Simulation investigation of the baffle overlapping rate on three-phase separation efficiency in a typical UASB reactor

3rd International Conference on Energy Engineering and Environmental Protection

能源学;生态环境科学

Hao, Feilin^1 ; Shen, Mingwei^2

College of Biology and Environmental Engineering, Zhejiang Shuren University, Hangzhou, China^1

College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China^2

关键词: Gas-liquid-solid;    Multiphase model;    Separation efficiency;    Separation functions;    Separation mechanism;    Separation rate;    Shear-stress transport;    Three-phase separation;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/227/5/052032/pdf
DOI  :  10.1088/1755-1315/227/5/052032

学科分类：环境科学（综合）

来源: IOP

【 摘 要 】

In searching for a clearer vision and better understanding of the mechanism of the gas-liquid-solid separator in a UASB reactor, a 3-D CFD simulation code based on the Eulerian multiphase model with Shear Stress Transport turbulence model was adopted to evaluate the effects of overlapping rate of baffle plates on the separation of the three phases. In this approach, five (5) typical overlapping rate scenarios were investigated for a typical UASB reactor, and the flow pattern inside were visualised and analysed meanwhile. The results show that the averaged flow speed of three phases was doubled when they flew through the three-phase separator (TS) region, while obvious symmetrical vortexes and twisting flow patterns dominated in the TS region. The simulated characteristic circling flow pattern in the angled plate regions reveals a different separation mechanism of the TS, comparing the traditional theory accepted widely. Simulation investigation indicates that the baffle plate's overlapping rate of the typical TS was not the most important configuration and had insignificant influences on the gas-liquid-solid phases' averaged flow speed and separation efficiency among the five situations concerned in this article. This meant a more efficient arrangement of baffle's overlapping scheme could apply: a baffle's overlapping rate of 10% could achieve a separation rate as high as 99.1% for the gas-liquid-solid phases, while a reduction of 23.6% in the height occupation and a more 21.1% width of the TS could be optimized in this article case. On the other hand, the separation function of each layer of the typical TS was simulated and analysis could bring about some innovations for the widely used TS.