To: Laurel Dygowski (EPA-Region 8) 

From: Bradley Nelson, EC/R Incorporated 

Date: July 17,2009 

Subject: Four-Factor Analysis of Control Options for Devon Energy - Blaine County #1 

Compressor Station - Chinook, Montana 

The Devon Energy 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 MMBtulhr dehydration 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 of the Caterpillar engines is equipped with a low emission package, which includes a leanbum electronic air/fuel ratio controller. The Waukesha engine is an uncontrolled 4-stroke richbum engine used to provide emergency power to the facility and generally operates only 75 

hours per year. All of these emission sources use pipeline natural gas for combustion, therefore 

the only significant pollutant that is emitted is NOx; emissions of sulfur dioxide (S02), and 

particulate matter (PM) are negligible. 

Table 1 summarizes the NOx, S02 and PM25 emissions listed in the 2002 National 

Emissions Inventory (NEI) database for the facility. Table 2 summarizes the NOx emissions 

from each of the engines in 2002. Note that the difference in NOx emissions in Tables 1 and 2 

are due to the emission from the auxiliary processes (i.e., the 2 dehydration units) at the facility. 

These auxiliary sources are considered to be too small to apply control technology and will not 

be analyzed in this report. 

Table 1. Summary of Pollutant Emissions (2002 NEI)
 

Devon Energy - Blaine County #1 Compressor Station
 

NOx (Ton/yr) SOl (Ton/yr) PMl .5 (Ton/yr) 

1,155 o o
 
The facility provided information on the operating engines in their response to the 

Section 114 letter. I Controlled emission factors from a 2002 stack test were used to calculate the 

2002 annual emissions from each of the engines and evaluate the control effectiveness of the 

retrofit control options for the engines that were evaluated. 

Table 2. Summary of 2002 NOx Emissions - 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 greater than 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 calculated to be 88, 88, and 93% for Units 4,5, and 6 respectively. 

As shown in Table 2, the significant NOx emission sources from this facility are Engines 

1 and 2. The facility noted in their response that these engines (l and 2) would be operated only 

50% ofthe time in the future, which would reduce their NOx emissions to 316 and 261 tons per 

.year respectively. Even at these lower annual hours of operation, these engines are still 

significant sources ofNOx emissions. The only effective NOx control option for these engines 

would be the retrofit of non-selective catalytic reduction (NSCR), or three way catalyst. In 

NSCR, the engine exhaust is routed to a catalyst bed across which NOx is reduced to nitrogen 

gas. At the same time, volatile organic compounds (VOC) and carbon monoxide (CO) are 

oxidized to water and carbon dioxide (C02), This technology has proven to be effective and can 

reduce NOx emissions from rich-burn engines to an emission rate of 0.15 grams per horsepowerhour (g/HP-hr). The low emission packages on the 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.
 

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NOx controls that can be used for these engines. Therefore, no other control 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 

provides the control option which was identified for natural gas-fired lean-bum engines. The 

NOx control options for rich-bum engines are limited because of the 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 of the 

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 of the SCR technology and used to develop cost equations 

based on the size (i.e., horsepower) of the engine. The installed and annual costs were develo~ed

using the Office of Air Quality Planning and Standards (OAQPS) Control Cost Methodology. 

The annual cost includes the amortization of the capital cost ofthe control equipment over 20 

years at an interest rate of 7%. Table 4 also presents the cost effectiveness for each control 

measure, in terms ofthe cost per ton of emission reduction.. 

Table 3. Estimated Costs of Control - Devon Energy
 

Blaine County #1 Compressor Station
 

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 

compressor engine 

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 of 0.15 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
 

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Table 4. Estimated Costs of Control - Devon Energy 

Blaine County #1 Compressor Station 

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 

Unit 2 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 using the estimated annual cost and the potential controlled emissions. 

Factor 2 - Time Necessary for Compliance 

The Institute of Clean Air Companies (ICAC) has estimated that approximately 6 months 

is required to design, fabricate, and install NSCR technology for NOx control.4 Additional time 

of up to 12 months may be required for staging the installation process if multiple engines are to 

be controlled at a single facility. Based on these figures, the total time required to achieve 

emission reductions for an engine is estimated to be a total of 112 years for NOx strategies. 

Factor 3 - Energy and Non-Air Impacts 

Installation ofNSCR on the 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 accept the return of spent catalyst material, where they are regenerated 

on-site and used again. 5 

4 Institute of Clean Air Companies (2006), Typical Installation Timelines for NOx Emissions Control Technologies
 

on Industrial Sources.
 

5 Letter and attachments from Smith, J. C., Institute of Clean Air Companies, to Neuffer, W. J., EPA/ISB. May 14,
 

1992. Use of catalyst systems with stationary combustion sources.
 

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Factor 4 - Remaining Equipment Life 

The rich-bum engines were noted by the facility to have an expected equipment life of 5 

to 25 years from present. Therefore, it was assumed for this analysis that the engines will not be 

retired prior to the amortization period (20 years) for the specific control equipment. 

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