Recovery of succinic acid in fermentation broth via reactive LL extraction: effect of chemical kinetics and solvent choice

In this paper, a study of kinetics effects on the reactive liquid-liquid extraction column is proposed. In a first part, design parameters of reactive liquid-liquid extraction column are derived from a method proposed by Mizzi (2016). In a second part, using a kinetic model, the performances of the column are studied with different configuration and design parameters. This study allows a comparison of the performances of the column in terms of conversion rate, recovery rate and purity. For the chosen examples, the kinetic limitation is very strong. So the unit operations of reactive liquid-liquid extraction with a high retention capacity will be privileged: a cascade of decanter mixers. In conclusion, this article shows that the choice of solvent and the parameters of the column as the solvent flowrate, the number of theoretical stage, liquid hold up or kinetics of the reaction have an important influence on the performances of the column and sometimes on the feasibility of the separation

General design methodology for reactive liquid–liquid extraction: application to dicarboxylic acid recovery in fermentation broth

A general design methodology for reactive liquid–liquid extraction is introduced in this paper. It is composed of three different steps: feasibility analysis, pre-design determination and simulation validation. This paper is focused on the first and the second step. This methodology leads to the design specifications of the units from the information concerning the physico-chemical behaviour of the studied system, exploiting the equilibrium and material balance equations. The results of this methodology are a good starting point for an optimization study or for an investment calculation process. This methodology has been applied to different case studies: two different strategies of extraction and several solvents to recover succinic acid in fermentation broth

Contribution à la modélisation dynamique simplifiée d'un procédé d'adsorption modulée en pression (P.S.A.)

One of the objectives of this study was to build a model able topredict the transient comportment and to quickly estimate thestate of the Pressure Swing Adsorption (P.S.A.) processes at thecyclic steady state. Computing time problems are still encounteredtoday, whereas a fast and reliable simulator is necessary for theprocess,optimal dimensioning and even for its control.Two approaches were so adopted. The first one consists inaccelerating the simulation of each step of the cycle bysimplifying the model of bidispersed pellet of adsorbent. Theapproach used to simplify the pellet model is close to the oneused to establish the traditional model of « Linear DrivingForce ». The influence on the model structure of the statevariables choice, as well as the influence of space distributionof resistances to the mass transfer in the pellet have beenstudied . The column global model based on this pellet model ledto simulations of breakthrough curves in good agreement with thosein the literature.The second approach is based on the approximation of the cyclicprocess by an equivalent continuous process. The simulatorobtained can estimate almost instantly the transient comportmentand the cyclic steady state of the system. For kineticseparations, simulations using this model are in good agreementwith those obtained using a traditional cyclic model.The other objective of this work was to design a P.S.A. pilot,entirely controlled by computer, which allows to follow the outletcompositions, as well as temperature profiles in each column. Anexperimental study has been done on this pilot. It relates to theseparation of methane and carbon dioxide mixtures on a zeolite 5A.This study, associated with the experimental results in theliterature, validates our first model.L'un des objectifs de cette étude était de proposer un modèlecapable de prédire le régime transitoire et d'estimer rapidementl'état des procédés cycliques de séparation de gaz par adsorptionmodulée en pression (P.S.A.) en régime établi. En effet, desproblèmes de temps de calcul se posent encore de nos jours, alorsqu'un simulateur rapide et fiable est nécessaire audimensionnement optimal du procédé, voire son contrôle.Dans ce but, deux approches ont été adoptées. La première consisteà accélérer la simulation de chacune des étapes du cycle ensimplifiant le modèle de grains d'adsorbant bidisperses. Ladémarche suivie pour simplifier le modèle intra-granulaire estproche de celle employée pour établir le modèle classique de« Linear Driving Force ». Une étude a été menée concernant lechoix des variables d'état et la répartition spatiale desrésistances au transfert de matière dans le grain. Ces deuxparamètres ont en effet tous deux une influence sur la structuredu modèle. Le modèle global de colonne basé sur ce modèleintra-granulaire conduit à des simulations de courbes de perçageen bon accord avec celles de la littérature.La seconde approche repose sur l'approximation du procédé cycliquepar un procédé continu équivalent. Le simulateur basé sur cemodèle permet d'estimer à la fois la mise en régime et l'état dusystème en régime établi de façon quasi-instantanée. Pour desséparations de type cinétique, les simulations obtenues avec cemodèle sont en bon accord avec celles obtenues avec un modèlecyclique classique.L'autre objectif de ce travail était de concevoir un pilote deprocédé P.S.A. intégralement contrôlé par informatique, permettantde suivre les compositions de sortie, ainsi que les profils detempérature dans chaque colonne. Une étude expérimentale a étémenée sur ce pilote. Elle porte sur la séparation de mélanges deméthane et de dioxyde de carbone sur une zéolithe 5A. Cette étude,associée aux résultats expérimentaux de la littérature, permet devalider notre premier modèle

