Basics8-CoalCharacteristics-Oct08.pdf
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The document from the Indiana Center for Coal Technology Research discusses various characteristics and classifications of coal, including its formation, types (anthracite, bituminous, sub-bituminous, and lignite), and physical and chemical properties. It details the coal composition, ranks, volatile matter, sulfur content, heating values, and the impact of coal quality on energy generation. Additionally, the document provides insights into coal analysis and its applications, such as in power generation and coke production.
![CCTR
Indiana Center for Coal Technology Research
7
COAL COMPONENTS
Volatile matter consists of aliphatic carbon atoms (linked in open
chains) or aromatic hydrocarbons (one or more six-carbon rings
characteristic of benzene series) and mineral matter
Ash consists of inorganic matter from the earth’s crust:- limestone,
iron, aluminum, clay, silica, and trace elements (concentrations of
less than 1000 ppm [<0.1% of a rock’s composition] of zinc, copper,
boron, lead, arsenic, cadmium, chromium, selenium)](https://image.slidesharecdn.com/basics8-coalcharacteristics-oct08-220610111832-fb9945bb/85/Basics8-CoalCharacteristics-Oct08-pdf-7-320.jpg)
Basics8-CoalCharacteristics-Oct08.pdf
- 1. CCTR Indiana Center for Coal Technology Research 1 Brian H. Bowen, Marty W. Irwin The Energy Center at Discovery Park Purdue University CCTR, Potter Center, 500 Central Drive West Lafayette, IN 47907-2022 http://www.purdue.edu/dp/energy/CCTR/ Email: cctr@ecn.purdue.edu October 2008 COAL CHARACTERISTICS CCTR Basic Facts File # 8 Indiana Center for Coal Technology Research
- 2. CCTR Indiana Center for Coal Technology Research 2 As geological processes apply pressure to peat over time, it is transformed successively into different types of coal Source: Kentucky Geological Survey http://images.google.com/imgres?imgurl=http://www.uky.edu/KGS/coal/images/peatcoal.gif&imgrefurl=http://www.uky.edu/KGS/coal/coalform.htm&h=354&w=579&sz= 20&hl=en&start=5&um=1&tbnid=NavOy9_5HD07pM:&tbnh=82&tbnw=134&prev=/images%3Fq%3Dcoal%2Bphotos%26svnum%3D10%26um%3D1%26hl%3Den%26sa%3DX COAL FORMATION
- 3. CCTR Indiana Center for Coal Technology Research 3 COAL ANALYSIS Elemental analysis of coal gives empirical formulas such as: C137H97O9NS for Bituminous Coal C240H90O4NS for high-grade Anthracite Coal is divided into 4 ranks: (1) Anthracite (2) Bituminous (3) Sub-bituminous (4) Lignite Source: http://cc.msnscache.com/cache.aspx?q=4929705428518&lang=en-US&mkt=en-US&FORM=CVRE8
- 4. CCTR Indiana Center for Coal Technology Research 4 BITUMINOUS COAL http://images.google.com/imgres?imgurl=http://www.mii.org/Minerals/Minpics1/CoalBituminous.jpg&imgrefurl=http://www.mii.org/Minerals/photocoal.html&h=308&w=360&sz= 38&hl=en&start=1&um=1&tbnid=ZKBL7apLynZMcM:&tbnh=104&tbnw=121&prev=/images%3Fq%3Dcoal%2Bphotos%26svnum%3D10%26um%3D1%26hl%3Den%26sa %3DX Bituminous Coal: Great pressure results in the creation of bituminous, or “soft” coal. This is the type most commonly used for electric power generation in the U.S. It has a higher heating value than either lignite or sub-bituminous, but less than that of anthracite. Bituminous coal is mined chiefly in the Midwest & Appalachia
- 5. CCTR Indiana Center for Coal Technology Research 5 ANTHRACITE COAL Anthracite: Sometimes also called “hard coal,” anthracite forms from bituminous coal when great pressures developed in folded rock strata during the creation of mountain ranges. This occurs only in limited geographic areas – primarily the Appalachian region of Pennsylvania. Anthracite has the highest energy content of all coals & is used for making coke, a fuel used in steel foundry ovens http://images.google.com/imgres?imgurl=http://www.mii.org/Minerals/Minpics1/CoalBituminous.jpg&imgrefurl=http://www.mii.org/Minerals/photocoal.html&h=308&w=360&sz= 38&hl=en&start=1&um=1&tbnid=ZKBL7apLynZMcM:&tbnh=104&tbnw=121&prev=/images%3Fq%3Dcoal%2Bphotos%26svnum%3D10%26um%3D1%26hl%3Den%26sa %3DX
