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汽—液—液三相与汽—液两相塔板效率比较 总被引:1,自引:0,他引:1
本文通过小型精馏塔及600×150 mm~2矩形模拟塔的实验,对比研究了气(汽)-液两相和气(汽)-液-液三相的塔板效率。并就物系性质(表面张力梯度、液体粘度或分散粘度),两液相体积比,气速及操作工况对传质的影响进行了研究。提出三相传质和两相传质差异的主要因素,得出估算三相精馏塔板效率的关联式。 相似文献
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宝塔罩型塔板性能研究 总被引:7,自引:0,他引:7
开发了一种宝塔罩型塔板。该塔板是在塔板上设置数个由板孔、升气筒、塔型罩、进液孔所构成的豆塔罩单元,在单元内气液呈喷射状态接触,实现两相传热传质。流体力学性能和传质性能研究证明:该塔板压降、氧解析效率、漏液等性能与新型垂直筛板相当,但雾沫夹带要比新型垂直筛板低。因而该塔板具有较大的生产处理能力和较宽的稳定操作范围。 相似文献
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旋流塔板有复杂的气液接触状态。对应于一定的气液接触现象,气液接触状态可分为倾泻区、泡花区、喷射区和全喷射区。在四种接触状态下,塔板有效压降与气速的关系有明显的差别。以有效压降随气速变化规律的转化点作为气液接触状态的转化点,确定了塔板上各种气液接触状态的区域,并关联了接触状态转化点的操作条件。对喷射区有效压降的分析得到,有效压降主要决定于塔板上液体产生的静压降,气体径向速度可以忽略,而使喷射区内有效压降不受气速影响。全喷射区内,气速影响溢流管和溢流锥的溢流能力,而使气速明显地影响塔板有效压降。泡花区内,漏液量随气速的增大而减小;因此,气速影响塔板有效压降。适当地简化流况,提出了有效压降关联式,利用实验数据确定了其中的参数。 相似文献
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《化学工程》2017,(9):24-28
在内径为600 mm的不锈钢塔内,以空气-水-氧气为物系,对固旋阀塔板的流体力学和传质性能进行研究。测定了塔板传质效率和雾沫夹带量,并与F1浮阀塔板进行对比;通过计算流体力学软件Fluent对固旋阀塔板上气相三维流场进行了数值模拟。实验结果表明:当液相喷淋密度L=5 m~3/(m~2·h)时,随着气体负荷的逐渐增大,固旋阀塔板的传质效率从小于F1浮阀到逐渐接近F1浮阀,且在实验最大气体负荷条件下超过了F1浮阀;当液相喷淋密度较大时,固旋阀塔板的传质效率高于F1浮阀塔板,且随着气体负荷的增大,差异越来越明显;固旋阀塔板的雾沫夹带比F1浮阀塔板低50%—60%,因此具有更高的气相负荷操作上限。Fluent软件模拟结果表明,固旋阀塔板中旋转流场的存在促使液层分布更均匀,气液传质得到进一步强化。 相似文献
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Henry Sawistowski 《化学,工程师,技术》1978,50(10):743-748
Hydrodynamic and mass transfer behaviour of sieve plates in the spray and bubble regimes . An attempt is made to set up idealized hydrodynamic models for the bubble and spray regimes on sieve plates and thus to provide a basis for calculation of mass transfer and concentration ratio. Comparison of the dependence of plate efficiency in the two regimes on various parameters indicates the importance of being able to determine a practical phase transition point. This was defined on the basis of the contribution of the bubbles and droplets to the overall interfacial area and compared with the transition points of other authors. The operation of columns in the spray regime, formerly regarded as undesirable, now possesses considerable industrial significance. This was mentioned by Zuiderweg [29] in his Underwood lecture of 1973. Since that time larger perforations and higher gas velocities have been employed. There has consequently been a significant shift of sieve plate behaviour from the bubble to the spray regime. It is estimated that almost 80% of all industrial sieve plate columns now operate in the spray regime and should be specifically designed for such operation. 相似文献
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Wei Liu Bingqi Xie Chenghao Zhang Xiaonan Duan Jisong Zhang 《American Institute of Chemical Engineers》2023,69(7):e18004
Micro-packed bed reactors (μPBRs) have the advantages of high heat and mass transfer efficiency and excellent safety, and they have been successfully applied to hydrogenation and oxidation reactions. However, the study of gas–liquid flow regimes in the μPBR, which is essential for the mass transfer modeling and reactor scale-up, is still insufficient due to the limitation of micro-scale and complexity of capillary force. In this work, the flow regimes in the two-dimensional μPBR were systematically studied by visual method utilizing a high-performance camera. Four typical flow regimes and characteristics were captured, and flow regime transition was revealed. Effects of gas and liquid superficial velocities, liquid physical properties, and particle sizes on liquid spreading areal fraction and pressure drop were investigated. Flow regime transition correlation of churn flow and pseudo-static flow in the μPBR was provided for the first time based on the summary of the current and previous published results. 相似文献
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Mass Transfer and Liquid‐Film Formation in a Spray Tower for SO2 Removal in Sodium Hydroxide Solution
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Spray towers allow for controlling air pollution in which a liquid is sprayed in small droplets to produce a large interfacial area for mass transfer between a gas and a liquid phase. An experimental study of a spray tower for removing SO2 is described. The experiments were carried out under different operating conditions by varying the gas velocity, liquid flow rate, and SO2 concentration. SO2 removal efficiency, volumetric mass transfer coefficient, and liquid‐film formation as a result of the collision of droplets against the tower wall are investigated. Removal efficiency and volumetric mass transfer coefficient are analyzed as a function of gas velocity, liquid flow rate, and SO2 concentration, while liquid‐film formation is evaluated as a function of tower height. The results indicate high removal efficiency. Correlations to predict the volumetric mass transfer coefficient are also proposed. 相似文献
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The usual models for predicting the effect of liquid mixing assume a diffusion model as is reasonable for the foam and froth regimes. Here a one-dimensional spray regime model is developed with finite spray “throw,” allowing for inlet and outlet conditions and the effect of spray mixing on tray efficiency is evaluated. The extension to less restricted models is indicated. 相似文献
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<正>筛板塔是应用历史最久的塔型之一。至今人们仍在对筛板塔进行大量的研究,但对筛板塔处于不同鼓泡层的结构及筛板塔各操作状态之间的划分这一课题,还基本上限于一些定性的直观描述。筛板塔的各操作状态之间主要由两点速度划分,即漏液气速和喷射转变气速。在他们之间筛板处于泡沫工况,当气速高于喷射转变气速时,筛板塔处于喷射工况。这两种工况是人们最感兴趣的,这不仅因为在工业上这两种工况用得最多,而且还因为在流动泡沫工况下气体为分散相,液体为连续相,一旦转变为喷射工况就发生了相变,气体变为连续相,原来是连续相的液体则被气体吹散为小液滴的分散相。这种工况的转变必然强烈地影响着两相间的传质,要掌握塔板上两相间的传质规律,首先要确定它是处于何种工况。 相似文献
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The usual models for predicting the effect of liquid mixing assume a diffusion model as is reasonable for the foam and froth regimes. Here a one-dimensional spray regime model is developed with finite spray “throw,” allowing for inlet and outlet conditions and the effect of spray mixing on tray efficiency is evaluated. The extension to less restricted models is indicated. 相似文献