Debarking: Why debarking ?
• Low yield: The fibre proportion of bark is very low
• Damage to equipment: Hard granules of sand can be embedded in the bark
and cause wear in chipping equipment.
• High content of extractives: The high content of extractives in bark gives
higher consumption of cooking and bleaching chemicals. They give rise to pitch
problems in both pulp and paper mill.
• Drainage obstacle: The small bark cells may also cause problems in dewatering
the paper web formed on the paper machine
• Dirt on paper: Some of the bark cells are not degraded in neither cooking nor
bleaching and end up as dark spots on the paper web.