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 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 Developmental Status of Hybrids

1999 ◽  
Author(s):  
Abbie Layne ◽  
Scott Samuelsen ◽  
Mark Williams ◽  
Patricia Hoffman
Keyword(s):  
Power Generation ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Gas Turbine ◽  
High Efficiency ◽  
Combined Cycle ◽  
Pollutant Emission ◽  
Distributed Power Generation ◽  
Power Generation Technology ◽  
Generation Technology

Fuel cells are emerging as a major new power generation technology that is particularly suitable for distributed power generation, high-efficiency, and low pollutant emission. An interesting combined cycle, the “HYBRID,” has recently been scoped “on paper” that portends the potential of ultra-high efficiency (approaching 80%) in which a gas turbine is synergistically combined with a fuel cell into a unique combined cycle. This paper introduces hybrid technology to the gas turbine community as a whole, and summarizes the current and projected activities associated with this emerging concept.

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.

CFD Simulations of Flow and Pressure Distributions in Column Flow Type Fuel Cells

2006 ◽  
Author(s):  
Paul Ridenour ◽  
Zhigi Ma ◽  
Naresh Kumar Selvarasu ◽  
Eugene S. Smotkin ◽  
Chenn Q. Zhou
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Flow Rate ◽  
New Technology ◽  
Volumetric Flow Rate ◽  
Electrical Energy ◽  
Pressure Drops ◽  
Fuel Cell Performance ◽  
Pressure Distributions ◽  
Flow Channels

Fuel cells are a growing new technology that can be applied in order to harness electrical energy out of hydrogen and hydrated air. When testing these devices however, pressure drops along the apparatus are strongly discouraged due to the fluctuation in gas volumetric flow rate that they incur. The design of the flow channels is critical to the fuel cell performance and water management. In this research, computational fluid dynamics (CFD) is used to analyze the gas manifold and a column channel inside of a fuel cell. The effect of the flow channel parameters on the flow rate and pressure drops are investigated to provide useful information to optimize the design of flow channels.

scholarly journals Parametric Study of Fuel Cell and Gas Turbine Combined Cycle Performance

1997 ◽  
Author(s):  
Dawn Stephenson ◽  
Ian Ritchey
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Solid Oxide ◽  
Simple Cycle ◽  
Cycle Performance ◽  
Oxide Fuel ◽  
Combined Cycles

A number of cycles have been proposed in which a solid oxide fuel cell is used as the topping cycle to a gas turbine, including those recently described by Beve et al. (1996). Such proposals frequently focus on the combination of particular gas turbines with particular fuel cells. In this paper, the development of more general models for a number of alternative cycles is described. These models incorporate variations of component performance with key cycle parameters such as gas turbine pressure ratio, fuel cell operating temperature and air flow. Parametric studies are conducted using these models to produce performance maps, giving overall cycle performance in terms of both gas turbine and fuel cell design point operating conditions. The location of potential gas turbine and fuel cell combinations on these maps is then used to identify which of these combinations are most likely to be appropriate for optimum efficiency and power output. It is well known, for example, that the design point of a gas turbine optimised for simple cycle performance is not generally optimal for combined cycle gas turbine performance. The same phenomenon may be observed in combined fuel cell and gas turbine cycles, where both the fuel cell and the gas turbine are likely to differ from those which would be selected for peak simple cycle efficiency. The implications of this for practical fuel cell and gas turbine combined cycles and for development targets for solid oxide fuel cells are discussed. Finally, a brief comparison of the economics of simple cycle fuel cells, simple cycle gas turbines and fuel cell and gas turbine combined cycles is presented, illustrating the benefits which could result.

Highlights of Fuel Cell Modeling From a Lattice Boltzmann Method Point of View

2014 ◽  
Author(s):  
Mayken Espinoza ◽  
Bengt Sundén ◽  
Martin Andersson
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
High Efficiency ◽  
Electrical Energy ◽  
Proton Exchange ◽  
Cell Modeling ◽  
Fuel Cell Modeling ◽  
Boltzmann Method

Relative simplicity of use, no pollutions and high-efficiency are some of the advantages that will make fuel cells one of the best devices for getting electrical energy in the near future. Micro- and mesoscale modeling of fuel cells gives an important perspective about their efficiency and behavior during the energy conversion process. Due to the high cost of carrying out laboratory experiments related to different materials at the micro- and mesoscales, modeling and simulation of the different elements of the fuel cells are a useful approach and a point of departure for the experimental validation. This paper describes fuel cell modeling starting with the fundamentals, including physical and chemical characteristics of fuel cells, moving to the current state of the study of modeling based on the Lattice Boltzmann Method (LBM). The principal characteristics and elements of the fuel cells are presented in general as well as the main differences between the Proton Exchange Membrane Fuel Cells (PEMFC) and Solid Oxide Fuel Cells (SOFC). Fuel cells have several parts that are modeled on the micro- and mesoscale level. These parts, conditions and governing equations for different transport phenomena are displayed in this manuscript. A detailed description of the main issues, advantages and recent advances related to Lattice Boltzmann Method as a method for modeling several physical processes that take place within fuel cells are presented.

