Abstract:

The shifting landscape of China’s fuel market, characterized by a declining diesel-to-gasoline ratio and the rigorous enforcement of China VI diesel standards, has intensified the challenge of optimizing light cycle oil （LCO） utilization. The trend of diesel overcapacity coincides with a growing supply-demand imbalance in key petrochemical building blocks, namely benzene, toluene, and xylene （BTX）. In this context, hydrocracking （HYC） is increasingly recognized as a pivotal upgrading technology to address both issues simultaneously: alleviating the diesel surplus while selectively producing high-value BTX aromatics. This review provides a systematic analysis of contemporary technologies for the catalytic transformation of LCO into BTX. We delve into the fundamental reaction mechanisms, including hydrogenation, ring-opening, and dealkylation, which govern the selectivity towards light aromatics. A particular focus is placed on recent advancements in bifunctional catalyst design, in which the delicate balance between metal function and zeolite acidity is critical for directing the reaction pathway. Furthermore, we critically analyze the often-overlooked aspect of mass transfer and diffusion limitations within catalyst particles and zeolite micropores. A profound understanding of molecular diffusion is paramount for the rational design of next-generation catalysts, ultimately enabling the highly efficient and selective conversion of low-value LCO into premium BTX products via hydrocracking.

Key words: light cycle oil （LCO）, BTX aromatics, catalyst, product selectivity, molecular diffusion