Biodiesel Program

Measurement of Biodiesel Speed of Sound and Its Impact on Ignition Timing

Research Funded by: U.S. Department of Energy Office of Fuels Development through the National Renewable Energy Laboratory

Project Manager: Robert Wooley 303.384.6825, Robert_Wooley@nrel.gov

Performing Organization: University of Iowa, 213 Beardshear Hall, Ames, IA 50011

Principal Investigator: Jon Van Gerpen, 515.294.5563, jvg@iastate.edu

Contract Number: ACG-8-18066-01

Contract Period: 06/98–06/00

Contract Funding:

FY 1998: $25,505

Objectives: This project will measure the bulk modulus and speed of sound of biodiesel and estimate the effect of these fuel properties on the ignition timing of compression ignition engines that use biodiesel.

Approach/Background: The speed of sound of a fuel can affect the performance of some types of fuel injection systems, reducing the time for the pressure pulses to travel from the injection pump to the injector. A related factor is the compressibility of the fuel. All injection systems compress more fuel that is injected. A fuel that is less compressible, such as biodiesel, will inject prematurely. The bulk modulus and speed of sound of fuels are related to each other and to fuel density through mathematical relationships. By measuring a fuel’s speed of sound and density, the adiabatic bulk modulus can be calculated. These properties can then be associated with fuel injection performance on biodiesel.

The contractor will construct a speed-of-sound measurement system and will validate the system with known fuels and their speed-of-sound properties. After validation and any necessary adjustments, the contractor will then test several biodiesel fuels and a broad range of biodiesel fuel components, better known as specific types of fatty acid methyl esters. Each type of fatty acid methyl ester will differ by number of carbons in the chain, number of double bonds, or both. This test will determine which components of biodiesel create the most difference between biodiesel and diesel fuel properties. This information could help in the design of a feedstock that minimizes undesirable fatty acids and maximizes desirable fatty acids.

Status/Accomplishments: The project is nearly complete. Data on density, speed of sound, and isentropic bulk modulus have been collected for 21 ethyl and methyl ester fatty acids and blends of fatty acids from 20^o–100^oC. There is a significant difference between these properties for biodiesel and No. 2 diesel fuel, similar but in the opposite direction as the differences between No. 1 and No. 2 diesel fuel. Speed of sound and bulk modulus appear to cause ignition timing to advance by an average of one degree. This tendency contributes to some but not all of the increase in NO_x emissions commonly seen in biodiesel engine stand emission tests.

This information could be used by original equipment manufacturers interested in designing a B100 engine or vehicle for sale as an alternative-fuel vehicle. This information could also be used to support efforts to retard engine timing, although research on timing retardation with biodiesel and biodiesel blends show other emissions increasing when this occurs. A B100 engine–vehicle system may eliminate or reduce the amount of NO_x produced by biodiesel fuels, although a significant amount of engine mapping and research on fuel spray patterns, droplet size, droplet density, and other systems would be needed to accomplish this. Some of this research is underway in other projects.

Publications and Presentations:

1. 2000 Biodiesel Research Brainstorming and Coordination Workshop, Phoenix, AZ. Feb. 2, 2000.
2. Measurement of speed of sound and its impact on injection timing, draft final report. 2000 (in peer review). NREL plans to publish the report this year.

Summary Date: March 2000

Tier II Health Effects Testing

Research Funded by: U.S. Department of Energy Office of Fuels Development through the National Renewable Energy Laboratory

Project Manager: Robert Wooley 303.384.6825, Robert_Wooley@nrel.gov

Performing Organization: National Biodiesel Board, 1907 Williams Street, P.O. Box 104898, Jefferson City, MO 65110-4898

Principal Investigator: Steve Howell, 816.635.5772, showell@marciv.com

Contract Number: ACO-8-18111-01

Contract Period: 09/98–05/00

Contract Funding:

FY 1998: $87,469

Objectives: This project will meet U.S. Environmental Protection Agency (EPA) Tier II requirements for the registration of biodiesel as a fuel and fuel additive under section 211(b) and 211(e) of the Clean Air Act. The requirements include subchronic inhalation testing for mortality, morbidity, general health, and unan-ticipated changes to the health of rat populations exposed to high concentrations of biodiesel exhaust. Biodiesel will be the first alternative fuel to meet these requirements. Fuels and additives that fail to meet this requirement can be illegal to sell in the United States.

