Gas-Liquid Dispersion with Buoyant Particles in a Hot-Sparged Stirred Tank

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• 作者：Yuyun Bao ; Zhengming Gao ; Xiaohua Huang ; Litian Shi ; John M. Smith ; Rex B. Thorpe
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2007
• 出版时间：September 26, 2007
• 年：2007
• 卷：46
• 期：20
• 页码：6605 - 6611
• 全文大小：182K
• 年卷期：v.46,no.20(September 26, 2007)
• ISSN：1520-5045

文摘

Many industries use gas-liquid stirred-tank reactors with a third phase of buoyant particles. Few studieshave looked at the effects of buoyant particle characteristics on solid-liquid suspension and gas-liquiddispersion, and even less have considered operation at elevated temperatures. This paper reports powerconsumption and gas holdup measurements made in a hot-sparged three-phase system. The vessel was adished-base reactor of diameter 0.476 m (T) holding 0.145 m³ of liquid, agitated by a multi-impeller agitator(a hollow half-elliptical blade dispersing turbine below two up-pumping wide-blade hydrofoils, identified asHEDT+2WH_U). This configuration has been recommended in previous work. Air, deionized water, andpolypropylene (PP) particles were used in this work. The temperature of the water was in the range 80.5-82.5 C. The results show that, as in a cold system, the effect of the solid concentration on aerated agitatorpower demand is negligible. There is little difference between the agitator power demand in cold- and hot-sparged systems, except that the relative (gassed-to-ungassed ratio) power demand, RPD, is a little higher inhot-sparged conditions. The influence of power consumption and gas rate on gas holdup is slightly less whenhot than when cold. Gas holdup in the hot-sparged system, which, with similar total gas rates and powerinput, is only about one-half or two-thirds of that at room temperature, is slightly increased at higher solidsconcentrations. The reasons for the differences in gas dispersion between cold- and hot-sparged systems areanalyzed and discussed in this paper, with further experimental and CFD studies planned for future work.