Air Quality Testing of Biodiesel

8/6/2019 Air Quality Testing of Biodiesel

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FINAL REPORT

to the

Legislative Commission on Minnesota Resources

Improving Air Quality by Using Biodiesel inGenerators

Submitted by:

Kenneth L. Bickel University of Minnesota


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LIST OF TABLES

1 - Engine speed and load modes. 10

2 - Effects of Performance Gold Plus (D2+) and 20% biodiesel blends with EHN

on NOx emissions ....13

3 - Effect of Performance Gold (D2) and biodiesel blends on NOx emissions .14

4 - Effect of EHN on B20 NOx emissions.15

5 - Effects of Performance Gold (D2) and biodiesel blends with EHN on

NOx emissions..16

6 - BSFC using Performance Gold (D2), B20 and B8518

7 - Energy content of Performance Gold (D2), B20, and B85 fuels.18

8 - Brake specific NOx and PM emissions for Performance Gold (D2) fuel

as a function of charge air temperature.19

9 - Effect of Performance Gold (D2) and B20 on NOx and PM Emissions ....19

10 - Effect of Performance Gold (D2) and B20 with DOC on NOxand PM Emissions20

11 - Effect of Performance Gold (D2) and B85 on NOx and PM

Emissions..21

12 - Effect of Performance Gold (D2) and B85 with DOC on NOxand PM Emissions.21

13 - Effect of Performance Gold (D2) and Performance Gold Plus (D2+) on NOx

and PM Emissions.22

14 - Comparison of NOx, CO, and Total PM emissions for D2 and B20 at identicalengine loads and intake charge air temperatures..26

15 - Comparison of NOx, CO, and Total PM emissions of D2 at two engine loads


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LIST OF FIGURES

1 Air-to-air aftercooler diagram with typical temperatures and pressures...8

2 Jacket-water aftercooler diagram with typical temperatures and pressures...9

3- Gaseous and particulate emission sampling train used during field

demonstration.25

4 - Demonstration site ...25

5 - Emissions sampling on site ..26


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Improving Air Quality by Using Biodiesel in Generators

EXECUTIVE SUMMARY

A biodiesel / petroleum fuel blend and practical low-cost methods of emission control were

sought to obtain reductions in oxides of nitrogen (NOx) and particulate matter (PM)

emissions from diesel generators. Secondary consideration was given to carbon monoxide(CO) and hydrocarbon (HC) emissions reductions. The project had three parts: (1) Reviewof Existing Technology; (2) Laboratory Evaluation of Biodiesel and Emission Controls, and

(3) Demonstration on a Peak Shaving Generator.

Little direct testing of biodiesel in diesel-powered electric generators (gensets) has beendone. Building on existing research on biodiesel fuels, the University of Minnesotas

Center for Diesel Research (CDR) evaluated soy-based biodiesel fuels for reducing

exhaust emissions in gensets. After determining the types of engines used for standbyand peak shaving applications in Minnesota, and selecting blend levels and applicable

emission controls for use with those engines, a laboratory evaluation was conducted todetermine the influence of using biodiesel on diesel exhaust emissions from generators.

Neat biodiesel was blended with regular and premium commercial low-sulfur petroleum

diesel fuel. B20 (20% biodiesel / 80% petroleum diesel) was chosen because of

previously successful studies with this blend level, and because there is evidence that theNOx emissions increase that results from using B20 can be controlled using existing

technology. B85 was selected because: 1) it is a high blend, which promised to give a

large decrease in PM at the expense of a larger increase in NOx than B20, and 2) theMinnesota House of Representatives was considering legislation to provide financial

incentives for new generator facilities using B85. That legislation was not subsequently

adopted.

Two primary NOx control techniques were evaluated during the laboratory tests, charge-

air cooling and a cetane number improving fuel additive. For PM, CO, and HCreduction, a diesel oxidation catalyst (DOC) was evaluated. A 276 kW Cummins model

ISM was selected to be the laboratory test engine because it is used in some models ofCummins-powered electric generators and it was available for tests at CDR.

Initially, screening tests using a NOx-reducing fuel additive and biodiesel blends were

conducted to determine if the fuel additive could offset the increase in NO x emissions that

normally occurs using biodiesel. The fuel additive was not effective at reducing NOx in


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Based on the results of the laboratory testing, CDR proceeded to evaluate B20 and themost practical emission control (charge air-cooling) on a generator at the School of

Environmental Studies in Apple Valley, MN. The demonstration genset engine was aCaterpillar model 3406 B, turbocharged and jacket-water aftercooled engine. Thegenerator was rated 400 kW standby and 365 kW prime at 60 Hz, 1800 rpm.

A separate supplemental cooling circuit for the engine intake air was designed andinstalled that contained a separate shell & tube heat exchanger cooled with city water.

This cooling circuit enabled a 40 degree C reduction in the temperature of the intake air

charge to the engine to be attained, which closely duplicated laboratory test conditions.

A comparison of NOx, CO, and PM emissions for D2 at 90o C charge-air temperature and

B20 at 50 degrees C charge-air temperature demonstrates the emissions reduction that

may be achieved by switching from D2 with normal charge-air temperature to B20 withsupplemental charge air-cooling. Under this scenario, average NOx emissions are

reduced 15-18 percent. The NOx reductions seen in the field test matched those from the

lab tests very well. PM was reduced 39 to 47 percent. However, the PM reductions seenduring the field tests were significantly higher than those seen in the lab. The dilution

system used during the field sampling may have biased the PM emission results. Thecommercial system used for the lab tests is designed to minimize any sampling losses.

The field dilution apparatus may have had sampling line losses due to condensation ofvolatile material or thermophoretic deposition of PM. The lab results, where reductions of

up to 18% were measured while using B20, are closer to the expected PM reductions

associated with operating an engine on B20.

The laboratory and field tests demonstrated that a renewable fuel, such as B20, whencombined with supplemental cooling of the intake air, can be used in gensets to achieve

significant reductions in NOx and PM.


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ACKNOWLEDGEMENTS

The Improving Air Quality by Using Biodiesel in Generators project was funded inpart by the 2001 Legislature as recommended by the Legislative Commission onMinnesota Resources. Funding is from the Environment and Natural Resources Trust

Fund.

The University of Minnesota Center for Diesel Research thanks the Legislative

Commission for Minnesota Resources for their sponsorship of this collaborative project.

The full scope of this project could not have been realized without the participation of the

following organizations:

Agricultural Utilization Research Institute provided fuel analyses,technical support, and research funds.

Dakota Electric Association provided research funds. East Central Energy provided research funds. Energy Alternatives provided the field demonstration genset and technical liaison.

Ethyl Corporation provided the EHN fuel additive and some fuel analysis. Great River Energy provided research funds. Minnesota Department of Commerce provided research funds. Minnesota Soybean Research & Promotion Council provided research funds. School of Environmental Studies at the Minnesota Zoo in Apple Valley.

(Independent School District #196) provided access to the genset on school

property and logistical support.

A special thanks goes to Mr. Phil Kairis of Energy Alternatives for his initiative to obtainfinancial support from several energy providers and for coordinating technical support forthe field demonstration.


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INTRODUCTION

Biodiesel fuel is a renewable, biodegradable, mono alkyl ester combustible liquid fuelderived from agricultural plant oils or animal fats, that meets American Society forTesting and Materials Specification D6751-02 Biodiesel Fuel (B100) Blend Stock for

Distillate Fuels. In its neat form, biodiesel contains little or no sulfur or polynuclear

aromatic hydrocarbons, has a high cetane number, and is biodegradable. The potentialproduction of biodiesel is from 2 to 6 billion gallons per year in the United States.

When burned in a diesel engine, biodiesel reduces PM, CO, and HC emissions. The

nature of the PM emissions also changes. When compared to petroleum fuel, biodiesel-fueled engines produce PM with a higher volatile organic fraction and lower nonvolatile

organic or carbon fraction. However, biodiesel also tends to increase emissions of NOx.

The change in emissions is related to the amount of biodiesel in the biodiesel blend.

Most engine and fuel injection equipment manufacturers believe that use of up to 5%

blends of biodiesel in petroleum diesel will have no adverse effects and can result in asignificant improvement in fuel lubricity. There is little change in polluting exhaust

emissions at this level. The biodiesel industry supports the use of 20% blends, whichresults in a significant reduction in PM emissions relative to conventional diesel fuel.

