Cleaner approach for medium consistency eucalyptus slab pulp production using ozone bleaching under turbulent mixing

JOURNAL OF CLEANER PRODUCTION

卷:276

Article

Zhang, Xi¹  Li, Jun¹  Gong, Jie^1,4  Kuang, Yishan¹  He, Shuaiming³  Xu, Jun¹  Mo, Lihuan¹  Man, Yi¹  Zhu, Wenyuan²  Song, Junlong²  Song, Tao^1,2 

[1] South China Univ Technol, State Key Lab Pulp & Paper Engn, Guangzhou 510641, Peoples R China

[2] Nanjing Forestry Univ, Jiangsu Prov Key Lab Pulp & Paper Sci & Technol, Nanjing 210037, Jiangsu, Peoples R China

[3] Univ Maryland, Dept Mat Sci & Engn, College Pk, MD 20742 USA

[4] South China Univ Technol, Sch Environm & Energy, Guangzhou 510006, Peoples R China

关键词: Eucalyptus slab;    Medium consistency pulp;    Ozone bleaching;    Turbulent mixing;    Total chlorine free;   

DOI  :  10.1016/j.jclepro.2020.124201

来源: Elsevier

【 摘 要 】

Eucalyptus slab (ES), a cellulosic waste from wood processing is abundant and can be utilized for the pulping in many wood scarce countries. However, during chlorine dioxide (ClO2) bleaching, which is the current applied bleaching technique for medium consistency eucalyptus slab pulp (MC-ESP), toxic absorbable organic halides (AOX) is still generated, causing pollution to the water environment. Applying ozone gas (O-3) to replace ClO2 for MC-ESP bleaching is a promising alternative way since O-3 is a clean and powerful oxidizing agent but not producing AOX pollutant. In this work, the influences of the three most important O-3-bleaching factors, i.e., O-3-concentration, O-3-dosage and mixing intensity to the bleaching properties of MC-ESP was systematically evaluated. It was found that increasing of O-3-concentration and O-3-dosage greatly improved the properties of MC-ESP. Turbulent mixing intensity had a effective effect on improving O-3-bleaching of MC-ESP. The high O-3-concentration (170 mg/L), 1.0% O-3-dosage and 1200 rpm rotational speed were found to be optimum conditions for O-3-bleaching of MC-ESP. Under this condition, the brightness, kappa number and viscosity of the pulp obtained were similar or even better than those of the ESP after bleaching with similar or higher ClO2-dosage, however, without generating toxic AOX and with lower pollution load of effluent. This research provided important supports for the development of MC-ESP cleaner production by reducing the pollutant from ClO2 bleaching. Such approach of using wood processing waste as raw material, O-3 gas as AOX-free bleaching agent could provide the excellent options for eco-friendly pulp production. (C) 2020 Elsevier Ltd. All rights reserved.

【 授权许可】

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