Characteristics of U-type return valve of circulating fluidized bed

doi:10.11949/j.issn.0438-1157.20190219

Abstract

Abstract:

The investigation of U-type nonmechanical recycling valve is carried out on a cold-circulating fluidized bed (CFB) test facility. The size of the cross section of the valve is used to study the influence of the structural characteristics of the cross section on the return characteristics of the U-type valve. The influence of horizontal opening of U-valve on solids circulating rate are also studied. When the fluidizing gas velocity is constant, the solid circulating rate increases linearly first and then reaches constant. At a given loosing gas rate, the maximal circulating rate of system depends mainly on the fluidizing gas velocity. The optimized opening ratio of the horizontal section is about 25% cross section area of the standpipe.

Key words: U-type valve, opening ratio, circulating fluidized bed, circulating rate, two-phase flow

摘要：

实验对循环流化床物料回送系统的关键部件——U型回料阀的工作特性进行了研究，具体研究了系统中循环流率与主床流化风速和松动风量的关系，以及通过改变U型阀横段开口尺寸，研究横段结构特征对U型阀返料特性的影响。当主床流化风速不变时，随着松动风量的增加，循环流率先线性增大，然后基本保持恒定；当松动风量一定时，系统的最大循环流率与主床流化风速基本为线性关系；实验中得出最佳孔口面积约为料腿截面面积的25%。

关键词: U型阀, 开口率, 循环流化床, 循环流率, 两相流

CLC Number:

TQ 028.8

Sihai ZHANG, Lujian CHEN, Man ZHANG, Xin TAO, Shouyu ZHANG, Hairui YANG. Characteristics of U-type return valve of circulating fluidized bed[J]. CIESC Journal, 2019, 70(8): 2954-2960.

张思海, 陈陆剑, 张缦, 陶欣, 张守玉, 杨海瑞. 循环流化床U型回料阀的特性[J]. 化工学报, 2019, 70(8): 2954-2960.

Figures/Tables 10

Fig.1 Structure of U-type valve (unit: mm)

Fig.2 Schematic diagram of test system

Table 1 Basic parameters of experimental material

物料参数	数值
真密度/(kg/m³)	2045
堆积密度/(kg/m³)	1280
最小流化速度/(m/s)	0.03
临界流化空隙率	0.4083
平均粒径/μm	200

Fig.3 Relation between solid velocity near wall and solid circulating rate

Fig.4 Effect of loosing gas rate on circulating rate

Fig.5 Effect of loosing gas rate and fluidizing gas velocity on circulating rate

Fig.6 Effect of fluidizing gas velocity on maximal circulating rate

Fig.7 Effect of orifice particle velocity on orifice coefficient

Fig.8 Effect of orifice area on orifice coefficient

Fig.9 Effect of orifice area on circulating rate

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