Oxygen delignification and effects on pulp properties

Kraft pulping and oxygen delignification are important unit processes in production of pulp and paper. Oxygen delignification has the potential to modify fiber properties, resulting in improved product properties. Due to the oxidation of lignin and some carbohydrates, it is possible to increase the amount of charges present in the fibers. Higher charges lead to an increase in swelling and, consequently, to a better fiber conformation and bonding. A pulp entering the oxygen stage with higher kappa number from the cooking process, will decrease the cooking energy and the higher amount of charges reduces the refining energy needed to achieve the same or even higher mechanical strength.

PhD student Cláudia Esteves