Direct Numerical Simulation of Hydrate Dissociation in Homogeneous Porous Media by Applying CFD Method: One Example of CO2 Hydrate

Abstract

Computational fluid method (CFD) is popular in either large-scale or meso-scale simulations. One example is to establish a new pore-scale (m~μm) model of laboratory-scale sediment samples for estimating the dissociation rate of synthesized CO2 hydrate (CO2H) reported by Jeong. It is assumed that CO2H formed homogeneously in spherical pellets. In the bulk flow, concentration and temperature of liquid CO2 in water flow was analyzed by CFD method under high-pressure state. Finite volume method (FVM) were applied in a face-centered packing in unstructured mesh. At the surface of hydrate, a dissociation model has been employed. Surface mass and heat transfer between hydrate and water are both visualized. The initial temperature 253.15K of CO2H pellets dissociated due to ambient warm water flow of 276.15 and 282.15K and fugacity variation, ex. 2.01 and 1.23 MPa. Three tentative cases with porosity 74, 66, and 49% are individually simulated in this study. In the calculation, periodic conditions are imposed at each surface of packing. Numerical results of this work show good agreement with Nihous’model. Kinetic modeling by using 3D unstructured mesh and CFD scheme seems a simple tool, and could be easily extended to determine complex phenomena coupled with momentum, mass and heat transfer in the sediment samples.