转盘萃取塔内连续相轴向混合的研究(摘要)

本文从转盘塔内流体流动特性出发研究了塔内连续相轴向混合。应用光导纤维测试仪测定脉冲示踪的浓度响应。这种方法基本上不影响塔内流场,消除滞后现象,所得讯号可记录于磁带,直接送计算机处理。一个直径为D的液滴由于具有表面能     

开孔转盘塔(RPDC)连续相流体轴向混合的研究

本文采用非理想脉冲示踪技术,借助于计算机数据采集系统,在无传质条件下对RPDC连续相流体的轴向混合进行了研究。用时间域最小二乘拟合法求取了轴向混合参数,分析了RPDC连续相轴向混合的机理,得到了描述连续相流体轴向混合的数学表达式。     

由转盘塔内连续相溶质浓度轴向分布 估算传质系数和轴向混合系数的研究

根据转盘萃取塔内连续相溶质浓度的轴向分布进行了参数估算.在估算中应用液滴尺寸分布,将带轴向混合的柱塞流模型应用于塔内连续相,将前混模型应用于分散相.参数估算结果表明:应用d_(32)所获得的连续相轴向混合系数E_c和传质系数k_c的估算值比应用液滴尺寸分布所得的E_c、k_c的估算值偏高;如果忽略液滴生成过程传质的影响,k_c的估算值略有增加,而E_c的估算值则明显偏高.     

由转盘塔内连续相溶质浓度轴向分布 估算传质系数和轴向混合系数的研究

根据转盘萃取塔内连续相溶质浓度的轴向分布进行了参数估算.在估算中应用液滴尺寸分布,将带轴向混合的柱塞流模型应用于塔内连续相,将前混模型应用于分散相.参数估算结果表明:应用d_(32)所获得的连续相轴向混合系数E_c和传质系数k_c的估算值比应用液滴尺寸分布所得的E_c、k_c的估算值偏高;如果忽略液滴生成过程传质的影响,k_c的估算值略有增加,而E_c的估算值则明显偏高.     

脉冲筛板萃取柱中连续相的轴向混合

通过示踪剂实验方法对38mm脉冲筛板萃取柱中连续相的轴向混合进行了研究。分别采用亚甲基蓝溶液和氯化钾溶液为示踪剂。实验过程中,首先采用"扰动-响应"技术实测了示踪剂的停留时间分布(RTD)曲线,然后依照轴向扩散模型(ADM)应用最小二乘法拟合求出连续相的轴向混合系数Ec,并分析了连续相表观流速、分散相表观流速、脉冲强度对于Ec的影响。实验结果表明,示踪剂浓度、径向取样位置和轴向取样位置对轴向混合系数Ec值的影响可以忽略,轴向混合系数Ec随着脉冲强度和两相表观流速的增加而增大。最后在本实验参数范围内,拟合出了连续相的轴向混合系数随操作参数变化的经验关系式,与实验结果对比,相对偏差在±20%以内。     

多层鼓泡塔中液体轴向混合的研究

本文分两部分,在第Ⅰ部分中以实验验证了级内完全混合——级间有返混模型用于多层鼓泡塔的适用性。在空气-水系统中,用稳态示踪方法分别测定各级间的返混系数。从统计力学的观点,将本文及西胁昭雄在大孔径、大开孔率范围的实验结果进行了统一关联,得到一较普遍的关系式。第Ⅱ部分研究了碳酸镍铵溶液中不饱和硫化物在鼓泡塔中的氧化行为,应用返混模型及氧化速度方程,对塔内轴向不饱和硫浓度分布进行了计算,与实验结果比较,两者能基本相符。解析求出了塔内最佳氧化温度,也能与实验结果符合。     

电导法连续测定转盘塔中氯化钾的相对含量

一、前言为了更科学地设计、控制转盘萃取塔,就必须深入研究其流通能力、轴向混合等性能。通过示踪物质的测定了解一定操作条件下的返混情况则是一种方     

粘度对填料塔中液相轴向混合的影响

在液相粘度0.0008—0.014Pa·s的范围内,针对粘度对填料塔中液相轴向混合的影响进行了研究,得知该影响可用下式表示:Pe_d=AFr_1~B(v_1/v_w)~C,式中的(v_1/v_w)定义为粘度校正因子,C值分别为-0.15(载点以下)和-0.138(载液区).     

