Abstract: The deposition morphology of particles on filter material is critical to filter performance and the dust-cleaning frequency of dust collectors. A set of experimental systems were built in this study to deeply understand the deposition law of particles on the surface of PTFE filter material. This experiment compared the effects of filtration time, dust concentration, filtration velocity, especially moisture content on the deposition quality per unit area of particles and the average thickness of the dust cake, explored the applicability of the two deposition rates of particles, and adhesion efficiency of high moisture particles then deduced the thickness distribution model of dust cake with different moisture content. The force model between particles was derived to discuss the motion of particles. The self-gravity of subsequently deposited particles exerted pressure on previously deposited particles, the gravity of the upper dust layer, the drag force of the airflow on the particles, and the adhesion force between the particles jointly determined the movement trend of the particles. The experimental results showed that the deposition quality per unit area of high moisture dust was significantly lower than dry dust. When dust moisture content increased, the average thickness and deposition quality per unit area of dust cake was reduced and then increased. The deposition of high moisture dust was affected by adhesion force between particles, and the mass deposition rate and adhesion efficiency were the lowest when the moisture content of dust was 10%. The uniformity of dust cake was lower than dry dust cake when the moisture content was 9% and 13%. Once the adhesion force between high moisture particles can resist the compression effect of upper gravity, the particles were not easy to slide, and the structure of the dust cake was uniform. The uniformity was stable when the moisture content was 10%~12%, and the optimal moisture content was 10%.

Key words: high moisture viscous particles, deposition quality, dust cake thickness, deposition rate, dust cake uniformity

摘要： 过滤过程中颗粒物在滤料上的沉积形貌对除尘器过滤性能及清灰频率的确定至关重要。为深入了解颗粒物在聚四氟乙烯(PTFE)滤料表面的沉积规律，搭建了一套过滤实验系统，基于该实验系统对比了过滤时间、粉尘浓度、过滤风速和含水率对颗粒单位面积沉积质量及粉尘层平均厚度的影响，探究了两种沉积速率的适用性及高湿黏性颗粒的黏附效率，并推导了不同含水率粉尘层的厚度分布模型。通过建立沉积粉尘层内部颗粒间的受力模型，对颗粒的受力运动情况进行分析，后续沉积颗粒自身重力对先前沉积颗粒的压缩作用不可忽略，颗粒的运动趋势由上层粉尘层重力、气流对颗粒的曳力及颗粒间黏附力共同决定。实验结果表明，高湿粉尘较干燥粉尘单位面积沉积质量有所降低，随着粉尘含水率增大，粉尘层平均厚度和单位面积沉积质量呈先减小后增大的趋势；高湿粉尘的沉积受颗粒间黏附力大小的影响，粉尘含水率为10%时质量沉积速率和黏附效率最小；粉尘含水率为9%和13%时粉尘层均匀性较干燥粉尘层下降，当高湿颗粒间的黏附力可以抵抗上层重力的压缩作用时颗粒滑动减少，粉尘层结构均匀。含水率为10%~12%时粉尘层均匀性稳定，且含水率为10%时最佳。

关键词: 高湿黏性颗粒, 沉积质量, 粉尘层厚度, 沉积速率, 粉尘层均匀性