Modeling of Micro-Tubular Flame-Assisted Fuel Cells

2020 ◽  
Author(s):  
Rhushikesh Ghotkar ◽  
Ryan J. Milcarek
Keyword(s):  
Fuel Cells ◽  
Power Density ◽  
Current Density ◽  
Equivalence Ratio ◽  
Density Variation ◽  
Open Circuit ◽  
Experimental Results ◽  
Equilibrium Analysis ◽  
Ohmic Loss ◽  
Concentration Loss

Abstract Direct flame fuel cells were developed in 2004 and there have been many iterations of them ever since. One of the latest iterations are the micro-tubular flame-assisted fuel cells. Even though there has been significant experimental research characterizing the performance and polarization losses of flame-assisted fuel cells, there is no model that describes their polarization losses. A model is thus developed and presented in this paper to assess the polarization losses and performance of flame-assisted fuel cells. Voltage and power density variation with current density are the main parameters that are analyzed in this paper. A model for calculating activation, ohmic and polarization losses is developed. Experimental parameters from previously published work like dimensions of the fuel cell layers, the fuel and oxidizer flow rates, the charge transfer coefficient and the exchange current density are used to optimize the model. The FFC is assumed to be a lumped system and a zero dimensional model is thus developed. The model was able to achieve an accuracy up to 95%, which adds to its credibility. The fuel-rich combustion exhaust composition is predicted using chemical equilibrium analysis for the equivalence ratios of 1.25 to 1.4 with intervals of 0.5 at 800°C. The model predicts that the open circuit voltage decreases from 0.94 to 0.89 for the equivalence ratios of 1.4 to 1.25, respectively, which matches experimental results. The model also predicts that the maximum power density decreases with decrease in equivalence ratio. Negligible activation loss was observed in the results while the ohmic loss didn‘t vary significantly with equivalence ratio. The concentration loss increased with decrease in equivalence ratio, which also matches with experimental results.

Fabrication and Characterization of Anode-Supported SDC Film Electrolyte and its Single Cell

2010 ◽  
Vol 177 ◽  
pp. 407-410
Author(s):  
Xi Bao Li ◽  
Jian Wang ◽  
Xiao Hua Yu ◽  
Hong Xing Gu ◽  
Gang Qin Shao
Keyword(s):  
Single Cell ◽  
Power Density ◽  
Flow Rate ◽  
Current Density ◽  
Tape Casting ◽  
Threshold Value ◽  
Interface Layer ◽  
Open Circuit ◽  
Discharge Performance ◽  
Film Electrolyte

NiO-YSZ (NiO-yttria stabilized zirconia, 3:2, wt.%) and samaria doped ceria (SDC) tapes were prepared by aqueous tape casting. NiO-YSZ anode-supported SDC film electrolyte half-cell was fabricated by laminating and co-sintering at 1400°C for 2 h. The single cell was prepared after LSCF-SDC (lanthanum strontium cobalt ferrite-SDC, 1:1, wt.%) cathode was coated on the electrolyte surface and sintered at 1300 °C for 2 h. The discharge performance of the single cell was tested from 500 °C to 800 °C at different H2 flow rate. Results showed that the relationship between current (I) of and H2 flow rate (ν) was I = 8 × 106 ν. Before reaching the threshold value of H2 flow rate, the current density of single cell increased with the increasing of H2 flow rate. However, the current density did not change with increasing of H2 flow rate over the threshold value. The open circuit voltage (OCV) of single cell at 500°C, 600°C, 700°C, 800°C was 0.978, 0.921, 0.861, 0.803 V, respectively. The maximum power density reached 93.03 mW/cm2 at 800°C. The resistance of interface layer between Ni-YSZ anode and SDC electrolyte was the key impact on the power density.