There are some technical issues remaining concerning the use of higher blend levels.These include the potential for poor oxidative stability, incompatibility with fuel system

elastomers, low-temperature flow properties, and increased oxides of nitrogen (NOx)

emissions. However, numerous studies have shown that modern diesel engines requireno modifications and have no problems using B20 biodiesel fuel.

Little direct testing of biodiesel in diesel-powered electric generators (gensets) has been

done. Building on existing research on biodiesel fuels, the University of Minnesotas

Center for Diesel Research (CDR) evaluated soy-based biodiesel fuels for reducingexhaust emissions in gensets. The project had three parts: (1) Review of Existing

Technology; (2) Laboratory Evaluation of Biodiesel and Emission Controls, and (3)

Demonstration on a Peak Shaving Generator.

A biodiesel / petroleum fuel blend and practical low-cost methods of emission control weresought to obtain reductions in NOx and PM emissions. Secondary consideration was given

to CO and HC emissions reductions. After determining the types of engines used for peakshaving in Minnesota, and selecting blend levels and emissions controls for use with

those engines, a laboratory evaluation was conducted to determine the influence of using

biodiesel on diesel exhaust emissions. Several fuel blends and emission control


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REVIEW OF EXISTING TECHNOLOGY

A significant effort was made to obtain data on the numbers and types of gensets that areused in MN. Files for air quality permit applications to the MN Pollution ControlAgency were reviewed for data on generators used in the 11-county metro area. The

University of MN provided data on gensets used for standby and peak shaving, their size,

fuel consumption, and use. A generation and transmission utility and rural cooperativeprovided information on the number of peak shavers they have under contract. An

engineering firm that designs and builds peak shaving generator facilities also supplied

data. This information was used for selecting an engine and emission control

technologies to be evaluated during the laboratory evaluation and field demonstration.

Methods for reducing PM and NOx emissions were compiled from technical literature

and personal communications. The methods included cooling of the charge-air (airdrawn into the engine for combustion), fuel additives, exhaust aftertreatment, and others

such as exhaust gas recirculation. Based on this review, practical, low cost methods of

reducing emissions were selected for evaluation during the laboratory testing. Themethods selected were a NOx-reducing fuel additive, charge-air cooling, and a diesel

oxidation catalyst (DOC).

Generator Data

The Center for Diesel Research (CDR) obtained data on generators used in MN from the

following organizations:

Minnesota Pollution Control Agency - The PCA began permitting large facilities in the1970s, and smaller facilities in the 1980s. PCA does not require a permit simply for

having a generator. However, since 1993, PCA has required that anyone obtaining an air

quality permit that has a generator that is 100 kW or larger include it in the permitapplication. They are now considering requiring permits for any facility having a

generator over 500 kW in size. They provided the CDR with a list of permitted facilities

that reported burning diesel fuel in an engine on their permit application. CDR reviewedthe permit application for each facility for data on generator(s) that facility had listed in

the permit. The amount of generator information contained in the permit applicationsvaried greatly. Some permits listed detailed information, while some only mentioned

having a generator at the facility. CDR found permit application files for 156 facilities inthe 11-county metro area that listed at least one generator in the application. The data

was entered into Excel files for sorting and analysis.


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d) The generator rating was listed for 143 units, ranging from 18-2400 kilowatts(kW), with an average of 817 kW.

e) 145 permits identified the date of the installation. The average date of installationwas 1987.

f) The engine make was identified for 169 units. 54 were Caterpillar units,Cummins made 82, and the remaining 33 units were made by 8 different

manufacturers.

University of Minnesota - CDR obtained data on all of the 88 generators installed at the

University of Minnesotas Minneapolis and St. Paul campuses. The data included

information on generator make and model, generating capacity, installation date, fuelstorage, and other data. Although the data is incomplete, the predominant genset

manufacturers were Onan and Kohler and Cummins and Caterpillar were the

predominant engines. The Cummins gensets supply electrical power in the range of 75 to775 kW, with an average power of 248 kW. The Caterpillar generators supply power in

the range of 250 to 2000 kW with an average of 726 kW.

Others A generation and transmission utility serving rural cooperatives throughout the

state provided proprietary information on the number of commercial and interruptiblecustomers for each of the cooperatives they service. A rural cooperative, supplying

power to customers in nine counties, provided propriety data on engine make, model,generating capacity and age for generators in their service area. The proprietary

information from the utility companies will only be briefly summarized here. The units

were installed from 1994-2001, and ranged in size from 60-1190 kW. Caterpillar mademost of the units, although many rated at 400 kW or less were made by other

manufacturers. Most of the peak-shaving units were larger than 400 kW, and hadturbocharged and after-cooled engines.

Ziegler, Inc. is one of the largest suppliers of engines and construction equipment inMinnesota. They supplied CDR with propriety data on the engine make, model,

generating capacity and age for 108 commercial generators in the metro area. All the

generators used Caterpillar or Caterpillar-Perkins engines.

Appendix A contains data from the diesel generator survey.

Conclusions from the generator data - CDR was unable to obtain a figure for the numberof standby or peak-shaving generators in the metro area, or for any part of Minnesota.

While the data from the PCAs air quality permits gave perhaps the best sample of the

generators used in the metro area, the information given on the permits was often


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The genset data was used to help select the engine, type of emission controls, and theengine test cycle to evaluate in the laboratory. The engine selected was a University-

owned 386 horsepower, turbocharged, aftercooled engine used in some models ofCummins-powered electric generators.

Methods of Controlling Emissions

Methods of controlling emissions were compiled from technical literature and personal

communications. Summaries of emissions control technologies are given in Appendices

B-D. Appendix B is a summary of NOx control technologies with their pros and cons and

Appendix C is a description of commercial NOx and PM controls and their principles ofoperation. Appendix D is a summary of fuel modification techniques for emission control

that are potentially applicable to diesel gensets.

The three most practical emission control techniques selected to undergo laboratory

evaluation were intake charge-air cooling and fuel additives for NOx control, and a DOC for

CO, HC, and PM control.

LABORATORY EVALUATION OF BIODIESEL AND EMISSION CONTROLS

Methods and Materials

Fuels- Two diesel baseline fuels were tested: regular D2 and a premium D2 diesel fuel.The baseline engine emissions were determined using diesel fuel with no emission

control techniques. The emissions resulting from biodiesel blends and three emissioncontrol techniques were compared to baseline emissions

Two biodiesel blends were chosen that potentially could provide NOx and PM reductionswhen combined with the exhaust control technologies chosen in Part 1. B20 (20%

biodiesel / 80% petroleum diesel) was chosen because there is considerable experience

with B20 in the U.S., and there was evidence that the NOx emissions increase that resultfrom using B20 could be controlled using fuel additives. B85 was selected because it is

a high blend, which promised to give a larger decrease in PM at the expense of a largerincrease in NOx than B20, but still within the range of control with existing technology.

Also, while planning for the laboratory evaluation, the Minnesota House ofRepresentatives was considering legislation to provide financial incentives for new

generator facilities using B85. That legislation was not subsequently adopted.


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Diesel Test Engine - The test engine used during the lab evaluation was a Cummins

model M11turbocharged programmed to a 1999 ISM 370 model. The engine was anelectronically controlled, 6-cylinder, 10.8-liter, direct (unit)-injection, turbocharged andaftercooled diesel rated 370 hp (276 kW) at 1800 rpm.

Intake Charge-Air Cooling Cooling the engines intake air charge was the primary NO xcontrol technique tested. Charge air-cooling lowers the intake air temperature and lowers

peak cylinder pressure and temperature that result in lower NOx. The heart of the system

is the heat exchanger, which can be either air-to-air (Figure 1) or jacket-water (Figure 2)

aftercooled. Both air-to-air cooling and jacket-water cooling, where charge-airtemperatures are thermostatically controlled to about 90C, are used in generator

applications.


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Figure 1 Air-to-air aftercooler diagram with typical temperatures

and pressures.


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Figure 2 Jacket-water aftercooler diagram with typical temperatures

and pressures.

