Collaborative Proposal: Effect of theral treatment on biomass structure and hydrocarbons production using catalytic pyrolysis processm
The conversion of biomass to pyrolysis oil (i.e., bio-oil) and subsequent upgradation to gasoline and diesel range compounds have a significant potential in reducing the United States? dependence on imported petroleum products. Using fast pyrolysis technology, a high yield of bio-oil can be achieved from various biomass feedstocks. However, bio-oil is unstable and acidic, contains char particles, and has about half the heating value of petroleum liquid fuels. Acidity, high viscosity, high oxygen content, difficulties in removing char particles, and immiscibility with petroleum liquids have restricted the use of bio-oil. A catalytic pyrolysis process has been found to be effective in alleviating some of the negative properties of the bio-oil. The catalytic process-- that uses some shape selective zeolites-- involves the cleavage of C-C bonds associated with dehydration, decarboxylation, and decarbonylation, and produces aromatic compounds.
Torrefaction process has been used to pretreat biomass feedstocks in order to reduce oxygen content with the assumption that as a result less oxygenated compounds, that are more stable and have higher heating value, can be produced using pyrolysis process. The central hypothesis of this study is that the cleavage of weak ether and glycosidic bonds as a result of thermal treatment can increase aromatics yield in biomass pyrolysis process. This project examines the effects of thermal treatment on biomass properties and its structure. In addition, the relationship between biomass structure and the hydrocarbon yields in shape selective catalysts will be elucidated. Past studies on torrefied biomass pyrolysis have investigated the effect of physicochemical properties on bio-oil yield without developing detailed understanding of biomass structure and its impact on liquid product. In addition, although the importance of Bronsted acid sites on catalytic pyrolysis has been recognized for a long time, the relationship among biomass properties, number of acid sites, spectrum of hydrocarbon products after pyrolysis, and coke formation is not understood. The role of acid (Bronsted) sites in H+ZSM-5 catalyst will be elucidated in catalytic pyrolysis of torrefied biomass to maximize hydrocarbons production and minimize coke formation. This research will provide a fundamental understanding of the chemistry that occurs on the zeolite catalysts when thermally treated --structurally damaged-- biomass is pyrolyzed.
Biomass-derived liquid fuels have a potential to provide a cost-effective and sustainable supply of energy, while meeting greenhouse gas reduction targets. The successful completion of this project will have an impact on the profitability of farming, forest products, and pulp industries in the United States. The project will train a new generation of graduates with its multidisciplinary focus on bio-energy research, while providing a solid fundamental background in their core areas, which will help transfer technology to U.S. industry, thereby enhancing its competitiveness in the field of energy technologies. As a part of the human development process, the PI will involve K-12th grade teachers and students in this project using the existing infrastructures at Auburn University.
