高传质快速响应的循环流化床炉内脱硫研究

Study on Circulating Fluidized Bed Boiler Desulfurization with High Mass Transfer and Fast Response

为应对当前火电机组变负荷运行引起的炉内SO2生成浓度变化幅度大的现状,实现炉内脱硫高效快速响应,以某350 MW循环流化床锅炉为研究对象,将炉内喷钙位置由回料腿改造为二次风管,通过试验对比了不同喷钙位置对炉内脱硫效率及脱硫响应时间的影响。结果表明,在190 MW、250 MW负荷下,相比于回料腿喷钙,二次风管喷钙可使锅炉出口SO2浓度分别降低103 mg/Nm^(3)、226 mg/Nm^(3),脱硫效率分别从89.99%、88.53%提高到91.52%、91.78%;回料腿喷钙脱硫响应时间为3 min,而二次风管脱硫响应时间仅为1 min。相比于回料腿喷钙,采用二次风管喷钙的炉内脱硫方式既可提高炉内脱硫效率,又可大大缩短炉内脱硫响应时间。实际运行中,可优先选择二次风管给料方式进行炉内脱硫。

In order to deal with the challenge that the concentration of SO2 emitted in the furnace varies greatly due to the variable load operation of thermal power units,and to realize the efficient and rapid response of in-fur-nace desulfurization,with a 350 MW circulating fluidized bed boiler with retrofit of limestone injection from the return leg to the secondary duct as the research object,and the effects of different calcium spraying positions on the efficiency and response time of in-furnace desulfurization are compared through the test.The results show that under 190 MW and 250 MW loads,compared with calcium spraying in the return leg,calcium spraying in the secondary duct can reduce the boiler outlet SO2 concentration by 103 mg/Nm^(3) and 226 mg/Nm^(3),respective-ly,and increase the desulfurization efficiency from 89.99%and 88.53%to 91.52%and 91.78%,respective-ly;the response time of calcium desulfurization in the return leg is 3 min,while the response time of desulfuriza-tion in the secondary duct is only 1 min.Therefore,compared with calcium injection in the return leg,the fur-nace desulfurization method with calcium injection in the secondary duct can not only improve the efficiency of desulfurization in the furnace,but also greatly reduce the response time.In practice,the secondary duct feeding method can be preferred for furnace desulfurization.