77.5% Less Emissions-Related Downtime. 4.5% Higher Throughput. ROI < 6 Weeks.
77.5% Less Emissions-Related Downtime. 4.5% Higher Throughput. ROI < 6 Weeks.
Fast. No new hardware. No new instrumentation.
The recovery boiler had become a bottleneck on the wider operation. Instability on the boiler was contributing to emissions-related downtime, steam temperature variation, turbine disruptions, and lost production opportunity.
Anssum upgraded recovery boiler operation using the existing control system, with no additional hardware or instrumentation.The result was a 77.5% reduction in downtime due to high emissions, elimination of turbine trips, stabilised steam temperature, a 4.5% increase in throughput, and an estimated annual business value of greater than USD 2 million.
800ktpa Kraft Pulp Mill in the Southern Hemisphere
The recovery boiler is a critical part of the wider operation, and its performance had a direct effect on production availability, reliability risk, and energy cost across the mill.
Recovery Boiler Emissions and Instability Limit Mill Throughput
Low recovery boiler control maturity limits performance across the wider mill. Emissions-related downtime regularly forced production cuts, while unstable steam temperatures and combustion performance increased energy costs and placed additional strain on the turbine.
The main challenges included:
- Emissions-related production cuts affecting approximately 16% of available operating time.
- Unstable steam temperatures and inefficient combustion.
- Turbine trips and unplanned downtime.
- Frequent manual intervention by operators.
- Lost production capacity and higher energy costs.
Sustainable Process Improvement Without Capital Investment
Anssum focused on improving how the recovery boiler was controlled and operated with existing equipment, infrastructure and instrumentation.
An advanced control and optimisation solution was implemented within the existing DCS. The solution was developed in close collaboration with engineers, DCS specialists and operators to ensure that it addressed the actual operating constraints while remaining practical for day-to-day use.
This allowed the mill to improve stability, reduce emissions-related losses and increase throughput without a capital-intensive upgrade.
Implementation Process
Anssum implemented an advanced control and optimisation upgrade on the recovery boiler using the existing control system and successfully delivered the product: Sustainable Process Improvement. The upgrade was embedded entirely within systems and environments already familiar to the plant. This avoids introducing additional hardware, instrumentation, or new operating environments.
By working within the existing control system, the approach reduced implementation friction, enabled a faster handover, and supported strong internal ownership. The aim was not only to improve performance, but to do so in a way the plant could sustain without dependence on external support.
Perhaps the most critical part of the work is collaboration across engineering, DCS specialists, and operations. Operator input helps shape both the design and implementation of the solution. Care is taken to ensure operators understand the upgrade, how it affects the process, and how to operate effectively under the improved conditions. This supports confident day-to-day operation and strong internal ownership after go-live.
Estimated Annual Business Value Greater Than USD 2 Million
Production availability improved significantly
Production downtime due to high emissions reduced from 16% to 4%, effectively removing emissions as a constraint on production. This enabled the mill to operate closer to full capacity.
Throughput increased
Recovery boiler throughput increased by 4.5%, confirming that the boiler was no longer the limiting factor in the process and unlocking additional production capacity across the mill.
Stability improved
Turbine trips were eliminated, and unplanned turbine downtime reduced by nearly 90%. This reflected a step-change in steam quality and system stability, reducing both direct losses and operational risk.
Energy efficiency improved
Improved boiler performance increased steam generation, reducing reliance on coal by approximately 25 t/day. This reduced fuel cost while also lowering emissions.
Reduced external power dependency
Increased turbine output reduced electricity purchases from the grid by approximately 1 MW, contributing further to cost savings and energy self-sufficiency.
Financial summary
Estimated annual business value greater than USD 2 million. ROI in less than 6 weeks.
Key Takeaways
Bottlenecks Hide Significant Value
Removing a single process constraint can unlock benefits across production, energy use and reliability.
Better Control Beats Capital Spend
Major performance gains were achieved using the existing control system, without new hardware or instrumentation.
Stability Creates Capacity
More stable boiler operation reduced downtime and allowed the mill to operate closer to its true production potential.
Energy and Production Improvements Go Hand in Hand
Improved boiler performance increased steam generation while reducing external energy requirements.
Fast Results Matter
The improvements delivered an estimated annual value greater than USD 2 million, with an ROI of less than six weeks.
