Nonconventional Fuels for High-Temperature Fuel Cells: Status and Issues

2009 ◽  
Vol 6 (2) ◽  
Author(s):  
V. Cigolotti ◽  
S. McPhail ◽  
A. Moreno
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Anaerobic Digestion ◽  
System Integration ◽  
Energy Use ◽  
Alternative Fuel ◽  
System Level ◽  
Operational Experience ◽  
Practical Case

The pressing environmental and political necessities of modern international society call for a suitable array of contingency solutions to the energy question. One valid alternative to fossil fuels, for example, is the use of alternative or nonconventional fuels, derived from waste or biomass. Combining these resources with fuel cell applications would provide a significant contribution to environmentally friendly and efficient energy use. Through a comprehensive literature survey and the collection of practical case studies and operational experience, an assessment of the potential for coupling with high-temperature fuel cells of three technologies of alternative fuel production—landfill, anaerobic digestion, and gasification—has been attempted. Though landfill is the easiest technology, anaerobic digestion produces superior quality gas and has the benefit of yielding extra fertilizer, in the form of digestate. Gasification is the most demanding of the technologies but is very flexible in its feedstock. Furthermore, using steam as a gasifying agent produces high quality syngas. However, the main issue with all three technologies is the removal of contaminants, in particular, sulfur. The application of high-temperature gas cleanup is demonstrated to bring considerable advantages on system level when gasification of nonconventional fuels is considered. Ultimately, the reforming step is a key aspect for optimal cost-effective integration of these alternative systems. The review provided establishes the key characteristics of alternative fuel conversion by landfill, anaerobic digestion, and gasification, and exposes the major points of attention for their subsequent application in high-temperature fuel cells. Indications of the measures required and the developments in the field of basic research and system integration are given to provide clear paths of activity, which should bring about the wide-scale implementation of a truly promising application of fuel cell systems.

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.

Robotic Material Handling of Flexible Fuel Cell Membranes

2005 ◽  
Author(s):  
Stephen J. Derby ◽  
John Lippiatt
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Material Handling ◽  
Cell Membranes ◽  
Fuel Cell Membranes ◽  
New Approaches ◽  
Free Mode ◽  
Fabric Handling ◽  
Very High

One of the biggest challenges in the manufacturing of high temperature fuel cells is the creation of the Membrane Exchange Assembly (MEA). This is the heart of the fuel cell, where the 4–5 components must be assembled with very high tolerances to perform successfully. One of the key components, the membrane, is similar to plastic food wrap. Handling plastic wrap alone in a wrinkle free mode, with precision cut edges is difficult enough. But it also must be saturated in acid, creating a very slippery product. And the membrane will grow or shrink in a matter of 5 minutes when exposed to moisture in the air. So this material handling effort is orders of magnitude more difficult than the established methods for “simple” items like paper. This paper will document the research conducted into the robotic material handling of the fuel cell membranes. It requires a mix of traditional robotic techniques, some techniques from the fabric handling arena, and some new approaches. The issues from lifting a wet film from a PET backer sheet consistently and the sensing requirements for accurate placement have made this a challenging effort.

Power Cycle Integration and Efficiency Increase of Molten Carbonate Fuel Cell Systems

2005 ◽  
Vol 3 (4) ◽  
pp. 375-383 ◽  
Author(s):  
Petar Varbanov ◽  
Jiří Klemeš ◽  
Ramesh K. Shah ◽  
Harmanjeet Shihn
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Gas Turbines ◽  
Waste Heat ◽  
Combined Cycle ◽  
Molten Carbonate Fuel Cell ◽  
Steam Turbines ◽  
Molten Carbonate ◽  
Carbonate Fuel Cell

