分散度对煤粉爆炸特性的影响
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摘要
煤矿工作面煤尘呈多分散性,因此采用单一粒径的煤样评估煤尘爆炸风险存在缺陷。为了研究分散度对煤尘爆炸特性的影响规律,找出合适的平均粒径表示方式来评估分散度对爆炸风险的影响,以5种粒径分布范围相同但分散度不同的煤样为研究对象,采用20 L爆炸球实验装置,测量样品的最大爆炸压力P_(ex)、最大爆炸压力上升速率(dp/dt)_(ex)、开始点火至最大爆炸压力的时间段t_1和开始点火至最大爆炸压力上升速率的时间段t_2四个参数。后续采用热值分析、扫描电镜试验方法探究不同分散度煤尘的反应程度。借助方差分析和斯皮尔曼相关性分析研究测量结果组间的差异性、不同粒径表示方式与爆炸特性参数的相关性。实验结果表明:对于具有相同粒径分布的煤粉,分散度对煤粉爆炸反应速率影响较大。小粒径煤尘颗粒的质量分数越大,反应速率越快,反应越充分,释放的能量越大。当小粒径煤尘质量分数达到30%时,最大爆炸压力上升速率显著增大,t_1和t_2明显减小。粒径最小的原始样品3的爆炸产物热值最低,且爆炸产物表面形成了较为丰富的孔洞结构,说明小粒径煤尘较快的脱挥发速率能增加爆炸的反应程度。D_(10),D_(25)(为投影面积的10%和25%的颗粒直径)、D_(3,2)(索特尔直径)与最大爆炸压力上升速率、t_1和t_2三个参数的斯皮尔曼相关系数均落在高度相关和显著相关的区间,呈现出较好的相关性。对于多分散性的煤尘,D_(10),D_(25)和D_(3,2)可以较好的评估分散度对煤尘爆炸特性的影响。
The coal dust is polydisperse in the coalface of longwall mining. Thus,the evaluation of the explosion risk of coal dust by single particle size is defective. In order to investigate the effect of dispersion on the characteristics of coal dust explosions and find the appropriate expressive ways of average particle size to estimate the explosion risk, five coal samples with the same particle size distribution range whereas with different dispersions were investigated. The 20 L explosion sphere vessels experimental device was used to measure four parameters of the sample, including the maximum explosion pressure(P_(ex)), the maximum explosion pressure rise rate((dp/dt)_(ex)), the period from the ignition to the maximum explosion pressure(t_1), and the period from the ignition to the maximum explosion pressure rise rate(t_2). Calorific value analysis and scanning electron microscopy were used to investigate the degree of reaction of coal dust with different dispersions. The diversities between the measurement results of different groups were investigated by the analysis of variance. The correlation between various particle size representation methods and the explosion characteristics parameters were investigated by Spearman correlation analysis. The experimental results showed that the dispersity had a great significant influence on the explosion reaction rate of coal dust with the same particle size span. The larger the mass fraction of small coal dust particle size is, the faster the reaction rate, the more complete the reaction and released energy. When the small particles accounted for 30%,the(dp/dt)_(ex) increased significantly,t_1 and t_2 decreased significantly. The explosive products of the original sample 3 with small particle size had the lowest calorific value and rich pore structures on the particles surfaces, which could proved that the explosion reaction degree of the finer coal dust can be increased due to the accelerating devolatilization rate. The Spearman correlation coefficients between D_(10),D_(25)(the particle size for which 10% and 25% of the particles by the projection area),D_(3,2)(Sauter mean diameter) and(dp/dt)_(ex),t_1,t_2 fall within highly-correlated and significantly-correlated intervals. It showed a good correlation. D_(10),D_(25) and D_(3,2) are the appropriate methods to describe the dispersion of polydisperse coal dust for investigating the explosions.
