Gas-Liquid Two-Phase Flow Characteristic Research on Micro Bubble Tubular Gas-Liquid Contactor

doi:10.12422/j.issn.1006-396X.2024.03.004

Abstract

Abstract:

Compared with the commonly used gas-liquid bubble tower, the tubular gas-liquid contactor has the advantages of high gas content rate, low energy consumption and simple maintenance to strengthen the gas-liquid mass transfer process by generating a uniform bubble-like and highly dispersed system in the pipeline space.A micro-bubble type tubular gas-liquid contactor was developed independently which utilizes the high-speed shear crushing effect of a venturi jet bubble generator to generate micro bubbles.Based on computational fluid dynamics (CFD) numerical simulation and indoor experiments,the bubble formation mechanism and bubble size distribution of the micro bubble tubular gas-liquid contactor were investigated.The results show that the VOF multiphase flow model coupled with RNG k-ε turbulence model can simulate the jet impingement process and bubble formation characteristics. In the expansion section of the venturi jet bubble generator,large bubbles are sheared and broken into micro bubbles, and the bubbles are uniform and stable. The particle size of bubbles decreases with the increase of liquid volume, and the particle size of bubbles is the smallest (76.5 μm) when the liquid volume is 14.0 L/min, the gas volume is the maximum natural suction volume, and the length of the column is 800 mm. The bubble particle size increases with the increase of gas volume, and is the smallest (86.7 μm) when the gas volume is 1.5 L/min, the liquid volume is 8.0 L/min, and the length of the column is 800 mm.As the length of column increases, the bubble size first decreases and then remains basically unchanged. When the column length is greater than 800 mm, its impact on the bubble particle size is relatively small.

Key words: Gas liquid contactor, Jet bubble generator, Micro bubble, CFD numerical simulation, Bubble size

摘要：

与常用气液鼓泡塔相比，管式气液接触器通过在管道空间内产生的均匀气泡状高分散体系强化气液传质过程，具有含气率高、能耗低和维护简单等优点。自主设计研制了带文丘里射流气泡发生器的微气泡型管式气液接触器；利用计算流体动力学（CFD）数值模拟和室内实验相结合的方法，对其所涉及的成泡机理、气泡粒径分布特性等进行了系统研究。结果表明，采用体积分数法（VOF）模型耦合RNG k-ε湍流模型可模拟分析微气泡型管式气液接触器内成泡机理和气泡形态；在文丘里射流气泡发生器的扩张段内可将大气泡剪切破碎成微气泡，且微气泡均匀稳定；气泡粒径随液体流量的增大而减小，在液体流量为14.0 L/min、气体流量为最大自然吸气量、柱体长度为800 mm时气泡粒径最小（76.5 μm）；气泡粒径随气体流量的增大而增大，在气体流量为1.5 L/min、液体流量为8.0 L/min、柱体长度为800 mm时气泡粒径最小（86.7 μm）；气泡粒径随柱体长度的增大呈现先降低后基本不变的趋势，当柱体长度大于800 mm时，其对气泡粒径的影响较小。

关键词: 气液接触器, 射流气泡发生器, 微气泡, CFD数值模拟, 气泡粒径

CLC Number:

TQ051.7

Hanyue YANG, Lingzhen KONG, Jiaqing CHEN, Huan SUN, Jiakai SONG, Biao KONG, Guodong DING. Gas-Liquid Two-Phase Flow Characteristic Research on Micro Bubble Tubular Gas-Liquid Contactor[J]. Journal of Petrochemical Universities, 2024, 37(3): 25-33.

杨寒月, 孔令真, 陈家庆, 孙欢, 宋家恺, 孔标, 丁国栋. 微气泡型管式气液接触器的气液两相流动特性研究[J]. 石油化工高等学校学报, 2024, 37(3): 25-33.

Figures/Tables 18

Fig.1 Structural schematic diagram of micro bubble tubular gas-liquid contactor

Fig.2 Schematic diagram of the structure of venturi jet bubble generator

Table 1 The main structural parameters of micro bubble tubular gas-liquid contactor

参数	数值
吸入室高度（h₁)/mm	20
吸入室直径(d₁)/mm	30
喷嘴直径（d₂)/mm	4
喉管长度（h₂)/mm	25
喉管直径（d₃)/mm	7
扩散段角度（α)/（°）	8
柱体直径（d₄)/mm	20
管式反应柱体长度/mm	400
管式气液接触器总长/mm	517

Fig.3 3D physical model and grid generation of micro bubble tubular gas-liquid contactor

Fig.4 Initial numerical simulation state setting of micro bubble tubular gas-liquid contactor

Fig.5 The variation curve of pressure drop on the central axis of micro bubble tubular gas-liquid contactor with grid number

Fig.6 Schematic diagram of indoor experimental process flow for micro bubble tubular gas-liquid contactor

Fig.7 Schematic diagram for measuring the particle size distribution of bubbles in a tubular reaction column

Fig.8 Cloud map of the volume fraction distribution of the liquid phase (MDEA) solution in the micro bubble tubular gas-liquid contactor

Fig.9 Cloud map of the velocity of mixed phase in the micro bubble tubular gas-liquid contactor

Fig.10 Flow characteristics of a portion of the central axis section of the venturi jet bubble generator

Fig.11 High speed camera images of bubbles in different positions of micro bubble tubular gas-liquid contactor

Fig.12 The variation curve of pressure drop with the different pumping rates under different measurement methods

Fig.13 The variation curve of particle size with the length of the tubular reaction column

Fig.14 High speed camera images of bubbles in the stable zone of a tubular reaction column under different pumping rates

Fig.15 Particle size distribution in the stable zone of a tubular reaction column under different pumping rates

Fig.16 The variation curve of particle size with the pumped liquid volume under different lengths of tubular reaction columns

Fig.17 The curve variation of particle size with suction rate under different lengths of tubular reaction columns

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