coal basic

8/12/2019 Coal Basic

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COAL


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Chemical Structure of Coal(Depending upon source, structure may be widely different)

Anthracite Coal

Carbon 92-98%
http://en.wikipedia.org/wiki/File:Coal_anthracite.jpg


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Coal is a stored fossil fuel, occurring in

layers in the earths crust, which has

been formed by the partial decay of plant materials accumulated millions of

years ago and further altered by the

action of heat and pressure.

COAL : DEFINITION


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COAL FORMATION


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IN SITU THEORY

DRIFT THEORY - Flood /Tsunami type wave

(velocity 800 km/h)

300 million of years (earth is 4.6 billion years old)

15-20 m OF PLANT MATERIAL= 1 m OF COAL SEAM

In INDIA 30 m seam of coal has been found

THEORIES OF COAL FORMATION

450-600 m of plant material might have

accumulated at that place.

(Taipei 101:509 m tallest building in world)


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COALIFICATION

COAL % C C H O Heating

value(MJ/kg)

Cellulose

WoodPeat

Lignite

Brown coalBituminous coal

Anthracite

Graphite

44.5

50.059.9

61.8

69.578.7

91.0

100

100

100100

100

100100

100

100

13.9

12.010.0

7.8

7.96.0

4.7

0.0

111

8857

54

3621

5.2

0.0

-

19.7718.66

20-25

27.2032.10

32.56

32.91

Time


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COAL RANKS

1.Peat: starting point of coal formation

does not come in the category of coal

Carbon: 60-64%; Oxygen:35-30%

2. Lignites: mark the transition of peat to coal

Carbon: 60-75% ; Oxygen: 30-20%

Colour: black, brown, earthy

Disintegrate very easily

Briquetting is done

Neyveli Lignite Corporation, Chennai, Tamilnadu

Possesses largest reserves of Lignite in India

Electricity generation: 2490 MW
http://images.google.com/imgres?imgurl=http://www.justsaynotolignite.co.uk/lignite.jpg&imgrefurl=http://www.justsaynotolignite.co.uk/lignite.html&usg=__vdmF86ucq--GUf_AwFaVc5ib_XQ=&h=960&w=1280&sz=92&hl=en&start=18&tbnid=s-wZCZPml--v7M:&tbnh=113&tbnw=150&prev=/images%3Fq%3DLignite%26gbv%3D2%26hl%3Denhttp://images.google.com/imgres?imgurl=http://www.depiazzi.com.au/images/mulches/mulches_big/karri%2Bpeat.jpg&imgrefurl=http://www.depiazzi.com.au/mulches.html&usg=__EUUcTRCLWqr5AmPleo6vk3P9nRw=&h=1704&w=2272&sz=912&hl=en&start=9&tbnid=1-Z-6RxIB3SzMM:&tbnh=113&tbnw=150&prev=/images%3Fq%3DPeat%26gbv%3D2%26hl%3Den%26sa%3DGhttp://en.wikipedia.org/wiki/File:Peat_Lewis.jpg


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COAL RANKS contd

3. Bituminous coals

Sub-bituminous:

Between lignites and bituminous

Carbon: 75-83% ; Oxygen: 20-10%

No caking power (Briquettes can not be made)

Bituminous: black and banded

Industrial and domestic usage

Carbon: 75-90%: Oxygen:10-5%

Semi-bituminous:

Between bituminous and anthracite

Metallurgical coke formation

Carbon: 90-93%; Oxygen:4-1%


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COAL RANKS contd

4. Anthracites

Highest rank of coal

Extreme of metamorphosis

from the original plant material

Carbon: 93+%: Oxygen: 2-1%Caking power zero

Unusual coalsCannels: found rarely; high hydrogen content: burnwith smoke and bright flame; does not fall in any category.

Torbanites: fine grained coal, named after Torbane Hillof Scotland, rich in paraffin oil.
http://en.wikipedia.org/wiki/File:CannelCoalWhite.jpg


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Unusual Solid Fuel

(Methane Clathrate)

Burning Ice

1 mole methane in 5.75 moleH2O

Available in Deep sea (methanefrom trench + cold water + highpressure) and at the lower ice

layer in Antarctica It is expected that 15,000 Gt

(211015 m3) of methane isavailable in this form (as

compared to 1,000 Gt of Coal)


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Country Million tonnes% of world product ion

China 2380 39.75

USA 1053.6 17.59

India 447.3 7.47

Australia 373.8 6.24

South Africa 256.9 4.29

Canada 62.9 1.05

United Kingdom 18.6 0.31

Pakistan 4.3 0.07

Japan 1.3 0.02

Total of the world 5,986.90 100

WORLD PRODUCTION OF COAL IN YEAR 2006


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WORLD PRODUCTION OF COAL IN YEAR 2006

