Near-Zero CO2 Emissions Power Plant Based on High Temperature Fuel Cells

2019 ◽  
Author(s):  
Roberto Carapellucci ◽  
Roberto Cipollone ◽  
Davide Di Battista
Keyword(s):  
Carbon Dioxide ◽  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Power Plant ◽  
Energy Conversion ◽  
Gas Turbine ◽  
Co2 Emissions ◽  
Cathode Side ◽  
Energy Conversion Systems

Abstract The recent awareness on the environmental issues related to global warming is leading to the search for always more efficient energy conversion systems and, mainly, with very low carbon dioxide emissions. In fact, they are strictly related to the combustion reaction of fossil fuels which is the main process of the actual power generation technology. In this regard, fuel cells are energy conversion systems which are characterized by higher efficiency and near-zero CO2 emissions. Their novel integration with conventional power plants participates to the concept of the decarbonization of the economy. In this work, the integration of two high temperature fuel cells (HTFC) with a gas turbine power plant has been proposed and investigated, thanks to the combination of a physical model of the fuel cells and a numerical one of the components involved in the gas turbine cycle. In the layout studied, fresh air is compressed, pre-heated and used in a Solid Oxide Fuel Cell (SOFC), where the high operating temperature and the exothermic process give exhaust gases at very high temperatures, suitable for an expansion in a turbine. After the expansion, the gases are rich of CO2 and, so, they can be sent to the cathode side of a Molten Carbonate Fuel Cell (MCFC). Hence, the so-defined integrated plant is composed by three power units: a turbine, a SOFC and a MCFC; operating pressure, fuel need, oxygen and carbon dioxide utilizations in the fuel cells are parameterized in order to optimize the whole plant and find additional room of energy exploitation. Moreover, the MCFC acts as an active device for carbon separation, introducing further environmental benefits.

Hybrid Gas Turbine and Fuel Cell Systems in Perspective Review

1999 ◽  
Author(s):  
David J. White
Keyword(s):  
Carbon Dioxide ◽  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid Systems ◽  
Gas Turbines ◽  
Energy Output ◽  
Net Energy ◽  
Cell Systems

The concept of hybrids combining fuel cell and gas turbine systems is without question neoteric, and probably is less than eight years old. However, this concept is in a sense a logical development derived from the many early systems that embodied the key features of rotating machinery to compress air. It was the introduction of high temperature fuel cells such as the solid oxide fuel cell (SOFC) that allowed the concept of hybrid gas turbine fuel cell systems to take root. The SOFC with an operating temperature circa 1000° C matched well with small industrial gas turbines that had firing temperatures on the same order. The recognition that the SOFC could be substituted for the gas turbine combustor was the first step into the realm of fuel cell topping systems. Fuel cells in general were recognized as having higher efficiencies at elevated pressures. Thus the hybrid topping system where the gas turbine pressurized the fuel cell and the fuel cell supplied the hot gases for expansion over the turbine promised to provide a high level of synergy between the two systems. Bottoming systems using the exhaust of a gas turbine as the working fluid of a fuel cell such as the molten carbonate fuel cell (MCFC) have been identified and are potential future power generation hybrid systems. The MCFC is especially well suited to the bottoming role because of the need to have carbon dioxide present in the inlet air stream. The carbon dioxide in the gas turbine exhaust allows the high temperature blower, normally used to recirculate and inject exhaust products into the inlet air, to be eliminated. Hybrid systems have the potential of achieving fossil fuel to electricity conversion efficiencies on the order of 70% and higher. The costs of hybrid systems in dollars per kilowatt are generally higher than say an advanced gas turbine that is available today but not by much. The net energy output over the life of a hybrid topping system is similar to that of a recuperated gas turbine but possibly lower than a high-efficiency simple-cycle machine, depending on the efficiency of the hybrid. Methodologies to aid in the selection of the hybrid system for future development have to be developed and used consistently. Life cycle analyses (LFA) provide a framework for such selection processes. In particular the concept of net energy output provides a mechanism to assign relative worth to competing concepts.

Gas Turbine Cycles With Solid Oxide Fuel Cells—Part II: A Detailed Study of a Gas Turbine Cycle With an Integrated Internal Reforming Solid Oxide Fuel Cell

1994 ◽  
Vol 116 (4) ◽  
pp. 312-318 ◽  
Author(s):  
S. P. Harvey ◽  
H. J. Richter
Keyword(s):  
Power Generation ◽  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cells ◽  
Solid Oxide Fuel Cell ◽  
Energy Conversion ◽  
Gas Turbine ◽  
Solid Oxide ◽  
Oxide Fuel

