Modeling of a Methane Fuelled Direct Carbon Fuel Cell System

2005 ◽  
Author(s):  
K. Hemmes ◽  
M. Houwing ◽  
N. Woudstra
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Production Efficiency ◽  
Cell System ◽  
Total System ◽  
Carbon Particles ◽  
Direct Carbon Fuel Cell ◽  
Air Stream ◽  
Reactive Carbon ◽  
Outlet Stream

Direct Carbon Fuel Cells (DCFCs) have great thermodynamic advantages over other high temperature fuel cells such as MCFC and SOFC. They can have 100% fuel utilization, no Nernst loss (at the anode) and the CO2 produced at the anode is not mixed with other gases and is ready for reuse or sequestration. So far only studies have been reported on cell development. In this paper we study in particular the integration of the production of clean and reactive carbon particles from methane as a fuel for the direct carbon fuel cell. In the thermal decomposition process heat is upgraded to chemical energy in the carbon and hydrogen produced. The hydrogen is seen as a product as well as the power and heat. Under the assumptions given the net system electric efficiency is 22.9 % (based on methane LHV) and 20.7 % (HHV). The hydrogen production efficiency is 65.5 % (based on methane LHV) and 59.1 % (HHV), which leads to a total system efficiency of 88.4 % (LHV) and 79.8 % (HHV). Although a pure CO2 stream is produced at the anode outlet, which is seen as a large advantage of DCFC systems, this advantage is unfortunately reduced due to the need for CO2 in the cathode air stream. Due to the applied assumed constraint that the cathode outlet stream should at least contain 4% CO2 for a proper functioning of the cathode, similar to MCFC cathodes a major part of the pure CO2 has to be mixed with incoming air. Further optimization of the DCFC and the system is needed to obtain a larger fraction of the output streams as pure CO2 for sequestration or reuse.

Modeling of a Methane Fuelled Direct Carbon Fuel Cell System

2010 ◽  
Vol 7 (6) ◽  
Author(s):  
K. Hemmes ◽  
M. Houwing ◽  
N. Woudstra
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Cell System ◽  
Molten Carbonate Fuel Cell ◽  
Total System ◽  
Molten Carbonate ◽  
Heating Value ◽  
Carbon Particles ◽  
Direct Carbon Fuel Cell ◽  
Air Stream

Direct Carbon Fuel Cells (DCFCs) have great thermodynamic advantages over other high temperature fuel cells such as molten carbonate fuel cell (MCFC) and solid oxide fuel cell. They can have 100% fuel utilization, no Nernst loss (at the anode), and the CO2 produced at the anode is not mixed with other gases and is ready for re-use or sequestration. So far only studies have been reported on cell development. In this paper we study in particular the integration of the production of clean and reactive carbon particles from methane as a fuel for the direct carbon fuel cell. In the thermal decomposition process heat is upgraded to chemical energy in the carbon and hydrogen produced. The hydrogen is seen as a product as well as the power and heat. Under the assumptions given the net system electric efficiencies are 22.9% (based on methane lower heating value, LHV) and 20.7% (higher heating value, HHV). The hydrogen production efficiencies are 65.5% (based on methane LHV) and 59.1% (HHV), which leads to total system efficiencies of 88.4% (LHV) and 79.8% (HHV). Although a pure CO2 stream is produced at the anode outlet, which is seen as a large advantage of DCFC systems, this advantage is unfortunately reduced due to the need for CO2 in the cathode air stream. Due to the applied assumed constraint that the cathode outlet stream should at least contain 4% CO2 for the proper functioning of the cathode, similar to MCFC cathodes, a major part of the pure CO2 has to be mixed with incoming air. Further optimization of the DCFC and the system is needed to obtain a larger fraction of the output streams as pure CO2 for sequestration or re-use.

Modeling of a Direct Carbon Fuel Cell System

2010 ◽  
Vol 7 (5) ◽  
Author(s):  
K. Hemmes ◽  
M. Houwing ◽  
N. Woudstra
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Exergy Analysis ◽  
Cell System ◽  
System Model ◽  
System Level ◽  
Molten Carbonate ◽  
Bench Scale ◽  
Direct Carbon Fuel Cell ◽  
Molten Carbonate Fuel Cells

Direct carbon fuel cells (DCFCs) have great thermodynamic advantages over other high temperature fuel cells such as molten carbonate fuel cells (MCFCs) and solid oxide fuel cells. They can have 100% fuel utilization, no Nernst loss (at the anode), and the CO2 produced at the anode is not mixed with other gases and is ready for re-use or sequestration. So far, only studies have been reported on cell development. In this paper, we study the performance of a CO2-producing DCFC system model. The theoretically predicted advantages that are confirmed on a bench scale are also confirmed on a system level, except for the production of pure CO2. Net system efficiencies of around 78% were found for the developed system. An exergy analysis of the system shows where the losses in the system occur. If the cathode of the DCFC must be operated as a standard MCFC cathode, the required CO2 at the cathode is the reason why a large part of the pure CO2 from the anode is recycled and mixed with the incoming air and cannot be used directly for sequestration. Bench scale studies should be performed to test the minimum amount of CO2 needed at the cathode. This might be lower than in a standard MCFC operation due to the pure CO2 at the anode side that enhances diffusion toward the cathode.

