Doctor of Philosophy / Department of Agronomy / Ignacio Ciampitti / Potential yield (PY) is defined by the yield limited by temperature, radiation, and genetics – under no limitation on nutrients or water. The difference between PY and actual yield (AY) is defined as yield gap (YG). Management practices such as planting date, row spacing, seeding rate, fertilization program, pest, and disease control can help producers to intensify the productivity of the farming systems and consequently, close the YGs. To evaluate the impact of different management system (MS, specific combination of management practices) on closing the YG the following objectives were established: i) conduct a historical synthesis analysis to characterize shifts in soybean yields, biomass and nutrient uptake and partitioning dissecting the main physiological component related to nutrient use efficiency, seed nutrient composition and nutrient stoichiometry; ii) study the contribution of five MS for intensifying maize-soybean production systems; iii) quantify the nitrogen (N) contribution from the biological N fixation (BNF) process for soybeans under two contrasting MSs (low vs. high inputs); and iv) utilize the same contrasting input treatments to calibrate the Agricultural Production System Simulator (APSIM) for modeling a maize – soybean rotation and apply the parametrized model to estimate a long-term (1980-2016) simulation. For the first objective, main findings indicate that soybean yield increase over time was driven by an increase in biomass with a relatively small variation in harvest index, and with modern varieties producing more yield per unit of N uptake. For the second objective, field experiments demonstrated that intensification practices (narrow row spacing, increasing seeding rate and implementation of a balanced nutrition program) increased yields in both soybeans and maize under rainfed and irrigated conditions. For the third objective, to better understand the soybean N status, BNF measurements were collected during the 2015 growing season and also investigated in a greenhouse setting. The B value, N fixation when plants are fully relying on atmospheric N, changed among varieties, growth stages and plant fractions. Overall B value at R7 (beginning of maturity) was -1.97 contrasting with the -1.70 value reported as mode according to a literature review. For the range of fixation measured in this research (average of 45-57%), utilization of a B value obtained from the scientific literature or measured in field conditions will have a reduced impact on BNF estimations. Lastly, for the last and fourth objective, the APSIM performed well in estimating yield, biomass production and total N uptake with a high model efficiency and low relative root mean square error (RRMSE). The long-term simulation helped characterize the YG for each crop and MS according to different weather patterns. The modeling approach increased the value of data collected in field experiments. Overall, this research project provided an approach to quantifying and understanding YGs in a maize-soybean rotation and the impact of different MSs on intensifying productivity. Future work can be conducted to model specific MSs to advise producers on the best management systems (BMSs) for sustainably intensifying productivity while minimizing the environmental footprint of current farming systems.

Orientador: Edson Rosa Francisco de Souza / Resumo: A intensificação é um processo rotineiro na vida de todos nós falantes de uma língua, uma vez que é a partir dela que tentamos convencer, reforçar, persuadir, isto é, mudar a informação pragmática do nosso interlocutor acerca daquilo que temos em mente e do que estamos vivenciando. Como afirma Costa (2010, p. 62), as experiências e as ações que o indivíduo vivencia em seu cotidiano não são sempre iguais, elas se diferenciam por diversos motivos, e um deles é a intensidade com que ocorrem, podendo variar entre maior ou menor força. Logo, as microconstruções intensificadoras do português, do tipo morto de fome, podre de rico, cansado pra caramba, entre outras, são utilizadas na língua com a função de exprimir uma noção superelevada acerca de algo, que ultrapassa os limites do que é concebido como relativamente normal pelo falante. Assim, tais construções intensificadoras funcionam como estratégias discursivas que lançam mão do recurso da metaforização, isto é, não carregam consigo somente o sentido literal, mas também outros significados (construídos via metáfora ou metonímia). Apresentam um pareamento direto de forma-sentido (CROFT, 2001; GOLDBERG, 2006), com uma estrutura sequencial, que inclui tanto posições fixas quanto posições abertas e apresentam diferentes graus de esquematicidade, composicionalidade e analisabilidade. Sendo assim, com base nos pressupostos teóricos da abordagem construcional (TRAUGOTT e TROUSDALE, 2013; BYBEE, 2010), o objetivo deste trabalho é analisa... