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膜生物反应器内气液与污泥三相流动的数值模拟

作者：李会强，刘峤，王青，徐农，董强，丁爱琴，范茏

单位： 1合肥学院，能源材料与化工学院，合肥 230601；2中国科学院过程工程研究所，生化工程国家重点实验室，北京 100190；3南京工业大学，材料化学工程国家重点实验室，南京 211816

关键词：气-液-污泥三相流；计算流体力学；膜生物反应器；污泥沉降

DOI号：

分类号： TQ028.5, O359

出版年,卷(期):页码： 2023,43(2):138-149

摘要：

将污泥作为独立的一相，对膜生物反应器内气-水-污泥三相流动进行计算流体力学模拟，不仅得到反应器内流体力学特性和气体分布，还获得污泥的流动与沉降特性，分析了易发生污泥沉降造成膜污染的区域。探讨了曝气气泡大小、曝气面积及曝气位置的影响，以期获得减小膜污染的最佳操作条件，优化反应器的结构设计。在本研究范围内，当曝气管距离膜单元底面350 mm，曝气面宽度2 mm，且气泡直径为4-6 mm时，污泥沉积导致膜污染的风险最小。由于膜生物反应器内气-水-污泥三相流动的数据较少，为了验证，将水与污泥的混合物简化为液相，进行气-液两相流动的模拟，并与文献的两相模拟结果比较，二者吻合较好，证明本模拟方法和结果的可靠性。

The gas-water-sludge three-phase flow in an aerated membrane bioreactor (MBR) is simulated using computational fluid dynamics software FLUENT. The activated sludge is treated as a single phase. Not only the flow and the distribution of gas in the reactor are obtained, but also the hydrodynamics and settling characteristic of sludge are presented. The possible area for sludge settling, i.e. the consequent membrane pollution area, is provided. Furthermore, the effects of aeration bubble diameter, aeration area, and aeration location on the flow and sludge sedimentation are investigated. Both the operation conditions and the reactor structure are optimized to minimize membrane pollution. In the simulated range, the potential to have membrane fouling is minimal when the distance between the aeration surface and the bottom of the membrane unit is 350 mm, the width of the simplified aeration surface is 2 mm, and the bubble diameter is between 4-6 mm. Since the data for gas-liquid-solid three-phase flow in MBR are scarce, the gas-liquid two-phase flow is simulated for the purpose of verification. The mixture of water and sludge is treated as one single liquid phase. The comparison of two-phase simulation with literature proved the reliability of the simulation method and results.

基金项目：

安徽省重点研究和开发计划项目（2022a05020041）；安徽省教育厅重点项目（KJ2021A1015，KJ2020A0669）；中国科学院过程工程研究所生化国家重点实验室开放基金项目；南京工业大学材料化学工程国家重点实验室开放基金项目（KL21-04）。

作者简介：

李会强（1996—），男，安徽霍邱人，硕士研究生，研究方向为计算流体力学。E-mail：lhqstu127@163.com

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