Technology of China’s largest electrolyzer – 400kA large-scale pre-baked anode aluminum electrolyzer

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The 400kA large-scale pre-baked anode aluminum electrolyzer technology, developed by China Aluminium Corporation’s Lanzhou Branch and Shenyang Aluminum-Magnesium Design and Research Institute, has been successfully developed. On March 21, 2008, an appraisal of the scientific and technological achievements was conducted by the China Nonferrous Metals Industry Association. The 16 SY400 electrolyzers installed at Chinalco’s Lanzhou branch are currently the world’s most advanced electrolyzers in terms of production current intensity, output per cell, and overall performance indicators; they also possess independent intellectual property rights. It features the following innovations: 1. An optimized and rational bus configuration has been designed, improving the stability of large-scale slot magnetohydrids ； 2. The use of a 5-segment flue structure design helps to improve gas collection efficiency and enhance the surrounding environment ； 3. Techniques such as a combination of ventilation for the electrolysis plant and overall thermal balance of the electrolyzers, integral welding of the cradle frame to the cell shell, welding of heat dissipation fins on the outside of the cell shell, welding of the cradle frame to the cell shell for the smaller surfaces of the electrolyzers, and placing both the cell shell and the lining entirely below the operating surface, were employed to ensure the thermal stability of large-scale electrolyzers and improve the working environment ； 4. The use of a technology in which the projections of the cathode carbon blocks correspond to those of the anode carbon blocks helps to ensure a uniform current distribution across the anode and cathode ； 5. A comprehensive control and standardized operation system for electrolyzers was adopted to effectively manage the thermal and material balances of these electrolyzers; baking startup techniques suitable for the stable and safe operation of large-scale electrolyzers were developed, resulting in production operation management techniques for 400kA electrolyzers ； 6. Four cathode carbon blocks of different qualities were used in the industrial tests for this project, and all of them met the test objectives for 400kA electrolyzers. In electrolyzers using 30% graphitic cathode carbon blocks, the anode current density also reached 0.82 A/cm2, and electrolyzers with graphitized cathode carbon blocks have further potential to increase the current intensity. The successful development of 400kA large-scale pre-baked anode electrolyzers has laid a solid foundation for China to compete internationally by providing electrolyzer technologies with greater capacity and more advanced technology.