The accurate online measurement of Kappa number, indicating residual lignin content, is essential for the optimization of cooking and bleaching in the production of eucalyptus kraft pulp. Valmet has development new and unique online method for the measurement of HexA, now available as an additional module working alongside the Kappa, brightness and fiber& shive properties measurements in the Valmet Kappa QC analyzer.
Summary
Challenge
Hexenuronic acid (HexA) in unbleached hardwood pulp increases the consumption of bleaching chemicals leading to higher production costs and product quality variability as well as worsening environmental performance.
HexA also consumes potassium permanganate in the Kappa number analysis which leads to an erroneous lignin content signal to automatic controls.
New and unique online method for the measurement of HexA, available as an additional module working alongside the Kappa, brightness and fiber & shive properties.
Can be used with a hot A (acidification) stage prior to bleaching or a hot A-stage combined with the D0-stage in a single hot D0-(Dhot) stage.
Results
First Hex-A measurement installation in South- America with excellent results.
New extremely interesting online measurement gives more information from lignin and Hex-A removal in eucalyptus pulping process.
Now we are opening new window to trending online Hex-A content from each process stage.
See how different eucalyptus grades demand different chemical treatment/process conditions.
First step is optimize A-stage operation to save bleaching chemicals, after that the next step is optimize cooking conditions to prevent extra Hex-A formation.
