What are the advantages of circulating fluidized bed boilers in boilers compared to older boilers?

Circulating fluidized bed boiler is a specific type of boilers, and compared with the other boilers, it has certain advantages, which are: it has great improvement in combustion technology, which can improve the boiler combustion quality and combustion effect, and in turn, to improve the boiler effect. This is achieved because two return feeders are used in this type of boiler to allow the fuel to form a circulation loop between the furnace and the return feeder.

The advantages of circulating fluidized bed (CFB) boilers compared to older boilers are as follows:
High Combustion Efficiency
Enhanced Heat Transfer: CFB boilers utilize a fluidized bed combustion process, where the fuel is suspended in a high-velocity air stream, creating a large contact area between the fuel and air. This results in more efficient heat transfer and higher combustion efficiency. In contrast, older boilers, such as grate-fired boilers, often have insufficient mixing of fuel and air, leading to lower combustion efficiency.
Long Residence Time of Fuel: In CFB boilers, most unburned fuel can be recirculated through the cyclone separator for multiple combustions, ensuring a longer residence time and more complete combustion. Older boilers may have issues with unburned fuel being discharged, resulting in energy waste.
Fuel Flexibility
Wide Range of Fuels: CFB boilers can burn a variety of fuels, including high-quality coal, low-quality coal, biomass, waste materials, and more. This provides greater flexibility in fuel selection and allows for the use of cheaper or locally available fuels, reducing fuel costs and mitigating supply chain issues. Older boilers, such as pulverized coal boilers, have stricter requirements for fuel type and particle size, resulting in higher fuel preparation costs.
Tolerance to Fuel Fluctuations: CFB boilers are tolerant of fuel fluctuations and other disturbances, making them more adaptable to changes in fuel quality and supply. This is particularly important in situations where fuel sources are unstable or vary significantly.
Low Emissions
In-furnace Desulfurization: CFB boilers can add limestone for in-furnace desulfurization, significantly reducing sulfur dioxide emissions. This process is more efficient and cost-effective compared to post-combustion desulfurization methods used in older boilers.
Low Nitrogen Oxide Emissions: The lower combustion temperature in CFB boilers (around 860°C) helps reduce the formation of nitrogen oxides. Additionally, the fluidized bed combustion process allows for better control of air staging, further lowering nitrogen oxide emissions. In contrast, older boilers, such as pulverized coal boilers, typically have higher nitrogen oxide emissions.
Good Load Regulation Performance
Wide Load Adjustment Range: CFB boilers have a load adjustment range of up to 4:1 and a load adjustment speed of 5-8% BMCR/min. This allows them to quickly respond to changes in power demand and maintain stable operation under varying load conditions. Older boilers may have more limited load regulation capabilities, affecting their operational flexibility and efficiency.
Easy Hot Standby and Start-up: CFB boilers can easily achieve pressure fire hot standby, with minimal oil consumption during warm start and no oil required for hot start. This reduces the fuel consumption and operational costs associated with start-up and shutdown.
Simplified Fuel Preparation System
No Coal Grinding System: The fuel particle size for CFB boilers is typically 0-13mm or 0-8mm, eliminating the need for a coal grinding system. This greatly simplifies the fuel preparation process compared to pulverized coal boilers, reducing equipment costs and maintenance requirements.
Enhanced Environmental Performance
Lower Emissions of Pollutants: CFB boilers achieve lower emissions of sulfur dioxide and nitrogen oxides through in-furnace desulfurization and controlled combustion temperatures. This helps reduce the environmental impact of power generation and meets increasingly stringent environmental regulations.
Reduced Ash and Slag Generation: The fluidized bed combustion process in CFB boilers results in more complete combustion and less ash and slag generation. This reduces the amount of waste produced and the associated disposal costs.