In-Mill Improvements to Support ETF Replacement
Upcoming Improvement: Oxygen Delignification Process
Two-stage Oxygen Delignification technology will be incorporated into the pulp making process at Northern Pulp.
The system, which consists of oxygen reactors and wash presses, will be installed after the brown stock washing stage and before the existing bleaching stages. The system uses oxygen gas to react with residual lignin that remains in the pulp after brown stock washing. The lignin removed in this new stage will result in the use of less bleaching chemicals to whiten the pulp in the existing bleach plant. It is a significant and well-proven process for ECF pulp and as such it is often referred to as the first stage of bleaching (oxygen bleaching).
Yellow: Existing Equipment. Pink: Future oxygen delignification equipment which would be installed in the mill.
The environmental benefits of Oxygen Delignification:
Reduces Chlorine Dioxide bleaching chemicals by 30 – 40% - corresponding reduction in effluent organic loading for BOD, COD and AOX
Reduces effluent color
Reduces wood losses
Increases recovery of lignin to the liquor cycle – reduction in carbon footprint
Reduces energy consumption by reducing aeration requirements in the new ETF – reduction in carbon footprint
Reduces nutrient addition in the new ETF