Experimental study and thermal analysis of the combustion characteristics of powder-activated cokes

The thermodynamic and kinetic parameters of two powder-activated cokes were investigated. Two powder-activated cokes were prepared from lignite and bituminous coal through the rapid preparation process by one–step activation. Variations in the specific heat capacity, thermal diffusivity, and thermal conductivity with the change in temperature were determined. The effects of heating rate and oxygen concentration on ignition temperatures of the two samples were studied. Ignition temperatures were determined using an improved TG/DTG tangent method and predicted by polynomial models. Ignition temperatures of bituminous coal (sample 2) were higher than those of lignite (sample 1). The kinetic parameters were investigated by the Coats–Redfern method. The effects of heating rate and oxygen concentration on the activation energy and the pre-exponential factor were determined. A kinetic compensation effect existed between the two kinetic parameters. The values of these parameters could be calculated directly by polynomial models and kinetic compensation effect equations.