甲烷含量对塑料粉尘空气混合物爆炸特性的影响

为探究可燃气体的添加对塑料粉尘/空气混合物爆炸特性的影响,以聚甲基丙烯酸甲酯(PMMA)和热塑性聚氨酯弹性体(TPU)2种塑料粉尘为研究对象,在对其进行热重分析(TG)的基础上,利用20 L球形爆炸试验装置,研究甲烷体积分数对这2种塑料粉尘/空气混合物爆炸压力、爆炸压力上升速率、爆炸下限等特征参数的影响。热重试验结果表明:PMMA粉体分解速率高,在外界供热条件下易发生燃烧,而TPU粉体分解所需能量更多,分解更加困难。爆炸试验结果表明:在试验选定的粉尘浓度条件下,2种粉尘爆炸压力及压力上升速率均随粉尘浓度呈现先升高后降低的变化趋势;当甲烷体积分数从0增加到4%时,塑料粉尘爆炸的猛度和敏感度随之增加,其中PMMA粉尘爆炸猛度受甲烷影响更大,而TPU粉尘基本不受影响,但其爆炸下限下降更明显。     

叶红素干渣爆炸特性实验研究

为研究叶红素干渣的爆炸特性,在对样品进行表观形态及粒径分布测试的基础上,开展了爆炸下限、最大爆炸压力和最大爆炸压力上升速率等参数的研究,并进行了热重分析。结果表明,粒径较小的叶红素干渣510B拥有更低的爆炸下限浓度;随着粉尘浓度的增加,两种样品的最大爆炸压力和最大爆炸压力上升速率曲线均呈现先升高后降低的趋势;510B在爆炸过程中的热分解反应更快、更充分,具有更高的最大爆炸压力和最大爆炸压力上升速率。     

泄压点火不同端管道内甲烷爆炸特性数值模拟

结合气体爆炸传播机理,利用FLACS软件对泄压点火不同端两种方式(泄压口通径为25 mm和泄压口完全开放)下甲烷的爆炸过程进行数值模拟,获得了5种体积分数甲烷的爆炸特性参数,分析得出:两种不同泄压方式下,10%,9.5%,11%体积分数的甲烷爆炸特性变化趋势接近,7%,8%的甲烷较前三者有所延迟;5种甲烷在管道中心处的最大爆炸压力、最大爆炸压力上升速率、最大爆炸压力下降速率、温度峰值都随甲烷体积分数的增大而逐渐上升,在10%时达到最大,继续增加甲烷体积分数则出现下降趋势,最大爆炸压力时间变化趋势与其相反;管道中心处的爆炸产物浓度随着甲烷体积分数的增大而增大,与泄压方式无关;增大管道泄压口面积有利于爆炸压力以及爆炸高温高压气体的释放,使得各体积分数甲烷的最大爆炸压力、最大爆炸压力上升速率、最大爆炸压力下降速率、温度峰值均下降,到达最大爆炸压力的时间均增大。     

谷物粉尘爆炸特性试验研究

为了解国内某啤酒企业平筛工艺过程除尘系统新鲜谷物粉尘爆炸特性,采用1.2 L哈特曼管式粉尘爆炸试验装置进行试验,以研究其粉尘粒径、质量浓度、含水率因素对谷物粉尘爆炸压力(P)及爆炸压力上升速率(d P/dt)的影响。结果表明,该谷物粉尘爆炸下限(LEL)质量浓度为125~166.67 g/m~3,质量浓度为291.67g/m~3时存在最大爆炸压力P_(max)和最大爆炸压力上升速率(d P/dt)max,分别为1.81 MPa和10 MPa/s;d P/dt与P变化具有相似性。谷物粉尘粒径由98~105μm增加至180~1 250μm,其LEL质量浓度由50~58.33 g/m~3增加至141.67~150 g/m~3,且P由0.90 MPa降低至0.72 MPa;含水率由6.39%降低至0(绝对干燥)时,P由1.3 MPa增加至2.1 MPa。     

