COAL COMBUSTION AND FUELS

Transcription

1 COAL

2 CARBON AND COAL Carbon is a chemical element. Coal is a solid fossil fuel Carbon can exists in a certain allotropic forms including : a) diamond b) graphite

3 RESOURCES OF CARBON IN NATURE a) freely in small amounts (graphite, diamond) b) mainly connected in numerous chemical compounds: - carbonates (CaCO 3, MgCO 3 and in others), - carbon dioxide in air (CO 2 ), - in organic compounds, fossil fuels: natural gas, crude oil, coal and biomass.

4 ORIGIN OF COAL The origin of coal is organic Lignite: cross section through xylite

5 NATURE OF COAL Coal is described as an organic sediment It is a combustible rock: biolite The major chemical elements in coal are: carbon, hydrogen and oxygen.

6 COAL FORMATION The process of coal formation from organic compounds includes two distinct phases: biochemical and geochemical: plant material peat lignite biochemical phase lignite bituminous coal anthracite Geochemical phase

7 HISTORY OF COAL Type of coal Age (years) Bituminous coal mln Brown coal Lignite Peat before100 mln before 70-2 mln from 2 mln to now

8 STRUCTURES OF COAL

9 COAL PETROGRAPHY Petrography is a science about the rocks. The goal of coal petrography: understand how coal was constituted implement of most productive use of coal

10 PETROGRAPHIC STRUCTURES OF COAL Lithotypes (observed with the unaided eye): vitrain, clarain, durain and fusain (bright, halfbright, dull and black (gray-black) and porous and friable) Microlithotypes (observable with the microscope) Macerals: vitrinite group, exinite group, inertinite group.

11 Podział makroskopowy Podział mikroskopowy Skały Litotypy Mikrolitotypy Grupa macerałów Macerały Submacerały Odmiany macerałów Kryptomacerały Witryn (węgiel błyszczący) Klaryn (węgiel półbłyszczący) Witryt V Klaryt V+E Witrynetryt V+I Trimaceryt V+I+E Witrynit V Telinit Kolinit Witrodetrynit Telenit 1 Telenit 2 Telokolinit Żelokolinit Desmokolinit Korpokolinit Kordaitotelinit Fungotelinit Ksylotelinit Lepidofitotelinit Sigillariotelinit Kryptotelinit Kryptokorpokolinit Węgiel Liptyt E Duryn (węgiel matowy) Fuzyn (węgiel włóknisty) Inertyt I DurytI+E Semifuzyt Fuzyt Egzynit (Liptynit) E (L) Sporynit Kutynit Rezynit Alginit Liptodetrynit Tenuisporynit Krassisporynit Mikrosporynit Makrosporynit Pila Alginit Reinschia Alginit Sklerotyt Karbargilit Karbankeryt Łupek palny Skała płonna Łupek palny Skała płonna Karbo mineryt Karbosilicyt Karbopiryt Karbopolimineryt Skała płonna Inertynit I Mikrynit Makrynit Semifuzynit Fuzynit Sklerotynit Inertodetrynit Pirofuzynit Degradofuzynit Fungosklerotynit Plektenchyminit Korposklerotynit Pseudokorposklerotynit Węgiel Węgiel sapropelowy Kennel Boghed

12 EXAMPLES OF MACERALS

13 COAL CONSTITUENTS Coal consists three ingredients: - organic matter (combustible), - mineral matter, - moisture.

14 CHEMICAL STRUCTURE OF COAL (organic matter) Benzene ring

15 COAL STRUCTURE

16 EVOLUTION OF COAL STRUCTURE WITH THE RANK typical structures of coal rank of coal lignite higher carbonization higher compression lower oxygen content coals for power generation coking coal anthracite

17 CLASSIFICATION OF COAL

18 REASONS FOR CLASSIFICATION OF COAL variable characteristics of coal (complex material) different boiler furnaces in use, applications in chemical technology and metallurgy, extended trade of coal

19 STANDARDS USED IN COAL CLASSIFICATION Origin and parameters of coal: (Polish Standards PN) upper caloric value UCV ( in Polish Q s: PN-81/G or PN-ISO 1928:2002), blow up index (PN-81/G-04515), volatile matter content VM (PN-G-04516:1998), dilatometric index (PN-81/G-04517), coking index (PN-81/G-04518).

