Effect Of Enzyme Pretreatment On Beating Performance Of Unbleached Sofewood Pulp

Energy consumption is one of the main problems facing the paper industry,which to a certain extent restricts the development of the paper industry.The energy consumption of pulping softwood pulp is high,and how to reduce the energy consumption of pulping softwood pulp is an issue of great concern to papermakers.In this paper,the enzymatic pulping of unbleached softwood pulp was investigated by using cellulase,ferulic acid esterase and the synergistic action of the two enzymes to compare the differences in the effects of different enzyme treatments on the pulping promotion effect,to find the best enzyme treatment method from the perspective of energy saving,and to explore the mechanism of biological enzyme promotion pulping initially.By comparing the enzymatic beating effect of cellulase on bleached softwood pulp and unbleached softwood pulp,it was found that the best beating promotion effect was 52% for bleached pulp and 31% for unbleached softwood pulp using PFI at a beating speed of 8000 rpm.At lower enzyme dosages,the promotion effect on pulping is not very significant,but there is an increase in sheet tensile strength and breaking strength.By optimising the enzyme treatment conditions for beating unbleached softwood pulp after ferulic enzyme pretreatment,the best energy saving conditions for ferulic enzyme pretreatment were enzyme dosage 10 U/g,pH 5,temperature 50℃,pulp consistency 3% and treatment time 1 h.The beating improvement of unbleached softwood pulp with ferulic enzyme pretreatment alone was very obvious,but the effect on paper strength was higher.Comparing the three enzymatic treatments in terms of energy savings,it was found that the combined treatment of unbleached softwood pulp with ferulic acid esterase and cellulase resulted in a 51% energy saving when beating the pulp to a pulping degree of 35°SR,with no adverse effect on the physical strength of the paper.The SEM microscopic morphology of the enzymatically treated fibres showed a higher degree of fibrillation and fibrillation after cellulase treatment and a higher degree of surface structure destruction after ferulic acid ester enzyme treatment,with the synergistic treatment of both enzymes having a greater degree of fibre structure destruction than the single enzyme treatment.The comparison of the specific surface area of the fibres showed that the increase in specific surface area of the fibres after the combined treatment was higher than that of the single enzyme treated samples.The analysis of the polymerisation of the fibres showed that the ombined treatment showed the highest decrease in polymerisation and the greatest decrease in cellulose content,indicating that the effect of the cellulase enzyme was stronger than that of the single cellulase enzyme after the ombined treatment of ferulic acid esterase on the destruction of the fibre surface.Overall,the pretreatment of unbleached softwood pulp with ferulic acid esterase and cellulase had a significant effect on the promotion of pulping effect and helped to reduce the energy consumption of pulping.