(186h) Numerical Analysis of Effect of Diaphragm Structure Based on Thermo-Electro-Magneto-Hydrodynamics Coupling Model in Magnesium Electrolysis cell

Authors: 
Liu, C. L. - Presenter, East China University of Science and Technology
Jiang, Y. F., East China University of Science and Technology
Xue, J., East China University of Science and Technology
Yu, J. G., East China University of Science and Technology
Magnesium production is one of the most energy-intensive industrial processes. Like the Hall-Herault process of aluminum production, The core reactor is the electrolysis cell and its electrolysis efficiency is a crucial factor that profoundly affects the amount of energy consumed. Thus the energy consumption and current efficiency are crucially important indexes.

In the newly designed electrolysis process, magnesium oxide is dissolved in a rare earth chloride-containing electrolyte and electrolyzed to produce magnesium and oxygen gas similar to the production of aluminum [1] and lithium [2] in electrolytic cells. Considerable research efforts are reported on the use of commercial software to simulate flow field[3,4], thermoelectric field [5–7] and magnetohydrodynamic models [8] in magnesium electrolysis cells.

To improve the circulation of the electrolyte, a baffle plate were set between the electrolysis department and collect department. The ratio of the quantity of magnesium droplets in the metal separating compartment during the primary circulation to the whole quantity of magnesium droplets generated at the cathode is defined as the primary separation rate of magnesium droplets (PSR)[10]. In order to improve the electrolysis efficiency, the cell needs to increase its primary separation rate of magnesium droplets.

This work concerns the optimization of the electrolysis cell based on a three-dimensional thermo-electro-magneto-hydrodynamics coupling model. The flow field of mathematical model was validated by the cold model experiments of PIV in the previous research[9]. The structure of the diaphragm and buffle plate were studied to improve the PSR. The PSR could increase from 18% to 40% after optimizing the structure and position of the diaphragm and buffle plate.

  1. Tessier J, Duchesne C, Tarcy GP, Gauthier C, Dufour G. 2012 Multivariate Analysis and Monitoring of the Performance of Aluminum Reduction Cells. Ind. Eng. Chem. Res. 51, 1311–1323. (doi:10.1021/ie201258b)
  2. Oliaii E, Désilets M, Lantagne G. 2017 Numerical analysis of the effect of structural and operational parameters on electric and concentration fields of a lithium electrolysis cell. J. Appl. Electrochem. , 1–16. (doi:10.1007/s10800-017-1073-2)
  3. Liu C-L, Sun Z, Lu G-M, Song X-F, Yu J-G. 2015 Experimental and numerical investigation of two-phase flow patterns in magnesium electrolysis cell with non-uniform current density distribution. Can. J. Chem. Eng. 93, 565–579. (doi:10.1002/cjce.22135)
  4. Sun Z, Zhang H, Li P, Li B, Lu G, Yu J. 2009 Modeling and simulation of the flow field in the electrolysis of magnesium. JOM 61, 29–33. (doi:10.1007/s11837-009-0066-y)
  5. Sun Z, Liu C, Lu G, Song X, Sun S, Sun Y, Yu J. 2011 Coupled thermoelectric model and effects of current fluctuation on thermal balance in magnesium electrolysis cell. Energy and Fuels 25, 2655–2663. (doi:10.1021/ef2004333)
  6. Sun Z, Cai L, Liu C, Lu G, Yu J. 2017 Analysis for effects of electrolyte level on energy consumption in magnesium electrolysis by finite element method. Can. J. Chem. Eng. 95, 648–655. (doi:10.1002/cjce.22708)
  7. Sun Z, Cai L, Ni H, Lu G-M, Yu J-G. 2018 Coupled electro-thermal field in a high current electrolysis cell or liquid metal batteries. R. Soc. Open Sci. 5, 171–179. (doi:10.1098/rsos.171309)
  8. Sun Z, Li P, Lu GM, Li B, Wang J, Yu JG. 2010 Effect of Electromagnetic Field on Three-Phase Flow Behavior. Ind. Eng. Chem. Res. 49, 10798–10803. (doi:Doi 10.1021/Ie100513w)
  9. Liu C, Sun Z, Lu G, Song X, Yu J. 2015 3D and 2D experimental views on the flow field of gas-evolving electrode cold model for electrolysis magnesium. Flow Meas. Instrum. 45, 415–420. (doi:10.1016/j.flowmeasinst.2015.07.011)
  10. Liu C, Zhao Q-W, Sun Z, Lu G, Yu J. 2018 Analysis of Magnesium Droplets Characteristics and Separation Performance in a Magnesium Electrolysis Cell Based on Multiphysical Modeling. Arab. J. Sci. Eng. (doi:10.1007/s13369-018-3148-8)