Thermal Degradation and Kinetic Modelling of Wheat Straw Pyrolysis

The energy demand is growing with a very high rate, which is creating challenges such as climate change, the escalation of the cost of fossil fuels, and an energy crisis. Renewable energy that can be generated is of different types, such as wind, solar, hydro, and biomass. CO2-neutral energy is particularly offered by biomass, that is not only boosts energy security but also enhances environmental and economic sustainability. The current experimental work was carried out to test the pyrolysis degradation behavior and kinetics of Wheat Straw (WS). The thermal decomposition characteristic was observed through the use of a Thermogravimetric Analyzer (TGA) through heating the sample at heating rates of 10, 20, 30, 40, and 50 ºC/min from the ambient temperature up to 850 ºC. The Friedman method was used to compute the kinetic parameters and the master plot analysis. The active pyrolysis region (150-600 ºC) was recorded with the greatest weight loss at all the heating rates during thermogravimetric analysis. It was found that the peak temperature proportionately rose with the increasing rate of heating, which rose between 10 and 50 ºC/min. The solid residue was increased from 28.31% to 29.75% with the increasing heating rate from 10 to 50 ºC/min. The kinetic analysis showed that the beginning of the Activation Energy (Ea) was slightly raised until reaching a value around 0.7. Further, a sharp increase in Ea was observed. Ea calculated values were 113.54 to 310.13 kJ /mol. There was more than 0.99 Coefficient of Determination (R2). The WS pyrolysis tended to obey an order-based model. The Pre-Exponential Factor (A) values were found to be between 7.09×108 and 6.45×1022 s-1. The Ea and the natural logarithm of A were found to have a linear relationship with a high regression coefficient. This research offers an avenue of using agricultural waste in different products of high value through pyrolysis, such as biochar, to improve the soil and to sequester carbon. This encourages the exploitation of agricultural wastes in a sustainable way.