ABSTRACT

The research studied the modeling of a multiphase downward flow in a vertical pipe using CO2-kerosene-water flow system. The objective was to characterize the transport CO2 for further application to carbon capture and sequestration in a three-phase downward flow in a vertical pipe. The study developed an experimental test bed integrated with a high speed video camera to record the observed flow patterns, and the pressure drops across the length of the vertical pipe. The three-phase flow characteristics were studied at 25°C for the measured range of water and oil velocities from 0.008889 to 13.0734m/s at different water cuts (WCs) of 20, 50, 70 and 90%. Equally, the CO2 phase velocity was varied for the measured values from 0.452 to 32.868m/s to cover a wide range of the developed flow patterns. The results developed a flow pattern map of the flow system, and obtained the homogenous flow model calculated pressure drop of 336.75N/m3 at a lowest gas superficial velocity for 20% WC; while the largest value was obtained at 4570.431N/m3 for 90% WC at the highest value of the superficial gas velocity. Additionally, a drift-flux flow model was developed to study the effect of gas velocity for the experimental multiphase system. The analysis of the simulated model result showed that the values of the pressure drops increased as the gas velocity and the WCs were increased. Also, the gas flow film thickness was found to increase from 0.011m, due to high interfacial force observed in the developed bubble/slug flow, to 0.02362m for all studied WCs; where the lowest and highest values were experienced at 90 and 20%WC. Consequently, the transition criterium from one flow pattern to another was established as a function of the gas film thickness (radius) and superficial velocity; where the developed flow patterns revealed a strong dependence on the interfacial forces among the phases when compared to the pipe wall shear force for all studied WCs of the flow system. Hence, the effect of the CO2 gas phase on the total pressure drop of the studied multiphase flow pressure was averaged at 20% for all WCs, with an exception at 90% WC due to the full liquid phase inversion occurrence in the flow system. However, the comparative analysis of the pressure drops calculated from the two mathematical approaches revealed on the average an over-prediction of 8.685% for the drift-flux flow model and 12.981% under-prediction for the homogenous flow model for all WCs; where the initial demonstrated similarities with other models in open literature.     These preceding inferences generally provided an adequate understanding for further application of the studied flow system modeling technique to carbon capture and sequestration.