R. Struis, S. Stucki, Michael Wiedorn
May 1, 1996
Citations
3
Influential Citations
103
Citations
Quality indicators
Journal
Journal of Membrane Science
Abstract
Abstract Methanol synthesis from CO 2 and H 2 is a promising chemical energy storage reaction for hydrogen. The methanol yield of the synthesis is limited by the thermodynamic equilibrium at the temperatures required by state-of-the-art catalysts. Substantial conversion improvements would be achieved by selective product separation from the catalyst bed of a synthesis reactor. A perfluorinated cation exchange material (Nafion ® , DuPont) is evaluated for use as a vapour permeation membrane at temperatures up to 200°C. The permselectivities for methanol and water with respect to hydrogen depend on the counter ion in the polymer, and drop as a function of temperature. With respect to long term stability and performance, lithium is best suited as a counter ion, with permselectivities of 32 for water, and 5.6 for methanol, respectively. Permeability and permselectivity are found to increase with increasing partial pressures of both methanol and water vapours. The capability of the Li-Nafion membrane to separate products from a commercially available catalyst bed operating on CO 2 and H 2 at 200°C is demonstrated using a simple tubular membrane reactor module.