煤直接液化制油技术研究现状及展望

煤直接液化制油技术是促进煤炭清洁高效利用、缓解石油供需矛盾、保障我国能源安全的重要途径。为全面了解煤液化反应机理、动力学、催化剂及工艺的全过程,促进煤直接液化技术基础研究的快速进步和新工艺的开发,笔者综述了国内外在煤加氢液化反应机理、反应动力学、催化剂以及液化工艺方面取得的研究成果,重点介绍了德国IGOR、日本NEDOL和我国的神华煤液化工艺,分析了这些典型煤液化工艺的开发历程和特点;指明了煤直接液化制油技术发展趋势。煤的加氢液化反应是自由基反应机理,是一系列顺序反应和平行反应的综合结果,包含煤的热解、自由基加氢、脱杂原子和缩合反应等,总体上以顺序反应为主。借助同位素示踪、原位实时检测、等离子体技术以及微波快速加热技术等现代分析方法和试验手段,重点研究自由基的产生速率、活性氢产生速率及定量传递机理,有助于深入认识和精准阐明煤加氢液化反应机理。各国学者利用不同的研究方法,针对不同煤种、催化剂、工艺条件和供氢溶剂等,建立了各种各样的动力学模型。动力学模型从单组分到双组分和多组分,从连续反应、平行反应到复杂的网络反应,从最初的一步反应到后来较为合理的多段反应,模型越来越复杂,越来越接近工业应用。根据反应阶段不同进行分段处理的多组分"集总"反应动力学模型将是今后煤加氢液化反应动力学发展的主要方向。借助先进分析手段及科学的处理方法,建立真正揭示不同条件下煤液化动力学规律的通用型动力学模型是未来的发展趋势。借助纳米合成、等离子体等高新技术,调控组分配伍、降低催化剂粒径、优化制备方法是制备高活性催化剂的有效手段。强化系统合理配置和优化集成,重视煤的温和液化和分级转化,优化产品结构,发展直接液化-间接液化耦合技术是煤直接液化未来的发展趋势。

Research progress and prospect of direct liquefaction technology from coal to oil

Direct coal liquefaction technology is an important way to promote the clean and efficient utilization of coal,alleviate the contradiction between oil supply and demand,and ensure the energy security in China.In order to fully understand the whole process of coal liquefaction reaction mechanism,kinetics,catalyst and technology,and promote the rapid progress of basic research of coal direct liquefaction technology and the development of new technology,the research results of the mechanism,reaction kinetics,catalyst and liquefaction process of the hydrogenation liquefaction were introduced. In this paper,the coal liquefaction processes of German IGOR,Japan NEDOL and Shenhua in China were mainly introduced,and the development history and characteristics of these typical coal liquefaction processes were analyzed.The development trend of direct coal liquefaction to oil technology were pointed out.The hydrogenation liquefaction reaction of the coal is a free radical reaction mechanism,which is a comprehensive result of a series of sequential reactions and parallel reactions,and includes pyrolysis of coal,hydrogenation of free radicals,removal of impurity atoms and condensation reaction,etc.In general,the sequential reaction is dominant.With the help of modern analytical methods and experimental methods such as isotope tracing,in situ detection,plasma and microwave rapid heating,the research on the production rate of free radicals,the active hydrogen production rate and the quantitative transfer mechanism of free radical is helpful to further understand and accurately elucidate the mechanism of coal hydrogenation and liquefaction.Using different research methods,the various kinetic models for different coal types,catalysts,process conditions and hydrogen supply solvents have been established in various countries. The kinetic models range from single-component to two-component and multi-component,from continuous reaction,parallel reaction to complex network reaction,from the initial one-step reaction to the later more reasonable multi-stage reaction. The models are becoming more and more complex and closer to industrial applications. The multi-component " lumped" reaction kinetic model based on the different stages of the reaction will be the main direction for the development of coal hydrolique reaction kinetics in the future.By means of the advanced analysis means and the treatment method,it is the development trend in the future to establish the model of the coal liquefaction dynamics law under different conditions.With the help of hightech such as nano-synthesis and plasma,it is an effective method for the preparation of highly active catalysts by controlling the compatibility of components,reducing the particle size of catalyst and optimizing the preparation method. The future development trend of direct coal liquefaction is to strengthen the rational configuration and optimization integration of the system,pay attention to the mild liquefaction and classification transformation of coal,optimize the product structure,and develop the coupling technology of direct and indirect liquefaction.