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Intensification is a routine process in all of our lives' who speaks a language, since it is from there we try to convince, reinforce, persuade, it means, change the pragmatic information of our interlocutor about what we have in mind and what we are experiencing. As Costa (2010, p. 62) states, the experiences and actions that individuals experience in their daily lives are not always the same, they differ for different reasons and one of them is the intensity with which they occur, which may vary between greater or lesser strength. Therefore, the peripheral intensifying microconstructions of Brazilian Portuguese, of the type “morto de fome”, “podre de rico”, “cansado pra caramba”, among others, are used in the language with the function of expressing a superelevated notion about something, which goes beyond the limits of what is conceived to be relatively normal by the speaker. thus, such intensifying constructions function as discursive strategies that use the resource of metaphorization, wich means, they carry not only the literal meaning, but also other meanings (constructed via metaphor or metonymy). They present a direct pairing in a meaningful way (CROFT, 2001; Goldberg, 2006), with a sequential structure, which includes both fixed and open positions and show different degrees of schematicity, compositionality and analyzability. Therefore, based on the theoretical assumptions of the constructional approach (Traugott and Trousdale, 2013; Bybee 2010), this study's object... (Complete abstract click electronic access below) / Mestre

Drought is conventionally known as a slow-developing natural hazard. In recent years, a subset of drought events characterized by rapid onset has been identified and deemed “flash” droughts. These flash droughts can result in rapid soil drying and rapid vegetation degradation making them damaging to agriculture and the economy, so it is essential to develop reliable early warning systems for flash drought events. This study aims to compare the climatology between flash and non-flash droughts across the Contiguous United States (CONUS) and regionally to identify key differences in the drought types to improve early warning. Flash drought is defined as a two- or more category degradation in the U.S. Drought Monitor (USDM) in 4 weeks or less. Potential evapotranspiration (PET), vapor pressure deficit (VPD), maximum temperature (Tmax), and minimum temperature (Tmin) from the Gridded Surface Meteorological Dataset (gridMET) were also analyzed for flash and non-flash drought. It was found that using this definition of flash drought, flash droughts are up to 70% more likely to occur than non-flash droughts over all of the CONUS except the west coast. The South and Southwest regions are more likely to have more frequent and longer flash drought events than the Northwest and Plains regions. This study concludes that PET and VPD are the most reliable variables for differentiating between a flash and non-flash drought event. Furthermore, flash drought is most prevalent and will be the most difficult to predict in the South and Southwest regions and easier to predict in the Northwest and Plains. Also, using a flash drought definition of a drop in two or more categories in the USDM may be too lenient. A narrower flash drought definition, such as a drop in two categories over a two- or three-week period, may be more reflective of the more damaging nature of flash drought events.

Spherical agglomeration (SA) is a novel process intensification strategy for particulate manufacturing. In the context of pharmaceutical manufacturing, it has the potential to reduce the number of unit operations in downstream processing from seven to three, which significantly reduces the manufacturing cost. However, SA process development for a new API in the drug pipeline is still a challenging exercise, which has impeded its practical implementation. The major bottleneck lies in the lack of fundamental understanding of the mechanistic principles underlying agglomeration of primary crystals, which can enable rational process design. In addition, most SA processes reported in literature focus on only the API, which does not eliminate the blending and wet granulation unit operations. The major purposes of this thesis are to (i) develop a first principle mathematical framework which can identify the fundamental agglomeration mechanism (ii) develop a model based online optimization framework, which can control the process, even in the presence of model parametric uncertainties (iii) develop a rational framework for co-agglomerating APIs and excipients, guided by process analytical technology tools. It is believed that the novel technology developed in this thesis will lay the groundwork for fast and robust process development of co-agglomerating APIs and excipients in the future, thereby enabling one-step direct compression. The large-scale development and deployment of this technology will significantly reduce the time to market and the manufacturing costs for new APIs, thereby ensuring higher accessibility of life-saving drugs.

