Comparison Between MCFC/Gas Turbine and MCFC/Steam Turbine Combined Power Plants

2003 ◽  
Author(s):  
Roberto Bove ◽  
Piero Lunghi
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Power Plants ◽  
High Efficiency ◽  
Electric Energy ◽  
Thermodynamic Efficiency ◽  
Molten Carbonate ◽  
Advantages And Disadvantages

Worldwide, the main power source to produce electric energy is represented by fossil fuels, principally used at the present time in large combustion power plants. The main environmental impacts of fossil fuel-fired power plants are the use of non-renewable resources and pollutants emissions. An improvement in electric efficiency would yield a reduction in emissions and resources depletion. In fact, if efficiency is raised, in order to produce an amount unit of electric energy, less fuel is required and consequently less pollutants are released. Moreover, higher efficiency leads to economic savings in operating costs. A generally accepted way of improving efficiency is to combine power plants’ cycles. If one of the combined plants is represented by a fuel cell, both thermodynamic efficiency and emissions level are improved. Fuel cells, in fact, are ultra-clean high efficiency energy conversion devices because no combustion occurs in energy production, but only electrochemical reactions and consequently no NOx and CO are produced inside the cell. Moreover, the final product of the reaction is water that can be released into the atmosphere without particular problems. Second generation fuel cells (Solid Oxide FC and Molten Carbonate FC) are particularly suitable for combining cycles, due to their high operating temperature. In previous works, the authors had analyzed the possibility of combining Molten Carbonate Fuel Cell (MCFC) plant with a Gas Turbine and then a MCFC with a Steam Turbine Plant. Results obtained show that both these configurations allow to obtain high conversion efficiencies and reduced emissions. In the present work, a comparison between MCFC-Gas Turbine and MCFC-Steam Turbine is conducted in order to evaluate the main advantages and disadvantages in adopting one solution instead of the other one.

scholarly journals Exergy analysis of combined cycle of gas turbine and solid oxide fuel cell in different compression ratios

2016 ◽  
Vol 4 (2) ◽  
pp. 43
Author(s):  
Esmaeel Fatahian ◽  
Navid Tonekaboni ◽  
Hossein Fatahian
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Gas Turbine ◽  
Energy Production ◽  
High Efficiency ◽  
Production Systems ◽  
New Technology ◽  
Electrical Energy ◽  
Combined Cycle ◽  
Advantages And Disadvantages

Due to the growing trend of energy consumption in the world uses of methods and new energy production systems with high efficiency and low emissions have been prioritized. Today, with the development of different systems of energy production, different techniques such as the use of solar energy, wind energy, fuel cells, micro turbines and diesel generators in cogeneration have been considered, each of these methods has its own advantages and disadvantages. Having a reliable energy generation system, inexpensive and availability the use of fuel cells as a major candidate has been introduced. Fuel cells converting chemical energy to electrical energy that today are one as a new technology in energy production are considered. In this paper fuel cell compression ratios 4, 4.1 and 4.2 at an ambient temperature of 298 K have been simulated and ultimately optimum ratio 4.1 for modeling has been selected. All components of cycle, including the stack of fuel cell, combustion chamber, air compressors, recuperator and gas turbine was evaluated from the viewpoint of exergy and exergy destruction rate was calculated by EES software.

Comparison of Molten Carbonate and Solid Oxide Fuel Cells for Integration in a Hybrid System for Cogeneration or Tri-Generation

2004 ◽  
Author(s):  
Georgia C. Karvountzi ◽  
Clifford M. Price ◽  
Paul F. Duby
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cells ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Molten Carbonate ◽  
Hybrid Cycle

High temperature fuel cells, such as molten carbonate fuel cells (MCFC) and solid oxide fuel cells (SOFC) can be integrated in a hybrid cycle with a gas turbine and a steam turbine and achieve overall lower heating value (LHV) efficiencies of about 70%. A hybrid cycle designed for cogeneration or tri-generation applications could lead to even higher overall LHV efficiencies. Tri-generation is the combined generation of power, heat and cooling from the same fuel source. The purpose of the present paper is to compare the performance of a 20MW MCFC system and a 20MW tubular SOFC system and assess their potential to cogeneration and tri-generation applications. The system includes a fuel cell, a gas turbine, a multiple pressure heat recovery steam generator (HRSG), a steam turbine and an absorption chiller (for cooling). The systems were designed and sized using GatecycleTM heat balance software by GE Enter Software, LLC. In order to optimize each system we developed curves showing LHV “electric” and “cogeneration” efficiency versus power for different ratios of “MCFC and SOFC fuel cell-to-gas turbines size.” At atmospheric pressure and at 675°C (1247°F) the 20MW MCFC system achieves “electric” efficiency of 69.5%. The SOFC at the same pressure and at 980°C achieves 67.3% “electric” efficiency. The MCFC alone is more efficient (58%) than the SOFC alone (56%). However the SOFC produces more heat than the MCFC leading to slightly higher cogeneration and tri-generation efficiencies. Pressurized operation at 9atm boosts the performance of the SOFC system to higher efficiencies (70.5%). Pressurized operation is problematic for the MCFC due to increased cathode corrosion leading to cathode dissolution as well as sealant and interconnection problems. However we can pressurize the MCFC system independently of the fuel cell with the integration of a gas turbine with a compressor pressure ratio of 10 to 16. Thus we achieve efficiencies close to 69%. In conclusion SOFC is more efficiently integrated in a hybrid configuration with gas turbine and a steam turbine for trigeneration applications when pressurized. MCFC is more efficiently integrated at atmospheric and pressures below 6 atm.

