模拟移动床色谱线性分离过程的建模和数值分析

本文采用能够真实反映模拟移动床色谱(SMB)周期性稳态的数学模型对线性分离过程进行数值模拟计算,分析过程参数变化对分离效果的影响。数值计算结果表明SMB分离过程中的操作变量对分离性能指标(纯度和收率)的影响是相互冲突的,进而指出了对SMB过程进行多目标优化的必要性。     

溶剂梯度模拟移动床分离奥美拉唑对映体的研究

模拟移动床一般在平衡模式下操作,即在模拟移动床（SMB）各区中采用相同的温度、压力和流动相组成等操作条件。但最新研究表明,在SMB各区适当使用梯度操作,如温度梯度、压力梯度、溶剂梯度等,优化各区操作条件,可以显著改善分离性能。本文测定了奥美拉唑对映体在乙醇／正己烷中的吸附平衡,根据SG—SMB平衡理论,确定了分离奥美拉唑对映体的完全分离区域,并以此为指导初步选择了分离条件,使R—OME和S—OME纯度分别达到95．11％和96．34％。     

木糖醇母液色谱分离性能优化

在实验室模拟移动床(SMB)分离设备上成功地实现了木糖醇母液中木糖和木糖醇组份的分离提纯。并在平衡理论的框架下,采用基于真实移动床(TMB)的简化数学模型,以产品纯度和收率为系统分离性能的优化指标,研究SMB分离性能与操作条件之间的关系。通过对木糖醇母液SMB色谱分离过程操作条件的寻优仿真研究,确定稳态时柱内的木糖和木糖醇浓度分布状态;计算出不同操作条件时两组分产品液各自的纯度和收率变化规律图。在阀门切换时间为15min,进料木糖醇母液中木糖浓度35gL-1,木糖醇浓度114gL-1,进料和出料总量恒定为16mLmin-1,循环洗脱剂流量恒定为18mLmin-1的操作条件下,木糖醇母液进料流量在1~2.3mLmin-1范围内都可同时获得纯净木糖醇与木糖产品。在实验室SMB分离设备上进行了验证,得到的木糖和木糖醇产品液纯度和收率均达到了100%,所有实验结果与仿真曲线基本吻合。因此采用基于TMB的简化的平衡理论模型进行仿真和优化研究可分析和预测木糖母液SMB色谱分离系统操作条件对系统分离性能的影响,有效地指导了产品分离实验、工业化放大设计和生产优化操作。     

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％。     

基于双种群算法的模拟移动床多目标操作优化

以有限元法求解模拟移动床的稳态TMB模型和动态SMB模型,提出基于Pareto非劣解集的多目标双种群遗传粒子群算法;利用动态SMB模型仿真模拟移动床色谱吸附分离过程,以分离纯度和性能指标分别作为约束条件和目标函数进行多目标操作优化设计.仿真结果表明,SMB模型较之TMB模型更真实可靠,双种群遗传粒子群算法也较单一种群的...     

移动床亲合色谱在分离果葡糖浆工业生产中的应用

利用20柱4区连续移动床亲合色谱对果葡糖浆进行分离的中试级生产试验。理论确定了进料液流量、提余液、提取液的流量、切换时间和洗脱剂流量、回流量等操作条件,考察了SMB分离性能的情况和在具体生产中的应用情况。通过试验确定了本套连续移动床色谱分离装置分离果葡糖浆的合适操作条件,在此操作条件下,提取液中果糖的纯度可以达到95%以上,完全可以用于工业化生产结晶果糖。     

浓缩硼-10模拟移动床色谱分离的放大研究

为实现SMB色谱分离硼-10的工业化,进行氯型硼特效树脂排代色谱法富集硼-10的SMB放大实验研究。放大研究中色谱柱的内径由原来的1.0 cm放大到8.5 cm,树脂也由原先的均匀小颗粒(平均为230μm)改为商用粒度范围颗粒(平均为780μm)。SMB放大色谱分离系统连续运行了约60 d(129次端口切换),取得富集度31.11%~40.31%的硼-10酸固体68 g。根据Fujii理论公式,对SMB放大分离系统中不同端口切换次数时的富集因子ε和理论踏板高度HETP进行计算,结果发现ε和HETP在整个实验过程中均保持常量,其值分别为ε=0.009 2±0.000 7,HETP=0.83±0.10 cm。与前期小型SMB分离系统的实验结果相比,ε变小,HETP变大,分离效果变差明显。     

