技术领域technical field
本发明属于多孔陶瓷材料领域，具体为一种具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管及其制备方法。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.
背景技术Background technique
高温陶瓷过滤材料一般都在各种苛刻的环境条件下工作，作为气体净化用高温陶瓷过滤材料通常要求具有：(1)高的机械强度、耐高温(300～900℃)和优良的耐介质腐蚀性能；(2)高的过滤精度和过滤气速以及低的压力降；(3)易于反吹、操作稳定、过滤效率高；(4)具有良好的热稳定性能，能够承受频繁的高压脉冲冷气体的反吹造成的热冲击。同时，根据其应用场合要求，高温陶瓷过滤器必须能承受气流化学特性变化的影响组分变化的影响、喷入极细尘粒时振动的影响，并保持较高的除尘效率，保持高流量等要求。选择的陶瓷材料不仅具有热的化学、机械稳定性，还应具有耐用性和高的可靠性；尤其在高温高压条件下，当存在气相硫、碱、氯元素腐蚀的情况时，还要求陶瓷材料具有高的化学稳定性。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 influence of changes in the chemical properties of the airflow, the influence of component changes, the influence of vibration when spraying very fine dust particles, and maintain a high dust removal efficiency and high flow rate, etc. Require. The selected ceramic material should not only have thermal chemical and mechanical stability, but also have durability and high reliability; especially under high temperature and high pressure conditions, when there is corrosion of gaseous sulfur, alkali, and chlorine elements, ceramic materials are also required Has high chemical stability.
首先，高温陶瓷过滤材料的过滤性能、高温热稳定性和安定性能以及长周期运行的可靠性能，是高温陶瓷过滤材料设计的关键。具有过滤、脱硫或脱硝多功能一体化的高温陶瓷过滤材料将是气体净化材料进一步发展方向。在各类陶瓷过滤材料中，以SiC陶瓷最有发展前景，因为SiC较氧化物陶瓷具有高导热率、低膨胀系数、抗热冲击性能好、使用温度高(1000℃以上)的特点，因此在汽车尾气、煤化工、融熔金属等产业领域高温流体过滤方面的优选材料。First of all, the filtration performance, high temperature thermal stability and stability of high-temperature ceramic filter materials, and the reliability of long-term operation are the key to the design of high-temperature ceramic filter materials. High-temperature ceramic filter materials with multifunctional integration of filtration, desulfurization or denitrification will be the further development direction of gas purification materials. Among all kinds of ceramic filter materials, SiC ceramics have the most development prospects, because SiC has the characteristics of high thermal conductivity, low expansion coefficient, good thermal shock resistance and high service temperature (above 1000 ° C) compared with oxide ceramics. The preferred material for high-temperature fluid filtration in industrial fields such as automobile exhaust, coal chemical industry, and molten metal.
但目前在高温气体过滤方面应用最多的碳化硅过滤材料多为粘土等氧化物结合SiC陶瓷，缺点是导热率低，导致抗热冲击性能差，使得陶瓷过滤材料难以承受大的热负荷波动；特别是在高温煤气化发电技术(如IGCC、PFBC)中，因煤中含有硅酸钠、NaCl成份，煤炭燃烧后转化成的Na2Si2O5会严重腐蚀氧化物结合碳化硅过滤材料，导致过滤器的破坏失效，而研究表明纯净的SiC陶瓷材料却不受到上述腐蚀，同时纯质碳化硅材料在高温氧化及还原气氛下都可以使用，但是目前在纯质碳化硅过滤材料研制方面技术少，所得制品强度低、孔径分布不均匀、过滤效率不高、过滤压降大、孔隙结构不易于反吹清洗的缺点，限制碳化硅过滤材料的应用进程。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, the Na 2 Si 2 O 5 converted into Na2 Si2 O5 after coal combustion will seriously corrode the oxide-bonded silicon carbide filter material, resulting in The damage of the filter fails, but research shows that pure SiC ceramic materials are not subject to the above corrosion, and pure silicon carbide materials can be used in high-temperature oxidation and reducing atmospheres, but there are few technologies in the development of pure silicon carbide filter materials , the resulting products have low strength, uneven pore size distribution, low filtration efficiency, large filtration pressure drop, and poor pore structure that is not easy to backflush and clean, which limits the application process of silicon carbide filter materials.
其次，现有碳化硅膜管支撑体多为粉末法挤出或压制成型，由粗颗粒碳化硅及粘接剂堆积烧成结合，其孔隙为颗粒堆积间隙形成，孔隙尺寸在几十个微米尺度，使得膜管压降大，并且反吹再生时反吹压力大，再生困难。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.
因此，使用温度高、耐各种介质腐蚀、强度高、高强度、低压降、易于再生、制备方法可靠、成本低的纯质碳化硅膜管过滤材料是人们所期待的。Therefore, a pure silicon carbide membrane tube filter material with high temperature, corrosion resistance to various media, high strength, high strength, low pressure drop, easy regeneration, reliable preparation method, and low cost is expected.
发明内容Contents of the invention
本发明的目的在于提供一种具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管及其制备方法，具体解决如上技术问题：The purpose of the present invention is to provide a pure foamed silicon carbide support film tube with a three-gradient pore structure and its preparation method, specifically solving the above technical problems:
本发明要解决的一个技术问题是：避免现有碳化硅过滤材料大多为粘土等氧化物部分结合的材料组成，提供一种纯质碳化硅过滤材料，材料组成为99wt％以上碳化硅，使得此种材料能在各种气氛条件下耐介质腐蚀能力更强。A technical problem to be solved by the present invention is: to avoid the existing SiC filter material being mostly composed of oxide parts such as clay, to provide a pure SiC filter material, the material is composed of more than 99wt% SiC, so that the This material is more resistant to medium corrosion under various atmospheric conditions.
本发明要解决的另一技术问题是：避免现有碳化硅膜管支撑体技术中的不足之处，提供一种具有双梯度泡沫孔隙结构，该种泡沫孔隙结构具有毫米级的孔隙，并且孔隙为三维联通，孔隙率大、低压降、易于再生，可重复使用的理想的纯质碳化硅多孔陶瓷膜管。Another technical problem to be solved by the present invention is to avoid the deficiencies in the existing silicon carbide membrane tube support technology, and provide a foam pore structure with a double gradient. This foam pore structure has millimeter-scale pores, and the pores It is an ideal pure silicon carbide porous ceramic membrane tube with three-dimensional connection, large porosity, low pressure drop, easy regeneration, and reusability.
本发明要解决的又一技术问题是：提供一种原料易得、配制简单、成型容易、生产周期短、成品率高、生产成本低的适于规模化生产的纯质碳化硅膜管的制备方法。Another technical problem to be solved by the present invention is to provide a preparation of a pure silicon carbide film tube suitable for large-scale production, which is easy to obtain raw materials, simple to prepare, easy to form, short in production cycle, high in yield and low in production cost. method.
