This document discusses different types of fuels including their classification, characteristics, and uses. It covers solid fuels like coal and wood, liquid fuels like petroleum and biodiesel, and gaseous fuels like natural gas. Coal is classified based on carbon content and other properties into peat, lignite, sub-bituminous coal, bituminous coal, and anthracite. Petroleum is refined through fractional distillation to produce useful fractions like gasoline, kerosene, diesel, and fuel oils. Characteristics of good fuels and methods of determining calorific values are also outlined. Alternative fuels discussed include ethanol, biodiesel produced through transesterification of vegetable oils, and compressed natural gas.

1. By
Dr. Sandip K. Jagadale
Assistant Professor in Chemistry
S. B. Patil College Of Engineering, Indapur

2. FUEL
• Def:- A combustible substance which on proper
burning gives large amount of heat , which can
be used economically for domestic & industrial
purpose.
• Classification of fuel :
A) On the basis of source
1) Natural / Primary 2) Synthetic/Secondary fuel
B) On the basis of physical state:
1) Solid 2) Liquid 3) Gas

3. Natural and Manufactured Fuels
Natural Fuels Manufactured Fuels
Solid Fuels
Wood
Coal
Oil shale
Tanbark, Bagasse, Straw
Charcoal
Coke
Briquettes
Liquid Fuels
Petroleum Oils from
distillation of petroleum
Coal tar
Shale-oil
Alcohols, etc.
Gaseous Fuels
Natural gas Coal gas Producer gas
Water gas
Hydrogen
Acetylene
Blast furnace gas
Oil gas

4. CHARACTERISTICS OF GOOD FUEL
1) High calorific value
2) Moderate ignition temperature
3) Moderate velocity of combustion
4) No/ low moisture content
5) No/ Iow ash content
6) Combustion of fuel controllable
7) Cheap, easily available
8) Easy storage & transportation
9) Harmless products of combustion
10) No/ low volatile matter
11) Use in IC engine
12) Air requirement

5. Calorific value
• Def: Total amount of heat liberated when a unit
mass or unit volume of fuel is burnt completely.
• Given by TWO ways :
• 1) Gross / higher Calorific value (GSV/HCV)
• 2) Net / lower Calorific value (NSV/LCV)
• GCV : It is defined as the amount of heat obtained
on complete combustion of unit mass of solid or
liquid or unit volume of a gaseous fuel at STP and
the products of combustion are cooled to 15 C
( Room temperature).

6. NCV / LCV
• It is defined as the amount of heat obtained
practically on complete combustion of unit mass
of solid or liquid or unit volume of a gaseous
fuel at STP and the products of combustion are
allowed to escape with some heat.
• Relation between GCV & NCV
GCV = NCV + ( 9 X h X latent heat of water) / 100
GCV = NCV + 0.09 X H X 587 cal / gm.
NCV=GCV- 0.09 X H X 587 cal / gm.

7. Calorimeter
• Principle : Total heat liberated by complete
combustion of known amount of fuel is absorbed
by the known mass of water in Calorimeter .
From the rise in temp. of water the Calorific value
of fuel can be calculated.
1) Bomb calorimeter
Principle : A known weight of solid/liquid fuel is taken
in the presence of excess oxygen in the closed pot, and
the products of combustion are cooled to get GCV of
the fuel
2) Boys calorimeter

8. Bomb calorimeter
• A bomb calorimeter consists of ,
1) Bomb pot : Cylindrical, strong stainless steel pot
with lid, fitted air tight to Bomb pot. Two electrodes
fitted to lid & oxygen inlet valve at centre. One electrode
provided with ring to hold crucible containing fuel and
resistance wire in loop form touches the fuel.
2) Calorimeter: made up of Steel or Copper in which
bomb pot is kept, known volume of water is added so
that bomb pot is completely deep. Beckman
thermometer to measure temperature of water in
calorimeter & stirrer for stirring water.
3) Water & Air jackets: Calorimeter is surrounded by
water & air jacket to avoid heat loss due to radiation

