Process intensification education contributes to sustainable development goals: Part 2

Achieving the United Nations sustainable development goals requires industry and society to develop tools and processes that work at all scales, enabling goods delivery, services, and technology to large conglomerates and remote regions. Process Intensification (PI) is a technological advance that promises to deliver means to reach these goals, but higher education has yet to totally embrace the program. Here, we present practical examples on how to better teach the principles of PI in the context of the Bloom's taxonomy and summarise the current industrial use and the future demands for PI, as a continuation of the topics discussed in Part 1. In the appendices, we provide details on the existing PI courses around the world, as well as teaching activities that are showcased during these courses to aid students’ lifelong learning. The increasing number of successful commercial cases of PI highlight the importance of PI education for both students in academia and industrial staff.We acknowledge the sponsors of the Lorentz’ workshop on“Educating in PI”: The MESA+Institute of the University of Twente,Sonics and Materials (USA) and the PIN-NL Dutch Process Intensi-fication Network. DFR acknowledges support by The Netherlands Centre for Mul-tiscale Catalytic Energy Conversion (MCEC), an NWO Gravitationprogramme funded by the Ministry of Education, Culture and Sci-ence of the government of The Netherlands. NA acknowledges the Deutsche Forschungsgemeinschaft (DFG)- TRR 63¨Integrierte Chemische Prozesse in flüssigen Mehrphasen-systemen¨(Teilprojekt A10) - 56091768. The participation by Robert Weber in the workshop and thisreport was supported by Laboratory Directed Research and Devel-opment funding at Pacific Northwest National Laboratory (PNNL).PNNL is a multiprogram national laboratory operated for theUS Department of Energy by Battelle under contract DE-AC05-76RL0183

Process intensification education contributes to sustainable development goals : part 1

In 2015 all the United Nations (UN) member states adopted 17 sustainable development goals (UN-SDG) as part of the 2030 Agenda, which is a 15-year plan to meet ambitious targets to eradicate poverty, protect the environment, and improve the quality of life around the world. Although the global community has progressed, the pace of implementation must accelerate to reach the UN-SDG time-line. For this to happen, professionals, institutions, companies, governments and the general public must become cognizant of the challenges that our world faces and the potential technological solutions at hand, including those provided by chemical engineering. Process intensification (PI) is a recent engineering approach with demonstrated potential to significantly improve process efficiency and safety while reducing cost. It offers opportunities for attaining the UN-SDG goals in a cost-effective and timely manner. However, the pedagogical tools to educate undergraduate, graduate students, and professionals active in the field of PI lack clarity and focus. This paper sets out the state-of-the-art, main discussion points and guidelines for enhanced PI teaching, deliberated by experts in PI with either an academic or industrial background, as well as representatives from government and specialists in pedagogy gathered at the Lorentz Center (Leiden, The Netherlands) in June 2019 with the aim of uniting the efforts on education in PI and produce guidelines. In this Part 1, we discuss the societal and industrial needs for an educational strategy in the framework of PI. The terminology and background information on PI, related to educational implementation in industry and academia, are provided as a preamble to Part 2, which presents practical examples that will help educating on Process Intensification

Réacteurs microstructurés : hydrodynamique, thermique, transfert de matière et applications aux procédés

The present manuscript presents an analysis of flow and transport phenomena in microstructure reactors, their influence on the behavior of the reactors and the major interest and areas of application for the use of microtechnology in ptocess engineering. Hydrodynamic conditions and space-times in the numerous channèls are accurately controlled by appropriate design of the reactor. The residence time distribution, although narrow in a single microchannel, is significantly dispersed in the reactor due to flow singularities. Nevertheless, microstructured reactors are suited to periodic operation at frequencies higher than 1 Hz. The thermal behavior, characterized by significant axial conduction, leads to spatial isothermicity in metallic reactors and requires the use of poody conducting ni'aterials to maintain temperature gradients. Under transient conditions, following a step change in fluid temperatures; the reactor temperature variation can be represented by two characteristic times, one internal, the other external. In mass transfer, an axial diffusion effect can predominate with respect to convection, which increases the Sherwood number and back-mixing. Nevertheless, the determination of kinetic parameters being accurate for the low Damkohler numbers attainable, microchannelreactors provide favorable conditions for the study of rapid, reactions. A synthesis of the above-mentioned points indicates several advantages for microstructured reactors, such as a significant energy saving induced by the structuring of the,flow in' parallel channels. Intensification of heat exchange in microchanne1 dimensions limits therisks of thermal runaway by removing heat generatedhy exothermic reactions and allows miniaturization of production units without loss in productivity. Finally, lleat and mass transfer by conduction and diffusion are favored with respect to reacticin and hence microstructured reactors are well suited to kinetic measurement and to development of new processes limited by heat and mass transfer.Ce mémoire présente une analyse de l'écoulement et des phénomènes de transfert dans les réacteurs microstructurés, leur influence sur le comportement des réacteurs et les principaux intérêts et domaines d'utilisation des microtechniques en Génie des Procédés. L'hydrodynamique et les temps de passage dans les nombreux canaux parallèles sont finement maîtrisés par un dimensionnement approprié du réacteur. La distribution des temps de séjour, bien que peu étalée dans un microcanal unique, est très dispersée dans le réacteur à cause des singularités de l'écoulement. Néanmoins, ces réacteurs sont adaptés pour la conduite périodique à des fréquences supérieures au Hertz. Le comportement thermique, caractérisé par un effet axial de conduction, induit l'isothermicité des réacteurs métalliques et requiert l'emploi de matériaux peu conducteurs pour maintenir un gradient de température. En régime transitoire, suite à un échelon de température des fluides, la température du réacteur est caractérisée par des temps internes et externes. En transfert de matière, un effet de diffusion axiale dans les microcanaux peut prédominer par rapport à la convection, ce qui augmente le nombre de Sherwood et le rétromélange. Néanmoins, la détermination de paramètres cinétiques étant précise dès que le nombre de Damkohler est faible, ces réacteurs fournissent des conditions favorables pour l'étude de réactions rapides. La synthèse de ces points montre plusieurs avantages des réacteurs microstructurés tels qu'un gain énergétique significatif induit par la structuration de l'écoulement en canaux parallèles. L'intensification des échanges dans ces dimensions limite les risques d'emballement en évacuant la chaleur des réactions exothermiques et permet de miniaturiser une installation à productivité constante. Enfin, les transferts par conduction et diffusion sont favorisés par rapport aux réactions si bien que ces réacteurs sont adaptés aux études cinétiques et au développement de nouveaux procédés limités par ces transferts