China

USA

India

AustraliaJapan

PakistanCanadaSouth

Africa

United

Kingdom


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WORLD TOP TEN COAL PRODUCING AND

CONSUMING COUNTRIES

1 quadrillion=1000 trillion

1 Btu=1.055 kJ
http://upload.wikimedia.org/wikipedia/commons/8/85/T629172A.gifhttp://upload.wikimedia.org/wikipedia/commons/8/85/T629172A.gifhttp://upload.wikimedia.org/wikipedia/commons/8/85/T629172A.gifhttp://upload.wikimedia.org/wikipedia/commons/8/85/T629172A.gif


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Type of coalTOTAL

RESERVE

PROVED

RESERVE

INDICATED

RESERVE

INFERRED

RESERVE

COKING 32 17 13 2

NON-

COKING223 81 105 36

TOTAL 255 98 118 38

COAL RESERVES OF INDIA

Source: MoC

Years to consume this coal with present rate: 600

(As on 1.1.2007

in billion tonnes)

Cokes are the solid carbonaceous material

derived from destructive distillation oflow-ash, low-sulfur bituminous coal.
http://images.google.com/imgres?imgurl=http://www.elkvalleycoal.ca/upload/pull_quote/5/01/img0004.jpg&imgrefurl=http://blog.chosun.com/jktbae/3247094&usg=__SpRVtNfhUkKeVdkJLvXrcxmq_AE=&h=339&w=300&sz=33&hl=en&start=14&tbnid=EP8vyCi5PJEqHM:&tbnh=119&tbnw=105&prev=/images%3Fq%3DCoking%2Bcoal%26gbv%3D2%26hl%3Den


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State Proved Indicated Inferred Total % of total

Jharkhand 36881 31094 6339 74314 29.11

Orissa 17464 30239 14296 61999 24.29

Chhattisgarh 10182 26826 4443 41451 16.24

West Bengal 11454 11810 5071 28335 11.10

Madhya Pradesh 7584 9259 2934 19777 7.75Andhra Pradesh 8475 6328 2658 17461 6.84

Maharashtra 4856 2822 1992 9670 3.79

Uttar Pradesh 766 296 0 1062 0.42

Meghalaya 118 41 301 460 0.18

Assam 315 27 34 376 0.15

Bihar 0 0 160 160 0.06

Arunachal Pdesh 31 40 19 90 0.04

Sikkim 0 55 18 73 0.03

Nagaland 3 1 15 19 0.01

Total 98129 118838 38280 255247 100

COAL RESOURCES OF STATESIN MILLION TONNES Jan 1, 2007

Proved: boreholes (1200m deep) @ 400 m

Indicated & Inferred: boreholes @ 1-2 km


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Coking coal (carbon: 81-91%)

Non-coking coal

GRADING OF INDIAN COAL

Grade Industry Ash %I steel


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High ash content (up to 50%)

Lower heating/calorific value

Inferior quality but suitable for power gen.

GRADING OF INDIAN COAL

Grade UHV, kcal/kg Ash %

A >6200


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Nationalization in 1971 Coal companies are paying the

royalty to states

This varies from Rs 90-250/tonne

The rate is dependent of coal

grade Rates are 16 August 2002 onwards

ROYALTY TO STATES


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IMPORT OF COAL

Coking and non-coking coals being imported

Year Coking Non-coking Total

1991/92 5.27 0.66 5.93

1996/97 10.62 2.56 13.18

2000/01 11.06 9.87 19.70

2003/04 12.99 8.69 21.68

2005/06 16.89 21.70 38.59

2006/07 22.00 23.00 45.00

In million tonnes


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Proximate analysis

Ultimate analysis

Heating/calorific value

ANALYSIS OF COAL


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1. Moisture content: 105 -110 oC

2. Volatiles: 92515 oC for 7 min time (with lid)

3. Fixed carbon: by difference

4. Ash: 80015 oC (without lid)

PROXIMATE ANALYSIS

IS:1350-I (1984)

REPORTING: AS RECEIVED BASIS, MOISTURE FREE

BASIS/DRY BASIS OR DRY ASH FREE BASIS


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A sample of finely ground coal of mass 0.9945 g wasplaced in a crucible of8.5506 g in an oven, maintained at

105 oC for 4.0 ks. The sample was then removed, cooled in

a dessicator and reweighed; the procedure being repeated

until a constant total mass of 9.5340 g was attained. Asecond sample, of mass 1.0120 g in a crucible of mass

8.5685 g was heated with a lid in a furnace at 920 oC for

420 s. On cooling and reweighing, the total mass was

9.1921 g. This sample was then heated without a lid in thesame furnace maintained at 725 oC until a constant total

mass of 8.6255 g was attained. Calculate the proximate

analysis of the sample and express the results on as

sampled and dry, ash-free basis.

