Study of combustion and pyrolysis behavior of waste biomass and kinetic study by Thermo-gravimetric analysis (7714)
The main objective of the present study is to investigate the combustion and pyrolysis behavior of waste biomass and the affect of cellulose, hemicellulose, lignin content to the decomposition and to select the most attractive biomass from the waste source for energy recovery and also determine the suitable degradation kinetic model. Biomass can be classified according to their availability and nature. To accomplish this, five types of waste biomass viz. jatropha husk and Masau ferrea husk from biodiesel industry and soya husk, rice husk and coconut husk from food processing industry were selected on the basis of availability in local area and high energy producing capacity. The characterization of selected waste biomass was carried out by using proximate and ultimate analysis, weight loss kinetics, fiber analysis, calorific value and bulk density etc. The weight loss kinetics of these waste biomass was investigated by using Thermo-gravimetric analysis (TGA) in air and nitrogen atmosphere at a gas flow rate 5,10,15,20 ml/min and constant heating rate 10oC/min in a temperature range of 30 – 900oC. Kinetic parameters viz. activation energy (Ea), frequency factor (A), rate constant (K) were also calculated using coats and redfern method, friedman method and differential method for first order kinetics. It has been concluded that in inert atmosphere the activation energy of all biomass varies from 60 to 90 kJ/mol while in air atmosphere activation energy varies from 58 to 106 kJ/mol. Thus, it was found that the soya husk has the lowest activation energy (Ea) of 60 kJ/mol in air and nitrogen atmosphere and also has high cellulose content which may enhance the ignition characteristic. The Coats and Redfern method was more suitable for calculating activation energy because it gives lower value of activation energy than any other method in both atmosphere. Most of the biomass degraded in the temperature range of 200 to 550oC in air atmosphere while 200 – 600oC in nitrogen atmosphere. It was also observed that the degradation of biomass was more rapid in air than nitrogen atmosphere. Among all the biomass, Masau ferrea husk has the highest calorific value of 21.11 MJ/kg. While coconut husk has high bulk density, thus soya husk, mesua ferrea husk and coconut husk are suitable waste biomass as compare to jatropha shell and rice husk for energy recovery.