9. Bomb calorimeter

10. • 4) Accessories : Pellet press to form pellet of fuel,
Oxygen cylinder to fill oxygen in bomb pot at
pressure 25 Kg/ cm sq. & D.C battery of 6 Volt to
start combustion of fuel.
• Working : weigh pellet of solid fuel, add 10 ml
water in bomb, fill with oxygen, place bomb in
calorimeter, add known volume of water, place
calorimeter in water jacket with Beckmann
thermometer & stirrer, make electrical
connections & pass current form battery for 5-6
sec. ,wire burns and fuel also, note the maximum
temperature reached and Average fall of
temp./min.

11. Calculations
• Let, mass of the fuel = x gm.
• Mass of water in calorimeter = W gm.
• Water equivalent of calorimeter set = w gm.
• G.C.V of fuel = L cal./gm.
• Rise in temperature of water = (t2 - t1)
So,
Heat liberated by burning fuel = Heat absorbed by
water and calorimeter
Then add corrections in formula……………….

12. Boys calorimeter
• Construction : it consists of following parts….
• 1) Gas burner : to burn known volume of gas.
• 2) Combustion chamber ( Chimney) : around the
burner with copper tubing inner and outer side.
Water enters from top outer coil & moves to
bottom of chimney then goes up through inner
coil.
• 3) Thermometer : Two thermometers
• 4) Insulating cover : Assembly is covered with
insulator to detach combustion chamber from
atmosphere.

13. Boys calorimeter

14. • Volume of gas burnt in time ‘t’ = V m3
• Wt of cooling water circulated in time ‘t’= W kg
• Initial temperature of incoming water =T1
0C
• Final temp. of outgoing water =T2
0C
• Thus rise in temp. = (T2 - T1) 0C
• Wt. of water produced from steam
condensation = m kg
• Let, L = GCV

15. Solid Fuels: Coal
• Coal is highly caboneous matter formed from
vegetable matter buried in geomorphic
changes, under pressure, by action of aerobic
& anaerobic bacteria for a long time.
Wood
Lignite Bituminous Anthracite
Peat
Aerobic Bacteria
Anaerobic Bacteria
/ Acidic condition
Anaerobic Bacteria / long
time alkaline condition

16. Conversion from Peat to Anthracite , there is
Increase in: %C, CV, density, lusture, hardness,
black color intensity.
Decrease in: % M, VM, % of N, H, O, S, ash

17. Classification of Coal
Peat :- i) Contains 57% C, 6% H, 35% O, 3-6%
Ash.
ii) Brown and fibrous in texture.
iii) Contains High % water & dried peat contains
15-25 % moisture.
iv) Cal. Value is 5400 cal./ gm. & has low density.
Uses:
i) As a domestic & industrial fuel.
ii) Used for soil conditioning.
iii) Used for steam raising, thermal insulation,
packing, gas purification & some times for power
generation.

18. Lignite
• Composition : 65-70% C, 5% H, 20% O,
10-15% Ash.
• Brownish black & more compact than peat.
• Contains 45-50% volatile matter & burn long flame
• C.V. 6000-6700 cal./gm.
Uses :
• After briquetting , used as domestic ,industrial fuel
• Used to produce producer gas.
• For power generation.
• On carbonization, gives tar used for making road.

19. Peat
Anthracite
Bituminous Coal
Lignite

20. Bituminous coal
• Bituminous coal: Contains 70-90% C, three
types
• Sub-bituminous coal :
• Non- caking coal
• Composition : 70- 75% C, 35 – 40 V.M% .
• Characters between lignite and bituminous coal.
• Harder and denser than lignite, black in color.
• C.V. 7000 cal./gm.
Uses :
• Used as domestic ,industrial fuel

21. Bituminous coal
• Composition : 75-85 % C, 20-30 % VM,
• black, dense and hard
• Cubical fracture structure
• C.V. 8000-8500 cal./gm.
Uses :
• used as domestic ,industrial fuel
• Used as metallurgical coke.
• For power generation.
• Semi-bituminous coal : characters between
bituminous & anthracite, low VM & has Coking
property. CV =8400cal/gm, % C – 85%