For the laboratory test, a shell and tube heat exchanger was used to control the intake air

temperature. Three charge-air temperatures (nominally 45o, 65o, 90C) were selected for

the test matrix. These temperatures were selected because: 1) the 90o

C intaketemperature would simulate the operation of a jacket water aftercooled engine, 2) the

intake air temperatures could be duplicated each day despite variations in the flow of

house water to the auxiliary heat exchanger, and 3) the 45o C reduction in intake air

temperature would lower NOx emissions sufficiently to offset the expected NOx increaseusing B85.

Fuel Additive

Fuel additives, known as cetane number improvers or ignition improvers,are used to raise a fuels cetane number. By increasing the cetane number of diesel fuel,

the ignition delay time (the time between injection and ignition when fuel is sprayed intothe combustion chamber) is reduced and may result in reduced NOx emissions. 2-Ethyl-

hexyl-nitrate (EHN) is a cetane number improving fuel additive that has been shown by

others to make B20 NOx-neutral. Several treat rates of EHN in D2 and biodiesel blends


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Diesel Oxidation Catalyst - The DOC used during testing was a MINE-X P/N DC12-DQsupplied by DCL International, Concord, Ontario, Canada. The DOC had a platinum /

palladium catalyst formulation designed for oxidation of carbon monoxide (CO) andunburned hydrocarbons (HC) in diesel engine exhaust. One common application of thiscatalyst is on diesel-powered electric generators. Prior to emissions tests, the DOC was

degreened by running hot exhaust (>325 degrees C) through it for 12 hours to stabilize

its performance.

Testing Procedure - At the beginning of each test day, the engine was warmed-up by

running for one-half hour. The engine was then set to the appropriate test speed / load

condition (Table 1) and allowed to stabilize again for 15 to 20 minutes before takinggaseous or PM emission samples. The test modes were chosen based on conversations

with representatives from electric utilities. The 85 % load condition was chosen because

it is a high load condition achievable when using B85. Because of biodiesels lowerenergy content, the maximum power achievable when using high blends of biodiesel is

lower than the maximum power when using straight diesel fuel.

Table 1 - Engine speed and load modes.

Mode Speed Load Power

No. (Rpm) (N-m) (ft-lb) (%) kW Hp

1 1800 1268 935 85 235 315

2 1800 1044 770 70 193 259

3 1800 746 550 50 138 185

Measurement Techniques - Fuel consumption was determined by the carbon-balance

method. The equation for the chemically correct complete combustion of diesel fuel wasbalanced using the fuel carbon to hydrogen ratio (C/H) and the exhaust CO2 emissions.

The exhaust HC and CO emissions were neglected for this calculation. This is a good

approximation for a modern diesel engine where the HC and CO emissions are a very

small fraction, typically well less than 1%, of the CO2 emissions. Combining the relativefuel flow rate determined by the carbon balance with the measured mass airflow rate, the

fuel mass flow rate is determined. The C/H ratios used for these calculations were 1.727

for the baseline D2, 1.753 for B20, and 1.813 for B85. These ratios were determinedbased on analysis of C/H/O mass percentages. The fuel rates determined by this method

are best used on a relative basis.


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PM emissions were measured using a Sierra Instruments' Model BG-2 Micro-Dilution

Test Stand, which complied with the EPA off-highway PM measurement criteria.Samples were collected using 90-mm diameter sample filters. Typically, the amount ofPM mass collected ranged from 0.9 mg to 2+ mg. A dilution ratio was selected that

maintained the filter face temperature at 30 - 42o C for all sampling conditions. Sample

times ranged from 2 to 8 minutes. The sample filters (T60A20 Teflon-coated 90-mmglass fiber) were manufactured by Pall-Gelman Sciences Co.

A clean room was used for equilibration and weighing the mass samples, as well as

determination of the volatile portion of the PM by vacuum sublimation.Prior to weighing, the filters were conditioned overnight in the clean room that was

maintained at approximately 20 C and 50 % humidity. Following conditioning, each

filter was pre-weighed using a Mettler AT261 DeltaRange balance. After sampling, thefilters were again conditioned overnight before post-weighing. The pre-weights were

subtracted from the post-weights to determine the amount of PM collected on each filter.

The samples, except those to be used for sulfate analysis, were then baked in a vacuumoven for two hours at 200 o C and ~200 millitorr vacuum. During baking, the volatile

material is removed leaving only nonvolatile material on the filter. The volatile portionincludes volatile organic PM and hydrated sulfate. Baked filters were again conditioned

for two hours and re-weighed (after-oven weights). The difference between the post-weight and the after-over-weight was the volatile mass.

During each test where PM samples were obtained, four PM samples were collected ateach engine mode to determine the total mass, the volatile and nonvolatile fractions, and

sulfates. The exhaust PM mass concentrations were calculated for each sample, and the

sample weights for each mode were averaged. Interpol Laboratories in Circle Pines,Minnesota, conducted sulfate analysis of one sample from each mode.

Preliminary Laboratory Testing

At the onset of testing, the effect of the EHN fuel additive at varying treat rates on NO xemissions was not known. Its performance at different engine modes and at different

charge-air temperatures, and when used with biodiesel blends, could not be predicted.

Therefore, it was necessary to conduct a series of screening tests, such that the results of a

test series dictated the details of the subsequent test. Since NOx was the primarypollutant of interest at this phase of testing, only the concentration of NOx and other

gaseous emissions were measured, no PM sampling was conducted, and brake-specific

emissions of pollutants were not calculated.


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During these tests several problems were uncovered that had to be resolved before testingcould continue: (1) hysteresis effects of fuel meter, (2) excessive fuel temperature, (3)

control of engine intake air temperature, and (4) NOx emissions not responsive to theEHN fuel additive, and discovery that the wrong diesel fuel had been delivered by thefuel supplier.

Hysteresis effects of fuel meter - Use of the mass flow meter for determining fuelconsumption rate was terminated to avoid hysteresis effects when changing fuels.

Because the fuel meter contains an intricate re-circulating flow circuit, trace amounts of a

particular fuel blend remaining in the system could possibly contaminate subsequent test

fuels. We revised our procedure and drew fuel directly from barrels containingindividual fuel blends. However, this created excessive fuel temperatures.

Excessive fuel temperature - During testing, the fuel being recirculated from the engineback to the barrel gained heat from the engine. Over time, the temperature of the fuel in

the barrel became excessive, affecting engine performance. For example, at the onset of

testing the fuel temperature would start out at about 27 degrees C. After about two hours,the fuel temperature would reach 60 to 65 degrees, and the engine would not hold the

speed and load set points. The high fuel temperatures can also affect engine emissions.To remedy this problem, a shell-and-tube heat exchanger that used house water for

cooling was installed to lower the temperature of the fuel. The house water flow wasmanually adjusted to keep the temperature of the fuel to the engine between about 33 and

38 degrees C.

Control of engine intake air temperature Because the temperature of the engine intake

air directly affects NOx emissions it became very important to hold this temperature

steady while emissions measurements were taken. To simulate an aftercooler that wouldnormally be used in a genset installation, an air-to-water heat exchanger was used to

control the engine intake air temperature. The water supply to the heat exchanger wascontrolled manually with a gate valve located in the engine room. This set-up was not

ideal because the engine intake air temperature would drift due to changing ambient air

temperature and city water pressure. During testing, it was necessary to constantly enterthe engine room to adjust the gate valve, and this resulted in a wide variation in engine

intake air temperature. The remedy was to install a pneumatic pinch valve in the city

water line and adjust water flow to the heat exchanger remotely from the engine operators

position in the control room with an air regulator.

NOx emissions not responsive to the EHN fuel additive The D2+ fuel was first used to

establish a baseline followed by blends of B20, and B20 with three treat rates of EHN.o


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Fuel Mode Charge-air NOx EmissionsChange in NOx

Temperature (oC) (ppm) (%)

Baseline D2+ 1 90.5 549 0

B20 * 1 87.5 558 1.6%

B20 + 0.2% EHN 1 90.0 557 1.5%

B20 + 0.5% EHN 1 89.5 557 1.5%

B20 + 1% EHN 1 89.7 557 1.5%

* Average of 3- tests

The NOx emissions did not respond as expected to the EHN fuel additive. Whileinvestigating, we found that the fuel vendor mistakenly sent a premium fuel

(Performance Gold Plus) instead of the Performance Gold that was ordered. In error, we

received 16 barrels of Performance Gold Plus and 16 barrels of B20 and 16 barrels of

B85 blended with the higher cetane Gold Plus.

