Circulating fluidized bed boiler is a type of steam generator with the addition of a component that separates the incomplete fuel in the fluidized bed combustion process. The function of this add-on is to help completely burn the particles and fuel that have not been completely burned. Therefore, this type of boiler is considered an improvement over foam fluidized bed boiler. For this type of fluidized bed boiler, the fuel will quickly mix with the fluidized bed material, resulting in high fuel combustion efficiency.
1. Working principle of circulating fluidized bed boiler
In the combustion chamber of the circulating fluidized bed boiler, the new fuel will receive heat from the boiling material layer consisting of the combustible fuel and the boiling buffer particle mixture. The boiling buffer particle mixture is responsible for raising the temperature of the fuel to the combustion temperature. When ignited, the fuel generates heat and the combustion products are ash, slag, and smoke.
Structure of circulating fluidized bed boiler
The heat generated during combustion will be transferred to the tube wall of the combustion chamber and the tube in the furnace body. The water in the tube wall of the combustion chamber and the tube wall of the furnace body will receive heat from the tube wall, evaporate, increase the pressure, and move to the top of the steam drum. At the steam drum, the steam separates from the liquid phase and enters the steam duct up to the point of use.
Part of the furnace smoke, fly ash and part of unburnt fuel fly out of the combustion chamber and then to the fuel circulation separator. In a fuel cycle separator, unburnt fuel elements are separated from the smoke stream and returned to the combustion chamber for complete combustion. Smoke leaving the fuel recirculation unit will be led through the water bath heater, the air dryer to take advantage of the remaining heat. The exhaust gas then goes to the dust filter, where the dust and pollutants in the exhaust gas are separated. Finally, the flue gas in the furnace is blown into the chimney through the exhaust fan and discharged into the environment.
2. Advantages of circulating fluidized bed boiler
High labor productivity: This is the outstanding advantage of this type of boiler. Because of the principle of burning fuel by volume, the combustion chamber of a circulating fluidized bed boiler will be smaller than that of other conventional boilers. Therefore, the use of circulating fluidized bed boilers can reduce heat loss to the outside environment, thereby helping to improve working efficiency and protect the environment.
Circulating fluidized bed boilers are increasingly used in factories because of their superior characteristics
Better heat exchange: Because the fuel is suspended in the combustion chamber, the combustion chamber space of the circulating fluidized bed boiler will be larger, helping the heat exchange process to be better.
Environmentally friendly: The operation of the boiler helps to minimize emissions to the outside environment.
Thuan Hai Joint Stock Company
Address: Thuan Hai Building, Lot Vb.20a2, Street 24, Tan Thuan Export Processing Zone, Tan Thuan Dong Ward, District 7, City. Ho Chi Minh, Vietnam
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