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Direct-methane solid oxide fuel cells were used to produce electricity and syngas. During initial operation at 750 °C, the
cells produced 0.9 W/cm2 and ≈90% methane conversion to syngas at a rate of 30 sccm/cm2. However, the methane conversion decreased continuously over the first 30–40 h of operation, even though the solid oxide
fuel cells (SOFC) electrical performance was stable. An additional catalyst layer on the anode yielded more stable methane
conversion to syngas. 相似文献
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固体氧化物燃料电池是一种典型的电化学装置,可以把燃料气和空气(或氧气)的化学能直接转化为电能。电池的整个反应过程可以根据还原剂和氧化剂反应自由焓来进行热力学计算。对于最简单的氢气和氧气的反应来说,可以根据可逆反应平衡方程式计算电池的可逆功,而且SOFC系统和外部环境的热交换也是可逆的。SOFC作为一种伴生热能的发电装置,对热力学的理解必不可少。所以本文将首先介绍一下SOFC的热力学基础,而作为一种电化学发电装置,需要系统了解SOFC的电化学基础,其中重点介绍SOFC的电化学分析曲线——i-V曲线。 相似文献
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CeO2‐Ni/YSZ anodes for methane direct oxidation were prepared by the vacuum mix‐impregnation method. By this method, NiO and CeO2 are obtained from nitrate decomposition and high temperature sintering is avoided, which is different from the preparation of conventional Ni‐yttria‐stabilised zirconia(YSZ) anodes. Impregnating CeO2 into the anode can improve the cell performance, especially, when CH4 is used as fuel. The investigation indicated that CeO2‐Ni/YSZ anodes calcined at higher temperature exhibited better stability than those calcined at lower temperature. Under the testing temperature of 1,073 K, the anode calcined at 1,073 K exhibited the best performance. The maximum power density of a cell with a 10 wt.‐%CeO2‐25 wt.‐%Ni anode calcined at 1,073 K reached 480 mW cm–2 after running on CH4 for 5 h. At the same time, high discharge current favoured cell operation on CH4 when using these anodes. No obvious carbon was found on the CeO2‐Ni anode after testing in CH4 as revealed from SEM and corresponding linear EDS analysis. In addition, cell performance decreased at the beginning of discharge testing which was attributed to the anode microstructure change observed with SEM. 相似文献
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Rose Marie Mendoza Joy Marie Mora Rinlee Butch Cervera Po-Ya Abel Chuang 《化学工程与技术》2020,43(12):2350-2358
A 1-D electrochemical model for a solid oxide electrolysis cell (SOEC) is developed and validated using published experimental data. The model combines thermodynamics, kinetic, ohmic, and concentration overpotentials to predict cell performance. For the anode-supported SOEC, good agreement is obtained between the model and experimental data, with ohmic loss being the major contributor to the cell's total overpotential. Both kinetic and concentration losses are less significant due to high-temperature operation. Due to the dominating performance loss, reducing the anode thickness is effective in diminishing the cell potential. Overall, this simple 1-D model can be employed as a design tool to evaluate component design and estimate system performance for industrial applications. 相似文献
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A novel plasma-matrix reformer (PMR) was suggested for methane conversion into hydrogen-rich fuel. To demonstrate the possibility of reforming performance, characteristics of product gas and CH4 conversion were identified according to O2/C ratio, water vapor supply, reformed gas recirculation, and water feed in the recirculation gas affecting energy conversion and hydrogen production. When the reformed gas recirculation and water feed to the recirculation pipe were performed at the same time, hydrogen production and energy conversion efficiency were superior compared to the conventional reforming method. The optimal operating conditions of the PMR were determined. The obtained high energy conversion efficiency and hydrogen selectivity indicated the applicability to solid oxide fuel cell stacks for residential power generation. 相似文献
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abstract Thermodynamic analyses in the literature have shown that solid oxide fuel cells (SOFCs) with proton conducting electrolyte (H-SOFC) exhibited higher performance than SOFC with oxygen ion condu... 相似文献
