Development of High Performance Filtration System for Hot Gas Cleaning

随着过滤的进行，粉尘聚集在陶瓷滤芯上，并在滤芯上形成尘饼层。过滤条件和颗粒特性影响着滤芯上的粉尘积聚量和形状。一旦形成尘饼，过滤器的外观就会发生变化，因此其周围的气流也会发生变化。这意味着流场和粉尘层的形状相互影响，并且它们随时间而变化，即，过滤性能随时间变化。为了阐明滤芯周围的流动和积聚过程随时间的变化，提出了一种新的分析方法。在温度为293 ~ 1123 K、压力为1 ~ 10大气压、填料为0.03 ~ 0.12、过滤速度为5 Ncm/s的条件下，计算结果表明，在任何过滤条件下，滤饼在元件上都形成不均匀的层，即：最大沉积出现在元件的前部，最小沉积出现在离前部大约120-150度处。温度升高时，它向前移动，压力升高时，它向后移动。随着压力、温度和堆积密度的增加，粉尘层的均匀性增加。元件的抽吸速度，即，过滤速度随着时间的推移而降低，这是由于累积的灰尘导致阻力增加。这也导致抑制了灰尘随时间在元件上的累积速率。这种效应在高压和高温下是显著的。此外，跨元件的压降随时间非线性地增加，并且当温度和压力高时，其显示出更高的压降。

As filtration goes on, dusts are collected on a ceramic filter element and form a dust cake layr on it. The filtration conditions and particle properties affect the accumulated amount and its shape on the element. Once dust cake is formed, the appearance of the filter changes and thus the flow around it also changes. This means that both flow field and the shape of dust layr interact with each other and they change with time, i.e., filtration performance changes with time. To elucidate the change in the flow around the filter element and accumulation process with time, a new analysis method has been proposed. Its capability has been demonstrated by solving them at filtration velocity of 5 Ncm/s varying gas temperature from 293 to 1123 K,pressure from 1 to 10 atmosphere and packing from 0.03 and 0.12.As a result, it is found that dust cake forms a non-uniform layr on the element at any filtration condition, i.e., the maximum deposition appears at the front of the element and the minimum is observed around 120-150 degree from the front. It shifts forward as temperature rises but backward as pressure rises. With the increasing pressure, temperature and packing density, the uniformity of the dust layr increases. Suction velocity to the element, i.e., filtration velocity, decreases with time because of the increase in the resistance due to the accumulated dust. This also results in the suppression of accumulation rate of dust on the element with time. This effect is significant at high pressure and high temperature. Furthermore, pressure drop across the element increases non-linearly with time and it shows higher drops when temperature and pressure are high.