CBET: A two step chemocatalytic conversion of cellulosic biomass to hydrocarbon biofuels

Prairie View A & M University, Prairie View TX

Investigators

Abstract

The long-term security of our economy requires a portfolio of domestic feedstocks to produce fuels and chemicals. Biomass is a promising choice; however, conversion technologies that are reliable, reproducible and economic are still needed. This project addresses fundamental knowledge supporting a conversion technology uses resources that are targeted solely for fuels production. This project addresses direct conversion of lignocellulosic biomass into a bio-oil that has the potential to be a drop-in replacement for gasoline and other fuels. These fuels would be applicable in current automotive internal combustion engines and for air transportation. The project researches a novel catalyst that serves three functions to break up the biomass structure of cellulose, hemicellulose, and lignin into smaller chemical entities that are converted into a fuel mixture. The catalyst mixture is recyclable and readily recovered from the product mixture. Potential savings are gained in a simpler 2-step process, recycling of catalyst, and higher yield of product from the feedstock. The resulting product would be stable and have high energy content to mix into existing fuel stockpiles. The project's educational activities stress undergraduate research and outreach to high school students for participation in STEM careers. The objective of the project is to research an energy efficient recyclable two step catalytic process for the transformation of biomass to next generation hydrocarbon biofuels. This goal will be achieved by the design of a recyclable catalyst that can produce C5-C20 range partially oxygenated furanic alkene type biocrude oil from lignocellulosic biomass in a single reactor operation under mild conditions. In the first conversion step, cellulose and hemicelluloses in the biomass undergoes an acidic ionic liquid catalyzed depolymerization to glucose and xylose at a relatively low temperature. In the next stage the catalyst will dehydrate the monosaccharides into a furan mixture, 5-hydroxymethylfurfural and furfural. In the final reaction step, the furan aldehydes will undergo acid catalyzed aldol condensation with acetone in the medium. The complex product will consist of C5-C20 range compounds resulting from cross aldol condensation between biomass derived furans and acetone, as well as acetone self-condensation products. The biocrude produced by this catalytic process is stable and composed of well-defined stable furanic alkene and enone products, which are then upgraded to hydrocarbons using established catalytic reduction technology.