This dissertation presents an analysis of two aspects of the chromatographic separation process known as Simulated Moving Bed (SMB) chromatography. The first aspect is system design, and the second is improving computer simulations to generate heuristics for choosing operational modes. For the past 15-20 years, there has been a surge of interest in the use of Simulated Moving Bed systems for the chromatographic separation of chemicals¹. A wide variety of methods, nomenclatures, and conventions have been adopted over the years²⁻⁴, as teams from different backgrounds adopt and improve on the SMB technology. This work presents a unifying discussion of the two major design methods, Triangle Theory and Standing Wave Design, used in the SMB field. We provide the complete computer code required to execute both design methods. A sample problem is worked, which demonstrates the novelty and ease of use that such tools provide. Mathematica was chosen for the implementation of these design methods, because of its strong symbolic analysis capabilities, and simplicity of creating interfaces for new users. We present derivations of the classic Langmuir results in Mathematica, and proceed to extend those implementations. When analytic solutions are impossible, we use Mathematica's numerical methods. This work also develops a distributed computing tool known as ChromRunner which allows large numbers of detailed numerical simulations to be run simultaneously. The motivations and benefits of this approach are discussed alongside implementation details. We apply the distributed computing system to two separate SMB separations in order to optimize them, as well as determine heuristics governing their operational modes. We wrote ChromRunner in C#, and took advantage of Visual Studio's Entity Framework to create the database backend. The user interface for this software was created using Microsoft's "Windows Presentation Foundation" (WPF) technologies. / Ph. D.

The cost of pretreatment process for saccharification from biomass and the cost of dilute ethanol purification are significant components of the overall cost for fuel grade ethanol production through fermentation or other biological routes. This work focuses on developing optimal designs of dilute ethanol purification process and the new acid hydrolysis technology for the production of fermentable sugars from biomass where the overarching goal is to reduce the cost of ethanol production from biomass. In this thesis, the ethanol separation process with the reverse osmosis membrane pretreatment is developed to reduce separation cost and energy consumption especially when the feed is dilute. In addition, the new solid phase reactive separation system for biomass saccharification via acid hydrolysis is proposed. This new process is applied for both dilute and concentrated acid hydrolysis where the goal is to increase sugar yield and to reduce byproduct formation. The reaction kinetics of the concentrated acid hydrolysis is investigated through batch experiment. All of these use optimization approaches for seeking the best process designs and for parameter estimations.

S'han creat les eines necessàries per a estudiar la viabilitat de dur a terme la separació de mescles de dos i tres components basats en un mètode de separació en continu tipus SMB. Amb aquesta finalitat, s'ha creat un sistema per al disseny ràpid i econòmic de separadors SMB que permet simular el comportament d'una columna qualsevol integrada en un sistema SMB. Aquest sistema, està constituït per una sola columna cromatogràfica que pot treballar en qualsevol de les quatre zones en què es pot dividir un SMB.El sistema de control de l'instrument permet simular cicles complets de separadors SMB. A més, el programa també permet treballar amb separacions formalment binàries o ternàries, en conformacions de SMB de 4, 6 i 8 columnes i combinació d'elles agrupades en 4 zones de treball. El sistema també integra un programa de simulació numèrica i optimització de separadors SMB. La combinació del programa i el sistema de disseny de SMB permet establir la variació de la concentració de cada substància amb el temps podent així determinar: el nombre de columnes per zona, el temps de canvi de cada columna, el cabal d'operació a cada zona i la concentració de cada substància per cada sortida de l'SMB.Per tal de verificar el correcte funcionament de l'equip complet s'ha dut a terme la separació de dos components, fenol i triclorofenol, determinant-ne les condicions òptimes de separació. Tot i que la retenció entre aquestes dues substàncies és molt similar, el prototipus ha permès estudiar el