, 毛宁, 常德强东北大学 资源与土木工程学院, 辽宁 沈阳 110819
收稿日期：2016-03-08
基金项目：“十二五”国家科技支撑计划项目(2015BAK40B00)；“十三五”国家重大专项(2016YFC0801704)。
作者简介：田新娇(1989-), 女, 山东滨州人, 东北大学博士研究生;
柳静献(1966-), 男, 河北元氏人, 东北大学教授, 博士生导师。
摘要：研发基于超细纤维的滤料是控制PM2.5的主要技术方向之一.采用国家标准建议的实验装置, 对新型超细海岛纤维滤料的过滤性能进行综合研究, 得出了滤料的过滤效率、残余阻力、清灰周期等参数, 并与常规针刺毡滤料和覆膜滤料对比.结果表明:海岛纤维滤料对PM2.5的计数效率为94.9%, 远高于常规针刺毡滤料, 与覆膜滤料相当; 动态过滤过程的残余阻力低于覆膜滤料, 残余阻力上升缓慢, 清灰周期更长, 有利于延长滤料的寿命, 节约成本.
关键词：海岛纤维滤料PM2.5过滤效率清灰周期残余阻力
Experimental Study on the New Filter Made from Sea-Island Fibers
TIAN Xin-jiao, LIU Jing-xian
, MAO Ning, CHANG De-qiangSchool of Resources & Civil Engineering, Northeastern University, Shenyang 110819, China.
Corresponding author: LIU Jing-xian, E-mail: liujingxian@mail.neu.edu.cn
Abstract: Developing superfine fiber filter is one of the main technical methods to control PM2.5. An experimental setup was used according to the national standards, and the filtration performance of sea-island-fiber filters was studied comprehensively.Such parameters as the filter efficiency of filter material, the residual resistance and the ash cleaning cycle were obtained, and a comparison was made with the traditional needle felt filters and membrane filters. The results showed that the counting efficiency of sea-island-fiber filters for PM2.5 is 94.9%, which is far higher than that of the traditional filters and similar to that of the membrane filters; meanwhile, the residual resistance of the dynamic filtration process is lower than that of the membrane filters, the residual resistance increases slowly, and the ash cleaning cycle becomes longer, which is conducive to prolonging the filterlife and saving cost.
Key Words: sea-island fiber filterPM2.5filtration efficiencyash cleaning cycleresidual resistance
随着工业的迅速发展, 环境污染日益严重.袋式除尘器是最有效的控制工业烟尘、抑制雾霾的有效方法[1].理论证明, 纤维越细, 其过滤效率和精度越高, 因此研发基于超细纤维的滤料是控制PM2.5的主要技术方向之一.覆膜滤料捕集细颗粒存在一定优势, 但在实际应用中薄膜容易过早破损.基于超细海岛纤维的滤料, 其纤维细度小, 对微细颗粒的捕集效率高, 是新一代过滤材料.
本文通过对比新型海岛纤维滤料、覆膜滤料和针刺毡滤料, 研究海岛纤维滤料对微细颗粒物的捕集效率和动态过滤性能, 为新滤料的研发提供参考[2-3].
1 海岛纤维滤料海岛纤维是一种超细纤维的制造方法.它是将一种聚合物以极细的形式分散于另一种混合物中, 在纤维截面中分散相呈“岛”状态, 而母体则相当于“海”状态, 一般海岛复合纤维具有常规纤维的纤度, 用溶剂把“海”的成分溶掉后, 就能得到超细海岛纤维束[4-5].
海岛纤维滤料的纤维直径在1 μm左右, 常规滤料的纤维直径在5~20 μm, 海岛纤维的纤维比表面积大, 织物孔隙率高且孔径大小及排列均匀, 使得海岛纤维滤料在捕集细颗粒的精度和效率上显著提高, 密实的海岛纤维迎尘表层还阻止粉尘进入滤料内部, 减少了粉尘在滤料内部的聚集[6-9].
