Low-speed CFB Boiler features a clean combustion technology with high efficiency, less energy and low pollution emission.
Low-speed CFB Boiler Characteristics
1) Since the boiler has separator and refeeder, the furnace contains a large amount of heat storage materials. These circulated materials will have high heat transfer coefficient, which is beneficial to preheating, burning and burnout of fuel.
2) The operating temperature of circulating fluidized bed boiler is usually within 800-900℃. When adding limestone, the desulfurization efficiency in the furnace can reach over 95%. The initial SOx emission concentration can reach 80mg/Nm3. When adopting staged air supply technology, the generation and emission of NOx can be greatly reduced. NOx emission can reach 50mg/Nm3 even without SNCR.
3) CFB boiler also has high combustion efficiency, comprehensive utilization of ash and slag, wide heat load adjustment.
Change the original air supply and refeeding mode, move down the return air and divide into several independent wind boxes. It adopts low nitrogen combustion technology with low temperature graded air supply in furnace. Adopt flue gas recirculation technology to minimize the supply of primary air. The secondary air can be reasonably sent into lower furnace in two layers.
An independent limestone interface is creatively set on the secondary air duct. The particle size of limestone is generally at 0-1.2mm, and the combustion temperature of fluidized bed is at 850~890℃. Limestone is injected into furnace by pneumatic conveying system with silo pump. The fuel and desulfurizer are repeatedly cycled to carry out low-temperature combustion and desulfurization reaction. Ca/S ratio is 1.2-1.8, the desulfurization efficiency can reach 95%, and the emission of SOX can reach 80mg/m3.
Rated evaporation capacity of the low-speed CFB boiler is 50t/h, rated pressure is 1.25MPa, and feed water temperature is 104℃. The furnace temperature is 865℃, the exhaust gas temperature is 135℃, and the excess air coefficient is 1.25. SOx emission concentration is 75mg/Nm 3, and NOx emission concentration is 48mg/Nm3, The power consumption of boiler system is as low as 10.1kWh per ton of steam. Boiler body includes combustion device, furnace, separator, refeeder, convection tube bundle, economizer, air preheater, etc.
Post time: Oct-30-2021