含NaCl超细水雾抑制甲烷爆炸实验研究

为研究含NaCl添加剂超细水雾对甲烷爆炸的影响,在自制的半封闭透明管道内,进行含NaCl添加剂超细水雾抑制甲烷爆炸试验,通过检测和分析在不同NaCl浓度情况下超细水雾的粒径和甲烷爆炸的平均火焰传播速度、爆炸超压以及平均升压速率,探究NaCl浓度对超细水雾粒径及其对抑制甲烷爆炸有效性的影响。研究结果表明:NaCl浓度对超细水雾粒径影响较小;对于体积分数为9.5%的甲烷,相比于纯甲烷爆炸,其平均火焰传播速率、最大爆炸超压以及平均升压速率分别下降了53.7%,63.4%和60.7%,相比于超细纯水雾,其平均火焰传播速率、最大爆炸超压以及平均升压速率分别下降了38.6%,58%,56%;在通雾量相同的条件下,浓度为2.5%NaCl超细水雾对体积分数为9.5%的甲烷爆炸抑制性能最佳;含NaCl添加剂超细水雾的物理化学共同作用可以有效抑爆甲烷。     

甲烷-煤尘复合体系中煤尘爆炸下限的实验研究

在3.2 L的燃烧管道中,采用小能量的高压点火装置,通过改变甲烷体积分数、煤尘种类与粒径,研究了甲烷-煤尘复合体系中煤尘爆炸下限的变化规律.研究结果表明,在本文实验条件下,甲烷-煤尘混合物中甲烷体积分数的增加能明显降低煤尘的爆炸下限.对于煤尘粒径小于42 μm煤样A,当甲烷体积分数从1.8%增加到2.2%时,煤尘的爆炸下限相应从30 g/m3下降到6.25 g/m3.煤尘的爆炸下限也随着煤尘中挥发分含量的增加而降低.煤尘粒径对其爆炸下限的影响较弱.实验结果与文献中高能量化学药头点火的测试结果进行比较表明,甲烷对煤尘爆炸下限的影响趋势并不随着点火源能量的改变而改变.     

酚醛树脂粉尘爆炸危险性实验研究

针对工业生产中的酚醛树脂粉尘爆炸问题,运用20 L近球形粉尘爆炸特性测试系统,测试了常温常压条件下酚醛树脂粉尘的爆炸下限、最大爆炸压力和最大压力上升速率等爆炸特征参数,分析不同质量浓度与其之间的变化规律,并计算出相应爆炸指数,对爆炸危害等级进行分级。实验结果表明,酚醛树脂粉尘云的爆炸下限质量浓度为10~20 g/m~3;最大爆炸压力、最大压力上升速率和爆炸指数关系曲线变化趋势大致相同,均呈现先升高后降低的现象,并同在200 g/m~3时达到最大值,分别为0.664 MPa,82.5 MPa/s,22.4 MPa·m/s;其粉尘爆炸危害等级为S_(t2)。     

替米考星粉尘爆炸及火焰传播试验研究

为研究制药工业粉尘爆炸事故机制,以典型药物替米考星为对象,分析药物粉尘爆炸和火焰传播特性。主要采用20 L球形爆炸装置、最小点火能(MIE)装置和颗粒图像测速仪(PIV)等设备,试验测试替米考星粉尘的爆炸下限、最大爆炸压力、爆炸指数、MIE和火焰传播速度等指标。结果表明,平均粒径为50μm的替米考星球形颗粒粉尘,其爆炸下限质量浓度为20~30 g/m3,最大爆炸压力为0.89 MPa,最大爆炸指数为25.80 MPa·m/s,MIE为13.20 m J;当粉尘质量浓度为416.67 g/m3时,喷粉初始压力为0.5 MPa,喷粉点火87.5 ms后,竖直管道中火焰传播速度达到最大值34 m/s。     

硬脂酸粉尘爆炸特性试验研究

为研究硬脂酸粉尘的爆炸特性,采用20 L球型爆炸仪对4个粒径范围的硬脂酸粉尘进行粉尘爆炸试验研究。结果表明:一定浓度范围内增大粉尘浓度能够提升硬脂酸粉尘的爆炸能量和燃烧速率。增大粉尘浓度,爆炸猛烈度先增强后减弱;减小粉尘粒径,能增强爆炸猛烈度和敏感度。粒径小于58 μm粉尘的爆炸猛烈度和敏感度最大,浓度500 g/m3时,该粉尘有最大爆炸压力1.12 MPa和最大升压速率142.00 MPa/s。     

