# C ASE 

# S TUDIES OF 

# S TATIONARY



# R ECIPROCATING 

# D IESEL 

# E NGINE



# R ETROFIT 

# P ROJECTS

August 2007

Manufacturers of Emission Controls Association

1730 M Street, NW * Suite 206 * Washington, DC 20036

www.meca.org www.dieselretrofit.org1 Table of Contents

1.0 Introduction.............................................................................................................. ... 1

2.0 Stationary Diesel Engine Case Studies...................................................................... 3 2.1 Demonstration of Emission Cont rol Technologies on Diesel-Fueled Backup Generators ....................................................................................................... 3 2.2 The Simultaneous Reduction of NOx, PM, HC and Co from Large Stationary Diesel Engines Usi ng SCR and Particulate Filters .................................... 5 2.3 Kings County, CA, Department of Public Works................................................... 7 2.4 National Steel and Shipbulding Company (NASSCO)........................................... 8 2.5 Pacific Bell-SBC Tel ecommunications Facility..................................................... 8 2.6 Santa Clara County Building Operations.............................................................. 9 2.7 Sierra Nevada Brewing Company, Chico, CA..................................................... 10 2.8 Memorial Hospital of Los Banos, Los Banos, CA ............................................... 10 2.9 Fresno Regional Medical Center, Fresno, CA .................................................... 11 2.10 New Jersey Department of Envir onmental Protection Stationary Diesel Particulate Filter Project............................................................................................ 11 2.11 Intel Corporation, San Jose, CA........................................................................ 11 2.12 Demonstration of a NOx Control Sy stem for Stationary Diesel Engines .......... 11 2.13 Evaluation of NH3-SCR Catalyst Technology on a Stationary Diesel

Genset ......................................................................................................................... 13 2.14 Additional SCR Projects .................................................................................... 13

3.0 Summary.................................................................................................................... 142 1.0 Introduction

Diesel engines provide im portant fuel economy and durability advantages for stationary diesel reciprocating engines. Although they are ofte n the power plant of choice for stationary applications, they have the disadvantage of emitting significant amounts of particulate matter (PM) and oxide s of nitrogen (NOx), and lesser amounts of hydrocarbon (HC), carbon monoxide (CO) , and toxic air pollutants.

Stationary diesel engines are significant contributors to air pollution in many

cities in the U.S. It is estimated that there are some 600,000 existi ng stationary diesel engines that are in use nationw ide, with electrical generato rs accounting for more than half of the total. The populat ion of stationary diesel engine is expected to continue to grow. In efforts to address air pollution from stationary di esel engines, the U.S. EPA issued its final requirements to reduce emi ssions of air pollutants from stationary CI engines on June 28, 2006. The final standa rds, known as New Source Performance Standards (NSPS), limit emissions of nitroge n oxides (NOx), particulate matter (PM), sulfur dioxide (SO2), carbon monoxide, (C O), and hydrocarbons (HC) from stationary diesel engines to the same stringent levels required by EPA’s Tier 4 nonroad diesel engine regulations (see http://www.epa.gov/ttn/caaa/ t3/fact_sheets/ci_nsps_fnl_fs.html#moreinfo ).

In addition, as part of the Diesel Risk Reduction Plan, California Air Resources Board adopted the Airborne Toxic Control Measure (ATCM) for St ationary Compression Ignition Engines on September 9, 2005. Statio nary diesel engines emit approximately 950 tons per year of diesel PM in California and the goal of this re gulation is to reduce diesel PM and criteria pollutant emissions from stationary diesel engines through stringent emission limits and operational requirements (see http://www.arb.ca.gov/d iesel/statport.htm ). In order to ensure that a particular emission control technology achieves certain level of PM emissions reduction, ARB created a technology verification program. Currentl y, ARB has six PM retrofit technologies verified for stationary diesel engine applications. Majority of the verified technologies are diesel particulate filters (DPFs), with one system incorporating DPF with an exhaust gas recirculation (EGR) system, achieving PM reduction of 85 percent and greater. The EGR and DPF technology is also verified for 50 percent NOx reduction. ARB list of verified retrofit technologies for stat ionary diesel engines can be found at: http://www.arb.ca.gov/diese l/verdev/vt/stationary.htm

.

