Ozone and Hydrogen Peroxide Stages in Bleaching Sequences at Pilot Scale, 1996 International Pulp Bleaching Conference Proceedings

C. de Choudens, R. Angelier, C. Chirat

Domaine Universitaire

Environmental and marketing pressures have led some companies to modify their bleaching sequences. In addition to the laboratory research, some companies choose to run pilot trials for several purposes : to validate the laboratory results, and especially the chemicals usages, to measure the strength properties and the effluents characteristics of pulps bleached at a bigger scale than in the laboratory, or to test the runnability on a pilot scale paper machine. The Centre Technique du Papier pilot plant offers the opportunity to carry out all types of bleaching sequences. Conventional sequences using chlorine and chlorine dioxide, as well as ECF and TCF sequences using oxygen, hydrogen peroxide, ozone, peracids, chelating stages. After a brief description of the pilot, some examples of ECF and TCF bleaching sequences carried out on various pulp types will be given. The TCF sequences were either ozone based or peroxide based and pressurised peroxide stages were used to improve the final brightness.