大型液相色谱分离过程FAD－SMT数学模型及其数值解

提出大型液相色谱分离过程ＦＡＤ－ＳＭＴ数学模型，把色谱分离连续性方程转变为对流扩散方程和常微分方程组，并提出模型的数值方法，分析了数值解的稳定条件和收敛条件以及空间和时间步长的选取。实验结果表明，ＦＡＤ－ＳＭＴ数学模型计算的液相色谱分离葡萄糖、果糖和分离甘露醇、山梨醇理论与实验流出曲线相吻合。灵敏度分析结果表明：相平衡常数比轴向扩散系数和总传质系数对色谱分离有较大的影响。     

大型液相色谱分离过程FAD－SMT数学模型及其数值解

 提出大型液相色谱分离过程ＦＡＤ－ＳＭＴ数学模型，把色谱分离连续性方程转变为对流扩散方程和常微分方程组，并提出模型的数值方法，分析了数值解的稳定条件和收敛条件以及空间和时间步长的选取。实验结果表明，ＦＡＤ－ＳＭＴ数学模型计算的液相色谱分离葡萄糖、果糖和分离甘露醇、山梨醇理论与实验流出曲线相吻合。灵敏度分析结果表明：相平衡常数比轴向扩散系数和总传质系数对色谱分离有较大的影响。     

吸附剂性能和操作参数对液相色谱流出峰不对称性的影响

色谱流出峰的拖尾现象普遍存在于制备和大型色谱分离过程中,它直接影响分离的产率和回收率．本文提出采用色谱流出峰形的不对称偏差度来表征色谱流出峰的拖尾程度;并基于液相制备色谱分离过程FAD－SMT模型及吸附速率理论,通过计算机模拟,定量分析了吸附剂性能和操作参数对色谱流出峰形不对称性的影响。结果表明：不仅是吸附剂的热力学和动力学性能（包括吸附相平衡关系、液固两相间的传质阻力）;而且柱的设计和吸附剂的装填状况（包括轴向扩散系数）,以及色谱分离的操作条件（进料时间、浓度和流速等）都直接影响色谱流出峰形的不对称性。随着吸附相平衡等温线的非线性程度增大,或者总传质系数的减小,色谱流出峰形的不对称偏差度明显增大;吸附剂吸附容量的减小也将引起色谱流出峰形的不对称偏差度的增加;色谱流出峰形的不对称偏差度与进科体积、浓度和流体线速,以及轴向扩散系数的增大成正比。     

吸附剂性能和操作参数对流相色谱流出峰不对称性的影响

色谱流出峰的拖展现象普遍存在于制备和大型色谱分离过程中,它直接影响分离的产率和回收率。本文提出采用色谱流出峰形的不对称偏差度来表征色谱流出峰的拖尾程度,并基于液相色制备色谱分离过程ＦＡＤ－ＳＭＴ模型及吸附速率计算机模拟,定量分析了吸附剂性能和操作参数对色谱流出峰形不对称性的影响。     

大型液相色谱分离甘露醇和山梨醇的热力学及动力学参数辨识

本文研究了液相色谱分离过程的吸附平衡常数、传质系数参数的估值模型，用色谱技术和以惰性物示踪的扰动应答实验技术测定甘露醇和山梨醇在钙型吸附剂上的吸附相平衡常数和总传质系数以及床层中的轴向扩展系数，结果表明：吸附平衡常数和吸附剂的选择性随温度的升高而下降；液固相间的总传质系数随温度的升高而增大；轴向扩散系数随流速的增大而增大，参数灵敏度分析的结果表明，相平衡关系，尤其是吸附选择性，对色谱分离的影响有较     

液相色谱技术测定葡萄糖果糖在Ca型吸附剂上相平衡常数和总传质系数

]考虑轴向扩散的影响,导出液相色谱技术测定吸附相平衡常数和总数传质系数参数估值模型,测定葡萄糖果糖吸附相平衡常数和总传质系数,研究流速、温度对这些参数的影响。获得理论计算与色谱分离实验流出曲线相吻合结果。     

液相制备吸附色谱流出峰对称性的若干影响因素

在色谱分离连续性方程和质量传递速率方程基础上,对色谱分离过程进行计算机模拟,定量分析了分离体系的热力学、动力学参数和操作条件对色谱流出峰形对称性的影响。结果表明,吸附相平衡关系、液固两相间的传质阻力及进料体积、进料浓度和流体线速等都将直接影响色谱流出峰形的对称性。流出峰形的不对称程度随着吸附等温线的非线性程度、液固两相间的传质阻力、流体线速、进料体积、进料浓度的增大而增大;在线性条件下,随着吸附剂吸附容量的减小而增大。     

