De nos jours, de nouvelles technologies sont développées pour produire efficacement des produits dérivés de matières premières autresque le pétrole, comme par exemple la biomasse. En effet, la biomasse et plus spécifiquement la biomasse non alimentaire possède un fort potentielcomme substitut aux ressources fossiles pour des raisons environnementales, économiques et politiques. Dans ce contexte, l’étude des bioraffineries offre de nouvelles opportunités pour le Process System Engineering et plus particulièrement pour des activités de recherche quivisent la conception de systèmes constitués d’entités interconnectés. En effet, le verrou principal se concentre sur la modélisation et l’optimisation multi-échelle de la bioraffinerie qui permet l’intégration de plusieurs échelles spatiales allant de l’échelle moléculaire à celle de l’unité de production. Ces différentes échelles sont essentielles pour décrire correctement le système puisqu’elles interagissent en permanence. La forte dilution des courants est le meilleur exemple pour illustrer ces interactions. En effet, la présence d’eau induit de nombreux problèmes thermodynamiques (azéotropes, etc.) à l’échelle moléculaire, ce qui impacte fortement la topologie du procédé notamment sur les étapes de séparation, de purification et detraitement des purges (pour limiter les pertes en produits). Ainsi, la performance de la séquence d’opérations unitaires de l’étape de purification dépend entièrement de la concentration en eau. De plus dans la conception de bioraffinerie, il est fréquent de coupler fermentation et séparation afin d’améliorer les performances de la fermentation et de limiter la présence d’eau dans l’étapede purification. Par ailleurs, la grande quantité d’eau à chauffer ou refroidir entraine la nécessité de réaliser l’intégration énergétique du réseaud’échangeurs du procédé afin de minimiser le coût les dépenses énergétiques. L’objectif de ce travail est alors de proposer une méthodologie générique et les outils associés afin de lever certains verrous de la modélisation et l’optimisation multi-échelle de la bioraffinerie. Basée sur une approche par superstructure, la finalité de la méthodologie est d’évaluer les performances des alternatives étudiées en termes technico-économiques, environnementaux et d’efficacité énergétique en vue de son optimisation multi-objectifs pour trouver la voie de traitement optimale pour le(s) bioproduit(s) d’intérêt. Le cas d’application retenu se focalise sur la production de biobutanol à partir du système Acétone-Butanol-Ethanolet d’une biomasse d’origine forestière. La première étape de la méthodologie proposée concerne la création de la superstructure de la bioraffineriebasée sur une décomposition de cette dernière en 5 étapes principales : le prétraitement, la fermentation, la séparation, la purification et letraitement des purges. Ensuite, la seconde étape consiste à modéliser chaque alternative de procédé. Cette modélisation utilise un modèlethermodynamique à coefficients d’activité afin de décrire le comportement fortement non-idéal des molécules du milieu. De plus, l’intégration du traitement des purges et de l’intégration énergétique durant cette étape permet d’améliorer le procédé. Enfin, la dernière étape s’intéresse à l’optimisation multiobjectif qui se focalise sur différents aspects : maximisation de la production, minimisation des coûts, du prix minimal de vente des bioproduits, des pertes en produits et de l’impact environnemental. Cette dernière étape inclut également des études de sensibilité sur les différents paramètres de la méthodologie : opératoires, économiques, environnementaux... A l’issu de l’optimisation, un compromis seratrouvé afin d’obtenir une bioraffinerie durable. / Nowadays, to replace chemical products derived from petrol, new technologies are developed to produce products derived from others feedstock than crude oil like biomass. Indeed, biomass and especially nonfood biomass has a high potential as substitute due to its environmental, economic and political interests. Inthis context, the study of biorefineries offers new opportunities in the Process System Engineering and especially in research activities which aim to design systems with interlinked compounds. Indeed, the main hurdle focuses on the modeling and the multiscale optimization of thebiorefinery that allows integratingseveral spatial scales from the molecular scale to the plant scale. These scales are essential to describe accurately the system because they interact. The large dilution of flows is the best example to show these interactions. Indeed, water induces many thermodynamic problems (azeotropes, etc.) at the moleculescale, that impact on the process design and mainly on the separation, the purification and the treatment of purges (to limit losses of products). In consequence, the sequence of unit operations of the purification step depends of the water concentration. Furthermore, in the design of the biorefinery, the fermentation and theseparation are usually combined in order to improve performances of the fermentation and limit the water concentration in the purification step. Moreover, the large amount of water that needs to be heated or cooled induces the need of the energy integration of the heat exchangers network to minimize energy consumption. The aim of this work is to propose a generic methodology with connected tools in order to overcome some hurdles caused by the modeling and the multiscaleoptimization of the biorefinery. Based on the superstructure approach, the purpose of the methodology is to estimate performances of considered alternatives in the technical, economic, environmental and energy efficient aspects