Improving filtration and pulse-jet cleaning performance of metal web filter media by coating with polytetrafluoroethylene microporous membrane

摘要

The metal web filter media has been widely used to purify high-temperature exhaust gas because of its good durability and reliability. Although it has fine high-temperature resistance, its filtration efficiency for fine particles is relatively low. In this study, we developed a new type of composite filter of metal web coated with polytetrafluoroethylene (PTFE) membrane, which combined the high-temperature resistance of the metal web filter and the excellent filtration performance of the membrane-coated filter media. The performance parameters of the composite filter, including pressure drop, filtration efficiency, regeneration efficiency, adhesive force, and high-temperature resistance, were investigated experimentally, and compared with those of the metal web filter and polyester fiber coated with PTFE membrane filter. Although the composite filter yielded a higher pressure drop, it exhibited a high particle collection efficiency. At a face velocity of 10.23 cm/s, the filtration efficiency of the composite filter was 99.32 %. This was 1.23 and 0.10 % higher than that of the metal web filter and polyester coated with PTFE membrane filter, respectively. In addition, the composite filter has the characteristics of small cake/fabric adhesion force, low residual pressure drop, high regeneration efficiency, and long cleaning interval. The average cleaning interval and residual pressure drop of the composite filter were 421 s and 425.0 Pa, respectively, whereas those of the metal web filter were 291 s and 658.5 Pa, respectively; those of the polyester coated with PTFE membrane filter were 415 s and 443.2 Pa, respectively. Furthermore, the filtration test at high temperatures and thermogravimetric analysis demonstrated that the composite filter has an excellent thermal stability. At a temperature of 260 degrees C, the average dust emission concentration of the polyester coated with PTFE membrane filter was 2.86 times larger than that of the composite filter (0.532 mg/m(3)). (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.