In thermal power plant, the fire tube and water tube boilers are classified based on

Types of boilers in thermal power plant

• In a thermal power plant, fire tube and water tube boilers are classified based on tubular heating surface.
• This classification is based on whether the hot gases pass through the tubes (fire tube) or the water passes through the tubes (water tube) while the combustion gases heat the outside of the tubes.
• Based on the contents of the tubular heating surface, boilers are primarily classified as fire tube boilers and water tube boilers.
   

1.) Fire tube boilers

• Fire tube boilers are those in which the production of combustion passes through the tubes and water tube boilers are those in which the products of combustion surround the water tubes from outside.
• These boilers operate at moderate pressure (16-20bar) and are more suitable to generate 3-8 tons of steam per hour which is used in process heating.
• Cornish boiler is an example of a fire tube boiler and also includes Cochran, Lancashire, Locomotive, and Scotch marine boilers.
   

2.) Water tube boilers

• Water tube boilers are those in which the products of combustion (Hot flue gas) surround the water tubes from outside. Cold water enters the tubes and leaves hot.
• These boilers operate at very high pressures and are used for power generation.
• Ex: Babcock-Wilcox boiler, Stirling boiler.