1992 Volume 78 Issue 7 Pages 990-997
In the process of the gas phase reaction on porous catalysts, all the surface area is not used for the reaction because of the gaseous diffusion resistance inside the particle of catalysts. For the rate expression of such reaction, the effectiveness factor of porous catalyst is often used. However, in some cases it is difficult to obtain the value of effectiveness factor.
In this study, the non-linear expression of reaction rate for water gas shift reaction was converted into linear form by introducing Taylor's expansion and the equation for calculating the effectiveness factor of porous reduced iron pellets was derived.
The effect of the following factors on the effectiveness factor was discussed. They were the temperature at which the porous reduced iron pellets were prepared, the pressure and the temperature under which the water gas shift reaction took place, the pore structure and impurity of the pellet. The observed and calculated effectiveness factors showed similar trend. Namely, the effectiveness factor increased with increasing the temperature for the preperation of porous reduced pellets, with increasing the reaction pressure and with decreasing the temperature for water gas shift reaction.
In the measurement of the effectiveness factor with industrial pellets, about 10 times larger value than the theoretical one was obtained. This discrepancy was reasonably explained by the effect of impurity in the pellet.
