Steam boilers are broadly classified into industrial steam generators and power generation boilers, based on how the steam is generated and used. The classification of steam boilers depends on factors such as the circulation type, firing type, fuel used, construction type and firing system design nature.
A steam boiler refers to an enclosed vessel in which a fluid such as water is heated under high pressure. This heated fluid is used for various purposes including power generation.
Aside from being classified as industrial steam generators and power generation boilers, steam boilers can also be classified as fire-tube and water-tube boilers. Although almost nonexistent, fire tube boilers are further classified into locomotive boilers, domestic-use boilers and industrial boilers, which are mainly used in green projects. Based on the circulation type used in the steam generation, water tube boilers can be classified as natural circulation boilers, zero circulation boilers and forced circulation boilers.
Classifications that depend on the type of firing include stoker-fired boilers, down-short-fired boilers, pulverized-coal-fired boilers, incinerators and fluidized bed boilers, while those that are based on the type of fuel used include coal-fired boilers, oil-fired boilers, gas-fired boilers, biomass-fired boilers and multifuel- fired boilers. Some boilers are arranged in a certain way to achieve a particular purpose. Boilers in this category include top-supported boilers, drum-type boilers, field-erected boilers and package boilers.