Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for determining and applying a distribution of oxidizing agents in delignification of a pulp bleaching cycle. The method obtains an incoming kappa value of an unbleached pulp slurry and a target kappa value expected for a bleached pulp slurry. A model generates a sequence kappa factor based on these values, and a total equivalent chlorine (TEC) factor from the sequence kappa factor and the incoming kappa value. Scenarios are simulated using the TEC factor, each scenario specifying a unique distribution of dosage targets for oxidizing agents and having a total consumption score for the oxidizing agents that is determined based on the dosage targets for the oxidizing agents. A scenario with the lowest total consumption score is selected, and the model applies the dosage targets of oxidizing agents for the selected scenario during the pulp bleaching cycle.

Abstract: Thermomechanical pulp is an important process for producing fibrous mass used in papermaking. A two-level control strategy that stabilizes and optimizes the refining process has been developed. The Stabilization layer consists of a multivariable model predicative range controller that regulates the refiner line operations. The Quality Optimization layer provides the pulp quality control as measured by an online pulp quality (freeness, fibre length) sensor. This control startegy leverages the natural decoupling in the process. The modular design technique is able to handle multiple refiner lines that empty into a common latency chest. A global optimizer is also used to integrate and coordinate the two layers for enhanced constraint handling.