为了解决碳化硅过滤材料制备中存在的技术问题，本发明所采取的技术方案是：In order to solve the technical problem existing in the preparation of silicon carbide filter material, the technical scheme that the present invention takes is:
一种具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管，三梯度孔隙结构泡沫碳化硅膜管的组成为纯质SiC，由支撑体层及表面膜层构成梯度过滤结构；其中，支撑体由双梯度孔隙结构纯质泡沫碳化硅支撑体构成，外层平均孔径300～500μm，内层平均孔径1～3mm之间；表面膜层由碳化硅粉末堆积结合而成，孔径50nm～20μm，膜管整体气孔率在35～65％之间。A pure foamed silicon carbide support membrane tube with a three-gradient pore structure, the composition of the three-gradient pore structure foam silicon carbide membrane tube is pure SiC, and a gradient filter structure is formed by a support layer and a surface film layer; wherein, the support It is composed of pure foamed silicon carbide support with double gradient pore structure, the average pore diameter of the outer layer is 300-500 μm, and the average pore diameter of the inner layer is between 1-3 mm; The overall porosity of the tube is between 35% and 65%.
所述的具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管，三梯度孔隙结构纯质泡沫碳化硅支撑体膜管的长度为100～2000mm，弯曲强度30～50MPa。The pure foamed silicon carbide support film tube with three gradient pore structures has a length of 100-2000 mm and a bending strength of 30-50 MPa.
所述的具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管，三梯度孔隙结构泡沫碳化硅支撑体膜管中，纯质SiC含量在99wt％以上。The pure foamed silicon carbide support membrane tube with a three-gradient pore structure, the content of pure SiC in the three-gradient pore structure foam silicon carbide support membrane tube is above 99 wt%.
所述的具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管的制备方法，以固体粉末颗粒、有机高分子树脂、固化剂、有机溶剂为基本材料，混合配制浆料，利用有机泡沫作为模板，浸渍法制备支撑体前驱体，低温碳化烧结，加工成型后溶渗烧结，再经高温纯化处理得双梯度孔隙结构纯质泡沫碳化硅支撑体后，采用碳化硅粉末、硅粉或氧化硅粉末、造孔剂添加剂及有机硅前驱体配制膜层原料，采用喷涂或浸渍方法表面制备膜层，经干燥后，烧结得到成品膜管。The preparation method of the pure foamed silicon carbide support film tube with a three-gradient pore structure 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 , the impregnation method to prepare the support body precursor, low-temperature carbonization and sintering, infiltration and sintering after processing and molding, and then high-temperature purification treatment to obtain a pure foamed silicon carbide support with double gradient pore structure, using silicon carbide powder, silicon powder or silicon oxide powder , pore-forming agent additives, and organic silicon precursors to prepare film layer raw materials, and prepare film layers on the surface by spraying or dipping methods. After drying, sintering to obtain finished film tubes.
所述的具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管的制备方法，具体制备步骤如下：The specific preparation steps of the preparation method of the pure foamed silicon carbide support film tube with a three-gradient pore structure are as follows:
(1)支撑体成型原料准备(1) Raw material preparation for support molding
将固体粉末颗粒、有机高分子树脂、固化剂、有机溶剂按质量比例为(5～4)：(2～1)：(0.1～0.2)：(0.3～0.2)共混，经机械搅拌后球磨得浆料；Blend the solid powder particles, organic polymer resin, curing agent, and organic solvent in a mass ratio of (5~4):(2~1):(0.1~0.2):(0.3~0.2), and ball mill after mechanical stirring get slurry;
有机泡沫采用聚氨酯泡沫，内层选用泡沫平均孔径为1～3mm之间，外层选用泡沫孔径为300～500μm；The organic foam adopts polyurethane foam, the inner layer uses foam with an average pore size of 1-3 mm, and the outer layer uses foam with a pore size of 300-500 μm;
固体粉末颗粒是碳化硅粉、硅粉或者二者混合粉末；有机高分子树脂选自环氧树脂、酚醛树脂和糠醛树脂之一种或两种以上；固化剂为：对甲苯磺酸、乌洛脱品、草酸或柠檬酸；有机溶剂为乙醇或甲醛；The solid powder particles are silicon carbide powder, silicon powder or a mixture of the two; the organic polymer resin is selected from one or more of epoxy resin, phenolic resin and furfural resin; the curing agent is: p-toluenesulfonic acid, urethane Depin, oxalic acid or citric acid; organic solvent is ethanol or formaldehyde;
(2)支撑体成型(2) Support body forming
首先将内层需要的泡沫切割成需要尺寸的空心圆柱状，外层泡沫切割成1～2mm的薄壁空心圆柱，并使得外层空心圆柱内径等于内层泡沫外径，然后将两者套在一起，在步骤(1)中准备好的料浆中浸泡，取出并通过离心、气吹的方法去除多余料浆，保持泡沫开孔，烘干固化，然后重复上述过程，得到所需固相体积分数的双梯度孔隙结构纯质泡沫碳化硅支撑体前驱体短管，其中固相体积分数控制在35～65％之间，烘干固化温度为120～180℃；First, cut the foam required for the inner layer into a hollow cylinder of the required size, and cut the outer foam into a thin-walled hollow cylinder of 1-2 mm, and make the inner diameter of the outer hollow cylinder equal to the outer diameter of the inner foam, and then put the two on Together, soak in the slurry prepared in step (1), take it out and remove the excess slurry by centrifugation and air blowing, keep the foam open, dry and solidify, and then repeat the above process to obtain the required solid phase volume Fractional double-gradient pore structure pure foam silicon carbide support precursor short tube, in which the solid phase volume fraction is controlled between 35-65%, and the drying and curing temperature is 120-180°C;
(3)拼接成型(3) Splicing and molding
将(2)步骤得到的支撑体前驱体短管机械加工成可相互插接的结构，利用同种料浆作为粘接剂，将支撑体前驱体短管插接粘接成需要尺寸的泡沫支撑体，然后热解，再经熔渗烧结的组成为残余Si及SiC的泡沫碳化硅支撑体；Machining the short tube of the support body precursor obtained in step (2) into a structure that can be inserted into each other, using the same slurry as an adhesive, inserting and bonding the short tube of the support body precursor into a foam support of the required size body, then pyrolyzed, and then infiltrated and sintered to form a foamed silicon carbide support of residual Si and SiC;
(4)高温纯化处理(4) High temperature purification treatment
