Evolvement behavior of microstructure and H2O adsorption of lignite pyrolysis

doi:10.1016/j.cjche.2016.04.012

Abstract

Abstract: The effect of pyrolysis on the microstructure and moisture adsorption of lignite was investigated with low field nuclear magnetic resonance spectroscopy. Changes in oxygen-containing groups were analyzed by Fourier transform infrared spectroscopy (FTIR), and H₂O adsorption mechanism on the surface of lignite pyrolysis was inferred. Two major changes in the pore structure of lignite char were observed as temperature increased in 105-200℃ and 500-700℃. Pyrolysis temperature is a significant factor in removing carboxyl and phenolic hydroxyl from lignite. Variation of ether bond content can be divided into three stages; the content initially increased, then decreased, and finally increased. The equilibrium adsorption ratio, content of oxygen-containing groups, and variation of pore volume below 700° were closely correlated with each other. The amount of adsorbed water on char pyrolyzed at 700℃ increased. Moreover, the adsorption capacity of the lignite decreased, and the adsorption state changed.

Key words: Lignite, Pore structure, Moisture adsorption, Oxygen-containing Groups

摘要： The effect of pyrolysis on the microstructure and moisture adsorption of lignite was investigated with low field nuclear magnetic resonance spectroscopy. Changes in oxygen-containing groups were analyzed by Fourier transform infrared spectroscopy (FTIR), and H₂O adsorption mechanism on the surface of lignite pyrolysis was inferred. Two major changes in the pore structure of lignite char were observed as temperature increased in 105-200℃ and 500-700℃. Pyrolysis temperature is a significant factor in removing carboxyl and phenolic hydroxyl from lignite. Variation of ether bond content can be divided into three stages; the content initially increased, then decreased, and finally increased. The equilibrium adsorption ratio, content of oxygen-containing groups, and variation of pore volume below 700° were closely correlated with each other. The amount of adsorbed water on char pyrolyzed at 700℃ increased. Moreover, the adsorption capacity of the lignite decreased, and the adsorption state changed.

关键词: Lignite, Pore structure, Moisture adsorption, Oxygen-containing Groups

Yingyue Teng, Shijun Lian, Quansheng Liu, Yuzhe Liu, Yinmin Song, Runxia He, Keduan Zhi. Evolvement behavior of microstructure and H₂O adsorption of lignite pyrolysis[J]. Chin.J.Chem.Eng., 2016, 24(6): 803-810.

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Evolvement behavior of microstructure and H₂O adsorption of lignite pyrolysis

Evolvement behavior of microstructure and H₂O adsorption of lignite pyrolysis

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