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针对间歇操作萃取工艺生产能力低,而逆流连续操作萃取工艺返混严重等问题,研究提出了轻重相交替进料操作的萃取工艺,并对轻重相交替进料筛板萃取塔中的传质性能进行了研究。以煤油-苯甲酸-水为萃取体系,采用单个液滴的传质模型来计算萃取塔的分散相总传质系数,并研究了分散相流速、连续相流速、液滴上升速度以及塔板间距对分散相总传质系数的影响。实验得到分散相总传质系数Kod的数值在3.49?10?5~5.47?10?5 m?s?1,总分散相存留分数在1.63%~4.37%。结果表明轻重相交替进料筛板萃取塔的分散相总传质数高于Kühni搅拌萃取塔、脉冲萃取塔和振动挡板塔,并且流量变化对Kod的影响小,返混效应弱,总分散相存留分数小,不易液泛。 相似文献
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以上-煤油为介质,在内径为0.031m的往复振动板式萃取塔内研究了此塔的分散相持液量、轴向混合和液滴大小。研究表明分散相持液量与板振幅、频率、连续相流速和分散相流速有关;Sauter平均直径与板振幅、频率有关。应用脉冲响应法测试此塔的轴向混合,以无因次方程对轴向混合系数进行关联。 相似文献
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脉冲筛板萃取塔是核工业等领域中最常用的萃取设备之一,为深入了解脉冲筛板萃取塔中两相流行为规律,使用CFD-PBM模型对脉冲筛板萃取塔中由有机相(30%TBP-正十二烷)、水相(HNO3水溶液)组成的体系进行两相流过程模拟分析,模拟结果与实验数据吻合较好,分散相存留分数和Sauter平均液滴直径的相对偏差仅为8.28%和5.54%;随脉冲速度增加,Sauter平均液滴直径减小,液滴直径分布更均匀,分散相存留分数增加,特性速度减小;两相表观速度对液滴直径影响较小,分散相表观流速增加有利于提高分散相存留分数,而连续相表观流速影响不大;发生液泛时分散相液泛表观速度随连续相液泛表观速度增大而减小,随脉冲速度增加液泛通量先增后减,存在极值。 相似文献
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气体搅拌萃取过氧化氢实验研究 总被引:1,自引:0,他引:1
在内径为50 mm的筛板塔内,研究了空气-水-蒽醌工作液三相体系萃取过氧化氢过程.萃取温度为40℃,空气和分散相的表观流速分别为(1.31~3.22)×10-3m·s-1和(1.27~1.70)×10-3 m·s-1,分散相和连续相的表观流速之比为50:1.结果表明,在普通液-液萃取过氧化氢过程中引入气体作搅拌,可减小分散相的液滴直径,增大相际接触面积,明显提高萃取效率,降低萃余相中过氧化氢的含量.传质单元高度随气体表观流速的增加而降低,传质系数随气体表观流速的增加而增大. 相似文献
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选择正丁醇-丁二酸-水作为实验体系,以有机相为分散相,在φ100mm的塔内系统地研究了单降液管、双降液管和三降液管三种塔板的两相流动特性和传质效率,并对其进行了比较。研究结果表明,在相同的操作条件下,多降液管大孔筛板塔比单降液管塔内的动态存留分数大,板下静液层高度小的特点,同时多降液管筛板塔比单降液管筛板塔具有更高的塔效率。 相似文献
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在筛板萃取塔中引入气体搅动,既能明显提高装置的传质效率,又能大幅提高装置处理能力。筛板塔的通量随气速的变化规律与填料塔有显著区别,其性能研究有重要意义。利用煤油(苯甲酸)-水-空气体系,考察了气体搅动和筛孔直径对萃取塔流体力学和传质性能的影响。结果表明,随着表观气速的增加,气含率、分散相含率、液泛速率和传质效率均明显增加。但过高的气速也会导致分散相的过于分散和乳化,传质性能下降,直至液泛。不同直径的筛孔相比,较小的筛孔使分散相停留时间延长,分散相含率和传质效率提高,但液泛速率和处理能力降低。 相似文献
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M. H. I. Baird 《加拿大化工杂志》1991,69(6):1287-1301
The solvent extraction area is perceived by some chemical engineers as being mature and fully developed. The present review shows that this is not the case. Many chemical engineering problems must be solved before equipment can be confidently designed from first principles. The review also outlines progress in extraction process chemistry, and in new techniques such as membrane extraction. 相似文献
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A mathematical model has been developed to simulate and predict the dynamic behavior of liquid extraction counter current operations in mixer-settler units. Murphree efficiency has been included in the model. The behavior of a multistage glass mixer-settler has been studied under start-up transient conditions. Very good agreement between the simulation results and the experimental findings have been obtained. The simulation results showed that this model can efficiently be used to determine the optimum number of stages, the capacity of each stage, the phase ratio and the time required for each unit to attain steady state conditions. Other controlling parameters in operating such units are investigated. 相似文献
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张文兵 《化学推进剂与高分子材料》2004,2(4):47-48
根据生产实践,总结蒽醌法生产双氧水中影响萃余液中双氧水含量的各种因素,指出萃余液中H2O2超标的危害,找到控制萃余的有效途径。 相似文献
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番茄红素含量测定中提取方法研究 总被引:1,自引:0,他引:1
采用紫外一可见分光光度法测定番茄酱中番茄红素的含量。在提取时间,提取次数,提取剂的选择等方面考察了影响番茄红素测定效果。试验结果表明:影响番茄酱中番茄红素的提取因素主次顺序为:料液比〉混合液〉提取时〉间提取次数:采用乙酸乙酯+乙醇(9+1)做提取剂,料液比为1:2,提取时间为30min.提取次数为1次,为番茄酱中番茄红素测定提取的最优组合。 相似文献
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竹叶黄酮提取分析方法的研究及其新进展 总被引:2,自引:0,他引:2
从竹叶黄酮的基本性质着手,根据其溶解性,显色反应等特性,选取适当的提取方法。综述了五种应用较广泛的提取新方法、新技术,及分析方法,并简要论述了各种新技术和方法的原理以及应用于竹叶黄酮工业生产方面的情况。 相似文献
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Lorenzo RA Carro AM Alvarez-Lorenzo C Concheiro A 《International journal of molecular sciences》2011,12(7):4327-4347
Template removal is a critical step in the preparation of most molecularly imprinted polymers (MIPs). The polymer network itself and the affinity of the imprinted cavities for the template make its removal hard. If there are remaining template molecules in the MIPs, less cavities will be available for rebinding, which decreases efficiency. Furthermore, if template bleeding occurs during analytical applications, errors will arise. Despite the relevance to the MIPs performance, template removal has received scarce attention and is currently the least cost-effective step of the MIP development. Attempts to reach complete template removal may involve the use of too drastic conditions in conventional extraction techniques, resulting in the damage or the collapse of the imprinted cavities. Advances in the extraction techniques in the last decade may provide optimized tools. The aim of this review is to analyze the available data on the efficiency of diverse extraction techniques for template removal, paying attention not only to the removal yield but also to MIPs performance. Such an analysis is expected to be useful for opening a way to rational approaches for template removal (minimizing the costs of solvents and time) instead of the current trial-and-error methods. 相似文献