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May 2, 2015 Central Fuel Research Institute Dhanbad 828 108 presents by Kalyan Sen and Rahul Das Gupta Beneficiation of difficult-to-wash Low Volatile Coals of Jharia and Bokaro Coalfields
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May 2, 2015 Coal in India Total Coal Reserve 206 billion tonnes Distribution Non Coking (Gondowana) 83 % Coking (Gondowana) 14 % Others 3 %
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May 2, 2015 Coking Coal Scenario
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May 2, 2015 Characteristics of LVCC p High raw coal ash37-40% p Low volatile matter content15-16% p Poor washability potential p High MaturityRo = 1.3 p High Reserve15,680 mt
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May 2, 2015 Mining Condition f LVC coals outcrop near the fringe areas of coalfields f Easy for Opencast production f Low overburden : coal ratio (upto 3) f Low slope (1 : 15) f Possibility of high scale mechanization
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May 2, 2015 Washability Potential \ Very poor washability due to typical geological formation \ Liberation of coal / mineral particles by progressive size reduction is insignificant
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May 2, 2015 Mayer’s Curve
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May 2, 2015 Present scenario Annual Production of LVCC (16 -18 mt) n 8 to 10 mt from Jharia n 6 to 8 mt from East Bokaro Use of NLW coals l Power Stations (major consumption) l Beehive ovens (minor consumption)
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May 2, 2015 Beneficiation in existing washeries Existing Washeries p 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 p 3-product circuit p 4-product circuit
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May 2, 2015 Beneficiation in existing washeries Existing Washeries p 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 ?
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May 2, 2015 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
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May 2, 2015 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
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May 2, 2015 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
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May 2, 2015 Washed Coal Coke Property Porosity %48.5 CRI12.6 CSR72.9 M 40 82.6 M 10 9.8
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May 2, 2015 Proposed Scheme 4-Product Washing Multi Stage Concept 1st Stage 3-product Jig 2nd Stage HM & Flotation
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May 2, 2015 1st Stage Products w Rejects 28-30% wt, 60-65% ash w Middlings 20-22% wt, <34% ash w Pre-cleans (about 50%), 22-24% ash
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May 2, 2015 2nd Stage Product w Cleans 25-30% wt, 18% ash w Foundry cleans 20-25% wt, 28% ash Cost of cleans = about 3 times that of Raw coal
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May 2, 2015 Multi-stage Concept
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May 2, 2015 Comparative Cost of Cleans 2-product5 3-product4 4-product3
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May 2, 2015 Thank You
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