What is Combustion?
In simple terms, Combustion is the process of burning. It is a chemical reaction in which the fuel or the substance reacts with an oxidant or oxygen to produce heat. For instance, the burning of petrol or diesel in a vehicle, burning natural gas on the stovetop, burning wood for cooking or in a fireplace, etc can all be considered as combustion.
Combustible Substances
Substances that can burn with the help of oxygen are called combustible substances. Heat and light are given away during the process of combustion. It is also known as fuel. Fuel can be in either a solid, liquid, or gas state.
Inflammable Substances
Substances that catch fire easily or which have low ignition temperature are called inflammable substances.
Non-Combustible Substances
Substances that cannot burn with the help of oxygen are called non-combustible substances.
Combustible substances have a required combustion temperature to burn or catch fire which varies for different substances.
Conditions for Combustion
Combustion has mainly three requirements, namely, fuel, air, and ignition temperature.
Combustion can only take place when there is a fuel or a substance that can catch fire and release heat and light as a result.
The process of combustion will take place only when there is a presence of air. Combustion would not take place when practised in a closed space without air.
Ignition temperature is the temperature at which the fuel catches fire for burning. If the temperature is lower than the ignition temperature of that specific fuel, it will not burn.
Common Examples of Combustion
Some of the common examples of combustion are listed below:
Burning of wood.
Burning of a candle.
Burning of natural gas on the stovetop.
Burning of sulfur.
Explosion of Hydrogen in air.
Types of Combustion
There are mainly three types of combustion.
1. Complete Combustion
Complete combustion is the process in which the fuel is allowed to react with an oxidant with an unlimited supply of air. This ends up in the complete burning of the substance and as a result, a byproduct is also produced. Carbon dioxide and water are produced. For example, when we burn wood using fire, if it is allowed to burn until ashes are produced, it is a complete combustion process.
2. Incomplete Combustion
In incomplete combustion, when the fuel is not provided with adequate oxygen, it will not burn completely. So the by-products of carbon dioxide and water are not produced.
3. Rapid Combustion
Rapid combustion is the type in which the fuel or the substance catch fire rapidly. For instance, when we bring a lighted match stick or candle near a gas stove which is turned on, it will catch fire very quickly. As a result, heat and light are produced.
1. Spontaneous Combustion
In this type of combustion, the substance catches fire abruptly without a known cause and it tends to spread easily too. For example, a forest fire is caused by the rubbing of dried tree trunks or a spark caused by unknown sources that create wild and uncontrollable fire.
2. Explosion Combustion
In this type of combustion, a quick blast of fire, light, heat, and sound is produced. For example, when a cracker is lighted, it blasts with light, sound, fire, and sound. And it releases a high amount of gas as well.
Combustion Fuel
Combustion fuels are the substances that are used to cause fire or to cause combustion. Combustion fuels are in solid, liquid, and gas forms.
Important combustion fuels used worldwide are Petrol, Diesel, coal, oil, LPG, Gasoline, wood, etc. Each of these combustion fuels has its characteristic features when it comes to the reaction. When the quantity of carbon in the fuel is increased, more air is required for the complete combustion of the substance.
Liquid Combustion Fuel
Liquid combustion fuel is combustion in which the fuel is in liquid form. It doesn't have a specific shape but takes the shape of the vessel it contains. Examples of liquid combustion fuels are petrol, diesel, kerosene, etc.
Gaseous Combustion Fuel
Gaseous combustion fuels are combustion fuels which are in gaseous form. For example, LPG. Gaseous combustion fuel is a comparatively more dangerous and uncontrollable form of combustion fuel.
Solid Combustion Fuel
Solid combustion fuel is the combustion in which the fuel is in solid form. Examples of solid combustion fuel are coal, wood, etc.
FAQs on Combustion Fuel
Q1. How to Stop Combustion?
To stop combustion, one of the elements from the fire triangle should be removed. The fire triangle consists of fuel, heat, and oxygen. Fuel is the main factor and when the combustion runs out of fuel, the process stops, and fire can be put down. When heat is removed, the process cools down. When oxygen is removed, combustion won't take place. Because the process of combustion requires oxygen. If the fire is caused by fuel such as wood or fabric, it can be put down by the water. If the fire is caused by agents such as gas, petrol, or diesel, it can be put down by using foam extinguishers. Any powder extinguisher such as carbon dioxide powder is advised to use. To stop fire caused by metal, powder extinguishers can be used.
Q2. Can Combustion Take Place without the Presence of Oxygen and What Kind of Reaction is Combustion?
When a substance of comparatively low ignition emits heat, spontaneous combustion occurs and flames. When provided with sufficient oxidant or oxygen process of combustion takes place. Oxygen or oxidant is an important element for combustion. When there is a sufficient amount of oxygen for combustion, the complete composition takes place, and as a result, carbon dioxide and water are produced. When there isn't enough oxygen for the combustion, incomplete combustion takes place, and less or no by-products are produced. Combustion is a chemical reaction in which a substance or a fuel emits energy in the form of light, heat, and sometimes sound as well. For this process, the presence of oxygen is very important. As a by-product of the process, water and carbon dioxide are produced.
