Babcock And Wilcox Boiler: Components And Working Principle

In this article, I will share the components and working principles of the Babcock and Wilcox boiler.


Don’t be surprised by this type of boiler, it’s just like any other type of water tube boiler.


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The water in this type of boiler is passed through several tubes while the combustion gasses from the furnace are passed over them.


That is the typical working condition of a water tube boiler.


The only difference when it comes to Babcock and Wilcox boilers is their construction.


It’s very unique from the normal boilers you are used to seeing in the industries.


For you to know what I mean, let me share with you the components of this type of boiler.


Main components of Babcock and Wilcox boiler

The Babcock and Wilcox boiler to be functional, these are the main components it should contain;

  1. A drum
  2. Superheater
  3. The tubes
  4. The headers
  5. The grate
  6. The baffles


A drum

This is where the boiler water is stored and gradually supplied to the tube for steam generation.



It’s used to superheat the steam to increase its thermal energy thus increasing the efficiency of the boiler.


There are several benefits when it comes to superheating the steam, it not only increases the thermal energy of the steam but also dries it up.


You might like this: Advantages Of Using Superheated Steam


The tubes

They are used to carry the water from the boiler drum and pass it through the entire series of interconnected tubes (header)


The headers

They are interconnected tubes that form the real heating element.


The water in the tube gets heated by the combustion gasses from the furnace.


Interconnecting the tubes increases the rate of heat transfer from the combustion gasses since their surface area are increased.


The grate

It’s where the fuel is burnt and combustion gasses are passed over the tubes to allow heat transfer.


The baffles

They are used to provide a zigzag path for the combustion gasses thus increasing the heat transfer to the water tubes.


These are just a few components that are really important to know if you want to capture the working principle of the Babcok and Wilcox boiler.


Of course, the other components and accessories are present to increase the efficiency of the boiler.


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Things like the valves, stack, manhole, mud box and so many other mountings and accessories are available in this type of boiler.


It’s time for me to share the working principle of this type of boiler.


Working principle of Babcok and Wilcox boiler.

The cold water from the feed water tank enters the boiler drum and circulated inside the entire tube system.


This is to ensure that the water from the boiler drum reaches every part of the tube to prevent uneven heat distribution on the tubes, increase the steam generation and increase the pressure of the steam generated.


The fuel is burnt on the grate and its combustion gasses are transferred to the header (heating element) thus passing them over the water tubes to enable maximum heat transfer.


With the aid of the baffles, the combustion gasses go through a zigzag path over the water tube to increase the time of contact thus increasing heat transfer per volume of combustion gasses.


This also ensures that the combustion gasses from the furnace are used to the maximum leaving a small room for heat to escape to the atmosphere.


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When the water in the tubes is heated sufficiently by the combustion gasses passing over them, the hot water and steam rise up through the uptake header since the header is tilted.


The cold water from the boiler drum is on the downtake header of the heating element.


It’s in the boiler shell where the separation of steam and hot water happens leaving the steam in steam space while the water flows down through the downtake header to be heated sufficiently.


The steam needs to be superheated before it’s supplied to the point of application because it was initially in contact with the water.


The superheated steam is taken out via the steam stop valve.


After the combustion gasses have been used to heat the water in the tubes, they are directed out of the boiler using the stack.


Don’t forget that the flue gasses have to be passed through the air preheater, boiler economizer and even the superheater to reduce heat losses and maximize the efficiency of the boiler.




That will be it guys, the short summary of the working principle of the Babcok and Wilcox boiler.


The functionality of the Babcock and Wilcox boiler is just similar to any water tube boiler.


But you should expect a variation in size and design because of how this boiler is built.


To increase the efficiency of this boiler even further, one should consider finding a way to reduce as much heat loss as possible and use the right water tubes that will increase heat transfer.


Of course other practices, like using the preheated air in the furnace, heating the boiler feed water and using the economizer are going to increase the efficiency of the boiler too.


You might like this: 4 Reasons Why Boiler Feed Water Needs To Be Heated


I hope you have found value in this article, if you have any questions or additional points you would me to add to this article, feel free to reach out to me.


Thanks for reading. See you in the next article.


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