Modelling of hydrate dissociation in multiphase flow considering particle behaviors, mass and heat transfer

Abstract

In this study, a hydrate slurry multiphase flow model coupled with particle dissociation and behaviors is developed. Based on intrinsic dissociation kinetic theory, the hydrate dissociation model is improved by considering the effect of mass & heat transfer and particle size evolvement. The two-way influence mechanisms among multiphase flow, dissociation and particle behaviors are analyzed. The experimental results are used to validate the model efficiency. The flow characteristics with particle behaviors and dissociation rate under different hydrate volume fractions and flow velocities are investigated. The results indicate that the hydrate particle size grows due to agglomeration and then arrives at a balanced state with intensification of breakage effect. Higher hydrate volume fraction can increase the mean particle size, further increasing the slurry viscosity and pressure drop. The gas bubbles generated by dissociation prompt the transportability of hydrate slurry, reducing the pressure loss. The dissociation rate increases first and gradually declines because of the hydrate surface area reduction induced by particle agglomeration. The results can contribute to the application of hydrate slurry-based transport technologies and relevant modelling studies of multiphase flow with phase change.