麦草甲酸法制浆过程副产物成分分离及表征

发布时间：2018-05-23 13:31

本文选题：麦草 + 甲酸　；参考：《北京林业大学》2011年硕士论文

【摘要】：甲酸制浆过程在本质上是甲酸对原料化学组分的分离过程。分离后,纤维素以固态存在于蒸煮体系中,半纤维素、木素则溶于试剂中,形成黑液。分离得到的纤维素可用于造纸或其他化学工业,半纤维素可用于生产木糖醇、糖醛、添加剂等产品,木素可用于生产复合材料或作为化工原料。充分利用制浆过程副产物不仅能避污染环境,还能带来可观的经济效益,因此将溶于黑液的化学成分进行分离、纯化具重要意义。本实验以麦草为原料,探讨了甲酸蒸煮工艺条件对制浆过程的影响,研究了细胞微区木素在蒸煮过程中的溶出规律,提出了黑液中木素与碳水化合的分离方案,初步尝试了超滤膜方法分级得到的多糖。通过对麦草甲酸法制浆及其副产物分离提取工艺条件的研究,得到了甲酸法分离麦草三大主要组分的工艺条件。研究结果表明：以纸浆为目标产品的蒸煮过程其蒸煮时间不应超过120min；延长蒸煮时间,纸浆得率将逐渐降低,碳水化合物发生降解；蒸煮初期,细胞壁各部位木素均有溶出,蒸煮中后期,细胞角隅木素溶出速率高于复合胞间层木素；先沉淀分离黑液木素的分离方法,木素分离效果良好,在pH值为2.5时,木素分离得率即可达到最大；采用醇析分离糖分产物中会含有部分木素成分；所分离的多糖产物由木糖(75%)、阿拉伯糖(10%)、葡萄糖(9%)等单糖基组成；多糖分子量分布较宽,但较长蒸煮时间蒸煮后分子量较小,同时分散度也减小。研究结果对提高原料资源的利用效率以及制浆副产物的后续高价值利用奠定了基础。
[Abstract]:The process of formic acid pulping is essentially the separation process of formic acid from the chemical components of raw materials. After separation, cellulose existed in the cooking system as solid state, hemicellulose and lignin dissolved in reagent to form black liquor. The separated cellulose can be used in papermaking or other chemical industries, hemicellulose can be used in the production of xylitol, sugar and aldehyde, additives and other products, lignin can be used to produce composite materials or as chemical raw materials. Making full use of the by-products of pulping process can not only avoid environmental pollution, but also bring considerable economic benefits. Therefore, it is of great significance to separate and purify the chemical constituents dissolved in black liquor. In this experiment, wheat straw was used as raw material to study the effect of formic acid cooking process on pulping process, to study the dissolution rule of lignin in cell microzone during cooking, and to put forward the separation scheme of lignin and carbohydrate in black liquor. The polysaccharides obtained by ultrafiltration method were preliminarily tried. Based on the study of the technological conditions for the separation and extraction of wheat straw by formic acid method, three main components of wheat straw were separated by formic acid method. The results showed that the cooking time of pulps should not exceed 120 mins, the pulp yield would gradually decrease and carbohydrate degradation would occur when the cooking time was prolonged, and the lignin in all parts of the cell wall could be dissolved at the beginning of cooking. In the middle and late stage of cooking, the dissolution rate of cell corner lignin was higher than that of compound intercellular layer lignin, and the separation method of lignin from black liquor by precipitation had a good separation effect, and the maximum lignin separation rate could be achieved when pH value was 2.5. Some lignin components are found in the sugar products separated by alcohol analysis; the separated polysaccharides are composed of monosaccharide groups, such as xylose 75, arabinose 10, glucose 9); the molecular weight of polysaccharides is wider, but the molecular weight of the polysaccharides after cooking for longer cooking time is smaller. At the same time, the dispersion is also reduced. The results laid a foundation for improving the utilization efficiency of raw material resources and the follow-up high value utilization of pulp by-products.
【学位授予单位】：北京林业大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TS743.12

【相似文献】