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Show Table 7 Slagging and Fouling Indices 3 i Teat 1. Ash Fusion Temperature Index Values Fuels 2. T, 3. T1S, 4. X Basic Constituent 7* 5. Base-to-Acid Ratio (B/A) 6. Ra - Slagging Factor 7. Rf, Rf' - Fouling Factor Initial Deformation (I.D.) Softening, S.T. (Sph.) Softening, S.T. (Hemp.) Fluid (F.T.) Temperature at which viscosity changes from Newtonian to Bingham plastic Temperature at 250 poiee £X(Fe,0, • CaO • MgO • Na40 • K,0) lZ(Fej0, + CaO * MgO * Na,0 + K,0) E2(Alt0, • SiO, • TiO,) (B/A)(Z S on dry coal) Rf = (B/A)|Z Na,0 (ASTM ash)] Rf" • (B/A)[Z water soluble Na,0 from LTA (low temperature ash)) Function of ash chemistry S.T. used to select furnace exit Temperature None Rat ings (Dry Bottom) Low Medium High Severe None TV Rat ings (Wet Bottom) >2325 2550 to 2100 2275 to 2050 <2200 T,, <2600"F 0.5 maximum for dry bottom units >0.27 for wet bottom units la. <0.6 0.6-2.0 2.0-2.6 >2.6 Slagging Type Low Medium High Severe vs Rf' <0.2 0.2-0.5 0.5-1.0 >l.O <0.1 0.1-0.25 0.25-0.7 >0.7 Fouling Type Low Medium High All All All All All Eastern coals only Eastern coals only 8. Sodium Content of Coal Ash X Na,0 in ASTM ash Lignitic Bituminous X N a ^ Fouling X Na,0 Fouling <2.0 2-6 6-8 8 Low Medium High Severe <0.5 0.5-1.0 1.0-2.5 >2.5 Low Medium High Severe All 9. Alkali Content of Coal Ash l(X Na,0 • 0.6589)(Z K,0) Same as 4 All |