Automatic determination of optimal endpoint of 1st carbonatation – factory trials

The objective of this paper is to determine the applicability of automatic control of the optimal point in 1st carbonatation of juice purification in a beet sugar factory. To realize the automated determination, a pilot carbonatation tank was constructed and installed in the bypass of the industrial production. Automatic stepwise carbonatation was applied to the circulation juice of the 1st carbonatation. pH value measurement started at a pH value of the circulation juice of approximately 12, and carbonatation gas was injected until the pH reached 10.7 in 0.1–0.2 pH units per step by means of an automatic control system. After every pH step, juice was left to settle for 4min. At the end of this clarification time, turbidity measurement was done. In total carbonatation, sedimentation and turbidity measurement take approximately 45–50min. When the period was completed, the tank was discharged and automatically washed out by extraction feed water. Data obtained at the end of the period were recorded and displayed on a personal computer. The computer software prepared for this system compares all the turbidity values, chooses the lowest one and designates the corresponding pH value at that turbidity as the optimal pH.