Temperature and Impurity Concentration Effects on Degradation of Nickel/Yttria‐stabilised Zirconia Anode in PH<sub>3</sub>‐Containing Coal Syngas

Zhi, Mingjia; Cayan, Fatma N.; Gemmen, Randall; Pakalapati, Suryanarayana R.; Wu, Nianqiang

doi:10.1002/fuce.200900016

Cited by 11 publications

(9 citation statements)

References 24 publications

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“…But the precipitate phase cannot be identified in this study. In the Ni/YSZ anode SOFCs, the PH 3 can react with Ni in the all cells in previous works [19,20,[104][105][106][107]. In this study, similar morphology changes were observed.…”

Section: Effect Of Ph 3 On Ni In Anode Of Sofcssupporting

confidence: 84%

“…So it is essential to examine the effect of the contaminant on the SOFCs performance in terms of structure and chemistry changes. PH 3 is an interesting contaminant, which was investigated by different research groups in Ni/YSZ anode SOFCs [19,20,[104][105][106][107] or other anode SOFCs [108,109]. In the Ni/YSZ anode SOFCs, the PH 3 can react with Ni in the all cells in those previous works.…”

Section: Introductionmentioning

confidence: 99%

“…However, different works showed different products with various operation conditions. Even with the syngas as the fuel gas, the PH 3 can react with Ni to form phosphate [19,105] or phosphide [20,107] as the dominate product in different papers. In those previous works, the The cells were each cross-sectioned and submitted to examination by using SEM and TEM.…”

Section: Introductionmentioning

confidence: 99%

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Nanostructure and Chemistry Evolution of Solid Oxide Fuel Cells upon Cell Operation

Chen¹

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Nanostructure and Chemistry Evolution of Solid Oxide Fuel Cells upon Cell Operation By Song Chen Solid Oxide Fuel Cells (SOFCs) are clean and efficient alternatives to conventional power generation technology. In SOFC, electrochemical reactions take place on the triple-phase boundaries (TPBs) between the electrolyte, the electrode and the gaseous fuel. Small changes in TPB structure or chemistry, and the interface between electrode and electrolyte can drastically affect SOFC performance and lifetime. However, very limited experimental work has been reported on the nanostructure and chemistry evolution of interface and TPBs in the SOFC upon cell operation. The main goal of this dissertation is to investigate the nanostructure and chemistry of the grain boundaries and interfaces including TPB in SOFC, and their evolution with respect to the cell operation, and the variation of the fuel chemistry. The nanostructure and chemistry of the SOFC was investigated using Transmission Electron Microscopy. The analysis of microstructural and chemical evolution of anode was focused on the grain boundaries and TPB junctions of Ni/YSZ anode, in the two different aspects detailed in the following. (1). Comparisons were made between an as-received cell and a cell operated at 800°C for several hundred hours using H 2 and syngas as fuel. Significant crystallographic evolution, including the formation of previously un-acknowledged NiO interface ribbon phase and the Y migration along the Ni/YSZ interface, was studied systematically. (2). The interaction of trace (ppm) phosphine with Ni-YSZ anode of commercial SOFC has also been investigated and evaluated for both synthesis gas and hydrogen fuels in an effort to examine the reactions between phosphine and YSZ. A principal benefit of SOFC is that it can utilize diverse fuels, including those derived from fossil and biotic sources. At elevated temperatures, SOFCs demonstrate some tolerance to fuel impurities that poison most other fuel cell systems. However, for coal-derived synthesis gas (syngas) under typical SOFC operating conditions, some trace material species may escape gas cleanup processing to impact the SOFC anode performance and long term stability. Among such trace species, phosphorus is of particular interest because the nickel anode is known to rapidly react with volatile phosphorus compounds to form a series of nickel phosphide products, which results in severe depletion of the nickel component and degradation of the anode. The particular focus of the present study is to analyze the interaction of P with YSZ, so as to elucidate the complete set of cell degradation modes induced by phosphine. In this study, a new YPO 4 phase was observed at YSZ/Ni/YSZ triple phase junctions, which indicates the reaction between PH 3 and YSZ in SOFCs. In addition to the work on the anode, the microstructure and chemistry evolution of the cathode upon cell operation is studied as well. The focus is on the infiltration of cathode which has been proved to be effective in enhancing the cathode pe...

