CATALYTIC REQUIREMENTS FOR MIXED REACTANT FUEL CELLS

2008 ◽  
Vol 01 (02) ◽  
pp. 105-113 ◽  
Author(s):  
ILAN RIESS
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Heterogeneous Catalysis ◽  
Low Temperature ◽  
Electrode Materials ◽  
Catalytic Properties ◽  
Electrochemical Reactions ◽  
Direct Reaction ◽  
Oxygen Ions

Significant advantage could be achieved if mixed reactant fuel cells, MR-FC, were functioning. These cells are intended to operate on a mixture of air and fuel introduced into both the cathode and anode compartment. Symmetry is broken by using different electrode materials exhibiting special and different catalytic properties. No high temperature fuel cell was reported to date to function as a true MR-FC and only one, low temperature type, did function properly. We discuss the required catalytic properties which are unique in that they promote electrochemical reactions and suppress chemical ones as well as possible ways to search for them. The chemical reaction which has to be suppressed is the direct reaction of fuel and oxygen as the two components are premixed and the mixture is then introduced into the fuel cell at both electrode compartments. The electrochemical reactions that should be promoted are the reduction of oxygen at the cathode and the oxidation of fuel at the anode only by oxygen ions that emerge from the solid electrolyte. Conditions to promote this selectivity are discussed. These are derived from the theory of chemisorption as applied to heterogeneous catalysis.

scholarly journals Review of Latest Developments in PEM Fuel Cell Research with Application to Hydrogen Powered Drones

2021 ◽  
Vol 19 ◽  
pp. 7-11
Author(s):  
B. Day ◽  
A. Pourmovahed ◽  
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Low Temperature ◽  
Energy Content ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Cell Systems ◽  
Cell Technology ◽  
Current State

Fuel cells are becoming an increasingly more enticing option to power drones for extended use applications. This is because under certain conditions, fuel cell systems are able to more efficiently store fuel and, therefore, energy compared to standard battery options. This reality has been proven through multiple research efforts and is reviewed in this paper. It is necessary to review the current state of PEM fuel cell technology for drone applications to determine the extent of its limitations and feasibility. For this reason, the latest developments in low temperature and high temperature PEM fuel cells were studied including their limitations and sensitivity to contamination with a focus on drone applications. It has been reported that hydrogen powered fuel cell systems are more efficient than conventional battery applications when the energy content is higher than 4 MJ. A hybrid fuel cell and battery powertrain is preferred for the purpose of counterbalancing the deficiencies of both individual cases. Currently available products were explored, and it was found that there are fuel cell systems available that are capable of powering drones in excess of 23 kg (50 lb).

Hydrogenous Fuel as an Energy Material for Efficient Operation of Tandem System Based on Fuel Cells

2016 ◽  
Vol 723 ◽  
pp. 616-621 ◽  
Author(s):  
Marina Zubkova ◽  
Alexander Stroganov ◽  
Alexander Chusov ◽  
Dmitry Molodtsov
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Low Temperature ◽  
Performance Enhancement ◽  
Material Balance ◽  
Temperature Oxidation ◽  
Efficient Operation ◽  
Energy Material ◽  
Effective Efficiency

This paper presents the results of relatively cheap hydrogenous fuel usage as an energy material for energy supply stand-alone environmentally friendly systems creation. Usage of fuel cells running on hydrogenous fuel is a promising direction in creation of stand-alone power supply systems in low-rise residential development. Presented thermodynamic calculations and material balance data for electric and thermal components assessment in considered ways to use convention products, performance enhancement in tandem system based on fuel cells with full heat regeneration. The total effective efficiency of the tandem installation including the fuel converter, separating system, high-temperature fuel cell, low-temperature fuel cell is higher than for each of the fuel cell elements separately. Distribution of H2 for LTFC and HTFC is determined in compliance with the conditions of the positive heat balance to compensate the heat used for the endoenergic reaction in the converter, input stream heating and heat losses. The total effective efficiency under making full use of recovered heat for considered tandem system depends on the efficiency of its constituent fuel cells. Energetically effective distribution of H2 on streams of high-temperature and low-temperature oxidation according to a position of observance of positive thermal balance on an external contour of tandem system, is reached by operation of HTFC electric efficiency in the range of 50 ÷ 55%.

scholarly journals Review of Latest Developments in PEM Fuel Cell Research with Application to Hydrogen Powered Drones

2021 ◽  
Vol 19 ◽  
pp. 7-11
Author(s):  
B. Day ◽  
A. Pourmovahed ◽  
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Low Temperature ◽  
Energy Content ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Cell Systems ◽  
Cell Technology ◽  
Current State

Fuel cells are becoming an increasingly more enticing option to power drones for extended use applications. This is because under certain conditions, fuel cell systems are able to more efficiently store fuel and, therefore, energy compared to standard battery options. This reality has been proven through multiple research efforts and is reviewed in this paper. It is necessary to review the current state of PEM fuel cell technology for drone applications to determine the extent of its limitations and feasibility. For this reason, the latest developments in low temperature and high temperature PEM fuel cells were studied including their limitations and sensitivity to contamination with a focus on drone applications. It has been reported that hydrogen powered fuel cell systems are more efficient than conventional battery applications when the energy content is higher than 4 MJ. A hybrid fuel cell and battery powertrain is preferred for the purpose of counterbalancing the deficiencies of both individual cases. Currently available products were explored, and it was found that there are fuel cell systems available that are capable of powering drones in excess of 23 kg (50 lb).

