【作者】 邱燃；

【导师】 刁永发； 顾平道；

【作者基本信息】 东华大学 ， 供热、供燃气、通风及空调工程， 2009， 硕士

【摘要】 由于燃煤电厂排放大量可吸入颗粒物和重金属的高温烟气,针对日益严重的高温烟气污染问题,常规的除尘方法必须经降温冷却处理后,才能够进行除尘净化处理。且烟气在经过降温冷却处理阶段,损失了大量的能量,热利用率较低,耗能巨大,而且对细颗粒的脱除效果不好,不能满足目前日趋严格的环保要求,必须寻找脱除细微飞灰的新方法,研究脱除的新机理。利用多孔陶瓷除去可吸入颗粒物及其重金属等有毒物质的过滤方法愈来愈受到人们的重视。多孔陶瓷由于其具有耐高温、高压、抗酸碱腐蚀性能、热稳定性好、过滤效率高、使用寿命长等特点而得到广泛应用。但是其致命缺点是性脆,强度小,力学性能差。针对此问题,本课题采用陶瓷纤维制品和氧化锆增韧陶瓷基体的多孔陶瓷过滤材料是值得探索研究开发的课题,对高温环境下除尘技术发展和增韧新型复合陶瓷过滤材料的发展具有实用价值和工程指导意义。首先,本课题采用冷态实验法模拟实际工况环境,对叠加和缝制方式下不同厚度的陶瓷纤维制品进行了过滤性能测试,得到在洁净状态下的陶瓷纤维制品过滤阻力与过滤风速近似呈一次方线性变化规律,并根据试验数据得到拟合曲线;通过对陶瓷纤维制品过滤效率的测试,总体满足高温除尘技术的要求,但是部分过滤效果不是很好,测得个别实验值计算为负,分析其原因是由于陶瓷纤维制品内部含有结晶微粒和微细纤维,故在使用前需要进行预处理。其次,利用陶瓷纤维制品增强方法和氧化锆的相变增韧机理,采用注浆覆膜涂抹法,通过不同的试样配比、试验工艺和烧成制度制得陶瓷纤维制品和氧化锆增韧氧化铝、氧化硅和高岭土陶瓷基体的高温除尘用复合型多孔陶瓷过滤材料试样。再次,对氧化硅、氧化铝、氧化锆和高岭土4种陶瓷粉料进行基本性能测试,得到其平均粒径,化学含量和粒径分布;通过对陶瓷烧结坯体的TG、DTA、DTG和DSC等综合热分析测试,得到试样受热变化的各种热分析数据,为确定烧成制度提供了依据;通过对烧结体的XRD测试,得到4种陶瓷粉料的化学组成和物相分布,测试得到部分试样中发生了氧化锆的马氏体相变,即氧化锆相变增韧陶瓷基体的变化;通过对烧结体的SEM显微形貌观察,分析所制得的复合型陶瓷过滤材料具有丰富的气孔,但在高温烧结过程中部分陶瓷粉料和过量粘结剂熔融成液相填充了骨料之间孔隙,应当避免堵塞已形成的气孔;通过对烧结体吸水率、气孔率和体积密度的测试,得到烧结体试样体积密度较小,范围为1.0094～1.8255g/cm~3;烧结体试样的吸水率范围主要为20～60%,试样气孔率范围主要为30%～70%;通过对烧结体强度的测试发现,抗弯强度达到3.5MPa,抗压强度达到16MPa,随着烧结时间的延长,抗弯强度有所增加,抗压强度显著提高:通过对试样烘干和烧结的线变化率测试,总体表现为长度、宽度方向收缩和厚度方向膨胀;通过对烧结坯体烧结后表观密度测试,得到表观密度范围在0.34～0.84g/cm~3;随着烧成温度的升高和保温时间的延长,试样的气孔率呈逐渐下降的趋势。随着高温粘结剂加入量的增加,陶瓷烧结体的强度缓慢增加,气孔损失增大,气孔率减少。最后,采用冷态实验法对复合型陶瓷过滤材料进行了过滤性能测试,得到在在洁净状态下的复合型陶瓷过滤板的过滤阻力与过滤风速呈二次方变化规律,并根据试验数据得到拟合曲线,相关性很好,基本符合多孔陶瓷过滤理论要求;通过对陶瓷过滤板的过滤效率的测试,过滤效率在30%～40%,虽然过滤效果不是最优,但是需要进一步提高和改善。本课题在制备复合型陶瓷过滤材料的基础上有其创新和改进措施,具有一定的研究意义、有很好的开发价值和广泛的应用前景。更多还原

