(365c) Techno-Economic and Sensitivity Analysis of Aromatic and Alkene Production from Lignin Via Fast Pyrolysis and Catalytic Upgrading Coupled with Ethanol Production.

Lignin is one of the most abundant existing biopolymers, often underutilized due to its complex structure and chemical composition. In biorefineries, lignin is commonly burned to supply heat and power to the system due to lower costs. While this is currently sufficient, it may be more cost challenging in the future as more advanced biofuel production processes are being developed. Therefore, it is necessary to investigate methods to increase the value of lignin to improve the feasibility of biofuel production. This study looks at the robustness of fast pyrolysis combined with catalytic hydrodeoxygenation process using molybdenum trioxide to convert lignin components into three primary streams: aromatics, alkenes, and alkanes which reduces the need and cost for separation. This process upgrades lignin into aromatics, alkenes, and alkanes to be sold as by-products to increase the value of lignin while improving the cost of ethanol at a biorefinery. Several lignin types (organosolv corn stover, organosolv poplar, Dupont, and Renmatix lignins) were investigated in this study, and the results were compared to a base case for which lignin is simply used as a heat and power source.

The techno-economic analysis (TEA) combines the biochemical process of ethanol production with the thermochemical process of upgrading lignin to chemicals. Based on the combination of various economic parameters, historical market prices, plant life of 30 years, and a 2000 MTPD input biorefinery, capital costs for a 61 million gallon per year (MGPY) cellulosic ethanol plant is estimated at $401 million (MM) while equipment costs were estimated to be $214 MM. The pyrolysis and catalytic upgrading process account for 22% of the total capital costs. TEA shows that the upgrading of lignin into aromatics, alkenes, and alkanes and selling them as by-products can reduce the selling price of cellulosic ethanol by $1.67-2.02/gallon as compared to when lignin is used as power ($2.20/gallon). Sensitivity analysis shows that the minimum selling price of ethanol is highly sensitive to the price of aromatics, operating hours, and capital costs as compared to other operating parameters such as fuel and char output.