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 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.

Direct Conversion of Coal and Coal-Derived Carbon in Fuel Cells

2004 ◽  
Author(s):  
John F. Cooper
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Conversion Efficiency ◽  
Carbon Materials ◽  
Energy Resource ◽  
Direct Conversion ◽  
Atomic Scale ◽  
Molten Carbonate Fuel Cell ◽  
Molten Carbonate ◽  
Direct Carbon Fuel Cell

A direct carbon fuel cell (DCFC) using a carbon-rich derivative of coal would maximize the conversion efficiency of this vast energy resource by avoiding the efficiency limitations of heat engines. A total conversion efficiency of 80% (based on heat of combustion of carbon) has been achieved at 30–120 mA/cm2 using carbon materials extracted from coal and other fossil resources. High experimental efficiency is grounded in two favorable aspects of the reaction thermodynamics. The net fuel cell reaction (C + O2 = CO2) has a nearly zero entropy change and therefore a theoretical efficiency of 100%. The fixed chemical potentials of carbon reactant and CO2 product make possible the full utilization of fuel in a single pass through the cell. The pure CO2 product can be used directly in enhanced oil and gas recovery, or sequestered. Historically, the development of carbon fuel cells have been limited by low anode rates, accumulation of impurities in the electrolyte, logistics of refueling, and lack of suitable cathodes. These problems are being addressed by recent developments of highly reactive carbon materials, low-cost techniques for separation of coal from ash, the possibility of pneumatic distribution of solid particulate fuel to the cells, and availability of cathodes from the molten carbonate fuel cell technology. Rate depends on atomic scale disorder and accessibility of reactive sites, but not on purity. Sources of suitable anode fuel include thermally decomposed products of (1) mechanical and chemical coal/ash separation or (2) solvent extraction. With current understanding of the cell basics, the next steps are demonstration of an engineering scale fuel cell stack (∼1 kW), supported by development of coal-to-carbon processes and techniques of electrolyte management. Successful development of a direct conversion fuel cell for coal (or coal-derived carbon) has extraordinary implications in extending the energy reserves of coal-producing nations, easing the control of regulated emissions at the plant, and expanding the use the earth’s greatest fossil resource while decreasing emissions of greenhouse gas.

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.

Study on coal-fired power plant with CO 2 capture by integrating molten carbonate fuel cell system

Energy ◽  
2016 ◽  
Vol 117 ◽  
pp. 578-589 ◽  
Author(s):  
Liqiang Duan ◽  
Kun Xia ◽  
Tao Feng ◽  
Shilun Jia ◽  
Jing Bian
Keyword(s):  
Fuel Cell ◽  
Power Plant ◽  
Cell System ◽  
Molten Carbonate Fuel Cell ◽  
Molten Carbonate ◽  
Fuel Cell System ◽  
Carbonate Fuel Cell

FULL SCALE EXPERIMENT AND NUMERICAL ANALYSIS FOR THE PERFORMANCE OF HEAT EXCHANGER IN MOLTEN CARBONATE FUEL CELLS

2016 ◽  
Vol 40 (5) ◽  
pp. 799-810
Author(s):  
Seon-Hwa Kim ◽  
Byeong-Keun Choi ◽  
Young-Su An
Keyword(s):  
Heat Exchanger ◽  
Fuel Cell ◽  
Flow Characteristics ◽  
Cell System ◽  
Molten Carbonate Fuel Cell ◽  
Molten Carbonate ◽  
Fuel Gas ◽  
Operation Conditions ◽  
Scale Down ◽  
Scale Experiment

This study presents a numerical simulation of heat transfer and flow characteristics of the heat exchanger in molten carbonate fuel cell system. In this study, the actual size of the heat exchanger was simulated in order to avoid errors that can occur from the scale-down test, also the simulation gas (air) was verified with the heat duty of 800,000 kcal/hr. It is analyzed by using a commercial heat exchanger calculation code based upon the test condition. It is found that a reasonable agreement is obtained from comparison between the predicted results and the measured data. Furthermore, the verified similarity was presented in this analysis. In particular, the simulation gas used for the shell side service for the heat exchanger is obtained through the combustion calculation, i.e. by using a flow rate of the fuel gas. In addition, the performance of the heat exchanger is predicted under various conditions in the fuel cell operation conditions by the numerical model.

Molten carbonate fuel cell system fed with biofuels for electricity production

2016 ◽  
Vol 41 (41) ◽  
pp. 18815-18821 ◽  
Author(s):  
V. Chiodo ◽  
G. Zafarana ◽  
S. Maisano ◽  
S. Freni ◽  
A. Galvagno ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Cell System ◽  
Molten Carbonate Fuel Cell ◽  
Electricity Production ◽  
Molten Carbonate ◽  
Fuel Cell System ◽  
Carbonate Fuel Cell

Numerical Analysis of a Molten Carbonate Fuel Cell Stack in Emergency Scenarios

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Arkadiusz Szczęśniak ◽  
Jarosław Milewski ◽  
Łukasz Szabłowski ◽  
Olaf Dybiński ◽  
Kamil Futyma
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Numerical Analysis ◽  
High Accuracy ◽  
Molten Carbonate Fuel Cell ◽  
Molten Carbonate ◽  
Fuel Cell Stack ◽  
Power Load ◽  
Emergency Scenarios ◽  
Carbonate Fuel Cell

Abstract Molten carbonate fuel cells (MCFCs) offer several advantages that are attracting an increasingly intense research and development effort. Recent advances include improved materials and fabrication techniques as well as new designs, flow configurations, and applications. Several factors are holding back large-scale implementation of fuel cells, though, especially in distributed energy generation, a major one being their long response time to changing parameters. Alternative mathematical models of the molten carbonate fuel cell stack have been developed over the last decade. This study investigates a generic molten carbonate fuel cell stack with a nominal power output of 1 kWel. As daily, weekly, and monthly variations in the electrical power load are expected, there is a need to develop numerical tools to predict the unit’s performance with high accuracy. Hence, a fully physical dynamic model of an MCFC stack was developed and implemented in aspen hysys 10 modeling software to enable a predictive analysis of the dynamic response. The presented model exhibits high accuracy and accounts for thermal and electrochemical processes and parameters. The authors present a numerical analysis of an MCFC stack in emergency scenarios. Further functionality of the model, which was validated using real operational data, is discussed.

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