- 6. CCTR Indiana Center for Coal Technology Research 6 COAL RANK Anthracite coal is a dense, hard rock with a jet- black color & metallic luster. It contains between 86% and 98% carbon by weight, & it burns slowly, with a pale blue flame & very little smoke Bituminous coal (in Indiana), contains between 69% & 86% carbon by weight Sub-bituminous coal contains less carbon, more water & is a less efficient source of heat Lignite coal, or brown coal, is a very soft coal that contains up to 70% water by weight. Emits more pollution than other coals Source: http://cc.msnscache.com/cache.aspx?q=4929705428518&lang=en-US&mkt=en-US&FORM=CVRE8
- 7. CCTR Indiana Center for Coal Technology Research 7 COAL COMPONENTS Volatile matter consists of aliphatic carbon atoms (linked in open chains) or aromatic hydrocarbons (one or more six-carbon rings characteristic of benzene series) and mineral matter Ash consists of inorganic matter from the earth’s crust:- limestone, iron, aluminum, clay, silica, and trace elements (concentrations of less than 1000 ppm [<0.1% of a rock’s composition] of zinc, copper, boron, lead, arsenic, cadmium, chromium, selenium)
- 8. CCTR Indiana Center for Coal Technology Research 8 Each type of coal has a certain set of physical parameters which are mostly controlled by (a) moisture (b) volatile content (aliphatic or aromatic hydrocarbons) & (c) carbon content COAL PHYSICAL PARAMETERS • Aliphatic - designating a group of organic chemical compounds (carbon compounds) in which the carbon atoms are linked in open chains • Hydrocarbons - numerous organic compounds, such as benzene & methane, that contain only carbon & hydrogen • Aromatic - containing one or more six-carbon rings characteristic of the benzene series
- 9. CCTR Indiana Center for Coal Technology Research 9 CARBON IN COAL Carbon forms more than 50% by weight & more than 70% by volume of coal (this includes inherent moisture). This is dependent on coal rank, with higher rank coals containing less hydrogen, oxygen & nitrogen, until 95% purity of carbon is achieved at Anthracite rank & above Graphite formed from coal is the end-product of the thermal & diagenetic conversion (process of chemical & physical change in deposited sediment during its conversion to rock) of plant matter (50% by volume of water) into pure carbon
- 10. CCTR Indiana Center for Coal Technology Research 10 COAL VOLATILE MATTER Volatile matter is material that is driven off when coal is heated to 950°C (1,742°F) in the absence of air under specified conditions - components of coal, except for moisture, which is liberated usually as a mixture of short & long chain hydrocarbons, aromatic hydrocarbons & some sulphur - measured practically by determining the loss of weight Consists of a mixture of gases, low-boiling-point organic compounds that condense into oils upon cooling, & tars. Volatile matter decreases as rank increases http://www.britannica.com/eb/article-81704/coal-utilization
- 11. CCTR Indiana Center for Coal Technology Research 11 COAL VOLATILE MATTER http://www.engineeringtoolbox.com/classification-coal-d_164.html
- 12. CCTR Indiana Center for Coal Technology Research 12 SULFUR IN COAL Although coal is primarily a mixture of carbon (black) & hydrogen (red) atoms, sulfur atoms (yellow) are also trapped in coal, primarily in two forms. In one form, (1) the sulfur is a separate particle often linked with iron (green, pyritic sulfur) with no connection to the carbon atoms, as in the center of the drawing (fools gold). In the second form, (2) sulfur is chemically bound to the carbon atoms (organic sulfur), such as in the upper left Source: http:www.fossil.energy.gov/education/energylessons/coal/coal_cct2.html
- 13. CCTR Indiana Center for Coal Technology Research 13 COAL TYPICAL CONTENT % weight Anthracite Bituminous Sub- Bituminous Lignite Heat Content (Btu/lb) 13,000-15,000 11,000-15,000 8,500-13,000 4,000-8,300 Moisture < 15% 2 - 15% 10 - 45% 30 - 60% Fixed Carbon 85 - 98% 45 - 85% 35 - 45% 25 - 35% Ash 10 - 20% 3 - 12% ≤ 10% 10 - 50% Sulfur 0.6 - 0.8% 0.7 – 4.0% < 2% 0.4 – 1.0% Chlorine (ppm) 340 ± 40ppm 340 ± ppm 120 ± 20ppm 120 ± 20ppm
