A systematic molecular design framework for an environmentally benign solvent recovery process

Computer Aided Molecular Design (CAMD) techniques have been extensively applied to design solvents for different applications. Most of the CAMD problems only aim at generating solvents that meet the predefined functionality. Nevertheless, it is important to consider the effect of solvent on the safety, health and environmental impacts during the recovery process. This paper presents a single stage CAMD framework that simultaneously quantifies the environmental impact of the solvent recovery process. The environmental impact of the process can be estimated through IChemE Sustainability Metrics. Besides, molecular properties that have an impact on the quantitative evaluation of the environmental impact of solvent recovery process are included in this framework. Weighted sum method coupled with Fuzzy Analytic Hierarchy Process (FAHP) weighting approach is employed to solve the multi-objective molecular design framework. A case study on solvent design for residual oil extraction from palm pressed fiber is presented to illustrate the proposed framework. In this work, only energy balance around multistage evaporator is incorporated into CAMD formulation as energy required to recover the solvent contributes to the largest portion of the whole process. The results show that the designed solvents simultaneously possess target functionalities and reduce the environmental impact of solvent recovery process.