Based on information from Ethyl Corporation, we learned that EHN is routinely added at

refineries to raise the cetane number of diesel fuel. We also learned that EHN has adiminished response and can even increase NOx with higher cetane fuels.

Because Performance Gold fuel (not Gold Plus) was routinely used in diesel generatorsbeing considered for the field demonstration, 4 barrels of Performance Gold D2, 8 barrels

of B20, and 8 barrels of B85 fuel were procured.

Screening Tests

Three series of tests were conducted to: 1) quantify the increase in NOx when using

biodiesel blends made with Performance Gold, 2) evaluate EHN with B20 made with

Performance Gold, and 3) evaluate lower concentrations of EHN, and to verify the results

of previous testing. NOX emissions varied from day-to-day. Whenever possible, only the

results from one day of testing were used to determine the change in NOx emissionsusing EHN.

Screening tests to determine B20 and B85 NOx emissions - Testing resumed with the new

Performance Gold (D2) base fuel, and blends of B20 and B85. Two engine modes were

run and the concentration of NOx was measured at three charge-air cooler temperatures


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for the D2 fuel decreased the concentration of NOx by 27%. Reductions of 23-25% wereobserved when B20 and B85 were evaluated.

Table 3 - Effect of Performance Gold (D2) and biodiesel

blends on NOx emissions.



Baseline D2 1 90 569

B20 1 91.9 578 1.6B85 1 90.7 582 2.3

Baseline D2 1 62.4 466

B20 1 65.1 488 4.7

B85 1 64.4 491 5.4


B20 1 46.7 447 8.2

B85 1 46.8 439 6.3


B20 2 90.9 535 4.1

B85 2 90 563 9.5


B20 2 65.6 444 -0.2

B85 2 64.2 477 7.2


B20 2 43.4 391 1.6

B85 2 44 421 9.4

Screening tests to determine B20 NOx emissions with EHN - In the next series of

experiments, the EHN fuel additive was added to B20 at concentrations of 0.2 and 0.5%.As shown in Table 4, two engine modes were run at three charge-air cooler temperatures.

NOx emissions of the B20 with EHN additive are compared to plain B20 NOx levels. Theconcentration of NOx in the exhaust increased with increasing levels of EHN. At a

concentration of 0.2% EHN, NOx increased 0.2 to 8.5%, likewise at the 0.5%

concentration of EHN NOx increased 4 9 to 10 7% After discussions with Ethyl


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Table 4 - Effect of EHN on B20 NOx emissions.



B20 1 89.9 534 n/a

B20+0.2% EHN 1 91 570 6.7

B20+0.5% EHN 1 89 577 8.1

B20 1 65 462 n/a

B20+0.2% EHN 1 65.7 484 4.8

B20+0.5% EHN 1 64.8 501 8.4

B20 1 49 429 n/a

B20+0.2% EHN 1 46.5 434 1.2

B20+0.5% EHN 1 47.3 450 4.9

B20 2 90.1 484 n/aB20+0.2% EHN 2 90.2 501 3.5

B20+0.5% EHN 2 89.8 534 10.3

B20 2 65.6 402 n/a

B20+0.2% EHN 2 65.3 434 8.0

B20+0.5% EHN 2 64.9 445 10.7

B20 2 44.2 366 n/aB20+0.2% EHN 2 45.3 397 8.5

B20+0.5% EHN 2 45.2 404 10.4

Screening tests to evaluate lower concentrations of EHN, and to verify the results of

previous testing - The next series of screening tests were designed to: 1) test lower

concentrations of EHN in both B20 and B85, 2) repeat B20 and B85 emissions tests

without EHN to verify previous results, and 3) determine if the EHN additive wouldresult in reduced NOx emissions in the baseline D2 fuel. Again, two modes were run with

three charge-air cooler temperatures at each mode. The concentration of NOx from D2with 0.1% EHN, B20, B20 with 0.1% EHN, B85, and B85 with 0.05% EHN are

compared to the D2 fuel in Table 5.


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Table 5 - Effects of Performance Gold (D2) and biodiesel blendswith EHN on NOx emissions.


Temperature (oC) (ppm) (%)Baseline D2 * 1 90.5 640 n/aD2+0.1% EHN 1 92 639 -0.2D2+0.1 (repeat) 1 90.7 633 -1.1B20 1 90.5 651 1.7B20+0.1% EHN 1 91.4 656 2.5B85 1 90.4 665 3.9B85+0.05% EHN 1 91 667 4.2

Baseline D2 * 1 64.4 539 n/aD2+0.1% EHN 1 65.6 534 -0.9D2+0.1 (repeat) 1 65.7 532 -1.3B20 1 64.7 554 2.8B20+0.1% EHN 1 65.1 552 2.4B85 1 64.8 566 5.0B85+0.05% EHN 1 65.1 559 3.7Baseline D2 * 1 44.6 463 n/a

D2+0.1% EHN 1 42.5 452 -2.4D2+0.1 (repeat) 1 42.9 454 -1.9B20 1 44.4 474 2.4B20+0.1% EHN 1 42.5 468 1.1B85 1 46.6 492 6.3B85+0.05% EHN 1 44.4 485 4.8Baseline D2 * 2 92.1 591.5 n/aD2+0.1% EHN 2 90.8 600 1.4D2+0.1 (repeat) 2 90.8 591 -0.1

B20 2 91.9 618 4.5B20+0.1% EHN 2 90 614 3.8B85 2 90.9 638 7.9B85+0.05% EHN 2 90.6 643 8.7Baseline D2 * 2 66.1 495.5 n/aD2+0.1% EHN 2 63.5 499 0.7D2+0.1 (repeat) 2 63.6 499 0.7B20 2 65.5 501 1.1

B20+0.1% EHN 2 64.9 514 3.7B85 2 65.4 538 8.6B85+0.05% EHN 2 64.9 545 10.0Baseline D2 * 2 41.8 423 n/aD2+0.1% EHN 2 41.9 420 -0.7D2+0 1 (repeat) 2 42 9 425 0 5


22/40

The 0.1% EHN fuel additive marginally changed NOx emissions from the D2 fuel.Depending on the charge-air cooler temperature, the range of the NOx change was 2.4 %

to +1.4 %. There was little change when using 0.1% EHN in B20 and 0.05% in B85,compared to plain B20 and B85. It was at this point in the screening tests that weconcluded the EHN fuel additive would not offset the increase in NO x when using B20 or

B85, and that additional testing of this potential NOx reduction technique was not

justified.

NOx reductions due to charge-air cooling temperate were similar to results from previous

screening tests.

Emissions Tests of B20 and B85 with Charge-Air Cooling and DOC

Emissions tests were conducted to determine the effect of B20 and B85 combined withthe use of a DOC and charge-air cooling. The emissions testing was significantly more

involved than the screening tests. During emissions testing, the engine was run at modes

1 and 3, with charge-air temperatures of about 40o, 65

o, and 90

oC. During each test, four

PM samples were taken at each mode/charge-air temperature combination. One of every

four samples was sent to an outside laboratory for sulfate analysis.

Concentrations of total PM, volatile PM, nonvolatile PM, and sulfate PM were calculatedfrom the mass of exhaust flowing through the filter, the dilution ratio, and sample

weights. Gaseous emissions concentrations were measured directly. Engine exhaust

flows were determined by summing the mass intake airflow and the fuel rates. Massemission rates were then calculated using exhaust concentrations and exhaust emission

rates. Results are reported on a brake horsepower-specific basis. Complete emissions

data are in Appendix F.

As expected, the DOC was very effective in reducing HC and CO emissions from allfuels, independent of charge-air temperature. However, the effect of the DOC on these

gaseous emissions will not be discussed because they are of lesser importance to this

study. Emphasis was on the effect of the DOC on NOx and PM emissions.

In the discussion that follows the brake specific NOx and PM emissions using

Performance Gold, B20, B85, and the DOC are compared. The emissions at modes 1 and

3 were averaged for each charge-air temperature. The changes in emissions that aregiven in the tables and that appear throughout the discussion are based on a baseline

condition of Performance Gold with a charge-air temperature of 90o C, meant to represent

a jacket-water aftercooled engine. The emissions using B20 and B85 with and without a


23/40

lower energy content of the biodiesel fuel. The increase in fuel consumption ranged from1.6 to 3.7 % when using B20, and 7.0 to 10.7 % when using B85.

