Table 1 Non iso-thermal/dynamic kinetic study and iso-thermal study in thermal analysis [16,17,18]

To obtain the thermo gravimetric curve, the heating rate is variable in non iso-thermal process/study.

In iso-thermal study/process, the heating rate is always kept same whereas the temperature of isotherms is varied and the estimation of decomposition time is carried out for the selected range.

When heating rate of the non iso-thermal process is increased the thermal curves as well as the fractional conversion move into the high temperature zones. The initial gasification temperature and the total gasification temperature when increasing the time taken for the gasification process reduces.

In iso-thermal process when temperature is increased, the gasification processes gets accelerated. The time which is required to reach the peak conversion is reduced as the gasification rate and gasification temperature is increased.

The Ozawa dynamic method is applied for studying the non iso-thermal process in thermal analysis. In this Ozawa dynamic model, different heating rates (β) °C min⁻¹ and the dynamic air atmosphere (50 mL min⁻¹) is maintained and the sample was analyzed.

In the iso-thermal study, the sample is heated with the heating rate (β) of 20 °C min⁻¹ from room temperature till it reduces to T_isotherm- 10 °C; further, the sample is heated with heating rate (β) of 2 °C min⁻¹ from T_isotherm- 10 °C to T_isotherm, and finally the temperature is kept constant until the sample mass is reduced by at least 10% of the initial sample mass.

Activation energy is obtained by plotting log β vs 1/T further kinetic parameters frequency factor and reaction order can be obtained by implying Arrhenius equation k(T) = A.e^−Ea/RT

Activation energy is obtained by plotting ln T Vs 1/T at constant conversion level and calculations are carried out using Arrhenius equation k(T) = A.e^−Ea/RT and reaction order and frequency factors are calculated.