The case studies discussed in this paper focus on those projects that have been completed, or are in progress for retrofitting stationary diesel engines with emission controls technologies such as diesel oxidati on catalysts (DOCs) and DPFs for controlling diesel PM emissions, and selective catalytic reduction (SCR) catal ysts for controlling NOx emissions. Many of the projects highlight the feasibility of in stalling verified onroad technologies on stationary diesel engines and relate some of the lessons learned that may assist others in planning additional st ationary projects. This paper focuses on technology based strategies and where available, provides info rmation on specific type of technology installed on the type of stationary diesel engines, and the emission reduction3 that was achieved. More basic informa tion on available emission control retrofit technologies is available in MECA’s whitepaper, Retrofitting Emissions Controls on

Diesel-Powered Vehicle ( www.dieselretrofit.org ).

2.0 Stationary Reciprocating Engine Diesel Retrofit Case Studies:

2.1 Demonstration of Emission Control Technologies on Diesel-Fueled Backup

Generators

The University of California, Riversid e (UCR) Bourns College of Engineering –

Center for Environmental Research and Technol ogy (CE-CERT), as part of the California Public Interest Energy Research (PIER) Progr am, conducted research to measure criteria

and toxic emissions from a number of uncontrolled dies el-fueled backup generators (BUGs) that were representative of those us ed in California. The project was later expanded to incorporate a demonstration pr ogram of emission c ontrol technology. The objectives of this portion of the research we re to assess applicable environmental control technologies and conduct field tests of BUGs units and control alternatives.

During the demonstration project, eight PM control technologies were demonstrated, including fuel modificati on, addition of emissions control retrofit technology and combination of both. The dur ability time of the technology was set to

167 hours to allow the control t echnology participants to obta in a conditional verification with ARB. The ARB, the Energy Commi ssion, and UCR chose the emission control devices based on key elements: the technol ogy’s state of commercialization; the willingness of the vendor to supply the technology at no cost; and the need for that technology type in the demonstration matri x. The following devices were chosen:

• Water emulsified fuel (2 0% water emulsification)

• Diesel oxidation catalyst (DOC)

• Active diesel particulate filter (DPF) with online filter regeneration by electrical heating

• Catalyzed DPF (passive DPF)

• DOC with fuel-borne catalyst

• Fuel-borne catalyst with DPF

The engine models that were selected for testing were: 1985 De troit Diesel (DDC) V92 two-stroke diesel engine installed in a 300 kW generator a nd 2000 Caterpillar 3406 C four-stroke diesel engine in stalled in a 350 kW generator.

Emulsified Fuel

The emulsified fuel consisted of a blend of water, conventional diesel fuel, and a mixture of special compounds that was adde d to the fuel to maintain the emulsion, enhance cetane number and lubricity, inhibi t corrosion, and protect against freezing. The formulated fuel contained 77 percent diesel fuel, 20 percent water, and 3 percent additive package. This fuel might not be of interest for applications like emergency generators,4 because the fuel needs to be circulated in order to prevent the suspension from breaking down into hydrocarbon and water phases. CE-C ERT tested the emulsified fuel in two engines, first a modern and post-control (a fter 1996) unit and se cond, a unit from 1986

from the same manufacturer. The fuel test ed on the modern BUG showed reductions for all load points and an overal l reduction in the emission factors of 69 percent and 13 percent for PM and NOx, respectively. Test with the second BUG, a 1986 CAT 3406B,

showed less of a reduction in both PM and NOx with the overall re duction of 25 percent PM and 4 percent NOx. Because PM reduction is linked to a reduction in the diesel oil droplet size in the cylinder and to the in jection pressure, CE-CERT believes that the much lower injector pressure used on this unit did not provide the same capability of reducing droplet size, leading to the reduce effectiveness in reducing PM and NOx.

