Evaluation of membrane-assisted hybrid processes for the separation of a tetrahydrofuran-methanol-water mixture

The combination of pervaporation (PV) and distillation provide considerable potential for the separation of azeotropic multicomponent mixtures. However, only a proper techno-economic evaluation of these processes compared to a reference process enables a reliable evaluation of benefits. Within this work, the potential of a PVassisted distillation process is evaluated for the mixture of tetrahydrofuran methanol and water compared to a heat-integrated pressure-swing distillation process. Since initial evaluations reveal a significant potential of the PV-assisted processes regarding the required energy demand, experimental investigations of three polymeric and two inorganic membranes were conducted. A detailed characterization of the most promising membranes PERVAPTM 4155-40 and Hybrid Silica HybSi (R) AR was performed, and the latter one provided the highest permeance and selectivity. Based on the derived flux models, an economical optimization was performed. Despite the energy-benefits of the PV-assisted processes, the reference process was still evaluated more favorable under the considered framework, mainly caused by high investment and cooling costs. The current study illustrates the benefits of a tight integration of model-based process design and experimental investigations. Despite possible energy savings and promising performance metrics of the membrane, an assessment of the techno-economic performance of these processes is of major importance to identify applications.

Automated summary

Experimental evaluation of pervaporation-assisted distillation processes showed potential in energy savings compared to traditional pressure-swing distillation, but high investment and cooling costs still made the reference process more favorable.