T. Drengstig et al., ON THE ALF3 AND TEMPERATURE CONTROL OF AN ALUMINUM ELECTROLYSIS CELL, IEEE transactions on control systems technology, 6(2), 1998, pp. 157-171
In this paper we propose a control strategy for excess AIF(3) and bath
temperature of a prebake aluminum electrolysis cell based on analyzes
of measured data and studies of a simple dynamic model, Model validat
ion indicates that there are dynamics that the model does not capture,
and hence, we use real data of excess AIF(3) and bath temperature to
estimate AIF(3) and energy disturbances, respectively, The estimation
results show that the energy disturbance is the dominating disturbance
. Hence, the proposed control strategy is based on an almost constant
AIF(3) input close to average consumption and energy manipulations to
compensate for the disturbances, This requires the possibility for the
resistance reference to be reduced without decreasing the current eff
iciency, Compared to present control strategies, this introduces an ad
ditional degree of freedom in the controller, The proposed control str
ategy may imply a significant economic potential through increased and
stabilized current efficiency, reduced and stabilized energy consumpt
ion, reduced consumption of expensive additives, and prolongation of c
ell life.