1. A PRESENTATION ON: FUels & Combustion SUBMITTED TO: SUBMITTED BY:
Prof. VASANTHAKUMAR PAI SIR
Dept.of
INDUSTRIAL CHEMISTRY
KUVEMPU UNIVERSITY,
SUBMITTED BY:
ASHA.E
3rd SEMESTER,
INDUSTRIAL CHEMISTRY
KUVEMPU UNIVERSITY

2. Introduction
Type of fuels
Combustion
Conclusion
Fuels and Combustion

3. Introduction The Formation of Fuels Fuels and combustion
Solar energy is converted to chemical energy through photo-synthesis in plants
Energy produced by burning wood or fossil fuels
Fossil fuels: coal, oil and natural gas
Fuels and combustion

4. CLASIFICATION OF FUELS
CHEMICAL FUELS
SECONDARY OR DERIVED FUELS
PRIMARY OR NATURAL FUELS
SOLID:
Wood,coal, lignite
SOLID: coke,charcaol,petroleum
LIQUID:
Petrol,kerosene,diesel.
GASEOUS:coal gas, water gas, biogas
LIQUID:
Crude oil
GASEOUS:
Natural gas

5. Introduction Fuels and combustion Calorific value
Calorific value is the total quantity of heat liberated when a unit mass of fuel burn completely.
Measured at 25˚C.
Heat or energy produced
Gross calorific value (GCV): vapour is fully condensed
Net calorific value (NCV): water is not fully condensed.
NCV = GCV – (mass %hydrogen)(9)(λv)kJ/kg
λv –latent heat of water vapour at reference temperature, normally at K.
λv at K = kJ/kg.
Fuels and combustion

6. Units of calorific values:
Introduction
Units of calorific values:
For solid and liquid calorific value are
Joules/kg [ in SI system]
calori / gram [ in cgs system]
kcalori/kg [ in mks system]
B.T.U/lB [ British system ]
Relation kcal/kg = 1.8B.T.U/lB.
For gases; kcal/cubic meter.
BTU/cubic feet.
Relation kcal/cubic meter = 0.107BTU/IB.
Fuels and combustion

7. Introduction
Type of fuels
Combustion
Conclusion
Fuels and combustion

8. Type of Fuels Liquid Fuels Usage Fuels and combustion Examples
Used extensively in industrial applications
Examples
Furnace oil
Light diesel oil
Petrol
Kerosine
Ethanol
LSHS (low sulphur heavy stock)
Fuels and combustion

9. Type of Fuels Liquid Fuels Density Fuels and combustion
Ratio of the fuel’s mass to its volume at 15 oC,
kg/m3
Useful for determining fuel quantity and quality
Fuels and combustion

10. Type of Fuels Liquid Fuels Specific gravity Fuels and combustion
Ratio of weight of oil volume to weight of same water volume at a given temperature
Specific gravity of water is 1 at 4˚C.
Hydrometer used to measure
Fuels and combustion
Table 1. Specific gravity of various fuel oils
Fuel oil type
LDO
(Light Diesel Oil)
Furnace oil
LSHS (Low Sulphur
Heavy Stock)
Specific Gravity

11. Type of Fuels Liquid Fuels Viscosity Fuels and combustion Flash point
Measure of fuel’s internal resistance to flow
Most important characteristic for storage and use
Decreases as temperature increases
Flash point
Lowest temperature at which a fuel can be heated so that the vapour gives off flashes when an open flame is passes over it
Flash point of furnace oil: 66oC
Fuels and combustion

12. Type of Fuels Liquid Fuels Pour point Fuels and combustion
Lowest temperature at which fuel will flow
Indication of temperature at which fuel can be pumped
Specific heat
kCal needed to raise temperature of 1 kg oil by 1oC (kcal/kgoC)
Indicates how much steam/electricity it takes to heat oil to a desired temperature
Fuels and combustion

13. Type of Fuels Liquid Fuels Sulphur content Fuels and combustion
Depends on source of crude oil and less on the refining process
Furnace oil: 2-4 % sulphur
Sulphuric acid causes corrosion
Ash content
Inorganic material in fuel
Typically %
Corrosion of burner tips and damage to materials /equipments at high temperatures
Fuels and combustion

14. Type of Fuels Liquid Fuels Carbon residue Fuels and combustion
Tendency of oil to deposit a carbonaceous solid residue on a hot surface
Residual oil: >1% carbon residue
Water content
Normally low in furnace oil supplied (<1% at refinery)
Free or emulsified form
Can damage furnace surface and impact flame
Fuels and combustion

