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

Abstract

A thermogravimetric study of the oxygen gasification of a commercial active carbon using Go, Ni and Cu as catalysts has been carried out. This follows a previous study of the influence of the particle size, gas volumetric flow rate, initial sample weight temperature and oxygen partial pressure an non-catalytic gasification. The results show that for T<500 °C; P02<1 atm; Dp<0.4 mm, Qv>50 cm3 min-1 and Mo<75 mg the gasification 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 activation energy and the reaction order with respect to oxygen and the catalyst to 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-catalytic processes, which were also determined.