Metso’s Bleaching Optimization selected by Burgo Ardennes mill in Belgium has smoothed out bleach plant operation and demonstrated an 8.7% savings in bleaching chemicals with improved brightness stability. A continuous improvement program extends the gains for the mill.
Following a detailed process control audit by Metso, improvements have been achieved by a successful implementation of advanced controls based on new Metso Kappa Q and Metso Cormec 5 analyzers. The mill produces 400,000 t/y of mixed hardwood bleached kraft pulp, which presented a particular control challenge. Metso’s team effectively implemented the control based on in-depth knowledge of the process and how to deal with disturbances.
Ever since the project was completed in summer 2013, stability has been maintained and augmented by a continuing Performance Service Agreement (PSA). After initial commissioning, the controls have been adapted to significantly higher production rates in the latter part of 2013. The service includes process monitoring though a link to Metso and 24/7 telephone help services. Daily and monthly remote diagnostic reporting by Metso outlined specific process improvements that were implemented with positive results. Improvements in chemical utilization are continuing.
Eric Bazzoni, Fiber Line Production Manager, sums up the mill’s objectives and results achieved: “Our goal with the new measurements and controls was to stabilize the process and reduce costs. Now, we have a big advantage because we can achieve the right brightness even at higher production rates. Before, it was difficult to achieve stability from shift to shift, as operators would manually change parameters. Now, the control system adjusts by itself, and the parameters are the same. We do not have any off-specification pulp.”
He points out that chemical consumption is kept to a minimum since the chemical residual of chlorine dioxide after the bleaching towers is at a very low level. Additionally, there are no problems with off-gassing that might cause health, safety and environmental problems.
Pierre Carnevali, Mill Projects Project Manager, adds his thoughts on the controls implementation: “I am impressed that the Metso engineers have adapted the controls to our own process, giving us a tailor-made control solution for our mill.”
Regarding continuing process performance services, Bazzoni finds this a useful tool, as it gives a concise report on key control objectives and uncovers any problems. Carnevali adds, “The reports tell us if we are in a good control range or not, and if we are consuming the right amount of chemicals.”
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