Lignin to Adipic Acid

Lignin, a heterogeneous mixture made up of aromatic polymers, is a major co-product produced from second generation cellulosic ethanol plants. Currently lignin is being burned as a low energy fuel; however, since the number of second generation cellulosic ethanol plants in the U.S. is expected to increase over the next several years, a more profitable alternative for lignin is desired. The National Renewable Energy Lab (NREL) has been working towards developing a process that converts lignin to adipic acid, a significant dicarboxylic acid that is used to produce nylon-6,6. This process utilizes bacteria for a biological conversion of lignin, which is much more environmentally friendly than the current petrochemical methods of producing chemically derived adipic acid. The goal of this project was to analyze the lab data released by NREL and determine the feasibility of bringing this process to industry. This was accomplished by designing an industrial scale process based off of the current availability of lignin. A cost and profitability analysis was performed for this design and safety and environmental concerns were also researched and addressed. All of these aspects were taken into consideration to determine if this process would be worth bringing to industry and if it would pose a threat to the current petrochemical process for the production of adipic acid.