Kappa QC controls stabilize pulp bleaching in Kaukopää
Nov 17, 2015
Imatra Mills consist of two production units: Kaukopää and Tainionkoski, 250km east of Helsinki, on the southern shore of Lake Saimaa. Together, they employ approximately 1,000 people and produce one million tonnes of board and paper annually. In the latest advance at the Kaukopää mill, Valmet has introduced its latest concept in the form of stabilizing controls for the entire bleach line.
As a pilot project, I think it went rather well. Valmet’s training in the use of the control, principles and tuning parameters was quite good. It is a very open system, complex but easier to understand.”
Marko Harinen, Specialist at Stora Enso’s Pulp Competence Centre
Summary
Location
Stora Enso Kaukopää mill
Customer challenge
One of the objectives for the new embedded control concept was to remove the ‘black box’ reputation of bleaching controls and make fiber line stabilization easier to understand and implement for pulp mill staff
Solution
The controls, now embedded in the Kappa QC analyzer, provide external setpoints to the chemical dosage controllers using easily understood function blocks to perform filtering and calculations. The basic controller uses a Kappa factor control modified with predictive feedback taking Kappa/brightness and COD (Chemical Oxygen Demand) into account. Measurement data from the analyzer plus inline sensors are combined with settings given by the operator to carry out the various calculations required for each of the process stages and provide setpoints for the chemical controllers.
Results
The basis for better upper level controls and reduction in final brightness variation meeting expectations.
