Modern industrial processes, while complex, can be made more efficient and robust with the right control strategies. Anssum’s project in South Africa, dubbed “Continuous Digester MPC”, exemplifies how advanced control methodologies can enhance production quality and reduce variability.

Project Overview

  • Category: Production
  • Location: South Africa
  • Project: Continuous Digester MPC
  • Status: Completed


The Kamir digester in FL#2 faced challenges with Kappa variability, a measure crucial for the quality of pulp production. Achieving consistent Kappa values is essential for ensuring the desired quality and reducing waste.

The Challenge

  • Reduce Kappa variability in the Kamir digester.
  • Minimise manual interventions by operators.
  • Explore potential improvements using advanced control strategies.

Anssum's Ingenious Solution

Anssum embarked on a mission to:

  • Develop a Model Predictive Control (MPC): This advanced control strategy uses a model of the process to predict future outcomes and adjust controls accordingly. Anssum’s team employed non-linear modelling and optimisation techniques to achieve the desired reduction in Kappa variability.
  • Focused Control Variable: Initially, only the top temperature of the digester was used as a control variable. This pinpointed approach ensured that the primary source of variability was addressed directly.
  • Expansion in Control Horison: Anssum also delved deeper by investigating the expansion in the EA set point, exploring the potential to further enhance control and reduce variability.

Stellar Outcomes

    • Significant Reduction in Operator Interventions: Post the implementation of the MPC, there was a 53% reduction in the time operators had to intervene with the controllers, signaling a more robust and stable process.
    • Dramatic Improvement in Kappa Variability: The project achieved a whopping 68% improvement in Kappa variability, ensuring consistent quality in production.
    • Enhanced Kappa Set-Point: The successful project enabled an increase in the Kappa set-point by 1.85 Kappa, pointing towards higher quality production.


The “Continuous Digester MPC” project stands as a hallmark of Anssum’s prowess in control engineering. By harnessing advanced control methodologies, Anssum transformed the production process of the Kamir digester, ensuring better quality, reduced waste, and higher efficiency.

In a world where quality and consistency are paramount, projects like these showcase how technical innovations can drive superior outcomes, setting new standards for industries worldwide.