(590a) Comparative Techno-Economic and Lifecycle Assessment of Electrochemical Processes for Lignin Valorization

Lignin is an abundant renewable resource that can processed into biofuels, chemicals, and other high-value-added products. Lignin is commonly combusted in biorefineries to produce heat and power. Higher value applications could improve the profitability and sustainable of second generation biorefineries. This study evaluates the commercial potential of electrodeless electrochemical (EC) conversion as a strategy for lignin valorization to produce commodity and specialty chemicals.

In this study, a techno-economic (TEA) and lifecycle (LCA) evaluation of a lignin valorization process was carried out in order to determine its feasibility and to demonstrate lignin’s potential as a value-added product. We developed a chemical process model in BioSTEAM based on the National Renewable Energy Laboratory (NREL) biorefinery design. A portion of the lignin stream was diverted to the EC unit for chemical production.

Experimental data for this analysis is based on phthalimide‐N‐oxyl (PINO) type catalysts. The performance of the PINO-type catalysts mediated electrochemical oxidation was evaluated to determine the yield and selectivity. Through integrating chronoamperometry, all of the charges flowing through the electrochemical cell were determined (i-t curve). Accordingly, Faraday's effectiveness was calculated.

We determined that a 2,000 metric tonne per day (tpd) biorefinery could produce between 4.4 and 37 tpd of chemicals by processing 50% of process lignin. The primary chemical by mass is syringaldehyde (16.6 tpd), and vanillin is the most valuable by revenue ($206,000/day). The bulk chemical minimum selling price ranges between $1.15 and $7.10 per kg. We estimated the maximum EC capital investment to range $5 and $50 million for chemical prices of $1 to $10/kg. These results indicate that a EC unit could generate additional revenues to second generation biorefineries. Future studies will evaluate the impacts of product composition on the commercial potential of this technology.