粒状多晶硅制备的内循环流化床反应器研究

摘要

Fluidized bed process preparing polysilicon granules is a method of great advantages for its lower energy consumption and higher efficiency. Internal Circulation Fluidized Bed (ICFB) can effectively prevent the deposition of silicon on the heating wall. Fluidization behaviors of wide size distribution particles in actual production process were investigated in this paper. The results showed that fluidization quality of wide range particles was much better than narrow ones. Segregating fluidization of wide size distribution particles was restrained in an ICFB for the circulation of particles. The solids holdupes, solids circulation rate Gs and bypassing fraction γRD and γDB in an ICFB were experimentally studied. When UD/Umf and UR/Umf were between 2.5~3.2 and 2.2~2.7, respectively, γRD was smaller than 4%. A results from an estimation showed the ICFB in this article can meet the need of heat supply and reduce the deposition on the heating wall.%制备粒状多晶硅的流化床工艺在能耗和效率上具有明显优势，使用内循环流化床（ICFB）可以显著减少加热壁面的硅沉积。为此对内循环流化床（直径300 mm，高2000 mm）冷模装置进行了实验研究，考察了宽筛分颗粒的流化行为。结果表明内循环流化床中颗粒整体循环流动有效抑制了分级流化。针对供热和气体旁流两个核心问题，考察了固含率、颗粒循环速度以及气体旁流的变化规律。当环隙区流化数UD/Umf和导流筒内流化数UR/Umf分别在2.5~3.2和2.2~2.7时，由中心筒到环隙的气体旁流量γRD小于4%。基于衡算和热态实验数据进行估算，表明内循环流化床能够满足供热需求并能有效抑制加热壁面硅沉积。