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TRANSPORTATION OF DRY FLYASH: ISSUES FOR CONSIDERATION

TRANSPORTATION OF DRY FLYASH: ISSUES FOR CONSIDERATION. By V.K.Agarwal Indian Institute of Technology, Delhi. Figure 9 Sketch of Particulate Flow in Dilute Phase Conveying. Mode of Conveying. Dilute Phase - Suspension Flow: Requirements No ne

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TRANSPORTATION OF DRY FLYASH: ISSUES FOR CONSIDERATION

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  1. TRANSPORTATION OF DRY FLYASH: ISSUES FOR CONSIDERATION By V.K.Agarwal Indian Institute of Technology, Delhi

  2. Figure 9 Sketch of Particulate Flow in Dilute Phase Conveying

  3. Mode of Conveying Dilute Phase - Suspension Flow: Requirements None Pick-Up Velocity 12 m/s fine powders (minimum) 16 m/s fine granules for horizontal conveying

  4. Figure 11 Sketch of Particulate Flow in Moving Bed Flow

  5. Mode of Conveying Dilute Phase - Suspension Flow Requirements None Pick-Up Velocity 12 m/s fine powders (minimum) 16 m/s fine granules Dense Phase - Non-Suspension Flow Sliding Bed Flow: Requirements Good Air Retention Pick-Up Velocity 3 m/s (minimum)

  6. Figure 14 Sketch of Particulate Flow in Plug Type Flow

  7. Mode of Conveying Dilute Phase - Suspension Flow Requirements None Pick-Up Velocity 12 m/s fine powders (minimum) 16 m/s fine granules Dense Phase - Non-Suspension Flow Sliding Bed Flow: Requirements Good Air Retention Pick-Up Velocity 3 m/s (minimum) Plug Flow: Requirements Good Permeability Pick-Up Velocity 3 m/s

  8. Solids Loading Ratio (dimensionless) - - (3) where ϕ = solids loading ratio = mass flow rate of material - tonne/h and = mass flow rate of air used - kg/s

  9. Diagram to Illustrate the Wide Range of Conveying Systems Available for Conventional Systems Operating With a Single Air Source

  10. Sketch of Typical Negative Pressure Conveying System

  11. Ash Accumulation Points and Typical Ash Distribution of a Dry Bottom Furnace

  12. Typical Arrangement of Electrostatic Precipitator Ash Collection Hoppers

  13. Pneumatic Ash Removal Systems with Conveying Parameters Indicated

  14. Typical Dry Fly Ash Handling Arrangement at a Power Station

  15. CONVEYINGCAPABILITY • In Terms of • Material Flow Rate • Conveying Distance • Minimum Conveying Air Velocity • Power Requirements • Depends Upon: • Pipeline Bore • Pipeline Length • Pressure Drop Available • Material Properties

  16. Parameters Relating Compressor Rating with Material Flow Rate

  17. Influence of Solids Loading Ratio on Conveying Air Velocity for Fine and Coarse Grades of Flyash

  18. Sketch of Test Facility Pipeline at the IIT Pipeline Details: Bore - 63 mm Length - 133 m Bends - 10

  19. Conveying Characteristics for Fine Grade of Fly Ash with Conveying Line Inlet Air Velocity Data Superimposed

  20. Conveying Characteristics for Coarse Grade of Fly Ash with Conveying Line Inlet Air Velocity Data Superimposed

  21. Solids loading ratio Conveying line inlet air velocity - m/s Conveying line pressure drop - bar 4 6 Conveying limit 8 10 160 120 24 20 16 12 8 4 0 24 20 16 12 8 4 0 80 100 60 50 Conveying line inlet air velocity - m/s NO GO AREA 2·0 NO GO AREA 12 Solids loading ratio 40 1·8 30 Conveying limit 1·6 Fly Ash Flow Rate - tonne/h Fly Ash Flow Rate - tonne/h 14 14 1∙4 Conveying line pressure drop - bar 20 15 16 2·0 18 1·2 1·6 10 20 10 1·2 5 0·8 0·8 0·4 0·4 0 0·04 0·08 0·12 0·16 0 0·04 0·08 0·12 Air Mass Flow Rate - kg/s Air Mass Flow Rate - kg/s a) Coarse fly ash b) Fine fly ash Figure 5 Comparison of Conveying Characteristics for Fine and Coarse Grades of Fly Ash in IIT Pipeline

  22. Reference Point Pressure Drop (bar) Air Flow Rate (kg/s) Inlet Air Velocity (m/s) Solids Loading Ratio Fly Ash Flow Rate (tonne/h) Test Loop Plant Test Loop Plant 1 1.8 0.038 3.7 150 103 20.5 14.1 2 1.3 0.060 7.2 55 40 11.8 8.64 3 1.0 0.090 12.3 20 16 6.6 5.22 4 0.8 0.087 13.2 14 11 4.5 3.59 Conveying Parameters for Design Cases Considered in Relation to 63 mm Bore Line

  23. Pipeline Bore (mm) Fly Ash Flow Rate – (tonne/h) Conveying Line Pressure Drop – (bar) 1.8 1.3 1.0 0.8 150 80 51 33 23 200 144 91 60 41 250 226 144 95 65 300 325 209 138 94 Fly Ashy Flow Rate in Plant Pipeline of Various Bores for Range of Conveying Line Pressure Drops Considered

  24. Sketch of a Typical Vacuum Conveying System Incorporating a Stepped Pipeline for Conveying Different Grades of Fly Ash

  25. Conveying air Velocity Profiles for the Conveying of both Coarse and Fine Ash in a Common Negative Pressure Conveying System

  26. RECOMMENDED OPTIONS FOR COAL ASH HANDLING AND SAFE DISPOSAL

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