月桂酸与硬脂酸粉尘爆炸过程热解动力学与火焰传播特性关系

张延松; 李南; 郭瑞; 张新燕; 张公妍; 黄兴旺

doi:10.11883/bzycj-2021-0470

月桂酸与硬脂酸粉尘爆炸过程热解动力学与火焰传播特性关系

doi: 10.11883/bzycj-2021-0470

张延松^1,,
李南¹,
郭瑞¹,
张新燕^{1, 2, ,},
张公妍¹,
黄兴旺¹

1.
山东科技大学安全与环境工程学院，山东青岛 266590
2.
山东科技大学矿山灾害预防控制省部共建国家重点实验室培育基地，山东青岛 266590

基金项目: 国家自然科学基金（51904170）；山东省自然科学基金（ZR2018BEE006）

详细信息

作者简介:
张延松（1964－　），男，博士，教授，zys6407@126.com

通讯作者:
张新燕（1987－　），女，博士，副教授，xyzhang_safety@sdust.ecu.cn

中图分类号: O383; X932
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- 被引次数: 0
出版历程
- 收稿日期: 2021-11-10
- 修回日期: 2021-12-23
- 网络出版日期: 2022-06-09
- 刊出日期: 2022-07-25

Relationship between pyrolysis kinetics and flame propagation characteristics of lauric acid and stearic acid dust explosion

1.
Institute of Safety and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590, Shandong, China
2.
State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of the Science and Technology, Shandong University of Science and Technology, Qingdao 266590, Shandong, China

摘要

摘要: 综合应用同步热分析仪、改进的哈特曼爆炸测试装置及高速摄影系统，对月桂酸与硬脂酸粉尘的热解氧化特性及其在半封闭竖直管道内的火焰传播特性开展了实验研究，并分析讨论了月桂酸与硬脂酸粉尘爆炸燃烧过程中热解动力学与火焰传播特性的关系。结果表明，当粉尘云质量浓度为125 g/m³时，月桂酸粉尘云的火焰锋面结构比硬脂酸平滑，但硬脂酸粉尘的火焰传播速度明显大于月桂酸；随着质量浓度的增加，月桂酸和硬脂酸粉尘的火焰前锋逐渐变得离散，火焰传播速度逐渐增加，但速度差值逐渐减小；月桂酸粉尘的平均火焰传播速度在750 g/m³的粉尘云质量浓度下高于硬脂酸，火焰结构连续性显着降低。低质量浓度条件下月桂酸与硬脂酸粉尘云火焰传播特性差异主要由快速热解阶段的氧化放热特性决定，指前因子越大，参与热解和氧化反应的活性中心越多，氧化放热量越大，放热速率越快，火焰传播速度越快，火焰锋面结构由光滑连续向不规则离散的转变越快。随着粉尘云质量浓度的增加，火焰传播特性差异逐渐由活化能及火焰前锋预热区内氧气的质量输运过程控制，活化能越大，耗氧量越大，耗氧速率越快，越易导致火焰传播速度下降，火焰锋面趋于复杂，火焰结构连续性降低。
- 粉尘爆炸 /
- 月桂酸 /
- 硬脂酸 /
- 热解动力学 /
- 火焰传播
Abstract: The pyrolysis and oxidation characteristics and flame propagation characteristics in the semi-enclosed vertical pipe of lauric acid dust and stearic acid dust were studied by using the synchrotron thermal analyzer, improved Hartmann explosive test device and high-speed photography system, the pyrolysis kinetics was analyzed by Coats-Redfern method to obtain the kinetic parameters, and the influence of pyrolysis and oxidation characteristics on the law of flame propagation during the explosion and combustion of lauric acid and stearic acid dust was analyzed and discussed. The results show that, when the dust cloud concentration is 125 g/m³, the flame front structure of lauric acid dust cloud is smoother than stearic acid dust, but the flame propagation speed of stearic acid dust is significantly greater than that of lauric acid dust; with the increase of dust cloud concentration, the flame front structure of lauric acid dust and stearic acid dust gradually becomes discrete, and the flame propagation speed gradually increases, but the speed difference gradually decreases. The average flame propagation speed of lauric acid dust is higher than that of stearic acid dust at a dust cloud concentration of 750 g/m³, and the flame structure continuity is significantly reduced. The difference in flame propagation between lauric acid dust and stearic acid dust at low concentrations is mainly determined by the oxidation exothermic characteristics of the fast pyrolysis stage. The larger the pre-exponential factor, the more active sites involved in the pyrolysis and oxidation reactions, the larger the oxidation exothermic heat, the faster the exothermic rate, the faster the flame propagation speed, and the faster the flame frontal structure transition from smooth continuous to discrete complex. And with the increase of dust cloud concentration, the flame propagation difference is gradually controlled by the activation energy and the mass transport process of oxygen in the preheating zone of the flame front. The greater the activation energy, the greater the oxygen consumption, the faster the oxygen consumption rate, the easier it will lead to the decrease of flame propagation speed, the more complex the flame front, and the decrease of flame structure continuity.
- dust explosion /
- lauric acid /
- stearic acid /
- pyrolysis kinetics /
- flame propagation

