ABSTRACT
Filtration is the oldest and usually the most reliable method for removing dusts, fumes, and mists from gases. Filters afford high collection efficiencies with moderate power consumption except for very fine particles or hygroscopic materials. There are three basic types of industrial gas filters: woven or felted fabrics in the form of bags, envelopes, or sleeves; panel filters consisting of semirigid fibrous mats supported within frames; and bulk granular material packed in a column. The performance of a filter is characterized by its pressure loss, collection efficiency, and the service life of both the fabric and ancillary components. Several factors enter into cost comparisons among the various types of particulate control devices, including wet scrubbers and electrostatic precipitators as well as fibrous and fabric filters. Gas-handling capacity, pressure loss, collection efficiency, and durability or service life are the performance characteristics of primary concern for industrial gas filtration.
