Effects of Gas‐Agitation and Packing on Hydrodynamics and Mass Transfer of Extraction Column

The effects of gas‐agitation and packing on hydrodynamics and mass transfer were investigated through experiments with air‐kerosene (benzoic acid)‐water system and corrugated‐packing of calendering plate with hole. The holdup of gas, holdup of dispersed liquid phase and mass transfer coefficient increase and the flooding velocity decrease with the increase in superficial gas velocity. Over‐agitation of gas causes over‐dispersion and emulsification of dispersed liquid phase, reduction of mass transfer performance and even flooding. The mass transfer performance of a packed column is far better than that of an unpacked column.     

Hydrodynamics and Mass Transfer in a Lab‐Scale Stirred‐Pulsed Extraction Column

An extraction column with energy input through simultaneous stirring and pulsation allows for efficient countercurrent extraction on lab‐scale. While stirring generates small droplets with a narrow droplet size distribution, pulsation supports the axial transport of the dispersed phase, enabling countercurrent flow on this small scale. By studying the influence of several operating parameters, fundamental mechanics and characteristics of the column are revealed. Increasing the stirrer speed leads to smaller droplets and higher extraction performance as well as lower maximum throughput. The maximum throughput is increased by raising the pulsation intensity.     

填料特性对鼓泡填料萃取塔性能影响

填料的结构与表面性能对鼓泡填料萃取塔性能有直接影响。利用空气 煤油 (苯甲酸 ) 水体系 ,测定了未装填料和分别装填板波填料、丝网填料、压延孔环填料的鼓泡萃取塔水力学性能和传质性能。实验表明 ,对未装填料和装有填料的萃取塔 ,气相搅拌都可以显著提高液液两相的接触与传质性能 ;液泛速度随表观气速的增大而下降 ;流道设计合理的规整填料传质性能明显高于散装填料 ;表面光滑的填料分散相滞存率低 ,因而液泛速度较高 ;填料的作用有利于降低轴向返混 ,明显提高萃取塔传质性能。     

复合填料萃取塔操作性能研究

在内径为０．１ｍ，高度为１．０ｍ的玻璃萃取塔中，对四种不同填料用低界面张力体系（正丁醇－丁二酸－水）研究了填料塔的流体力学和传质性能，实验结果表明，用其中的两种填料组合的复合填料萃取塔具有较大的通量和较高的传质效率，可望在工业装置中得到推广应用。     

Two-Stage Countercurrent Enzyme-Assisted Aqueous Extraction Processing of Oil and Protein from Soybeans

Enzyme-assisted aqueous extraction processing (EAEP) is an increasingly viable alternative to hexane extraction of soybean oil. Although considered an environmentally friendly technology where edible oil and protein can be simultaneously recovered, this process employs much water and produces a significant amount of protein-rich aqueous effluent (skim). In standard EAEP, highest oil, protein and solids yields are achieved with a single extraction stage using 1:10 solids-to-liquid ratio (extruded flakes/water), 0.5% protease (wt/g extruded flakes), pH 9.0, and 50 °C for 1 h. To reduce the amount of water used, two-stage countercurrent EAEP was evaluated for extracting oil, protein and solids from soybeans using a solids-to-liquid ratio of 1:5–1:6 (extruded flakes/water). Two-stage countercurrent EAEP achieved higher oil, protein and solids extraction yields than using standard EAEP with only one-half the usual amount of water. Oil, protein and solids yields up to 98 and 96%, 92 and 87%, and 80 and 77% were obtained when using two-stage countercurrent EAEP (1:5–1:6) and standard single-stage EAEP (1:10), respectively. Recycling the second skim obtained in two-stage countercurrent EAEP enabled reuse of the enzyme, with or without inactivation, in the first extraction stage producing protein with different degrees of hydrolysis and the same extraction efficiency. Slightly higher oil, protein and solids extraction yields were obtained using unheated skim compared to heated skim. These advances make the two-stage countercurrent EAEP attractive as the front-end of a soybean biorefinery.     

Hydrodynamics of a Tapered Bubble Column

The hydrodynamic behavior of a single‐stage tapered bubble column using an air‐water two‐phase system has been studied. The experimental results indicate that the holdup increases with increasing superficial gas velocity and bubble slip velocity, while it remains constant with increasing superficial liquid velocity. The gas flow rate has a subtle effect on pressure drop owing to the dynamic pressure recovery stemming from the increase in flow area in the axial direction. The results further suggest that the tapered bubble column shows higher holdup with lower energy dissipation than the conventional bubble columns under similar hydrodynamic conditions. The experimental values of the holdup are in excellent agreement with the well‐known Akita and Yoshida correlation available in the existing literature. Also, the performance of the tapered system has been shown to be much better than that of conventional columns under similar conditions in water/alkaline scrubbing of fly ash and SO₂ either alone or in combination.     

