泛比电阻电除尘器伏安特性的理论及实验研究

粉尘比电阻是影响电除尘器收尘效率的一个重要因素,为扩展电除尘器对粉尘比电阻的适应范围,提高对泛比电阻粉尘的收尘效率,提出一种具有辅助电极和交错平板收尘极的新型电除尘器,并对其伏安特性进行了研究。结果表明,泛比电阻电除尘器的收尘场强比普通的线-板式电除尘器高,而且更均匀,辅助电极对电晕电流具有明显的抑制作用。     

放电极雾化介质阻挡放电低温等离子体对染料溶液的脱色研究

采用放电极雾化介质阻挡放电装置,以靛蓝二磺酸钠染料溶液为接地雾化水电极,将有玻璃介质保护的平板电极通入60 Hz交流电,在常压空气中放电形成低温等离子体,对染料溶液进行脱色试验. 结果表明:随着电压的升高和空气间隙的减小,放电电流增大;在相同处理时间内,随着电压的增大和空气间隙的减小,脱色率逐渐增大. 当空气间隙为30 mm,电压为30 kV,处理时间为18 min时,染料溶液的脱色率可达95%以上. 空气间隙和电压的不同,脱色率每提高1%的能量消耗量不同,空气间隙为30 mm时脱色率每提高1%的最低能量消耗量为34.81 J,电压为25 kV时脱色率每提高1%最低能量消耗量为49.56 J. 空气间隙为30 mm,电压为25 kV,可实现在较低的能量消耗下达到较高的脱色率.      

Characteristics and hazards of electrostatic discharges in air

In the assessment of electrostatic hazards in the process industries, a great deal of emphasis has been placed on the determination of energies in spark discharges. There are, however, other electrostatic discharge phenomena where this approach has severe limitations. The purpose of this paper is to describe the state-of-the-art with respect to electrostatic discharges in gases (air). An in depth review of the literature has been made, and the various types of discharges are tabulated and discussed.     

改性超细粉体灭火性能模拟实验研究

针对新一代超细高效粉体灭火剂的要求,构建了一套小型固定式粉体灭火装置,对3种粉体的灭火性能进行对比研究,通过扫描电子显微镜(SEM)观察粉体颗粒的粒径分布和表面形态,研究了粒径等因素影响粉体灭火性能的规律,指出了改性前后粉体灭火时间不同的原因.实验结果表明,与普通干粉相比,经改性细化的粉体的灭火时间缩短了1/2,灭火性能显著提高.     

Suppression effects of powder suppressants on the explosions of oxyhydrogen gas

Suppression tests of oxyhydrogen gas explosions were performed in an explosion tube with five types of dry powder used as the suppressants. The experimental results showed that the powder with large dust cloud density and small radius has better suppression effect, which agrees well with previous correlative results. Moreover, our results also showed that particles with chemical activity and light material density, their suppression effect are more prominent than that of the inert particles with heavy density. To discover the detailed suppression process of dust powder, governing equations were developed based on the homogeneous reactive two-phase flow. The TVD scheme and the Lax–Wendroff–Rubin scheme were adopted to solve the reactive gas phase and particle phase, respectively. The time splitting technique was employed to handle the stiffness of the coupled equations. Our calculated results showed that the dust cloud has the suppression effect on the explosion of oxyhydrogen gas, and with the increase of dust cloud density or the decrease of particle diameter, its suppression effect become more evident, which is in good agreement with our experimental results, in addition, the numerical results showed that with the same particle diameter, the suppression performance is enhanced with the reduction in particle material density.     

包钢高炉出铁场烟尘的治理

包头钢铁集团公司共有六座高炉,这里出铁场高浓度的烟尘对厂区大气环境造成严重污染,直接危害职工的身体健康,同时影响周边的环境。六座高炉全部实现干法除尘,成为国内大型钢铁企业中首家实现高炉全干法除尘的企业,对出铁场烟尘进行净化处理,净化后的气体可直接排入大气,改善了钢铁生产污染严重的现状。出铁场烟尘控制的关键处为出铁口、撇渣器、摆动流嘴三处。抓住了出铁场烟尘控制的关键环节,就加强了对出铁口烟尘的控制。     

Sequestration of toxic Pb（II） ions by chemically treated rubber （Hevea brasiliensis ） leaf powder

Rubber leaf powder (an agricultural waste) was treated with potassium permanganate followed by sodium carbonate and its performance in the removal of Pb(II) ions from aqueous solution was evaluated. The interactions between Pb(II) ions and functional groups on the adsorbent surface were confirmed by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) coupled with X-ray energy dispersive spectroscopy (EDX). The effects of several important parameters which can affect adsorption capacity such as pH, adsorbent dosage, initial lead concentration and contact time were studied. The optimum pH range for lead adsorption was 4–5. Even at very low adsorbent dosage of 0.02 g, almost 100% of Pb(II) ions (23 mg/L) could be removed. The adsorption capacity was also dependent on lead concentration and contact time, and relatively a short period of time (60–90 min) was required to reach equilibrium. The equilibrium data were analyzed with Langmuir, Freundlich and Dubinin-Radushkevich isotherms. Based on Langmuir model, the maximum adsorption capacity of lead was 95.3 mg/g. Three kinetic models including pseudo first-order, pseudo second-order and Boyd were used to analyze the lead adsorption process, and the results showed that the pseudo second-order fitted well with correlation coefficients greater than 0.99.     

电除尘器中粒子沉降特性研究

为更准确地描述粉尘粒子在电除尘器电场中的浓度分布,文章在现有电除尘器粉尘粒子沉降模型的基础上,通过引入影响因子的概念对改进的三维数学模型及其除尘效率估算方法进行了分析讨论,得到了不同精度下的除尘效率估算式和相应参数的估算方法。针对细粉尘,结合实验数据,得到预测其除尘效率时可以忽略竖直方向浓度变化,公式η=1-(e-1)e-al/fvω可以在无特殊边界条件下进行效率估算。这些为电除尘器的设计和运行提供了一定的参考价值。     

烟道中同极性荷电粉尘的凝并研究

针对目前电除尘器对微小颗粒粉尘捕集效率低、本体体积庞大的问题,突破传统预荷电装置的应用模式,将预荷电装置安装于电除尘器模拟烟道中,进行了高压电场荷电凝并研究,考察了凝并电场频率、电场强度以及电场类型对粉尘凝并效果的影响。实验结果表明:可以大幅度降低粒径在0.3~0.5μm的粉尘百分比;有效增加粒径>1μm的粉尘百分比;可以有效提高模拟电除尘器对细小颗粒粉尘的捕集效率,有望减少电除尘器的本体体积。     

电捕法在炭素焙烧炉烟气净化中的应用

针对炭素焙烧炉的烟气特点,采用雾化水预处理和电捕焦油技术,对炭素厂焙烧炉烟气进行治理,达到高效净化有害气体—沥青烟的目的。