CONTINUOUS DIGESTER MPC

A LEAP IN PRODUCTION EFFICIENCY

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

Background

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.

Conclusion

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.“

STREAMLINING PRODUCTION

BATCH DIGESTER SCHEDULING IN SOUTH AFRICA

In the realm of production, efficient scheduling can be a game-changer, optimising resources and maximising output. Anssum’s ongoing project in South Africa, centered on Batch Digester Scheduling, is paving the way for enhanced operational efficiency.

Project Overview

  • Category: Production
  • Location: South Africa
  • Project: Batch Digester Scheduling
  • Status: In progress

Background

Batch digesters are at the heart of numerous production processes, requiring intricate scheduling to ensure seamless operations. An optimal cook sequence not only maximises production output but also minimises resource wastage.

The Challenge

Efficiently scheduling cooks between digesters.

  • Identifying and rectifying out-of-phase digesters, which can hamper the overall efficiency of the production process.

Anssum's Innovative Solution

To address these challenges, Anssum embarked on the development of a state-of-the-art scheduling tool specifically for the MgO#1 digester plant:

  • Efficient Cook Sequence Selection: The tool aids operators in determining the most efficient sequence of cooks between digesters. By streamlining this process, the tool ensures that each digester is utilised to its maximum potential.
  • Identification of Out-of-Phase Digesters: An out-of-phase digester can disrupt the flow of operations. The scheduling tool is adept at pinpointing such digesters, enabling operators to take timely corrective actions.

Benefits & Outcomes

While the project is still in progress, the scheduling tool promises a host of benefits:

  • Enhanced Operational Efficiency: By optimising the cook sequence, the tool aims to boost the overall efficiency of the digester plant.
  • Resource Optimisation: Efficient scheduling minimises resource wastage, leading to cost savings.
  • Timely Problem Identification: With the ability to identify out-of-phase digesters, the tool ensures that potential disruptions are addressed promptly.

Conclusion

The Batch Digester Scheduling initiative in South Africa is a testament to Anssum’s dedication to enhancing production processes through innovative solutions. As the project progresses, it is set to redefine operational efficiency standards in the industry.

“Anssum continues its journey of innovation, merging technology with industry expertise to set new benchmarks in production excellence.“

PIONEERING PRODUCTION ENHANCEMENT

BATCH DIGESTER MODELLING IN SOUTH AFRICA

In the dynamic world of production, accurate prediction and control are paramount. Anssum’s recent project in South Africa, focusing on Batch Digester Modelling, exemplifies a groundbreaking approach to enhancing production efficiency and accuracy.

Project Overview

  • Category: Production
  • Location: South Africa
  • Project: Batch Digester Modelling
  • Status: Monitoring accuracy

Background

Batch digesters play a crucial role in processing raw materials. However, the inherent challenge lies in ensuring that each cook achieves the desired viscosity. A deviation from the targeted viscosity can result in an overcook or undercook, leading to wastage and inefficiencies.

The Challenge

Achieving consistent viscosity for each cook in batch digesters.

  • Minimising the occurrence of overcooks and undercooks, which can compromise product quality and lead to resource wastage.

Anssum's Ingenious Solution

To address the challenge head-on, Anssum employed advanced modelling techniques:

  • State Space Model: This mathematical model describes the dynamic behavior of the system and provides insights into how changes in inputs affect the system’s outputs.
  • Integration of Kalman Filter: A renowned algorithm, the Kalman filter estimates the variables of interest from indirect and noisy measurements. In this context, it was employed to predict the viscosity of each cook with high accuracy.
  • Viscosity Prediction for Process Adjustment: The viscosity prediction derived from the model and filter was then utilised to fine-tune the S-factor. By adjusting this factor, Anssum aimed to achieve optimal viscosity and significantly reduce the chances of overcooks and undercooks.

The Way Forward

Currently, the focus remains on monitoring the accuracy of the model and its predictions. This ongoing assessment will ensure that the model remains robust and continues to deliver optimal results, driving efficiency in batch digester operations.

Conclusion

The Batch Digester Modelling project in South Africa underscores Anssum’s commitment to leveraging cutting-edge technologies and methodologies to enhance production processes. By integrating state-of-the-art modelling techniques and predictive algorithms, Anssum is poised to redefine the standards of production efficiency and accuracy in the industry.

“Anssum’s drive to innovate and optimise sets a benchmark for the future of production, demonstrating a blend of technological prowess and industry expertise.“

BLOWTANK CONSISTENCY CONTROL OPTIMISATION

SPEARHEADING SUSTAINABLE PRODUCTION IN SOUTH AFRICA

In the realm of water conservation, energy efficiency, and optimised production, the right control mechanisms are paramount. Anssum, with its unwavering commitment to these pillars, embarked on a project in South Africa to optimise the consistency control of blowtanks, paving the way for a more efficient and environmentally-friendly production process.

Project Overview

  • Focus Areas: Water, Production, Energy
  • Country: South Africa
  • Description: Blowtank Consistency Control Optimisation
  • Status: Completed
  • Timeline: September 14, 2022 – October 30, 2022

The Challenge

Consistency control within the blowtank discharge process was identified as an area ripe for enhancement. Achieving optimal pulp consistency is crucial for effective brown stock washing. However, the existing system required frequent manual intervention, leading to inefficiencies and increased operational complexities.

The Initiative

Anssum proposed a revamped control structure for the blowtank discharge process. The new design incorporated:

  • Feedforward Control: Anticipating future changes by using current measurements.
  • Feedback Control: Adjusting the process based on the difference between the desired and measured values.
  • Cascade Control: Using multiple controllers to manage a single control loop, enhancing the accuracy.
  • PID Logic Infrastructure: This infrastructure is straightforward to implement and offers a balance of proportional, integral, and derivative actions, ensuring smooth and precise control.

The goal was to regulate pulp consistency using only two control valves supplying hot liquor as manipulated variables, the pulp discharge valve positions as disturbance variables, and the blow effluent pulp consistency as the controlled variable.

Outcome and Challenges

The results were compelling. The Mean Absolute Error (MAE) of consistency was reduced by a notable 17%. Furthermore, the need for manual intervention to control blowtank consistency was eliminated, streamlining the process and ensuring consistent, high-quality output.

Concluding Thoughts

The Blowtank Consistency Control Optimisation project exemplifies Anssum’s dedication to sustainable and efficient solutions. By integrating advanced control mechanisms into the production process, Anssum has not only enhanced the quality of the output but has also underscored the importance of automation and precision in modern industrial operations.

“As industries face increasing pressures to conserve resources and enhance production efficiency, initiatives like this one by Anssum provide a roadmap for sustainable and optimised operations in the future.“