Catalyzed gasification of active carbon by oxygen: influence of catalyst type, temperature, oxygen partial pressure and particle size

A thermogravimetric study of the oxygen gasification of a commercial active carbon using Co, Ni and Cu as catalysts has been carried out. This follows a previous study of the influence of the particle size, gas volumetric flo w rate, initial sample weight temperature and oxygen partial pressure an no n-catalytic gasification. The results show that for T< 500 degrees C; P-o2 < 1 atm; D-p < 0.4 mm, Q(v) > 50 cm(3) min(-1) and M-o< 75 mg the gasificat ion of the active carbon with oxygen is controlled by the chemical reaction . The presence of a catalyst increases in all cases the reaction rate, both temperature and catalyst concentration showing a very positive influence. The activity of the different catalysts follows the order: Co > Cu > Ni. A kinetic study applied to both types of gasification has allowed the activat ion energy and the reaction order with respect to oxygen and the catalyst t o be determined. In all cases both the activation energy and the Arrhenius pre-exponential factor are lower in the catalytic gasification. This brings about the existence of an isokinetic point for the catalytic and the non-c atalytic processes, which were also determined. (C) 2000 Society of Chemica l Industry.