An analysis to determine physical and spatial patterns of the surface latent heat flux (LHF) and near surface (5m) salinity (NSS) beneath tropical cyclones (TCs) in the North Atlantic and eastern North Pacific basins during the first 24 hours of rapid intensification (RI) was conducted using empirical orthogonal function (EOF) analysis. To determine if these patterns were unique to RI, TC RI cases were compared to three non-RI intensification thresholds, 10 kt, 15 kt and 20 kt, for both LHF and NSS. Though similarities exist between non-RI and RI cases physical and spatial patterns unique to the RI cases did exist. Sea surface temperatures associated with statistically identified TC groups were assessed for their potential influence on RI. While inconclusive in the eastern North Pacific, NSS in the Atlantic may play a role for RI TCs in areas affected by river discharge from South America.

While the quest of the human civilization continues towards a more sustainable energy resource, current energy conversion technologies need to be improved such that the rate of environmental impact that has occurred due to the rapid industrialization since the 20th century is mitigated. This search has motivated research into new energy conversion technologies that aim to reduce the environmental impact by either improving the efficiencies of existing technologies, developing new technologies with zero emissions or by improving reliability and reducing the cost of renewable energy. Process intensification through process integration is one of the areas of active research that improves the system efficiency by exploiting the synergies that exist between different processes. This thesis considers the design and operational feasibility of heat integrating two conventional industrial processes – gasification and steam reforming of methane for application in polygeneration. To this end, complex mathematical models that describe the integrated system are developed to study different design prospects and to determine if the device can be safely operated in a plant producing electricity, liquid fuels and hydrogen. The designs proposed in this thesis show that significant methane conversion comparable to industrial reformers can be achieved while providing the required cooling duty to the gasifier. The proposed integrated system produces hydrogen rich reformer synthesis gas (hydrogen and carbon monoxide) that can be blended with the hydrogen lean coal synthesis gas providing flexibility to change the molar H2/CO ratio necessary for different downstream processes in a polygeneration plant. Moreover, the results show that the integration helps improve plant carbon efficiency and reduce CO2 emissions. The major contribution of this thesis is the development of designs based on representative mathematical models that are safe to operate for producing several chemicals in polygeneration plants. / Dissertation / Doctor of Philosophy (PhD)

Forecasting rapid intensification (RI) of tropical cyclones (TCs) is considered one of the most challenging problems for the TC operational and research communities and remains a top priority for the National Hurricane Center. Upon landfall, these systems can have detrimental impacts to life and property. To support continued improvement of TC RI forecasts, this study investigated large-scale TC environments undergoing RI in the North Atlantic basin, specifically identifying important diagnostic variables in three-dimensional space. These results were subsequently used in the development of prognostic machine learning algorithms designed to predict RI 24 hours prior to occurrence. Using three RI definitions, this study evaluated base-state and derived meteorological parameters through S-mode and T-mode rotated principal component analysis, hierarchical compositing analysis, and hypothesis testing. Additionally, nine blended intelligence ensembles were developed using three RI definitions trained on data from the Statistical Hurricane Intensity Prediction Scheme- Rapid Intensification Index, Global Ensemble Forecast System Reforecast, and Final Operational Global Analysis. Performance metrics for the intelligence ensembles were compared against traditional linear methods. Additionally, a tenth ensemble was created using forecast data generated from Weather Research and Forecasting model simulations of TC RI events in the open North Atlantic and compared against linear methods. Results revealed modest classification ability of machine learning algorithms in predicting the onset of RI 24 hours in advance by including TC environmental spatial information of temperature and moisture variables, as well as variables indicative of ambient environmental interactions.

