scholarly journals Thermodynamic analysis of biofuels as fuels for high temperature fuel cells

2011 ◽  
Vol 33 (4) ◽  
pp. 41-65 ◽  
Author(s):  
Jarosław Milewski ◽  
Wojciech Bujalski ◽  
Janusz Lewandowski
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Net Present Value ◽  
Molten Carbonate Fuel Cell ◽  
Molten Carbonate ◽  
Governing Equations ◽  
Fuel Cell Performance ◽  
Advantages And Disadvantages ◽  
Performance Point

Abstract Based on mathematical modeling and numerical simulations, applicativity of various biofuels on high temperature fuel cell performance are presented. Governing equations of high temperature fuel cell modeling are given. Adequate simulators of both solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) have been done and described. Performance of these fuel cells with different biofuels is shown. Some characteristics are given and described. Advantages and disadvantages of various biofuels from the system performance point of view are pointed out. An analysis of various biofuels as potential fuels for SOFC and MCFC is presented. The results are compared with both methane and hydrogen as the reference fuels. The biofuels are characterized by both lower efficiency and lower fuel utilization factors compared with methane. The presented results are based on a 0D mathematical model in the design point calculation. The governing equations of the model are also presented. Technical and financial analysis of high temperature fuel cells (SOFC and MCFC) are shown. High temperature fuel cells can be fed by biofuels like: biogas, bioethanol, and biomethanol. Operational costs and possible incomes of those installation types were estimated and analyzed. A comparison against classic power generation units is shown. A basic indicator net present value (NPV) for projects was estimated and commented.

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.

Electrochemical Carbon Separation in a SOFC-MCFC Poly-Generation Plant With Near-Zero Emissions

2017 ◽  
Author(s):  
Luca Mastropasqua ◽  
Stefano Campanari ◽  
Jack Brouwer
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Carbon Capture ◽  
Large Scale ◽  
High Efficiency ◽  
Molten Carbonate Fuel Cell ◽  
Small Scale ◽  
Total Efficiency ◽  
Molten Carbonate

High temperature fuel cells have been studied as a suitable solution for Carbon Capture and Storage (CCS) purposes at a large scale (>100 MW). However, their modularity and high efficiency at small-scale make them an interesting solution for Carbon Capture and Utilisation at the distributed generation scale when coupled to appropriate use of CO2 (i.e., for industrial uses, local production of chemicals etc.). These systems could be used within low carbon micro-grids to power small communities in which multiple power generating units of diverse nature supply multiple products such as electricity, cooling, heating and chemicals (i.e., hydrogen and CO2). The present work explores fully electrochemical power systems capable of producing a highly pure CO2 stream and hydrogen. In particular, the proposed system is based upon integrating a Solid Oxide Fuel Cell (SOFC) with a Molten Carbonate Fuel Cell (MCFC). The use of these high temperature fuel cells has already been separately applied in the past for CCS applications. However, their combined use is yet unexplored. Moreover, both industry and US national laboratories have expressed their interest in this solution. The reference configuration proposed envisions the direct supply of the SOFC anode outlet to a burner which, using the cathode depleted air outlet, completes the oxidation of the unconverted species. The outlet of the burner is then fed to the MCFC cathode inlet which separates the CO2 from the stream. Both the SOFC and MCFC anode inlets are supplied with pre-reformed and desulfurized natural gas. The MCFC anode outlet, which is characterised by a high concentration of CO2, is fed to a CO2 separation line in which a two-stage Water Gas Shift (WGS) reactor and a PSA/membrane system respectively convert the remaining CO into H2 and remove the H2 from the exhaust stream. This has the significant advantage of achieving the required CO2 purity for liquefaction and long-range transportation without requiring the need of cryogenic or distillation plants. Moreover, the highly pure H2 stream can either be sold as transportation fuel or a valuable chemical. Furthermore, different configurations are considered with the final aim of increasing the Carbon Capture Ratio (CCR) and maximising the electrical efficiency. Moreover, the optimal power ratio between SOFC and MCFC stacks is also explored. Complete simulation results are presented, discussing the proposed plant mass and energy balances and showing the most attractive configurations from the point of view of total efficiency and CCR.

scholarly journals Study and performance test of 10 kW molten carbonate fuel cell power generation system

