Upgrading Fast-Hydropyrolysis Products of Cellulose to Higher Molecular Weight Products Using Systems-Level Molecular Mapping

Many of today’s chemicals are derived from fossil resources, which are not only limited, but have a detrimental environmental impact particularly increasing greenhouse gas emission. Producing chemicals in a fossil fuel deprived future requires systematic utilization of renewable carbon sources such as biomass. Biorefinery concept entails the systematic design of processes that convert biomass to chemicals and fuels. Currently, most biorefinery designs do not thoroughly consider the underlying biomass conversion reaction systems and only focus on existing processes, which do not produce all chemicals and fuels that come from traditional refineries.

Toward developing an integrated biorefinery, we develop a holistic and systematic approach to biorefinery design by fully considering the underlying biomass conversion reaction systems. Our approach considers the biomass-to-chemicals landscape, which mainly consists of primary and subsequent processes. Using automated reaction network generator, we exhaustively define the possible search space of the reaction system. We then construct a reaction-separator superstructure and determine the optimal reaction route through optimization. In order to select thermodynamically feasible reaction route, we also consider thermodynamic parameters in our approach.

To illustrate our approach, we present a case study on upgrading fast-hydropyrolysis of cellulose to higher molecular weight molecules. Levoglucosan and glycol aldehyde are the major components in fast-hydropyrolysis of cellulose. Identifying the optimal reaction route to convert these molecules to higher molecular weight compounds are crucial in order to improve their fuel qualities. In this study, we identified several promising reaction routes to convert the vapor to higher molecular weight compounds and showed that key intermediates are required in order to allow carbon coupling between glycol aldehyde and levoglucosan.