Abstract
In this study, we develop a numerical model based on Lattice Boltzmann (LB) method for simulating hydrate formation in brine, aiming at bridging the gap between microscopic mechanism and macroscopic experimental observations. The model employs convection-diffusion equations, coupled with salt exclusion and salinity-dependent hydrate formation kinetics, and is applied into an experiment of cyclopentane-hydrate formation in brine. Numerical simulation results indicate: 1) the predicted water conversion under wide salinity conditions can match well with experimental measurement and their deviations are less than 9%, much lower than the measurement error; 2) the salt exclusion by hydrate formation decreases the concentration of guest molecule and lowers the hydrate formation rate. The rapidly increased hydrate surface area offsets such effects of the enhanced salt concentration and promotes the rapid formation of the hydrate at the initial stage. Then, the constantly decreased concentration of guest molecule and enhanced concentration of the salt ions dominate the hydrate formation rate and gradually slow down the hydrate formation process; 3) the hydrate morphology significantly depends on guest molecule diffusion length. Comparatively, the effect of salinity on it is small and can be reasonably ignored. This LB model could have a potential application for analyzing the formation mechanism of oceanic hydrate and predicting the efficiency of hydrate-based desalination.
Published Version
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