Studies On Displacing Pulping Of Reed And Chlorine-free Bleaching

In this paper, wet cleaning system of reed, pulpabilities of reed in conventional Soda-AQ and displacing Soda-AQ pulping were studied. Effects of pulping factors on the resultants were studies. In addition , bleachability of this two reed pulps was also researched. The results shows that: After wet cleaning system , dust and fine were removed .this increased the pulpabilities of raw materials. As a kind of AQ, additive CT-i can clearly increase delignification , and protection of cellulose and hemicelluloses is also enhanced .the quantity of 0.05% is equal to that of 2% alkali. The content of HUA in conventional Soda pulping is little the degree of it is iumollg. Compared to conventional Soda-AQ pulping ; displacing pulping decreases the consumption of energy, reduces the number of K1VInO4, increases the brightness of pulping , which means the pollutant loads of bleaching effluent would be decreased . All strength properties of displacing pulp are better than that of conventional . The content of Si02 in black liquor is greatly cut down . But displacing cooking requires slightly higher alkali charge than conventional. Bleachability of both of pulps is very well, through ECF bleaching and TCF bleaching , the pulps obtain high brightness. Oxygen delignification can effectively remove the residual lignin in pulp and increase brightness with the viscosity decreased little . Reinforced-oxygen-delignification with 11202 can improve little . Reinforced-oxygen-delignification with H202 can improve the degree and selectivity of delignification . H202 bleaching as the final bleaching stage is very veil, it can not only improve the brightness , but also save bleaching cost. Through bleaching stage QOpDP, the final brightness of displacing reed pulp achieve 85%ISO...