2 实验过程和样品本文以新研发的海岛纤维滤料为对象, 对比常规针刺毡和覆膜滤料, 通过实验研究其性能:
1) 通过静态过滤实验, 研究各滤料样品对0.3, 0.5, 1.0, 3.0, 5.0 μm细颗粒物的计数效率;
2) 通过动态过滤实验, 研究各滤料样品在清洁和老化阶段的清灰周期和压力损失.
2.1 静态过滤过程采用图 1所示实验装置研究各滤料对不同粒径微细粒子的过滤效率.
图 1(Fig. 1)
 | 图 1 滤料过滤效率测试装置Fig.1 Experimental apparatus for filtration efficiency of the filter material |
2.2 动态过滤过程实验采用中位径为6.2 μm的Al2O3粉尘.全尘滤料实验按照GB6719—2009进行, 该标准与德国VDI3926和国际标准相兼容, 实验装置如图 2所示.
图 2(Fig. 2)
 | 图 2 滤料动态过滤性能测试装置Fig.2 Experimental apparatus for dynamic filter performance test |
2.3 实验样品实验样品参数和电镜图片见表 1和图 3.
表 1(Table 1)
 表 1 实验样品参数Table 1 Parameters of experimental samples
| 表 1 实验样品参数 Table 1 Parameters of experimental samples |
图 3(Fig. 3)
 | 图 3 各滤料的扫描电镜图Fig.3 Electron microscope scanning pictures of the filters (a)—针刺毡滤料; (b)—覆膜滤料; (c)—海岛纤维滤料. |
由表 1和图 3可知, 本实验所用的海岛纤维滤料单根纤维的平均直径是针刺毡纤维直径的1/23, 海岛纤维滤料纤维直径最小且纤维的直径尺寸非常稳定.覆膜滤料表面附着一层薄薄的薄膜；针刺毡滤料纤维左右聚集, 相互缠结呈一定厚度和显著的三维形态, 纤维直径大小不均匀.
3 实验结果及分析3.1 分粒径计数效率覆膜滤料、针刺毡滤料和海岛纤维滤料的计数效率见图 4.由图 4可知, 各滤料对特定粒径粒子的过滤效率受风速影响不大; 随着粒径从0.3 μm增大到5 μm, 同种滤料的计数效率增大; 对2.5 μm细粒子的计数效率，覆膜滤料为99.1%, 海岛纤维滤料为94.9%, 针刺毡滤料为65.6%;对3~5 μm的粒子, 覆膜滤料为99.38%, 海岛纤维滤料为99.37%, 针刺毡滤料为72.45%.可以看出海岛纤维滤料的过滤性能接近覆膜滤料.
图 4(Fig. 4)
 | 图 4 不同风速下的计数效率Fig.4 Counting efficiency at different wind speeds (a)—v=1.5 m/min; (b)—v=2.0 m/min; (c)—v=2.5 m/min. |
3.2 动态过滤过程3.2.1 清灰周期图 5为滤料在洁净状态和经过老化后的稳定状态时, 每个清灰周期所用时间与周期序号之间的关系.由图 5可知, 清洁阶段的平均清灰周期:覆膜滤料 > 海岛纤维滤料 > 针刺毡滤料.稳定阶段的平均清灰周期：海岛纤维滤料 > 覆膜滤料 > 针刺毡滤料.海岛纤维滤料在清洁和稳定阶段的清灰周期变化不大, 且在稳定阶段的清灰周期最长, 有利于延长滤料的寿命, 降低能耗和成本.
图 5(Fig. 5)
 | 图 5 滤料30个过滤周期所需时间Fig.5 Required time for 30 filtration cycles (a)—清洁阶段; (b)—稳定阶段. |
3.2.2 各周期残余阻力图 6为滤料在洁净状态和经过老化后的稳定状态时, 其每次喷吹清灰后残余阻力与周期序号之间的关系.
图 6(Fig. 6)
 | 图 6 滤料30个过滤周期的残余阻力Fig.6 Residual resistance of the filters for 30 filtration cycles (a)—清洁阶段；(b)—稳定阶段. |
从图 6可看出，稳定阶段各滤料的平均残余阻力比清洁阶段的平均残余阻力均有一定幅度的上升.清洁状态和老化后稳定阶段各滤料的平均残余阻力的大小:覆膜滤料 > 海岛纤维滤料 > 针刺毡滤料；残余阻力小, 有利于延长滤料寿命、降低能耗和成本.
