Waste Cooking Oil-to-Biodiesel Conversion for Institutional Vehicular Applications.

摘要

iodiesel is a renewable, sustainable, clean-burning biogenic fuel that can serve as a substitute for conventional ultra-low sulfur diesel (ULSD). Biodiesel is comprised of mono-alkyl esters of long chain fatty acids and is produced via transesterification, whereby glycerin is separated from the fatty acid component of either an oil or fat. The full process yields the fatty acid methyl ester (biodiesel fuel) and glycerin, an economically valuable by-product.;As part of a United States Environmental Protection Agency (EPA) Climate Showcase Communities Grant to Monroe County, New York and Rochester Institute of Technology (RIT), the Golisano Institute for Sustainability (GIS) was engaged to develop a closed-loop biodiesel production process system using the food service waste cooking oil stocks. Because the waste oil feedstock supply and fuel demand are internal within the institution, the system dynamics, economic feasibility, and environmental benefits versus the incumbent ultra-low sulfur diesel can be effectively quantified.;Along with establishing quantitative metrics associated with quality of the fuel itself, the main goal of this part of a broader research program included utilizing the biodiesel fuel for campus vehicular applications. Ultimately, developing a robust waste-to-energy process within the system boundaries of the institution is the desired outcome, along with economic valuation, emissions testing, fuel quality metrics and standardization, life cycle assessment, and energy return on investment for the university's stakeholders.;Through the execution of this project, two successful biodiesel batches were produced which met American Society of Testing and Materials (ASTM) quality standards for vehicle use. Lower heating value (LHV) measurement demonstrated comparable embodied energy content to earlier published data. In addition, cloud point measurements were taken to understand the performance of the fuel in cold weather conditions, and these metrics were also consistent with published data for biodiesel fuels. Through direct measurements of exhaust gas composition, overall reductions in greenhouse gas emissions were observed in two test vehicles. However, consistent with published data, there is evidence that emissions of nitrous oxides (NOx) may be higher with a 20% biodiesel blend (B20), depending on the specific vehicle and the type of exhaust gas recirculation (EGR) valve technology employed.;According to a life cycle assessment conducted on the closed-loop biodiesel production process, the cumulative energy demand (CED) was 752 MJ/100 km and the global warming potential (GWP) was 80.6 kg CO2-eq./100 km. Crude oil-based diesel contributes the most to the energy and environmental impact to the total combustion CED and GWP of a B20 fuel mixture, while the methanol component contributes the greatest energy and environmental impact to just the biodiesel component. The energy return on investment (EROI) was determined to vary depending on specific waste oil properties and processing conditions, with a value of 4.16 determined to be most representative of the developed conversion process. This demonstrates that waste cooking oil biodiesel production at RIT is net energy positive, and thus can reasonably contribute to the University's renewable energy and GHG emissions reduction goals. The closed-loop biodiesel process also presented a compelling economic case, with a total computed cost of