Combustion & Flame
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Transcript of Combustion & Flame
Combustion & Flame
By
Vishnu M Nair
Index• Basic needs• How to extinguish Fire• The Ignition temperature• Inflammable combustion• Rapid & Spontaneous Combustion• Zones Of Candle Flame• Explosion• Fuel• Fuel Efficiency• Global Warming• Acid Rain
BASIC NEEDS
Basic Needs
The major conditions for a fire to burn is1. The presence of Oxygen2. The presence of fuel3. The temperature to reach flash point
Combustion – A chemical process in which a substance reacts with oxygen to give off heat is called combustion.
Basics of Combustion and Flame
We now understand that fire be seen with the help of the above
Q1. What will you do if you see a uncontrolled fire?
How to extinguish fire?
The answer to that question is so simple. Fire can only burn with presence of oxygen and
fuel and if temperature is above flash point.So to extinguish fire remove away any of these
For Example1. By denying the access of oxygen Example: If fire is on a human body we should
cover him tightly with a blanket like that on the picture below
2. By taking away the fuel 3. By decreasing the temperature below flash
pointThis can be done by poring water over the fire
Q. What will you do if the fire is caused by an electric short circuit
In such a case DO NOT TRY TO EXTINGUISH IT WITH WATER.
As water may come in contact with electric shock which could lead to serious injuries or even DEATH
The Ignition Temperature
The lowest temperature at which a substance
catches fire is called its Ignition TemperatureIt is essential for a substance to reach its ignition
temperature to burn
Given here are some fuels and its ignition temperature
Sl no. Fuel Temperature
1 Diesel 210 degrees2 Petrol 246 degrees3 Butane 405 degrees4 Paper 450 degrees5 Magnesium 473 degrees6 Hydrogen 536 degrees7 Triethylborane -20 degrees
Inflammable substance
The Substances which have very low ignition temperature and can easily catch fire with a flame are called inflammable substances
Some examples are: Petrol, Alcohol, Liquid Petroleum Gas
RAPID COMBUSTION AND SPONTANEOUS COMBUSTION
Rapid Combustion and Spontaneous Combustion
Rapid Combustion: Gas burns rapidly and produces heat and light. Such combustion is known as rapid combustion.
Rapid Combustion and Spontaneous Combustion
Spontaneous Combustion: The type of combustion in which a material suddenly bursts into flames, without the application of any apparent cause is called Spontaneous Combustion
Zones of Candle Flame
Explosion
When a cracker is ignited, a sudden reaction takes place with the evolution of heat, light and sound. A large amount of gas formed in the reaction is liberated. Such a reaction is called explosion.
Fuel
The substance that undergoes combustion is said to be combustible or FUEL
Fuel
Liquid
Solid
Gas
Know more on fuels
A Good Fuel – A good fuel is:-• Readily Available• Cheap• Burns easily in air• And does not leave any undesirable substance
behind.
Fuel Efficiency
The amount of heat produced on complete combustion of 1 kg fuel is called its calorific value. The calorific value is expressed in a unit called kilojoules per kg (kj/kg).
Fuel Calorific Value
Cow dung cake 6000-8000
Wood 17000-22000
Coal 25000-33000
Petrol 45000
Kerosene 45000
Diesel 45000
Methane 50000
LPG 55000
Biogas 35000-40000
Hydrogen 150000
BURNING OF FUELS LEADS TO HARMFUL PRODUCTS
Global Warming
Combustion of most fuels releases carbon dioxide in environment. Increased carbon dioxide in air is believed to cause global warming
A bear that lost his home because of ice melting
Acid Rain
Burning of coal and diesels releases sulphur dioxide gas. Oxides of sulphur and nitrogen dissolve in rain water and forms acids.
Such a rain is called acid rain.
Acid rain
THE END
DONE BYVISHNU
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