From Process Miniaturization to Structured Multiscale Design: The Innovative, High-Performance Chemical Reactors of Tomorrow

The increasing use in recent years of microstructured components and devices for chemical analysis and laboratory applications has led to the development of a large number of miniaturized reactor systems of proven performance and interest for the chemical industries. The primary objective of these small-scale devices has been to generate chemical information, and for such applications 'smaller' is very often 'better' since smaller devices allow for use of smaller reactant volumes. Contrary to chemical information, however, chemical production (even for mini-plants) implies the use of significant volumes of reactants, and the motivations for employing microstructured systems in such cases require therefore closer examination. Upon reflection, one concludes that the potential advantages of microstructured devices and components are not limited solely to process miniaturization. On the contrary, incorporation of appropriately designed and targeted microstructured components within large-scale macrodevices can provide novel, innovative design concepts for performance enhancement, resulting in safer, cleaner and more efficient reactors and process units for production plants of all sizes

Réacteurs microstructurés (hydrodynamique, thermique, transfert de matière et applications aux procédés)

NANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

Conception et dimensionnement de réacteurs-échangeurs microstructurés pour la production de gaz de synthèse par vaporeformage du méthane

L'efficacité globale du procédé de vaporeformage du gaz naturel est affectée par la limitation au transfert thermique au sein du lit catalytique et la génération d'un excès de vapeur d'eau non valorisable. Une des clés possibles pour le rentabiliser davantage consiste à optimiser les transferts thermiques en faisant évoluer le design du réacteur. Un échangeur-réacteur microstructuré a ainsi été retenu. Cet appareil de par la taille submillimétrique de ses canaux permet d'intensifier les transferts de chaleur et de matière. Cependant, la modification de l'architecture traditionnelle oblige à développer de nouveaux catalyseurs (MgAl2O4) déposables dans les microcanaux et permettant d'atteindre conversion élevées (80%, 20 bar, 850C) à faibles temps de passage (150 ms). La faisabilité du concept et la performance des catalyseurs ont été validées sur un canal dans les conditions industrielles du procédé. Un modèle de réacteur piston hétérogène a été utilisé pour estimer la cinétique de la réaction de reformage. Pour le design de l'échangeur-réacteur, deux approches de modélisation ont été développées en considérant l'équilibre thermodynamique à la surface du catalyseur ou en tenant compte du couplage entre la réaction et les transferts de chaleur et de matière. La simulation de ces modèles a permis de proposer la géométrie des canaux qui correspond au design optimal. Deux méthodologies de design ont été développées ainsi qu'un modèle permettant d'interpréter les résultats expérimentaux en tenant compte de la possibilité du bouchage des canaux. L'échangeur-réacteur fabriqué permet de réduire le coût de production pour une unité fonctionnant sans export de vapeurSteam Methane Reforming (SMR) of natural gas is characterized by generation of an excess of steam and their low thermal efficiency resulting in a very large device with important heat losses. One of the possible keys to make this process more profitable is to optimize heat transfer by changing the reactor design. A microstructured heat exchanger reactor has been retained. It enables to have fast heat and mass transfers and therefore allow increasing catalytic activity. However, this change in production technology must be accompanied by the development of highly active catalysts (MgAl2O4) that enable to reach high methane conversion (80%, 20 bar, 850C) at low residence time (150 ms). The concept feasibility and catalysts performance have been validated on one channel in industrial process conditions. Then, a detailed model for acquisition of reaction kinetics has been developed and validated from experimental catalytic tests. For heat exchanger reactor design, two modeling approaches have been developed: by considering that the catalyst is highly active and enables to reach instantaneous equilibrium conversion on the coated catalytic walls of the reactor and by tacking the measured kinetics. Simulation of these models by considering technical constraints on the design enabled to find channel characteristic dimensions, heat power needed and the optimum number of channel which determine the heat exchanger reactor volume. Two fast methods for preliminary design of heat-exchanger reactors have been developed. By using heat exchanger reactor, it is possible to suppress steam excess generation and to reduce syngas production costNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

