• Energy Research

Abstract A detailed computational model of a direct-flame solid oxide fuel cell (DFFC) is presented. The DFFC is based on a fuel-rich methane–air flame stabilized on a flat-flame burner and coupled to a solid oxide fuel cell (SOFC). The model consists of an elementary kinetic description of the premixed methane–air flame, a stagnation-point flow description of the coupled heat and mass transport within the gas phase, an elementary kinetic description of the electrochemistry, as well as heat, mass and charge transport within the SOFC. Simulated current–voltage characteristics show excellent agreement with experimental data published earlier (Kronemayer et al., 2007 [10] ). The model-based analysis of loss processes reveals that ohmic resistance in the current collection wires dominates polarization losses, while electronic loss currents in the mixed conducting electrolyte have only little influence on the polarized cell. The model was used to propose an optimized cell design. Based on this analysis, power densities of above 200 mW cm −2 can be expected.

The performance of a solid oxide fuel cell fueled with flames of combustible gases, liquids, and solids was studied. A cell structure in which cells were serially integrated within a disk was also examined. Open-circuit voltages indicated with a single cell and the integrated cell were ∼0.8 and ∼3.5 V, respectively. Maximum power density obtained with the flames of n-butane, kerosine, paraffin wax (candle), and wood were respectively 75, 65, 62, and 5 mW/cm 2 . The integrated cell gave a maximum power density of 318 mW/cm 2 with n-butane flame. Fuel to air ratio distinctly influenced the output.

Abstract This paper presents an experimental study of a direct-flame type solid oxide fuel cell (DFFC). The operation principle of this system is based on the combination of a combustion flame with a solid oxide fuel cell (SOFC) in a simple, no-chamber setup. The flame front serves as fuel reformer located a few millimeters from the anode surface while at the same time providing the heat required for SOFC operation. Experiments were performed using 13-mm-diameter planar SOFCs with Ni-based anode, samaria-doped ceria electrolyte and cobaltite cathode. At the anode, a 45-mm-diameter flat-flame burner provided radially homogeneous methane/air, propane/air, and butane/air rich premixed flames. The cell performance reaches power densities of up to 120 mW cm−2, varying systematically with flame conditions. It shows a strong dependence on cell temperature. From thermodynamic calculations, both H2 and CO were identified as species that are available as fuel for the SOFC. The results demonstrate the potential of this system for fuel-flexible power generation using a simple setup.

Propyl alcohol and butyl alcohol had similar effects to ethyl alcohol on ultrastructure of liver mitochondria. Rats were given 32% ethyl alcohol, 32% n‐propyl alcohol, and 6.9% n‐butyl alcohol in drinking water for up to three months. After one month, mitochondria in hepatocytes obtained from the experimental animals became elongated, constricted or cup‐shaped with scanty cristae. After two months, mitochondria in some hepatocytes became gigantic. In extreme cases, the megamitochondria exceeded 10 μm in diameter.Coupling efficiencies of hepatic mitochondria obtained from alcohol‐fed animals were well preserved despite their drastic morphologic changes. ACTA PATHOL. JPN. 34: 471–480, 1984.

We present a combined experimental and modeling study of a direct-flame type solid oxide fuel cell (DFFC). The operation principle of this system is based on the combination of a flame with an SOFC in a simple, no-chamber setup. Experiments were performed using 13-mm-diameter planar SOFCs with Ni-based anode, samaria-doped ceria electrolyte and cobaltite cathode. At the anode, a 7-mm-diameter flat-flame burner provided methane/air rich premixed flames. The cell performance reaches power densities of up to 200 mW/cm2. A detailed analysis of the electrical efficiency is carried out. Observed system efficiencies are below 0.5%. Equilibrium calculations of the flame exhaust gas were performed. From the simulations, both H2 and CO were identified as species that are available as fuel for the SOFC.

Abstract The operation of a pair of anode-to-anode-facing solid oxide fuel cells (SOFCs) via in situ catalytic partial oxidation (CPO) of n-butane was investigated. In this simple “no-chamber” setup, butane is partially oxidized by heterogeneous reactions inside the porous anodes, providing processed fuel and the heat required for SOFC operation. The cell couple yielded a power density of up to 270 mW cm−2, and the maximum total power obtained was 1.2 W with cell sizes of 13 mm × 23 mm. The maximum electrical efficiency was 1.3%. High CO concentrations of up to 1000 ppm were detected in the exhaust gas, indicating that the cell couple could not efficiently consume the complete provided fuel. A flame, lit at the exhaust, minimized the carbon monoxide level while having insignificant influence on the cell performance. Thermal insulation of the cell couple improved the output remarkably, showing the strong influence of temperature on cell performance. The two cells had a distance of only 2 mm, suggesting a potential for high volumetric power densities in multi-cell configurations for a self-sustained combined heat and power system.

To realize high density 3D packaging, various types of interposer including through vias are developed. Although the interposer should have a high wiring density not only horizontally but also vertically, the ability of the conventional interposers to provide high density through vias with a low cost is still quite limited. Copper-filled anodic aluminum oxide has been studied as an alternative interposer material. Stable electrical connection was confirmed with four-wiring-layer substrates. High density vias as fine as 35 μm pitch were realized as a ground-surrounded structure. This coaxial-like via structure was remarkably effective for reducing harmful noise that tends to increase with the increased via density required for high performance systems.