Table 6 - BSFC using Performance Gold (D2), B20 and B85

BSFC (g/bhp-hr)Change in BSFC

(%)

Mode

Charge-airtemperature

(oC) D2 B20 B85 B20 B85

1 90.0 162.8 168.7 174.2 3.7 7.0

1 65.0 161.7 165.3 173.9 2.2 7.5

1 40.0 160.3 163.7 173.6 2.1 8.3

3 90.0 159.5 163.1 176.6 2.3 10.7

3 65.0 158.1 161.9 174.7 2.4 10.5

3 40.0 157.2 159.8 172.6 1.6 9.8

The neat biodiesel fuel had a significantly lower heating value (12.8 % on a mass basis)

than the diesel fuel (Table 7). The heating value of the blend is proportional to thebiodiesel concentration. However, the density of biodiesel is greater than diesel fuel, sothe effect on volumetric energy content (Btu/gal) is not as great. As shown in table 7, the

measured energy content of the B20 fuel was 2.2 % lower on a mass basis, and the

energy content of the B85 was 11.1 % lower. These values are similar to the change infuel consumption using the biodiesel blends that were observed during the lab test.

Table 7 - Energy content of Performance Gold (D2), B20, andB85 fuels

Fuel Heat ofcombustion

(BTU/lb)

Heat ofcombustion

(BTU/gal)

Change fromD2 (% mass

basis)

Change fromD2 (%

volumebasis)

D2 19,292 140,234 na Na

B20 18,871 137,513 -2.2 -2.0

B85 17,369 127,818 -11.1 -9.7B100 17,105 126,286 -12.8 -11.0

Baseline testing of Performance Gold (D2) with Charge-Air Cooling - As noted

previously the charge-air temperature was very effective at lowering NOx Reducing the


24/40

function of charge-air temperature

Fuel Mode

Charge-airTemperature

(oC)

NOxEmissions

(g/bhp-hr)

Total PMEmissions(g/bhp-hr)

Volatile PMEmissions(g/bhp-hr)

Nonvolatile PMEmissions(g/bhp-hr)

D2 1 90.3 4.05 0.059 0.022 0.037

D2 1 64.1 3.56 0.052 0.015 0.037

D2 1 39.9 3.06 0.057 0.016 0.041

D2 3 90.4 4.44 0.098 0.033 0.065

D2 3 65.8 3.85 0.109 0.034 0.075

D2 3 40.2 3.45 0.101 0.036 0.065

Fuel Mode


(oC)

Change inNOx

Emissions(%)

Change inTotal PM

Emissions (%)

Change inVolatile PM

Emissions (%)

Change inNonvolatile PMEmissions (%)

D2 1 90 na na na na

D2 1 64 -11.9 -11.8 -31.0 0

D2 1 40 -24.5 -3.2 -27.9 11.2

D2 3 90 na na na na

D2 3 66 -13.5 11.0 2.0 15.6D2 3 40 -22.4 2.7 10.1 0

Performance Gold (D2) versus B20 - The use of B20 resulted in about a 6% increase in

NOx at the mode 1, 90o C condition, but significant reductions were observed using B20

at lower charge-air temperatures. Total PM was reduced from 11 to 18 %. NonvolatilePM decreased 29 to 36 % (Table 9).

Table 9 - Effect of Performance Gold (D2) and B20 on NOx and PMEmissions

Fuel


(oC)

NOxEmissions(g/bhp-hr)



Nonvolatile PMEmissions (g/bhp-

hr)

D2 90.4 4.24 0.079 0.027 0.051

B20 91.1 4.48 0.064 0.031 0.033B20 64.8 3.88 0.067 0.031 0.036

B20 41.6 3.42 0.070 0.033 0.036


Change inNOx

Emissions

Change inTotal PM

Emissions

Change inVolatile PMEmissions

Change inNonvolatile PM


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Performance Gold (D2) vs. B20 with DOC - The same trend in NOx emissions as abovewas observed when using a DOC with B20. NOx emissions again increased about 5% at

the 90o C condition, but decreased by 21 % when the charge-air was cooled to 40o C

(Table10). However, PM emissions increased 25 to 51%, depending on charge-airtemperature. Most of the increase in PM was due to an increase in volatile emissions

resulting from the DOC oxidizing fuel sulfur to sulfate. An increase in nonvolatile

emissions was also observed. The PM emissions varied with charge-air temperature.

Table 10 - Effect of Performance Gold (D2) and B20 with DOC on NOxand PM Emissions

Fuel


(oC)




NonvolatilePM

Emissions(g/bhp-hr)

D2 90.4 4.24 0.079 0.027 0.051

B20 w/ DOC 90.4 4.44 0.118 0.058 0.060

B20 w/ DOC 65.1 3.91 0.112 0.049 0.063

B20 w/ DOC 40.9 3.35 0.098 0.043 0.055

Fuel


(oC)

Change inNOx

Emissions(%)

Change inTotal PM

Emissions(%)


(%)

Change inNonvolatilePM

Emissions(%)

B20 w/ DOC 90 4.7 50.8 113.6 17.4B20 w/ DOC 65 -7.8 42.2 80.1 22.0B20 w/ DOC 40 -21.0 24.9 57.1 7.7

Performance Gold (D2) versus B85 - As expected, NOx emissions increased using B85

without reducing charge-air temperature (Table 11). The increase was almost completely

offset when cooling the charge-air to 65o

C, and a reduction of 15 % was measured at acharge-air temperature of 40o C. Total PM emissions dropped by 24 to 28 %. A

nonvolatile PM reduction that exceeded 70 % was partially offset by an increase in

volatile emissions that exceeded 60%.

Performance Gold (D2) versus B85 with DOC - The NOx emissions were similar to B85without the catalyst, with a 14 % increase observed at 90o C, the increase being offset at

65o

C, and an 11% reduction observed at 40o

C (Table 12). Overall, total PM emissionswere reduced 31 to 45 %. Again, a large decrease of 62 to 70 % in nonvolatile emissions

was measured, while volatile emissions still showed an increase due to sulfate formation.


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Fuel


(o

C)

NOxEmissions

(g/bhp-hr)

Total PMEmissions

(g/bhp-hr)

Volatile PMEmissions

(g/bhp-hr)

NonvolatilePM

Emissions

(g/bhp-hr)D2 90.4 4.24 0.079 0.027 0.051

B85 90.3 4.78 0.056 0.044 0.012B85 65.5 4.18 0.058 0.044 0.014B85 41.9 3.58 0.059 0.045 0.014

Fuel


(oC)

Change inNOx

Emissions

(%)

Change inTotal PM

Emissions

(%)


(%)

Change inNonvolatile

PMEmissions

(%)B85 90 12.6 -28.7 61.6 -76.7B85 65 -1.5 -26.0 61.2 -72.4B85 40 -15.6 -24.2 66.0 -72.3

Table 12 - Effect of Performance Gold (D2) and B85 with DOC on NOxand PM Emissions

Fuel


(oC)




NonvolatilePM

Emissions(g/bhp-hr)

D2 90.4 4.24 0.079 0.027 0.051B85 w/ DOC 89.6 4.85 0.054 0.035 0.019

B85 w/ DOC 65.2 4.21 0.047 0.029 0.018B85 w/ DOC 43.4 3.77 0.043 0.028 0.016

Fuel


(oC)

Change inNOx

Emissions(%)

Change inTotal PM

Emissions(%)


(%)


PMEmissions

(%)

B85 w/ DOC 90 14.3 -31.6 26.7 -62.6

B85 w/ DOC 65 -0.8 -40.3 7.0 -65.5

B85 w/ DOC 40 -11.1 -45.0 0.9 -69.4

Performance Gold (D2) vs. Performance Gold Plus (D2+) -In Table 13, the NOx and


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Fuel


(o

C)

NOxEmissions

(g/bhp-hr)

Total PMEmissions (g/bhp-

hr)

Volatile PMEmissions

(g/bhp-hr)

NonvolatilePM

Emissions

(g/bhp-hr)D2 90.3 4.05 0.059 0.022 0.037

D2+ 90.5 3.89 0.043 0.012 0.032

Fuel


(oC)

Change inNOx

Emissions(%)

Change in TotalPM Emissions (%)


(%)


PMEmissions

(%)

D2+ 90.0 -4.0 -26.2 -46.7 -14.4

Laboratory Test Conclusions:

Ethyl-Hexyl Nitrate (EHN) fuel additive- The screening tests demonstrated that the EHN

was not effective at reducing NOx emissions from biodiesel blends made from either the

Performance Gold or Performance Gold+ diesel fuels.

