粉尘凝并的荷电水雾试验

本文给出了在试验装置上试验不同直径、不同荷质比的荷电水雾对粉尘凝并的效果,阐述了荷电水雾促使粉尘凝并的机理,导出了荷电水雾与XCX型旋风除尘器组合运行时捕集细粉尘的效率。试验表明,经过荷电水雾的微细粉尘,粒径都大于10um,荷电水雾XCX型旋风除尘器相结合时,粒径小于5um的粉尘的捕集效率由10.09％提高到55.31％。     

反向电场电袋过滤PM2.5的试验研究

为高效收集微细颗粒物,提出一种反向电场静电增强袋式除尘器;并研究了过滤风速对反向电场静电增强袋式除尘器除尘效率的影响;试验对比了反向电场静电增强袋式除尘器、预荷电袋式除尘器、普通袋式除尘器的除尘效果,结果表明,反向电场袋式除尘器的除尘性能明显优于普通袋式除尘器和预荷电袋式除尘器.对于处理PM2.5烟雾,当风速为1.5 m/min时,反向电场静电增强袋式除尘器的除尘效率比普通袋式除尘器高10.0％以上;当风速为2.0 m/min时,反向电场静电增强袋式除尘器的除尘效率比普通袋式除尘器高50.0％以上.     

喷射电极静电除尘理论研究

根据当前国内外电除尘器的发展现状和电极结构特点,以改进电除尘器的电极结构和含尘气流的流动方式作为突破口,提出了具有喷射电极结构的静电除尘器.在喷射口周围布置有毛刷钢针芒刺放电极,电晕钢针将在高压电源作用下产生电晕放电.因此,当粉尘随含尘气流从喷口流出时,被电晕荷电.荷电粉尘在气流和电场力的作用下冲向收尘极板,被收尘极板捕集.     

超长夹道预荷电袋滤器气流分布设计与应用

介绍了预荷电袋滤器的基本结构与特点,并与传统袋式除尘器进行了比较,提出了预荷电袋滤器气流组织与气流分布的设计要求和CFD模拟分析方法。通过工程实例介绍了超长夹道大型预荷电袋滤器气流分布CFD模拟分析结果和应用情况,进一步验证了超长夹道预荷电袋滤器气流组织与气流分布设计的有效性和可靠性。     

电袋除尘器中荷电烟尘粒子在滤袋表面的堆积机理

电袋除尘器是在我国排放标准日趋严格的形势下应用而生的一种高效率除尘装置。本文运用静电学理论,结合电除尘和袋除尘技术的除尘机理,从理论和实验两方面,探讨了在电袋除尘器中荷电烟尘粒子在滤袋表面的堆积机理。研究结果表明,与未被荷电的烟尘粒子相比,荷电烟尘粒子由于斥力的作用,在滤袋表面堆积更为疏松,降低了过滤阻力。影响烟尘粒子在滤袋表面堆积的主要因素有斥力、粒径、粒子的电场驱进速度和过滤风速。     

粉尘荷电特性的研究

粉尘荷电是其基本特性之一。研究和分析这种特性,对净化含尘气流,分析除尘器收尘特性和结构设计,都具有重要意义。在荷电场强一定的条件下,粒子的荷电量不是粒子直径的单值函数(即相同粒径的粉尘粒子并不完全荷有相同电量)。而是对某     

微细颗粒物电凝并技术研究的新进展

电凝并技术可有效地提高静电除尘器对微细颗粒物的收集效率.介绍了国内外电凝并理论和技术研究的新进展,并提出一种新型的偶极荷电静电凝并除尘器.     

不同工况下三电极ESP中的扩散荷电效应

利用Gambit构建三电极静电除尘器(ESP)网格模型,在考虑扩散荷电与否的情形下,模拟了颗粒的运动轨迹,计算了不同工作电压、烟气流速下的除尘效率,并加以对比和分析。结果表明,扩散荷电效应对三电极ESP除尘性能的影响较大,不仅增大了颗粒向收尘极板偏转的幅度,而且在低工作电压或高烟气流速时更明显;对于某一种粒径的颗粒,三电极ESP中的扩散荷电效应与提高一定工作电压或降低一定烟气流速相当。     

线-网极配形式的静电场特征分析

静电除尘器的极配和电极形式是除尘器性能的决定因素,它能影响进入除尘器内粉尘的荷电和荷电粉尘的运动。为了解线-网静电极配结构的静电场,根据两种电晕极下的线-网静电极配结构的实验V-I曲线,对包含离子迁移率、除尘器结构几何参数的常数进行了反演,分析了不同电晕极与网状接地极构成的电极对下的电场电流密度特征。结果表明:两种线-网极配结构的V-I特性与经典线-管极配结构的V-I特性具有一致性;在高外加电压下,电晕电流的增加可能带来电晕线的温升,进而使离子迁移率增加;在高低两种外加电压状态下,两种电晕下的电场电流密度值差别是不同的。     

