Aluminium electrolytic cells: A computer simulator for training and supervision

A workstation-based simulator of an aluminium electrolytic cell has been constructed. A mathematical model of the cell is integrated with a database and a knowledge base, and the simulator serves as a tool for the training of personnel and for research related to cell dynamics and cell control. When used in conjunction with an expert system, it provides a powerful decision-making tool or an efficient supervisory system. The mathematical model, the simulator itself, the user environment, the interactive simulation procedure as well as examples of the use of the simulator are presented in detail.List of Symbols a _i parameters of electrolyte density calculation - AlF ₃ aluminium fluoride content w%] - Al ₂O₃ alumina content of electrolyte w%] - b _i parameters of electrolyte specific heat - c _i parameters of bath electrical resistivity - c _p ⁱ specific heat of electrolyte J/kg°C] - c _p ² specific heat of freeze J/kg°C] - c _p ³ specific heat of metal J/kg°C] - C alumina content of electrolyte w%] - C _s saturation concentration of alumina w%] - CaF ₂ calcium fluoride content of electrolyte w%] - CR cryolite ratio - H _F heat of fusion of electrolyte J/kg] - I line current kA] - k ₁ parameter of solution 1 1/s w%] - k ₂ parameter of solution 2 1/s w%] - k ₃ parameter of settling 1/s] - k ₄ parameter of alumina feeding kg/s] - k ₅ parameter of metal production kg/s kA] - k ₆ ratio of alumina-metal mass transformation - m ₁ mass of electrolyte kg] - m ₂ mass of freeze kg] - m ₃ mass of molten metal kg] - m _a rate of alumina addition kg/s] - m _m rate of metal production kg/s] - m _t rate of metal tapping kg/s] - Q total heat loss kW] - Q _A heat flow from electrolyte to anode kW] - Q _B heat flow from metal to cathode bottom kW] - Q _F heat flow from freezing zone to freeze kW] - Q _F1 heat flow from electrolyte to freezing zone kW] - Q _F2 heat flow from metal to freezing zone kW] - Q _Ha energy needed for alumina heatup kW] - Q _K heat flow from electrolyte to cathode kW] - Q _s heat flow from freeze to side-wall kW] - S ₁ solution rate of disperesed alumina kg/s] - S ₂ solution rate of settled alumina kg/s] - S ₃ settling rate kg/s] - T ₁ temperature of electrolyte °C] - T ₂ temperature of freeze °C] - T ₃ temperature of molten metal °C] - T _F temperature of freezing zone °C] - T _L cryolite liquidus temperature °C] - U total cell voltage V] - U _a voltage equivalent of enthalpy of metal production V] - x ₁ mass of dispersed alumina kg] - x ₂ mass of settled alumina kg] - x ₃ mass of dissolved alumina kg] - _i parameters of cryolite liquidus temperature - density of bath kg/m³] - electrical resistivity of bath m] - _c electrical conductivity of bath 1/m] - Note w% means percentage by weight