将(3)得到的非纯质泡沫碳化硅支撑体进行在高温下，引入碳气氛处理，使得残余Si与碳气氛反应形成碳化硅，得到双梯度孔隙结构纯质泡沫碳化硅支撑体；The impure foamed silicon carbide support obtained in (3) is treated at a high temperature by introducing a carbon atmosphere, so that the residual Si reacts with the carbon atmosphere to form silicon carbide, and a pure foamed silicon carbide support with a double gradient pore structure is obtained;
所述高温纯化处理过程中，工艺过程和工艺参数如下：碳气氛采用乙炔或甲烷与氩气或氦气按体积比例为1:1组成，温度为1800～1950℃，升温速率为10～20℃/分钟，保温0.5～5小时，得双梯度孔隙结构纯质泡沫碳化硅支撑体；In the high-temperature purification process, the process and process parameters are as follows: the carbon atmosphere is composed of acetylene or methane and argon or helium in a volume ratio of 1:1, the temperature is 1800-1950°C, and the heating rate is 10-20°C /min, heat preservation for 0.5 to 5 hours, to obtain a pure foamed silicon carbide support with a double gradient pore structure;
(5)膜层原料准备(5) Raw material preparation for film layer
将碳化硅粉末、硅粉或氧化硅粉末、有机硅前驱体、造孔剂添加剂、有机溶剂按质量比例为(8～6)：(2～1)：(2～1)：(2～1)：(5～8)共混，经机械搅拌后球磨得膜层浆料；Silicon carbide powder, silicon powder or silicon oxide powder, organosilicon precursor, pore-forming agent additive, and organic solvent are (8-6): (2-1): (2-1): (2-1 ): (5-8) blending, after mechanical stirring, ball milling to obtain film layer slurry;
(6)表面膜层制备(6) Preparation of surface film layer
在(4)步骤得到的双梯度孔隙结构纯质泡沫碳化硅支撑体表面采用刷涂方法进行膜底层均匀涂覆后，再采用喷涂工艺进行；After the surface of the pure foamed silicon carbide support with double gradient pore structure obtained in step (4) is uniformly coated by brushing, the spraying process is then used;
(7)膜层烧结(7) Film layer sintering
将涂覆表面膜层后的膜管预制体在真空、氩气或其它惰性气体的保护气氛下，烧结，升温速率1～10℃/分钟，升温至1000～1400℃，保温0.5～1小时，自然降温冷却，得到具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管。Sinter the membrane tube prefabricated body coated with the surface film layer in a protective atmosphere of vacuum, argon or other inert gas, at a heating rate of 1-10°C/min, raise the temperature to 1000-1400°C, and keep it warm for 0.5-1 hour. Naturally lower the temperature and cool down to obtain a pure foamed silicon carbide support film tube with a three-gradient pore structure.
所述的具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管的制备方法，步骤(1)中，固体粉末颗粒粒度在5～20μm之间；有机高分子树脂选自环氧树脂、酚醛树脂和糠醛树脂之一种或两种以上；固化剂为对甲苯磺酸、乌洛托品、草酸或柠檬酸；有机溶剂为乙醇或甲醛。The preparation method of the pure foamed silicon carbide support film tube having a three-gradient pore structure, in step (1), the particle size of the solid powder is between 5 and 20 μm; the organic polymer resin is selected from epoxy resin, phenolic resin One or two or more of furfural resins; the curing agent is p-toluenesulfonic acid, urotropine, oxalic acid or citric acid; the organic solvent is ethanol or formaldehyde.
所述的具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管的制备方法，步骤(3)中：The preparation method of the pure foamed silicon carbide support membrane tube having a three-gradient pore structure, in step (3):
热解的工艺过程和工艺参数如下：氩气、氮气或其它惰性气体的保护气氛，或者在真空条件下，升温速率1～10℃/分钟，升温至800～1200℃，保温0.5～2小时，生成双梯度孔隙结构纯质泡沫碳化硅支撑体；The process and process parameters of pyrolysis are as follows: protective atmosphere of argon, nitrogen or other inert gases, or under vacuum conditions, heating rate is 1-10°C/min, the temperature is raised to 800-1200°C, and the temperature is kept for 0.5-2 hours. Generate a pure foamed silicon carbide support with a dual-gradient pore structure;
熔渗烧结的工艺过程和工艺参数如下：熔渗反应烧结中选用的原料为硅，在氩气、氮气或其它惰性气体的保护气氛下烧结渗硅，或者在真空条件下进行烧结渗硅，升温速率为5～15℃/分钟，熔体温度为：1600～1900℃，保温0.5～5小时，得非纯质泡沫碳化硅膜管支撑体。The process and process parameters of infiltration sintering are as follows: the raw material used in infiltration reaction sintering is silicon, and silicon infiltration is sintered under a protective atmosphere of argon, nitrogen or other inert gases, or sintered and silicon infiltrated under vacuum conditions. The rate is 5-15° C./min, the melt temperature is 1600-1900° C., and the temperature is maintained for 0.5-5 hours to obtain an impure foamed silicon carbide membrane tube support.
所述的具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管的制备方法，步骤(5)中，碳化硅粉末粒度在0.5～100μm之间，硅粉或者氧化硅粉末粒度在0.5～20μm之间；有机硅前驱体为三乙基硅烷、四甲基硅烷；机溶剂为甲苯或二甲苯，造孔添加剂为聚乙烯醇PVA或甲基纤维素。In the preparation method of the pure foamed silicon carbide support film tube with a three-gradient pore structure, in step (5), the particle size of the silicon carbide powder is between 0.5 and 100 μm, and the particle size of the silicon powder or silicon oxide powder is between 0.5 and 20 μm. Organosilicon precursors are triethylsilane and tetramethylsilane; organic solvents are toluene or xylene, and pore-forming additives are polyvinyl alcohol PVA or methylcellulose.
所述的具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管的制备方法，步骤(6)中，喷涂的工艺过程如下：利用气体喷枪将浆料喷涂在旋转的预制支撑体上，通过调节支撑体与喷枪之间相对位移速度控制膜层厚度，干燥后得到表面膜层。In the preparation method of the pure foamed silicon carbide support film tube with a three-gradient pore structure, in step (6), the spraying process is as follows: the slurry is sprayed on the rotating prefabricated support by using a gas spray gun, and by adjusting The relative displacement speed between the support body and the spray gun controls the thickness of the film layer, and the surface film layer is obtained after drying.
所述的具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管的制备方法，步骤(7)中，表面膜层厚度在50～500μm之间。In the preparation method of the pure foamed silicon carbide support film tube with a three-gradient pore structure, in step (7), the thickness of the surface film layer is between 50 and 500 μm.
