Separation of Lens culinaris Hemagglutinin by Forced Flow Electrophoresis

Abstract

The usefulness and versatility of forced flow electrophoresis (FFE) for the separation of proteins were examined with Lens culinaris hemagglutinin (lentil lectins). FFE was operated both in the usual single stage and in a more effective, new double-stage scheme. The dependence of the resolution on the flow velocity through the permeable channel and on the electrical field were analyzed. Increased effectiveness in separation was obtained with various pretreatments such as electrofiltration, dialysis, and centrifugation.     

A New Continuous Flow Reactor for Simultaneous Reaction and Separation

Abstract

The acid catalysed hydrolysis of methylformate has been investigated in a continuous flow annular reactor packed with activated charcoal, and equipped with a rotating feed injection port. Chromatographic separation of the products, formic acid and methanol, effectively suppressed the reverse reaction, causing conversions to be significantly greater than the thermodynamic equilibrium conversions that would have been obtained in the absence of separation. Comparisons of numerically simulated reactor performance with experimental results showed good agreement, although some differences occurred as experimentation proceeded, most probably due to deactivation of the activated charcoal.     

Novel Gas-assisted Three-liquid-phase Extraction System for Simultaneous Separation and Concentration of Anthraquinones in Herbal Extract

abstract Gas-assisted three-liquid-phase extraction (GATE), which has the advantages of both three-liquid-phase extrac-tion and solvent sublation, is a novel separation technique for separation and con...     

周期全回流间歇精馏中全采出操作时的塔顶浓度平台期(英文)

The total withdrawal operation is an inevitable section in cyclic total reflux batch distillation.In the operation,an interesting phenomenon "overhead concentration platform"(OCP) appears,which is defined as a period of time with high overhead concentrations when the operation is changed from total reflux to total withdrawal.The OCP phenomenon and its influential factors,such as the theoretical stage number,feed concentration,and feed composition,are examined by simulations and experiments.The experimental equipment is a column with random packings.It is shown that the number of theoretical stages influences the OCP more significantly than the other factors.     

Fluid Flow Characteristics of Forced Flow Electrophoresis

Abstract

Fluid flow in forced flow electrophoresis has not been previously analyzed, even though it presents some interesting aspects. The effectiveness of this method for biological separations is due to a superimposition of an electric field on filtration. A mathematical model is presented, describing fluid flow and mass transfer for dilute solutions at electrical potentials less than the critical one. The calculated solute trajectories in a channel are determined by the ratio of the electrophoretic velocity to the withdrawal velocity through the permeable wall. The stationary layer and the layer in which all the solutes arrive at the permeable membrane at the end of the channel are also calculated. The concentration of the filtrate through the permeable membrane is obtained from the material balance of the solute entering the channel. Increased performance is obtained by means of a double-stage forced flow electrophoresis, where the ratio of final filtered solute concentration to inlet concentration is shown to be the square of the same ratio at the first stage.     

含聚浓度对旋流器流场分布和分离性能的影响

基于计算流体动力学软件Fluent,采用非牛顿流体黏度模型、雷诺应力模型和离散相模型对不同含聚浓度下旋流器内的黏度场进行研究。发现随着含聚浓度的增加,表观黏度受剪切速度影响越大,流体所呈现的非牛顿特性也越强,利用分级效率计算旋流器内不同粒径油滴的分离效率与总效率,并将高浓度含聚水溶液呈现的不同粒径的分离效率的规律应用于低浓度范围,结果表明,高含聚浓度水溶液的拟合方程可作为同一粒径下不同含聚浓度的经验公式。     

高硫高酸油对催化分馏顶循线的影响及对策

针对催化分馏塔塔顶循环回流线短时间减薄的特殊情况，从腐蚀学原理出发，对回流线所处工况及腐蚀产物进行了分析，指出顶循线腐蚀主要是由HCL—H2S—H2O引起的，并提出了一些有效措施。     

Growth of Colloidal Particles in an Electrokinetic Separation Technique

Abstract

The growth of colloidal particles of alumina in an aqueous suspension as it passes through an electric field is investigated. It is shown that the particle growth depends on the time the colloidal particle spends in the electrical field and is independent of the flow of the suspension. The relevance of this effect in the clarification of liquids without any additives is pointed out.     

表面原位聚合法荷正电纳滤分离层的构建及分离性能的研究

以聚氯乙烯(PVC)中空纤维超滤膜为支撑层,甲基丙烯酰氧乙基三甲基氯化铵(DMC)为荷正电单体,聚乙二醇双丙烯酸酯(PEGDA)为交联单体,通过表面原位聚合的方法,制备得到了荷正电PVC中空纤维复合纳滤膜。考察了DMC与PEGDA比例对复合纳滤膜渗透和截留性质的影响。结果表明,调控两种单体的比例可以有效地调节膜的渗透分离性能。随着DMC含量的增加,膜表面亲水性与通量增加,对小分子染料结晶紫的截留率下降,对维多利亚蓝B的截留率则始终保持在99%以上,而对氯化钠等无机盐类始终没有截留能力。当DMC与PEGDA比例为9:1时,复合纳滤膜在0.3 MPa下,纯水通量为78.6 L?m-2?h-1,对维多利亚蓝B的截留率高达99.9%,对结晶紫的截留率仅为1.9%,对氯化钠的截留率为零,表明该膜可以用于小分子有机染料的高效分离以及盐溶液中小分子有机染料的脱除。     

The Sizes of Polymer Molecules and the GPC Separation

Abstract

This introductory review explains in simplest terms the separation mechanism in GPC and the concept of size as its discriminant. Sample molecules permeate the gel to different degrees depending on their size and are kept out of the solvent stream in the interstices in correspondingly different time ratios. For rigid molecules the size is determined either by the volume or by the most prominent linear dimension. A better approximation seems to be Giddings's “mean external length.”

