Development of High Performance Filtration System for Hot Gas Cleaning

随着过滤的进行，粉尘被收集在陶瓷滤芯上，并在其上形成粉尘饼层。过滤条件和颗粒性质会影响元素上的积累量及其形状。一旦形成粉尘块，过滤器的外观就会改变，因此周围的流动也会改变。这意味着流场和粉尘层的形状是相互作用的，并随时间变化，即过滤性能随时间变化。为了阐明滤芯周围的流动和堆积过程随时间的变化，提出了一种新的分析方法。在过滤速度为5Ncm/S、气体温度为293~1123K、压力为1~10个大气压、填料为0.03~0.12的条件下，对其进行了求解。结果表明，在任何过滤条件下，粉尘饼在元件上形成了一层不均匀的层，即最大沉积量出现在元件的前端，最小的沉积量出现在距元件正面120-150度左右。它随着温度的升高而向前移动，但随着压力的上升而向后移动。随着压力、温度和堆积密度的增加，粉尘层的均匀性增加。由于积尘导致阻力增加，对元件的吸入速度，即过滤速度，随着时间的推移而减小。这也导致了随着时间的推移，粉尘在元素上的累积速率被抑制。这种影响在高压和高温下是显著的。此外，元件上的压降随时间呈非线性增加，且在温度和压力较高时表现出更大的压降。

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.