Comparison of a Multi-Megawatt High Temperature Fuel Cell System With Reciprocating Engines and Aero-Derivative Gas Turbines

2008 ◽  
Author(s):  
Georgia C. Karvountzi ◽  
Paul F. Duby
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid System ◽  
Gas Turbines ◽  
Cell System ◽  
Combined Cycle ◽  
Simple Cycle ◽  
Fuel Cell System

High temperature fuel cells can be successfully integrated in a simple cycle or in a combined cycle configuration and achieve lower heating value (LHV) efficiencies greater than gas turbines and reciprocating engines. A simple cycle fuel cell system reaches 50 to 51% LHV efficiencies. A fuel cell system integrated with gas and steam turbines in a hybrid system could lead to LHV efficiencies of 70% to 72%. An aero-derivative gas turbine that is the most efficient simple cycle gas turbine achieves 40% to 46% thermal efficiency and a new generation reciprocating engine 39% to 42%. Upon integration in a combined cycle configuration with steam injection, aero-derivative gas turbines potentially reach LHV efficiencies of 55% to 58%. The purpose of the present paper is to compare initially the performance of a stand alone fuel cell with a stand alone gas turbine and a stand alone reciprocating engine. Then the fuel cell is integrated in a hybrid system and it is compared with a gas turbine combined cycle plant. The system sizes explored are 5MW in the stand alone case, and 20MW, 30MW, 60MW, 100MW and 200MW in the hybrid / combined cycle case. The performance of the hybrid system was reviewed under different ambient temperatures (0° F–90° F) and site elevations (0 ft–3000 ft). High temperature fuel cells are more efficient and have lower emissions than gas turbines and reciprocating engines. However fuel cells cannot be used for peak power generation due to long start-up time or load following applications.

Study of a Hybrid Solid Oxide Fuel Cell: Energetic Analysis and Sankey Diagram

2004 ◽  
Author(s):  
Jose´ Luz-Silveira ◽  
Antonio Carlos Caetano de Souza ◽  
Giulliano Batelochi Gallo
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Energy Production ◽  
Hydrocarbon Fuel ◽  
Combined Cycle ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Energetic Analysis ◽  
Decentralized Energy

In this paper a hybrid solid oxide fuel cell (SOFC) system is analyzed. This system applies a combined cycle utilizing gas turbine associated to a SOFC for rational decentralized energy production. Initially the relative concepts about the fuel cell are presented, followed by some chemical and technical informations such as the change of Gibbs free energy in isothermal fuel oxidation (or combustion) directly into electricity. This represents a very high fraction of the lower heating value (LHV) of a hydrocarbon fuel. In the next step a methodology for the study of SOFC associated with a gas turbine system is developed, considering the electricity and steam production for a hospital, as regard to the Brazilian conditions. This methodology is applied to energetic analysis. Natural gas is considered as a fuel. In conclusion, it is shown by a Sankey Diagram that the hybrid SOFC system may be an excellent opportunity to strengthen the decentralized energy production in Brazil. It is necessary to consider that the cogeneration in this version also is a sensible alternative from the technical point of view, demanding special methods of design, equipment selection and mainly of the contractual deals associated to electricity and fuel supply.

scholarly journals Design Analysis of Hybrid Gas Turbine‒Fuel Cell Power Plant in Stationary and Marine Applications

2020 ◽  
Vol 27 (2) ◽  
pp. 107-119
Author(s):  
Tomasz Kwaśniewski ◽  
Marian Piwowarski
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Power Plant ◽  
Gas Turbine ◽  
High Efficiency ◽  
Design Analysis ◽  
Gas Temperature ◽  
Regenerative Heat ◽  
Fuel Cell Stack ◽  
Marine Applications

AbstractThe paper concerns the design analysis of a hybrid gas turbine power plant with a fuel cell (stack). The aim of this work was to find the most favourable variant of the medium capacity (approximately 10 MW) hybrid system. In the article, computational analysis of two variants of such a system was carried out. The analysis made it possible to calculate the capacity, efficiency of both variants and other parameters like the flue gas temperature. The paper shows that such hybrid cycles can theoretically achieve extremely high efficiency over 60%. The most favourable one was selected for further detailed thermodynamic and flow calculations. As part of this calculation, a multi-stage axial compressor, axial turbine, fuel cell (stack) and regenerative heat exchanger were designed. Then an analysis of the profitability of the installation was carried out, which showed that the current state of development of this technology and its cost make the project unprofitable. For several years, however, tendencies of decreasing prices of fuel cells have been observed, which allows the conclusion that hybrid systems will start to be created. This may apply to both stationary and marine applications. Hybrid solutions related to electrical power transmission, including fuel cells, are real and very promising for smaller car ferries and shorter ferry routes.

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