Process Modeling and Techno-Economic Assessment of the Conversion of Biorefinery Lignin to Dicarboxylic Acids

The development of commercially viable, integrated biorefineries remains a difficult challenge. A key barrier is the lack of a strong value proposition for the lignin waste stream. Most approaches towards lignin valorization have focused on the depolymerization of lignin to phenolic compounds, but a class of chemicals –dicarboxylic acids– have largely been overlooked as a potential lignin product. Dicarboxylic acids are important and highly valuable industrial chemicals and intermediates used across the biopolymer, pharmaceutical, and food additives industries. Though the oxidative aromatic cleavage of lignin is a well-known reaction during the delignification of wood pulp, it is only recently that the selective production of dicarboxylic acids from biorefinery lignin has been demonstrated as a mild, environmentally friendly process. Development of this new pathway and its potential impact on biorefineries remains to be explored.

In this study, we will present several process models for the oxidative conversion of biorefinery lignin to dicarboxylic acid products, developed in Aspen Plus. We will evaluate and compare their technical and economic feasibilities, and present sensitivity analysis on key process parameters. Process and cost bottlenecks will be identified and discussed as potential areas for future research and improvement.