Boiler structure

The overall structure includes the boiler body and auxiliary equipment.

The main components in the boiler, such as the furnace, drum, burner, water-cooled wall superheater, economizer, air preheater, frame and furnace wall, constitute the core part of the steam production, which is called the boiler body. The two most important parts of the boiler body are the furnace and the drum.

Furnace, also called combustion chamber, is the space for fuel to burn. The furnace that puts solid fuel on the grate and burns on the fire bed is called a layer burner, also called a fire bed furnace; the furnace that burns liquid, gas or powdered solid fuel into the fire chamber is called a chamber Combustion furnace, also known as the fire chamber furnace; the air holds the coal particles to make them burn in a boiling state, and the furnace suitable for burning inferior fuel is called a boiling furnace, also called a fluidized bed furnace; the air particles are used to rotate the coal particles at high speed The intensely burning cylindrical hearth is called a cyclone furnace. The cross section of the furnace is generally square or rectangular. Fuel burns in the hearth to form flames and high-temperature flue gas, so the furnace walls around the hearth are made of high-temperature resistant materials and thermal insulation materials. Water-cooled wall pipes are often laid on the inner surface of the furnace wall, which not only protects the furnace wall from burning, but also absorbs a large amount of radiant heat from flames and high-temperature smoke. Furnace design needs to fully consider the characteristics of the fuel used. Every boiler should use as much fuel as originally designed. When fuels with widely different characteristics are used, the economy and reliability of boiler operation may be reduced.

The drum is a cylindrical container that accepts feed water from the economizer, connects the circulation circuit, and sends saturated steam to the superheater in natural circulation and multiple forced circulation boilers. The drum is made of high-quality thick steel plate, which is one of the heaviest parts in the boiler. The main function of the drum is to store water and separate steam and water. During operation, the brine and mud in the boiler water are eliminated, and the boiler water containing high concentrations of salt and impurities is prevented from entering the superheater and the steam turbine with the steam. The internal device of the drum includes a steam-water separation and steam cleaning device, a water supply distribution pipe, a sewage and a dosing device and the like. The role of the steam-water separation device is to leave the saturated steam and water from the water-cooled wall and minimize the small water droplets carried in the steam. Medium and low pressure boilers commonly use baffles and gap baffles as rough separation elements. In addition to widely used cyclone separators for rough separation, boilers above medium pressure also use shutters, wire meshes or steam equalizing plates for further separation. . The drum is also equipped with monitoring and protection facilities such as water level meters and safety valves.