Anaerobic digestion (AD) is an essential process in wastewater treatment to stabilize waste organic solids and produce biogas. This research is comprised of two projects in the discipline of anaerobic digestion. First, the effect of high sulfate concentration on anaerobic digestion of wastewater sludge was investigated. Secondly, the performance of acetoclastic methanogens Methanosaeta spp. and Methanosarcina spp. were investigated under intensified AD operation conditions (i.e., elevated acetate concentrations, vigorous mixing, etc.). In the sulfate experiments, the cumulative biogas and methane production decreased linearly with increasing initial sulfate doses (0 – 3,300 mg S L-1) and the correlation between the sulfate dose and methane production was verified with theoretical predictions, indicating complete reduction of sulfate to sulfide in AD. The examined sulfate concentrations resulted in no clear negative effects on the COD (chemical oxygen demand) removal or VSS (volatile suspended solids) destruction of the wastewater sludge, indicating that previous findings on sulfide toxicity might have been attributed to potential COD overestimation of digested sludge with high levels of sulfide. To avoid potential misinterpretation of AD performance on sulfide toxicity effects, we proposed a new method for COD correction for digested sludge. In the second project focused on acetoclastic methanogens, vigorous mixing conditions substantially decreased Methanosarcina spp. growth and methane production, and the decreased methanogenesis was more pronounced at higher acetate concentrations. Methanosarcina spp. prefer to grow in clusters and the vigorous mixing can disrupt cluster formation; as a result, reduced chances for cluster formation limited the growth of Methanosarcina spp.. While Methanosarcina spp. growth and methane production increased with the increasing acetate concentration, Methanosaeta spp. growth was unaffected by the examined vigorous mixing and soluble substrate conditions with negligible relative growth. Thus, rapid enrichment of Methanosarcina spp. is critical for successful operation intensified of AD processes under high organic loading conditions. / Thesis / Master of Applied Science (MASc)

[ES] El actual enfoque hacia la desfosilización de la industria química acentúa la necesidad de desarrollar procesos químicos medioambientalmente más sostenibles. El diseño de sistemas catalíticos en tándem para llevar a cabo reacciones mecanísticamente desacopladas en un solo reactor, representa una estrategia prometedora para potencialmente reducir el tamaño de las instalaciones y alcanzar mayores eficiencias energéticas y económicas. El gas de síntesis y sus derivados directos C1 (metanol, DME) representan una atractiva fuente de carbono no derivada del petróleo para la producción de productos químicos. La propagación selectiva de cadena desde compuestos C1 hasta específicamente productos sigue siendo un desafío importante en el campo de la catálisis heterogénea. En esta tesis, se presenta cómo el diseño racional de un sistema catalítico en tándem, multifuncional y heterogéneo, proporciona una ruta novedosa y alternativa para la síntesis directa de productos C3 de interés a partir de compuestos C1. En este trabajo, se ha estudiado la integración en tándem de la reacción de carbonilación de compuestos metoxi (DME) con CO, con la posterior cetonización de los productos carboxílicos C2 intermedios correspondientes en un sistema catalítico multifuncional. La integración de los catalizadores Ag/MOR y Pd/ZrCeOx respectivamente, permite la síntesis directa de acetona a partir de mezclas de DME/gas de síntesis a 548 K y 20 bares. La incorporación de H-FER nanocristalina en un catalizador multifuncional metal/óxido/zeolita Pd/ZrCeOx:FER, como funcionalidad específica de hidrólisis del acetato de metilo, ha permitido la obtención de rendimientos a acetona hasta tres veces mayores en comparación con los obtenidos utilizando solamente el catalizador metal/óxido. La funcionalidad específica de hidrólisis se ha incorporado en base a los resultados de estudios cinéticos realizados para las etapas de reacción por separado, que revelan una limitación general de la velocidad de cetonización a partir del paso de hidrólisis ácida del intermedio acetato de metilo. A una distancia intercatalítica en el rango de micrómetros, se ha mantenido una conversión de DME estable (superior al 94%), junto con una selectividad de acetona del 65-70% (entre los productos orgánicos) durante al menos 10 días de operación continua. Además, la atmósfera de gas de síntesis a alta presión permite la integración de la hidrogenación de grupos carbonilo, abriendo la puerta para la producción de 2-propanol en un solo reactor. En particular, la incorporación del catalizador de hidrogenación Ag-Pt/¿-Al2O3 ha permitido alcanzar una selectividad de 