本发明具有如下的优点和突出效果：The present invention has following advantage and outstanding effect:
1.本发明的纯质碳化硅膜管具有单一的碳化硅组成，保证了材料在各种高温介质下的抗腐蚀性能，尤其在氧化物结合碳化硅过滤材料不适宜使用的还原气氛及高碱腐蚀环境下，稳定性良好，膜层和支撑体组成的统一可保证两者的协同一致性，确保材料长使用寿命。1. The pure silicon carbide membrane tube of the present invention has a single silicon carbide composition, which ensures the corrosion resistance of the material in various high-temperature media, especially in the reducing atmosphere and high alkali that are not suitable for use in oxide-bonded silicon carbide filter materials. In a corrosive environment, the stability is good, and the unity of the composition of the film layer and the support body can ensure the synergy and consistency of the two, and ensure the long service life of the material.
2.本发明的三梯度孔隙结构纯质泡沫碳化硅膜管具有丰富均匀的梯度孔隙结构，双梯度孔隙结构纯质泡沫碳化硅支撑体的大孔隙结构保证了材料使用中低压降、高渗透率，并且易于再生，表面膜层的精细孔隙结构保证材料具有很好的过滤精度和过滤效率，并利于反吹清洗的实现，再生容易，可重复使用。2. The three-gradient pore structure pure foamed silicon carbide membrane tube of the present invention has a rich and uniform gradient pore structure, and the large pore structure of the double-gradient pore structure pure foamed silicon carbide support ensures low pressure drop and high permeability in the use of materials , and easy to regenerate, the fine pore structure of the surface film layer ensures that the material has good filtration accuracy and filtration efficiency, and facilitates the realization of backflushing cleaning, easy regeneration, and can be reused.
3.本发明的三梯度孔隙结构纯质泡沫碳化硅膜管晶粒结合方式为反应生成碳化硅结合原始碳化硅颗粒，二者性质上的一致保证晶粒间结合牢固，保证材料具有高的强度和抗热冲击性能。3. The three-gradient pore structure pure foamed silicon carbide membrane tube of the present invention combines grains in the form of reaction-generated silicon carbide combined with original silicon carbide particles. The consistency of the properties of the two ensures that the grains are firmly bonded and the material has high strength. and thermal shock resistance.
4.本发明的三梯度孔隙结构纯质泡沫碳化硅膜管制备方法工艺控制灵活，可根据需要设计不同规格的产品，生产周期短，成本低，易于实现，能够保障产品性能。4. The preparation method of the pure foamed silicon carbide membrane tube with three-gradient pore structure of the present invention has flexible process control, can design products of different specifications according to needs, has short production cycle, low cost, is easy to realize, and can guarantee product performance.
5.本发明提供的三梯度孔隙结构纯质泡沫碳化硅膜管材料应用领域广，在氧化、还原、高氯、碱、硫、硅等气氛下可长时使用，更可在1300℃的高温下使用，可用于煤化工及高温煤气化发电技术粗煤气过滤、高温锅炉等各种工业烟气、还可用于污水过滤处理。5. The three-gradient pore structure pure foam silicon carbide membrane tube material provided by the present invention has a wide range of applications. It can be used for a long time in the atmosphere of oxidation, reduction, high chlorine, alkali, sulfur, silicon, etc., and can be used at a high temperature of 1300 ° C. It can be used in coal chemical industry and high temperature coal gasification power generation technology crude gas filtration, high temperature boiler and other industrial flue gas, and can also be used for sewage filtration treatment.
总之，该种纯质碳化硅膜管具有由双梯度孔隙结构纯质泡沫碳化硅支撑体及表面膜层组成的三梯度孔隙结构，组成为纯质碳化硅，不存在氧化物等结合相，具有高通孔隙率、低压降、强度高、抗热冲击性能好、使用温度高、易于反吹再生的显著特点，制备方法易于实现，能够保证产品性能。In short, this kind of pure silicon carbide membrane tube has a three-gradient pore structure composed of a double-gradient pore structure pure foam silicon carbide support and a surface film layer. The composition is pure silicon carbide, and there is no binding phase such as oxides. The outstanding characteristics of high porosity, low pressure drop, high strength, good thermal shock resistance, high service temperature, and easy back-blowing regeneration, the preparation method is easy to implement, and can guarantee product performance.
附图说明Description of drawings
图1三梯度孔隙结构纯质泡沫碳化硅膜管XRD衍射图。Fig. 1 XRD diffraction pattern of pure foamed silicon carbide film tube with triple gradient pore structure.
图2三梯度孔隙结构纯质泡沫碳化硅膜管支撑体双梯度结构。Fig. 2 Three-gradient pore structure The double-gradient structure of the pure foamed silicon carbide membrane tube support.
图3a-b三梯度孔隙结构纯质泡沫碳化硅膜管表面膜层与泡沫结合部(图3a)及膜层孔隙结构(图3b)。Figure 3a-b Three-gradient pore structure The junction of the membrane layer and the foam on the surface of the pure foam silicon carbide membrane tube (Figure 3a) and the pore structure of the membrane layer (Figure 3b).
图4三梯度孔隙结构纯质泡沫碳化硅膜管照片。Fig. 4 Photo of pure foam silicon carbide membrane tube with three gradient pore structure.
具体实施方式detailed description
在具体实施方式中，本发明的三梯度孔隙结构纯质泡沫碳化硅支撑体膜管为具有不同孔隙结构的三梯度纯质碳化硅材料烧制而成，包括双梯度孔隙结构纯质泡沫碳化硅支撑体和表面膜层。其中：In a specific embodiment, the three-gradient pore structure pure foam silicon carbide support film tube of the present invention is fired from three-gradient pure silicon carbide materials with different pore structures, including double-gradient pore structure pure foam silicon carbide Support body and surface film layer. in:
(1)支撑体层原料组分为(按质量份数计)：(1) The raw material components of the support layer are (by mass parts):
(2)表面膜层原料组分为(按质量份数计)：(2) The raw material components of the surface film layer are (by mass parts):
泡沫碳化硅支撑体制备组成原料中，有机树脂烧结过程中首先转变为碳源，与原料中硅粉反应烧结，能够为支撑体提供强度保证，再经高温纯化处理，使得其中残余Si相与烧结气氛中的C反应生成SiC，最终材料组成全部为原始碳化硅及反应生成碳化硅相，而生成碳化硅相起到结合原始碳化硅颗粒的作用，保证了材料的纯质化，见附图1XRD衍射图谱。由于泡沫碳化硅支撑体为双梯度结构，内层为大孔径，外层为微米级孔径，利于膜层涂覆，同时由有机泡沫材料具有三维网络连通的孔隙结构，确保了支撑体具有低压降，易于反吹的优点，见图2。In the preparation of raw materials for the preparation of foamed silicon carbide supports, the organic resin is first converted into a carbon source during the sintering process, and reacts and sinters with silicon powder in the raw materials, which can provide strength guarantee for the support, and then undergoes high-temperature purification treatment to make the residual Si phase and sintered The C in the atmosphere reacts to form SiC, and the final material composition is all original silicon carbide and the reaction produces a silicon carbide phase, and the formed silicon carbide phase plays a role in combining the original silicon carbide particles, ensuring the purity of the material, see Figure 1XRD Diffraction pattern. Since the foamed silicon carbide support has a double-gradient structure, the inner layer has a large pore size, and the outer layer has a micron-scale pore size, which is conducive to film coating. At the same time, the organic foam material has a three-dimensional network-connected pore structure, which ensures that the support has a low pressure drop. , the advantage of being easy to blow back, see Figure 2.
