Characters and thermodynamic study on adsorption of coal with different maceral composition on CO

According to the fact that long-term excess-standard CO in low-to-medium metamorpic grade coal seams has not caused coal spontaneous ignition, this paper has carried out the experimental research on adsorption test of eight typical coal samples with different maceral compositions on CO under different pressures. Comprehensive thermodynamic studies on the corrected adsorption volume were conducted by applying physical chemistry, interface chemistry, coal petrology and coal chemical engineering knowledge. Adsorptivity was evaluated from three aspects, including specific surface area, adsorption capacity on per surface area, and interaction between CO molecule and coal surface. The results show that the adsorption of inertinite is better than that of vitrainite. The change rule in free energy of coal surface under different balance conditions shows that the surface free energy of coal samples with higher vitrinite content is greater than that with higher inertinite content. This explais the main reason why the inertinite has a better adsorption. The isosteric heat of coal samples with higher inertinite content is greater than that with higher vitrinite content and the interaction between CO molecular and coal morphology in coal samples with higher inertinite is greater than that with higher vitrinite.