High Efficiency Gas Turbine Based Power Cycles—A Study of the Most Promising Solutions: Part 2—A Parametric Performance Evaluation

2008 ◽  
Author(s):  
Rakesh K. Bhargava ◽  
Michele Bianchi ◽  
Stefano Campanari ◽  
Andrea De Pascale ◽  
Giorgio Negri di Montenegro ◽  
...  
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Gas Turbine ◽  
High Efficiency ◽  
Combined Cycle ◽  
Development Work ◽  
Brayton Cycle ◽  
Molten Carbonate ◽  
Water Steam

In general, two approaches have been used in the gas turbine industry to improve Brayton cycle performance. One approach includes increasing Turbine Inlet Temperature (TIT) and cycle pressure ratio (β), but it is quite capital intensive requiring extensive research and development work, advancements in cooling (of turbine blades and hot gas path components) technologies, high temperature materials and NOx reducing methods. The second approach involves modifying the Brayton cycle. However, this approach did not become very popular because of the development of high efficiency gas turbine (GT) based combined cycle systems in spite of their high initial cost. This paper discusses another approach that has gained lot of momentum in recent years in which modified Brayton cycles are used with humidification or water/steam injection, termed “wet Cycles”, resulting in lower cost/kW power system, or with fuel cells, obtaining “hybrid Cycles”; the cycle efficiency can be comparable with a corresponding combined cycle system including better part-load operational characteristics. Such systems, that include advanced Steam Injected cycle and its variants (STIG, ISTIG, etc.), Recuperated Water Injection cycle (RWI), humidified air turbine cycle (HAT) and Cascaded Humidified Advanced Turbine (CHAT) cycle, Brayton cycle with high temperature fuel cell, Molten Carbonate Fuel Cell (MSFC) or Solid Oxide Fuel Cells (SOFC) and combinations of these with the modified Brayton cycles, have not yet become commercially available as more development work is required. The main objective of this paper is to provide a detailed parametric thermodynamic cycle analysis of the above mentioned cycles and discussion of their comparative performance including advantages and limitations.

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.

Comparative Analysis of Conventional and Fuel Cell-Based Gas Turbine Power Plants

2013 ◽  
Author(s):  
Mohamed Gadalla ◽  
Nabil Al Aid
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
Power Plants ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Integrated System ◽  
Power Cycles ◽  
Technical Management ◽  
Advantages And Disadvantages ◽  
Gas Turbine Power Plant

The purpose of this paper is to conduct a complete comparative, energy and 2nd low analyses between different types of fuel cells integrated with a gas turbine power plant. Different levels of modeling for the solid oxide fuel cell (SOFC), the proton exchange membrane fuel cell (PEMFC) and the integrated systems are to be presented. The overall system performance is analyzed by employing individual models and further applying energy and exergetic analyses for different configurations of gas turbine power cycles. The study includes applying different proposed methods and techniques to enhance the overall efficiency of the integrated cycle. After performing the complete technical management of the complete system, a comparative study between conventional and PEMFC and SOFC cycles is investigated to highlight the corresponding advantages and disadvantages of each system. The following systems are tested and evaluated: (a) Conventional Gas Turbine System with a combustion Chamber (b) Integrated SOFC Stack into a Gas Turbine System (c) The Proposed Integrated System with both SOFC and PEMFC.

scholarly journals Effect of Cell Size on the Performance and Temperature Distribution of Molten Carbonate Fuel Cells

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1361 ◽  
Author(s):  
Jae-Hyeong Yu ◽  
Chang-Whan Lee
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Gas Flow ◽  
High Efficiency ◽  
Cross Flow ◽  
Current Density Distribution ◽  
Maximum Temperature ◽  
Similar Distribution ◽  
Molten Carbonate ◽  
Molten Carbonate Fuel Cells

Molten carbonate fuel cells (MCFCs) are high-operating-temperature fuel cells with high efficiency and fuel diversity. Electrochemical reactions in MCFCs are exothermic. As the size of the fuel cells increases, the amount of the heat from the fuel cells and the temperature of the fuel cells increase. In this work, we investigated the relationship between the fuel cell stack size and performance by applying computational fluid dynamics (CFD). Three flow types, namely co-flow, cross-flow, and counter-flow, were studied. We found that when the size of the fuel cells increased beyond a certain value, the size of the fuel cell no longer affected the cell performance. The maximum fuel cell temperature converged as the size of the fuel cell increased. The temperature and current density distribution with respect to the size showed a very similar distribution. The converged maximum temperature of the fuel cells depended on the gas flow condition. The maximum temperature of the fuel cell decreased as the amount of gas in the cathode size increased.

