New Way To Increase Catalyst Activity
NEW WAY TO INCREASE CATALYST ACTIVITY
M. A. Glikin, D. A. Kutakova, I. M. Glikina, A. I. Volga
State Research and Design Institute
of Chemical Technology “Khimtekhnology”
1, Vilesov Str., Severodonetsk, Lugansk region, 93400, Ukraine
fax: (06452) 25367, E-mail prin@ixt.lg.ua
The catalysts on carriers are widely used in industrial catalysis. The field of use of catalytic systems is limited by application of carriers. The industrial practice shows that precipitation of coke, polymers, salts on catalyst surface and in its pores results in its deactivation. The attrition and loss of catalyst take place both in fluidized bed and moved bed processes even when modern carriers are used. Narrow choice of the carriers and their modifications, complicated production, substantial prime cost, durability and heat resistance limits reduce the application field of traditional catalysts.
Alternative search has led to development of new gas phases catalytic processes. It’s based on the catalysis on the fine-grained active catalytic material sprayed in the reactor.
The investigation has shown that the new technology has the following specific features in the kinetic mode:
– Absence of intradiffusional stage in chemical reaction;
– The reaction rate is determined by either reagents transfer or by the frequency of contacts between the reagents and the catalytic particle surface;
– The reaction magnitude is close to one;
– The observed activation energy is up to 30 kJ/mol.
The application of aerosol of fine-grained metal particles, their oxides and salts solves the problem of the catalyst durability and heat-resistance. It allows to remove the reaction products, such as coke, salts, etc. from the catalyst surface by mechanical particles elimination in the fluidized inert bed, as well as to regenerate the catalyst activity. Thus the catalyst self-regeneration and activation take place directly in the reaction zone.
Stable aerosol conditions are ensured at catalyst particle dimensions less than 100 nm. Particle vorticity and developed external catalytic surface ensure
equal access of reagents to the active catalytic surface. It’s known that higher particle dispersity changes properties of the surface, including the ones defining the catalytic efficiency, such as adsorption, electric conductivity, surface energy, surface tension, electron’s work function, electromagnetic effect. According to our opinion the increase of the reaction rate in catalyst aerosol by 4 to 5 orders of magnitude can be explained by the transfer to application of ultradispersed particles (nano-size) without carrier. It was proved during pilot plant and industrial plant tests of such processes as: vinylation, hydration and dehydration, cracking, the deep and partial oxidations of organic and inorganic compounds.
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