Formation experiments of CO2 hydrate chimney in a pressure cell

• Main Authors: Satsuki Kataoka, Osamu Kitamura, Kinji Hyakutake, Kiyoshi Abe, Akihiro Hachikubo, Hitoshi Shoji
• Format: Report
• Language: English
• Published: Kitami Institute of Technology/Kitami Institute of Technology/Kitami Institute of Technology/Kitami Institute of Technology/Kitami Institute of Technology/Kitami Institute of Technology 2005
• Subjects: CO_2 hydrate; gas hydrate chimney; bubble emission; supercooling(overpressure); gas supply rate; The Chimney; Nozzle; Polar meteorology and glaciology
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2987; http://id.nii.ac.jp/1291/00002987/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2987&item_no=1&attribute_id=18&file_no=1

Experimental investigations were conducted to understand the formation process of CO_2 hydrate the chimney structure by using a gas bubble emission technique in water within a pressure cell. The detailed process was video-recorded and analyzed to study the initiation and growth behavior of hydrate chimney while the cell pressure was increased and gas supply rate decreased gradually with time. In the initial stage of chimney growth, a hydrate crystal started to form in a cup shape at the gas nozzle and ascended together with gas bubbles due to mechanical weakness of the hydrate/nozzle contact. Growth of hydrate chimney occurred with supercooling of 3K(overpressure of 0.60MPa) or more, and continued until the top end was closed completely by hydrate.