Gotowa bibliografia na temat „End-Of-Pipe catalytic system”

Catalytic conversions in fine-chemical and pharmaceutical production are increasingly performed in trickle-bed rectors. Optimisation of these processes is usually based on end of pipe measurement made at specific residence times. This process is both time-consuming and the data sometimes challenging to interpret. In the present work, operando nuclear magnetic resonance (NMR) techniques both at the scale of the whole bed (global) and spatially resolved within the bed (local) are used to gain new insights into the catalytic conversion process under reaction conditions. Spatially resolved spectroscopic and diffusion-T2-relaxation (D-T2) methods interrogate local differences in chemical conversion and selectivity, and mass transport (molecular self-diffusion) respectively, thereby providing valuable information for process simulation models. This capability is demonstrated using the continuous flow three phase (gas-liquid-solid) hydrogenation of benzonitrile over a fixed bed of 0.5 wt% Pd/Al2O3 catalyst pellets yielding toluene and benzylamine. Global 1H spectroscopic and D-T2 were used to monitor chemical conversion and the approach to steady state; these were subsequently followed by spatially resolved 1H spectra and spatially resolved D-T2 correlations to examine the local differences in axial conversion and selectivity of the catalyst bed packing. At steady-state a global conversion of 63% was achieved with 65% and 25% selectivity to benzylamine and toluene respectively. Heterogeneities in the local (axial) conversion and selectivity differed by 31% along the total catalyst bed length. These techniques should be applicable to many three-phase heterogeneous catalytic systems provided that the T2 relaxation time of the reactants and products is not prohibitively small.

In the last two and a half centuries, industrialization, propelled by a catalytic impact of free-market capitalism, has been contributing to prosperity and breaking the limits beyond all imagination that during the history inhibited the development of human potential. Unfortunately, neoliberal capitalism, as the last and most extreme variant of free-market capitalism, has shown some hidden fractures. After the Great Recession of 2008, the problems due to inbuilt fault lines and misconceptions erupted to the surface. Over the last two years, marked by the COVID-19 pandemic, the world economy has been passing through a complex crisis, a crisis within the spectrum of crises. Again, the flip side of a major success proved to be a major failure. The new virus simply magnified and accelerated doom and gloom in the economic system. The major strategic shifts such as climate crisis, structural crisis of capitalism, microbe mutations and superinfections, and, particularly, the Fourth Industrial Revolution, have contributed jointly to the disruption of incumbents in business, regulatory settings and society as a whole. Exponential change is the New Normal. The economic system is simply surrounded with exponentiality. Neoliberal capitalism has definitely hurt sustainability, along with renewability and inclusivity, of the global economic system and the entire planet. In a time of the explosion of systemic, climate and biological risks, a delicate and subtle issue has emerged as to how to adjust the existing system to exponential change conceptually, financially and operationally. In fact, the current economic system is not able to adequately respond to exponential challenges by transforming threats into opportunities. In times of the climate crisis, the pandemic is just the tip of the iceberg which, by the way, is melting away. The COVID-19 is not a perpetual virus. Someday the pandemic will end. In fact, the transition from pandemic to endemic is imminent. Accordingly, in the post-pandemic world key performance will be the capacity of a new economic system to respond positively to ever-increasing old challenges, in particular to the climate emergency and related issues. So, the green transition is an imperative of modern Economics. At the start of the pandemic, most governments relied on expansionary monetary and fiscal policies with the aim of relaxing the "fear of fear" (unspent savings and pent-up demand). During the crisis money pumping was about US$ 13 trillion on a global level. The continuation of this policy has pushed the world economy into an unstable mode because it leads to an increase in aggregate demand that largely exceeds the supply level, drives wage-price spirals and deepens other structural imbalances. In the context of extremely low or even negative interest rates, economic agents take an extra high credit risk and the state takes an unmanageable sovereign risk. Consequently, today's debt in many core economies is substantially higher than in any previous stagflation episode. When the inflation risk premium pushes interest rate hikes, public and private agents with an increasing debt burden and lower earnings face insolvency threat due to such a hawkish turn. Among many negative scenarios, overheating and stagflation followed by growing indebtedness are the most dangerous outcomes. Given today's ultra-loose and even costly anti-crisis core economic policies, the confidence in the "invisible hand" of the market and unconventional and experimental economic policies, praised by mainstream economists as a panacea for all imbalances, has definitely disappeared and may be easily turned into a pipe dream everywhere. There is not much time to respond to the New Normal. Humanity has less than a decade left until climate change becomes irreversible. The response should be prompt, comprehensive and compatible with exponential change. So, mitigation of a complex crisis requires the consideration of more radical ideas. Without a paradigm change, the economy will not be able to resolve the current crisis and work in a sustainable and inclusive way for the sake of people and nature in a rapidly changing context of the New Normal. Every crisis is a catalyst for change. To reimagine the economy, apart from the shift to the circular model of growth and heterodox economic policy platform, public governance must change, too. Moreover, to take advantage of the leading trends, the economic system must follow substantially different economics rules in many fundamental aspects. In an emerging system, the government and basic economic agents will work symbiotically with the aim of serving nature and human needs through industrial policies and impact investments, devoting concerted efforts to coordination and fostering experimentation on all levels. Automatic macroeconomic stabilizers will play the role of a liaison between structural and core economic policies by maintaining a sustainable balance between private and public sectors. In Industry 4.0, governance should also respect the sustainable development goals, as well as environmental, social and governance metrics arising from mission-oriented governance or Governance 4.0. The aforementioned does not mean that after the paradigm change we will have a new precisely defined blueprint that will tell us in detail what to do. Economics is not big science, but a social or contextual science. In the age of Industry 4.0 characterized by endless innovative amalgams arising from the intersection of breakthroughs in AI, robotics, and life science, Economics can treat the economic system only as a nonlinear one. So, what the paradigm shift brings to the emerging contours of new Economics is not a new theory, but the nexus of new rules we can follow in the context of exponential change. The purpose of this paper is not to endorse, but to discuss the subject from the title with a special focus on Serbia. Our intention is just to provide the overview of emerging intellectual trajectories relevant to the current crisis mitigation and to sketch out the nexus of economics rules that will pave the way for a resilient, sustainable and inclusive economy. A common concern is related to the circular economy growth model and heterodox economic policy platform because both elements are able to address the key pressing issues in times of exponential change. Bearing in mind that Serbia does not have a significant fiscal space or fully convertible currency, on the one hand, and the lack of retained earnings in the private sector and valuesubtracted public sector, on the other, the key issue for Serbia's future strategy is going to be fixing the green transition finance. The paper is structured in four parts, except Introduction and Conclusion. In the first part we review the neoliberal economics rules and associated policies as well as the unconventional policies that were intended to address the challenges brought by the Great Recession of 2008. In the second part we point to the fallacies and contradictions of the experimental policies measures implemented during the COVID-19 crisis and call for a turnaround in the economic system. The contours of a new economic system based on a completely different nexus of economics rules and policies arising from the circular economy growth model and heterodox economic policy platform are described in the third part. Finally, in the fourth part we portray the key macroeconomic trends in Serbia's economy in 2021 and identify the areas that need restructuring in order to be ready for a transition toward a climate-minded and health-minded economy.

