Thermo-kinetic Study of Genetically Different Carbon-Source Materials

Area of Science:

• * Chemical Engineering
• * Materials Science
• * Energy Science

Background:

• * Understanding the devolatilization kinetics of various carbonaceous materials is crucial for optimizing pyrolysis processes.
• * Different feedstocks like coal, biomass, lignite, and petcoke possess unique physiochemical properties influencing their thermal decomposition behavior.
• * Previous studies have often focused on single feedstock types, necessitating a comparative analysis across diverse origins.

Purpose of the Study:

• * To determine the devolatilization kinetic parameters for coal, biomass, lignite, and petcoke using nonisothermal thermogravimetric analysis (TGA).
• * To investigate the influence of ash composition, morphology, and structure on the thermo-kinetic behavior of these diverse materials.
• * To apply the Coats-Redfern kinetic model to quantify activation energies for the devolatilization process.

Main Methods:

• * Nonisothermal thermogravimetric analysis (TGA) conducted at heating rates of 10, 15, and 20 °C/min from 25-1000 °C under an inert atmosphere.
• * Proximate and ultimate analyses for physical and chemical characterization.
• * X-ray fluorescence (XRF) for ash composition analysis.
• * Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) for morphological and structural analysis.

Main Results:

• * Petcoke samples displayed the highest activation energies (Ea) ranging from 57.17 to 67.58 kJ/mol across the tested heating rates.
• * Lignite samples exhibited the lowest activation energies (Ea), between 12.84 and 16.03 kJ/mol.
• * A correlation was observed between thermo-kinetic behavior and the catalytic effects of ash composition, material morphology, and structure.

Conclusions:

• * The devolatilization kinetics vary significantly among coal, biomass, lignite, and petcoke, with petcoke being the most thermally stable and lignite the least.
• * Ash composition and the inherent physical structure of the carbon source materials play a significant role in their pyrolysis behavior.
• * This comprehensive physiochemical analysis provides valuable insights for optimizing slow pyrolysis processes for different carbonaceous feedstocks.