Development of Dynamic Filter of Cone and Plate Type for Sweeping Filter Cake of Ultrafine Particles

采用锥板式动态过滤器对水包油型乳状液进行微滤，考察了各种因素对过滤性能的影响。主要研究结果如下：1.验证了锥板式动态过滤器的优越性，由于动态过滤器具有较高的清扫性能，可实现长期高速过滤.对不同条件下的锥板式动态过滤进行了试验研究，得出以下结论：（1）对于形成高压缩性滤饼的浆料，压力的优化至关重要。(2)随着锥筒转速的提高，过滤速率显著提高。然而，必须考虑最佳转速与降低能耗的组合。(3)带槽锥板强化了滤室内的紊流，从而显著提高了过滤速率.进行了两种类型的实验。研究了两种情况下的过滤行为，即不将滤液循环到浆料槽的过滤，其中浆料浓度随时间增加，以及将滤液循环到浆料槽的过滤，使得浆料浓度可以保持恒定。结果发现，即使在相同的浆液浓度下比较两者的过滤速率，前者的过滤速率也小于后者的平衡过滤速率。在有循环的过滤情况下，当滤饼形成速率与滤饼去除速率平衡时达到现场稳定状态，而在无循环的过滤中，由于浓度增加，滤饼形成逐渐进行的伪稳定状态一直保持。这样，这两种类型之间的机理差异带来了过滤速率的差异。

In this study, microfiltration of oil-in-water emulsion was conducted using dynamic filter of cone and plate type, and the effects of various factors on filtration properties were investigated. The results are summarized as follows :1. The advantage of dynamic filter of cone and plate type was verified and high-speed filtration was resulted over the long-term periods due to the high sweeping performance of the dynamic filter.2. Dynamic filtration of the cone and plate type was conducted under various conditions, and the following conclusions were obtained :(1) For slurry forming highly compressible cake, it is of importance to optimize the applied pressure.(2) The increase in the rotating speed of cone leads to a remarkable increase in the filtration rate. However, the optimal rotating speed in combination with a reduction of the energy consumption must be taken into consideration.(3) The grooved cone plate enhances the turbulent flow in the filter chamber, and thus improves the filtration rate significantly.3. Two types of experiments were carried out. The filtration behaviors are investigated for both filtration without circulation of filtrate to the slurry tank, in which the concentration of slurry increases with time, and filtration with circulation of filtrate to the slurry tank so that the concentration of slurry could be maintained constant. It was found that the filtration rate of the former is smaller than the equilibrium one of the latter even though both filtration rates are compared at the same slurry concentration. In case of filtration with circulation, the siteady state is reached when the rate of cake formation is at equilibrium with the rate of cake removal, while in filtration without circulation, the pseudo-steady state in which the cake formation progresses gradually is retained all the time because of the increasing concentration. In this way, the difference in mechanism between these two types brings about the difference in filtration rate.