Research On Gas-Liquid Cylindrical Cyclone Separator Based On Flow Pattern Control

The compact gas-liquid separator has been widely used in oil and gas fields at home and abroad due to its small size,low cost and easy installation and maintenance.However,owing to the narrow separation space,it is difficult to buffer the large gas-liquid flow fluctuations from the inlet,so the separation efficiency deteriorates,especially under the impact of the slug flow pattern.Therefore,based on the downward-inclined straight tube rectification structure of the gas-liquid cylindrical cyclone separator,this paper uses numerical simulation methods to study the fluctuation of the liquid holdup at the exit of the spiral tube rectification structure,and explore the flow law and dissipation characteristics of the liquid slug in the spiral tube.And to study the influence of the structural difference of the rectifier tube on the separation and stability of the gas-liquid cyclone in the separator cylinder.The main research contents and conclusions are as follows:This paper establishes a one-dimensional steady-state slug flow model,and writes a custom UDF function of CFD simulation software to define the initial conditions of transient slug flow.Based on the VOF multiphase flow model,the gas-liquid interface is captured,and the dissipation characteristics of the slug flow in the spiral tube rectification structure are simulated.Structural parameters such as the downward angle,the spiral diameter,the expansion ratio,the spiral length,and the expansion position of the rectification structure are analyzed.The influence of flow parameters such as the apparent flow velocity of the liquid slug and the length of the liquid slug on the dissipation rate of the liquid slug and the effect of the gas-liquid two-phase separation in the separator are also analyzed.What is more,this paper is based on the minimum expansion ratio of 1.67 in the rectifying structure.It is preferable that the downward inclination angle of the spiral is-24°,the maximum spiral diameter is 400mm,and the minimum Spiral inlet rectifier tube structure with 0.87 turns.Considering the mutual influence of the inlet rectifying section and the cylindrical swirling section,the author explores the influence of the structural parameters of the spiral tube rectifying part and the cylindrical body on the gas-liquid separation efficiency in the separator cylinder.From the analysis of the phase distribution,velocity distribution and stability in the cylinder,the optimal separator structure size is selected.The fact is that the cylinder diameter is 116mm,the upper cylinder height is 1m,the lower cylinder height is 1.4m,and the inlet groove area is 5.6494×10^-4m².Based on the simulated and optimized spiral tube dissipation structure,a transparent experimental prototype is designed and processed.Under the same flow parameters of the inlet flow,the two types of rectifying structure of the gas-liquid cyclone separator,that is,the downward-inclined straight pipe and the spiral pipe,are compared at the first place.Besides,the influence factors of the pipeline pressure,the liquid holdup of the tangential inlet section and the position of the equilibrium liquid level in the cylinder are studied.Last,the author explores the influence of different parameter conditions on the separation efficiency of the separator.By comparing the straight downward pipe and the downward spiral pipe,the author finds that the pressure at the outlet of the spiral pipe fluctuates greatly,while the liquid holdup at the tangential inlet of the spiral pipe is smaller,and the gas-liquid interface fluctuates smoothly,and the peak value of the liquid holdup curve decreases 50%,both fluctuate around0.2.For the liquid phase valve and the gas phase valve,the relative equilibrium liquid level in the cylinder corresponding to the spiral downward inclined pipe is higher.Under the same valve opening,the balance liquid level corresponding to the spiral tube is relatively high,and the operation range of the operation is relatively wide.The liquid plug dissipation and gas-liquid separation efficiency of the spiral tube rectification structure is obviously better than that of the down-dip straight tube,which has important guiding significance for the design and application of the gas-liquid cylindrical cyclone separator.