“酸碱联产与再生循环”在秸秆高值化加工中的应用
文献类型：学位论文
| 作者 | 孙勇 |
| 学位类别 | 博士 |
| 答辩日期 | 2007-09-14 |
| 授予单位 | 中国科学院过程工程研究所 |
| 授予地点 | 过程工程研究所 |
| 导师 | 李佐虎 |
| 关键词 | 酸碱联产与再生循环 秸秆 组份分离 高值化 木质素 |
| 其他题名 | The Application of Process of The Acid-Alkali Coupled Production And Regeneration to The High Valued Conversion of Corn Straw |
| 学位专业 | 生物化工 |
| 中文摘要 | “酸碱联产与再生循环” 是中国科学院过程工程研究所李佐虎教授近十多年新开创的一项新技术。该技术的一个重要应用方向是针对秸秆木质纤维素进行高值化加工。木质纤维素三组份分离的效率与成本是其高值化加工的基础，本研究基于该技术能低成本联产酸（盐酸、磷酸）、碱（氨、KOH）以及强氧化剂（二氧化氯）等，提出一种酸碱联合使用对秸秆木质纤维素三组份进行高效分离的新方法。同时，本研究还分别探讨了一种利用秸秆木质素为前驱，以“酸碱联产与再生循环”新技术所生成的钾碱（K2CO3、KOH）和钠碱（Na2CO3、NaOH）为活化剂制备高比表面积活性炭的新方法以及一种以木质素自身芳香环为主体，经酸碱联产工艺产出的强氧化剂改性制备树脂的新方法。 主要研究内容与结论如下： （1）稀酸水解玉米秸秆半纤维素的实验表明，木糖生成和降解活化能分别为116.0、59.5 kJ/mol；最佳水解条件下水解液中木糖含量>21 g/L，糠醛含量<1.46 g/L，半纤维素脱除率可达90%以上。 （2）使用NH4OH+KOH分离脱除半纤维素后的玉米秸秆中的纤维素与木质素，确定最佳分离工艺条件，得到木质素大量脱除段动力学方程。 确定酸碱对玉米秸秆三组份耦合分离的最佳工艺方案：2%的稀盐酸于120℃下水解50 min（液固比10：1），得到木糖水解液（木糖含量>21 g/L，糠醛含量<1.46 g/L）；利用脱除半纤维素后的玉米秸秆在（NH3 25%、KOH 5 %、液固比8：1、温度150℃、反应时间30 min条件下）进行反应，可将玉米秸秆中木质素和纤维素（得率>40%）有效分离。使用磷酸对黑液进行酸析分离木质素，pH值为2时，木质素最终得率>60%。所得酸析滤液中含有N、P、K（11.23、17.79、2.51 g/L）以及有机质（木质素和纤维素的降解产物），制作成全价有机复合肥（液或固）。 （3）提出以酸析木质素为原料经预炭化再K2CO3活化的两步法制备高比表面积活性炭的新工艺。通过考察活化方法、不同活化剂、活化剂用量、活化温度等参数，确定最佳工艺条件：于流化床中350℃下预炭化5 min，将所得炭粉与K2CO3 (1：1 w/w)混合，再转置于管式炉内800℃活化60 min。活性炭最佳制备条件下的BET比表面积、微孔体积、总孔体积分别可达1410 m2•g-1、0.49 cm3•g-1、0.78 cm3•g-1。 最佳工艺条件下的活性炭吸附苯酚、硝基苯以及Cr(VI)的Langmuir饱和吸附量分别为：137.1、168.2、53.1 mg•g-1，表明具有较好的吸附性能。 （4）提出以玉米秸秆木质素为主体制备改性树脂的新工艺，改变木质素在制备树脂过程中只能充当添加剂以部分取代苯酚的现状。利用二氧化氯对木质素芳香环基团进行选择性氧化，生成带有羰基的邻醌或对醌形式的活性基团，使用共轭双烯化合物呋喃甲醇与氧化木质素发生Diels-Alder反应，生成木质素改性树脂。确定制备树脂的最佳工艺条件；得到树脂粘流活化能为142.26 kJ•mol-1；改性呋喃甲醇木质素树脂对于无机酸碱均有较好的耐受性；通过与糠醛树脂比较，其多项指标与糠醛树脂相当。 |
| 英文摘要 | The process of the acid-alkali coupled production and regeneration (AACPR) developed by professor Li Zuohu during the last decade from Institute of Process Engineering, Chinese Academy of Sciences is a significant fundamental innovative technology. One of its main applications is the high value conversion of the straw. The efficiency and cost of fractionation of lignocellulose is the precondition of its high value conversion. In this study, three main compositions (hemicellulose, lignin and cellulose) of cornstraw material was effectively fractionated by the use of the products of acid (HCl, H3PO4), alkali (NH3, KOH) and oxidizer (ClO2) from the process of acid-alkali coupled production and regeneration. Among the processes of high value added conversion of lignocellulose, the conversion of cellulose to the pulp is the most profitable process. The study of high value conversion of acid precipitated lignin from the pulp processing is correspondingly very important. Because of this, this research also studied a new process of preparing an activated carbon with high specific surface area using cornstraw acid precipitated lignin as precursor by the use of potassium alkaline (K2CO3, KOH) and sodium alkaline (Na2CO3、NaOH) as activator, and a new process of preparing a resin using lignin as main structural units by the modification of strong oxidizer ClO2. The main study contents and the conclusion are as followings: 1. The activation energy of xylose releasing and degrading are 116.0 and 59.5 kJ/mol, respectively. The xylose and furfural concentration under optimal condition are 21 g/L and 1.46 g/L, respectively. The rate of hemicellulose removal can be over 90%. 