in preparation for the multiobjective optimization which finds the optimal process for the productionof the interesting bioproduct. This work focuses especially on the production of biobutanol through the Acetone-Butanol-Ethanol system from forest biomass. The methodology begins with the creation of the superstructure of the biorefinery composed by 5 major steps: the pretreatment, the fermentation, the separation, the purification and the treatment of purges. Next, the methodology consists in modeling each alternative of process. It integrates a thermodynamic model with activity coefficients in order to describe accurately the greatly nonideal behavior of molecules. Moreover, the treatment of purges and the energy integration are integratedat this step in order to improve the process. Finally, the last step interests to the multiobjective optimization which focuses on different aspects: the maximization of production and the minimization of the costs, the minimal selling price of bioproducts, the losses of bioproducts and the environmental impact. This step includes also sensitivity analysis on different parameters of the methodology: operating, economic, environmental… After the optimization, a compromise is made in order to obtain sustainable biorefinery.

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A demethaniser process is characterised by interactions between the complex distillation column and other flowsheet units, including the turbo-expander, flash units, multistream exchangers and refrigeration system. When a design problem dealing with demethaniser flowsheets is approached in a systematic way, the number of alternatives to be studied is generally very large. The assessment of all possible flowsheets with numerous options is a time consuming task with many simulations required to select the most economic option. This research presents a systematic approach for demethaniser flowsheet synthesis to generate cost-effective designs with minimal time and effort. A demethaniser column has many degrees of freedom, including the operating pressure, multiple feeds, the number and duty of side reboilers and the flow rate of the external reflux stream. The additional feed and side reboiler streams enhance the efficiency of the process, but complicate process modelling. The number of design variables is also augmented by additional degrees of freedom such as the location and the order of feeds, the number of stages and the reflux ratio in the column. The complexity of the demethaniser column precludes the use of the Fenske–Underwood–Gilliland shortcut design method. A semi-rigorous boundary value method is proposed for the design of complex demethaniser columns for application within an optimisation framework for process synthesis and evaluation. The results of the proposed design methodology are shown to be in good agreement with those of rigorous simulation. A simplified flowsheet simulation model based on a sequential modular approach is developed that is able to account for various configurations and inter-connections in the demethaniser process. Improved shortcut models for flash units, the turbo-expander, compressor and refrigeration cycle have been proposed for exploitation in a synthesis framework. A methodology accounting for heat integration in multistream exchangers is proposed. The simplified simulation model is applied for the optimisation of a flowsheet of fixed configuration. The nonlinear programming technique of sequential quadratic programming (SQP) is used as the optimisation method. A case study is presented to illustrate the application of the optimisation approach for maximising the annual profit. A generalised superstructure has been proposed for demethaniser flowsheet synthesis that includes various structural combinations in addition to the operational parameters. The various options included in the superstructure and their effects on flowsheet performance are discussed. A stochastic optimisation technique, simulated annealing, is applied to optimise the superstructure and generate energy-efficient and cost-effective flowsheets. The application of the developed synthesis methodology is illustrated by a case study of relevance to natural gas processing. The results allow insights to be obtained into the important trade-offs and interactions and indicate that the synthesis methodology can be employed as a tool for quantitative evaluation of preliminary designs as well as to facilitate evaluation, selection and optimisation of licensed demethaniser flowsheets.

This thesis was conducted to investigate the impacts of fiber composites on theenvironment. Composition, properties and application of fiber compositeswere also studied. On the basis of its application, taking into account previousstudies information was gathered related to impacts of these fiber composites.In order to study impacts of fiber composites in marine application a detailstudy was conducted where using the LCA method and Sima Pro softwarethree ship superstructures of the ship Stena Hollandica were compared. Thesewere steel superstructure, balsawood core superstructure and PVC foamsuperstructure. The results showed that over the lifecycle the impacts of PVCand balsawood superstructure were almost the same and were better than thesteel superstructure. The main contribution of impacts over the lifetime wasdue to the fuel consumed. When only the superstructure was consideredseparately from the life cycle the best choice was balsawood and the PVC foamsuperstructure had the most impacts. Overall it was found that balsawoodcould be considered as the best alternative as a material for the construction ofthis ship superstructure.

