催化裂化柴油萃取脱芳烃技术研究

传统的芳烃抽提工艺，需要使用1.0~3.5 MPa的高温（180~240 ℃）蒸汽，存在能耗高和高温导致溶剂性能加速恶化的弊端。采用常压低温液-液萃取法对催化裂化柴油进行脱除多环芳烃试验，对萃取脱芳烃 (萃取溶剂为环丁砜，A 剂)、芳烃回收（回收溶剂为B剂）、反萃取(反萃取溶剂为C剂)和溶剂再生等操作单元进行操作条件评选，结果表明：在评选出的最佳萃取脱芳烃条件（A剂/催化裂化柴油体积比1.5、萃取温度50 ℃、萃取时间5 min、相分离时间5 min）和芳烃回收条件B剂/（A剂+芳烃）体积比0.2、萃取温度50 ℃、萃取时间4 min、相分离时间3 min]下，混合芳烃产品收率29.29%，混合芳烃质量分数为93.71%；在最佳反萃取条件C剂/（A剂+B剂）体积比0.2、反萃取温度40 ℃、反萃取时间3 min、相分离时间3 min]和78 ℃减压蒸馏条件下，对溶剂进行再生，再生溶剂与新鲜溶剂的萃取效果基本保持不变。最后提出了催化裂化柴油液-液萃取脱芳烃的原则工艺流程。

STUDY ON AROMATICS REMOVAL FROM FCC DIESEL BY EXTRACTION

The traditional aromatics extraction process requires the use of high temperature （180-240 ℃）steam at 1.0-1.3 MPa, which has the disadvantages of high energy consumption and high temperature leading to fast deterioration of solvent performance. In this paper, liquid-liquid extraction method at low temperature under atmospheric pressure was used to remove polycyclic aromatic hydrocarbons from FCC diesel. The operating conditions of extraction dearomatization, aromatics recovery, reverse extraction and solvent regeneration were investigated. The results showed that the optimal parameters for extraction dearomatization process were as follows: the agent A /FCC diesel volume ratio was 1.5, the extraction temperature was 50 ℃, the extraction time was 5 min, and the phase separation time was 5 min, the aromatics recovery conditions: agent B / (agent A + aromatics) volume ratio was 0.2, the extraction temperature was 50 ℃, the extraction time was 4 min and the phase separation time was 3 min. Under the optimal extraction conditions, the yield of mixed aromatics product was 29.29%, the mass fraction of mixed aromatic was 93.71%. The solvent was regenerated under the best reverse extraction conditions: agent C / (agent A + agent B) volume ratio was 0.2, reverse extraction 40 ℃ and 3 min, the phase separation time was 3 min, and vacuum distillation at 78℃. The extraction effect of the regenerated solvent was as good as the fresh one. Finally, the principle process of liquid-liquid extraction dearomatization for FCC diesel was proposed.