The fluidized bed boiler is a boiler that uses a fluidized bed combustion method. Fluidized bed boilers can be divided into bubbling fluidized bed boilers and circulating fluidized bed boilers according to their hydrodynamic characteristics. Fluidized bed boilers can be divided into atmospheric fluidized bed boilers and pressurized fluidized bed boilers according to the flue gas pressure in the furnace. Fluidized bed combustion (FBC) is a combustion technology that can be fired on coal and biomass, among other fuels. Fluidized beds suspend solid fuels on upward-blowing jets of air during the combustion process. The result is a turbulent mixing of gas and solids. The tumbling action provides more effective chemical reactions and heat transfer.
The fluidized bed boiler mainly produced by ZBG is circulating fluidized bed boiler, which can be divided into coal-fired boilers, biomass boilers and power station boilers. This CFBC technology utilizes the fluidized bed principle in which crushed fuel and limestone are injected into the furnace or combustor. The particles are suspended in a stream of upwardly flowing air (60-70% of the total air), which enters the bottom of the furnace through air distribution nozzles.
Major performance features of the circulating bed boiler system are as follows:
1. It has high combustion efficiency.
2. It has a high processing capacity because of the high gas velocity through the system.
3. The temperature of about 870 °C is reasonably constant throughout the process because of the high turbulence and circulation of solids. The low combustion temperature also results in minimal NOx formation.
4. Sulphur present in the fuel is retained in the circulating solids in the form of calcium sulphate and removed in solid form