To: Laurel Dygowski (EPA-Region 8) From: Bradley Nelson, EC/R Incorporated Date: July 17,2009 Subject: Four-FactorAnalysis ofControl Options for Devon Energy

- Blaine County #1 Compressor Station

- Chinook, Montana

The DevonEnergy Production Company, L.P. operates a natural gas compressor station that serves as a natural gas gathering, compression, and transmission station. The station gathers field gas and compresses the gas to the required pressure for the natural gas transmission system. The main emission sources from the Devon Station are: (2) 5500 HP Ingersoll-Rand KVR 616 (4-stroke rich-bum) (3) 1140 HP Caterpillar 03516 TALE (4-stroke lean-bum) (1) 297 HP Waukesha L16160U generator (4-stroke rich-bum) The station also has two 0.75 MMBtulhrdehydration units used to remove moisture from the natural gas before it is transported down the pipeline. The Ingersoll-Rand engines are equipped with an automated electronic air/fuel controller and electronic fuel valve with electronic ignition. Each ofthe Caterpillar engines is equipped with a low emissionpackage, which includes a leanbumelectronic air/fuel ratio controller. The Waukesha engine is an uncontrolled 4-stroke richbum engine used to provide emergency powerto the facility and generally operates only 75 hours peryear. All ofthese emission sources use pipeline natural gas for combustion, therefore the only significantpollutantthat is emitted is NOx; emissions ofsulfurdioxide (S02), and particulate matter (PM) are negligible. Table 1 summarizes the NOx, S02 and PM25 emissions listed inthe 2002 National Emissions Inventory (NEI) database for the facility. Table 2 summarizes the NOxemissions from each ofthe engines in 2002. Note that the difference inNOx emissions inTables 1and 2 are due to the emission from the auxiliary processes (i.e., the 2 dehydration units) at the facility. These auxiliary sources are consideredto be too small to apply control technology and will not be analyzed inthis report.


### Table 1. 

### Summary ofPollutant Emissions (2002 NEI) Devon Energy - Blaine County #1 Compressor Station

NO

### x (Ton/yr) SOl 

### (Ton/yr) PM l .5 

### (Ton/yr) 1,155 

# o oThe facility provided information onthe operating engines in their response to the Section 114 letter. I Controlled emissionfactors from a 2002 stack test were used to calculate the 2002 annual emissions from each ofthe engines and evaluate the control effectiveness ofthe retrofit control options for the enginesthat were evaluated.


### Table 2. Summary of2002 NOxEmissions

- Devon Energy Blaine County#1 Compressor Station


### Emission Hours of Controlled Engine Rate Operation Emissions (gnIP-hrt (hr/yrt (tons/yr) Ingersoll-Rand KVR 616 (Unit 1) 11.9 8,599 620 Ingersoll-Rand KVR 616 (Unit 2) 9.819 8,603 512 Caterpillar G3516 TALE (Unit 4) 0.899 8,427 9.52 Caterpillar G3516 TALE (Unit 5) 0.895 8,571 9.64 Caterpillar G3516 TALE (Unit 6) 0.573 8,714 6.27 Total 1,157
a Response to Section 114 letter from Tracy Carter, Regional Vice President, Devon Energy Production Company, to Laurel Dygowski, U.S.EPA

- Region 8. June 18,2009.
The facility provided information on control efficiency ofthe combustion modifications, which they stated as 90% for the Ingersoll-Rand engines and 100% for the Caterpillar engines. However, for the Ingersoll-Rand the listed controlled emission rate was greaterthan the uncontrolled rate, therefore no control efficiencies for these engines could be calculated. Based on the controlled and uncontrolled emission rates for the Caterpillar engines, the control efficiencies were calculatedto be 88, 88, and 93% for Units 4,5, and 6 respectively. As shown in Table 2, the significantNOx emission sources from this facility are Engines 1 and 2. The facility noted in theirresponse thatthese engines (l and 2) wouldbe operated only 50% ofthe time in the future, which would reduce theirNOx emissions to 316 and 261 tons per

.year respectively. Even at these lower annual hours ofoperation, these engines are still significant sources ofNOx emissions. The only effective NOx control option for these engines wouldbe the retrofit ofnon-selective catalytic reduction (NSCR), orthree way catalyst. In NSCR, the engine exhaust is routed to a catalyst bed across whichNOx is reduced to nitrogen gas. Atthe same time, volatile organic compounds (VOC) and carbon monoxide (CO) are oxidizedto water and carbon dioxide (C02), This technology has proven to be effective and can reduce NOx emissions from rich-burn enginesto an emission rate of0.15 grams per horsepowerhour (g/HP-hr). The low emission packages onthe three lean-burn engines are the most effective

I Response to to Section 114 letter from Tracy Carter, Regional Vice President, Devon Energy Production Company, to Laurel Dygowski, U.S.EPA

- Region 8. June 18,2009. 2

### NOx controls that can be used for these engines. Therefore, no othercontrol options will be examined for these engines. 