Fabrication and Performance Evaluation of Miniaturized Proton Exchange Membrane (PEM) Fuel Cells

2003 ◽  
Author(s):  
Tao Zhang ◽  
Pei-Wen Li ◽  
Qing-Ming Wang ◽  
Laura Schaefer ◽  
Minking K. Chyu
Keyword(s):  
Mass Transfer ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Free Convection ◽  
Current Density ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Cathode Side ◽  
Ohmic Loss ◽  
Fuel Cell Performance

Two types of miniaturized PEM fuel cells are designed and characterized in comparison with a compact commercial fuel cell device in this paper. One has Nafion® membrane electrolyte sandwiched by two brass bipolar plates with micromachined meander-like gas channels. The cross-sectional area of the gas flow channel is approximately 250 by 250 (μm). The other uses the same Nafion® membrane and anode structure, but in stead of the brass plate, a thin stainless steel plate with perforated round holes is used at cathode side. The new cathode structure is expected to allow oxygen (air) being supplied by free-convection mass transfer. The characteristic curves of the fuel cell devices are measured. The activation loss and ohmic loss of the fuel cells have been estimated using empirical equations. Critical issues such as flow arrangement, water removing and air feeding modes concerning the fuel cell performance are investigated in this research. The experimental results demonstrate that the miniaturized fuel cell with free air convection mode is a simple and reliable way for fuel cell operation that could be employed in potential applications although the maximum achievable current density is less favorable due to limited mass transfer of oxygen (air). The relation between the fuel cell dimensions and the maximum achievable current density is also discussed with respect to free-convection mode of air feeding.

Separate Measurement of Current Density Under the Channel and the Shoulder in PEM Fuel Cells

2007 ◽  
Author(s):  
Lin Wang ◽  
Hongtan Liu
Keyword(s):  
Fuel Cells ◽  
Diffusion Layer ◽  
Current Density ◽  
Electrical Resistance ◽  
High Current Density ◽  
Gas Diffusion Layer ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Experimental Results

In a proton exchange membrane (PEM) fuel cell current density under the shoulder can be very different from that under the gas channel and the knowledge of where the current density is higher is critical in flow field designs in order to optimize cell performance. Yet, up to date this issue has not been resolved. In this study, a novel yet simple approach was adopted to directly measure the current densities under the channel and the shoulder in PEM fuel cells separately. In this approach, the cathode catalyst layer was so designed that either the area under the shoulder or the area under the channel was loaded with catalyst. Such a design guaranteed the currents generated under the shoulder and the channel could be measured separately. Experimental results showed that the current density produced under the channel was lower than that under the shoulder except in the high current density region. To determine whether the lateral electrical resistance of the gas diffusion layer (GDL) was the causes for lower current density under the channel, an additional set of experiments were conducted. In this set of experiments, a silver mesh was added on the top of the gas diffusion layer (GDL) and the experimental results showed that GDL lateral electrical resistance was not the cause and it had a negligible effect on lateral current density distribution.

Glucose Oxidation by Nano-Fibrous Anodes in a Fuel Cell

2008 ◽  
Author(s):  
Pinchas Schechner ◽  
Eugenia Bubis ◽  
Hana Faiger ◽  
Eyal Zussman ◽  
Ehud Kroll
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Power Density ◽  
Peak Power ◽  
Open Circuit Voltage ◽  
Volume Ratio ◽  
Open Circuit ◽  
High Area ◽  
Micrometer Size ◽  
Oxidation Of Glucose

This work adds more experimental evidence regarding the feasibility of using glucose to fuel fuel-cells with anodes that have a high area-to-volume ratio. Electrospinning was used to fabricate sub-micrometer size fibrous electrocatalytic anode membranes for the oxidation of glucose in an alkaline fuel cell (AFC). The fibers of the membranes were made of polyacrylonitrile (PAN) and coated with silver by electroless plating. The anodes were tested while installed in a membranless fuel cell. The results presented include the open circuit voltage, OCV, the polarization curve, the power density as a function of the current density, and the peak power density, PPD. The measurements were performed with constant concentrations of glucose, 0.8 M, and KOH electrolyte solution, 1M. The performance of the anodes was found to improve as the diameter of the silver-plated fibers decreased. The highest PPD of 0.28 mW/cm2 was obtained with an anode made of plated fibers having a mean fiber diameter of 130 nanometers. We conclude from the results that saccharides in general, and glucose in particular, can serve as fuels for fuel cells, and that silver-plated polymeric electrospun electrodes have advantages due to their large surface area.

