新型气液分离闪蒸撬分液侧内流场模拟研究

Numerical Study on the Internal Flow Fluid of the Gas-Liquid Separation Unit in a New Skid-mounted Device with Gas-Liquid Separation and Flash Distillation

为进一步探究气液分离闪蒸撬分液侧内部构件对其分离性能的影响规律,提高分液侧分离效率,基于标准k–ε模型和欧拉–欧拉方法,建立了分液侧流体流动特性分析模型,对分离腔内流场进行了数值模拟,将结果与文献实验数据进行了模拟对比,验证了模型的准确性,优化分析了分液侧内部构件结构参数对分离性能的影响。分析了分离腔内连通管、捕雾器、导流板及折流板结构参数对分液侧分离效率的影响,得出连通管对于分液侧整体分离效率影响很大,其直径和分布位置变化都会引起分离腔内流体的扰动;捕雾器厚度的增加会提高对于微小液滴的捕集作用,而其直径对分离效率影响较小。导流板主要影响入口流体的速度大小,改变其深度和角度均使得分离效果变化明显;折流板主要起到整流作用,其结构尺寸对分离效果影响很小。优化了分液侧分离腔内部的结构参数,结果表明:分离腔与集液筒之间至少要有两根连通管,并分别布置于分离腔的积液区和气相区,可以有效提高分离腔排液,避免集液筒发生气塞现象;当捕雾器厚度在60~120 mm时,分液侧分离效率波动很小,其整体分离效率可高达98%以上;导流板角度在90°~135°,深度在385~647 mm范围时,分离腔内部积液区流体流速较小,排液顺畅,分离效率提高。研究成果为新型气液分离闪蒸撬分液侧结构参数设计提供了理论依据。

To further investigate the influence of internal components on separation characteristics of a gas–liquid separation unit in a new skidmounted device with gas–liquid separation and flash distillation,based on standard k–εturbulent model and Eulerian/Eulerian approach,the CFD method was performed to establish a numerical simulation model of flow characteristic on the separation chamber to improve it’s simulation efficiency.The simulation results were compared with the experimental measurements to verify the accuracy of the model,and the internal components’structural parameters were optimized.The analysis of the influence of communicating pipes,demister,deflector,baffle plate on separation efficiency,showed that the number and location of communicating pipes can lead the fluid in the separation chamber disturbance.With the thickness of the demister increasing,the trapping effect of the droplets is enhanced,while the diameter of which has little influence upon separation efficiency.The deflector mainly affects the velocity of the inlet fluid,when it’s depth and angle changed,the separation ability changed significantly.The baffle,mainly rectifing the fliud flow,has little effect on the separation effect.Through the optimization of internal components’structure on the separation chamber,liquid in separation chamber can be discharged smoothly into the cylinder,and also avoid the cylinder air lock when the number of communicating pipes are more than two and distribute in the liquid and gas regions of the separation chamber,respectively.The separation efficiency of gas–liquid separation unit will reach 98%when the demister at a thickness of 60 mm to 120 mm.When the deflector at an angle of 90°to 135°and a depth of 385 mm to 647 mm,the slow flow in liquid regions of separation chamber leads to the drainage smooth,and the separation efficiency can be improved.The above results will provide theoretical guidance for the optimization and design of structural parameters on gas-liquid separation unit in a new skid-mounted device with gas-liquid separation and flash distillation.