Filter bag sdl presentation v3


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  • Filter bag sdl presentation v3

    1. 1. 31 March 2011 Bongi Cindi SD & L – Filter Bag Presentation
    2. 2. Contents <ul><li>Filter Principle of Operation </li></ul><ul><li>Advantages and Disadvantages Over ESP’s </li></ul><ul><li>Filter Types and Filter Cleaning Methods </li></ul><ul><li>The Thermal Power Fabric Filter Plant Components </li></ul><ul><li>Fabric Filter Plant CAPEX Components </li></ul><ul><li>Fabric Filter Plant OPEX Components </li></ul><ul><li>Related Industries in South Africa </li></ul><ul><li>Way Forward </li></ul>
    3. 3. Filter Principle of Operation <ul><li>Gases (and also liquids) are separated from dispersed particles by passing it through a fabric “medium” with a large surface area </li></ul><ul><li>Particles that are not able to penetrate the medium will be retained on its surface, forming the so-called “filter cake” </li></ul><ul><li>The filter cake is equally important to the actual filtration process as the medium. </li></ul>Source: Klingspor and Vernon, 1988
    4. 4. <ul><li>Advantages </li></ul><ul><li>Filter systems are the main alternative for Electro Static Precipitators (ESP’s) systems </li></ul><ul><li>Offer very high collection efficiencies of typically above 99%, over rather large size ranges </li></ul><ul><li>Performs well in high electric resistivity ashes </li></ul>Advantages and Disadvantages Over ESP’s <ul><li>Disadvantages </li></ul><ul><li>Larger pressure drop </li></ul><ul><li>The low allowable gas velocity making them larger than ESP plants </li></ul><ul><li>High capital expenditure than ESP’s </li></ul><ul><li>Eskom Position </li></ul><ul><li>Currently Eskom power stations has mix of ESP’s & fabric filter plants (FFP’s) </li></ul><ul><li>Based on the effectiveness of the filter bag technology to reduce emissions, Eskom is planning to embark on fleet to replace all ESP’s with FFP’s </li></ul><ul><li>There are immediate capex opportunities to localise on the fabrication and installation of FFP’s </li></ul><ul><li>There are opex opportunities for industrialisation of the filter bag fibre </li></ul>
    5. 5. Filter Types and Filter Cleaning Methods 1. Reverse air cleaning 2. Pulse-jet cleaning 3. Shake/deflate systems Source: Soud, 1995
    6. 6. The Thermal Power Fabric Filter Plant Components
    7. 7. Source: Hitachi Fabric Filter Plant CAPEX Components <ul><li>Design </li></ul><ul><li>Civil </li></ul><ul><li>Foundations </li></ul><ul><li>Columns </li></ul><ul><li>Structural Steel </li></ul><ul><li>Mechanical </li></ul><ul><li>Bags, Fabric & Support </li></ul><ul><li>Housing & cladding </li></ul><ul><li>Collection hoppers </li></ul><ul><li>Discharge devices </li></ul><ul><li>Filter cleaning device </li></ul><ul><li>Fans & ducting </li></ul><ul><li>Electrical </li></ul><ul><li>Motors </li></ul><ul><li>Cables </li></ul><ul><li>C&I </li></ul><ul><li>Switchgear </li></ul>Opportunities To maximise local content on fabrication and installation
    8. 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. 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
    10. 10. Fabric Filter Plant OPEX Components ……… contd <ul><li>Fabric Manufacturing process </li></ul><ul><li>Woven fabrics:- filters are made of yarn with a definite repeated pattern </li></ul><ul><li>Felted fabrics:- filters are composed of randomly placed fibers compressed into a mat and attached to loosely woven backing material </li></ul><ul><li>Membrane filter :- is a special treatment where a thin, porous membrane (expanded polyfluorocarbon) is bonded to the scrim, or support fabric. </li></ul>Opportunities All needling of fabric to be localised Source: freepatentsonline. Cross-section of filter at 25x magnification
    11. 11. Fabric Filter Plant OPEX Components ……… contd Bag Manufacturing process Welding of filter cage Filter cage Filter Bag Final Product Bag stitching
    12. 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. 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
    14. 14. END