scholarly journals Effect of cell structure and heat pretreating of the microorganisms on performance of a microbial fuel cell

2019 ◽  
Vol 79 (9) ◽  
pp. 1746-1754 ◽  
Author(s):  
Milad Kadivarian ◽  
Ali A. Dadkhah ◽  
Mohsen Nasr Esfahany
Keyword(s):  
Fuel Cells ◽  
Power Density ◽  
Cross Section ◽  
Microbial Fuel Cells ◽  
Cell Structure ◽  
Open Circuit ◽  
Cod Removal ◽  
Electricity Production ◽  
Oil Refineries ◽  
Heat Pretreatment

Abstract While microbial fuel cells are being considered as a tool for energy saving in wastewater treatment facilities, such applications in oil refineries pose a challenge due to harder acclimation of microorganisms. In this research, the effect of heat pretreating mixed culture microorganisms (MCM), and cell cross section, on the performance of a novel cell design with two cross sections (single chamber microbial fuel cells, with circular: SCMFC_CC and rectangular: SCMFC_RC cross section) fed batched with refinery wastewater were investigated. First, using original and heat pretreated MCM, the performance of SCMFC_CC in terms of chemical oxygen demand (COD) removal and electricity production was investigated. Then, using only the heat pretreated MCM, the electricity production of SCMFC_RC was measured and compared with that of SCMFC_CC. Heat pretreatment of MCM improved maximum open circuit voltage (OCV) and maximum power density generated by 14% and 16%, respectively. However, heat pretreatment reduced COD removal by about 4%. The performance of SCMFC_CC in terms of maximum OCV and power density compared to SCMFC_RC was improved by 41% and 279%, respectively. Heat treatment of MCM increases the electricity generation of the cell, while reducing the performance of COD reduction due to decreasing the microorganism varieties in the MCM.

Protonated state and synergistic role of Nd3+ doped barium cerate perovskite for the enhancement of ionic pathways in novel sulfonated polyethersulfone for H2/O2 fuel cells

Soft Matter ◽  
2020 ◽  
Vol 16 (17) ◽  
pp. 4220-4233 ◽  
Author(s):  
R. Gayathri ◽  
M. Ramesh Prabhu
Keyword(s):  
Fuel Cells ◽  
Power Density ◽  
Current Density ◽  
Barium Cerate ◽  
Doped Barium Cerate ◽  
Sulfonated Polyethersulfone

1.8 times higher current density and power density were obtained for a Nd3+ doped barium cerate membrane compared to pure SPES.

scholarly journals Water management improvement in PEM fuel cells via addition of PDMS or APTES polymers to the catalyst layer

2020 ◽  
Vol 44 (5) ◽  
pp. 1227-1243
Author(s):  
Hande UNGAN ◽  
Ayşe BAYRAKÇEKEN YURTCAN
Keyword(s):  
Water Management ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Power Density ◽  
Current Density ◽  
Catalyst Layer ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Hydrophobic Polymers ◽  
A Current

Water management is one of the obstacles in the development and commercialization of proton exchange membrane fuel cells (PEMFCs). Sufficient humidification of the membrane directly affects the PEM fuel cell performance. Therefore, 2 different hydrophobic polymers, polydimethylsiloxane (PDMS) and (3-Aminopropyl) triethoxysilane (APTES), were tested at different percentages (5, 10, and 20 wt.%) in the catalyst layer. The solution was loaded onto the surface of a 25 BC gas diffusion layer (GDL) via the spraying method. The performance of the obtained fuel cells was compared with the performance of the commercial catalyst. Characterizations of each surface, including different amounts of PDMS and APTES, were performed via scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analyses. Molecular bond characterization was examined via Fourier transform infrared spectroscopy (FTIR) analysis and surface hydrophobicity was measured via contact angle measurements. The performance of the fuel cells was evaluated at the PEM fuel cell test station and the 2 hydrophobic polymers were compared. Surfaces containing APTES were found to be more hydrophobic. Fuel cells with PDMS performed better when compared to those with APTES. Fuel cells with 5wt.% APTES with a current density of 321.31 mA/cm2and power density of 0.191 W/cm2, and 10wt.% PDMS with a current density of 344.52 mA/cm2and power density of 0.205 W/cm2 were the best performing fuel cells at 0.6V.