The coal dust is polydisperse in the coalface of longwall mining. Thus,the evaluation of the explosion risk of coal dust by single particle size is defective. In order to investigate the effect of dispersion on the characteristics of coal dust explosions and find the appropriate expressive ways of average particle size to estimate the explosion risk, five coal samples with the same particle size distribution range whereas with different dispersions were investigated. The 20 L explosion sphere vessels experimental device was used to measure four parameters of the sample, including the maximum explosion pressure(P_(ex)), the maximum explosion pressure rise rate((dp/dt)_(ex)), the period from the ignition to the maximum explosion pressure(t_1), and the period from the ignition to the maximum explosion pressure rise rate(t_2). Calorific value analysis and scanning electron microscopy were used to investigate the degree of reaction of coal dust with different dispersions. The diversities between the measurement results of different groups were investigated by the analysis of variance. The correlation between various particle size representation methods and the explosion characteristics parameters were investigated by Spearman correlation analysis. The experimental results showed that the dispersity had a great significant influence on the explosion reaction rate of coal dust with the same particle size span. The larger the mass fraction of small coal dust particle size is, the faster the reaction rate, the more complete the reaction and released energy. When the small particles accounted for 30%,the(dp/dt)_(ex) increased significantly,t_1 and t_2 decreased significantly. The explosive products of the original sample 3 with small particle size had the lowest calorific value and rich pore structures on the particles surfaces, which could proved that the explosion reaction degree of the finer coal dust can be increased due to the accelerating devolatilization rate. The Spearman correlation coefficients between D_(10),D_(25)(the particle size for which 10% and 25% of the particles by the projection area),D_(3,2)(Sauter mean diameter) and(dp/dt)_(ex),t_1,t_2 fall within highly-correlated and significantly-correlated intervals. It showed a good correlation. D_(10),D_(25) and D_(3,2) are the appropriate methods to describe the dispersion of polydisperse coal dust for investigating the explosions.
引文
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[10] DUFAUD 0,TRAORE M,PERRIN L,et al. Experimental investigation and modelling of aluminum dusts explosions in the 20 L sphere[J]. Journal of Loss Prevention in the Process Industries.2010,23(2):226-236.
[11] LI Qingzhao, WANG Ke,ZHENG Yuanna,et al. Experimental research of particle size and size dispersity on the explosibility characteristics of coal dust[J]. Powder Technology, 2016,292(9):290-297.
[12] GB/T 212—2008,煤的工业分析方法[S].GB/T 212—2008,Industrial analysis method of coal[S].
[13]崔克清.安全工程大辞典[M].北京:化学工业出版社,1995:295.
[14] WANG D, FAN L S. Particle characterization and behavior relevant to fluidized bed combustion and gasification systems[M]. London:Woodhead Publishing,2013:42-76.
[15] GB/T 16426—1996,粉尘云最大爆炸压力和最大压力上升速率测定方法[S].GB/T 16426—1996, Dust cloud maximum explosion pressure and maximum pressure rise rate determination method[S].
[16] GB/T 213-2008,煤的发热量测定方法[S].GB/T 213—2008, Method for measuring calorific value of coal[S].
[17]胡松,孙学信,邹祖桥,等.煤燃烧过程中颗粒表面的特性[J].自然科学进展,2002(2):77-81.HU Song,SUN Xuexin,ZOU Zuqiao,et al. Characteristics of particle surface during coal combustion[J]. Natural Science Progress,2002(2):77-81.
[18]庞磊,马冉,高建村,等.粉尘云浓度对HDPE粉尘云最低着火温度的影响[J].中国安全生产科学技术,2017,13(5):5-9.PANG Lei,MA Ran, GAO Jiancun,et al. Effect of concentration of dust cloud on minimum ignition temperature of HDPE dust cloud[J]. Journal of Safety Science and Technology,2017,13(5):5-9.
[19]万杭炜,赵江平.基于响应面法的木粉尘最大爆炸压力试验研究-以桑木粉尘为例[J].中国安全生产科学技术,2017,13(6):173-178.WAN Hangwei,ZHAO Jiangping. Experimental study on maximum explosion pressure of wood dust based on response surface methodTaking mulberry wood dust as example[J]. Journal of Safety Science and Technology,2017,13(6):173-178.
[20] YUZURIHA Y,GAO Wei,MOGI T,et al. Effects of particle size distributions on flame propagation behavior through dust clouds of PMMA[J]. Journal of Loss Prevention in the Process Industries,2017,(49):852-858.
[21]ADDAI E K, GABLE D, KRAUSE U. Experimental investigation on the minimum ignition temperature of hybrid mixtures of dusts and gases or solvents[J]. Journal of Hazardous Materials,2016,301(6):314-326.
[2]李庆钊,翟成,吴海进,等.基于20 L球形爆炸装置的煤尘爆炸特性研究[J].煤炭学报,2011,36(1):119-124.LI Qingzhao, ZHAI Cheng, WU Haijin, et al. Investigation on coal dust explosion characteristics using 20 L explosion sphere vessels[J]. Journal of China Coal Society,2011,36(1):119-124.