comportament de la unitat SMB complerta. També s'ha estudiat la separació del p-aminofenol i l'o-aminofenol com a part integrant del procés de fabricació del paracetamol i se n'han trobat les condicions òptimes d'operació. En treballar amb aquest procés s'ha buscat la màxima puresa del p-aminofenol en detriment de la puresa de l'o-aminofenol aconseguint una puresa de p-aminofenol a la sortida refinat del 97%. Finalment, i des del punt de vista del canvi d'escala, s'han determinat els valors de la longitud no utilitzada de rebliment i del coeficient global de transferència de matèria per tal de poder extrapolar els resultats del prototipus a escala industrial. / Se han creado las herramientas necesarias para estudiar la viabilidad de desarrollar separaciones de mezclas de 2 y 3 componentes basados en un método de separación en continuo tipo SMB. Con esta finalidad se ha creado un sistema para el diseño rápido y económico de separadores SMB que permite simular el comportamiento de una columna cualquiera integrada en un sistema SMB. Este sistema está constituido por una única columna cromatográfica que puede trabajar en cualquiera de las cuatro zonas en que se puede dividir un SMB.El sistema de control del instrumento permite simular ciclos completos de separadores SMB. Además, el programa también permite trabajar con separaciones formalmente binarias o ternarias, en conformaciones de SMB de 4, 6 y 8 columnas y combinación de ellas agrupadas en 4 zonas de trabajo. El sistema también integra un programa de simulación numérica y optimización de separadores SMB. La combinación del programa y el sistema de diseño de SMB permite establecer la variación de la concentración de cada sustancia con el tiempo pudiendo así determinar: el número de columnas por zona, el tiempo de cambio de cada columna, el caudal de operación en cada zona y la concentración de cada sustancia por cada salida del SMB. Para verificar el correcto funcionamiento del equipo completo se ha separado una mezcla de dos compuestos, fenol y triclorofenol, determinando las condiciones óptimas de separación. Aunque la retención entre estas dos sustancias es muy similar, el prototipo ha permitido estudiar el comportamiento de la unidad SMB completa. También se ha estudiado la separación del p-aminofenol y el o-aminofenol como parte integrante del proceso de fabricación del paracetamol y se han determinado las condiciones óptimas de operación. Al trabajar con este proceso se ha buscado la máxima pureza del p-aminofenol con menoscabo de la pureza del o-aminofenol consiguiendo una pureza de p-aminofenol a la salida de refinado del 97%. Finalmente se han determinado los valores de la longitud de lecho no utilizada y del coeficiente global de transferencia de materia para extrapolar los resultados del prototipo a escala industrial. / The necessary tools to study the viability of developing separations of mixtures of 2 and 3 components using a continuous method like the SMB have been developed. A fast and non-expensive system to design such separations has been developed. This system can simulate the behaviour of a single column integrated in the SMB. This system is composed by a single column capable to work in every one of the four zones into which an SMB can be divided. The control system gives the possibility of simulate complete cycles of an SMB separator. In addition the program also can work with binary or ternary separations, in SMB conformations of 4, 6 and 8 columns and its combinations grouped together in 4 working zones. The system also integrates a numerical simulation and optimization program of SMB separators. The combination of program and SMB design system establishes the concentration of each substance within the time. It gives the following parameters: the number of columns per zone, the column switch time, the flow in each zone and the concentration at the SMB outlet. In order to check the correct operation of the whole unit the separation of phenol and trichlorophenol have been done determining the best operation conditions. However the retention of this substances is very similar, the prototype has studied the complete separation. It also has been studied the separation of p-aminophenol and o-aminophenol as a part of the sysntesis process os paracetamole and the best separation condition have been stablished. While working with this process the maximum purity of p-aminophenol has been searched. The purity of p-aminophenol at the raffinate outlet is about 97%. Finally the values of unused bed lenght and overall mass transfer coefficient have been calculated to extrapolate the results to the industrial scale.

