COMBUSTION

WHAT IS COMBUSTION ?

A CHEMICAL PROCESS IN WHICH A SUBSTANCE REACTS WITH THE OXYGEN OF AIR TO GIVE HEAT & LIGHT IS CALLED COMBUSTION.

TYPES OF COMBUSTION

• SPOTANOEUS COMBUSTION• RAPID COMBUSTION• COMPLETE COMBUSTION• INCOMPLETE COMBUSTION• EXPLOTION

RAPID COMBUSTION

• Combustion in which a substance burns rapidly and produces heat and flame is known as rapid combustion, such as combustion of natural gas, LPG, petrol etc. • This is usually attained by introducing external heat. • Substances which undergo rapid combustion have lower ignition temperature

SPOTANOEUS COMBUSTION

• When a substance suddenly starts burning into a flame; without the supply of any external cause such as heating; the combustion is called spontaneous combustion.• Substances; which have relatively low temperature of ignition generally burn by spontaneous combustion.

COMPLETE COMBUSTION

• A reaction or process which entails only partial burning of a fuel. • This may be due to a lack of oxygen or low temperature, preventing the complete chemical reaction.

INCOMPLETE COMBUSTION• A reaction or process which entails only partial burning of a fuel. • This may be due to a lack of oxygen or low temperature, preventing the complete chemical reaction.• Carbon monoxide is produced as a by product from incomplete combustion

EXPLOSION• When combustion is accompanied by sudden production of heat, sound and large amount of gas, it is called explosion.• Firecrackers and bombs are substances which show explosion

EXAMPLES• Phosphorous and sulphur start burning instantaneously; at room temperature.• Haystacks, linseed oil, coal, pyrite, etc. sometimes start burning suddenly with flame because of increase in temperature.• In coal mines, fire breaks out many a times because of combustion of coal dust.• Fire often breaks out suddenly because of increase in temperature due to sun or friction.

TYPES OF COMBUSTIBLE SUBSTANCES

•COMBUSTIBLE •NON COMBUSTIBLE SUBSTANCES

COMBUSTIBLE SUBATANCES

• SUBSTANCES WHICH CAN BURN ARE CALLED AS COMBUSTIBLE SUBSTANCES.

EXAMPLES OF COMBUSTIBLE SUBSTANCES

COAL

WOOD LOG

EXAMPLES OF NON COMBUSTIBLE SUBSTANCES

WATER

BRICK

NON COMBUSTIBLE SUBSTANCES

• SUBSTANCES WHICH DO NOT BURN ARE CALLED NONCOMBUSTIBLE SUBSTANCES.

CONDITIONS NECESSARY FOR COMBUSTION

CONDITIONS NECESSARY FOR COMBUSTION

• PRESENCE OF THE COMBUSTIBLE SUBSTANCES ( A SUBSTANCE WHICH CAN BURN) • PRESENCE OF A SUPPORTER OF OXYGEN ( I.E. AIR) • HEATING THE COMBUSTIBLE SUBSTANCES TO ITS IGNITION TEMPERATURE.