Investigating Kinetic and Thermodynamic Parameters in the Pyrolysis of Sheep Manure Using Thermogravimetric Analysis

The kinetics of the pyrolysis process of sheep manure were investigated using Thermogravimetric Analysis in this work. It was heated at 30 degrees C to 900 degrees C with a heating rate of 10 degrees C/min. There are two stages of mass degradation, namely dehydration and devolatilization. The temperature dehydration stage is 30 degrees C-140 degrees C while the devolatilization stage is 210 degrees C- 900 degrees C. However, at temperatures >500 degrees C, mass degradation decreases until it reaches 900 degrees C. This indicates that most of the volatile matter has disappeared at this temperature. The devolatilization stage includes the decomposition of hemicellulose and cellulose (210 degrees C- 900 degrees C) and lignin (>590 degrees C). The calculated activation energy from Friedman's non-conversional method is 21.32 kJ/mol and Coats-Redfern is 26,20 kJ/mol, while the frequency factor value is 9.94.10(18) 1/s for Friedman and 3.42.10(18) 1/s for Coats-Redfern Method which indicates that the pyrolysis process of sheep manure is a complicated phenomenon. The estimated activation energy value is then used to calculate thermodynamic properties e.g., Gibbs free energy, enthalpy, and entropy.