煤油共液化残渣制备中间相沥青及其性能研究

发布时间：2018-04-02 11:08

本文选题：共液化残渣　切入点：沥青质　出处：《太原理工大学》2015年硕士论文

【摘要】：煤与油浆共液化处理，可以增加轻质油产量和降低循环溶剂用量，缓解我国石油资源短缺的现状。煤油共液化残渣是一种含碳量较高的副产物，主要用于气化、燃烧、焦化、热解和液化等方面，近年来煤炭产业趋向集约化发展，人们开始用残渣来制备碳素材料。目前用于制备碳素材料的原料主要有价格昂贵的纯芳烃（如萘沥青等），还有组成变化较大的煤焦油沥青、石油沥青以及它们不同比例的混合料，相比之下，，用价格低廉、组成均匀的煤油共液化残渣来制备碳素材料对资源的高效利用和环境保护具有重要意义。本文以不同工艺下兖州煤和石家庄催化裂化甩出油浆共液化残渣为原料，通过热聚合法制备中间相沥青。考察了共液化工艺对残渣组成分布的影响；课题进一步通过残渣中沥青质（HI）的热重分析（TG）和热台实验探讨了残渣制备碳素材料的可能性，利用偏光显微镜和傅里叶红外光谱分析仪（FT-IR）考察了热聚合温度、时间、添加剂、升温速率等对聚合产物中间相沥青性质的影响；本文最后对中间相沥青进行碳化，通过扫描电子显微镜（SEM）和X射线衍射仪（XRD）等手段分析了碳化中间相沥青的结构和微观形貌，测试了碳化中间相的电化学性能。主要得出以下结论：（1）煤油共液化残渣中含有约30%-40%的沥青质（HI）、50%左右的重油（HS）和2%-10%的四氢呋喃不溶物（THFIS）。加氢液化使得残渣中沥青质含量增加，重油和THFIS含量减少，同时重质产物分子量减少；加氢促进了煤的热解反应，生成的沥青质聚合程度较高，相反氮气下得到的沥青质聚合程度较低，含有较多的烷基侧链和环烷结构。（2）沥青质类物质生成中间相沥青的热聚合温度宜选在350℃-500℃之间，其分子量大小要适宜，一般范围为500-600。随着热聚合温度的升高或聚合时间的延长，甲苯不溶物和喹啉不溶物的含量随之增加，中间相沥青从微球形态融并为流线型结构再转化为焦炭，沥青质HI1（H2下共液化所得）在440℃反应6h就可生成广域流线型中间相，有可能用于制备碳纤维或针状焦，沥青质HI2（N2下共液化所得）在440℃反应12h就可生成体型中间相，HI1和HI2在380℃反应10h均可生成大量中间相微球。（3）添加剂聚丙烯（PP）增加了HI1多核芳烃的烷基侧链，降低了体系粘度，促进了球晶的形成和长大，而且随着PP添加量的增多促进作用更明显，而PP与HI2作用时部分烷基与其作用，部分自组装成环烷烃或芳烃，促进微晶形核；添加剂炭黑在中间相形成初期促进形核，后期阻碍微球融并成体中间相。（4）升温速率太慢，不利于中间相的形成；升温速率太快，挥发分逸出较快，粘度迅速变化，不利于光学各向异性组织的有序排列。因此只有在适宜的升温速率下粘度变化适中，才能生成有序的各向异性中间相。（5）由碳化后的中间相微球形貌可知其成核机理为“颗粒基本单元构筑”，为均相形核，结构是“Brooks-Taylor”型结构；碳化后的针状焦结晶度高，择优取向好。上述碳化中间相沥青都有很好的循环伏安特性。
[Abstract]:Coal oil co - liquefaction residue is a byproduct of high carbon content , mainly used for gasification , combustion , coking , pyrolysis and liquefaction .

The effects of co - liquefaction process on the composition distribution of residues were investigated in this paper by using the catalytic cracking of Yanzhou coal and Shijiazhuang in different processes as raw materials , and preparing intermediate phase pitch by thermal polymerization .
In this paper , the possibility of preparing the carbonaceous material from the residue was investigated by TG and FT - IR , and the effects of thermal polymerization temperature , time , additive and temperature rise rate on the properties of the intermediate phase asphalt were investigated by means of polarization microscope and Fourier transform infrared spectrum analyzer ( FT - IR ) .
In this paper , the structure and microstructure of the intermediate phase asphalt were analyzed by scanning electron microscopy ( SEM ) and X - ray diffraction ( XRD ) . The electrochemical properties of the carbonized intermediate phase were tested . The results were as follows :

( 1 ) the coal oil co - liquefaction residue contains about 30 % -40 % of asphalt ( HI ) , 50 % of heavy oil ( HS ) and 2 % -10 % tetrahydrofuran insoluble matter ( THFIS ) . The hydrogenation liquefaction causes the content of asphaltene in the residue to increase , the heavy oil and THFIS content are reduced , and the molecular weight of the heavy product is reduced ;
the hydrogenation promotes the pyrolysis reaction of the coal , the generated pitch polymerization degree is high , and the degree of polymerization of the asphaltene obtained under the opposite nitrogen gas is lower , and contains more alkyl side chains and naphthene structures .

( 2 ) The thermal polymerization temperature of the asphaltene - producing intermediate phase asphalt is preferably between 350 and 500 DEG C . The molecular weight of the intermediate phase asphalt is preferably 500 - 600 . As the temperature of the thermal polymerization increases or the polymerization time is prolonged , the content of the toluene insoluble substance and the quinoline insoluble substance is increased , and the intermediate phase asphalt can be formed into a wide - area streamline intermediate phase at 440 DEG C for 6 hours , and a large amount of intermediate phase microspheres can be generated at the reaction time of HI1 and HI2 at 380 DEG C for 10h .

( 3 ) The additive polypropylene ( PP ) increased the alkyl side chain of HI1 , decreased the system viscosity , promoted the formation and growth of spherulites and promoted the formation and growth of spherulites .
The additive carbon black promotes nucleation at the initial stage of the intermediate phase , and the latter blocks the microspheres to melt and form an intermediate phase .

( 4 ) the heating rate is too slow to be beneficial to the formation of the intermediate phase ;
In order to produce an ordered anisotropic intermediate phase , the temperature rise rate is too fast , the volatile component escapes quickly and the viscosity changes rapidly , which is not good for the ordered arrangement of the optically anisotropic tissue .

( 5 ) It is known that the nucleation mechanism is " particle basic unit construction " , and the structure is " Brooks - Taylor " type structure .
The carbonized intermediate phase asphalt has good cyclic voltammogram characteristics .

【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ529;TQ127.11

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