Internal Partial Oxidation Research Articles

Demonstration of SOFC Power Sources for Drones (UAVs; Unmanned Aerial Vehicles)

Improvement of performance and durability was investigated during liquefied petroleum gas (LPG) utilization for solid oxide fuel cells (SOFCs). Infiltration of La-doped ceria (LDC) into Ni-yttria-stabilized zirconia (Ni-YSZ) anode enhanced the performance compared to Ni-Gd-doped ceria (Ni-GDC) anode due to no formation of zirconia-ceria solid solution between the electrolyte and anode. Internal partial oxidation reforming performed stable power generation without carbon deposition on the anode for 100 h in the condition at 650 oC and O/C ≥ 1.5 according to thermodynamic equilibrium. We successfully demonstrated SOFC power sources using commercially available LPG cartridges for drones (UAVs; unmanned aerial vehicles).

Internal Partial Oxidation Reforming of Butane and Steam Reforming of Ethanol for Anode‐supported Microtubular Solid Oxide Fuel Cells

AbstractInternal partial oxidation reforming of butane and steam reforming of ethanol were investigated using microtubular solid oxide fuel cells (SOFCs) supported on nickel‐gadolinia doped ceria (Ni‐GDC) anodes for portable power sources in emergency situations and for mobilities, such as vehicles, robots and drones. At an oxygen/carbon (O/C) ratio of 1.0, which is a coking condition in the equilibrium, the Ni‐GDC anode deteriorated for 28 h by internal partial oxidation of butane at 650 °C. However, power generation was also impossible after 8 h and 79 h at steam/carbon (S/C) = 1.0 and 1.5, respectively, by internal steam reforming of ethanol despite of no carbon deposition condition in the equilibrium at 650 °C. Power can be generated for more than 100 h at O/C = 1.5 in butane and at S/C = 2.0 in ethanol. For internal partial oxidation reforming of methane and steam reforming of ethanol in SOFCs, the O/C and S/C ratios are significantly important to prevent carbon deposition on the Ni‐GDC anode.

Development of a Portable SOFC System with Internal Partial Oxidation Reforming of Butane and Steam Reforming of Ethanol

Internal partial oxidation reforming of butane and steam reforming of ethanol were investigated using microtubular solid oxide fuel cells (SOFCs) supported on nickel-gadolinia doped ceria (Ni-GDC) anode for portable power sources in an emergency situation and mobilities such as vehicles, robots and drones. At oxygen/carbon (O/C) ratio of 1.0, which is a coking condition in the equilibrium, the Ni-GDC anode deteriorated for 28 h by internal partial oxidation of butane at 650 oC. However, power generation was also impossible after 8 and 79 h at S/C = 1.0 and 1.5, respectively, by internal steam reforming of ethanol in spite of no carbon deposition condition in the equilibrium at 650 oC. Power can be generated over a period of more than 100 h at O/C = 1.5 in butane and at S/C = 2.0 in ethanol. The O/C and S/C ratios are significantly important to prevent carbon deposition on the Ni-GDC anode for internal partial oxidation reforming of methane and steam reforming of ethanol in SOFCs.

Development of a Portable SOFC System with Internal Partial Oxidation Reforming of Butane and Steam Reforming of Ethanol

Internal partial oxidation reforming of butane and steam reforming of ethanol were investigated using microtubular solid oxide fuel cells (SOFCs) supported on nickel-gadolinia doped ceria (Ni-GDC) anode for portable power sources in an emergency situation and mobilities such as vehicles, robots and drones. At oxygen/carbon (O/C) ratio of 1.0, the Ni-GDC anode deteriorated for 28 h by internal partial oxidation of butane at 650 oC. Furthermore, power generation was also impossible after 8 and 79 h at steam/carbon (S/C) ratios of 1.0 and 1.5, respectively, by internal steam reforming of ethanol. Power can be generated over a period of more than 100 h at O/C = 1.5 in butane and at S/C = 2.0 in ethanol. We successfully demonstrated a prototype 100 W-scale portable SOFC system fueled by liquefied petroleum gas (LPG).

