This SBIR Phase I project will employ ethyl ethoxybutyrate as a fuel source and to determine the potential impact of this chemical on the environment. The fuel source uses low value renewable feedstock and a mixed culture of bacteria to supply the reactants. The oxygen content in the fuel makes it competitive with ethanol. The project will outline the quantitative analysis of combustion properties using a dynamometer and exhaust emission analysis. In addition, the impact this chemical has on the environment will be analyzed. The data will be used to estimate its persistence and fate in the environment.
The broader/commercial impact of the project will be to use low value materials from a wastewater treatment plant and agricultural bio-solids as a potential source of chemical feedstocks. This in turn, decreases solid waste from a wastewater treatment plant and agricultural operations.
Our NSF SBIR Phase I project had two objectives, i) validate ethyl ethoxybutyrate (EEB) as a fuel and ii) determine physiochemical and environmental characteristics of EEB. Engine tests were performed at Oak Ridge National Laboratory's Fuels, Engines, and Emissions Research Center (FEERC). The engine test results indicated that EEB provides an entry to the diesel market that ethanol suppliers currently do not have. EEB-gasoline blends were tested in a 2007 Pontiac Solstice that was operated on a dynamometer at the FEERC with the Federal Test Procedure 75 test cycle. The fuel economy and emissions for EEB-gasoline blends were similar to the ethanol-gasoline blends. Carbon monoxide levels were higher than baseline gasoline with the 20% blend, however carbon monoxide emissions for the 20% EEB-gasloline blend were still a factor of three less than the ultra-low emission vehicle (ULEV) standard for light-duty vehicles. Combustion properties were determined with standard methods and regression analysis. EEB-diesel blends up to 30% v/v met the cetane specification for on-road diesel fuel. The octane numbers were high and similar for 5% and 20% EEB-gasoline blends. Of note, the 20% EEB-gasline vapor pressure was 7 psi and met summertime gasoline formulation specifications (maximum 7 psi). Thus, the NSF SBIR Phase I Objective 1 results were very positive and indicated that EEB may be a viable diesel oxygenate and an alternative to ethanol for summertime gasoline blends. The physiochemical experimental results indicated that EEB was likely a "drop in" fuel and much more compatible with the fuel distribution infrastructure than ethanol, although additional testing for materials compatibility is required to understand how EEB blended fuels interact with fuel lines, pump hoses, and storage tanks. The melting point of EEB was lower than -70 oC indicating that EEB may be a suitable additive to biodiesel in cold climates. Multimedia assessment of EEB incubated with sediment and water suggested that EEB is susceptible to biological degradation. EEB hydrolysis data collected during sediment-water incubation experiments and data from both the EPA and OECD environmental multimedia chemical fate and persistence modeling packages suggested that EEB does not persist in the environment. Thus, the SBIR Phase I Objective 2 results were also very positive. The NSF SBIR Phase I findings support further development of EEB as a biofuel, and our NSF SBIR Phase II application objectives are to develop a prototype system suitable for production of EEB and to collect process data with the prototype system.
