大颗粒在循环床密相区运动规律的可视化研究

Visual Research on Big Particle Behavior in Dense-Phase Zone of Circulating Fluidized Bed

在用循环流化床焚烧原生垃圾时,密相区中大尺寸的不可燃物质较多,为了维持正常运行,需要采取有效排渣措施,及时地将这些不可燃物排出,因此需要对大且不可燃物在密相区中的运动规律进行研究。该文设计了一种利用可视化拍摄示踪颗粒运动轨迹,通过图象处理后利用大量统计示踪颗粒位置信息得到颗粒位置概率分布的方法。在建立冷态实验台的基础上,通过实验证明这种方法的可行性。同时发现,当流化风速较高(如2.23m/s时)时,密度较小的示踪颗粒在实验台内会做抛射运动;随着风速的提高,示踪颗粒的抛射运动也会发生变化;而密度较大的示踪颗粒则只会沿着布风板滚到排渣口处停住。

The municipal solid waste （MSW） incinerated in circulating fluidized bed incinerator （CFBI） contains many incombustible particles of long sizes, due to the fact that there is no separate collection of MSW in China. In order to maintain normal operation of the incinerator, effective measures should be applied to discharge the particles in time. Consequently, the characteristic behavior of the big particle in the dense-zone should be studied. A method was researched for further investigation by recording the behavior of the traced particle, processing the images and then obtaining the probability distribution of the particle through large-scale statistics of the particle＇s positions. The method proved to be working experimentally. Lighter or low-density particles were observed to make parabola movements at a high fluid velocity such as 2.23m/s. The parabola behaviors changed as the fluid velocity increased. Oppositely heavier or high-density particles just rolled along the air distributor plate until arriving the exit.