AbstractNon-thermal plasmas are innovative and promising tools with respect to end-of-pipe treatment of waste gases. Among other features, they allow decomposition of low concentrations of volatile organic compounds in air streams at atmospheric pressure. In this paper, a plasma-catalytic hybrid system for the removal of trichloroethylene (TCE) in dry air is discussed. A pin-to-mesh electrode concept is used to obtain a positive corona discharge. A packed bed of TiO

AbstractClose-coupled selective catalytic reduction (SCR) systems are one method to deal with tightening emission legislation for NOx in internal combustion engines. Due to smaller mixing sections and at unfavourable boundary conditions, however, urea-water solution (UWS) droplets can impact on the SCR catalyst itself. To investigate this phenomenon further, this work develops a modeling capability of this process. Established mechanism for NH3-SCR and HNCO hydrolysis from literature is integrated into DETCHEMCHANNEL and a 2D COMSOL model to simulate the influence in the SCR Channel. Simulations are validated against end-of-pipe experiments from literature and spatially resolved concentration profiles from a hot gas test rig with very good agreement. Finally, a channel simulation is coupled with a model to describe the catalytic decomposition of an urea droplet. The coupled simulation is able to simulate the influence of UWS droplet impact onto a catalyst channel. Fast droplet decomposition causes a peak in NH3 and HNCO in the single channel and thus increases NOx conversion. However, the overall uniformity and efficiency are decreased, which is why droplet impact on the catalyst should be strictly avoided.