3.2.3 全尘效率通过动态过滤实验对洁净状态和老化后稳定阶段的滤料的全尘除尘效率进行计算, 结果见表 2.
表 2(Table 2)
表 2 各种滤料的全尘除尘效率Table 2 TSP removal efficiencies of all the filters
| 表 2 各种滤料的全尘除尘效率 Table 2 TSP removal efficiencies of all the filters | |||||||||||||||
由表 2可知, 海岛纤维滤料、覆膜滤料和针刺毡滤料的全尘效率都在99.9%以上, 海岛纤维滤料清洁阶段和稳定阶段的全尘效率高于针刺毡滤料, 老化之后的全尘效率, 海岛纤维滤料与覆膜滤料相同, 为99.999 8%.
4 结论1) 海岛纤维滤料单根纤维的平均直径为1.5 μm, 是针刺毡纤维直径的1/23, 且单根纤维直径尺寸非常稳定.
2) 海岛纤维滤料对微细颗粒有较好的捕集效果, 对2.5 μm颗粒的计数效率在94.9%左右, 接近覆膜滤料的98.9%, 大大高于针刺毡的61.3%, 是控制细颗粒尤其PM2.5的新型滤料.
3) 海岛纤维滤料的全尘效率略低于覆膜滤料, 但高于针刺毡滤料; 经过老化后进入稳定阶段, 海岛纤维滤料的全尘效率与覆膜滤料相当.
4) 海岛纤维滤料属于近表层过滤方式, 残余阻力比覆膜滤料小, 稳定阶段的清灰周期比覆膜滤料长, 有利于延长滤料寿命、降低能耗和成本.
5) 海岛纤维滤料的性能优于针刺毡, 与覆膜滤料接近，且更加牢固，其应用会越来越广.
参考文献
| [1] | Chen C C, Yu W, Huang S H, et al. Experimental study on the loading characteristics of needle felt filters with micrometer-sized monodisperse aerosols[J].Aerosol Science and Technology, 2001, 34(3): 262–273.DOI:10.1080/02786820120458 |
| [2] | Jing L X, Sun S, Wang X. The research of splitting craft for air filter with sea-island superfine fiber needled fabrics[J].Applied Mechanics and Materials, 2013, 35(4): 2567–2571. |
| [3] | Li Y J, Chang W. Pore structure and liquid behavior of nonwovens composed of nanosized fibers by conjugate spinning[J].Journal of Applied Polymer Science, 2012, 126(25): 252–259. |
| [4] | Kamiyama M, Soeda T, Nagajima S. Development and application of high strength polyester nanofibers[J].Journal of Applied Polymer Science, 2012, 20(6): 987–994. |
| [5] | Zhang X Q, Jin G L, Ma W J. Fabrication and properties of poly(L-lactide) nanofibers via blend sea-island melt spinning[J].Journal of Applied Polymer Science, 2015, 11(3): 342–349. |
| [6] | Sugawara K, Ikaga T, Kim K H. Fiber structure development in PS/PET sea-island conjugated fiber during continuous laser drawing polymer[J].Journal of Applied Polymer Science, 2015, 19(8): 37–46. |
| [7] | Tsai C J, Tsai M L, Lu H C. Effect of filtration velocity and filtration pressure drop on the bag-cleaning performance of a pulse-jet bag house[J].Separation Science and Technology, 2002, 35: 211–226. |
| [8] | Carlos M, Romo K. A qualitative study of atmospheric aerosols and particles deposited on flat membrane surfaces by microscopy and other techniques[J].Powder Technology, 2006, 161(37): 235–241. |
| [9] | Wei Q F, Xiao X L, Hou D Y, et al. Characterization of nonwoven material functionalized by sputter coating of copper[J].Surface & Coatings Technology, 2008, 202(5): 2535–2539. |
