连续三相喷射环流反应器的实验和数值模拟
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摘要
利用Pavlov管和电导探针分别测量含小颗粒(Stokes数小于1.0)的连续气液固三相喷射环流反应器内轴向液速和气体体积分数分布.提出大气泡-小气泡-浆态相三相流体力学模型,以模拟三相喷射环流反应器的流体力学行为,对大气泡相和小气泡相分别考虑尾涡加速和气泡阻碍效应并修正其曳力.对于上升区和下降区,流场模拟结果均与实验结果较吻合.利用模型预测不同固体体积分数下的气体体积分数与轴向液速分布,结果表明,在考虑的固体体积分数范围内,气体体积分数随固体体积分数增加而下降,液体循环速度随固体体积分数增加而略有上升,其原因主要是反应器内平均气泡直径随固体体积分数增加而增大,进而导致气泡浮升速度加大并增强周围流体的加速运动.
Distribution of axial liquid velocity and gas volume fraction in a sequential gas-liquid-solid three phase jet-loop reactor containing small particles with Stokes number less than 1.0 were measured by Pavlov tube and conductivity probe, respectively. A large bubble-small bubble-slurry three phase fluid dynamic model, incorporating the respective consideration of wake acceleration and bubble hindrance effect for large and small bubble phases in the modified drag forces, was developed to simulate the hydrodynamics in a three phase jet-loop reactor. The numerical results of flow filed in the riser and downcomer were in good agreement with the experimental results.The model was used to predict the axial liquid velocity and gas volume fraction in different solid volume fractions.Results showed that the gas volume fraction decreased while the liquid circulation velocity increased slightly with the increase of solid volume fraction, under the considered solid volume fraction range. The reason is that the average bubble diameter increases when solid volume fraction rises, which increases the bubble rise velocity and enhances the accelerated movement of the surrounding fluid.
Distribution of axial liquid velocity and gas volume fraction in a sequential gas-liquid-solid three phase jet-loop reactor containing small particles with Stokes number less than 1.0 were measured by Pavlov tube and conductivity probe, respectively. A large bubble-small bubble-slurry three phase fluid dynamic model, incorporating the respective consideration of wake acceleration and bubble hindrance effect for large and small bubble phases in the modified drag forces, was developed to simulate the hydrodynamics in a three phase jet-loop reactor. The numerical results of flow filed in the riser and downcomer were in good agreement with the experimental results.The model was used to predict the axial liquid velocity and gas volume fraction in different solid volume fractions.Results showed that the gas volume fraction decreased while the liquid circulation velocity increased slightly with the increase of solid volume fraction, under the considered solid volume fraction range. The reason is that the average bubble diameter increases when solid volume fraction rises, which increases the bubble rise velocity and enhances the accelerated movement of the surrounding fluid.
引文
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[26]BESAGNI G,INZOLI F,ZIEGENHEIN T,et al.Computational fluid-dynamic modeling of the pseudo-homogeneous flow regime in large-scale bubble columns[J].Chemical Engineering Science,2017,160:144-160.
[27]SCHILLER V L.A drag coefficient correlation[J].Zeitschrift des Vereins Deutscher Ingenieure,1933,77:318-320.
[28]WANG T F,WANG J F,JIN Y.A CFD-PBMcoupled model for gas-liquid flows[J].AIChEJournal,2006,52(1):125-140.
[29]ROGHAIR I,ANNALAND M V S,KUIPERS H J AM.Drag force and clustering in bubble swarms[J].AIChE Journal,2013,59(5):1791-1800.
[30]TALVY S,COCKX A,LINE A.Modeling hydrodynamics of gas-liquid airlift reactor[J].AIChE Journal,2007,53(2):335-353.
[31]ANTAL S P,LAHEY R T,FLAHERTY J E.Analysis of phase distribution in fully-developed laminar bubbly 2-phase flow[J].International Journal of Multiphase Flow,1991,17(5):635-652.
[32]SATO Y,SADATOMI M,SEKOGUCHI K.Momentum and heat transfer in two-phase bubble flow:I.theory[J].International Journal of Multiphase Flow,1981,7(2):167-177.
[33]THOMAS D G.Transport characteristics of suspension:VIII.a note on the viscosity of Newtonian suspensions of uniform spherical particles[J].Journal of Colloid Science,1965,20(3):267-277.
[34]KRISHNA R,URSEANU M I,VAN BATEN J M,et al.Rise velocity of a swarm of large gas bubbles in liquids[J].Chemical Engineering Science,1999,54(2):171-183.
