Transport and separation properties of a silicalite-1 membrane - I. Operating conditions

Results are reported for the one-component permeation of a number of gases through a silicalite-l membrane. The effect of several operating conditions , like the temperature, the feed pressure, the sweep gas flow rate, and the orientation of the membrane; on the Hull are discussed. The optimal experi mental conditions are identified for both steady state and transient permea tion. Results for the flux as function of the pressure, 10-900 kPa, and as function of the temperature, 200-700 K, are modelled taking two diffusion m echanisms into account. Permeation results are reported for two different s ilicalite-l membranes. A small difference in the permeance is observed, ind icating a high reproducibility of the zeolite membrane synthesis. The contr ibution of the equilibrium isotherm to the flux and the permeance is demons trated. A comparison is made between results obtain with helium and argon a s the sweep gas. Finally, results are reported for the permeation of pure g ases through a silicalite-l membrane modified by silanation. (C) 1998 Elsev ier Science Ltd. All rights reserved.