Low-cost ceramic membranes and supports for gas separation

The objectives of this program are to: 1. Develop a passive, highly selective, molecular sieve membrane capable of purifying coal process conversion gases at temperatures over 600[degrees]C. 2. Fabricate and determine the performance characteristics of such a membrane based on a practical (i.e., low cost, high surface area) support module. In the first year of the program a number of membrane compositions and processing techniques were evaluated with the objective of producing gas separation membranes with subnanometer pore diameter. This work involved use of 25 mm diameter alumina ultrafiltration disks as membrane supports and investigated membrane coatings of refractory oxides, including alumina, zirconia, ceria, and silica. During this first year, a preferred membrane composition and processing conditions were identified that allowed fabrication of disk-supported membranes with sub-manometer size pores. Continuing work in this area during the second year of the program involved optimization of the fabrication of these gas separation membranes and determination of their gas permeability properties at temperatures up to 200[degrees]C. Disk-supported membranes were fabricated that exhibited molecular sieving behavior and He/N[sub 2]selectivities in excess of 50 at 200[degrees]C. Two other elements of this project were initiated during the first two years of this program and are themore » focus of current experimental work. One of these elements involves application of gas separation membranes to commercially obtained ceramic tubular ultrafiltration (UF) membranes. The second element involves continued investigations related to application of gas separation membranes to low-cost, high-surface-area ceramic ultrafiltration modules based on honeycomb monolith supports (manufactured by CeraMem Corporation). This paper relates current findings in these areas of investigation.« less