A new view is presented on the concept of the combined cycle for power generation. Traditionally, the term “combined cycle” is associated with using a gas turbine in combination with steam turbines to better utilize the exergy potential of the burnt fuel. This concept can be broadened, however, to the utilization of any power-generating facility in combination with steam turbines, as long as this facility also provides a high-temperature waste heat. Such facilities are high temperature fuel cells. Fuel cells are especially advantageous for combined cycle applications since they feature a remarkably high efficiency—reaching an order of 45–50% and even close to 60%, compared to 30–35% for most gas turbines. The literature sources on combining fuel cells with gas and steam turbines clearly illustrate the potential to achieve high power and co-generation efficiencies. In the presented work, the extension to the concept of combined cycle is considered on the example of a molten carbonate fuel cell (MCFC) working under stationary conditions. An overview of the process for the MCFC is given, followed by the options for heat integration utilizing the waste heat for steam generation. The complete fuel cell combined cycle (FCCC) system is then analyzed to estimate the potential power cost levels that could be achieved. The results demonstrate that a properly designed FCCC system is capable of reaching significantly higher efficiency compared to the standalone fuel cell system. An important observation is that FCCC systems may result in economically competitive power production units, comparable with contemporary fossil power stations.

Design and Experimental Characterization of a High-Temperature Proton Exchange Membrane Fuel Cell Stack

2011 ◽  
Vol 8 (5) ◽  
Author(s):  
Robert Radu ◽  
Nicola Zuliani ◽  
Rodolfo Taccani
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Single Cells ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Pure Hydrogen ◽  
Exchange Membrane

Proton exchange membrane (PEM) fuel cells based on polybenzimidazole (PBI) polymers and phosphoric acid can be operated at temperature between 120 °C and 180 °C. Reactant humidification is not required and CO content up to 1% in the fuel can be tolerated, only marginally affecting performance. This is what makes high-temperature PEM (HTPEM) fuel cells very attractive, as low quality reformed hydrogen can be used and water management problems are avoided. From an experimental point of view, the major research effort up to now was dedicated to the development and study of high-temperature membranes, especially to development of acid-doped PBI type membranes. Some studies were dedicated to the experimental analysis of single cells and only very few to the development and characterization of high-temperature stacks. This work aims to provide more experimental data regarding high-temperature fuel cell stacks, operated with hydrogen but also with different types of reformates. The main design features and the performance curves obtained with a three-cell air-cooled stack are presented. The stack was tested on a broad temperature range, between 120 and 180 °C, with pure hydrogen and gas mixtures containing up to 2% of CO, simulating the output of a typical methanol reformer. With pure hydrogen, at 180 °C, the considered stack is able to deliver electrical power of 31 W at 1.8 V. With a mixture containing 2% of carbon monoxide, in the same conditions, the performance drops to 24 W. The tests demonstrated that the performance loss caused by operation with reformates, can be partially compensated by a higher stack temperature.

Optimization of an Integrated SOFC-Fuel Processing System for Aircraft Propulsion

2012 ◽  
Vol 9 (4) ◽  
Author(s):  
Thomas E. Brinson ◽  
Juan C. Ordonez ◽  
Cesar A. Luongo
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Processing System ◽  
Solid Oxide ◽  
System Level ◽  
Small Scale ◽  
Oxide Fuel ◽  
Fuel Processing ◽  
Aircraft Propulsion

As fuel cells continue to improve in performance and power densities levels rise, potential applications ensue. System-level performance modeling tools are needed to further the investigation of future applications. One such application is small-scale aircraft propulsion. Both piloted and unmanned fuel cell aircrafts have been successfully demonstrated suggesting the near-term viability of revolutionizing small-scale aviation. Nearly all of the flight demonstrations and modeling efforts are conducted with low temperature fuel cells; however, the solid oxide fuel cell (SOFC) should not be overlooked. Attributing to their durability and popularity in stationary applications, which require continuous operation, SOFCs are attractive options for long endurance flights. This study presents the optimization of an integrated solid oxide fuel cell-fuel processing system model for performance evaluation in aircraft propulsion. System parameters corresponding to maximum steady state thermal efficiencies for various flight phase power levels were obtained through implementation of the particle swarm optimization (PSO) algorithm. Optimal values for fuel utilization, air stoichiometric ratio, air bypass ratio, and burner ratio, a four-dimensional optimization problem, were obtained while constraining the SOFC operating temperature to 650–1000 °C. The PSO swarm size was set to 35 particles, and the number of iterations performed for each case flight power level was set at 40. Results indicate the maximum thermal efficiency of the integrated fuel cell-fuel processing system remains in the range of 44–46% throughout descend, loitering, and cruise conditions. This paper discusses a system-level model of an integrated fuel cell-fuel processing system, and presents a methodology for system optimization through the particle swarm algorithm.

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