【作者】 赵钢炜；

【导师】 那永洁； 朱玉雷；

【作者基本信息】 中国科学院研究生院（工程热物理研究所） ， 工程热物理， 2014， 博士

【摘要】 褐煤提质是低阶煤加工利用的重要途径之一。热解产物中焦油及其中的酚类化合物尤其是低级酚(苯酚、甲基苯酚、二甲基苯酚)的含量相当可观且工业利用价值高。本论文利用电加热固定床反应装置对云南昭通褐煤进行了热解实验,考察了热解反应条件对热解液态产物(焦油及低级酚)产率的影响,在此实验基础上优化了热解反应条件,同时采用与加氢催化实验相结合的热解反应条件提高低级酚产率,对拓宽焦油的非燃料油用途有现实意义。在固定床反应装置上,结合热重分析仪、气相色谱、气质联用仪等分析手段,对云南昭通褐煤的热解及加氢催化热解过程中焦油及酚类化合物分布进行了定向转化的实验研究,考察了固定床热解实验条件对低级酚产率的影响规律,通过实验条件的改进以提高低级酚的产率。首先,通过加氢热解反应提高低级酚产率,基于降低氢耗及提高加氢效率的原则采用分段加氢的反应路径,降低了氢耗的同时提高了低级酚产率；其次,通过改变加料方式和提高升温速率以提高加氢热解中低级酚的产率；最后,结合氢溢流原理及加氢催化裂化工艺,将云南昭通褐煤快速加氢热解与催化反应相结合,采用在线催化的反应路径,改变催化剂的配比、催化方式等条件,焦油产率及焦油中轻质组分(BTX(苯、甲苯、二甲苯)、低级酚(酚、甲基酚、二甲基酚)、低分子萘(萘、甲基萘))的含量均有不同程度的改变。主要研究内容及结果如下：(1)在固定床反应装置上以氮气为载气,考察了热解反应温度200～800℃、停留时间0～30min、载气流量100～400m1/min、升温速率5～30℃/min等反应条件,对云南昭通褐煤热解过程中焦油及酚类化合物产率的影响。实验结果表明：焦油产率在热解反应温度550℃、热解终温停留时间20min、载气流量200ml/min、升温速率为20℃/min的条件下达到最大值；随热解反应温度升高,总酚产率先升后降,在520℃时达到最大值；低级酚产率随热解反应温度的升高而增加；总酚产率随着停留时间的增加而增加,在10min后变化不明显；随着升温速率的提高,低级酚产率和高级酚产率均呈现上升趋势。(2)在选取的热解反应条件下,通入氢气以提高低级酚的产率,为了提高加氢效率,采用350℃后再引入氢气并在450℃时停留10min的分段加氢反应路径,此反应路径较传统加氢热解工艺具有降低氢耗、提高焦油及酚类化合物产率的优点。(3)根据提高升温速率可以提高热解过程中的低级酚产率的规律,在固定床热解反应器中,通过改变加料方式提高升温速率。在快速热解过程中,考察了热解反应温度、载气流量及停留时间等对焦油产率及酚类化合物分布的影响。实验结果表明：随着热解反应温度的升高,焦油产率先升高后降低,在520℃附近达到最大值；总酚产率呈现出与焦油产率相同的反应趋势,并在540℃左右为最大值；较慢速热解反应过程相比,快速热解过程中低级酚的产率明显提高。(4)在快速热解反应条件下,结合氢溢流原理及加氢催化裂化工艺,考察了不同催化剂含量及催化方式(催化剂前置、后置)对加氢催化热解产物中焦油及轻质组分(BTX、低级酚、低分子萘类)含量的影响规律。首先利用热重分析仪对煤样催化热解转化率及反应过程进行了分析研究,选用Ni、Mo为活性中心的催化剂进行加氢催化热解实验。在固定床实验装置上进行了加氢快速热解实验,不同的催化剂浸渍液浓度及催化方式对于焦油中轻质组分具有不同的催化效果：对于低级酚、BTX的产率,后置9#催化剂效果最明显,对于低分子萘则后置3#催化剂效果最佳。采用自制催化剂进行的加氢催化热解反应,对于提高加氢效率、实现催化剂与半焦的分离、回收及再生、定向热解以提高焦油中高价值组分的产率有重要的意义。更多还原

