Economic and environmental optimization of the biobutanol purification process

Current technologies for the production of biobutanol by fermentation have improved the production processes. These new technology improvements are economically viable with respect to the petrochemical pathway. For this, the aim of this paper is to compare four different process designs for the purification of biobutanol by solving a multi-objective optimization process involving two objective functions: the total annual cost and return of investment as economic functions and the associated eco-indicator 99 as an environmental function. The process associated to the routes A, B, and C consists of a steam stripping distillation and distillation columns, while the process D includes distillation columns with a liquid–liquid extraction column. Process modeling was performed in the Aspen Plus software, and the multi-objective optimization was conducted using differential evolution with tabu list as a stochastic optimization method. Results indicate that the process route D is the most profitable design and the process route C has the lowest environmental impact measured through the eco-indicator 99 method. Additionally, the use of a solar collector against steam has been compared in order to produce the required heat duty needed in every single distillation column to have a broader view about the environmental and economic impact of these devices.