压力对纳米纤维复合滤材过滤性能的影响

Influence of pressure on filtration performance of nanofiber composite filtering material

天然气输送过程中,需采用净化手段分离其中的液体杂质,但目前净化用聚结滤芯的过滤性能尚有待提高。为此,采用复合纳米纤维的方式研发新型过滤材料,利用滤材实验装置在0.1~0.5 MPa压力范围内对4种复合滤材的渗透性能及气液过滤性能进行测试。结果表明:复合滤材的达西系数均随纳米纤维面密度增大而降低,其中高渗透性基材复合纳米纤维后,其达西系数下降幅度更为明显;操作压力升高将导致滤材结构出现压缩,使得达西系数与非达西系数的相互关系发生改变;在复合纳米纤维后,滤材过滤效率得到提高,但压降也相应增大,在纳米纤维面密度相同时,疏油型滤材压降变化较亲油型滤材更为显著,面密度过大将造成压降过高,导致滤材综合性能降低。研究成果可为天然气净化用滤材的选型提供参考。

Purification technology is required to separate the liquid impurities of natural gas during its transportation.However,the filtration performance of coalescing filter element used for natural gas purification at present needs to be improved.Therefore,the new filtering materials were developed by a nanofiber composite method.Besides,the permeability and gasliquid filtration performance of the 4 types of composite filtering materials were tested with the experimental devices under the pressures from 0.1 MPa to 0.5 MPa.The results show that the Darcy coefficient of the composite filtering materials decreases with the increasing of the surface density of nanofiber,and more significant decrease is observed after the substrate with high permeability is composited with the nanofiber.Meanwhile,the increasing of operating pressure can lead to the compression of filtering material structure,which further results in the change of the mutual relationship between the Darcy coefficient and non-Darcy coefficient.Moreover,the filtration efficiency of filtering materials is improved after compositing with nanofiber,but the pressure drop also increases.Under the condition of same surface density of nanofiber,the pressure drop in oleophobic filtering material is more significant than the oleophilic filtering material.Hence,too high surface density will result in excessive pressure drop,further causing the reduction of the comprehensive performance of filtering materials.Generally,the research results could provide reference for the selection of filtering materials for natural gas purification.