Location: Bio-oils Research
2021 Annual Report
Objectives
Objective 1. Resolving processing technologies to convert low-quality and nonfood feedstocks into value-added biobased products.
Sub-objective 1.A. Develop low-quality (vegetable oil refining wastes, used cooking oils and greases and residual oils from ethanol fermentation) and nonfood feedstocks for conversion to biodiesel and biobased products. Resolve pretreatment processes and eliminate (or minimize) needs for chemical preparation of low-quality and nonfood (LQNF) feedstocks.
Sub-objective 1.B. Resolve final process technologies for converting low-quality and nonfood (LQNF) feedstocks to biodiesel and value-added coproducts.
Objective 2. Enable commercial processing of new versatile biobased products useful in multiple markets.
Sub-objective 2.A. Enable novel and cost-competitive biobased products with unique structures for applications in multiple industrial sectors.
Sub-objective 2.B. Investigate functional property of novel biobased structures for lubrication, remediation, surfactant/detergent, polymers and other applications; apply structure-property models to optimize the chemical structures for multi-functional application.
This project is aimed at enabling new commercial technologies, processes, and multi-functional biobased products applicable in multiple markets without further modification or processing. Where applicable, low-cost feedstocks from cheap process waste streams will be used. Developed products will have applications in environmental remediation, household and industrial surfactants and detergents, lubricant base oils and additives, cleaners and solvents, polymers and plasticizers, and biofuels and biofuel additives. The technologies and products from this research will be competitive in cost and performance to those currently in the marketplace. The biobased products targeted in this project will result in significant improvements to the U.S. agricultural economy and the environment as well as to the safety and health of the American people.
Approach
Biofuels and biobased products are essential for maintaining a sustainable bioeconomy, protecting the environment, and enhancing the health and safety of citizens. Their widespread application requires efficient and cost-effective processing of farm-based raw materials. Achieving this goal will require overcoming complex technological hurdles to reduce manufacturing costs and expand their ranges of application. This research plan will develop technology for the conversion of low-cost ag-based raw materials to biodiesel and value-added bioproducts with applications in multiple markets. Bioproducts from this research will be developed with potential applications in the environmental remediation of heavy metals from waste streams, household and industrial cleaners, surfactants and detergents, biobased lubricant additives and base oils, fire-resistant polymers and plasticizers, and biodiesel and biodiesel additives. This research project is organized in two main objectives.
Objective one is tasked with the goals of expanding the feedstock supply for conversion to biodiesel and developing alternate conversion processes that produce biodiesel with enhanced cold flow properties. Sub-objective 1.A will expand the feedstock by the development of cost-effective pretreatment processes for upgrading low-quality oils and free fatty acids (FFA) obtained from vegetable oil refining wastes, used cooking oils and greases, and sorghum distiller’s dried grain with solubles (DDGS). Sub-objective 1.B will develop alternative processes for converting low-quality and nonfood (LQNF) feedstocks to biodiesel with improved cold flow properties. These processes will be designed to yield biodiesel mixed with co-products in one conversion step where the co-products can act as built-in cold flow improvers.
Objective two is tasked with the development of multi-functional biobased products from waste cooking oil (WCO) and other low-cost feedstocks. The biobased products will have versatile structures that will allow them to perform in multiple application sectors. Sub-objective 2.A will enable the synthesis of cost-competitive biobased products such as phosphonates, thiophosphates, disulfides, gemini surfactants and polyurethanes (PU). Sub-objective 2B will enable the characterization of these materials in multiple application sectors such as lubrication, environmental remediation, surfactants, detergents and polymers. Structure-property models will be applied to allow for the synthesis of optimized structures of multi-functional biobased products.
Progress Report
The development of alternative feedstock oil originating from agricultural products and residues is important to the advancement of renewable biodiesel and biobased products in the near and distant future.
Objective 1.A: Samples of low-erucic acid pennycress oil and residual oil from corn fermentation were acquired for study. Membranes to separate oils and waxes from feedstocks were selected and experimental conditions identified in bench-scale screening studies for pretreating the low-quality nonfood oils.
Objective 1.B: Efficient catalysts for synthesis of performance enhancing biodiesel fuel additives were selected. Separation methods for isolating and enriching synthesized products were identified.
The properties of biodiesel will affect its quality and performance as a commercial fuel. We analyzed the fuel properties of canola, palm, and soybean oil biodiesel fuels. The results yielded reference data for use in predictive models to identify and test new nonfood oil feedstocks.
