can leakWays packing case can leak Nose gasket (no crush)Nose gasket (no crush) Packing to rod (surface Packing to rod (surface

finish)finish) Packing to cup (lapped Packing to cup (lapped

surface)surface) Packing to packing Packing to packing

(dirt/lube)(dirt/lube) Cup to cup (out of Cup to cup (out of

tolerance)tolerance)

What makes packing leak?What makes packing leak? Dirt or foreign matter (trash)Dirt or foreign matter (trash) Worn rod (.0015”/per inch dia.)Worn rod (.0015”/per inch dia.) Insufficient/too much lubricationInsufficient/too much lubrication Packing cup out of tolerance Packing cup out of tolerance

(+.002”/-.000”)(+.002”/-.000”) Improper break-in on startupImproper break-in on startup Liquids (dilutes oil)Liquids (dilutes oil) Incorrect packing installed Incorrect packing installed

(backward or wrong type/style)(backward or wrong type/style)

Typical Packing Leak PathsTypical Packing Leak Paths

Leakage RatesLeakage Rates

Packing is designed to Packing is designed to restrictrestrict leakage leakage Fugitive natural gas emissions result in Fugitive natural gas emissions result in

significant loss of revenue/greenhouse gassignificant loss of revenue/greenhouse gas Average rod leak rate is .98 to 1.86 scfm Average rod leak rate is .98 to 1.86 scfm

(28-53 liters/minute) based on Pipeline (28-53 liters/minute) based on Pipeline Research Committee findingsResearch Committee findings

Northern Natural/CECO Northern Natural/CECO Historical Data on Units A/BHistorical Data on Units A/B

Monitored emission units are methane Monitored emission units are methane leakage in liters/minute for two locationsleakage in liters/minute for two locations

Testing is still in progress, current 3 months Testing is still in progress, current 3 months leak rate shows zero leakageleak rate shows zero leakage

Unit A leakage as high as 301 liters/minUnit A leakage as high as 301 liters/min Unit B leakage as high as 105 liters/minUnit B leakage as high as 105 liters/min

NNG Unit A/B Leakage Rates NNG Unit A/B Leakage Rates

0

50

100

150

200

250

300

350

1997 1998 1999 2000 2001 2002 2003 2004 2005 LEP

Unit AUnit B

NNG Packing Leakage NNG Packing Leakage Economic Replacement Point Economic Replacement Point

Approximate packing replacement cost is Approximate packing replacement cost is $3000 per compressor rod (parts/labor)$3000 per compressor rod (parts/labor)

Assuming gas at $5/MCF: 1CFM=28.316LAssuming gas at $5/MCF: 1CFM=28.316L– 50 liters per min/28.316=1.766 scfm50 liters per min/28.316=1.766 scfm– 1.766 x 1440min/day=2543 scf per day1.766 x 1440min/day=2543 scf per day– 2543/1000=2.543 MCF2543/1000=2.543 MCF– 2.543 x 365 days= 928MCF per year2.543 x 365 days= 928MCF per year– 928 x $5MCF=$4640 per year leakage928 x $5MCF=$4640 per year leakage

Here Is the SolutionHere Is the Solution

Low emission packing (LEP) overcomes Low emission packing (LEP) overcomes low pressure to prevent leakage.low pressure to prevent leakage.

The side load eliminates clearance and The side load eliminates clearance and maintains positive seal on cup face.maintains positive seal on cup face.

LEP is a static seal, not a dynamic seal. No LEP is a static seal, not a dynamic seal. No pressure is required to activate the packing.pressure is required to activate the packing.

This design works in existing packing case This design works in existing packing case with limited to no modifications required.with limited to no modifications required.

LEP Packing Configuration

Orientation in CupOrientation in Cup

Reasons to Use LEP Reasons to Use LEP

Upgrade Upgrade is very inexpensive.is very inexpensive. Significant cost savingsSignificant cost savings and reduction of and reduction of

greenhouse gas are major benefit.greenhouse gas are major benefit. Refining, petrochemical and air separation Refining, petrochemical and air separation

plants have used this design for many years plants have used this design for many years to minimize fugitive emissions. to minimize fugitive emissions.

Should the natural gas industry follow suit?Should the natural gas industry follow suit?

What’s in Your Packing Case?What’s in Your Packing Case?

Consult with operations to verify your Consult with operations to verify your current packing case configuration.current packing case configuration.

What are the current leak rates?What are the current leak rates? Typical LEP conversion is around $125 and Typical LEP conversion is around $125 and

with gas at $6 MSCF, packing case leakage with gas at $6 MSCF, packing case leakage should be identified and fixed.should be identified and fixed.

Monitoring emissions reduces greenhouse Monitoring emissions reduces greenhouse gas release.gas release.

Reduce Fugitive EmissionsReduce Fugitive Emissions

SummarySummary

Packing is a dynamic seal designed to Packing is a dynamic seal designed to restrict leakage.restrict leakage.

Verify your current leakage rate.Verify your current leakage rate. Low Emission Packing (LEP) is an Low Emission Packing (LEP) is an

inexpensive conversion to reduce fugitive inexpensive conversion to reduce fugitive emissions.emissions.

Questions?Questions?

Thank you!Thank you!