Четверта міжнародна наукова-практична конференція «Комп’ютерне моделювання в хімії і технологіях та системах сталого розвитку»

Робота присвячена дослідженню робастності комбінаторного підходу до проектування та модернізації схем промислового підприємства, розробці методів підтримки проектних рішень при проектуванні технологічних схем водного господарства. Запропоновано критерії оцінювання процедур структурної оптимізації схем водного господарства. У відповідності до вказаних критеріїв запропоновано математичне забезпечення для процедури проектування схем водного господарстваThe work is devoted to investigation of robustness of combinatorial approach to the grassroot and retrofit design of industrial water networks. The evaluation criteria of procedures for structural optimization of water networks were proposed. According to the criteria the mathematical model procedures of water networks design was proposed.Работа посвящена исследованию робастности комбинаторного подхода к проектированию и модернизации схем промышленного предприятия, разработке методов поддержки проектных решений при проектировании технологических схем водного хозяйства. Предложены критерии оценки процедур структурной оптимизации схем водного хозяйства. В соответствии с указанными критериями предложено математическое обеспечение для процедуры проектирования схем водного хозяйства

Minimizing water and energy consumptions in water and heat exchange networks.

This study presents a mathematical programming formulation for the design of water and heat exchangers networks based on a two-step methodology. First, an MILP (mixed integer linear programming) procedure is used to solve the water and energy allocation problem regarding several objectives. The first step of the design method involves four criteria to be taken into account., ie, fresh water consumption (F1), energy consumption (F2), interconnection number (F3) and number of heat exchangers (F4). The multiobjective optimization Min [F1, F2] is solved by the so-called ɛ-constraint method and leads to several Pareto fronts for fixed numbers of connections and heat exchangers. The second step consists in improving the best results of the first phase with energy integration into the water network. This stage is solved by an MINLP procedure in order to minimize an objective cost function. Two examples reported in the dedicated literature serve as test bench cases to apply the proposed two-step approach. The results show that the simultaneous consideration of the abovementioned objectives is more realistic than the only minimization of fresh water consumption. Indeed, the optimal network does not necessarily correspond to the structure that reaches the fresh water target. For a real paper mill plant, energy consumption decreases of almost 20% as compared with previous studies

Industrial water management by multiobjective optimization: from individual to collective solution through eco-industrial parks.

Industrial water networks are designed in the first part by a multiobjective optimization strategy, where fresh water, regenerated water flow rates as well as the number of network connections (integer variables) are minimized. The problem is formulated as a Mixed-Integer Linear Programming problem (MILP) and solved by the ε-constraint method. The linearization of the problem is based on the necessary conditions of optimality defined by Savelski and Bagajewicz (2000). The approach is validated on a published example involving only one contaminant. In the second part the MILP strategy is implemented for designing an Eco-Industrial Park (EIP) involving three companies. Three scenarios are considered: EIP without regeneration unit, EIP where each company owns its regeneration unit and EIP where the three companies share regeneration unit(s). Three possible regeneration units can be chosen, and the MILP is solved under two kinds of conditions: limited or unlimited number of connections, same or different gains for each company. All these cases are compared according to the global equivalent cost expressed in fresh water and taking also into account the network complexity through the number of connections. The best EIP solution for the three companies can be determined

On the flexibility of an eco-industrial park (EIP) for managing industrial water

In a recent paper, a generic model, based on a multiobjective optimization procedure, for water supply system for a single company and for an eco-industrial park was proposed and illustrated by a park involving three companies A, B and C. The best configuration was identified by simultaneously minimizing the fresh water flow rate, the regenerated water flow rate and the number of connections in the eco-industrial park. The question is now to know what the maximal increase/decrease in pollutant flow rates is, so that the eco-industrial park remains feasible, economically profitable and environmentally friendly. A preliminary study shows that the park can accept an increase of pollutant flow rates of 29% in company A, 12% in company B and only 1% in company C; beyond these limits the industrial symbiosis becomes not feasible. The proposed configuration is not flexible with a very limited number of connections. Indeed, the solution implemented for conferring some flexibility to this network is to increase the number of connections within the park. However, connections have a cost, so the increase of their number needs to remain moderate. The number of connections is augmented until the symbiosis becomes unfeasible, or until the gain for each company to participate to the park becomes lower than a given threshold. Several cases are studied by increasing the pollutant flow rates under two different scenarios: 1) in only one company, 2) in two or three companies simultaneously

Оптимізація промислових схем водного господарства: структурний підхід

The research focuses on investigating the methods of analysis and design of industrial water networks (both water usage networks and water treatment networks) with the aim of intensifying the processes of waste water treatment as well as reducing natural water usage.Various mathematical models of water network components and networks as a whole from literature have been investigated. The peculiarities of the mathematical calculations are predetermined by the requirements to the models, namely, the necessity of stating the waste water streams composition by the known bulk losses and generally accepted assumptions and simplifications. Optimization criterion of technical and economic character has been calculated and proved to be most effective. The criterion for comparing different water networks optimization procedures has been proposed. The mathematical descriptions for the water networks optimization procedure on the basis of criterion mentioned has been suggested. The effectiveness of the conceptions and algorithms developed has been tested on a set of case studies from literary.Работа посвящена разработке методов поддержки проектных решений при проектировании технологических схем водного хозяйства промышленного предприятия: схем водопотребления, водоотведения и водоочистки.Разработаны критерии оценки процедур структурной оптимизации схем водного хозяйства. В соответствии с указанными критериями сформулировано математическое обеспечение для процедуры проектирования схем водного хозяйства. Испытания результатов исследования осуществлено на тестовом множестве литературных примеров.Робота присвячена розробці методів підтримки проектних рішень при проектуванні технологічних схем водного господарства промислового підприємства: схем водоспоживання, водовідведення та водоочищення. Розроблено критерії оцінювання процедур структурної оптимізації схем водного господарства. У відповідності до вказаних критеріїв сформульовано математичне забезпечення для процедури проектування схем водного господарства. Випробування результатів дослідження здійснене на тестовій множині прикладів літературних прикладі

