Liquid film flow and separation characteristics in the swirl separation section of a tubular deliquidiser

doi:10.16085/j.issn.1000-6613.2024-0437

Abstract

Abstract:

The flow characteristics of the liquid film in the cyclone section of the tubular deliquidiser are the key factors affecting the separation performance. It is very important to understand the relationship between liquid film flow and separation efficiency for structure improvement and performance improvement. In this paper, the factors such as liquid-gas ratio, inlet gas velocity, split flow ratio and outlet angle of swirl blade and so on were changed to obtain the high-speed photographic images and separation efficiency of liquid film flow under different operating conditions by carrying out laboratory experiments. The image analysis method of the velocity and angle of the surface wave of the liquid film was established based on Matlab programming to determine the relationship between the flow characteristics of the liquid film and the separation efficiency. The results showed that when the liquid-gas ratio was in the range of 0.12—0.3L/m³, the effects of liquid-gas ratio and split flow ratio on the separation efficiency and the surface wave velocity of liquid film were not obvious. The inlet velocity had the most significant effect on the separation efficiency and liquid film surface wave velocity. With the inlet velocity increasing gradually, the separation efficiency increased first and then decreased, and the inflection point occurred at the inlet velocity of 18.82m/s. The separation efficiency was 30°>45°>60° from large to small, and the surface wave velocity of liquid film was 60°>45°>30° from large to small, when the exit angle of swirl blade was 30°, 45° and 60°, respectively. In general, the critical value of liquid film surface wave velocity in the swirl separation pipe segment was 0.98m/s, and when the liquid film surface wave velocity was greater than this value, the liquid film was more likely to break at the liquid outlet of the annular gap, and some of the broken large droplets entered the gas phase outlet under the action of gravity and air flow, resulting in a significant decline in gas-liquid separation efficiency. When the surface wave velocity of liquid film was less than 0.98m/s, the separation efficiency was basically kept above 98%.

Key words: gas-liquid separation, liquid film flow characteristics, film surface wave velocity, separation efficiency

摘要：

脱液型管式气液分离器旋流分离段内液膜流动特性是影响分离性能的关键因素，掌握液膜流动与分离效率之间的关系对结构改进和性能提升至关重要。本文改变液气比、入口气速、分流比和旋流叶片出口角等因素开展室内实验测试，获得不同工况下液膜流动的高速摄影图像和分离效率，基于Matlab编程建立液膜表面波速度和角度的图像分析方法，确定液膜流动特性与分离效率之间的关系。结果表明，液气比在0.12~0.3L/m³范围内，液气比和分流比对分离效率和液膜表面波速度的影响不明显；入口气速对分离效率和液膜表面波速度的影响最为显著，随着入口气速逐渐增加，分离效率先增大后减小，在入口气速18.82m/s时出现拐点；旋流叶片出口角分别为30°、45°、60°时，分离效率由大到小依次为30°>45°>60°，液膜表面波速度由大到小依次为60°>45°>30°。总的来说，旋流分离管段内液膜表面波速度0.98m/s为临界值，液膜表面波速度大于该值时，环缝排液口处液膜更易发生破碎，部分破碎的大液滴在重力和气流作用下进入气相出口，导致气液分离效率显著下降；液膜表面波速度小于0.98m/s时，分离效率基本保持在98%以上。

关键词: 气液分离, 液膜流动特性, 液膜表面波速度, 分离效率

CLC Number:

TQ021.1

SONG Jiakai, KONG Lingzhen, CHEN Jiaqing, SUN Huan, LI Qi, LI Changhe, WANG Sicheng, KONG Biao. Liquid film flow and separation characteristics in the swirl separation section of a tubular deliquidiser[J]. Chemical Industry and Engineering Progress, 2024, 43(8): 4297-4306.

宋家恺, 孔令真, 陈家庆, 孙欢, 李奇, 李长河, 王思诚, 孔标. 脱液型管式气液分离器旋流分离段内液膜流动和分离特性[J]. 化工进展, 2024, 43(8): 4297-4306.

Figures/Tables 21

References 22

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