Heat effects of pyrolysis of 15 acid washed coals in a DSC/TGA-MS system

被引:25
作者
Cheng, Xiaojie [1 ]
Shi, Lei [1 ]
Liu, Qingya [1 ]
Liu, Zhenyu [1 ]
机构
[1] Beijing Univ Chem Technol, State Key Lab Chem Resource Engn, Beijing 100029, Peoples R China
关键词
Coal; Pyrolysis; DSC; TG; Radicals; DIFFERENTIAL SCANNING CALORIMETRY; CROSS-LINKING REACTIONS; THERMAL-ANALYSIS; METAL CHLORIDES; MINERAL MATTER; BEHAVIOR; DISSOLUTION; COMBUSTION; DEPENDENCE; KINETICS;
D O I
10.1016/j.fuel.2020.117325
中图分类号
TE [石油、天然气工业]; TK [能源与动力工程];
学科分类号
0807 ; 0820 ;
摘要
Heat effects of coal pyrolysis are seldomly studied in the past and the few studies available in the literature differ from each other. The problem perhaps arises from the unclear definition of thermal steady state of differential scanning calorimetry (DSC), the different effects of minerals in coals, and the different mass bases used to quantify the heat flows. This work studies the heat effects during pyrolysis of 15 acid washed coals (D-coals), ranked from lignite to anthracite, in the temperature range of 117-900 degrees C in a system that couples DSC with a thermal gravimetric analyzer (TGA) and a mass spectrometer (MS). The steady state criteria of DSC are studied. The heat effects studied include the total pyrolysis heat (sensible heat + reaction heat) and the reaction heat. It is found that the time needed to reach the steady state for DSC is longer than that for TGA. The in situ char pyrolysis following the coal pyrolysis involves mass loss and reaction heat, so its profile should not be used to estimate the thermal capacity of coal. The reaction heat on DTG basis (q(r-DTG)) correlates better with C% of coals than that on the initial coal basis, both of them are endothermic in the temperature range of < 560 degrees C and turn to exothermic at higher temperatures. It is also found that the major endothermic q(r-DTG) occurs prior to the main DTG peak; the major exothermic q(r-DTG) occurs upon the completion of the main DTG peak, about 130 degrees C higher than the DTG peak temperature; the radical concentration of char increases with increasing temperature during the evolution of the main DTG peak, but starts to decrease at the completion of the main DTG peak, around 600 degrees C, and then diminishes at around 750 degrees C.
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页数:10
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共 37 条
  • [1] Effect of a HF-HF/HCl Treatment of 26 Coals on Their Composition and Pyrolysis Behavior
    Cheng, Xiaojie
    Shi, Lei
    Liu, Qingya
    Liu, Zhenyu
    [J]. ENERGY & FUELS, 2019, 33 (03) : 2008 - 2017
  • [2] THERMOGRAVIMETRY AND DIFFERENTIAL SCANNING CALORIMETRY OF KENTUCKY BITUMINOUS COALS
    ELDER, JP
    BENHARRIS, M
    [J]. FUEL, 1984, 63 (02) : 262 - 267
  • [3] NATURE OF POROSITY IN AMERICAN COALS
    GAN, H
    WALKER, PL
    NANDI, SP
    [J]. FUEL, 1972, 51 (04) : 272 - &
  • [4] Glass HerbertDavid., 1954, Economic Geology, V49, P294, DOI DOI 10.2113/GSECONGEO.49.3.294
  • [5] Behaviors of radical fragments in tar generated from pyrolysis of 4 coals
    He, Wenjing
    Liu, Zhenyu
    Liu, Qingya
    Ci, Donghui
    Lievens, Caroline
    Guo, Xiaofen
    [J]. FUEL, 2014, 134 : 375 - 380
  • [6] CALORIMETRIC PYROLYSIS OF A NORTH-DAKOTA LIGNITE
    HEFTA, RS
    SCHOBERT, HH
    KUBE, WR
    [J]. FUEL, 1986, 65 (09) : 1196 - 1202
  • [7] REACTIONS OF OXYGEN CONTAINING STRUCTURES IN COAL PYROLYSIS
    HODEK, W
    KIRSCHSTEIN, J
    VANHEEK, KH
    [J]. FUEL, 1991, 70 (03) : 424 - 428
  • [8] Practical estimation of reaction heat during the pyrolysis of cedar wood
    Hosokai, Sou
    Matsuoka, Koichi
    Kuramoto, Koji
    Suzuki, Yoshizo
    [J]. FUEL PROCESSING TECHNOLOGY, 2016, 154 : 156 - 162
  • [9] FUNCTIONAL-GROUP DEPENDENCE OF CROSS-LINKING REACTIONS DURING PYROLYSIS OF COAL
    IBARRA, JV
    MOLINER, R
    GAVILAN, MP
    [J]. FUEL, 1991, 70 (03) : 408 - 413
  • [10] PYROLYSIS AND COMBUSTION STUDIES OF FOSSIL-FUELS BY THERMAL-ANALYSIS METHODS
    KOK, MV
    PAMIR, MR
    [J]. JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS, 1995, 35 (02) : 145 - 156