固体氧化物燃料电池燃料重整技术研究进展

对固体氧化物燃料电池(SOFC)燃料重整技术的研究进展进行了综述。分别对催化裂解、蒸气重整、部分氧化、自供热重整等燃料外部重整技术,以及直接氧化和直接蒸气内部重整等内部重整技术的研究进展进行了评述,对每种重整方式的特点进行了介绍,并展望了其今后的发展趋势。     

碳燃料固体氧化物燃料电池结构研究进展

直接碳燃料固体氧化物燃料电池（direct carbon-fueled solid oxide fuel cells,DC-SOFC）是一种通过电化学过程将碳燃料的化学能直接转化为电能的发电装置,具有优异的发电效率、高的燃料利用率及低的碳排放。然而,相比气体和液体燃料,固体燃料的流动性较低,因此如何提高固体燃料传输速率并有效促进阳极反应动力学过程,以及在工作状态下高效、便捷地添加燃料是目前DC-SOFC要解决的关键问题。本文综述了近年来直接碳固体氧化物燃料电池结构的研究进展,总结了电池宏观结构与阳极微观形貌方面的发展,讨论了碳燃料固体氧化物燃料电池亟待解决的问题及发展方向。     

固体氧化物燃料电池反应器

固体氧化物燃料电池是一种正在发展中的新型发电装置。自80年代以来,已研制出这样的固体氧化物燃料电池。它既能发电,又同时能生产化工产品。本文综述了这方面的研究现状及其进展。     

固体氧化物燃料电池高效利用生物质气前景分析

生物质气具有来源广、总量大的特点,其规模化利用可有效缓解我国未来能源供需紧张的矛盾,但实现规模化利用的前提是开发出适合其分散、热值低、组成变化等特点的利用技术. 本工作分析了我国生物质气的资源情况,阐述了生物质气利用技术的现状与未来发展趋势,并对固体氧化物燃料电池(SOFC)转换生物质气的技术与经济可行性进行了分析. 结果表明,SOFC能够很好地适应生物质气分散、热值低、组成变化的特点,与传统发电方式相比,SOFC发电可望具有更好的经济性. SOFC规模化利用生物质气将可缓解我国未来电力供需紧张矛盾,具有很好的环境及社会效益,发展前景广阔.     

固体氧化物燃料电池系统及其应用

对固体氧化物燃料电池系统和单体电池及其工作原理、材料组成等作了简要介绍,并介绍了固体氧化物燃料电池在电厂混合发电方面与燃气轮机组成的联合系统技术以及以天然气为燃料家庭热电联产方面的应用。并指出固体氧化物燃料电池由于其高效、环保清洁将是未来能源利用的主要方式。     

生物质燃料在水泥厂的应用

<正>生物质燃料具有可再生、洁净、点火容易、CO2近似零排放等优点,可替代化石燃料用于工业行业。近些年来,生物质燃料在欧盟、北美等发达国家发展迅速,有些水泥厂也在使用生物质燃料。近十年来,生物质燃料在我国电力行业得到了逐步应用,但国内水泥厂使用生物质燃料并不多见。为了有别于化石燃料(煤、石油、天然气等),生物质燃料一般是指农林废弃物,如秸秆、锯末、木屑、甘蔗渣、稻壳等。根据生物质燃料是否经过成型加工,     

基于对称双阴极结构固体氧化物燃料电池乙醇燃料内直接重整的电化学性能

对乙醇燃料应用到新型对称双阴极结构固体氧化物燃料电池中直接内重整反应运行进行了探索研究。结果显示,将乙醇以一定的水醇比通入到电池中在输出功率密度为0.137 W/cm2@0.8 V下运行超过100 h依然保持稳定,电池内部发生轻微的积碳现象,表明该新型结构电池可进行碳基燃料直接内重整运行,具有较好的应用前景。     

生物质燃料在水泥工业中的开发与应用

根据我国有关部门的总体规划，2010年和2020年我国可再生能源占能源总消费的比重将分别达到10％和15％。当前国际水泥界正处于热点的生物质燃料开发与应用的课题，值得我们密切关注。     

液态金属阳极固体氧化物燃料电池中的电解质腐蚀

近年来,由于具有极高的理论转化效率,液态金属阳极直接碳固体氧化物燃料电池受到关注;然而,液态金属电极对电解质的腐蚀是降低其性能和限制其寿命的关键因素之一。本文综述了液态金属和氧化物,主要是液态锑(Sb)和氧化锑(Sb₂O₃),对固体氧化物燃料电池常用ZrO₂和CeO₂基电解质的化学和电化学腐蚀研究成果,并讨论了减缓腐蚀程度的途径与可能性。     

