Design Optimization of a Rotary Gas Separator in ESP Systems

摘要

This paper presents the optimization study of a rotary gasseparator (RGS) in ESP systems by improving theperformance of the inducer part of the RGS. Using two-phaseflow inducer model, sensitivity studies were performed tothree inducer blade geometrical variables, i.e., tip diameter,pitch length, and total number of pitch, to evaluate theinducer performance in terms of head generation and gashandling capacity.These studies show that the inducer performance issensitive to the blade tip diameter and pitch length.Increasing the blade tip diameter and pitch length enlargesthe inducer cross sectional area, which in turn increasing theliquid deceleration. This mechanism is responsible forincreasing the head generated by the inducer and thesustainability of the inducer in handling free gas. Thesestudies also indicate that increasing the total number of pitchcauses detrimental effect to the inducer performance.These findings suggest that the tip diameter should bemade as large as possible within the tolerable size of thepump housing. Similarly, the pitch length should be extendedas long as possible within the mechanical integrity toleranceof the whole RGS assembly.The implementation of the inducer performancesensitivity study results on a typical 400 series RGS indicatesthat the RGS performance can be improved by enlarging theinducer blade tip diameter and the pitch length. However, theimprovement becomes marginal as the gas-liquid ratioincreases, which might indicate the limitation of the 400series RGS application.