Abstract:

Benzene, toluene and xylene (BTX), as important basic chemical raw materials, are mainly obtained from petroleum-based process, such as catalytic reforming and steam cracking. However, with the increasing consumption of petroleum resources, it becomes imperative to develop new BTX production technology. Some BTX production technologies reported so far include methanol to aromatics, syngas to aromatics, CO₂ hydrogenation to aromatics and aromatization of light alkanes. Among them, the aromatization of light alkanes has attracted widespread attention due to the sufficient raw materials and low-cost process. Among many aromatization catalysts, the gallium modified HZSM-5 catalysts exhibit excellent dehydrogenation-aromatization performance and are the research hotspot in this field. This paper mainly reviewed the research progress of gallium modified HZSM-5 catalysts in the aromatization of light alkanes from the aspects of the reaction mechanism, the regulation of catalyst properties, and the operating conditions. It was summarized that the state and distribution of Ga species can be controlled by the gallium introduction way, atmosphere pretreatment and calcination temperature. Regulating the acid properties and pore structure of HZSM-5 can improve the activity and stability of catalysts. The introduction of additives such as Pd, Ag, Ni, Pt and Cr can enhance the dehydrogenation activity and improve the aromatization ability. The synergistic effect between B acid sites and L acid sites (active Ga species) in gallium modified HZSM-5 catalysts is helpful to improve the light alkanes aromatization performance. Finally, this paper pointed out that the development of multi-functional synergistic gallium modified HZSM-5 catalysts in the processes of light alkane aromatization and CO₂co-feeding is the key to increasing BTX production and reducing CO₂ emissions.

Key words: alkane, catalyst, stability, aromatization, gallium modification

摘要：

苯、甲苯和二甲苯（BTX）作为重要的基础化工原料，主要来源于催化重整和蒸汽裂解的石油基工艺路线。随着石油资源的日益消耗，开发新的BTX生产工艺势在必行。目前报道的其他BTX生产工艺有甲醇制芳烃、合成气制芳烃、二氧化碳加氢合成芳烃和低碳烷烃的芳构化。其中，低碳烷烃芳构化工艺因其原料来源丰富、工艺过程成本低而引起人们的广泛关注。在众多芳构化催化剂中，镓改性HZSM-5催化剂具有最优异的脱氢-芳构化性能，是本领域的研究热点。基于此，本文主要从低碳烷烃芳构化反应机理、镓改性的HZSM-5性质调控、低碳烷烃芳构化反应操作条件等方面综述了镓改性HZSM-5催化剂在低碳烷烃芳构化中研究进展。总结发现，镓的引入方式、气氛预处理、煅烧温度可以调控Ga物种的状态和分布；调控HZSM-5的酸性质和孔道结构可以提高催化活性和稳定性；引入助剂如Pd、Ag、Ni、Pt、Cr可增强脱氢活性进而提高芳构化性能；镓改性HZSM-5催化剂中B酸位和L酸位（活性Ga物种）之间的协同效应有助于提高低碳烷烃芳构化反应性能。最后，本文指出发展低碳烷烃芳构化与CO₂共转化过程中多功能协同镓改性HZSM-5催化剂是实现BTX产量提升与CO₂减排的关键。

关键词: 烷烃, 催化剂, 稳定性, 芳构化, 镓改性