Optimization on the neutral sulfite semi-chemical (NSSC) pulping of birch
University of New Brunswick
Neutral sulfite semi-chemical (NSSC) pulping is the dominant industrial process to produce corrugated medium. In this thesis, the NSSC cooking process was investigated in a lab-scale setup, and the effect of cooking conditions and chemical charges were studied to understand their effect on different properties of the produced pulp. During the first phase, the cooking data were collected to create models that can predict the pulp yield, degree of sulfonation, and delignification degree, as well as determining the activation energy of the birch delignification process. In the second phase, cooked wood chips were refined into pulps and then made into hand sheets to evaluate the strength properties. The study also included how the Na2SO3 charge and refining would impact the paper strength, as well as identifying the threshold of the Na2SO3 charge, which can help in improving the paper strength while minimizing the chemical dosage.