Progress 06/01/08 to 05/31/09
Outputs
OUTPUTS: The goal of Phase I was to evaluate the optimum process conditions for biodiesel production using the solid catalysts copper (II) oxide (CuO), titanium (II) oxide (TiO), and manganese (II) oxide (MnO) and to determine their viability to produce ASTM quality biodiesel from a variety of low-grade feedstocks. The specific objectives of the research were to 1. investigate catalyst effectiveness for esterification of free fatty acids (FFA), 2. investigate effect of water content in feedstock on yield and quality, 3. conduct catalyst longevity trials with low-grade feedstocks, and 4. assess technologies ability to meet quality specifications for biodiesel and glycerol. Our experimental approach was to identify operating conditions to guarantee quality on spec fuel. The ability to convert tri, di, and monoglycerides as well as free fatty acids (FFA) into fatty acid methyl esters (FAME) is a primary condition for successful commercialization. Present ASTM biodiesel standards for two critical parameters are less than 0.24 wt% total glycerin and less than 0.5 acid value. A bench-scale continuous reactor was set up to extensively test the candidate metal oxide catalysts and the alternative feedstock preparations. The test results provided essential data for catalyst optimization and the design of a commercial reactor for robust feedstock processing. Tests were conducted to determine the conversion of FFA at various concentrations. While batch tests showed complete conversion of free fatty acids, these experiments detailed each catalyst's ability to handle multiple alternative feedstocks and speak to the lives of the catalysts. The maximum conversion attainable (and residual FFA in product) was assessed. Feedstock water content was tested as it is problematic for conventional processors because it can create FFA through hydrolysis of oil and cause soap formation. Various grades of wet reactants were run to assess the processes' tolerance of water on the front end and gather data on whether the catalysts remain truly insoluble. These low-grade feedstocks contain moisture and impurities with the most potential to cause loss of catalyst activity. As recommended by the National Renewable Energy Laboratory (NREL) in 2004, heterogeneous catalysts are needed to more readily meet ASTM specifications for biodiesel quality and to create a higher value glycerol co-product. Indicators of the quality of both these products must be assessed for this technology to be deemed viable. Results from this research were presented to existing small-scale biodiesel producers at the 2008 Collective Biodiesel Conference in Golden, CO. PARTICIPANTS: The research team consisted of the following individuals: Kevin Gombotz served as the Principal Investigator leading the research efforts. He was responsible for be supervising the technical director and coordinating the project consultants. He served as the key contact for all communications and will be the principle author on associated reports. Dr. Jack V. Matson was the inventor and consulting engineer working on the project and worked closely with other staff on the project to solve critical engineering problems associated with the research. Mr. Greg Austic served as the technical director for the project. He worked closely with Mr. Gombotz, Dr. Matson and the consultants to design and optimize the laboratory procedures and analyze laboratory data. He also operated the reactor and conducted analytical work designated in the work plan. Dr. Francis X. Higdon was the project manager assisting with budget tracking, equipment procurement, and project logistics. Dr. Dheeban Kannan assisted in operating the bench-scale reactor in the laboratory and conducting data analysis. Matson and Associates worked with two consultant groups throughout the duration of Phase I. Piedmont Biofuels provided analytical expertise and oversight as well as heterogeneous catalyst development experience. Dr. Yongsheng Chen provided catalyst characterization and research method expertise. TARGET AUDIENCES: The major benefit of the Matson Biofuels technology is its potential for expanding the use of agricultural feedstocks for biodiesel production in the U.S. and the impact of those expanding feedstock markets in rural communities. Higher production of biodiesel is necessary in order for there to be a major shift in the energy balance within the American economy. One of the concerns regarding the recent rapid expansion of the biodiesel industry is the use of 100 year old transesterfication chemistry to build larger and larger biodiesel plants. As feedstock prices rise due to increasing demand, these plants will become competitive relative to newer plants using more advanced, solid catalyst technology. This research will give U.S. biodiesel producers another more sophisticated processing option to draw from as they establish or expand their operations. Despite the many potential