循环流化床一、二次风管网特性及风机选型研究

通过分析循环流化床（circulating fluidized bed,CFB）锅炉一、二次风的管网特性,并结合电站CFB锅炉的运行参数,对大型CFB锅炉一、二次风机的选型进行了研究。结果表明：CFB锅炉一次风所需最大风量与最高压头不在同一工作点上,具有与煤粉锅炉一次风完全不同的管网特性。CFB锅炉二次风的管网特性与煤粉锅炉二次风的管网特性类似,不同之处在于其管网阻力中增加了由炉内颗粒浓度产生的压降;CFB锅炉一次风机选型时应使管网特性曲线完全落在风机的性能曲线内,并采用能耗较低的变速调节或入口导叶调节。CFB锅炉二次风机选型原则与普通离心风机选型原则类似,但应估计出由颗粒浓度所产生压降的大小,对300 MW CFB机组来说,其值在5.5~7.5 kPa范围内。

Study on Pipeline Characteristics and Selection of Primary and Secondary Air Fans for CFB Boilers

Through analyzing the pipeline characteristics of the primary air and secondary air on circulating fluidized bed （CFB） along with several operating data from commercial CFB boilers, the selection principles of primary air fan and secondary air fan are studied. The results indicate that the maximum air flow and maximum pressure head of the primary air of a CFB boiler are not at the same operating point, forming a pipeline characteristic completely different from that of a pulverized coal boiler. The pipeline characteristic of the secondary air of a CFB boiler is similar to that of a pulverized coal boiler, but with the pressure drop produced by the particle concentration in the furnace added to the system resistance. When a primary air fan is selected for CFB boilers, the pipeline characteristic curve should be entirely included by the fan performance curve, and inlet guide vane adjustment or variable speed adjustment of lower energy consumption should be adopted. The selection principle of the secondary air fan for the CFB boiler is similar to that of the centrifugal fan with the pressure drop caused by bed materials beingestimated. For 300-MW CFB units, the pressure drop is usually between 5.5 kPa and 7.5 kPa.