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Title: Combined Power Generation and Carbon Sequestration Using Direct FuelCell

Abstract

The unique chemistry of carbonate fuel cell offers an innovative approach for separation of carbon dioxide from greenhouse gases (GHG). The carbonate fuel cell system also produces electric power at high efficiency. The simultaneous generation of power and sequestration of greenhouse gases offer an attractive scenario for re-powering the existing coal-fueled power plants, in which the carbonate fuel cell would separate the carbon dioxide from the flue gas and would generate additional pollutant-free electric power. Development of this system is concurrent with emergence of Direct FuelCell{reg_sign} (DFC{reg_sign}) technology for generation of electric power from fossil fuels. DFC is based on carbonate fuel cell featuring internal reforming. This technology has been deployed in MW-scale power plants and is readily available as a manufactured product. This final report describes the results of the conceptualization study conducted to assess the DFC-based system concept for separation of CO2 from GHG. Design and development studies were focused on integration of the DFC systems with coal-based power plants, which emit large amounts of GHG. In parallel to the system design and simulation activities, operation of laboratory scale DFC verified the technical concept and provided input to the design activity. The system was studied to determine itsmore » effectiveness in capturing more than ninety percent of CO2 from the flue gases. Cost analysis was performed to estimate the change in cost of electricity for a 200 MW pulverized coal boiler steam cycle plant retrofitted with the DFC-based CO2 separation system producing an additional 127 MW of electric power. The cost increments as percentage of levelized cost of electricity were estimated for a range of separation plant installations per year and a range of natural gas cost. The parametric envelope meeting the goal (<20% increase in COE) was identified. Results of this feasibility study indicated that DFC-based separation systems have the potential for capturing at least 90% of the emissions from the greenhouse gases generated by power plants and other industrial exhaust streams, and yet entail in less than 20% increase in the cost of energy services for long-term deployment (beyond 2012). The anticipated cost of energy increase is in line with DOE's goal for post-combustion systems as outlined in the ''Carbon Capture and Sequestration Systems Analysis Guidelines'', published by NETL, April 2005. During the course of this study certain enabling technologies were identified and the needs for further research and development were discussed.« less

Authors:
Publication Date:
Research Org.:
FuelCell Energy, Inc.
Sponsoring Org.:
USDOE
OSTI Identifier:
886943
DOE Contract Number:
FC26-04NT42206
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; 29 ENERGY PLANNING, POLICY AND ECONOMY; 30 DIRECT ENERGY CONVERSION; CARBON; CARBON DIOXIDE; CARBON SEQUESTRATION; ELECTRIC POWER; FLUE GAS; FOSSIL FUELS; FUEL CELLS; GREENHOUSE GASES; NATURAL GAS; POWER GENERATION; POWER PLANTS; SYSTEMS ANALYSIS

Citation Formats

Hossein Ghezel-Ayagh. Combined Power Generation and Carbon Sequestration Using Direct FuelCell. United States: N. p., 2006. Web. doi:10.2172/886943.
Hossein Ghezel-Ayagh. Combined Power Generation and Carbon Sequestration Using Direct FuelCell. United States. doi:10.2172/886943.
Hossein Ghezel-Ayagh. Wed . "Combined Power Generation and Carbon Sequestration Using Direct FuelCell". United States. doi:10.2172/886943. https://www.osti.gov/servlets/purl/886943.
@article{osti_886943,
title = {Combined Power Generation and Carbon Sequestration Using Direct FuelCell},
author = {Hossein Ghezel-Ayagh},
abstractNote = {The unique chemistry of carbonate fuel cell offers an innovative approach for separation of carbon dioxide from greenhouse gases (GHG). The carbonate fuel cell system also produces electric power at high efficiency. The simultaneous generation of power and sequestration of greenhouse gases offer an attractive scenario for re-powering the existing coal-fueled power plants, in which the carbonate fuel cell would separate the carbon dioxide from the flue gas and would generate additional pollutant-free electric power. Development of this system is concurrent with emergence of Direct FuelCell{reg_sign} (DFC{reg_sign}) technology for generation of electric power from fossil fuels. DFC is based on carbonate fuel cell featuring internal reforming. This technology has been deployed in MW-scale power plants and is readily available as a manufactured product. This final report describes the results of the conceptualization study conducted to assess the DFC-based system concept for separation of CO2 from GHG. Design and development studies were focused on integration of the DFC systems with coal-based power plants, which emit large amounts of GHG. In parallel to the system design and simulation activities, operation of laboratory scale DFC verified the technical concept and provided input to the design activity. The system was studied to determine its effectiveness in capturing more than ninety percent of CO2 from the flue gases. Cost analysis was performed to estimate the change in cost of electricity for a 200 MW pulverized coal boiler steam cycle plant retrofitted with the DFC-based CO2 separation system producing an additional 127 MW of electric power. The cost increments as percentage of levelized cost of electricity were estimated for a range of separation plant installations per year and a range of natural gas cost. The parametric envelope meeting the goal (<20% increase in COE) was identified. Results of this feasibility study indicated that DFC-based separation systems have the potential for capturing at least 90% of the emissions from the greenhouse gases generated by power plants and other industrial exhaust streams, and yet entail in less than 20% increase in the cost of energy services for long-term deployment (beyond 2012). The anticipated cost of energy increase is in line with DOE's goal for post-combustion systems as outlined in the ''Carbon Capture and Sequestration Systems Analysis Guidelines'', published by NETL, April 2005. During the course of this study certain enabling technologies were identified and the needs for further research and development were discussed.},
doi = {10.2172/886943},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2006},
month = {Wed Mar 01 00:00:00 EST 2006}
}