Advances in the Research and Development of Fuel Cells in China

2004 ◽  
Author(s):  
Chong-Fang Ma ◽  
Hang Guo ◽  
Fang Ye ◽  
Jian Yu
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Research And Development ◽  
Proton Exchange Membrane ◽  
High Efficiency ◽  
Direct Methanol Fuel Cells ◽  
Proton Exchange ◽  
Molten Carbonate ◽  
Direct Methanol ◽  
The Government

As a clean, high efficiency power generation technology, fuel cell is a promising choice of next generation power device. Widely application of fuel cells will make a contribution to save fuels and reduce atmospheric pollution. In recent years, fuel cells science, technology and engineering have attracted great interest in China. There are more and more Chinese scientists and engineers embark upon fuel cell projects. The government also encourages academic institutions and companies to enter into this area. Research and development of fuel cells are growing rapidly in China. There are many chances and challenges in fuel cells’ research and development. The state of the art of research and development of fuel cells in China was overviewed in this paper. The types of fuel cells addressed in this paper included alkaline fuel cells, phosphoric acid fuel cells, molten carbonate fuel cells, solid oxide fuel cells, proton exchange membrane fuel cells and direct methanol fuel cells.

Molten Carbonate Fuel Cells for Retrofitting Postcombustion CO2 Capture in Coal and Natural Gas Power Plants

2018 ◽  
Vol 15 (3) ◽  
Author(s):  
Maurizio Spinelli ◽  
Stefano Campanari ◽  
Stefano Consonni ◽  
Matteo C. Romano ◽  
Thomas Kreutz ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Natural Gas ◽  
Co2 Capture ◽  
Power Plants ◽  
Combined Cycle ◽  
Co2 Separation ◽  
Molten Carbonate ◽  
Promising Alternative ◽  
Molten Carbonate Fuel Cells

The state-of-the-art conventional technology for postcombustion capture of CO2 from fossil-fueled power plants is based on chemical solvents, which requires substantial energy consumption for regeneration. A promising alternative, available in the near future, is the application of molten carbonate fuel cells (MCFC) for CO2 separation from postcombustion flue gases. Previous studies related to this technology showed both high efficiency and high carbon capture rates, especially when the fuel cell is thermally integrated in the flue gas path of a natural gas-fired combined cycle or an integrated gasification combined cycle plant. This work compares the application of MCFC-based CO2 separation process to pulverized coal fired steam cycles (PCC) and natural gas combined cycles (NGCC) as a “retrofit” to the original power plant. Mass and energy balances are calculated through detailed models for both power plants, with fuel cell behavior simulated using a 0D model calibrated against manufacturers' specifications and based on experimental measurements, specifically carried out to support this study. The resulting analysis includes a comparison of the energy efficiency and CO2 separation efficiency as well as an economic comparison of the cost of CO2 avoided (CCA) under several economic scenarios. The proposed configurations reveal promising performance, exhibiting very competitive efficiency and economic metrics in comparison with conventional CO2 capture technologies. Application as a MCFC retrofit yields a very limited (<3%) decrease in efficiency for both power plants (PCC and NGCC), a strong reduction (>80%) in CO2 emission and a competitive cost for CO2 avoided (25–40 €/ton).

Ultralow Carbon Dioxide Emission MCFC Based Power Plant

2011 ◽  
Vol 8 (3) ◽  
Author(s):  
Daniele Chiappini ◽  
Luca Andreassi ◽  
Elio Jannelli ◽  
Stefano Ubertini
Keyword(s):  
Power Generation ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Gas Turbine ◽  
Combustion Engine ◽  
Carbon Dioxide Emission ◽  
Internal Combustion ◽  
Molten Carbonate Fuel Cell ◽  
Plant Performance ◽  
Molten Carbonate

The application of high temperature fuel cells in stationary power generation seems to be one of the possible solutions to the problem related to the environment preservation and to the growing interest for distributed electric power generation. Great expectations have been placed on both simple and hybrid fuel cell plants, thus making necessary the evolution of analysis strategies to evaluate thermodynamic performance, design improvements, and acceleration of new developments. This paper investigates the thermodynamic potential of combining traditional internal combustion energy systems (i.e., gas turbine and internal combustion engine) with a molten carbonate fuel cell for medium- and low-scale electrical power productions with low CO2 emissions. The coupling is performed by placing the fuel cell at the exhaust of the thermal engine. As in molten carbonate fuel cells the oxygen-charge carrier in the electrolyte is the carbonate ion, part of the CO2 in the gas turbine flue gas is moved to the anode and then separated by steam condensation. Plant performance is evaluated in function of different parameters to identify optimal solutions. The results show that the proposed power system can be conveniently used as a source of power generation.

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