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

Introduction Type of fuels Combustion Conclusion Fuels and Combustion

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

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

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 298.15K. λv at 298.15K = 2442.5kJ/kg. Fuels and combustion

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 1kcal/kg = 1.8B.T.U/lB. For gases; kcal/cubic meter. BTU/cubic feet. Relation 1kcal/cubic meter = 0.107BTU/IB. Fuels and combustion

Introduction Type of fuels Combustion Conclusion Fuels and combustion

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

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

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 0.85-0.87 0.89-0.95 0.88-0.98

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

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

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 0.03 - 0.07% Corrosion of burner tips and damage to materials /equipments at high temperatures Fuels and combustion

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

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

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) 0.89-0.95 0.88-0.98 0.85-0.87 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

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

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

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

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

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

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

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

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

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

Solid Fuels (Chemical Properties) Type of Fuels Solid Fuels (Chemical Properties) Ultimate analysis Typical ultimate analysis of coal (%) Fuels and combustion GCV (kCal/kg) 4000 5500

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

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

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

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

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

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

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

Introduction Type of fuels Combustion Conclusion Fuels and combustion

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

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

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

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

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 (%)

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

Introduction Type of fuels Combustion Conclusion Fuels and combustion

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

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