Effect of initial pressures on lower explosion limits of syngas

doi:10.16265/j.cnki.issn1003-3033.2022.08.1555

Abstract

Abstract:

The lower explosion limit (LEL) of syngas under different initial pressures was measured by 8 L cylindrical explosion tank. The effect of initial pressure on the near-low limit combustion of syngas was simulated by Chemkin-Pro software, and the applicability of Le Chatelier (L-C) calculation formula, quadratic polynomial, linear and logarithmic function fitting relationship to the LEL of pressurized syngas with wide hydrogen content ratio was checked. The experimental results show that the LEL of syngas decreases with the increase of H₂ content ratio, and decreases linearly with the increase of initial pressure. Under the high pressure condition, the mole fraction of H radical and OH radical changed, resulting in the change of the sensitivity coefficient of important branched-chain reactions such as H+O₂=O+OH, which further reduced the LEL of syngas. Compared with the L-C calculation formula, the quadratic polynomial is more accurate in estimating the LEL of syngas under high pressure. Furthermore, the linear function relationship can accurately calculate the syngas LEL under different initial pressures.

Key words: initial pressure, syngas, lower explosion limits(LEL), hydrogen ratio, Le Chatelier(L-C) formula

SHANG Rongxue, ZHUANG Zixuan, YANG Yue, NIU Jiangyu, LI Gang. Effect of initial pressures on lower explosion limits of syngas[J]. China Safety Science Journal, 2022, 32(8): 120-125.

Figures/Tables 9

Fig.1

Tab.1

LEL of syngas with different x H 2%

$x H 2$	P /MPa
$x H 2$	0.1	0.2	0.3
0	12.77	12.13	11.65
0.25	8.28	7.90	7.23
0.50	6.48	5.54	5.11
0.75	5.09	4.88	4.23
1.00	4.22	3.95	3.13

Tab.1

Fig.2

Fig.3

Fig.4

Fig.5

Fig.6

Tab.2

Linear fitting of experimental data

$x H 2$	表达式	R²
0	LEL=-5.6P+13.30	0.993 2
0.25	LEL=-5.3P+8.85	0.975 2
0.50	LEL=-6.9P+7.08	0.955 9
0.75	LEL=-4.3P+5.59	0.919 7
1.00	LEL=-5.5P+4.74	0.992 0

Tab.2

Tab.3

Logarithmic fitting of experimental data

$x H 2$	表达式	R²
0	LEL=-2.32lg(10P) +12.79	0.995 4
0.25	LEL=-2.10lg(10P) +8.35	0.908 0
0.50	LEL=-2.90lg(10P) +6.46	0.996 2
0.75	LEL=-1.68lg(10P) +5.17	0.820 7
1.00	LEL=-2.26lg(10P) +4.23	0.996 4

Tab.3

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