Développement d'une bioraffinerie forestière intégrée et verte

L’économie du Canada dépend fortement de la vitalité de son secteur industriel qui est énergivore et émetteur de gaz à effet de serre. Dans un contexte de changement climatique, le Canada se doit de réagir. Cela passe entre autre par le développement des énergies renouvelables. Grâce à son industrie forestière, le Canada a tous les atouts nécessaires pour développer une bioéconomie dynamique. Le secteur de la foresterie inclut l’industrie des pâtes et papiers, une industrie qui fait face à une crise économique et doit donc se réinventer pour rester compétitive. Dans un tel contexte, le bioraffinage forestier qui consiste à valoriser les principaux constituants du bois pour la production aussi bien de produit de pâtes et papiers conventionnels que de produits chimiques de spécialité apparaît de plus en plus comme une solution offerte à l’industrie papetière pour faire face à la crise. Grace à ce concept, les papetières canadiennes seront en mesure de diversifier leur production et de regagner en compétitivité. Toutefois, transformer une usine de pâtes et papiers en une bioraffinerie intégrée est un exercice complexe associé à divers risques et incertitudes (ex., économique, technique, financier, etc). Il est de ce fait important de développer des outils qui permettent d’évaluer ces aspects afin que le concept de bioraffinage forestier devienne une réalité pour les papetières canadiennes. L’objectif principal de cette thèse est de démontrer la faisabilité technique et économique d’un nouveau concept de bioraffinerie forestière intégrée pour les usines de pâtes et papiers canadiennes qui n’utiliseraient aucune source d’énergie fossile sur site. Les défis à relever sont : (i) le développement d’une approche systématique qui permettrait de sélectionner les procédés de bioraffinage à intégrér, (ii) la proposition d’une méthodologie permettant d’atteindre un dégré d’intégration matérielle et énergétique suffisant entre les différents unités du complexe afin de substituer totalement le combustible. viii Pour ce faire, un nouveau concept de bioraffinerie forestière, le concept de bioraffinerie intégrée et verte a été développée. Ce concept repose sur le développement d’un complexe; centré autour d’une usine de pâtes et papiers; parfaitement intégré et bouclé dont l’empreinte écologique est réduite au maximum par l’implantation stratégique de procédés de conversion de la biomasse pour la production de bioproduits variés. Une bioraffinerie intégrée et verte comprend quatre unités : (i) une usine de pâtes et papiers, (ii) une bioraffinerie pour la production d’un bioproduit, (iii) une unité de gazéification de la biomasse pour la production de gaz de synthèse utilisé en remplacement du gaz naturel employé dans le four à chaux de l’usine de pâtes et papiers et (iv) une unité de polygénération pour la production de chaleur, de refroidissement et d’électricité. Une bioraffinerie intégrée et verte a une balance environnementale positive. Dans un tel complexe, la consommation d’eau fraiche et la production d’effluents sont réduites au maximum. Les émissions de gaz à effet de serre sont également contrôlées et plus important, une bioraffinerie intégrée et verte ne consomme aucune énergie fossile. Une stratégie d’implantation pour développer durablement une bioraffinerie intégrée et verte a été proposée et consiste en 5 étapes : (i) sélection de l’usine de P&P réceptrice, (ii) sélection de la bioraffinerie, (iii) intégration matérielle et énergétique des différents procédés suivie de (iv) l’implantation d’une unité de gazéification de la biomasse et (v) d’une unité de polygénération. Une nouvelle méthodologie, basée sur la programmation mathématique, pour l’optimisation matérielle et énegétique de la bioraffinerie intégrée a été proposée. La méthodologie est innovante de part la formulation du problème d’allocation des réseaux d’eau adoptée puisqu’elle prend en compte les spécificités d’une usine de pâtes à papiers telle l’existance de points de transfert thermique direct qui affectent l’éfficacité énergétique de l’usine de P&P. La prise en compte de ces particularités du procédé de mise en pâte lors de la définition ix du problème d’allocation des réseaux d’eau résulte en la réduction simultanée des consommations d’eau et de vapeur du procédé. La formulation du problème sous forme de problème mixte à variable entières intégrées est particulièrement intéressante puisqu’il conduit à une multitude de solutions lors de sa résolution. Les solutions obtenues, présentées sous formes de front de Pareto, sont toutes équvalentes d’un point de vue mathématique. C’est l’utilisateur qui intervient et prend la décision finale quant à la solution optimale à considérer pour futures modifications des réseaux d’échangeurs d’eau et de chaleur de la bioraffinerie intégrée. Le choix de la solution se base, aussi bien sur les connaissances du procédé en termes de contraintes, que sur des régles de bases d’ingéniérie. Cette étape de sélection de la solution optimale peut également s’effectuer grâce à un outil de prise de décision. Le concept et la méthodologie d’implantation proposés ont été testés sur des études de cas impliquant la conversion d’une usine de pâte dissoute en bioraffinerie intégrée et verte pour la production de furfural ou d’éthanol. Les résultats obtenus démontrent que le concept de bioraffinerie intégrée et verte est un nouveau concept qui est techniquement faisable si le dégré d’intégration entre l’usine de pâtes et papiers et les autres procédés constituants le complexe est optimal et économiquement rentable si les technologies de conversion de la biomasse vise la synthèse d’un produit chimique de spécialité soit à très haute valeur ajoutée. La méthodologie d’intégration matérielle et énergétique dévelopée, en plus d’être innovante, est robutste, pratique et efficace. En comparaison avec les méthodologies proposées dans la littérature pour l’optimisation simulatanée de l’eau et de l’énegie, la nouvelle méthodologie est interactive, car elle se base sur la formulation multi-objectifs du problème conduisant à plusieurs solutions lors de la résolution.