1a. Objectives (from AD-416)
Objective 1: [addresses NP 307 Action Plan Problem Statements 3(c)(1), 3(c)(2) and 3(a)(4)] Develop new technologies that enable (1) commercial direct (‘in-situ’) production of biodiesel, and (2) commercially-preferred processes for the production of biodiesel from available, low-cost feedstocks. Objective 2: [addresses NP 307 Problem Statements 3(c)(1), 3(c)(2) and 3(a)(4)] Develop technologies that enable commercially-preferred technologies to remove performance-degrading biodiesel contaminants such as catalysts, sterol glucosides and sulfur. Objective 3: [addresses NP 307 Problem Statement 3(c)(5), and NP 306 Problem Statement 2c] Develop technologies that enable; (1) commercial production of hyperbranched polymer products from byproduct glycerol; and (2) commercially-viable and environmentally benign processes for new high-value industrial products made from fatty acids or the combination of fatty acids and lignin derivatives.
1b. Approach (from AD-416)
Develop technologies to use heterogenous catalysts to replace homogenous catalysts in the synthesis of biodiesel from free fatty acids and from glycerides in low quality feedstocks. Improve and scale-up methods newly develop method for biodiesel synthesis from trap grease. Using chromatographic and spectroscopic technologies, identify the structures of sulfur containing species contaminating biodiesel from low quality feedstocks and develop methods for their removal. Using enzymatic catalysis, remove sterol glucoside contaminants from vegetable oil based biodiesels. Develop new methods for the use of novel solid catalysts to modify fatty acids, in some cases through their combination with lignin degradation products generated by the pyroloysis of lignocellulosic feedstocks, to produce lubricants, personal care materials, and other functional lipids. Develop organic chemical methods to produce prepolymers from biodiesel glycerol and organic di-acids and use these to produce hyper-branched polymers. Determine the size and structures of these and determine their physical properties.
3. Progress Report
In the development of new technologies for biodiesel production (Obj. 1), new approaches were investigated for the use of algal biomass, distillers dried grains with solubles, and trap grease as feedstocks, with substantial progress on especially the algal and trap grease materials. Collaborative work on the latter feedstock assisted in maturation of a private sector field demo site, substantially advancing product quality and throughput. Collaborations were formed to facilitate field pilot testing of new biodiesel production technologies developed in this project. In extensions and refinements of efforts to develop solid state catalysts for biodiesel production (Obj. 2-1) researchers improved their previously-developed synthetic route by developing a more affordable catalyst system to efficiently convert low quality, affordable waste materials to biodiesel. In efforts to produce high quality biodiesel from the affordable but extremely low quality feedstock trap grease, very substantial advances were made in developing effective and affordable technologies for removing sulfur species from the product (Obj. 2-3), allowing it to meet official specifications for sulfur content. In the synthesis of highly branched oligomers and polymers from glycerol and organic diacids (Obj. 3-1), significant efforts were invested in determination of the size and degrees of branching of the products, in the development of product purification protocols, and in development of methods for determination of the residual levels of unreacted starting material in the product polymers. Optimization of reaction conditions for the synthesis of hyperbranched polymers achieved a very desirable 70% reduction in the volume of organic solvent used in the process. Project researchers have identified methods that link the components of vegetable oils into well-defined short polymers that are expected to have lubricant properties (Obj. 3-2a). Using this methodology, different structures can be prepared from the fatty acid starting materials. These are then subjected to direct comparisons with one another to determine which molecular shapes lead to better lubrication. A variation on this methodology allows construction of fat-derived chains that should be resistant to hydrolysis, making them more useful in harsher environments. Construction of these compounds and testing of their lubricant properties is ongoing. As a component of Objective 3-2b (new materials from the combination of fatty acids and lignin derivatives) an efficient approach to produce a new biobased product (i.e., hydroxyl-aryl-branched-chain fatty acid isomers) by combining conventional fats and oils with pyrolysis-derived oil has been developed. The reaction conditions were optimized and high yields of the desired product were obtained. In ongoing studies, the physical properties of the materials are being determined, with an eye toward impacts on freezing and melting points, high temperature stability, and antioxidant properties.
1. New energy life-cycle analysis of soybean biodiesel. A quantitative assessment and comparison of benefits is fundamental to determining whether a biobased technology offers advantages relative to an existing petroleum-based analog. To compare soybean oil-derived biodiesel fuel with conventional petroleum diesel fuel, such a ‘life cycle’ assessment of net energy yield was published in 1998, based largely on pre-1990 data. In the interim there has been profound technological evolution in this sector. Thus, in the current effort, ARS researchers and engineers at Wyndmoor, PA, in collaboration with investigators at the University of Idaho and the USDA Office of the Chief Economist, repeated the analysis using more contemporary (2006) agricultural and technological data and new modeling inputs. This more contemporary and accurate assessment concluded that soybean biodiesel yields 5.54 units of energy per unit of invested fossil energy, substantially larger than the 3.2 figure previously calculated, and substantially greater than the value for petroleum based diesel fuel, which is less than 1. This recently published information more accurately describes the energy yield of biodiesel, greatly facilitating technical as well as policy discussions (setting levels of Advanced Biofuels by EPA for RFS2) regarding this alternate to petroleum-based diesel fuel. The work was covered by a press release carried in numerous US and International media reports.
2. Environmentally friendly and sustainable means of producing biodiesel from trap greases. The current technologies for biodiesel production using refined vegetable oil as feedstock are not cost-competitive to petrodiesel in the absence of federal subsidies. In collaboration with a university partner, ARS researches at Wyndmoor, PA, developed a new catalytic route that can efficiently convert very low quality feedstocks (i.e., trap greases) to biodiesel. The improved process does not use refined and expensive feedstocks, and therefore does not compete with food crops. The biodiesel products from this process do not require extensive washing with water for cleanup. This process is thus potentially more environmentally friendly and sustainable.
3. Advanced new means to generate polymers from glycerol. Increased production of biodiesel has generated excessive quantities of the byproduct glycerol. The development of new uses for glycerol would increase the economic strength of the biodiesel industry by creating new market outlets for glycerol. ARS researchers at Wyndmoor, PA, invented ways to synthesize glycerol-based polymers. Here, the utility of adding a background solvent to the synthetic reaction was investigated. Experimental conditions such as temperature, molar ratio, and reaction times were studied to create a family of glycerol-based polymers with varying thermal, physical and mechanical properties. These are being investigated for potential uses as absorbent gels, plastics, additives, lubricants, pH- and temperature-sensitive polymers, and conductive polymers. The development of new uses and markets for glycerol would have a significant positive impact on the economics of biodiesel production, strengthening the industry and contributing to the desirable elimination of governmental subsidy support for this biofuel.Wyatt, V.T., Nunez, A., Strahan, G.D. 2010. The Lewis acid catalyzed synthesis of hyperbranched Oligo(glycerol-diacid)s in aprotic polar media. Journal of the American Oil Chemists' Society. 87:1359-1369.