关于改进麻石水膜除尘脱硫技术的探讨

锅炉除尘技术很多,近年来麻石水膜式除尘器得到了广泛的应用,同时麻石水膜除尘器技术也不断得到进步,从技术方案创新和工艺改进方面都取得了很大的成绩,值得我们去总结和探讨。     

对选矿厂生产性粉尘的治理措施

本文介绍了某钢选矿厂破碎车间治理粉尘污染所采用的密闭、加湿机械除尘、改造除尘器、高压静电除尘及湿式除尘等方法收到的效果,     

Size distribution and di use pollution impacts of PAHs in street dust in urban streams in the Yangtze River Delta

Particles of dust washed o streets by stormwater are an important pathway of polyaromatic hydrocarbons (PAHs) into urban streams. This article presented a comprehensive assessment of the size distribution of PAHs in street dust particles, the potential risks of the particles in urban streams, and the sources and sinks of PAHs in the stream network. This assessment was based on measurements of 16 PAHs from the USEPA priority list in street dust particles and river sediments in Xincheng, China. The content of total PAHs ranged from 1629 to 8986 g/kg in street dust particles, where smaller particles have a higher concentrations. Approximately 55% of the total PAHs were associated with particles less than 250 m which accounted for 40% of the total mass of street dust. The PAH quantities increased from 2.41 to 46.86 g/m2 in the sequence of new residential, rising through main roads, old town residential, commercial and industrial areas. The sediments in stream reaches in town were found to be sinks for street dust particle PAHs. The research findings suggested that particle size, land use and the hydrological conditions in the stream network were the factors which most influenced the total loads of PAH in the receiving water bodies.     

复合型水雾抑尘剂作用机理与优选方法研究*

为有效提高水雾综合除尘性能,基于水雾捕尘过程及抑尘作用机理,从复合抑尘剂润湿、吸湿、黏结作用组分出发,讨论不同性质粉尘与抑尘剂各组分间匹配协同关系,进而研究复合型水雾抑尘剂优选方法。结果表明:湿润组分优选疏水端含有碳碳双键、醚基或链间存在氢键的表面活性剂;通过改变疏水基链长、不饱和度和支链数等方法,使湿润组分亲水、亲油性与粉尘相匹配。吸湿组分优选体心立方晶胞结构、溶解度相对较小的无机盐或混合配方无机盐,或者含极性强、能形成氢键的基团且空间结构复杂的有机吸湿剂。黏结组分优选溶液黏度高、交联网状、结构复杂的高分子聚合物。在上述组分优选的基础上,通过抑尘剂复配性能实验合理确定各组分的最优配比。     

Improving the safety of distracted pedestrians with in-ground flashing lights. A railway crossing field study

Introduction: Current signage at intersections is designed for attentive pedestrians who are looking ahead. Such signage may not be sufficient when distracted by smartphones. Illuminated in-ground LED lights at crossings are an innovative solution to alert distracted pedestrians. Method: We conducted a field study at a railway crossing equipped with in-ground lights to assess whether distracted pedestrians (N = 34, Mean age 33.6 ± 8.6 years) could detect these lights and how this impacted on their visual scanning and crossing behaviour. This involved a 2 × 3 repeated measures design exploring the impact of the presence (treatment) or absence (control) of in-ground lights (treatment) at a crossing, and a distractor task presented through a mobile device (none, visual, and audio) on eye movements recorded using an eye tracker, and verbal reporting of when participants detected the lights. Results: Participants engaged in the distraction tasks as evidenced by their accuracy and reaction times in all conditions. With both the audio and visual distraction tasks, participants looked at the in-ground LEDs and detected their activation as accurately as when not distracted (95%). While most participants detected the lights at their activation, visual distraction resulted in 10% of the detections occurring as participants entered the rail corridor, suggesting effectiveness in gaining pedestrians’ attention. Further, participants were significantly less likely to check for trains when visually distracted (70%), a 10% reduction compared to the no or audio distractor conditions (80% and 78% respectively). The introduction of the in-ground lights resulted in appropriate scanning of the rail tracks (77% and 78% for the visual and auditory distractor tasks respectively) similar to that of non-distracted participants for the crossing without lights (80%). Conclusions: Our findings indicate that illuminated in-ground lights could be useful in attracting the attention of distracted pedestrians at railway level crossings, and possibly at other road intersections. Practical Applications: Illuminated in-ground lights can be installed at rail and road intersections with known pedestrian distraction as a countermeasure. Further research is necessary to understand their long-term effects.     

