Membrane reactors for the study of homogeneous and heterogeneous reactions using ceramic and ceramic/polymeric membranes

A study is presented of the use of catalytic ceramic and polymeric/ceramic membranes in membrane reactors for the investigation of thermodynamically limited chemical reactions. Ceramic and polymeric/ceramic membranes are currently utilized for the separation of gases or liquids. The application of such membranes to catalytic reactors is based on their ability to shift the equilibrium conversion by selectively removing a particular product species.; In this study a high temperature catalytic membrane reactor, consisting of an alumina ceramic membrane tube packed and impregnated with a commercial chromia catalyst and supported in a shell-and-tube arrangement, was used to study the heterogeneous isobutane dehydrogenation reaction. In the experiments the effect of residence time, temperature, and the shellside sweep gas ratio were investigated. Conversion and yield were obtained which were higher than the corresponding equilibrium values calculated under the same experimental conditions. The permeation of various gases through this catalytic ceramic membrane was shown to follow a Knudsen diffusion mechanism.; A polymeric/ceramic membrane tube was also utilized in a membrane reactor in the study of the homogeneous esterification reaction of ethanol and acetic acid. The preparation method of the polymeric/ceramic composite membrane has been studied. The permeability of the various liquids are investigated. For a range of experimental conditions of temperature, space time, and inlet composition, reactor conversions were observed which are again higher than the corresponding calculated equilibrium values. A simple theoretical tubular pervaporation membrane reactor model has been developed which without adjustable parameters gives a reasonable fit to the experimental results.