Diesel Oxidation Catalyst

Two DOCs, DOC-1 and DOC-2, were inst alled on a modern CAT 3406C engine. DOCs are not expected to be very effectiv e in reducing the solid or elemental carbon portion of the diesel exhaust associated with PM. Therefore, the overall reduction effectiveness of DOCs depends on the proportion of the PM that is volatile. For DOC-1, PM was reduced by 25 percent and NOx was increased by 6 percent. For DOC-2, PM was reduced by 6 percent and showed no change in NOx.

Passive Diesel Particulate Filter

The passive DPF system used during this demonstration comprised of a proprietary platinum-based oxidation catalyst installed upstream of a wall-flow particulate filter typical ly made of cordierite. The plat inum catalyst oxidizes a proportion

of the NO in the exhaust stream to form NO 2 and this NO 2 is used to combust the soot trapped in the DPF. Two passive DPFs (DPF-1 and DPF-2) were retrofitted on a MY2000 Caterpillar 3406C diesel ge nerator. Initial emission te sting of DPF-1 resulted in control efficiencies for PM of just below 85 percent, which is lower than expected. When the device was opened, black streaks were noted on the white filter, indicating that a leak around the ceramic monolithic filter and housing had occurred. The DPF-1 was repaired. The control efficiency of D PF-2 was measured at 91 percent for PM, 98 percent for non-methane hydrocarbon (NMHC), and 76 percent for CO. Total NOx for DPF-2 decreased about 9 percent from the uncontrolled BUG’s emissions.

Active Diesel Particulate Filter

The active DPF system comprised of three silicon carbide diesel particulate filters with an electrical regeneration system designe d to provide continuous PM control. The triple filter system provides uninterrupt ed emission filtration during regeneration by switching the exhaust flow be tween filters. The components of the system are the ceramic wall-flow filter elements, electronic co ntrol unit (ECU), electrical heater system, compressed air blower system, and valve sy stem to switch the exhaust flow between filters. Because the system operates in tw o distinct modes, soot and regeneration, emission testing was performed in triplicate for both modes. The emission test results5 show a greater than 99 percent reduction in PM for both modes. Additionally, NMHC was reduced by about 45 percent and NOx by 10 percent. Although the PM reduction was very high, this system had two areas of concern: 1) Backpressure levels measured during durability were higher than expected. The device manufacturer attributes this to differences in engine exhaust flows and e xhaust hardware between the Caterpillar 3300 and 3400 Series engines. Presumably, the issu e associated with th e higher backpressure could easily be addressed duri ng the design phase of statio nary source retrofitting. 2) During the intermittent cold start portion of dur ability cycling, the soot mode was longer than had been indicated by the manufacturer. As a result, filters were not regenerating as often as described during cold start operati on and backpressure increased. Because the regeneration system is controlled only by tim e and not backpressure sensors, this control scheme may need optimization for applic ations with multiple cold starts.

Fuel-borne Catalyst and Diesel Oxidation Catalyst

Originally, a flow-through filter system was retrofitted on a 1985 MY 2-stroke Detroit Diesel V92. This system was a passi ve, flow-through filter combined with a fuelborne catalyst to reduce PM emissions. A DOC , also part of the system, reduced CO and HC emissions. However, this system experienced regeneration problems during degreening operation. The exhaus t temperatures were not suffi cient for regeneration and the flow-through filter clogged. Therefore, the flow-through filter was removed and the DOC, combined with the fuel-borne catalyst, wa s tested. The fuel-bor ne catalyst that was used contained 4-8 ppm of cer ium and platinum in a petrol eum distillate solution. The control efficiency of the DOC and fuel-borne catalyst syst em was 38 percent for PM and 69 percent for NMHC and NOx increas ed by approximately 4.8 percent.

Fuel-borne Catalyst and Diesel Particulate Filter

The DPF used in this dem onstration is an uncatalyzed ceramic wall flow filter combined with a fuel-borne catalyst. This system was installed on a 2000 MY Caterpillar 3406C diesel generator. The system combines a ceramic monolith trap with a fuel-borne catalyst to facilitate regenera tion of the DPF. Results from the testing showed that the

fuel/emission control device combination reduc ed PM by more than 99 percent for both

the initial test and after the durability testing.

