论文总字数：41503字
摘 要
生物质快速热解能够将生物质在几秒钟转化成数百种含氧化合物，被认为是目前很有前景的生物质利用技术。热解得到的化合物中很多种价值较高的化学品，如果能够将它们提纯利用，能够显著提高生物质热解路线的经济效益。但是这些化学品的含量较低，选择性较差，提纯成本较高。基于此背景，本论文首先对不同种类的生物质进行热解研究，获得何种原料能够产生哪些产量较高的化学品，然后对热解工况进行优化，最后此基础上向生物质中加入适当的添加剂，实现对这些化学品的定向富集。
本论文首先对梧桐科梧桐属，豆科花生属，杨柳科柳属，乔本科玉米属等科属的17种生物质原料进行了Py/GC/MS快速热解研究。结果表明，热解产物的主要分为酮，酸，酚，呋喃四类产物。选出较有代表性的四种原料进行下一步的研究，他们分别为枇杷树枝，香樟树枝，花生壳和玉米芯。玉米芯适合生成呋喃类产物如2,3-二氢苯并呋喃，其选择性可达到26.2%。花生壳可产生一定量乙酸，其选择性为13.7%。可做为产生酚类产物的原料，生成的2-甲氧基苯酚和2-甲氧基, 4-乙烯苯酚的选择性分别为13%和11.2%。枇杷树枝的主要产物为乙酸，其选择性为23.21%。香樟树枝的主要产物为乙酸和1,6-脱水-β-D-吡喃型葡萄糖，其选择性分别为11.9%和14.4%。
对热解某种化学品产率较高的生物质进行热解工况研究，增加该种化学品产率和选择性，然后在最有热解工况下添加不同的添加剂，进一步富集高化学品。结果表明，枇杷树枝添加磷酸三钾后，丙酮，2,6-二甲氧基苯酚选择性增加近一倍。香樟树枝加入磷酸三钾后，丙酮增加至12.8%。加入磷酸三钾使酮类总产量选择性增加了4倍。酚类产物中2-甲氧基-苯酚，2-甲氧基-4-乙烯苯酚的选择性增加明显，均由5%提高至11%左右。磷酸三钾，磷酸三钠，磷酸三钙添加热解花生壳均可以不同程度地提高丙酮的选择性。磷酸三钠和磷酸三钙还会促进羟基丙酮选择性的增强。氯化锌和氯化铁催化热解玉米芯都能够有效提高呋喃类产物的产量和选择性，氯化锌使糠醛的选择性由3%增加至38%，氯化铁使糠醛的选择性增加至40%。加入氯化铁后产物出现呋喃，其选择性为16%。总体上添加氯化铁的热解效果更好，更有利于呋喃类产物的生成。
关键词：生物质；选择性热解；Py-GC/MS；化学品
The research of biomass selective pyrolysis for chemical preparation
03011418 Yixuan Jia
Supervised by Huiyan Zhang
Abstract:
Biomass fast pyrolysis is able to turn biomass into thousands of oxygen compounds within a few seconds and is now assumed the most promising biomass utilization technology. Many of the compounds gained from pyrolysis process are higher value chemicals. With purification, the economic benefit of biomass pyrolysis route could be greatly improved. However, most of those chemicals have the characteristics of low content and bad selectivity, thus the purification cost is relatively high. Based on those backgrounds, this paper firstly chooses different kinds of biomass for the research of fast pyrolysis process to know what kind of biomass material is suitable for what kind of chemicals with high yield. Then the condition of pyrolysis is optimized. In the end, moderate amount of additive is added into biomass materials to achieve the directional enrichment of chemicals.
17 kinds of biomass materials are pyrolysed with the equipment of Py-GC/MS. The result shows that the main products of pyrolysis are classified into four categories: ketones, acids, phenols and furans. Choose loquat twig, camphor tree branch, corncob and peanut shell for future use. Corncob is suitable for the production of furans such as 2,3-dihydro- Benzofuran, the selectivity is 26.2%. Peanut shell could also produce acetic acids, and the selectivity is 13.7%. It also can be used as the material for phenols and the selectivity of 2-methoxy-Phenol and 2-Methoxy-4-vinylphenol are 13% and 11.2% respectively. The main product of loquat twig is acetic acid and its selectivity is 23.21%. The main products of camphor branch are acetic acid and 1,6-anhydro-β-D-Glucopyranose, the selectivity of them are 11.9% and 14.4%.
Biomass with higher yield of some chemicals is tested under different pyrolysis conditions to raise the yield and selectivity of chemicals. Then, additive is mixed with materials under the best pyrolysis condition for the enrichment of the products. The result shows that, the selectivity of acetone and 2,6-dimethoxy-Phenol doubled with the addition of K3PO4 to loquat twig. By adding K3PO4 to camphor branch, the selectivity of acetone rises to 12.8% and the total selectivity of ketones increases 4 times than before. The selectivity of 2-methoxy-Phenol and 2-Methoxy-4-vinylphenol rise from 5% to 11%. The addition of K3PO4, Na3PO4 and Ca3(PO4)2 for peanut shell pyrolysis can all increase the selectivity of acetone with different degrees. Na3PO4 and Ca3(PO4)2 could also help enhance the rise of selectivity of 1-hydroxy-2-Propanone. Both ZnCl2 and FeCl3 could raise the selectivity and yield of furans. The furfural selectivity of corncob with ZnCl2 increases from 3% to 38% and with FeCl3, the selectivity reaches 40%. The addition of FeCl3 enhance the production of furan, whose selectivity is 16%. Totally, the effect of pyrolysis with FeCl3 is better than with ZnCl2 for the furans selectivity is higher.
Key words: biomass; selective pyrolysis; Py-GC/MS; chemicals.
目录
摘要.............................................................................Ⅰ
ABSTRACT.........................................................................Ⅱ
目录.............................................................................Ⅲ
- 绪论.......................................................................1
1.1 课题研究背景与意义..........................................................1
1.2 国内外研究现状..............................................................1
1.2.1 生物质快速热解制备化学品................................................1
1.2.2 热解温度及热解时间对产物分布的影响......................................2
1.2.3 催化剂对生物质快速热解产物的影响........................................3
1.3 课题的研究思路和目标........................................................4
- 生物质快速热解的Py-GC/MS实验研究..........................................6
2.1 引言........................................................................6
2.2 实验部分....................................................................6
2.2.1实验原料.................................................................6
2.2.2实验装置.................................................................6
2.2.3实验方法.................................................................6
2.2.4 数据处理方法............................................................7
2.3 实验结果与讨论..............................................................7
2.3.1同种原料产物选择性对比...................................................7
2.3.2 某种产物不同原料产量对比...............................................11
2.4 小结.......................................................................13
- 热解温度和添加剂对生物质热解产物定向富集研究..............................14
3.1 引言.......................................................................14
3.2实验部分....................................................................14
3.2.1 实验原料...............................................................14
3.2.2 实验过程和实验装置.....................................................15
3.2.3 数据处理方法...........................................................17
3.3 实验结果与讨论.............................................................17
3.3.1 最佳热解温度的选择.....................................................17
3.3.2 添加剂对产物的定向富集.................................................18
3.4小结........................................................................36
第四章 结论与展望................................................................37
4.1 结论.......................................................................37
4.2 展望.......................................................................37
参考文献.........................................................................39
致谢.............................................................................43
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