EXAMPLE OF PA


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MOISTURE (from first sample)

mass of sample = 0.9945 g

mass of dry coal = (9.5340-8.5506) = 0.9834 g

mass of moisture = (0.9945-0.9834) = 0.0111 g

% moisture = 0.0111 100/0.9945

= 1.11 %

EXAMPLE OF PA contd..

ASH (from second sample)

Mass of sample = 1.0120 g

Mass of crucible = 8.5685 g

Heating up to 920C in absence of air removes volatile matters,subsequent heating up to 725C in presence of air burns all

fixed carbon of the sample leaving behind ash in the crucible.

Mass of ash (remnant in crucible) = (8.6255 - 8.5685)

= 0.0570 g

% ash = 0.0570 100/1.0120 = 5.63 %


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VOLATILE MATTERInitial mass of sample + crucible = 1.0120 + 8.5685 = 9.5805 g

Final mass after heating up to 920C (without air) = 9.1921 g

Mass of volatile matter + moisture = Initial Final mass

= (9.5805-9.1921) g

= 0.3884 g

% Moisture + Volatiles = 0.3884 x 100/1.0120

= 38.3794 %

% VOLATILE MATTER = 38.3794 1.11 (% Moisture)

= 37.26 %


FIXED CARBON

% FC = 100 - % VM - % ash - % moisture

= 100 37.26 - 5.53 - 1.11

= 55.98 %


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Proximate analysis as received basisMoisture : 1.11 %

Ash : 5.63 %

Fixed carbon : 55.99 %

Volatile matter : 37.26 %

Proximate analysis on dry, ash free basis

Moisture + ash = 1.11 + 5.63 = 6.74%

Fixed carbon: 55.99x100/(100-6.74) = 60.04 %

Volatile matter: 37.26x100/(100-6.74) = 39.95 %



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1. Carbon

2. Hydrogen

3. Oxygen

4. Sulfur :0.5-2.50 %

5. Nitrogen :1.0-2.25 %6. Phosphorus :0.1%;Blast Furnace:


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1. Calculated from proximate analysis2. Calculated from ultimate analysis

3. Experimental determination

HEATING VALUE

1. Gross/High heating value

2. Useful/low heating value

Hydrogen Water (gas/vapor or liquid phase)

Carbon Carbon Dioxide (gas phase)

Latent heat of vaporization of water: 2.26 MJ/kg


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1. Calculated from proximate analysis

HEATING VALUE

TAYLOR AND PATTERSON RELATIONSHIP

HV=4.19 (82FC+ a VM) kJ/kg

Where FC and VM are on dry ash free basis and a is

an empirical constant which depends on the VMcontent of coal.

VM 5 10 15 20 25 30 35 38 40

a

145 130 117 109 103 98 94 85 80

80

90

100

110

120

130

140

150

160

170

0 10 20 30 40


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2. Calculated from ultimate analysis

HEATING VALUE

DULONG FORMULA

HV=338.2C+1442.8(H-O/8)+94.2S kJ/kg

Where C, H, O and S are the % of these elements on

dry ash free basis.


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3. Experimental determination: Bomb calorimeter

HEATING VALUE

IS:1350-II (1970)

solid /liquid samples can be analyzed

1 g air dried sample is burnt in a bomb in oxygen

atmosphere rise in temperature gives the heat liberated and

heating value is determined after doing the

corrections for resistance wire and thread.

microprocessor based bomb calorimeters are now

available

BOMB OF CALORIEMETER


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BOMB OF CALORIEMETER

VARIOUS COMPONENTS OF BOMB


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VARIOUS COMPONENTS OF BOMB

CALORIMETERIC EQUIPMENT


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ROUTES OF GENERATION OF HEAT AND

POWER FROM COAL

1. Direct use as thermal energy in heating processes,furnaces and domestic heating by open fires

2. Transfer of the heat to a thermal fluid and application of

the latter for heating and power e.g., steam for heating inprocess industry, central heating and electricity

generation by steam turbines

3. Gas turbine route to electricity generation4. Conversion to gas/liquid fuels and subsequent usage in

IC engines/turbines (gas/steam)


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ROUTE I (Direct Heating)

Domestic cooking (Chula at tea stalls, dhaba, bakery)

Space heating (Fireplace)

Lime and brick kilns (Direct heating of stack)

Ceramic industry (Oven/Furnace)


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Generation of steam in a boiler Space heating by transferring heat of steam to air

Process industry : Cogeneration is employed

Utility services : steam turbines used

ROUTE II (Thermal Fluid)