22. Anthracite
• Composition : 92-98% C, very low VM, ash and
moisture
• Lustrous black & hard coal.
• Burns with non smoky short blue flame
• C.V. 8700 cal./gm.
Uses :
• High cost, for specific purpose
• For high temperature heating.
• As metallurgical fuel.
• Making electrodes

23. Analysis Of Coal
Purpose of coal analysis……….
✓ To decide price of coal
✓ To determine quality
✓To specify use of coal for a particular purpose
✓To calculate theoretical CV of coal
✓To calculate air requirement for complete
combustion and proper design of furnace

24. • Proximate Analysis : 1) % Moisture
2) % Volatile Matter
3) % Ash
4) % Fixed Carbon
Crucible

25. • Ultimate Analysis :
• %C, %H = by using CaCl2 U- tube &
KOH U- tube.
• %S = by adding BaCl2 into H2SO4 .
• %N = By using Kjeldahl’s method.
• % Ash = by proximate analysis
• %O = 100 - (%C + %H + %S + %N + % Ash)

26. Liquid Fuel: Petroleum Oil
Petroleum (Crude oil)
• An important primary liquid fuel.
• It is a dark greenish-brown viscous oil found deep in the
earth’s crust.
• It is formed millions of years ago by anaerobic decay of
of debris of plants and animals (which are buried due to
volcanoes) under the influence of high temp. & pressure.
• Organic debris convert into alkenes, which on
isomerisation, cyclisation form crude oil.

27. Liquid Fuel: Petroleum Oil
Porous rock
Composition of Oil : C = 80 – 87 %, H = 11 – 15 %, S = 0.1-
3 %, O = 0.1 - 0.9 %, N + 0.4 - 0.9 %
Petroleum oil contains- Open chain alkane, Cycloalkanes,
Aromatics, Asphaltenes and Resins.
Soil
Sand
Shale

28. Refining Of Petroleum
• It involves Three steps –
1) Removal of water : salty water removed from oil
by passing crude oil through highly charged
electrodes. The colloidal water droplets unite on
positive electrode to form large drops which
separate from oil.
2) Removal of Sulphur : Crude oil then treated with
CuO to remove Sulphur from Sulphur compounds in
crude oil
3) Fractionation : The principle of fractional
distillation is that the vapours of higher boiling point
compounds first get condensed into liquid, during the
stepwise cooling.

29. Refining Of Petroleum
Construction:
Tall cylindrical tower
made up of stainless steel,
30 m height & 3m
diameter, 50-60
horizontal SS tray's –half
meter distance, each tray
with 4-5 bubble cups with
loose caps – for rising
vapours through cups
bubble. Draw off plate, &
temp. 400 C to 40 C .

30. • The crude oil is heated at about 400°C in a furnace. Vapours
enter into the fractionating column at the bottom.
• The vapours travel upwards through the bubble cups and
gradually get cooled. The vapours of organic compounds
with higher B.P. get condensed in bubble cups and the liquid
deposits on the trays.
• The uncondensed vapours rise up and get condensed in
upper trays.
• From various trays, the fractions like petrol, diesel,
Kerosene, naphtha, heavy oil etc. are taken out. Finally a
small part of vapours comes out as uncondensed gases from
the top at about 40°C.
• Heavy oil fraction can be further fractionated to get
lubricating oils, Vaseline, wax. The petrol obtained from
refinery is called as straight run petrol but is not a good
quality petrol.
Working

