Abstract: In the short-contact, high-temperature processes such as fluid catalytic cracking, the stripping efficiency is a critical factor significantly determining product yield. To improve the stripper performance, a large-scale cold experimental model is employed to investigate the hydrodynamic and mass transfer performance of a novel packing stripping column. In the experiment, air was used to simulate stripping steam. Fiber optic probes and tracer gas methods were employed to measure bubble characteristics, solid content as well as stripping efficiency under various operating conditions. The results indicated that the novel internal component effectively broke up the rising bubbles, reduced bubble size, and increased bubble frequency. Downstream of this component, it was found that the bubble size distribution became more uniform, the bubble frequency increased, and the radial solid retention gradient decreased. It improved gas-solid contact and enhanced fluidization uniformity. Based on analyzing the axial flow behavior, the strippers divided into three functional zones: the nature evolution zone, the forced crushing zone, and the recovery coalescence zone. The forced crushing zone was particularly significant as it suppressed bubble coalescence and enhanced mass transfer. The measured stripping efficiency exhibited a non-monotonic relationship to the superficial gas velocity. Efficiency peaked at 98% when the gas velocity was 0.22 m/s, corresponding to the smallest and the most uniform bubbles distribution, along with optimal gas-liquid contacting. Both excessively low and high gas velocities reduced efficiency due to limited contact or particle entrainment. The novel internal structure significantly improved the two phase flow and mass transfer, achieving a high stripping efficiency and providing practical data in optimizing and designing commercial stripping columns in catalytic processes.

Key words: stripper, internals, gas-solid mass transfer, bubble behavior, stripping efficiency

摘要： 催化裂化等高温短接触工艺汽提段的汽提效率对产物收率至关重要。通过大型冷模实验考察了一种新型内构件汽提器中气固两相流动特性及性能。该内构件能够有效破碎上行气泡，减小气泡尺寸，增加气泡频率。在内构件下游区，相较于上游，气泡尺寸径向分布差异明显减小，气泡频率整体增加且分布改善，固含率径向梯度减弱，从而有效抑制了床层内流动参数的非均匀性。根据流动特性沿轴向将整个汽提器分为自然演化段、强制破碎段、恢复聚并段三个区段。汽提效率随气速呈非单调变化，在气速约0.22 m/s时，汽提效率最高可达98%。

关键词: 汽提段, 内构件, 气固传质, 气泡行为, 汽提效率