화학공학소재연구정보센터
Chemical Engineering Science, Vol.63, No.20, 5071-5075, 2008
Non-parametric determination of reactivity distribution for nitrided Mo/Al2O3 catalysts during dibenzothiophene HDS
The non-parametric determination of the activity distribution of the catalytic sites on a nitrided 12.5% Mo/Al2O3 catalyst during the hydrodesulfurization (HDS) of dibenzothiophene was studied. The equation for dibenzothiophene HDS was described as a Fredholm integral equation of the first kind, r(t) = f h(t, k) . f (k) dk, where r(t) is the rate of the HDS reaction, h(t, k) is a kernel of exp(-kt) and f(k) is the distribution of reactivity of the adsorbed species on the surface sites, i.e., the distribution of activity of the catalytic sites. The 12.5% Mo/Al2O3 nitrided at 973 K contained one active site with an average k, value of 0.55 at a population of 60.6%, while the others contained fewer active sites below the k(1) value of 0.13 at 39.4%. These two distinct patterns supported the fact that two active sites with different rate constants imposed the C-S hydrogenolysis and hydrogenation of dibenzothiophene on the nitrided 12.5% Mo/Al2O3 catalysts. The active sites with an average k(1) value of 0.55 were 36-49 times larger than those that exhibited smaller k(2) values. The activity and distribution of the catalytic sites of the nitrided 12.5% Mo/Al2O3 catalysts during the dibenzothiophene HDS are discussed. (C) 2007 Published by Elsevier Ltd.