### Factor 1 - Costs Based on the information supplied by the facility the only candidates for control technology are the two Ingersoll-Rand KVR 616 rich-bum engines (Engines 1,2). Table 3 providesthe control option which was identified for natural gas-fired lean-bum engines. The NOx control options for rich-bum engines are limited because ofthe oxygen levels in the exhaust gas stream. The only feasible NOx control option for rich-bum engines is the use ofNSCR. Table 4 provides a summary ofthe capital and annual costs for retrofitting each ofthe control options. The capital and annual costs were estimated using a control cost memorandum developed for the Reciprocating Internal Combustion Engine National Emission Standards for Hazardous Air Pollutants (RICE NESHAP)? Capital cost data for five generic sized engines were received from a manufacturer ofthe SCRtechnology and used to develop cost equations based on the size (i.e., horsepower) ofthe engine. The installed and annual costs were**develo~ed** 

### using the Office ofAir Quality Planning and Standards (OAQPS) Control Cost Methodology. The annual cost includes the amortization ofthe capital cost ofthe control equipment over 20 years at an interest rate of7%. Table 4 also presents the cost effectiveness for each control measure, in terms ofthe cost per ton ofemission reduction
.. Table 3. Estimated Costs ofControl - Devon Energy Blaine County #1 CompressorStation
Potential Pollutant 2002 Baseline Emissions

### • Estimated Control Controlled Emissionsb Source Name Source Type controlled Control Option (tons/yr) Efficiency (%) (tons/yr) Devon Energy ­ 5500 HP Ingersoll-Rand Unit 1 KVR 616 natural gas-fired 4-stroke rich-burn NOx NSCR 620.4 99 612.6 compressorengine Devon Energy­ 5500 HP Ingersoll-Rand Unit 2 KVR 616 natural gas-fired 4-stroke rich-burn NOx NSCR 512.1 98 504.3 compressor engine

a Baseline emissions obtained from Table 2. b Potential controlled emissions calculated assuminga controlled NOx emission rate of0.15 g/HP-hr.

2 Memorandwn from Bradley Nelson, AGTI to Jamie Pagan, EPA Energy Strategies Group, Control Costs for Reciprocating Internal Combustion Engines at Major and Area Sources, April 28, 2006. EPA-HQ-OAR-2005-0030­ 0005. 3 EPA Air Pollution Control Cost Manual Sixth Edition, EPA/452/B-02-001, January 2002. http://www.epa.gov/ttnlcatc/dirl/c alIchs.pdf 3Table 4. Estimated Costs ofControl - Devon Energy Blaine County #1 CompressorStation

Engine Unit 1 Pollutant Controlled NOx Control Option Current system Estimated Control Efficiency (%) N/A Estimated Capital Cost ($) 790,000 Estimated Annual Costa ($!yr) 6,500 Cost Effectivenessb ($!ton)

N/A NSCR 95 221,600 32,700 53.4 Unit2 NOx Current system N/A 790,000 6,500 N/A NSCR 95 221,600 32,700 64.8

a The annual cost was calcul ated usi ng a 20-year equi pment Iife and 7% interest. b Cost effectiveness calculated usingthe estimated annual cost and the potential controlled emissions.



### Factor2 - TimeNecessaryfor Compliance The Institute ofClean Air Companies (ICAC) has estimatedthat approximately 6 months is required to design, fabricate, and install NSCRtechnology for NOx control.4 Additional time ofup to 12 months may be required for staging the installationprocess ifmultiple engines are to be controlled at a single facility. Based onthese figures, the total time required to achieve emission reductions for an engine is estimatedto be a total of 112 years for NOx strategies.


### Factor3 - Energyand Non-Air Impacts Installation ofNSCRonthe rich-burn engines are not expected to increase fuel consumption, however, there will be an increase in CO2 emissions. In addition, spent catalyst would have to be changed periodically, producing an increase in solid waste disposal. However, many catalyst companies acceptthe return ofspent catalystmaterial, where they are regenerated on-site and used again. 5

4 Institute ofClean Air Companies (2006), Typical Installation Timelines for NOx Emissions Control Technologies on Industrial Sources. 5 Letter and attachments from Smith, J. C., Institute ofClean Air Companies, to Neuffer, W. J., EPA/ISB. May 14, 1992. Use ofcatalyst systems with stationary combustion sources. 4

### Factor4 - Remaining Equipment Life The rich-bum engines were noted by the facility to have an expected equipment life of5 to 25 years from present. Therefore, it was assumed for this analysis that the engines will notbe retired prior to the amortization period (20 years) for the specific control equipment.

5