大型循环流化床锅炉采用多个旋风分离器与炉膛出口并联布置实现气固分离。入121烟道的布置方式(入口角度和位置)对旋风分离器的性能有显著影响。针对600MW超临界循环流化床锅炉,对6个旋风分离器并联布置方式进行了实验研究和数值模拟。实验结果表明,6个旋风分离器之间存在着分配不均现象;在相同条件下,不同位置的旋风分离器压降和返料流率均有一些差异,在炉膛同一侧,位于中间的旋风分离器的压降和返料流率均低于位于两端的旋风分离器的压降和返料流率。数值模拟结果显示,不同位置的旋风分离器之间气相流率分配基本均匀,在炉膛同一侧,进入两端的旋风分离器的颗粒流率要高于进入中间的旋风分离器的颗粒流率;位于两端的旋风分离器,颗粒贴着入口烟道外壁进入,处于较好的分离状态,而位于中间位置的旋风分离器,有部分颗粒冲击入口烟道内壁,不利于分离。
It is common to adopt several cyclones in parallel to the furnace to separate dust from gas in a large capacity circulating fluidized bed (CFB). Different arrangements of cyclones affect the separator performance greatly. For a 600 MW supercritical CFB boiler, the experimental and numerical studies on the arrangement of 6 cyclones were conducted. The experimental results show that the pressure drops and corresponding solid flow rates of the 6 cyclones are different. The pressure drop as well as the corresponding solid flow rate of the cyclone in the center is smaller than that of the other two in the same side of the furnace. The numerical results show that the distribution of the gas phase is uniform, while the solid flow distribution is significantly non-uniform. Corresponding with the experimental results, the solid flux of the inlet duct in the center is smaller than that of the other two in the same side of the furnace. For the cyclones in the center, a part of particles from the furnace rush to the inner wall of the inlet duct, which is not good for separation, but the other cyclones in the corners of the furnace are in a better state of separation.