高浓度粉尘过滤组件的构建及其过滤特性

Construction and property of air filter for high dust concentration

为了解决在煤矿高浓度粉尘环境下,传统防尘面罩用滤膜孔隙率小、容尘量低、呼吸阻力随使用时间快速增加等问题,提出了一种兼具高容尘量和及时清灰功能的多级过滤组件。该组件一级过滤采用轻质的聚苯乙烯(PS)发泡颗粒层,二级精滤采用纳米纤维滤膜。在自建的实验平台上对多级过滤组件的空载过滤特性、动态加载过滤特性、清灰性能以及过滤参数进行了研究。研究结果表明:在过滤风速为0.15 m/s时,泡沫层的过滤阻力为17.8 Pa,是纯纤维滤料的18%,多级过滤组件的过滤阻力略微小于各级单独过滤阻力之和。在初始加载过程中,多级过滤组件过滤阻力的增加速率仅为纯纤维滤料的54.3%,说明泡沫颗粒层的加入明显地提高了过滤组件的容尘量;在风速为0.6 m/s的反吹风清灰后,其过滤阻力增加速率进一步降为纯纤维滤料的28.5%,实现了PS泡沫颗粒层的及时清灰功能。扫描电镜显示,在纯纤维滤膜中,滤膜中存在粒径为6.12μm的粉尘,对滤膜造成了严重堵塞;而多级过滤组件中,纤维滤膜中只存在粒径最大为2.57μm的粉尘。当PS泡沫颗粒层的厚度为2 cm时,其过滤效率能达到84.2%;随着过滤风速的增加,泡沫颗粒层的过滤效率逐渐降低。

In order to solve the problems of low porosity,low dust capacity and rapid increase of breathing resistance with time,a novel multi-stage filtration assembly with the properties of high dust capacity and in-time cleaning was proposed.The novel filtration assembly consists two components.The first coarse competent is made of a foamed polystyrene(PS)granular bed and the high efficiency competent is made of a fiber membrane.The performances such as empty filtering,dynamic loading c,ash clearing and filtering parameters of proposed filtering assembly were investigated on the self-built experimental platform.The results showed that when the airflow was 0.15 m/s,the empty filtration resistance was 17.8 Pa,which is 18%of the pure fiber filter material,and the filter resistance of the multi-stage filtration component is slightly less than the total of individual filter resistance.In the initial loading process,the increase rate of the filtration resistance of the proposed air filter was only 54.3%of that of the pure fiber filter,what means the addition of foam particle bed can significantly increase the dust capacity of the filtration component.When the filtration components was ash cleaned by air velocity of 0.6 m/s,the increase rate of filtration resistance was further reduced to 28.5%of that of the pure fiber filter,which means the timely ash-cleaning function of PS foam particle bed is realized.The SEM pictures showed that in the pure fiber membrane,there were many particles with size of 6.12 m in the membrane void,which causes the serious blockage.While in the multi-stage filter assembly,only dusts smaller than 2.57 m were present in the fiber filter membrane.When the thickness of PS foam particle layer is 2 cm,its filtration efficiency can reach 84.2%.The filtration efficiency of foam particle layer is reduced with the increase of filter velocity.