EFFECT OF DRAG-REDUCING AGENTS IN MULTIPHASE FLOW PIPELINES

The effect of drag-reducing agents (DRA) on pressure gradient and flow regime has been studied in horizontal and 2-deg upward inclined pipes . Experiments were conducted for different flow regimes in a 10-cm i.d ., 18-m long plexiglass system. The effectiveness of DRA was examined for concentrations ranging from 0 to 75 ppm. Studies were done for sup erficial liquid velocities between 0.03 and 1.5 m/s and superficial ga s velocities between 1 and 14 m/s. The results indicate that DRA was e ffective in reducing the pressure gradients in single and multiphase f low. The DRA was more effective for lower superficial liquid and gas v elocities for both single and multiphase flow. Pressure gradient reduc tions of up to 42 percent for full pipe flow 81 percent for stratified flow, and 35 percent for annular flow were achieved in horizontal pip es. in 2 deg upward inclination, the pressure gradient reduction for s lug pow, with a concentration of 50 ppm DRA, was found to be 28 and 38 percent at superficial gas velocities of 2 and 6 m/s, respectively. F low regimes maps with DRA were constructed in horizontal pipes. Transi tion to slug flow with addition of DRA was observed to occur at higher superficial liquid velocities.