Effects of inlet distributor on particle flow characteristics in 18 m circulating fluidized bed riser

doi:10.11949/j.issn.0438-1157.20180016

Abstract

Abstract:

Three kinds of riser inlet distributors were designed to investigate their effects on particle flow characteristics in a CFB riser with 18 m in height and 80 mm in diameter. The results show that inlet distributors have significant impact on particle hydrodynamics at the bottom region of the riser and different inlet distributors have different effects as indicated by characteristic length of the developing section. At the same operating condition, multiple tube inlet had uniform radial distribution of solid holdup and particle movement reached fully-developed state at about 9 m in axial direction, whereas perforated plate inlet had large concentration difference at bottom and particle movement developed slowly in axial direction requiring about 11 m in length to reach fully-developed state. On the other hand, single tube inlet had radial solid holdup and axial development region somewhere between those of the other two inlets. The single tube inlet had non-uniform radial solid holdup distribution of dilute center and dense side at the bottom of the riser and required 10 m axial length to reach fully-development state.

Key words: circulating fluidized bed, riser, two-phase flow, inlet distributor

摘要：

在高18 m、内径80 mm的循环流化床提升管内分别考察了三种入口结构对颗粒流动特性的影响。实验结果表明：入口结构主要影响提升管底部区域的颗粒流动特性，不同入口结构对颗粒流动影响不同。相同操作条件下，当采用多管式入口结构时，径向上提升管底部区域的颗粒浓度分布相对均匀，轴向上颗粒能够迅速达到充分发展状态，充分发展高度在9 m左右；当采用多孔板入口结构时，径向上提升管底部颗粒浓度差别较大，轴向上颗粒发展较慢，需要更高高度才能达到充分发展，充分发展高度约为11 m；当采用单管式入口结构时，径向上颗粒浓度分布和轴向上颗粒充分发展速度均处于前两者之间，底部颗粒浓度径向分布仍为中间稀、边壁浓的不均匀分布，颗粒浓度轴向充分发展高度约为10 m。

关键词: 循环流化床, 提升管, 两相流, 入口结构

CLC Number:

TQ021.1

MAO Xiaoyang, WANG Chengxiu, LAN Xingying, GAO Jinsen. Effects of inlet distributor on particle flow characteristics in 18 m circulating fluidized bed riser[J]. CIESC Journal, 2018, 69(5): 1931-1937.

毛晓阳, 王成秀, 蓝兴英, 高金森. 入口结构对18 m气固循环流化床提升管内颗粒流动特性的影响[J]. 化工学报, 2018, 69(5): 1931-1937.

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