Contribution à la modélisation dynamique simplifiée d'un procédé d'adsorption modulée en pression (PSA)

One of the objectives of this study was to build a model able to predict the transient comportment and to quickly estimate the state of the Pressure Swing Adsorption (P.S.A.) processes at the cyclic steady state. Computing time problems are still encountered today, whereas a fast and reliable simulator is necessary for the process,optimal dimensioning and even for its control. Two approaches were so adopted. The first one consists in accelerating the simulation of each step of the cycle by simplifying the model of bidispersed pellet of adsorbent. The approach used to simplify the pellet model is close to the one used to establish the traditional model of Linear Driving Force . The influence on the model structure of the state variables choice, as well as the influence of space distribution of resistances to the mass transfer in the pellet have been studied . The column global model based on this pellet model led to simulations of breakthrough curves in good agreement with those in the literature. The second approach is based on the approximation of the cyclic process by an equivalent continuous process. The simulator obtained can estimate almost instantly the transient comportment and the cyclic steady state of the system. For kinetic separations, simulations using this model are in good agreement with those obtained using a traditional cyclic model. The other objective of this work was to design a P.S.A. pilot, entirely controlled by computer, which allows to follow the outlet compositions, as well as temperature profiles in each column. An experimental study has been done on this pilot. It relates to the separation of methane and carbon dioxide mixtures on a zeolite 5A. This study, associated with the experimental results in the literature, validates our first modelL'un des objectifs de cette étude était de concevoir des modèles de procédé d'adsorption modulée en pression. Pour cela, nous avons développé deux modèles. Le premier modèle s'appuie sur une simplification du modèle de transfert intra-particulaire dans des adsorbants bidisperses. La seconde approche repose sur l'approximation du procédé cyclique par un système continu équivalent. L'autre objectif de ce travail était de concevoir un pilote de procédé d'adsorption modulée en pression, intégralement contrôlé par informatique. Une étude expérimentale a été menée sur ce pilote. Elle porte sur la séparation de mélanges de méthane et de dioxyde de carbone sur une zéolithe 5A. Cette thèse a été financée par le Ministère de la Recherche. Elle a aussi bénéficié de l'aide financière du projet européen GeoPleX (EU-IST-2001-34166), et a fait l'objet de plusieurs conventions de collaboration avec l'Institut Français du PétroleLYON1-BU.Sciences (692662101) / SudocSudocFranceF

Design of a Pressure Swing Adsorption Process for Postcombustion CO₂ Capture

The adsorption processes for postcombustion CO₂ capture are usually based on a temperature or vacuum swing (TSA or VSA). In the present contribution an alternative concept is presented, which is based on the regeneration of the solid sorbent (an immobilized amine) by a purge gas, low pressure vapor, under almost isothermal conditions. Because of the close to isothermal operation, the process consumes significantly less thermal and mechanical energy than conventional TSA and VSA processes, respectively. We present a rough design of such an isothermal concentration swing process based on a simplified, analytical model of a 2-step PSA (pressure swing adsorption) process. The analytical model allows a definition of the range of operating conditions that lead to the best compromise between energy consumption and productivity (size and number of the adsorbers). Moreover, it is possible to define the equilibrium and mass transfer properties of the ideal solid sorbent. The feasibility of the concentration swing process was finally validated by numerical simulations of a full PSA cycle under adiabatic conditions

A double linear driving force approximation for non-isothermal mass transfer modeling through bi-disperse adsorbents

International audienceThe aim of this paper is to derive a double LDF non-isothermal model to describe mass transfer through a fixed bed of bi-disperse adsorbent pellets. Firstly, we perform an analysis concerning the different way the composition within the pellets can be described and the consequence on the model structure and compactness. Secondly, we present a bed model including a simplified intra-particle model that is based on a double LDF approximation. This bi-disperse pellet model reduces the number of variables and parameters that are needed. This simplified model is used to simulate breakthroughs of a methane/carbon dioxide mixture over a 5 A zeolite and of a 2,2-dimethylbutane/2-methylpentane mixture over a silicalite molecular sieve. It is also compared with a more detailed model based on Stefan–Maxwell theory that we have previously developed

