Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

KN-6individual reaction stages within certain phases of the technological cycle, which opens upwide prospects for the varying of the reactant concentrations on the catalyst surface. In manycases, the correct arrangement of this process in combination with the temperature factorallows one to overcome the equilibrium limitations and reach higher yields of target productsas compared with analogous stationary processes. It is interesting that in many cases, theparameters of non-stationary modes substantially depend on the factors that play a minor roleor have an indirect effect on the stationary technologies. These factors include the energy ofthe reactant bond with the catalyst surface, the heat capacity of the catalyst, its specificsurface, etc.Prospective for application of unsteady catalytic and sorption-catalytic processes areanalyzed for different case applications: VOC incineration, NOx reduction, purification ofautomotive exhausts, the Claus process, H 2 S decomposition, SO 2 oxidation, hydrogen andsyngas production by steam conversion of methane and CO, the Deacon process, selectiveoxidation of hydrocarbons and others.The following advantages of the sorption-catalytic technologies over the stationarymethods can be mentioned:• principally new options for heat management, possibility to perform highly-exothermalreactions in packed adiabatic beds without catalyst overheating;• a decrease in the energy consumption in processing of low-concentration gases;• an increase in the efficiency of cleaning of exhaust gases;• the shift of equilibrium in thermodynamically limited reactions;• the enhanced selectivity of partial «anaerobic» oxidation processes using thechemisorbed oxygen as a «soft» oxidant.In many cases, these advantages may include the reduction in the capital costs in and also,paradox as this may look at the first glance, the simplification of technological schemes andthe enhancement of their operation stability.In general, unsteady state and sorption-catalytic ideology discovers new degrees offreedom for process development and may become the basement for new generation ofhighly-efficient catalytic technologies in the nearest future.26