基于半定量的FRAM道路危险品运输事故分析方法研究*

为弥补事故分析法在道路危险品运输事故致因研究方面的缺失,解决传统事故分析方法分析结果不全面、防控措施不具体且针对性较差的问题,引入半定量功能共振事故模型（FRAM）,通过定量化功能上下游耦合变异性,阐述事故发生机理同时,找到系统关键功能和关键链路,制定防控措施重点监控。结果表明:基于半定量的FRAM道路危险品运输事故分析方法能够更快、更准确地找出事故发生的关键功能和关键链路,制定针对性防控措施,有效提高道路危险品运输系统安全性。研究结果可为道路事故分析提供参考。     

湿式除尘器氢气爆炸事故控制研究*

为降低铝合金湿式除尘系统发生氢气爆炸事故的风险,提出1种氢气抑制的方法用来降低铝合金湿式除尘系统发生氢气爆炸事故的可能性。选取柠檬酸钠作为抑制剂开展抑氢实验研究,得到不同浓度的柠檬酸钠溶液随时间变化的抑氢曲线。当柠檬酸钠溶液浓度为0.4~4 g/L时,能有效抑制铝合金粉尘与水的反应。通过扫描电子显微镜(scanning electron microscope,SEM)和能量色散谱（energy dispersive spectroscopy,EDS)分析对铝合金粉与柠檬酸钠溶液反应后的产物进行表征。最后,对本文提出的抑氢方法的经济性进行分析,明确该方法在节约安全投入方面具有非常明显的优势。抑氢本质化安全设计方法为控制铝合金湿式除尘系统氢气爆炸事故提供了1种新的思路,同时也可被控制核反应堆氢气爆炸事故所借鉴。     

基于量子化学分析表面活性剂对不同煤种润湿机理的影响*

为研究不同类型表面活性剂对煤润湿性的调控机理,首先将所选煤样的润湿性与煤样成分进行关联分析,然后采用透过高度法实验及量子化学计算相结合的方法研究表面活性剂对煤样润湿性的影响效果及机理。结果表明:煤的润湿性与煤中固有水分、灰分呈正相关关系,与煤中固定碳呈负相关关系;所选取的4种表面活性剂的加入会降低褐煤的亲水性,而对长焰煤、焦煤和无烟煤亲水性有提升作用,并且十二烷基硫酸钠对于这3种煤样亲水性的提升作用最为明显;表面活性剂分子、水分子及煤分子的表面静电势分布共同决定了表面活性剂对煤浸润性的影响。     

基于FLUENT的炼钢电炉车间粉尘控制措施优化*

为降低炼钢电炉车间粉尘对作业人员的危害,通过对某钢铁厂电炉车间实际情况为研究背景,利用现场调研与数值模拟对炼钢电炉车间的粉尘空间分布以及粒子运动规律进行分析。在采用FLUENT粒子流场综合计算的理论基础上,利用DPM颗粒运动轨道中的离散运动模型,加载粒子相,并综合计算两相流,最终得到粒子的运动规律。通过分析逃逸扩散粉尘在不同空间分布中的情况以及扩散粉尘颗粒物逃逸率的情况,综合分析对车间环境造成的影响。结果表明:粉尘粒径越小,对气流的跟随性越好,排风口对粉尘的捕集效果越差;集气罩的安装位置距离污染源越近捕集效果越好;集气罩的尺寸越大对粉尘的捕集效果越好。     

北京市交通扬尘对大气环境质量的影响

利用中尺度气象模式ARPS与空气质量模式Models-3/CMAQ的耦合模式,模拟2002年4个季节代表月份(1月、4月、8月和10月)北京市PM10浓度的时空分布.与监测数据对比分析表明,该耦合模式有很好的可靠性.设计了2种污染源情景方案,分析了北京市2002年4个季节代表月份交通扬尘对市区大气PM10的影响.结果表明,在4个代表月中,交通扬尘对北京市PM10的逐时贡献率波动较大,最高可达33%,最低为3%;交通扬尘对北京市大气PM10影响显著,4个月平均贡献率分别为16.73%、12.92%、18.56%和18.17%,平均贡献浓度分别为27.61 μg/m3、32.80 μg/m3、25.20 μg/m3和24.40 μg/m3.此外,依据模拟结果,结合交通扬尘污染特征与治理现状,提出了北京市交通扬尘的初步治理方案.