High-temperature membrane reactors: potential and problems

The most recent literature in the field of membrane reactors is reviewed, f our years after an analogous effort of ours (Saracco et al., 1994), describ ing shortly the potentials of these reactors, which now seem to be well est ablished, and focusing mostly on problems towards practical exploitation. S ince 1994, progress has been achieved in several areas (sol-gel deposition of defect free sol-gel derived membranes, reduction in thickness of Pd memb ranes, synthesis of zeolite membranes) whereas stagnation was noticed in so me others (high-temperature sealing of membranes into modules, scaling-up o f membrane reactor, etc.). As a result, despite the still increasing resear ch efforts, industrial application does not seem to be round the corner, ye t. However, several non-permselective membrane reactor opportunities with c urrently available membranes might pave the way for more sophisticated appl ications. (C) 1999 Elsevier Science Ltd. All rights reserved.