速生杨木粉尘最小点火能的实验研究

为防止木材加工中木质粉尘燃爆事故的发生,以纤维板生产中常见的原材料速生杨木粉尘作为研究对象,在分析粉尘粒径分布、元素分析、工业分析及形貌特征的基础上,采用1.2 L哈特曼管对3种不同粒径（0~50,＞50~96,＞96~180 μm）速生杨木粉尘进行最小点火能实验,探究点火延迟时间、喷粉压力、质量浓度和粒径分布对速生杨木粉尘最小点火能的影响及变化规律。研究结果表明:在质量浓度为500 g/m3时,分别增加点火延迟时间和喷粉压力,最小点火能都先减小后增大;最佳点火延迟时间和最佳喷粉压力分别为120 ms和120 kPa;粒径对最佳点火延迟时间和最佳喷粉压力无显著影响。在点火延迟和喷粉压力分别为120 ms和120 kPa条件下,最小点火能随质量浓度的增加先减小后增大。粉尘粒径与最小点火能呈正相关性,3种样品的最小点火能分别为1~3,1~3和7~13 mJ,对应的敏感质量浓度分别为500 ,750和1 250 g/m3,属于特别着火敏感性粉尘。     

皮带输煤暗道通风排尘改造方案优化研究

为了解决皮带输煤暗道运输过程中粉尘污染严重及冬季供暖不足问题,对暗道通风供热系统进行了优化改造研究。以中煤平朔安家岭264输煤暗道为例,基于气固两相流理论,利用CFD模拟方法,对暗道内由风速对悬浮粉尘浓度分布的影响规律进行数值仿真。模拟结果显示:当输煤暗道排尘风速由0.25 m/s升至0.35 m/s时,粉尘浓度降为3.2 mg/m3,暗道最大通风阻力为245.94 Pa,最低换热量747.68 kW。基于数值模拟结果,从3种优化方案中选定一压一抽联合式通风除尘方案进行改造,现场实测除尘效果良好,表明所提出的输煤暗道通风除尘方案具有实践指导意义。     

吹吸式通风法在冷轧带钢氧化铁皮除尘中的应用

依据吹吸式通风原理,设计了一种氧化铁皮粉尘污染控制装置,通过对吹气、吸气罩的理论计算及实验分析,提出了具体的设计参数,为冷轧带钢氧化铁皮粉尘的控制提供了依据。     

陶瓷管表面NaHCO3粉体干法脱硫研究

探讨Na HCO3的加热分解特性并将其负载于陶瓷管表面进行了脱硫实验研究,发现Na HCO3在合理的灼烧温度下将在热分解为Na2CO3的过程中形成多孔结构,可在没有液相水存在的情况下成功实现SO2去除,灼烧温度过高则发生颗粒烧结从而降低脱硫效果;进口气流SO2浓度150 ppm的情况下,陶瓷管表面厚度仅仅50μm的Na HCO3粉体可以在20~40 min内将出口气流中的SO2限制在17.5 ppm(50 mg/m^3)的超净排放限值以下。Na HCO3作为干法脱硫剂可在不明显提高烟气湿度和降低其温度的条件下成功实现脱硫,结合陶瓷过滤管的除尘作用,有望实现烟气的深度除尘和脱硫操作的一体化。     

青海高原一次沙尘重污染天气成因分析

利用常规观测的卫星云图资料、地面资料、探空资料、地面污染物监测数据,结合拉格朗日粒子扩散模型(LPDM)污染源溯源方法,对2018年2月青海高原一次沙尘重污染天气的主要成因以及沙尘传输特征进行了分析。结果表明:此次重污染天气受高空低槽东移影响,在300~700 hPa形成了强烈的辐散下沉,槽后的高空急流随之东移。在其东移过程中,受高空急流动量下传及偏北气流中的冷空气共同作用,青海东部出现了大风沙尘天气。边界层中逆温层的存在是此次污染天气持续的重要原因之一,加之未出现明显降水,不利于大气污染物的扩散。通过运用LPDM对此次污染天气的运动轨迹进行分析来看,气团影响的模拟高度层距离地面100 m,气团层趋势一致。研究区地处青藏高原,海拔较高,0~100 m高度的气团足迹可以反映出PM 10污染气团的输送路径。同时,0~100 m是主要的人为源排放空间,也是对人类活动影响较大的区域。气团足迹与PM 10浓度的变化趋势一致,即青海东部沙尘污染主要是由河西走廊沙尘倒灌进入青海东部导致,这与天气学分析结果一致。     