大型工业液相色谱分离山梨醇和甘露醇过程优化研究

本文采用非线性非平衡含轴向扩散色谱数学模型模拟山梨醇-甘露醇同分异构体系大型工业液相色谱分离过程。首先，通过对分离过程进行参数灵敏度分析，确定了被优参数为进料浓度和色谱柱柱长；然后，以山梨醇的产率为目标函数，限定山梨醇的产品纯度和最小回收率，利用改进的单纯形法对分离过程进行两参数优化，分析了不同进料量和流体线速对最优条件的影响。结果表明：进料量和流体线速对回收率和最大产率的影响程度与参数灵敏度分析结果基本一致，从而证明了利用参数灵敏度分析方法选择色谱分离过程被优参数的可行性。本文还对改进的单纯形法寻优过程进行了探讨，构造了单纯形法优化大型液相色谱的基本方法和框图。     

非线性多相催化动态模型的理论分析

本文讨论了吸附为非线性的多相催化的动态模型,用特征线方法对该模型进行了分析,求得了流出曲线的解析结果,指出了非线性对多相催化动态测量结果的影响,为速率参数及吸附参数在非线性条件下的动态测定给出了计算公式。     

双柱交替循环色谱分离甘露醇山梨醇过程

本文在非线性非平衡双柱循环色谱分离过程数学模型的基础上,进行了双柱交替循环色谱分离甘露醇山梨醇的实验,对模型进行了实验验证。结果表明：采用非线性非平衡双柱循环色谱模型计算的流出曲线与实验结果相吻合。计算机模拟的结果从理论上证明了对本实验体系采用双柱交替循环色谱分离模式比采用传统的色谱分离模式能获得更高的分离产率,产率随循环次数的增加而增加,使用双柱交替循环色谱分离操作模式获得的分离效率超过使用传统长色谱柱操作模式获得的分离效率。当轴向扩散比较严重、液固两相间的传质阻力较大,或者吸附的表观选择性系数较小时,采用双柱循环色谱模式比使用传统单柱色谱模式能获得更高的产率。     

SYSTEM IDENTIFICATION METHOD OF LINEAR AND NON-LINEAR LIQUID PREPARATIVECHROMATOGRAPHIC SEPARATION

1.INTRODUCTIONThechromatographicproblemistorelatetheconcentrationprofileofthebandattheoutletofthecolumntotheequilibriumisothelm,themasstransferkineticsandtheprofileoftheinjectionbandandperformtheoptimumdesignofseparationprocess['J.Togettheobjective,Itisnecessarytoidentifythesystemof.ProjectsupPOrtedbyTheNationalNaturalScienceFoundationofChinatheliquidadsorptionchromatographylinearornon-linear,andthendeterminethethermodynamicanddynamicsparametersofthesystemaccuratelysothatthecomputersim…     

A FAD-SMT Model of Large Scale Liquid Adsorption Chromatography

The paper proposes a FAD-SMT model of large-scale liquid chromatography by which a continuous equation of chromatographic separation is decomposed into a convection dispersion partial differential equation and a set of ordinary differential equations. The numerical method for the FAD-SMT model is established. The stability and the convergence condition of numerical solution, and the choice of time and space interval are discussed. The FAD-SMT model is used to simulate liquid adsorption chromatography and cycling adsorption chromatography. Results show that the elution curves calculated by FAD-SMT model are good agreement with the experimental elution curves of the separation of glucose and fructose, the separation of sucrose and reducing sugar and the separation of mannitol and sorbitol. The result of parameter sensitivity analysis shows that the chromatographic elution curves are more sensitive to the changes of the parameter ai in Langmuir isotherms than to the changes of other parameters in the studied system.     