空气搅动的填料萃取塔性能实验研究

引　言气体搅动是一种外加能量的萃取方法 .与机械搅拌相比 ,气体搅动的萃取塔内无运动部件 ,操作稳定 ,结构简单 ,能耗低 .过去已有数篇关于气体搅动的混合 -澄清槽[1] 、喷洒塔[2～ 4 ] 、多级连续萃取器[5] 等无填料的萃取过程水力学性能和传质性能的文献报道 .而在填料塔萃取过程中加入气体搅动技术 ,一方面继承了填料可以有效地降低轴向返混的优越性能 ;另一方面 ,通过外加能量进一步强化液 -液两相接触与传质 ,提高传质系数 ,综合了外加能量的萃取技术和填料萃取技术的优点 .关于这方面的内容目前少有报道[6] .1　实验装置与实验方法…     

喷射型催化精馏塔构件的流体力学性能

对垂直筛板帽罩内装催化剂构成的新型塔构件进行了实验研究。考察了板孔动能因子、催化剂藏量、床层空隙率对塔构件压降、罩体喷出量以及液泛和漏液速度的影响。结果表明:压降随板孔动能因子和催化剂藏量的增加而增大,随床层空隙率的增加而减小;罩体喷出液体量随着板孔动能因子的增加先增大后减小,随床层空隙率的增加而增大,随催化剂藏量的增加而减小;漏液速度随液体流量、藏量的增加而增大,随空隙率增大而减少;液泛速度随床层空隙率、液体流量的增大而减小,随藏量增加而增大。新型塔构件流体力学性能良好。     

填料类型对脉冲填料萃取塔性能的影响

采用３０％ＴＢＰ（煤油）／ＨＡｃ／水体系研究了脉冲填料萃取塔的流体动力学和传质特性,考察了脉冲强度和填普类型对塔性能的影响。实验表明装填ＱＨ－１型扁环的脉冲填料 性能明显优于装填陶瓷和不锈钢拉西环的脉冲塔。文中给出了装填ＱＨ－１型扁环的脉冲填普塔的特性速度和Ｈｏｘｐ的经验计算式。     

聚合-分散脉冲筛板萃取塔两相流动特性

A study on two-phase flow characteristics in a coalescence-dispersion pulsed-sieve-plate extraction column of 150mm in diameter was carried out with a working system of 30% tri-butyl-phosphate (TBP) (in kerosene)-nitric acid-water. The influence of operation conditions on the holdup of the dispersed phase was investigated. According to the analysis of the experimental data, there was a turning point on the curve of ln(Vs) versus ln(l-Φ) under certain pulse intensity. When the holdup is higher than the value at the turning point, the two-phase flow characteristics can be described with the modified Pratt's equation, otherwise a new relation in the form ofΦ=1/2.75uk(uc 4ud) may be used, which is proposed by this study.     

An Improved Correlation of the Mean Drop Size in a Modified Scheibel Extraction Column

The drop size is of fundamental importance in the design of liquid‐liquid extraction columns, the drop size was measured as a function of the geometry, operating conditions, and physical properties of a liquid‐liquid system with no mass transfer in a five‐stage modified Scheibel extraction column. An improved correlation of the mean drop size in the Scheibel extraction column is presented. The correlation was divided into three sections in terms of the Reynolds number. It could be applied in a wide range and could be further used for the study of mass transfer performance of the modified Scheibel extraction column.     

机械搅拌萃取塔中影响传质效果的几个因素

对浆叶旋转式和筛板振动式两种机械搅拌萃取塔进行了传质方面的研究。通过测试大量的实验数据。及计算绘制的图表，校系统地考察分析了旋转（振动）频率，筛板振幅，两相界面，停留时间即取样时间等因素对传质效果的影响，并确定出了最适宜的操作条件。     

A Study on Hydrodynamics and Heat Transfer in a Bubble Column Reactor with Yeast and Bacterial Cell Suspensions

Hydrodynamics and heat transfer experiments were carried out in a slurry bubble column with air‐water‐yeast cells and air‐water‐bacteria cells systems to investigate gas hold‐up, bubble characteristics and heat transfer coefficients with cell concentrations of 0.1% w/w and 0.4% w/w and superficial gas velocity up to 0.20 m/s. The gas hold‐ups and heat transfer coefficients were found to increase with increasing gas velocity and cell concentration. The heat transfer coefficients were higher at the centre of the column as compared to the near wall region. The development of empirical correlations to predict the heat transfer coefficient in two‐ and three‐phase systems was carried out with ±15% confidence interval at most.     