膜层制备原料组成中，有机硅前驱体在一定温度下分解形成碳化硅相，进而结合原始碳化硅颗粒，形成紧密的颗粒堆积结合，同时造孔剂的脱出，使得膜层内部形成孔隙，由于膜层和支撑体材质都为碳化硅，二者膨胀系数、抗高温气氛腐蚀性能的协同一致，对于提高材料强度、抗热冲击、高温稳定性和持久寿命起到良好的作用。In the composition of raw materials for film layer preparation, the organosilicon precursor decomposes at a certain temperature to form a silicon carbide phase, and then combines with the original silicon carbide particles to form a tight particle accumulation combination. Both the film layer and the support body are made of silicon carbide, and the expansion coefficient and high temperature atmosphere corrosion resistance of the two are synergistic, which plays a good role in improving material strength, thermal shock resistance, high temperature stability and long-lasting life.
本发明的三梯度孔隙结构纯质泡沫碳化硅支撑体膜管的制备方法，以固体粉末颗粒、有机高分子树脂、固化剂、有机溶剂为基本材料，混合配制浆料，利用有机泡沫作为模板，浸渍法制备支撑体前驱体，低温碳化烧结，加工成型后溶渗烧结，再经高温纯化处理得双梯度孔隙结构纯质泡沫碳化硅支撑体后，采用碳化硅粉末、硅粉或氧化硅粉末、造孔剂添加剂及有机硅前驱体配制膜层原料，采用喷涂或浸渍方法表面制备膜层，经干燥后，烧结得到成品膜管，具体制备步骤如下：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:
(1)支撑体成型原料准备(1) Raw material preparation for support molding
将固体粉末颗粒、有机高分子树脂、固化剂、有机溶剂按质量比例为(5～4)：(2～1)：(0.1～0.2)：(0.3～0.2)共混，经机械搅拌后球磨得浆料；Blend the solid powder particles, organic polymer resin, curing agent, and organic solvent in a mass ratio of (5~4):(2~1):(0.1~0.2):(0.3~0.2), and ball mill after mechanical stirring get slurry;
有机泡沫采用聚氨酯泡沫，内层选用有机泡沫平均孔径为1～3mm之间，外层选用有机泡沫孔径为300～500μm；The organic foam is polyurethane foam, the inner layer is made of organic foam with an average pore size of 1-3 mm, and the outer layer is made of organic foam with a pore size of 300-500 μm;
固体粉末颗粒是碳化硅粉、硅粉或者二者混合粉末，粉末粒径5～20μm之间；有机高分子树脂选自环氧树脂、酚醛树脂和糠醛树脂之一种或两种以上；固化剂为对甲苯磺酸、乌洛脱品、草酸或柠檬酸；有机溶剂为乙醇或甲醛；The solid powder particles are silicon carbide powder, silicon powder or a mixture of the two powders, and the particle size of the powder is between 5 and 20 μm; the organic polymer resin is selected from one or more of epoxy resin, phenolic resin and furfural resin; curing agent It is p-toluenesulfonic acid, urothene, oxalic acid or citric acid; the organic solvent is ethanol or formaldehyde;
(2)支撑体成型(2) Support body forming
首先将内层需要的有机泡沫切割成需要尺寸的空心圆柱状，外层有机泡沫切割成1～2mm的薄壁空心圆柱，并使得外层空心圆柱内径等于内层有机泡沫外径，然后将两者套在一起，在步骤(1)中准备好的料浆中浸泡，取出并通过离心、气吹的方法去除多余料浆，保持有机泡沫开孔，烘干固化，然后重复上述过程，得到所需体积分数的双梯度孔隙结构纯质泡沫碳化硅支撑体前驱体短管，其中固相体积分数控制在35～65％之间，烘干固化温度为120～180℃；First, cut the organic foam required for the inner layer into a hollow cylinder of the required size, and cut the outer organic foam into a thin-walled hollow cylinder of 1-2mm, and make the inner diameter of the outer hollow cylinder equal to the outer diameter of the inner organic foam, and then cut the two put them together, soak them in the slurry prepared in step (1), take them out and remove the excess slurry by means of centrifugation and air blowing, keep the organic foam open, dry and solidify, then repeat the above process to obtain the A short tube of a pure foam silicon carbide support precursor with a dual gradient pore structure that requires a volume fraction, in which the solid phase volume fraction is controlled between 35% and 65%, and the drying and curing temperature is 120°C to 180°C;
(3)拼接成型(3) Splicing and molding
将(2)步骤得到的支撑体前驱体短管机械加工成可相互插接的结构，利用同种料浆作为粘接剂，将支撑体前驱体短管插接粘接成需要尺寸的泡沫支撑体，然后热解，再经熔渗烧结的组成为残余Si及SiC的泡沫碳化硅支撑体。Machining the short tube of the support body precursor obtained in step (2) into a structure that can be inserted into each other, using the same slurry as an adhesive, inserting and bonding the short tube of the support body precursor into a foam support of the required size body, then pyrolyzed, and then infiltrated and sintered to form a foamed silicon carbide support of residual Si and SiC.
热解工艺为：氩气、氮气或其它惰性气体的保护气氛，或者在真空条件下，升温速率1～10℃/分钟，升温至800～1200℃，保温0.5～2小时。The pyrolysis process is: a protective atmosphere of argon, nitrogen or other inert gases, or under vacuum conditions, the heating rate is 1-10°C/min, the temperature is raised to 800-1200°C, and the temperature is kept for 0.5-2 hours.
烧结工艺为：熔渗反应烧结中选用的原料为硅，在氩气、氮气或其它惰性气体的保护气氛下烧结渗硅，或者在真空条件下进行烧结渗硅，升温速率为5～15℃/分钟，熔体温度为：1600～1900℃，保温0.5～5小时。The sintering process is as follows: the raw material used in the infiltration reaction sintering is silicon, and the silicon infiltration is sintered under the protective atmosphere of argon, nitrogen or other inert gas, or sintered and infiltrated with silicon under vacuum conditions, and the heating rate is 5～15℃/ minutes, the melt temperature is: 1600-1900°C, and the temperature is kept for 0.5-5 hours.
