Hydrogen Peroxide Reinforced Extraction Lowers Chlorinated Organics and Color in Bleach Plant Effluent, 1990 Pulping Conference Proceedings

The capability of hydrogen peroxide and oxygen in the E1 stage to produce pulps of low kappa factors while maintaining good pulp quality was examined in laboratory studies and mill trials. Laboratory studies showed that a reinforced extraction stage (EOP) could produce equivalent brightness and higher viscosity at 0.17 Kappa factor as compared to E-stage pulps at 0.22 Kappa factor. Mill trials resulted in as much as a 28% decrease in total available chlorine requirements. The use of an (EOP)-stage and a 0.15 Kappa factor in laboratory work showed that the extraction stage effluent color could be decreased by 78%. Similarly, the chlorinated organics from the combined chlorination and extraction stages are decreased by 42%. Mill trial results showed that color and AOX were decreased by 50 and 42%, respectively.

The cost of decreasing the Kappa factor with hydrogen peroxide and oxygen is partially off set by lower chlorine and caustic costs. Compared to the alternative bleaching process with high substitution, Cl02 the cost of EOP bleaching is less than $1/BDT more. EOP bleaching costs would be significantly lower than high substitution if major capital costs are included for expanding chlorine dioxide generating capacity.