FoSSIl FUElS Coal COAL. Nazrul Islam Coal Expert & Former Managing Director Infrastructure Investment Facilitation Company (IIFC) Dhaka, Bangladesh

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1 COAL NATURAL GAS OIL Learning about FoSSIl FUElS Coal 85% of the world s commercial energy SAARC Dissemination Workshop Assess the Present Situation, Gaps in Capacity, Technology and Policy & Regulatory Instruments in Coal Sector in SAARC Member States Nazrul Islam Coal Expert & Former Managing Director Infrastructure Investment Facilitation Company (IIFC) Dhaka, Bangladesh November 2017 The Hotel Soaltee Crowne Plaza, Kathmandu, Nepal

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3 Storing the Sun s solar energy at Soaltee Crowne Plaza Hotel on 14 Nov

4 Coal: The Ignoble Fuel 4

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9 The Composition of Coal Main Elements: Carbon Hydrogen Oxygen Nitrogen Sulfur 9

10 Coal what is it? Proximate Analysis Elemental Composition C H O S N Char Ash H 2 O VM 65-95% 2-7% <25% <10% 1-2% 20-70% 5-15% 2-20% 20-45% Inhomogeneous organic fuel formed mainly from decomposed plant matter. Over 1200 coals have been classified. Coalification forms different coal types: (Peat) Lignite Bituminous coal Anthracite (Graphite) Time, Temperature Coal Rank 10

11 Underground (shaft) mine Coal Mining Surface (strip) mine

12 COAL RESERVES IN BANGLADESH Coal Deposits Depth of Deposit (meters) Estimated Reserve (mt) 1 Jamalganj Barapukuria Khalashpir Phulbari Dighipara Total Total Coal Reserves in Bangladesh Is almost 3 billion tonnes

13 COMBUSTION REACTION C + O 2 CO 2 + Heat Almost 99% of C in coal is converted to CO 2. In order to lower CO 2 emission levels, coal power plants will have to leave steam-based systems (37% efficiency) and go towards coal gasification technology (60% efficiency). 13

14 Main Processes in Coal Combustion volatiles homogeneous combustion CO 2, H 2 O, coal particle p-coal, d=30-70 m char heterogeneous combustion CO 2, H 2 O, devolatilization t devolatile =1-5ms t volatiles =50-100ms t char =1-2sec t 14

15 The physical processes influencing pulverized coal combustion Turbulent/swirling flow of air and coal. Turbulent/convective/molecular diffusion of gaseous reactants and products. Convective heat transfer through the gas and between the gas and coal particles. Radiative heat transfer between the gas and coal particles and between the coal/air mixture and the furnace walls. 15

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18 Coal Combustion Air Pollutants CO 2 CO NOx SOx Particulate matter Trace metals Organic compounds 18

19 Particulate Matter Bottom Ash Fly Ash PM composition and emission levels are a complex function of: 1. Coal properties, 2. Boiler firing configuration, 3. Boiler operation, 4. Pollution control equipment. In PC power plants, since combustion is almost complete, the emitted PM is primarily composed of inorganic ash residues. 19

20 Organic Compounds Include volatile, semivolatile and condensable organic compounds either present in the coal or formed as a product of incomplete combustion. Characterized by hydrocarbon class: alkanes, alkenes, aldehydes, alcohols and substituted benzenes. The main groups of environmental concern are: 1) dioxins and furans. 2) Polycyclic organic matter (POM). Emissions dependent on combustion behavior in the boiler (air/fuel ratio, residence time, temperature or turbulence). 20

21 Sulfur in Coal (<10%) Organic sulfur (40%) Chemically bonded to the hydrocarbon matrix in the forms of thiophene, thiopyrone, sulfides Inorganic sulfur (60%) Imbedded in the coal, as loose pyrite - FeS 2 and calcium/iron/barium sulfates. 21

22 SOx reduction Pre combustion removal: Physical cleaning (30-50% removal inorganic sulfur) Chemical and biological cleaning (90% removal organic sulfur) Combustion configuration: No benign sulfur species! gasification combined-cycle systems (IGCC systems) Post-combustion removal: Wet Flue Gas Desulfurization (FGD) (80-98%) In situ sulfur capture: Dry Sorbent Injection (DSI) (50%) 22

23 Nitrogen Oxides (NOx) volatiles Fuel-N HCN/NH 3 HCN/NH 3 + O 2 NO (formation) NO + HCN/NH 3 N 2 (destruction) The major source of NO in coal utility boilers (>80%). 23

24 NO Reduction Combustion controls: 1. Modification of combustion configuration: Reburning Staged Combustion (air/fuel) Post combustion controls: 1. Injection of reduction agents in flue gas. 2. Post-combustion denitrification processes. 24

25 Electricity Generation Sources Coal Natural gas Oil Hydrop ower Renewab le Energy Nuclea r power Access to Electricity kilowatt hours billions % of total % of total % of total % of total % of total % of total % of population South Africa India 1, China 5, South Asia 1, Australia Indonesia Germany World 23, United States 4, United Kingdom Bangladesh World Development Indicators, THE WORLD BANK 25

26 US Energy Policy 26