In this article, I will share factors that influence the size and shape of a furnace.
These factors are necessary to be observed for the furnace to work efficiently.
They are essential when it comes to designing, choosing a furnace for a power plant and even installing it.
If these factors I will share in this article are not met when designing and installing the furnace, the overall burning system will be faulty.
Without wasting time, let me share what you need to know.
These are the factors influencing the size and shape of a furnace;
1. The type of fuel that will be used.
The type of fuel used in the furnace is one of the factors that affect the size and shape of a furnace.
What you have to know is that the furnace used to burn coal is different from the one that will be used to burn oil.
Also, the furnace that will be used to burn pulverized coal won’t be similar to the one that is designed to burn coal that is not grinded.
The type of fuel to be used has a great influence on the size and shape of the furnace because it’s the first thing that is observed before a furnace is designed.
The furnace has to be designed according to the type of fuel that it will burn.
All the design considerations will ensure that the furnace will sufficiently burn the fuel without issues.
If the furnace requires the fuel to be pulverized, the furnace size and shape are going to differ to be able to accommodate the fuel.
You might like this: Pulverized Fuel Burner: Components, Types, Requirements and Working Principle and Advantages Of Using Pulverized Coal
When liquid fuels are to be used, the furnace has to be in a size and shape that will accommodate the liquid fuel without wasting it.
The furnace will be designed according to the type of fuel it will burn; this affects its size and shape.
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2. Type of firing method that will be used.
The firing method that will be used is also one of the factors that affect the overall design of a furnace.
Think about it, do you think a grate-fired furnace will have the same design as a chamber-fired furnace?
Grate fired furnace is designed to burn solid fuels; the big chunks of coal are fed into the furnaces and burning goes on without any problem.
When we talk about chambered-fired furnaces; it’s designed to burn pulverized coal.
The size and shape of a grate and chambered-fired furnace are going to vary because they are designed to burn fuel of different sizes and types.
For the fired chamber furnaces, the coal has to be grinded and then blown to the furnace.
The shape of this furnace will be designed to prevent wastage of the fuel by wind and spillage.
The size will also provide the quick movement of the fuel from one point to another.
The type of firing method to be used influences the size and shape of the furnace.
3. Amount of heat to be recovered from the furnace.
Heat recovery from the furnaces is very essential when it comes to minimizing heat losses.
You might like this: Type Of Heat Losses In a Steam Plant (+How To Minimize Them)
Every power plant has to ensure that heat recovery is done effectively to improve the efficiency of energy generation and save fuel.
All these are practices that will end up decreasing the running cost of the power plant thus increasing the profits.
The amount of heat to be recovered from a furnace has a great influence on its size and shape.
If the amount of heat to be recovered from the furnace needs to be higher; the size and shape of the furnace will be designed to make that happen.
The larger the furnace, the more the amount of heat can be recovered from the furnace.
In this case, the furnace’s size will have to be bigger and its shape will be designed to make it easier for the heat to be recovered.
If the amount of heat to be recovered from the furnace is less, then the size of the furnace will have to be smaller.
The smaller size of the furnace will save fuel and not much heat will be lost to the atmosphere through radiation.
The shape of the furnace will also be designed to minimize heat loss from the furnace since there is no higher amount of heat energy being recovered from the furnace.
4. Quantity and quality of the steam to be produced.
The process of steam generation in a steam power plant and boilers mainly depends on the heat energy from the furnace.
The furnace has the ability to either increase or decrease the overall efficiency of the steam power plant or boiler.
You might like this: Steam Power Plant: Introduction, Components And Working Principle
The amount of steam needed and its condition has a great influence on the size and shape of the furnace.
Let me explain how this happens; if the quality of the steam needed is to be higher, the size of the furnace will have to be bigger.
The bigger the furnace, the higher the amount of fuel it will burn thus producing the heat energy needed to generate the amount of steam needed.
But if the quantity of steam needed is less, it doesn’t make sense to design a bigger furnace.
A bigger furnace in this case will only result in a waste of fuel and a higher amount of heat energy will be lost.
The higher the amount of energy produced by the furnace, the higher the amount of steam will be produced.
The quality of the steam will also be improved because of the amount of heat energy produced by the furnace.
And that is why you will never find a smaller boiler with a bigger furnace and vice versa.