[35]REILLY I G,SCOTT D S,DEBRUIJN T,et al.The role of gas-phase momentum in determining gas holdup and hydrodynamic flow regimes in bubblecolumn operations[J].Canadian Journal of Chemical Engineering,1994,72(1):3-12.
[36]KRISHNA R,DESWART J,ELLENBERGER J,et al.Gas holdup in slurry bubble columns:effect of column diameter and slurry concentrations[J].AIChE Journal,1997,43(2):311-316.
[2]杨高东,刘小鹃,吴平铿,等.喷射环流反应器应用研究进展[J].化工进展,2011,30(9):1878-1883.YANG Gao-dong,LIU Xiao-juan,WU Ping-keng,et al.Research progress of application of jet-loopreactor[J].Chemical Industry and Engineering Progress,2011,30(9):1878-1883.
[3]GARCIA-CALVO E,RODRIGUEZ A,PRADOS A,et al.A fluid dynamic model for three-phase airlift reactors[J].Chemical Engineering Science,1999,54(13/14):2359-2370.
[4]JIA X,WEN J,FENG W,et al.Local hydrodynamics modeling of a gas-liquid-solid three-phase airlift loop reactor[J].Industrial and Engineering Chemistry Research,2007,46(15):5210-5220.
[5]SADEGHIZADEH A,RAHIMI R,DAD F F.Computational fluid dynamics modeling of carbon dioxide capture from air using biocatalyst in an airlift reactor[J].Bioresource Technology,2018,253:154-164.
[6]张宝泉,胡宗定.喷射式环流反应器的研究[J].化工学报,1989(6):733-740.ZHANG Bao-quan,HU Zong-ding.Experimental study of jet-loop reactor[J].Journal of Chemical Industry and Engineering(China),1989(6):733-740.
[7]FADAVI A,CHISTI Y.Gas-liquid mass transfer in a novel forced circulation loop reactor[J].Chemical Engineering Journal,2005,112(1-3):73-80.
[8]FADAVI A,CHISTI Y.Gas holdup and mixing characteristics of a novel forced circulation loop reactor[J].Chemical Engineering Journal,2007,131(1-3):105-111.
[9]PADMAVATHI G,RAO K R.Hydrodynamic characteristics of reversed flow jet loop reactor as a gas-liquid solid contactor[J].Chemical Engineering Science,1991,46(12):3293-3296.
[10]VELAN M,RAMANUJAM T K.Gas-liquid masstransfer in a down flow jet loop reactor[J].Chemical Engineering Science,1992,47(9-11):2871-2876.
[11]HEITHOFF S,KüCK U D,VOLKMER P,et al.Modelling gas-liquid mass transfer in a two-phase jet flow[J].Canadian Journal of Chemical Engineering,2018,96(11):2484-2491.
[12]卢浩然,高用祥,成有为,等.喷射型环流反应器中气含率和液速的分布[J].高校化学工程学报,2017,31(5):1088-1095.LU Hao-ran,GAO Yong-xiang,CHENG You-wei,et al.Gas holdup and liquid velocity distribution in a jet loop reactor[J].Journal of Chemical Engineering of Chinese Universities,2017,31(5):1088-1095.
[13]GAO Y X,HONG D,LU H R,et al.Gas holdup and liquid velocity distributions in the up flow jet-loop reactor[J].Chemical Engineering Research and Design,2018,136:94-104.
[14]谭朝尹,孙勤,杨阿三,等.喷射式环流反应器内流速分布的实验研究[J].化学工程,2012,40(8):61-64.TAN Chao-yin,SUN Qin,YANG A-san,et al.Experimental research on velocity distribution within jet loop reactor[J].Chemical Engineering(China),2012,40(8):61-64.
[15]FAN L S,HWANG S J,MATSUURA A.Hydrodynamic behavior of a draft tube gas-liquid solid spouted bed[J].Chemical Engineering Science,1984,39(12):1677-1688.
[16]PIRONTI F F,MEDINA V R,CALVO R,et al.Effect of draft tube position on the hydrodynamics of a draft tube slurry bubble column[J].Chemical Engineering Journal,1995,60(1-3):155-160.
[17]王一平,胡宗定.喷射环流三相流化床反应器轴向液速分布的研究[J].化学反应工程与工艺,1990,6(1):57-62.WANG Yi-ping,HU Zong-ding.Study on the liquid velocity distribution along the axis of a jet loop three-phase fluidized bed reactor[J].Chemical Reaction Engineering and Technology,1990,6(1):57-62.
