Zeolite membrane reactors

Zeolite membranes for their well defined pore size, high thermal and chemical stability can be used as membrane reactors. However, the development of zeolite membrane reactors requires the preparation of defect-free membranes. Up to now, different methods for their preparation were developed, such as in-situ and secondary growth method. The secondary growth method has a variety of advantages such as easier operation, higher controllability in crystal orientation, microstructure and film thickness, better reproducibility with respect to the in-situ method. Despite the enormous efforts made to improve the quality of the membranes, their industrial application on large scale is confined to T and NaA topologies to use in pervaporation and vapour permeation processes. Besides, the commercial zeolitic membranes are not yet employed in gas separations for the presence of intercrystalline defects. For this problem and also for the addition of other disadvantages as the reproducibility problems in the preparation step, the cost of the membrane module and their sealing at high temperatures, there are relatively few papers on the use of zeolite membrane reactors in different processes of industrial interest. Therefore, further improvements are necessary to facilitate the introduction of the zeolite membrane reactors in the industry.