Pure foam silicon carbide support membrane tube with three-gradient pore structure and preparation method

A silicon carbide foam film and silicon carbide foam technology, applied in the field of porous ceramic materials, can solve the problems of limiting the application process of silicon carbide filter materials, the pore structure is not easy to be blown back and cleaned, and the thermal shock resistance is poor, so as to achieve rich and uniform gradient pores The effect of structure, low cost and long service life

Active Publication Date: 2016-06-22
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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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
[0005] Secondly, most of the existing silicon carbide membrane tube supports are extruded or pressed by powder method, which are combined by accumulation and firing of coarse silicon carbide and adhesives. , so that the pressure drop of the membrane tube is large, and the backflush pressure is high during backflush regeneration, making regeneration difficult

Method used

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  • Pure foam silicon carbide support membrane tube with three-gradient pore structure and preparation method
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  • Pure foam silicon carbide support membrane tube with three-gradient pore structure and preparation method

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preparation example Construction

[0059] The preparation method of the pure foamed silicon carbide support film tube with three gradient pore structures of the present invention uses solid powder particles, organic polymer resin, curing agent, and organic solvent as basic materials, mixes and prepares slurry, and uses organic foam as a template, Prepare the support body precursor by impregnation method, carbonize and sinter at low temperature, infiltrate and sinter after processing and molding, and then purify at high temperature to obtain pure foam silicon carbide support with double gradient pore structure, use silicon carbide powder, silicon powder or silicon oxide powder, Pore-forming agent additives and organosilicon precursors are used to prepare the film layer raw materials, and the film layer is prepared on the surface by spraying or dipping. After drying, the finished film tube is obtained by sintering. The specific preparation steps are as follows:

[0060] (1) Raw material preparation for support mol...

Embodiment 1

[0082] Blend 5 μm silicon carbide powder, phenolic resin, p-toluenesulfonic acid, and ethanol in a mass ratio of 5:2:0.1:0.3, and ball mill after mechanical stirring to obtain a foam support body forming slurry.

[0083] Three types of polyurethane foam with pore diameters of 1mm, 2mm, and 3mm are selected as the inner layer, and cut into hollow cylinders with an outer diameter of Φ56mm (inner diameter Φ40mm)×300mm, and polyurethane foam with three pore sizes of 300μm, 400μm, and 500μm is used as the outer layer, and cut into an outer diameter of Φ60mm (Φ56mm) × 300mm hollow cylinder, the inner and outer polyurethane foams of different pore diameters are covered together to obtain 9 kinds of combined double-gradient organic foams (respectively 1mm and 300μm, 2mm and 300μm, 3mm and 300μm, 1mm and 400μm, 2mm and 400μm, 3mm and 400μm, 1mm and 500μm, 2mm and 500μm, 3mm and 500μm), impregnated into the molding slurry, centrifuged to remove excess slurry, dried and solidified at 120°...

Embodiment 2

[0088] The difference from Example 1 is that 10 μm silicon carbide powder, epoxy resin, urotropine, and formaldehyde are blended in a mass ratio of 4:1:0.2:0.2, and after mechanical stirring, ball milling to obtain a foam support body molding slurry material.

[0089] Select the same combination of several polyurethane foams as in Example 1, process and bond after dipping and molding, and pyrolysis and sintering.

[0090] The pyrolysis temperature is 1200°C, the heating rate is 1°C / min, and the protective atmosphere is argon. After natural cooling, it is taken out and put into the sintering furnace; the raw material selected in the infiltration reaction sintering is silicon, and the sintering and silicon infiltration are carried out under the condition of argon. The heating rate was 10° C. / min, the melt temperature was 1600° C., and the temperature was kept for 5 hours to obtain an impure foamed silicon carbide membrane tube support.

[0091] High-temperature purification tre...

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Abstract

Belonging to the field of porous ceramic materials, the invention in particular relates to a pure foam silicon carbide support membrane tube with a three-gradient pore structure and a preparation method thereof. According to the foam silicon carbide support membrane tube, a dual-gradient pore structure pure foam silicon carbide support and a surface film layer form a three-gradient filtration structure, the support is composed of a dual-gradient pore structure pure foam silicon carbide support, the average pore size of the outer layer is 300-500micrometers, the average pore size of the inner layer is 1-3mm, and the support porosity is 35-65%; the surface film layer is formed by combination of silicon carbide powder, the pore size is 50nm-20micrometers, and the film layer porosity is 35%-50%. The preparation method comprises the following steps in order: burdening, foam support molding, support sintering, film layer preparation and firing. The pure foam silicon carbide support membrane tube provided by the invention can be used in oxidizing atmosphere and reducing atmosphere, has strong acid and alkali corrosion resistance, and can be used for coal gasification chemical engineering and IGCC, PFBC coal gasification power generation, high temperature flue gas, automobile exhaust, water purification and other high and low temperature fluid filtration purification.

Description

technical field [0001] The invention belongs to the field of porous ceramic materials, in particular to a pure foam silicon carbide support membrane tube with a three-gradient pore structure and a preparation method thereof. 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 to withstand frequent high-pressure pulse cooling Thermal shock caused by blowback of gas. At the same time, according to the requirements of its application, the high-temperature ceramic filter must be able to withstand the i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D69/10B01D71/02B01D67/00
Inventor 张劲松田冲杨振明曹小明刘强
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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