Influence of Thermal Diffusivity on Isothermal Heating During Auto-gasification

Gasification is a thermo-chemical process of converting solid combustible matter of fuel into gaseous fuel using sub-stoichiometric quantity of air. Gasification of biomass for power generation is found to be more useful and economically viable. Two kinds of biomass widely existing are bio-residues and biomass generated. Bio-residues are waste generated during processing of agricultural produces like rice husk, coir pith, bagasse, saw dust etc. and are powdery and porous in nature. Biomasses generated are either grown in energy plantation or waste generated from the saw mills. Mechanism of gasification of these biomasses differs from one another. In bio-residues, the temperature is uniform throughout the particle and reaction takes place continuously at all points with same rate of reaction. In biomass generated, the thermal properties vary along the thickness resulting in non-uniform temperature. This leads to drying, devolatilization and gasification simultaneously and yielding gases of varied composition. Every biomass is originated to have an adequate amount of oxygen (bio-oxygen) to convert carbon active in it, to carbon monoxide thus signify Auto-gasification and is found to be feasible. Kinetics of auto-gasification of poplar wood dust has been elucidated at a heating rate of 5°C per minute in static air condition. The effect of particle size and shape, initial porosity, moisture, environment, medium, heating rate, ash, external mass transfer resistance, order of reaction, temperature and thermal properties of wood on heating on the auto-gasification of poplar wood dust has been studied and proved.