Controllability of low-consistency chemical pulp refining process.

• Definition of the Degree of Pulp Refining Controllability (DOPRC) was proposed. • DOPRC values can vary from 0 to 100%. • Calculated Degree of Pulp Refining Controllability for tested pulp was equal to 8%. • Refining process is more controllable as the pulp development progresses. • Refining process should be constantly adjusted according to the current pulp development. Pulp refining process is considered as the most important unit operation in paper technology. Despite the simple principle of this process, it is a complex operation and not yet fully understood. It is difficult to control it thus the overall process has not been optimized so far. In the presented work, the low-consistency refining of softwood chemical pulp was investigated. The main objective of the presented research was to define a Degree of Pulp Refining Controllability (DOPRC) and to develop the method for calculation of this factor. Possible DOPRC values are between 0 and 100%. It was found that for the tested pulp, the overall DOPRC was equal to about 8%. Analysis of DOPRC changes with respect to the development of paper properties and paper web drainability suggests that the technological parameters of the process should be constantly adjusted according to the current level of refined pulp development. Image, graphical abstract [ABSTRACT FROM AUTHOR]