Session: I&EC General Posters:

Traditional methods of waste solvent disposal, such as incineration have proved to be less favorable to the environment, creating an immediate need for efficient solvent recovery pathways. Although solvent recovery processes improve the cost and sustainability, there has not been an integrated method to simultaneously quantify the environmental impacts and economics of a process. This work incorporates a sustainability matrix and economic evaluations into the framework and uses a multi-objective optimization approach to evaluate solvent recovery options. The sustainability index used is the Sustainable Process Index (SPI). SPI quantifies the arable area needed to provide goods and services. Every process requires a certain area within the ecosystem to take place. The SPI is made up of seven footprints, quantified as area, namely: area needed for installations and infrastructure, renewable resources, non-renewable resources, fossil carbon usage, areas to embed air, water, and soil emissions after the process.

Economic feasibility is evaluated via a detailed stagewise superstructure optimization method encompassing solvent recovery, waste treatment technologies, and stream connections. The technology models consist of material and energy balances, equipment design and costs, labor, consumables, and overhead costs. The optimal path is selected using mixed-integer nonlinear programming methods, where active and inactive technologies are denoted by 1 and 0 respectively and all other model equations are usually nonlinear.

Through this research, it has been shown that the economics are at the forefront of process selection. When targeting the recovery from waste streams, as in case of solvent-containing streams, it is imperative to consider the environmental impacts as well. This integrated multi-objective approach provides a promising solution to developing a solvent recovery process that integrates both economic and environmental aspects.

Kirti Yenkie

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