De nos jours, de nouvelles technologies sont développées pour produire efficacement des produits dérivés de matières premières autresque le pétrole, comme par exemple la biomasse. En effet, la biomasse et plus spécifiquement la biomasse non alimentaire possède un fort potentielcomme substitut aux ressources fossiles pour des raisons environnementales, économiques et politiques. Dans ce contexte, l’étude des bioraffineries offre de nouvelles opportunités pour le Process System Engineering et plus particulièrement pour des activités de recherche quivisent la conception de systèmes constitués d’entités interconnectés. En effet, le verrou principal se concentre sur la modélisation et l’optimisation multi-échelle de la bioraffinerie qui permet l’intégration de plusieurs échelles spatiales allant de l’échelle moléculaire à celle de l’unité de production. Ces différentes échelles sont essentielles pour décrire correctement le système puisqu’elles interagissent en permanence. La forte dilution des courants est le meilleur exemple pour illustrer ces interactions. En effet, la présence d’eau induit de nombreux problèmes thermodynamiques (azéotropes, etc.) à l’échelle moléculaire, ce qui impacte fortement la topologie du procédé notamment sur les étapes de séparation, de purification et detraitement des purges (pour limiter les pertes en produits). Ainsi, la performance de la séquence d’opérations unitaires de l’étape de purification dépend entièrement de la concentration en eau. De plus dans la conception de bioraffinerie, il est fréquent de coupler fermentation et séparation afin d’améliorer les performances de la fermentation et de limiter la présence d’eau dans l’étapede purification. Par ailleurs, la grande quantité d’eau à chauffer ou refroidir entraine la nécessité de réaliser l’intégration énergétique du réseaud’échangeurs du procédé afin de minimiser le coût les dépenses énergétiques. L’objectif de ce travail est alors de proposer une méthodologie générique et les outils associés afin de lever certains verrous de la modélisation et l’optimisation multi-échelle de la bioraffinerie. Basée sur une approche par superstructure, la finalité de la méthodologie est d’évaluer les performances des alternatives étudiées en termes technico-économiques, environnementaux et d’efficacité énergétique en vue de son optimisation multi-objectifs pour trouver la voie de traitement optimale pour le(s) bioproduit(s) d’intérêt. Le cas d’application retenu se focalise sur la production de biobutanol à partir du système Acétone-Butanol-Ethanolet d’une biomasse d’origine forestière. La première étape de la méthodologie proposée concerne la création de la superstructure de la bioraffineriebasée sur une décomposition de cette dernière en 5 étapes principales : le prétraitement, la fermentation, la séparation, la purification et letraitement des purges. Ensuite, la seconde étape consiste à modéliser chaque alternative de procédé. Cette modélisation utilise un modèlethermodynamique à coefficients d’activité afin de décrire le comportement fortement non-idéal des molécules du milieu. De plus, l’intégration du traitement des purges et de l’intégration énergétique durant cette étape permet d’améliorer le procédé. Enfin, la dernière étape s’intéresse à l’optimisation multiobjectif qui se focalise sur différents aspects : maximisation de la production, minimisation des coûts, du prix minimal de vente des bioproduits, des pertes en produits et de l’impact environnemental. Cette dernière étape inclut également des études de sensibilité sur les différents paramètres de la méthodologie : opératoires, économiques, environnementaux... A l’issu de l’optimisation, un compromis seratrouvé afin d’obtenir une bioraffinerie durable.