More information on this project is available at: http://www.energy.ca.gov/pier/final_p roject_reports/CEC-500-2005-049.html

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2.2 The Simultaneous Reduction of NOx, PM , HC and CO from Large Stationary Diesel Engines Using SCR and Particulate Filters

In late 2003, Snow Summit Mountain Resort purchased generators to use during

the winter months to make snow. The resort is located at Big B ear Lake and since the area only gets an average of 75 inches of annual snow fall, Snow Summit actually makes6 an addition 36 to 60 inches of snow to c over the trails. Because the Snow Summit Mountain Resort comes under the jurisdic tion of the South Coast Air Quality Management District (SCAQMD), the air pe rmit for the diesel engines required the

installation of the Best Ava ilable Control Technology (BACT) to control emissions from these engines. Table 1 below shows the uncontrolled baseline emissions from the purchased diesel engine, the SCAQMD regul ated emissions level and the required percent reduction needed.

Table 1: Diesel Generator Engi ne Uncontrolled Emissions and SCAQMD Emissions Limits Emission Baseline Levels Regulati on Levels % Reduction Required NOx 8.75 g/bhp-hr 0.60 g/bhp-hr 93.2% CO 0.72 g/bhp-hr 0.60 g/bhp-hr 16.7% HC 0.20 g/bhp-hr 0.15 g/bhp-hr 25% PM 0.30 g/bhp-hr 0.045 g/bhp-hr 85%

The supplier of emissions control devi ces chose to install a combination of Selective Catalytic Reduction (SCR) for re ducing NOx and a diesel particulate filter (DPF) system on two diesel generators. The DPF that was installed on the generators are a passive continuously regenerating filter technology that incorporates platinum regenerated by the oxidization of NO to NO 2 . The NO 2 in turn combusts the soot that is collected in the DPF to regenerate the DPF. The SCR system that was installed uses a two-fluid technology of urea and compressed air.

Emissions Testing Results Table 2 and Table 3 show emissions test results from each engines.

Table 2: Test Results from Engine #1

Pollutant SCAQMD Emissions

Limit at 15% O 2 Actual

Emissions % Reduction Targeted % Reduction

Achieved

PM 10 0.045 g/bhp-hr <0.005 g/bhp-hr 85% >90% NOx 50 ppm 34.90 ppm 93.2% >94%

TNMEHC 39 ppm 0.15 g/bhp-hr 10.80 ppm 0.05 g/bhp-hr 25% >90%

NH 3 10 ppm 0.01 ppm Surpassed

Table 3: Test Results from Engine #2

Pollutant SCAQMD

Emissions Limit at

15% O 2 Actual Emissions % Reduction Targeted % Reduction

Achieved

PM 10 0.045 g/bhp-hr <0.005 g/bhp-hr 85% >90% NOx 50 ppm 44.27 ppm 93.2% >94% CO 89 ppm 3.62 ppm 16.7% >90%

TNMEHC 39 ppm 0.15 g/bhp-hr 3.18 ppm 0.02 g/bhp-hr 25% >75%

NH 3 10 ppm 0.00 ppm Surpassed7 The low PM values, combined with th e low NOx, CO, and HC emissions at the stack demonstrate that the criteria pollutants from a diesel engine can be simultaneously controlled by the DPF and SCR technologies.

More information on this project is available at: http://www.nj.gov/dep/airworkgr oups/docs/1chu.attachment5.pdf

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2.3 Kings County, CA, Depart ment of Public Works

Kings County, located in California’s San Joaquin Valley, subscribes to an interruptible power program with the local utilit y in order to save on el ectricity costs. As a program participant, the county receives a 25 percent lower rate on electricity but must disconnect from utility grid after being given 30-minute notice. If the county fails to disconnect in 30 minutes, it must pay a larg e penalty. After a period of frequent interruptions during the winter of 2000/2001, the County Council authorized the installation of a large generato r to supply backup power to mo st facilities located in the

Government Center in Hanford. A Cate rpillar 3516BB engine powers the backup generator and in order to comply with air quality regulations for diesel generators that run during voluntary power interruptions, the count y installed a DPF syst em on the engine.

