【作者】 刘生玉；

【导师】 谢克昌；

【作者基本信息】 太原理工大学 ， 化学工程与技术， 2004， 博士

【摘要】 煤的热转化是当前煤炭加工利用中最重要的过程，而煤热解是煤转化的最基本过程。煤无论是进行燃烧，还是气化、液化、干馏，都有煤的热解作为其初始和伴随反应，对后面的转化步骤有重要影响，煤的热解与煤的热加工技术关系极为密切，煤热解过程的深入研究对煤的热加工转化过程有直接的指导作用。本文从煤、有机显微组分、煤抽提物和具有准确分子结构模型化合物不同尺度重点研究我国典型动力煤种热解过程中其有效组分的转化特征，主要包括以下几方面内容： 1．选取了10种中国典型动力煤种，系统考察了不同热解条件下煤热解产物的分布、逸出规律、组成和性质；研究和探讨了煤中C、H、O元素不同热解温度下在产物中的分布及其变化规律。主要结论如下： 煤在热解过程中，700℃时大部分的挥发分已经释放，与此对应的是在300-700℃温度范围，气相和液相产物的产率快速增加。900℃时煤中的碳大部分残留在焦中，而H和O元素在焦中存在很少，绝大部分以焦油和气体产物的形式释放出去。在400-700℃温度范围内，焦中的碳所占的比例呈明显的下降趋势，相对应的是进入热解气体和焦油中碳呈增加趋势。400-700℃温度范围内大量的烃类气体和焦油产生，使得焦中氢迅速减少。700℃以后，焦中氢比例仍然呈下降趋势，主要是由于热缩聚反应放出氢气造成的。超过75％以上的煤中氧进入到了热解含氧气体，只有不到10％的氧进入到焦油中，焦中氧含量降低主要发生在400-700℃。热解气体中各组分的逸出规律明显不同。从10种煤的各热解产物释放随温度的变化规律看，热解产物的释放强烈依赖于热解温度，对煤阶不敏感，但是产物的释放量与煤阶密切相关。 2．采用热重分析仪和热解-红外光谱联用仪(Py-FTIR)考察了神府镜煤四氢呋喃抽提物的热解过程。热重的研究结果表明：抽提物的热解失重行为与镜煤的热解失重行为有很大不同，抽提物有两个明显的DTG峰，190℃左右时出现一个DTG峰，在439℃出现第二个DTG峰，与镜煤相比，抽提物的失重速率显著高于镜煤，且最大失重峰向低温区移动。抽提物的热解产物中脂肪烃的释放量多于镜煤，而且脂肪烃类产物释放的温度区间小，说明脂肪烃的释放更集中和快速， 太原理工大学博士学位论文但是甲烷的生成量明显少于镜煤;抽提物热解产物中有少量的co:生成，几乎没有产生CO。热解过程中抽提物易融化、膨胀。 3.对两种有机显微组分热解特性和差异进行了比较研究，实验结果表明:镜质组的失重量比丝质组大，镜质组达到最大失重速率的温度小于丝质组。镜质组热解产物中的脂肪烃含量要大于丝质组和原煤;原煤的甲烷放出最大，镜质组其次，丝质组最少。CO:的释放量由大到小的顺序是丝质组>原煤>镜质组，而且丝质组CO:释放温度范围要大于原煤和镜质组。 4.选取了12种与煤分子结构中含氧官能团相关的含氧模型化合物，系统考察这些含氧模型化合物热解特性，结合实验结果对上述含氧模型化合物的热解机理进行了分析和推断，得出了下面的结论: 芳香酸的热解机理主要是正离子型机理，自由基机理的可能性较小。酚在受热的情况下会放出HZ，并确认是由于分子中O一H键断裂而产生的，O一H键断裂后生成酚氧基(C6H50)，而且酚的热分解不会导致分子内的C一O键的断裂。可以肯定酚类的热解过程有CO的丢失，并伴随六元的芳香环变为五元环。芳香酮主要发生a碎裂，醛类的质谱行为与酮类是很相似的，也是通过。碎裂形成偶电子离子，然后通过i碎裂过程失去CO。烷氧基热解的一条路线是烷氧基中的氧以CO的形式放出，另一条路线是烷氧基中的氧形成酚轻基，失掉烷基，醚键的断裂伴随着酚轻基的形成。杂环氧的热解可以产生CO，但热分解的温度高，并伴随着环的破裂。 5.考察了高邻土、蒙脱石粘土矿物质对直链烷烃的催化裂解，结果表明，矿物质对直链烷烃的催化裂解生烃的效果是明显的，其中蒙脱石的催化作用最大。氧化钙和Y一A120。是通过吸附裂解对挥发分的释放起抑制作用。 6.芳烃上的甲基的断裂产生甲基自由基的过程需要较高的温度，与甲基苯或多甲基取代苯相比，乙基苯或更长链的烷基取代苯热解更易产生甲基自由基，产物中的甲烷量要多。更多还原

