Process intensification: Visual study of liquid maldistribution in rotating packed beds
Process intensification: Visual study of liquid maldistribution in rotating packed beds
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DOI：
10.1016/0009-2509(95)00367-3
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发表时间：
1996-04
影响因子：
4.7
通讯作者：
J. Burns;C. Ramshaw
中科院分区：
文献类型：
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作者：
J. Burns;C. Ramshaw
实验设施图1显示了目视观察中使用的RPB的横截面。一个10厘米厚、内径和外径分别为7厘米和32厘米的填料环被安装在一个转速高达1620rpm的转子上。使用网状聚氯乙烯(Declon Filtren HC10)(图9和图10)。它的孔隙度为0.95，估计单位体积的表面积为1500米2米-3。液体被注入到包装材料的内环并留在外围。旋转床内有三种类型的液体流动，如图2所示。气体通过60x2 mm的小孔注入填料，径向深度为14厘米(图2)。L-H)。液体密封(图1-LS)迫使气体逆流移动到液体并从中心离开。使用有机镜前盖可以观察到流动。使用35 mm相机和闪光灯来拍摄填料内的流动。白色乳胶漆和水的溶液被用来与黑色包装形成对比，乳胶漆的体积为3-7%。在此浓度下的溶液近似为牛顿溶液，表面张力为5.0×10-2Nm-1，运动粘度在1.6×10-6m2 S-1~3.3x10-6m2 S-1之间。该系统的典型液体流量为1.83×10~(-4)m~3 S~(-1)，相当于83 kg m~(-2)S-a的内环流量。螺旋线的形状随转速的增加而变化不大，当转速超过1000rpm时，螺旋线的锋面速度为0.8-1.4m，S-1。当整个有机玻璃盖被内径为19厘米的部分版本取代时，螺旋流消失，而溪流仍然可见(图4)。这将表明螺旋是一种壁流形式，而溪流是整个填料中液体流动的一种特征。进一步的全覆盖试验表明，当使用较少的液体喷射点时，螺旋壁流动被加强。这归因于液体在更宽的喷射射流冲击下的轴向扩散增加。
EXPERIMENTAL FACILITY Figure 1 shows a cross section of the RPB used in the visual observations. An annulus of packing material 10 cm thick with inner and outer diameters of 7 and 32 cm, respectively, was mounted in a rotor capable of up to 1620rpm. A reticulated PVC packing (Declon Filtren HC10) was used (Figs 9 and 10). This had a porosity of 0.95 and estimated surface area per unit volume of 1500 m 2 m-3. Liquid was injected into the inner ring of packing material and left at the periphery. Three types of liquid flow within an RPB are shown in Fig. 2. Gas was injected into the packing via 60x 2 mm holes at a radial depth of 14cm (Fig. l--H). A liquid seal (Fig. 1--LS) forced the gas to move countercurrently to the liquid and exit at the centre. A perspex front cover was used to allow observation of the flow. A 35 mm camera and strobe light were used to photograph the flow within the packing. A solution of white emulsion paint, 3-7% by volume, and water was used to provide a contrast against the black packing. The solution at these concentrations is approximately Newtonian with a surface tension of 5.0 x 10-2 N m-1 and kinematic viscosity between 1.6 x 10-6 m 2 s-1 and 3.3 x 10-6 m 2 s-1. The typical liquid flow rate used in this system was 1.83 x 10-4 m 3 s-1, equivalent to 83 kg m-2 s-a at the inner ring. shape of the spiral was seen to vary little with increasing rotational speed with a frontal velocity of 0.8-1.4 m s-1 for speeds in excess of I000 rpm. The spiral flow was seen to disappear when the full perspex cover was replaced with a partial version, having an inner diameter of 19 cm, while rivulet flow remained visible (Fig. 4). This would indicate that the spiral is a form of wall flow whereas the rivulets are a feature of liquid flow throughout the packing. Further tests with a full cover revealed that the spiral wall flow was accentuated when fewer liquid injection points were used. This was attributed to the increased axial spread of liquid on impact from wider injection jets.