Gradual Internal Reforming of Ethanol in Solid Oxide Fuel cells

AbstractElectrolyte (yttria-stabilised zirconia, YSZ) supported solid oxide fuel cells (SOFCs) were fabricated using spin coating of standard LSM cathode and Ni-YSZ cermet anode. A ceria-based catalytic layer was deposited onto the anode with a special current collector design. Such a single cell configuration allows operation by gradual internal reforming of direct carbon-containing fuels. First, the fabricated single cells were operated with hydrogen to determine the optimised conditions of fuel concentration and flow rate regarding faradaïc efficiency. Then, the fuel was switched to dry ethanol and the cells were operated for several hours (100h) with good stability. Post-operation electron microcopy analyses revealed no carbon formation in the anode layer. The results indicate that the gradual internal reforming mechanism is effective, opening up the way to multi-fuel SOFCs, provided that a suitable catalyst layer and cell design are available

Effect of Catalyst Layer and Fuel Utilization on the Durability of Direct Methane SOFC

International audienceSolid oxide fuels cells with and without anodic catalytic layer and specific anodic current collectors were developed in order to be fueled by dry methane. Due to the cell architecture integrating a 0.1wt% Ir-CGO catalyst layer onto the anode, platinum, gold and cupper screen-printed meshes were designed and optimized to ensure efficient current collection between the anode surface and the catalyst membrane. Current density and ageing in H2 and in pure dry CH4 respectively were compared to conventional pressed grid collecting systems. Similar performances were achieved using bulk grids or gold, platinum and copper screen-printed meshes. Operation in pure dry methane is compared with and without the catalytic layer as a function of the fuel utilization. It is demonstrated that long term operation is possible provided that sufficient faradic efficiency is achieved

Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

Background: In an era of shifting global agendas and expanded emphasis on non-communicable diseases and injuries along with communicable diseases, sound evidence on trends by cause at the national level is essential. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic scientific assessment of published, publicly available, and contributed data on incidence, prevalence, and mortality for a mutually exclusive and collectively exhaustive list of diseases and injuries. Methods: GBD estimates incidence, prevalence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) due to 369 diseases and injuries, for two sexes, and for 204 countries and territories. Input data were extracted from censuses, household surveys, civil registration and vital statistics, disease registries, health service use, air pollution monitors, satellite imaging, disease notifications, and other sources. Cause-specific death rates and cause fractions were calculated using the Cause of Death Ensemble model and spatiotemporal Gaussian process regression. Cause-specific deaths were adjusted to match the total all-cause deaths calculated as part of the GBD population, fertility, and mortality estimates. Deaths were multiplied by standard life expectancy at each age to calculate YLLs. A Bayesian meta-regression modelling tool, DisMod-MR 2.1, was used to ensure consistency between incidence, prevalence, remission, excess mortality, and cause-specific mortality for most causes. Prevalence estimates were multiplied by disability weights for mutually exclusive sequelae of diseases and injuries to calculate YLDs. We considered results in the context of the Socio-demographic Index (SDI), a composite indicator of income per capita, years of schooling, and fertility rate in females younger than 25 years. Uncertainty intervals (UIs) were generated for every metric using the 25th and 975th ordered 1000 draw values of the posterior distribution. Findings: Global health has steadily improved over the past 30 years as measured by age-standardised DALY rates. After taking into account population growth and ageing, the absolute number of DALYs has remained stable. Since 2010, the pace of decline in global age-standardised DALY rates has accelerated in age groups younger than 50 years compared with the 1990–2010 time period, with the greatest annualised rate of decline occurring in the 0–9-year age group. Six infectious diseases were among the top ten causes of DALYs in children younger than 10 years in 2019: lower respiratory infections (ranked second), diarrhoeal diseases (third), malaria (fifth), meningitis (sixth), whooping cough (ninth), and sexually transmitted infections (which, in this age group, is fully accounted for by congenital syphilis; ranked tenth). In adolescents aged 10–24 years, three injury causes were among the top causes of DALYs: road injuries (ranked first), self-harm (third), and interpersonal violence (fifth). Five of the causes that were in the top ten for ages 10–24 years were also in the top ten in the 25–49-year age group: road injuries (ranked first), HIV/AIDS (second), low back pain (fourth), headache disorders (fifth), and depressive disorders (sixth). In 2019, ischaemic heart disease and stroke were the top-ranked causes of DALYs in both the 50–74-year and 75-years-and-older age groups. Since 1990, there has been a marked shift towards a greater proportion of burden due to YLDs from non-communicable diseases and injuries. In 2019, there were 11 countries where non-communicable disease and injury YLDs constituted more than half of all disease burden. Decreases in age-standardised DALY rates have accelerated over the past decade in countries at the lower end of the SDI range, while improvements have started to stagnate or even reverse in countries with higher SDI. Interpretation: As disability becomes an increasingly large component of disease burden and a larger component of health expenditure, greater research and developm nt investment is needed to identify new, more effective intervention strategies. With a rapidly ageing global population, the demands on health services to deal with disabling outcomes, which increase with age, will require policy makers to anticipate these changes. The mix of universal and more geographically specific influences on health reinforces the need for regular reporting on population health in detail and by underlying cause to help decision makers to identify success stories of disease control to emulate, as well as opportunities to improve. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens