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Section: Effect Of Ph 3 On Ni In Anode Of Sofcssupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nanostructure and Chemistry Evolution of Solid Oxide Fuel Cells upon Cell Operation

Chen¹

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“…As little as 0.5 ppmv of phosphorous species in syngas can result in a degradation of SOFC power density . Phosphorous‐containing species segregates at grain boundaries in the anode as nickel phosphide/phosphate and zirconia phosphate, which reduces the electronic conductivity of the anode and inhibits the YSZ network for oxygen ion transport . High steam levels are thought to resist anode poisoning by phosphorous …”

Section: Emissions and Abatementmentioning

confidence: 99%

Alkali, boron and phosphorous removal from coal‐derived syngas: review and thermodynamic considerations

Dolan

Ilyushechkin

McLennan

et al. 2011

Asia-Pacific J Chem Eng

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Alkalis are highly corrosive towards materials associated with syngas processing and utilisation, including ceramic particulate filters and metallic components. The removal of alkali species, consequently, is an important step in the cleaning of coal and biomass-derived syngas. The origins of the alkali contaminant govern the ability of specific sorbents to remove these species via chemical means. Alkali salt removal is dependent on the formation of an acid halide species, a reaction, which in the absence of H 2 O, involves hydrogen and carbon dioxide. This reaction becomes increasingly unfavourable above 1000 C, but below this temperature, equilibrium conversion approaches 100%. The fluxing of a gasifier slag, which is often necessary to reduce viscosity to a level that allows tapping, reduces its ability to absorb alkali halides. This effect however was not observed with oxide-based alkalis, which shows strong affinity for gasifier slag regardless of fluxing, up to 1600 C. Furthermore, there is a potential for removal of boron and phosphorous contaminants using these same sorbents. In a complete high-temperature, dry gas cleaning sequence, alkali removal would ideally be undertaken prior (or simultaneously to) halide removal and prior to sulfur removal.

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“…PH 3 and P x O y have been chosen for P related effects study [30][31][32][33][34][35][36][37][38][39][40][41]. It is been believed that PH 3 might be the main specie in coal syngas, though some gas phase equilibrium calculations showed PH 3 would be oxidized in P x O y form because of the high steam concentration [32].…”

Section: Phosphorus (P)mentioning

confidence: 99%

Electrochemical and Microstructural Analysis of Solid Oxide Fuel Cell Electrodes

Zhi¹

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Electrochemical and Microstructural Analysis of Solid Oxide Fuel Cell Electrodes Mingjia Zhi Fuel cells offer several advantages over conventional routines of power generation, such as substantially higher conversion efficiency, modular construction, minimal sitting restriction, and much lower production of pollutants. Solid oxide fuel cell (SOFC), in principle, can utilize all kinds of combustion fuels including coal derived syngas (CSG). The U.S. Department of Energy is currently working on coupling coal gasification and SOFC to form Integrated Gasification Fuel Cell (IGFC) systems. Such IGFC systems will enable the clean, efficient and cost-effective use of coal-the nation's most abundant fossil fuel. However several issues need to be considered before SOFC can be really commercialized. The anode of SOFC can interact with the trace impurities in CSG such as arsenic, phosphorous, chlorine etc, which leads severe degradation of the cell performance. The operation temperature of current SOFC is also high (>800 o C), which increases the system cost. Hence, further study of both the anode and cathode is necessary in order to develop high performance, long serving time SOFC for IGFC power plant. One of the aims of this project is to investigate the degradation mechanisms of the Ni-YSZ (yttria stabilized zirconia) anode in PH 3 contained coal syngas. Materials microstructure change and electrochemical performance degradation were studied synchronously.

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Temperature and Impurity Concentration Effects on Degradation of Nickel/Yttria‐stabilised Zirconia Anode in PH₃‐Containing Coal Syngas

Cited by 11 publications

References 24 publications

Nanostructure and Chemistry Evolution of Solid Oxide Fuel Cells upon Cell Operation

Nanostructure and Chemistry Evolution of Solid Oxide Fuel Cells upon Cell Operation

Alkali, boron and phosphorous removal from coal‐derived syngas: review and thermodynamic considerations

Electrochemical and Microstructural Analysis of Solid Oxide Fuel Cell Electrodes

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Temperature and Impurity Concentration Effects on Degradation of Nickel/Yttria‐stabilised Zirconia Anode in PH3‐Containing Coal Syngas

Cited by 11 publications

References 24 publications

Nanostructure and Chemistry Evolution of Solid Oxide Fuel Cells upon Cell Operation

Nanostructure and Chemistry Evolution of Solid Oxide Fuel Cells upon Cell Operation

Alkali, boron and phosphorous removal from coal‐derived syngas: review and thermodynamic considerations

Electrochemical and Microstructural Analysis of Solid Oxide Fuel Cell Electrodes

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Temperature and Impurity Concentration Effects on Degradation of Nickel/Yttria‐stabilised Zirconia Anode in PH₃‐Containing Coal Syngas