- 14. CCTR Indiana Center for Coal Technology Research 14 COAL TYPES Geologists also classify coal types according to the organic debris, called macerals, from which the coal is formed. Macerals (microscopic organic constituents found in coal) are identified (microscopically) by reflected light - the reflective or translucent properties of the coal indicating the individual component macerals & the way they have combined to form the coal The purpose of classifying coal in this way is to determine its best uses. Mineral content is assessed by burning coal & measuring the amount of incombustible material remaining, referred to as the ash content of coal
- 15. CCTR Indiana Center for Coal Technology Research 15 COAL RANK The degree of 'metamorphism' or coalification undergone by a coal, as it matures from peat to anthracite, has an important bearing on its physical and chemical properties, & is referred to as the 'rank' of the coal http://www.australiancoal.com.au/classification.htm#types Low Rank Coal High Rank Coal Moisture Content HIGH HIGH Carbon/Energy Content Volatile matter, H2 , O2 , N
- 16. CCTR Indiana Center for Coal Technology Research 16 COAL PARAMETER VARIATIONS WITH RANK Source: American Iron and Steel Institute, http://www.steel.org/learning/howmade/coal.htm Moisture content is determined by heating an air-dried coal sample at 105°–110° C (221°–230° F) under specified conditions until a constant weight is obtained Generally the moisture content increases with decreasing rank & ranges from 1 to 40% Increasing Rank Volatile matter is material that is driven off when coal is heated to 950° C (1,742° F) in the absence of air under specified conditions. It is measured practically by determining the loss of weight
- 17. CCTR Indiana Center for Coal Technology Research 17 COAL PARAMETER VARIATIONS WITH RANK Source: American Iron and Steel Institute, http://www.steel.org/learning/howmade/coal.htm Increasing Rank The fixed carbon content of the coal is the carbon found in the material which is left after volatile materials are driven off. This differs from the ultimate carbon content of the coal because some carbon is lost in hydrocarbons with the volatiles Calorific value, measured in Btu is the amount of chemical energy stored in a coal that is released as thermal energy upon combustion. It is directly related to rank Vitrinite is a type of maceral. Vitrinite reflectance can be used as an indicator of maturity in hydrocarbon source rocks INDIANA
- 18. CCTR Indiana Center for Coal Technology Research 18 COAL SIZES COARSE COAL >25.0mm (≈1 inch) SMALL COAL 25.0-3.0mm FINE COAL < 3.00mm (0.12 inch) ULTRA FINE COAL < 0.15mm (0.006 inch)
- 19. CCTR Indiana Center for Coal Technology Research 19 HEATING VALUE (Btu/lb dry) OF THE INDIANA DANVILLE COAL Source: M. Mastalerz, A Drobniak, J. Rupp and N. Shaffer, “Assessment of the Quality of Indiana coal for Integrated Gasification Combined Cycle Performance (IGCC)’, Indiana Geological Survey, Indiana University, June 2005 The heating value shows the amount of energy that is in the coal & is the most important coal parameter for economic benefits & highest engineering efficiencies Higher heat value in Knox County than in Posey. Indiana & Midwest coals have high energy values Sullivan Knox Gibson Posey Higher heat value in Knox County than in Posey County
- 20. CCTR Indiana Center for Coal Technology Research 20 Source: M. Mastalerz, A Drobniak, J. Rupp and N. Shaffer, “Assessment of the Quality of Indiana coal for Integrated Gasification Combined Cycle Performance (IGCC)’, Indiana Geological Survey, Indiana University, June 2005 SULFUR VALUE OF THE INDIANA SPRINGFIELD COAL Knox Sullivan Gibson Posey Sulfur content in Gibson County, for Springfield coal, varies from 0.5% to 4.0%
