双螺旋挤压改良的竹材硫酸盐法蒸煮工艺的研究

Study on Kraft Cooking Technology of Bamboo with Double-screw Extrusion Improvement

关键词:  竹浆  硫酸盐法蒸煮  预处理  双螺旋搓丝

Key Words:bamboo pulp  kraft cooking  pretreatment  double helix twisting

摘要:本研究通过对竹片进行双螺旋挤压预处理，再进行硫酸盐法蒸煮，以提高硫酸盐法蒸煮效能。结果表明，采用双螺旋搓丝揉搓机，机内压缩比1∶3对竹片搓丝预处理，在相同的蒸煮工艺（用碱量18%（以Na₂O计）、硫化度20%（以Na₂O计）、液比1∶4、蒸煮最高温度168 ℃、升温时间150 min、保温时间90 min）下，经预处理所得纸浆的细浆得率较未经预处理时提高了1.3个百分点，卡伯值下降了5.2个单位，黏度提高了9 mL/g。对经预处理所得纸浆进行蒸煮工艺的进一步优化，结果表明，在蒸煮用碱量降低1个百分点、蒸煮最高温度降低6 ℃的情况下，细浆得率较未经预处理时提高了9.1个百分点，卡伯值下降了0.8个单位，黏度提高了96 mL/g。

Abstract:In this study， bamboo chips were pretreated by double-screw extrusion and then cooked by kraft method to improve the efficiency of kraft cooking. The results showed that the yield of fine pulp increased by 1.3 percentage points， the Kappa value decreased by 5.2 units and the viscosity increased by 9 mL/g by using twin-screw extruder to twist with the internal compression ratio of 1∶3 under the same cooking process （alkali of 18% （in Na₂O）， sulfurization of 20% （in Na₂O）， liquid ratio of 1∶4， highest cooking temperature of 168 ℃， heating time of 150 min， holding time of 90 min）. Then， the cooking process of pretreated bamboo was further optimized. The results showed that the yield of fine pulp increased by 9.1 percentage points， the Kappa value decreased by 0.8 unit and the viscosity increased by 96 mL/g when the alkali consumption was reduced by 1 percentage point and the highest cooking temperature was reduced by 6 ℃.