Brake specific fuel consumption (BSFC) - Due to the lower energy content of biodiesel,

the BSFC increased when using biodiesel blends. The increase was proportional to the

biodiesel fraction in the blend. B20 increased BSFC by 2 to 4 %, depending on enginemode and charge-air temperature, while an increase of 7 to 11 % was observed using

B85.

Charge-air Temperature - Reducing charge-air temperature was very effective at reducing

brake specific NOx emissions. When evaluated with the baseline diesel fuel, reducingcharge-air temperature from 90o

to 40o

C lowered NOx emissions by 22 to 25 %. Therewas no clear trend regarding PM emissions, with the emissions decreasing with charge-

air temperature at mode 1, and increasing at mode 3.

Performance Gold Plus Diesel Fuel - A limited comparison of Performance Gold Plus

(D2+) to Performance Gold (D2) was conducted. A 4% reduction in NOx, and a 26%

reduction in PM emissions was measured at mode 1 at a charge-air temperature of 90o C

with D2. More complete tests are required for verification.

B20 -Brake specific NOx increased by about 6% using B20, but was reduced 19 % whenthe charge-air temperature was lowered from 90o to 40oC. Total PM was reduced by 11

to 18%, depending on charge-air temperature.


28/40

the exhaust gas to sulfate, which is measured as volatile PM. This was especiallysignificant using B20, with increases of up to 50% in total PM observed. This effect was

much less pronounced using B85 because of the lower sulfur content of this fuel blend.

However, using fuels that are currently available, the use of a DOC may not a goodapplication on diesel generators due to the oxidation of fuel sulfur to sulfate.

In 2006, ultra-low sulfur diesel fuel will become available nationwide. Fuel sulfur levelsof under 15 ppm are proposed, versus the 500-ppm sulfur limit that now exists. The

future availability of ultra-low sulfur diesel fuel bodes well for the use of DOCs on

diesel generators.

DEMONSTRATION ON A PEAK-SHAVING ELECTRIC GENERATOR

Background

The objective of the field demonstration was to show that B20 could be effectively usedin gensets.

The laboratory testing of biodiesel showed that the use of B20 and B85 resulted in

significant reductions in PM, CO, and HC, but increased NOx. CDR proceeded withdemonstrating a combination of B20 with supplemental charge air-cooling on a genset

installation. B20 was chosen because it provided reductions in PM, CO, and HC.

Charge-air cooling more than offset the NOx increase when using B20.

The demonstration took place at the School of Environmental Studies at the Minnesota

Zoo in Apple Valley. The Zoo School is an optional high school developed byIndependent School District #196, the Minnesota Zoological Gardens, and the City of

Apple Valley with support from Dakota County and the State of Minnesota.

The Dakota Electric Association, Energy Alternatives, and Great River Energy

cooperated to provide the demonstration site. The demonstration genset engine was aCaterpillar model 3406 B, turbocharged and jacket-water aftercooled engine. The

generator was rated 400 kW standby and 365 kW prime at 60 Hz, 1800 rpm. The

standby rating is the electric power that can be supplied for emergencies for theduration of normal power interruption. The prime rating rating is the maximum poweravailable at a variable load for an unlimited number of hours. This genset is used for

standby emergency power and off-grid peak shaving at the Zoo School.


29/40

Zoo School and with the assistance of Ziegler Power Systems of Shakopee, Minnesota, aseparate supplemental cooling circuit was designed and installed (Appendix G). This

auxiliary cooling circuit had a separate shell & tube heat exchanger cooled with city

water. This cooling circuit enabled a 40o C reduction in the temperature of the intake aircharge to the engine to be attained, which closely duplicated laboratory test conditions.

The engine was run at a constant speed of 1800 rpm and the load was adjusted with aportable load bank. Two engine loads were used throughout the field demonstration;

85%, which corresponds to 341 kW (457 hp) and 50%, which corresponds to 198 kW

(266 hp). Sampling was conducted at charge-air temperatures of 90o and 50o C. Tests

were conducted over 5 nonconsecutive days. On days 1 and 2, regular D2 diesel fuel wasrun. On days 3 and 4, B20 fuel was run. On day 5, B20 and D2 were run for day each.

Measurements of gaseous and PM mass emissions were made during the fielddemonstration. Appendix H lists the sampling procedure and sequence. Figure 3 is a

schematic diagram of the sampling equipment used. For PM sampling, exhaust was

extracted into a miniature dilution tunnel where it was diluted approximately 12:1.Following dilution, the exhaust passed through a pre-weighed Pallflex TX40H120-WW,

Teflon-coated, glass fiber 90-mm sample filter, where the PM is deposited and latergravimetrically analyzed. Three PM samples were taken at each mode/charge-air

temperature combination. For gas emissions sampling, a Testo 360 portable gas analyzerwas used to measure NOx, CO, oxygen (O2), and carbon dioxide (CO2) was calculated.

Emissions and temperature data were recorded on a Rustrac data logger and pressures

were manually recorded.

Figure 4 shows the demonstration test site, and Figure 5 shows emissions sampling being

conducted on the roof of the generator enclosure.

Test Results

For tables 14, 15, and 16, gaseous NOx and CO emissions are given in units of parts permillion (ppm) and average total PM (TPM) is given in dual units of milligrams per cubic

meter (mg/m^3). Percent changes in emissions are rounded based on spreadsheet values

with extended digits, not shown in the tables. Modes are identified by the percent engineload and nominal intake charge-air temperature, for example, 50/50 indicates a testcondition of 50% engine load and 50 degree C intake air temperature. Emissions data

from the field demonstration are given in Appendix I.


30/40

Figure 3 - Gaseous and PM emission sampling train used during field

demonstration.

Temperature

Bypass Valve

Mass Flow

Meter /

Totalizer

Mini Tunnel 1 Dilution Stage, ~12:1

Pressure / Temperature

Port

Data Logger

Gas Sampling Port

Portable Gas Analyzer

NOx

CO

O2CO2 (calculated)

90-mm PM Sam le

Pump

Exhaust

Sample Valve

Pressure


31/40

Figure 4: Demonstration site


32/40

Figure 5 - Emissions sampling on site

Table 14 is a comparison of NOx, CO, and total PM emissions for D2 and B20 at

identical engine loads and intake charge-air temperatures. NOx increased 3 to 7 percent,

CO decreased 23 to 27 percent, and total PM decreased 43 to 46 percent.

Table 14 - Comparison of NOx, CO, and Total PM emissions for D2 and B20 at identicalengine loads and intake charge-air temperatures.

Ave NOx Ave CO Ave Total PM

MODE * FUEL (ppm) (ppm) (mg/m^3)

50 / 50 D2 1054 223 1.8

50 / 50 B20 1089 168 1.0Pct. Chg. 3 -25 -44

50 / 90 D2 1333 268 1.6

50 / 90 B20 1391 195 0.9

Pct. Chg. 4 -27 -46

85 / 50 D2 983 540 4.5


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Table 15 is a comparison of NOx, CO, and PM emissions of D2 at two engine loads andtwo intake charge-air temperatures. These results show that by virtue of only reducing

intake charge-air temperature NOx can be reduced by about 25 percent and CO is reduced

18 to 21 percent. PM decreased about 9 % at the 50 % load condition, but increased 6 %at the 85 % load condition.

Table 15 - Comparison of NOx, CO, and Total PM emissions of D2 at two engine loads andtwo intake charge-air temperatures.



50 / 50 D2 1054 223 1.8

50 / 90 D2 1333 268 1.6

Pct. Chg. 26 21 -9

85 / 50 D2 983 540 4.5

85 / 90 D2 1230 635 4.8

Pct. Chg. 25 18 5.5

* Percent load / nominal charge-air temperature in degrees C

Table 16 is a comparison of NOx, CO, and PM emissions for D2 at 90o C charge-air

temperature and B20 at 50o C charge-air temperature. The results in this table are most

telling because it demonstrates emission changes due to switching from D2 with normalcharge-air temperature to B20 with supplemental charge air-cooling. Average NOxemissions are reduced 15-18 percent, CO is reduced 35-37 percent, and PM was reduced

39 to 47 percent.