Technical Report:

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  • This report summarizes the progress made in development of Direct FuelCell/Turbine{reg_sign} (DFC/T{reg_sign}) power plants for generation of clean power at very high efficiencies. The DFC/T power system is based on an indirectly heated gas turbine to supplement fuel cell generated power. The DFC/T power generation concept extends the high efficiency of the fuel cell by utilizing the fuel cell's byproduct heat in a Brayton cycle. Features of the DFC/T system include: electrical efficiencies of up to 75% on natural gas, 60% on coal gas, minimal emissions, simplicity in design, direct reforming internal to the fuel cell, reduced carbon dioxide releasemore » to the environment, and potential cost competitiveness with existing combined cycle power plants. Detailed design of the packaged sub-MW alpha DFC/T unit has been completed for mechanical and piping layouts and for structural drawings. Procurement activities continued with delivery of major equipment items. Fabrication of the packaged sub-MW alpha DFC/T unit has been initiated. Details of the process control philosophy were defined and control software programming was initiated.« less
  • This report includes the progress in development of Direct Fuel Cell/Turbine. (DFC/T.) power plants for generation of clean power at very high efficiencies. The DFC/T power system is based on an indirectly heated gas turbine to supplement fuel cell generated power. The DFC/T power generation concept extends the high efficiency of the fuel cell by utilizing the fuel cell's byproduct heat in a Brayton cycle. Features of the DFC/T system include: electrical efficiencies of up to 75% on natural gas, 60% on coal gas, minimal emissions, simplicity in design, direct reforming internal to the fuel cell, reduced carbon dioxide releasemore » to the environment, and potential cost competitiveness with existing combined cycle power plants. FCE successfully completed testing of the pre-alpha sub-MW DFC/T power plant. This power plant was constructed by integration of a 250kW fuel cell stack and a microturbine. Following these proof-of-concept tests, a stand-alone test of the microturbine verified the turbine power output expectations at an elevated (representative of the packaged unit condition) turbine inlet temperature. Preliminary design of the packaged sub-MW alpha DFC/T unit has been completed and procurement activity has been initiated. The preliminary design of a 40 MW power plant including the key equipment layout and the site plan was completed. A preliminary cost estimate for the 40 MW DFC/T plant has also been prepared. The tests of the cascaded fuel cell concept for achieving high fuel utilizations were completed. The tests demonstrated that the concept results in higher power plant efficiency. Alternate stack flow geometries for increased power output/fuel utilization capabilities are also being evaluated.« less
  • This report summarizes the progress made in development of Direct FuelCell/Turbine (DFC/T{reg_sign}) power plants for generation of clean power at very high efficiencies. The DFC/T system employs an indirectly heated Turbine Generator to supplement fuel cell generated power. The concept extends the high efficiency of the fuel cell by utilizing the fuel cell's byproduct heat in a Brayton cycle. Features of the DFC/T system include: electrical efficiencies of up to 75% on natural gas, minimal emissions, reduced carbon dioxide release to the environment, simplicity in design, direct reforming internal to the fuel cell, and potential cost competitiveness with existing combinedmore » cycle power plants. Proof-of-concept tests using a sub-MW-class DFC/T power plant at FuelCell Energy's (FCE) Danbury facility were conducted to validate the feasibility of the concept and to measure its potential for electric power production. A 400 kW-class power plant test facility was designed and retrofitted to conduct the tests. The initial series of tests involved integration of a full-size (250 kW) Direct FuelCell stack with a 30 kW Capstone microturbine. The operational aspects of the hybrid system in relation to the integration of the microturbine with the fuel cell, process flow and thermal balances, and control strategies for power cycling of the system, were investigated. A subsequent series of tests included operation of the sub-MW Direct FuelCell/Turbine power plant with a Capstone C60 microturbine. The C60 microturbine extended the range of operation of the hybrid power plant to higher current densities (higher power) than achieved in initial tests using the 30kW microturbine. The proof-of-concept test results confirmed the stability and controllability of operating a fullsize (250 kW) fuel cell stack in combination with a microturbine. Thermal management of the system was confirmed and