Modèle monodimensionnel de type Piston-Dispersion. Le terme de dispersion axiale englobe alors toutes les imperfections de l'écoulement : injection des fluides non homogène dans l’espace et étalée dans le temps, effet de parois, et enfin volumes morts derrière les obstacles noyés dans le tamis (poutres, conduites...) dans le cas des Lits Mobiles Simulés. Cette représentation, quoique très simpliste, s'avère généralement suffisante tant que l’étalement des fronts de concentration est d'abord induit par les limitations au transfert externe, interne (macro/microporeux) et par la thermodynamique du système. Par contre, lorsque l’adsorbant employé présente d’excellentes performances de transfert, une approche aussi simple s'avère extrêmement risquée. En effet, les phénomènes dispersifs associés à l’adsorbant (transfert et thermodynamique) et à l’hydrodynamique ont des contributions de même ordre de grandeur sur la dispersion des fronts de concentration. Dans ce cas, une description plus réaliste de l'écoulement est requise afin de mieux appréhender son effet sur les performances de séparation.Dans ce contexte, l’objectif de ce projet de thèse est de mettre en place une méthodologie pour prendre en compte ces phénomènes hydrodynamiques lors de l’extrapolation d’un procédé de séparation par adsorption. Pour cela, nous proposons une étude du couplage entre les phénomènes hydrodynamiques et le phénomène d’adsorption. / Hydrodynamics inside industrial Simulated Moving Bed (SMB) adsorption columns can be complex due to the presence of internal distribution devices, free flow chambers and heterogeneous injections. These have to be taken into account in SMB numerical models to scale-up purposes. In the present thesis, a CFD approach is adopted as an intermediate step to develop a 1D model simple enough to be used for cyclic SMB simulations while being able to represent realistic hydrodynamics. This model results from the interpretation of the moments of the fluid age distribution, transported by CFD according to the method developed by Liu and Tilton (2010) that allows to estimate the degree of mixing (Liu, 2011) of the adsorption columns. The resulting 1D model consists in the two examples provided by Zwietering (1959) of a completely segregated system and a maximum mixedness system. This model is able to reproduce the residence time distribution of the CFD model of an adsorption column, while being representative of the internal flow patterns. This results in a good representation of the coupling of adsorption and hydrodynamics by the 1D model. When integrated in a SMB simulator and compared to the traditionally used dispersed plug flow model, the new 1D model demonstrates that for most of the adsorption column geometries considered a detailed hydrodynamic description is mandatory. Such detailed hydrodynamic description is even more important when employing adsorbents with better mass transfer performances than those currently used for the p-xylene purification, which is expected in the upcoming years.

Simulated Moving Bed (SMB) chromatography is a separation process where the components are separated due to their varying affinity towards the stationary phase. Over the past decade, many modifications have been proposed in SMB chromatography in order to effectively separate a binary mixture. However, the separation of multi-component mixtures using SMB is still one of the major challenges. Although many different strategies have been proposed, previous studies have rarely performed comprehensive investigations for finding the best ternary separation strategy from various possible alternatives. Furthermore, the concept of combining reaction with SMB has been proposed in the past for driving the equilibrium limited reactions to completion by separating the products from the reaction zone. However, the design of such systems is still challenging due to the complex dynamics of simultaneous reaction and adsorption. The first objective of the study is to find the best ternary separation strategy among various alternatives design of SMB. The performance of several ternary SMB operating schemes, that are proposed in the literature, are compared in terms of the optimal productivity obtained and the amount of solvent consumed. A multi- objective optimization problem is formulated which maximizes the SMB productivity and purity of intermediate eluting component at the same time. Furthermore, the concept of optimizing a superstructure formulation is proposed, where numerous SMB operating schemes can be incorporated into a single formulation. This superstructure approach has a potential to find more advantageous operating scheme compared to existing operating schemes in the literature. The second objective of the study is to demonstrate the Generalized Full Cycle (GFC) operation experimentally for the first time, and compare its performance to the JO process. A Semba OctaveTM chromatography system is used as an experimental SMB unit to implement the optimal operating schemes. In addition, a simultaneous optimization and model correction (SOMC) scheme is used to resolve the model mismatch in a systematic way. We also show a systematic comparison of both JO and GFC operations by presenting a Pareto plot of the productivity achieved against the desired purity of the intermediate eluting component experimentally. The third objective of the study is to develop an simulated moving bed reactor (SMBR) process for an industrial-scale application, and demonstrate the potential of the ModiCon operation for improving the performance of the SMBR compared to the conventional operating strategy. A novel industrial application involving the esterification of acetic acid and 1-methoxy-2-propanol is considered to produce propylene glycol methyl ether (PMA) as the product. A multi-objective optimization study is presented to find the best reactive separation strategy for the production of the PMA product. We also present a Pareto plot that compares the ModiCon operation, which allows periodical change of the feed composition and the conventional operating strategy for the optimal production rate of PMA that can be achieved against the desired conversion of acetic acid.

