The investigation on the mechanism of efficiency enhancement for hydrogen production by water electrolysis with magnetic field

• Main Authors: Ching-hung Wu, 吳慶鴻
• Other Authors: Lih-wu Hourng
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/45200333678353809467

碩士 === 國立中央大學 === 能源工程研究所 === 102 === As water electrolysis is conducted with an electric field perpendicular to a magnetic field, Lorenz force will produce magnetohydrodynamic (MHD) convection and affect the gas bubble evolution. This experiment uses nickel as electrodes, and the potassium hydroxide electrolyte concentration is 25wt%. Potentiostat and high-speed camera are used to record the bubble evolution. The upward Lorentz force can accelerate the speed bubbles to leave the surface of the electrode, which lowers the electrochemical polarization. Therefore, from the bubble behavior shown in the picture. We observe that all the bubbles will be speeded under the action of Lorenz force for different electrode distances and current densities. However, the coverage of bubbles is reduced. The biggest bubble on the electrode surface is smaller. The bubble diameter of the maximum amount of bubbles distribution is smaller. Bubble flow rate can be obtained by combing the bubble speed and coverage. In a upward Lorentz force, the electrode distance 2 mm and current density 0.3 A/m^2, the flow rate increases about 67.8%. While it is about 42% for the electrode distance 5 mm and current density 0.3 A/m^2. The economic power efficiency was also saved a little. Water electrolysis is a commonly used method to produce Hydrogen. Magnetic field does not need to consume additional energy. However, it can increase hydrogen production efficiency and reduce energy consumption. Water electrolysis adds magnetic field has development potential in the future.