Further performance enhancement of a DME-fueled solid oxide fuel cell by applying anode functional catalyst

In order to increase the coking resistance of SOFCs operating on DME fuel, a Pt/Al2O3–Ni/MgO mixture catalyst was investigated for internal partial oxidation of DME. Catalytic test demonstrated the mixture catalyst has higher activity for DME partial oxidation and lower CH4 selectivity than the individual Pt/Al2O3 and Ni/MgO catalysts. O2-TPO analysis demonstrated that the mixture catalyst also had much higher coke resistance than sintered Ni-YSZ anode, especially at high O2 to DME ratio. Raman spectroscopy of the carbon-deposited catalysts demonstrates that the graphitization degree of carbon is reduced with introducing O2 into DME, and the carbon deposited on the mixture catalyst is almost in amorphous structure. Two operation modes of the mixture catalyst for indirect internal partial oxidation of DME, i.e, directly depositing on the anode surface and locating in the anode chamber were tried. The performance of the cells operating on DME fuel through both operation modes was studied by I–V polarization test and EIS characterization. The cells delivered attractive peak power density of around 750 mW cm−2 by operating on DME-O2 mixture gas, modestly lower than 1012–1065 mW cm−2 operating on pure hydrogen fuel at 700 °C. The direct deposition of Pt/Al2O3–Ni/MgO onto anode surface to perform as a functional layer and a DME to O2 ratio of 2:1 in the mixture gas is preferred to minimize coke formation and maximize power output for the cell to operate on DME fuel.

Reducing the operation temperature of a solid oxide fuel cell using a conventional nickel-based cermet anode on dimethyl ether fuel through internal partial oxidation

Dimethyl ether (DME)-oxygen mixture as the fuel of an anode-supported SOFC with a conventional nickel-cermet anode for operating at reduced temperatures is systematically investigated. The results of the catalytic tests indicate that sintered Ni-YSZ has high activity for DME partial oxidation, and DME conversion exceeds 90% at temperatures higher than 700 °C. Maximum methane selectivity is reached at 700 °C. Cell performance is observed between 600 and 800 °C. Peak power densities of approximately 400 and 1400 mW cm −2 at 600 and 800 °C, respectively, are reached for the cell operating on DME-O 2 mixture. These values are comparable to those obtained using hydrogen as a fuel, and cell performance is reasonably stable at 700 °C for a test period of 340 min. SEM results demonstrate that the cell maintains good geometric integrity without any delimitation of respective layer after the stability test, and EDX results show that carbon deposition occurrs only at the outer surface of the anode. O 2-TPO analysis shows that carbon deposition over the Ni-YSZ operating on DME is greatly suppressed in the presence of oxygen. Internal partial oxidation may be a practical way to achieve high cell performance at intermediate-temperatures for SOFCs operating on DME fuel.

Solid oxide fuel cells operated by internal partial oxidation reforming of iso-octane

Two types of solid oxide fuel cells (SOFCs), with thin Ce 0.85Sm 0.15O 1.925 (SDC) or 8 mol% Y 2O 3-stabilized ZrO 2 (YSZ) electrolytes, were fabricated and tested with iso-octane/air fuel mixtures. An additional Ru–CeO 2 catalyst layer, placed between the fuel stream and the anode, was needed to obtain a stable output power density without anode coking. Thermodynamic analysis and catalysis experiments showed that H 2 and CO were primary reaction products at ≈750 °C, but that these decreased and H 2O and CO 2 increased as the operating temperature dropped below ≈600 °C. Power densities for YSZ cells were 0.7 W cm −2 at 0.7 V and 790 °C, and for SDC cells were 0.6 W cm −2 at 0.6 V and 590 °C. Limiting current behavior was observed due to the relatively low (≈20%) H 2 content in the reformed fuel.

Propane Fueled Solid Oxide Fuel Cells

This paper describes recent results on the operation of SOFCs with propane fuel. Two strategies have been employed. First, conventional anode supported SOFCs have been operated with propane-air mixtures. In this case, the cells operate by internal partial oxidation; for propane contents 1.7), there was no carbon deposition detected at 800°C. Power densities as high as 0.6W/cm 2 were obtained at 800°C. Second, thick-GDC-electrolyte SOFCs with ceramic-based anodes have been operated with slightly humidified propane without coking, yielding power densities up to 0.14 W/cm 2 at 750°C. These cells were cycled between propane and air several times without anode degradation.