Fabrication of membrane reactors

11 Structure of the disc/flat-sheet membrane reactor (a) catalyst packed on membrane and (b) catalyst coated on membrane with electrodes and external circuit. 

Sometimes, an external circuit is estabhshed by fixing a gold lead on each side of the membrane with gold or silver paint, which are fired at an elevated temperature. The setup of Fig. 7.11b can also be used to measure the polarization of the membrane surface and to evaluate the activity of oxygen at the surface of the membrane and its evolution during catalytic reactions (Lbfberg et ah, 2004). 

Thermowell Quartz jacket F ex ring Membrane tube 

12 Schematic diagram showing (a) the tubular membrane reactors and (b) the dead-end tubular membrane reactor for the partial oxidation of ethane. 

The use of a dead-end ceramic membrane tube can make the assembly of the membrane reactor much simpler. As shown in Fig. 7.12(b), a dead-end ceramic membrane tube is sealed onto the muUite tube in which a smaller dense alumina tube is coaxially placed. The whole system is sited in a quartz tube, which serves as the shell side in the reactor operation. The short step in the mullite tube serves as a holder for both the seal material and the membrane. For the Bii jYojSnio 2O3 (BYS) membrane mounted to the mullite tube, the sealant consisting of 45 wt% BYS, 25 wt% SrCeo.95Tbo.05O3,10 wt% Pyrex glass, 10 wt% NaA102 and 10 wt% B2O3 can be used (Akin and Lin, 2002). 

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