Journal: International Journal of Hydrogen Energy

Abbreviation

Int. J. Hydrogen Energy

Publisher

Elsevier

Journal Volumes

ISSN

1879-3487
0360-3199

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Publications 1 - 10 of 75
  • Hydrogen production by steam-gasification of petroleum coke using concentrated solar power—II Reactor design, testing, and modeling
    Item type: Journal Article
    Z'Graggen, Andreas; Haueter, Philipp; Trommer, D.; et al. (2006)
    International Journal of Hydrogen Energy
    The solar chemical reactor technology for the steam-gasification of petcoke is presented. The reactor features a continuous vortex flow of steam laden with petcoke particles confined to a cavity receiver and directly exposed to concentrated solar radiation. A 5 kW prototype reactor tested in a high-flux solar furnace in the range 1300–1800 K yielded up to 87% petcoke conversion in a single pass of 1 s residence time. The solar-to-chemical energy conversion efficiency attained 9% without accounting for the product's sensible heat, and 20% when the sensible heat is recovered for steam generation and pre-heating. A steady-state process model that couples radiative heat transfer with the reaction kinetics is validated with experimental data and used for optimization and scale-up of the reactor design.
  • Thermal and heat transfer dynamics in high pressure, high aspect ratio hydrogen tank filling processes
    Item type: Journal Article
    Couteau, Arthur; Alvarez, Henry Raymond; Jenny, Patrick; et al. (2025)
    International Journal of Hydrogen Energy
    A thermodynamic modeling framework is introduced to describe hydrogen refueling station configurations and capture detailed thermal dynamics in vehicle tanks with large aspect ratios. With an aspect ratio larger than three, axial discretization of temperature allows to recover accurate temperature profiles and show that the gas and liner temperature are always highest towards the rear of the tanks. The framework is validated against experimental data and used to investigate the internal heat transfer dynamics. As aspect ratio grows larger, the amount of cooling received by the rear region decreases as the incoming turbulent jet does not reach the latter. The current thermal management strategy of pre-cooling is therefore limited, showing marginal improvements, even with a cooling temperature of -50 °C. Potential solutions are to increase the filling duration time, or to carefully design the tank with higher thermal diffusivity and adequate external means of cooling.
  • Flow patterns and heat transfer characterization during large aspect ratio hydrogen tank filling
    Item type: Journal Article
    Couteau, Arthur; Dimopoulos Eggenschwiler, Panayotis; Jenny, Patrick (2025)
    International Journal of Hydrogen Energy
    Temperature management in high-pressure hydrogen tank filling is crucial, requiring detailed analysis of heat transfer physics. This study used 3D CFD simulations to examine how tank aspect ratio, filling time, and orientation affect heat transfer dynamics. Results show that turbulent jet flow extends approximately three tank diameters inward, creating a mixing zone between existing and incoming hydrogen. For tanks shorter than this mixing length, simplified thermodynamic models accurately predict temperature evolution due to uniform gas mixing. Longer tanks exhibit varied flow patterns requiring consideration of multiple heat transfer mechanisms. The present work reveals consistent flow and wall heat flux patterns across different aspect ratios, suggesting potential applications for extending thermodynamic models to diverse tank geometries. These findings contribute to understanding and optimizing high-pressure hydrogen filling processes, with implications for efficient tank design and operation.
  • A spatially-resolved temperature-dependent model for butane reforming over rhodium catalyst
    Item type: Journal Article
    Nabavi, Majid; Yan, Yan; Santis-Alvarez, Alejandro-Javier; et al. (2012)
    International Journal of Hydrogen Energy
  • Hetero-/homogeneous combustion of hydrogen/air mixtures over platinum
    Item type: Journal Article
    Schultze, M.; Mantzaras, J. (2013)
    International Journal of Hydrogen Energy
  • Hydrogen production by steam-gasification of carbonaceous materials using concentrated solar energy - IV. Reactor experimentation with vacuum residue
    Item type: Journal Article
    Z'Graggen, Andreas; Haueter, Philipp; Maag, Gilles; et al. (2008)
    International Journal of Hydrogen Energy
    The combined pyrolysis and steam-gasification of petroleum vacuum residue was performed using a 5-kW aerosol-flow solar chemical reactor tested in a high-flux solar furnace in the temperature range 1420-1567 K. The feedstock was continuously injected as a liquid spray at 423 K into the reactor's cavity along with a coaxial steam flow at a H2 O / C molar ratio in the 1.1-7.2 range, and directly exposed to concentrated solar radiation at concentration ratios exceeding 1800 suns. The degree of chemical conversion after a single pass of 1-s residence time attained 50% at 1472 K, producing high quality syngas of composition 68% H2, 15% CO, 14% CO2, and 2% CH4. The process performance indicators, namely, carbon conversion and energy efficiency were generally inferior to those obtained for the solar steam-gasification of petcoke under comparable operating conditions.
  • Life Cycle Assessment of Substitute Natural Gas production from biomass and electrolytic hydrogen
    Item type: Journal Article
    Bargiacchi, Eleonora; Candelaresi, Daniele; Valente, Antonio; et al. (2021)
    International Journal of Hydrogen Energy
    The synthesis of a Substitute Natural Gas (SNG) that is compatible with the gas grid composition requirements by using surplus electricity from renewable energy sources looks a favourable solution to store large quantities of electricity and to decarbonise the gas grid network while maintaining the same infrastructure. The most promising layouts for SNG production and the conditions under which SNG synthesis reduces the environmental impacts if compared to its fossil alternative is still largely untapped. In this work, six different layouts for the production of SNG and electricity from biomass and fluctuating electricity are compared from the environmental point of view by means of Life Cycle Assessment (LCA) methodology. Global Warming Potential (GWP), Cumulative Energy Demand (CED) and Acidification Potential (AP) are selected as impact indicators for this analysis. The influence of key LCA methodological aspects on the conclusions is also explored. In particular, two different functional units are chosen: 1 kg of SNG produced and 1 MJ of output energy (SNG and electricity). Furthermore, different approaches dealing with co-production of electricity are also applied. The results show that the layout based on hydrogasification has the lowest impacts on all the considered cases apart from the GWP and the CED with SNG mass as the functional unit and the avoided burden approach. Finally, the selection of the multifunctionality approach is found to have a significant influence on technology ranking.
  • Hydrogen production by steam-gasification of carbonaceous materials using concentrated solar energy – V. Reactor modeling, optimization, and scale-up
    Item type: Journal Article
    Z'Graggen, Andreas; Steinfeld, Aldo (2008)
    International Journal of Hydrogen Energy
  • A novel beam-down, gravity-fed, solar thermochemical receiver/reactor for direct solid particle decomposition
    Item type: Journal Article
    Koepf, Erik; Advani, Suresh G.; Steinfeld, Aldo; et al. (2012)
    International Journal of Hydrogen Energy
  • Solar hydrogen production via a 2-step water-splitting thermochemical cycle based on Zn/ZnO redox reactions
    Item type: Journal Article
    Steinfeld, Aldo (2002)
    International Journal of Hydrogen Energy
Publications 1 - 10 of 75