二甲苯模拟移动床分离过程建模与仿真

模拟移动床（SMB）是混合二甲苯分离的重要技术。模拟移动床区域回流比是决定产品质量的关键参数。在真实移动床（TMB）建模方法基础上,结合实际工况数据,建立了模拟移动床吸附分离过程机理模型,并通过分析区域回流比对产品质量的影响,得到不同产品质量要求以及进料品质的情况下区域回流比的操作区间。仿真结果表明,TMB建模方法能较好地描述模拟移动床实际工况。基于机理模型对操作区间的分析结果可以为模拟移动床分离过程的工艺设计和操作提供指导意见。     

间歇模拟移动床色谱分离过程的建模与优化

间歇模拟移动床(I-SMB)的过程是多列色谱过程,它是对传统模拟移动床(SMB)技术的改进。在I-SMB过程中,将两个端口切换的时间间隔分为两个子时间间隔,产品只在第一个子时间间隔中被收集。介绍了间歇模拟移动床的基本原理,并采用色谱平衡理论的基础上实现两组分的分离。然后通过SMB与I-SMB的比较结果证明无论在线性吸附等温线还是在非线性吸附等温线条件下,I-SMB都能够比SMB实现更高的分离性能。     

微粒群算法在模拟移动床色谱分离过程优化中的应用

运用微粒群算法开发出一种非线性模拟移动床(SMB)色谱分离过程的优化策略.该优化策略将模拟移动床的最大吸附剂生产率作为优化问题的目标函数,采用模拟移动床的TMB模型来计算微粒群优化算法的适应值.采用该优化算法对手性化合物萘酚对映体(bi-naphthol)的模拟移动床色谱分离操作条件进行了优化,仿真结果表明了该优化策略的有效性.     

Use of two feeds in simulated moving beds for binary separations

Simulated moving bed (SMB) and Analog systems with two-feeds are proposed to increase the separation performance. Operation with both total and partial feeds is studied. When the two feeds have different compositions, the proposed SMB system often showed better performance than conventional SMB and Varicol systems and the Analog system with two-feeds typically achieved higher purities compared to the Analog for conventional SMB and Varicol when the number of tanks was increased. Partial-feed operation strategy for SMB and Analog systems with two-feeds often showed significant performance improvement compared to conventional SMB plus partial feed and Varicol plus partial feed. When the two feeds are identical, partial feed operation of the two-feed SMB becomes identical to partial feed operation of Varicol.     

Improved performance of simulated moving bed process using column‐modified feed

A “FeedCol” strategy was developed to improve separation performance in simulated moving bed (SMB) processes. In the FeedCol operation, a short chromatographic column was simply added to the SMB unit and feed was supplied by a pulse input through the column to the SMB process. Because the feed was made in the shape of partially separated chromatographic peaks through the column, the purities in the raffinate and extract products were improved efficiently in the SMB process. All the performance parameters for a binary mixture with low selectivity (α = 1.1) were better for the FeedCol operation than for the conventional SMB operation (2‐2‐2‐2). Because the feed injection through the feed column was synchronized with the SMB process during the switching period, two new operating variables were introduced: injection length and injection time. Their effects on the suggested strategy were evaluated in terms of performance parameters through a detailed simulation study. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

Chiral Separation of R,S‐α‐Tetralol by Simulated Moving Bed

Abstract

This work deals with chiral separation by Simulated Moving Bed (SMB) chromatography. A simulation package is used to predict the effect of the operating variables on the process performance. The “separation volume” methodology is used to study effect of the presence of mass transfer resistances presented by different particle sizes on operating conditions of the SMB unit with emphasis to the net flow in zone I and IV in terms of interstitial velocity ratio (γ₁ and γ₄). The experimental operation of the a pilot plant SMB unit LICOSEP 12–26 (Novasep, France) is carried out for the separation of enantiomers of R,S‐α‐Tetralol using the chiral adsorbent CHIRALPAK AD with particle size 20 µm. To obtain real insight to operation of the SB unit Licosep 12–26 the mathematical model accounts for all dead volumes inside of the SMB unit and time delay in shifting of injection and withdrawal points. Experimental and theoretical results based on the SMB model are compared in terms of process performance parameters and internal concentration profiles.     