(4)高温纯化处理(4) High temperature purification treatment
将(3)得到的非纯质泡沫碳化硅支撑体进行在高温下，引入碳气氛处理，使得残余Si与碳气氛反应形成碳化硅，得双梯度孔隙结构纯质泡沫碳化硅支撑体。碳气氛采用乙炔或甲烷与氩气或氦气按体积比例为1:1组成，温度为1800～1950℃，升温速率为10～20℃/分钟，保温0.5～5小时，得双梯度孔隙结构纯质泡沫碳化硅支撑体。The impure foamed silicon carbide support obtained in (3) is treated at high temperature by introducing a carbon atmosphere, so that the residual Si reacts with the carbon atmosphere to form silicon carbide, and a pure foamed silicon carbide support with a double gradient pore structure is obtained. The carbon atmosphere is composed of acetylene or methane and argon or helium at a volume ratio of 1:1, the temperature is 1800-1950°C, the heating rate is 10-20°C/min, and the temperature is kept for 0.5-5 hours to obtain a pure double-gradient pore structure. Quality foam silicon carbide support body.
(5)膜层原料准备(5) Raw material preparation for film layer
将碳化硅粉末、硅粉或氧化硅粉末、有机硅前驱体、造孔剂添加剂、有机溶剂按质量比例为(8～6)：(2～1)：(2～1)：(2～1)：(5～8)共混，经机械搅拌后球磨得膜层浆料；Silicon carbide powder, silicon powder or silicon oxide powder, organosilicon precursor, pore-forming agent additive, and organic solvent are (8-6): (2-1): (2-1): (2-1 ): (5-8) blending, after mechanical stirring, ball milling to obtain film layer slurry;
碳化硅粉末粒度在0.5～100μm之间，硅粉或者氧化硅粉末粒度在0.5～20μm之间；有机硅前驱体为三乙基硅烷、四甲基硅烷；有机溶剂为甲苯或二甲苯，造孔添加剂为聚乙烯醇PVA或甲基纤维素。The particle size of silicon carbide powder is between 0.5 and 100 μm, and the particle size of silicon powder or silicon oxide powder is between 0.5 and 20 μm; the organosilicon precursor is triethylsilane and tetramethylsilane; the organic solvent is toluene or xylene, and the pores are formed The additive is polyvinyl alcohol PVA or methyl cellulose.
(6)表面膜层制备(6) Preparation of surface film layer
在(4)步骤得到的双梯度孔隙结构纯质泡沫碳化硅支撑体表面采用刷涂方法进行膜底层均匀涂覆后，再采用喷涂工艺进行；After the surface of the pure foamed silicon carbide support with double gradient pore structure obtained in step (4) is uniformly coated by brushing, the spraying process is then used;
(7)膜层烧结(7) Film layer sintering
将涂覆表面膜层后的膜管预制体在真空、氩气或其它惰性气体的保护气氛下，烧结，升温速率1～10℃/分钟，升温至1000～1400℃，保温0.5～1小时，自然降温冷却，得到具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管。Sinter the membrane tube prefabricated body coated with the surface film layer in a protective atmosphere of vacuum, argon or other inert gas, at a heating rate of 1-10°C/min, raise the temperature to 1000-1400°C, and keep it warm for 0.5-1 hour. Naturally lower the temperature and cool down to obtain a pure foamed silicon carbide support film tube with a three-gradient pore structure.
本发明中，泡沫碳化硅膜管的组成为纯质SiC，由双梯度孔隙结构纯质泡沫碳化硅支撑体层及表面膜层构成三梯度过滤结构；其中，支撑体为双梯度孔隙结构纯质泡沫碳化硅支撑体，具有三维网络连通的大孔隙结构，表面膜层由碳化硅粉末堆积结合而成，孔径0.1～20μm(优选为0.2～5μm)，膜管整体气孔率在35～65％之间。所述具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管的长度为100～2000mm，抗弯强度30～50MPa。所述具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管中，纯质SiC含量在99wt％以上，余量为杂质元素，材料内部晶粒结合完全由碳化硅颗粒自烧结结合，不存在粘土或其他氧化物结合相。In the present invention, the composition of the foamed silicon carbide membrane tube is pure SiC, and a three-gradient filtration structure is formed by a double gradient pore structure pure foam silicon carbide support layer and a surface film layer; wherein, the support body is a double gradient pore structure pure The foamed silicon carbide support has a large pore structure connected by a three-dimensional network. The surface film layer is formed by stacking silicon carbide powder, with a pore size of 0.1-20 μm (preferably 0.2-5 μm), and the overall porosity of the membrane tube is between 35-65%. between. The length of the pure foam silicon carbide support film tube with three gradient pore structures is 100-2000 mm, and the bending strength is 30-50 MPa. In the pure foamed silicon carbide support film tube with a three-gradient pore structure, the content of pure SiC is more than 99 wt%, and the balance is impurity elements. The internal grain bonding of the material is completely bonded by the self-sintering of silicon carbide particles, and there is no clay or other oxide bonded phases.
下面，通过实施例和附图对本发明进一步详细描述。Hereinafter, the present invention will be described in further detail through examples and accompanying drawings.
实施例1Example 1
将5μm碳化硅粉末、酚醛树脂、对甲苯磺酸、乙醇按质量比例为5：2：0.1：0.3共混，经机械搅拌后球磨得泡沫支撑体成型浆料。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.
分别选用1mm、2mm、3mm三种孔径聚氨酯泡沫为内层，切割成外径Φ56mm(内径Φ40mm)×300mm空心圆柱，选用300μm、400μm、500μm三种孔径聚氨酯泡沫为外层，切割成外径Φ60mm(Φ56mm)×300mm空心圆柱后，将不同孔径内外聚氨酯泡沫套在一起，得9种组合双梯度有机泡沫(分别为1mm和300μm、2mm和300μm、3mm和300μm、1mm和400μm、2mm和400μm、3mm和400μm、1mm和500μm、2mm和500μm、3mm和500μm)，浸渍成型浆料，离心去除多余浆料后，120℃烘干固化，重复以上浸渍烘干步骤，得到四种固相体积分数分别为35％、45％、55％、65％的双梯度孔隙结构纯质泡沫碳化硅支撑体前驱体短管，将上述短管加工成插接结构，并用同种浆料粘接接合起来，烘干固化，得1000mm、1500mm、2000mm三种长度支撑体预制体。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°C, and repeated the above steps of immersion and drying to obtain four solid phase volume fractions respectively 35%, 45%, 55%, and 65% double-gradient pore structure pure foam silicon carbide support precursor short tubes, the above short tubes are processed into plug-in structures, and bonded with the same slurry, baked Dry curing to obtain three types of support body preforms with lengths of 1000mm, 1500mm and 2000mm.
