In this article, I will share the conditions that should be met to facilitate proper combustion of the fuel.
For the fuel to undergo complete combustion, some measures should be put into place.
What I am going to share with you in this article, isn’t very different from what I talked about when I was writing about the factors affecting combustion efficiency of the fuels.
You might like this: Factors Affecting Combustion Efficiency Of Fuels
Without wasting time, let me share the conditions that will facilitate the complete combustion of the fuel in the furnace.
These are the conditions that facilitate the proper burning of the fuel;
1. Correct mixing and ratio of air and fuel.
For the fuel to properly burn the mixing of the air and fuel should be in the correct ratio.
You have to know that for the combustion to happen progressively the distribution of air in the fuel should be uniform.
That is when the combustion will be complete without any problems.
So, for proper burning to happen, a balance of the air and fuel mixture should be observed.
Too high or too low air-fuel ratio will bring about problems in the combustion chamber.
The excess air-fuel ratio will decrease the temperature of the flame; it will bring about high consumption of the fuel and dilute the gasses used in combustion.
While low air-fuel ratio will lead to low combustion efficiency since the flame that will be produced will have high smoke content and exhaust gas.
The combustion will be incomplete.
For one to ensure that this condition is met, proper tuning of the burner should be done frequently to ensure that mixing is appropriate.
If the fuel is in the furnace, it has to be mixed by any mechanism to make sure that the air that enters the furnace is correctly mixed with the fuel.
2. Sufficient time for the fuel to burn in the furnace.
This is another important condition that should be met to ensure that proper combustion is achieved.
We have different types of firing systems that are used in different plant setups.
There are those who prefer using the pulverized system, chain grate stoker and the burners such as the oil rotatory cup burner.
You might like this: Overfeed & Underfeed Stokers: Classification and Working Principles
The fuel is supposed to be fed into the furnace to burn and then the ash is to be disposed of to allow another new volume of fuel to be fed into the furnace.
Some firing systems will have an automatic feeding mechanism where the fuel is fed to the furnace and the ash is disposed of timely.
A good example is the chain grate stoker; the chain keeps rotating as the fuel is being fed on top of it.
Remember when the chain reaches the end of the roller, disposal of the ash that was left on the top of the chain should happen.
So, if the chain is moving faster compared to the amount of time that is allowed for the fuel to completely burn, most of the fuel will be disposed of in the ash pit instead of the ash.
The fuel needs enough time to be able to burn completely before it reaches the end of the roller.
That is what will facilitate complete combustion because the fuel will have enough time in the furnace.
The chain should move slowly, to allow the fuel to have enough time in the furnace to burn completely and the feeding mechanism should also be adjusted as per the speed of the chain.
The more time the fuel has on the furnace, the sufficiently it will burn.
3. Flame of high temperature.
The flame should have a high temperature to facilitate proper burning of the fuel.
This is another condition that should be met if complete combustion is needed.
The high temperature of the flame allows the vaporized fuel molecules to decompose in the air, which will allow other incomplete combustion to keep on happening within the flame.
This will ensure that the fuel is burnt completely and no fuel is left to escape to the atmosphere.
The high temperature of the flame will ensure that the fuel that is vaporized is also burnt completely before it leaves the furnace.
This will result in proper combustion thus high energy is produced by the flame.
These are some of the measures that can be put into place to ensure a flame of high temperature is produced;
- One should use pure oxygen in combustion rather than the free air from the atmosphere.
- There should be a correct amount of oxygen to complete the combustion; it should not be too excess or too little just balanced.
- The radiation of the heat to the surrounding should be minimized to ensure a flame of high temperature is produced.
The low flame temperature will lead to incomplete combustion since the vaporized fuel won’t be burnt completely.
The combustion will be of low quality thus producing a lower amount of energy.
4. Turbulent mixing of fuel and air.
Turbulent mixing of fuel and air ensures that there is proper mixing of the fuel and air which ends up in facilitate proper burning.
Turbulent mixing involves mixing due to the turbulent flow, which allows the air to reach every molecule of the fuel in the furnace thus facilitating proper combustion.
Most firing systems used usually have mechanisms that facilitate proper turbulence.
Proper turbulence is what will allow stable combustion in the furnace thus producing a quality flame.
A good example of a firing system that provides excellent turbulence is the turbulent pulverized fuel burner.
Due to the amazing turbulence it offers, this ensures that the burner produces a very hot flame compared to the rest of the burner.
You might like this: Pulverized Fuel Burner: Components, Types, Requirements and Working Principle
In some cases where a firing system doesn’t have proper turbulence, the introduction of three-dimensional flows may be introduced.
The air enters the combustion chamber in different parts while the fuel also enters in another part, this will create a turbulent that will result in complete combustion.
5. Correct proportioning of the furnace dimensions.
Correct proportioning of the furnace dimensions is another condition that facilitates proper combustion.
Think about it, the furnace is what holds the fuel to be burned, if the dimensions are not correctly proportioned, this means that the air distribution will also be affected.
When this happens, the air-fuel ratio in these proportions will not be correct and this will end up producing a flame of poor quality.
Also, if there is a large amount of fuel in a certain space of the furnace since the dimensions were done wrongly, this will affect the air circulation in the fuel thus affecting the combustion also.
The proportions of the furnace should be done accordingly keeping in mind the amount of fuel that will be fed in each section.
You have to know that the furnace efficiency is affected by the design and dimensioning.
Lastly…
If these conditions are put into place, proper combustion will be achieved despite the challenges.
Proper burning is necessary to provide high operating efficiency of the fuel, reduce accidents caused by carbon monoxide, allow maximum use of the fuel and produce the needed energy value to keep the plant processes going on.
With proper combustion, the fireside maintenance is going to significantly decrease and this will end up decreasing the operation cost of the power plant.
So, there is every need to ensure that these conditions are put into place if one wants all these benefits.
Thanks for reading, if you have any questions just let me know in the comment section. See you in my next article.
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