Flows due to pressure induced dissociation-formation of gas hydrates

14th International Conference on Fluid Control, Measurements and Visualization

Agudo, J.R.^1 ; Kwon, S.^1 ; Saur, R.^1 ; Loekman, S.^2 ; Luzi, G.^1 ; Rauh, C.^3 ; Wierschem, A.^4 ; Delgado, A.^1,4

Institute of Fluid Mechanics, FAU Busan Campus, University of Erlangen-Nuremberg, Busan

46-742, Korea, Republic of^1

Institute of Chemical Reaction Engineering, FAU Busan Campus, University of Erlangen-Nuremberg, Busan

46-742, Korea, Republic of^2

Department of Food Biotechnology and Food Process Engineering, Technische Universität Berlin, Berlin

D-14195, Germany^3

Institute of Fluid Mechanics, University of Erlangen-Nuremberg, Erlangen

D-91058, Germany^4

关键词: Carbon dioxide hydrates;    Engineering applications;    Global climate changes;    Induced dissociation;    Molecular diffusion;    Scientific community;    Short induction time;    Transport phenomena;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/249/1/012018/pdf
DOI  :  10.1088/1757-899X/249/1/012018

来源: IOP

【 摘 要 】

During the last decade, Gas Hydrates (GH) have attracted the interest of the scientific community for engineering applications. Carbon dioxide hydrate (CO2H), for instance, may play an important role for capture and sequestration methods in order to reduce global climate change. Despite the extensive literature, the transport phenomena involved during CO2H formation are not yet fully understood. CO2transfer from gas or liquid phase to the bulk of water is expected to happen not only by molecular diffusion but also driven by natural convective currents induced by CO2dissolution in water. Using particle tracer methods, we experimentally characterize the flow velocity of the bulk of water during CO2H formation. For that purpose, CO2H is grown inside an optical cell with a volume of 12 mL at various pressures and temperatures. Due to CO2dissolution, convection currents are noticed prior to hydrate formation. Our experimental results point to a significant correlation between this process and the subsequent hydrate formation. Two well-differentiated hydrate growth patterns were observed depending on the hydrate induction time and the corresponding CO2concentration distribution inside water. For long induction times, CO2can be provided from the water phase resulting in rapid growth. Short induction times resulted in slow growth at the interface creating a solid barrier accompanied by a significant drop in the flow velocity. In some cases, the hydrate layer appeared to be unstable and convection could restart.