L'objectif de ces travaux de thèse est pour développer les catalyseurs à base de pérovskite et palladium pour le traitement des traces de méthane issues des véhicules fonctionnant au gaz naturel. Plus en détail, l'étude est basée sur la combinaison de deux catalyseurs actifs ayant chacun un rôle dans la réaction visée - la combustion catalytique de méthane. Les pérovskites à base de composition LaMnO3 avec une excellente activité d'oxydation du méthane à haute température sont utilisées comme supports. Parmi eux, l'étude non-stœchiométrique du lanthane et les substitutions partielles du lanthane par le potassium et le strontium ont été utilisés pour modifier la structure de la pérovskite afin de générer des distorsions pour une meilleure activité catalytique et une meilleure mobilité de l'oxygène. Le palladium, reconnu comme un métal noble avec d'excellentes performances catalytiques du méthane à basse température, a été incorporé aux catalyseurs pérovskites par différentes méthodes de calcination (c'est-à-dire la méthode one-pot et la méthode séquentielle par la voie de synthèse de la méthode sol-gel de l'acide citrique). Compte tenu de la prise en compte de la maîtrise des coûts, l'objectif est de réduire au maximum l'utilisation du palladium, de 1% à 0.5% en masse dans l'expérimentation. Par conséquent, le système catalytique composite de pérovskite boosté par la faible teneur en palladium est la stratégie de recherche de ce sujet autour de la combustion catalytique de méthane. Afin d'étudier les propriétés physico-chimiques des catalyseurs, les méthodes de caractérisation telles que l'analyse thermogravimétrique, la diffractométrie de rayons X, la N2-physisorption, la H2-réduction en température programmée, la O2-oxidation en température programmée, la O2-désorption programmée en température/spectrométrie de masse, la microscopie électronique à balayage/spectroscopie de rayons X à dispersion d'énergie, la microscopie électronique en transmission/spectroscopie de rayons X à dispersion d'énergie, la spectrométrie photoélectronique X et la spectrométrie de masse à plasma à couplage inductif sont utilisées pour analyser les propriétés de surface et de bulk des catalyseurs cibles.La deuxième partie de cette thèse a été consacrée à la cinétique de l'oxydation de méthane par la route de réactions à haut débit. L'étude de la cinétique a été effectuée par l'approche à travers la combinaison théorique et expérimentale pour étudier les mécanismes des différentes propositions des sites actifs et la source d'espèces réactives de l'oxygène actif avant et après vieillissement. De plus, dans tout le processus de réaction, les catalyseurs avec différentes méthodes d'incorporation de palladium présentent les mécanismes de réaction différents. Cette étude est instructive pour d'étudier la nature et la synergie de l'oxydation de méthane sur la pérovskite boostée par palladium et les facteurs influençant la conception des catalyseurs.En pratique, cette combinaison des catalyseurs a été utilisée comme catalyseurs à trois voies pour le post-traitement de gaz simulé des moteurs à gaz naturel. Les catalyseurs ont été testé dans le réacteur de plug-flow à l'échelle du laboratoire selon le même plan expérimental comme la partie cinétique. Dans le courant des traces de méthane, la réaction devient plus difficile et plus compliquée en présence de NO, CO, vapeur d'eau et CO2. L'oxydation complète du méthane, l'oxydation partielle du méthane, la réduction du NO à l'azote ou même à l'ammoniac ont été découvert et investigué par le bilan de réaction.Mots-clés : Pérovskite / Oxydation de méthane / palladium / post-traitement catalytique / moteur au gaz naturel
The objective of this thesis work is to develop catalysts based on perovskite and palladium for the treatment of traces of methane from vehicles running on natural gas. In more detail, the study is based on the combination of two active catalysts, each having a role in the targeted reaction - the catalytic combustion of methane. Perovskites based on LaMnO3 composition with excellent high temperature methane oxidation activity are used as carriers. Among them, the non-stoichiometric study of lanthanum and the partial substitutions of lanthanum by potassium and strontium have been used to modify the structure of perovskite to generate distortions for better catalytic activity and mobility of the oxygen. Palladium, recognized as a noble metal with excellent low temperature methane catalytic performance, has been incorporated into perovskite catalysts by different calcination methods (i.e. one-pot method and sequential method by synthesis of the sol-gel method of citric acid). Given the consideration of cost control, the objective is to reduce the use of palladium as much as possible, from 1% to 0.5% by mass in the experiment. Therefore, low palladium boosted perovskite composite catalytic system is the research strategy of this topic around catalytic methane combustion. In order to study the physicochemical properties of catalysts, characterization methods such as thermogravimetric analysis, X-ray diffractometry, N2-physisorption, H2-temperature-programmed reduction, O2-temperature-programmed oxidation, O2-temperature-programmed desorption/mass spectrometry, scanning electron microscopy/energy dispersive X-ray spectroscopy, transmission electron microscopy/energy dispersive X-ray spectroscopy, X-ray photoelectron spectrometry and Inductively Coupled Plasma Mass Spectrometry are used to analyze surface and bulk properties of target catalysts.The second part of this thesis was devoted to the kinetics of methane oxidation by the high-throughput reaction method. The study of the kinetics was carried out by the approach through the theoretical and experimental combination to study the mechanisms of the different proposals of the active sites and the source of reactive species of active oxygen before and after aging. Moreover, in the whole reaction process, the catalysts with different palladium incorporation methods exhibit the different reaction mechanisms. This study is instructive to investigate the nature and synergy of methane oxidation on palladium-boosted perovskite and the factors influencing catalyst design.In practice, this combination of catalysts has been used as three-way catalysts for simulated gas aftertreatment of natural gas engines. The catalysts were tested in the laboratory-scale plug-flow reactor according to the same experimental plan as the kinetic part. In the current of methane traces, the reaction becomes more difficult and more complicated in the presence of NO, CO, water vapor and CO2. The complete oxidation of methane, the partial oxidation of methane, the reduction of NO to nitrogen or even to ammonia have been discovered and investigated by the reaction budget.Keywords: Perovskite / Methane Oxidation / Palladium / Catalytic Aftertreatment / Natural Gas Engine