Comparison between Fire tube and Water tube boilers

Boiler:

A boiler is a device used to generate steam at a desired pressure and temperature by transferring heat energy produced by burning fuel to water to change it to steam. 

It is a combination of apparatus used for producing, furnishing or recovering heat together with the apparatus for transferring the heat so made available to the fluid being heated and vaporized. 

Comparison between Fire tube and Water tube boilers:

 

Following are the few points of comparison between Fire tube and Water tube boiler:

No.	Fire tube boiler	Water tube boiler
1	In Fire-tube boilers hot flue gases pass through tubes and water is surrounds them.	In Water-tube boilers water passes through tubes and hot flue gasses is surround them.
2	The working pressure is low up to 20 bar.	The working pressure is high enough, up to 250 bar.
3	The steam generation rate and quality of steam are very low, therefore, not suitable for power generation.	The steam generation rate and quality of steam are better and suitable for power generation.
4	It is generally internally fired.	It is externally fired.
5	It occupies more floor area for a given output.	It occupies less floor area for a given output.
6	These are bulky and transportation is difficult.	These are light in weight, hence transportation is simple.
7	Its overall efficiency is up to 75%.	Its overall efficiency with an economizer is up to 90%.
8	Water treatment is not necessary.	Water treatment is necessary.
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	The bursting chance of fire tube boiler is less.	The bursting chance of water tube boiler is more.
11	Simple in design, easy to erect and low maintenance cost.	Complex, design, difficult to erect and high maintenance cost.
12	Skilled operators are not necessary for efficient operation.	Skilled operators are required for efficient operation.
13	Its operating cost is less.	Its operating cost is more
14	Fire tube boiler is used in process industry.	Water tube boiler is used in large power plants.