Numerical Simulation Analysis On The Operating Characteristics Of Internal Components In Gravity Oil/Water Separator

Gravity oil/water separator is one of the most basic equipment in oil/waterseparation process, and its separation effect has a significant influence on downstreamengineering processes. The aim of this paper is to study the internal components’influences on the flow field in horizontal gravity oil/water separator by numericalsimulation using Fluent software and provide technical backgrounds for the designingof separator.First, inlet distributor with round orifices and five commonly used inletcomponents were compared for the flow pattern in gravity oil/water separator. It turnsout that the flow pattern produced by inlet distributor with round orifices achieveshorizontal plug flow within the smallest distance. Response surface method (RSM)was applied to obtain the optimum structural parameters of the inlet distributor. Theresult shows that the relative axial velocity unevenness (Mf) varies with the change ofthe ratio of total round orifices area on inlet to the cross section area of the separator,P1, the orifices area ratio of hemispherical seal head to cylindrical side face, P2, andthe ratio of distance between side face orifices and head seam to D (D=the diameterof the separator), P3, and was influenced by the interactions of P1, P2, P3, Mfthroughthe cross section at0.6D from the inlet reaches the minimal value, when P1, P2, P3are0.0857,0.0988and0.0360respectively.The movement of dispersed oil droplets in the separator was simulated bydiscrete phase model (DPM). By comparing the droplets’ tracks, a conclusion can bedrawn that the separation efficiency increases with the increasing of the diameter andresidence time of oil droplets.The influences of flow-stabilizing component and coalescence component onflow were analyzed by numerical simulation. It is showed that in the separatorcontaining inlet distributor with round orifices:(1) when “Tian” Character shapedflow-stabilizing component is situated at0.54D, Mfthrough the cross section at0.6Dreduce to the minimum;(2) leaving out the coalescence characteristic, parallel plateinterceptors (PPI) produces the smallest Mf, providing the proper circumstance for theupward floating motion of oil droplets.