The document discusses fabric filter technology as an alternative to electrostatic precipitators for reducing emissions from coal-fired power plants. It provides details on the operating principles of fabric filters, components of fabric filter plants, and opportunities for localizing fabric filter bag manufacturing and installation in South Africa. Eskom is planning to replace electrostatic precipitators with more efficient fabric filter plants and seeks industry input on strategies for local manufacturing of filter bags.

1. 31 March 2011 Bongi Cindi SD & L – Filter Bag Presentation

5. Filter Types and Filter Cleaning Methods 1. Reverse air cleaning 2. Pulse-jet cleaning 3. Shake/deflate systems Source: Soud, 1995

6. The Thermal Power Fabric Filter Plant Components

8. Fabric Filter Plant OPEX Components Fibre Material Bag filters made of fabric fibre materials, textile, plastics and ceramics Factors determining process quality are removal efficiency Surface morphology of new fiber at 3,000x magnification Surface morphology of new fiber at 7,500x magnification Surface morphology of used fiber at 3,000x magnification Surface morphology of used fiber at 7,500x magnification

9. Fabric Filter Plant OPEX Components……… contd Fibre Material Typical fabrics used for bags Sources: McKenna and Turner 1989 and Greiner 1993. 2.5-4.0 good excellent excellent 232 450 191 375 Ryton® Polymer 2.0 very good very good fair 218 425 204 400 Nomex® Aromatic polyamide 6.7 fair excellent except poor for trifluoride, chlorine, and molten alkaline metals excellent except poor for fluorine 260 500 232 450 Teflon® Fluorocarbon 1.0 poor to fair poor good 288 550 260 500 Fiberglas® or glass Glass 0.6 excellent excellent poor to fair 121 250 93 200 Nylon Polyamide 2.5 fair fair good 260 500 232 450 P84® Polymer Surges Continuous 0.5 excellent fair good 163 325 135 275 Dacron® Polyester 0.7 average fair very good 127 260 116 240 Orlon® Acrylic 0.8 average poor good 121 250 93 200 Wool Natural fiber protein 0.5 0.4 Relative cost excellent excellent Alkali Resistance 93 107 °C 88 82 °C Polypropylene Cotton Fiber good excellent 200 190 Polyolefin average poor 225 180 Natural fiber cellulose °F °F Flex abration resistance Acid Resistance Maximum temperature Generic Name

11. Fabric Filter Plant OPEX Components ……… contd Bag Manufacturing process Welding of filter cage Filter cage Filter Bag Final Product Bag stitching

12. Related Industries in South Africa Filters are used in many other SA industries to aggregate volumes for industrialisation of filter bags Pharmaceuticals Food industry Woodworking Sinter plants Metal working Foundries Textiles Chemical industry Coal-fired boilers Asphalt batch plants Municipal waste incinerators Cement kilns Lime kilns Electric steel furnaces Gypsum calcining Ore smelters and roasters Sintering plants Rock dryers Foundries Carbon black Magnesium oxide kilns Coal-fired boilers Screening, crushing, and conveying of rock products Low temperature steel applications Metal working Mining operations Textiles Woodworking processes Chemical industry Food industry Coal-fired boilers Pulse-jet Reverse-air Shaker Typical industrial applications for baghouses

13. Way Forward Eskom is looking at Industry to provide input into the fabric filter bag (FFB) strategy, especially on the process around manufacturing of the bags

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