闭式涡轮搅拌萃取塔液滴直径的估算

本文利用均匀各向同性湍流特性分析连续相湍流脉动液滴大小的影响，得出搅拌强度和液滴平均直径之间的关系，根据所使用的三种塔几何结构所得的实验数据检验。理论分析结果与实验所得结果较好地相符。本文也讨论了分散相存留分数对平均液滴直径的影响。     

振动筛板塔液-液萃取的流体力学及传质性能的研究

以煤油－苯甲酸－水为实验体系,对往复振动筛板塔（内径D＝0．041m,塔高Z＝0．895m）的流体力学及性质性能进行了研究。实验测定了分散相液滴的直径,分散相的持液量及传质单元高度并对其影响因素进行 了关联。     

Dispersed Phase Holdup in a Tall and Low Plate Free Area Liquid Pulsed Sieve-Plate Extraction Column

Dispersed phase holdup is studied in a tall and low plate free area pulsed sieve-plate extraction column. The 5.0 cm internal diameter column consists of 80 number of plates with percent free area of 13.5. The effects of pulse velocity (product of amplitude and frequency), superficial phase velocities, and solute addition are studied for five liquid-liquid systems with a wide range of interfacial tensions. The experimental holdup data is tested against the most widely recommended correlations and a new correlation has been developed that best fits the data.     

再分布板和径向挡板对淤浆鼓泡床流体力学特性的影响

研究了在以空气-水-石英砂为实验体系的淤浆鼓泡床中加入内构件?再分布板和径向挡板对床层气含率和固含率的影响,并与不加内构件的情况进行了对比. 实验结果表明,再分布板可明显提高床层的平均气含率,且开孔孔径越小,作用越显著;但径向挡板的作用不明显;再分布板和径向挡板均可改善气含率和固含率的轴向分布,且不会大幅度增加压降. 通过对Smith关联式进行修正,得到了带有再分布板的淤浆鼓泡床中床层平均气含率的经验关联式.     

The Use of an Ionic Liquid in a Karr Reciprocating Plate Extraction Column: Drop Size Distribution

Ionic liquids (ILs) offer a new class of fluids for solvent extraction. This work presents drop size distribution data for the [bmim][PF₆]/water system and examines the basis of existing drop size prediction models developed for traditional organic/aqueous systems in a Karr reciprocating plate column and recommends how they may be used for these new class of materials.     

Modelling and Simulation of a Complete Supercritical Fluid Extraction Plant with Countercurrent Fractionation Column

The most complete dynamic model to date of a supercritical fluid extraction (SFE) plant is presented and experimentally validated. The SFE flowsheet is modularly organized into a set of detailed sub-models of the main unit operations, including the extraction packed column, the supercritical solvent heat exchanger, the product recovery and solvent regeneration column, and the solvent make-up. The modules are interconnected through appropriate boundary conditions that establish continuity of mass, momentum, and energy. The present model significantly improves our previous modeling efforts by, among other features, including the gas compressor unit, extending the operation of the whole plant to nonisothermal conditions, and upgrading the packed column model for reflux mode operation. The SFE model was validated against experimental data for the fractionation of edible oil mixtures by supercritical carbon dioxide. Good agreement was obtained between experimental and predicted results; moreover, the model correctly predicts the trends with different operating and design parameters.     

Synergistic Extraction of Lanthanides in a Liquid-Liquid Countercurrent Centrifugal Extractor

We have developed a liquid-liquid countercurrent centrifugal extractor that induces Taylor vortices in the annular fluid region. To demonstrate extraction of multiple species (Nd/Sm/Eu/Gd/Dy) with N,N,N′,N′-tetraoctyl diglycolamide (TODGA), additional chemical agents, such as a surfactant (sodium bis(2-ethylhexyl) sulfosuccinate (AOT)), a synergist (nonanoic acid) and a masking agent (N,N,N′,N′-tetraethyl-3,6-dioxaoctane-1,8-diamide (DOODA(C2))) were employed. When only TODGA was utilized, extraction performance was not effective due to the insufficient dispersion even under a high rotating speed. By combining TODGA and other chemical agents, the separation performance was improved considerably in the countercurrent flow of aqueous and organic phases due to the synergistic effect and improved dispersion.