基于螺旋挤压-GVL/水/酸两步预处理的溶解浆联产糠醛和木质素

Co-production of Dissolving Pulp, Furfural and Lignin Based on Spiral Extrusion-GVL/Water/Acid Two-step Pretreatment

关键词:  桉木  溶解浆  预处理  糠醛  木质素

Key Words:eucalyptus  dissolving pulp  pretreatment  furfural  lignin

摘要:针对目前溶解浆生产过程中存在的半纤维素和木质素利用率低、溶解浆质量有待提升等问题，本研究基于螺旋挤压耦合γ-戊内酯（GVL）/水/酸预处理，提出绿色环保的溶解浆联产糠醛和木质素的工艺。结果表明，桉木经螺旋挤压-GVL/水/酸两步预处理（150 ℃下反应1.5 h），蒸煮用碱量8%，漂白工艺OQP₁P₂，制备出α-纤维素含量为96.5%、白度为84.0%的高品质溶解浆；水解液分离木质素后，以甲基异丁基酮（MIBK）/H₂O-NaCl为催化体系，商业离子交换树脂为催化剂，于180 ℃下催化木糖水解液2 h，糠醛最大得率为96.0%；GVL木质素S/G比为4.81，保留一定含量的β-O-4键（22.6%）。经物料衡算，每100 g桉木可生产37.2 g溶解浆、6.2 g糠醛（理论值10.2 g）和16.4 g的GVL木质素。

Abstract:There exist some problems in the production process of dissolving pulp， such as low utilization of hemicellulose and lignin， and the low quality of dissolving pulp.This study based on the spiral extrusion combined with γ-valerolactone （GVL）/water/acid pretreatment， a green and environment-friendly process for the co-production of dissolving pulp， furfural， and lignin was proposed.The results showed that high-grade dissolving pulp was obtained with α-cellulose content of 96.5% and brightness of 84.0% by the spiral extrusion combined with GVL/water/acid pretreatment at 150 ℃ for 1.5 h， 8% alkali charge for cooking， and bleaching process OQP₁P₂.After the separation of lignin by hydrolysate， the maximum furfural yield was 96.0%， which was obtained by catalyzing xylose hydrolysate using methyl isobutyl ketone （MIBK）/H₂O-NaCl as the catalytic system and commercial ion exchange resin as the catalyst at 180 ℃ for 2 h. The S/G ratio of Kraft lignin was 4.81， and a certain amount of β-O-4 linkage was retained （22.6%）. According to material balance， 37.2 g dissolving pulp， 6.2 g furfural （theoretical value 10.2 g） and 16.4 g lignin for every 100 g of eucalyptus chips.