几种单层桨搅拌槽内宏观混合特性的比较
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摘要
为了丰富对向心桨的混合特性的认识,比较了向心桨、Rushton桨、三斜叶桨和穿流桨的单层桨搅拌槽内的宏观混合特性,考察了搅拌转速、桨叶离底高度对搅拌槽混合时间和功率特性的影响。结果表明,四种桨的宏观混合时间均随着搅拌转速的增加而减少,搅拌功率均随转速的增加逐渐增大。当转速相同时,四种桨型中Rushton桨的功率消耗最大,三斜叶桨功率消耗最小,向心桨的功率消耗仅仅比三斜叶桨高。桨叶离底高度的变化对四种桨型的混合时间和功率的影响不尽相同。混合效率的影响因素大小顺序为:搅拌转速>桨型>桨叶离底高度。在考察的四种桨型中,向心桨的混合效率最高。研究成果可为向心桨等新型搅拌桨的工业应用积累实验数据,为其优化设计和放大提供理论依据。
In order to enrich the data of centripetal impeller performance, the macro-mixing characteristics of stirred tanks installed with centripetal impeller, Rushton impeller, three pitched blade impeller and punched blade impeller were systematically studied. The influence of impeller speed, impeller off-bottom clearance, impeller type on mixing time, power and mixing efficiency of the stirred tank was investigated. The results show that the mixing time of the four impellers are all decreased with increasing impeller speed, and the power are all increased. At the same impeller speed, the power of the Rushton impeller is the highest, and the three pitched blade impeller is the lowest. The power of centripetal impeller is only a little higher than that of the three pitched blade impeller.However, the macro-mixing time of the four impellers shows different trends with increasing the impeller off-bottom clearance. The importance of the factor affecting the macro-mixing efficiency is impeller speed >impeller type >impeller off-bottom clearance. Among the four impellers, the overall evaluation of the macro-mixing efficiency ofthe centripetal impeller is the highest. The research results of this paper can accumulate experimental data for the industrial application of new impellers such as centripetal impeller, and provide theoretical basis for its optimization design and scale-up.
In order to enrich the data of centripetal impeller performance, the macro-mixing characteristics of stirred tanks installed with centripetal impeller, Rushton impeller, three pitched blade impeller and punched blade impeller were systematically studied. The influence of impeller speed, impeller off-bottom clearance, impeller type on mixing time, power and mixing efficiency of the stirred tank was investigated. The results show that the mixing time of the four impellers are all decreased with increasing impeller speed, and the power are all increased. At the same impeller speed, the power of the Rushton impeller is the highest, and the three pitched blade impeller is the lowest. The power of centripetal impeller is only a little higher than that of the three pitched blade impeller.However, the macro-mixing time of the four impellers shows different trends with increasing the impeller off-bottom clearance. The importance of the factor affecting the macro-mixing efficiency is impeller speed >impeller type >impeller off-bottom clearance. Among the four impellers, the overall evaluation of the macro-mixing efficiency ofthe centripetal impeller is the highest. The research results of this paper can accumulate experimental data for the industrial application of new impellers such as centripetal impeller, and provide theoretical basis for its optimization design and scale-up.
引文
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[2] Ascanio G. Mixing time in stirred vessels:a review of experimental techniques[J]. Chinese Journal of Chemical Engineering, 2015, 23(7):1065-1076.
[3]张庆华,毛在砂,杨超,等.搅拌反应器中液相混合时间研究进展[J].化工进展, 2008, 27(10):1544-1550.Zhang Q H, Mao Z S, Yang C, et al. Research progress of liquidphase mixing time in stirred tanks[J]. Chemical Industry and Engineering Progress, 2008, 27(10):1544-1550.
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[5] Bouaifi M, Roustan M. Power consumption, mixing time and homogenization energy in dual-impeller agitated gas-liquid reactors[J]. Chemical Engineering&Processing Process Intensification, 2001, 40(2):87-95.
[6] Raghav Rao K S M S, Joshi J B. Liquid phase mixing in mechanically agitated vessels[J]. Chemical Engineering Communications, 1988, 74(1):1-25.
[7] Zhang Q H, Yong Y M, Mao Z S, et al. Experimental determination and numerical simulation of mixing time in a gasliquid stirred tank[J]. Chemical Engineering Science, 2009, 64(12):2926-2933.
