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.