Installation of the f ilter system was a collaborative effort involving the County, the system supplier, and the filter installer. The generator engine burns ultra-low sulfur

diesel fuel.

Engine emissions testing results before and after installation of the DPFs are

summarized in the table below. Emissions be fore DPF system installation were provided by Caterpillar, Inc. and represent emissions for the engine operati ng at 50 percent load, the average load the engine carries at the G overnment Center. Engine-out emissions for PM were also reduced by 25 percent as suggest ed by Caterpillar, Inc. to account for the use of cleaner burning California diesel fu el. The DPF was removed after 556 hours to inspect soot buildup, which would indicate if the DPF was regenerating properly. The inspection results revealed very clean filters , indicating that the engine was reaching and sustaining adequate temperatures to ensure regeneration.

Emissions Reduction Summary

Pollutant Emission Rate Before Control (g/bhp-hr) Emission Rater After Controls (g/bhp-hr) Percent Reduction

CO 0.84 0.084 90

HC 0.33 0.033 90

PM 0.179 a 0.027 a 85

NOx 6.51 NA b NA b

a PM emission rate reduced by 25% per Caterpillar, Inc. to account for lower PM emissions from CARB

diesel fuel

b Not applicable8 More information on this project is available at: www.nescaum.org/documents/r pt030612diselgenerators.pdf

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2.4 National Steel and Shipbuilding Company (NASSCO)

NASSCO, located on San Diego Bay, is the largest shipyard engaged in new ship

construction on the West Coast and builds co mmercial ships including oil tankers, ferries, container ships and research vessels. In 2001, NASSCO purchased a Cummins QST30- G1 diesel engine and generator to power Cr ane Number 16, a 300-ton gantry crane. In order to meet air quality requirements, the engine was equipped with a DPF to control PM and a selective catalytic reduction (SCR) unit to reduce NOx emissions. To keep the exhaust gas temperature high enough for the proper operation of DPF and SCR system exhaust gas heaters were inst alled ahead of the emission c ontrol system. NASSCO uses

California #2 diesel fuel to operate Crane Number 16.

Engine emissions before and after in stallation of emission controls are

summarized in the table below. The emissions rates for the engine be fore the installation

of emission control devices are from Cummin s, Inc. Emissions reductions are based on the performance claims of the emission c ontrol manufacturer and reflect the typical values observed in similar applications. Th e emission control installer estimates the DPF achieves an 85 percent reduction of PM and the SCR unit achieves a 90 percent reduction

of NOx. Source tests were conducted on th e crane by World Environmental, Inc. on March 14, 2002 and preliminary source test data confirm the SCR system achieves a

>90% reduction in NOx.

Emissions Reduction Summary

Pollutant Emission Rate Before Controls (g/bhp-hr) Emission Rate After Controls (g/bhp-hr) Percent

Reduction

CO 0.2 0.85 85

HC 1.1 0.10 85

PM 0.03 a 0.045 a 85

NOx 8.1 b 0.69 b 93
a PM emission rates reduced 25% per Caterpillar, Inc. to account for lower PM emissions from California

diesel fuel. B Nox emission rates reduced 7% per Caterpillar, Inc. to account for lower Nox emissions from California

diesel fuel.

More information on this project is available at: www.nescaum.org/documents/r pt030612diselgenerators.pdf

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2.5 Pacific Bell-SBC Telecommunications Facility

In 1994, the Pacific Bell-SBC installed tw o emergency generators at their highrise telecommunications facility in San Fran cisco, CA. To accommodate growth, Pacific Bell replaced a turbine with two Caterpillar 351 6 engines and their associated generators.9 In order to mitigate complaints of smoke a nd odors, Pacific Bell installed DPF systems on the engines. The installed filter system s are capable of reducing PM emissions by 85% and carbon monoxide and hydrocarbon emissi ons by 90%. The engine uses regular

#2 diesel fuel. Expected engine emissions before an d after installation of the DPFs are

summarized in table below.

