【作者】 李敏；

【导师】 倪明江； 方梦祥；

【作者基本信息】 浙江大学 ， 动力工程（专业学位）， 2015， 硕士

【摘要】 我国富煤缺油少气的能源形势和严重的环境污染现状,要求煤炭进行资源化、能源化以及高效低污染利用。浙江大学开发的煤热解燃烧技术是一种能解决能源短缺和环境污染的高效技术,如若能实现定向热解,提高热解的焦油品质,将极大提高技术的经济价值和环境效益。为此本文开展了煤加氢催化热解的实验研究,期望能够提高煤气、焦油的产率和品质。首先制备了Ni负载量为2%、5%、8%、10%的Ni/Al2O3的催化剂,利用热重红外联用仪(TG-FTIR)及快速裂解与色质联用仪(Py-GC/MS)对陕西延长烟煤进行加氢和催化热解研究,并对催化剂和固体产物进行了扫描电镜(SEM)、比表面积(BET)、X射线衍射(XRD)表征,探讨了升温速率、气氛、催化剂添加量对煤热解特性的影响,同时采用Coats-Redfern法计算了不同工况煤热解时的反应动力学参数。结果表明：煤在CH4气氛下热解时700℃后失重曲线存在一个失重和增重的转折点；混合气氛(H2和CH4)中过多的H2不利于热解时挥发分的析出,但H2对CH4的炭化有抑制作用。根据活化能显示的催化效果：5%Ni>10%Ni>8%Ni>2%Ni。在管式炉上考察了富氢气氛和Ni/Al2O3、Mo/HZSM-5催化剂对煤热解特性的影响。通过对产物的分析结果表明：与N2气氛相比,CH4气氛热解焦油中的重质组分有增加趋势；而H2气氛与混合气氛有助于焦油轻质化和焦油中杂原子的脱除；Ni/Al2O3催化作用下在500-800℃热解焦油中的轻质组分都高达90%；Mo/HZSM-5催化剂使焦油分子更倾向于芳构成苯环等重质组分；煤与催化剂非混合热解时,Mo基芳构化作用减小,焦油中脂肪烃产率增加。随着温度的升高,各组分气体析出提前,最大析出浓度增大。相比于N2气氛,加氢气氛会延迟气体的析出时间；催化剂作用下气体最大析出浓度会提高,但其高浓度析出时间会缩短。更多还原

【Abstract】 In China, the energy situation of rich coal with lack of gas and oil, and the present status of serious environmental issues, give rise to recycling, energy and high efficiency utilization of coal with low pollution. Coal pyrolysis combustion technology developed by Zhejiang University is an effective way to solve the problem of energy shortage and environmental pollution. If coal directional pyrolysis can be realized and tar quality be improved, the higher economic and environmental benefits of the polygeneration technology will be achieved. Therefore, this paper launched researches on hydropyrolysis and catalytic pyrolysis of coal, for a purpose of increasing quality and quantity of tar and gas.First, by preparation of Ni/Al2O3with Ni loading (2%,5%,8%,10%), the effect of hydrogen-rich atmosphere and catalysts on Shaanxi Yanchang coal pyrolysis was investigated through TG-FTIR and Py-GC/MS. With catalysts and solid products analyzed by SEM, BET and XRD, the effects of heating rate, atmosphere and catalyst amount on coal pyrolysis characteristics were discussed. Coats-Redfern method was used to solve the kinetics parameters of coal pyrolysis under different atmospheres. Analysis result shows that, after700℃there is a turning point of weight loss on thermo-gravimetric curve of CH4atmosphere pyrolysis.In mixed gas atmosphere, H2restrains CH4from carbonizing but too much is likely adverse to volatile escaping. According to activation energy, the catalytic effect is order by:5%Ni>10%Ni>8%Ni>2%Ni.Besides, the effects of hydrogen-rich atmosphere, N1/Al;2O3or Mo/HZSM-5catalyst on pyrolysis characters were investigated in a tube furnace. Analysis result shows that, compared with N2atmosphere pyrolysis, the content of heavy components in tar during CH4atmosphere pyrolysis has increasd. H2atmosphere and mixed atmosphere contribute to producing light oil and removal of impurity atoms from tar. With Ni/Al2O3catalyst, the light component content of tar is as high as90%between500℃and800℃. With Mo/HZSM-5catalyst, the tar molecules tend to form heavy components such as benzenes. When the pyrolysis is isolated in relation to coal and catalysts, aromatization effect of Mo is reduced, and yield of aliphatic hydrocarbon in the tar increases. With temperature going up, all component gases release earlier and their largest release concentration improves.Hydrogenation has a delayed effect on the time of gas release, and catalystic process increases the largest release concentration of gases as well as shortens their high release time.更多还原