Coal PDF

COAL 1  INTRODUCTION India is the second largest producer of coal in COAL the world (997.83 MT: 2023-24 FY) Coal reserves around (April, 2023, pib.gov.in) 199.9 Billion tonnes (P1) – Measured...

COAL 1  INTRODUCTION India is the second largest producer of coal in COAL the world (997.83 MT: 2023-24 FY) Coal reserves around (April, 2023, pib.gov.in) 199.9 Billion tonnes (P1) – Measured 151.68 Billion tonnes (P2) – Indicated 26.62 Billion tonnes (P3) - Inferred About 71% (Dec. , 2023) of electricity is generated by coal in India  Coal is and will continue to be the “Power Fuel” of the Indian Power Sector in the foreseeable future  Coal-based power plants grows by 10% between 2021-22 and 2022-23 2 Source: Ministry of Coal, 2023  INTRODUCTION (Contd..) Coal: Inhomogeneous organic fuel formed mainly from decomposed plant matter Coalification 3 INTRODUCTION 4 Liptinites - are dark gray - hydrogen-rich hydrocarbons derived from spores, pollens, cuticles, and resins in the original plant Vitrinites -are medium to light gray- "gelified" wood, bark, and roots, and contain less hydrogen than liptinites Inertinites -are white and can be very bright- mainly oxidation products of other macerals and are consequently richer in carbon than liptinites or vitrinites 5  INTRODUCTION (Contd..) RAW COAL Mineral matrix Carbonaceous infrastructure Volatile matter Moisture Above depend strongly on: coal age, source, packing conditions 6  COAL CLASSIFICATION - BASIS 1. By Type refers to kind of plant material, mineral inclusions, nature of maturation 2. By Rank refers to degree of metamorphosis 3. By Grade refers to amount and kind of inorganic material within coal matrix 7  COAL CLASSIFICATION BY TYPE I. U.S. Bureau of Mines System 1. Banded Coals – visible bands of vitrain, Fusain larger fragments of ancient plant 2. Non-banded Coals – Uniform texture II. International System 1. Humic (banded) Coals 2. Liptobiolithic (non-banded) coals 8  COAL CLASSIFICATION BY RANK Coal % carbon content Anthracite 68-98 Bituminous 45-86 Sub -bituminous 35-45 Lignite 25-35 Source: World Coal Institute 9  COAL CLASSIFICATION BY GRADE S.No. Grade UHV in MJ/kg 1 Grade A >26 2 Grade B 23-26 3 Grade C 21-23 4 Grade D 17.5-21 5 Grade E 14-17.5 6 Grade F 10-14 7 Grade G 5.5-10 UHV: Useful Heat Value = 8900 - 138(A+M) kcal/kg A: Ash M: Moisture (in weight percentage) 1 kcal = 4.186 kJ 10 Source: Ministry of Coal  COAL - PROPERTIES Physical Mechanical Thermal Electrical Density Strength Calorific Value Electrical resistivity Specific gravity Hardness Heat Capacity Dielectric Pore structure Friability Thermal constant Conductivity Surface area Grindability Plastic/ Reflectivity Dustiness Index Agglomerating Index Colour Free Swelling Index Ash Characteristics 11  COAL – CHEMICAL ANALYSIS Proximate Analysis* India USA (typical) (typical) 1 Fixed carbon ~24% ~48.8% 2 Volatile matter ~21% ~33.6% 3 Total moisture ~12% ~8.8% 4 Mineral matter (Ash) ~43% ~8.8% (low grade) Ultimate Analysis* 5 Carbon 34.8% 64.7% 6 Hydrogen 2.4% 4.6 % 7 Oxygen (difference) 6.6% 8.5 % 8 Nitrogen 0.7% 1.2 % 9 Sulfur 0.5% 3.4 % (high quality) 10 Gross Calorific Value (MJ/kg) 15.5 27 GCV: Natural Gas: ~ 53 MJ/kg Diesel : ~ 45 MJ/kg *Source: NTPC & DOE 12  COAL USE  Thermal coal (about 90% use): Used mainly in power stations to produce high pressure steam, which then drives turbines to generate electricity Also used to fire cement and lime kilns Until the middle of the 20th Century used in steam engines  Metallurgical coal: Used as a source of carbon, for converting a metal ore to metal Removing the oxygen in the ore by forcing it to combine with the carbon in the coal to form CO2  Coking coal: Specific type of metallurgical coal Used for making iron in blast furnaces 13