Patrick Langlois

This study provides a comprehensive overview of research and advancements on carbon materials with regard to practical targets for hydrogen storage in terms of gravimetric and volumetric capacities. For the sake of clarity, only the most relevant references on hydrogen storage by adsorption are presented, although the study was conducted in the same exhaustive manner as the one initially carried out by Anne C. Dillon and Michael J. Heben in 2001 with a particular emphasis on emerging technologies and potential applications in various sectors. This study also focuses on the importance of carbon-based materials with high specific surface areas and porous structures optimised to maximise adsorption—including at high pressure—while primarily limiting references herein to experimentally validated results. It therefore offers insights into the porous materials, as well as the methodologies—including a fully comprehensive and so-far proven highly transferable intermolecular hydrogen model combining van der Waals’s and Coulomb’s forces—used to improve hydrogen solid storage efficiency.

This study provides a comprehensive overview of research and advancements on carbon materials with regard to practical targets for hydrogen storage in terms of gravimetric and volumetric capacities. For the sake of clarity, only the most relevant references on hydrogen storage by adsorption are presented, although the study was conducted in the same exhaustive manner as the one initially carried out by Anne C. Dillon and Michael J. Heben [Appl. Phys. A 2001, 72, 133–142] with a particular emphasis on emerging technologies and potential applications in various sectors, and focusing on the importance of carbon-based materials with high specific surface areas and porous structures optimised to maximise adsorption — including at high pressure —, while primarily limiting references herein to experimentally validated results. It therefore offers insights into the porous materials as well as the methodologies — including a fully comprehensive and so far proven highly transferable intermolecular hydrogen model combining van-der-Waals's and Coulomb's forces — used to improve hydrogen solid storage efficiency.

As part of the ongoing transition from fossil fuels to renewable energies, advances are particularly expected in terms of safe and cost-effective solutions. Publicising instances of such advances and emphasising global safety considerations constitute the rationale for this communication. Knowing that high-strength steels can prove economically relevant in the foreseeable future for transporting hydrogen in pipelines by limiting the pipe wall thickness required to withstand high pressure, one advance relates to a bench designed to assess the safe transport or renewable-energy-related buffer storage of hydrogen gas. That bench has been implemented at the technology readiness level TRL 6 to test initially intact, damaged, or pre-notched 500 mm-long pipe sections with nominal diameters ranging from 300 to 900 mm in order to appropriately validate or question the use of reputedly satisfactory predictive models in terms of hydrogen embrittlement and potential corollary failure. The other advance discussed herein relates to the reactivation of a previously fruitful applied research into safe mass solid-state hydrogen storage by magnesium hydride through a new public–private partnership. This latest development comes at a time when markets have started driving the hydrogen economy, bearing in mind that phase-change materials make it possible to level out heat transfers during the absorption/melting and solidification/desorption cycles and to attain an overall energy efficiency of up to 80% for MgH₂-based compacts doped with expanded natural graphite.

In the ongoing transition from fossil fuels to renewable energies, advances are particularly expected regarding safe and cost-effective solutions. Publicising instances of such advances and emphasising safety considerations constitute the rationale for this communication. Knowing that high-strength steels can prove economically relevant for transporting hydrogen in pipelines by limiting the pipe wall thickness required to withstand high pressure, one advance relates to a bench designed for contributing to study the safety of the gaseous transport or renewable-energy-related buffer storage of hydrogen. That bench has been specifically implemented at technology readiness level TRL 6 for testing initially intact, damaged, or pre-notched DN 300/NPS 12, DN 600/NPS 24, and DN 900/NPS 36 pipe sections in order to provide data allowing for the possible validation of fully satisfactory predictive models in terms of hydrogen embrittlement and potential corollary ruin. The other advance relates to the reactivation of a previously fruitful applied research into mass solid-state hydrogen storage through a new public-private partnership. This latest development comes at a time when markets have started driving the hydrogen economy, bearing in mind that phase-change materials decisively allow levelling the heat transfers during the absorption/melting and solidification/desorption cycles and attaining an overall energy efficiency of up to 80% for MgH₂-based compacts doped with expanded natural graphite.

Biomass as a whole offers a more diverse potential for valorisation than any other renewable energy source. As one of the stages in the separation of bio-oil involves a liquid mixture of acetol and acetic acid, and as both components are particularly well suited for valorisation, a hybrid method was developed for their separation with a high purity level through an approach combining liquid–liquid extraction and distillation. In order to design and simulate the flowsheet, the ChemCAD 7.0 simulation software was used. Sensitivity analyses were carried out to investigate the influence of the different parameters in the distillation columns, such as the reflux ratio, the feed stage location, and the vapour/bottom molar flow ratio. The effect of different extractants and of their excess on the separation process, as well as the possibility of regenerating the extractant, was also studied. Tri-n-octylamine was accordingly selected as a separating agent that was fully recycled. The end result for separating an initial 48/52 wt% acetol/acetic acid liquid mixture was acetol with a purity of 99.4 wt% and acetic acid with a purity of 100 wt%.

Biomass as a whole offers a more diverse potential for valorisation than any other renew-able energy source. As one of the stages in the separation of bio-oil involves the liquid mixture of acetol and acetic acid, and as both components are particularly well suited for valorisation, a hybrid method has been developed for their separation with a high purity level through an approach combining liquid-liquid extraction and rectification. In order to design and simulate the flowsheet, the ChemCAD 7.0 simulation software has been used. Sensitive analyses have been carried out to investigate the influence of the different pa-rameters in the rectification columns such as the reflux ratio, the feed stage location, and the vapour/bottom molar flow ratio. The effect of different extractants and of their excess on the separation process as well as the possibility of regenerating the extractant has also been studied. Tri-n-octylamine has accordingly been selected as a separating agent which has been fully recycled. The end result for separating an initial 48/52 wt% ace-tol/acetic-acid liquid mixture has been acetol with a purity of 99.4 wt% and acetic acid with a purity of 100 wt%.

Au XIX e siècle, l’avènement de la machine à vapeur a permis un remarquable développement des transports et de l’industrie. Cette vapeur capable de fournir directement de l’énergie mécanique mais qui n’existe pas comme telle dans la nature – il faut la produire en chauffant de l’eau – était le premi

En tant que combustible, l’hydrogène est utilisé ou utilisable soit en combustion directe, soit dans les piles à combustible qui produisent de l’électricité à des puissances allant de 10 mW à 10 MW. Ses applications vont des équipements portables aux procédés industriels gros consommateurs

Le frettage constitue un mode d’assemblage direct dont l’essor tient à sa versatilité. Réalisable à chaud, à froid ou à la presse, sur de petits ou de très grands assemblages de matériaux identiques ou non et de géométries diverses, pour des applications statiques ou dynamiques, ce procédé ne cesse

In order to study the purification of hydrogen and its separation from gas mixtures by adsorption, different models describing the adsorption equilibrium of gas mixtures have been tested; seven of them have been compared with experimental multi-component data obtained from the literature. The measurements include three-component mixtures of hydrogen, nitrogen, and methane. All the models used in this study are purely predictive; such models are competitive isotherm models which use only the previously obtained coefficients of the single-component isotherms. A mathematical description of each model is developed and discussed. Based on the results of numerical experiments, an analysis of how best to apply the Sips multi-component approach and the Ideal Adsorbed Solution theory is developed. A discussion on the ability and accuracy of the different models to describe the multi-component adsorption equilibria is developed. Based on this research, the Jovanovic model, which best reproduces the experimental results of the adsorption equilibrium in all cases, can be recommended as the most appropriate to use.