20 ANALYSIS OF COAL Proximate analysis content (wt%) of: - moisture M, - ash A, - volatile matter VM. - caloric values: HCV and LCV. Ultimate analysis: (wt%): - elements content: C, H, O, S, N, P,...(wt%)

21 STATE OF SOLID FUELS Analytical of air-dry (a), when moisture in coal is in equilibrium with moisture of ambient air, Dry (d lub wf), after 2-3 hours of drying at the temperature of o C, Dry and ash free (daf lub waf). Raw (as burnt in boiler) (r).

22 Example of A and Qi in raw state (r), in dry state (d) and dry-ash-free state (daf) of lignite Value W r t A r Q r i A d Q d i Q daf i % % kj/kg % kj/kg kj/kg Min Medium Max

23 Calculations of results of analysis of coal (solid fuels) Type of conversion From raw state r Raw From analytical state a 1 From dry state d r r 1 W +W r 1 W 1 r 1 W A From dry ash free state daf 1 Coefficient of conversion: Analytical a 1 1 W W 1 r a a r a 1 W 1 a 1 W A 1 Dry d 1 r 1 W 1 1 a 1 W a Dry ash free daf 1 r 1 W 1 A a a 1 W A 1 1 d 1 A 1 A 1 d 1 r

24 COAL CLASSIFICATION ACCORDING TO ORIGIN AND COAL RANK Coal class Content of C Peat: 52-60% Lignite: 58-77% Bituminous coal: 76-93% Anthracite: 91-93%.

25 POLISH CLASSIFICATION OF COAL In Poland coals are divided on: groups (classes) types, sorts.

26 GROUPS (CLASSES) Group is described by the two-digit number: - first digit determines the group according to the coal rank, - the second digit determines the position in the group.

27 COAL GROUPS (CLASSES) Wood: Peat: Lignite: Bituminous coal: Anthracite: 41 and higher Graphite: 50

28 Type of coal Volatile matter content V daf PN-81/ G Classifying measurements Coking ability RI PN-81/ G-4518 Coals for power generation Dilatometric index PN-81/ G Blow up index SI PN-81/ G Upper caloric value Q daf PN-81/ G Name Mark % % kj/kg Flame coal More than 28 Over or equal to 5 Over or equal Over Applications of coal Do wszystkich typów palenisk pyłowych; do czadnic pulverised coal furnaces; gas generatrors Gaseous -flame coal Gaseous coal More than 28 More than 28 Over 5 to 20 Over 20 to 40 Over 40 to 55 Without standar d Without standar d Without standard Do wszystkich typów palenisk; do wytlewania i do czadnic all types of coal furnaces; gas generatrors Do palenisk rusztowych, komorowych i wszystkich typów palenisk pyłowych; węgiel do wytlewania i do gazowni grate furnaces, pulverised coal furnaces; gasgeneratrors Do palenisk rusztowych i wszystkich typów palenisk pyłowych; do pieców przemysłowych o szczególnych wymaganiach; do gazowni i do mieszanki do produkcji koksu w koksowniach grate furnaces, pulverised coal furnaces, industrial kilns; gas generatrors; coke production

29 Coal sorts sort group / name /symbol grain size upper / lower

30 CHARACTERISTIC OF MAJOR COMPONENTS OF COAL

31 COAL COMPONENTS Coal is combined with three components: Moisture (M) Mineral matter (A) Combustible (organic) matter Moisture and mineral matter are ballast.

32 MAIN ELEMENTS IN COAL Organic matter: - basic: C and H, - important: O, S, N and P - trace content: the rest.

33 Thermal decomposition of coal COAL PYROLYSIS Coal particle Volatile matter Temperature Char Coal pyrolysis is thermal decomposition of coal at the temperature of C, depending on the coal type. Results of pyrolysis: - evaluation of volatile matter - remaining COMBUSTION char. AND FUELS

34 char volatile matter organic matter ash mineral matter coal in dry state c + h + o + n + s + a + w = 1 coal in air-dry (analytical) state coal in raw state w from decomposition of mineral matter inherent moisture in air-dry state transient moisture (surface moisture) COAL COMPONENTS

35 ANALYSIS OF ORGANIC FUELS Fuel C H O N + S VM content, % Wood Peat Lignite Hard coal Anthracite , , ,8 0,8 trace

36 INORGANIC MATTER IN COAL (2-60%) Inorganic components in coal are classified: - primary vegetable ash (inner m.m. inherent plant matter that formed coal) - secondary minerals (outer m.m.: rocks and sand and clay) (mineral matter deposited by wind and water or by water through the seams) percolation of Inorganic matter of the primary type is dispersed in coal impossible to remove by the mechanical methods. Inorganic matter of the secondary type usually consists of minerals present in surrounding of a coal deposit.