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图 1 月桂酸和硬脂酸的粉尘粒度分布

Figure 1. Particle size distribution of lauric acid and stearic acid dust

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图 2 月桂酸与硬脂酸粉尘的扫描电子显微镜图像

Figure 2. Scanning electron microscope images of lauric acid and stearic acid dusts

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图 3 同步热分析仪装置示意图

Figure 3. Schematic diagram of synchronous thermal analyzer device

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图 4 改进的哈特曼管实验装置

Figure 4. Schematic of the improved Hartmann tube experimental device

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图 5 不同升温速率下月桂酸粉尘和硬脂酸粉尘的热特性曲线

Figure 5. Thermal curves of lauric acid and stearic acid dust at different heating rates

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图 6 粉尘云质量浓度125 g/m³条件下月桂酸和硬脂酸粉尘的火焰传播过程

Figure 6. Flame propagation processes of lauric acid and stearic acid dusts at the dust cloud concentration of 125 g/m³

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图 7 粉尘云质量浓度375 g/m³条件下月桂酸和硬脂酸粉尘的火焰传播过程

Figure 7. Flame propagation processes of lauric acid and stearic acid dusts at the dust cloud concentration of 375 g/m³

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图 8 粉尘云质量浓度500 g/m³条件下月桂酸和硬脂酸粉尘的火焰传播过程

Figure 8. Flame propagation processes of lauric acid and stearic acid dusts at the dust cloud concentration of 500 g/m³

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图 9 粉尘云质量浓度750 g/m³条件下月桂酸和硬脂酸粉尘的火焰传播过程

Figure 9. Flame propagation processes of lauric acid and stearic acid dusts at the dust cloud concentration of 750 g/m³

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图 10 不同质量浓度条件下月桂酸与硬脂酸粉尘云火焰传播速度

Figure 10. Comparison of flame propagation speeds between lauric acid and stearic acid dusts at different dust cloud concentrations

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表 1 月桂酸和硬脂酸的粉尘粒度分布特征参数

Table 1. Particle size distribution characteristic parameters of lauric acid and stearic acid dusts

材料	比表面积S/(m²·g⁻¹)	表面积平均径D_[3,2]/µm	体积平均径D_[4,3]/µm	中位粒径D₅₀/µm
月桂酸	0.42	14.29	37.55	33.97
硬脂酸	0.46	12.97	35.86	30.71

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表 2 运用Coats-Redfern法求解的月桂酸和硬脂酸动力学参数^[8]

Table 2. Kinetic parameters of lauric acid and stearic acid dusts by the Coats-Redfern method^[8]

样品	升温速率/(℃·min⁻¹)	快速热解阶段			慢速热解阶段
样品	升温速率/(℃·min⁻¹)	活化能/(kJ·mol⁻¹)	指前因子/min	机理函数	活化能/(kJ·mol⁻¹)	指前因子/min	机理函数
月桂酸	5	24.44	26726	D1	14.65	13.64	F1.5
	10	26.34	44451	D1	21.53	14.14	F1.5
	15	27.40	92412	D1	19.73	116.39	F1.5
	平均值	26.06	54530		18.64	48.06
硬脂酸	5	26.86	29497	F1.5	29.03	433.84	D3
	10	28.57	89067	F1.5	31.53	1383.00	D3
	15	30.50	126670	F1.5	28.15	777.12	D3
	平均值	28.64	81745		29.57	864.65

下载: 导出CSV

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