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International audience; On industrial sites, the promotion of best practices to enable an efficient utilization of energy has emerged as one of the major point of focus. Among the different approaches existing to improve industrial processes, the exergy analysis, although limited to the academic world, has been shown to be a powerful tool for improving energy efficiency of thermal and chemical systems. The purpose of this paper is then to present the use of the ProSimPlus® modelling and simulation environment as an exergy analysis computer-aided tool. Expressions implemented in the simulator for computing exergies in its various forms are presented. The adopted approach for calculating exergy efficiency in a systematic way is also exposed; it combines the fuel-product concepts to the transit exergy concept. ProsimPlus® exergy module's capabilities are illustrated through the example of an ammonia production plant.

Reverse electrodialysis (SGP-RE or RED) represents a viable technology for the conversion of the salinity gradient power into electric power. A comprehensive model is proposed for the RED process using sea or brackish water and concentrated brine as feed solutions. The goals were (i) reliably describing the physical phenomena involved in the process and (ii) providing information for optimal equipment design. For such purposes, the model has been developed at two different scales of description: a lower scale for the repeating unit of the system (cell pair), and a higher scale for the entire equipment (stack). The model was implemented in a process simulator, validated against original experimental information and then used to investigate the influence of the main operating factors and on power output. Feed solutions of different salinities were also tested. A good matching was found between predictions and experiments for a wide range of inlet concentrations, flow rates and feed temperatures. Optimal feed conditions, for the adopted system geometry and membranes, have been found employing brackish water (0.08–0.1 M NaCl) as dilute and brine (4.5–5 M NaCl) as concentrate to generate the highest power density at 40 °C temperature. The model can be used to explore the full potential of the RED technology, especially for any investigation regarding the future scale-up of the process.

In recent years, thanks to the development of ion exchange membranes (IEMs) manufacturing industry, Electrodialysis (ED) is spreading as a viable alternative to the more common membrane desalination processes. Therefore, many research efforts have been recently devoted to studying this process both via experimental and modelling activities. In the present work a novel mathematical model for ED was developed using a multi-scale approach. This method allows to build a hierarchical simulation tool that is able to gauge the impact of all the phenomena involved in the process. The lower-hierarchy model describes the behaviour of the elementary unit of an ED stack, namely cell pair. This model is based on differential mass balance equations and accounts for transport phenomena including salt migration and diffusion as well as water osmosis and electro-osmosis. In addition, Kirchhoff’s law together with the Nernst’s law for the non-Ohmic voltage drop was used to determine the electrical behaviour of the equivalent circuit. Interestingly, the model makes also use of CFD correlations from a lower scale as input data in order to predict the effect of concentration polarization. In the higher-hierarchy model the whole stack was described, allowing the simulation of multiple cell-pairs together with the end electrode compartments. Again, CFD correlations were used to include the contribution of pumping loss in the overall energy consumption. The model was implemented in PSE gPROMS Modelbuilder. Several simulations were carried out by changing flow arrangement (co-current, counter-current and cross-flow), operating conditions and stack features. Results showed that the model is able to reliably predict the effect of these variables on the performance of the ED unit investigated. In particular, the model was found capable of estimating the distribution of current density/voltage and concentration along the channels. In addition, stack resistance, overall and specific energy requirements were computed. Collected findings suggest that the model proposed might be a powerful tool to improve and optimise ED process.

In this study, we introduced a novel and generalized calculation method to reproduce the deposition profiles in various types of chemical vapor deposition reactors. Robust and accurate calculations along with reduced computing cost were achieved by this method. Both boundary value problems and initial value problems for estimating the mass balance equations of the deposition species by iterations of numerical integrations were changed into problems of finding the linear combinations consisting of a few “basis functions,” which are inherent in the reactors and deposition species. The coefficients of the linear combinations were optimized using genetic algorithms. We could demonstrate the validity of the proposed method using various examples of the reaction mechanisms and conditions.

Determination of process structure of thermal utilization of mineral mat?ters from waste streams, is a multi-variant problem. These processes are energy-intensive and it is very important to determine the process structures for realization of the required processes in the starting phases of process development. The structure of the process system, beside the system equilibrium, depends on vector parameters of the feed stream. In this work a newly developed methodology for determination of process variants of thermal utilization of mineral salts from a hypothetical three-component AX-BX-H2O system is presented. The methodology is created on starting synthesis problem for which a set of types of process units for realization process and type of desired crystal product is determined. The methodology includes process decomposition in two subsystems: concentration (saturation) subsystem and crystallization subsystem. Concentration of feed stream is realized in isothermal conditions of water evaporation and crystallization process using various techniques: isothermal water evaporation, cooling of solution in vacuum and cooling of solution through contact surface. Determination of physical feasible processes is performed by simulation of the process superstructure in which each particular process structure is a special case of the created process superstructure. Realization of mentioned activity is provided by creating algorithms and programming software (process simulator) in which the equation system of the superstructure mathematical model is solved for various variants of set of specified variables. The created methodology and possibilities of the created process simulator are presented in the illustrative case study of waste stream utilization of the NaCl-KCl-H2O system. In addition to this, for conditions of total heat integration of subsystems is demonstrated that a small change of salt concentration of feed stream can require transfer non-cyclic in cyclic process structure.