Random porous network generation and 1D mass transfer simulation for gamma-alumina supports

International audienceA two or three-dimensional pore network is randomly generated by a Monte Carlo approach to represent γ-alumina supports. The network porous structure is obtained by the random interconnection of cylindrical pores. The proposed model allows to correctly represent the catalyst support pore size distribution, the porosity and internal surface area. Transient mass transfer is simulated in 1D within each pore of the network and tortuosity factors are estimated as a function of porosity. Confrontation of the predicted diffusion properties with both theoretical and experimental values from fixed-bed tracer experiments showed that the network structure agrees with theoretical tortuosity-porosity relations. However, real alumina supports exhibit higher tortuosities, which are probably due to the presence of two levels of porosities

Hydrodynamic modelling of complex fixed bed geometries in simulated moving bed adsorption processes

International audienceHydrodynamics inside industrial Simulated Moving Bed (SMB) adsorption columns can be complex due to the presence of internal distribution devices. They have to be taken into account in SMB numerical models to scale-up processes. In the present work, CFD is used 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. First, a mock-up representative of an industrial SMB is used to perform Residence Time Distribution (RTD) experiments and to provide validation data. Experiments are well predicted by a CFD model including porous media and turbulent zones, allowing to consider CFD simulations as references to fit simpler models. The moments of internal age distribution are characterized following the calculation method developed by Liu and Tilton (2010), which allows to estimate the degree of mixing (Liu, 2012) inside adsorption beds. A major result is that RTD and degree of mixing inside adsorption beds are well described by a 1D multi-exit model, unlike classical dispersed plug flow models (Ruthven, 1989) that were generally used to simulate SMB processes. Additionally, a numerical method was developed which is able to reproduce the RTD with steady state simulations

Procédé d’estérification d’un diol mettant en œuvre une distillation réactive

L'invention concerne un procédé de conversion alimenté par une charge diol comprenant au moins 90% poids de diol et une charge acide carboxylique comprenant au moins 80% poids d'acide carboxylique, ledit procédé comprenant au moins : - une étape d'estérification, alimentée par au moins ladite charge diol et au moins ladite charge acide carboxylique, les débits d'alimentation étant ajustés de telle sorte que le ratio molaire acide carboxylique/diol en entrée de ladite étape d'estérification est compris entre 2 et 6, ladite étape d'estérification comprenant au moins une colonne de distillation réactive opérée à une température comprise entre 40 et 280°C, à une pression comprise entre 0,01 et 0,5 MPa, avec un taux de reflux molaire compris entre 0,5 et 10 et un taux de rebouillage molaire compris entre 0,5 et 10, constituée d'une zone mixte de réaction/séparation située entre deux zones de séparation, chacune desdites zones de séparation ayant une efficacité d'au moins deux étages théoriques, ladite zone mixte comprenant un catalyseur hétérogène acide, ladite étape d'estérification produisant au moins un distillat comprenant de l'eau et un résidu diester de diol ; - une étape d'élimination de l'eau alimentée par ledit distillat comprenant de l'eau et produisant au moins un effluent eau

Modelling of a Simulated Moving Bed in case of non-ideal hydrodynamics

International audienceThe one-dimensional hydrodynamic model proposed by Gomes et al. (2015) is coupled with adsorption and validated by comparing the concentration profiles of this one-dimensional model with those given by the CFD model of one adsorption column including obstacles as distribution network and beams. This one-dimensional model is capable of predicting the CFD results for different mass transfer rates, while the traditional dispersed plug flow (DPF) model is accurate for slow mass transfer rates only. The model proposed by Gomes et al. (2015) is capable of reproducing the adsorber Residence Time Distribution (RTD) while dissociating the selective zones from the non-selective ones. It is based on the CFD techniques developed by Liu and Tilton (2010) and Liu (2012) that transport the moments of the fluid age distribution and consequently calculate the degree of mixing (Danckwerts, 1958 and Zwietering, 1959). Then, this new model is integrated in a cyclic solver in order to perform Simulated Moving Bed (SMB) studies. The new model provides a detailed hydrodynamic description, which appears to be mandatory especially when mass transfer exchanges are fast, without undergoing the prohibitive simulation times of CFD models