Orientador: Cesar Costapinto Santana / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-08T16:18:50Z (GMT). No. of bitstreams: 1 Dias_RaquelMacedo_M.pdf: 1158217 bytes, checksum: 17fc0268f6869b95e17b301e65d69e9c (MD5) Previous issue date: 2007 / Resumo: O mitotano (o,p?-diclorodifenildicloroetano) é um fármaco utilizado no tratamento de carcinoma adrenocortical. Ele é comercializado na forma racêmica, ou seja, na proporção 1:1 dos seus enantiômeros R e S. A influência da quiralidade da molécula sobre seu efeito farmacológico ainda não foi estudada. Portanto, a separação dos enantiômeros é importante para testes biológicos comparativos de efeitos colaterais. Este trabalho foi desenvolvido com o intuito de estudar a separação deste fármaco pela técnica de cromatografia líquida de alta eficiência utilizando coluna recheada com a fase estacionária quiral O,O?-bis[4-tercbutilbenzoil]-N,N?-dialil-L-tartardiamida. Diferentes combinações de fase móvel foram testadas e os melhores resultados foram obtidos com hexano/acetato de etila na proporção 95/5 (v/v). Experimentos de pulsos com soluções diluídas do traçador e dos enantiômeros do mitotano foram realizados variando a vazão de fase móvel e a temperatura do sistema. Foram determinados as porosidades do sistema, os parâmetros cromatográficos, os dados de equilíbrio, coeficientes de dispersão axial e parâmetros de transferência de massa. Os resultados mostraram separação satisfatória, com número de pratos superando 9000 e fatores de separação na ordem de 1,13. Os valores dos coeficientes de Henry foram maiores que a unidade para ambos os enantiômeros, sendo que o enantiômero mais retido R-(+)-mitotano, apresentou maior afinidade pela coluna quiral. Valores de km superiores a 300 min-1 revelaram baixo efeito dos fenômenos de transferência de massa e consequentemente predomínio dos efeitos termodinâmicos (energia entálpica superior -10 kJ/mol para os enantiômeros). Experimentos a altas concentrações foram realizados com a finalidade de se determinar às isotermas pelo método da análise frontal e também os cromatogramas sob estas condições. Para a concentração da mistura até 16 g/L as isotermas mostraram um bom ajuste ao modelo de Langmuir. A partir da separação em batelada determinaram-se as regiões de separação dos enantiômeros para um sistema cromatográfico contínuo do tipo leito móvel simulado para diferentes concentrações de alimentação da mistura racêmica. Avaliaram-se as variáveis desempenho (consumo de solvente e produtividade) no sistema contínuo e compararam-se com as obtidas em separações em batelada. Melhores resultados foram obtidos para um sistema contínuo do tipo leito móvel simulado / Abstract: Mitotane (o, p'-dichlorodiphenyldichloroethane) is a drug used in the treatment of adrenocortical carcinoma. It is marketed in the racemic form, proportion 1:1 of their R and S enantiomers. The influence of the molecule quirality on its pharmacology effect was not studied yet. For this reason, this separation is important for comparative biological tests of collateral effects. This work was developed with intention to study the separation of this drug via liquid chromatography using columns packed with the chiral stationary phase, O,O?-bis[4-terc-butylbenzoyl] - N, N' - diallyl-L-tartardiamide. Different combinations of mobile phase was tested and better results were achieved with hexane/ethyl acetate in ratio 95/5 (v/v). Pulses experiments with diluted solutions of the inert and the enantiomers were accomplished at different flow rates and temperature. The system porosities, chromatographic parameters, equilibrium constants, axial dispersion and mass transference parameters were obtained. The results showed satisfactory separation, with number of plates overcoming 9000 and separation factors in the order of 1,13. The values of Henry coefficients were greater than one for both enantiomers, the most retained was R (+) -mitotane, and it presented greater affinity for the chiral column. The overall mass transfer coefficient achieved values higher than 300 min-1, demonstrating low mass transfer effect rates and consequently a prevalence of the thermodynamic effects (enthalpy energy greater than -10 kJ/mol for the enantiomers). Experiments in overload conditions were realized in order to determining the isotherms using the method of the frontal analysis as well the chromatograms under these conditions. For the concentration of the mixture smaller than 16 g/L the isotherms showed a good adjusted to the Langmuir model. The separation regions for a chromatographic continuous system like simulated moving bed were determined with different feed concentrations. This permits the comparison of the performance parameters using the continuous system and batch ones / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestre em Engenharia Química

This dissertation describes the simulation and optimization of adsorptive and chromatographic separation processes. The first part focus on the simulation and comparison of operational modes in simulated moving bed (SMB) chromatography for separation and purification in bioprocesses. The second part includes the simulation of gas-phase adsorptive processes by pressure swing adsorption and temperature swing adsorption technologies. The applications of SMB chromatography are popular in separating and purifying enantiomers, petrochemicals, pharmaceuticals and biochemicals with higher yield and lower solvent consumption. We simulate and compare several operational modes of simulated moving bed (SMB) for a binary and a ternary bioprocess using Aspen Chromatography. These operational modes are able to improve the separation efficiency of the basic SMB process by our simulation and optimization. We compare their separation performances and identify heuristics that will guide the selection of operational modes across a variety of systems. Pressure swing adsorption (PSA) and temperature swing adsorption (TSA) are two of the main technologies for gas-phase adsorption separation processes. We simulate and demonstrate a PSA model for air separation system and a TSA model for CO2 capture system in Aspen Adsorption. We present their separation performance plots to provide the physical insights of these two systems. / Ph. D.