------------ Canada's economy depends strongly on the vitality of its industrial sector which is energy intensive and emitter of greenhouse gases. In the context of climate change, Canada must react by developing its renewable energy sector. With its strong forest industry, Canada can play an important role in the development of a world bioeconomy. The forestry sector includes the pulp and paper industry, an industry facing an important economic crisis during the last years. As a response, the pulp and paper industry needs to reinvent itself in order to remain competitive. In such a context, the forest biorefinery concept which consists in valorizing the main components of wood, for the production of both conventional pulp and paper products and specialty chemicals appears to be one solution for the pulp and paper industry to cope with the crisis. Thanks to this concept, the Canadian pul mills will be able to diversify their production and regain competitiveness. The main objective of this thesis is then to propose and demonstrate the technical and economic feasibility of a new integrated forest biorefinery concept for Canadian pulp and paper mills targeted toward the development of a fossil fuel free facility. The challenges to be addressed are: (i) the development of systematic approaches to select the biorefinery processes to be implemented; (ii) the development of a mass and energy integration methodology that will allow the establishement of a site with no fossil fuel consumption. A new forest biorefinery concept, the green integrated forest biorefinery has been developed. This concept is based on the development of a complex, centered around a pulp and paper mill, fully integrated whose ecological footprint is reduced to the minimum through the strategic implementation of biomass conversion processes for the production of various bioproducts. A green integrated forest biorefinery includes 4 units: (i ) a pulp and paper mill which is the core of the complex, (ii) a biorefinery for the production of bio-products , (iii) a biomass gasification unit xi for production of syngas used to substitute natural gas usage on-site and ( iv ) a polygeneration unit generating green power and supplying cooling and heating to the integrated facility. The green integrated forest biorefinery is environmentally friendly. In such a facility, fresh water consumption, effluent production and greenhouse gases emissions are reduced to their minimum. But most importantly, a green integrated forest biorefinery is a fossil fuel free facility. An implementation strategy to develop a sustainable green integrated forest biorefinery has been proposed and consists of five steps: (i) selection of the receptor pulp mill and (ii) biorefinery plant, (iii) intense material and energy integration of the various processes followed by (iv) the implantation of biomass gasification and (v) a polygeneration units. A new mathematical-based optimization methodology for simultaneous reduction of water and energy consumption has been developed. The methodology takes into account the interconnection between water and steam consumption in a pulp and paper mill by taking into account the presence of stream mixing point that affects the energy efficiencies and the steam consumption of the overall process. The formulation as a MILP problem is particularly interesting and differs from what has been reported in the literature for combined mass and energy optimization problem as it gives multiple solutions during the resolution phase in the form of a Pareto front. The user takes the final decision regarding the solution to be further implemented within the process based on its knowledge of the process and pratical engineering rules. The decision making process can be facilitated using specific tools. The concept and implementation methodology proposed have been applied to case studies involving the conversion of a dissolved pulp mill into a green integrated forest biorefinery for the production of furfural and ethanol. xii The results show that the concept of green integrated forest biorafinery is an innovative concept that is technically feasible, providing an optimal energy and mass integration between the different constituents of the facility and economically viable if the integrated forest biorefinery is targeted for the production of specialty chemicals. The proposed mass and energy integration methodology is innovative, robust and efficient. In addition, it is interactive since the user plays a key role in the decision making process to select the optimum solutio

