Studies on auto gasification of coir pith

Abstract

Gasification is a thermo-chemical process of converting solid combustible matter in the solid fuel into gaseous fuel using sub-stoichiometric quantity of air. Gasification of biomass for power generation is more useful as it is economically viable at all capacities. two kinds of biomass namely bio-residues and biomass generated. Bio-residues are waste generated during processing of agricultural produces. They are rice husk, coir pith, bagasse, saw dust etc. and are powdery and porous in nature. Biomasses generated are either grown in energy plantation or saw mill waste. Mechanism of biomass differs from one another. In the porous 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 taking place simultaneously and yielding gases of varied composition.Most of the biomass gasifiers are working at high temperatures between 9000C and 11000C so as to get the gasification process completed. The necessary heat required for raising the temperature is supplied by burning a portion of biomass. The flue gases generated along with the presence of N2 in the air supplied for gasification dilutes the producer gas resulting in a very low specific calorific value. If it were possible to gasify completely the biomass with least or no air at all, at lower temperatures then the specific calorific value of producer gas generated could be the highest.Every biomass is found to have enough oxygen (bio-oxygen) to convert carbon in it to carbon monoxide. The ash is observed to catalyze the reaction. Auto gasification of biomass using bio-oxygen and catalytic ash is found to be feasible. carbon, hydrogen and oxygen components are assumed to be chemisorbed on the ash matrix and heating decomposes them. The production of agricultural crop residues in India is over 1300 million tones per year