声场联合超声波水雾强化过滤式除尘性能的研究

发布时间：2018-01-15 20:41

本文关键词：声场联合超声波水雾强化过滤式除尘性能的研究　出处：《天津大学》2014年硕士论文　论文类型：学位论文

【摘要】：近年来,可吸入颗粒物(PM10)特别是空气动力学直径小于2.5μm的细颗粒物(PM2.5)污染已成为十分突出的大气环境问题,已经引起世界各国的高度重视。火电厂排放的燃煤尘和各种炉窑排放的工业微细粉尘是大气细颗粒物的重要来源,因此,继续发展改进工业除尘技术仍然是大气污染治理的重要方向。其中一种有效的方法是在气溶胶颗粒进入除尘装置前先对其进行预处理,使气溶胶的平均粒径增大,然后在传统除尘器中进行有效脱除。声场和超声波水雾联合作用有利于强化飞灰凝并脱除的效果,是一种有效的预处理方法。本文以某燃煤电厂的飞灰为研究对象,主要研究了燃煤飞灰在中强声场下的凝并特性,燃煤飞灰在声场和超声波水雾联合作用下的凝并脱除特性和以声场和超声波水雾联合作用为预处理下的袋式除尘器滤料的过滤性能。研究结果表明:燃煤飞灰在中等强度声场(110~140 dB)下粒径分布发生变化,小颗粒凝并成为大颗粒,在PM10范围内,较小颗粒的质量百分比明显下降,较大颗粒的质量百分比明显上升。随着声场声压级的逐步提高,凝并效果逐渐增强。声凝并存在最佳的声场频率,最佳频率约为1400Hz左右。飞灰在声场中停留时间在4~7s范围内,随着声场作用时间的增加,颗粒物凝并的效果逐渐增强。声场协同水雾加湿处理可以有效提高飞灰的去除效果。在固定的中强声场下,在适当的雾化加湿范围内(饱和度S=1~2),逐渐提高雾化加湿量以及在固定的雾化加湿量,逐渐提高声强级都有助于提高飞灰的去除率,声场和超声波水雾可以联合使用作为一种预处理的方式。声场与水雾加湿联合作用促进了细颗粒间的凝并沉降,作为预处理方式可以有效降低后续除尘设施的负荷,利于提高后续除尘设施的去除效果。以声场和水雾联合作用作为过滤式除尘的预处理,对粉尘在滤料表面的沉积行为进行了研究并对粉尘颗粒进行了受力分析。粉尘层结构经过该预处理发生了改变,造成孔隙率增加,颗粒沉积后颗粒间不易滑移。清灰实验结果表明,经过声场联合水雾预处理后,清灰周期明显延长,清灰的效率得到提高,排放的粉尘浓度明显降低,提高了滤料的过滤效率。
[Abstract]:In recent years, respirable particulate matter (PM10) especially the aerodynamic fine particles with diameter of less than 2.5 m (PM2.5) atmospheric environment pollution has become a prominent problem, has attracted great attention in the world. The thermal power plant emissions of coal burning furnaces and various emissions of industrial dust is an important source of atmosphere. Fine particles therefore continue to develop improved industrial dust removal technology is still an important direction for air pollution control. One of the effective methods is entered in the dust removing device for aerosol particles before the pretreatment, the average particle size of the aerosol increases, then remove in the traditional dust remover. The combined effect of sound and ultrasonic spray can strengthen the fly ash removal and coagulation effect, is an effective preprocessing method. In this paper, the fly ash from a coal-fired power plant as the research object, mainly studies the coal fly ash in The coagulation characteristics of strong sound field, the filtration performance of coal fly ash in the field and under the combined action of ultrasonic water mist coagulation removal characteristics and to the combined effect of acoustic and ultrasonic spray for baghouse filter pretreatment. The research results show that the fly ash in the middle intensity acoustic field (110~140 dB) particle size distribution changes, small particle coagulation and become large particles in the range of PM10, the mass percentage of smaller particles decreased and the mass percentage of larger particles increased significantly. With the gradual improvement of sound pressure level, coagulation effect gradually. Acoustic coagulation of acoustic frequency exist the best, the best frequency is about 1400Hz. Fly ash in the sound field of residence time in the range of 4~7s, with the increase of the acoustic field time, particle coagulation and the effect of sound field gradually. Collaborative humidification treatment can effectively improve the water removal efficiency. The ash fly The strong field is fixed, the humidifying proper range (saturation S=1~2), gradually improve the humidifying amount and humidifying quantity fixed, gradually improve the sound intensity level will help improve the removal rate of fly ash, acoustic and ultrasonic water mist can be combined as a preprocessing method. The combined effect of water mist field and promote the wetting between fine particles and coagulation sedimentation, as pretreatment method can effectively reduce the subsequent dust removal facilities load, can improve the removal efficiency of dust removal facilities. In the subsequent joint action of sound and mist as a preprocessing filter type dust, the dust deposited on the surface of filter behavior was studied and the dust the particles were stress analysis. After the pretreatment of the dust layer structure changed, resulting in the increase of porosity, particle deposition between particles is not easy to slip after cleaning. The experimental results show that after After the pretreatment of water mist with sound field, the period of ash clearing is prolonged obviously, the efficiency of the dust cleaning is improved, the dust concentration of the discharge is obviously reduced, and the filtration efficiency of the filter material is improved.

【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：X773

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