[18]王方方,杨阿三,孙勤,等.喷射环流反应器内部过滤操作研究[J].高校化学工程学报,2015,29(6):1502-1506.WANG Fang-fang,YANG A-san,SUN Qin,et al.Operating performance of draft tube filtrator within a jet loop reactor[J].Journal of Chemical Engineering of Chinese Universities,2015,29(6):1502-1506.
[19]SZAFRAN R G,KMIEC A.Application of CFDmodelling technique in engineering calculations of three-phase flow hydrodynamics in a jet-loop reactor[J].International Journal of Chemical Reactor Engineering,2004,2(1):A30.
[20]张佳宝,崔丽杰,杨宁.曳力模型和湍流模型对内环流反应器数值模拟的影响[J].化工学报,2018,69(1):389-395.ZHANG Jia-bao,CUI Li-jie,YANG Ning.Effects of drag model and turbulence model on simulation of air-lift internal-loop reactor[J].Journal of Chemical Industry and Engineering(China),2018,69(1):389-395.
[21]KRISHNA R,VAN BATEN J M,URSEANU M I.Three-phase Eulerian simulations of bubble column reactors operating in the churn-turbulent regime:a scale up strategy[J].Chemical Engineering Science,2000,55(16):3275-3286.
[22]HEIJNEN J J,HOLS J,VANDERLANS R,et al.Asimple hydrodynamic model for the liquid circulation velocity in a full-scale two-and threephase internal airlift reactor operating in the gas recirculation regime[J].Chemical Engineering Science,1997,52(15):2527-2540.
[23]HOOSHYAR N,VAN OMMEN J R,HAMERSMA PJ,et al.Dynamics of single rising bubbles in neutrally buoyant liquid-solid suspensions[J].Physical Review Letters,2013,110(24):244501.
[24]MANJREKAR O N,DUDUKOVIC M P.Application of a 4-point optical probe to a slurry bubble column reactor[J].Chemical Engineering Science,2015,131:313-322.
[25]SIEGEL M H,MERCHUK J C,SCHUGERL K.Airlift reactor analysis:interrelationships between riser,downcomer,and gas-liquid separator behavior,including gas recirculation effects[J].AIChEJournal,1986,32(10):1585-1596.
[26]BESAGNI G,INZOLI F,ZIEGENHEIN T,et al.Computational fluid-dynamic modeling of the pseudo-homogeneous flow regime in large-scale bubble columns[J].Chemical Engineering Science,2017,160:144-160.
[27]SCHILLER V L.A drag coefficient correlation[J].Zeitschrift des Vereins Deutscher Ingenieure,1933,77:318-320.
[28]WANG T F,WANG J F,JIN Y.A CFD-PBMcoupled model for gas-liquid flows[J].AIChEJournal,2006,52(1):125-140.
[29]ROGHAIR I,ANNALAND M V S,KUIPERS H J AM.Drag force and clustering in bubble swarms[J].AIChE Journal,2013,59(5):1791-1800.
[30]TALVY S,COCKX A,LINE A.Modeling hydrodynamics of gas-liquid airlift reactor[J].AIChE Journal,2007,53(2):335-353.
[31]ANTAL S P,LAHEY R T,FLAHERTY J E.Analysis of phase distribution in fully-developed laminar bubbly 2-phase flow[J].International Journal of Multiphase Flow,1991,17(5):635-652.
[32]SATO Y,SADATOMI M,SEKOGUCHI K.Momentum and heat transfer in two-phase bubble flow:I.theory[J].International Journal of Multiphase Flow,1981,7(2):167-177.
[33]THOMAS D G.Transport characteristics of suspension:VIII.a note on the viscosity of Newtonian suspensions of uniform spherical particles[J].Journal of Colloid Science,1965,20(3):267-277.
[34]KRISHNA R,URSEANU M I,VAN BATEN J M,et al.Rise velocity of a swarm of large gas bubbles in liquids[J].Chemical Engineering Science,1999,54(2):171-183.
[35]REILLY I G,SCOTT D S,DEBRUIJN T,et al.The role of gas-phase momentum in determining gas holdup and hydrodynamic flow regimes in bubblecolumn operations[J].Canadian Journal of Chemical Engineering,1994,72(1):3-12.
[36]KRISHNA R,DESWART J,ELLENBERGER J,et al.Gas holdup in slurry bubble columns:effect of column diameter and slurry concentrations[J].AIChE Journal,1997,43(2):311-316.