OPT800 Wash

ABB AbilityTM Advanced Process Control for better managing of brown stock washing lines

OPT800 Wash automatically maintains stable brown stock washing conditions and filtrate tank levels to help improve washing process efficiency, increase production and decrease environmental impact. The Advanced Process Control solution stabilizes the process and performance of brown stock washers, optimizing water, chemical and steam consumption.

Since washing is a sequential, countercurrent operation, it takes only a few minutes to destabilize the process and then recovery can take several hours. Poor performance of the brown stock washers can significantly affect the broader stability of the pulp mill operations and result in increased operating costs due to both higher energy demand in the evaporators and higher bleaching chemical consumption.

OPT800 Wash helps solve all these issues by computing the optimal dilution factor values and defoamer charge using pulp conductivity measurements, while also considering the limits on the filtrate tank levels. Optimal dilution factors lead to important reductions in alkali/soda losses, black liquor solids (BLS) and freshwater consumption.

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  • Conductivity, dilution factor and defoamer control
  • Filtrate tank farm control
  • Pulp tracking and pulp quality footprint programs
  • Real-time adaptive modelling: Automatic adjustments based on process changes
  • Higher-order model support: Captures process dynamics accurately
  • Cost optimizer: Looks for ways to optimize operational costs within process constraints
  • KPI Dashboard and control usage reports by day/shift
  • Performance monitoring, with both on-site and remote access for customers and ABB
  • Task oriented and user friendly customizable operator displays


  • Better washing efficiency
  • Better filtrate tank level control
  • Increased capacity by 1-4%
  • Lower soda/alkali losses
  • Reduced wash water consumption by 1-5%
  • Decreased chemical loading in bleaching
  • Reduced steam consumption in evaporation by 2-10%

How it works – Tightly managing tank levels and conductivities

ABB’s OPT800 Wash is an advanced process control (APC) solution that expertly monitors and controls the brown stock washing process on the fiber line. The conductivities at each washing stage are tightly controlled to minimize alkali losses below the allowable high limit.

The APC maintains the filtrate or seal tank levels within the specified critical limits. Any deviation of the tank level outside the critical limits will affect the washing rate and efficiency.  Control performance will not degrade over time with always-on monitoring and analysis of the APC solution.

Highly-intuitive, task-oriented and easy-to-access operator displays are provided to monitor real-time, historical and prediction trends data as well as modify tuning parameters. OPT800 Wash allows customization of the user interface to meet a wide range of project needs. The reports module calculates the key performance indicators such as chemical usage controls utilization, and steam consumption, and presents them in the day/shift report. OPT800 Wash consists of the state-of-the-art APC software application including installation, start-up, tuning and training service.

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