Investigation of the Changes in Hydrogen Bonds during Low-Temperature Pyrolysis of Lignite by Diffuse Reflectance FT-IR Combined with Forms of Water

Xiangchun Liu, Tsuyoshi Hirajima, Moriyasu Nonaka, Keiko Sasaki

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Abstract

The changes in the hydrogen bonds (HBs) of Loy Yang lignite during low-temperature pyrolysis were investigated. The water content of all of the samples was determined by weighing the samples before and after heating in an oven. The changes in the number of the different types of HBs were determined using diffuse reflectance Fourier transform infrared spectroscopy considering the forms of water in lignite. The number of absorption bands, their peak positions, and the area of each peak in each spectrum were determined by curve-fitting analysis with the mixed Gaussian and Lorentzian function. The quantified integrated area of aromatic hydrogen atoms was used to accurately investigate the changes in the HBs. The results showed that the freezable and nonfreezable water contents of the total water weight in raw lignite were 84.8% and 15.2%, respectively. At low temperatures (T ≤ 100 °C), the main removed water was freezable water. The number of OH-lignite interactions decreased compared with raw lignite, which can be attributed to the breaking of bound-water-cluster-lignite HBs. The removal of free water induced a decrease in the number of OH-OH interactions, and then the transition of free water to bound water increased the number of OH-OH interactions. At medium temperatures (100 < T ≤ 200 °C), bound and nonfreezable water were mainly removed. The number of OH-lignite and OH-OH interactions changed because of the competition between the transition of bound water to nonfreezable water and desorption of bound and nonfreezable water. At higher temperatures (200 < T ≤ 250 °C), nonfreezable water was the main form of water removed, and carboxyl groups started to drastically pyrolyze. OH-lignite interactions changed as a result of the removal of nonfreezable water and the pyrolysis of carboxyl groups.

Original languageEnglish
Pages (from-to)8971-8978
Number of pages8
JournalIndustrial and Engineering Chemistry Research
Volume54
Issue number36
DOIs
Publication statusPublished - Sep 16 2015

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Coal
Lignite
Hydrogen bonds
Pyrolysis
Water
Temperature
Water content
Curve fitting
Ovens
Weighing
Fourier transform infrared spectroscopy
hydroxide ion

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

Cite this

@article{1773f3bee73d48cebed071f1f405ce4a,
title = "Investigation of the Changes in Hydrogen Bonds during Low-Temperature Pyrolysis of Lignite by Diffuse Reflectance FT-IR Combined with Forms of Water",
abstract = "The changes in the hydrogen bonds (HBs) of Loy Yang lignite during low-temperature pyrolysis were investigated. The water content of all of the samples was determined by weighing the samples before and after heating in an oven. The changes in the number of the different types of HBs were determined using diffuse reflectance Fourier transform infrared spectroscopy considering the forms of water in lignite. The number of absorption bands, their peak positions, and the area of each peak in each spectrum were determined by curve-fitting analysis with the mixed Gaussian and Lorentzian function. The quantified integrated area of aromatic hydrogen atoms was used to accurately investigate the changes in the HBs. The results showed that the freezable and nonfreezable water contents of the total water weight in raw lignite were 84.8{\%} and 15.2{\%}, respectively. At low temperatures (T ≤ 100 °C), the main removed water was freezable water. The number of OH-lignite interactions decreased compared with raw lignite, which can be attributed to the breaking of bound-water-cluster-lignite HBs. The removal of free water induced a decrease in the number of OH-OH interactions, and then the transition of free water to bound water increased the number of OH-OH interactions. At medium temperatures (100 < T ≤ 200 °C), bound and nonfreezable water were mainly removed. The number of OH-lignite and OH-OH interactions changed because of the competition between the transition of bound water to nonfreezable water and desorption of bound and nonfreezable water. At higher temperatures (200 < T ≤ 250 °C), nonfreezable water was the main form of water removed, and carboxyl groups started to drastically pyrolyze. OH-lignite interactions changed as a result of the removal of nonfreezable water and the pyrolysis of carboxyl groups.",
author = "Xiangchun Liu and Tsuyoshi Hirajima and Moriyasu Nonaka and Keiko Sasaki",
year = "2015",
month = "9",
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doi = "10.1021/acs.iecr.5b02474",
language = "English",
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journal = "Industrial & Engineering Chemistry Research",
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T1 - Investigation of the Changes in Hydrogen Bonds during Low-Temperature Pyrolysis of Lignite by Diffuse Reflectance FT-IR Combined with Forms of Water

