Practical Experience with Kamyr Digester Level Self-Tuning Control

This paper presents the application in a mill of a chip level self-tuning regulator (STR). Three strategies using the same STR algorithm are compared, one using the blow flow, the others using the outlet device speed as main manipulated variable. The four strategies are shown to behave similarly in terms of control performance. However, for operational reasons, the strategies using the out-let device speed are preferred by the mill personnel. The level control scheme has been well received by the operators and is now in continuous operation.