Determination and kinetics analysis of coal ignition point based on thermal explosion method

doi:10.16265/j.cnki.issn1003-3033.2022.02.009

Abstract

Abstract:

In order to accurately decide ignition point of coal and improve prevention and control ability of spontaneous combustion disasters, according to TET and with consideration to heat release curve of spontaneous combustion process, the first minimum point on differential heat flow curve in the process was taken as ignition point, and dynamic parameters during heat release before and after ignition were calculated. The results show that along with increase in heating rate, exothermic process of coal spontaneous combustion gradually moves to high temperature regions, and ignition point also increases gradually, while activation energy of reaction decreases in the same manner. At the same heating rate, activation energy of coal increases after ignition, with the level of coal oxygen reaction being decreased to 1 after ignition point from 1.5 before it. It is also found that oxygen combustion of coal after ignition is more sufficient, and spontaneous combustion is more difficult to control.

Key words: thermal explosion theory(TET), ignition point, dynamics, coal spontaneous combustion, differential scanning calorimetry(DSC)

CHEN Xiaokun, WANG Chenxi, ZHAI Xiaowei. Determination and kinetics analysis of coal ignition point based on thermal explosion method[J]. China Safety Science Journal, 2022, 32(2): 59-65.

Figures/Tables 9

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煤种	工业分析
煤种	水分	灰分	挥发分	固定碳
不粘煤	4.21	7.73	36.31	51.75

升温速率	反应级数	燃点前		燃点后
升温速率	反应级数	拟合函数表达式	R²	拟合函数表达式	R²
5	0.5	y=81 309.55x+4.22	0.911 1	y=77 233.00x-0.98	0.924 8
	1	y=87 216.39x+5.73	0.932 4	y=99 228.46x+3.06	0.968 2
	1.5	y=94 344.36x+7.54	0.943 5	y=132 350.23x+9.11	0.936 4
	2	y=102 558.67x+9.62	0.939 4	y=173 579.29x+16.62	0.865 9
	2.5	y=11 606.71x+11.91	0.922 0	y=219 166.47x+24.91	0.807 5
	3	y=121 276.47x+14.36	0.896 5	y=267 219.99x+33.66	0.766 7
10	0.5	y=79 483.84x+3.33	0.940 1	y=74 366.62x-1.91	0.945 9
	1	y=85 320.08x+4.76	0.957 1	y=96 022.88x+1.95	0.984 0
	1.5	y=92 249.34x+6.46	0.964 5	y=12 7830.21x+7.58	0.956 4
	2	y=100 176.96x+8.42	0.958 9	y=167 316.43x+14.55	0.893 9
	2.5	y=108 904.77x+10.57	0.941 8	y=21 148.69x+22.29	0.840 2
	3	y=118 245.52x+12.88	0.917 5	y=257 489.20x+30.46	0.801 9
15	0.5	y=67 400.88x+0.69	0.895 1	y=73 372.21x-2.41	0.940 3
	1	y=71 593.32x+1.79	0.913 3	y=92 349.00x+0.93	0.980 4
	1.5	y=76 545.00x+3.05	0.923 2	y=121 747.90x+6.01	0.979 9
	2	y=82 215.07x+4.51	0.920 7	y=156 691.15x+12.07	0.949 7
	2.5	y=88 444.86x+6.13	0.906 3	y=195 659.65x+18.81	0.913 5
	3	y=95 098.05x+7.85	0.883 8	y=237 041.23x+25.98	0.88 24