Nonseparative Catalytic Reaction Applications

As briefly mentioned earlier in this chapter, the porous matrix of an inorganic membrane can be applied as a well-engineered catalytic reaction zone where the catalyst is immobilize on the pore surface or the membrane is inherently catalytic to the reaction involved. 

The opposing-reactant geometry has been studied recently by several investigators for a number of catalytic reactions including destruction of NOx [Zaspalis et al., 1991d], conversion of hydrogen sulfide to sulfur [Sloot et al, 1990 and 1992] and oxidation of carbon monoxide [Veldsink et al, 1992]. 

Apparently at a temperature above 300 C, the oxidation kinetics of NOx and ammonia gas is so fast that slip of the reactants, when fed from the opposite sides of an alumina or alumina-titania membrane, can be avoided. Vanadium oxide, used as the catalyst for the reaction, is impregnated onto the membrane pore surface. The conversion of NOx reach 70% with the selectivity for nitrogen up to 75% in the temperature range of 300 to 350 C [Zaspalis etal., I991d]. 

Sloot et al. [1990 and 1992] successfully investigated the reaction between hydrogen sulfide and sulfur dioxide at a temperature ranging from 200 to 270X using the 

Similarly the fast oxidation reaction of carbon monoxide proves to be amenable to the concept of opposing-reactant geometry [Veldsink et al., 1992]. In this case, alpha-alumina membrane pores are deposited with platinum as the catalyst for the reaction to proceed at about 250°C. 

---