麻石泡沫脱硫除尘处理技术的工业应用

简介麻石泡沫脱硫除尘处理技术的基本原理、工艺系统主要特性。侧重介绍了麻石泡沫脱硫除尘处理技术应用在35t/h燃煤锅炉上的投资与效益分析。     

负载TiO2的泡沫镍网光催化降解甲醛的膜厚优化

采用负载TiO2的泡沫镍网光催化降解甲醛,考虑内部和外部质量传递,建立了可预测优化催化剂膜厚的数学模型.分析了TiO2膜厚对光催化降解甲醛的影响,并在模型基础上分析了催化剂层内光的衰减系数和污染物的有效扩散系数对最优催化剂膜厚的影响.结果表明,随着催化剂膜厚的增加,甲醛的降解先增加而后趋于平缓;最优催化剂膜厚受UV光衰减系数的影响较大,受污染物的有效扩散系数的影响较小;由于TiO2催化剂对254nmUV光的强烈吸收,优化的催化剂膜厚只有80nm左右.该模型对实验数据拟合较好.     

吸波结构聚氨酯泡沫基体材料耐老化性能评估试验设计

目的针对吸波结构的基体材料——一种软质聚氨酯泡沫耐老化性能的考核,设计一种环境适应性试验,确定施加的环境应力和产品老化性能的表征参数。方法通过吸波结构的聚氨酯泡沫材料的特征性能参数分析,根据产品应用要求和预试验结果,确定合适的老化性能的主要表征指标,通过多应力水平试验和方差分析,确定采用的主要加速老化环境应力。结果通过预试验与分析认为,吸波结构用聚氨酯泡沫材料耐老化性能可采用断裂伸长率来作表征,由于防水覆膜能很好地阻隔水汽对聚氨酯材料的影响,采用单温度应力便可以来考核其老化性能。结论针对具有防水覆膜的吸波结构用聚氨酯泡沫材料,采用单温度应力作用下的断裂伸长率变化可以对其耐老化性能进行有效评估。     

微米级空心玻璃微珠三相泡沫稳定性研究

基于水成膜泡沫灭火剂(AFFF),用微米级空心微珠颗粒作为泡沫稳定剂,制成三相泡沫,并研究了泡沫组成因素对发泡能力和泡沫稳定性的影响。采用控制变量法,研究了颗粒浓度、颗粒粒径、AFFF原液浓度对发泡倍数和析液时间的影响。颗粒加入对发泡能力有抑制作用;因为颗粒存在影响,三相泡沫的发泡能力随AFFF原液浓度增大而减小;40μm粒径颗粒的抑制作用相对20μm和60μm颗粒最小。颗粒浓度和AFFF原液浓度增加,能够提升三相泡沫稳定性,且泡沫析液时间随颗粒浓度增加呈指数规律变化。当AFFF原液浓度为3.0%、颗粒浓度为9%左右时,三相泡沫稳定时间约为两相泡沫的3倍,该配方三相泡沫有较好的稳定性。     

压缩空气泡沫灭火系统扑救浮顶储罐密封圈火灾的应用研究

分析了密封圈火灾过程及特点,建立了压缩空气泡沫灭火试验装置,参照10×10~4m~3浮顶储罐建立了20 m长的密封圈试验装置,以汽油为介质开展了多次泡沫灭火试验。试验结果表明:该压缩空气泡沫灭火试验装置可在30 s内完成灭火,泡沫混合液供给强度约14~19 L/(min·m~2),具有在大型浮顶储罐上应用的可能性。针对单台10×10~4m~3浮顶储罐浮盘密封圈灭火提出了工程应用方案,该储罐共需泡沫液量1200 L,分为4套压缩空气泡沫灭火装置均匀分布在浮盘边缘,浮盘密封圈火灾报警系统与该泡沫灭火装置联锁启动自动灭火,各套灭火装置的持续喷射时间约1 min。     

Procedure for the determination of 2,4‐D and dicamba in inhalation,dermal, hand‐wash,and urine samples from spray applicators

Abstract

Analytical procedures for the simultaneous determination of residues of 2,4‐D and dicamba from polyurethane foam plug air samplers, ethylene glycol impregnated glass‐fiber filter paper dermal samplers, 1% sodium bicarbonate hand wash solution, and urine are presented. Residues were derivatized with diazomethane and quantitated using electron capture gas chromatography. Recoveries were greater than 80% at the limit of detection in all substrates. The limits of detection for both herbicides were 0.1 μg/foam plug and 0.5 μg/filter paper, and in the urine, 1.7 μg/100 mL and 5.0 μg/100 mL for dicamba and 2,4‐D, respectively.     

