To meet the needs of industrial installations to enhance mixing and mass transfer, solving the problem that the liquid turbulence caused by the microbubbles is weak and unfavorable for gas–liquid–solid phases mixing, we propose a concept of employing bubbles with a “bimodal” size distribution. Specifically, microbubbles are introduced to enhance mass transfer, while macrobubbles are utilized to promote mixing. Building upon this design philosophy, we developed a comprehensive gas distributor comprising a swirl-venturi microbubble generator and a ring-shaped gas distributor. This combined system aims to optimize the distribution of the bubble sizes. Experimental studies have been conducted to investigate the impact of bubble size distribution on gas holdup, solid holdup, liquid phase mixing, and the liquid volumetric mass transfer coefficient within the slurry reactor. From the experimental findings, we derive essential principles for the design of the “bimodal” bubble size distribution. First, the superficial gas velocity of the macro bubble should exceed the critical value, set at u_g,trans-tM, which equals 0.077 m/s in our experiments. Second, the proportion of air intake from the swirling-venturi microbubble generator to the total air intake should not surpass the critical ratio α_SVMG,trans established at 30% in this experiment. These principles provide a solid foundation for optimizing the proposed “bimodal” bubble size distribution and improving the overall performance of the slurry reactor.

中文翻译：

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气泡尺寸“双峰”分布增强浆料鼓泡塔反应器中的混合和传质

为了满足工业装置加强混合和传质的需要，解决微气泡引起的液体湍流较弱，不利于气液固相混合的问题，我们提出了“双峰”气泡的概念尺寸分布。具体来说，引入微泡以增强传质，而大泡则用于促进混合。基于这一设计理念，我们开发了一种综合气体分配器，包括旋流文丘里微泡发生器和环形气体分配器。该组合系统旨在优化气泡尺寸的分布。进行了实验研究，以研究气泡尺寸分布对浆态反应器内的气体含率、固持率、液相混合和液体体积传质系数的影响。从实验结果中，我们得出了“双峰”气泡尺寸分布设计的基本原则。首先，大气泡的表观气体速度应超过设定为u _{g,trans-tM 的}临界值，在我们的实验中等于 0.077 m/s。其次，旋流文丘里微泡发生器的进气量占总进气量的比例不应超过本实验中设定的临界比率α _SVMG,trans 30%。这些原理为优化所提出的“双峰”气泡尺寸分布和提高浆态反应器的整体性能提供了坚实的基础。