The Reverse Electrodialysis (RED) process has been widely accepted as a viable and promising technology to produce electric energy from salinity difference (salinity gradient power - e.g. using river water/seawater, or seawater and concentrated brines). Recent R&D efforts demonstrated how an appropriate design of the RED unit and a suitable selection of process conditions may crucially enhance the process performance. With this regard, a process simulator was developed and validated with experimental data collected on a lab-scale unit, providing a new modelling tool for process optimisation. In this work, performed within the REAPower project (www.reapower.eu), a process simulator previously proposed by the same authors has been modified in order to predict the behaviour of a cross-flow RED unit. The model was then adopted to investigate the influence of the most important variables (i.e. solution properties and stack geometry) on the overall process performance. In particular, the use of different concentrations and flow rates for the feed streams have been considered, as well as different aspect ratios in asymmetric stacks. Moreover, the influence of the scaling-up a RED unit was investigated, starting from a 22x22 cm2 100 cell pairs lab-stack, and simulating the performance of larger stacks up to a 44x88 cm2 500 cell pairs unit. Finally, different scenarios are proposed for a prototype-scale RED plant, providing useful indications for the technology scale-up towards 1 kW of power production, relevant to the installation of a real prototype plant in Trapani (Italy) being the final objective of the R&D activities of the REAPower project.

Reverse Electrodialysis (SGP-RE or RED) process has been widely accepted as a viable and promising technology to produce electric energy from salinity difference (i.e salinity gradient power - e.g. using river water/seawater, or seawater and concentrated brines). Recent R&D efforts demonstrated how an appropriate design of the SGP-RE unit and a suitable selection of process conditions may crucially enhance the process performance. With this regard, a process simulator was developed and validated with experimental data collected on a lab-scale unit, providing a new modelling tool for process optimisation. In this work, performed within the REAPower project (www.reapower.eu), the process simulator previously proposed by the authors has been adopted for a wide sensitivity analysis of the SGP-RE process. The aim of this analysis is to investigate the influence of the most relevant variables (i.e. solution properties, stack geometry) on the overall process performance. In particular, the use of different salt concentration for feed streams, as well as flow rates and membrane sizes have been taken into account as optimisation variables. Different stack sizes were investigated, starting from a 10x10 cm2 lab-stack, up to a 44x100 cm2 large prototype unit. Finally, different scenarios are proposed for a prototype-scale plant, providing useful indications for the technology scale-up towards 1 kW of power production. These model predictions will be eventually used to address the economic feasibility of the SGP-RE technology for large scale applications.

