Study On Xvlanase Aided Bleaching

Using Xylanase to pulp pretreatment can effectively reduce the consumption of chemicalsduring follow-up bleaching period, increase pulp brightness and brightness stability, improve pulpphysical properties and reduce environmental pollution.In this paper, study object is a kind of new alkaline Xylanase researched and developedindependently by a biological incorporate company. We analyzed and identified the parameter ofXylanase XYN-S assisting aspen KP pulp during HP bleaching and influence on chlorineconsumption in following bleaching. Beside, we compared and analyzed effects of five kind of newalkaline Xylanase assisting aspen/reed pulp in CEPH bleaching under plant techincal conditions, andfound a Enzyme sample which is suitable for plant application. The main research results are asfollows:The best plan for Xylanase XYN-S pretreating pulp is: Enzyme amount12U/g and60minEnzyme action time,8ph value and60℃temperature for Enzyme pretreatment. In this condition,pulp brightness is78.45%ISO, post color number is0.82, tensile index is23.58N·m/g,tear index is4.7mN·m~2/g. Under the premise of not reducing brightness, it can decrease33%effective chlorineconsumption in H peroid and improve bleached pulp physical properties.Using scanning electron microscope to observe pulp surface, we found that aspen pulp fibersurface becomes rough and there was obvious cracks. And after pretreatment by Xylanase, the fibersurface got apparent exfoliation. Measuring Xylanase processed liquid by Uv-vis spectrophotometer,we found that a bsorption capacity of Phencyclidine UV absorption band wa higher than that ofblank sample. That meant Xylanase pretreatment destroyed LCC structure in pulp, part of Lignin gotdissolved.Just considering of experiment result, Xylanase XYN-4and XYN-5are most effective toassist pretreatment bleaching. And under give conditions, using Xylanase XYN-4in pretreatment,pulp brightness is80.27%ISO,post color number is0.99, tensile index is36.27N·m/g, tear index is6.3mN· m2/g., yield rate is88.1%; using Xylanase XYN-5in pretreatment, pulp brightness is80.74%ISO, post color number is1.07, tensile index is35.67N·m/g, tear index is5.3mN· m2/g, yieldrate is88.1%. Under the premise of not reducing brightness and best Enzyme consumption amount,all kind of Enzyme samples can decrease25%effective chlorine consumption in chlorinated period.In this paper, the new alkaline Xylanase XYN-S was firstly applied in HP bleaching of aspenKP pulp. That provide experiment data for biological bleaching which advance and developXylanase, and provide new thought for energy conservation and emission reduction of paper-makingindustry.