Optimization of Hydrogen Peroxide Stage in TCF Bleaching Sequences of Hardwood Kraft Pulps, 1996 Pulping Conference Proceedings
J. Pedrola.
T. Vidal
J.F.Colom
Universitad Politecnica de Cataiunya.
An OXZP bleaching sequence ended by a hydrogen peroxide stage has proved to be a good choice in order to control both viscosity and brightness of the bleached pulp. The P stage has been optimized applying a four variable-statistical sequential plan. The variables and applied ranges are: hydrogenperoxide charge (0.5-2.5 % o.d.p.), time (1-3 h), temperature (70-90 °c) and NaOH charge (0.2-2.2 % o.d.p.). The influence of these variables on brightness, viscosity and amount of consumed hydrogen peroxide was examined The resulting models predict variations for brightness, viscosity and peroxide consumption ranging respectively from 84.6 to 90.5% ISO, from 890cm 3 /g to 819cm 3 /g, and 26.2% to 51.6%. The reached physical properties are similar to those of ECF pulps. COD and color in effluent are, respectively, 65.33 kg O2 /tdp and 30.16 kg Pt/tdp.
Optimization of Hydrogen Peroxide Stage in TCF Bleaching Sequences of Hardwood Kraft Pulps, 1996 Pul