2-propanol del 51% dentro de la fracción de productos C3. Finalmente, el concepto de conversión en tándem mencionado anteriormente se ha extendido a la conversión directa de mezclas de DME/gas de síntesis a propileno. Con este fin, se han desarrollado catalizadores basados en Ag/SiO2 como una funcionalidad de hidrodeshidratación de acetona y se han acoplado al sistema catalítico multifuncional en tándem desarrollado para la producción de acetona. A una temperatura de reacción en el rango de 548-578 K y una presión total de 15 bares, el sistema catalítico en tándem proporciona ratios propileno-a-etileno en el rango 6-9, y selectividades de propileno de hasta el 40%, para una conversión de DME >97%, demostrando que esta ruta de producción es intrínsecamente más selectiva hacia propileno que la mayoría de los procesos de metanol-a-propileno reportados. Además, la temperatura de reacción relativamente suave y el carácter reductor de la atmósfera de gas de síntesis inhiben la deposición de coque, proporcionando un comportamiento estable durante períodos de operación superiores a 214 horas. Aunque se requiere mayor optimización en cuanto al rendimiento a propileno, los resultados abren la puerta a un nuevo proceso para la producción de propileno a partir de materias primas C1, alternativo a los procesos de metanol-a-hidrocarburos. / [CA] L'actual enfocament cap a la desfossilització de la indústria química accentua la necessitat de desenvolupar processos químics mediambientalment més sostenibles. En aquest context, el disseny de sistemes catalítics en tàndem per a dur a terme reaccions mecanísticamente desacoblades en un sol reactor, representa una estratègia prometedora per potencialment reduir la grandària de les instal·lacions i aconseguir majors eficiències energètiques i econòmiques. El gas de síntesi i els seus derivats directes C1 (metanol, DME) representen una atractiva font de carboni no derivada del petroli. La propagació selectiva de cadena des de compostos C1 fins específicament productes C3 continua sent un desafiament important en el camp de la catàlisi heterogènia. En aquesta tesi, es presenta com el disseny racional d'un sistema catalític en tàndem, multifuncional i heterogeni, proporciona una ruta nova i alternativa per a la síntesi directa de productes C3 d'interés a partir de compostos C1. En aquest treball, s'ha estudiat la integració en tàndem de la reacció de carbonilació de compostos metoxi (DME) amb CO, amb la posterior cetonització dels productes carboxílics C2 intermedis corresponents en un sistema catalític multifuncional. La integració dels catalitzadors Ag/MOR i Pd/ZrCeOx respectivament, permet la síntesi directa d'acetona a partir de mescles de DME/gas de síntesi a 548 K i 20 bars. La incorporació d'H-FER nanocristalina en un catalitzador multifuncional metall/òxid/zeolita Pd/ZrCeOx:FER, com a funcionalitat específica d'hidròlisi de l'acetat de metil, intermedi en el procés global, ha permés l'obtenció de rendiments a acetona fins a tres vegades majors en comparació amb els obtinguts utilitzant solament el catalitzador metall/òxid, Pd/ZrCeOx. La funcionalitat específica d'hidròlisi s'ha incorporat sobre la base dels resultats d'estudis cinètics realitzats per a les etapes de reacció per separat, que revelen una limitació general de la velocitat de cetonització a partir del pas d'hidròlisi àcida de l'intermediari acetat de metil. A una distància intercatalítica en el rang de micròmetres, s'ha mantingut una conversió de DME estable (superior al 94%), juntament amb una selectivitat d'acetona del 65-70% (entre tots els productes orgànics) durant almenys 10 dies d'operació contínua. A més, l'atmosfera de gas de síntesi a alta pressió permet la integració de la hidrogenació de grups carbonil, obrint la porta per a la producció no sols d'acetona, sinó també de 2-propanol en un sol reactor. En particular, la incorporació del catalitzador d'hidrogenació Ag-Pt/¿-Al2O3 ha permés aconseguir una selectivitat de 2-propanol del 51% dins de la fracció de productes C3 (és a dir, acetona, 2-propanol, propà i propilé). Finalment, el concepte de conversió en tàndem esmentat anteriorment s'ha estés a la conversió directa de mescles de DME/gas de síntesi a propilé. A aquest efecte, s'han desenvolupat catalitzadors basats en Ag/SiO2 com una funcionalitat de hidro-deshidratació d'acetona i s'han acoblat al sistema catalític multifuncional en tàndem desenvolupat per a la producció d'acetona. A una temperatura de reacció en el rang de 548-578 K i una pressió total de 15 bars, el sistema catalític multifuncional en tàndem proporciona ràtios propilé-a-etilé en el rang 6-9, i selectivitats de propilé de fins al 40%, per a una conversió de DME >97%, demostrant que aquesta ruta de producció és intrínsecament més selectiva cap a propilé que la majoria dels processos de metanol-a-propilé reportats. A més, la temperatura de