31. Portion of Fractionating tower
Draw off plate
Condensate
Down spout
Vapours
Bubble Plate
Bubble Cup

32. Fractions Collected from crude Oil
Sr.N
o
Name of
fraction
Boiling
range
Composition Uses
1
Uncondens
ed Gases
> 40 C1 - C4 LPG Fuel for domestic
2
Petroleum
ether
40 - 70 C5 - C7
Fuel for Aeroplane,
Helicopters
3 Petrol 60 - 120 C5 - C8
Petrol engine, dry
cleaning
4 Naptha 120 - 180 C7 - C10 Solvent, dry cleaning
5 Kerocene 180 - 250 C10 - C16
Domestic fuel, oil gas,
jet engine
6 Diesel 250 - 320 C15 - C18 Diesel engine
7 Heavy Oil 320 - 400 C17 - C30
For making petrol by
cracking
8 Residue Aboce C30 Road making, fuel

33. Alternative Fuel: Power Alcohol
• When ethyl alcohol is used as fuel in internal
combustion engine, it is called as power alcohol.
• Manufacture of ethyl alcohol : Fermentation of
molasses, starch & carbohydrates.
• Advantages : i) good anti- knocking property & its
O.N is 90, petrol has O.N 65.
ii) Property to absorb traces of water from petrol.
iii) C.V is low – special engine design with high C.R
iv) ethanol contains ‘O’ – help for combustion.
v) Cheaper than petrol & save foreign currency.

34. Disadvantages
• Ethanol has C.V lower (7000 cal./gm.) than
petrol (11000 cal./gm.) so it reduces power
output up to 35%
• High surface tension – atomization is difficult
specially at Low Temperature.
• Undergo oxidation to form Acetic acid which
corrodes engine
• Obtained by fermentation can not be directly
mixed with petrol, it requires dehydration first.
• Contains ‘O’ atoms – air required is less –
required modification of carburetor & engine.

35. Biodiesel
• Biodiesel is biofuel obtained from renewable sources of
energy such as vegetable oils or animal fats by trans-
esterification reaction using sodium methoxide
catalyst.
• Trans-estrification is a process of converting one ester into
another ester.
• Vegetable oil such as soya bean oil, Palm oil, Cotton seed oil,
Sunflower oil, Peanut oil, Rapeseed oil etc.
Compounds present in biodiesel are like,
methyl palmitate H 3C - (CH2)14 - COOCH3
methyl stearate H3C - (CH2)16 - COOCH3
methyl oleate H3C - (CH2)7 - CH = CH - (CH2)7 - COOCH3
methyl linoleate H3C - (CH2)5 - (CH = CH)2 - (CH2)7 - COOCH3

36. Preparation reaction
CH2 – OOCR1 R1COOCH3 CH2OH
+
CH - OOCR2 +3 CH3OH R2COOCH3 + CHOH
+
CH2 - OOCR3 R3COOCH3 CH2OH
Products of Reaction are Biodiesel and glycerol
Why do They separate?
➢ As they are immiscible
phases, we can easily drain
off the glycerine and
biodiesel is left behind.
Biodiesel
Glycerine

37. Advantages
• Non- conventional, renewable energy source
obtained from domestic sources.
• High C.N 46 – 54 , high C.V.
• Higher flash point – safer for storage.
• Cheaper, regenerative & ecofriendly.
• Does not give toxic exhaust gases.
• Clean to use biodiesel in diesel engine
• Provide good market for vegetable oils &
reduces our dependence on foreign country.

38. Disadvantages
• May have dissolving action on rubber
hoses, gaskets.
• Shortage of vegetable oils & starting
material if costly, the biodiesel will be
costly.
• Biodiesel strongly adheres on metals &
can become gummy.

39. Gaseous fuel : Natural Gas
• Natural Gas : Composition
• Properties: i) Burns with non-smoky flame
• C.V 12000-14000 Kcal./m3
Applications:
• Domestic fuel
• To produce carbon black & hydrogen
• In making various petrochemicals
methanol, acetic acid, formic acid etc.
• To get sec. fuel CNG, LNG & LPG

40. • CNG: Composition
• Properties: i) higher ignition point than LNG,
LPG and petrol
• C V 13000 Kcal/m3
• Mixes better with air than liquid fuel
• Burns completely –no SOx, and Co emissions
• Uses: fuel for petrol, diesel engine
• Industrial and domestic fuel
• Source of carbon black, hydrogen
Gaseous fuel : CNG

