Combustion characteristics of coal gangue and biomass under an O2/CO2 atmosphere

Abstract

Oxygen concentration and biomass content are key factors of the combustion of a mixed sample of biomass and coal gangue. Herein, we studied the effect of oxygen concentration and biomass content and their corresponding combustion and kinetic characteristics. Experiments were conducted in a thermogravimetric analyzer under an O2/CO2 atmosphere. Results showed that the fixed carbon combustion temperature, ignition temperature, and exothermic peak temperature decreased with oxygen concentration increased. By contrast, the burning rate of volatilization increased with oxygen concentration increased. The total and maximum loss rates of the sample, the burnout temperature, the exothermic peak temperature, and the comprehensive combustion index S gradually increased. As oxygen concentration increased, the activation energy at the initial stage of combustion gradually decreased, whereas the activation energy at the end of the reaction gradually increased when the oxygen concentration increased. Activation energy could be rapidly reduced after a small amount of biomass was added, whereas the biomass content had no significant influence on the activation energy of the samples at the end of combustion.