CURRENT HURDLES TO THE SUCCESS OF HIGH-TEMPERATURE MEMBRANE REACTORS

High-temperature catalytic processes performed using inorganic membranes have been in recent years a fast growing area of research, which seems to have not yet reached its peak. Chemical engineers, catalysts and materials scientists have addressed this topic from different viewpoints in a common effort. Despite the amount of work already carried out, the direct application of inorganic membrane reactors in the process industry is still limited because of a large number of technical and economic drawbacks. The opportunities of this novel type of reactor compared with conventional reaction and separation systems have been emphasised in several former reviews. In the present contribution attention is focused on the major hurdles along the way of exploitation of these possibilities: high costs, low permeability, synthesis of defect-free permselective layers, instability of membranes and catalysts, sealing of membranes into modules, etc. An assessment of what has been already accomplished in the attempt to overcome these limitations is given, stressing the gaps still to be filled and pointing the way towards future efforts to reach this goal.