Adsorption separation processes are extremely important to the chemical industry, especially in the manufacturing of food, pharmaceutical, and fine chemical products. This work addresses three main topics: first, systematic decision-making between rival gas phase adsorption processes for the same separation problem; second, process development for liquid phase simulated moving bed chromatography (SMB); third, accelerated startup for SMB units. All of the work in this thesis uses model-based optimization to answer complicated questions about process selection, process development, and control of transient operation. It is shown in this thesis that there is a trade-off between productivity and product recovery in the gaseous separation of enantiomers using SMB and pressure swing adsorption (PSA). These processes are considered as rivals for the same separation problem and it is found that each process has a particular advantage that may be exploited depending on the production goals and economics. The processes are compared on a fair basis of equal capitol investment and the same multi-objective optimization problem is solved with equal constraints on the operating parameters. Secondly, this thesis demonstrates by experiment a systematic algorithm for SMB process development that utilizes dynamic optimization, transient experimental data, and parameter estimation to arrive at optimal operating conditions for a new separation problem in a matter of hours. Comparatively, the conventional process development for SMB relies on careful system characterization using single-column experiments, and manual tuning of operating parameters, that may take days and weeks. The optimal operating conditions that are found by this new method ensure both high purity constraints and optimal productivity are satisfied. The proposed algorithm proceeds until the SMB process is optimized without manual tuning. In some case studies, it is shown with both linear and nonlinear isotherm systems that the optimal performance can be reached in only two changes of operating conditions following the proposed algorithm. Finally, it is shown experimentally that the startup time for a real SMB unit is significantly reduced by solving model-based startup optimization problems using the SMB model developed from the proposed algorithm. The startup acceleration with purity constraints is shown to be successful at reducing the startup time by about 44%, and it is confirmed that the product purities are maintained during the operation. Significant cost savings in terms of decreased processing time and increased average product concentration can be attained using a relatively simple startup acceleration strategy.

Les procédés chromatographiques multicolonnes continus se sont imposés comme technique séparative dans l’industrie pharmaceutique en raison de leur productivité élevée et de leur développement rapide. De nos jours, la modélisation, le dimensionnement et l’optimisation des procédés LMS et Varicol sont considérés comme établis. Le fonctionnement automatique optimisé et robuste de ces procédés reste cependant un sujet de recherche. Le plus souvent, les paramètres opératoires sont choisis en deçà du réglage optimal afin d’inclure une marge de robustesse. Ils sont ajustés manuellement par un opérateur expérimenté pour maintenir les produits à leurs spécifications de pureté. Le nombre élevé de séparations chromatographiques rend crucial le développement d’une application d’un contrôle avancé de ces procédés. Récemment, plusieurs méthodes de contrôle des procédés LMS ont été proposées. Ce travail de thèse présente une nouvelle approche de contrôle avancé. Cette commande ajuste les paramètres opératoires d’une séparation grâce à deux types de mesure : une mesure en ligne et une mesure hors ligne. Une validation expérimentale du schéma de contrôle a été effectuée sur un procédé Varicol. Les résultats présentés démontrent que la commande permet d’amener la pureté des produits à leurs spécifications, d’optimiser les performances du procédé et de répondre aux perturbations, tout en sécurisant la pureté du produit cible / Multicolumn continuous chromatographic processes became a key separation technology in the areas of pharmaceutical industry thanks to high productivity and short process development times. Today, modeling, design, and optimization of SMB and Varicol, are well established. However a robust and optimized operation of processes is still an open issue. The common practice is to operate processes under suboptimal operating conditions in order to gain the necessary robustness. The operating parameters are tuned manually by experienced operators in order to maintain the product specifications. Therefore, as chromatographic applications spread, process control problem becomes increasingly important. Recently, several control methodologies of SMB process have been proposed. This thesis work introduces a new advanced control system approach. This system adjusts operating parameters thanks to two kinds of measurements : an in-line measurement and an at-line measurement. The performance of this control scheme is demonstrated through several experiments on Varicol. The reported results aim to demonstrate that the controller is able to deliver the products within the specifications, to optimize the process performance and to answer to disturbances while protecting the key product

