Extended Oxygen Delignification with the Oxy TracTM Process

Effect of Hydroxyl Radical on the Selectivity of Delignification during Oxygen Delignification of Bamboo Pulp

The main challenge in the oxygen delignification process is the improvement of selectivity. To further understand the effect of the amount of hydroxyl radicals on the selectivity of oxygen delignification, in this work, the hydroxyl radicals were generated by the improved Fenton reaction system and were quantified by UV spectrophotometry. Antioxidants such as ascorbic acid were applied for the ...

Carbohydrates in Oxygen Delignification. Part I: Changes in Cellulose Crystallinity

INTRODUCTION There has been a steady increase in the use of oxygen delignification worldwide since the first commercial installation in South Africa in 1970 [1]. The degree of delignification achieved in the oxygen stage is ultimately limited by pulp strength considerations, and averages 40% delignification industrially [2,3]. With greater degrees of delignification, the oxygen delignification ...

Nitrogen-Centered Activators of Peroxide-Reinforced Oxygen Delignification

In an effort to augment the efficiency of an oxygen delignification stage, we examined the effectiveness of various heterocyclic aromatic nitrogen compounds as possible activators of such a stage. It was shown that a variety of such compounds may act as activators in the presence of hydrogen peroxide, improving the delignification efficiency of oxygen delignification. Among the group of activat...

A new CSTR for oxygen delignification mechanism and kinetics study

Influence of Nonprocess Elements on Lignin Structure During Oxygen Delignification

A series of kraft pulps were prepared in which the level of calcium was selectively enriched and depleted. These pulps were then oxygen delignified, and the pulps were characterized according to kappa number and viscosity. The residual lignin samples were isolated via acid-hydrolysis and characterized by NMR techniques. The results indicated that the presence of nonprocess elements could impact...