Method for controlling the carbonisation process of aluminate lye

摘要

The method is used to control a process which proceeds continuously in a battery (1) of apparatuses (A, B, ..., M, N) connected in series. According to this method, the concentration of the caustic soda in the aluminate lye and in the liquid phase of the suspension at the outlet of each apparatus (A, B, ..., M, N) is measured periodically. On the basis of the measurements, the predictable values of the concentration of the caustic soda in the liquid phase of the suspension at the outlet of each apparatus (A, B, ..., M, N) are evaluated for points of time which precede the subsequent measurements. If, on doing so, the predicted value exceeds the set point by more than the amount of the maximum dynamic prediction error, the difference between the predicted value and the set point of the concentation of the caustic soda is eliminated by varying the mass flow of the aluminate lye in the sense of reducing it, and in all other cases by varying the mass flow of the gas into the apparatus.