X-ray Imaging of Clathrate Hydrates as Gas Storage Materials: Absorption Contrast of Low-Density and Low-Absorption Materials Using Energy-Dependent X-ray Computed Tomography
Satoshi Takeya, Sanehiro Muromachi, Akio Yoneyama
Abstract
Non-destructive observations are useful for analyzing objects embedded in structures, but characterizations of low-density materials co-existing with liquid water or ice are difficult, owing to insufficient contrast produced by X-ray computed tomography (CT). This study demonstrates the contrast between the absorption contrast X-ray images of clathrate hydrates and water as a function of the X-ray energy using monochromatic X-rays. Quantitative characterization of the contrast change in the absorption contrast X-ray CT of resins and clathrate hydrates indicates that X-ray CT measurements using monochromatic X-rays are advantageous for the segmentation of carbon dioxide hydrates co-existing with ice but not for methane or tetrahydrofuran hydrates. This can help in the application of absorption contrast X-ray imaging to previously challenging three-dimensional (3D) studies on gas storage processes in materials, such as shale or active carbon, based on their macroscopic 3D structures.