Millwide Optimization for Pulp Mills

The ultimate goal of any overall optimization is to reach target values for key product properties with the lowest possible production cost by:

• Mill-wide production rate and Inventory management: Production is measured as accurately as possible from multiple points, starting from exact dry wood mass flow to the digester. This will enable more accurate control of processes and prevent production upsets caused by inaccurate measurements.

• Quality controls and Cost optimization: When unit processes are optimized, we can utilize process tests and analytical tools to determine the optimal production targets for the entire mill. It also needs to consider raw materials, requirements for different grades, production limitations, energy and chemical costs. With this iterative search, the overall strategy will be tailored to the mill's specific needs.

This application also incorporates:

• The operator is focusing on higher-level activities now

• Metris intuitive views with production, costs and quality KPIs to inform the operator of key mil targets
• Automation and Asset Reliability information are summarized for direct interface with maintenance teams by operators
• Dashboards informing the operators about opportunities to improve process performance
• Mobile applications to visualize information from and on the field
• High-level plant operation dashboard
• Immediate identification of area-by-area constraints & operating modes

Examples of mill-optimized plants:

• The Woodyard and digester are optimized so that they will maximize the yield, considering cost and process constraints on the downstream processes.
• This will also give alkali and steam savings from the digester and typically maximizes the strength properties of the pulp.
• The washing area optimizes the trade-off between bleaching chemicals and makeup costs and, on the other hand, energy usage on the recovery line.
• In Bleaching and Oxygen delignification, the optimal delignification and brightness profile is selected to minimize chemical costs and balance that to give the desired final properties for the product.
• Stock preparation and paper machines are focused on minimizing the cost that comes from refining energy, furnish blend cost and basis weight.
• In chemical recovery, each unit process is optimized to minimize the cost and stabilize the white liquor strength and steam pressure.

Benefits:

• Overall quality control: Optimize pulp properties for the final product

• Reduction of operating costs

• Increase in Mill-wide production rate

• Inventory management