Experimental verification of ceramic membrane potentials for supporting three-phase catalytic reactions

Progress in performance and stability of a contactor-type Catalytic Membrane Reactor for wet air oxidation

“…The gas overpressure was monitored and carefully controlled using a pressure-difference gauge connected to a PID regulator, acting on the gas feed through a mass-flow 2). In mode 2, according to Laplace's law, a gas overpressure was used to displace the gasliquid interface by flushing the liquid through the pores of the different layers, in order to bring it as close as possible to the active top-layer [9]. The membrane reactor operated either in continuous mode, the liquid being passed continuously through the reactor, or in recycling mode, the liquid phase being recycled into the reactor for a total volume of 300 mL.…”

“…Furthermore, when compared with the other mode (mode 1, gas inside, liquid outside) the position of the gas-liquid interface inside the macroporous layers may give additional benefits from the shorter diffusion path of reactants and products in the liquid phase [8,9] and by the limited amount of membrane material in contact with the acidic medium. Finally, as industrial effluents may content particulates, this feeding mode will limit membrane fouling.…”

“…The gas-liquid interface is then located within the membrane by means of the transmembrane differential pressure that is compensated by the capillary pressure of the liquid within the membrane pores. Detailed investigations of mass-transfer in three phase processes on membrane catalytic contactors, as well as of the effects of the gas-liquid interface location within the membrane wall on the overall process performance have been thoroughly reported [8][9][10].…”

Positioning of the reaction zone for gas–liquid reactions in catalytic membrane reactor by coupling results of mass transport and chemical reaction study

“…This time was taken into account in our analysis as the time zero. Samples were taken periodically from the reactor through syringe sampler (7). The protocol used during mass transport studies was identical, only acid injection procedure was skipped.…”

“…Reif and Dittmeyer [6] suggested that for the case when internal diffusion in CMR is a rate determining step, the reactor productivity could be increased by pumping reaction mixture with the dissolved reactant through the membrane; they reported that such operation can increase reactor productivity up to five times. Vospernik et al [7] showed that it is possible to control position of gas-liquid interface inside the membrane wall by applying different www.elsevier.com/locate/cattod Catalysis Today 105 (2005) 589-597 trans-membrane pressure. By proper adjustment of transmembrane pressure, it was possible to increase mass transport through the membrane for more than 20 times compared to liquid full operation.…”