稀土氯化物喷雾热解装置雾化效果的物理模拟
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摘要
稀土氯化物雾化热解是稀土氧化物制备新工艺,但目前喷雾热解装备雾化效果差,雾化后液滴粒径分布不均匀.本文自行设计了文丘里管喷雾热解反应器,将粒子图像测速技术与MATLAB图像处理技术相结合,研究了气体流量、文丘里管和引流管几何尺寸等因素对雾化效果的影响.结果表明:文丘里管扩散段中较强的回流作用会加剧气液相间的混合碰撞,进一步破碎液滴;而过多的液相携带量容易导致雾滴密度变大,增大了液滴在运动过程中的碰撞几率,致使雾滴尺寸变大.文丘里管反应器适宜的几何尺寸和操作条件为:内径100 mm,喉口内径10 mm,引流管内径5 mm,气相流量20.5 m3/h.
Spray pyrolysis rare-earth chloride is a new process to produce rare-earth oxides,but there are some shortages at present such as the poor atomization effect of spray pyrolysis equipment and the non-uniform distribution of the droplet size after atomization.A Venturi tube spray pyrolysis reactor was designed and particle image velocimetry technology combined with MATLAB image processing technology was used to analyze the effects of gas flow rate,the size of Venturi tube and drainage tube on the atomization.The results show that the strong back-flow in the diffuser of Venturi tube can intensify the collision of gas-liquid phases and crush more drops,while the excessive amount of liquid phase in the Venturi tube increases the droplet density and collision probability of droplet in motion,leading to larger droplet size.The suitable geometric size for Venturi tube reactor are 100 mm-inner diameter,10 mm-throat diameter,5 mminner diameter of drainage tube and the gas flow rate of 20.5 m3/h.
Spray pyrolysis rare-earth chloride is a new process to produce rare-earth oxides,but there are some shortages at present such as the poor atomization effect of spray pyrolysis equipment and the non-uniform distribution of the droplet size after atomization.A Venturi tube spray pyrolysis reactor was designed and particle image velocimetry technology combined with MATLAB image processing technology was used to analyze the effects of gas flow rate,the size of Venturi tube and drainage tube on the atomization.The results show that the strong back-flow in the diffuser of Venturi tube can intensify the collision of gas-liquid phases and crush more drops,while the excessive amount of liquid phase in the Venturi tube increases the droplet density and collision probability of droplet in motion,leading to larger droplet size.The suitable geometric size for Venturi tube reactor are 100 mm-inner diameter,10 mm-throat diameter,5 mminner diameter of drainage tube and the gas flow rate of 20.5 m3/h.
引文
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[11]向丽.轻稀土氯化物静态焙烧制备稀土氧化物的研究[D].沈阳:东北大学,2010.(Xiang Li.Study on the preparation of light rare earthoxide from rare earth chlorideroasted statically[D].Shenyang:Northeastern University,2010.)
[2]Liu Z G,Li M,Hu Y H,et al.Preparation of large particle rare earth oxides by precipitation with oxalic acid[J].Journal of Rare Earths,2008,26(2):158-162.
[3]Xiao H Y,Ai Z H,Zhang L Z.Nonaqueous sol-gel synthesized hierarchical CeO2 nanocrystal microspheres as novel adsorbents for wastewater treatment[J].The Journal of Physical Chemistry:C,2009,113(38):16625-16630.
[4]Ni J B,Gao J,Wei H,et al.Controlled hydrothermal synthesis and excellent optical properties of two different kinds of CeO2 nanocubes[J].Journal of Materials Science:Materials in Electronics,2017,28(15):11029-11033.
[5]Wang F,Zhang Y,Zhao Y X,et al.Novel synthesis of CeO2nanoparticles within formamide/Tri(ethyleneglycol)monododecyl ether/n-octane nonaqueous microemulsion systems[J].Journal of Dispersion Science and Technology,2011,32(6):840-845.
[6]Dudek M,Mosialek M,Mordarski G,et al.Ionic conductivity of the CeO2-Gd2O3-SrO system[J].Archives of Metallurgy&Materials,2011,56(4):1249-1255.
[7]Liao X H,Zhu J J,Xu J Z,et al.Preparation of monodispersed nanocrystalline CeO2 powders by microwave irradiation[J].Chemical Communications,2001,10(10):937-938.
[8]Shimada H,Yamaguchi T,Suzuki T,et al.High power density cell using nanostructured Sr-doped SmCoO3 and Sm-doped CeO2 composite powder synthesized by spray pyrolysis[J].Journal of Power Sources,2016,302:308-314.
[9]Suresh R,Ponnuswamy V,Mariappan R,et al.Influence of substrate temperature on the properties of CeO2 thin films by simple nebulizer spray pyrolysis technique[J].Ceramics International,2014,40(1):437-445.
[10]李天旻.草酸沉淀法/碳酸氢铵沉淀法制备稀土氧化物粉末[D].上海:华东理工大学,2013.(Li Tian-min.Precipitation of oxalic acid/ammonium bicarbonate for preparation of rare earth oxide powders[D].Shanghai:East China University of Science and Technology,2013.)
[11]向丽.轻稀土氯化物静态焙烧制备稀土氧化物的研究[D].沈阳:东北大学,2010.(Xiang Li.Study on the preparation of light rare earthoxide from rare earth chlorideroasted statically[D].Shenyang:Northeastern University,2010.)
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