37 SECONDARY INORGANIC MATTER Main constituents (mainly minerals) of the secondary inorganic matter: - quartz, - clay minerals (kaolinite, illite,...) - oxides (hematite) - carbonates (dolomite, calcite,siderite,...) - sulphides (pirite, marcasite, zink suphide,...) - phosphates (apatite) - others (chlorides, sulphates, nitrates, heavy metals).

38 MOISTURE IN COAL (5-60%) Total moisture includes: - air-dry loss moisture (transient) (loss of weight resulted of partial drying of coal) (not linked to organic matter, can be removed by drying at room temperature air-dry state or analytical (a)), - inherent moisture (is connected with the substance of coal, and can be removed from coal by heating it at the temperature in the range of o C (dry state (d))). Water of hydratation of mineral matter.

39 SOME ELEMENTS IN COAL Carbon C: 50-93% Hydrogen H: 2-5% Oxygen O: 1-3% Sulfur S: 1-5 (11)% in sulphites (FeS 2 ) in sulphates (CaSO 4, FeSO 4 )

40 Polish bituminous coal for heat and power production (type 31-33) Coal mining region LCV kj/kg Ash content % Sulphur content % Moisture % Jaworznicki Mikołowski Dąbrowskosiemianowski Katowickochorzowski Rybnicki Lubelski

41 CHARACTERISTICS OF POLISH BITUMINOUS COALS TYPE LCV (W u ) = MJ/kg A = 7-25% S = 1.2% N = %

42 Polish lignites Coal mining region LCV kj/kg Ash content % Sulphur content % Moisture % Turoszowski Koniński Pątnowski Adamowski Bełchatowski ,2 20 5,8 6,3 10,6 9,8 10,6 0,60 0,25 0,35 0,78 0,25 0,

43 CHARACTERISTICS OF POLISH LIGNITES LCV (W u ) = A = (aver.8.5) MJ/kg 4-25 (aver.12.0)% S = (aver. 0.7)% N = %

44 BITUMINOUS COAL-FIELDS IN POLAND Coal basins: - Upper Silesia, - Lower Silesia - lubelskie Reserves: Total reserves: 30 bln Mg 100 bln Mg

45 Reserves and total reserves of bituminous coal in Poland Basin Reserves, % Total reserves, % GZW DZW LZW

46 LIGNITE COAL-FIELDS IN POLAND Coal basins: - adamowsko-konińskie - bełchatowskie (Szczerców) - turoszowskie - sieniawskie. Total reserves: Reserves: Operational reserves: 40 bln Mg bln Mg 3.5 bln Mg

47 LIGNITE COAL FIELDS IN POLAND Deposits with coal mines Other discovered deposits

48 RESERVES AND TOTAL RESERVES OF COAL Fuel World bln Mg Poland bln Mg Bituminous coal reserves total reserves Lignite reserves total reserves

49 PRODUCTION OF COAL Yearly production of coal in Poland and in the world Type of coal World 10 9 Mg Poland mln Mg Bituminous (hard) (2009) Lignite Polish import/ export of hard coal in 2008 Export 7 mln Mg Import 10 mln Mg

50 Reserves and production of bituminous coal in Poland Reserves ( x 10 9 t) Production ( x 10 6 t) Year

51 Production and the use of coal in Poland Bituminous coal Production Import Production/export Amount, mln Mg The use: - production of other fuels - direct use - export Lignite Production of lignite was approx.58.2 mln Mg in 2002 r. and it was used for electrical power production.

52 Bituminous coal price in USD/tonne $ / t

53 Costs of heat and electricity generation in Poland Cost of heat generation PLN per 1 GJ Cost of electicity generation PLN per 1 MWh including CO 2 capture from lignite from hard coal from natural gas from COMBUSTION AND lignite FUELS from hard coal from natural gas