Preparation And Characterization Of Porous Ceramics For Dust Removal And Desulfurization

The integrated process for high temperature coal gas cleaning has the advantages of simplified technological process, economized instrumental investigation and shorter cleaning cost. Nowdays, the technology is in the researching stage, and the fundamental theories are inadequate. This paper aims at combining organically the zinc ferrite desulfurizers with better desulfutizing property and porous ceramic pieces with high efficiency in eliminating dust, and researches the preparation processes of porous ceramic pieces.The micropowder of zinc ferrite was prepared successfully by the means of self-propagating combustion with advantages of simpleness, rapidness, cheapness and so on. The zinc ferrite sol was synthesized by sol-gel method, and the appropriate temperature of 900℃was determinated.The porous ceramic pieces used in the integrated process for high temperature gas desulfurization and dust removal were prepared by two processes. The first method named additive method was to directly adding the micropowder of zinc ferrite prepared by self-propagating combustion to the raw materials used to prepare porous ceramic piecess, and the porous ceramic pieces prepared were of normal porosity and lower bending strength.Various factors such as material granularity, high temperature adhesive, pore forming agent and temperature, which can affect the preparation of porous ceramic pieces were analyzed. The results show that Al₂O₃ powder with the diameter 50μm, 15% high temperature adhesive, and 10～25% active carbon used as pore forming agent are the optimal formula, and the pore distribution range of the porous ceramic pieces prepared is 5～20μm and the porosity is about 40%.The sulfidation-regeneration test was carried out with pore ceramics preparied in additive method. The results show the porosity and diameter distribution were seldom affected in the process.The second method was coating method-the surface of porous ceramic pieces was coverd by Dip-Coating with the zinc ferrite sol prepared by sol-gel, which can prevent the sintering of zinc ferrite in high temperature. In the process, the viscosity of the desulfurizer was controlled at 5～7mPa.s, then the porous ceramic pieces were coated twice. The results show that the first method is better by comparing. The porous ceramic pieces were characterized by SEM, XRD and so on. The influences of zinc ferrite desulfurizers on pore distribution and porosity of ceramic filtration elements were discussed especially. The results show that the desulfurizer has little effect on the porous ceramic pieces, thus doesn't influence basically the dust removal property of porous ceramic piecess, which is in favor of the further researches.