Advanced oxidation process models for optimisation and decision making support in water management

The objective of this thesis is contributing to the development of a systematic modelling approach for a more efficient and sustainable water management. The main aim is introducing Chemical and Process System Engineering methods and tools to provide a contribution to the AOPs (Advanced Oxidation Processes) investigation field by proposing process models that can be exploited to progress towards efficient management strategies for practical AOPs operation and inclusion in wastewater treatment networks. First, different advanced oxidation processes, namely Fenton, photo-Fenton and VUV photo-oxidation, were investigated and compared for the treatment of paracetamol (PCT) aqueous solution, by evaluating a series of performance indicators. Among the selected AOPs, VUV photo-oxidation and photo-Fenton showed the most promising results. Both processes allowed attaining total removal of the target compound and high mineralization levels. The second and main part of the thesis was focused on transforming “data into knowledge” by proposing different modelling approaches. The modelling effort focused on Fenton/photo-Fenton processes that showed the need of improving operating conditions. Accordingly, two practical kinetic models for Fenton and photo-Fenton degradation of organic compounds have been proposed and validated: • A conventional First Principles Model, based on a line source radiation model with spherical and isotropic emission, developed for the prediction of Fenton and photo-Fenton degradation of PCT and the oxidant (H2O2) consumption; • A general non-conventional First Principles Model, based on a wide-ranging contaminant degradation mechanism considering a variable number of carbon atoms for the characterization of the intermediates. Both models were experimentally validated and showed that were able to satisfactorily reproduce the system behavior. Particularly, the non-conventional First Principles Model showed to be a successful modelling approach for the Fenton/photo-Fenton degradation of different wastewater systems composed by single or multiple organic contaminants by means of lumped parameters (e.g. Total Organic Carbon-TOC). Thus, the approach proved to offer practical characterization of complex mixtures of chemicals. Once process models are proposed and validated, they can be systematically exploited to determine efficient operation modes or design alternatives. Accordingly, the thesis addressed two cases of practical interest: the optimization of a control recipe and the design of a treatment network. Particularly, a dynamic optimization framework for taking advantage of available kinetic models and determining the best hydrogen peroxide dosage profile, was proposed. Economic and environmental objectives and constraints were included to develop a dynamic optimization problem that was implemented in JModelica and solved using a direct simultaneous optimization method (IPOPT). Finally, the combination of cheaper conventional biological processes with more expensive AOPs was explored. A Mixed-Integer Non Linear Programming (MINLP) model for the optimization of a general wastewater network was proposed based on a superstructure of alternative designs, which was implemented and solved in GAMS. The novel formulation includes the BOD5/COD ratio method, describing the removal efficiency of BOD5 and COD of a treatment for modelling the variation of the biodegradability of the influents. This novel formulation allows determining the extent of the AOP treatments when combined with biological treatments, and paves the way for more complex models aimed at solving the trade-off between cost and treatment efficiency.El objetivo de esta tesis es contribuir al desarrollo de técnicas de modelado sistemático para una gestión del agua eficiente y sostenible. El objetivo principal es contribuir a la investigación de los PAOs (Procesos Avanzados de Oxidación). La tesis introduce métodos y herramientas de Ingeniería de Procesos Químicos y propone modelos que puedan ser explotados para producir estrategias eficientes de gestión y operación de los PAOs, así como para la integración de estos PAOs en redes de tratamiento de aguas residuales. Primero, se investigaron diferentes PAOs. Se consideraron los procesos Fenton, foto-Fenton y la foto-oxidación VUV, y se compararon en el tratamiento de soluciones acuosas de paracetamol (PCT) adoptando una serie de indicadores de rendimiento (Key Performance Indicators, KPI). Entre los PAOs seleccionados, la foto-oxidación VUV y foto-Fenton producieron los resultados más prometedores, permitiendo lograr la eliminación total del contaminante y alto nivel de mineralización. La segunda parte de la tesis se centró en transformar ¿datos en conocimiento¿ mediante la propuesta de modelos para los procesos Fenton / photo-Fenton con el fin de mejorar las condiciones operativas de los mismos. En concreto se han propuesto y validado dos modelos cinéticos que describen la degradación de compuestos orgánicos por procesos Fenton y foto-Fenton: ¿ Un Modelo de Principios Básicos (F convencional, que incluye la modelización de la radiación lineal con emisión esférica e isotrópica, desarrollado para predecir la degradación Fenton y foto-Fenton del PCT y el consumo de oxidante (H2O2); ¿ Un Modelo de Principios Básicos no convencional, que propone un mecanismo de degradación de contaminantes general puesto que considera el número de átomos de carbono del contaminante como la variable de partida para la propuesta de fragmentación y consiguiente generación de intermedios. Ambos modelos se validaron experimentalmente y mostraron reproducir satisfactoriamente el comportamiento del sistema. En particular, el Modelo de Principios Básicos no convencional genero resultados prometedores para la degradación Fenton / foto-Fenton de diferentes sistemas (compuestos por uno o más contaminantes orgánicos) por medio de parámetros globales (como el Carbono Orgánico Total). Por tanto, este enfoque ofrece un modelado práctico independiente del contaminante y válido para mezclas complejas de productos químicos. Una vez propuestos y validados, los modelos de proceso se pueden utilizar sistemáticamente para determinar modos de operación eficientes o alternativas de diseño. En consecuencia, la tesis se dirigió a dos casos de interés práctico: la optimización de una receta de control y el diseño de una red de tratamiento. En el primer caso, se propuso una estrategia de optimización dinámica para aprovechar los modelos cinéticos disponibles y determinar el mejor perfil de dosificación de peróxido de hidrógeno. Se incluyeron objetivos y limitaciones económicas y ambientales para desarrollar un problema de optimización dinámica que se implementó en JModelica y se resolvió utilizando un método de optimización simultánea directa (IPOPT). Finalmente, se exploró la combinación de procesos biológicos convencionales, más baratos, con PAOs, más costosos. Se propuso un modelo de Programación no Lineal de Enteros Mixtos (MINLP) para la optimización de una red general de aguas residuales, basado en una superestructura de diseños alternativos, que se implementó y resolvió en GAMS. La nueva formulación incluye la relación BOD5 / COD, que describe la eficiencia de eliminación de BOD5 y COD de un tratamiento con el fin de modelar la variación de la biodegradabilidad de los influentes. Esta novedosa formulación permite determinar el alcance de los tratamientos de PAOs cuando se combinan con tratamientos biológicos, y allana el camino para modelos más complejos destinados a resolver el equilibrio entre coste y eficiencia del tratamiento.L'objectiu d'aquesta tesi és contribuir al desenvolupament de tècniques de modelatge sistemàtic per a una gestió de l'aigua eficient i sostenible. L'objectiu principal és