This thesis outlines the development of composite reinforcement technology for a ship's aluminium alloy superstructure. The work objective aimed to alleviate stress concentration in parts of the superstructure prone to fatigue-induced cracking. This is a novel approach to ship repair, which promises reduction in the cost of maintenance primarily due to greater efficiency and lower cost of repair. The work was conducted over approximately 12 years. It commenced in the late 80s with laboratory research and development and concluded in 2000 after completion of a seven-year trial on board a navy ship. Two carbon fibre composites, (5 m x 1 m consisting of a 25-ply laminate), were adhesively bonded to the 02-deck on the port and starboard sides. It was found that upgrading the structure using composites was effective, making it able to withstand service fatigue stresses. Finite element modelling and strain measurements on board the ship showed that critical stress concentration could be alleviated through stress redistribution. For the duration of the trial, no cracking of aluminium alloy deck in the vicinity of the reinforcements was reported. Both composite reinforcements exhibited good performance and remained in service after the end of the trial. However, the marine environment did cause some non-structural, edge debonding of the glass fibre reinforced overlay at the composite-metal interface. This overlay was designed to provide surface protection to the underlaying carbon reinforcement. Bond degradation was patchy. It occurred after about three years in service, most probably due to a combination of thermal cycling (solar heating/cooling) and water ingress at the interface. A new edge sealing method restored its durability and it required no further attention. This experiment was successfully demonstrated on board an active navy ship. The work proved that an effective and durable repair of a ship structure using non-metallic repair technology is feasible. Composite reinforcements prevented deck cracking and removed any need for welded repairs, thereby reducing the cost of ship maintenance. For further cost reduction it is recommended to adopt the principle of reverse engineering to simplify the technology for dockyard use.

This master´s thesis deals with the issue of purchase of the apartment from the perspective of an investor. The aim of the thesis is to evaluate the possible variants of purchase of the apartment, while the main attention is focused on a comparison of the acquisition of an existing apartment, which requires reconstruction, and on the possibility of the construction of a new apartment in the form of loft conversion or superstructure. Possible variants of the solution are discussed in a broader context in order to determine the optimal variant for the investor.

This thesis’s networked public sphere - the Civic Superstructure - transforms the public sphere by reconsidering the pace and purview of the civic. Contemporary public institutions are typically disconnected and isolated islands dispersed throughout the city. Our fast-paced, plugged-in lifestyle, however, is evermore inconsistent with such inconvenient geographical dispersal. By incorporating isolated public institutions into a networked system, this project provides a connective layer across an existing site and takes advantage of the interstitial zones between private institutions to offer the civic realm in places where you least expect it. This sprawling network acts as a platform for accessing public services and information, while also providing a new common space for the public to meet, to learn, to play and even to protest — in short, to be a public, even in this most unlikely of places rendered newly civic through a combination of digital and physical access.

Water consumption and wastewater generation depletes water resources and has a destructive impact on the environment. Recent attention has aimed at preserving water resources and preventing pollution through several routes. Restrictions on wastewater discharge into the environment, recycling, reuse and regeneration of wastewater streams are now common practices toward achieving these objectives. Membrane and integrated membrane processes have been shown to be effective at reducing water usage and recovering valuable compounds. This thesis focuses on topics related to the optimal synthesis of wastewater treatment networks by hybrid membrane systems. The use of superstructures has been a useful tool to synthesize chemical engineering process flowsheets. The approach postulates all possible alternatives of a potential treatment network. Within the representation, an optimal solution is assumed to be hidden in the given superstructure. State space is a framework to process synthesis problems which involves heat and mass exchange. In this representation, unit operations, utility units and utility streams can be embedded in such a way that all the process synthesis alternatives can be realized. Such a framework can be applied for water and wastewater synthesis problems. Several research optimization studies presented membrane and hybrid membrane process synthesis problems for wastewater treatment. Nonetheless, the problems in fact can be represented in several ways. Therefore, the mathematical programs are expected to be different for every postulated representation. Comparison between different representations and their mathematical programs are analyzed to highlight the relationship between the superstructure representation and their mathematical programming formulations. Possible improvement of these superstructures is addressed. Also, a generic representation is provided to give a systematic and clear description for assembling hybrid membrane system superstructures via the state space approach. The synthesis of reverse osmosis networks (RON) for water and wastewater treatment network is presented as a superstructure problem. The mathematical programming model describes the RON through a nonconvex mixed integer nonlinear program (MINLP). A mixed integer linear program (MILP) is derived based on the convex relaxation of the nonconvex terms in the MINLP to bound the global optimum. The MILP models are solved iteratively to supply different initial guesses for the nonconvex MINLP model. It is found that such a procedure is effective in finding local optimum solutions in reasonable time. Water desalination and treatment of aqueous wastes from the pulp and paper industry are considered as case studies to illustrate the solution strategy. The RON mathematical program is a nonconvex MINLP which contains several local optima. A deterministic branch and bound (B&B) algorithm to determine the global optimum for the RON synthesis problem has also been developed. A piecewise MILP is derived based on the convex relaxation of the nonconvex terms present in the MINLP formulation to approximate the original nonconvex program and to obtain a valid lower bound on the global optimum. The MILP model is solved at every node in the branch and bound tree to verify the global optimality of the treatment network within a pre-specified gap tolerance. Several constraints are developed to simultaneously screen the treatment network alternatives during the search, tighten the variable bounds and consequently accelerate algorithm convergence. Water desalination is considered as a case study to illustrate this approach for global optimization of the RO network. Wastewater and groundwater streams contaminated with volatile organic compounds (VOCs) require proper treatment to comply with discharge standards or drinking requirement restrictions. Air stripping and pervaporation are two common treatment technologies for water streams contaminated with VOCs. The combination of these technologies for water treatment which are representative of hybrid membrane systems may offer advantages over stand-alone treatments. Superstructure optimization uses the framework of hybridization to determine the optimal treatment network and the optimal operational requirements for the treatment units to achieve desired water qualities. Two case studies are presented to illustrate the proposed approach and sensitivity of the optimal solutions to given perturbations is analyzed.

