Chemical structure and pyrolysis characteristics of demineralized Zhundong Coal

摘要

To investigate the effects of acid treatments on the chemical structure and pyrolysis behavior of coal, we examined the low-rank Zhundong coal pre-treated by four single acids (HCl, HF, H2SO4, HNO3) and a combined acid (HCI-HF-HCI). Our results indicated that the carboxylic and phenolic hydroxyl contents of the coal increased, while the aliphatic and aromatic hydrogen contents decreased after leaching. Nitric acid destroyed long aliphatic chains in coal, which caused the key pyrolysis stage to occur at lower temperature, the number of volatiles increased, and the pyrolysis rate improved.