Journal of South China University of Technology (Natural Science Edition) ›› 2014, Vol. 42 ›› Issue (2): 14-20.doi: 10.3969/j.issn.1000-565X.2014.02.003

• Chemistry & Chemical Engineering • Previous Articles     Next Articles

Comparison of ECF Short- Sequence Bleaching Processes for Bagasse Pulp

Li Jun He Shui- lin Li Zhi Xu Jun Mo Li- huan   

  1. State Key Laboratory of Pulp and Paper Engineering,South China University of Technology,Guangzhou 510640,Guangdong,China
  • Received:2013-07-19 Revised:2013-11-08 Online:2014-02-25 Published:2014-01-02
  • Contact: 徐峻(1979-)，男，博士，助理研究员，主要从事纸浆清洁生产技术与植物纤维功能化利用的研究． E-mail:xujun@scut.edu.cn
  • About author:李军(1972-)，男，博士，教授，主要从事纸浆清洁漂白技术与装备研究．E-mail:ppjunli@scut．edu．cn
  • Supported by:

    国家 “973” 计划项目(2010CB732205); 华南理工大学制浆造纸工程国家重点实验室开放基金资助项目(201356)

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Abstract:

In this paper,first,three typical element chlorine- free (ECF) short- sequence bleaching processes,namely D0 EpD,OpDEp and OpD,were comparatively investigated.Then,the difference in delignification rate be-tween the chlorine dioxide delignification (D0 ) and the peroxide- reinforced oxygen delignification (Op) was re-vealed,and the effect of pre- delignification on the subsequent bleaching was analyzed.Finally,the AOX (Absor-bable Organic Halides) emission and the direct chemical cost during the bleaching were discussed.The results in-dicate that (1) D0 possesses high delignification selectivity; for instance,the delignification rate reaches 40% at aClO2 dosage of only 0.8% and continuously increases with ClO2 dosage; (2) Op can not only delignify the residuallignin in pulp but also remarkably improve the pulp brightness to a value much higher than that of D0 pulp; (3)OpDEp bleaching is more effective than D0 EpD bleaching at the same chemical dosage in the subsequent bleachingbecause it may result in higher pulp brightness; (4) the final brightness of OpDEp bleached pulp is about 12 per-centage points higher than that of OpD bleached pulp; and (5) at the same pulp brightness,the AOX emitted du-ring the OpDEp bleaching is only about half of that emitted during the D0 EpD bleaching,and the direct chemicalcost of OpDEp bleached pulp is 40. 00 Yuan/t lower than that of D0 EpD bleached pulp,which means that OpDEpbleaching is of higher environmental and economic benefits.

Key words: bagasse pulp, ECF short- sequence bleaching, chlorine dioxide delignification, peroxide- reinforced oxy-gen delignification, absorbable organic halide, direct chemical cost