将上述加工后的支撑体预制体热解，温度800℃，升温速率5℃/分钟，保护气氛为氩气，自然降温取出后，装入烧结炉；熔渗反应烧结中选用的原料为硅，在真空条件下进行烧结渗硅，升温速率为5℃/分钟，熔体温度为：1900℃，保温0.5小时，得非纯质泡沫碳化硅膜管支撑体。Pyrolyze the above-mentioned processed support body prefabricated body at a temperature of 800°C, a heating rate of 5°C/min, and a protective atmosphere of argon, take it out after natural cooling, and put it into a sintering furnace; the raw material used in the infiltration reaction sintering is silicon, Carry out sintering and siliconizing under vacuum conditions, the heating rate is 5°C/min, the melt temperature is 1900°C, and the temperature is kept for 0.5 hours to obtain an impure foamed silicon carbide membrane tube support.
高温纯化处理，碳气氛采用甲烷与氩气按体积比例为1:1组成，温度为1800℃，升温速率为10℃/分钟，保温5小时，得到双梯度孔隙结构纯质泡沫碳化硅支撑体。High-temperature purification treatment, the carbon atmosphere is composed of methane and argon in a volume ratio of 1:1, the temperature is 1800°C, the heating rate is 10°C/min, and the temperature is kept for 5 hours to obtain a pure foam silicon carbide support with a double gradient pore structure.
得到材料强度主要由固相体积分数决定，35％、45％、55％、65％四种体积分数弯曲强度分别为35MPa、40MPa、45MPa、50MPa，测得支撑体5mm/s气体流速下压降损失在2％～5％之间，相互间差距较小。The strength of the obtained material is mainly determined by the volume fraction of the solid phase. The bending strengths of the four volume fractions of 35%, 45%, 55%, and 65% are 35MPa, 40MPa, 45MPa, and 50MPa respectively. The pressure drop of the support at a gas flow rate of 5mm/s is measured The loss is between 2% and 5%, and the gap between them is small.
实施例2Example 2
与实施例1不同之处在于，将10μm碳化硅粉末、环氧树脂、乌洛托品、甲醛按质量比例为4：1：0.2：0.2共混，经机械搅拌后球磨得泡沫支撑体成型浆料。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.
选用同实施例1相同的几种聚氨酯泡沫组合，浸渍成型后加工粘接，热解烧结。Select the same combination of several polyurethane foams as in Example 1, process and bond after dipping and molding, and pyrolysis and sintering.
热解温度1200℃，升温速率1℃/分钟，保护气氛为氩气，自然降温取出后，装入烧结炉；熔渗反应烧结中选用的原料为硅，在氩气条件下进行烧结渗硅，升温速率为10℃/分钟，熔体温度为：1600℃，保温5小时，得非纯质泡沫碳化硅膜管支撑体。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.
高温纯化处理，碳气氛采用丙烷与氩气按体积比例为1:1组成，温度为1900℃，升温速率为20℃/分钟，保温0.5小时，得到双梯度孔隙结构纯质泡沫碳化硅支撑体。High-temperature purification treatment, the carbon atmosphere is composed of propane and argon in a volume ratio of 1:1, the temperature is 1900°C, the heating rate is 20°C/min, and the temperature is kept for 0.5 hours to obtain a pure foam silicon carbide support with a double gradient pore structure.
得到材料强度及压降损失水平与实施例1基本相同。The obtained material strength and pressure drop loss level are basically the same as those in Example 1.
实施例3Example 3
表面膜层制备：Surface film preparation:
将碳化硅粉末(2μm)、硅粉(2μm)、三乙基硅烷、造孔剂添加剂(PVA)、甲苯按质量比例为8：2：2：1：5共混，经机械搅拌后球磨得膜层浆料。Blend silicon carbide powder (2μm), silicon powder (2μm), triethylsilane, pore-forming agent additive (PVA), and toluene in a mass ratio of 8:2:2:1:5, and ball mill it after mechanical stirring. Membrane slurry.
将得到的实施例1及实施例2中得到的双梯度孔隙结构纯质泡沫碳化硅支撑体表面刷涂一层膜层浆料，而后干燥打磨光滑，再用喷涂方法喷涂：利用气体喷枪将浆料喷涂在旋转的预制支撑体上，通过调节支撑体与喷枪之间相对位移速度控制膜层厚度，干燥后得到表面膜层。控制喷枪物料流速得三种厚度表面膜层，分别为50μm、300μm、500μm膜管。Brush the surface of the pure foamed silicon carbide support with dual gradient pore structure obtained in Example 1 and Example 2 with a layer of film layer slurry, then dry and polish it smooth, and then spray it with a spraying method: use a gas spray gun to spray the slurry The material is sprayed on the rotating prefabricated support body, the thickness of the film layer is controlled by adjusting the relative displacement speed between the support body and the spray gun, and the surface film layer is obtained after drying. Control the material flow rate of the spray gun to obtain three thicknesses of surface film layers, namely 50 μm, 300 μm, and 500 μm film tubes.
将涂覆表面膜层后的膜管在氩气的保护气氛下，烧结，升温速率5℃/分钟，升温至1200℃，保温1小时，得具有不同双梯度孔隙结构纯质泡沫碳化硅支撑体及膜层厚度的具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管。Sinter the film tube coated with the surface film layer under the protective atmosphere of argon, the heating rate is 5°C/min, the temperature is raised to 1200°C, and the temperature is kept for 1 hour to obtain a pure foam silicon carbide support with different double gradient pore structures. and membrane thickness with a three-gradient pore structure pure foam silicon carbide support membrane tube.
上述不同具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管膜层孔隙为0.3μm，孔隙率38％；压降测试水平表明，支撑体对于整体膜管压降水平影响不大，膜层厚度为主要影响因素，对应于50μm、300μm、500μm的膜层厚度，5mm/s气体流速下压降损失分别为7％、12％、23％。过滤精度测试结果，对于0.2μm粉末颗粒，精度分别为98％、99.5％、99.8％，材料耐温不低于1200℃。The above differences have a three-gradient pore structure pure foam silicon carbide support membrane tube membrane layer porosity is 0.3μm, porosity 38%; pressure drop test level shows that the support body has little effect on the pressure drop level of the overall membrane tube, the thickness of the membrane layer As the main influencing factor, corresponding to the film thickness of 50μm, 300μm, and 500μm, the pressure drop loss at the gas flow rate of 5mm/s is 7%, 12%, and 23%, respectively. According to the test results of filtration accuracy, for 0.2μm powder particles, the accuracy is 98%, 99.5%, and 99.8%, respectively, and the temperature resistance of the material is not lower than 1200°C.