Fuel Cells as Energy Sources for Future Mobile Devices

2006 ◽  
Vol 3 (4) ◽  
pp. 492-494 ◽  
Author(s):  
Sari Tasa ◽  
Teppo Aapro
Keyword(s):  
Energy Source ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Mobile Devices ◽  
Mobile Device ◽  
Environmental Performance ◽  
Cell System ◽  
Fuel Cell System ◽  
Cell Technology ◽  
Fuel Cell Technology

Mobile device manufacturers would like to provide totally wireless solutions—including charging. Future multimedia devices need to have longer operation times as simultaneously they require more power. Device miniaturization leaves less volumetric space available also for the energy source. The energy density of the Li-ion batteries is high, and continuously developed, but not at the same speed as the demand from devices. Fuel cells can be one possible solution to power mobile devices without connection to the mains grid, but they will not fit to all use cases. The fuel cell system includes a core unit, fuel system, controls, and battery to level out peaks. The total energy efficiency is the sum of the performance of the whole system. The environmental performance of the fuel cell system cannot be determined yet. Regulatory and standardization work is on-going and driving the fuel cell technology development. The main target is in safety, which is very important aspect for energy technologies. The outcomes will also have an effect on efficiency, cost, design, and environmental performance. Proper water, thermal, airflow, and fuel management of the fuel cell system combined with mechanical durability and reliability are the crucial enablers for stable operation required from the integrated power source of a mobile device. Reliability must be on the same level as the reliability of the device the energy source is powering; this means years of continuous operation time. Typically, the end-users are not interested of the enabling technologies nor understand the usage limits. They are looking for easy to use devices to enhance their daily life. Fuel cell technology looks promising but there are many practical issues to be solved.

scholarly journals Thermodynamic Effects of Nanotechnological Augmentation of Hydrogen Fuel Cells

2017 ◽  
Vol 4 ◽  
pp. 76-86 ◽  
Author(s):  
Reece Cohen Woodley ◽  
Kane Yang ◽  
Geoffrey Bruce Tanner ◽  
Dennis Tran
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Cell System ◽  
Thermodynamic Efficiency ◽  
Hydrogen Fuel Cells ◽  
Hydrogen Fuel ◽  
Fuel Cell System ◽  
Efficient System ◽  
Structured Catalysts ◽  
Thermodynamic Effects

This meta-study focuses on the research regarding the use of nanotechnology in traditional fuel cells in order to increase thermodynamic efficiency through the exploitation of various thermodynamic systems and theories. The use of nanofilters and nano-structured catalysts improve the fuel cell system through the means of filtering molecules from protons and electrons significantly increases the possible output of the fuel cell and the use of nano-platinum catalysts to lower the activation energy of the fuel cell chemical reaction a notable amount resulting in a more efficient system and smaller entropy in comparison to the use of macro sized catalysts.

Modeling of a Direct Carbon Fuel Cell System

2005 ◽  
Author(s):  
K. Hemmes ◽  
M. Houwing ◽  
N. Woudstra
Keyword(s):  
Fuel Cells ◽  
Exergy Analysis ◽  
Cell System ◽  
System Model ◽  
System Level ◽  
Anode Side ◽  
Fuel Utilization ◽  
Fuel Cell System ◽  
Bench Scale ◽  
Direct Carbon Fuel Cell

Direct Carbon Fuel Cells (DCFCs) have great thermodynamic advantages over other high temperature fuel cells such as MCFC and SOFC. They can have 100% fuel utilization, no Nernst loss (at the anode) and the CO2 produced at the anode is not mixed with other gases and is ready for reuse or sequestration. So far only studies have been reported on cell development. In this paper we study the performance of a CO2-producing DCFC system model. The theoretically predicted advantages that are confirmed on a bench scale are also confirmed on a system level, except for the production of pure CO2. Net system efficiencies of around 78 % were found for the developed system. An exergy analysis of the system shows where the losses in the system occur. If the cathode of the DCFC must be operated as a standard MCFC cathode the required CO2 at the cathode is the reason why a large part of the pure CO2 from the anode is recycled and mixed with the incoming air and cannot be used directly for sequestration. Bench scale studies should be performed to test the minimum amount of CO2 needed at the cathode. This might be lower than in standard MCFC operation due to the pure CO2 at the anode side that enhances diffusion towards the cathode.