DETERMINATION OF THERMODYNAMIC AND KINETIC PARAMETERS OF LARGE SCALE CHROMATOGRAPHIC SEPARATION OF SUGAR AND REDUCING SUGAR

The parameter identification model of large scale chromatography separation process is proposed.The phase equilibrium constants and lumped mass transfer coefficients of sugar and reducing sugar adsorption on D1,D2 and D3 resins as well as the axial dispersion coefficients of the fluid through packed columns are determined by means of the pulse-response experiment technique with an inert substance as a tracer and the chromatography measuring technique.The elution curve calculated from these parameters is good agreement with the experimental elution curve.The sensitivity analysis of these parameters is carried out ,and the result shows that the elution curves of chromatography separation are more sensitive to the variations of the phase equilibrium relationship than to the variation of the axial dispersion as well as the lumped mass transfer coefficients.     

DETERMINATION OF THERMODYNAMIC AND KINETIC PARAMETERS OF LARGE SCALE CHROMATOGRAPHIC SEPARATION OF SUGAR AND REDUCING SUGAR

ＤＥＴＥＲＭＩＮＡＴＩＯＮＯＦＴＨＥＲＭＯＤＹＮＡＭＩＣＡＮＤＫＩＮＥＴＩＣＰＡＲＡＭＥＴＥＲＳＯＦＬＡＲＧＥＳＣＡＬＥＣＨＲＯＭＡＴＯＧＲＡＰＨＩＣＳＥＰＡＲＡＴＩＯＮＯＦＳＵＧＡＲＡＮＤＲＥＤＵＣＩＮＧＳＵＧＡＲＬｉＺｈｏｎｇ；ＳｈｕＷｅｎｌｉ；...     

THE DETERMINATION OF ADSORPTION ISOTHERMS AND SOLID DIFFUSION COEFFICIENTS OF MANNITOL AND SORBITOL BY LIQUID CHROMATOGRAPHY TECHNIQUE

The parameter identification model is proposed for determining the linear adsorption isotherms and the solid diffusion coefficients by using adsorption chromatorgaphy.Axial dispersion coefficients is firstly determined by pulse-respond experiment technique with an inert substance as tracer,then the elution curves of chromatography separating the isomer mannitol and sorbitol are determined by the chromatographic measuring technique,and pinally the adsorption isotherms and the solid diffusion coefficients of mannitol and sorbitol on Ca^2+ resins are estimated by using this model.The results show that the axial dispersion coefficients increase with fluid velocity increasing,The adsorption equilibrium constants decrease with temperature rising;and the solid diffusion coefficients increase with temperature rising.The theoretical elution curves are good agreement with the experimental elution curves of the liquid adsorption chromatography separating the mannitol and the sorbitol.The model provides a simple and reliable procedure to estimate the kinetic and thermodynamic parmeters of the adsorption.     

THE DETERMINATION OF ADSORPTION ISOTHERMS AND SOLID DEFFUSION COEFFICIENTS OF MANNITOL AND SORBITOL BY LIQUIDCHROMATOGRAPHY TECHNIQUE

1INTRODUCTIONTheseparationprocessoflarge-scaleliquidchromatographyisaunstabletransferprocess.Theseparationefficiencyisaffecteddirectlybytheadsorptionisotherms,themasstransferresistancewithinsolidadsorbentparticleandtheoperationparametersinthesystem.Therefore,thedeterminationoftheisothermsandisnecessaryfordesigningandoptimizingthechromatographicprocess.Thereareseveralmethodstodeterminekineticparameters.Carl(1992)carriedoutthekineticexperimentoftheadsorptioninacontinuousstirredtankadsorberl…     

梯度洗脱优化-离子色谱-脉冲安培法分析婴幼儿配方乳粉中的糖和糖醇

建立了梯度洗脱优化-离子色谱-脉冲安培检测技术分析婴幼儿配方乳粉中麦芽糖醇、半乳糖、葡萄糖、蔗糖、果糖、乳糖6种与代谢疾病紧密相关的糖和糖醇的方法。该方法对样品的前处理、色谱柱的选择、淋洗液的梯度等色谱条件进行了优化,重点研究了淋洗液梯度对各组分分离效果的影响。将梯度洗脱程序分解为弱保留组分分离、乳糖分离、基质消除、系统平衡4个子程序,并分别对其进行了条件优化,实现了6种组分的完全分离,并有效解决了弱保留组分色谱峰易重叠、乳糖色谱峰易拖尾等现象。6种组分的线性范围为0.5~100 mg/L,相关系数（r）>0.99,方法的检出限（S/N=3）为0.06~0.40 mg/L。该方法具有分离度好、灵敏度高等优点,可满足例行分析的要求,同时也为淋洗液的梯度优化提供了可借鉴的方法。