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Solid oxide fuel cells (SOFCs) have the potential to meet the critical energy needs of our modern civilization and minimize the adverse environmental impacts from excessive energy consumption. They are highly efficient, clean, and can run on variety of fuel gases. However, little investigative focus has been put on optimal power output based on electrode microstructure. In this work, a complete electrode polarization model of SOFCs has been developed and utilized to analyze the performance of functionally graded anode with different particle size and porosity profiles. The model helps to understand the implications of varying the electrode microstructure from the polarization standpoint. The work identified conditions when grading can improve the cell performance and showed that grading is not always beneficial or necessary. 相似文献
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Thin Yttrium-Stabilized Zirconia Electrolyte Solid Oxide Fuel Cells by Centrifugal Casting 总被引:4,自引:0,他引:4
A centrifugal casting technique was developed for depositing thin 8-mol%-yttrium-stabilized zirconia (YSZ) electrolyte layers on porous NiO-YSZ anode substrates. After the bilayers were cosintered at 1400°C, dense pinhole-free YSZ coatings with thicknesses of ∼25 μm were obtained, while the Ni-YSZ retained porosity. After La0.6 Sr0.4 Co0.2 Fe0.8 O3 (LSCF)-Ce0.9 Gd0.1 O1.95 (GDC) or La0.8 Sr0.2 MnO3 (LSM)-YSZ cathodes were deposited, single SOFCs produced near-theoretical open-circuit voltages and power densities of ∼1 W/cm2 at 800°C. Impedance spectra measured during cell tests showed that polarization resistances accounted for ∼70%–80% of the total cell resistance. 相似文献
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A finite‐volume based mathematical model has been developed for modeling hydrogen production by a tubular cell of solid oxide steam electrolyzer (SOSE), taking into account the electrochemical reactions and heat/mass transfer effects. The model is composed of three systems of nonlinear equations that govern the electric current density, energy balance in the solid SOSE cell, and energy balance in the flow of steam and hydrogen. The simulated hydrogen production rate proportional to the applied potential agreed well with the experimental measurements published in the literature. The intermediate modeling results indicated that the activation effect dominate the overall cell overpotential due to low exchange current density through the SOSE cell electrodes. Thus, higher electrode activity was identified as an important factor for enhancing cell performance. Parametric modeling analyses were conducted to gain better understanding of the SOSE characteristics. It was found that low‐temperature gas intake would cause a high temperature gradient in the tubular cell material at the inlet, possibly leading to a thermal expansion problem. The risk could be reduced by increasing the gas inlet temperature. It was also found that energy‐efficient SOSE hydrogen production can be achieved by reducing the hydrogen content in the steam intake and regulating the steam intake flow rate to an optimum that minimizes the overall electrical and thermal requirements. More parametric modeling results are discussed in this paper. The tubular SOSE cell model developed in this study can easily be expanded to accomplish tubular SOSE stack analysis for comprehensive system design optimization. 相似文献
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A model predicting the temperature field in the porous reforming anode of a solid oxide fuel cell is presented herein. The model is based on mass, momentum, and heat balances of a chemically reacting mixture of gases within the porous matrix of the anode. The important novel characteristic of the model is the consideration of the both internal reforming and electrochemical reactions in the bulk of the porous anode. The electronic and ionic currents in the anodes are calculated utilizing the solution of the Poisson equations for the electric potentials in the porous medium. The transfer current density is described by the Butler–Volmer equation.The model is applied to investigate the temperature field and the reactive flow in button-shaped fuel cells with uniform and graded (multi-layer) anodes composed of Ni and YSZ particles with methane/water vapor mixture used as the fuel. The maximum temperature difference between the hot and cold spots of the anodes is found to reach up to 200 K. The results indicate that the generation of Joule heating caused by the current passing through the anode and the activation losses are the dominating heat sources compared to the gas-water shift and electrochemical reactions. 相似文献