contribuir a la investigació dels PAOs (Processos Avançats d'Oxidació). La tesi introdueix mètodes i eines d'Enginyeria de Processos Químics i proposa models que puguin ser explotats per produir estratègies eficients de gestió i operació dels PAOs, així com per a la integració d'aquests PAOs en xarxes de tractament d'aigües residuals. Primer, es van investigar diferents PAOs. Es van considerar els processos Fenton, foto-Fenton i la foto-oxidació VUV, i es van comparar en el tractament de solucions aquoses de paracetamol (PCT) adoptant una sèrie d'indicadors de rendiment (Key Performance Indicators, KPI). Entre els PAOs seleccionats, la foto-oxidació VUV i foto-Fenton van produir els resultats més prometedors, permetent aconseguir l'eliminació total del contaminant i alt nivell de mineralització. La segona part de la tesi es va centrar en transformar "dades en coneixement" mitjançant la proposta de models per als processos Fenton / photo-Fenton amb la finalitat de millorar les condicions operatives dels mateixos. En concret, s’han proposat i validat dos models cinètics que descriuen la degradació de compostos orgànics per processos Fenton i foto-Fenton: • Un model de Principis Bàsics convencional, que inclou la modelització de la radiació lineal amb emissió esfèrica i isotròpica, desenvolupat per predir la degradació Fenton i foto-Fenton del PCT i el consum d'oxidant (H2O2); • Un model de Principis Bàsics no convencional que proposa un mecanisme de degradació de contaminants general, ja que considera el nombre d'àtoms de carboni del contaminant com la variable de partida per a la proposta de fragmentació i consegüent generació d'intermedis. Tots dos models es van validar experimentalment i van mostrar la seva capacitat de reproduir satisfactòriament el comportament del sistema. En particular, el Model de Principis Bàsics no convencional ha generat resultats prometedors per a la degradació Fenton / foto-Fenton de diferents sistemes (compostos per un o més contaminants orgànics) per mitjà de paràmetres globals (com el Carboni Orgànic Total). Per tant, aquest enfocament ofereix un modelatge pràctic, independent del contaminant i vàlid per a mescles complexes de productes químics. Un cop proposats i validats, els models de procés es poden utilitzar sistemàticament per determinar maneres d'operació eficients o alternatives de disseny. En conseqüència, la tesi es va dirigir a dos casos d'interès pràctic: l'optimització d'una recepta de control i el disseny d'una xarxa de tractament. En el primer cas, es va proposar una estratègia d'optimització dinàmica per aprofitar els models cinètics disponibles i determinar el millor perfil de dosificació de peròxid d'hidrogen. Es van incloure objectius i limitacions econòmiques i ambientals per desenvolupar un problema d'optimització dinàmica que es va implementar en JModelica i es va resoldre utilitzant un mètode d'optimització simultània directa (IPOPT). Finalment, es va explorar la combinació de processos biològics convencionals, més barats, amb PAOs, més costosos. Es va proposar un model de Programació No Lineal Entera Mixta (MINLP) per a l'optimització d'una xarxa general d'aigües residuals, basat en una superestructura de dissenys alternatius, que es va implementar i resoldre en GAMS. La nova formulació inclou la relació BOD5 / COD, que descriu l'eficiència d'eliminació de BOD5 i COD d'un tractament per tal de modelar la variació de la biodegradabilitat dels influents. Aquesta nova formulació permet determinar l'abast dels tractaments de PAOs quan es combinen amb tractaments biològics, i aplana el camí per a models més complexos destinats a resoldre l'equilibri entre cost i eficiència del tractament.L'obiettivo della presente tesi è contribuire allo sviluppo di tecniche di modellizzazione sistematica finalizzate ad una gestione efficiente e sostenibile delle risorse idriche. L'obiettivo principale è contribuire allo studio dei POA (Processi di Ossidazione Avanzata). La tesi introduce metodi e strumenti dell’ingegneria dei processi chimici e propone modelli che possano servire per lo sviluppo di strategie efficaci di gestione dei POA nonché per l'integrazione di questi ultimi nelle reti di trattamento delle acque reflue. In primo luogo, sono stati studiati diversi POA. Nello specifico, sono stati studiati i processi di foto-ossidazione Fenton, photo-Fenton e VUV per il trattamento di soluzioni acquose di paracetamolo (PCT) la cui efficacia è stata confrontata adottando una serie di indicatori di prestazione (Key Performance Indicators, KPI). Tra i POA selezionati, la foto-ossidazione VUV e il processo photo-Fenton hanno prodotto i risultati più promettenti, consentendo di ottenere l'eliminazione totale del contaminante e un alto livello di mineralizzazione. La seconda parte della tesi si è concentrata sulla trasformazione dei "dati in conoscenza" proponendo modelli finalizzati alla descrizione dei processi Fenton / photo-Fenton e con l’obiettivo ultimo di adoperarli per ottimizzare le condizioni operative di questi ultimi. In particolare, sono stati proposti e validati due modelli cinetici che descrivono la degradazione dei composti organici per mezzo dei processi Fenton e photo-Fenton: • Un modello convenzionale, che include la modellizzazione della radiazione basata sull’ipotesi di radiazione lineare ed emissione sferica e isotropica, e in grado di prevedere la degradazione del PCT ad opera dei processi Fenton e photo-Fenton nonché il consumo di ossidante (H2O2); • Un modello non convenzionale, che propone un meccanismo generale di degradazione degli inquinanti basato sul numero di atomi di carbonio del contaminante da degradare a partire dal quale si propone un meccanismo di frammentazione di quest’ultimo con conseguente generazione di prodotti intermedi. Entrambi i modelli sono stati validati sperimentalmente e hanno mostrato prestazioni soddisfacenti. In particolare, il modello non convenzionale ha mostrato di poter rappresentare la degradazione Fenton e photo-Fenton di diversi composti organici attraverso l’utilizzo di un parametro globale (come il carbonio organico totale) e qindi di offrire una proposta di modellizzazione pratica indipendente dal contaminante e che può pertanto essere adottata in caso di miscele complesse di prodotti chimici. Una volta proposti e convalidati, i modelli di processo possono essere utilizzati sistematicamente per determinare modalità operative efficienti o alternative di progettazione. Di conseguenza, la tesi ha affrontato due casi di interesse pratico: l'ottimizzazione della ricetta di controllo del processo e la progettazione di una rete di trattamento di acque reflue. Nel primo caso è stata proposta una strategia di ottimizzazione dinamica per sfruttare i modelli cinetici disponibili e determinare il miglior profilo di dosaggio del perossido di idrogeno. Sono stati inclusi obiettivi e limiti economici e ambientali per sviluppare un problema di ottimizzazione dinamica implementato in JModelica che è stato risolto utilizzando un metodo di ottimizzazione simultanea diretta (IPOPT). Infine, è stata esplorata la combinazione di processi biologici convenzionali, più economici, con i PAO, più costosi. È stato proposto un modello MINLP (Nonlinear Mixed Integer Programming) per l'ottimizzazione di una rete di acque reflue, basato su una struttura attraverso la quale è possibile rappresentare scelte progettuali alternative, che è stato implementato e risolto in GAMS. La nuova formulazione include il rapporto BOD5 / COD, che descrive l'efficienza di eliminazione di BOD5 e COD di un trattamento al fine di modellare la variazione della biodegradabilità degli influenti. Questa nuova formulazione consente di determinare le diverse possibilità di combinazione dei PAO con i trattamenti biologici e apre la strada a modelli più complessi volti a risolvere l'equilibrio tra costo ed efficienza del trattamento