In conventional energy conversion processes, the fuel combustion is usually highly irreversible, and is thus responsible for the low overall efficiency of the power generation process. The energy conversion efficiency can be improved if immediate contact of air and fuel is prevented. One means to prevent this immediate contact is the use of fuel cell technology. Significant research is currently being undertaken to develop fuel cells for large-scale power production. High-temperature solid oxide fuel cells (SOFC) have many features that make them attractive for utility and industrial applications. However, in view of their high operating temperatures and the incomplete nature of the fuel oxidation process, such fuel cells must be combined with conventional power generation technology to develop power plant configurations that are both functional and efficient. Most fuel cell cycles proposed in the literature use a high-temperature fuel cell running at ambient pressure and a steam bottoming cycle to recover the waste heat generated by the fuel cell. With such cycles, the inherent flexibility and shorter start-up time characteristics of the fuel cell are lost. In Part I of this paper (Harvey and Richter, 1994), a pressurized cycle using a solid oxide fuel cell and an integrated gas turbine bottoming cycle was presented. The cycle is simpler than most cycles with steam bottoming cycles and more suited to flexible power generation. In this paper, we will discuss this cycle in more detail, with an in-depth discussion of all cycle component characteristics and losses. In particular, we will make use of the fuel cell’s internal fuel reforming capability. The optimal cycle parameters were obtained based on calculations performed using Aspen Technology’s ASPEN PLUS process simulation software and a fuel cell simulator developed by Argonne National Laboratory (Ahmed et al., 1991). The efficiency of the proposed cycle is 68.1 percent. A preliminary economic assessment of the cycle shows that it should compare favorably with a state-of-the-art combined cycle plant on a cost per MWe basis.

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.

scholarly journals A proposed fuel cell vehicle for reducing CO2 emissions and its contribution to reducing greenhouse gas emissions

2014 ◽  
Vol 3 (2) ◽  
pp. 252 ◽  
Author(s):  
Mohamed Mourad
Keyword(s):  
Carbon Dioxide ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Co2 Emissions ◽  
Greenhouse Gas Emission ◽  
Fuel Cell Vehicle ◽  
Fuel Cell Vehicles ◽  
Gas Emissions

Because of their high efficiency and low emissions, fuel cell vehicles are undergoing extensive research and development. When considering the introduction of advanced vehicles, a complete evaluation must be performed to determine the potential impact of a technology on carbon dioxide (CO2) and greenhouse gases emissions. However, the reduction of CO2 emission from the vehicle became the most important objective for all researches institutes of vehicle technologies worldwide. There interest recently to find unconventional methods to reduce greenhouse gas emission from vehicle to keep the environment clean. This paper offers an overview and simulation study to fuel cell vehicles, with the aim of introducing their main advantages and evaluates their influence on emissions of carbon dioxide from fuel cell vehicle and compares advanced propulsion technologies on a well-to-wheel energy basis by using current technology for conventional and fuel cell. The results indicate that the use of fuel cells, and especially fuel cells that consume hydrogen, provide a good attempt for enhancing environment quality and reducing greenhouse gas (GHG) emissions. Moreover, the emission reduction percentage of fuel cell vehicle reaches to 64% comparing to the conventional vehicle. Keywords: Fuel Cell Electric Vehicle, Performance, Simulation, Driving Cycle, CO2 Emissions, Greenhouse Gas Emissions, Fuel Consumption.

The Thermodynamic Evaluation and Optimization of Fuel Cell Systems

2006 ◽  
Vol 3 (2) ◽  
pp. 155-164 ◽  
Author(s):  
N. Woudstra ◽  
T. P. van der Stelt ◽  
K. Hemmes
Keyword(s):  
Heat Transfer ◽  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Energy Conversion ◽  
System Optimization ◽  
Fuel Conversion ◽  
Cell Systems ◽  
Electrochemical Conversion ◽  
Conversion Efficiencies

Energy conversion today is subject to high thermodynamic losses. About 50% to 90% of the exergy of primary fuels is lost during conversion into power or heat. The fast increasing world energy demand makes a further increase of conversion efficiencies inevitable. The substantial thermodynamic losses (exergy losses of 20% to 30%) of thermal fuel conversion will limit future improvements of power plant efficiencies. Electrochemical conversion of fuel enables fuel conversion with minimum losses. Various fuel cell systems have been investigated at the Delft University of Technology during the past 20 years. It appeared that exergy analyses can be very helpful in understanding the extent and causes of thermodynamic losses in fuel cell systems. More than 50% of the losses in high temperature fuel cell (molten carbonate fuel cell and solid oxide fuel cell) systems can be caused by heat transfer. Therefore system optimization must focus on reducing the need for heat transfer as well as improving the conditions for the unavoidable heat transfer. Various options for reducing the need for heat transfer are discussed in this paper. High temperature fuel cells, eventually integrated into gas turbine processes, can replace the combustion process in future power plants. High temperature fuel cells will be necessary to obtain conversion efficiencies up to 80% in the case of large scale electricity production in the future. The introduction of fuel cells is considered to be a first step in the integration of electrochemical conversion in future energy conversion systems.

