Collaborative Research: ECO-CBET: Coupled homogeneous and heterogeneous processes for an environmentally sustainable lignin-first biorefinery

A future, environmentally sustainable chemical industry will likely utilize woody biomass as a renewable carbon source. In many biomass conversion processes, chemical reactions in the fluid phase interact with reactions on the surfaces of catalytic materials during forcing conditions of high pressure and elevated temperature. In a recently proposed wood biorefinery, the lignin component of wood is preferentially dissolved and depolymerized to monomers in the fluid phase. Subsequently, the generated monomers need to be stabilized on a catalytic material to avoid formation of undesirable compounds that cannot be further processed. To improve the environmental sustainability and profitability of such a wood biorefinery, this project will accelerate both the lignin depolymerization and the product stabilization by tuning the solvent fluid properties and designing catalysts that are optimized for the reaction environment. Given the complexity of the lignin reductive catalytic fractionation reaction system, it is hardly possible to directly design the catalyst and fluid properties for woody biomass. Because lignin structure varies for different biomass sources, this project will study the coupled homogeneous and heterogeneous processes under realistic reaction conditions for lignin model compounds instead of actual solid biomass. By working with model reactants that contain the critical bond linkages and whose conversion products are representative of the conversion products of woody biomass, the system complexity is dramatically reduced without fundamentally changing the depolymerization and reductive product stabilization chemistry, enabling the concurrent design of fluid properties and catalyst. Overall, this project constitutes a case study of how to use modern data science tools for tightly integrating fundamental computational and experimental research with life cycle assessment, techno-economic analysis, and regular validation of design principles for the conversion of poplar to expedite the development of an environmentally and economically sustainable biorefinery. The education plan includes postgraduate, graduate, undergraduate, and K-12 students. They will be trained in broad research areas while emphasizing the ability to work collaboratively in addressing difficult environmental problems. To engage all team members in unfamiliar fields, students will give tutorial presentations that are aimed at a diverse audience and that can later be adapted into short interactive web-based lectures and web modules on topics such as life cycle assessment and machine learning. Project participants will broaden the participation of underrepresented groups, women, and those with non-traditional backgrounds in science and engineering by engaging in outreach and training programs.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.