Approach/Background: The National Biodie-sel Board coordinated funding of the contract and the management of this project on the behalf of biodiesel producers, the biodiesel stakeholder community, and NREL. The overall project costs are approaching $1.5 million, of which NREL contributed a small portion.

A competitive bid for project contractor was awarded to Lovelace Biomedical and Envi-ronmental Research Institute. Lovelace, the National Biodiesel Board, and the EPA negotiated the protocols of the project scope, design, and goals. That protocol was incorporated into the Lovelace contract and into the National Biodiesel Board’s contract as project manager. NREL has been apprised of progress through monthly status reports. The final report will be submitted to the EPA and will become part of the public record.

Status/Accomplishments: The project is nearly complete and is on time. A draft final report is undergoing peer review. In a few months, it will be submitted to the Environmental Protection Agency and become a public document. NREL has no plans to publish the document at this time.

Publications and Presentations: Monthly status reports

Summary Date: March 2000

Biodiesel Process Engineering and Economics

Research Funded by: U.S. Department of Energy Office of Fuels Development through the National Renewable Energy Laboratory

Project Manager: Robert Wooley 303.384.6825, Robert_Wooley@nrel.gov

Performing Organization: Proforma Systems Inc., 13902 W. 20^th Place, Golden, CO 80401

Principal Investigator: Ron Landucci, 303.278.0299, proforma@denver.net

Contract Number: TXL-9-29031-01

Contract Period:05/99-09/00

Contract Funding:

FY 1999: $39,375

Objectives:

1. to document the multiple pathways for producing biodiesel to gain a better understanding of where to target process improvements;
2. to document the cost–benefit tradeoffs of different conversion processes as a function of feedstocks and coproduct opportunities;
3. to build a stronger basis for determining biodiesel costs and potential production cost improvements; and
4. to provide future industry entrants with a basic overview of biodiesel technology.

Approach/Background: In an earlier project, NREL contracted with MARC-IV to evaluate a variety of biodiesel technologies. This cursory work provided simplistic input–output data for a variety of processes and a summary overview of the type of processes available from certain European biodiesel plants and companies. The report indicates where technologies have been patented or where information may be available in the public domain. The report contains some simplistic economic data on scale that cannot be verified. The report provides suggestions about various technological processes that may be in use, without providing enough data to evaluate the merits of the processes in a comparative manner.

NREL needs a modeling system that can represent a variety of crushing and conversion technologies for use with a variety of feedstocks, optimize processes for a specific feedstock type and slate of byproducts, and perform financial analyses for a variety of plant characteristics. When the modeling system is used with other feedstock production tools being constructed under another contract, NREL will be able to evaluate the costs and benefits of targeting specific feedstocks or conversion processes that can reduce the cost of biodiesel to the public.

Status/Accomplishments: A preliminary analy-sis of soy crushing and soy biodiesel has been prepared. Site visits are underway to further refine these and ongoing analyses of the production of biodiesel from recycled grease. A draft report is anticipated in June 2000.

Publications and Presentations: None

Summary Date: March 2000

Biodiesel Emissions from Locomotive Engines

Research Funded by: U.S. Department of Energy Office of Fuels Development through the National Renewable Energy Laboratory

Project Manager: Robert Wooley 303.384.6825, Robert_Wooley@nrel.gov

Performing Organization: Southwest Research Institute, 6220 Culebra Road, P.O. Drawer 28510, San Antonio, TX 78225-0510, http://www.swri.edu

Principal Investigator: Steve Fritz, 210.522.3645, sfritz@swri.edu

Contract Number: AXE-9-29057-01

Contract Period: 07/99–09/00

Contract Funding:

FY 1999: $83,519

Objective: Document particulate and soot reductions from blending biodiesel with diesel fuel used in locomotive engines. Data needed to perform cost benefit analysis for new market application.