Because of public health problems, the food industry must lower sodium content in all food products, therefore in cured meat products. During the dry-cured ham elaboration process, decreasing salt content may induce microbial safety problems and texture defects due to an excessive proteolysis that could affect later the industrial stage of slicing. On account of that, this work of thesis aims at (1) studying the relationship between proteolysis, structure and texture during the various stages of dry-cured ham manufacture, and (2) building a “numerical ham” model to predict spatially the time course of water and salt content, and thus water activity (a w ), and to couple these variations with proteolysis. This work combines experimental studies and numerical modelling and simulation. Firstly, a new and powerful technique for quantifying proteolysis that uses “Fluorescamine” was developed and validated on pork meat samples and samples extracted from industrial dry-cured hams; a new proteolysis index (PI) was defined. Based on an experimental design, the time course of proteolysis was quantified in laboratory-salted and dried pork meat samples prepared from five different types of pork muscle. Applying multiple linear regression enabled us to build phenomenological models relating, for each pork muscle, PI velocity to temperature, and to water and salt content. Using Comsol ® Multiphysics software, these phenomenological models were then combined with heat and mass transfer models and associated with calculation of a w , thus constituting the “numerical ham” model. In addition, the time course of PI, five textural parameters (hardness, fragility, cohesiveness, springiness and adhesiveness), and four structural parameters (fiber number, extracellular spaces, cross section area, and connective tissue area) was quantified on samples extracted from two different muscles of industrial dry-cured hams removed from the process at five different processing times. Multiple polynomial regression was applied to build phenomenological models relating PI, salt and water content to some textural and structural parameters investigated. These last models could be rapidly incorporated in the “numerical ham” model to constitute a real process simulator. In the future, the “numerical ham” model should be improved in order to take into account (1) the strong decrease in ham volume due to drying and also (2) the decrease in proteolysis velocity with time as a result of the reduction in the amount of protein that can be hydrolysed in the ham. Once completed and improved, the process simulator will be available to professionals to test scenarios allowing sodium content to be reduced in dry-cured hams without altering their final quality.; Du fait de problèmes de santé publique, l’industrie agroalimentaire doit réduire la quantité de sel (chlorure de sodium) dans les aliments, et donc dans les charcuteries. Lors de la fabrication des jambons secs, une diminution du taux de sel pourrait se traduire par des problèmes de texture dus à une protéolyse excessive pouvant nuire à l’étape de tranchage industriel, et aussi par des problèmes de stabilité microbiologique. Dans ce contexte, les objectifs de cette thèse sont : (1) d’étudier le lien entre l’évolution de la protéolyse, de la texture et de la structure, tout au long des différentes étapes de fabrication de jambons secs et (2) de développer un modèle de « jambon numérique » afin de prédire spatialement les dynamiques d’évolution des teneurs en eau, en sel et celle de l’activité de l’eau (a w ), et de coupler ces évolutions à celle de la protéolyse. Ce travail combine études expérimentales et modélisation/simulation numérique. Tout d’abord, une méthode de quantification de la protéolyse utilisant la « Fluorescamine » a été développée et validée sur des échantillons de viande de porc et des échantillons extraits de jambons industriels ; un nouvel indice de protéolyse (IP) a été défini. Sur la base d’un plan d’expériences, l’évolution de la protéolyse au sein d’échantillons différemment salés et séchés et préparés à partir de 5 muscles différents d’un jambon de porc, a été quantifiée. Suite à l’application d’une régression linéaire multiple, des lois phénoménologiques ont été construites permettant de calculer la vitesse de protéolyse, pour un muscle donné, en fonction de la température et des teneurs en eau et en sel. Ensuite, au moyen du logiciel Comsol ® Multiphysics, ces lois ont été combinées avec des modèles de transferts de matière (eau, sel), de chaleur (température), et de calcul de l’a w , constituant ainsi un modèle de « jambon numérique ». Enfin, la dynamique d’évolution de l’IP, de 5 paramètres texturaux (dureté, fragilité, cohésion, élasticité et adhésion) et de 4 paramètres structuraux (nombre des fibres, espaces extracellulaires, taille des fibres et surface de tissu conjonctif) a été mesurée sur des échantillons prélevés dans deux muscles extraits de jambons industriels pris à cinq stades de fabrication différents. L’application d’une régression polynômiale multiple à ces données expérimentales a conduit à l’établissement de corrélations permettent de calculer certains paramètres texturaux et structuraux à partir de l’IP et des teneurs en eau et en sel. A court terme, ces lois seront incorporées dans le modèle numérique afin de constituer un vrai simulateur de procédé. A moyen terme, le modèle de « jambon numérique » devra être amélioré afin de tenir compte (1) de la diminution du volume du jambon, du fait du séchage et (2) de la diminution de la vitesse de protéolyse en fonction du temps, du fait de la réduction de la quantité de protéines hydrolysables dans le jambon. Une fois complété et amélioré, le simulateur de procédé pourra aider les professionnels à tester des scénarios visant à réduire la quantité de sodium dans les jambons secs, sans altérer leur qualité finale.

Energy issue is becoming increasingly crucial for industrial sector that consumes large quantities of utilities. Although the scientific world should continue to look for alternate sources of energy, a short-term solution would rather rely on a more rational use of energy. To face this challenge, exergy analysis appears a very efficient tool as it would enable to increase efficiency and reduce environmental impact of industrial processes. Unfortunately, contrary to enthalpy, this concept is rather difficult to handle and exergy analysis is rarely implemented in process simulators. In this context, the major objective of the study presented in this dissertation is to make exergy analysis more understandable by coupling it with the use of a process simulator and also to demonstrate the value of this approach for analysis of energy efficiency of processes and utilities. This dissertation presents a generic formulation for exergy of material streams that does not depend on the thermodynamic model, so that it could be easily implemented in a process simulator. The different contributions of exergy (thermal, mechanical and chemical) have been developed and new concept such as the maximal thermal and mechanical recovery potential has been introduced in order to pave the way for exergy analysis. The formulations of exergy balances on a real process are presented. For that purpose, the formulation of exergy for heat and work flux is developed. The formulation of exergy balances has been introduced for both design and retrofit situations and then a set of hints for the interpretation of this exergy balance has been given. Synthetic tables providing solutions to reduce irreversibilities and external losses have been introduced. Moreover, different kinds of exergy efficiency have been defined to provide a new criterion for the optimization of the process. A new structured methodology for exergy analysis is developed to overcome the limitations of existing methodologies. To make exergy analysis easier for any engineer, a first prototype has been developed to implement the calculation of exergy for the material streams in a process flowsheet modeled in ProSimPlus. Thanks to this prototype, exergy of each material stream appears in a synthesis table next to the traditional thermodynamic values such as the enthalpy. Finally, a case study on Natural Gas Liquids recovery process is presented to demonstrate the benefit of the exergy analysis for the improvement of existing processes. First, the exergy analysis permits to make an energy diagnosis of the process: it pinpoints the inefficiencies of the process which relies not only on irreversibilities but also on external exergy losses. Then, based upon respective values of internal and external losses and also thanks to the breaking down of exergy into it thermal, mechanical and chemical contributions, some technological solutions are suggested to propose a retrofit process. Finally, the exergy efficiency criteria enable to optimize the operating parameters of the process in order to improve its energy efficiency.

