论文总字数：29555字

摘 要

木质素是生物质的三种组分之一，在自然界中储量丰富，但其较难被利用，近年来国内外科研人员对木质素的高效利用做了许多研究。木质素的化学结构表明，其可以通过降解成为许多化学品生产来源，具有极高的商业价值和开发潜力。木质素因取材和提取方法不同而具有多种复杂结构，而且其热解过程受多种因素影响。木质素催化热解行为特性的研究可以帮助我们提高木质素的利用效率和提高某些目标产物的产率。本文以杨木木质素为原料，在三种不同催化剂条件和不同的升温速率下，采用热重红外联用技术(TG-FTIR)与热裂解气相色谱-质谱联用技术(Py-GC/MS)，了解其催化热解特性。

首先，通过TG-FTIR技术研究了升温速率和催化剂对木质素转化率和动力学特性的影响。研究发现，升温速率对木质素的最终转化率的影响较小，最佳的升温速率为20 ℃ / min，随着升温速率的增大，木质素的最大失重温度点右移。木质素的热解过程可以分为脱水阶段、初步热解阶段和主要热解阶段，催化剂的存在降低了木质素的活化能，从 57.314KJ至468.716KJ/mol，降为为43.038KJ/mol至223.954KJ/mol使木质素的初步热解阶段和主要热解阶段分化更明显，并提高了最终转化率。

其次，通过Py-GC/MS技术研究了不同催化剂对木质素热解产物分布的影响。通过分析发现，催化剂条件下，木质素的热解产物种类增加。木质素的热解产物以酚类化合物为主。HZSM-5对酚类化合物具有最高的选择性。催化剂HZSM-5和β对芳香烃类化合物的生成具有较强的选择性，分别提高了14.09%和9.99%，而且催化剂HZSM-5能促进生成分子量更小、更稳定的芳香类化合物。催化剂β对环丙基甲醇的选择性提高8.29%。

关键词：木质素催化，热解，TG-FTIR，Py-GC/MS

Abstract

In recent years, researchers have done lots of research on the efficient utilization of lignin. Chemical structure of lignin indicates that it can be degraded into many sources of chemical production, with high commercial value and development potential. Lignin has a variety of complex structures due to different materials and extraction methods, and its pyrolysis process is affected by many factors. The study of lignin catalyzed pyrolysis behavior can help us to improve the efficiency of lignin utilization and increase the yield of certain target products. In this paper, thermogravimetric analysis (TG-FTIR) and pyrolysis gas chromatography-mass spectrometry (Py-GC / MS) were carried out under three different catalyst conditions and different heating rates using poplar lignin as raw material to understand its catalytic pyrolysis characteristics.

First, the effect of temperature increase and catalyst on lignin conversion and kinetics was studied by TG-FTIR technique. It was found that the rate of temperature increase had a small effect on the final conversion rate of lignin, and the optimum heating rate was 20 ℃ / min. With the increase of heating rate, the maximum weight loss temperature of lignin was shifted to the right. The pyrolysis process of lignin can be divided into dehydration stage, preliminary pyrolysis stage and main pyrolysis stage. The existence of catalyst reduces the activation energy of lignin, which makes the lignin initial pyrolysis stage and the main pyrolysis stage more obvious and increased the final conversion rate.

Second, the effects of different catalysts on the pyrolysis of lignin were studied by Py-GC / MS. The results showed that the pyrolysis product of lignin increased under the catalyst condition. The pyrolysis products of lignin are based on phenolic compounds. HZSM-5 has the highest selectivity for phenolic compounds. The catalyst HZSM-5 can promote the formation of smaller and more stable aromatic compounds. Therefore, the catalytic effect of HZSM-5 on aromatic compounds is the best. The catalyst β has high selectivity for cyclopropyl methanol.

Key words: lignin, catalyzed pyrolysis, TG-FTIR, Py-GC / MS

目 录

摘 要 I

Abstract II

第一章 绪论 1

1.1课题研究背景及意义 1

1.2国内外木质素研究进展 2

1.2.1木质素结构研究 2

1.2.2木质素的分解 3

1.2.3木质素催化热解 4

1.3课题研究目的与研究内容 5

1.3.1研究目的 5

1.3.2主要的研究内容 5

第二章 木质素的热重红外实验与分析 7

2.1引言 7

2.2木质素的热重实验与分析 7

2.2.1热重实验 7

2.2.2纯木质素的热重分析 8

2.2.3木质素与催化剂HZSM-5的热重分析 9

2.3 热解动力学 10

2.4 本章小结 14

第三章 木质素的热裂解气气相色谱-质谱实验与分析 15

3.1 引言 15

3.3 Py-GC/MS实验与分析 15

3.3.1 Py-GC/MS实验 15

3.3.2 Py-GC/MS实验分析 16

3.4 本章小结 24

第四章 结论与展望 26

4.1 结论 26

4.2 展望 27

参考文献 28

致 谢 31

第一章 绪论

1.1课题研究背景及意义

国家统计局的2016年中国统计年鉴显示，原煤、原油及天然气这三种主要能源占我国能源消费总量的比重分别是64.0%、18.1%和5.9%，而一次电力及其他能源仅占12.0%。2015年，在全国338个地级以上城市中有265个城市环境空气质量超标，超标城市达到78.4%，许多城市都出现了雾霾天气频发的现象。在全国480个监测降水的城市（区、县）中，出现酸雨的城市比例为40.4%，酸雨区面积约72.9万平方千米，占国土面积的7.6%，对国民经济造成巨大损失，而二氧化硫的过度排放是主要影响因素^[1]。空气污染不仅对我们的日常生活造成影响，而且还严重危害我们的健康，引发各类呼吸系统，心血管系统疾病。

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