等离子体发生及其空气净化技术

发布时间：2018-06-14 22:15

本文选题：荷电量 + 电除尘　；参考：《浙江大学》2017年硕士论文

【摘要】：当前,我国大气污染问题越来越突出,2015年至今我国相继出台并落实各项环保政策,从燃煤锅炉等污染源上整治,取得了一定成效。传统的电除尘器对细颗粒物的除尘效果差,PM10和PM2.5则通过各种途径侵入室内,危害人类健康。目前,市面上的空气净化设备的净化效果差异较大。而等离子体放电时产生的高能离子流可以使颗粒物荷电和碰撞凝并,进而在电流体力和粘性力的共同作用下被收尘板捕集,产生的强氧化性活性粒子能够氧化降解有害有机、无机物和微生物气溶胶。本文以此为背景,针对等离子放电时的荷电能力、除尘效果、离子风驱动气流、电凝并效果、反电晕等特征进行研究,主要研究内容和实验结论如下:(1)单区电除尘器中颗粒物的荷电与除尘同步进行。线板反应器中颗粒物的荷电极性与微秒脉冲、直流电源的电压极性相同。颗粒物粒径越大,颗粒物荷电量越大。一定脉冲电压下,频率能够提高颗粒物的荷电量,但是频率的增加增强了离子风的负面影响,反而降低了除尘效果。在不同的直流和脉冲叠加形式下,颗粒物荷电量达到最大值时除尘效率并不是最佳值,那是因为电压提高颗粒物荷电量的同时也加强了二次流的负面作用。(2)线板式单区电除尘器中,在相同电压下,直流比脉冲产生更强的电流体力和涡流。线电极上下游区域靠近收尘板附近形成对称的双旋涡。不同一次流时,随着电压的增大,旋涡形成初期时EHD/Re2值为1～20之间,线电极附近的电场强度最强,涡流最剧烈。两种电源叠加时,总叠加电压一定时,直流基电压越大,湍流现象越明显,更易形成旋涡。(3)双区电除尘器中先进行预荷电再除尘。一定的电压范围内,提高收尘电压和荷电电压,均能提高收尘效率。当收尘电压高于一定数值时,收尘板边缘类似尖端放电,强电场产生的离子风会阻碍颗粒物驱进收尘板进行除尘。在同样的收尘电压下,相比于线板电除尘器,板板电除尘器中不仅可以提供匀强电场,而且不易产生剧烈的离子风。(4)采用交错布置的线线结构作为电凝并反应器,施加直流、脉冲和交流高压均能起到凝并效果,提高收尘效率,效果由大到小为:交流脉冲直流,直流高压凝并对不同粒径的颗粒物凝并效果大致相同,收尘效率平均提高5%,脉冲高压凝并大大提高了小粒径颗粒物的凝并效果,收尘效率平均提高13%。交流高压凝并对大小粒径的颗粒物均大大提高了收尘效率,平均提高10%。(5)等离子体放电时对气流具有推动作用,针筒、针孔和针网三种结构放电时形成的气流最大速度由大到小为:针筒针网针孔,分别为2m/s、1.4m/s和1m/s。且在靠近反应器下游的较小区域形成气流高速运动,远离该区域气流速度骤降。(6)高比电阻的多孔蜂窝陶瓷能进行稳定的反电晕放电,且反电晕放电时多孔蜂窝陶瓷前后均有明显的气流流动,可用作辅助气流驱动动力。相同的峰值电压下,脉冲高压相比直流高压不易于产生反电晕放电;直流叠加脉冲高压时,总叠加电压一定时,其中直流电压越大,产生反电晕越明显;一定的直流电压下产生的反电晕情况下,施加额外的脉冲高压并不能抑制反电晕的产生,反而使反电晕放电更剧烈。
[Abstract]:At present, the problem of air pollution in China is becoming more and more prominent. Since 2015, our country has promulgated and implemented various environmental protection policies, and has achieved certain results from the pollution sources such as coal-fired boilers. The traditional electrostatic precipitator has a bad effect on the dust removal of fine particles. PM10 and PM2.5 invade the indoor environment through various ways and endanger human health. The purification efficiency of the air purification equipment is very different, and the high energy ion flow produced by the plasma discharge can make the particles charged and collided with the particles, and then be trapped by the dust plate under the joint action of current and stickiness. The strong oxidizing active particles can oxidize and degrade harmful organic, inorganic and microbial gas. According to this background, the main research contents and experimental conclusions are as follows: (1) the charge of particles in the single area electrostatic precipitator and the charge of particles in the wire plate reactor. With the micro second pulse, the voltage polarity of the DC power supply is the same. The larger the particle size, the greater the charge of the particles. The frequency can increase the charge of the particles under a certain pulse voltage, but the increase of the frequency increases the negative effect of the ion wind, but reduces the effect of dust removal. In the form of different DC and pulse superposition, the particle charge is in the form of different DC and pulse superposition. The dedusting efficiency is not the best value when the electric quantity reaches the maximum. That is because the voltage increases the charge of the particles and also strengthens the negative effect of the two flow. (2) the direct current pulse produces stronger current and vorticity at the same voltage, and the downstream area on the line electrode is near the dust plate. Symmetrical double vortices. With the increase of the voltage, the EHD/Re2 value of the vortex is 1~20 when the voltage increases. The electric field near the line electrode is the strongest and the swirl is the most intense. When the two kinds of power superposition, the larger the overlay voltage is, the greater the DC base voltage is, the more obvious the turbulence phenomenon is, and the more easily the vortex is formed. (3) the first two zone electrostatic precipitator is first. In a certain voltage range, increasing the dust voltage and the charge voltage can increase the dust collecting efficiency. When the collecting voltage is higher than a certain value, the edge of the dust collector is similar to the tip discharge. The ion wind produced by the strong electric field will prevent the particles from driving into the dust collector. The electrostatic precipitator can not only provide a uniform electric field, but also not easily produce an intense ion wind. (4) the interlaced line and line structure is used as a electrocoagulation and reactor, and the effect of DC, pulse and AC high pressure can be applied to improve the efficiency of dust collecting, and the effect is from the AC pulse DC, the DC high pressure condensate. The effect of coagulating on particles with different particle sizes is approximately the same, the efficiency of dust collecting is increased by 5%, and pulse high pressure coagulation has greatly increased the coagulation effect of small particle particles. The efficiency of dust collecting is improved by 13%. AC high pressure coagulation and the dust collecting efficiency is greatly increased to the particle size particles, and the average increase of 10%. (5) plasma discharge is improved. The maximum velocity of air flow formed during the discharge of the needle tube, pinhole and needle mesh is from large to small: 2m/s, 1.4m/s and 1m/s., and the airflow velocity is formed in the smaller area near the downstream of the reactor, which is far away from the velocity of air flow in the region. (6) the porous honeycomb ceramics with high specific resistance can be carried out. The stable reverse corona discharge, and the porous honeycomb ceramic before and after the corona discharge has obvious air flow, can be used as the auxiliary airflow driving force. Under the same peak voltage, the pulse high pressure is not easy to produce the back corona discharge compared with the DC high voltage. When the DC superposition pulse high pressure, the total overlay voltage is certain, the greater the DC voltage is, the production of the DC voltage is bigger. The more obvious the back corona is, the additional pulsed high pressure does not inhibit the production of the back corona in a certain reverse corona under a certain DC voltage, but instead makes the reverse corona discharge more intense.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU834.8

【参考文献】