New Technologies In Pulp bleaching South China University of Technology
South China University of Technology New Technologies In Pulp Bleaching
Introduction oXYgen Delignification Ozone delignification a Peroxide Bleaching Peracid Bleaching a Hydrosulfite Bleaching ■Ch| urination a Chlorine Dioxide Bleaching a Enzyme Treatment of Pulp(Biobleaching) South China University of Technology
South China University of Technology Introduction Oxygen Delignification Ozone Delignification Peroxide Bleaching Peracid Bleaching Hydrosulfite Bleaching Chlorination Chlorine Dioxide Bleaching Enzyme Treatment of Pulp(Biobleaching)
INTRODUCTION ■ Objectives ● Brightness ○c| earliness O Purification-dissolving grade a Historical background ■ Major concerns ◇ Costs◇ Environmental◇ Energy South China University of Technology
South China University of Technology INTRODUCTION Objectives ●Brightness ●Cleanliness ●Purification-dissolving grade Historical background Major concerns ◇Costs ◇Environmental ◇Energy
Functions, advantages and disadvantages of bleaching chemicals Chemical Function Pulp Advantag Disadvantages e Cl2 Oxidize andC Effective Organochlorine chlorinate economical delignification formation good particle removal highly corrosive Naocl Oxidize c Easy to make Can cause loss of decolorize. and and use: low pulp strength Ca(Ocl)2 solubilize lignin cost chloroform formation CIO 1)Oxide, c Achieve high Must be made on decolorize and brightness solubilize lignin without loss of site: cost: some 2)In small pulp strength;I organochlorine amounts with cI2 good particle formation; highly protects against bleaching corrosive cellulose degradation
Chemical Function Pulp Advantag e Disadvantages Cl2 Oxidize and chlorinate C Effective, economical delignification; good particle removal Organochlorine formation; highly corrosive NaOCl Ca(Ocl)2 Oxidize, decolorize, and solubilize lignin C Easy to make and use; low cost Can cause loss of pulp strength; chloroform formation ClO2 1)Oxide, decolorize and solubilize lignin 2) In small amounts with Cl2; protects against cellulose degradation C Achieve high brightness without loss of pulp strength; good particle bleaching Must be made onsite; cost; some organochlorine formation; highly corrosive Functions, advantages and disadvantages of bleaching chemicals
Functions, advantages and disadvantages of bleaching chemicals Chemical Function Pul Advantage disadvantag p es Oxidize and Low chemical Requires significant solubilize lignin cost; provides capital equipment chlorine-free when used in large effluent for amounts potential recovery loss of pulp strength H2O2 Oxidize and C or Easy to use; High chemical decolorⅰze M Low capital cost: Poor lignin cost particle bleaching Can cause loss of pulp strength O3 Oxidize Effective Must be made decolorize and provides on-site: cost: poor solubilize lignin chlorine-free particle bleaching effluent for and pulp strength recovery
Chemical Function Pul p Advantage s disadvantag es O2 Oxidize and solubilize lignin C Low chemical cost; provides chlorine-free effluent for recovery Requires significant capital equipment when used in large amounts; potential loss of pulp strength H2O2 Oxidize and decolorize lignin C or M Easy to use; Low capital cost High chemical cost; Poor particle bleaching; Can cause loss of pulp strength O3 Oxidize, decolorize and solubilize lignin C Effective, provides chlorine-free effluent for recovery Must be made on-site; cost; poor particle bleaching and pulp strength Functions, advantages and disadvantages of bleaching chemicals