变径提升管反应器扩径段内气固流动特性研究 |
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引用本文: | 吴文龙,韩超一,李春义,杨朝合. 变径提升管反应器扩径段内气固流动特性研究[J]. 石油炼制与化工, 2014, 45(11): 54-59 |
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作者姓名: | 吴文龙 韩超一 李春义 杨朝合 |
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作者单位: | 中国石油大学(华东)重质油国家重点实验室 |
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基金项目: | 国家重点基础研究发展计划(973)资助项目(2012CB215006) |
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摘 要: | 在变径提升管冷模装置上,以空气和催化裂化平衡剂为介质,考察了颗粒浓度的轴径向分布情况,并对扩径段内的微观流动特性进行了分析。结果表明,变径提升管内颗粒浓度整体上呈“上稀下浓”的分布形式,且沿轴向高度径向不均匀指数逐渐减小。与传统提升管底部相比,扩径段内颗粒浓度及间歇性指数显著增大,且沿径向分布更均匀,说明气固作用力显著增强,并且气固微观流动行为沿径向变化梯度减小。气固微观流动行为受反应器结构影响显著,变径提升管扩径段内气固流动行为类似湍流床,颗粒浓度波动幅度大,频率高,稀相和浓相分布相对均匀,有利于强化气固两相的接触及混合过程。
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关 键 词: | 变径提升管 扩径段 气固微观流动行为 间歇性指数 颗粒浓度 |
收稿时间: | 2014-04-25 |
修稿时间: | 2014-07-02 |
STUDY ON CHARACTERISTICS OF GAS-SOLIDS FLOW IN DIAMETER-ENLARGED SECTION OF A NOVEL RISER REACTOR |
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Abstract: | Axial and radial solid concentration profiles inside a novel riser reactor featured by bottom enlargement were investigated and the characteristics of gas-solid microflow behavior in the diameter-enlarged section were analyzed in a cold model apparatus. The results show that the solid concentration distributions are characterized by two regions: dense bottom region and dilute upper region with a reduced radial non-uniformity index along the axial direction. Compared with the bottom region of the conventional riser, higher solid concentration and intermittency index with more uniform radial distribution in the diameter-enlarged section are observed, demonstrating a stronger gas-solid interaction and a smaller radial gradient of the gas-solid microflow behavior. The gas-solid microflow behavior inside the diameter-enlarged section performs similarly to that in turbulent flow and is significantly affected by the structure of the reactor. The fluctuations of solid concentration in the diameter-enlarged section are characteristic of large amplitude and high frequency, and the distributions of dilute phase and dense phase are relatively uniform, which intensifies the gas-solid contacting and mixing process. |
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