Application of an intensified narrow channel reactor to the aqueous phase precipitation of barium sulphate
Application of an intensified narrow channel reactor to the aqueous phase precipitation of barium sulphate
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DOI：
10.1016/j.jcis.2006.08.056
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发表时间：
2007-01-01
影响因子：
9.9
通讯作者：
Boodhoo, K. V. K.
中科院分区：
文献类型：
--
作者：
McCarthy, E. D.;Dunk, W. A. E.;Boodhoo, K. V. K.
在窄通道反应器中，氯化钡（BaCl 2）和硫酸钠（Na 2 SO 4）进行均相液相反应，生成硫酸钡（BaSO 4）沉淀。研究了在不同反应物过饱和度下，通道尺寸和通道停留时间对晶体尺寸、晶体尺寸分布、成核速率、晶体形态和反应物转化率的影响。我们的研究结果表明，最小的颗粒尺寸时，过饱和比和通道速度高的青睐。在初始过饱和比为4483（0.1M）时，在水力直径为0.5mm和长度为20 cm的通道中观察到的最小平均粒径约为0.2 μ m，这对应于产生最高成核速率的条件。还观察到粒度取决于转化成产物的转化率，当转化率在30 - 40%范围内时形成最小的颗粒。已经达到超过60%的转化率，但随着过饱和度的增加和停留时间的减少，存在可检测的限制效应。在搅拌槽条件下在类似的过饱和水平下进行的实验表明，与窄通道反应器中实现的相比，颗粒尺寸始终较大，并且颗粒尺寸分布宽得多。在窄通道中形成的晶体的扫描电子显微镜（SEM）图像显示，球形颗粒在最小通道中以高速度占主导地位，而在较大通道中获得粗糙的片状晶体。在反应一分钟后，在高过饱和比下也观察到更大的附聚倾向。(c)2006年爱思唯尔公司All rights reserved.
A homogeneous liquid phase reaction between barium chloride (BaCl2) and sodium sulphate (Na2SO4) was conducted in a narrow channel reactor to produce barium sulphate (BaSO4) precipitate. The effects of channel dimensions and channel residence times on crystal size, crystal size distribution, nucleation rates, crystal morphology and conversion of reactants were investigated at different levels of reactant supersaturation ratio. Our results indicate that the smallest particle sizes are favoured when supersaturation ratios and channel velocities are high. The minimum average particle diameter observed was approximately 0.2 mu m in a channel of hydraulic diameter 0.5 mm and length 20 cm at an initial supersaturation ratio of 4483 (0.1 M), which correspond to conditions giving rise to the highest nucleation rates. It has also been observed that particle size depends on the conversion to product, the smallest particles being formed when conversion lies within the range of 30 to 40%. Conversions in excess of 60% have been reached but there is a detectable limiting effect with increased supersaturation and reduced residence times. Experiments conducted at similar levels of supersaturation under stirred tank conditions showed that particle size was consistently larger and particle size distribution was much broader than that achieved in the narrow channel reactor. Scanning electron microscopy (SEM) images of the crystals formed in the narrow channels show that spherical particles dominate in the smallest channels at high velocities whilst coarse, tabular crystals are obtained in the larger channels. Greater tendency to agglomerate is also observed at high supersaturation ratios, after one minute of reaction. (c) 2006 Elsevier Inc. All rights reserved.