Catalytic Combustion of Carbon

R. P. Viswanath and P. Wilson

Department of Chemistry, Indian Institute of Technology Madras

Chennai 600 036, Tamilnadu, India

Abstract

Present day energy needs of mankind are strongly dependent on the combustion of fossil fuels and other carbonaceous materials. The combustion reaction is accompanied by simultaneous production of gaseous pollutants like CO, NOx and SO2. In the catalytic combustion, the advantages are two fold: i. The combustion efficiency will be higher and this results in the higher energy realization and ii. The operating temperatures being much lower the emission level of the pollutants also will be greatly reduced. In this study, thermogravimetric analysis (TGA) has been used in following the non-isothermal kinetics of the combustion using two different models.

In the present study an attempt has been made to evaluate from the thermogravimetry, the kinetic parameters for carbon combustion in oxygen and their dependence on the catalyst present in the system. Four different supported systems have been used for the oxidation. Similarly, four different pure carbon materials, differing in their surface areas and crystallinity, have been investigated. For evaluating the catalytic activity, two rate equations have been applied for the isothermal oxidation kinetics of the carbon samples. The catalytic activity on the oxidation of carbon has been observed in the form of lower ignition temperature and a decrease in the energy of activation. The possible role of oxygen spill-over is discussed.