固体生物质燃料的工业分析方法对比

文章将固体生物质燃料样品分别按照GB/T 28731-2012《固体生物质燃料工业分析方法》和GB/T 212-2008《煤的工业分析方法》进行对比试验,结果显示两种方法得出的结果接近,无显著性差异,在实际工作中具有一定的指导意义。     

Biodiesel formulations as fuel for internally reforming solid oxide fuel cell

Biodiesel (alkyl ester of rapeseed oil) is prepared using various, methyl, ethyl and butyl alcohols through the transesterification process. Sodium hydroxide and sulfuric acid are used as catalyst for methyl alcohol, ethyl alcohol and butyl alcohol respectively. Biodiesel-water formulations are formulated using water and emulsifiers like sodium lauryl sulphate (SLS) and SPAN 80 in a high shear mixer. The formulations are tested at 800 °C as fuel for internal reforming in solid oxide fuel cells (SOFCs). The formulations based on methyl and butyl esters require the use of emulsifiers to prepare stable emulsions, while ethyl esters are able to form stable emulsions without emulsifiers. The decrease in the biodiesel concentration of formulation does not have any effect on the power density of the ethyl ester formulation. Fuel cells fuelled with 20% formulations lasted longer than 50% formulations in all the formulations tested as result of increase in steam carbon ratio resulting in effective removal of carbon deposited on the anode surface. Butyl ester formulations exhibited the worst performance in both types of formulation tests. The best performance was exhibited by 20% ethyl formulation in terms of life of the cell but 50% methyl ester formulations exhibit the highest power density.     

Modelling of an indirect internal reforming solid oxide fuel cell

Creation of an autothermal system by coupling an endothermic to an exothermic reaction demands the matching of the thermal requirements of the two reactions. The application under study is a solid oxide fuel cell (SOFC) with indirect internal reforming (IIR) of methane, whereby the endothermic steam reforming reaction is thermally coupled to the exothermic oxidation reactions. A steady-state model of an IIR-SOFC has been developed to study the mismatch between the thermal load associated with the rate of steam reforming at typical SOFC temperatures and the local amount of heat available from the fuel cell reactions. Results have shown a local cooling effect, undesirable for ceramic fuel cells, close to the reformer entrance. The system behaviour towards changes in catalyst activity, fuel inlet temperature, current density, and operating pressure has been studied. Increasing the operating pressure is shown to be an effective way of reducing both the local cooling caused by the reforming reactions and the overall temperature increase across the cell. Simulations for both counter-flow and co-flow configurations have been performed and compared.     

Modeling the temperature field in the reforming anode of a button-shaped solid oxide fuel cell

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.     

Thermodynamic analysis for a solid oxide fuel cell with direct internal reforming fueled by ethanol

In the present study, a detailed thermodynamic analysis is carried out to provide useful information for the operation of solid oxide fuel cells (SOFC) with direct internal reforming (DIR) fueled by ethanol. Equilibrium calculations are performed to find the ranges of inlet steam/ethanol (H₂O/EtOH) ratio where carbon formation is thermodynamically unfavorable in the temperature range of 500-1500 K. Two types of fuel cell electrolytes, i.e., oxygen-conducting, and hydrogen-conducting electrolytes, are considered. The key parameters determining the boundary of carbon formation are temperature, type of solid electrolyte and extent of the electrochemical reaction of hydrogen. The minimum H₂O/EtOH ratio for which the carbon formation is thermodynamically unfavored decreases with increasing temperature. The hydrogen-conducting electrolyte is found to be impractical for use, due to the tendency for carbon formation. With a higher extent of the electrochemical reaction of hydrogen, a higher value of the H₂O/EtOH ratio is required for the hydrogen-conducting electrolyte, whereas a smaller value is required for the oxygen-conducting electrolyte. This difference is due mainly to the water formed by the electrochemical reaction at the electrodes.     

