1. Huma Nazir
M.Phill 2nd Smester
Institute of Chemistry Punjab University Lahore

2. Fuel
 Fuel is a substance which, when burnt, i.e. on
coming in contact and reacting with oxygen or
air, produces heat.
 The substances classified as fuel must
necessarily contain one or several of the
combustible elements : carbon, hydrogen,
sulphur, etc.
Chemical •Heat
energy
energy
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3. Wood Peat Lignite Coal
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4. Contents of Wood
 Cellulose
 Lignin
 Resins
 Inorganic materials
 Water (25-60%)
Composition of dry wood:
C 50%
O 35%
N 7%
H 6%
 Ash 2%
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5.  Calorific
value 6500-9200 BTU/pound
Carbonization of Wood
combus •Co,H2
tibles
•CH4
Saturate
d
hydroca
rbons
Non-
combus
•CO2
tibles
•N2
Wood
charcoal
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6. Advantages of Wood
Burns readily
Soot and ash produced is small
Ash is reused
Easily available
Suitable calorific value for domestic use
Disadvantages of Wood
High percentage of water (decrease calorific
value)
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7.  Decayed vegetation (moist condition)
 Usually accumulates slowly, at the rate of about
a millimetre per year
General Composition:
Volatile matter 10.4%
Fixed carbon 4.6%
Moisture 85%
Composition in dry condition:
C 57%
H2 6.1%
Oxygen 34.9%
Ash content(mostly) 5-10%
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8.  Greater the decomposition greater the carbon
lesser the oxygen
 Average Calorific value 6000-9000 BTU/lb
Tar
wax
Fuel gases
(NH4)2SO4
Peat coke
Destructive
distillation
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9. Advantages of Peat
 Used as fertilizer
 As packing material
 As boiler fuel in form of braquettes
Disadvantages of peat:
 High water content
 Burns slowly
 Low calorific value
 Not economical
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10.  Immature coal
 May be amorphous, fibrous or woody in
texture
 It contain small quantity of resins, moisture
(25-40%), high percentage of volatile
matter(ignites)
 Characterized by high content of
noncombustible matter.
 Burns with long smoky flame
 Calorific value 6000-7500 BTU/lb
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11. tar
carbonization
Synthetic
petrol
High pressure
hydrogenation
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12.  Heating boilers
 Evaporating pans in industry
 For domestic purposes
 Fertilizer manufacture
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13. 300 million
years
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14.  Highly complex organic matter with
 Varying quantity of water
 Nitrogen (0.75-1.75 %)
 sulphur
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15. On the basis of origin
 Humic or Banded coal
 Sapropelic coal
Different grades of coal are
 Anthracite (86-88% C)
 Bituminous (78-86% C)
 Sub-bituminous coal or black lignite
 Pulverised coal
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16.  Finalstage of coal formation
 Hard, compact, black coloured coal, good
semimetallic lusture
 Highest % of fixed C
 High Calorific value ( 14000-15000 BTU/lb)
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17.  Advantages
Intense heat with no smoke
Useful for metallurgy
For slow combustion stoves for domestic
purposes
 Disadvantages
High ash contents
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18.  Dullblack coal
 Calorific value < bituminous coal
 Denser and harder than lignite
 Moisture content 10-25%
 Calorific value 7000-15000 BTU/lb
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19.  Commercial rank coal
 Very hard and black
 Burns with yellow smoky flame
 Distillation product is coke(remove sulfur and
ash contents)
 Brittle
 High calorific value (11000-15000BTU/lb)
 Low moisture contents
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20. On the basis of fuel ratio
 Low volatile coal
 High volatile coal
 Super bituminous coal (2.5-5.0) (calorific
value = 12000-15500BTU/lb)
 HVC burns with long flames so used in gas
industry, coal tar distillation,glass industry
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