An economizer is a heat exchanger that is used in a steam plant to recover heat that would otherwise be lost to the atmosphere.
It can be used to transfer heat energy from flue gasses to the combustion chamber of the boiler.
The economizer is a boiler accessory that is installed in the stack of the boiler.
Installing an economizer in a steam plant increases the efficiency of the boiler.
An economizer ensures that the heat is used to the maximum in the boiler and less heat is lost to the atmosphere.
Without forgetting another important function of the economizer; it reduces thermal stresses in the boiler because of the temperature differences.
You might like this: Type Of Heat Losses In a Steam Plant (+How To Minimize Them)
For the economizer to work effectively, there are several requirements that it should fulfil.
Without wasting time, let me share what you need to know about the requirements of an economizer.
Requirements Of Steam Plant Economizer
1. It should be compact.
This is one of the requirements that an economizer should fulfil. The economizer should be compact in size.
You may ask about the importance of an economizer being compact, this is what you should know; it should be compact in size to take up a small room in its installation.
Also, the economizer being compact is going to make it easier to fit in remote areas.
The other added advantage of the economizer being compact is that it’s going to be very easier to carry when it’s supposed to be removed from the boiler stack.
2. It should be easy to maintain.
An economizer should require cheaper maintenance and be easier to maintain.
As an accessory of a boiler, it should be easier to maintain so as to reduce downtime in any operations.
One should understand that the economizer plays a very important role in the steam plants.
If by any chance the economizer is damaged and it takes days to repair then much energy is going to be lost and this will end up decreasing the efficiency of the steam plant.
The ease of maintenance of the economizer will ensure that it’s always in use when it’s needed and keep the process in the steam plant effective.
It should be cheap to repair the economizer when there is a fault. We always aim at saving resources and getting the most out of the input we put into any power production process.
3. The tubes of the economizer should have high thermal conductivity.
This is another requirement that an economizer should fulfil. The tubes of the economizer should have high thermal conductivity because their main function is to transfer heat from one place to another.
If the tubes of the economizer will have lower thermal conductivity then this means that there will be no effective heat transfer to where it’s needed.
Much heat energy is going to be wasted by the flue gasses and emissions to the atmosphere will increase.
This means more fuel will be used but less productivity will be experienced since most of the energy is lost to the atmosphere.
So, the high thermal conductivity of the economizer tubes is very necessary for its efficiency.
4. The economizer tubes should be able to withstand the thermal stresses from the flue gasses.
The tubes of the economizer should withstand the thermal stresses from the flue gasses for the to transfer heat effectively.
This is another requirement that the economizer should meet.
The ability of these tubes to withstand the thermal stresses from the flue gasses is what will make the economizer effective.
There is much heat energy that the economizer will have to handle, if it will fail to withstand the thermal stresses and creep then the heat transfer is going to be limited.
So, here comes the design factor of the economizer and the type of materials that have been used to create the tubes.
5. It should not allow gasses to escape.
If the economizer allows flue gasses to escape the stack even without transferring the heat where it’s needed then it’s not going to be effective in the steam plant processes.
This is because so much energy would be lost to the atmosphere, more fuel will be wasted and thermal stresses in the boiler will be experienced.
The economizer should not allow flue gasses to escape to the atmosphere without the heat from the flue gasses being transferred where it’s needed.
Also, if the economizer has leakages, this means that the rate of heat transfer is going to be lower since more heat will be lost through the leakages.
6. The tubes should be long enough to increase the surface contact.
The heat transfer to be effective, there has to be sufficient contact between the flue gasses and the tubes.
The longer the flue gasses flow through the economizer tubes the more heat is transferred out of the flue gasses.
The coiling of the economizer tubes should be long enough to allow enough contact for heat transfer to be effective.
If the economizer tubes are long enough then this means the surface area of contact between the flue gasses and the tubes is going to increase and this will result in to increase in the efficiency of heat transfer.
More heat is recovered from the flue gasses and the efficiency of the steam plant increases.
Final thoughts.
These are some of the requirements that the steam plant economizer should fulfil to ensure that enough heat is recovered from the flue gasses.
If a steam plant economizer doesn’t meet these requirements then it’s going to be impossible to achieve efficiency in steam power plants.
You have to know that much heat energy is lost through the flue gasses, so recovering that is going to save fuel and enhance the efficiency of the boiler.
There are still many things I can discuss when it comes to steam plant economizers, but that will go deeper into the design measures.
I guess that will be an article for another day.
Thanks for reading, if you have any questions you should leave a comment. See you in another piece of my article.
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