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

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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.