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The effects of anode support fabrication parameters on the cell performance and the redox behavior of the cell are investigated experimentally and theoretically. In the experimental program, an yttria stabilized zirconia based anode supported membrane electrode group (MEG) is developed via the tape casting, co‐sintering and screen printing methodologies. For comparison, various anode supported cells with different electrolyte thickness and anode support porosities are also fabricated. In the theoretical study, a mathematical model is developed to represent the fluid flow, the heat transfer, the species transport and the electrochemical reaction in solid oxide fuel cells. In addition, a redox model representing the mechanical damage in the electrochemical reaction zones due to redox cycling is developed by defining a damage function as a function of strain and a damage coefficient. The effects of anode support porosity and the electrolyte thickness on the cell performance and redox stability of the cells are numerically investigated. The experimental results are compared with the numerical results to validate the mathematical model. Finally, a predictive tool, which is valid for the ranges of the cell fabrication parameters investigated, is developed to estimate the electrochemical performance after single redox cycle. 相似文献
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Solid oxide fuel cells (SOFCs) have several advantages over other types of fuels cells such as high-energy efficiency and
excellent fuel flexibility. To be economically competitive, however, new materials with extraordinary transport and catalytic
properties must be developed to dramatically improve the performance while reducing the cost. This article reviews recent
advancements in understanding oxygen reduction on various cathode materials using phenomenological and quantum chemical approaches
in order to develop novel cathode materials with high catalytic activity toward oxygen reduction. We summarize a variety of
results relevant to understanding the interactions between O2 and cathode materials at the molecular level as predicted using quantum-chemical calculations and probed using in situ surface
vibrational spectroscopy. It is hoped that this in-depth understanding may provide useful insights into the design of novel
cathode materials for a new generation of SOFCs. 相似文献
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介绍了不同形状和类型的固体氧化物燃料电池的各结构部件的常用制备工艺方法,包括:用于平板式支撑体制备的干压法和流延成型法,制备平板膜的涂刷、丝网印刷、离心沉积和旋涂法,管式支撑体制备的注浆成型、挤出成型、热压注、浸涂、凝胶铸模和相转换法,以及用于管式膜制备的涂刷、浸涂、料浆喷涂、电化学气相沉积和热喷涂法。针对每种工艺方法,介绍了其原理和基本工艺操作流程及其在固体氧化物燃料电池制备中的应用,讨论了工艺影响因素。 相似文献
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Fabrication of Dense Zirconia Electrolyte Films for Tubular Solid Oxide Fuel Cells by Electrophoretic Deposition 总被引:3,自引:0,他引:3
Rajendra N. Basu Clive A. Randall Merrilea J. Mayo 《Journal of the American Ceramic Society》2001,84(1):33-40
Electrophoretic deposition (EPD) is used to produce zirconia electrolyte films for tubular solid oxide fuel cells. A simple suspension chemistry (8-mol%-yttria-stabilized zirconia particles in acetic acid) yields films of similar quality to those from conventional approaches (such as electrochemical vapor deposition), but at potentially much less expense. A key factor in obtaining high-density, adherent films via the EPD approach is the application of a thin fugitive phase (carbon in this study) on the porous, doped lanthanum manganite cathode tubes prior to zirconia deposition. 相似文献
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Kefeng Liu Fei Meng Di Zhu Zi Wang Shujie Lou Jing Zhao Haicheng Xiao Yongchun Tang 《化学工程与技术》2020,43(10):2007-2014
A novel Fe-Al/SiO2 catalyst for direct non-oxidative conversion of methane to ethylene, benzene, and naphthalene was synthesized. An Fe-Al/SiO2 catalyst integrated solid oxide electrolysis cell (SOEC) membrane reactor design is further developed. It could be successfully demonstrated that the SOEC enabled the in situ removal of H2, which helps to shift the chemical equilibrium of the methane conversion reaction to enhance the conversion efficiency. 相似文献