Micro-simulated moving bed (μSMB) systems: A numerical study

Continuous chromatographic separation processes like simulated moving bed (SMB) systems have been employed in petrochemicals, sugar, and more recently, in pharmaceutical industries by virtue of their superior separation efficiency. Miniaturization of chromatography-based analytical techniques (e.g., high performance liquid chromatography, micro-HPLC or μHPLC) has already been successfully demonstrated in the last few years owing to the rapid development in MEMS technology. With such a rapid progress in technology, it is definitely possible to realize the miniaturization of a powerful continuous chromatographic process such as SMB. Micro-SMB (μSMB) systems could not only inherit the merits of μHPLC, but also provide efficient separation of compounds such as isomers and enantiomers that are otherwise very difficult to isolate. In this paper, new simulations of the performance of a μSMB system for the separation of a mixture of phenol and o-cresol, using a robust numerical algorithm developed that mimics the dynamic operation of the μSMB system, are presented. A systematic parametric sensitivity analysis that addresses the effects of various process parameters on the performance of the μSMB system is also presented. High purities and yields of both phenol and o-cresol is achieved in the μSMB by judicious choice of process parameters.     

Comparative Analysis of Single‐Cascade Five‐Zone and Two‐Zone SMB Systems for the Separation of a Ternary Amino Acid Mixture

A ternary separation usually requires the use of two simulated moving bed (SMB) units in series. Since an increase in the number of SMB units leads to a significant increase in capital and operational costs, the use of a single SMB unit is preferred if its structure can be modified to treat a ternary separation. Such a modified single SMB unit has been typified by a five‐zone SMB or a two‐zone SMB so far. The separation performances‐of a five‐zone SMB and a two‐zone SMB are compared in this paper by using the ternary amino acid mixture as a model system. A five‐zone SMB is designed with the safety margin method while a two‐zone SMB is optimized using genetic algorithm. A five‐zone SMB based on the maximum allowable safety margin, although it may not guarantee the global optimum solution, results in much better separation performance than a two‐zone SMB at its global optimum state.     

Nonlinear model-based repetitive control of simulated moving bed process

The simulated moving bed (SMB) process, after more than 40 years of successful operation in the petro-chemical industry, has emerged as one of the most important separation processes in the pharmaceutical, fine chemical, and biotechnology fields. However, optimal operation and automatic control of the SMB process is still challenging because of its complex dynamics caused by periodic port switching and inherent nonlinearity. In this research, a novel advanced control technique for the SMB process has been proposed. In the proposed technique, regulation of both extract and raffinate purities measured at the terminal time of each switching period is performed by a nonlinear repetitive controller which utilizes the past period data as feedback information. The repetitive controller was designed on the basis of a fundamental nonlinear model of the SMB process. Through application to a numerical SMB process, it was found that the proposed control technique performs quite satisfactorily against model error as well as set point and disturbance changes.     

模拟移动床色谱拆分D-塔格糖和D-半乳糖的模拟研究

模拟移动床色谱操作参数的模拟和优化对实际分离生产具有重要的指导意义。本文采用平衡扩散模型,对模拟移动床色谱分离D-塔格糖和D-半乳糖进行了模拟研究,根据三角形理论确定了其最佳操作参数,并考察了各区柱数配置、切换时间和分离区流量等变化对分离效果的影响,验证了模拟移动床操作参数的敏感性和模型建立的必要性。     

模拟移动床改进进料模式提高生产效率的模型化研究(英文)

A new feeding mode for a simulated moving bed(SMB)is proposed.The outlet stream from zone Ⅱ is collected at regular intervals.The concentration of the solution is increased by dissolving raw materials and then fed to zone Ⅲ as the feed stream during the next collection interval. In this feeding mode,the concentration of the stream fed to zone Ⅲ is identical to that of original feed,while in a conventional SMB,the feed is diluted by mixing with the outlet stream of zone Ⅱ before feeding to zone Ⅲ.The new feeding mode increases the inlet concentra tion of zone Ⅲ.A modeling investigation shows that higher inlet concentration of zone Ⅲ increases the height of concentration band in SMB,improving the separation performance significantly.In comparison with the traditonal feeding mode,the new feeding mode increases the productivity by 23.52% and decreases the solvent consumption by 22.56%,so as to increase the raffinate and extract concentrations by 53.17% and 20.38%,respectively.The collection interval for the outlet stream from zone Ⅱ has no effect on the separation performance after reaching the steady state,so that the collection interval can be increased to make the operation more convenient.