EXPERIMENTAL STUDIES ON VELOCITIES OF GAS- AND SOLID-PHASES IN GAS-LIQUID-SOLID THREE-PHASE FLOW FOR SUBSEA RESOURCE PRODUCTIONS

Subsea minerals and methane hydrates have been found in the deep-sea within Japan's exclusive economic zone, but they have not been commercialized owing to technical issues. Gas-lift pumping is a promising technique for transporting subsea minerals and methane hydrates from the seafloor to the surface. However, the internal flow within the pipes of a gas-lift pumping system often becomes a three-phase flow, so a method is needed for calculating the velocity of each phase. We reviewed previous studies on the velocities of each phase in two- and three-phase flows, which we used to propose correlations for the velocities of the gas and solid phases.We then conducted experiments on gas-liquid two-phase and gas-liquid-solid three-phase flows through transparent polyvinyl chloride pipes using glass beads as solid particles. The experimental data suggests that the presence of the solid phase has little influence on the distribution parameters and drift velocity. In addition, the velocity of the liquid phase has a large influence on the velocity of the solid phase for the slug flow, and the velocity of the gas phase has a large influence on the velocity of the solid phase for the annular flow. We use the proposed correlations to calculate the velocities of each phase in a threephase flow and compare the results with the experimental data. The comparison shows that the proposed correlations can accurately calculate the velocities of the gas and solid phases.