Daniel Tondeur

Bio: Daniel Tondeur is an academic researcher from Centre national de la recherche scientifique. The author has contributed to research in topics: Pressure swing adsorption & Adsorption. The author has an hindex of 28, co-authored 104 publications receiving 2510 citations. Previous affiliations of Daniel Tondeur include Nancy-Université & Elf Aquitaine.

Dynamics of Fixed-Bed Adsorbers

Abstract: Let us observe the concentration profiles (concentration in fluid phase, say, versus abscissa in bed from inlet) in the adsorbent bed of Figure la, when the adsorbent is initially clean (1) and receives a feed of constant concentration in some adsorbable species A (the solute).

Carbon Capture and Storage for Greenhouse Effect Mitigation

Abstract: Publisher Summary The capture of carbon dioxide from flue gases of industrial combustion processes and its storage in deep geological formations is now being seriously considered as one of the options for mitigating climate change. This chapter presents the overall background on which this approach is based, then reviews the different capture technologies and finally discusses the different options for underground storage. Carbon dioxide is responsible for about 60% of the present-day additional radiative forcing in the atmosphere. CCS has an important and inevitable energy cost, implying that when it is applied, more primary energy is needed and, ultimately, more CO2 is generated to produce a given amount of final energy. Carbon dioxide capture has been applied to industrial gas streams for almost a century, for process purposes but not for storage purposes. The main applications were “sweetening” of natural gas and treatment of “synthesis gas” for the manufacture of ammonia and methanol. In the present context, CO2 captures producing a concentrated stream of CO2, suitable for transport and subsequent storage, starting with dilute effluents. There are a number of potential geological reservoirs that can be considered as storage options for captured CO2. These storage options include depleted oil and gas fields, CO2 enhanced oil recovery (EOR), CO2 enhanced gas recovery (EGR), CO2 enhanced coal-bed methane recovery (ECBM), deep saline aquifers and other storage options. There is little experience of combining capture, transport and storage of CO2 in a fully integrated system, and none applied to large-scale power plants.

Optimisation thermodynamique: Équipartition de production d'entropie

Abstract: appelons que le second principe de la thermodynamique stipule que dans R tout processus reel, donc irreversible, la production d'entropie nette est positive. Cette quantite, qui s'exprime en joules par kelvin (ou en W. K -1 s'il s'agit d'une puissance), est donc une mesure naturelle et generale de l'irreversibilite d'un processus. Lorsque l'on s'interesse aux irreversibilites liees aux phenomenes purement thermiques, l'entropie est la seule fonction thermodynamique appropriee pour ce faire, car elle est la grandeur extensive « conjuguee » a la grandeur intensive temperature. Dans certains autres cas, d'autres grandeurs peuvent jouer ce role, notamment des grandeurs energetiques, donc exprimees en J ou en W, comme la dissipation visqueuse dans des ecoulements, ou bien la dissipation par effet Joule en electricite, ou encore la chaleur degagee par une reaction chimique irreversible. Dans tous ces cas, on mesure en fait une quantite de chaleur generee par la degradation irreversible d'une forme noble d'energie (mecanique ou electrique ou chimique dans ces exemples). Il est toujours possible, mais pas necessaire, de se ramener a une entropie en divisant cette energie thermique generee par une temperature de reference convenablement choisie. L'exergie est egalement une grandeur homogene a une energie, et dont la destruction est une mesure de l'irreversibilite. Nous consacrerons quelques pages a rappeler et clarifier les rapports entre cette grandeur et la production d'entropie. Nous nous interessons donc a des procedes et systemes qui ne sont pas ideaux au sens de la reversibilite. On concoit intuitivement que les irreversibilites sont « mauvaises » pour les performances, car elles degradent une forme d'energie, et on cherche donc toujours, explicitement ou implicitement, a les minimiser. Le probleme est que si on ne prend pas certaines precautions, cette minimisation conduit a des dimensionnements de procedes et/ou des conditions operatoires completement irrealistes et depourvues de tout interet pratique, comme par exemple des dimensions de surfaces de transfert qui deviennent tres grandes ou des vitesses de processus extremement lentes. Prendre des precautions, cela signifie ici imposer que toutes les grandeurs physiques soient finies, et que les tâches utiles attendues du procede soient bien effectuees. Cette approche definit ce que l'on appelle aujourd'hui « la thermodynamique en temps fini ou en dimension finie » ou encore a tâche finie (§ 1). La thermodynamique des processus irreversibles propose un cadre rigoureux, sinon commode, pour exprimer et etudier la production d'entropie, notamment dans sa version lineaire, ou les flux (de matiere, d'electricite, de quantite de mouvement, d'energie thermique) sont des fonctions affines des forces motrices (gradients de potentiel chimique, electrique, de vitesse, d'inverse de temperature). Nous nous placerons la plupart du temps dans ce cadre lineaire pour etablir des proprietes structurelles des procedes optimises, et notamment la propriete d'equipartition. La minimisation des irreversibilites se fera alors en integrant ces contraintes de finitude dans les calculs d'optimisation. La methode des multiplicateurs de Lagrange est particulierement commode pour cela, bien que des approches plus directes soient parfois possibles.

