Presentation1

1. COMBUSTION

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

3. TYPES OF COMBUSTION • SPOTANOEUS COMBUSTION • RAPID COMBUSTION • COMPLETE COMBUSTION • INCOMPLETE COMBUSTION • EXPLOTION

4. 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

5. 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.

6. 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.

7. 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

8. 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

9. 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.

10. TYPES OF COMBUSTIble substances • COMBUSTIBLE • NON COMBUSTIBLE SUBSTANCES

11. COMBUSTIBLE SUBATANCES • SUBSTANCES WHICH CAN BURN ARE CALLED AS COMBUSTIBLE SUBSTANCES.

12. EXAMPLES OF COMBUSTIBLE SUBSTANCES COAL WOOD LOG

13. EXAMPLES OF NON COMBUSTIBLE SUBSTANCES WATER BRICK

14. NON COMBUSTIBLE SUBSTANCES • SUBSTANCES WHICH DO NOT BURN ARE CALLED NONCOMBUSTIBLE SUBSTANCES.

15. CONDITIONS NECESSARY FOR COMBUSTION

16. 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.