A Numerical Investigation of Heat and Mass Transfer in Air-Cooled Proton Exchange Membrane Fuel Cells

2019 ◽  
Author(s):  
Torsten Berning
Keyword(s):  
Heat Transfer ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Waste Heat ◽  
Proton Exchange ◽  
Fuel Cell Performance ◽  
Air Stream ◽  
Multi Phase ◽  
Exchange Membrane

Abstract A numerical analysis of an air-cooled proton exchange membrane fuel cell (PEMFC) has been conducted. The model utilizes the Eulerian multi-phase approach to predict the occurrence and transport of liquid water inside the cell. It is assumed that all the waste heat must be carried out of the fuel cell with the excess air which leads to a strong temperature increase of the air stream. The results suggest that the performance of these fuel cells is limited by membrane overheating which is ultimately caused by the limited heat transfer to the laminar air stream. A proposed remedy is the placement of a turbulence grid before such a fuel cell stack to enhance the heat transfer and increase the fuel cell performance.

Systems Analysis of Diesel Based Fuel Cells for Auxiliary Power Units

2003 ◽  
Author(s):  
David A. Berry ◽  
Robert James ◽  
Todd H. Gardner ◽  
Dushyant Shekhawat
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Diesel Fuel ◽  
Systems Analysis ◽  
Cell System ◽  
Sulfur Poisoning ◽  
Ongoing Research ◽  
Auxiliary Power ◽  
Auxiliary Power Units ◽  
The Impact

The near-term commercial success for many fuel cell technologies will rely on their ability to utilize current infrastructure fuels. Several large ready-markets exist for fuel cell systems that utilize middle distillate petroleum fractions like diesel fuel. One particular application is diesel-based auxiliary power units (APU). Unfortunately, very little research and development has been devoted to this application. Ongoing research at the National Energy Technology Laboratory (NETL) and other organizations is trying to address this need. In order for a fuel cell to utilize diesel fuel, it must be reformed into a synthesis gas containing primarily hydrogen, carbon monoxide, carbon dioxide, steam and possibly methane. Because catalytic reforming of hydrocarbon fuels is conducted at the same relative operating temperatures of technologies like solid oxide fuel cells (800–1000°C) a high degree of thermal integration is possible. Unfortunately, carbon deposition and sulfur poisoning of catalysts in the reformer and fuel cell make system operation potentially complicated and costly. To help understand and quantify the impact of these issues on technology development and component, a number of systems analysis was conducted for a diesel-based fuel cell system. One particular system based on a hybrid combustor/reformer concept allowed for excellent utilization of available heat from the fuel cell and yielded an overall fuel to electric conversion efficiency of nearly 50%. This paper discusses its salient features and compares its characteristics to other possible system configurations.

Direct Alcohol Fuel Cell for Automotive Applications and Vehicle Modeling

2004 ◽  
Author(s):  
M. O. Branda˜o ◽  
S. C. A. Almeida
Keyword(s):  
Fuel Cells ◽  
Control System ◽  
Fuel Cell ◽  
Cell System ◽  
Automotive Applications ◽  
Fuel Cell System ◽  
Super Capacitor ◽  
Vehicle Modeling ◽  
Direct Alcohol Fuel Cell ◽  
Alcohol Fuel

This paper describes the study made by COPPE/UFRJ which goal is the development of fuel cells systems for automotive applications. The study is divided in two parts. The first is the development of a PEM direct fuel cell. In addition a method for experimentally determine the possibility of using a fuel in a fuel cell is developed. The components of catalysts are also tested such as Tin and Ruthenium in a Platinum coated electrode. The second part is the control system for a fuel cell powered vehicle. The vehicle power is modeled from its actions and losses. A power of 80kW seems to be a great choice if made of 50kW from the fuel cell system and 30kW from an accumulator such as a pack of batteries or a super capacitor.

scholarly journals Measurements Based Analysis of the Proton Exchange Membrane Fuel Cell Operation in Transient State and Power of Own Needs

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 498
Author(s):  
Andrzej Wilk ◽  
Daniel Węcel
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Transient State ◽  
Experimental Tests ◽  
Cell System ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Variable Load ◽  
Exchange Membrane

Currently, fuel cells are increasingly used in industrial installations, means of transport, and household applications as a source of electricity and heat. The paper presents the results of experimental tests of a Proton Exchange Membrane Fuel Cell (PEMFC) at variable load, which characterizes the cell’s operation in real installations. A detailed analysis of the power needed for operation fuel cell auxiliary devices (own needs power) was carried out. An analysis of net and gross efficiency was carried out in various operating conditions of the device. The measurements made show changes in the performance of the fuel cell during step changing or smooth changing of an electric load. Load was carried out as a change in the current or a change in the resistance of the receiver. The analysis covered the times of reaching steady states and the efficiency of the fuel cell system taking into account auxiliary devices. In the final part of the article, an analysis was made of the influence of the fuel cell duration of use on obtained parameters. The analysis of the measurement results will allow determination of the possibility of using fuel cells in installations with a rapidly changing load profile and indicate possible solutions to improve the performance of the installation.

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