The hydrocracking process and the combined process of hydrogenation and catalytic cracking (HCC) are the common processes to convert inferior light cycle oil (LCO) into gasoline. In this work, the two processes were investigated and compared systematically. Based on the analysis of product distribution and hydrocarbon composition, it was found that, the higher hydrogen transfer reactivity of hydrogenated LCO in HCC process had an adverse effect on the yield of gasoline. While for the hydrocracking technology, the high conversion of LCO and high quality of gasoline were hardly satisfied simultaneously. In contrast, the mild hydrocracking process not only contributed to the ring-opening reaction of naphtheno-aromatics efficiently, but also yielded a higher content of aromatics in the gasoline product. The as-obtained unreacted light cycle oil (ULCO) from mild hydrocracking could be further treated in the fluid catalytic cracking unit, and the operating conditions for maximum high-quality gasoline production were optimized herein. Ultimately, a novel combined process of mild hydrocracking and catalytic cracking (MHC-FCC) was proposed. In the MHC-FCC process, LCO was primarily hydrocracked mildly, and then the ULCO was separated and subjected to catalytic cracking reaction, achieving a satisfying conversion ~85 wt% and high yield of high-quality gasoline ~65 wt%.

加氢裂化过程以及加氢和催化裂化的组合过程（HCC）是将次轻质循环油（LCO）转化为汽油的常见过程。在这项工作中，对这两个过程进行了系统地调查和比较。通过对产物分布和烃组成的分析，发现在HCC过程中，氢化LCO的较高的氢转移反应性对汽油的收率产生不利影响。对于加氢裂化技术，几乎不能同时满足LCO的高转化率和汽油的高质量。相反，温和的加氢裂化过程不仅有效地促进了环烷芳烃的开环反应，而且在汽油产品中产生了更高含量的芳烃。轻度加氢裂化获得的未反应轻循环油（ULCO）可以在流化催化裂化装置中进行进一步处理，并在此优化了最大质量汽油生产的操作条件。最终，提出了一种轻度加氢裂化和催化裂化的新型组合工艺（MHC-FCC）。在MHC-FCC工艺中，首先对LCO进行轻度加氢裂化，然后将ULCO分离并进行催化裂化反应，获得令人满意的〜85 wt％的转化率和〜65 wt％的高品质汽油。