15. Type of Fuels Liquid Fuels Calorific value: Fuels and combustion
Typical GCVs of some of the commonly used liquid fuels are given below:
Fuels and combustion
Fuel Oil Gross Calorific Value (kCal/kg)
Kerosene 11,100
Diesel Oil 10,800
L.D.O 10,700
Furnace Oil 10,500
LSHS 10,600

16. Type of Fuels Liquid Fuels Fuels and combustion
Typical specifications of fuel oils
Properties
Fuel Oils
Furnace Oil
L.S.H.S
L.D.O
Density (Approx. g/cc at 150C)
Flash Point (0C) 66 93
Pour Point (0C) 20 72 18
G.C.V. (Kcal/kg)
10500
10600
10700
Sediment, % Wt. Max.
0.25
0.1
Sulphur Total, % Wt. Max.
< 4.0
< 0.5
< 1.8
Water Content, % Vol. Max.
1.0
Ash % Wt. Max.
0.02
Fuels and combustion

17. Type of Fuels Liquid Fuels Storage of fuels Fuels and combustion
Store in cylindrical tanks above or below the ground
Recommended storage: >10 days of normal consumption
Cleaning at regular intervals
Fuels and combustion

18. coal Type of Fuels Solid Fuels DEFINITION Fuels and combustion
Coal is a highly homogeneous matter.
Coal is the most important fossil fuel.
In india, most of the calories are
situated in madhya pradesh,West Bengal,
Bihar and the bangs of river Godavari.
Fuels and combustion

19. Type of Fuels Solid Fuels Coal classification Fuels and combustion
Anthracite: hard and geologically the oldest
Bituminous
Lignite: soft coal and the youngest
Further classification: semi- anthracite, semi-bituminous, and sub-bituminous
Fuels and combustion

20. Type of Fuels Solid Fuels Physical properties Fuels and combustion
Heating or calorific value (GCV)
Moisture content
Volatile matter
Ash
Chemical properties
Chemical constituents: carbon, hydrogen, oxygen, sulphur
Fuels and combustion

21. Solid Fuels (Physical properties)
Type of Fuels
Solid Fuels (Physical properties)
Heating or calorific value
The typical GVCs for various coals are:
Fuels and combustion
Parameter
Lignite
(Dry Basis)
Indian Coal
Indonesian Coal
South African Coal
GCV (kCal/kg)
4,500
4,000
5,500
6,000

22. Solid Fuels (Physical properties)
Type of Fuels
Solid Fuels (Physical properties)
Moisture content
% of moisture in fuel (0.5 – 10%)
Reduces heating value of fuel
Weight loss from heated and then cooled powdered raw coal
Volatile matter
Methane, hydrocarbons, hydrogen, CO, other
Typically 25-35%
Easy ignition with high volatile matter
Weight loss from heated then cooled crushed coal
Fuels and combustion

23. Solid Fuels (Physical properties)
Type of Fuels
Solid Fuels (Physical properties)
Ash
Impurity that will not burn (5-40%)
Important for design of furnace
Ash = residue after combustion
Fixed carbon
Fixed carbon = 100 – (moisture + volatile matter + ash)
Carbon + hydrogen, oxygen, sulphur, nitrogen residues
Heat generator during combustion
Fuels and combustion

24. Solid Fuels (Physical properties)
Type of Fuels
Solid Fuels (Physical properties)
Proximate analysis of coal
Determines only fixed carbon, volatile matter, moisture and ash
Useful to find out heating value (GCV)
Simple analysis equipment
Ultimate analysis of coal
Determines all coal component elements: carbon, hydrogen, oxygen, sulphur, other
Useful for furnace design (e.g flame temperature, flue duct design)
Laboratory analysis
Fuels and combustion

25. Solid Fuels (Physical properties)
Type of Fuels
Solid Fuels (Physical properties)
Proximate analysis
Typical proximate analysis of various coals (%)
Fuels and combustion
Indian Coal
Indonesian Coal
South African Coal
Moisture
5.98
9.43
8.5
Ash
38.63
13.99 17
Volatile matter
20.70
29.79
23.28
Fixed Carbon
34.69
46.79
51.22

26. Solid Fuels (Chemical Properties)
Type of Fuels
Solid Fuels (Chemical Properties)
Ultimate analysis
Typical ultimate analysis of coal (%)
Fuels and combustion
GCV (kCal/kg)

27. Solid Fuels (Chemical Properties)
Type of Fuels
Solid Fuels (Chemical Properties)
Storage, Handling & Preparation
Storage to minimize carpet loss and loss due to spontaneous combustion
Reduce carpet loss: a) a hard surface b) standard concrete/brick storage bays
Coal preparation before use is important for good combustion
Fuels and combustion

