Effect of multi-stage cooling on the kinetic behavior of methane hydrate formation in sandy medium

Abstract

Methane hydrates (MHs) have been considered as one of the future energy resource due to its abundant resource volume of CH4 in nature (~3,000 trillion cubic meter) and its capability to store CH4 efficiently. Recovering energy from MHs requires a profound understanding of the heat transfer, fluids flow and phase change behavior of MHs during its formation and dissociation processes. To form MH-bearing sediment in laboratories mimicking naturally occurring MHs is universally challenging due to the limitations on the dimension of reactor, location and rate of the cooling as well as the kinetic rate of MH formation reaction. In this study, we investigated the kinetic behavior of MH formation in sandy medium using multi-stage cooling processes with the objective to form a spatially-homogeneous MH bearing sediment. We found that under the excess-water environment using a three-stage cooling (15 °C 10 °C 5°C 0.8 °C) or a two-stage cooling (15 °C 8 °C 0.8 °C) process retards the MH formation rate, and results in a more homogeneous spatial distribution of hydrate in reactor than a fast one-stage cooling (15 °C 0.8 °C) process. This study provides new insight on how to devise new strategy to form MH bearing sediment in laboratory with the desired spatial distribution of hydrate phase. © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of ICAE2018 - The 10th International Conference on Applied Energy.