Location: Bio-oils Research2012 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 and contaminants on biodiesel fuel properties such as oxidative stability and cold flow behavior were investigated. Numerous alternative feedstocks for biodiesel with the goal of increasing biodiesel supply were researched including those with alternative fatty acid profiles for improving biodiesel fuel properties. Other feedstocks were evaluated for potential properties. The results also aid in establishing structure-property relationships for biodiesel components. Additives to improve oxidative stability, for which gossypol is promising, and cold flow of biodiesel were prepared and tested. Seventeen collaborations with various universities (Clemson; Iowa State; Oklahoma State; Western Washington; Universidade Federal de Vicosa, Vicosa, Brazil; University of Delaware; University of Idaho; Universiti Putra Malaysia; University of Nevada-Reno) and institutions (Argonne National Laboratory, Argonne, IL; Atlantic Greenfuels, Beachwood, OH; Illinois Sustainable Technology Center, Urbana-Champaign, IL; LubriGreen, Irvine, CA; National Renewable Energy Laboratory, Golden, CO; Sandia National Laboratory, Livermore, CA; Southwest Research Institute, San Antonio, TX; and Woods Hole Oceanograpic Institution, Woods Hole, MA) leading to research results on combustion, fuel properties, and fuel composition that were incorporated in publications or will be used in pending publications and for supporting on-going research as well as 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.
1. Biodiesel from alternative 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 for improvement of current production procedures is critical. Scientists in the Bio-Oils Research Unit at the USDA-ARS National Center for Agricultural Utilization Research (NCAUR), Peoria, IL, investigated several oils for biodiesel applications which included anise, arugula, avocado, black currant, borage, castor, corn distillers’ grains with solubles, hazelnut, high-oleic peanut, lesquerella, olive, upland cress, and walnut. Based on fuel property data obtained from biodiesel prepared from these oils, along with others investigated previously, a practical screening matrix was developed that was based on fatty acid profile. Feedstocks high in monounsaturated fatty acid content and with low levels of long-chain saturated and polyunsaturated fatty acids were recommended for further evaluation as sources of biodiesel. Overall, such work will contribute to enhancing the supply of biodiesel and reduce dependence on petroleum-based diesel fuel by lowering the cost of biodiesel production, thereby improving process economics.
2. Biodiesel with improved oxidative stability. A significant technical deficiency of biodiesel is reduced storage stability relative to conventional petroleum diesel fuel. Scientists in the Bio-Oils Research Unit at the USDA-ARS National Center for Agricultural Utilization Research (NCAUR), Peoria, IL, investigated naturally-derived additives as a means to enhance fuel properties of biodiesel. Gossypol is a readily-available toxic component of cottonseed oil and meal with polyphenolic functionalities. Thus, it must be removed before the oil or meal may be used in food applications. Addition of gossypol to biodiesel resulted in a significant improvement in storage stability that was comparable to commercially-available synthetic antioxidants. This research demonstrated that a by-product of cottonseed production has added value as a powerful bio-based antioxidant additive for biodiesel, and will contribute to the development of technologies to improve biodiesel's resistance to degradation during storage.
3. Cold flow properties of biodiesel. Blends of petrodiesel with biodiesel can be problematic during cold weather. ARS scientists in the Bio-Oils Research Unit at the USDA-ARS National Center for Agricultural Utilization Research (NCAUR), Peoria, IL, evaluated the crystallization behavior of simulated biodiesel mixtures at low temperatures to identify optimum compositions that prevent cold flow problems. Crystallizations were carried out for mixtures of two different high-melting point methyl esters and one low-melting point methyl ester, showing that specific component mixtures of biodiesel can optimize low temperature operability. These results will lead to methyl ester compositions to improve cold flow properties and performance of biodiesel from commodity oil and alternative lipid feedstocks.
Joshi, H., Moser, B.R., Walker, T. 2012. Mixed alkyl esters from cottonseed oil: Improved biodiesel properties and blends with ultra-low sulfur diesel fuel. Journal of the American Oil Chemists' Society. 89(1):145-153.