AU - Liu, Xiangchun

AU - Hirajima, Tsuyoshi

AU - Nonaka, Moriyasu

AU - Sasaki, Keiko

PY - 2015/9/16

Y1 - 2015/9/16

N2 - The changes in the hydrogen bonds (HBs) of Loy Yang lignite during low-temperature pyrolysis were investigated. The water content of all of the samples was determined by weighing the samples before and after heating in an oven. The changes in the number of the different types of HBs were determined using diffuse reflectance Fourier transform infrared spectroscopy considering the forms of water in lignite. The number of absorption bands, their peak positions, and the area of each peak in each spectrum were determined by curve-fitting analysis with the mixed Gaussian and Lorentzian function. The quantified integrated area of aromatic hydrogen atoms was used to accurately investigate the changes in the HBs. The results showed that the freezable and nonfreezable water contents of the total water weight in raw lignite were 84.8% and 15.2%, respectively. At low temperatures (T ≤ 100 °C), the main removed water was freezable water. The number of OH-lignite interactions decreased compared with raw lignite, which can be attributed to the breaking of bound-water-cluster-lignite HBs. The removal of free water induced a decrease in the number of OH-OH interactions, and then the transition of free water to bound water increased the number of OH-OH interactions. At medium temperatures (100 < T ≤ 200 °C), bound and nonfreezable water were mainly removed. The number of OH-lignite and OH-OH interactions changed because of the competition between the transition of bound water to nonfreezable water and desorption of bound and nonfreezable water. At higher temperatures (200 < T ≤ 250 °C), nonfreezable water was the main form of water removed, and carboxyl groups started to drastically pyrolyze. OH-lignite interactions changed as a result of the removal of nonfreezable water and the pyrolysis of carboxyl groups.

AB - The changes in the hydrogen bonds (HBs) of Loy Yang lignite during low-temperature pyrolysis were investigated. The water content of all of the samples was determined by weighing the samples before and after heating in an oven. The changes in the number of the different types of HBs were determined using diffuse reflectance Fourier transform infrared spectroscopy considering the forms of water in lignite. The number of absorption bands, their peak positions, and the area of each peak in each spectrum were determined by curve-fitting analysis with the mixed Gaussian and Lorentzian function. The quantified integrated area of aromatic hydrogen atoms was used to accurately investigate the changes in the HBs. The results showed that the freezable and nonfreezable water contents of the total water weight in raw lignite were 84.8% and 15.2%, respectively. At low temperatures (T ≤ 100 °C), the main removed water was freezable water. The number of OH-lignite interactions decreased compared with raw lignite, which can be attributed to the breaking of bound-water-cluster-lignite HBs. The removal of free water induced a decrease in the number of OH-OH interactions, and then the transition of free water to bound water increased the number of OH-OH interactions. At medium temperatures (100 < T ≤ 200 °C), bound and nonfreezable water were mainly removed. The number of OH-lignite and OH-OH interactions changed because of the competition between the transition of bound water to nonfreezable water and desorption of bound and nonfreezable water. At higher temperatures (200 < T ≤ 250 °C), nonfreezable water was the main form of water removed, and carboxyl groups started to drastically pyrolyze. OH-lignite interactions changed as a result of the removal of nonfreezable water and the pyrolysis of carboxyl groups.

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JO - Industrial & Engineering Chemistry Research

JF - Industrial & Engineering Chemistry Research

SN - 0888-5885

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