Thermogravimetric analysis of camel dung, date stone, and their blend for pyrolytic, kinetic, and thermodynamic studies

Abstract

Camel dung (CM) and date stone (DS) are biomass resources that are abundant across the Gulf region and have the potential to produce sustainable renewable fuels and specialty products. Copyrolysis of CM with DS is an intriguing research approach to boosting both the production and quality of pyrolysis products, particularly biochar. The current study investigated the bio-energy potential of CM, DS, and CD-DS blend by assessing their physicochemical attributes, pyrolysis characteristics, and kinetic behaviour using thermodynamic analysis. To investigate the pyrolysis behaviour, the materials were thermally decomposed using a thermogravimetric analyser under non-isothermal conditions at different heating rates in a nitrogen environment. The findings of the physicochemical analysis established the bio-energy potential of the feedstocks for long-term energy generation. Thermal degradation profiles of the samples revealed multistage degradation due to the various components in their structure. While a positive synergistic effect between DS and CD was observed in the thermal profile of the blend. The average apparent activation energy of CD from the Friedman method, Flynn–Wall–Ozawa (FWO) model, Kissinger–Akahira–Sunose (KAS) method, and Starink model was 324, 167, 157, and 158 kJ/mol, respectively. Friedman, FWO, KAS, and Starink methods yielded average activation energies of 621, 315, 276, and 279 kJ/mol for DS, respectively. The mean activation energy of the blend estimated using the Friedman, FWO, KAS, and Starink methods was 210, 216, 206, and 207 kJ/mol, respectively. The thermodynamic outcomes reveal that slow pyrolysis of the specified feedstocks is a nonspontaneous process requiring external energy for their degradation. The findings of this study may aid in a better understanding of reaction processes and the expansion of pyrolysis applications of DS, CD, and their mix.