GOVERNMENT ALLOWED ELECTRICITY GENERATION

BY PRIVATE DEVELOPERS

Tariffing

Wheeling

Banking

SUPERCRITICAL BOILERS: A RECENT CONCEPT

Critical pressure: 218 bar (21.8 MPa); Critical temperature: 374oC

Mark Benson; in 1922 Patent was granted

22 MPa pressure ; = 1-T1/T2 0.53


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ROUTE III

Electricity

to grid

Preheated air

Air

T

urbine

e

xhaust

CompressorGas turbine Alternator

Vent

Heat

exchangerPulverizer

Coal

Combustionchamber


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ROUTE III

Electricity

to grid

Preheated air

Air

T

urbine

e

xhaust

CompressorGas turbine Alternator

Vent

Heat

exchanger

Combustionchamber

Gasifier and gas

cleaning unit

Coal


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ROUTE IV (Pyrolysis / Gasification)

1. Partial Gasification or Pyrolysis /coking/carbonization / destructive distillation

(heating in the absence of air)

Solid

Liquid

Gas

2. Complete gasification with air/oxygen Gas


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PYROLYSIS

Coke (solid fuel) maximum; classical domestic smokeless fuel

production

Liquid fraction for chemicals recovery/liquid fuel

Coke for metallurgical furnaces; gas yield high; liquid low

Low temperature carbonization 500-700 oC

High temperature carbonization >900 oC

Medium temperature carbonization 700-900 oC


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PYROLYSIS

Pyrolyser

Coal

Water in

Water out

Condenser

Gas

for IC engines

Gas turbines/

thermalapplications

Coke

Gas for heating of pyrolyser

Flue gas

Pretreatment

unit

Liquid

fraction

Coal tar

Liquid fuel

Chemicals


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GASIFICATION

33

12x3=36 kg1k mole

=1000.R.T/P (m3)

=22.41 Nm3

18 Liter


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(Air Separation

Unit)


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ROUTE IV BERGIUS PROCESS


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ROUTE IV BERGIUS PROCESS

1. Bergius process

Friedrich Karl Rudolf Bergius (Germany) in 1913,

Nobel Prize in 1931 (Shared with Carl Bosch)

By end of World war II most of the fuel for

German army was produced by this method.

Hydrogenation of vegetable oils

2. Fischer-Tropsch process

Franz Fischer and Hans Tropsch in 1926, Germany

Coal is hydrogen starved/hydrogen needs to be added to make it

liquid (directly or indirectly)

BERGIUS PROCESS


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BERGIUS PROCESS

Pulverizer

Coal pasting

unit

HydrogenCoal

Fractionating

column

Bergius

Reactor

Heavy fraction

HCs

T=400-500 oC

P= 20 -70 MPa

Catalyst=Tin

Conver.=97%

F T PROCESS


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F-T PROCESS

Gasification

unit

Syn gas

Cleaning

Coal

Fractionating

column

F-T

Reactor

HCs

T=150-250 oC

P= 1 -25 Mpa

Catalysts : Fe, Co

Syn gas

(Large number of patents worldwide)

F T PROCESS (COMMERCIAL PLANTS)


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F-T PROCESS (COMMERCIAL PLANTS)

South Africa Oil and Gas

Company

1950 established

Oldest plant proving the F-T

process viability

Presently engaged in Qatar,

Iran and Nigeria in similarprojects

F T PROCESS (COMMERCIAL PLANTS)


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F-T PROCESS (COMMERCIAL PLANTS)

F T PROCESS(COMMERCIAL PLANTS)


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F-T PROCESS(COMMERCIAL PLANTS)

UNDERGROUND/ IN SITU COAL


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GASIFICATION

A process applied to the non-mined coal seams

Injection and production wells are drilled

End gas mix depends on type of coal seam

Air/ oxygen can be used for gasificationSyn gas can be used for power generation in combined cycle

Syn gas can be converted to chemicals/fuel by F-T process



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GASIFICATION

Source: World Coal Institute

COAL COMBUSTION AND ENVIORNMENT


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Global warming

Green house gases: water vapor, carbon dioxide,

methane, nitrous oxide, HFCs (hydrofluorocarbons),PFCs (perfluorocarbons), SF6 (Sulphur Hexafluoride)

SF6 is 22, 200 more potential than CO2 Carbon dioxide gas: main culprit from fossil fuels; not

from biomass

Intergovernmental Panel on Climate Change (IPCC)

Nobel Peace Prize 2007 : R. K. Pauchari and Al Gore

Reduction in Carbon Dioxide emissions

G8 meeting in Japan in July 2008



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Carbon Dioxide Emissions and Carbon Dioxide Concentrations (1751-2004)

Present CO2 level:483 PPM



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Global Carbon Cycle (Billion Metric Tons Carbon)



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U.S. Anthropogenic Greenhouse Gas Emissions by Gas,

2006 (Million Metric Tons of Carbon Dioxide Equivalent)

ULTIMATE SOLUTIONS


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ULTIMATE SOLUTIONS

Fuel cells: Chemical to electrical conversion

Solar: photovoltaic

Hybrid vehicles: Honda introduced in India

coal basic

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