Oxygen Delignification

Intensive delignification with pure oxygen.

Delignification with oxygen reduces active chlorine requirements, environmental impact and water treatment operational costs.

Oxygen delignification enhances yield in bleached pulp production and offers relevant operating cost advantages over the use of bleaching agents. Not less important is the environmental benefits it leads to, mainly the minimisation of adsorbable organic halides (AOX). Also, oxygen application leads to lower wastewater treatment oxygen requirements and less color in effluent.

How oxygen delignification
works

The process of lignin removal uses
oxygen to reduce active chlorine
requirements in the bleaching plant.
This process is an important step
towards total chlorine free (TCF) and
elemental chlorine free (ECF) in pulp
production.

Lower cost
Lower overall bleaching
chemical costs
Less
environmental
impact
Reduced or eliminated AOX
production reducing
environmental impact
Lower BOD/COD
Lower BOD/COD production
and less colour in the
effluent
Reduced
wastewater
Reduced wastewater
treatment costs (COD and
colour removal)
Better yield
Better yield than extended
cooking
Important
bleaching
Important bleaching step
towards TCF or ECF pulp
production and mill closure

Oxygen in delignification

We can find different types of delignification processes:

  • HCOD – High Consistency Oxygen Delignification
  • MCOD
  • Medium Consistency Oxygen Delignification
    (following bullets within MCOD)
  • Double Stage
  • Single Stage
  • Mini
  • Pre – bleaching cellulose HCOD and MCOD applications are well stablished technologies, adapted to the concept of a modern plant
oxigen operator image

Do you stillhave questions?

At Nippon Gases we are called “The GasProfessionals” for a reason, and it’s because we’ll be able to solve any doubt.

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