Objective 2.A: We elucidated the factors affecting the formation of acids during the synthesis of biobased phosphonates. Biobased phosphonates synthesized from vegetable oils have shown promise as lubricants and lubricant additives. Acids formed during the synthesis must be removed for the product to be acceptable for lubrication applications. The results showed that acid contents increased at higher reaction temperatures. Avoiding acid formation during the synthesis reduces the need for washing and drying of the product, which simplifies and reduces the costs of the production process.
Objective 2.B: We conducted a literature search on ‘multi-functional’ biobased products. Multi-functional biobased products have physical properties that allow them to be used in many applications. We used the literature search results to write a review book chapter on the use of biobased phosphonates as multi-functional lubricant additives and submitted it to the American Chemical Society Books. The book chapter will increase visibility and use of biobased phosphonates.
Accomplishments
1. Predicting shelf life of biodiesel. Biodiesel can lose some of its fuel quality when stored at warm temperatures (25 deg. C) for long time periods. The problem arises from air reacting with biodiesel to shorten its shelf life. ARS researchers at Peoria, Illinois, developed a method to assess the shelf life of biodiesel at 25 deg. C. This method analyzes biodiesel using pressurized differential scanning calorimetry to determine the rate of oxidation under different conditions. We used these results to develop predictive models to calculate the shelf life of biodiesel at low temperatures. These models will benefit biodiesel fuel producers, terminal operators, and other users who need to store biodiesel in warm weather.
2. Best model selected to predict viscosity/temperature relationships. Estolides, a class of lipids that can be made from vegetable oil, were recently added to the market where they serve as renewable biolubricants. To widen their adoption as lubricants, their viscosity (resistance to flow) needs to be within tight specifications. ARS researchers at Peoria, Illinois, measured the viscosity of estolides made from oleic acid (a common component in vegetable oils) at different temperatures and compared the data with several previously reported theoretical models. The best of the models predicted well the measured viscosity data from the size of the estolides, which can be easily manipulated. These results will allow tailoring the estolide size to achieve the viscosity needed for specific applications. This will allow agricultural-product-based estolides to be used as engine oils, hydraulic fluids, and metalworking fluids.
3. Biodiesel from modified pennycress oil. There is a need for new feedstocks for production of biodiesel and other biobased materials. Oils from traditional field pennycress represent an opportunity to enhance biodiesel production. However, these oils have high concentrations of erucic acid which can adversely affect the fuel properties of biodiesel. Recently, ARS researchers at Peoria, Illinois, produced biodiesel from a new low-erucic acid pennycress (LEAP) oil and tested its fuel properties. This biodiesel showed improvements in fuel properties such as viscosity (resistance to flow) and flow at low temperatures compared to biodiesel from traditional pennycress oil. This work advances the goals of increasing biodiesel production by identifying new crop feedstocks that yield biodiesel with good fuel quality.
Review Publications
Biresaw, G., Bantchev, G.B., Harry-O'kuru, R.E. 2020. Phosphonates of vegetable oils – Characterization as lubricants. Journal of the American Oil Chemists' Society. 98(1):89-102. https://doi.org/10.1002/aocs.12448.
Hay, W.T., McCormick, S.P., Hojilla-Evangelista, M.P., Bowman, M.J., Dunn, R.O., Teresi, J.M., Berhow, M.A., Vaughan, M.M. 2020. Changes in wheat nutritional content at elevated [CO2] alter Fusarium graminearum growth and mycotoxin production on grain. Journal of Agricultural and Food Chemistry. 68(23):6297-6307. https://doi.org/10.1021/acs.jafc.0c01308.
Dunn, R.O. 2021. Correlating the cloud point of biodiesel with its fatty acid methyl ester composition: Multiple regression analyses and the weighted saturation factor (wSF). Fuel. 300. Article 120820. https://doi.org/10.1016/j.fuel.2021.120820.
Dunn, R.O. 2021. Oxidation kinetics of biodiesel by non-isothermal pressurized-differential scanning calorimetry. Transactions of the ASABE. 63(3):687-701. https://doi.org/10.13031/trans.13708.
Isah, S., Zhang, J., Biresaw, G., Strahan, G.D., Nunez, A., Wyatt, V.T., Ngo, H, Ozbay, G. 2021. Synthesis of Dimer Acid 2-Ethylhexyl Esters and their Physicochemical Properties as Biolubricant Base Stock and their Potential as Additive in Commercial Base Oils. Journal of the American Oil Chemists' Society. 98(6):683–695. https://doi.org/10.1002/aocs.12455.
