Porosity effects on catalytic char oxidation. Part I: A catalyst deposition model

Six char samples generated from two coals were impregnated by solutions with different concentrations of Na2CO3 and /or K2CO3. The catalyst solution penetration was studied, the catalyst uptake was measured, and the effects of impregnation on the char pore structure were determined experimentally. The results indicate that the impregnated catalysts reside only on particle exteriors without significant penetration. The overall rate of reaction is therfore the combination of catalytic reaction on particle exteriors and noncatalytic reaction on the pore surfaces inside the particle. A kinetic model is presented that takes these findings into account.