Advanced oxidation process models for optimisation and decision making support in water management

Aplicat embargament des de la data de defensa fins a l'abril de 2019The objective of this thesis is contributing to the development of a systematic modelling approach for a more efficient and sustainable water management. The main aim is introducing Chemical and Process System Engineering methods and tools to provide a contribution to the AOPs (Advanced Oxidation Processes) investigation field by proposing process models that can be exploited to progress towards efficient management strategies for practical AOPs operation and inclusion in wastewater treatment networks. First, different advanced oxidation processes, namely Fenton, photo-Fenton and VUV photo-oxidation, were investigated and compared for the treatment of paracetamol (PCT) aqueous solution, by evaluating a series of performance indicators. Among the selected AOPs, VUV photo-oxidation and photo-Fenton showed the most promising results. Both processes allowed attaining total removal of the target compound and high mineralization levels. The second and main part of the thesis was focused on transforming “data into knowledge” by proposing different modelling approaches. The modelling effort focused on Fenton/photo-Fenton processes that showed the need of improving operating conditions. Accordingly, two practical kinetic models for Fenton and photo-Fenton degradation of organic compounds have been proposed and validated: • A conventional First Principles Model, based on a line source radiation model with spherical and isotropic emission, developed for the prediction of Fenton and photo-Fenton degradation of PCT and the oxidant (H2O2) consumption; • A general non-conventional First Principles Model, based on a wide-ranging contaminant degradation mechanism considering a variable number of carbon atoms for the characterization of the intermediates. Both models were experimentally validated and showed that were able to satisfactorily reproduce the system behavior. Particularly, the non-conventional First Principles Model showed to be a successful modelling approach for the Fenton/photo-Fenton degradation of different wastewater systems composed by single or multiple organic contaminants by means of lumped parameters (e.g. Total Organic Carbon-TOC). Thus, the approach proved to offer practical characterization of complex mixtures of chemicals. Once process models are proposed and validated, they can be systematically exploited to determine efficient operation modes or design alternatives. Accordingly, the thesis addressed two cases of practical interest: the optimization of a control recipe and the design of a treatment network. Particularly, a dynamic optimization framework for taking advantage of available kinetic models and determining the best hydrogen peroxide dosage profile, was proposed. Economic and environmental objectives and constraints were included to develop a dynamic optimization problem that was implemented in JModelica and solved using a direct simultaneous optimization method (IPOPT). Finally, the combination of cheaper conventional biological processes with more expensive AOPs was explored. A Mixed-Integer Non Linear Programming (MINLP) model for the optimization of a general wastewater network was proposed based on a superstructure of alternative designs, which was implemented and solved in GAMS. The novel formulation includes the BOD5/COD ratio method, describing the removal efficiency of BOD5 and COD of a treatment for modelling the variation of the biodegradability of the influents. This novel formulation allows determining the extent of the AOP treatments when combined with biological treatments, and paves the way for more complex models aimed at solving the trade-off between cost and treatment efficiency.El objetivo de esta tesis es contribuir al desarrollo de técnicas de modelado sistemático para una gestión del agua eficiente y sostenible. El objetivo principal es contribuir a la investigación de los PAOs (Procesos Avanzados de Oxidación). La tesis introduce métodos y herramientas de Ingeniería de Procesos Químicos y propone modelos que puedan ser explotados para producir estrategias eficientes de gestión y operación de los PAOs, así como para la integración de estos PAOs en redes de tratamiento de aguas residuales. Primero, se investigaron diferentes PAOs. Se consideraron los procesos Fenton, foto-Fenton y la foto-oxidación VUV, y se compararon en el tratamiento de soluciones acuosas de paracetamol (PCT) adoptando una serie de indicadores de rendimiento (Key Performance Indicators, KPI). Entre los PAOs seleccionados, la foto-oxidación VUV y foto-Fenton producieron los resultados más prometedores, permitiendo lograr la eliminación total del contaminante y alto nivel de mineralización. La segunda parte de la tesis se centró en transformar ¿datos en conocimiento¿ mediante la propuesta de modelos para los procesos Fenton / photo-Fenton con el fin de mejorar las condiciones operativas de los mismos. En concreto se han propuesto y validado dos modelos cinéticos que describen la degradación de compuestos orgánicos por procesos Fenton y foto-Fenton: ¿ Un Modelo de Principios Básicos (F convencional, que incluye la modelización de la radiación lineal con emisión esférica e isotrópica, desarrollado para predecir la degradación Fenton y foto-Fenton del PCT y el consumo de oxidante (H2O2); ¿ Un Modelo de Principios Básicos no convencional, que propone un mecanismo de degradación de contaminantes general puesto que considera el número de átomos de carbono del contaminante como la variable de partida para la propuesta de fragmentación y consiguiente generación de intermedios. Ambos modelos se validaron experimentalmente y mostraron reproducir satisfactoriamente el comportamiento del sistema. En particular, el Modelo de Principios Básicos no convencional genero resultados prometedores para la degradación Fenton / foto-Fenton de diferentes sistemas (compuestos por uno o más contaminantes orgánicos) por medio de parámetros globales (como el Carbono Orgánico Total). Por tanto, este enfoque ofrece un modelado práctico independiente del contaminante y válido para mezclas complejas de productos químicos. Una vez propuestos y validados, los modelos de proceso se pueden utilizar sistemáticamente para determinar modos de operación eficientes o alternativas de diseño. En consecuencia, la tesis se dirigió a dos casos de interés práctico: la optimización de una receta de control y el diseño de una red de tratamiento. En el primer caso, se propuso una estrategia de optimización dinámica para aprovechar los modelos cinéticos disponibles y determinar el mejor perfil de dosificación de peróxido de hidrógeno. Se incluyeron objetivos y limitaciones económicas y ambientales para desarrollar un problema de optimización dinámica que se implementó en JModelica y se resolvió utilizando un método de optimización simultánea directa (IPOPT). Finalmente, se exploró la combinación de procesos biológicos convencionales, más baratos, con PAOs, más costosos. Se propuso un modelo de Programación no Lineal de Enteros Mixtos (MINLP) para la optimización de una red general de aguas residuales, basado en una superestructura de diseños alternativos, que se implementó y resolvió en GAMS. La nueva formulación incluye la relación BOD5 / COD, que describe la eficiencia de eliminación de BOD5 y COD de un tratamiento con el fin de modelar la variación de la biodegradabilidad de los influentes. Esta novedosa formulación permite determinar el alcance de los tratamientos de PAOs cuando se combinan con tratamientos biológicos, y allana el camino para modelos más complejos destinados a resolver el equilibrio entre coste y eficiencia del tratamiento.L'objectiu d'aquesta tesi és contribuir al desenvolupament de tècniques de modelatge sistemàtic per a una gestió de l'aigua eficient i sostenible. L'objectiu