Table 16 - Comparison of NOx, CO, and Total PM emissions for D2 at 90o

C charge-airtemperature and B20 at 50

oC charge-air temperature.



50 / 90 D2 1333 268 1.6

50 / 50 B20 1089 168 1.0

Pct. Chg. -18 -37 -39

85 / 90 D2 1230 635 4.8

85 / 50 B20 1048 413 2.6

Pct. Chg. -15 -35 -46

* Percent load / nominal charge-air temperature indegrees C


34/40

results. The commercial system used for the lab tests is designed to minimize samplinglosses. The field dilution apparatus may have had line losses due to condensation of

volatile material or thermophoretic deposition of PM. If this were occurring, the PM

concentrations measured during the field test were lower than actual PM emissions, andmay lead to misleading PM results. The lab results match more closely with the expected

PM reductions associated with operating an engine on B20

The difference between the lab results and field results may also be associated with 1) the

different engine technologies, with the mechanical fuel injection field test engine having

different baseline emissions than the electronically controlled lab test engine, and 2)

sampling conditions, engine load, and charge-air temperature being more difficult tocontrol in the field than in the lab.

For the field demonstration, the intake air cooling circuit was modified using a shell andtube heat exchanger and city water. In practice, modifying a jacket water aftercooled

generator to achieve additional charge-air cooling may be costly. Similar reductions in

intake air temperature may be achieved by switching from jacket-water aftercooling toair-to-air aftercooling. No attempt was made during the field demonstration to determine

the costs for making those modifications.


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36/40

APPENDIX D - Fuel ModificationTechniques

Fuel Modification Approx. Concentration Reference

Technique CO HC NOx PM Cost PROS CONS

Ethanol ** increase increase -10% decrease n/a 10% in DF#1 Decreases PM Requires cetane improver to counteract NOx increase. 2

Reduces lubricity, potential for vapor lock in return line.K50 / B50 + 2.3% DTBP *** 38.0 12.0 3.0 67.0 High concentration of expensive additive 1(50% DF# 1+B50+DTPB)

K50 / B50 *** 31.0 -39.0 -2.0 54.0 NOx increase; need catalyst for HC reduction 1(50% DF# 1 + B50)

"Bioclean" A1 in B20 *** -2.0 -7.0 -0.5 7.0 All emissions increased, except PMfuel additive

TBHQ Antioxidant in B20 *** 8.0 15.0 -1.0 12.0 NOx increase 1

(tert-butyl-hydroquinone)

Short Chain Esters in B20 *** 10.0 9.0 -3.0 21.0 NOx increase 1(methyl compounds)

DTBP Fuel Additive in B20 *** 12.0 64.0 -1.0 19.0 See CON 0.50% Increase fuel cost ~ $0.08/gal.; NOx increase 1

(di-tert-butyl peroxide)

" 12.0 -14.0 0.0 14.0 See CON 1.00% Increase fuel cost ~ $0.16/gal.; no change in NOx 1

" 16.0 43.0 3.0 19.0 See CON 1.5% 3% NOx decrease Increase fuel cost ~ $0.24/gal. 1

EHN Fuel Additive in B20 *** 11.0 43.0 0.5 16.0 See CON 0.50% Marginal, but significant, NOx decrease. Increase fuel cost ~ $0.05/gal. 1

(ethyl-hexyl nitrate) Inexpensive

" 14.0 11.0 0.5 20.0 See CON 1.00% Marginal, but significant, NOx decrease. Increase fuel cost ~ $0.10/gal. 1Inexpensive

Emulsified Fuel n/a n/a 14.0 63.0 n/a 63% PM reduction, 14% NOx reduction Large external blending unit required, OEM engine 3

(w/water & surfactant) modifications required.

In-Cylinder Water Injection n/a n/a 60.0 n/a n/a n/a Special injectors needed, developed for large marine 3engines burning heavy fuel.

Fumigation n/a n/a 70.0 n/a n/a n/a Developed for large marine engines burning heavy fuel. 3(w/water)

* n/a - not applicable or no significant change or unknown.

** Steady-State Tests, emissions changes based on concentration (ppm).

*** FTP Tests; emissions changes based on brake-specific; compared to base D2 fuel.

REFERENCES

1 NOx Solutions for Biodiesel, Final report to NREL, Aug 2001

2 Multifunctional Diesel Fuel Addi tives from Tr iglycer ides, U Kansas, Jun 2000

3 Dieselnet.com

Maximum Pollutant Reduction (%)

Appendix - Fuel Modification Techniques


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APPENDIX E - Properties of Test Fuels.

Fuel ASTM Performance Performance

Property Method Gold (D2) Gold Plus (D2+) B20 B85 B100

Flash Point (deg. C) D93 74 n/a 74 >130 126Copper Corrosion D130 1A n/a 1A 1A 1A

Heat of Combustion BTU/lb.) D240 19292 n/a 18871 17369 17105

Heat of Combustion (BTU/gal.) D240 140234 n/a 137513 127818 126286

Kinematic Viscosity (cSt@40 deg. C) D445 3.248 n/a 3.378 2.325 3.954

Carbon Residue, Ramsbottom (%) D524 0.085 n/a 0.060 0.048 0.045

Cetane Number D613 43.5 n/a 42.8 48.7 49.5

Acid Number (mg KOH/gram) D664 0.03 n/a 0.04 0.14 0.14

Sulfated Ash (mass-%) D874 0.000 n/a 0.003 0.001 0.000

Distillat ion at reduced pressure (10 mm Hg) D1160

Atmospheric Equiv. Temp. (AET) (deg. C)IBP 171 n/a 160 159 173

5% rec. 235 n/a 239 298 376

10% rec. 248 n/a 254 333 379

20% rec. 264 n/a 276 365 379

30% rec. 285 n/a 293 374 380

40% rec. 298 n/a 313 377 381

50% rec. 311 n/a 329 379 382

60% rec. 324 n/a 346 381 382

70% rec. 338 n/a 360 382 383

80% rec. 351 n/a 368 383 383

90% rec. 367 n/a 379 383 38495% rec. 384 n/a 386 384 386

FBP 412 n/a 406 399 394

Specific Gravity (g/mL@15 deg. C) D1298 0.8714 n/a 0.8740 0.8822 0.8844

Aromatics by FIA (vol.-% Aromatics) D1319 46.1 n/a n/a n/a n/a

Olefins by FIA ((vol.-% Olefins) D1319 3.6 n/a n/a n/a n/a

Hydrocarbons by FIA (vol.-% saturates) D1319 50.3 n/a n/a n/a n/a

Water and Sediment (vol.-%) D2709 0.000 n/a 0.005 0.000 0.000

Instrumental Determination of C, H, N, and O2 D5291

Carbon (mass-%) 87.14 n/a 84.99 78.59 77.21

Hydrogen (mass-%) 12.63 n/a 12.50 11.96 11.97

Nitrogen (mass-%) 0.00 n/a 0.74 0.75 0.67Oxygen (mass-%) 0.23 n/a 1.77 8.70 10.15

Total Sulfur by UV Fluorescence (mass-%) D5453 0.03497 n/a 0.02627 0.00508 0.00005

Cloud Point (deg. C) D5773 -14 n/a -12 2 0

Pour Point (deg. C) D5949 -33 n/a -27 -9 -6

Cold Filter Plugging Point (deg. C) D6371 -18 n/a -16 -8 -6

2-Ethyl Hexyl Nitrate (EHN) (ppmv) (2) (3) 1190 362 see Table _ see Table _ 0

Footnotes:

(1) Analysis performed by Williams Laboratory Services unless otherwise noted (results reported as received)

(2) Analysis performed by Ethyl Corporation (results reported as received)(3) Varlen Instruments Petrospec Cetane 2000 diesel fuel analyzer used for analysis

(4) Calculated EHN values

Appendix F - Biodiesel in Generators: Summary of brake specific emissions


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Baseline: Performance Gold Diesel Fuel

Fuels/emission controls

1) Charge air cooling: Charge air temperatures of 90, 65, 40 C

2) Performance Gold Plus Diesel Fuel

3) B20 (made with Performance Gold and SME)