Development of metal organic framework-199 immobilized zeolite foam for adsorption of common indoor VOCs

Reticulated foam shaped adsorbents are more efficient for the removal of volatile organic compounds (VOCs), particularly from low VOC-concentration indoor air streams. In this study composite structure of zeolite and metal organic frameworks (MOFs), referred as ZMF, has been fabricated by immobilization of fine MOF-199 powder on foam shaped Zeolite Socony Mobil-5 (ZSM-5) Zeolitic structure, referred as ZF. The ZMF possess a uniform and well-dispersed coating of MOF-199 on the porous framework of ZF. It shows higher surface area, pore volume, and VOCs adsorption capacity, as compared to ZF-structure. Post-fabrication changes in selective adsorption properties of ZMF were studied with three common indoor VOCs (benzene, n-hexane, and cyclohexane), using gravimetric adsorption technique. The adsorption capacity of ZMF with different VOCs follow the order of benzene > n-hexane > cyclohexane. In comparison with MOF-199 and ZF, the composite structure ZMF shows improvement in selectivity for benzene from other two VOCs. Further, improvement in efficiency and stability of prepared ZMF was found to be associated with its high MOF loading capacity and unique morphological and structural properties. The developed composite structure with improved VOCs removal and recyclability could be a promising material for small to limited scale air pollution treatment units.     

胶态泡沫在饱和介质迁移特性及对PCE冲洗效果

利用表面活性剂胶态微泡沫冲洗技术来提高四氯乙烯（PCE）在地下水的溶解性和流动性,提高污染物迁移通量,强化去除效果.主要工艺参数和影响因素对泡沫稳定性的影响,结果表明4000r/min的搅拌转数即可产生稳定的胶态微泡沫,泡沫稳定性随表面活性剂浓度增大有小幅度提高,PCE对泡沫稳定性有不利影响;胶态微泡沫在含水层的迁移规律表明,泡沫前端迁移时不断破裂并气液分离,形成气体在上部,液体在下部,后续泡沫稳定向前推流的迁移模式,泡沫在含水层中受到地下水的静水压力,与在土壤迁移相比其体系压力更大,泡沫破裂更严重、迁移速率更慢;和液体冲洗相比,泡沫冲洗对PCE增溶增流效果明显,介质粒径为0.1~0.25mm、0.25~0.5mm和0.5~1mm时,PCE去除率分别达到83.7%、90.8%和98.2%,介质粒径越大,去除效果越明显.     

Research on the influence of foaming gas in compressed air/nitrogen foam on extinguishing the n-heptane tank fire

Tank fires threaten the lives of people and pollute the environment for their intense radiant heat, rapid fire spread and explosion hazard. Compressed air/nitrogen foam (CAF/CNF), a cleaner fire extinguishing technique used for the tank fire suppression because halogen-based agents were prohibited for environmental reasons. In this work, the influence of foaming gas in CAF/CNF on extinguishing the n-heptane tank fire was firstly investigated. Firstly, it was found that CNF spreads faster with rapid increase in foam thickness, mainly due to its better stability and less evaporation. Secondly, after foam was discharged, there existed a short increase of the combustion intensity, associated with three monotonous regions and two time delays in the whole extinguishing time. The two time delays were caused by Rayleigh–Taylor instability and flame sheet shift, respectively, and the shift distance was larger for CNF. Finally, the influential factors contributing to flame extinction were exhibited to be mainly related to the decrease in liquid burning rate and gas-phase Damkohler number. Among these factors, foam spreading rate and thickness dominated due to coupled chemical and physical extinguishing effects. Resulted from some competitive effects, CNF was slightly more efficient at extinguishing tank fires than CAF.     

Improved research-scale foam generator design and performance characterization

The release of a cryogenic, flammable liquid, such as LNG, poses a threat to individuals in the area of the release as well as responders who attempt to limit the damage of the release. The most common mitigation technique is high-expansion foam which can be used to blanket the liquid, reducing the accumulation of flammable vapor above the pool through a number of different mechanisms. Despite the effectiveness of high-expansion foam blanketing, there are many aspects of the interaction between foam and LNG that are unknown. A lab-scale high-expansion foam generator has been developed to allow the study of those interactions. Additionally, the novel foam generator design addresses many of the drawbacks of industrial-scale foam generators and allows researchers better control of the foam, while producing foam at rates that are conducive to lab applications. Foam was produced using the generator and expansion ratio and foam stability were measured to determine the quality. The generator was able to produce foam with expansion ratio between 298 and 892 that collapsed at an average rate of 0.4 cm per minute. This quality of the foam is comparable to industrial-scale foam generators and the foam production rate is between 1.2 and 2.2 m³/min, which fits lab-scale needs. The foam generator can also be used with other types of non-firefighting foam, such as decontamination foam for chemical, biological, or nuclear decontamination.