Recycling and recovery of solvents is an important downstream issue that should be considered. Solvent recovery can have a positive effect on the environmental impact and hence the metrics of a given process. Studies have been carried out to determine whether solvent recovery is viable depending upon factors such as the energy required to achieve this. [1] ETH Zurich has also developed an LCA based tool that allows the environmental impact of waste-solvent treatment to be quantified.
The incineration of spent solvent as opposed to their recovery has been shown to considerably increase the life cycle impacts.[2] However, this depends on the complexity of the production of the solvent itself and its boiling point; for solvents such as diethyl ether, incineration is a more preferable option than distillation in terms of Total Cumulative Energy Demand (CED).[3]
Where solvent recovery is deemed to be uneconomical, other options include down-cycling the solvent for example for heat recovery or use in other industrial applications.[4]
Other approaches could include solvent ‘leasing’ whereby used solvent is collected by supplier and cleaned up for reuse.
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