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Central Fuel Research Institute Dhanbad 828 108 presents

Central Fuel Research Institute Dhanbad 828 108 presents. Beneficiation of difficult-to-wash Low Volatile Coals of Jharia and Bokaro Coalfields. by. Kalyan Sen and Rahul Das Gupta. Coal in India. Total Coal Reserve 206 billion tonnes. Distribution. Non Coking (Gondowana) 83 %

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Central Fuel Research Institute Dhanbad 828 108 presents

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  1. Central Fuel Research Institute Dhanbad 828 108presents Beneficiation of difficult-to-wash Low Volatile Coals of Jharia and Bokaro Coalfields by Kalyan Sen and Rahul Das Gupta

  2. Coal in India Total Coal Reserve 206 billion tonnes Distribution • Non Coking (Gondowana) 83 % • Coking (Gondowana) 14 % • Others 3 %

  3. Coking Coal Scenario

  4. Characteristics of LVCC • High raw coal ash 37-40% • Low volatile matter content 15-16% • Poor washability potential • High Maturity Ro = 1.3 • High Reserve 15,680 mt

  5. Mining Condition • LVC coals outcrop near the fringe areas of coalfields • Easy for Opencast production • Low overburden : coal ratio (upto 3) • Low slope (1 : 15) • Possibility of high scale mechanization

  6. Washability Potential • Very poor washability due to typical geological formation • Liberation of coal / mineral particles by progressive size reduction is insignificant

  7. Mayer’s Curve

  8. Present scenario • Annual Production of LVCC (16 -18 mt) • 8 to 10 mt from Jharia • 6 to 8 mt from East Bokaro • Use of NLW coals • Power Stations (major consumption) • Beehive ovens (minor consumption)

  9. Beneficiation in existing washeries Existing Washeries • 2-product circuit • About 70-75% with 40-45% ash with no market outlet • Cost of cleans is more than 5 times that of raw coal • 3-product circuit • 4-product circuit

  10. Beneficiation in existing washeries Existing Washeries • 3-product circuit • Low reject disposal capacity of old deshaling Jigs • LVCC requires about 20% disposal • Congenial defects in the cyclones circuits • 60% middlings with 45% ash (Fate ?) • 20% rejects - 50% with 41% ash (outlet ?) • Cost of cleans is 4 times that of raw coal ?

  11. Pilot Scale Study at CFRI 1200t of V-VI-VII-VIII seam coal was beneficiated in the Pilot Plant Cleans at 17-18% ash was carbonized at CFRI & RDCIS Tested at Bokaro test ovens Highly encouraging results

  12. Washed Coal Analysis Petrographic Analysis Mean Ro % 1.27 Vitrinite % 53.2 Semi Vitrinite % 4.8 Exinite % 0.3 Inertinite % 31.5 Mineral Matter % 10.2

  13. Washed Coal Analysis Chemical Analysis Moisture % 0.9 Ash % 18.3 V. M. (%dmf) 21.0 S.I. 5.0 Max Fl. (ddpm) 150.0

  14. Washed Coal Coke Property Porosity % 48.5 CRI 12.6 CSR 72.9 M40 82.6 M10 9.8

  15. Proposed Scheme • 4-Product Washing • Multi Stage Concept • 1st Stage 3-product Jig • 2nd Stage HM & Flotation

  16. 1st Stage Products • Rejects 28-30% wt, 60-65% ash • Middlings 20-22% wt, <34% ash • Pre-cleans (about 50%), 22-24% ash

  17. 2nd Stage Product • Cleans 25-30% wt, 18% ash • Foundry cleans 20-25% wt, 28% ash • Cost of cleans = about 3 times that of Raw coal

  18. Multi-stage Concept

  19. Comparative Cost of Cleans 2-product 5 3-product 4 4-product 3

  20. Thank You

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