Location: Bio-oils Research2011 Annual Report
1a. Objectives (from AD-416)
Improve the fuel properties and performance of vegetable oils and their derivatives as alternative fuels, extenders, and additives in the operation of compression-ignition (diesel) engines for on-road and off-road applications. Address technical problems identified by stakeholders and customers. Specific objectives for this project are: 1) Enable new commercially-viable alternative fuel formulations with improved cold weather start-up and operability performance without compromising fuel quality as defined by appropriate standard fuel specifications; 2) Enable new commercially-viable biodiesel formulations with improved storage stability with respect to oxidative degradation. Develop rapid measurement methods for monitoring effects of degradation on biodiesel fuel quality during storage, as defined by appropriate standard fuel specifications; 3) Enable new, commercially-viable biodiesel fuels derived from novel oilseed crops (especially inedible plant species), vegetable oils with modified fatty ester composition, and non-traditional feedstocks such as algae and biomass; 4) Enable new, commercially-viable analytical methods for biodiesel and its minor constituents and other fuel quality issues to enhance market acceptance of biodiesel fuels; and 5) Develop technologies that expand the markets for glycerol by enabling the commercial conversion of glycerol and its derivatives to chemicals and components in products such as surfactants, emulsifiers, fuel additives, dispersants and/or flocculating agents as well as biodegradable polymer products such as polyesters, polyethers and polyurethanes.
1b. Approach (from AD-416)
Biodiesel is an alternative diesel fuel derived from vegetable oils, animal fats, used oils or algae, and other biomass feedstocks. While it is competitive with (in some aspects even technically superior to) petroleum-derived diesel fuel, its use is still affected by technical and supply issues that hinder more widespread commercialization. This project proposes to improve the fuel properties of vegetable oils as well as other feedstocks and their derivatives as alternative diesel fuels, extenders, and additives in the operation of compression-ignition (diesel) engines for on-road and off-road applications. Specific objectives for this project include: 1) Improve cold weather start-up and operability; 2) Enhance understanding of oxidative stability and provide methods for its improvement; 3) Provide novel fuel formulations, including alternative and conventional feedstocks with different fatty acid profiles as well as novel additives; 4) Develop analytical methods for minor constituents of biodiesel and other fuel quality issues; and 5) Development of specialty chemicals and products such as biodegradable polymers from biodiesel co-products (glycerol). Overall, this research will lead to technically improved biodiesel fuels that are more competitive in the marketplace, enhanced analyses, and new, economically competitive and environmentally friendly products from glycerol.
3. Progress Report
The effects of small concentrations of minor constituents (monoglycerides) on fuel properties and cold flow performance of biodiesel were studied. Correlations for predicting volumetric percent of biodiesel in blends with petrodiesel for use in the field were developed. Correlations converting between mass and volumes of fuel blends (that is, density/gravity of blends) for blends of soybean oil and used cooking oil biodiesel and ultra-low sulfur petrodiesel were developed. Alternative feedstocks for biodiesel with the goal of increasing biodiesel supply were investigated as were feedstocks with alternative fatty acid composition for improvement of biodiesel fuel properties. Other feedstocks were evaluated for potential performance. Structure-property relationships for biodiesel components were established. Additives for biodiesel to improve cold flow and oxidative stability were prepared and tested. Fourteen collaborations with various universities (Clemson, Iowa State, Oklahoma State, Western Washington Universities, University of Delaware, University of Idaho, University of Illinois-Urbana, and Universiti Technologi Petronas, Malaysia) and institutions (Atlantic Greenfuels, Beachwood, OH, Carner Renewable Energy Sources, Chicago, IL, Illinois Sustainable Technology Center, Urbana-Champaign, IL, Sandia National Laboratory, Livermore, CA, Southwest Research Institute, San Antonio, TX, and Woods Hole Oceanographic Institution, Woods Hole, MA) on combustion, fuel properties, fuel composition, and biodiesel education. Collaborated with the Agricultural Research Service Eastern Regional Research Center on synthesis and testing of new cold flow additives for biodiesel and biolubricants. Collaborated on developing a Cooperative Research and Development Agreement (CRADA) with an industrial partner to develop biodiesel as fuel in lean-burning engines with plasma-injection systems.
1. Thermal-oxidative stability of biodiesel. Degradation during storage can reduce the performance of biodiesel in diesel engines. ARS Bio-Oils Research Unit scientists at the National Center for Agricultural Utilization Research (NCAUR), Peoria, IL, performed studies on thermal and oxidative degradation of biodiesel made from soybean, palm, rapeseed, and used cooking oils. Biodiesel was tested at high pressures and temperatures in the presence of gases (air and oxygen) that cause decomposition and a gas (nitrogen) that does not cause decomposition. Results showed that gas composition affects the overall degradation process and the temperature where biodiesel begins to degrade. This work contributes to the development of technologies to improve biodiesel's resistance to degradation and to accurately monitor the fuel quality of biodiesel during storage.
2. Biodiesel with improved properties and/or from alternative oilseed feedstocks. Due to the limited supply of commodity vegetable oils available for biodiesel production, the search for additional oils or fats that can serve as feedstocks or improvement of current production procedures is critical. Oils that were successfully evaluated by ARS Bio-Oils Research Unit scientists at the National Center for Agricultural Utilization Research (NCAUR), Peoria, IL, for biodiesel applications included black locust, black mulberry, crepe myrtle, cuphea, Osage orange, seashore mallow, shepherd’s purse, and spent coffee grounds. Biodiesel from cuphea enriched in a shorter-chain fatty acid showed improved performance (better burning, less problems in cold weather, less degradation) in an engine, to a large extent similar to that of diesel fuel from petroleum. Such oils can be used as alternative biodiesel feedstocks that do not displace existing agricultural production. Because some technical problems remain with biodiesel, fuel properties continue to be investigated. Overall, such work will contribute to making more biodiesel with better properties available and reduce dependence on petroleum-based diesel fuel.Dunn, R.O. 2011. Specific gravity and API gravity of biodiesel and ultra-low sulfur diesel (ULSD) blends. Transactions of the American Society of Agricultural and Biological Engineers. 54(2):571-579.