Classification of boilers

Thread Content

1. Classification by purpose: Power station boilers: Used for power generation; they are mostly large-capacity, high-parameter boilers that operate with combustion in the fire chamber, offering high efficiency, with the exit fluid being superheated steam. Industrial boilers: Used for industrial production and heating; most of them are low-pressure, low-temperature boilers with small capacity. They primarily use a firebed for combustion, resulting in low thermal efficiency. Boilers whose output is steam are called steam industrial boilers, while those whose output is hot water are called hot water boilers. Marine boilers, locomotive boilers, steam injection boilers: used in oil fields for steam injection thermal recovery of heavy oil; the output fluid is generally high-pressure wet steam. 2. Classification by structure: Fire-tube boilers: Flue gas flows inside the fire tubes; these are generally boilers of small capacity and low parameters, with low thermal efficiency. However, they have a simple structure, require low standards regarding water quality, and are easy to operate and maintain. Water-tube boilers: Steam and water flow inside the tubes; they can be designed as boilers with small capacity and low parameters, or as boilers with large capacity and high parameters. Power station boilers are generally water-tube boilers, which offer high thermal efficiency, but they also require high standards regarding water quality and operating conditions. 3. Classification by circulation mode: Natural circulation drum boilers, multiple forced circulation drum boilers, low-rate circulation boilers, direct-flow boilers, compound circulation boilers. 4. Classification by the pressure of the fluid at the boiler outlet: Low-pressure boilers: generally with a pressure of less than 1.275 MPa; Medium-pressure boilers: generally with a pressure of 3.825 MPa; High-pressure boilers: generally with a pressure of 9.8 MPa; Ultra-high-pressure boilers: generally with a pressure of 13.73 MPa; Subcritical-pressure boilers: generally with a pressure of 16.67 MPa; Supercritical-pressure boilers: generally with a pressure of 22.13 MPa. 5. Classification by combustion method: Bed combustion boilers: mainly used in industrial boilers, including fixed grate boilers, reciprocating grate boilers, etc. Firebox combustion boilers: Primarily used in power station boilers; boilers that burn liquid fuels, gaseous fuels, and coal powder are all firebox combustion boilers. Boiling furnace: The air flow rate supplied to the grate is high, causing larger coal particles to burn vigorously in the boiling bed on top of the grate, while smaller coal particles rise with the air and burn as well. 6. Classification by fuel or energy source: Solid-fuel boilers: those that use solid fuels such as coal ； Liquid fuel boilers: burn liquid fuels such as heavy oil ； Gas fuel boilers: fueled by gas fuels such as natural gas ； Waste heat boiler: Uses the waste heat from industries such as metallurgy and petrochemicals as a heat source ； Nuclear power boilers: Steam generators that use the heat released by nuclear reactors as a heat source ； Waste heat boiler: A boiler that uses waste materials such as garbage, bark, and waste liquids as fuel ； Other energy boilers: Steam generators or water heaters that utilize energy sources such as geothermal heat and solar energy. 7. Classified by slag discharge method: Solid slag discharge boilers, Liquid slag discharge boilers. 8. Classified by flue gas pressure in the furnace: Negative pressure boilers: The furnace pressure is kept at a negative level; they are equipped with forced draft and exhaust fans, and represent the main type of coal-fired boilers ； Micro-positive pressure boiler: gauge pressure in the furnace is 2–5 KPa; no exhaust fan is required, enabling easy low-oxygen combustion ； 9. Classification by drum arrangement: Boilers generally have one or two drums, which can be arranged vertically or horizontally. Modern drum-type power station boilers all use a single-drum design, while industrial boilers employ either a single-drum or double-drum design. 10. Classification by boiler type: There are many types of boilers, including inverted U-shaped, tower-shaped, box-shaped, T-shaped, U-shaped, N-shaped, L-shaped, D-shaped, A-shaped, etc. Type D and Type A are used in industrial boilers, while other types are generally used in power station boilers. 11. Classification by boiler room type: Boilers can be installed in open areas, semi-open areas, indoors, underground, or in cavities. Industrial boilers are generally installed indoors, while power station boilers are mainly installed indoors, in semi-open areas, or in open areas. 12. Classified by the boiler’s type at the time of manufacture, they can be divided into quick-install boilers, assembled boilers, and bulk boilers ； Small boilers can adopt a quick-installation design, while power station boilers are generally assembled or supplied in bulk.