Entropy generation minimization: The new thermodynamics of finite-size devices and finite-time processes

Abstract: Entropy generation minimization (finite time thermodynamics, or thermodynamic optimization) is the method that combines into simple models the most basic concepts of heat transfer, fluid mechanics, and thermodynamics. These simple models are used in the optimization of real (irreversible) devices and processes, subject to finite‐size and finite‐time constraints. The review traces the development and adoption of the method in several sectors of mainstream thermal engineering and science: cryogenics, heat transfer, education, storage systems, solar power plants, nuclear and fossil power plants, and refrigerators. Emphasis is placed on the fundamental and technological importance of the optimization method and its results, the pedagogical merits of the method, and the chronological development of the field.

Adsorbents: Fundamentals and Applications

Abstract: Preface. 1. Introductory Remarks. 2. Fundamental Factors for Designing Adsorbent. 3. Sorbent Selection: Equilibrium Isotherms, Diffusion, Cyclic Processes, and Sorbent Selection Criteria. 4. Pore Size Distribution. 5. Activated Carbon. 6. Silica Gel, MCM, and Activated Alumina. 7. Zeolites and Molecular Sieves. 8. &pi -Complexation Sorbents and Applications. 9. Carbon Nanotubes, Pillared Clays, and Polymeric Resins. 10. Sorbents for Applications. Author Index. Subject Index.

Pressure swing adsorption

Abstract: A pressure swing adsorption cycle comprised of blowdown, purge, pressurization, feed, pressure equalization and rinse steps provided recovery from an atmospheric air feed, essentially dry and free of carbon dioxide, of a high yield of high purity nitrogen gas and a high yield of a product gas rich in oxygen as well as recovery of a residual feed byproduct gas for recycle with the air feed.

Methane storage in flexible metal–organic frameworks with intrinsic thermal management

Abstract: Two flexible metal-organic frameworks are presented as solid adsorbents for methane that undergo reversible phase transitions at specific methane pressures, enabling greater storage capacities of usable methane than have been achieved previously, while also providing internal heat management of the system. Natural gas — methane — is a clean and cheap fuel but its usefulness in transport applications is limited by storage problems, given its low energy density per unit volume under ambient conditions compared with petrol or diesel. One way of increasing methane storage capacity is to use tanks containing porous materials, such as metal–organic frameworks, as a storage medium. However, for every methane molecule adsorbed and desorbed there is an associated thermal fluctuation that could cause overheating or reduce storage efficiency if left unchecked. Here Jeffrey Long and colleagues describe two flexible metal–organic frameworks that undergo reversible phase transitions at specific methane pressures, enabling greater storage capacities of usable methane than have been achieved previously, while also providing internal heat management of the system. As a cleaner, cheaper, and more globally evenly distributed fuel, natural gas has considerable environmental, economic, and political advantages over petroleum as a source of energy for the transportation sector1,2. Despite these benefits, its low volumetric energy density at ambient temperature and pressure presents substantial challenges, particularly for light-duty vehicles with little space available for on-board fuel storage3. Adsorbed natural gas systems have the potential to store high densities of methane (CH4, the principal component of natural gas) within a porous material at ambient temperature and moderate pressures4. Although activated carbons, zeolites, and metal–organic frameworks have been investigated extensively for CH4 storage5,6,7,8, there are practical challenges involved in designing systems with high capacities and in managing the thermal fluctuations associated with adsorbing and desorbing gas from the adsorbent. Here, we use a reversible phase transition in a metal–organic framework to maximize the deliverable capacity of CH4 while also providing internal heat management during adsorption and desorption. In particular, the flexible compounds Fe(bdp) and Co(bdp) (bdp2− = 1,4-benzenedipyrazolate) are shown to undergo a structural phase transition in response to specific CH4 pressures, resulting in adsorption and desorption isotherms that feature a sharp ‘step’. Such behaviour enables greater storage capacities than have been achieved for classical adsorbents9, while also reducing the amount of heat released during adsorption and the impact of cooling during desorption. The pressure and energy associated with the phase transition can be tuned either chemically or by application of mechanical pressure.