【Abstract】 The upgrading of lignite is one of the important ways of low rank coal utilization. The industrial value of tar and phenolic compounds in the pyrolysis products, especially the low-level phenols (such as phenol, cresol and xylenol) is rather high, and the simple phenols content is considerable. In the dissertation, a series of pyrolysis experiments with Yunnan Zhaotong lignite were conducted in an electricity heated fixed-bed in order to investigate the effect of reaction condition on the yield, composition and distribution of the tar and low-level phenolic compounds. Based on the experiments, the experimental conditions are optimized, and meanwhile the catalyst is used to improve the yield of tar and low-level phenolic compounds. It is realistically significant to broaden the way of coal tar utilization.In the dissertation, directional conversion experiments with the tar and phenolic compounds from lignite and catalytic pyrolysis in the fixed-bed with the thermogravimetric analyzer, gas chromatography and GC-MS analysis were conducted in order to investigate the effect of experiment conditions on the low-level phenolic compounds yield. First, in the fixed-bed pyrolysis, the path of piecewise hydrogenation was proposed to reduce the hydrogen consumption and improve the hydrogenation efficiency. Second, changing the fuel-feeding method and increasing heating rate were adopted to increase the low-level phenolic compounds yield. Finally, in the fast pyrolysis process, combing the hydrogen spillover mechanism and catalytic cracking hydrogenation process, online catalysis was used. Changing the catalyst ratio and catalytic method can affect the contents of tar yield of and the important components (BTX, PCX, simple naphthalene) in different degree.The main research contents and results are as follows.(1) The effect of the reaction conditions with the reaction temperature of200-800℃, carrier gas flow rate of100-400ml/min, residence time of0-30min, heating rate of 5-30℃/min on the yield of tar and phenolic compounds in the lignite pyrolysis process were explored in the fixed-bed taking nitrogen as carrier gas. The tar yield reaches the maximum at the reaction temperature of550℃, residence time of20min, carrier gas flow rate of200ml/min, heating rate of20℃/min. With the increase in the reaction temperature, the total phenolic compounds yield increases first and then decreases, reaching the maximum at the reaction temperature of520℃. The yield of simple phenols increase with the increase in the pyrolysis temperature. The yield of the total phenolic compounds shows the same tendency with that of the tar, reaching the maximum at the residence time of10min. The yields of the simple phenols and the complicated phenolic compounds increase with the increase in the heating rate.(2) The contents of tar and the simple phenolic compounds increase in the process of pyrolysis hydrogenation. In the dissertation, the method of piecewise hydrogenation reaction is applied. Hydrogen was introduced at the reaction temperature of350℃and then stayed for10minutes at the reaction temperature of450℃. The method can reduce the hydrogen consumption and improve the yield of tar and the phenolic compounds.(3) In the fixed-bed, changing the fuel-feeding method and increasing heating rate were adopted to increase the low-level phenolic compounds yield. The effects of the reaction temperature, the carrier gas flow rate and the residence time on the tar and phenolic compounds distribution were explored in the fast pyrolysis reaction. The experimental results reveal that with the increase in the reaction temperature, the tar yield tends to increase first and then decrease, reaching the maximum at the reaction temperature of520℃. The yield of total phenolic compounds has the same variation tendency with that of tar, reaching the maximum at the reaction temperature of540℃. The yield of the simple phenols in the fast pyrolysis is obviously higher than that in the slow pyrolysis.(4) In order to improve hydro-pyrolysis efficiency and enhance the quality of tar, in the fast pyrolysis process, combing the hydrogen spillover mechanism and catalytic cracking hydrogenation process, online catalysis was used to investigate the effects of catalyst contents and catalytic method on the contents of tar and the important components (BTX, low-level of phenols, simple naphthalene). The conversion rate of coal catalytic pyrolysis was investigated by thermogravimetric analyzer, and Ni and Mo are taken as active centers. The experimental results in the fixed-bed demonstrate that the different catalytic impregnation liquid concentration and the placement of the catalysts display different catalytic effects. The effect of post9#catalyst shows the best effect to PCX and BTX, the post3#catalyst improves the simple naphathlene best. The catalytic pyrolysis reaction with self-prepared catalyst is important to improve the hydrogenation efficiently in the catalytic pyrolysis, realize the catalyst separation, recovery and regeneration of coal catalytic pyrolysis, increase the yield of tar components with high value.更多还原