(396b) Small Pore Zeolite Membranes for CO2 Capture
AIChE Annual Meeting
Tuesday, November 5, 2013 - 6:00pm to 8:00pm
From the environmental and energy perspective, purification and recovery of carbon dioxide from flue gas and natural gas are of great interest. CO2 must be separated from CH4 because it reduces the energy content of the natural gas, and it is acidic and corrosive in the presence of water. Although polymeric membranes such as cellulose acetate, polyimide and polyaramide can separate CO2 from CH4 and H2 mixtures, the high CO2 pressures plasticize them and decrease their separation ability considerably. Zeolite membranes have significant advantages over polymeric membranes. They do not deform under high CO2 pressures, have high thermal, mechanical, and chemical stability, and good erosion resistance. Of particular interest are small pore zeolites having three dimensional structures with pore sizes in the 3.5-3.6 Å range which represents an ideal pore window to molecular sieve CO2 (3.3 Å) from CH4 (3.8 Å) and N2 (3.6 Å). Herein, we present our initial efforts to develop small pore zeolite membranes (including SAPO-56, DNL-6 and zeolite Rho) and evaluate its separation performance for CO2/CH4 gas mixtures. The membranes were supported on porous alumina tubes, and were grown via secondary seeded method. In particular, SAPO-56 displayed moderate CO2 permeances and selectivities for equimolar CO2/CH4 mixtures.