预提升对循环流化床反应器中气固流动特性的影响

发布时间：2018-06-07 13:29

本文选题：循环流化床 + 预提升　；参考：《石油炼制与化工》2017年02期

【摘要】：以催化裂化平衡剂为固体介质、常温空气作为流化气体,在循环流化床冷态模拟试验装置上分别考察了表观气速、颗粒贮量、下料蝶阀开度、预提升气量等操作条件对循环流化床反应器催化剂循环速率的影响,并探讨了产生这种影响的原因;同时,深入研究了预提升出口位置对系统内催化剂循环速率、提升管底部轴向、径向颗粒浓度分布的影响,并描述了气固两相交汇点处的微观流动结构。结果表明:随着操作气速的升高,气、固相之间的相互作用增强,颗粒循环速率提高;伴床及蝶阀通过提供足够的压力支持提升管内的两相流动,增加颗粒贮量或减小蝶阀压降可有效提高颗粒循环量;通入预提升气可增大颗粒向前运动的推动力,避免颗粒发生坍落而沉积于床层底部;当伴床向提升管提供足够的颗粒循环速率时,预提升出口位置的提高破坏了颗粒的向下流动,迫使颗粒进入中心快速向上的气固流动区,从而改变气、固相交汇点处的流动结构;另外,不同预提升结构对颗粒浓度的影响有限,并未从根本上改变轴向、径向颗粒浓度的分布规律。
[Abstract]:Using FCC equilibrium agent as solid medium and room temperature air as fluidized gas, the apparent gas velocity, particle storage and the opening of feed butterfly valve were investigated in a circulating fluidized bed cold state simulation test device. The effect of operation conditions such as pre-lift gas volume on catalyst circulation rate in circulating fluidized bed reactor is discussed, and the reasons for this effect are discussed, at the same time, the effect of pre-lift outlet position on catalyst circulation rate in the system is deeply studied. The influence of axial and radial particle concentration distribution on the bottom of the riser is discussed. The microstructure of the gas-solid two-phase junction is described. The results show that with the increase of the operating gas velocity, the interaction between the gas and the solid phase increases, the particle circulation rate increases, and the wake bed and butterfly valve support the two-phase flow in the riser by providing sufficient pressure. Increasing particle storage or decreasing butterfly valve pressure drop can effectively increase particle circulation, increase the propelling force of particle forward motion and prevent particles from collapsing and deposit at the bottom of bed. When the wake bed provides a sufficient particle circulation rate to the riser, the increase of the pre-lift exit position destroys the downward flow of the particle, forcing the particle to enter the gas-solid flow zone of the center rapidly upward, thus changing the gas. In addition, the effect of different pre-lifting structures on particle concentration is limited, and the distribution of axial and radial particle concentration has not been fundamentally changed.
【作者单位】：中国石油大学(华东)重质油国家重点实验室;
【分类号】：TE96

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