principal és contribuir a la investigació dels PAOs (Processos Avançats d'Oxidació). La tesi introdueix mètodes i eines d'Enginyeria de Processos Químics i proposa models que puguin ser explotats per produir estratègies eficients de gestió i operació dels PAOs, així com per a la integració d'aquests PAOs en xarxes de tractament d'aigües residuals. Primer, es van investigar diferents PAOs. Es van considerar els processos Fenton, foto-Fenton i la foto-oxidació VUV, i es van comparar en el tractament de solucions aquoses de paracetamol (PCT) adoptant una sèrie d'indicadors de rendiment (Key Performance Indicators, KPI). Entre els PAOs seleccionats, la foto-oxidació VUV i foto-Fenton van produir els resultats més prometedors, permetent aconseguir l'eliminació total del contaminant i alt nivell de mineralització. La segona part de la tesi es va centrar en transformar "dades en coneixement" mitjançant la proposta de models per als processos Fenton / photo-Fenton amb la finalitat de millorar les condicions operatives dels mateixos. En concret, s’han proposat i validat dos models cinètics que descriuen la degradació de compostos orgànics per processos Fenton i foto-Fenton: • Un model de Principis Bàsics convencional, que inclou la modelització de la radiació lineal amb emissió esfèrica i isotròpica, desenvolupat per predir la degradació Fenton i foto-Fenton del PCT i el consum d'oxidant (H2O2); • Un model de Principis Bàsics no convencional que proposa un mecanisme de degradació de contaminants general, ja que considera el nombre d'àtoms de carboni del contaminant com la variable de partida per a la proposta de fragmentació i consegüent generació d'intermedis. Tots dos models es van validar experimentalment i van mostrar la seva capacitat de reproduir satisfactòriament el comportament del sistema. En particular, el Model de Principis Bàsics no convencional ha generat resultats prometedors per a la degradació Fenton / foto-Fenton de diferents sistemes (compostos per un o més contaminants orgànics) per mitjà de paràmetres globals (com el Carboni Orgànic Total). Per tant, aquest enfocament ofereix un modelatge pràctic, independent del contaminant i vàlid per a mescles complexes de productes químics. Un cop proposats i validats, els models de procés es poden utilitzar sistemàticament per determinar maneres d'operació eficients o alternatives de disseny. En conseqüència, la tesi es va dirigir a dos casos d'interès pràctic: l'optimització d'una recepta de control i el disseny d'una xarxa de tractament. En el primer cas, es va proposar una estratègia d'optimització dinàmica per aprofitar els models cinètics disponibles i determinar el millor perfil de dosificació de peròxid d'hidrogen. Es van incloure objectius i limitacions econòmiques i ambientals per desenvolupar un problema d'optimització dinàmica que es va implementar en JModelica i es va resoldre utilitzant un mètode d'optimització simultània directa (IPOPT). Finalment, es va explorar la combinació de processos biològics convencionals, més barats, amb PAOs, més costosos. Es va proposar un model de Programació No Lineal Entera Mixta (MINLP) per a l'optimització d'una xarxa general d'aigües residuals, basat en una superestructura de dissenys alternatius, que es va implementar i resoldre en GAMS. La nova formulació inclou la relació BOD5 / COD, que descriu l'eficiència d'eliminació de BOD5 i COD d'un tractament per tal de modelar la variació de la biodegradabilitat dels influents. Aquesta nova formulació permet determinar l'abast dels tractaments de PAOs quan es combinen amb tractaments biològics, i aplana el camí per a models més complexos destinats a resoldre l'equilibri entre cost i eficiència del tractament.L'obiettivo della presente tesi è contribuire allo sviluppo di tecniche di modellizzazione sistematica finalizzate ad una gestione efficiente e sostenibile delle risorse idriche. L'obiettivo principale è contribuire allo studio dei POA (Processi di Ossidazione Avanzata). La tesi introduce metodi e strumenti dell’ingegneria dei processi chimici e propone modelli che possano servire per lo sviluppo di strategie efficaci di gestione dei POA nonché per l'integrazione di questi ultimi nelle reti di trattamento delle acque reflue. In primo luogo, sono stati studiati diversi POA. Nello specifico, sono stati studiati i processi di foto-ossidazione Fenton, photo-Fenton e VUV per il trattamento di soluzioni acquose di paracetamolo (PCT) la cui efficacia è stata confrontata adottando una serie di indicatori di prestazione (Key Performance Indicators, KPI). Tra i POA selezionati, la foto-ossidazione VUV e il processo photo-Fenton hanno prodotto i risultati più promettenti, consentendo di ottenere l'eliminazione totale del contaminante e un alto livello di mineralizzazione. La seconda parte della tesi si è concentrata sulla trasformazione dei "dati in conoscenza" proponendo modelli finalizzati alla descrizione dei processi Fenton / photo-Fenton e con l’obiettivo ultimo di adoperarli per ottimizzare le condizioni operative di questi ultimi. In particolare, sono stati proposti e validati due modelli cinetici che descrivono la degradazione dei composti organici per mezzo dei processi Fenton e photo-Fenton: • Un modello convenzionale, che include la modellizzazione della radiazione basata sull’ipotesi di radiazione lineare ed emissione sferica e isotropica, e in grado di prevedere la degradazione del PCT ad opera dei processi Fenton e photo-Fenton nonché il consumo di ossidante (H2O2); • Un modello non convenzionale, che propone un meccanismo generale di degradazione degli inquinanti basato sul numero di atomi di carbonio del contaminante da degradare a partire dal quale si propone un meccanismo di frammentazione di quest’ultimo con conseguente generazione di prodotti intermedi. Entrambi i modelli sono stati validati sperimentalmente e hanno mostrato prestazioni soddisfacenti. In particolare, il modello non convenzionale ha mostrato di poter rappresentare la degradazione Fenton e photo-Fenton di diversi composti organici attraverso l’utilizzo di un parametro globale (come il carbonio organico totale) e qindi di offrire una proposta di modellizzazione pratica indipendente dal contaminante e che può pertanto essere adottata in caso di miscele complesse di prodotti chimici. Una volta proposti e convalidati, i modelli di processo possono essere utilizzati sistematicamente per determinare modalità operative efficienti o alternative di progettazione. Di conseguenza, la tesi ha affrontato due casi di interesse pratico: l'ottimizzazione della ricetta di controllo del processo e la progettazione di una rete di trattamento di acque reflue. Nel primo caso è stata proposta una strategia di ottimizzazione dinamica per sfruttare i modelli cinetici disponibili e determinare il miglior profilo di dosaggio del perossido di idrogeno. Sono stati inclusi obiettivi e limiti economici e ambientali per sviluppare un problema di ottimizzazione dinamica implementato in JModelica che è stato risolto utilizzando un metodo di ottimizzazione simultanea diretta (IPOPT). Infine, è stata esplorata la combinazione di processi biologici convenzionali, più economici, con i PAO, più costosi. È stato proposto un modello MINLP (Nonlinear Mixed Integer Programming) per l'ottimizzazione di una rete di acque reflue, basato su una struttura attraverso la quale è possibile rappresentare scelte progettuali alternative, che è stato implementato e risolto in GAMS. La nuova formulazione include il rapporto BOD5 / COD, che descrive l'efficienza di eliminazione di BOD5 e COD di un trattamento al fine di modellare la variazione della biodegradabilità degli influenti. Questa nuova formulazione consente di determinare le diverse possibilità di combinazione dei PAO con i trattamenti biologici e apre la strada a modelli più complessi volti a risolvere l'equilibrio tra costo ed efficienza del trattamento.Postprint (published version