41. • Composition : LPG mainly contains propane and
butanes along with little pentanes, hexanes.
• Properties :
1) LPG has C.V. about 25000 cal/lit.
2) To know the leakage of LPG from cylinder, a small amount of
organic sulphur compound is mixed in LPG. The mercaptan or
thioether has characteristic smell.
3) It burns with blue flame and it is clean to use.
• Uses : 1. LPG is used as domestic fuel, industrial fuel.
2. LPG is useful as motor fuel.
Liquefied Petroleum Gas

42. Hydrogen
• Chemical symbol H , atomic number 1. atomic weight :
1.00794 a.m.u, hydrogen is the lightest element and its
monatomic form is (H), 92 % of universe is made up of
hydrogen, It is the 10 th most abundant element found on
earth.
• At standard temperature and pressure, hydrogen is
a colorless, odorless, tasteless, nontoxic, nonmetallic,
highly combustible diatomic gas with the molecular
formula H2.
• Most of the hydrogen on Earth in molecules such as water
and organic compounds because hydrogen readily forms
covalent compounds with most non-metallic elements.
• Naturally occurring H contains 0.0156% by weight D & One
atom of T in 1017 atoms of H.

43. Feed (Sulphur
free NG)
Steam
reforming
H2 and CO
• 1. Steam Reforming of Hydrocarbon:
H2 Gas
Liquid CO2
Higher % H2
+ CO2
Steam Steam
Compression
and Cooling
8OO C
It is the process of reacting steam with
hydrocarbon in the presence of a catalyst at high
temperature to obtain Hydrogen and carbon oxide
FeO Cat. 370 C,
Shift Reaction.
H2 gas

44. Reaction Conditions
• Feed = Sulphur free Natural Gas ( Methane),
Naphtha, Petroleum fractions.
• Catalyst = Ni Or FeO (Reforming)
• Temperature = 800 C (Reforming), 370 C
(Shift reaction).
• Pressure = Lesser than 1 atmosphere.
• Reactions
• CH4 + H2O CO + 3H2
• Shift Reaction
• CO + H2O CO2 + H2
• Then Mixture is compressed & Cooled to get liquid CO2 & H2
gas.

45. 2. Coal & Steam Reaction.
• Coal on heating with superheated steam produces water
gas ( 700 C) which is then reacted with more steam to
produce additional hydrogen by shift reaction.
Reactions
C + H2O CO + H2 CO2 + 2H2
Each carbon producing 2H2
• H2 obtained in this process is less & associated with
impurity like H2S, SO2 etc. hence process is less
preferred.

46. 3.Thermal Decomposition of
Hydrocarbon
• Thermal cracking of natural gas or hydrocarbons of a
petroleum fraction at 800-9000C produces carbon black
and Hydrogen as byproduct. After removing other
gaseous impurities by scrubbing, a relatively lesser
purity hydrogen is obtained.
CnH2n + 2 n C + (2n+2) H2
Purification
• Hydrogen can be purified to higher extent by i)
liquefication process ii) diffusing H2 gas through thin
& low porous palladium films at 3000C. H2 dissociates
into atoms on palladium, diffuses through the film &
again the atoms recombine to form 99.9 % pure
hydrogen.

47. Difficulties In Storage & Transportation
• High pressure hydrogen storage in steel cylinder causes
decarburization & steel becomes brittle, result in
explosion.
• Hydrogen is the lightest gas because of its low Mol. Wt. 2
i.e. 22.4 lit. of Hydrogen at STP weighs only 2 gms.
• Ignition temperature is lowest & it is highly inflammable.
• It is very difficult to liquefy, as its B.P is very low (-252.6
C). Cooling technology & very high cost of cooling &
insulation is required for the liquid hydrogen.
• Hydrogen storage in the form of Metal hydride requires
long time & high temperature, & also for regeneration
requires high temperature.
Thus the high cost, high volume, high risk, refueling time &
efficiency of storage are the challenges of hydrogen storage and
in transportation.