Parametric Studies of Microstructural Performance Effects in Solid Oxide Cells

2014 ◽  
Author(s):  
Zachary K. van Zandt ◽  
George J. Nelson
Keyword(s):  
Pore Diameter ◽  
Cell Polarization ◽  
Solid Oxide ◽  
Transfer Model ◽  
Co2 Gas ◽  
Pore Sizes ◽  
Gas Streams ◽  
Performance Effects ◽  
Parametric Studies ◽  
Electrochemical Potentials

A distributed charge transfer model has been developed to analyze solid oxide fuel cells and electrolyzers operating in H2-H2O and CO-CO2 atmospheres. The model couples mass transport based on the dusty-gas model, ion and electron transport in terms of charged species electrochemical potentials, and electrochemical reactions defined by Butler-Volmer kinetics. The model is validated by comparison to published experimental data, particularly cell polarization curves for both fuel cell and electrolyzer operation. Parametric studies have been performed to compare the effects of microstructure on the performance of SOFCs and SOECs operating in H2-H2O and CO-CO2 gas streams. Compared to the H2-H2O system, the power density of the CO-CO2 system shows a greater sensitivity to porosity and tortuosity. Analyses of the effects of the pore diameter suggest the H2-H2O and CO-CO2 systems are affected by changes in pore diameter in a similar manner. However, the concentration losses of the CO-CO2 system are significantly higher than those of the H2-H2O system for the pore sizes analyzed. While both systems can be shown to improve in performance with higher porosity, lower tortuosity, and larger pore sizes the results of these parametric studies imply that CO-CO2 systems would benefit more from such microstructural changes. These results further suggest that objectives for tailoring microstructure in solid oxide cells operating in CO-CO2 are distinct from objectives for more common H2-focused systems.

scholarly journals Solid Oxide Cell Microstructural Performance in Hydrogen and Carbon Monoxide Reactant Streams

2016 ◽  
Vol 13 (1) ◽  
Author(s):  
Zachary K. van Zandt ◽  
George J. Nelson
Keyword(s):  
Cell Polarization ◽  
Solid Oxide ◽  
Co2 Gas ◽  
Microstructural Changes ◽  
Pore Sizes ◽  
Gas Streams ◽  
Electrolysis Cells ◽  
Parametric Studies ◽  
Solid Oxide Electrolysis Cells ◽  
Solid Oxide Cell

A distributed charge transfer (DCT) model has been developed to analyze solid oxide fuel cells (SOFCs) and electrolyzers operating in H2–H2O and CO–CO2 atmospheres. The model couples mass transport based on the dusty-gas model (DGM), ion and electron transport in terms of charged species electrochemical potentials, and electrochemical reactions defined by Butler–Volmer kinetics. The model is validated by comparison to published experimental data, particularly cell polarization curves for both fuel cell and electrolyzer operation. Parametric studies have been performed to compare the effects of microstructure on the performance of SOFCs and solid oxide electrolysis cells (SOECs) operating in H2–H2O and CO–CO2 gas streams. Compared to the H2–H2O system, the power density of the CO–CO2 system shows a greater sensitivity to pore microstructure, characterized by the porosity and tortuosity. Analysis of the pore diameter concurs with the porosity and tortuosity parametric studies that CO–CO2 systems are more sensitive to microstructural changes than H2–H2O systems. However, the concentration losses of the CO–CO2 system are significantly higher than those of the H2–H2O system for the pore sizes analyzed. While both systems can be shown to improve in performance with higher porosity, lower tortuosity, and larger pore sizes, the results of these parametric studies imply that CO–CO2 systems would benefit more from such microstructural changes. These results further suggest that objectives for tailoring microstructure in solid oxide cells (SOCs) operating in CO–CO2 are distinct from objectives for more common H2-focused systems.

scholarly journals Effect of pore diameter on the elution behavior of analytes from thermoresponsive polymer grafted beads packed columns

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kenichi Nagase ◽  
Yuta Umemoto ◽  
Hideko Kanazawa
Keyword(s):  
Pore Diameter ◽  
Packed Column ◽  
Packed Columns ◽  
Butyl Methacrylate ◽  
Thermoresponsive Polymer ◽  
Thermoresponsive Polymers ◽  
Column Temperature ◽  
Pore Sizes ◽  
Temperature Responsive ◽  
Elution Behavior

AbstractTemperature-responsive chromatography using thermoresponsive polymers is innovative and can control analyte retention via column temperature. Analyte elution behavior in this type of chromatography depends on the modified thermoresponsive polymer and the structure of the base materials. In the present study, we examine the effect of the pore diameter of silica beads on analyte elution behavior in temperature-responsive chromatography. Poly(N-isopropylacrylamide-co-n-butyl methacrylate) hydrogel was applied to beads of various pore sizes: 7, 12, and 30 nm. Almost the same amount of copolymer hydrogel was applied to all beads, indicating that the efficiency of copolymer modification was independent of pore size. Analyte retention on prepared beads in a packed column was observed using steroids, benzodiazepines, and barbiturates as analytes. Analyte retention times increased with temperature on packed columns of 12- and 30-nm beads, whereas the column packed with 7-nm beads exhibited decreased retention times with increasing temperature. The difference in analyte elution behavior among the various pore sizes was attributed to analyte diffusion into the bead pores. These results demonstrate that bead pore diameter determines temperature-dependent elution behavior.

scholarly journals Combined Cycle of Solid Oxide Fuel Cell and Turbines with the Aim of Separating CO2 Gas.