[8] Zhang Q H, Yang C, Mao Z S, et al. Large eddy simulation of turbulent flow and mixing time in a gas-liquid stirred tank[J].Industrial&Engineering Chemistry Research, 2012, 51(30):10124-10131.
[9] Houcine I, Plasari E, David R. Effects of the stirred tank.s design on power consumption and mixing time in liquid phase[J].Chemical Engineering&Technology, 2000, 23(7):605-613.
[10] Min J, Gao Z M, Shi L T. CFD simulation of mixing in a stirred tank with multiple hydrofoil impellers[J]. Chinese Journal of Chemical Engineering, 2005, 13(5):583-588.
[11] Min J, Gao Z M. Large eddy simulations of mixing time in a stirred tank[J]. Chinese Journal of Chemical Engineering, 2006, 14(1):1-7.
[12] Bao Y Y, Lu Y, Liang Q Q, et al. Power demand and mixing performance of coaxial mixers in a stirred tank with CMC solution[J]. Chinese Journal of Chemical Engineering, 2015, 23(4):623-632.
[13] Zhang J J, Gao Z M, Cai Y T, et al. Mass transfer in gas-liquid stirred reactor with various triple-impeller combinations[J].Chinese Journal of Chemical Engineering, 2016, 24(6):703-710.
[14]王能勤,梁正祥,张桂昭.穿流式搅拌桨:88219019.9[P]. 1988-11-19.Wang N Q, Liang Z X, Zhang G Z. Punched impeller:88219019.9[P]. 1988-11-19.
[15] Gu D Y, Liu Z H, Li J, et al. Intensification of chaotic mixing in a stirred tank with a punched rigid flexible impeller and a chaotic motor[J]. Chemical Engineering&Processing, 2017, 122:1-9.
[16] Gu D Y, Liu Z H, Xie Z M, et al. Numerical simulation of solidliquid suspension in a stirred tank with a dual punched rigidflexible impeller[J]. Advanced Powder Technology, 2017, 28(10):2723-2734.
[17]杨超,王涛,毛在砂,等.一种产生向心流动的搅拌桨装置:102049208B[P]. 2013-10-16.Yang C, Wang T, Mao Z S, et al. A mixing paddle device that produces centripetal flow:102049208B[P]. 2013-10-16.
[18] Kulkarni A A, Jha N, Singh A, et al. Fractal impeller for stirred tank reactors[J]. Industrial&Engineering Chemistry Research,2011, 50(12):7667-7676.
[19] Mule G M, Lohia R, Kulkarni A A. Effect of number of branches on the performance of fractal impeller in a stirred tank:mixing and hydrodynamics[J]. Chemical Engineering Research&Design,2016, 108:164-175.
[20] Steiros K, Bruce P J K, Buxton O R H, et al. Power consumption and form drag of regular and fractal-shaped turbines in a stirred tank[J]. AIChE Journal, 2017, 63(2):843-854.
[21] Steiros K, Bruce P J K, Buxton O R H, et al. Effect of blade modifications on the torque and flow field of radial impellers in stirred tanks[J]. Physical Review Fluids, 2017, 2(9):094802.
[22] Basbug S, Papadakis G, Vassilicos J C. Reduced power consumption in stirred vessels by means of fractal impellers[J].AIChE Journal, 2018, 64(4):1485-1499.
[23] Liu Z H, Zheng X P, Liu D, et al. Enhancement of liquid-liquid mixing in a mixer-settler by a double rigid-flexible combination impeller[J]. Chemical Engineering&Processing Process Intensification, 2014, 86:69-77.
[24] Liu Z H, He H X, Zhu J, et al. Energy saving and noise reduction of flow mixing performance intensified by rigid-flexible combination impeller[J]. Asia-Pacific Journal of Chemical Engineering, 2015, 10(5):700-708.
[25] Gu D Y, Liu Z H, Xu C L, et al. Solid-liquid mixing performance in a stirred tank with a double punched rigid-flexible impeller coupled with a chaotic motor[J]. Chemical Engineering&Processing Process Intensification, 2017, 118:37-46.
