Coproduction of butene oligomers and adipic acid from lignocellulosic biomass: Process design and evaluation

A new process for the coproduction of butene oligomers (BO) as biofuel and adipic acid (ADA) as a high-value chemical from lignocellulosic biomass is developed. In the proposed process, the split mass ratio of gamma-valerolactone (GVL) are controlled for efficient production of BO and ADA according to the market requirements of each product. Three distinct strategies are investigated, wherein the GVL split mass ratio is varied to produce BO and ADA in ratios of 2:1, 1:1, or 1:2, demonstrating how process economics are affected by modification of fuel and chemical production. The minimum selling prices of BO are calculated as 4.74, 3.14, and 2.90 dollars per gallon of gasoline equivalent in each case, indicating that the process in which BO and ADA are produced in a ratio of 1:2 is the most economical. Key cost drivers for the process are identified from sensitivity and uncertainty analyses. Additionally, life cycle assessment (LCA) is performed to investigate the environmental impacts of the proposed process. When the production ratio of BO and ADA is 2:1, the environmental impact is minimal, showing 0.151 kg CO₂ eq and −0.075 kg oil eq, respectively, for climate change and fossil depletion.