Influence of oleophobic modification on gas-liquid filtration performance of glass fiber coalescing elements

doi:10.11949/0438-1157.20200689

Abstract

Abstract:

Gas-liquid coalescing elements are widely used in industrial fields such as compressed gas purification. Currently, the performance of coalescing elements is difficult to meet the growing needs of the industry. However, while increasing the filtration efficiency of the coalescing element, the resistance will increase simultaneously, which is not conducive to the optimization of the comprehensive performance. To develop low-resistance high-efficiency coalescing elements, the coalescing filter materials are modified by different concentrations of fluorosilicone acrylate solution. The evolution of pressure drop, filtration efficiency and secondary entrainment of the filter materials with different surface energy during the gas-liquid filtration process were analyzed, the modified filter materials were fabricated into coalescing filters for verification. The results showed that, the filtration efficiency of the modified filter materials was increased by approximately 10%, and the steady-state pressure drop was reduced by approximately 30%. The decrease in jump pressure drop caused by changes in the surface properties of the filter materials is the main cause of the decrease in steady-state pressure drop. The increase in filtration efficiency is caused by the enhancement of diffusion and inertial separation, and the reduction of secondary entrainment. For oleophobic filter materials with different surface energy, the pressure drop and filtration efficiency increase with the decrease of surface energy. The quality factor of the coalescing filter element can be increased by up to 92% after modification.

Key words: oleophobic, surface, filtration, separation, coalescing elements

摘要：

气液聚结元件在压缩气体净化等工业领域应用广泛，目前聚结元件的性能难以满足行业不断增长的需求，但是提高聚结元件过滤效率的同时，阻力也会随之升高，不利于其综合性能的优化。为研制低阻高效的聚结元件，利用不同浓度氟硅氧烷丙烯酸酯溶液对聚结滤材进行疏油改性，分析了表面能不同的滤材在气液过滤过程中压降、过滤效率以及二次夹带现象的变化，并对改性在聚结滤芯上的应用效果进行研究。结果表明，改性滤材在过滤效率提高10%的同时，稳态压降可降低约30%。滤材表面性质变化导致的跳跃压降减小是稳态压降降低的主要原因；滤材内液体分布对扩散、惯性分离作用的增强以及二次夹带的减少是效率提高的主要原因。对于表面能不同的疏油滤材，稳态压降和效率均随表面能的减小而升高。聚结滤芯经过改性后品质因子最大可提高92%。

关键词: 疏油, 表面, 过滤, 分离, 聚结元件

CLC Number:

TQ 028.2

LIU Yufeng,JI Zhongli,CHEN Feng,LIU Zhen,CHANG Cheng. Influence of oleophobic modification on gas-liquid filtration performance of glass fiber coalescing elements[J]. CIESC Journal, 2020, 71(12): 5644-5654.

刘宇峰,姬忠礼,陈锋,刘震,常程. 疏油改性对玻纤聚结元件气液过滤性能的影响[J]. 化工学报, 2020, 71(12): 5644-5654.

Figures/Tables 17

Table 1 Properties of experimental filter materials

滤材	处理剂溶液浓度/%（质量）	平均水接触角/(°)	平均DEHS接触角/(°)	平均孔径/μm	平均纤维直径/μm	初始压降/kPa
GF	—	120.34	39.89	10.61	2.54	0.305
GF1	2	149.35	121.40	10.96	2.86	0.310
GF2	3	148.69	118.73	10.76	2.58	0.309
GF3	4	146.18	114.92	10.92	3.28	0.312
GF4	5	143.84	113.32	11.03	2.79	0.320
GF5	7.5	146.58	116.10	10.87	2.94	0.317
GF6	10	149.05	120.86	11.35	2.82	0.328

Fig.1 SEM micrographs of filter material structure

Fig.2 EDS elemental analysis of filter materials

Fig.3 Filtration performance experimental set-up

Table 2 Parameters of measuring equipment

仪器	型号	量程	精度
扫描电迁移率粒径谱仪	TSI 3936	0.05~0.5 μm	±4%
空气动力学粒径谱仪	TSI 3321	0.5~20 μm	±4%
差压变送器	EJX-110A	0~20 kPa	±0.04%
质量流量控制器	MCR 500 slpm	0~500 slpm	±0.4%
电子分析天平	AL204-IC	0~220 g	0.1 mg

Fig.4 Contact angle of the material to water and DEHS

Fig.5 Comparison of pressure drop for filter materials

Fig.6 Pressure drop division and downstream particle concentration for filter materials

Fig.7 Comparison of saturation for filter materials

Fig.8 Droplets morphology in capillary composed of filter materials pores

Fig.9 Comparison of filtration efficiency for filter materials

Fig.10 SEM micrographs of filter materials after experiments

Fig.11 Comparison of quality factor for filter materials

Fig.12 Comparison of process pressure drop for filters

Table 3 Comparison of pressure drop for filters

滤芯	初始压降/kPa	通道压降/kPa	跳跃压降/kPa	润湿压降/kPa	稳态压降/kPa
F4	1.023	2.194	2.972	5.166	6.189
FN4	1.016	1.821	2.755	4.576	5.592
F6	1.385	2.44	2.907	5.347	6.732
FN6	1.418	2.886	2.102	4.988	6.406
F8	1.828	2.877	2.889	5.766	7.594
FN8	1.873	4.125	2.441	6.566	8.439

Fig.13 Comparison of filtration efficiency for filters

Fig.14 Comparison of quality factor for filters

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