Synthesis of Porous Ceramic Materials for Catalytically Active Membranes by Technological Combustion and Sintering
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SYNTHESIS OF POROUS CERAMIC MATERIALS FOR CATALYTICALLY ACTIVE MEMBRANES BY TECHNOLOGICAL COMBUSTION AND SINTERING V. I. Uvarov,1, 3 R. D. Kapustin,1 A. S. Fedotov,2 and A. O. Kirillov1 Translated from Steklo i Keramika, No. 6, pp. 24 – 29, June, 2020.
A porous, catalytically active membrane based on coarse-fraction silicon carbide was synthesized. Ultrafine additives with an eutectic composition of magnesium oxide and silicon carbide, which during sintering at temperatures from 1100 to 1450°C form a liquid phase in the form of clinoenstatite MgSiO3 that wets the coarse-size SiC particles and forms a strong porous framework of the membrane, were introduced into the initial SiC powder to synthesize the membranes. The pore size of the ceramic material was studied as a function of the pressing pressure, which made it possible to obtain a highly porous ceramic membrane with pore size optimized for dehydrogenation of ethylbenzene into styrene. Modification of the pore surfaces to 10% Re – W by means of active components using the alkoxy method is performed in order to give the synthesized membrane the catalytic properties required for realizing the dehydrogenation process. Key words: Self-propagating high temperature synthesis (SHS), ceramic membrane, porosity, pressure, pressing, dehydrogenation, ethylbenzene, styrene.
the fact that the process is accompanied by numerous ancillary reactions with formation of gaseous products of the transformation of ethylbenzene, such as toluene, benzene, ethane, methane, and carbon oxides, which subsequently interact with one another and form a large number of diverse toxic substances [4]. The solution of these problems will be greatly facilitated by the proposed scientific research work focusing on the development of a novel catalytic membrane process for dehydrogenation of ethylbenzene. The use of membrane reactors based on porous ceramic catalytic converters is an effective way to increase the efficiency of hydrogenation and dehydrogenation processes [5]. This method makes it possible to intensify hydrogenation and dehydrogenation reactions and therefore increase the selectivity of the process with respect to the desired products. On the whole this occurs as a result of the reduction of the overall energetics of the chemical transformation (compared with the conventional reactors with a stationary layer of a granular catalyst) as well as improved heat-and-mass transfer in the highly porous medium of the catalytic converter. The forced diffusion of substrate molecules in the spatially bounded volume of the pores and the high ratio of the area of the catalytic surface to the volume of the internal pores increase a factor that is important factor in catalysis — the fre-
The advancement of the modern chemical industry is exemplified by significant growth in research on ways to increase the efficiency of the conventional production of styrene, as one of the most important products of petrochemistry, as well as by the search for new approaches and engineering solutions
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