Microwave-assisted CO2 reforming of coke oven gas: An exception to the general rule?

It has been previously reported that the dry reforming of methane can be enhanced by means of microwave heating. In this article, this technology is applied to the CO2 reforming of coke oven gas (COG). The results obtained were opposite to those reported in the CO2 reforming of CH4, since in the case of the COG, microwave heating only slightly enhanced the conversions when an activated carbon was used as catalyst, whereas the results achieved when mixtures of activated carbon and Ni/Al 2O3 were employed as catalyst were even worse than those obtained in a conventional oven. Several hypotheses were considered in order to find an explanation for these poor results, the nature of the microplasmas formed during the process being the most likely factor. The high proportions of H2 present in the reactor when the dry reforming of coke oven gas is carried out may give rise to microplasmas of higher temperature than in the dry reforming of CH4. This will cause the Ni particles to sinter significantly, leading to a decrease in the conversions

Microwave-assisted CO2 reforming of coke oven gas: An exception to the general rule?

It has been previously reported that the dry reforming of methane can be enhanced by means of microwave heating. In this article, this technology is applied to the CO2 reforming of coke oven gas (COG). The results obtained were opposite to those reported in the CO2 reforming of CH4, since in the case of the COG, microwave heating only slightly enhanced the conversions when an activated carbon was used as catalyst, whereas the results achieved when mixtures of activated carbon and Ni/Al 2O3 were employed as catalyst were even worse than those obtained in a conventional oven. Several hypotheses were considered in order to find an explanation for these poor results, the nature of the microplasmas formed during the process being the most likely factor. The high proportions of H2 present in the reactor when the dry reforming of coke oven gas is carried out may give rise to microplasmas of higher temperature than in the dry reforming of CH4. This will cause the Ni particles to sinter significantly, leading to a decrease in the conversions

Microwave-assisted CO2 reforming of coke oven gas: An exception to the general rule?

It has been previously reported that the dry reforming of methane can be enhanced by means of microwave heating. In this article, this technology is applied to the CO2 reforming of coke oven gas (COG). The results obtained were opposite to those reported in the CO2 reforming of CH4, since in the case of the COG, microwave heating only slightly enhanced the conversions when an activated carbon was used as catalyst, whereas the results achieved when mixtures of activated carbon and Ni/Al 2O3 were employed as catalyst were even worse than those obtained in a conventional oven. Several hypotheses were considered in order to find an explanation for these poor results, the nature of the microplasmas formed during the process being the most likely factor. The high proportionsof H2 present in the reactor when the dry reforming of coke oven gas is carried out may give rise to microplasmas of higher temperature than in the dry reforming of CH4. This will cause the Ni particles to sinter significantly, leading to a decrease in the conversions

Microwave Heating Applied to Pyrolysis

the MW pyrolysis as an original thermochemical process of materials is presented. This chapter comprises a general overview of the thermochemical and quantifying aspects of the pyrolysis process, including current application togethe with a compilation of the most frequently used materialsPeer reviewe

An updated suprageneric classification of planktic foraminifera after growing evidence of multiple benthic-planktic transitions

Planktic foraminifera have traditionally been classified within a single order: Globigerinida. However, recent phylogenetic studies, both molecular and stratophenetic, are evidencing the polyphyletic origin of planktic foraminifera from several benthic ancestors. At least four independent events of benthic-planktic transition have been identified. One of them occurred after the Cretaceous–Paleogene boundary mass extinction, originating the first Cenozoic globigerinids. Another three occurred in the Mesozoic, originating three groups of planktic foraminifera (globotruncanids, heterohelicids and guembelitriids) not related phylogenetically to each other or to current globigerinids. These findings make it necessary to carry out an exhaustive review of their suprageneric systematics, mainly at the order level. Here we propose a new, more natural classification, grouping them into four orders: Globigerinida, Heterohelicida, Globotruncanida n. ord., and Guembelitriida n. ord. To better reflect the diversity and phylogeny of planktic foraminifera, we have also defined two new superfamilies: Abathomphaloidea n. superfam. and Parvularugoglobigerinoidea n. superfam., and one new family: Parvularuglobigerinidae n. fam