Conception et caractérisation d'échangeurs-réacteurs à structuration multi-échelle

La présente thèse s intéresse à la conception et la caractérisation des procédés microstructurés mettant en œuvre des réseaux de microcanaux de différentes dimensions. L analyse de tels réseaux multi-échelles, représentatifs d une parallélisastion de microsystèmes élémentaires, a essentiellement servi à identifier les principaux paramètres géométriques et physiques contrôlant les performances de ces réseaux complexes. On a cherché à quantifier l influence des paramètres géométriques comme le rapport de résistances hydrodynamiques internes, le nombre de canaux et d échelles opérant ainsi que leur répartition sur le réseau, sur des critères hydrodynamiques comme la maldistribution du fluide et la perte de charge résistive. Il est révélé qu en fonction des contraintes imposées, un arrangement optimal des canaux sur un nombre pair d échelles permet de réduire considérablement la maldistribution interne des flux et les pertes de charge résultantes. L analyse thermique associée à l analyse hydrodynamique a montré que les performances thermiques des réseaux sont fortement liées à leurs structurations géométriques internes. En présence de réactions catalytiques consécutives, ces mêmes réseaux enregistrent des déviations du rendement du produit désiré. Ces déviations peuvent être levées par une structuration appropriée du réseau catalytique multi-canal. La même architecture de ces réseaux peut être adaptée pour permettre le déroulement des opérations de mélange et/ou des réactions multi-phasiques. Ainsi, pour ces réseaux complexes, où un nombre élevé de variables imbriquées est considéré, des lignes directrices sont ressorties pour aider à leur conception et dimensionnementThis PhD thesis focuses on the design and the characterization of microstructured processes including microchannel networks of various dimensions. The analysis of such multi-scale networks, representative of elementary microsystems parallelization, is mainly used to identify the main geometrical and physical parameters controlling the network performances. Influence of geometrical parameters, such as the internal hydrodynamic resistances ratio, the number of channels and scales and their arrangement in the network, on hydrodynamic criteria like fluid maldistribution and pressure drop is investigated. It is shown that according to some specific constraints, an optimal arrangement of the channels on an even number of scales, allows to reduce significantly the internal flow maldistribution and the consequential pressure losses. The thermal analysis coupled with the hydrodynamic analysis illustrates that the thermal performances of microchannel networks are strongly affected by their internal geometrical arrangement. Nevertheless, the various mixture points located in the network compensate the fluid maldistribution resulting from a non appropriate geometrical arrangement. When consecutive catalytic reactions are performed inside these networks, deviations of the desired product rate can be recorded. These deviations can be reduced by an optimal catalytic network arrangement. The same architecture of these networks is also adapted to allow multi-phase mixing and /or reactions. Thus, using these complex networks, where several variables are considered, guidelines are derived in order to improve their design and their dimensionlessNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

Preliminary design and simulation of a microstructured reactor for production of synthesis gas by steam methane reforming

International audienceThe present study considers the potentials of the well-known production of syngas by steam methane reforming (SMR), by operation within microstructured reactors. The model of a microchannel reactor is developed, including very fast kinetic reaction rates on the coated catalytic walls of the reactor module. By varying the characteristic dimensions of the channels, and considering technical constraints on the design and operating conditions, the results demonstrate that the SMR reactor can be drastically miniaturized while maintaining its productivity without any additional pressure drop. Furthermore, by reducing the channel characteristic dimensions, it is possible to suppress heat and mass-transfer limitations enabling SMR reactor operation at thermodynamic equilibrium. A fast method for preliminary design of microstructured heat-exchanger reactors is developed, that enables to identify the optimal channels number and heat power needed to reach process specifications

Methanol synthesis from CO2 and H2 in multi-tubular fixed-bed reactor and multi-tubular reactor filled with monoliths

International audienceThis work investigates the impact of catalyst structuring into particles or monoliths on methanol production from only CO2 and H2 at a large scale. Methanol synthesis in multi-tubular reactors is evaluated using packed-bed and monolithic reactors by modeling heat and mass transfer in each reactor. The obtained simulation results show that, at low gas hourly space velocity (GHSV = 10,000 h−1), the performances of both reactor technologies are similar. In this case, the packed-bed reactor technology is the most appropriate technology due to its simplicity of installation and operation. At high GHSV (25,000 h−1), the packed-bed reactor technology is limited by a considerable pressure drop that causes an important loss in productivity due to thermodynamic equilibrium, whereas the monolithic reactors exhibit negligible pressure drop and achieve far better performances