Electrostatic Dust Collection of Sub-micron Particles with the Aid of Electrostatic Agglomeration Promoted by Particle Vibration

借助颗粒振动促进静电团聚对亚微米颗粒进行静电集尘

基本信息

批准号：
12650261
负责人：
NAKAJIMA Yoji
金额：
$ 2.62万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

Detrimental sub-micron particles in flue gas are to be agglomerated electrostatically on charged core particles so that they can be effectively removed with conventional dust collectors.Sub-micron particles suspended in gas receive an attraction due to electrostatic polarization to the charged core particles. Our recent calculations by the re-expansion method have proved that the attraction is much pronounced by the higher order polarizations. In order to make use of the higher order polarizations effectively, however, it is necessary to convey the sub-micron particles very close to the charged core particles. A strong vibration of core particles or application of intense acoustic wave with suitable frequency produces the acoustic streaming, which entrains the sub-micron particles around the core particles to enhance the rate of agglomeration. To evaluate such an effect of vibration, we have used the method of matched asymptotic expansion to find a perturbation solution to Navier-Stoke … More s equation, the solution that predicts the induced acoustic streaming around a core particle vibrating with large amplitude. It is shown that the acoustic streaming greatly promotes the efficacy of polarization forces to capture sub-micron particles. Then the motion of a sub-micron particle around a vibrating core particle has been precisely simulated to obtain the agglomeration rate constant.For measuring the agglomeration constant, a newly invented apparatus tracks the changes in size and electrostatic charge of a single core particle, which agglomerates sub-micron particles supplied around the core particle from a mono-disperse aerosol generator. The measured results show that the practical agglomeration constants are very high ; they are typically twice the simulated values. This is because turbulence in the agglomeration cell takes the same role as the acoustic streaming and enhances considerably the agglomeration rate. This implies that the present method will provide a powerful means for collecting sub-micron particles in practical situations. Less

烟气中的有害亚微米颗粒应在带电的核心颗粒上静电结合，以便可以通过常规的灰尘收集器有效地去除它们。悬浮在气体中的sub-微微粒颗粒由于对带电的核心颗粒的静电偏振而引起的吸引力。我们最近通过重新扩张方法的计算已经证明了吸引力是高阶极化的明显。但是，为了有效地利用高阶极化，有必要传达非常接近带电的核心颗粒的亚微米颗粒。核心颗粒的强烈振动或使用合适频率的强烈声波的应用会产生声流，该声流将进入核心颗粒周围的亚微米颗粒以提高聚集速率。为了评估这种振动的效果，我们使用了匹配的不对称膨胀方法来找到用于Navier-Stoke的扰动解决方案……更多S方程，该方程可预测围绕大型放大器振动的核心粒子周围诱导的声流。结果表明，声流大大促进了极化力捕获亚微米颗粒的效率。然后，已经精确模拟了亚微米粒子在振动核心粒子周围的运动，以获得团聚速率的常数。对于测量团聚常数，新发明的设备跟踪了单个核心粒子的大小和静电电荷的变化，该核心粒子的大小和静电电荷在围绕核心粒子围绕核心粒子提供的核心粒子从单层甲状腺外生成生成的核心颗粒提供。测得的结果表明，实用的聚集常数非常高。它们通常是模拟值的两倍。这是因为聚集细胞中的湍流具有与声学流相同的作用，并大大提高了聚集速率。这意味着当前的方法将为在实际情况下收集亚微米颗粒提供强大的手段。较少的