reacció relativament suau i el caràcter reductor de l'atmosfera de gas de síntesi inhibixen la deposició de coc, proporcionant un comportament estable durant períodes d'operació superiors a 214 hores. Encara que es requereix una major optimització quant al rendiment a propilé, els resultats obrin la porta a un nou procés per a la producció de propilé a partir de matèries primeres C1, alternatiu als processos de metanol-a-hidrocarburs. / [EN] The present focus on advancing towards a defossilized chemical industry underscores the need for developing more environmentally sustainable chemical processes. In this context, the design of tandem-catalytic systems to steer mechanistically decoupled reactions in a cascade fashion, in a single reactor, represents a promising strategy for potentially reduce the installed size of chemical processes and attain higher energy- and cost-efficiencies. Synthesis gas and its direct C1 derivatives (methanol, DME), represent an attractive non-petroleum derived carbon source for the production of commodity chemicals. The selective chain propagation from C1 building blocks to specifically C3 compounds has been demonstrated through biocatalytic routes, however it remains an important challenge for heterogeneous catalysis. In this thesis, we report how the design and engineering of a multifunctional, heterogeneous tandem-catalytic system provides a novel and alternative route for the direct synthesis of C3 compounds from C1 building blocks. The selective obtention of C2+ products with specific chain lengths, surpassing the inherently non-selective C-C chain propagation characteristic of Fischer-Tropsch polymerization reactions, poses a significant challenge. In this work, the tandem integration of the reaction of carbonylation of methoxy compounds (DME) with CO, with subsequent ketonisation of the corresponding C2 carboxylic intermediate products on a multifunctional catalytic system is reported. The integration of an optimized Ag/MOR and Pd/ZrCeOx catalysts, respectively, allows the direct synthesis of acetone from DME/syngas mixtures at 548 K and 20 bar. Enhanced acetone time-yields, i.e. by a factor greater than three, have been obtained by incorporation of nanosized H-FER, as a specific ester hydrolysis functionality in a Pd/ZrCeOx:FER metal/oxide/zeolite multifunctional ketonisation composite catalyst. The specific hydrolysis functionality was implemented based on insights from kinetic studies on the individual reaction steps revealing overall ketonisation rate limitation from the methyl acetate intermediate acid-catalysed hydrolysis step. At the micro-meter range carbonylation/ketonisation intercatalysts spacing, a noticeably stable DME conversion (of >94%), alongside ca. 65-70% acetone selectivity (within all organic products) has been sustained for at least 10 days on-stream. Furthermore, the high-pressure syngas atmosphere allows integrating the hydrogenation of carbonyl groups therefore opening the door for the production of not only acetone but also 2-propanol in a single reactor. Particularly, Ag-Pt/¿-Al2O3 hydrogenation catalyst afforded reaching a 2-propanol selectivity of 51% within the C3 products fraction (i.e. acetone, 2-propanol, propane and propylene). Finally, the above tandem conversion concept has been extended to the direct conversion of DME/syngas mixtures to propylene. To this end, Ag/SiO2 catalysts have been developed as an acetone hydrodehydration functionality and coupled to the multifunctional catalytic-tandem system developed for acetone production from DME/syngas mixtures. At a reaction temperature in the range of 548-578 K and a total pressure of 15 bar, the multifunctional catalytic system affords a remarkably high propylene-to-ethylene molar ratio of 6-9 and overall propylene selectivities up to 40%, at essentially full DME conversion (>97%), proving this production route intrinsically more selective to propylene than most of methanol-to-propylene processes. Moreover, the comparatively mild reaction temperature and the reducing character of the syngas atmosphere inhibit coke deposition, leading to stable performance for times-on-stream in excess of 214 hours. While future improvements in propylene time-yield will be required, the results open the door to a new process for propylene production from C1 feedstocks, alternative to methanol-to-hydrocarbons processes. / I would like to thank the Spanish Ministry of Science, Innovation and Universities (MCIU) for my FPU fellowship (FPU17/04751) and the European Research Council (ERC) under the Horizon 2020 research and innovation program (ERC-CoG- TANDEng; grant agreement 864195), which have made possible the realization of this thesis. BASF SE (Ludwigshafen, Germany) is gratefully acknowledged for their support to fundamental research efforts in catalysis, a portion of which has contributed to the outcomes presented