超声波雾化技术捕集微细颗粒物性能的研究

发布时间：2018-05-28 05:04

本文选题：超声波水雾 + 微细颗粒物　；参考：《北京化工大学》2015年硕士论文

【摘要】：近年来,微细颗粒物成为我国城市环境空气首要污染物,对自然环境和身体健康造成极大的威胁,国内外更加严格的控制微细颗粒物的排放。常用的除尘技术虽然总除尘效率较高,但对粒径较小的微细颗粒物的捕集效率较低。通常利用预团聚技术增大微细颗粒物的粒径,再使用常用除尘设备对其进行捕集,降低微细颗粒物的排放浓度。超声波雾化除尘技术是基于蒸汽相变团聚原理改进的新除尘技术之一,其特点就是高捕集效率,能够有效地去微细颗粒物,有效促进与微细颗粒物的团聚。在捕尘过程中用水量极少,避免了普通雾化捕尘过程耗水量过大的弊病。本研究尝试将超声波雾化技术与过滤除尘技术相结合,在常用除尘装置前添加超声波水雾对微细颗粒物进行预团聚,使微细颗粒物的粒径增大到常用除尘装置所能脱除的范围,再使用纤维过滤除尘设备对微细颗粒物进行捕集。实验研究方面,设计和搭建超声波雾化除尘装置,采用5000目碳酸钙颗粒模拟粉尘,以PP纤维作为纤维滤料,由空气压缩机和超声波雾化喷嘴提供超声波水雾。研究不同操作条件(加雾方式、过滤速度、滤料厚度、滤料填充率、粉尘浓度、雾粉比等)对除尘效率及过程压降的影响及变化规律。实验结果表明：采用网前对喷的加雾方式除尘效率较高,且过程压降变化较小；除尘效率随风速增加而降低,过程压降随着风速的增加而增大；除尘效率和过程压降都随着滤料厚度增加而增大,但当除尘效率较高时,增加滤料厚度对除尘效率影响不大,而过程压降会随之增大；除尘效率随滤料填充率增大而提高,滤料填充率达到一定程度后,除尘效率增加缓慢,过程压降会随着滤料填充率增大而增大；除尘效率和过程压降随着粉尘浓度增加而增加；除尘效率随着雾粉比的增加而增加,且增加速率逐渐降低,过程压降随着雾粉比的增加呈现先增加后降低再增加的趋势；在雾化溶液中添加适量表面活性剂有利于提高除尘效率,降低过程压降；基于量纲分析,建立除尘效率的数学模型,并用拟合工具得到最终除尘效率与其影响因素的函数关系式。本文在过滤除尘装置前添加超声波水雾以提高装置的除尘效率,降低过程压降,并在雾化溶液中添加适量的表面活性剂,使除尘效率得到提高。基于量纲分析法建立数学模型,利于对除尘系统进行最优设计。
[Abstract]:In recent years, fine particulate matter has become the primary pollutant of urban air in China, which poses a great threat to the natural environment and health, and the emission of fine particulate matter is more strictly controlled at home and abroad. Although the total dust removal efficiency of the common dust removal technology is high, the capture efficiency of fine particles with smaller particle size is lower. Preagglomeration technology is usually used to increase the particle size of fine particles, and then collect them with common dust removal equipment to reduce the emission concentration of fine particles. Ultrasonic atomization is one of the new dedusting techniques based on the principle of steam phase change agglomeration, which is characterized by high capture efficiency, effective removal of fine particles and effective agglomeration with fine particles. In the process of dust capture, the water consumption is very small, which avoids the problem of excessive water consumption in the ordinary atomization process. This study attempts to combine ultrasonic atomization technology with filtration and dust removal technology, adding ultrasonic water mist to pre-agglomeration of fine particles in front of common dust removal devices, so that the particle size of fine particles can be increased to the range that can be removed by common dust removal devices. The fine particles were collected with fiber filter and dust removal equipment. In the experimental research, the ultrasonic atomization dust removal device was designed and built. 5000 mesh calcium carbonate particles were used to simulate the dust, and PP fiber was used as the fiber filter material. The ultrasonic water mist was provided by air compressor and ultrasonic atomization nozzle. The effects of different operating conditions (fogging mode, filtration speed, filter media thickness, filter media filling ratio, dust concentration, fog-powder ratio, etc.) on the dust removal efficiency and pressure drop in the process were studied. The experimental results show that the dust removal efficiency of spray is higher and the change of process pressure drop is small, the dust removal efficiency decreases with the increase of wind speed, and the process pressure drop increases with the increase of wind speed. Both the dust removal efficiency and the process pressure drop increase with the increase of the filter material thickness. However, when the dust removal efficiency is high, the increase of the filter material thickness has little effect on the dust removal efficiency, but the process pressure drop will increase, and the dust removal efficiency increases with the increase of the filter material filling rate. When the filter media filling ratio reaches a certain degree, the dust removal efficiency increases slowly, and the process pressure drop increases with the filter media filling rate, the dust removal efficiency and the process pressure drop increase with the increase of dust concentration, and the dust removal efficiency increases with the increase of the fog-powder ratio. And the increase rate gradually decreased, the process pressure drop increased first and then decreased with the increase of fog-powder ratio. Adding appropriate surfactant in atomization solution was beneficial to increase the dust removal efficiency and reduce the process pressure drop. The mathematical model of dust removal efficiency is established, and the functional relationship between the final dust removal efficiency and its influencing factors is obtained by fitting tools. In this paper, ultrasonic water mist is added to filter and dedusting device to improve the dust removal efficiency and reduce the pressure drop in the process. The dust removal efficiency is improved by adding a proper amount of surfactant in the atomization solution. A mathematical model based on dimensional analysis method is established, which is beneficial to the optimal design of dust removal system.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X701.2

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