Influence of Direct Current–Voltage Accompanied by Charge Flow on CO2 Hydrate Formation

The capture and storage of carbon dioxide (CO2) are urgent and crucial to achieve the goal of carbon neutrality. Hydrate-based CO2 capture technology is one of the promising technologies for capturing and storing CO2. This work studied the nucleation and growth of CO2 hydrate provoked by direct current–voltage accompanied by charge flow with the agitation of 450 rpm at an initial pressure of 3.5 MPa and a temperature of 274.15 K. The results show that the physical bubble behavior and electrochemistry mechanisms could influence CO2 hydrate formation process in the application of voltage. The induction time and semi-completion time of CO2 hydrate formation were decreased by 51% and 27.8% in the presence of 15 V, respectively. However, more product of electrolysis, Joule heat and ions, could inhibit the CO2 hydrate formation process in the application of a high voltage (60 V). In addition, a high voltage (60 V) could change the morphology characteristics of CO2 hydrate from gel-like to whisker-like. This study provides valuable information on the formation of CO2 hydrate under the action of charge flow.

Bubble behavior in liquid-gas two-phase flow behind a cross-shaped obstacle in a vertical circular duct

Grid spacers installed in subchannels of fuel assemblies for nuclear reactors can promote heat transfer. However, the fluid velocity and bubble behavior are greatly affected as the cross-sectional area of the flow passage changes. Therefore, the void fraction distribution behind the obstacle that simulates the grid spacer shape simply was measured by using a wire mesh sensor (WMS) system. Moreover, a two-phase flow analysis was performed to investigate the effect of the obstacle on the bubble behavior in a vertical duct.