Severe Poverty as a Systemic Human Rights Violation

In the gradual internal reforming (GIR) process, the water released by the electrochemical oxidation of hydrogen at the anode is used for the steam reforming of the fuel in the catalytic layer deposited over the anode of the SOFC. We have developed a highly active ceria-based catalytic layer that efficiently converts the primary fuel (ethanol or methane) into hydrogen using the electrochemically-generated steam. Ir/CGO catalyst was pretreated at 1173 K in He flow with less than 0.5 ppm O2 prior to catalytic testing. The catalyst consists of Ir nanoparticles (mean size of 4 nm in diameter) supported on the surface of sub-micron gadolinia-doped ceria particles and forms a continuous porous layer (~25 μm thick) over the Ni-based anode. An anode-supported solid oxide fuel cell (SOFC) was continuously operated for more than 300 hours with direct methane or (anhydrous) ethanol, with a high current density. The catalytic layer associated with the GIR process avoids the carbon deposition on the anode material surface. Such results represent a significant advance towards the development of fuel-flexible SOFC operating with methane or ethanol

MODELLING OF GRADUAL INTERNAL REFORMING PROCESS OVER NI-YSZ SOFC ANODE WITH A CATALYTIC LAYER

SSCI-VIDE+ATARI+KGR:PGEInternational audienceMethane appears to be a fuel of great interest for solid oxide fuel cell (SOFC) systems because it can be directly converted into hydrogen by Internal Reforming within the SOFC anode. To cope with carbon formation, a new SOFC cell configuration combining a catalyst layer with a classical anode was developed. The rate of the CH4 consumption in the catalyst layer (Ir-CGO) was determined experimentally for small values of steam to carbon ratios. This paper proposes a modelling and a simulation, using the CFD-Ace software package, of the behaviour of a SOFC operated in Gradual Internal Reforming (GIR) conditions. This model of SOFC takes into account the kinetics of the steam reforming reaction in the catalyst layer in order to assess the influence of the steam to carbon ratio and the cell polarization. Because the risk of carbon formation is greater under GIR operation, a detailed thermodynamic analysis was carried out. Thermodynamic equilibrium calculations allowed us to predict the conditions of carbon formation occurrence

Gradual Internal Reforming of pure methane in SOFC : from model to operation

International audienc

Durable direct ethanol anode-supported solid oxide fuel cell

Anode-supported solid oxide fuel cells accumulating more than 700 h of stable operation on dry ethanol with high current output are reported. A highly active ceria-based catalytic layer deposited onto the anode efficiently converts the primary fuel into hydrogen using the electrochemically generated steam. On the other hand, standard fuel cells without the catalytic layer collapse because of carbon deposit formation within the initial 5 h of operation with ethanol. The nanostructured ceria-based catalyst forms a continuous porous layer (∼25 µm thick) over the Ni-based anode support that has no apparent influence on the fuel cell operation and prevents carbon deposit formation. Moreover, the catalytic layer promotes overall steam reforming reactions of ethanol that result in similar current outputs in both hydrogen and ethanol fuels. The stability of single cells, with relatively large active area (8 cm2), confirms the feasibility of a catalytic layer for internal reforming of biofuels in solid oxide fuel cells. The experimental results provide a significant step towards the practical application of direct ethanol solid oxide fuel cells

The influence of catalyst deposition onto dense membranes on catalytic properties

SSCI-VIDE+ATARI+KIC:PGEInternational audienceHigh temperature Solid Oxide Fuel Cells (SOFC) are promising energy conversion systems that can be operated directly on hydrocarbons (fossil or renewable sources) by using Ni-based anodes. In general, the hydrocarbon is mixed with steam, oxygen or carbon dioxide before feeding to the SOFC so that internal steam reforming, partial oxidation or dry reforming, respectively, could happen at the anode without carbon deposition. However, the endothermic nature of reforming reaction could induce thermal gradient and mechanical stress that dramatically lowers the lifetime of the SOFC.The system could be improved by operation with dry CH4. This could be realised by depositing a catalytic layer of Ir/CGO on conventional Ni cermet anode as shown in Fig. 11-4. SOFC provides water for steam reforming of CH4 on the Ir/CGO layer by Gradual Interna Reforming, while H2 produced from steam reforming is in turn used to operate the SOFC. Both reactions are self-sustained. In order to optimize the performance, it is necessary to better understand the catalytic behavior under real operating conditions, i.e., the influence of O2- transport from the cathode. In particular, the fundamentals of heterogeneous catalysis under polarization are to be fully understood. The present work shows that the membrane itself may influence, depending on its chemical nature, the reforming activity of the Ir/CGO catalyst

A Fuel-Flexible Solid Oxide Fuel Cell Operating in Gradual Internal Reforming

ENERGIE+PGEAn electrolyte supported solid oxide fuel cell (SOFC) was continuously operated with hydrogen, methane, and bioethanol for nearly 400 hours without adding water, O-2, or CO2, and delivering a rather stable power output. Such a fuel-flexible SOFC was achieved by using both an anodic catalytic layer, which efficiently converts the primary fuel into hydrogen, and by the operation in gradual internal reforming conditions, which prevented degradation due to carbon formation. (C) 2014 The Electrochemical Society. All rights reserved

Design of anodic architectures for direct methane SOFC

SSCI-VIDE+ATARI+PGEInternational audienceNon