Difference between Fire tube boiler and Water tube boiler. By Yuvi - Study Point

Hey everyone, today we are going to learn the difference between the fire tube and water tube boiler in an easy way.
So, without wasting any time lets get started.

• Fire-tube boiler

1. In fire tube boilers water surrounds the hot flue gases which were passing through the tube which means water is flowing from outside of the tube or we can say water flows from the shell.  
2. The fire-tube boilers are generally low or medium pressure boilers and they generally operate at low pressure up to 20 bar. 
3. In fire tube boilers there are disadvantages like load fluctuations cannot be handled.
4. The efficiency of fire tube boilers is less as compared to water tube boilers. Its efficiency is up to 75 % and it can be increased by using some other accessories. 
5. It has a very low rate of steam generation and quality of steam is also very low therefore it is not suitable for power generation. These boilers are almost internally fired and at the one end of the fire tube boiler, a furnace is placed.
6. For a given output it requires more area.
7. In fire tube boilers water doesn't circulate in a definite direction.
8. Fire tube boilers are bulky, difficult to transport, difficult to repair & cleaning and also difficult to construct.
9. Fire tube boilers are used in process industries which means these boilers are suitable for production work like textile industries, sugar mill, etc.
10. In fire tube boilers the drum size is large and damaged caused by bursting is also large but due to low pressure, the risk of explosion in fire tube boilers is low.
11. Fire tube boilers are situated inside the shell so due to this large shell diameter is required. 
12. Fire-tube boilers have a low maintenance cost, its design is very easy or simple and also very easy to erect.
13. Fire-tube boilers require less skill to operate because less skilled operators are sufficient for efficient operation.
14. Ex ~ simple vertical boiler, locomotive boiler, etc.

• Water-tube boiler

1. Water-tube boilers are completely equal and opposite of fire tube boilers as in water tube boilers hot flue gases surrounds the water which was flowing or passes through tubes or we can say flue gases pass over the tubes or flows from the shell.
2. Water-tube boilers pressure is up to 70 - 100 bar. So these boilers are generally high-pressure boilers and in supercritical boilers, the working pressure is high enough up to 250 bar.
3. In water-tube boilers, load fluctuations can be easily handled. 
4. Water-tube boilers are more efficient as compare to fire tube boilers because its efficiency is up to 90 %.
5. These boilers are generally externally fired, it has a high rate of steam production, rate of steam generation and also the quality of steam are much better and suitable for power generation.
6. For a given output, water-tube boilers require less floor area.
7. In water-tube boilers, the direction fo water circulation is well defined. 
8. Transportation is not a problem for water-tube boilers because these are light in weight, it is simple in construction, easily repairable, easy to clean due to externally fired.
9. Risk of an explosion is higher in water-tube boilers as compare to fire-tube boilers but if any water tube is damaged then it can be easily replaced or repaired.
10. Its maintenance cost is high, it is difficult to erect and also it has a complex design as compare to fire-tube boilers.
11. Water-tube boilers are used or we can say it is suitable for large power plants.
12. Water-tube boilers require small shell diameter.
13.  In water-tube boilers, its operation is only done by skilled operators.'
14. Ex ~ Sterling boilers, etc.

https://youtu.be/1LgG16L3cQ4

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