The purpose of the present investigation is the analysis of the solidliquid- gas mixture flow in the airlift system that is used to recovery Methane-Hydrate (MH) from the seabed. In this paper, as the first step, we calculated unsteady gas-liquid two-phase flow in single-dimension using a numerical procedure based on finite method. And we experiment decomposition rate of Gas Hydrate by using R141b- Hydrate instead of Methane Hydrate. From calculation and experiment, we investigate the possibility of airlift for using the recovery system of Methane Hydrate from deep sea.


Our modern life is supported by massive energy consumption. And in the 20th century, oil became the main source of energy. However, it is considered that stocks of oil will last for a few decades. Methane hydrate (MH) that exists a lot around Japan and all over the world may be alternative energy resources. And we have established a recovery system of methane hydrate from deep sea. We considered that airlift system was the most effective way for the recovery system of methane hydrate. Fig.1 shows the conceptual figure of airlift system. A pipe inserted into the MH layer that exists in the seabed and gas is blown into middle of the pipe. Then a rising flow occurs in the pipe, and the solid MH is sucked up to the sea surface by the rising liquid flow. The MH will dissolve and gasify with passing through the pipe due to increasing temperature and decreasing pressure, as it approaches the sea surface. The injection gas quantity may reduce by the effect of this methane gas. The effect of this phenomenon is called self-air-lift effect. However, the optimum position of the gas injection point and the gas mass flow rate has not been found yet.

This content is only available via PDF.
You can access this article if you purchase or spend a download.