SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2018, Vol. 26 ›› Issue (7): 1545-1554.DOI: 10.1016/j.cjche.2018.05.012

• Energy, Resources and Environmental Technology • 上一篇    下一篇

Experimental study on the effects of drying methods on the stabilities of lignite

Yixin Zhang1, Jixiang Dong2, Fanhui Guo2, Xiaokai Chen2, Jianjun Wu2, Zhenyong Miao2   

  1. 1 National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou 221116, China;
    2 School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, China
  • 收稿日期:2018-03-08 修回日期:2018-05-22 出版日期:2018-07-28 发布日期:2018-08-16
  • 通讯作者: Jianjun Wu,E-mail address:jjuw@163.com
  • 基金资助:

    Supported by the National Natural Science Foundation of China (51704292, 51774285), the China Postdoctoral Science Foundation (2016M601919), the National Key R&D Program of China (2016YFB0600401) and the Fundamental Research Funds for the Central Universities (2017QNA25, CPEUKF1704).

Experimental study on the effects of drying methods on the stabilities of lignite

Yixin Zhang1, Jixiang Dong2, Fanhui Guo2, Xiaokai Chen2, Jianjun Wu2, Zhenyong Miao2   

  1. 1 National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou 221116, China;
    2 School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, China
  • Received:2018-03-08 Revised:2018-05-22 Online:2018-07-28 Published:2018-08-16
  • Contact: Jianjun Wu,E-mail address:jjuw@163.com
  • Supported by:

    Supported by the National Natural Science Foundation of China (51704292, 51774285), the China Postdoctoral Science Foundation (2016M601919), the National Key R&D Program of China (2016YFB0600401) and the Fundamental Research Funds for the Central Universities (2017QNA25, CPEUKF1704).

摘要: The drying processes are always applied prior to the transportation or utilization of lignite, and result in notable changes in the stabilities of lignite. In this paper, the study on the effects of nitrogen and MTE drying process on the physico-chemical properties and stabilities of Zhaotong lignite was carried out. The briquettes produced by MTE drying in this study were 150 mm in dimension, and so had a much larger particle size than nitrogendried samples. Nitrogen adsorption, mercury intrusion porosimetry and scanning electron microscopy all suggested that drying was accompanied by the transformation of larger pores into smaller ones. Compared to nitrogen drying, the pore structures could be stabilized by the MTE process. The soluble salts were removed during MTE drying which resulted in the decrease in ash and the concentrations of some of the major metals. The removal of water enhanced the hydrophilicity of nitrogen dried samples, but did not affect the hydrophilicity of MTE dried samples. The moisture holding capacity of MTE dried samples reduced faster than nitrogen dried samples with the decrease of residual moisture content. The moisture readsorption processes of MTE dried samples were strongly inhibited due to the much larger particle size of sample produced by MTE drying than nitrogen drying. The susceptibility to spontaneous combustion, indicated by cross point temperature and self-heating tests, of nitrogen and MTE dried samples increased with the decrease of residual moisture content. The MTE dried samples are more liable to spontaneous combustion than nitrogen dried samples with the same residual moisture and particle size. However, the larger particle size of the MTE product made it more stable with respect to spontaneous combustion and also moisture readsorption.

关键词: Lignite, Mechanical thermal expression, Stability, Hydrophilicity, Readsorption, Spontaneous combustion

Abstract: The drying processes are always applied prior to the transportation or utilization of lignite, and result in notable changes in the stabilities of lignite. In this paper, the study on the effects of nitrogen and MTE drying process on the physico-chemical properties and stabilities of Zhaotong lignite was carried out. The briquettes produced by MTE drying in this study were 150 mm in dimension, and so had a much larger particle size than nitrogendried samples. Nitrogen adsorption, mercury intrusion porosimetry and scanning electron microscopy all suggested that drying was accompanied by the transformation of larger pores into smaller ones. Compared to nitrogen drying, the pore structures could be stabilized by the MTE process. The soluble salts were removed during MTE drying which resulted in the decrease in ash and the concentrations of some of the major metals. The removal of water enhanced the hydrophilicity of nitrogen dried samples, but did not affect the hydrophilicity of MTE dried samples. The moisture holding capacity of MTE dried samples reduced faster than nitrogen dried samples with the decrease of residual moisture content. The moisture readsorption processes of MTE dried samples were strongly inhibited due to the much larger particle size of sample produced by MTE drying than nitrogen drying. The susceptibility to spontaneous combustion, indicated by cross point temperature and self-heating tests, of nitrogen and MTE dried samples increased with the decrease of residual moisture content. The MTE dried samples are more liable to spontaneous combustion than nitrogen dried samples with the same residual moisture and particle size. However, the larger particle size of the MTE product made it more stable with respect to spontaneous combustion and also moisture readsorption.

Key words: Lignite, Mechanical thermal expression, Stability, Hydrophilicity, Readsorption, Spontaneous combustion