Effects of Gas Flow Rate and Catalyst Loading on Polymer Electrolyte Membrane (PEM) Fuel Cell Performance and Degradation

2010 ◽  
Author(s):  
A. Chukwujekwu Okafor ◽  
Hector-Martins Mogbo
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Gas Flow ◽  
Open Circuit Voltage ◽  
Polymer Electrolyte Membrane ◽  
Open Circuit ◽  
Catalyst Loading ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
Electrolyte Membrane

In this paper, the effects of gas flow rates, and catalyst loading on polymer electrolyte membrane fuel cell (PEMFC) performance was investigated using a 50cm2 active area fuel cell fixture with serpentine flow field channels machined into poco graphite blocks. Membrane Electrode Assemblies (MEAs) with catalyst and gas flow rates at two levels each (0.5mg/cm2, 1mg/cm2; 0.3L/min, 0.5L/min respectively) were tested at 60°C without humidification. The cell performance was analyzed by taking AC Impedance, TAFEL plot, open circuit voltage, and area specific resistance measurements. It was observed that MEAs with lower gas flow rate had lesser cell resistance compared to MEAs with a higher gas flow rate. TAFEL plot shows the highest exchange current density value of −2.05 mAcm2 for MEA with 0.5mg/cm2 catalyst loading operated at reactant gas flow rate of 0.3L/min signifying it had the least activation loss and fastest reaction rate. Open circuit voltage curve shows a higher output voltage and lesser voltage decay rate for MEAs tested at higher gas flow rates.

Investigation of the Effects of Catalyst Loading and Gas Flow Rate on Polymer Electrolyte Membrane (PEM) Fuel Cell Performance and Degradation

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Anthony C. Okafor ◽  
Hector-Martins C. Mogbo
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Gas Flow ◽  
Open Circuit Voltage ◽  
Polymer Electrolyte Membrane ◽  
Open Circuit ◽  
Catalyst Loading ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
Electrolyte Membrane

In this paper, the effects of gas flow rates and catalyst loading on polymer electrolyte membrane fuel cell (PEMFC) performance was investigated using a 50 cm2active area fuel cell fixture with serpentine flow field channels machined into poco graphite blocks. Membrane electrode assemblies (MEAs) with catalyst and gas flow rates at two levels each (0.5 mg/cm2, 1 mg/cm2; 0.3 l/min, 0.5 l/min, respectively) were tested at 60 °C without humidification. The cell performance was analyzed by taking ac impedance, Tafel plot, open circuit voltage, and area specific resistance measurements. It was observed that MEAs with lower gas flow rate had lesser cell resistance compared to MEAs with a higher gas flow rate. Tafel plot shows the highest exchange current density value of 10−2.05 mA cm2 for MEA with 0.5 mg/cm2 catalyst loading tested at reactant gas flow rate of 0.3 l/min signifying it had the least activation loss and fastest reaction rate. Open circuit voltage-time curve shows a higher output voltage and lesser voltage decay rate for MEAs tested at higher gas flow rates.

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).

End Plate Effects on the Performance of PEMFCs During Cold Start Process

2021 ◽  
Author(s):  
Xiongbiao Wan ◽  
Zhigang Zhan ◽  
panxing Jiang ◽  
Yuan Yu ◽  
Chenglong Wang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Polymer Electrolyte Membrane ◽  
Supercooled Water ◽  
Cold Start ◽  
Ice Formation ◽  
Gas Flow Rate ◽  
Electrolyte Membrane ◽  
End Plate ◽  
Start Process

Abstract The efficient, fast, and reliable cold start of polymer electrolyte membrane fuel cells is one of the major challenges for their commercialization. In this paper a segmented single cell is used to simulate the end plate effects of the stack and to investigate how the effects work. The results demonstrate that the end cells in the stack have the lowest performance, the reasons for which include the lowest temperature of the cells themselves, and probably also ice blocking in part an area inside the MEA, or in the channels, or in both together. In order to mitigate or even eliminate the influence of ice formation in the end cells, the temperature of the end plates should be increased to -10℃ or above when liquid water is generated. A high inlet gas flow rate facilitates the discharge of supercooled water and is conducive to successful cold start.