【Abstract】 Prompted by the need of non-petroleum-based fuels, coal research has reemerged to center stage today. Pyrolysis research, in particular, has gained considerable momentum because of its close connection to combustion, gasification and liquefaction. The results of scientific investigations of coal pyrolysis are the indispensable basis for technology in almost all areas of utilization of coal. In the present paper, we conducted the pyrolytic experiments of coals, macerals, coal extract and coal model compounds containing oxygen groups, respectively. The aim is to describes the distribution and evolution characteristics of pyrolysis products of used samples under different thermal conditions and present a purposely view of the relationship between a coal structure and pyrolysis reactivity. The theme includes such contents as follows:10 kinds of Chinese steam coal samples were chosen and their pyrolysis experiments were done under different conditions. Distribution and evolution characteristics of products during pyrolysis were observed. Elemental analysis, FTIR spectroscopy, GC-MS, 13C-NMR and XRD techniques were employed to characterize the tars and chars in details. Mass balance of elements C, H, O in various products produced at different temperature was obtained. The results show that the formation of volatile matter was mainly in temperature range of 400-700 ℃ and the evolution of products is functions of temperature. In bituminous coals where the weight loss is dominated by tar, the ultimate yield appears to increase very little beyond 700 ℃, while in lignites a considerable fraction of the volatiles consists of CO, CO2 and hydrocarbon gases, the ultimate weight loss continues increasing with temperature beyond 700 ℃. Almost all H and O of coal converted into volatile at 900 ℃. About 75% oxygen evolution in the gas phase oxygen, the great mass of this converted into the gas phase between 400-700℃. The conversion to tar-O was always is less than10%. Coal rank is a very important factor in the amounts of evolution of various products. The evolution characteristics of gaseous products are different.As the important part of coal organic structure, low molecular weight compound is thought to play a key role in the structure of coal and has a significant effect on the process of coal pyrolysis. The extract sample was obtained from vitrain extracted bytetrahydrofuran. The thermal decomposition behavior of vitriain and its extract were investigated by means of TG and Py-FTIR, the latter can continuously obtain IR spectra of the volatiles as the sample is heated. The TG and DTG curves of extract are different from that of vitrain. The rate of weight loss of extract is higher than that of vitrain. The maximum peak in DTG curve of extract moves towards low temperature compared with vitrain. The results of experiments using Py-FTIR shows that the amounts of aliphatic evolution of extract is higher than that of vitriain, the evolution profile indicates the evolution of aliphatic is fast. The amounts of methane and CO2 evolution from extract were lower than that of vitrain. No CO was produced from extract.Pyrolysis of macerals from Shenfu coal was performed using TG and Py-FTIR techniques. It was found that vitrinite has a lower peak temperature of evolution of volatile matter and greater weight loss rate than those of coal and inertinite. Vitrinite has higher yield of paraffin than that of coal and inertinite, while coal and inertinite give more evolution of oxygen-containing products.Because of the complex, ill-defined molecular compositions and structures of coals, and because of the multiplicity of possible reactions when coal undergo pyrolysis, pure organic compounds are often used as models of some facet of the nature of coal. Understanding the reactivity and the mechanism of organic molecules is developing from studies aimed at explaining how organic matter, especially those with oxygen-containing functional groups in coal, breaks during pyrolysis. Pyrolytic reactions of 12 organic compounds containin更多还原