Emissions Reduction Summary

Pollutant Emission Rate Before Controls (g/bhp-hr) Emission Rate After Controls (g/bhp-hr) Percent Reduction

CO 1.17 0.12 90

HC 0.50 0.05 90

PM 0.239 0.036 85

NOx 17.04 NA NA

More information on this project is available at: www.nescaum.org/documents/r pt030612diselgenerators.pdf

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2.6 Santa Clara County Building Operations

Santa Clara County operates a back-up gene rator in San Jose, CA. The generator provides emergency back-up power to thr ee buildings. In 1998, Santa Clara County purchased the Cummins KTTA50-G2 diesel e ngine and generator to provide emergency power for the County Service Center. To a void complaints of smoke and odors, Santa Clara County installed two catalyzed DPFs on the engine exhaust system. The engine

uses CARB diesel fuel #2.

Expected engine emissions before and after installation of the filter system on the engine are summarized in the table belo w. Emissions reductions are based on preliminary source test results provided by the emission control manufacturer for a similar emission control system in stalled at another facility.

Emissions Reduction Summary

Pollutant Emission Rate Before Controls (g/bhr-hr) Emission Rate After Controls (g/bhp-hr) Percent Reduction

CO 2.17 0.22 90

HC 0.14 0.01 90

PM 0.083 a 0.012 a 85

NOx 12.8 NA NA

a PM emission rate reduced 25% per Caterpillar, Inc. to account for lower PM emissions from CARB

diesel fuel.

More information on this project is available at: www.nescaum.org/documents/r pt030612diselgenerators.pdf

.10 2.7 Sierra Nevada Brewing Company, Chico, CA

Sierra Nevada Brewing Co mpany (SNBC) purchased two 750 kW generators to provide emergency back-up power for br ewery operations in 1997 and 1999. Both generators are powered by Caterpillar 3412 di esel engines. To meet air quality requirements, SNBC installed DPFs on the engines in 1999 and 2000. Two catalyzed DPFs were installed in parallel on each engine . The engines operate on CARB diesel fuel.

Engine emissions before and after instal lation of the DPFs are summarized in the

table below. Emissions before installa tion of the filter system were provided by Caterpillar, Inc. and are emissions for the engine operating at 75% load. SNBC typically operates their engines at a bout 80% load, but the emissi ons data at 80% were not available from Caterpillar, Inc. As sugge sted by Caterpillar, Inc., uncontrolled engine

emissions from NOx and PM were reduced by 7% and 25%, respectively, to account for the use of cleaner burning CARB diesel fuel. ARB performed source tests on SNBC’s engines on March 20-24, 2000.

Emission Reduction Summary

Pollutant Emission Rate

Before Controls (g/bhp-hr) Emission Rate

After Controls (g/bhp-hr) Percent Reduction

CO 0.84 0.084 90

HC 0.33 0.033 90

PM 0.164 a 0.025 a 85

NOx 6.69 b 5.85 12

a PM emission rate reduced 25% per Caterpillar, In c. to account for lower PM emissions from CARB

diesel fuel.

b NOx emission rate reduced 7% per Caterpillar, Inc. to account for lower NOx emissions from CARB

diesel fuel.

More information on this project is available at: www.nescaum.org/documents/r pt030612diselgenerators.pdf

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2.8 Memorial Hospital of Los Banos, Los Banos, CA

The Memorial Hospital of Los Banos installed a DPF on a 1994 Caterpillar 3406, 519 horsepower engine operating an emerge ncy backup generator. The DPF was installed in 2002 to comply w ith the San Joaquin Valley Ai r Pollution Control District emission permit requirements. The hospital ru ns the engine about 30 minutes per week for maintenance and testing a nd the exhaust temperature is monitored during the weekly engine test.11 2.9 Fresno Regional Medical Center, Fresno, CA

Fresno Regional Medical Center inst alled a catalyzed DPFs on five 2002 Caterpillar 3516TA, 2680 horsepower engines that power Caterpillar SR4 B emergency backup generators. As part of the San Jo aquin Valley Air Pollution Control District permit, the medical center was required to reduce PM emissions. Emission information provided to the medical center stated that a Caterpillar generator produce 0.10 g/bhp-hr of

PM without an emission control device. The Caterpillar generator running on CARB

diesel and a DPF has PM emi ssions reported at 0.01 g/bhp-hr.