1993 ◽  
Vol 59 (565) ◽  
pp. 2702-2708
Author(s):  
Sadahiro Namie ◽  
Koki Shiozaki ◽  
Masanobu Nomura ◽  
Youichi Kawagoe ◽  
Takanao Kumakura
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Combined Cycle ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Co2 Gas

scholarly journals 3D CFD Electrochemical and Heat Transfer Model of an Internally Manifolded Solid Oxide Electrolysis Cell

2011 ◽  
Author(s):  
Grant L. Hawkes ◽  
James E. O’Brien ◽  
Greg G. Tao
Keyword(s):  
Heat Transfer ◽  
Hydrogen Production ◽  
Current Density ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Electrolysis Cell ◽  
Transfer Model ◽  
Gas Composition ◽  
Solid Oxide Electrolysis ◽  
Solid Oxide Electrolysis Cell

A three-dimensional computational fluid dynamics (CFD) and electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in an internally manifolded planar solid oxide electrolysis cell (SOEC) stack. This design is being evaluated experimentally at the Idaho National Laboratory (INL) for hydrogen production from nuclear power and process heat. Mass, momentum, energy, and species conservation are numerically solved by means of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, operating potential, steam-electrode gas composition, oxygen-electrode gas composition, current density and hydrogen production over a range of stack operating conditions. Results will be presented for a five-cell stack configuration that simulates the geometry of five-cell stack tests performed at the INL and at Materials and System Research, Inc. (MSRI). Results will also be presented for a single cell that simulates conditions in the middle of a large stack. Flow enters the stack from the bottom, distributes through the inlet plenum, flows across the cells, gathers in the outlet plenum and flows downward making an upside-down “U” shaped flow pattern. Flow and concentration variations exist downstream of the inlet holes. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Contour plots of local electrolyte temperature, current density, and Nernst potential indicate the effects of heat transfer, reaction cooling/heating, and change in local gas composition. Results are discussed for using this design in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production, cell thermal efficiency, cell electrical efficiency, and Gibbs free energy are discussed and reported herein.

scholarly journals A Zero-Waste Process for the Treatment of Spent Potliner (SPL) Waste

2021 ◽  
Author(s):  
Samir I. Abu-Eishah ◽  
Manal D.M. Raheem ◽  
Fatma A.S. Aljasmi ◽  
Fatima M.O. Alameri ◽  
Amna G.R. Alblooshi ◽  
...  
Keyword(s):  
Potassium Fluoride ◽  
Weak Acid ◽  
Aluminum Fluoride ◽  
Co2 Gas ◽  
Gas Streams ◽  
Agno3 Solution ◽  
Process Gas ◽  
Hazardous Gases ◽  
Environmentally Friendly Process ◽  
Silver Cyanide

This work presents a deep analyses of an environmentally friendly process to recover all valuable minerals contained in the spent potliner (SPL) such as graphite carbon and aluminum fluoride (AlF3) and production of sodium sulfate (Na2SO4) and gypsum (CaSO4) when H2SO4 is used as the leaching agent. The level of emission of hazardous gases such as HCN (weak acid) and HF are minimized by direct scrubbing of the HCN in aqueous AgNO3 solution to produce a stable silver cyanide (AgCN) product. The HF can be recovered as a liquid by condensation and used within the process and/or in production of metal fluorides such as the highly-soluble potassium fluoride (KF); a main source of fluoride in industry. Almost pure CO2 gas is also recovered from the process gas streams.

Effect of water vapor generation on cell polarization in active area of anode-supported solid oxide fuel cells

2019 ◽  
Vol 56 (2) ◽  
pp. 617-625
Author(s):  
Jungmyung Kim ◽  
Ehtesham Ali ◽  
Minwoo Kim ◽  
Hyungtae Lim ◽  
Heesung Park
Keyword(s):  
Fuel Cells ◽  
Water Vapor ◽  
Solid Oxide Fuel Cells ◽  
Cell Polarization ◽  
Solid Oxide ◽  
Active Area ◽  
Oxide Fuel ◽  
Vapor Generation ◽  
Effect Of Water

Parametric Studies of the Thermal Performance of a Tape Ball Grid Array (TBGA) Package

2000 ◽  
Author(s):  
Sandeep S. Tonapi ◽  
Sanjeev B. Sathe ◽  
K. Srihari ◽  
Bahgat B. Sammakia
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Heat Dissipation ◽  
Physical Phenomenon ◽  
Ball Grid Array ◽  
Cover Plate ◽  
Transfer Model ◽  
Back Side ◽  
Significant Difference ◽  
Parametric Studies

Abstract This paper deals with parametric studies to evaluate the thermal performance of a Tape Ball Grid Array (TBGA) package. A cover plate is attached to the back side of the chip to enhance heat transfer from the module. The package is attached to an organic carrier and placed in a vertical channel. A conjugate heat transfer model is used accounting for conduction in the package and the card and convection in the surrounding air. The effect of location of the TBGA on a card with 0, 1 and 2 power planes is evaluated for thermal performance. Five different locations of the TBGA on the card are investigated. Heat dissipation is studied for forced convection (2, 1, and 0.5m/s). No significant difference in chip junction temperatures for the different locations is observed. Temperature distribution along the card centerline and the module centerline are used to discuss the physical phenomenon that is occurring.

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