Abstract: For the purpose of increasing yields ratio of diesel and gasoline，the most refinery and petrochemicals often take measures of decreasing ASTM D86 end point of gasoline product of main fractionators in RFCC unit in China, in which serious problems of poor stability and pressure drop rising were encountered in operation of main fractionators equipped with the jet tray. Based on the observations of operation phenomena and test on perform contact tray tested by FRI, a reliable analogy for that on jet trays in industrial tower was made. The results demonstrate that the serious inlet weeping and inlet jetting phenomena take place on the jet tray of main fractionators, showing the significant scale-up effect in largedistillation tower. The key to solve this problem is to control the distribution of liquid layer on the tray. In this paper, the program installing the inlet and outlet weirs on the tray was proposed to regulate the liquid layer and eliminate the scale-up effect, thus lowering the tray pressure drop and improving the operating effects. The results showed that under the conditions of processing capacity of 140 million tons per year, the tower pressure drop from original 28—34 kPa (design experiential values in China) reduced to a stable 16 kPa that is agree with design predicted value 18 kPa, reducing 50%; the total yield of gasoline and diesel increased from 68.13% to 68.48%, the yield of light oil increased 0.35%, the diesel-gasoline ratio increased from 0.82 to 0.88, the gasoline and diesel products from the overlaping 28℃ before the technological revamping reduce to overlaping 6℃, which demonstrated that the separation efficiency was improved. Under the condition of processing capacity of 160 million tons per year, the tower pressure drop rose only to 26 kPa, still lower than that before revamping, and achieved to the smooth operation and qualified product.

Key words: main fractionators in RFCC units, jet tray, perform contact tray, scale up effect, inlet weeping

摘要： 针对工业催化裂化φ5 m的主分馏塔操作稳定性差、压降高等生产问题，利用FRI对网孔塔板试验现象观察结果，对催化分馏塔内固舌塔板的操作现象进行了类比，结果表明：催化分馏塔内的固舌塔板存在着严重的入口泄漏和出口喷射的分相流操作现象，表现出显著放大效应的特征。解决这一问题的关键是调控塔板上液层分布，为此提出了塔板上增设入口堰和出口堰，调控塔板上液层分布，消除放大效应，从而达到降低塔板压降，改善操作效果的目的。通过固舌塔板增堰的新方法并结合部分应用Super V1浮阀塔板，对装置进行了技术改造，结果表明：在140万吨/年加工能力的条件下，改造后的全塔压降由开车初期的28～34 kPa（国内设计经验值）降低到稳定的16 kPa，降低了约50％，该数值与设计计算的全塔压降18 kPa十分一致；汽柴油总收率由原来的68.13％提高到68.48％，轻收提高了0.35%，柴汽比由0.82提高到0.88；汽柴油产品由改造前重叠28℃降低到6℃，表明分离效率得到提高。在160万吨/年加工能力下，全塔压降仅为26 kPa，仍低于扩能前的压降，且操作平稳，产品质量完全合格。

关键词: 催化裂化主分馏塔；固舌塔板；网孔塔板；放大效应, 入口泄漏