Location: Sustainable Biofuels and Co-Products
2013 Annual Report
Biodiesel is subjected to nearly 20 Official Assays to ensure its quality. For the first time a method was created to standardize the test system employed to conduct one of these assays, that for Cold Soak Filtration time (CSFT). This standardization method will give greater uniformity and reliability to CSFT data, thereby helping to ensure the in-field performance of biodiesel.
A previously developed method achieves chemical rearrangement of the fatty acids found in vegetable oils and animal fats, resulting in ‘branched’ structures that can be used to improve cosmetics, paints, and lubricants. Continuing studies have now resulted in a process for retaining/regenerating the activity of the rearrangement catalyst. This reduces catalyst use and improves the environmental friendliness of the reaction. In further work, the economic model for this fatty acid branching technique was modified to incorporate the impact of adopting the new catalyst regeneration technology. The resulting model highlighted the substantial savings that could be realized by adopting catalyst regeneration.
Derivatives of fats and oils such as phenolic-branched-chain fatty acid products are potentially useful as lubricant additives and antioxidants. Researchers developed an efficient technology to join the fatty acids found in agricultural fats and oils with phenolic compounds, and means to purify the resulting products. Methods to analyze the physical properties of these new compounds were developed. This determination of properties will facilitate the identification of applications.
To develop further outlets for the abundant glycerol co-product of biodiesel production, researchers examined the effects of infusing biobased polymers such as corn fiber gum, pectin, sugarcane bagasse and microcrystalline cellulose into gels and films produced from glycerol. The properties of the resulting hybrids make them potentially good candidates in agricultural and medicinal applications because of their abilities to absorb and desorb organic solvents.
An innovative stepwise procedure for constructing fatty acid oligomers was developed. This approach is useful for incorporating branching units, which alter lubrication and rheology properties, at selected points in the chain. Several examples were prepared, viscosities of the materials were measured, and they compare well with other known lubricants. These new bio-based lubricants were also chemically modified to make them resistant to hydrolytic degradation. Such improved stability is rare in fat-derived materials, so this procedure may open the door to utilizing bio-based lubricants in harsh environments that have previously been amenable only to petroleum products.
2. Establishing the utility of a biodiesel process coproduct. In using oilseeds for biodiesel production it is never economically sufficient to produce only biodiesel, since oil quantities are a small percentage of the oilseed and since oil value can be low. The sale of coproducts – such as the seed meal - is necessary for economic survival. Workers around the world have contributed to developing a new method of producing biodiesel, termed ‘in situ transesterification’, that simplifies the process and eliminates the toxic, air polluting organic solvents typically involved in isolating vegetable oils for biodiesel production. In the first trial of its type, ARS researchers at Wyndmoor, Pennsylvania established that the soybean meal exiting an in situ transesterification process was a suitable feed for poultry nutrition. Chickens consuming feed containing this meal had the same weight gains and feed efficiencies as birds consuming diets containing conventional oilseed meal. By establishing that the coproduct meal has a use in animal nutrition, and thus an economic value, this work could stimulate the adoption of in situ transesterification for biodiesel production. 3. Production of biodiesel from low quality lipids: There is a need to identify superior catalysts for the production of biodiesel from waste greases. Sodium methoxide, the most common catalyst for biodiesel production, is optimally effective with refined oils (e.g., soybean oil). With less homogeneous feedstocks such as waste greases its effectiveness is reduced. To address this issue, ARS researchers at Wyndmoor, Pennsylvania developed two new catalysts that are compatible with and effective on waste greases, giving biodiesel yields as high as 95%. This work can potentially reduce both the cost of and the waste streams generated by biodiesel production, thus leading to greater biodiesel availability while also improving environmental and public health.
4. Synthesis and characterization of hyperbranched polymeric gels and films based on glycerol, diacids, lignocellulosic biomass and purified plant cell wall polysaccharides: Increased production of biodiesel is accompanied by an increased supply of glycerol, the coproduct of the process. Due to the vigorous growth of the biodiesel industry the traditional markets for glycerol have been swamped and new uses are needed. ARS researchers at Wyndmoor, Pennsylvania have developed methods to synthesize new polymers from glycerol. These have now been amended with lignocellulosic biomass and purified plant cell wall polysaccharides, and the resulting products assessed for potential uses as absorbent gels, plastics, additives, lubricants, pH- and temperature-sensitive polymers, and conductive polymers. The use of glycerol in these new sectors would increase its consumption, and thereby have a significant positive impact on the overall economics of biodiesel production,
Ngo, H., Dunn, R.O., Hoh, E. 2013. C18-unsaturated branched-chain fatty acid isomers: characterization and physical properties. European Journal of Science and Lipid Technology. 115:676-683.
Wyatt, V.T., Yadav, M.P., Latona, N.P., Liu, C. 2013. Thermal and mechanical properties of glycerol-based polymer films infused with plant cell wall polysaccharides. Journal of Biobased Materials and Bioenergy. 7:348-356.
Ngo, H., Vanselous, H.N., Strahan, G.D., Haas, M.J. 2013. Esterification and Transesterification of greases to fatty acid methyl esters with highly active diphenylamine salts. Journal of the American Oil Chemists' Society. 90:563-570.