2021 ◽  
Author(s):  
Chengzhuang Lu ◽  
Ruiyun Zhang ◽  
Guanjun Yang ◽  
Hua Huang ◽  
Jian Cheng ◽  
...  
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Molten Carbonate Fuel Cell ◽  
Operating Voltage ◽  
Molten Carbonate ◽  
Fuel Cell Stack ◽  
Carbonate Fuel Cell

AbstractThe use of high-temperature fuel cells as a power technology can improve the efficiency of electricity generation and achieve near-zero emissions of carbon dioxide. This work explores the performance of a 10 kW high-temperature molten carbonate fuel cell. The key materials of a single cell were characterized and analyzed using X-ray diffraction and scanning electron microscopy. The results show that the pore size of the key electrode material is 6.5 µm and the matrix material is α-LiAlO2. Experimentally, the open circuit voltage of the single cell was found to be 1.23 V. The current density was greater than 100 mA/cm2 at an operating voltage of 0.7 V. The 10 kW fuel cell stack comprised 80 single fuel cells with a total area of 2000 cm2 and achieved an open circuit voltage of greater than 85 V. The fuel cell stack power and current density could reach 11.7 kW and 104.5 mA/cm2 at an operating voltage of 56 V. The influence and long-term stable operation of the stack were also analyzed and discussed. The successful operation of a 10 kW high-temperature fuel cell promotes the large-scale use of fuel cells and provides a research basis for future investigations of fuel cell capacity enhancement and distributed generation in China.

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.

scholarly journals Research on high-temperature compression and creep behavior of porous Cu–Ni–Cr alloy for molten carbonate fuel cell anodes

2015 ◽  
Vol 33 (2) ◽  
pp. 356-362 ◽  
Author(s):  
W. Li ◽  
J. Chen ◽  
H. Liang ◽  
C. Li
Keyword(s):  
High Temperature ◽  
Fuel Cell ◽  
Creep Behavior ◽  
Creep Resistance ◽  
Surface Deformation ◽  
Molten Carbonate Fuel Cell ◽  
Molten Carbonate ◽  
Deformation Bands ◽  
Fuel Cell Anodes ◽  
Carbonate Fuel Cell

AbstractThe effect of porosity on high temperature compression and creep behavior of porous Cu alloy for the new molten carbonate fuel cell anodes was examined. Optical microscopy and scanning electron microscopy were used to investigate and analyze the details of the microstructure and surface deformation. Compression creep tests were utilized to evaluate the mechanical properties of the alloy at 650 °C. The compression strength, elastic modulus, and yield stress all increased with the decrease in porosity. Under the same creep stress, the materials with higher porosity exhibited inferior creep resistance and higher steadystate creep rate. The creep behavior has been classified in terms of two stages. The first stage relates to grain rearrangement which results from the destruction of large pores by the applied load. In the second stage, small pores are collapsed by a subsequent sintering process under the load. The main deformation mechanism consists in that several deformation bands generate sequentially under the perpendicular loading, and in these deformation bands the pores are deformed by flattering and collapsing sequentially. On the other hand, the shape of a pore has a severe influence on the creep resistance of the material, i.e. every increase of pore size corresponds to a decrease in creep resistance.

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.

Optimization of a MCFC Hybrid System for Combined Production of Electricity and Hydrogen

2009 ◽  
Author(s):  
Vittorio Verda ◽  
Flavio Nicolin
Keyword(s):  
Fuel Cell ◽  
Unit Cost ◽  
Hybrid Plant ◽  
Operating Conditions ◽  
Molten Carbonate Fuel Cell ◽  
Molten Carbonate ◽  
Fuel Cell Performance ◽  
Micro Gas Turbine ◽  
Pressure Swing ◽  
Economic Objective

In this paper, a hybrid plant obtained by integrating a molten carbonate fuel cell stack with a micro gas turbine and a steam reformer is considered. The system also produces hydrogen through a pressure swing absorption system. The aim of this work is the multi-objective optimisation of the system, considering energy and economic objective functions. Possible off-design operating conditions accounting for degradation of the fuel cell performance and time variation in the biogas composition are considered, as well as variation in the ambient temperature. The results show that the operating temperature of the fuel cell is a crucial design parameter as its value strongly affects the plant efficiency, its lifetime and the unit cost of electricity.

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