Abstract: As one of the core equipment of the catalytic cracking unit of the refinery, the regenerator not only ensures catalyst reutilization but also maintains pressure and heat balance within the reaction-regeneration system. However, the main air distribution at the bottom of the regenerator will give rise to particle agglomeration, flow dead zone and other gas-solid mixed flow problems within the regenerator, which will directly affect the thermal balance and continuous and stable operation of the production unit. In this work, computational fluid dynamics (CFD) method is used to simulate and calculate the bottom area of a 0.5 Mt/a catalytic cracking accumulator. Based on the k-ω turbulence model, the gas phase flow state at the bottom of the existing industrial regenerator can be obtained, which will provide some guidance for the gas-solid distribution in the upper and middle regions. Through simulation calculations, it is shown that the radial distribution of gas phase velocity near the outlet of gas distribution is severely uneven. Based on the existing structure and operating conditions of the bottom of the industrial regenerator, improvements are made to improve the uneven radial distribution of gas velocity. The effects of different inlet velocities, inverted cone structures, and distribution plate aperture sizes on the uniformity of gas velocity distribution are studied. The results indicate that the main air flow rate has a significant impact on the radial uniformity of gas velocity. The height to diameter ratio of the inverted cone and the distance from the inverted cone to the gas distributor have little effect on the uniformity of the radial distribution of gas velocity. By increasing the aperture of the limited flow holes in the main air distributor, the uniformity of the radial distribution of gas phase velocity in the area above the distributor is improved, and for this regenerator device, the gas distributor aperture size of around 18 mm is the most suitable.

Key words: Catalytic cracking, Regenerator, Gas distributor, Inverted cone, Flow field

摘要： 为了提升催化裂化再生器底部主风速度径向分布的均匀性，改善再生器中部及以上区段的气固混合状态，采用计算流体力学(CFD)的方法对某50万吨/年催化裂化再生器底部进行了单相流模拟，获得了再生器底部的主风流动状态。结果表明，现有工业再生器底部气体分布器上方区域气相速度径向分布严重不均。在此基础上，研究了不同进风速度、倒锥结构和分布板孔径对气相速度分布均匀性的影响。发现改变主风入口处倒锥的高径比和倒锥距气体分布器的竖直距离对气体分布器出口气体速度径向分布均匀性无明显影响；增大主风分布器的限流孔孔径，分布器上方区域气相速度径向分布的均匀性得到改善，且孔径为18 mm时，主风气体分布效果良好。

关键词: 催化裂化, 再生器, 气体分布器, 倒锥, 流场