Using soybean isoflavone to prevent hydrogen production reaction of aluminium dust and water in wet dust removal systems

Using a dry dust removal system used for aluminium dust collection presents a dust explosion risk, whereas a wet dust removal system presents a risk of hydrogen fire and explosion. Neither system can attain a sufficient level of safety for use at aluminium processing sites. In this paper, soybean isoflavone, a non-toxic and environmentally sustainable flavonoid, was investigated to inhibit hydrogen production from aluminium dust and water. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR) were used to characterize aluminium particles before and after the reaction. Soybean isoflavone was found to inhibit hydrogen production from aluminium dust and water. At a soybean isoflavone solution concentration of 2.1 g L⁻¹, a dense protective film resulting from chemical adsorption on the surfaces of the aluminium particles isolated the aluminium particles from water molecules. This film blocked the reaction pathway between the aluminium particles and water to suppress hydrogen generation. This fundamental study addresses the problems of hydrogen fires and explosions in wet dust removal systems for aluminium dust collection and provides a novel, safe and effective method for aluminium dust removal.     

Effect of flame propagation regime on pressure evolution of nano and micron PMMA dust explosions

Experiments using an open space dust explosion apparatus and a standard 20 L explosion apparatus on nano and micron polymethyl methacrylate dust explosions were conducted to reveal the differences in flame and pressure evolutions. Then the effect of combustion and flame propagation regimes on the explosion overpressure characteristics was discussed. The results showed that the flame propagation behavior, flame temperature distribution and ion current distribution all demonstrated the different flame structures for nano and micron dust explosions. The combustion and flame propagation of 100 nm and 30 μm PMMA dust clouds were mainly controlled by the heat transfer efficiency between the particles and external heat sources. Compared with the cluster diffusion dominant combustion of 30 μm dust flame, the premixed-gas dominant combustion of 100 nm dust flame determined a quicker pyrolysis and combustion reaction rate, a faster flame propagation velocity, a stronger combustion reaction intensity, a quicker heat release rate and a higher amount of released reaction heat, which resulted in an earlier pressure rise, a larger maximum overpressure and a higher explosion hazard class. The complex combustion and propagation regime of agglomerated particles strongly influenced the nano flame propagation and explosion pressure evolution characteristics, and limited the maximum overpressure.     

转炉二次除尘系统问题诊断及运行优化

针对某企业150 t转炉二次除尘系统烟气捕集效果不佳、布袋除尘器压差大、运行能耗高等问题进行了系统诊断,利用排查系统管网、实测压力和流量、分析风机特性等手段,找出了问题原因并提出改进措施。通过实施改进措施,优化了150 t转炉二次除尘系统的运行方式,确保二次除尘效果并实现节能、经济运行。     

我国作业场所粉尘职业危害现状与对策分析

为进一步解决我国作业场所粉尘职业危害问题,保障劳动者的职业健康,践行《健康中国2030》国家战略,本文采用资料分析、问卷调查、政策研究、专家咨询等方法,分析与梳理了我国作业场所的粉尘职业危害现状、尘肺病发病的主要特征、粉尘防控存在的突出问题。基于分析与研究,提出加大防尘技术支撑机构建设力度、加强粉尘防治重点科技攻关、提高粉尘防治信息化水平以及职业健康人才队伍建设等粉尘危害防控对策与措施。