Anti-paste Bag Performance of Water-repellent Filter Media in High-humidity Environments Considering Ultra-low Emissions

This study performed surface treatment of Flumex, polyimide, and membrane-covered aramid (chosen as test substrates) by the C8-1833 water-repellent agent. Five key parameters (C8-1833 concentration, impregnation time, rolling residue rate, baking temperature, and baking time) were selected to investigate their effects on the filter media’s water-repellent grade and air permeability variation rate. Through an orthogonal optimization test, the optimal water-repellent process parameters were determined. Air and dust filter media test beds were employed to assess the anti-paste bag performance of water-repellent and membrane-covered filter media under high-humidity conditions. The results indicate that the water-repellent grade of the filter media was unaffected by the baking time during complete drying. At water- repellent agent concentrations of no less than 30 g L-1, impregnation times exceeding 3 s, baking temperatures exceeding 240℃, and rolling residue rates below 46%, both filter materials achieved a water-repellent grade 8. Under optimized processing conditions, the water-repellent grade of the filter media reached 8, and the contact angle was maximized, significantly enhancing the hydrophobicity. Both water-repellent and membrane-covered filter media delayed wet dust adhesion. However, in excessively high humidity of flue gas, sustained filtration performance of the filter media might not be achievable. In bag sticking or rapid condensation situations, the water-repellent filter material should be initially dried using high-temperature flue gas and subsequently restores its filtration performance through thorough dust cleaning.