1,720,967 research outputs found
Characterization of a 100 W SOFC stack fed by carbon monoxide rich fuels
No full textThis paper presents the evaluation of the performance of a 100 W Solid Oxide Fuel Cell (SOFC) stack with CO rich fuels as anode gas. The study aims at measuring the Open Circuit Voltage (OCV) and the Area Specific Resistance (ASR) when the amount of CO in the anode flow varies from 0 to 40% in volume. At the same time, the FCTestQA procedures were applied and evaluated as methodology for Solid Oxide Fuel Cell testing. The theoretical OCV was measured considering both H2 and CO oxidation and the water gas shift reaction. The OCV values, as a function of CO concentration, resulted closely related to theoretical ones and the ASR value, calculated for different mixtures of fuel, did not change with anode gas composition and it seemed to be a function of the temperature and the degradation of the materials only
Dimethyl sulfide adsorption from natural gas for solid oxide fuel cell applications
No full textThe use of solid oxide fuel cell (SOFC) systems in micro-CHP applications is of great interest because of high efficiency, low emissions and absence of noise. However, SOFCs are sensitive to degradation caused by organic sulfur compounds present in natural gas or added as odorants. Among them, dimethyl sulfide (DMS) is one of the sulfur species most resistant to purification treatments and, relative to DMS removal, a lack in literature is highlighted for the investigated application.
Regarding adsorption technology, the present work deals with an organic sensitivity performance analysis of different commercial sorbents. Virgin and impregnated activated carbons and a natural zeolite were tested, varying gas hourly space velocity, reactor geometry and filter assembly. Because of differences in activity towards DMS exhibited by the investigated materials, to exploit their selectivity, also layered sorbents were realized and tested.
Starting from resulting data, for the yearly operation of 1 kWel SOFC-based micro-CHP system, an optimization of filter assembly (also considering multi-layered configurations) and operative conditions was performed, leading to a strong reduction in filter volume (up to five times) and cost (more than three times), with overall pressure drops compatible with pipeline gas distribution pressure
Experimental Comparison and Performance Evaluation of Planar Solid Oxide Single Cell
No full textNowadays, in a world characterized by the need to reduce the production of pollutants, by global climate changes, by the progressive lack of availability of cheap fossil fuels, one of the most important goals of scientific research is to design systems that can provide energy with low environmental impact. Planar Solid Oxide Fuel Cells (SOFC) are considered to be power generators with high efficiency independent on size and low emissions. Fuel cell laboratory (FCLab) of University of Perugia has focused his studies on SOFC operating at high temperature (800–1000°C), characterized by greater flexibility in the choice of fuel. This study focuses on definition and realization of experimental test able to define the quality of a SOFC single cell and on the effect of test condition parameter. The performance of the cell is evaluated via polarization curves realized in different external conditions. Area Specific Resistance (ASR) is used as main test output. Results analysis confirm that ASR gives important information on fuel cell performance and can be used to compare an qualify SOFC single cell
SOFC operating with ammonia: Stack test and system analysis
No full textAmmonia has been studied as a potential energy vector and suitable fuel for Solid Oxide Fuel Cells (SOFCs). The use of ammonia could guarantee high electrical efficiency, with a carbon free and high energy density fuel. This study analyzes the potential of a power generation system based on a SOFC fueled by NH3. Experimental tests on a SOFC short stack were developed using both pure and diluted ammonia. The tests demonstrated the operation of the concept and highlighted possible advantages in terms of thermal equilibrium. Decomposition of ammonia introduces an endothermic reaction that permits heat absorbance in the anode and a better control of stack temperature. Based on tests results, a thermodynamic model of a complete system was designed and studied. The results demonstrate that the ammonia fueled SOFC is more efficient than an equivalent hydrogen fueled one, due to the cooling effect of internal reactions that reduces ancillaries energy consumptions related to cathode air flow
Adsorption of H2S on residual biomass gasification char
No full textChar is the solid by-product of biomass gasification. Plant owners usually dispose of it at a cost, but its high carbon content and surface area could make it suitable for further applications. In this work, we studied its potential to adsorb hydrogen sulphide (H2S), a common pollutant, e.g. present in the producer gas of gasification, as well as in biogas from anaerobic digestion. We tested different samples of char collected from commercial gasification plants in South Tyrol (Italy). The adsorption was reproduced in a lab-scale fixed bed reactor. The results highlights that all samples could capture hydrogen sulphide, showing different adsorption performance. The surface area of the char and the ash amount seem to affect the removal capacity, although other properties of the materials are probably important. The inlet concentration of hydrogen sulphide does not influence the adsorption capacity significantly
Performance characterization of a novel sorbent for anaerobic gas desulfurization finalized to high temperature fuel cell applications
No full textThe study proposes an innovative CHP system based on the coupling of carbon dioxide dry reforming (CDR) and solid oxide fuel cell (SOFC) technology. To supply CO2 at the CDR unit, increasing at the same time the overall utilization factor, SOFC anode off-gases are recycled for fuel reforming. In the CDR unit, in fact, the CO2 produced at the anodic exhausts reacts with feeding low carbon fuels (in this case natural gas) producing hydrogen and carbon monoxide for the SOFC feeding, thus allowing an internal CO2 reuse. In particular, the SOFC, characterized by high operating temperatures and significant recoverable heat, guarantees suitable temperature of the CDR process, highly endothermic. Moreover, compared to traditional CDR applications, lower temperatures are acceptable because SOFC tolerates feeding gas containing limited amounts of CO and CH4. According to this concept, the SOFC stack can be conveniently fed by a dry reformer reactor. The present study addresses the experimental characterization of SOFC short-stacks performance, in terms of produced power and thermal behavior, when fed by different fuel mixtures produced through dry reforming
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