With polymers the decisive size parameter is the hydrodynamic volume. Its calculation from molecular weight must take into account the coiling of the polymer, its flexibility, and its interaction with the solvent. Another important consideration is the statistical nature of polymer properties which results in average values for molecular weight and size. Chain statistics yield polymer sizes that are compatible with pore dimensions of appropriate gels.     

木糖与木糖醇色谱分离操作的质量优化

利用模拟移动床（SMB）连续色谱技术分离木糖醇母液中的木糖和木糖醇组分。在平衡理论的框架下，提出了使用基于相应的真实移动床（TMB）的简化数学模型，来研究各进料液和产品流出液的流量等操作参数的变化，对SMB分离性能（以纯度和收率作为性能指标）影响的方法。采用本方法进行了操作条件寻优仿真，并取得满意结果。在实验室SMB分离设备上，基于此最佳操作条件所得到的木糖和木糖醇产品液纯度和收率均达到100％。     

循环全回流间歇精馏控制方法的试验研究

提出了采用塔顶和塔中温度控制进行操作状态转换的循环全回流间歇精馏控制方法,并以异丙醇-正丙醇为试验物系进行了试验研究。结果表明,用塔顶和塔中温度控制动态累积全回流-全采出的状态切换是完全可行的。此外,引入塔中温度控制使产品数量、质量及操作时间优于单独用塔顶温度控制,并且双温度控制操作弹性更高。     

短程蒸馏分离效果评价因子研究

针对短程蒸馏分离效果评价,从馏出物中轻组分分率与残余物中重组分分率乘积最大化的分离目标出发,建立了评价短程蒸馏分离效果的分离因子;进而考虑短程蒸馏实际操作工况,确定了该分离因子的变化区间,并由此绘制了分离因子变化区域图。分析表明,该分离因子反映了原料液组成、馏出物得率及其中轻组分分率三者的综合影响,能有效表征短程蒸馏分离效果;根据分离因子变化区域图,可明确短程蒸馏操作工况与理想分离条件的接近程度,为评估提高分离效果的可能性和采取可行优化操作条件提供指导;论文最后通过二元混合液短程蒸馏分离实验,进一步表明了该分离因子对短程蒸馏操作条件优化具有实际指导价值。     

Evaluation of Micellar Electrokinetic Capillary Chromatography for the Separation and Detection of Normal and Modified Deoxyribonucleosides and Deoxyribonucleotides

Abstract

Micellar electrokinetic capillary chromatography allows high resolution separations with very small sample volume requirements. Deoxyribonucleotide oligomers can be resolved on the basis of chain length, nucleic base sequence, and base modification. Sensitivity for dideoxyribonucleosides in the -presence of a 1,000-fold excess of deoxyribonucleosides is ca. 12 pg with on-column UV absorbance detection.     

Sedimentation of Charged Fibers From a Two-Dimensional Channel Flow

An analysis is presented to describe the motion of a charge-carrying fiber under gravity in a laminar flow, between two horizontal conducting parallel plates. Using the method of limiting trajectories, the precipitation efficiency of a uniform aerosol that enters the channel is determined for both insulating and conducting fibers.     

乙醇－水－甲醇精馏过程中温度和组分浓度沿塔高的分布

本文用全回流筛板精馏塔测定了四个压力下的乙醇－水和乙醇－水－甲醇两个物系沿塔高温度与浓度的分布。用两元实测结果计算了不同压力下各板的默弗里板效，并以ＵＮＩＦＡＣ活度系数方程和维里状态方程为基础的热力学模型建立了精馏计算模型。用该模型对三元体系进行了计算，与实测结果符合良好。     

化工专用空分装置的安全运行管理探讨

在实际建设和发展过程中,绝大多数的气化炉都使用煤为基础性的燃料,同时还使用氧气作为主要的气化剂。我国工业建设和发展的过程中,需要大力推动化工工业的发展,并在此过程中不断对其应有的油气工程产业进行完善,使得其逐渐向着煤炭方面进行发展。在这种状况下,就能够促进我国现代化化工产业的发展,并加强化工产业的转型,以促进其配套生产的空分装置在一定程度上得到转型。在逐渐发展的过程中对空分装置的研究,以及其安全运行过程中的管理措施就成为化工行业乃至整体工业领域关注的重点问题之一。     

氢回收膜分离装置的优化操作

针对二级中空纤维分离装置回收氢气浓度较低的问题,优化压力、温度、空速等操作参数,可将回收氢气的浓度提高4%～5%,每年可增加收益40万元。     

强制气流作用下溶液蒸发过程的传质规律

针对强制气流作用下溶液的蒸发过程,在分析气液相间力学特性的基础上,根据Levich涡流衰减理论和边界层理论,将气流流动状态与相间传质结合,研究了湍流气流横掠液面过程中气液相间的传质变化规律,分析了雷诺数、气流流道结构及普朗特混合长度对传质的影响,得到了气液相间的湍流质扩散系数的变化规律,湍流气流横掠液面条件下的对流传质准则数Sh=0.221Sc1/3Rex1/2. 结果表明,湍流扩散系数、传质系数与气流的流动状态密切相关,气流流道结构对气液相间的传质有重要影响.     

Surface Force-Pore Flow Model in Predicting Separation and Concentration of Polyhydric Alcohols in Aqueous Solutions Using Cellulose Acetate Membranes

Abstract

The reverse osmosis separation and concentration of polyhydric alcohols were experimentally tested by using cellulose acetate membranes of different average pore sizes. An attempt was made to predict membrane performance data, such as the solute separation and the product permeation rate, on the basis of the surface force-pore flow model, and the results were tested by experimental values. The processing capacities of the membranes were also calculated.