【作者】 韩峰； 魏巍； 张峰； 仲兆祥； 邢卫红；

【Author】 HAN Feng;WEI Wei;ZHANG Feng;ZHONG Zhaoxiang;XING Weihong;National Engineering Research Center for Special Separation Membrane,Membrane Science and Technology Insititute,Nanjing Technology University;

【机构】 国家特种分离膜工程技术研究中心南京工业大学膜科学技术研究所；

【摘要】 目前,我国火力电厂、炼钢、冶金等行业耗用大量的煤炭,由于燃烧不完全,其排放的高温气体中富含有大量的微纳尺度颗粒物,在大气中的停留时间长,对大气环境和人体健康的影响很大,对工业窑炉所排放出来高温废气的除尘治理是我国重要的一项环保指标.高温气体过滤处于一个高温、高压及腐蚀性气体环境中,要求过滤元件具有优良的物理化学稳定性能和较高的过滤精度,而传统的袋式除尘技术目前面临不能在高温(>300℃)下运行,使用寿命低,对PM 2.5不能有效截留等诸多问题.在无机陶瓷材料中,碳化硅多孔陶瓷由于在高温(>500℃)下具有优良的抗热震、抗腐蚀性和抗蠕变性、机械强度高等特点,被看做具有广泛应用前景的高温过滤材料之一.以大颗粒碳化硅(200μm)为骨料,采用冷等静压法制备陶瓷管生坯,原位反应烧结制备SiC多孔陶瓷撑体.主要对支撑体的气体渗透性能、抗热震性能、耐高温性能、耐腐蚀性能等进行研究.材料表征结果表明(见图1):制备的碳化硅多孔陶瓷管孔隙率高于40%,抗折强度大于18 MPa,支撑体孔径47μm,当过滤压力为1 kPa时,碳化硅管支撑体的纯气渗透通量达到180 m~3/(m~2·h).在碳化硅多孔陶瓷的应用性能考察中(图2):陶瓷在30~800℃下连续空冷循环60次,抗折强度仍然高于15 MPa;制备的碳化硅陶瓷展现优异的高温抗氧化性能,耐热温度达到1 200℃时;通过对陶瓷腐蚀性能的研究发现:碳化硅陶瓷在80℃的酸和碱中腐蚀100 h,质量损失率小于1%.此外,在陶瓷管表面喷涂一层SiC膜层,膜层孔径2.3μm,对0.3μm的粉尘去除率达到99.95%以上.可以看出制备的碳化硅多孔陶瓷膜在高温过滤领域有很好的应用前景.更多还原

【Abstract】 Currently,a large number of coals were consumed in fire power plants,steel and metallurgy industries etc.They discharged massive hot gas which containingnumeroussub micro scale particlessuspended in the air due to incomplete combustion.These fine particles have a great impact on atmospheric environment and human health.So,the dust concentration is an important environmental indicator for hot gas dischargingfrom industrial furnaces.Because of the high temperature,high pressure and corrosive environmentin hot gas filtration,the filter materials must have aexcellent physical and chemical stability,high filtration precision.However,the bag dust collection technologycan not work in high temperature(>300 ℃) due to self properties.So,the new filter materials are needed urgently.To date,silicon carbide porous ceramics are regardedas excellent materials for hot gasfiltration because of itshigh temperature resistance,excellent thermal shock andcorrosion resistance at hightemperature.In this work,silicon carbide porous ceramics were fabricated by cold isostatic pressuremethod and insitu reaction bonding technology.The thermal shock resistance,high temperature resistance and corrosive resistance were investigated.The characterization of supports showed the open porosity,bending strength and mean pore size were 40%,>18 MPa,47 μm,respectively(in Fig.1b).When the filter pressure was 1 kPa,the gas flow rate could reach 180 m~3/(m~2· h)(Fig.1c).In application performance(in Fig.2),the bending strength was more than 15 MPa after 60 air coolingcycles at 30—800 ℃(Fig.2a).The ceramics kept stability and showed good oxidation resistanceeven at 1 200 ℃(Fig.2b).In corrosive tests,the mass loss ratewasless than 1%in acid and alkali at 80 ℃ for about 100 h(Fig.2c).Furthermore,a layer of SiCmembraneswere coated on the surface of the ceramic tubes.The pore size of the membrane was2.3 μm and the dust removal rate of 0.3 μm reached more than 99.95%(Fig.2d).In short,the silicon carbide porous ceramicshave a potential practicability for use in hot gas filter processes.更多还原