Modeling and Experimental Studies on CO2 Gasification of Coarse Coal Char Particle

Gasification study of a single Indian sub-bituminous coal char particle is carried out in the temperature range of 880-910 degrees C in a pure CO2 atmosphere. Two temperatures, 900 and 800 degrees C, are used for char preparation, and the char obtained at higher temperature is found to be more reactive. A fully transient nonisothermal model is developed incorporating the reaction kinetics along with transport limitations. Spatial and temporal variation of thermo-physical properties like thermal conductivity, diffusivity, and density of the gas mixture and variable specific pore surface area and accessible porosity are included in the model. The model computation shows that the combined kinetics and heat transfer model is more effective to predict the experimental findings of the present authors and that reported in the literature. The simulation study is carried out to assess the effect of reaction temperature, particle size, and char reactivity on the particle temperature, conversion, gasification rate, and CO and CO2 mass fractions within the porous volume of the particle.