Design, Fabrication And Characteristics Of Porous Gradient Ceramics Fiber Membrane For Purifying High Temperature Dust Gas

High temperature filter technique plays a significant role in the solutions of exhaust gas emissions and environment protection engineering. The preparation of ceramic filter materials is the key issues in the separation and purification of high temperature flows. In this study, ceramic filter films with pore gradient structure and excellent performances such as low filter resistance, high separation efficiency, good high temperature resistance, corrosion resistance and thermal shock resistance are prepared, which has a great significant to the purification of high temperature exhaust gas and the environment protection.Based on the large quantity of related references, considering the environmental requirements for the ceramic filter films with pore gradient structure and experimental conditions, the support material, category of ceramic fibers, high temperature binders and pore forming agents are chosen. According to the particle size of high temperature gas and the initial experimental results, the separation layer and transition layer of the ceramic fibers and the pore size of porous ceramic support are designed.The preparation of porous ceramic support for a ceramic fiber film application is investigated systematically. The ceramic support with good high temperature resistance and stability, high porosity (large pore size), low filter resistance, high bending strength is initially fabricated via a hot-pouring and vibration process. The effect of pore size on the properties of films is discussed.Filter tube ceramic composite with pore gradient structure which fulfills the high temperature gas purification requirements is prepared. The results suggest that the transition layer and separation layer of the ceramic fibers properties are affected obviously by the amount of fibers, length and diameter ratio of fibers, particle size of cordierite and the amount of binders. With increasing the amount of ceramic fibers, the porosity and pore size of transition layer and separation layer of the ceramic fibers increase, while the bending strength decreases apparently. With increasing the amount of binders, the porosity and pore size of transition layer and separation layer of the ceramic fibers decrease, while the bending strength increases. Ceramic fibers with high length and diameter ratio show better connecting behavior in their micropores structure.The dispersing processing of ceramic fibers is the prerequisite in the preparation of ceramic filter films. The results suggest that, by using a mechanical stir, ceramic fibers with good disperse effect are obtained by controlling the concentration of the dispersing media, the amount of dispersant, the stirring speed and time. It is reported that a vacuum filtration suction process is suitable for preparation of ceramic filter films. The uniform transition layer and separation layer of the ceramic fibers are obtained by controlling the concentration of the ceramic slurry, filtration suction pressure and time. The ceramic film is easily formed by using a high slurry concentration, but difficult to control its thickness and uniformity when the concentration goes too high. With increasing the filtration suction pressure, the thickness of the films increases, while the porosity and pore size decrease. The filtration suction time can only affect the film thickness to some extends.The experimental model is established in this study to test the filtration efficiency of the ceramic filter tube with pore gradient structure, the experimental parameters are chosen. The infiltration efficiency and the change of the filtration resistance are tested. The regeneration effect after cleaning by using this ceramic filter tube as a filtration component is carried out. The results suggest that the TGXM10 ceramic filter tube with pore gradient structure has a good purification effect and regeneration property after cleaning, which fulfills the application of the purification of high temperature exhaust gas.