compressor emissions technology review

7/29/2019 Compressor Emissions Technology Review

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GMRC Eng ine Ana ly zer & Re l iab i l i t y W or k shopNashville, TN

July 27-29, 2011

COMPRESSOR EMI SSI ONS

TECHNOLOGY REVI EW

Cra ig Mar t inApplications Engineering Supervisor

Aleksey Dubrov enskyProject Engineer


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Pot en t ia l Leak Po in t s

Oil WiperPacking

Packing CaseNose Gasket

Between Packing Case Cups

Distance PieceVent/Drain

Outer Head

Gasket

Valve CoverGasket

Valve UnloaderPacking

Packing Case Vent


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Pack in g Leak age Fact or s

Failure to account for em issions escap ing in t o t hed is t ance p iece may result in underestimation of

packing related emissions by up to 4 0 % .- U.S. EPA Natural Gas STAR Reducing Methane Emissions From Compressor Rod

Packing Systems, July 2003

+ + + + + =LEAKAGE AT

FRAMEBREATHER

LEAKAGE AT

SECONDARYDISTANCEPIECE VENT

LEAKAGE AT

DISTANCEPIECE DRAIN

LEAKAGE AT

DISTANCEPIECE VENT

LEAKAGE AT

PACKING CASE

LEAKAGE AT

VALVEUNLOADERPACKING

TOTALLEAKAGE

SECONDARY DISTANCEPIECE DRAIN


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New Em issions Regu lat ions

EPA: Best Available Measurement Methods must beused to measure all greenhouse gas (GHG) emissions

Required by July 31st or September 30th, 2011

Petroleum & Natural Gas Systems of the Greenhouse Reporting Rule:Subpart W (40 CFR Parts 98)

EPA defines GHG as any gas that absorbs infraredradiation

Water vapor

CH4

N2O

CFCs

SF6

CO2 HCFCs

HFCs

PFCs

1

Source: EPA Climate Change Directory http://www.epa.gov/climatechange/index.html1


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For ces Dr iv in g Em ission s Redu ct ion s

New emissions regulations

Currently limited to emissions measurement

Possibly future cap-and-trade restrictions on emissions

Economics

Lost production is very costly

Payback on upgrades typically less than one year

Reliability Increase lifecycle of equipment

Operating efficiency becoming a competitive necessity


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Em ission s Man agem ent

Vapor Recovery System

Channel emissions back to a controlled source

Can be expensive and complicated

Modify Existing Packing Case to Reduce Leakage WAT ring used to restrict gas flow into the vent

Field testing confirms low leakage

Additional frictional heat loading on piston rod

Application temperatures should be reviewed

Low-Friction Seal Technology

Low Leak Packing Technology

Possibly able to utilize existing cases Documented results from years of field applications


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WAT Ring

Side-loaded ring, single-acting

Seals well at low pressures

Vent Rin gs


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Tr ad i t ion a l Pack in g Seal Rin gs

Basic functionality of a single-acting seal ring:

During discharge stroke, high pressure gas enterspacking case

Pressure loads ring against sealing surfaces


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Traditional setup

Several seal rings

Standard vent seal

Outdated design

St an dar d Pr essu r e Pack in g


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Low Leak Pack in g Tech n o log y

More effective seals

Fewer rings required

Years of documented field results

Near-zero leakage

Longer packing life


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Seal Rin gs


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Seal Rin gs


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Seal Rin gs


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Seal Rin gs


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100

150

200

250

300

350

0 500 1000 1500 2000 2500 3000 3500

DISCHARGE PRESSURE ~ PSI

RODTEMPERATURE~F

Conventional Packing

Low Leak Technology

Pist on Rod Tem per a t u r e


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WAT Ring

Side-loaded ring, single-acting

Seals well at low pressures

Vent Rin gs


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Ven t Seal Rin gs

Vent Seal RingUpstream of Vent

Typical Low LeakPacking Design


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Pist on Rod Tem per a t u r e:

Vent -Seal Ring Ups t r eam o f Ven t Cu p

0

100

200

300

400

Standard Packing Vent Seal Ring Upstreamof Vent Cup

Tempera

ture(F)

Test 1

Test 2Test 3


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Low - Fr ict ion Seal Tech n o log y

Restricts gas flow into the vent

Reduced frictional heat on piston rod

Friction causes increased piston rod temperatures

Increased leakage rates

Decreased packing lifespan

Controls leakage in standby mode

Confirmed field and lab results


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FI ELD DATA


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Static cylinders can resultin significant leakage Cylinder 1 8.93 SCFM

$38,675 / yr (based on$8 / decatherm)

* Year based on8,760 run hours

Std. BronzeLow Leak

Low Leak


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It is possible to obtain lowrates (~0.1 SCFM) in

running conditions.

Leak rates are below 0.1

SCFM

* Year based on8,760 run hours

Low Leak

Low LeakStd. Bronze


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A small number of cylinderscan cause a large amount of

the total leakage.

96% of the total packing leakagecomes from Cylinder 1 24

SCFM - ~$100K / yr!


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Distance Piece leakage cancontribute a significant amount

to the total leakage.

23% of the total leakageis coming from thedistance piece vent


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Unknown packing and Low Leak packing maintained

low leak rates. Standard bronze packing hasdeveloped a moderate leak at 12,900 hours.

Std.

Low Leak =

Low Leak =


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Cu m u la t i ve Leak age Com par ison

The area under the curve represents the totalleakage throughout the life of the packing

STANDARD

UpgradedPacking Case

Low LeakTechnology

Standard PackingSeal Rings


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STANDARD




Low LeakTechnology



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STANDARD




Low LeakTechnology


Jus t i f i ca t ionfo r Pack in g

Rep lacement


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Packing case maintenance

Upgrade nose gasket to a spiral wound gasket

Replace existing BD vent rings to a WAT

Lap cups 4 light bands flatness

Verify parallelism of cup faces

Within .001

Verify cup depths & ring clearances Verify rod surface finish

8-12 Ra for induction-hardened rod

6-8 Ra for TC-coated or nitrided rod

Verify packing case alignment Ensure proper bolt tightening procedures

Best Pr act ices


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CASE STUDI ES


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Case St u d y I

Measured packing vent flow

Two identical H2 machines

Five-throw Worthington BDCs

Utilized thermal mass flow meterto gather emissions data

Provided options for emissions

measurement

Permanent installation

Portable installation


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Resul ts


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Case St u dy I I

24 cylinders

Standard packing

Measured packing vent leakage on-site

Changed all cases over to Low Leak technology

Measured leakage after upgrades

Below measurable range of flow meter


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Leak age Com par ison ( SCFM)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Low Leak StandardLeakage


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OTHER EMI SSI ONS

SOURCES


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Dr esser Ran d KVR Un loader


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Before After

Air Cylinder

Rope Packing

Seal

Cartridge

Plug

Actuator Rod

Indicator Pin

Up gr ade t o Seal Car t r idg e


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Com pr essor Va lve

Un load er & Act u at o r


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Jack Bo l t St y le Ret a iner s

Poor sealingaround the jack

bolt results infugitiveemissions, whichcan be hazardous

to people and theenvironment

Potential Leak

Hi h S h R i


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High St r en g t h Ret a in er

Replace the single jam nutwith a multiple jam nutdesign

O-ring around the cagejack bolt provide superiorsealing


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Th an k You !

compressor emissions technology review

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