Research On Heat Exchange System Of New Aluminum Reduction Cell

Now, the electric energy consumption of primary aluminum has been reduced to 13000-14000 kW·h/t-Al, but the energy efficiency is not more than 50% or so. More energy saving research works have been done to reduce the energy consumption of aluminium electrolysis by decreasing average voltage and increasing current efficiency. By the analysis on the energy balance, half of the electric energy for aluminium electrolysis is sporadic to environment in the form of heat energy. And the heat dissipated from the top of the cell accounts for 48%,43% from side and 9% from the bottom. In order to save energy, electrolytic cell sidewall waste heat recovery and its affecting factors were studied in this paper.'Firstly, theoretical energy balance, heat dissipation distribution and heat dissipation mode were analyzed. The structure of a new kind of waste heat recovery aluminum reduction cell was comprehensive designed, and the heat transfer medium which suitable for this experiment was chose.Then the effect of input power and flow rate of molten salt on the recovery power and recovery efficiency were studied, when coke as the heating element in the electrolytic cell baking. Under a condition of stable input power, the recovery power and recovery efficiency corresponding increase or decrease when flow rate of molten salt is increased or decreased. Under a condition of stable flow rate of molten salt, recovery power increase or decrease when input power is increased or decreased, but recovery efficiency is complete opposite, recovery efficiency decrease or increase when input power is increased or decreased.Finally, the effects of flow rate on the recovery power and recovery efficiency were studied. During the course of electrolysis at a temperature of 900℃, the current efficiency was 90%, electric current fluctuated in an interval of 1865-2056 ampere, and voltage fluctuated from 11.53V to 12.36V. Under the stable electrolytic process, the recovery power and recovery efficiency corresponding increases with the increasing of molten salt flow rate. The recovery power of 9890W and recovery efficiency of 41.9% were obtained under the molten salt flow rate of 135.5 cm3/s. It complete reaches the result of energy saving.