[26] Gu D Y, Liu Z H, Qiu F C, et al. Design of impeller blades for efficient homogeneity of solid-liquid suspension in a stirred tank reactor[J]. Advanced Powder Technology, 2017, 28(10):2514-2523.
[27] Gu D Y, Liu Z H, Qiu F C, et al. CFD simulation of solid suspension in a stirred reactor driven by a dual punched rigidflexible impeller[J]. International Journal of Chemical Reactor Engineering, 2018, 16(5):1-15.
[28] Qiu F C, Liu Z H, Liu R L, et al. Gas-liquid mixing performance,power consumption, and local void fraction distribution in stirred tank reactors with a rigid-flexile impeller[J]. Experimental Thermal&Fluid Science, 2018, 97:351-363.
[29]龚姚腾,曾令挥,肖顺根.不同搅拌桨形式对稀土萃取槽内搅拌效果的影响模拟分析[J].湿法冶金, 2009,(1):49-52.Gong Y T, Zeng L H, Xiao S G. Simulation analysis on stirring effectiveness of different stirring paddle in rare earth extraction tank[J]. Hydrometallurgy of China, 2009,(1):49-52.
[30]逄启寿,徐金,王海辉,等.搅拌桨结构参数对混合效率的影响[J].中国钨业, 2016, 31(4):73-77.Pang Q S, Xu J, Wang H H, et al. Effects of structure parameters of stirring paddle on mixing efficiency[J]. China Tungsten Industry, 2016, 31(4):73-77.
[2] Ascanio G. Mixing time in stirred vessels:a review of experimental techniques[J]. Chinese Journal of Chemical Engineering, 2015, 23(7):1065-1076.
[3]张庆华,毛在砂,杨超,等.搅拌反应器中液相混合时间研究进展[J].化工进展, 2008, 27(10):1544-1550.Zhang Q H, Mao Z S, Yang C, et al. Research progress of liquidphase mixing time in stirred tanks[J]. Chemical Industry and Engineering Progress, 2008, 27(10):1544-1550.
[4]毛在砂,杨超.化学反应器宏观混合研究进展[J].化工学报,2015, 66(8):2795-2804.Mao Z S, Yang C. Perspective to study on macro-mixing in chemical reactors[J]. CIESC Journal, 2015, 66(8):2795-2804.
[5] Bouaifi M, Roustan M. Power consumption, mixing time and homogenization energy in dual-impeller agitated gas-liquid reactors[J]. Chemical Engineering&Processing Process Intensification, 2001, 40(2):87-95.
[6] Raghav Rao K S M S, Joshi J B. Liquid phase mixing in mechanically agitated vessels[J]. Chemical Engineering Communications, 1988, 74(1):1-25.
[7] Zhang Q H, Yong Y M, Mao Z S, et al. Experimental determination and numerical simulation of mixing time in a gasliquid stirred tank[J]. Chemical Engineering Science, 2009, 64(12):2926-2933.
[8] Zhang Q H, Yang C, Mao Z S, et al. Large eddy simulation of turbulent flow and mixing time in a gas-liquid stirred tank[J].Industrial&Engineering Chemistry Research, 2012, 51(30):10124-10131.
[9] Houcine I, Plasari E, David R. Effects of the stirred tank.s design on power consumption and mixing time in liquid phase[J].Chemical Engineering&Technology, 2000, 23(7):605-613.
[10] Min J, Gao Z M, Shi L T. CFD simulation of mixing in a stirred tank with multiple hydrofoil impellers[J]. Chinese Journal of Chemical Engineering, 2005, 13(5):583-588.
[11] Min J, Gao Z M. Large eddy simulations of mixing time in a stirred tank[J]. Chinese Journal of Chemical Engineering, 2006, 14(1):1-7.
[12] Bao Y Y, Lu Y, Liang Q Q, et al. Power demand and mixing performance of coaxial mixers in a stirred tank with CMC solution[J]. Chinese Journal of Chemical Engineering, 2015, 23(4):623-632.
[13] Zhang J J, Gao Z M, Cai Y T, et al. Mass transfer in gas-liquid stirred reactor with various triple-impeller combinations[J].Chinese Journal of Chemical Engineering, 2016, 24(6):703-710.