CO_2保护焊烟尘离子荷电技术

目前,国内外对电焊产生的烟尘采用引凤除尘净化方法。一种是全面通风方法,借助室内气流流动将车间内的焊接烟尘带至室外,达到降低焊接烟尘浓度的目的。另一种是局部通风,对电焊部分实行局部封闭通风除尘,以足够高的气流流经工作面,用吸风罩对准电焊点,把电焊时产生的烟尘吸入除尘器净化。但运用这些方法不利于作业环境的布局,还给操作者带来麻烦,最终是不利于工人使用。 电焊烟尘离子荷电就地抑制技术可免除上述除尘技术的缺点,能使在高浓度离子雾里的电焊烟尘被充分饱和荷电,在静电场定向作用下,把刚刚蒸发、燃烧时浮扬起的焊接烟尘就地净…     

Study on the characteristics of gas explosion affected by induction charged water mist in confined space

To investigate the suppression effect of charged water mist on gas explosion, a small charged water mist generator and a gas explosion simulation device were designed based on the principle of electrostatic induction. Experiments for testing characteristics of the gas explosion in a confined space under different charged polarities, charged voltages and mist fluxes were carried out. Experimental results indicated that, compared with the normal water mist, the explosion peak overpressure and the flame propagation speed could be more effectively reduced by the charged water mist. And this suppression effect could be promoted by increasing the charged voltage. To visualize the effect of the charged water mist's polarity on gas explosion, comparative experiments were conducted. The results showed that the explosion peak overpressure, the overpressure rising rate, and the propagation speed of the flame were reduced by 64.7%, 33.0% and 19.4%, respectively, when a +8 kV charged voltage was applied. In situation where a -8 kV charged voltage was applied, 64.1%, 26.5% and 16.0% reductions were achieved for the explosion peak overpressure, the overpressure rising rate, and the flame propagation speed respectively. Comparison of this data leads to the conclusion that the gas explosion could be more efficiently suppressed by the positively charged water mist.     

带电细水雾的灭火实验研究

利用静电感应原理,设计了使细水雾强制带电的感应荷电装置,进行了带电细水雾的灭火实验研究。为研究带电细水雾的灭火效率,在受限空间内,采用小尺度实验方法,通过改变电压的极性和大小、针-环状电极的半径及其距伞罩电极之间的距离,分析对灭火时间和热电偶温度变化的影响。结果表明:带电细水雾比普通细水雾能更迅速地降低火焰温度、熄灭火焰,荷负电的细水雾比荷正电的细水雾具有更好的抑制效果,随着电压的增大、针-环状电极半径及两电极间距的减小,灭火效能提高,熄灭时间减少。     

可吸入性粉尘电凝并效应的实验研究

可吸入性粉尘对环境、人体具有较大的危害,但由于粒径小而难以被除尘器直接捕集。电凝并是通过电场的作用使粉尘粒子荷电而发生凝并,使之有效直径增大从而便于捕集的简单、易行方法。研发采用偶极荷电凝并器并利用重力沉降作用测试可吸入性粉尘电凝并效应的实验装置,在测试段设置沉降板放置若干载玻片作为取样点。采用粉煤灰为实验样品,分别在未荷电、电压18 k V,20 k V 3种状态下进行对比实验研究。实验结果表明,研发的实验装置可以有效测试粉尘在测试段的沉降效果,显微镜直接观察和图像粒度分析处理以及中位径分析表明,荷电凝并后的粉尘粒径明显增大,大粒径粉尘百分比明显提高,平均粒径亦有所增大,且电压越高,效果越明显。     

石灰浆液荷电喷雾烟气脱硫模型与试验

荷电喷雾烟气脱硫技术是在喷雾湿法烟气脱硫基础上引入荷电效应,使之在较低的喷雾量下获得较高的脱硫效率.为了研究其脱硫机理,以实验室小试装置为基础,从气液传质人手对雾滴传质过程进行简化,考虑静电场中雾滴所受的库仑力与极化力,利用双膜理论建立荷电喷雾烟气脱硫过程的数学模型,对脱硫效率进行预测与分析.模型计算及实验结果表明,模...     