Optimisation multicritère de réseaux d'eau

Cette étude concerne l’optimisation multiobjectif de réseaux d’eau industriels via des techniques de programmation mathématique. Dans ce travail, un large éventail de cas est traité afin de proposer des solutions aux problèmes de réseaux les plus variés. Ainsi, les réseaux d’eau monopolluants sont abordés grâce à une programmation mathématique linéaire (MILP). Cette méthode est ensuite utilisée dans le cadre d’une prise en compte simultanée des réseaux d’eau et de chaleur. Lorsque le réseau fait intervenir plusieurs polluants, le problème doit être programmé de façon non linéaire (MINLP). L’optimisation multicritère de chaque réseau est basée sur la stratégie epsilon-contrainte développée à partir d’une méthode lexicographique. L’optimisation multiobjectif suivie d’une réflexion d’aide à la décision a permis d’améliorer les résultats antérieurs proposés dans la littérature de 2 à 10% en termes de consommation de coût et de 7 à 15% en ce qui concerne la dépense énergétique. Cette méthodologie est étendue à l’optimisation de parcs éco-industriels et permet ainsi d’opter pour une solution écologique et économique parmi un ensemble de configurations proposées. ABSTRACT : This study presents a multiobjective optimization of industrial water networks through mathematical programming procedures. A large range of various examples are processed to propose several feasible solutions. An industrial network is composed of fixed numbers of process units and regenerations and contaminants. These units are characterized by a priori defined values: maximal inlet and outlet contaminant concentrations. The aim is both to determine which water flows circulate between units and to allocate them while several objectives are optimized. Fresh water flow-rate (F1), regenerated water flow-rate (F2),interconnexions number (F3), energy consumption (F4) and the number of heat exchangers (F5) are all minimized. This multiobjective optimization is based upon the epsilon-constraint strategy, which is developed from a lexicographic method that leads to Pareto fronts. Monocontaminant networks are addressed with a mixed linear mathematical programming (Mixed Integer Linear Programming, MILP) model, using an original formulation based on partial water flow-rates. The obtained results we obtained are in good agreement with the literature data and lead to the validation of the method. The set of potential network solutions is provided in the form of a Pareto front. An innovative strategy based on the GEC (global equivalent cost) leads to the choice of one network among these solutions and turns out to be more efficient for choosing a good network according to a practical point of view. If the industrial network deals with several contaminants, the formulation changes from MILP into MINLP (Mixed Integer Non Linear Programming). Thanks to the same strategy used for the monocontaminant problem, the networks obtained are topologically simpler than literature data and have the advantage of not involving very low flow-rates. A MILP model is performed in order to optimize heat and water networks. Among several examples, a real case of a paper mill plant is studied. This work leads to a significant improvement of previous solutions between 2 to 10% and 7 to 15% for cost and energy consumptions respectively. The methodology is then extended to the optimization of eco-industrial parks. Several configurations are studied regarding the place of regeneration units in the symbiosis. The best network is obtained when the regeneration is owned by each industry of the park and allows again of about 13% for each company. Finally, when heat is combined to water in the network of the ecopark, a gain of 11% is obtained compared to the case where the companies are considered individually

Bilevel optimization of Eco-Industrial parks for the design of sustainable resource networks

This work presents a bilevel programming framework for the design of sustainable resource networks in eco-industrial parks (EIP). First, multiobjective optimization methods are explored in order to manage the multi-criteria nature of EIP network design problems. Then, different case studies are modeled in order to minimize and maintain in equilibrium participating plants operating costs while minimizing resource consumption. Thus, the structure of the model is constituted by a bilevel programming framework where the enterprises’ plants play a Nash game between them while being in a Stackelberg game structure with the authority. This structure defines a model which, in order to be solved, has to be transformed into a MOPEC (Multiple Optimization Problems with Equilibrium Constraints) structure. Regarding the case studies, monocontaminant water networks in EIP are studied first, where the influence of plants operating parameters are studied in order to determine the most important ones to favor the symbiosis between plants. The water network is composed of a fixed number of process and water regeneration units where the maximal inlet and outlet contaminant concentrations are defined a priori. The aim is to determine which processes are interconnected and the water regeneration allocation. Obtained results highlight the benefits of the proposed model structure in comparison with traditional multiobjective approaches, by obtaining equilibrate different plants operating costs (i.e. gains between 12-25%) while maintaining an overall low resource consumption. Then, other case studies are approached by using the bilevel structure to include simultaneously energy networks in a multi-leader-multi-follower formulation where both environmental authorities are assumed to play a noncooperative Nash game. In the first case study, economic gain is proven to be more significant by including energy networks in the EIP structure. The second industrial case study explores a supply-demand utility network model where the environmental authority aims to minimize the total equivalent CO2 emissions in the EIP. In all cases, the enterprises’ plants are encouraged to participate in the EIP by the extremely favorable obtained results