2. The optimal fractionation condition by NH4OH+KOH is obtained, the kinetic delignification formula of cornstraw (with hemicellulose is removed by acid hydrolysis) is obtained. The optimal fractionation process is obtained based upon the process of the acid-alkali coupled production and regeneration: using 2% dilute HCl under 120℃ to hydrolysis the hemicellulose from conrstraw for 50 min with liquid solid ratio of 10:1, the resultant solution contains xylose >21 g/L and furfural <1.46 g/L. The cornstraw with hemicellulose removed by dilute acid hydrolysis was then cooked in NH4OH+KOH combined system, the optimal cooking condition is following: NH3 25%, KOH 5%, liquid to solid ratio 8:1, 150℃ with temperature maintaining for 30 min. The pulp (>40%) and lignin (>60%) were subsequently obtained. The fractionation effluent contains N, P and K nutritions and organic compounds. 3. A new process of producing activated carbon with high specific surface area by two-step K2CO3 activation is developed in this study. The different operational parameters such as one-step chemical activation and two-step chemical activation, different chemical activators, amount of activator, activation temperature etc were closely investigated. The optimal preparation conditions of producing carbon are following: precarbonized the lignin in the fluidized bed reactor at 350℃ for 5 min, then impregnated the char with K2CO3 (1:1 mass to mass) and activated the mixture at 800℃. The BET specific surface area, micropore volume and pore volume of the carbon produced under optimal condition could reached 1410 m2•g-1,0.49 cm3•g-1 and 0.78 cm3•g-1, respectively. The maximum adsorption capacity of L800 in removing of phenol, nitrobenzene and Cr(VI) are 137.1,168.2 and 53.1 mg•g-1, respectively, which shows good adsorption performance. This high valued conversion process of lignin makes it having wide area of application. 4. A new process of using cornstraw lignin as main structural units is developed in this research. The lignin is oxidized by chlorine dioxide then modified with furfural alcohol through the reaction of Diels-Alder. The optimal conditions of producing modified lignin resins are obtained. The viscous flow activation energy of lignin resin reached 142.26 kJ•mol-1. The modified lignin resin shows good toleration against the corrosion of inorganic alkali and acid. The characteristics of this modified lignin resin is comparable to that of furfural phenol resin's. |
| 语种 | 中文 |
| 公开日期 | 2013-09-13 |
| 页码 | 144 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1112]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 孙勇. “酸碱联产与再生循环”在秸秆高值化加工中的应用[D]. 过程工程研究所. 中国科学院过程工程研究所. 2007. |
入库方式： OAI收割
来源：过程工程研究所
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