Fabric Filter Technology for Utility Coal-Fired Power Plants

Abstract

Performance of Full-Scale Utility Baghouses This is the third in a series of papers discussing the experience of electric utilities in applying baghouse technology for the collection of particulate matter at coal-fired electric power generating plants. The series presents new data obtained in research sponsored by the Electric Power Research Institute (EPRI) on reverse-gas and shake/deflate cleaned baghouses, and specifically addresses a number of unresolved issues in the design and operation of these units. This paper provides an overview of the design and operating characteristics of baghouses now in place in the utility industry. In addition, it discusses three key issues in design and operation: the relationships among dust cake weight and chemical composition, air-to-cloth ratio, and pressure drop; fabric selection; and bag life.

Improving Baghouse Performance at the Monticello Generating Station

“…10 When these samples were compared with an SEM to similarly prepared bag samples from other baghouses, it was clear that the Monticello fly ash had so completely filled the fabric interstices that few flow channels remained. 4 Several general conclusions can be drawn from these results:…”

“…4 In particular, it has a much higher calcium content than the fly ash from a typical lowsulfur, western, subbituminous coal. Tests carried out on fly ash removed from the interior and exterior of one of the Monticello bags showed no difference in particle size or chemistry.…”

“…Microscopic examination of Monticello fly ash with a scanning electron microscope (SEM) shows that it is quite smooth and more free of submicron agglomerates on the surface of larger fly ash particles than the ash from a typical low-sulfur, western, subbituminous coal. 4 The noncohesive nature of the Monticello ash could in part be related to its microscopically smooth surface. Or, it is possible that its unusually high negative charge (as an aerosol) helps inhibit the agglomeration of submicron fly ash particles onto larger, micron-sized particles.…”

“…Compared to measurements made on samples from every other utility baghouse tested as part of the EPRI study, the highest resistance to flow was recorded for the Monticello samples. 4 A thick coating of ash is usually found on every exposed surface in any Monticello baghouse compartment, with ash deposits on the tube sheets ranging from 2 to 8 in. Also, the outside of a typical bag is coated with an ash layer, usually about % in.…”

Survey on the Use of Pulse-Jet Fabric Filters

“…Pulse-jet cleaning is complicated by the need for air compressors, compressed-air piping, air-drying systems, manifold systems, a venturi or blowtube above each bag, metal support cages inside bags, and other complex equipment, which may create concerns about maintenance and dependability. 7 Problems in changing out bags due to cage-handling difficulty can effectively limit bag length. The bags and cage assemblies are not collapsible, so 92 JAPCA the longer the assembly, the more difficult it becomes to change bags without dislodging the dust cake.…”