Enzymatic Chemical Pulping of Wheat Straw (Part III):Pulping of Wheat Straw Pretreated with Xylanase and Black Liquor

Wheat straw was treated sequentially with crude xylanase and black liquor then cooked by soda process. Pulping of wheat straw pretreated with xylanase and black liquor was studied in this paper. Compared to the controls, xylanase pretreatment causes pulp kappa number decrease (decreased by about 2 units), and residual alkali concentration of black liquor increase under identical pulping conditions, but little affects the yields of screened pulps. Increasing effective alkali concentration of black liquor in black liquor pretreatment stage has positive effect on reduction of kappa number of enzymatic chemical pulps in the condition oflow cooking alkali charge, but little influence on kappa number when alkali charge is higher than 8% (based on NaOH) in cooking.