Approach/Background: This research project is designed to test an in-service locomotive engine that is typical of existing rolling stock. Of the 20,000 locomotive engines in use today, roughly 1,000 are newer-model four-stroke engines in the 6,000–6,600 hp range. Of the older engines, most are 3,000–4,500 hp engines made (in roughly equal numbers) by the Electro-Motive Division of General Motors and by General Electric. All Electro-Motive Division engines are two-stroke. The larger General Electric engines are four-stroke and the smaller are two-stroke. Most urban transit and Amtrak engines are Electro-Motive Division two-stroke 4,500-hp models.

A locomotive engine will be acquired from the rolling stock through a partnership with a commercial or municipal organization. The locomotive will be driven to Southwest Research Institute’s laboratory, where it will be tested to determine its suitability for the project (e.g., all cylinders must be operational).

Biodiesel will be blended with diesel fuel, and a B20 and a B100 fuel will be tested. (The blends could be modified through mutual agreement with project partners.)

Regulated emissions will be collected and reported to the California Air Resources Board and other interested agencies or firms. A report will be prepared describing the project.

Status/Accomplishments: The project is waiting for a locomotive. Several interested potential partners have been identified.

Publications and Presentations:None

Summary Date: March 2000

Health-Related Emissions from Various Biodiesel Fuels

Research Funded by: U.S. Department of Energy Office of Fuels Development through the National Renewable Energy Laboratory

Project Manager: Robert Wooley 303.384.6825, Robert_Wooley@nrel.gov

Performing Organization: University of Iowa, 213 Beardshear Hall, Ames, IA 50011

Principal Investigator: Jon Van Gerpen, 515.294.5563, jvg@iastate.edu

Contract Number: ACG-8-17106-01

Contract Period: 10/97–09/00

Contract Funding:

FY 1998: $268,580

Objectives: Polyunsaturated fuels produced 4–15 times the NO_x emission increases produced by saturated fuel. This project examines biodiesel composition and the role it plays in NO_x emissions.

Approach/Background: For this project, 21 ethyl and methyl fatty acids (the chemical components of most biodiesel fuels) will be produced, characterized, and tested to determine how biodiesel fuel components affect NO_x emissions. A full range of petroleum and biodiesel fuel properties will be tested for each fatty acid ester. Regulated emissions data will be collected from a Detroit Diesel Corporation Series 60 diesel engine used for California Air Resources Board certification for each fatty acid ester. Using a combustion bomb, investigators will measure NO formation as a function of time in the spray, measure temperature as a function of time and position in the spray, and measure fuel-droplet size and liquid-volume fraction as a function of time and position in the spray.

This project will result in a uniform and consistent database of emissions and characteristics of different types of biodiesel and biodiesel components that will be unique. By eliminating variation due to different test equipment, engines, methodologies, and fuel qualities, potentially small differences between fuels become statistically robust.

Special testing equipment was designed, built, and validated for these purposes.

Status/Accomplishments: The project is 70% complete. A draft report has been received that describes the effect of the different fatty acid esters on U.S. Environmental Protection Agency FTP heavy-duty emissions from a Detroit Diesel Corporation Series 60. This work confirms earlier findings that saturated fatty acids all reduce NO_x. Only the unsaturated fatty acids increase NO_x. The NO_x increase is higher as levels of polyunsaturation increase. Researchers found that NO_x formation was highly correlated with iodine number, density, and cetane number, which in turn are highly correlated with the degree of unsaturation.

The combustion bomb tests are currently underway and should be completed in the spring of this year. A final report is anticipated by the end of the year.

Implications of this work include fatty acid design or blending recipes for feedstocks or for different types of biodiesel to ensure that NO_x emissions are minimized.

Publications and Presentations:

1. 2000 Biodiesel Research Brainstorming and Coordination Workshop, Phoenix, AZ . Feb. 2, 2000.
2. Effect of biodiesel composition on NO_x and PM emissions from a DDC Series 60 engine. 2000 (draft report is in peer review).
3. NREL plans to publish a series of reports on this subject.

Summary Date: March 2000