一种计算粒子电迁移率的新模型

近几年来,粒子电迁移率引起了更多学者的注意。因为它是表征带电粒子在电场中运动的重要参数之一。在这方面,人们已作了大量的研究工作,提出了一些计算粒子电迁移率的理论和半经验模型。基于前人的研究,本文提出了一种计算粒子电迁移率的新模型,并用前人的实验结果和本研究的实验结果对此模型进行了检验。计算结果和实验数据很吻合。就某种意义上讲,此模型是对以前模型的扩展和改进,它可广泛应用于溶胶的研究和工业应用。     

磁化荷电水雾最佳降尘参数确定实验研究*

为实现对煤尘的有效防控,进一步提高磁化水降尘性能,提出磁化荷电喷雾降尘技术,通过研究液滴在磁化、荷电情况下的受力,揭示磁化荷电喷雾降尘机理;通过自主搭建的动、静态综合除尘实验平台,研究不同磁化强度、荷电电压下溶液表面张力和雾滴粒径的变化规律,进而确定最佳雾化参数。研究结果表明:磁化荷电后的溶液表面张力和雾滴粒径随磁化强度、荷电电压的增大呈现先下降而后上升,最后趋于平稳。荷电电压为9 kV、磁化强度为350 mT时达到最佳效果,此时,与清水相比全尘降尘效率达到92.79%、提高69.63%,呼尘降尘效率达到78.59%、提高94.01%。磁化荷电的溶液表面张力降低,破碎时所做表面功更小,雾化后液滴粒径更小更均匀,与尘粒接触面积增大,可提高捕尘效率,改善矿井环境。     

Characteristics and potential human health hazards of charged aerosols generated by high-voltage power lines

We investigated the characteristics of charged aerosols produced by high-voltage power lines (HVPLs) to explore the effects on respiratory disease incidence among those who handle HVPLs. Charged aerosol currents and charged aerosol concentrations were measured over 24?h at 12 sites. Aerosol current effective levels were 2.7 times higher compared to exposed and control sites. This pattern of relative enhancement at exposed sites was seen consistently in all measurements and the difference was 1.7 higher at exposed sites. Correlation analysis among all important variables revealed strong positive correlations between currents and concentration, currents and magnetic field, humidity and concentration, and humidity and particles of 10?µm or less (PM₁₀), while negative correlations were observed between charged aerosol concentrations and wind velocity and between wind velocity and humidity. Estimated production of charged aerosols from HVPLs found that people who work with HVPLs are highly likely to be exposed to charged aerosols.     

The influence of the charge-to-mass ratio of the charged water mist on a methane explosion

To study the influence of the charge-to-mass ratio of a charged water mist on a methane explosion, the induction charging method was used to induce charge on a normal water mist; a mesh target method was employed to test the charge-to-mass ratio of its droplets. The propagation images, propagation average velocities, and overpressures of a methane explosion suppressed by charged water mist were analysed. The influence of the charge-to-mass ratio of the suppressant water mist on a methane explosion was studied. Results show that the explosion temperature, propagation average velocity, and peak overpressure deceased more obviously with charged water mist than ordinary water mist. With increasing charge-to-mass ratio, the suppression effect of the charged water mist underwent a significant increase. Under experimental conditions, compared with ordinary water mist, when the charge-to-mass ratio was 0.445 mC/kg and the mist flux was 4 L, the minimum flame propagation average velocity was 3.456 m/s, with a drop of 2.37 m/s (40.68%), and the peak overpressure of the methane explosion was 10.892 kPa, with a drop of 10.798 kPa (49.78%). The suppression effect is considered from the changes of the physico-chemical properties of the water mist as affected by the applied charge-to-mass ratio.     

超音速气动液滴荷电雾化及降尘性能试验研究*

为探究煤炭生产过程中呼吸性粉尘难以捕捉且对人体造成伤害的问题,提出超音速水雾荷电降尘技术。基于荷电雾化机理,研究电极环直径、电极间距、电压3因素对超音速气动液滴荷电、雾化效果的影响。利用网状目标法测量雾滴群电流并计算荷质比,采用SPSS软件分析3因素与雾滴荷质比之间的相关性,并用激光粒度仪测量雾滴粒径。最后,采用最优荷电雾化参数进行喷雾降尘试验。研究结果表明:各因素对荷电效果的影响次序为:电压>电极间距>电极环直径;雾滴粒径随电压的升高而减小,随电极间距的增大先增大后减小,随电极环直径的增大先减小后增大;当电压12 kV,电极间距2.5 cm,电极环直径6 cm时,超音速荷电水雾降尘效果最佳,与普通水雾降尘相比,全尘降尘效率提高12.4%,呼尘降尘效率提高49.6%。