Kinetic of the pyrolysis process of peach and apricot pits by TGA and DTGA Analysis

Abstract

The kinetic constant rate of the slow pyrolysis process has been estimated, at non-isothermal states, through TGA analysis (Thermogravimetry) for two typologies of biomass: peach and apricot pits. Thermal degradation was implemented using two heating rates (HR), 10 °C/min and 20 °C/min, with the aim of estimating the influence of such parameter on the process kinetics. Results, obtained through the Derivative Thermogravimetric Analysis (DTGA), illustrate that volatilization of both peaches and apricots starts at 200 °C and degradation mainly takes place in the temperature range 200-400 °C. At the end of the thermal degradation process (T = 600 °C), the amount of weight loss was 63÷73% and 58÷60% respectively for peach and apricot pits. It was found that the heating rate considerably influences the weight loss and kinetic constants. Higher heating rates provoke the shift of thermograms towards more elevated temperatures. The energy of activation of the pyrolysis process was calculated by the Friedman model and, for the HR of 10 C/min, it was discovered that this one is fairly independent by the range of conversion. Instead, for the HR of 20 °C/min, the energy of activation decreases, in average by 35%, while the conversion range rises.