The combined hydrogenation and catalytic cracking (HCC) process is reported to be able to convert inferior light cycle oil (LCO) into high-quality gasoline efficiently. However, when the LCO rich in tricyclic aromatic hydrocarbons (TAHs) is used as feedstock, a high hydrogenation severity is required to saturate the aromatic rings and abundant gaseous hydrocarbons are generated during the following catalytic cracking process, thereby reducing the gasoline yield and its quality. In this work, the LCO was distilled into light, middle, and heavy fractions, which were rich in mononuclear aromatic hydrocarbons (MAHs), bicyclic aromatic hydrocarbons (BAHs), and TAHs, respectively. Based on the systematic analysis of compositions of hydrogenated LCO fractions and their catalytic cracking products, the optimal hydrogenation severities for each fraction to achieve the maximum gasoline production were determined. A novel combined process of selective hydrogenation and catalytic cracking based on pre-distillation (SHCC-PD) was further proposed. In the SHCC-PD process, LCO was primarily distilled and selectively hydrogenated, thereby delivering an improved catalytic cracking performance with an LCO conversion of ∼66 wt % and selectivity of high-quality gasoline of ∼72 wt %.

中文翻译：

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加氢和催化裂化相结合的轻循环油高效转化为汽油：预蒸馏的效果

据报道，加氢和催化裂化（HCC）组合工艺能够将劣质轻循环油（LCO）有效地转化为优质汽油。但是，当使用富含三环芳烃（TAH）的LCO作为原料时，需要很高的加氢强度以饱和芳环，并且在随后的催化裂化过程中会生成大量气态烃，从而降低了汽油的收率及其质量。在这项工作中，LCO被蒸馏成轻，中和重质馏分，分别富含单核芳香烃（MAH），双环芳香烃（BAH）和TAH。基于对氢化LCO馏分及其催化裂化产物组成的系统分析，确定了每个馏分的最佳氢化强度，以实现最大的汽油产量。进一步提出了一种基于预蒸馏的选择性加氢和催化裂化的新工艺（SHCC-PD）。在SHCC-PD工艺中，首先蒸馏LCO并对其进行选择性氢化，从而提供了改进的催化裂化性能，LCO转化率为〜66 wt％，高品质汽油的选择性为〜72 wt％。