Experimental Study On Gas Phase Separation Performance Of Dualinlet Gas-liquid Cylindrical Cyclone

Gas-liquid Cylindrical Cyclone(GLCC),a new and efficient gas-liquid separator,is the key equipment for oil and gas separation in deep-sea oil and gas development.There has been a lot of research on GLCC,mainly focusing on the liquid phase separation performance,but less on the gas phase separation performance of the separator and the flow pattern in the lower cylinder of the GLCC,and the research objects are mostly single-inlet gas-liquid separators.The research on the double-inlet structure is not perfect,and there is a lack of research on the gas phase separation performance and the change and distribution of the gas-liquid flow pattern in the lower cylinder of the double-inlet GLCC.This paper focuses on the characteristics of gas-liquid flow pattern and gas phase separation performance in the lower cylinder of the double-inlet GLCC.The flow pattern transformation and distribution in the liquid phase space are observed by using the experimental method,and the variation laws of gas-phase separation efficiency under different inlet structures,different gas-liquid flowrates and different liquid-phase media were compared and analyzed.The main conclusions are as follows:(1)When the liquid medium is water,the change of the flow pattern of the lower cylinder of the double-inlet GLCC is mainly affected by the liquid flow rate,which is divided into three categories: no gas core,unstable gas core and stable gas core.Under the stable gas core flow pattern,gas void fraction in liquid outlet pipe is the lowest.The swirl intensity of the double-inlet structure is greater than that of the single-inlet structure,the gas core states are widely distributed,and the bubbles are brought out more axially.(2)The inlet structure affects the gas phase separation efficiency of GLCC.The separation efficiency of the two dual-inlet structures has its own advantages under different operating conditions;in the case of high-viscosity liquid medium,the dual inlet GLCC with upward opening is superior to the dual inlet GLCC with downward opening.The separation performance of single-inlet GLCC is better than the dual inlet GLCC.(3)In the same structure of GLCC,gas-liquid flow rate and liquid medium viscosity are important factors affecting the gas phase separation efficiency.Under the dual inlet GLCC with upward opening,increasing the flow rate of the gas is beneficial to the separation of bubbles;with the increase of liquid flow rate,the separation capacity is enhanced,but at the same time,the axial carrying capacity of liquid is enhanced,and the rate of gas phase carried out is increasing,and the gas void fraction depends on the combination of the separation capacity and the axial carrying capacity of liquid.As the viscosity of liquid medium increases,the swirl intensity decreases,but the axial carry-out decreases.(4)Without considering glycerite,dimensionless parameters were introduced and the experimental data were fitted to establish a prediction model of bubble carry-out of the dual inlet GLCC with upward opening.The calculation error of the formula was within 25%.