Pure silicon carbide filtering membrane

Abstract

The invention belongs to the technical field of porous ceramic materials and their preparation and especially discloses a pure silicon carbide filtering membrane and a preparation method thereof. The pure silicon carbide filtering membrane has a high porosity, a low pressure drop, high strength, good thermal shock resistance and a high use temperature. The preparation method can be realized easily and can guarantee product performances. The pure silicon carbide filtering membrane comprises pure SiC, is a surface membrane layer obtained by pile-up and binding of fine SiC particles and has aperture sizes of 0.1 to 20 microns and membrane porosity of 25 to 50%. Fine SiC particles, silicon powder, a pore-forming additive and one or more organic resins as raw materials are prepared into a surface membrane layer by spraying or dipping and the surface membrane layer is dried and sintered to form the pure silicon carbide filtering membrane. The pure silicon carbide filtering membrane can be used in an oxidation atmosphere and in a reducing atmosphere, has strong acid corrosion and alkaline corrosion resistance, and can be used for various high / low temperature fluid filtering purification fields such as coal gasification chemical engineering, integrated gasification combined cycle (IGCC) and pressurized fluidized bed combustion (PFBC) coal gasification power generation, and high temperature flue gas, automobile exhaust and water purification.

Description

technical field [0001] The invention belongs to the technical field of porous ceramic materials and their preparation, and specifically relates to a pure silicon carbide filter membrane layer and a preparation method thereof. phase, has the characteristics of high porosity, low pressure drop, high strength, good thermal shock resistance, and high service temperature. The preparation method is easy to implement and can guarantee product performance. Background technique [0002] High-temperature ceramic filter materials generally work under various harsh environmental conditions. As a high-temperature ceramic filter material for gas purification, it is usually required to have: (1) High mechanical strength, high temperature resistance (300-900°C) and excellent medium corrosion resistance Performance; (2) High filtration accuracy, filtration gas velocity and low pressure drop; (3) Easy to blow back, stable operation, high filtration efficiency; (4) Good thermal stability, able...

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Problems solved by technology

[0004] However, at present, the most widely used silicon carbide filter materials in high-temperature gas filtration are clay and other oxides combined with SiC ceramics. The disadvantage is that the thermal conductivity is low, resulting in poor thermal shock resistance, which makes it difficult for ceramic filter materials to withstand large thermal load fluctuations; especially In the high-temperature coal gasification power generation technology (such as IGCC, PFBC), because the coal contains sodium silicate and NaCl components, the Na 2 Si 2 o 5 It will seriously corrode the oxide combined with silicon carbide filter material, resulting in the failure of the filter, but the research shows that the pure SiC ceramic material is not subject to the above corrosion, and the pure silicon carbide material can be used under high temperature oxidation and reduction atmosphere, but At present, there is little technology in the development of pure silicon carbide filter materials, and the shortcomings of the obtained products are low strength, uneven pore size distribution, low filtration efficiency, large filtration pressure drop, and difficult backflushing cleaning of the pore structure, which limits the application of silicon carbide filter materials. process

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