Numerical Simulation of a Fluidic Oscillator for Water Removal Enhancement in PEM Fuel Cell

2008 ◽  
Author(s):  
S. H. Tseng ◽  
Y. T. Yang ◽  
J. Allen ◽  
S. L. Yang
Keyword(s):  
Fuel Cell ◽  
Gas Flow ◽  
Water Drop ◽  
Polymer Electrolyte Membrane ◽  
Water Removal ◽  
Acoustic Vibrations ◽  
Flow Rates ◽  
Fluidic Oscillator ◽  
Electrolyte Membrane ◽  
Low Temperature Fuel Cells

The fluidic oscillator is one solution to the problems of water management of the Polymer Electrolyte Membrane Fuel Cell (PEMFC). In low temperature fuel cells such as the PEMFC, liquid water is produced as a byproduct. At low gas flow rates, the water produced has a tendency to plug the reactant supply channels. When the channels are plugged, reactant supply to the catalyst sites is prohibited and results in fuel cell failure. One proposed method of removing a water drop is to oscillate the drop near its natural frequency in order to free it from the substrate. A variety of methods for oscillating the drop are available including mechanical vibrations, acoustic vibrations and flow pulsations. It is the latter method, i.e., use of the fluidic oscillator that is investigated in this study. The purpose of this paper is to use the experimental and numerical techniques to study and simulate a fluidic oscillator so that detail of flow physics inside the oscillator can be realized. Method on how to use the flow field solution to determine the oscillator response frequency is also described. Numerically results of oscillator frequency will be compared with the available experimental data.

scholarly journals Influence of Pressure on Gas/Liquid Interfacial Area in a Tray Column

2020 ◽  
Vol 10 (13) ◽  
pp. 4617
Author(s):  
Adel Almoslh ◽  
Falah Alobaid ◽  
Christian Heinze ◽  
Bernd Epple
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Volumetric Flow Rate ◽  
Interfacial Area ◽  
Gas Flow Rate ◽  
Test Rig ◽  
Flow Rates ◽  
Waste Gas ◽  
Simulated Waste ◽  
Series Of Experiments

The influence of pressure on the gas/liquid interfacial area is investigated in the pressure range of 0.2–0.3 MPa by using a tray column test rig. A simulated waste gas, which consisted of 30% CO2 and 70% air, was used in this study. Distilled water was employed as an absorbent. The temperature of the inlet water was 19 °C. The inlet volumetric flow rate of water was 0.17 m3/h. Two series of experiments were performed; the first series was performed at inlet gas flow rate 15 Nm3/h, whereas the second series was at 20 Nm3/h of inlet gas flow rate. The results showed that the gas/liquid interfacial area decreases when the total pressure is increased. The effect of pressure on the gas/liquid interfacial area at high inlet volumetric gas flow rates is more significant than at low inlet volumetric gas flow rates. The authors studied the effect of decreasing the interfacial area on the performance of a tray column for CO2 capture.

Effect of Inner Cavity’s Gas Flow Rate on the Extrusion Forming of Plastic Micro-Pipe

2020 ◽  
Vol 842 ◽  
pp. 279-284
Author(s):  
Zhong Ren ◽  
Xing Yuan Huang
Keyword(s):  
Finite Element ◽  
Normal Stress ◽  
Flow Rate ◽  
Gas Flow ◽  
Normal Stress Difference ◽  
Stress Difference ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
First Normal Stress Difference ◽  
Extrusion Forming

During the manufacture of plastic micro-pipe, a certain volume of gas should be properly injected into the inner cavity to overcome the collapse and adhesion problems. In this work, the extrusion forming of plastic micro-tube under the role of inner cavity’s gas were numerically studied. At the same time, the effect of inner cavity’s gas flow rate on the extrusion deformation of plastic micro-pipe was also numerically investigated by using the finite element method. A kind of 2D two-phase fluid geometric model and finite element mesh were established and some reasonable boundary conditions and material parameters were imposed. Under a fixed volume flow rate of melt, different flow rates of inner cavity gas were imposed on the inlet of inner cavity’s gas. The extrusion deformation profile and deformation ratio of plastic micro-pipe under different flow rates of gas were all obtained. To ascertain the mechanisms of effect of inner cavity’s gas flow rate on the extrusion deformation of plastic micro-tube, the flow velocities, pressure, shear rate, normal stress, and the first normal stress difference of melt all obtained and analyzed. Numerical results show that with the increase of inner cavity’s gas flow rate, the radial velocity, axial velocity, pressure, shear rate, normal stress, and the first normal stress difference of melt all increase, which makes the extrusion deformation become more and more serious. In practice, reasonable controlling of the inner cavity’s gas flow rate is very important. In the other hand, it can adjust the size of extruded plastic micro-pipe.

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