实施例4Example 4
与实施例3膜层制备原料不同之处在于，将碳化硅粉末(10μm)、氧化硅粉(1μm)、四甲基硅烷、造孔剂添加剂(甲基纤维素)、二甲苯按质量比例为6：1：2：2：8共混，经机械搅拌后球磨得膜层浆料，支撑体选择及膜层涂覆方式与实施例3相同。The difference with the raw materials for the preparation of the film layer in Example 3 is that silicon carbide powder (10 μm), silicon oxide powder (1 μm), tetramethylsilane, pore-forming agent additive (methylcellulose), and xylene are 6: 1: 2: 2: 8 blending, after mechanical stirring, ball milling to obtain the film layer slurry, the selection of the support body and the coating method of the film layer are the same as in Example 3.
与实施例3烧结温度将涂覆表面膜层后的膜管在氩气的保护气氛下，烧结，升温速率2℃/分钟，升温至1400℃，保温0.5小时，得具有不同双梯度孔隙结构纯质泡沫碳化硅支撑体及膜层厚度的具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管。The sintering temperature of Example 3 is to sinter the membrane tube coated with the surface film layer under the protective atmosphere of argon gas, the heating rate is 2°C/min, the temperature is raised to 1400°C, and the temperature is kept for 0.5 hours to obtain pure tubes with different double-gradient pore structures. The pure foam silicon carbide support film tube with a three-gradient pore structure and a pure foam silicon carbide support body and a film layer thickness.
得到的具有三梯度孔隙结构纯质泡沫碳化硅支撑体膜管膜层孔隙为2μm，孔隙率40％；压降测试水平表明，支撑体对于整体膜管压降水平影响不大，膜层厚度为主要影响因素，对应于50μm、300μm、500μm的膜层厚度，5mm/s气体流速下压降损失分别为6％、9％、17％。过滤精度测试结果，对于0.2μm粉末颗粒，精度分别为85％、91％、95％，对于1μm粉末颗粒，精度分别为98％、99.2％、999.9％；材料耐温不低于1300℃。The obtained pure foamed silicon carbide support with a three-gradient pore structure has a membrane layer with a pore size of 2 μm and a porosity of 40%. The pressure drop test level shows that the support has little effect on the pressure drop level of the overall membrane tube, and the thickness of the membrane layer is The main influencing factors, corresponding to the film thickness of 50 μm, 300 μm, and 500 μm, the pressure drop loss at a gas flow rate of 5 mm/s is 6%, 9%, and 17%, respectively. According to the test results of filtration accuracy, for 0.2μm powder particles, the accuracy is 85%, 91%, 95%, and for 1μm powder particles, the accuracy is 98%, 99.2%, 999.9%; the temperature resistance of the material is not lower than 1300 ℃.
如图1所示，从三梯度孔隙结构纯质泡沫碳化硅膜管XRD衍射图可以看出，材料组成为纯质碳化硅，由反应生成β-SiC及α-SiC组成，其中β-SiC为反应生成相，起到结合原始α-SiC作用。As shown in Figure 1, it can be seen from the XRD diffraction pattern of the pure foamed silicon carbide film tube with three gradient pore structures that the material is composed of pure silicon carbide, which is composed of β-SiC and α-SiC formed by the reaction, where β-SiC is The reaction generates a phase, which plays a role in binding the original α-SiC.
如图2所示，从三梯度孔隙结构纯质泡沫碳化硅膜管支撑体双梯度结构可以看出，外层孔径具有<500μm，内层孔径>1mm，内层小孔径结构利于表面膜层涂覆，整体三维网络连通结构确保膜管具有低压降水平，并利于反吹再生。As shown in Figure 2, it can be seen from the dual-gradient structure of the pure foamed silicon carbide membrane tube support with a three-gradient pore structure, the outer layer pore diameter is <500 μm, the inner layer pore diameter is >1mm, and the inner layer small pore structure is conducive to surface film coating Covering, the overall three-dimensional network connection structure ensures that the membrane tube has a low pressure drop level and is conducive to backflush regeneration.
如图3a–b所示，从三梯度孔隙结构纯质泡沫碳化硅膜管表面膜层与泡沫结合部(图3a)及膜层孔隙结构(图3b)可以看出，表明膜层具有微米级孔隙结构，起到过滤作用，膜层与支撑体结合牢固。As shown in Figure 3a–b, it can be seen from the junction between the membrane layer and the foam on the surface of the pure foam silicon carbide membrane tube with three gradient pore structures (Figure 3a) and the pore structure of the membrane layer (Figure 3b), indicating that the membrane layer has a micron-scale The pore structure acts as a filter, and the membrane layer is firmly combined with the support.
如图4所示，从三梯度孔隙结构纯质泡沫碳化硅膜管照片可以看出，本发明制备的膜管制备方法可靠程度高，膜管变形率低，成品率高。As shown in Figure 4, it can be seen from the photos of the pure foamed silicon carbide membrane tube with three gradient pore structures that the membrane tube preparation method prepared by the present invention has high reliability, low deformation rate of the membrane tube, and high yield.
实施例结果表明，本发明提供了一种三梯度孔隙结构纯质泡沫碳化硅膜管及其制备方法，所述纯质碳化硅膜管具有由具有三维网路连通大孔径双梯度孔隙结构纯质泡沫碳化硅支撑体及精细表面膜层组成的三梯度孔隙结构，材料组成为纯质碳化硅，不存在氧化物等结合相，具有高通孔隙率、低压降、强度高、抗热冲击性能好、使用温度高、易于反吹再生的特点，可在氧化气氛下使用，也可以在还原气氛下使用，耐酸、碱腐蚀性能强，可用于煤气化化工及IGCC、PFBC煤气化发电、高温烟气、汽车尾气、水净化等各种高、低温流体过滤净化；所述制备方法依次包括配料、支撑体成型、膜层制备和烧成，其工艺简单，成本低，易于实现，能够保证产品性能。The results of the examples show that the present invention provides a three-gradient pore structure pure foamed silicon carbide membrane tube and its preparation method. The three-gradient pore structure composed of foamed silicon carbide support and fine surface film layer, the material composition is pure silicon carbide, there is no binding phase such as oxides, it has high porosity, low pressure drop, high strength, good thermal shock resistance, It has the characteristics of high service temperature and easy back blowing regeneration. It can be used in oxidizing atmosphere or in reducing atmosphere. It has strong acid and alkali corrosion resistance. It can be used in coal gasification chemical industry, IGCC, PFBC coal gasification power generation, high temperature flue gas, Filtration and purification of various high- and low-temperature fluids such as automobile exhaust and water purification; the preparation method includes batching, support molding, film layer preparation and firing in sequence. The process is simple, low-cost, easy to implement, and can guarantee product performance.
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| CN201410696037.2ACN105688684B (en) | 2014-11-27 | 2014-11-27 | With three gradient pore structured pure matter foam silicon carbon supporter membrane tubes and preparation method |
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