Production practice of total chlorine free clean bleaching bagasse pulp

Abstract

The experimental research, process design and production practice of total chlorine free OpQPo bleaching bagasse pulp were introduced in this paper. The results showed that Kappa number decreased from 14.0-15.0 to 7.0-7.3 with a 50%-51% removal of residual lignin, and pulp brightness increased from 42%-45%(ISO) to 58%-60%(ISO) after a strengthened oxygen delignification. The production practice showed a better performance than that in lab. After subsequent pretreatment and pressurized hydrogen peroxide bleaching, the final pulp brightness was beyond 80% and the viscosity was over 800 mL/g. The pulp quality was much better than traditional Chlorine-Alkali Extraction-Hypochlorite(CEH) bleached pulp. Moreover, adsorbable organic halides (AOX) was not generated any more in the bleaching process. The wastewater was only discharged in chelating pretreatment (Q) stage and easily treated to meet the critical discharge standard due to its lower chromaticity and lower pollution load. In contrast to the traditional bleaching, no additional investment was needed in this new technology. Besides, the production procedure was flexible and the operation was stable. The investment of main equipments was about ¥13.55 million yuan.