Submicro-pore containing poly(ether sulfones)/polyvinylpyrrolidone membranes for high-temperature fuel cell applications

2015 ◽  
Vol 3 (16) ◽  
pp. 8847-8854 ◽  
Author(s):  
Zhibin Guo ◽  
Ruijie Xiu ◽  
Shanfu Lu ◽  
Xin Xu ◽  
Shichun Yang ◽  
...  
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Exchange Membrane

A novel submicro-pore containing proton exchange membrane is designed and fabricated for application in high-temperature fuel cells.

Assessment of the Potential of Combined Micro Gas Turbine and High Temperature Fuel Cell Systems

2002 ◽  
Author(s):  
Dieter Bohn ◽  
Nathalie Po¨ppe ◽  
Joachim Lepers
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Advanced Materials ◽  
Cell Systems ◽  
Micro Gas Turbine ◽  
Technological Assessment

The present paper reports a detailed technological assessment of two concepts of integrated micro gas turbine and high temperature (SOFC) fuel cell systems. The first concept is the coupling of micro gas turbines and fuel cells with heat exchangers, maximising availability of each component by the option for easy stand-alone operation. The second concept considers a direct coupling of both components and a pressurised operation of the fuel cell, yielding additional efficiency augmentation. Based on state-of-the-art technology of micro gas turbines and solid oxide fuel cells, the paper analyses effects of advanced cycle parameters based on future material improvements on the performance of 300–400 kW combined micro gas turbine and fuel cell power plants. Results show a major potential for future increase of net efficiencies of such power plants utilising advanced materials yet to be developed. For small sized plants under consideration, potential net efficiencies around 70% were determined. This implies possible power-to-heat-ratios around 9.1 being a basis for efficient utilisation of this technology in decentralised CHP applications.

The Thermodynamic Evaluation and Optimization of Fuel Cell Systems

2006 ◽  
Vol 3 (2) ◽  
pp. 155-164 ◽  
Author(s):  
N. Woudstra ◽  
T. P. van der Stelt ◽  
K. Hemmes
Keyword(s):  
Heat Transfer ◽  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Energy Conversion ◽  
System Optimization ◽  
Fuel Conversion ◽  
Cell Systems ◽  
Electrochemical Conversion ◽  
Conversion Efficiencies

Energy conversion today is subject to high thermodynamic losses. About 50% to 90% of the exergy of primary fuels is lost during conversion into power or heat. The fast increasing world energy demand makes a further increase of conversion efficiencies inevitable. The substantial thermodynamic losses (exergy losses of 20% to 30%) of thermal fuel conversion will limit future improvements of power plant efficiencies. Electrochemical conversion of fuel enables fuel conversion with minimum losses. Various fuel cell systems have been investigated at the Delft University of Technology during the past 20 years. It appeared that exergy analyses can be very helpful in understanding the extent and causes of thermodynamic losses in fuel cell systems. More than 50% of the losses in high temperature fuel cell (molten carbonate fuel cell and solid oxide fuel cell) systems can be caused by heat transfer. Therefore system optimization must focus on reducing the need for heat transfer as well as improving the conditions for the unavoidable heat transfer. Various options for reducing the need for heat transfer are discussed in this paper. High temperature fuel cells, eventually integrated into gas turbine processes, can replace the combustion process in future power plants. High temperature fuel cells will be necessary to obtain conversion efficiencies up to 80% in the case of large scale electricity production in the future. The introduction of fuel cells is considered to be a first step in the integration of electrochemical conversion in future energy conversion systems.

Wetting properties of porous high temperature polymer electrolyte fuel cells materials with phosphoric acid

2019 ◽  
Vol 21 (24) ◽  
pp. 13126-13134 ◽  
Author(s):  
J. Halter ◽  
T. Gloor ◽  
B. Amoroso ◽  
T. J. Schmidt ◽  
F. N. Büchi
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Phosphoric Acid ◽  
Polymer Electrolyte ◽  
Polymer Electrolyte Fuel Cells ◽  
Polymer Electrolyte Fuel Cell ◽  
Wetting Behavior ◽  
Wetting Properties ◽  
Fuel Cell Materials

The influence of phosphoric acid temperature and concentration on the wetting behavior of porous high temperature polymer electrolyte fuel cell materials is investigated.

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