S.No | Fire tube boiler | Water tube boiler |
1 | In Fire-tube boilers hot flue gases pass through tubes and water surrounds them. | In Water-tube boilers water passes through tubes and hot flue gasses surround them. |
2 | These are operated at low pressures up to 20 bar. | The working pressure is high enough, up to 250 bar in super critical boilers. |
3 | The rate of steam generation and quality of steam are very low, therefore, not suitable for power generation. | The rate of steam generation and quality of steam are better and suitable for power generation. |
4 | Load fluctuations cannot be handled. | Load fluctuations can be easily handled. |
5 | It requires more floor area for a given output. | It requires less floor area for a given output |
6 | These are bulky and difficult to transport. | These are light in weight, hence transportation is not a problem. |
7 | Overall efficiency is up to 75%. | Overall efficiency with an economizer is up to 90%. |
8 | Water doesn’t circulate in a definite direction. | Direction of water circulated is well defined. |
9 | The drum size is large and damage caused by bursting is large. | If any water tube is damaged, it can be easily replaced or repaired. |
10 | It requires more floor area for a given output. | It requires less floor area for a given output |
11 | Simple in design, easy to erect and low maintenance cost. | Complex, design, difficult to erect and high maintenance cost. |
12 | Even less skill operators are sufficient for efficient operation. | Skilled operators are required for operation. |
13 | The treatment of feed water is not very essential, as overheating due to scale formation cannot burst thick shell. | Treatment of feed water is very essential as small scale deposits inside the tubes can cause overheating and bursting. |
14 | Used in process industry. | Used in large power plants. |
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