The cost of feedstock is a dominant factor in the final cost of renewable biofuel production. Therefore, maximizing the value of each biomass component is an ideal opportunity to improve the economics and commercial potential of lignocellulosic biomass conversion to liquid fuels. Biomass is composed of three main constitutive bio-polymers: cellulose, hemicellulose, and lignin. Lignin is a highly cross-linked, oxygenated aromatic polymer that is very difficult to decompose due to its robust structure. This has limited the industrial applications of lignin with the exception of energy production from direct combustion. The goal of this SBIR project is to develop and demonstrate an effective and cost competitive lignin depolymerization method to realize the potential for high value biomass products from residual lignin produced during biorefinery processing. Low yield, severe treatment conditions and complex product mixtures are among the main drawbacks of existing lignin conversion methods. Our solution utilizes a novel pathway with significant advantages: 1) lignin oxidation with low energy input requirements and mild conditions versus the traditional reduction reaction under high temperature, high pressure and hydrogen consumption; and 2) sequential depolymerization and oxidation to dicarboxylic acids using catalytic processing in an integrated continuous flow reactor system that eliminates the inefficiencies of batch processing. Identifying catalysts to selectively convert lignin to valuable products will offer a breakthrough solution to biorefinery lignin valorization and significantly alter the economics of lignocellulosic biomass-to-biofuel conversion. Phase I work will include catalyst and process development, reactor design, and laboratory trials to a) investigate the kinetics and mechanisms of catalytic oxidation reactions with residual lignin, b) optimize lignin depolymerization and maximize the ring cleavage reactions, c) develop a continuous flow reactor system for lignin processing, and d) conduct a preliminary techno-economic analysis of the process. The reactions will be carried out under mild conditions of temperature and pressure, thereby lowering energy requirements and reactant costs. Process economics models will be used to assess the commercial feasibility of our technical approach to convert biomass lignin to high value commodity products. Commercial Applications and Other
Benefits: The proposed technology will facilitate the replacement of fossil fuels with renewable fuels for transportation by adding value to biomass by-products. In addition to improving our energy security and mitigating climate change, the potential benefits to society also include stimulating our economy by keeping dollars in our domestic economy and generating job opportunities, particularly in rural areas. Key Words: biomass conversion, lignin, renewable transportation fuels, green gasoline, cellulosic biomass, catalytic processing, lignin oxidation, dicarboxylic acids Summary for Members of Congress: Converting domestic biomass into affordable, renewable fuels and products supports our national strategy to diversify energy resources and reduce dependence on imported oil. This project will develop catalytic processing technology that converts non-food biomass to valuable chemicals to help improve the economics of biofuel production.