轻重相交替进料筛板萃取塔中的传质性能研究

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。     

多层筛板并流鼓泡塔中液体轴向混合的研究

本文检验了级内完全混合-级间有返混的模型对于多层筛板鼓泡塔中液体轴合混合的适用性。在空气-水系统中,用示踪剂研究了级间返混系数与设备参数、操作参数间的关系,对返混机理进行了考察,得到了返混系数与主要设备参数、操作参数间的关系式。实验中发现,气体分布板附近四层的返混系数受到气体分布板即端效应的影响。因此只有第四层以上的返混系数才逐层相等。     

聚并-分散脉冲筛板萃取塔的传质与轴向混合特性

A new configuration of coalescence-dispersed pulsed-sieve-plate extraction column (CDPSEC) was developed, and the mass transfer and axial mixing characteristics were evaluated with the two-point dynamic method.The influence of operation conditions was discussed with experimental results, showing that the mass transfer performance of CDPSEC mainly depends on the energy input and the holdup of dispersed phase. Higher energy input results in higher holdhp of the dispersed phase, the axial mixing of the continuous phase is suppressed, and the true height of mass transfer unit decreases markedly. On the other hand, higher energy input leads to more serious forward mixing of the dispersed phase, so the energy input should be limited. Accordingly the operation conditions were divided into two regions, and empirical correlations for predicting the mass transfer and axial mixing characteristics in different regions with a satisfactory accuracy were suggested.     

开孔转盘塔分散相滞存率及液滴直径分布的研究

本文在无传质条件下研究了开孔转盘塔(RPDc)内乳液—水体系(W/O/W)的流体力学性能。测定了塔内分散相滞存率x,考察了塔几何条件及操作条件对分散相滞存率x及特性速度U_o的影响。采用因次分析法,建立了x及U_o与塔几何条件及操作条件间的经验关联式。并采用摄影法,对分散相液滴直径及其分布进行了初步研究。实验结果表明,分散相液滴直径的分布可用上限对数正态分布来描述。     

Mass Transfer and Axial Mixing Characteristics in a Coalescence-Dispersion Pulsed-Sieve-Plate Extraction Column

A new configuration of coalescence-dispersed pulsed-sieve-plate extraction column (CDPSEC) was developed, and the mass transfer and axial mixing characteristics were evaluated with the two-point dynamic method. The influence of operation conditions was discussed with experimental results, showing that the mass transfer performance of CDPSEC mainly depends on the energy input and the holdup of dispersed phase. Higher energy input results in higher holdup of the dispersed phase, the axial mixing of the continuous phase is suppressed, and the true height of mass transfer unit decreases markedly. On the other hand, higher energy input leads to more serious forward mixing of the dispersed phase, so the energy input should be limited. Accordingly the operation conditions were divided into two regions, and empirical correlations for predicting the mass transfer and axial mixing characteristics in different regions with a satisfactory accuracy were suggested.     

Continuous Phase Mixing on Crossflow Extraction Sieve Trays

Abstract

Axial dispersion of a crossflowing continuous phase was studied in a special experimental system that simulated a “slice” from a large, commercial scale sieve tray extractor. The toluene-water system was used, and Peclet numbers were determined as functions of phase flow rates and tray geometry. It was concluded that for systems with relatively high interfacial tension, which give characteristically low point efficiencies, axial mixing is not an important issue in the design of sieve tray extractors.     

Performance Analysis of a Continuous Rotating Annular Electrophoresis Column

Abstract

A new continuous electrophoresis column is proposed which will allow for the continuous separation of industrial scale multicomponent mixtures. Computer simulated calculations predict steady-state bed temperature, separation distance, and power requirements. The proposed design compares favorably to previous designs in terms of minimizing peak bed temperature and power consumed.     

用时间域最小二乘拟合法研究萃取柱中的轴向混合

本文以非理想脉冲注入的扰动-响应技术,进行萃取柱轴向混合的研究。各种参数估值方法的比较表明,时间域最小二乘拟合法较为精确。本文还讨论了参数估值的不定性问题和计算时间问题。在标准结构的脉冲筛板柱内研究了脉冲振幅和频率对轴向混合系数的影响。     

多级搅拌塔气液体系的轴向混合和气含率

采用改进的Rushton六直叶涡轮桨,在内径为80 mm的多级搅拌塔中,以氮气-水体系为研究对象,考察了液速、气速和搅拌桨转速对连续相轴向混合和气含率的影响.结果表明:在液速1.38×10-4～4.42×10-4 m/s、气速5.53×10-2～17.68×10-2 m/s和转速1.67～13.33 r/s条件下,轴向扩散系数随着液速和气速的增加而增大,随着搅拌桨转速的增加先减小后增大;平均气含率随着液速、气速及搅拌桨转速的增加而增大.根据实验数据得到了连续相轴向扩散系数和平均气含率的关联式,其计算值与实验值误差较小,分别小于15%和10%.     

多级搅拌塔气液液系统的轴向混合

本文在内径为５４ｍｍ，级数为１６的多级搅拌塔中，研究了空气－水－煤油系统的轴向混合性质。讨论了搅拌转速、水相流速、有机相流速及气相流速对液体连续相和分散相轴向混合的影响。得到了操作范围内描述塔内轴向扩散系数的关联式。对连续水相：Ｅｃ＝０．７４５·Ｎｓ０．５３０·ｕｇ０．４５９·ｕｃ０．６９１·ｕｄ０．３１９对分散有机相：Ｅｄ＝２１．９２·Ｎｓ０．４６５·ｕｇ０．８９８·ｕｃ０．２５８·ｕｄ０．７６２