【作者】 杜柳柳；

【导师】 沈恒根；

【作者基本信息】 东华大学 ， 供热、供燃气、通风与空调工程， 2008， 硕士

【摘要】 由于燃煤过程、垃圾焚烧等产生的高温烟气中含有大量的腐蚀性成分,严重影响袋式除尘器的滤料使用寿命。PTFE纤维具有耐腐蚀、耐高温的特点,利用国产化PTFE纤维制成PTFE滤料及其复合滤料是值得研究开发的课题,对促进袋式除尘技术发展和应用具有实用价值和工程指导意义。本课题采用冷态实验法模拟工况环境,对涂层处理的100%PTFE针刺毡、未涂层处理的100%PTFE针刺毡、覆膜处理的PTFE纤维+玻纤复合梯度滤料和化学剂处理的PTFE纤维+玻纤复合滤料、PPS针刺毡进行耐温、耐腐蚀性能试验,检测其断裂强力、断裂伸长率的变化。通过试验得到:采用复合滤料、后处理工艺能显著加强滤料的耐腐蚀性能;提出改进滤料耐腐蚀试验方法的建议,供完善滤料检测技术参考。以微细颗粒物为主要控制对象,设计滤料分级过滤性能测试的试验装置。测试不同过滤方式滤料(HST梯度滤料、常规针刺毡、FMS针刺毡及P/G覆膜滤料)在清洁及集尘状态下的过滤分级效率。结果表明:滤料过滤分级效率与粒径尺度成正比变化关系,且集尘状态下的分级效率明显高于清洁状态。总体上,滤料过滤分级效率由高到低为:覆膜滤料、梯度复合针刺毡、复合针刺毡、常规针刺毡。同时,设计优化试验装置以测试滤料在疲劳强度及动态条件下的过滤性能。采用医用滑石粉做试验粉尘对各种滤料进行清洁、集尘状态下的阻力性能试验测试和分析,得到:清洁滤料压力损失与过滤速度成正比一次方关系;集尘后压力损失与过滤时间、粉尘负荷分别呈正比二次方变化关系。结合滤料集尘试验,推导出滤料清灰周期的计算式。结合袋式除尘工程实际问题,给出滤料选用方案并计算得出其清灰周期。针对袋式除尘器过滤含尘气体浓度问题,提出了清灰周期修正系数K,强调袋式除尘设计中进气气流组织、清灰模式对设备性能影响的重要性。更多还原

【Abstract】 The flue gas of different industrial sector, such as coal-fired boiler and waste incineration, contains large amounts of corrosive gas with high temperature, which has seriously affected the performance and the life of filtration medium of bag filter. The research on the application of PTFE needle felt and PTFE compound filtration medium made of domestic PTFE fiber is worthy of being studied as PTFE fiber has the properties of corrosion resistance and thermal resistance, thus will definitely promote the development and application of bag filter technology and bring significant economic & social benefits and help to optimize the project.In order to evaluate the thermal resistance and corrosion resistance of different filtration medium with different fiber and after treatments, the tensile strength and tensile elongation of five filtration medium: coated 100% PTFE needle felt, uncoated 100% PTFE needle felt, composite gradient filter medium of PTFE fiber+fiberglass felt with PTFE membrane and chemical treatment and PPS needle felt were tested, which immersed in H₂SO₄ or NaOH with different concentration in the lab to simulate the application environment. The tests showed that filtration medium with different fibers and after treatment obviously could enhance the strength of filter media. Meanwhile, some suggestions were given for optimizing the the testing technology of filtration medium.To control the discharge of major pollutants, especially of the fine particulate matter, a testing device for grade efficiceny of filtration medium was designed. Filtration medium with different type （HST gradient filter, conventional needle felt, FMS needle felt and P/G membrane filtration medium） in cleaning and dust collection were tested. The results showed that grade efficiency was diverse with particle size, and the efficiency in dust collection was significantly higher than that in cleaning state. Overall, grade efficiency of different filtration medium from high to low was: membrane media, compound gradient filter, compound needle felt and conventional needle felt. Optimized testing device was also given to test the efficiency of fitration medium in fatigue state and its dynamic performance.Based on the testing and research on different filtration medium with dust collection which using medical dust as the testing dust, a mathematical method was used to visualize the changes of pressure drop, which showed that pressure drop was linearly proportional to filtering velocity in cleaning state and turned to be quadratic correlation with dust cake. Thus the cleaning cycle time of different filtration mediun in flat state was calculated which could help ensure the dust cleaning interval under an actual case.Combined the experimental research with an actual case, new type filtration medium was developed and its cleaning cycle was calculated. Meanwhile, the correction coefficient K would still need be further studied to modify cycle time concerning the the changeable dust concentration, which emphasizesed the design of bag filter should be pay great attention as inlet airflow and cleaning mode had great importance on the performance of equipment.更多还原