1,721,058 research outputs found
Structured catalysts for natural gas reforming
No full textHydrogen is a zero-carbon energy carrier for the deployment of fuel cell technologies in distributed energy systems and offers great potential in the transition toward a low-carbon economy. In addition to improved energy efficiency, hydrogen fuel cells can improve air quality with negligible emission of harmful particulates and nitrogen oxides. Hydrogen can be produced from a variety of feedstocks, such as non-renewable and renewable resources using electrolysis and reforming processes. Methane is the main component of large distributed renewable (e.g., biomethane, biogas) and nonrenewable (e.g., natural gas, shale gas) feedstocks, and up to now the reforming of methane is the most suitable and easy way to produce hydrogen.
Methane steam reforming (MSR) is a mature technology, dominant at an industrial scale supplying 40% of world’s hydrogen, with benefits of higher hydrogen yield and concentration in the product stream as compared to other reforming technologies. MSR is a highly endothermic reaction, requiring a large amount of heat at temperatures up to 1000 °C25 for attractive equilibrium conversion, which makes a high-temperature catalytic combustor desirable. The scaled-down version of industrial reformers shows poor performance and responds slowly to throughput variation, mainly because of heat transfer limitations between the flame and the catalyst pellet, and also due to mass transfer limitations. By improving transport limitations, microreactor technology and structured catalysts provide unique opportunities to realize compact and modular steam reformers. In fact, the improved heat and mass transport rates lead to 1−3 times higher throughput of hydrogen.
This review will highlight the emerging technologies in terms of structured reactors for the production of syngas via MSR
The Special issue of HYCELTEC2024 - IX International Symposium on Hydrogen, Fuel Cells and Advanced Batteries
No full textSynthesis of a NNM catalyst active towards ORR in alkaline media through sulfur optimization in organic non polar solvent for DEFCs applications
No full textPure hydrogen production from natural gas via fuel processor based on steam reforming with WGS and PSA units
No full textH2 is produced mostly from reforming of fossil fuel followed by a series of purification steps. This work is a sensitivity analysis of H2 production plant from natural gas. The plant consists of steam reforming, a water gas shift, and a pressure swing adsorption units to produce high-purity H2. The sensitivity analysis was carried our varying the percentage of H2 recovery from the PSA (70-75%) and the operating pressure (5-30 bar,g), in order to identify the best operative conditions that provide the best equilibrium between H2 production and the overall efficiency of the system
Editorial article on the publications from the IX Symposium on Hydrogen, Fuel Cells and Advanced Batteries, HYCELTEC 2024
No full textUnderstanding the role of carbon morphology in sulfonated silica ceramic carbon electrodes for pem fuel cell devices
No full textSynthesis and process optimization of a non-noble metal catalyst for oxygen reduction reaction in alkaline solution based on iron phthalocyanine and zeolitic imidazolate framework
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