[14]王能勤,梁正祥,张桂昭.穿流式搅拌桨:88219019.9[P]. 1988-11-19.Wang N Q, Liang Z X, Zhang G Z. Punched impeller:88219019.9[P]. 1988-11-19.
[15] Gu D Y, Liu Z H, Li J, et al. Intensification of chaotic mixing in a stirred tank with a punched rigid flexible impeller and a chaotic motor[J]. Chemical Engineering&Processing, 2017, 122:1-9.
[16] Gu D Y, Liu Z H, Xie Z M, et al. Numerical simulation of solidliquid suspension in a stirred tank with a dual punched rigidflexible impeller[J]. Advanced Powder Technology, 2017, 28(10):2723-2734.
[17]杨超,王涛,毛在砂,等.一种产生向心流动的搅拌桨装置:102049208B[P]. 2013-10-16.Yang C, Wang T, Mao Z S, et al. A mixing paddle device that produces centripetal flow:102049208B[P]. 2013-10-16.
[18] Kulkarni A A, Jha N, Singh A, et al. Fractal impeller for stirred tank reactors[J]. Industrial&Engineering Chemistry Research,2011, 50(12):7667-7676.
[19] Mule G M, Lohia R, Kulkarni A A. Effect of number of branches on the performance of fractal impeller in a stirred tank:mixing and hydrodynamics[J]. Chemical Engineering Research&Design,2016, 108:164-175.
[20] Steiros K, Bruce P J K, Buxton O R H, et al. Power consumption and form drag of regular and fractal-shaped turbines in a stirred tank[J]. AIChE Journal, 2017, 63(2):843-854.
[21] Steiros K, Bruce P J K, Buxton O R H, et al. Effect of blade modifications on the torque and flow field of radial impellers in stirred tanks[J]. Physical Review Fluids, 2017, 2(9):094802.
[22] Basbug S, Papadakis G, Vassilicos J C. Reduced power consumption in stirred vessels by means of fractal impellers[J].AIChE Journal, 2018, 64(4):1485-1499.
[23] Liu Z H, Zheng X P, Liu D, et al. Enhancement of liquid-liquid mixing in a mixer-settler by a double rigid-flexible combination impeller[J]. Chemical Engineering&Processing Process Intensification, 2014, 86:69-77.
[24] Liu Z H, He H X, Zhu J, et al. Energy saving and noise reduction of flow mixing performance intensified by rigid-flexible combination impeller[J]. Asia-Pacific Journal of Chemical Engineering, 2015, 10(5):700-708.
[25] Gu D Y, Liu Z H, Xu C L, et al. Solid-liquid mixing performance in a stirred tank with a double punched rigid-flexible impeller coupled with a chaotic motor[J]. Chemical Engineering&Processing Process Intensification, 2017, 118:37-46.
[26] Gu D Y, Liu Z H, Qiu F C, et al. Design of impeller blades for efficient homogeneity of solid-liquid suspension in a stirred tank reactor[J]. Advanced Powder Technology, 2017, 28(10):2514-2523.
[27] Gu D Y, Liu Z H, Qiu F C, et al. CFD simulation of solid suspension in a stirred reactor driven by a dual punched rigidflexible impeller[J]. International Journal of Chemical Reactor Engineering, 2018, 16(5):1-15.
[28] Qiu F C, Liu Z H, Liu R L, et al. Gas-liquid mixing performance,power consumption, and local void fraction distribution in stirred tank reactors with a rigid-flexile impeller[J]. Experimental Thermal&Fluid Science, 2018, 97:351-363.
[29]龚姚腾,曾令挥,肖顺根.不同搅拌桨形式对稀土萃取槽内搅拌效果的影响模拟分析[J].湿法冶金, 2009,(1):49-52.Gong Y T, Zeng L H, Xiao S G. Simulation analysis on stirring effectiveness of different stirring paddle in rare earth extraction tank[J]. Hydrometallurgy of China, 2009,(1):49-52.
[30]逄启寿,徐金,王海辉,等.搅拌桨结构参数对混合效率的影响[J].中国钨业, 2016, 31(4):73-77.Pang Q S, Xu J, Wang H H, et al. Effects of structure parameters of stirring paddle on mixing efficiency[J]. China Tungsten Industry, 2016, 31(4):73-77.
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