Fuel processing in direct propane solid oxide fuel cell and carbon dioxide reforming of propane over Ni-YSZ

This work is aimed at understanding the reaction mechanism of propane internal reforming in the solid oxide fuel cell (SOFC). This mechanism is important for the design and operation of SOFC internal processing of hydrocarbons. An anode-supported SOFC unit with Ni-YSZ anode operating at 800 °C was tested with direct feeding of 5% propane. CO₂ reforming of propane was carried out in a reactor with Ni-YSZ catalyst to simulate internal propane processing in SOFC. The performance of this direct propane SOFC is stable. The C specie formed over the anode functional layer of SOFC can be completely removed. The major gas products of SOFC are H₂, CO, CH₄, C₂H₄ and CO₂. Pseudo-steady-state internal processing of propane in the anode catalytic layer of SOFC is associated with a CO₂/C₃H₈ molar ratio of about 1.26 and basically CO₂ reforming of propane. CO₂ dissociation to produce the O species to oxidize the C species from dehydrogenation and dissociation of propane and its fragments should be the major reaction during CO₂ reforming of propane.     

Reforming methanol to electricity in a high temperature PEM fuel cell

In this paper we demonstrate for the first time a compact power unit, where a methanol reforming catalyst is incorporated into the anode of a PEMFC. The proposed internal reforming methanol fuel cell (IRMFC) mainly comprises: (i) a H₃PO₄-imbibed polymer electrolyte based on aromatic polyethers bearing pyridine units, able to operate at 200 °C and (ii) a 200 °C active and with zero CO emissions Cu–Mn–O methanol reforming catalyst supported on copper foam. Methanol is being reformed inside the anode compartment of the fuel cell at 200 °C producing H₂, which is readily oxidized at the anode to produce electricity. The IRMFC showed promising electrochemical behavior and no signs of performance degradation for more than 72 h.     

平板式直接内重整固体氧化物燃料电池的一维动态建模与仿真

This article aims to investigate the transient behavior of a planar direct internal reforming solid oxide fuel cell (DIR-SOFC) comprehensively. A one-dimensional dynamic model of a planar DIR-SOFC is first developed based on mass and energy balances, and electrochemical principles. Further, a solution strategy is presented to solve the model, and the International Energy Agency (IEA) benchmark test is used to validate the model. Then, through model-based simulations, the steady-state performance of a co-flow planar DIR-SOFC under specified initial operating conditions and its dynamic response to introduced operating parameter disturbances are studied. The dynamic responses of important SOFC variables, such as cell temperature, current density, and cell voltage are all investigated when the SOFC is subjected to the step-changes in various operating parameters including both the load current and the inlet fuel and air flow rates. The results indicate that the rapid dynamics of the current density and the cell voltage are mainly influenced by the gas composition, particularly the H2 molar fraction in anode gas channels, while their slow dynamics are both dominated by the SOLID (including the PEN and interconnects) tem-perature. As the load current increases, the SOLID temperature and the maximum SOLID temperature gradient both increase, and thereby, the cell breakdown is apt to occur because of excessive thermal stresses. Changing the inlet fuel flow rate might lead to the change in the anode gas composition and the consequent change in the current den-sity distribution and cell voltage. The inlet air flow rate has a great impact on the cell temperature distribution along the cell, and thus, is a suitable manipulated variable to control the cell temperature.     

A novel design for solid oxide fuel cell stacks

Conventional fuel cell stack designs suffer from severe spatial non-uniformity in both temperature and current density. Such variations are known to create damaging thermal stresses within the stack and thus, impact overall lifespan. In this work, we propose a novel stack design aimed at reducing spatial variations at the source. We propose a mechanism of distributed fuel feed in which the heat generation profile can be influenced directly. Simulation results are presented to illustrate the potential of the proposed scheme.     

Electrophoretically deposited thin film electrolyte for solid oxide fuel cell

Abstract

Thin films of 8 mol% yttria stabilised zirconia (YSZ) electrolyte have been deposited on non-conducting porous NiO–YSZ anode substrates using electrophoretic deposition (EPD) technique. Deposition of such oxide particulates on non-conducting substrates is made possible by placing a conducting steel plate on the reverse side of the presintered porous substrates. Thickness of the substrates, onto which the deposition has been carried out, varied in the range 0·5–2·0 mm. Dense and uniform YSZ thin films (thickness: 5–20 μm) are obtained after being cofired at 1400°C for 6 h. The thickness of the deposited films is seemed to be increased with increasing porous substrate thickness. Solid oxide fuel cell (SOFC) performance is measured at 800°C using coupon cells with various anode thicknesses. While a peak power density of 1·41 W cm^?2 for the cells with minimum anode thickness of 0·5 mm is achieved, the cell performance decreases with anode thickness.