This paper presents a general methodology for exergy balance in chemical and thermal processes integrated in ProSimPlus (R) as a well-adapted process simulator for energy efficiency analysis. In this work, as well as using the general expressions for heat and work streams, the whole exergy balance is presented within only one software in order to fully automate exergy analysis. In addition, after exergy balance, the essential elements such as source of irreversibility for exergy analysis are presented to help the user for modifications on either process or utility system. The applicability of the proposed methodology in ProSimPlus (R) is shown through a simple scheme of Natural Gas Liquids (NGL) recovery process and its steam utility system. The methodology does not only provide the user with necessary exergetic criteria to pinpoint the source of exergy losses, it also helps the user to find the way to reduce the exergy losses. These features of the proposed exergy calculator make it preferable for its implementation in ProSimPlus (R) to define the most realistic and profitable retrofit projects on the existing chemical and thermal plants. (C) 2012 Elsevier Ltd. All rights reserved.

International audience; The aim of this study was to describe a thermal aggregation process at laboratory scale by using an experimental process simulator. This device is able to impose fast variations of temperature and shear in the same range as in industrial equipments. Thermally-induced aggregation was studied on β-lactoglobulin (β-lg) solutions. We observed the influence of two parameters, protein concentration and treatment duration, on the final product characteristics: aggregate size and concentration and viscosity changes. By using both rheological characterization and size analysis by Focus Beam Reflectance Method (FBRM), it is possible to describe precisely the modification occurring during thermal treatment and to easily explore the influence of the different process parameters. As expected, aggregation depends strongly on the initial protein concentration. For a same thermo-mechanical treatment, more aggregates above 1μm are formed in the 6% protein solution compare to the 2% solution. For a heat treatment at 85 °C and 100 s-1 of a 6% β-lg solution with 6.6 mM of CaCl2 the viscosity of the solution significantly increase, mostly in the first 150 seconds of the treatment. By post cooling FBRM characterization, it has been shown that the formation of large particles (20-1000 μm) also occurs at the beginning. Increasing holding time would increase the concentration of small particles but not the viscosity and the concentration of large particles.

Using depth sensor cameras such as the Kinect and highly customizable software development frameworks in conjunction with artificial intelligence methodologies offer significant opportunities in a variety of applications, such as undergraduate science, technology, engineering, and math (STEM) education, professional or military training simulation, and individually-tailored cultural and media arts immersion. Designing a participatory educational experience where users are able to actively interface and experience given subject matter in a practical experiential manner can enhance the user's ability to learn and retain presented information. Such natural gesture user interfaces have potential for broad application in disciplines ranging from systems engineering education to process simulation. This paper will discuss progress on the development of testing environments for interactive educational methods in conjunction with artificial intelligent systems that have the ability to adjust the educational user experience based on individual user identification. This will be achieved through depth sensor skeletal tracking, allowing experience adaptation based on the nature and effectiveness of the interactive educational experience.

In the field of non-energy use of fossil fuels, energy and material flows are very complex. We developed a process chain model to understand the interlinkages and the resulting CO 2 emissions of such a system. This work aims to assess the implications of structural changes in production processes together with recycling strategies and production rates. The model is based on data for West Germany in 1989. Starting from an Excel spreadsheet model for mass flows we began to transfer our model to a conventional process simulator in order to test the optimizing capabilities and the balance options for material and energy flows. Due to the complexity of the task, we tested the usefulness of the simulator for the envisioned purposes using a small example for the production of PVC. The first results of a sensitivity study and an optimization run for recycling strategies are presented. Finally, the advantages and disadvantages of using a process simulator for the modelling of process chains is discussed.