- 21. CCTR Indiana Center for Coal Technology Research 21 ASH YIELD (Weight %, dry) OF THE INDIANA SPRINGFIELD COAL Source: M. Mastalerz, A. Drobniak, J. Rupp and N. Shaffer, “Assessment of the Quality of Indiana coal for Integrated Gasification Combined Cycle Performance (IGCC)’, Indiana Geological Survey, Indiana University, June 2005 Midwest coals have ash yields of 3.3% to 11.7% & average values for Indiana are about 9.4% Knox Sullivan Gibson Warrick
- 22. CCTR Indiana Center for Coal Technology Research 22 INDIANA & POWDER RIVER BASIN COAL Indiana coal PRB coal Moisture 10 -12% ~ 28% Volatile matter ~ 40% higher Heating value 11,386 Btu/lb Btu/lb 8,088 Ash content 9.4% 7.6% AFT (flow, Reduction) Need more data ? Slag viscosity ~1400oC Need more data ? Char reactivity Very few data Less reactive (higher T needed?) More reactive because of more volatiles? Sulfur 3.13% 0.72% Chlorine 0.05% 0.01% Source: M. Mastalerz, A. Drobniak, J. Rupp and N. Shaffer, “Assessment of the Quality of Indiana coal for Integrated Gasification Combined Cycle Performance (IGCC)’, Indiana Geological Survey, Indiana University, June 2005
- 23. CCTR Indiana Center for Coal Technology Research 23 INDIANA COAL BED CHARACTERISTICS Source: M. Mastalerz, A. Drobniak, J. Rupp and N. Shaffer, Indiana Geological Survey, Indiana University, 2008
- 24. CCTR Indiana Center for Coal Technology Research 24 EFFECT OF COAL QUALITY ON HEAT RATE & CAPITAL COST Source: “Economic Analysis of New Coal Fired Generation Options”, George S. Booras et al, EPRI, Palo Alto, 2004 Indiana Coal PC & IGCC power plants PC = Pulverized Coal, IGCC = Integrated Gasification Combined Cycle
- 25. CCTR Indiana Center for Coal Technology Research 25 PURDUE WADE PLANT % % Btu/lb Btu/lb % lbs Moisture Ash As Rec As Rec Dry basis Sulfur As Rec Sulfur per MBtu Stoker 15.74 7.96 11,146 13,224 1.02 1.77 CFB 14.73 10.27 10,870 12,733 2.38 4.27 OF UG/G UG/G UG/G Fusion Temp Grind Index Mercury D4208 Chlorine D6721 Chlorine Stoker 2490 57 0.05 204 128 CFB - 59 0.09 121 - CFB = Circulating Fluidized Bed boiler technology - environmentally acceptable technology – burns wide range of solid fuels to generate steam & electricity power ranging from 5 MW to 250 MW Stoker = Stoker Boiler Systems - used on small boilers for over a century. They use a lump coal feed (UG/G = micro grams per gram)
- 26. CCTR Indiana Center for Coal Technology Research 26 PURDUE WADE PLANT Indiana coal is the prime fuel source for the Wade Plant. During fiscal year 2005-06, Wade consumed 48,130 Ton of high-sulfur coal, 118,509 Ton of low-sulfur coal, 10,838 Ton of limestone, and 466,935 Therms of natural gas for an average fossil fuels delivered cost of approximately $2.452/MBtu http://www.purdue.edu/utilityplant/plantoperation.htm Generation Approx 40 MW with 3 generators 29 MW turbine generator 10 MW turbine generator 1.7 MW diesel generator & 9 centrifugal chillers
- 27. CCTR Indiana Center for Coal Technology Research 27 COKE & PETCOKE Coke is a solid carbonaceous residue derived from low-ash, low-sulfur bituminous coal from which the volatile constituents are driven off by baking in an oven without oxygen at temperatures as high as 1,000 °C (1,832 °F) so that the fixed carbon & residual ash are fused together. Coke is used as a fuel & as a reducing agent in smelting iron ore in a blast furnace. Coke from coal is grey, hard, & porous & has a heating value of 24.8 MBtu/ton (29.6 MJ/kg). Byproducts of this conversion of coal to coke include coal tar, ammonia, light oils, and "coal-gas“ Petroleum coke is the solid residue obtained in oil refining, which resembles coke but contains too many impurities to be useful in metallurgical applications http://en.wikipedia.org/wiki/Coal
- 28. CCTR Indiana Center for Coal Technology Research 28 COAL PRODUCTS TREE http://images.google.com/imgres?imgurl=http://pubs.usgs.gov/circ/c1143/html/coal_tree.jpg&imgrefurl=http://pubs.usgs.gov/circ/c1143/html/centerfold.html&h=736&w= 1000&sz=434&hl=en&start=102&um=1&tbnid=AcfQD7qmScAhrM:&tbnh=110&tbnw=149&prev=/images%3Fq%3Dcoal%2Bphotos%26start%3D90%26ndsp%3D18%26 svnum%3D10%26um%3D1%26hl%3Den%26sa%3DN