Design And Simulation Optimization Of Gradient-type Liquid-liquid Separator

The gravity separator has widely been used in the world with their unparalleled advantages and upgraded continuously during several decades.Especially the combination of gravity separation and coalescence technology,the efficiency of oil removal is greatly increased.At present,R&D of new style of oil/water separation has become a hot research field.In this article,FLUENT was used as the research tool to study the characteristics of the Gradient-Type Liquid-Liquid Separator(GTLLS).Grid generation software,GAMBIT was used to establish the physical model into related equipment in the simulation software FLUENT for simulations.According to the theory of fluid dynamics and the liquid-liquid phase separator,standard k-? turbulent model and multi-phase mixture model were adopted to simulate the flow field in the GTLLS.Analysis of the simulation results and optimization of the structural parameters were then carried out which offered necessary theoretical basis for the development and screening of the separator internal components.The three-dimensional numerical simulation of separator internal flow field was also performed using the previous work as reference.The results showed that: 1)Standard k-? model and multiphase mixture model are suitable for the1)Standard k-? model and multiphase mixture model are suitable for the simulation of the two-phase flow field inside the gradient-type liquid-liquid separator containing different internal components.2)The employ of the inlet structure not only reduces the impact of inlet flow on the interior flow field of the separator,but also makes the interior flow field distribution of the separator uniform and steady,up-down hole box-type inlet components has better flow properties and separation characteristics than the other two structures;groove steady flow structure has outstanding rectification and pre-separation effect.3)The coalescence components have a vital influence on the oil-water separation effect and the inclined plate coalescence structure has the better separation effect.4)The structure parameters of the separator have prominent influence on the separation effect of the gradient-type liquid-liquid separator.The plate angle(18°?24°?30°?42°)and plate length(300 mm?450 mm?700 mm?900 mm)of inclined plate were altered and the separation processes were simulated respectively.The result showed that the optimum values of the plate angle and plate length which are 24°and 700 mm respectively.In this article,the internal structures of the separator were studied through experiments;then the surface form of the inclined plate was investigated and the experiment study of the steady-flow components and coalescence components inside the separator was made.Finally,the operation parameters of the separator were discussed.The experiment results showed that:1)Steady-flow components has ameliorated the uniformity of the flow field and rectified the whole flow field;the employment of the coalescence components played an important role in increasing oil-water separation rate,especially the coalescence components of multilayer inclined plate.2)The retention time of the oil and water phase in the separator gets short and oil containing rate at oil outlet drops significantly with the increase of the inlet flow rate;oil volume fraction at oil outlet increases with the increase of oil-water ratio at inlet.