【Abstract】 Due to lots of inhaled particles and heavy metals in the high temperature gas dusts were emitted form coal fired power generetion plants,it became increasingly serious air pollution of hightemperature gas dusts.it must be reduced them temperature and coolling treated,then these high temperature gas dusts could be dust-removalled and cleanned.At this moment,heat was lost,heat-utilizing was low,energy consuming was huge,and dust cleaning effect was bad,the routine methods of dust removal were not satisfacted with the rigorous standard environmental protection.Used porous ceramics to clean inhaled particles and heavy metals toxicants of new filtering ways had quite recognized.It took on excellent high temperature and high pressure resistance,good acid and alkali eorrosion resistance,high filtration efficiency and long service life.But its fetal weakness were lowly intensity,badly brittleness.Aimed at this issue,the paper was put forward to rein-forced porous ceramic relying on ceremic fiber rein-forced and zirconia transformation toughening mechanisms.The resultant theory and method are given to design and optimize the ceramic filter element.Firstly,This subject was used cold-simulation testing method to the actual environmental conditions,the filtration resistance and the filtration velocity was accorded with the linear law,and got the fitting curve.The filtering efficiency of the ceramic fiber products was also tested,The effect was not very good,some of the experimental data was negative,The reason that was the ceramic fiber products containing crystalline particles and microfibers.Secondly,using ceramic fiber products and the zirconia transformation toughening mechanism,with grouting film method,The’ratio of different samples and testing and firing process of ceramic fiber products.The zirconia toughened alumina,silica and kaolin ceramic matrix of porous ceramic filter material sample were created And silica,alumina,zirconia and kaolin four basic ceremic power materials were tested them performance,including the average sizes,size distributions and chemical contents.The thermal analysis of sintering bodies were studied by TG,DTA,DTG and DSC.In order to determine the sintered body,the XRD of four ceramic powders were applied,some samples taken place the zirconia martensitic transformation,which was the transformation toughening zirconia ceramic matrix changes.microstructure were analyzed and observed by SEM.But in the process of sintering,ceramic powders and some liquid phase filled and blocked among the aggregate pores,water absorption, density,porosity were also tested,density was 1.0094-1.8255g/cm~3;water absorp tion was 20-60%,Mainly sample porosity was 30%-70%,bending strength was 3.5MPa, compressive strength was 16 MPa.The sintering strength with the sintering time,the slow increase in bending strength and compressive strength to increase significantly.By drying the sample and rate of change sintering line test for the performance of the overall direction of the width of the length of the shrinkage and the thickness direction of expansion.By sintering body after apparent density test,the apparent density was 0.34～0.84g/cm~3,whicf was meeted the high-porous ceramic filter results.With the sintering temperature and holding time of the extension,the porosity of the sample showed a gradual downward trend,ceramic sintered slow increase in strength,porosity loss increased to reduce the porosity.Finally,the composite ceramic filter materials were tested by colding-state,filters pressure and wind speeds was accorded with the quadratic law,ceramic filter through the filter efficiency of the board of the test.Filtration efficiency of 30%-40%,although the effect of filtering is not optimal,yet to some extent to the strength of materials and mechanical properties improved.Preparation of the porous ceramic filter had its innovations and improvements,the study has some significance great economical value in heat utilization and extensive applications foreground.更多还原