煤系针状焦生产中混合油性质与针状焦组织结构研究

In order to enhance the quality of domestic coal-based needle coke and improve and perfect needle coke production technology with independent intellectual property rights, this project extracted bottleneck problems which restrict the quality of needle coke from its industrial production and carry out relevant research works. In the industrial production of needle coke, the material pumped into the coking tower is a kind of mixed oil which consists of a coal tar refined soft pitch and condensate heavy components of high temperature coking oil gas. The fiber-forming ability of aromatic plane macromolecule is directly controlled by the group composition, molecular weight distribution, and average molecular structure of the mixed oil in the liquid phase carbonization process. The mixed oil with different properties was obtained by regulating and controlling the ratio between refined soft pitch and the condensate of high temperature coking oil gas. Starting from the compositions, the structures and the coking properties of mixed oil, the project studied effects of the compositions, the structures and the properties of mixed oil on the quality of needle coke and determined the group composition and the adjustment range of molecular weight distribution of mixed oil. Based on research the liquid phase carbonization coking behavior of mixed oil at normal / pressurized pressure and its pyrolysis kinetics, the project revealed the internal relationship between the microstructure of needle coke and the composition of mixed oil, structure characteristics and liquid phase carbonization characteristics and established the qualitative and quantitative relationship between the performances of mixture oil and the properties of needle coke in the delayed coking process as well as clarified the method which could improve the quality of needle coke. This project could provide theoretical basis and technical supports for improve the quality of domestic coal-based needle coke.

为了提高国产煤系针状焦质量，完善具有自主知识产权的针状焦生产技术，本项目从生产实际中提炼出制约针状焦质量的瓶颈问题，开展相关研究工作。针状焦实际生产过程中进入焦化塔成焦的物料是煤焦油精制软沥青和高温焦化油气冷凝的重组分组成的混合油，混合油的族组成、分子量分布和分子平均结构直接控制着液相炭化过程中芳烃平面大分子的自组装成纤能力。通过调配精制软沥青与高温焦化油气冷凝液的配比，获得性质不同的混合油。从分析混合油的组成、结构和成焦性能入手，研究混合油组成、结构及性质对针状焦质量的影响规律，确定混合油族组成及分子量分布的调控范围；在研究混合油的常压/加压液相炭化成焦行为及热解动力学的基础上，揭示针状焦的显微结构与混合油组成、结构特征及液相炭化特性的内在关系，建立延迟焦化工艺中混合油性质与针状焦性能间的定性、定量关系，阐明提高针状焦质量的方法。为提高我国煤系针状焦质量提供理论依据和关键技术支持。

项目背景及科学意义：针状焦具有低热膨胀系数、高真密度、高电导率、低烧蚀率、低晶胀系数及易石墨化等优点，是生产高功率或超高功率电炉炼钢用石墨电极的优质原料。混合油是精制软沥青及高温油气冷凝的重组分组成的混合物，是生产针状焦过程的中间产物，处在延迟焦化工段的分馏塔塔底部。随着进料时间的增加，混合油的性质发生波动，直接影响针状焦的微观结构。为了提高国产煤系针状焦质量，完善具有自主知识产权的针状焦生产技术，开展混合油性质与针状焦组织结构研究是十分必要的。. 主要完成的研究内容:①完成了精制软沥青的组成（族组成、元素组成）及结构（分子量及其分布、分子平均结构单元）表征，调制出性能适合于制备针状焦的精制软沥青。②完成了精制软沥青与焦化重油不同混合比例对混合油族组成及结构等性质影响的研究。③完成了混合油的热转化炭化行为及动力学参数、高温流变学行为研究，揭示了液相炭化时自组装细纤维组分的显微组织碳的生成机制。④完成了混合油性质及液相炭化工艺条件对针状焦的显微组织及性能指标的影响规律研究，建立它们之间的相关性。. 重要研究成果：提出了通过三元相图法快速制定精制软沥青的制备工艺方案（申请了国家发明专利，已公开）。通过调控延迟焦化中混合油组成及分子量分布，明确了混合油的性质与针状焦显微结构的关系，为生产操作提供理论指导。培养博士研究生3名，硕士研究生8名，本科生18名。发表SCI论文1篇，待刊1篇；EI论文4篇；核心期刊论文7篇；申请发明专利1项。