Multi-Scale Polyimide/Carbon Fibers Hybrid Filters for Hot Gas Filtration

Abstract

Increasing air pollution caused mainly by exhaust emission has become a serious concern for public health. In order to efficiently control the exhaust emission from the origin, hot gas filtration is required in many industries, such as thermal power regeneration, metal refining/recycling, and biomass/coal gasification. This study aimed to develop a hybrid filter composed with ultrafine fibrous polyimide (PI) filtration layers and carbon woven fabric supporting layers for hot gas filtration. Uniform PI ultrafine fibers around 200 nm with small pores about 2.2 μm were electrospun on carbon fabrics supporting layers to serve as the filtration layer. During filtration test, NaCl aerosols (0.3 mm), which mimicked PM 2.5 particles were accumulated on the top of filtration layer and formed dust cake, but limited aerosols were observed on the carbon fabric supporting layers. It was proved that PI fiber mats played the key role in filtration. The filtration efficiency could be maintained above 95% after 9 min and reached 99.4 %. This research proved that the multi-scale polyimide/carbon fibers hybrid filters possessed the potential to serve as filtration media in bag filters for hot gas filtration.