THz electromagnetic wave regulated dissolution of methane hydrate

Abstract

Methane hydrate (so-called flammable ice) has many advantages such as wide distribution, large resource reserves, high energy density, being clean and pollution-free, etc. Thus, it has attracted much attention since it was discovered. Unfortunately, its exploration encounters many difficulties, which involve mainly with the dissolution process of caged methane hydrate. Therefore, in this work the specific effect of THz electromagnetic wave on decomposition of the hydrate is explored through molecular dynamics simulations. Analyzing the vibrational spectrum of the hydrogen-bond network in methane hydrate, no specific absorption peak is found in the bulk water. Applying a THz wave at this specific frequency to the methane hydrate, the original hydrogen-bond network is broken, the coordinate number of water molecules for the methane decreases, and ultimately the methane frees from the water cage. The <i>F</i>₄ ordered parameters further validate the phase change from the crystal water to liquid water under the same THz field irritation. It is also proved that this peak absorption frequency has a remarkable superiority over other frequencies in decomposing the methane hydrate, hence it has specificity. Our findings support the feasibility of non-thermally dissolving methane hydrate, which promises to promote the exploitation efficiency and development of new energy sources in the future.