物理化学学报 >> 2009, Vol. 25 >> Issue (12): 2597-2603.doi: 10.3866/PKU.WHXB20091218

研究论文 上一篇    下一篇

低煤级煤热解H2生成动力学及其与第一次煤化作用跃变的关系

李美芬, 曾凡桂, 孙蓓蕾, 齐福辉   

  1. 太原理工大学地球科学与工程系, 煤科学与技术教育部及山西省重点实验室, 太原 030024
  • 收稿日期:2009-06-18 修回日期:2009-08-17 发布日期:2009-11-27
  • 通讯作者: 曾凡桂 E-mail:zengfangui@tyut.edu.cn

Evolution Kinetics of Hydrogen Generation from Low Rank Coal Pyrolysis and Its Relation to the First Coalification Jump

LI Mei-Fen, ZENG Fan-Gui, SUN Bei-Lei, QI Fu-Hui   

  1. Key Laboratory of Coal Science&Technology of Ministry of Education & Shanxi Province, Department of Earth Science & Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
  • Received:2009-06-18 Revised:2009-08-17 Published:2009-11-27
  • Contact: ZENG Fan-Gui E-mail:zengfangui@tyut.edu.cn

摘要:

用开放体系的热重-质谱联用仪(TG/MS)研究了7种低煤级煤的热解特征、H2的生成动力学特征以及它们与第一次煤化作用跃变的关系. 结果显示, 煤热解失重率在碳含量(Cdaf)为80%(质量分数)和镜质组最大反射率(R0max)为0.60%附近发生转折; 氢气生成的特征温度参数以及动力学参数均在Cdaf为80%(R0max为0.60%)左右表现为最低; 氢气的总产率在此处最大. 这些特征参数的极值点刚好与第一次煤化作用跃变点一致, 说明这些参数可以反映第一次煤化作用跃变的发生. 结合傅立叶变换红外(FTIR)光谱法获得的煤结构特征, 对影响机制进行了分析解释, 认为是由以下3个方面的原因导致的: (1)煤中脂肪类含氧官能团的演化特征; (2)可溶有机质的低温热缩聚作用; (3)有机质的“两极分化”作用.

关键词: 氢气, 煤热解, 动力学, 煤化作用跃变, 热缩聚反应, 两极分化

Abstract:

The open system pyrolysis characteristics of 7 low rank coals and the evolution kinetics of H2 and its relation to the first coalification jump were determined using a thermogravimetric analyzer coupled to a quadrupole mass spectrometer (TG/MS). Results showed that both the coal pyrolysis characteristics and the evolution kinetics of H2 are strongly related to the first coalification jump, which is demonstrated by three aspects: the weight loss rate indicates an abrupt change at Cdaf=80%(R0max =0.60%) (Cdaf is carbon content (mass fraction) of sample in dry-ash-free basis, R0max is the maximum reflectance of vitrinite in coal); the characteristic temperatures and kinetic parameters of H2 exhibit a minimumvalue at Cdaf=80% (R0max =0.60%); the total yield of hydrogen had a maximum value at Cdaf=80% (R0max=0.60%) and this is consistent with the initial point of the first coalification jump. These aspects indicate that the derived parameters can reveal the first coalification jump. Combined with the structural characterization of the coals by FTIR, a mechanismthat explains the results was determined using the following three factors: (1) the evolution characteristics of aliphatic oxygen-containing functional groups; (2) the retrogressive reaction of soluble organic matter and (3) the "polarization" of organic matter.

Key words: Hydrogen, Coal pyrolysis, Kinetics, Coalification jump, Retrogressive reaction, Polarization

MSC2000: 

  • O643