采用冷碱抽提工艺改善溶解浆

Improving the Cellulose Purity of Dissolving Pulp by Cold Caustic Extraction

关键词:  溶解浆  α-纤维素  冷碱抽提  半纤维素  聚木糖酶

Key Words:dissolving pulp  α-cellulose  cold caustic extraction (CCE)  hemicellulose  xylanase

摘要:纤维素纯度是溶解浆质量的首要要求。本研究采用冷碱抽提工艺，对溶解浆进行纯化处理，探讨了冷碱抽提主要工艺条件对抽提效果的影响；并与聚木糖酶处理工艺进行对比。结果表明，碱浓是影响抽提效果的最主要因素，在碱浓22%、浆浓20%、温度35℃、时间1 h抽提条件下，某预水解硫酸盐阔叶木溶解浆的α-纤维素含量由94.84%提高至98.51%；冷碱抽提对聚木糖类半纤维素具有很高的选择性,聚葡萄糖甘露糖类半纤维素需要冷碱抽提碱浓达到10%以上开始溶出；冷碱抽提在提高溶解浆纤维素纯度方面的作用明显优于聚木糖酶处理。

Abstract:Cellulose purity is of critical importance for dissolving pulp. The cold caustic extraction (CCE) process was employed to purify dissolving pulps in this study. When a pre hydrolysis kraft based hardwood dissolving pulp was treated under the CCE conditions of 22% NaOH solution, 20% pulp consistency, 35℃， and 1 h duration, its α cellulose content was increased from the original 94.84% to 98.51%.NaOH concentration was proved the dominator affecting the CCE result. CCE showed very high selectivity in extracting the xylan hemicellulose from pulp samples, while the glucomannan hemicellulose could only be removed under the NaOH concentrations above 10%. CCE was more effective than xylanase treatment in purifying dissolving pulp.