Thermolysis and kinetic parameters determination of biomass fuel powders by differential thermal gravimetric analysis (TGA/DTG/DTA)

The kinetics of the thermal decomposition of the agriculture residues were evaluated using a differential thermo-gravimetric analyser under a non-isothermal condition. The direct Arrhenius plot method and the integral method were applied for the determination of kinetic parameters: activation energy, pre-exponential factor, and order of reaction. The thermal behaviour and pyrolysis of two types of biomass i.e. parlmillet cob and eucalyptus by using TGA from ambient to 1000°C. Three different heating rate (10, 15, and 20°C/min) was taken for the thermogravimetric analysis. The carrier gas nitrogen was used in this investigation and the flow rate was 40 ml/min. Thermo-physical properties of agricultural residues in order to facilitate its further processing and utilization for syngas production in the gasifier. Suitability of biomass for gasification and power generation was prejudged by its thermo-physical properties. Agriculture residue had three mass loss step assigned to first one removal of moisture, the second was the main component (cellulose and hemicellulose degradation) decomposition and last dissociation of other organic matters. The cellulose and hemicellulose in biomass were playing an important role in combustion and pyrolysis. The reactivity of lignocellulose present in the biomass was low in combustion. Cellulose content biomass decomposed at a lower temperature due to oxygen diffused in the pores of biomass. The weight loss curve showed that pyrolysis of Eucalypts and Millet cob powders took place mainly in the range of 150–500°C. The activation energy of the millet cob powder and eucalyptus obtained by the direct Arrhenius plot method 70 and 85.5 kJ/mol respectively. On the other side, the integral method shows larger values of activation energy (77–91.2 kJ/mol). The pearl millet cob powder exhibits higher H: C and O: C ratios compared to the eucalyptus, so it has better high heating energy (HHV) value compared to the eucalyptus. The DTG profile for the Pearl Millet Cob shows one peak in the moisture region. This moisture peak has a value of 7.08 %/min and appears at a higher temperature of 279 °C compared to the Eucalyptus whose moisture peak occurred at about 163°C. This shows that the moisture in the Pearl Millet Cob material is entrained in its cell walls and for this particular structure its evaporation requires more energy and this occurs at higher temperatures. The results showed that the apparent activation energy of Pearl Millet changed along with the conversion rate, had the lowest residue content and Ea. This fundamental study provides a basic insight into the Perl Millet Cob pyrolysis, which can benefit our current work in developing advanced thermal processes for high-yield producer gas production from pearl millet cob waste.