advantages using biodiesel, there are serious limits on the availability and volume of oil feedstocks needed to supply current the demand for diesel fuel. The biodiesel industry needs process technology capable of converting every available and potential oil feedstock into ASTM standard fuel in the most cost effective and environmentally sustainable way possible. The Matson Biofuels technology has the ability to impact many market segments throughout the biodiesel industry, including large and small fixed biodiesel production facilities or mobile processors. The biodiesel industry needs cheaper feedstocks, higher value products, and better yields in order to become financially sustainable. This technology uses novel long-life catalysts to process low-grade discounted feedstocks including yellow grease and tallow. Because the solid catalysts do not form soap, the glycerol co-product is of much higher value. Additionally, the Matson process projects yields 5-10% higher than with conventional technology. The process has application to small producers who are looking to avoid the handling issues of hazardous liquid acid and base catalysts while still processing varied feedstocks. A presentation, including results from this research, was given to existing small-scale biodiesel producers at the 2008 Collective Biodiesel Conference in Golden, CO. Large-scale producers stand to benefit from this technology due to increase yields and the production of a commodity value glycerol product. This research has the potential to impact all U.S. citizens. National security remains a major reason for the development of biofuels as dependence on foreign fossil fuel resources compromises U.S. security interests. Renewable fuels reduce our dependence, and offer opportunities to develop domestic resources in a cost effective manner. The expansion of biodiesel and ethanol production in the U.S. could help solve multiple economic problems such as creating new markets for American farmers, and generating economic returns from materials currently entering our waste stream. Among the many renewable fuels currently available around the world, biodiesel offers an immediate impact in our energy markets. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Our Phase I research has demonstrated that: 1. MnO and TiO are robust at both transesterification and esterification 2. The presence of water can aid glyceride conversion depending on concentration 3. The catalysts exhibit long life with little loss of activity 4. The catalysts exhibit slight leaching, but within tolerable levels 5. High quality fuel and glycerin were produced at near 99% yield. A variety of real world feedstocks were tested (yellow grease from 0 - 30% FFA) along with virgin oil doped with oleic acid (0 - 50% FFA). Higher FFA feedstocks showed much faster and more complete conversion but tended to have very high acid value, while virgin feedstock tended to be slow to convert, but had much lower acid value. The fuel acid value was significantly influenced by the presence of water, the removal of which was important to achieving ASTM quality fuel. Catalyst life was assessed both with laboratory grade high FFA feedstocks as well as unrefined yellow grease feedstocks. TiO and MnO were each tested with multiple feedstocks for 4000 minutes of processing and exhibited minimal decreases in catalyst life. Catalyst leaching was evaluated both by simple titration and by metals-specific ICP-MS. While the catalysts are insoluble in water, they were found to produce low levels of soap with high FFA content feedstocks. The levels of soap formed are dramatically lower than with conventional liquid acid/base processes, and are well within the limits of cost-effective removal by ion-exchange resins or filtration media. Even with these robust catalysts, equilibrium values of bound glycerin and free acid were close to the maximum specified values. Optimizing the reactor configuration yielded a robust - it worked for virgin oil and 15% FFA feedstock - and effective process, achieving conversion with glycerin as low as 0.02% (0.24% maximum) and acid value as low as 0.32 (0.5 maximum). The estimated yield of clean product (biodiesel and glycerin) for this final sample of 15% FFA yellow grease feedstock was 99.35%. This number represents the amount of original convertible material (tri, di, monoglycerides and FFA) which was converted to FAME through the process plus the glycerol layer. The other 0.65 % represents unconverted tri, di, and monoglycerides, fatty acid chains bound to metals as soap, and FFA. Glycerin was tested for ash content from two samples obtained from virgin oil and 15% yellow grease. The ash from the virgin oil glycerin was 0.008%, while the ash from the yellow grease oil was 0.83%. Both of these numbers are well below ash levels typical of the industry which are around 10%.
Publications
- No publications reported this period
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