Propiedades, ventajas e inconvenientes de los materiales utilizados en supercondensadores

Este trabajo recoge una visión general de las propiedades, ventajas e inconvenientes de los principales materiales usados en los electrodos de los condensadores electroquímicos (también denominados supercondensadores). La elección de estos materiales tiene una enorme influencia en las características finales del dispositivo electroquímico. Entre los materiales de electrodo disponibles para su aplicación en supercondensadores se incluyen los materiales porosos basados en carbón, los óxidos de metales de transición y los polímeros conductores. Cada una de estas familias de materiales presenta unas ventajas e inconvenientes, por ello, en numerosas ocasiones no se emplea un único tipo de material para la elaboración de los electrodos, sino que la tendencia va dirigida hacia el uso de electrodos híbridos, es decir, aquellos constituidos por materiales de distinta naturaleza que combinan los aspectos beneficiosos y compensan las limitaciones de cada uno de los materiales por separado

Carbon Xerogels: The Bespoke Nanoporous Carbons

This chapter focuses on the main features of resorcinol-formaldehyde–based carbon xerogels. The first part of the chapter discusses ways of synthesizing these materials and the different variables involved. Then a review of the ways in which the meso- and macroporosity of organic xerogels can be controlled by adjusting the synthesis conditions is undertaken. Special attention is paid to the pH and components of the precursor solution and how these variables are interrelated with each other. The formation of the microporosity during the carbonization or activation processes that give rise to the carbon xerogels is also briefly discussed. Besides the fact that the porosity of these materials can be tailored during the synthesis, another notable characteristic is that, compared with most porous carbons, they possess a relatively high electrical conductivity, which make them ideal materials for use as electrodes in energy storage devices. Their use in supercapacitors and in lithium ion batteries is addressed in the last part of the chapter

Designing Nanostructured Carbon Xerogels

The syntesis of nanostructure carbon xerogels, the properties of carbon gels and the applications of carbon xerogels are reviewedPeer reviewe

Contribution of orbital forcing and Deccan volcanism to global climatic and biotic changes across the Cretaceous-Paleogene boundary at Zumaia, Spain

Untangling the timing of the environmental effects of Deccan volcanism with respect to the Chicxulub impact is instrumental to fully assessing the contributions of both to climate change over the Cretaceous-Paleogene boundary (KPB) interval. Despite recent improvements in radiometric age calibrations, the accuracy of age constraints and correlations is insufficient to resolve the exact mechanisms leading to environmental and climate change in the 1 m.y. across the KPB. We present new high-resolution planktic foraminiferal, geochemical, and geophysical data from the Zumaia section (Spain), calibrated to an updated orbitally tuned age model. We provide a revised chronology for the major carbon isotope excursions (CIEs) and planktic foraminiferal events and test temporal relationships with different models of the eruptive phases of the Deccan Traps. Our data show that the major CIEs near the KPB, i.e., the late Maastrichtian warming event (66.25–66.10 Ma) and the Dan-C2 event (65.8–65.7 Ma), are synchronous with the last and the first 405 k.y. eccentricity maximum of the Maastrichtian and the Danian, respectively, and that the minor Lower C29n event (65.48–65.41 Ma) is well constrained to a short eccentricity maximum. Conversely, we obtained evidence of abrupt environmental change likely related to Deccan volcanism at ca. 65.9 Ma, based on a bloom of opportunistic triserial guembelitriids (Chiloguembelitria). The orbital, isotopic, and paleobiological temporal relationships with Deccan volcanism established here provide new insights into the role of Deccan volcanism in climate and environmental change in the 1 m.y. across the KPB. © 2021. The Authors. Gold Open Access: This paper is published under the terms of the CC-BY license