Simulated moving bed chromatography process (SMBCP) is the technical realisation of a countercurrent adsorption process through the cyclic port switching. SMB technology reduces the cost of packing material with high loading capacity and provides high purity and high recovery in a very short time. Major commodity applications have been found in the petroleum, food, biotechnology, pharmaceutical and fine chemical industries. The industrial applications bring an emergent demand to improve the SMBCP operation for higher product quality, productivity, efficiency and robustness. However, for this particular process, we encounter several challenges. Firstly, the interplay of the effects of strong nonlinearities, competition of solutes, mass transfer resistance and fluid dynamic dispersion produces steep concentration fronts. Mathematical model accounted for this particular property constitutes a serious difficulty for the solution procedure. Secondly, a dynamic SMB model consists of a set of partial differential, ordinary differential and algebraic equations, which are highly coupled. The large size is a problem due to its intensive computation when on-line optimisation and real-time control are necessary. Thirdly, the SMB unit operation exhibits complex dynamics. Process metrics for design and operation can be determined only when a cyclic steady state is reached after a certain number of switching. Achieving this steady state by solving the PDE models cycle after cycle involves expensive calculation. Studies have been carried out to solve these problems through process analysis, investigation on spatial discretisation techniques, and development of an accelerated integration scheme. / Through a systematic study on the advances of SMB modelling, design and control, a set of functionally equivalent models for SMBCP are identified and summarized for their practical applications. The limitations of the existing modelling techniques in industrial applications are also identified. Furthermore, structural analysis of the existing models is conducted for a better understanding of the functionality and suitability of each model. Suggestions are given on how to choose an appropriate model with sufficient accuracy while keeping the computational demand reasonably low for real time control. / Effort is made on to the systematic investigation of different numerical methods for the solution of PDEs to circumvent the steep gradients encountered in chromatographic separation. Comprehensive studies are conducted on a single column chromatographic process represented by a transport-dispersive-equilibrium linear model. Numerical solutions from the upwind-1 finite difference, wavelet-collocation, and high resolution methods are evaluated by quantitative comparisons with the analytical solution for a range of Peclet numbers. It reveals that for a PDE system with a low Peclet number, all existing numerical methods work well, but the upwind finite difference method consumes the most time for the same degree of accuracy of the numerical solution. The high resolution method provides an accurate numerical solution for a PDE system with a medium Peclet number. The wavelet collocation method is capable of catching up steep changes in the solution, and thus can be used for solving PDE models with high singularity. / The advantages and disadvantages of the wavelet based approaches are further investigated through several case studies on real SMBCP system. A glucose-fructose separation process is firstly chosen with its relatively simple isotherm representations. Simulations are conducted using both wavelet collocation and upwind finite difference methods. For more complicated applications, an enantiomers separation process is selected. As the PDEs model exhibit a certain degree of singularity, wavelet collocation and high resolution methods are adopted for spatial discretisation. It is revealed that both the wavelet based approaches and high resolution methods are good candidates in terms of computation demand and prediction accuracy on the steep front. This is the first time that these two frontier numerical methods are used for such a complex SMB system models and our results are encouraging for the development of model-based online control scheme. / In developing a new scheme to rapidly obtain the solution at steady state for any arbitrary initial condition, the concept of Quasi-Envelope (QE) is adopted under the consideration that a SMBCP can be treated as a pseudo-oscillatory process because of a large number of continuous switching. The scheme allows larger steps to be taken to predict the slow change of starting state within each switching. Combined with previously developed wavelet-based technique, this method is successfully applied to the simulation of a SMB sugar separation process. Investigations are also carried out on the location of proper starting point for the algorithm and on the effect of changing stepsize to the convergence of iteration method. It is found that if the starting state of Quasi-Envelope is chosen to be the same as the original function, the multivalue algorithm would require similar computational effort to achieve the steady state prediction, regardless of the integration stepsize. If using constant stepsize, launching QE later is helpful when quasi-envelope displays steep change at the start-up period. A changing stepsize produces slow convergence compared to the constant stepsize strategy, thus increasing the work load where the stepsize change is occurring. Other iteration method is required to be imposed to achieve faster convergence right from the beginning. Potential applications can be seen for other chemical engineering processes with inherent cyclic behaviour.