Model prediction and experimental study of pressure drop in double circulating fluidized bed risers of gas-solid two-phase flow

doi:10.11949/j.issn.0438-1157.20170738

Abstract

Abstract:

In order to study effect of particulate circulating flow rate on pressure drop in riser, a cold experiment system of double circulating fluidized bed was established with differential pressure transmitters to probe axial pressure drop in riser. Based on various calculation methods of particulate velocity and different pressure drop mechanisms in different areas, pressure drop models were built for acceleration area, fully developed area, and whole riser. Pressure drop in the acceleration area by slip coefficient calculation was consistent with experimental value, while pressure drop in the fully developed area was relatively accurate upon assuming particulate slip velocity equal to terminal velocity. Therefore, pressure drop calculation in riser by comprehensive pressure drop models in the acceleration and fully developed areas could be good reference for pressure drop to be used in prediction of axial particulate concentration distribution in riser during production and provide guidance for on-line pressure drop monitoring in riser.

Key words: circulating fluidized bed, two-phase flow, riser, pressure drop, particulate velocity, acceleration area, fully developed area

摘要：

为研究提升管颗粒循环流率对提升管压降的影响，搭建双循环流化床冷态实验系统，采用差压变送器进行提升管轴向区域压降的实验研究。基于提升管不同的颗粒速度计算方法，充分考虑加速区和充分发展区的不同压降机理，建立加速区、充分发展区和整个提升管压降模型，与实验结果比较发现：加速区颗粒速度采用滑移系数方法所得压降与实验值较吻合，在充分发展区进行压降计算时颗粒速度采用滑移速度等于终端速度计算所得结果较精确；在提升管压降计算时可综合考虑加速区和充分发展区适用的压降模型进行计算，可为实际生产运行中采用压差法进行提升管轴向颗粒浓度的分布提供一定参考，为提升管压降的在线监测提供指导。

关键词: 循环流化床, 两相流, 提升管, 压降, 颗粒速度, 加速区, 充分发展区

CLC Number:

TK229

YANG Xin, CHEN Hongwei, LIANG Zhanwei, XU Wenliang, SUN Chao. Model prediction and experimental study of pressure drop in double circulating fluidized bed risers of gas-solid two-phase flow[J]. CIESC Journal, 2017, 68(12): 4585-4591.

杨新, 陈鸿伟, 梁占伟, 许文良, 孙超. 基于气固两相流的双循环流化床提升管压降模型的预测和实验研究[J]. 化工学报, 2017, 68(12): 4585-4591.

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