Integrated system design for dewatering of solvents with microporous silica membranes

The technical and economical feasibility of inorganic membranes was evaluated for the dewatering of organic solvents by pervaporation. A mapping of the process industry was carried out in order to examine the most attractive applications. The performance of an amorphous silica membrane was screened in more than 30 systems. The membrane combines excellent water permeances of 10 to 20 kg/m2hbar with very good selectivity of up to several 1000. For inorganic high performance membranes the design of efficient modules is important. Different concepts for tubular geometry have been compared and optimized. On the level of process development several configurations for an integration of pervaporation and vapor permeation with distillation have been evaluated. Savings in energy consumption of up to 85% are possible. Investment and running costs can be reduced by 40% in comparison to conventional processes.

The technical and economical feasibility of pervaporative dewatering of organic solvents with amorphous silica membranes was proved with success. Experimental performance data was collected for more than 30 industrial relevant applications. Hybrid process design and optimization was carried out for the dehydration of isopropylalcohol. Even in this standard case a total cost reduction by 40% and energy savings up to 85% could be shown. For a fast industrial implementation of this promising new separation technology further research and development in the direction of long-term operation security is needed. This includes material stability improvement and on-site demonstration on pilot and technical scale with real process streams.