水平管道内甲烷-煤尘混合爆炸的试验研究

为研究煤矿甲烷-煤尘混合爆炸的规律,采用水平管道式气体粉尘爆炸装置。试验时,通过延迟爆破系统,将储罐内的煤尘吹入管道内与甲烷气体混合,点火后甲烷爆炸产生的能量作为初始能量引起煤尘的爆炸。通过改变甲烷浓度、煤尘浓度,对甲烷-煤尘混合爆炸的最大爆炸压力和压力上升速率进行了研究。结果表明:最大爆炸压力和压力上升速率随甲烷浓度的增加先增加后减小,随煤尘浓度的增加也先增大后减小。     

Explosibility of fine graphite and tungsten dusts and their mixtures

To evaluate the explosion hazard of ITER-relevant dusts, a standard method of 20-l-sphere was used to measure the explosion indices of fine graphite and tungsten dusts and their mixtures. The effect of dust particle size was studied on the maximum overpressures, maximum rates of pressure rise, and lower explosive concentrations of graphite dusts in the range 4 μm to 45 μm. The explosion indices of 1 μm tungsten dust and its mixtures with 4 μm graphite dust were measured. The explosibility of these dusts and mixtures were evaluated. The dusts tested were ranked as St1 class. Dust particle size was shown to be very important for explosion properties. The finest graphite dust appeared to have the lowest minimum explosion concentration and be able to explode with 2 kJ ignition energy.     

基于20L球形爆炸装置的甲烷煤尘混合爆炸实验

利用实验室自行设计的20L球形爆炸装置,对煤尘及甲烷煤尘混合物的爆炸特性进行了研究。结果表明:无论有无甲烷,煤尘的最大爆炸压力随煤尘浓度增加呈现先升高后降低的变化趋势,并且均在在煤尘浓度为600g/m3时均达到最大值。同时,甲烷的加入明显提高了煤尘最大爆炸压力值,而且随着甲烷浓度的增加,最大爆炸压力增幅先增加后降低,在甲烷5%时增幅最大。煤尘的爆炸持续时间随煤尘浓度增加呈现先降低后升高的特点,甲烷存在时有同样规律,但是有甲烷时爆炸持续时间明显降低,而且随着甲烷含量的增加,煤尘的爆炸持续时间降低幅度不断增加,在甲烷5%以后趋于稳定。实验结果对生产实践有一定的指导作用。     

基于缓和原则的粉尘爆炸风险控制研究

为了将本质安全原理中的缓和原则与粉尘爆炸事故的风险控制联系起来,利用Swiek20 L球形爆炸装置考察了烟煤粉、甘薯粉和镁粉的最大爆炸压力、最大爆压上升速率和爆炸下限等特性,重点考察了点火能量、环境压力以及添加惰化剂等因素的影响。结果表明:降低点火能量能有效缩减粉尘可燃浓度范围,提高粉尘爆炸下限;爆炸危害正相关于环境压力;碳酸钙和碳酸氢钠能有效抑制烟煤尘爆炸,且碳酸钙抑爆效果更好;氯化钾对镁尘爆炸动力学特性的抑制效果更好,而碳酸钙对镁尘爆炸热力学特性的抑制效果更好,且小粒径的惰化剂表现出更好的抑爆炸能力。降低点火能量、控制环境压力和添加惰化剂均可降低粉尘爆炸危害,有助于控制粉尘爆炸风险。     

Experimental mine and laboratory dust explosion research at NIOSH

This paper describes dust explosion research conducted in an experimental mine and in a 20-L laboratory chamber at the Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH). The primary purpose of this research is to improve safety in mining, but the data are also useful to other industries that manufacture, process, or use combustible dusts. Explosion characteristics such as the minimum explosible concentration and the rock dust inerting requirements were measured for various combustible dusts from the mining industries. These dusts included bituminous coals, gilsonite, oil shales, and sulfide ores. The full-scale tests were conducted in the Lake Lynn experimental mine of NIOSH. The mine tests were initiated by a methane–air explosion at the face (closed end) that both entrained and ignited the dust. The laboratory-scale tests were conducted in the 20-L chamber using ignitors of various energies. One purpose of the laboratory and mine comparison is to determine the conditions under which the laboratory tests best simulate the full-scale tests. The results of this research showed relatively good agreement between the laboratory and the large-scale tests in determining explosion limits. Full-scale experiments in the experimental mine were also conducted to evaluate the explosion resistance characteristics of seals that are used to separate non-ventilated, inactive workings from active workings of a mine. Results of these explosion tests show significant increases in explosion overpressure due to added coal dust and indications of pressure piling.     