2.10 New Jersey Department of Environmen tal Protection Stationary Diesel Particulate Filter Project

The New Jersey Department of Environmental Protection (NJDEP), in

collaboration with the Stevens Institut e of Technology and an emissions control technology manufacturer, initiated a project to install diesel particulate filt ers on five 500 kW electric diesel generators located at the Jersey City Total Energy Plant. This energy plant is a co-generation facili ty that supplies heat and air conditioning. These generators were retrofitted with catalyti c diesel particulate filters th at continuously regenerate at normal operating temperatures. The DPF is expected to reduce combined PM, CO and HC emissions by at least 85 percent. NJ DEP will demonstrate the DPF for six months and develop an inventory of di esel engines in New Jersey with the associated yearly

emission estimates. NJDEP will also determine the applicability of DPFs with respect to the New Jersey Inventory of stationary sour ces in reducing stationa ry diesel emissions.

2.11 Intel Corporation, San Jose, CA

Intel Corporation installed two DP Fs on a Caterpillar 3412C, 896 horsepower engine that powers an emergenc y backup generator. The faci lities manager stated that they have not had any problems with the D PF and there is no extra maintenance.

2.12 Demonstration of a NOx Control Sy stem for Stationary Diesel Engines

The Electric Power Research Institute (EPRI), the California Energy Commission (CEC), and Hawaiian Electric Company (HECO) have partnered to further develop an emerging emission control technology for retrof itting stationary dies el engines. They

identified an emissions control device manu facturer having unique technical capabilities and a novel design for a cost effective, rege nerative lean NOx trap system capable of greater than 90 percent reduc tion and an integrated dies el particulate filter.

The manufacturer developed a system whic h consisted of a fuel processor with a third-party, commercial lean NOx adsorber trap that will achieve greater than 90 percent NOx reduction. The fuel processor converts dies el fuel to reactive reductants, such as H 212 and CO to rapidly and complete ly regenerate the NOx trap. These reductants convert the trapped NOx to N 2 . This system was demonstrated on a 8.3 liter, 160 kW, Cummins stationary generator set. The demonstration project is planned in three phases: the Technology Demonstration (Phase I), Field Demonstration (Phase II), and Pilot Production (Phase III). The goal of Phas e I is to demonstrate a NOx reduction technology on a 160 kW diesel-fuele d reciprocating engine that can be scaled up to a size range of 250 to 2,000 kW in Phase II. The meas urable objective is to achieve 90 percent NOx removal using the selected emission c ontrol technology for 100 hours of base-load operation and to measure the fuel penalty a ssociated with achieving the 90 percent NOx reduction. The Phase I Technology Demonstrat ion was completed in December 2004. In Phase II, an ARB-verified, regenerative diesel particulate filter will be integrated into the system design (consisting of an Emissions Syst em Control Unit (ESCU) , a throttle valve, the fuel processor, and lean NOx trap (LNT)) and two units will be developed and installed on two diesel engines for field demons tration testing. The goa l of this phase is to achieve 95 percent NOx reduction. Phas e II consists of pre-commercial, limited release operation at multiple commercial sites.

Phase I Technology Demonstration:

Task 1: The manufacturer retrofit ted the Cummins 8.3 liter, 160 kW generator set with a throttle valve and control system to enable automatic control of the fuel/air mixture.

Task 2: The emissions control device hardware wa s designed and fabricated. Several fuel processor catalyst materials were evalua ted and the most suitable were selected.

Task 3: Several NOx traps were evaluated for their suitability in the system.

Task 4: Demonstrate the feasibility of a greater than 90 percent NOx reduction system for 100 hours on a stationary 160 kW diesel gene rator set. The measured average fuel penalty for the entire test was approximately 7 percent, but this fuel penalty was not optimized.