Optimization of a MCFC/Turbine Hybrid System for Cogeneration

2003 ◽  
Author(s):  
Georgia C. Karvountzi ◽  
Clifford M. Price ◽  
Paul F. Duby
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Hybrid System ◽  
Heat Balance ◽  
Gas Turbines ◽  
Cogeneration Plant ◽  
Hybrid Cycle

High temperature fuel cells can be integrated in a hybrid cycle with a gas turbine and achieve lower heating value (LHV) efficiencies of about 70%. A hybrid cycle designed for cogeneration applications could lead to even higher LHV efficiencies such as 78% to 80% without post combustion and 85%–90% with post combustion. The purpose of the present paper is to optimize the integration of a high temperature fuel cell in a cogeneration cycle. We used Gatecycle™ heat balance software by GE Enter Software, LLC, to design a 20–80 MW high efficiency cogeneration plant. Since Gatecycle™ does not have an icon for the fuel cell, we calculated the heat balance for the fuel cell stack in Microsoft® Excel and we imported the results into Gatecycle™. We considered a 8.5 MW, a 17 MW and a 34 MW fuel cell by scaling up of the commercially available 3MW molten carbonate fuel cell (MCFC). Our goal was to evaluate the optimum ratio between the fuel cell size and gas turbine size using a family of curves we developed showing LHV “electric” efficiency versus power for different ratios of “fuel cell–to–gas turbines size”. Similar curves showing LHV “cogeneration” efficiency are also presented. In addition configurations with a back pressure steam turbine and with a condensing steam turbine are evaluated. The influence of steam generation pressure in the overall system efficiency is discussed, as well as the performance of the hybrid system for different temperatures (0°F–80°F) and elevations (0 ft–3000 ft). Our conclusion is that high temperature fuel cells in a hybrid configuration with gas turbines could be successfully integrated into a cogeneration plant to achieve very high efficiencies.

Modeling of a Methane Fuelled Direct Carbon Fuel Cell System

2005 ◽  
Author(s):  
N. Woudstra ◽  
T. P. van der Stelt ◽  
K. Hemmes
Keyword(s):  
Heat Transfer ◽  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Energy Conversion ◽  
Fuel Conversion ◽  
Cell Systems ◽  
Electrochemical Conversion ◽  
Direct Carbon Fuel Cell ◽  
Conversion Efficiencies

Energy conversion today is subject to high thermodynamic losses. About 50 to 90 % of the exergy of primary fuels is lost during conversion into power or heat. The fast increasing world energy demand makes a further increase of conversion efficiencies inevitable. The substantial thermodynamic losses (exergy losses of 20 to 30 %) of thermal fuel conversion will limit future improvements of power plant efficiencies. Electrochemical conversion of fuel enables fuel conversion with minimum losses. Various fuel cell systems have been investigated at the Delft University of Technology during the past twenty years. It appeared that exergy analyses can be very helpful in understanding the extent and causes of thermodynamic losses in fuel cell systems. More than 50 % of the losses in high temperature fuel cell (MCFC and SOFC) systems can be caused by heat transfer. Therefore system optimisation must focus on reducing the need for heat transfer as well as improving the conditions for the unavoidable heat transfer. Various options for reducing the need for heat transfer are discussed in this paper. High temperature fuel cells, eventually integrated into gas turbine processes, can replace the combustion process in future power plants. High temperature fuel cells will be necessary to obtain conversion efficiencies up to 80 % in case of large scale electricity production in the future. The introduction of fuel cells is considered to be a first step in the integration of electrochemical conversion in future energy conversion systems.

Parametric Study of the Combined Fuel Cell-Gas Turbine Power Plant

2006 ◽  
Author(s):  
F. S. Bhinder ◽  
Munzer S. Y. Ebaid ◽  
Moh’d Yazid F. Mustafa ◽  
Raj K. Calay ◽  
Mohammed H. Kailani
Keyword(s):  
Power Generation ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Power Plant ◽  
Gas Turbine ◽  
Electrical Power Generation ◽  
Parametric Study ◽  
Large Scale ◽  
Electrical Power ◽  
Gas Turbine Power Plant

Large scale electrical power generation faces two serious problems: (i) energy conservation; and (ii) protection of the environment. High temperatures fuel cells have the potential to deal with both problems. The heat rejected by the fuel cell that would otherwise be wasted may be recovered to power a gas turbine in order to improve the energy conversion efficiency as well as power output of the combined fuel cell-gas turbine power plant. The added advantage of this approach would be to reduce thermal loading and the emission of greenhouse gases per MW electrical power generated. Serious research is being carried out worldwide to commercialise the fuel cell nevertheless there is still ample scope for studying the application of high temperature fuel cells in combination with the gas turbine for large scale electrical power generation. This paper presents the results of a parametric study of the fuel cell-gas turbine power plant to generate electricity. The paper should be of considerable interest to the designers and applications engineers working in power generation industry and other public utilities. The authors hope that the paper would lead to a stimulating discussion.

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