in this PhD thesis. I would also like to thank the Spanish Research Council (CSIC) and, particularly, the Institute of Chemical Technology (ITQ), for providing the infrastructure where I have developed my PhD work. Next, I want to thank the Massachusetts Institute of Technology (MIT) for giving me access to their facilities during my short PhD research stay, and to the ALBA synchrotron, especially to the CLÆSS beamline, for the several beamtimes granted. Finally, I would like to thank the department of Chemical and Nuclear Engineering (DIQN) of the Polytechnic University of Valencia (UPV), for hosting me as a teaching assistant over these years / Andrés Marcos, E. (2024). Tandem Catalysis for Selective C1-to-C3 Chain Propagations towards Platform Chemicals Production [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/204891

Il est démontré que dans de nombreux procédés de transformation de la matière, les dégradations entropiques (et les consommations énergétiques qui en découlent) peuvent être minimisées en répartissant les flux d’énergies dans le volume plutôt qu’aux bornes du système (exemple de la distillation diabatique). Cependant la réalisation et la gestion de profils thermiques contrôlés (tels que des gradients thermiques et des étagements de température maîtrisés) dans les appareils compactes ne sont pas très souvent réalisées parce que souvent complexes et coûteuses (batterie d’échangeurs, gestion des fluides). Cette difficulté technologique affecte non seulement les performances énergétiques et les efficacités de transformation des appareils classiques de grandes tailles, mais aussi les réacteurs microstructurés dont les faibles dimensions internes associées à la grande conductivité thermique du matériau constituant les parois du contacteur entraînent souvent l’homogénéité thermique de l’appareil au détriment de la gestion des gradients thermiques. Par ailleurs, les garnissages utilisés dans les séparateurs sont de formes très complexes dans lesquels il est difficile de faire à la fois de la structuration thermique et hydrodynamique. Les systèmes microstructurés basés sur des géométries à plaques semblent offrir une possibilité intéressante de structuration thermique (contrôle et modulation de flux énergétiques pour l’obtention d’un profil thermique spécifique) et hydrodynamique (contrôle des transferts de matière, des temps de séjour, des pertes de charges etc.). Dans cette thèse, les réflexions menées sur ces verrous technologiques ont conduit à la conception d’un microcontacteur à film tombant. Ce microprocédé a été caractérisé d’un point de vue thermique et hydrodynamique. Une étude de faisabilité sur le potentiel de ce microcontacteur à séparer un mélange binaire d’alcools (ethanol/n-propanol) a été menée, ses performances ont été expérimentalement évaluées d’un point de vue qualitatif (pureté du distillat et du soutirat) et quantitatif (rapports des débits entrant et sortant), mais aussi en intégrant la notion d’exergie compositionnelle, également appelée puissance de séparation / In many processes of mass transformation, entropic degradations (and energy consumptions which results from) can be minimized by distributing heat flows in all process volume rather than boundaries (example: diabatic distillation). However it is difficult to control and impose thermal gradients on small scales because of their complexity and high costs (exchangers, fluids). This technological difficulty affects not only the performances and energy efficiencies of conventional devices (macro scales) but also small devices (e.g. microstructured reactors). Indeed, compact equipments with small dimensions generate some difficulties. First, the driving force inducing liquid flow by gravity is very small. Second, small size and high thermal conductivity of the material induce thermal homogeneity instead of managing temperature gradients in the system. In many separators, the used packing material has complex forms that make difficult thermal and hydrodynamic structurations. Microstructured devices, based on microchannel plate technologies, offer an interesting possibility of thermal structuration (control and modulation of energy fluxes) and hydrodynamics control (e.g. mass transfer, residence times, pressure drop etc). In this thesis, many discussions on these technological barriers led to the design of a new microstructured falling film contactor. The aim of the present work is to study heat transfer phenomena and liquid hydrodynamics in this device and, investigates the separation feasibility of a binary mixture of ethanol and n-propanol. Microcontactor performances were experimentally evaluated in terms of quality (bottom and top concentrations) and quantity (bottom and top flow rate ratios). To fully characterize contactor performances, the separation power concept (also called compositional exergy) was integrated