[3] ZHANG Jiangshi,XU Peihui,SUN Longhao,et al. Factors influencing and a statistical method for describing dust explosion parameters:A review[J]. Journal of Loss Prevention in the Process Industries,2018,56(6):386-401.
[4] BOUILLARD J,VIGNES A,DUFAUD 0,et al. Ignition and explosion risks of nanopowders[J]. Journal of Hazardous Materials,2010,181(1):873-880.
[5] GAO Wei,MOGI T,Sun Jinhua,et al. Effects of particle size distributions on flame propagation mechanism during octadecanol dust explosions[J]. Powder Technol,2013,249(9):168-174.
[6] LI Qingzhao, WANG Ke,ZHENG Yuanna,et al. Explosion severity of micro-sized aluminum dust and its flame propagation properties in20 L spherical vessel[J]. Powder Technology, 2016, 301(1):1299-1308.
[7]GU Mingyan,CHEN Xue,WU Cengceng,et al. Effects of particle size distribution and oxygen concentration on the propagation behavior of pulverized coal flames in 02/C02 Atmospheres[J]. Energy&Fuels,2017,31(5):5571-5580.
[8]武层层,顾明言,李红,等.O_2/CO_2气氛下煤粉粒径分布对火焰传播的影响[J].安徽工业大学学报(自科版),2016,33(3):205-209.WU Cengceng,GU Mingyan,LI Hong,et al. Effect of pulverized coal particle size distribution on flame propagation in O_2/CO_2 atmosphere[J]. Journal of AnHui University of Technology,2016,33(3):205-209.
[9] CASTELLANOS D,CARRETO-VAZQUEZ V H,MASHUGA C V,et al. The effect of particle size polydispersity on the explosibility characteristics of aluminum dust[J]. Powder Technology, 2014,254(2):331-337.
[10] DUFAUD 0,TRAORE M,PERRIN L,et al. Experimental investigation and modelling of aluminum dusts explosions in the 20 L sphere[J]. Journal of Loss Prevention in the Process Industries.2010,23(2):226-236.
[11] LI Qingzhao, WANG Ke,ZHENG Yuanna,et al. Experimental research of particle size and size dispersity on the explosibility characteristics of coal dust[J]. Powder Technology, 2016,292(9):290-297.
[12] GB/T 212—2008,煤的工业分析方法[S].GB/T 212—2008,Industrial analysis method of coal[S].
[13]崔克清.安全工程大辞典[M].北京:化学工业出版社,1995:295.
[14] WANG D, FAN L S. Particle characterization and behavior relevant to fluidized bed combustion and gasification systems[M]. London:Woodhead Publishing,2013:42-76.
[15] GB/T 16426—1996,粉尘云最大爆炸压力和最大压力上升速率测定方法[S].GB/T 16426—1996, Dust cloud maximum explosion pressure and maximum pressure rise rate determination method[S].
[16] GB/T 213-2008,煤的发热量测定方法[S].GB/T 213—2008, Method for measuring calorific value of coal[S].
[17]胡松,孙学信,邹祖桥,等.煤燃烧过程中颗粒表面的特性[J].自然科学进展,2002(2):77-81.HU Song,SUN Xuexin,ZOU Zuqiao,et al. Characteristics of particle surface during coal combustion[J]. Natural Science Progress,2002(2):77-81.
[18]庞磊,马冉,高建村,等.粉尘云浓度对HDPE粉尘云最低着火温度的影响[J].中国安全生产科学技术,2017,13(5):5-9.PANG Lei,MA Ran, GAO Jiancun,et al. Effect of concentration of dust cloud on minimum ignition temperature of HDPE dust cloud[J]. Journal of Safety Science and Technology,2017,13(5):5-9.
[19]万杭炜,赵江平.基于响应面法的木粉尘最大爆炸压力试验研究-以桑木粉尘为例[J].中国安全生产科学技术,2017,13(6):173-178.WAN Hangwei,ZHAO Jiangping. Experimental study on maximum explosion pressure of wood dust based on response surface methodTaking mulberry wood dust as example[J]. Journal of Safety Science and Technology,2017,13(6):173-178.
[20] YUZURIHA Y,GAO Wei,MOGI T,et al. Effects of particle size distributions on flame propagation behavior through dust clouds of PMMA[J]. Journal of Loss Prevention in the Process Industries,2017,(49):852-858.
[21]ADDAI E K, GABLE D, KRAUSE U. Experimental investigation on the minimum ignition temperature of hybrid mixtures of dusts and gases or solvents[J]. Journal of Hazardous Materials,2016,301(6):314-326.
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