Water consumption and wastewater generation depletes water resources and has a destructive impact on the environment. Recent attention has aimed at preserving water resources and preventing pollution through several routes. Restrictions on wastewater discharge into the environment, recycling, reuse and regeneration of wastewater streams are now common practices toward achieving these objectives. Membrane and integrated membrane processes have been shown to be effective at reducing water usage and recovering valuable compounds. This thesis focuses on topics related to the optimal synthesis of wastewater treatment networks by hybrid membrane systems. The use of superstructures has been a useful tool to synthesize chemical engineering process flowsheets. The approach postulates all possible alternatives of a potential treatment network. Within the representation, an optimal solution is assumed to be hidden in the given superstructure. State space is a framework to process synthesis problems which involves heat and mass exchange. In this representation, unit operations, utility units and utility streams can be embedded in such a way that all the process synthesis alternatives can be realized. Such a framework can be applied for water and wastewater synthesis problems. Several research optimization studies presented membrane and hybrid membrane process synthesis problems for wastewater treatment. Nonetheless, the problems in fact can be represented in several ways. Therefore, the mathematical programs are expected to be different for every postulated representation. Comparison between different representations and their mathematical programs are analyzed to highlight the relationship between the superstructure representation and their mathematical programming formulations. Possible improvement of these superstructures is addressed. Also, a generic representation is provided to give a systematic and clear description for assembling hybrid membrane system superstructures via the state space approach. The synthesis of reverse osmosis networks (RON) for water and wastewater treatment network is presented as a superstructure problem. The mathematical programming model describes the RON through a nonconvex mixed integer nonlinear program (MINLP). A mixed integer linear program (MILP) is derived based on the convex relaxation of the nonconvex terms in the MINLP to bound the global optimum. The MILP models are solved iteratively to supply different initial guesses for the nonconvex MINLP model. It is found that such a procedure is effective in finding local optimum solutions in reasonable time. Water desalination and treatment of aqueous wastes from the pulp and paper industry are considered as case studies to illustrate the solution strategy. The RON mathematical program is a nonconvex MINLP which contains several local optima. A deterministic branch and bound (B&B) algorithm to determine the global optimum for the RON synthesis problem has also been developed. A piecewise MILP is derived based on the convex relaxation of the nonconvex terms present in the MINLP formulation to approximate the original nonconvex program and to obtain a valid lower bound on the global optimum. The MILP model is solved at every node in the branch and bound tree to verify the global optimality of the treatment network within a pre-specified gap tolerance. Several constraints are developed to simultaneously screen the treatment network alternatives during the search, tighten the variable bounds and consequently accelerate algorithm convergence. Water desalination is considered as a case study to illustrate this approach for global optimization of the RO network. Wastewater and groundwater streams contaminated with volatile organic compounds (VOCs) require proper treatment to comply with discharge standards or drinking requirement restrictions. Air stripping and pervaporation are two common treatment technologies for water streams contaminated with VOCs. The combination of these technologies for water treatment which are representative of hybrid membrane systems may offer advantages over stand-alone treatments. Superstructure optimization uses the framework of hybridization to determine the optimal treatment network and the optimal operational requirements for the treatment units to achieve desired water qualities. Two case studies are presented to illustrate the proposed approach and sensitivity of the optimal solutions to given perturbations is analyzed.