scholarly journals UKM2 Chlorella sp. Strain Electricity Performance as Bio-anode under Different Light Wavelength in a Biophotovoltaic Cell

2020 ◽  
Vol 49 (12) ◽  
pp. 3229-3241
Author(s):  
Aisyah Nadhirah Juhari ◽  
Muhd Syazwan Sharani ◽  
Wan Ramli Wan Daud ◽  
Tahereh Jafary ◽  
Mimi Hani Abu Bakar
Keyword(s):  
Power Generation ◽  
Power Density ◽  
Current Density ◽  
Red Light ◽  
Oxygen Demand ◽  
Open Circuit ◽  
Maximum Power ◽  
Trophic Conditions ◽  
Chlorella Sp ◽  
Power Curves

A biophotovoltaic cell (BPV) is an electrobiochemical system that utilises a photosynthetic microorganism for instance is algae to trap sunlight energy and convert it into electricity. In this study, a local algae strain, UKM2 Chlorella sp. was grown in a BPV under different trophic conditions and light wavelengths. Once the acclimatisation phase succeeded, and biofilm formed, power generation by UKM2 algae at the autotrophic mode in synthetic Bold’s Basal media (BBM) under white, blue and red lights were tested. Polarisation and power curves were generated at these different conditions to study the bioelectrochemical performance of the system. Later, the condition switched to algal mixotrophic nutritional mode, with palm oil mill effluent (POME) as substrate. Maximum power generation obtained when using UKM2 in BBM under red light where a power density of 1.19 ± 0.16 W/m3 was obtained at 25.74 ± 3.89 A/m3 current density, while the open circuit voltage OCV reached 226.08 ± 8.71 mV. UKM2 in POME under blue light recorded maximum power density of 0.85 ± 0.18 W/m3 at current density of 16.75 ± 3.54 A/m3, while the OCV reached 214.05 ± 23.82 mV. Chemical oxygen demand (COD) removal reached an efficiency of 35.93%, indicating the ability of wastewater treatment and electricity generation in BPV at the same time.

Low-Temperature Direct Propane Polymer Electrolyte Membrane Fuel Cell (DPFC)

2006 ◽  
Author(s):  
Sudharsan Bharath
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Low Temperature ◽  
Current Density ◽  
Open Circuit Voltage ◽  
Polymer Electrolyte Membrane ◽  
Open Circuit ◽  
Maximum Power Density ◽  
Silicotungstic Acid ◽  
Electrolyte Membrane

The low-temperature Direct Propane Polymer Electrolyte Membrane Fuel Cell (DPFC) based on low-cost modified membranes was demonstrated for the first time. The propane is fed into the fuel cell directly without the need for reforming. A PBI membrane doped with acid and a Nafion 117 membrane modified or non-modified with silicotungstic acid were used as the polymer membranes. The anode was based on Pt, Pt-Ru or Pt/CrO3 electro catalysts and the cathode was based on a Pt electro catalyst. For non-optimized fuel cells based on H2SO4 doped PBI membranes and Pt/CrO3 anode, the open circuit potential was 1.0 Volt and the current density at 0.40 Volt was 118 mA.cm-2 at 95°C. For fuel cells based on Nafion 117 membranes modified with silicotungstic acid and on Pt/CrO3, the open-circuit voltage was 0.98 Volt and the current density at 0.40 Volt was 108 mA.cm-2 while fuel cells based on non-modified Nafion 117 membranes exhibited an open-circuit voltage of 0.8 Volt and the current density at 0.40 Volt was 42 mA.cm-2. It was also shown that propane fuel cells using anodes based on Pt-Ru/C anode (42 mW.cm-2) exhibit a similar maximum power density to that exhibited by fuel cells based on Pt-CrO3/C-anode (46 mW.cm-2), while DPFC using a Pt/C-based anode exhibited lower maximum power density (18 mW.cm-2) than fuel cells based on the Pt-CrO3/C anode (46 mW.cm-2).

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