Study on the Synergistic Caking Mechanism of Vitrinite and Inertinite: Reconstructing Maceral Activity Based on...

Area of Science:

• Coal science
• Materials science
• Chemical engineering

Background:

• Understanding the behavior of coal macerals is crucial for optimizing coal blending and coke production.
• Vitrinite and inertinite are key maceral groups with distinct structural and thermal properties.

Purpose of the Study:

• To analyze the structural differences, pyrolysis behaviors, and synergistic effects of vitrinite-rich and inertinite-rich coal concentrates.
• To investigate the role of inertinite in coke formation and gasification.
• To propose a new evaluation index for coal caking macerals.

Main Methods:

• Separation of high-purity vitrinite-rich and inertinite-rich concentrates (>90%).
• Analysis using coal petrology, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric pyrolysis, and thermogravimetric gasification.
• Evaluation of caking properties and correlation with maceral composition.

Main Results:

• Vitrinite is rich in aliphatic structures and oxygen-containing groups, leading to lower pyrolysis temperatures and higher caking activity.
• Inertinite with reflectance below 1.7% actively participates in plastic mass formation and provides skeletal support for coke.
• Vitrinite coke shows higher gasification reactivity, while some inertinite exhibits high-temperature reactivity.
• A new evaluation index using a 1.7% reflectance threshold for coal caking macerals significantly improved correlation with the caking index.

Conclusions:

• Inertinite is not entirely inert and plays a vital role in coke structure and properties.
• Incorporating low-reflectance inertinite enhances coal's caking potential.
• The study provides a theoretical basis for optimizing coal blending strategies to improve coke quality.