水平管道内铝粉爆炸特性的试验研究

为研究铝粉在密闭空间内爆炸特性,降低其爆炸造成的损害,利用自行设计的水平管道式可燃气体-粉尘爆炸装置,在室温下对粒度为6～8μm,9～12μm,15～17μm的铝粉在100～800 g/m3浓度范围内的爆炸特性进行试验研究。结果表明:铝粉在浓度为600 g/m3时,最大爆炸压力和最大压力上升速率最大,爆炸时间最小;铝粉浓度较低时,由于氧气充足,随着铝粉浓度增大,最大爆炸压力和最大压力上升速率增大,爆炸时间减小;当铝粉浓度超过600 g/m3,受到氧气浓度限制,最大爆炸压力和最大压力上升速率随浓度增大而减小,爆炸时间增大;相同浓度的铝粉,粒度越小,最大爆炸压力和最大压力上升速率越大,爆炸时间越小。粒度越小的铝粉,爆炸的可能性和危险性越大。     

固体惰性介质对煤粉爆炸压力的影响研究

通过对固体惰性介质在减轻煤粉爆炸作用的实验研究,给出影响固体惰化剂作用效果的主要影响因素。实验分别选用来自加拿大和中国的3种煤粉和石灰石,对每种实验样品的成分、粒度都进行分析。用20L球形容器进行实验,测定煤粉中加入不同含量的石灰石后煤粉爆炸的Pmax和(dp/dt)max值。结果表明,石灰石能够起到减轻煤粉爆炸影响的作用,并且随着煤粉粒度的减小,要达到相同的抑爆效果需要的石灰石的用量将加大。     

The effect of admixed material on the minimum explosible concentration of oil shale

The minimum explosible concentration (MEC) in the air atmosphere at the boundary between an explosion and no explosion in a dust cloud, has been investigated for several particle sizes of oil shale and for mixtures of oil shale and inert powder of different particle size. Limestone, stone dust and coarse particle size of oil shale were used as inert materials. Measurements were made in a standard small vertical tube apparatus. The results obtained indicated that the minimum explosible concentration is dependent on the particle size, i.e., values of MEC decrease with a decrease in the size of the particles. Below 70 μm, values of MEC become almost constant. Admixture of limestone as low as 5% to oil shale is sufficient to reduce the MEC values significantly.     

不同粒径镁铝合金粉尘爆炸与抑爆特性研究

为了研究镁铝合金粉爆炸危险特性,利用20L球形爆炸容器进行测试,结果表明:180目 (80 μm)、 120目(125 μm) 和60目(250 μm)3种粒径下的金属粉尘爆炸下限浓度分别为45 g/m3,55 g/m3和95 g/m3。相同浓度下最大爆炸压力随粒径增大的而减小。以碳化硅和石墨为代表的研究中,60目,120目和180目的镁铝合金粉以10%的浓度梯度加入碳化硅浓度分别至50%,70%和80%,石墨浓度至30%,50%和60%时,镁铝合金粉不会发生爆炸。表明碳化硅及石墨等惰性粉尘都能对粉尘爆炸有抑制作用,其中石墨对镁铝合金粉的抑爆作用明显优于碳化硅。     

Influences of coal dust components on the explosibility of hybrid mixtures of methane and coal dust

In order to study the influences of coal dust components on the explosibility of hybrid mixture of methane and coal dust, four kinds of coal dust with different components were selected in this study. Using the standard 20 L sphere, the maximum explosion pressure, explosion index and lower explosion limits of methane/coal dust mixtures were measured. The results show that the addition of methane to different kinds of coal dust can all clearly increase their maximum explosion pressure and explosion index and decrease their minimum explosion concentration. However, the increase in the maximum explosion pressure and explosion index is more significant for coal dust with lower volatile content, while the decrease in the minimum explosion concentration is more significant for coal dust with higher volatile content. It is concluded that the influence of methane on the explosion severity is more pronounced for coal dust with lower volatile content, but on ignition sensitivity it is more pronounced for coal dust with higher volatile content. Bartknecht model for predicting the lower explosion limits of methane/coal dust mixture has better applicability than Le Chatelier model and Jiang model. Especially, it is more suitable for hybrid mixtures of methane and high volatile coal dust.