The implementation of APC resulted in significant savings and is highly effective in optimising the lime kiln. instrumentation, on-line analysers, regulatory control logics (PID), and supervisory control logic. APC would further optimise the existing control system by coordinating their functioning by calculating optimal setpoints. APPLICATION OF ADVANCED PROCESS CONTROL FOR LIME KILN OPERATIONS Advanced Process Control application suite was implemented at a multi-fuel lime kiln in Europe. The aim was to control the cold end temperature at setpoint and the hot end temperature and oxygen within specified limits by manipulating the total fuel flow and the draft fan speed. The changes in production were accounted for by modeling the effect of the lime mud feed in the control system. The first step towards implementing a robust APC solution is modeling the process (as seen in Figure 4). Step tests were performed to develop data-based accurate process models. The implementation of APC resulted in significant savings and is highly effective in optimising the lime kiln, reducing downtime, and improving lime quality. There was a significant reduction in the cold end temperature (58%) and oxygen (26%) variations. The reduction in these variations improved the lime kiln stability and overall efficiency, enabling the mill to reduce energy consumption by 5%. The improvement was achieved through optimal manipulation of the ID fan speed and fuel flow, which were previously controlled manually by operators. Further, the stable process also resulted in an improved lime quality, which helped achieved lower to improve operations, lower service costs and reduce downtime. Problems that once required experts to travel to the site can often be resolved remotely via collaboration operation centers. Condition monitoring, machine learning, and data analytics enable a small team of ABB experts to monitor and optimise a large installed base of equipment effectively. Collaborative Operations is a way of operating that allows both supplier and papermaker personnel to operate on the same information and levels of residual carbonate due to reduced variability. BENEFITING FROM COLLABORATIVE OPERATIONS Another feature of the installation was the utilisation of ABB Ability™ Collaborative Operations. Utilising IOT infrastructure, Collaborative Operations provides a new breed of connected services that leverage the vast amount of information available today. Advanced data processing and analytical applications uncover trends, data patterns and relationships Figure 4. Plant step tests were performed to identify data-driven process models. WORLD PULP&PAPER 93