Hydrogen Peroxide in ECF Bleaching Plant: Cenibra, 2001 Pulping Conference Proceedings

P. M. Henrique, M. M. Costa, F. M. Correia, M. J. O. Fonseca, J. R. C. Santos, A. B. Landim, C. L. Filho--With the purpose of expanding production of ECF bleached eucalyptus Kraft pulp, the company evaluated in laboratory and industrial test alternatives of hydrogen peroxide application in its ECF bleaching sequence - D0EoD1D2. The addition of hydrogen peroxide in this production line aims at the chlorine dioxide consumption optimization and to increase the production, maintaining 90 ± 0.5% ISO brightness. The following sequences were investigated: D0EopD1D2, D0EoD1P, D0EoD1(QP) and D0EopD1P. Industrial results confirmed the laboratory tests, showing that replacement rates varied from 1.1 to 2.4 kg ClO2/kg H2O2. More attractive replacement rates were obtained for the addition of 2.5 kg H2O2/adt in the last bleaching stage (D0EoD1P). However, a larger substitution of the total chlorine dioxide load was found necessary for the sequence D0EopD1P (5 kg H2O2/adt divided in both application points), which reduced 7.7 kg of ClO2/adt for kappa number 8.6. In addition, pulp and effluent characteristics are mentioned for each alternative, as well as corrosion rates of titanium under alkaline conditions (pH < 11),="" with="" low="" concentrations="" of="" hydrogen="" peroxide="">< 0.1%).="" results="" show="" that="" the="" addition="" of="" hydrogen="" peroxide="" in="" existent="" bleaching="" plants="" allows="" increasing="" the="" production="" with="" no="" modification="" in="" chlorine="" dioxide="" consumption="" at="" acceptable="" levels="" in="" operational="" costs="" and="" pulp="">