New Simulator for Gas–Hydrate Slurry Stratified Flow Based on the Hydrate Kinetic Growth Model

Abstract

A new simulator for gas–hydrate slurry stratified flow is presented, which can simulate the flow characteristics, including gas/liquid velocity, liquid holdup, and pressure drop. The simulator includes an inward and outward hydrate growth shell model and two-phase flow hydrodynamic model. The hydrate growth model systematically considers the kinetics and limitations of hydrate formation, namely, the mass– and heat–transfer. The two-phase flow hydrodynamic model is composed of mass and momentum equations for each phase as well as energy balance equations considering the heat generation related to hydrate formation. Thereafter, an inclined pipeline case is simulated using the simulator. The results demonstrate that, once the kinetic requirements for hydrate crystallization are satisfied, hydrates form rapidly during the initial stage and the hydrate formation rate then decreases owing to the limitation of the mass– and heat–transfer. Meanwhile, the hydrate states (formation onset time, formation rate, and volume fraction) as well as flow characteristics of a multiphase system are obtained, providing acceptable results for engineers in the field. Sensitivity analyses of the key hydrate growth shell model parameters are implemented, and the results indicate that the influences of diffusivity and initial water droplet size on the hydrate formation rate are greater than the of the porous parameter.