During Phase I, the cumulative NOx c onversion averaged over the entire 100- hour test was 92 percent. During the first 20 hours of the test, average NOx conversion dropped below 90 percent several times while the control system was being tuned and refined. After fine-tuning the control sy stem, NOx conversion remained between 90 percent and 94 percent with the cumulative time weighted average NOx conversion increasing with time after the first 20 hours. The manufacturer disc overed that the actual capacity of the full-scale LNTs was signifi cantly less than predicted, based on the subscale LNT test results. The LNT vendor sugge sted that the capacity difference was due to their prototype production process depos iting a non-uniform washcoat loading on the full-scale traps. The vendor explained that this performance shortfall would not be expected from commercially manufactured tr aps. The NOx trapping capacity shortfall resulted in the inability of the prototype hardware to maintain 90 percent NOx reduction for an extended period of time. As a result, a fourth trap had to be added to the system to meet the performance objectives of the 100-hour test.

The next phase of the project, Phase II de velopment and field trials, will include:

• Integrating the LNT system with an A RB-certified diesel particulate filter and produce two integrated units for field tria ls with design goals of 95 percent NOx13 and 85 percent diesel particulate matter (PM) removal at minimal fuel penalty. One unit will be sized for a 500 kW engine and the second for a 1,000 kW engine.

• Installing these two units on existing diesel engines at two different locations and operated for 1,000 hours each under normal operating conditions.

At the conclusion of Phase II field demonstr ation, the results will be analyzed and a decision will be made as to whether to proc eed with Phase III, where this NOx control technology will be made available to the ge neral public on a limited release basis while the pilot manufacturing details are worked out and preparations are made for a full commercial release. More information on this project is available at: http://www.energy.ca.gov/pier/final_p roject_reports/CEC-500-2005-129.html

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2.13 Evaluation of NH 3 -SCR Catalyst Technology on a Stationary Diesel Genset

Three technology manufacturers and U. S. Navy, Naval Surface Warfare Center collaborated together to dem onstrate “proof-of-concept” of ammonia-selective catalytic reduction (SCR) and diesel oxidation catalyst system on a 250 kW diesel genset. The SCR and DOC were installed on a Caterpillar 3306 diesel generator set engine, rated at 1800 rpm, 250 kW. The catalyst system wa s a four bank system, each bank with two 5 liter SCRs and one 2.5 liter DOC brick. The emissions testing for the system was conducted by a third party, GE Energy Manage ment Services. During the field testing, the engine was maintained at 90 percent lo ad, using U.S. #2 diesel fuel. Data was

collected at different w eather conditions by running the engine for 500 hours at 90 percent load. Exhaust gas analysis (NO, NO 2 , CO, CO 2 , and O 2 ) was conducted upstream and downstream of the catalytic converter. Secondar y emissions of NH 3 , CO, VOCs, and PM were verified by the third part y GE Management Services. Results from the emissions testing showed 70 to 80 percent conversion of NOx to N 2 at 90 percent load

and NH 3 /NOx of about 0.8.

More information on this project is available at: http://www1.eere.energy.gov/vehiclesandfue ls/pdfs/deer_2005/poster2/2005_deer_malya la.pdf

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2.14 Additional SCR projects:

There have also been several projects involving installation of SCR systems on stationary, natural gas fired, reciprocating en gines to comply with NOx regulations. For more information on these projects, go to: http://www.icac.com/i4a/pages/ index.cfm?pageid=3356#Multi-p

.14 3.0 Summary

As shown by the above case stud ies, experiences with retrof itting stationary diesel engines with emission control devices are grow ing. These stationary engine case studies are another example of the succe ssful transfer of diesel retr ofit technology originally developed for reducing diesel particulate a nd/or NOx emissions from on-road diesel engines into off-road diesel engine applica tions. The availability of ultra-low sulfur diesel (ULSD) fuel for non-road diesel e ngines will expand significantly now that the national rollout of ULSD for highway appli cations has been completed. This should facilitate even wider application of retrofit filt er technologies on statio nary diesel engines. Areas of the country with severe ozone probl ems are also prime targets for EGR or SCR retrofits on stationary engines for reduci ng NOx emissions from these sources. The examples cited in this report provide firm evidence that retrofit technologies can be a successful, cost-effective strategy for reducing emissions from stat ionary diesel engines.