Multiphase flow splitting in looped pipelines

Abstract

A novel and unique experimental facility was design, constructed and instrumented, enabling slug flow splitting data acquisition in both parallel and looped lines. A total of 81 experimental test runs were carried out for various superficial gas and liquid velocity combinations. Uneven split conditions data were acquired by utilizing either a choke valve on one of the lines or different pipe diameters. For the symmetrical configurations of both parallel and looped equal diameter lines, the phases split equally in the lines. When the parallel and looped lines are of different resistance to flow (utilizing a choke installed on one of the lines or different line diameters), uneven split of the phases occurs. The gas-phase flows preferentially into the smaller resistance line. This results in different gas–liquid ratios in the two lines, which are different from the gas–liquid ratio at the inlet. A mechanistic model has been developed for the prediction of the uneven gas and liquid splitting and the pressure drop in two-phase looped lines. Good agreement is observed between the model predictions and the experimental data, with an average error of about 15 % in the phase splitting and pressure drop.