Development of Continuous Process Concepts for Upgrading Lignin in Biorefineries

(Supported by the NSF Partnerships for Innovation (PFI) Program, $550,000, in collaboration with ADM)

This project is developing a bench-scale process for sequentially converting lignin to platform chemicals and materials. Producing value-added products from lignin will create a major source of bio-renewable aromatic chemicals, and will also significantly improve the overall economics of cellulosic ethanol in the biorefinery, which remains uncompetitive compared to conventional gasoline.

Several reported technologies specifically process lignosulfates, alkene-rich grass lignin and alkaline lignins. The proposed suite of technologies accommodates a wider array of alkaline, organosolv and milled lignin feedstocks from different industrial and agricultural sources. The novelty stems from the fact that the modules will sequentially attack the C=C bonds (by ozonolysis) followed by C-O bonds (with solid Lewis acid catalysts) to isolate various value-added fractions with facile membrane-aided separation of the low molecular weight products.  Optimized spray ozonolysis reactors (for C=C cleavage) and durable catalysts for C-O cleavage in lignin depolymerization will be demonstrated. This work will develop and optimize the reaction and separation steps at the bench scale using real biorefinery feed stocks, yielding data to support a thorough techno-economic assessment.