The amount of steam needed and its condition is one of the factors that influence the size and shape of the furnace.
5. Pressure and temperature desired.
The pressure and temperature desired from the furnace is another factor that influences the size and shape of the furnace.
I have no idea how I should frame this for you to understand what I mean when it comes to the pressure and temperature desired from the furnace.
Let us take it this way; when the temperature of a system increases so will the pressure.
If the size of the furnace is bigger, it will accommodate more fuel thus the heat energy produced will be higher.
This also means that the pressure of the flame will be higher with the increase in temperature.
This perspective is from Gay Lussac’s law.
By increasing the size of the furnace you will increase the temperature of the flame thus increasing the pressure.
That is how I can best explain this factor and how it affects the size and shape of the furnace.
The shape of the furnace affects the flame temperature by the way air will be circulated within it.
Both size and shape play a big role when it comes to the amount of heat energy to be produced from the furnace.
6. Grate area required for the furnace.
This is pretty explainable. If you want the grate area of the furnace to be bigger you will have to increase the size of the furnace.
On the other hand, if the area of the grate of the furnace has to be small, the reduction of the size of the furnace will do the trick.
If the size of the power plant is small, the size of the furnace will have to be decreased to give room for more components to be installed.
This will force the size of the furnace to be smaller.
But if the space is bigger and the boiler unit is huge, a furnace with a large grate area will be needed.
The size of the furnace will have to be bigger.
I hope that sunk in.
7. Ash fusion temperature of the furnace.
Ash fusion may sound so strange and a complicated term to understand.
You may be wondering how it relates to a furnace. Ash fusion temperature is the measure of the temperature at which the ash will start melting forming a liquid.
The temperature of the furnace affects when the ash fusion happens.
In most cases; if the furnace ash fusion temperature is around 12000C to 16000C, when the furnace reaches these temperatures the ash from the furnace should have already been removed to prevent the ash fusion.
The ash fusion is what will lead to the formation of clinkers on the furnace which will corrode the furnace.
I know you are wondering how this is related to the size and shape of the furnace.
It’s pretty simple, the bigger the furnace, the more heat it will generate.
If the ash fusion temperature is lower the size of the furnace will have to be reduced or if the furnace will be bigger, efficient cooling of the furnace should be provided.
Reducing the size of the furnace decreases the overall temperature of the furnace thus preventing ash fusion at lower temperatures.
All this issue of ash fusion temperature mainly depends on the temperature of the furnace and the type of fuel used.
This is because we have ashes with lower and higher melting points.
And that is where the size and shape of the furnace come in.
Now I know you have an idea of how the size and shape affect the ash fusion temperature of the furnace.
8. The flame length required from the furnace.
The flame length required from the furnace is also one of the factors that affect the size and shape of the furnace.
Controlling the amount of air that enters the furnace can affect the flame length.
If the furnace is bigger, it can allow more in thus increasing the flame length, which is the first theory.
The size and shape affect the flame length of the flame produced by the furnace.
The length of the flame is affected by the amount of air and fuel mixture.
The second theory is that; if the fuel and air mixture ratio is not balanced, this will end up affecting the flame length.
The size and shape of the furnace have a huge influence on the amount of fuel and air that the furnace will hold.
So, it has an influence on the flame length required from the furnace.
9. Amount of excess air needed.
The amount of excess air needed in the furnace has an influence on the size and shape of the furnace.
The bigger the size of the furnace, the more air it will take in and vice versa is true.
So, if the amount of excess air needed in the furnace is more the size of the furnace will have to be bigger.
But if the amount of excess air needed is smaller, then the size of the furnace should be smaller.
The shape of the furnace should make it easier for the air to circulate freely in the furnace.
And that is how the amount of excess air needed in the furnace influences the shape and size of the furnace.
Lastly…
The size and shape of the furnace play a big role in the efficiency of the furnace.
There is a need for these factors to be closely observed to ensure that the furnace is operating at the required efficiency.
The size and shape of the furnace are sensitive issues that can affect the amount of air and fuel contained in the furnace.
Bigger furnaces are better for bigger power plants since they provide large amounts of heat energy once they are fully lit.
The problem is that they take longer to start up compared to small furnaces.
Smaller furnaces are appropriate for domestic installation and industries with small boiler units.
Thanks for reading, if you have any question you should leave your comment. See you in my next article.
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