28. Type of Fuels Gaseous Fuels Advantages of gaseous fuels
Least amount of handling
Simplest burners systems
Burner systems require least maintenance
Environmental benefits: lowest GHG and other emissions
Fuels and combustion

29. Type of Fuels Gaseous Fuels Classification of gaseous fuels
(A) Fuels naturally found in nature
Natural gas
Methane from coal mines
(B) Fuel gases made from solid fuel
Gases derived from coal
Gases derived from waste and biomass
From other industrial processes
(C) Gases made from petroleum
Liquefied Petroleum gas (LPG)
Refinery gases
Gases from oil gasification
(D) Gases from some fermentation
Fuels and combustion

30. Type of Fuels Gaseous Fuels Calorific value Fuels and combustion
Fuel should be compared based on the net calorific value (NCV), especially natural gas
Fuels and combustion
Typical physical and chemical properties of various gaseous fuels
Fuel Gas
Relative Density
Higher Heating Value kCal/Nm3
Air/Fuel ratio m3/m3
Flame Temp oC
Flame speed m/s
Natural Gas
0.6
9350 10
1954
0.290
Propane
1.52
22200 25
1967
0.460
Butane
1.96
28500 32
1973
0.870

31. Type of Fuels Gaseous Fuels Liquefied Petroleum Gas (LPG)
Propane, butane and unsaturates, lighter C2 and heavier C5 fractions
Hydrocarbons are gaseous at atmospheric pressure but can be condensed to liquid state
LPG vapour is denser than air: leaking gases can flow long distances from the source
Fuels and combustion

32. Type of Fuels Gaseous Fuels Natural gas Fuels and combustion
Methane: 95%
Remaing 5%: ethane, propane, butane, pentane, nitrogen, carbon dioxide, other gases
High calorific value fuel
Does not require storage facilities
No sulphur
Mixes readily with air without producing smoke or soot
Fuels and combustion

33. Type of Fuels Comparing Fuels Fuels and combustion Fuel Oil Coal
Natural Gas
Carbon 84
41.11 74
Hydrogen 12
2.76 25
Sulphur 3
0.41 -
Oxygen 1
9.89
Trace
Nitrogen
1.22
0.75
Ash
38.63
Water
5.98
Fuels and combustion

34. Introduction
Type of fuels
Combustion
Conclusion
Fuels and combustion

35. Principles of Combustion
Combustion: rapid oxidation of a fuel
Complete combustion: total oxidation of fuel (adequate supply of oxygen needed)
Air: 20.9% oxygen, 79% nitrogen and other
Nitrogen: (a) reduces the combustion efficiency (b) forms NOx at high temperatures
Carbon forms (a) CO2 (b) CO resulting in less heat production
Fuels and combustion

36. Principles of Combustion
Control the 3 Ts to optimize combustion:
Water vapor is a by-product of burning fuel that contains hydrogen and this robs heat from the flue gases
Fuels and combustion
1T) Temperature
2T) Turbulence
3T) Time

37. Principle of Combustion
Oxygen is the key to combustion
Fuels and combustion

38. Stochiometric calculation of air required
Combustion
Stochiometric calculation of air required
Stochiometric air needed for combustion of furnace oil
Theoretical CO2 content in the flue gases
Actual CO2 content and % excess air
Constituents of flue gas with excess air
Theoretical CO2 and O2 in dry flue gas by volume
Fuels and combustion

39. Combustion Concept of Excess Air Fuels and combustion
Measure CO2 in flue gases to estimate excess air level and stack losses
Fuels and combustion
Excess air (%)
Carbon dioxide (%)

40. Combustion Concept of Excess Air Fuels and combustion
Measure O2 in flue gases to estimate excess air level and stack losses
Residual oxygen (%)
Excess air (%)
Fuels and combustion

41. Introduction
Type of fuels
Combustion
Conclusion
Fuels and combustion

42. CONCLUSION Fuels and combustion FUELS:
A combustible substance, containing carbon as main constituent which on proper burning, it gives amount of heat which can be used for domestic and industrial purposes. example: wood,cal,etc.,
COMBUSTION:
Combustion is an unit processin which oxidation reaction takes place.
The union of carbon,hydrogen, and sulphur with oxygen.
During combustion of a fuel, the atoms of carbon , hydrogen,etc., combine with the oxygen and liberates heat at a rapid rate.
Fuels and combustion

43. QUESTIONS?????? Fuels & Combustion Thank you for your attention!