4) B20 with Catalyst

5) B85 (made with Performance Gold snd SME)

6) B85 with Catalyst

Engine modes/ charge air cooling temperatures

Mode 1: Rated speed/85% load with w/ CACT's of 90, 65, 40 C

Mode 3: Rated speed/50% load with w/ CACT's of 90, 65, 40 C

Results

Performance Gold vs Performance Gold Plus

Mode

Charge air

temp

BSFC (g/bhp

hr)

HC (g/bhp-

hr)

CO (g/bhp-

hr)

CO2 (g/bhp-

hr)

NOx (g/bhp-

hr)

TPM

Emissions

(g/bhp-hr)

Volatile PM

Emissions

(g/bhp-hr)

Nonvolatile

PM Emissions

(g/bhp-hr)

Sulfate PM

Emissions

(g/bhp-hr)

Ave BS emissions PG 1 90.3 162.8 0.28 0.29 539.10 4.05 0.059 0.022 0.037 0.009

3 65.8 158.1 0.33 0.44 518.44 3.85 0.109 0.034 0.075 0.002

PG+ 1 90.5 160.3 0.11 0.29 535.17 3.89 0.043 0.012 0.032 0.002

3 62.6 157.8 0.15 0.40 519.64 3.81 0.082 0.031 0.051 0.001

% change emissions 1 90 1.5 61.0 -2.0 0.7 4.0 26.2 46.7 14.4 77.1

3 62-66 0.2 55.3 8.0 -0.2 1.1 24.7 6.4 32.8 10.8

Performance Gold vs B20

Ave BS emissions PG 1,3 90.4 161.1 0.30 0.34 531.43 4.24 0.079 0.027 0.051 0.005

1,3 64.9 159.9 0.31 0.36 526.61 3.70 0.080 0.024 0.056 0.004

1,3 40.1 158.8 0.30 0.36 522.18 3.25 0.079 0.026 0.053 0.002

B20 1,3 91.1 165.9 0.28 0.33 537.33 4.48 0.064 0.031 0.033 0.002

1,3 64.8 163.6 0.28 0.33 529.48 3.88 0.067 0.031 0.036 0.002

1,3 41.6 161.7 0.27 0.33 522.73 3.42 0.070 0.033 0.036 0.002

% change emissions 1,3 91.8 -3.0 7.0 4.7 -1.1 -5.6 18.1 -14.6 35.6 62.4

1,3 65.0 -2.3 8.6 6.9 -0.5 -4.8 17.4 -27.0 36.5 52.5

1,3 43.3 -1.9 11.3 7.4 -0.1 -5.2 11.8 -28.7 31.6 15.8

Performance Gold vs B20 with Catalyst


1,3 64.9 159.9 0.31 0.36 526.61 3.70 0.080 0.024 0.056 0.004

1,3 40.1 158.8 0.30 0.36 522.18 3.25 0.079 0.026 0.053 0.002

B20 w DOC 1,3 90.4 165.3 0.11 0.09 535.57 4.44 0.118 0.058 0.060 0.0541,3 65.1 166.0 0.11 0.09 537.43 3.91 0.112 0.049 0.063 0.047

1,3 40.9 161.9 0.10 0.09 523.56 3.35 0.098 0.043 0.055 0.037

% change emissions 1,3 91.8 -2.6 65.5 74.2 -0.8 -4.7 -50.8 -113.6 -17.4 -921.3

1,3 65.0 -3.8 65.1 74.3 -2.1 -5.6 -38.8 -102.6 -11.2 -1059.7

1,3 43.3 -2.0 65.6 74.8 -0.3 -3.1 -24.2 -65.3 -4.1 -1672.3

Performance Gold vs B85


1,3 64.9 159.9 0.31 0.36 526.61 3.70 0.080 0.024 0.056 0.004

1,3 40.1 158.8 0.30 0.36 522.18 3.25 0.079 0.026 0.053 0.002

B85 1,3 90.3 175.4 0.23 0.24 523.90 4.78 0.056 0.044 0.012 0.004

1,3 65.5 174.3 0.23 0.26 520.20 4.18 0.058 0.044 0.014 0.0021,3 41.9 173.1 0.23 0.28 516.10 3.58 0.059 0.045 0.014 0.001

% change emissions 1,3 91.8 -8.9 24.6 28.9 1.4 -12.6 28.7 -61.6 76.7 29.1

1,3 65.0 -9.0 24.2 27.2 1.2 -12.8 27.8 -81.3 74.8 50.9

1,3 43.3 -9.0 25.7 22.8 1.2 -10.2 24.6 -74.8 73.2 34.5

Performance Gold vs B85 with Catalyst



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Appendix I - Zoo School Demonstration: Gaseous emissions data

Mode Date Fuel Time % O2 ppm CO ppm NO ppm NO2 ppm NOx85 hot 5/6/03 D2 13:14:45 8.31 662 1178 29.6 1208

85 hot 5/6/03 D2 13:39:19 8.33 673 1145 38.8 1184

85 hot 5/6/03 D2 14:15:51 8.23 691 1141 42.2 1183

85 cold 5/6/03 D2 14:36:55 8.89 581 938 27.2 966

85 cold 5/6/03 D2 14:51:47 8.86 596 935 19.2 954

85 cold 5/6/03 D2 15:11:59 8.89 562 931 25.0 956

50 hot 5/6/03 D2 16:00:05 9.00 317 1250 36.8 1287

50 hot 5/6/03 D2 16:14:58 9.02 302 1255 36.2 1291

50 hot 5/6/03 D2 16:30:59 9.04 300 1260 36.6 1297

50 cold 5/6/03 D2 17:12:30 9.80 264 1016 31.2 1047

50 cold 5/6/03 D2 17:28:52 9.84 265 994 31.4 1025

85 hot 5/7/03 D2 11:17:47 8.28 602 1249 22.6 1271

50 hot 5/7/03 D2 12:10:20 9.08 236 1332 32.6 1364

50 hot 5/7/03 D2 12:44:20 9.06 224 1302 33.2 1335

85 cold 5/7/03 D2 13:28:21 8.91 487 966 19.0 985

86 cold 5/7/03 D2 13:45:11 8.89 501 978 14.8 992

50 cold 5/7/03 D2 14:20:53 9.89 201 1021 23.0 1044

50 cold 5/7/03 D2 14:54:21 9.86 200 1027 25.0 1052

85 hot 5/8/03 B20 12:57:27 8.40 543 1134 102.9 1237

50 hot 5/8/03 B20 13:47:11 9.25 213 1262 107.5 1370

50 hot 5/8/03 B20 14:25:36 9.25 214 1252 102.7 1355

85 cold 5/8/03 B20 14:59:30 9.07 430 943 76.1 1019

85 cold 5/8/03 B20 15:19:48 9.07 420 942 74.3 1016

50 cold 5/8/03 B20 15:58:17 9.98 181 1005 61.5 1067

50 cold 5/8/03 B20 16:28:25 9.96 176 1007 58.0 1065

85 hot 5/12/03 B20 10:29:08 8.59 443 1198 154.0 135285 hot 5/12/03 B20 10:57:11 8.50 454 1195 157.3 1352

50 hot 5/12/03 B20 11:31:57 9.33 190 1278 115.8 1394

50 hot 5/12/03 B20 11:56:21 9.40 188 1269 109.6 1379

50 hot 5/12/03 B20 12:22:02 9.35 187 1280 105.1 1385

85 cold 5/12/03 B20 13:03:49 9.10 409 975 74.2 1050

50 cold 5/12/03 B20 14:00:28 10.00 169 1051 53.7 1105

50 cold 5/12/03 B20 14:28:53 10.07 173 1016 50.8 1067

85 hot 5/13/03 B20 9:58:42 8.40 462 1139 163.3 1303

50 hot 5/13/03 B20 10:31:40 9.15 179 1311 153.4 146485 cold 5/13/03 B20 11:04:53 8.98 395 999 107.6 1107

50 cold 5/13/03 B20 11:38:43 10.00 140 1073 69.9 1143

85 hot 5/13/03 D2 12:51:13 8.20 546 1173 130.9 1304

50 hot 5/13/03 D2 13:18:39 9.00 232 1293 131.1 1424

85 cold 5/13/03 D2 13:44:10 8 90 475 973 80 4 1053


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Documents

Air Quality Testing of Biodiesel