power plant operation, using the microturbine as the only source of fresh air supply to the system, was demonstrated. System analyses of 40 MW DFC/T hybrid systems, approaching 75% efficiency on natural gas, were carried out using CHEMCAD simulation software. The analyses included systems for near-term and long-term deployment. A new concept was developed that was based on clusters of one-MW fuel cell modules as the building blocks. The preliminary design of a 40 MW power plant, including the key equipment layout and the site plan, was completed. The process information and operational data from the proof-of-concept tests were used in the design of 40 MW high efficiency DFC/T power plants. A preliminary cost estimate for the 40 MW DFC/T plant was also prepared. Pilot-scale tests of the cascaded fuel cell concept for achieving high fuel utilizations were conducted. The tests demonstrated that the concept has the potential to offer higher power plant efficiency. Alternate stack flow geometries for increased power output and fuel utilization capabilities were also evaluated. Detailed design of the packaged sub-MW DFC/T Alpha Unit was completed, including equipment and piping layouts, instrumentation, electrical, and structural drawings. The lessons learned from the proof-of-concept tests were incorporated in the design of the Alpha Unit. The sub-MW packaged unit was fabricated, including integration of the Direct FuelCell{reg_sign} (DFC{reg_sign}) stack module with the mechanical balance-of-plant and electrical balance-of-plant. Factory acceptance tests of the Alpha DFC/T power plant were conducted at Danbury, CT. The Alpha Unit achieved an unsurpassed electrical efficiency of 58% (LHV natural gas) during the factory tests. The resulting high efficiency in conversion of chemical energy to electricity far exceeded any sub-MW class power generation equipment presently in the market. After successful completion of the factory tests, the unit was shipped to the Billings Clinic in Billings, MT, for field demonstration tests. The DFC/T unit accomplished a major achievement by successfully completing 8000 hours of operation at the Billings site. The Alpha sub-MW DFC/T power plant unit was returned to the factory for post-operation inspection and analysis. The success of the Alpha Unit operation in the field and achievement of the ultra-high efficiency of 58%, triggered the establishment of a MW-scale commercial product design and development program. Design of a 3 MW (nominal rating) DFC/T Power Plant was completed with an electrical efficiency approaching 60+% LHV of natural gas depending on the design and performance of the gas turbine. Development efforts incorporated lessons learned from the Alpha sub-MW DFC/T power plant demonstration, as well as design features from FCE's commercial product offerings, the DFC1500 and DFC3000 MW-class simple cycle power plants. The 3 MW DFC/T power plant is anticipated to be a superb alternative for large distributed generation applications in locations with high cost-of-electricity.« less
  • Soil emissions have been inadequately characterized in life cycle assessment of biofuels (see section 3.2.3). This project measures the net differences in field-level greenhouse gas emissions (CO 2, N 2O, and CH 4) due to corn residue removal for cellulosic ethanol production. Gas measurements are then incorporated into life cycle assessment of the final biofuel product to determine whether it is in compliance with federal greenhouse gas emissions standards for biofuels (Renewable Fuel Standard 2, RFS2). The field measurements have been conducted over three years on two, quarter-section, production-scale, irrigated corn fields (both roughly 50 hectares, as this size ofmore » field is necessary for reproducible eddy covariance flux measurements of CO 2; chamber measurements are used to determine N 2O and CH 4 emissions). Due to a large hail storm in 2010, estimates of the emission from residue could not be separated from the total CO 2 flux in 2011. This led us to develop soil organic carbon (SOC) modeling techniques to estimate changes in CO 2 emissions from residue removal. Modeling has predicted emissions of CO 2 from oxidation of SOC that are consistent (<12%) with 9 years of CO 2 flux measurements at the two production field sites, and modeling is also consistent with other field measurements (Liska et al., submitted). The model was then used to estimate the average change in SOC and CO 2 emissions from nine years of simulated residue removal (6 Mg biomass per hectare per year) at the sites; a loss of 0.43 Mg C ha -1 yr -1 resulted. The model was then used to estimate SOC changes over 10 years across Nebraska using supercomputing, based on 61 million, 30 x 30 meter, grid cells to account for regional variability in initial SOC, crop yield, and temperature; an average loss of 0.47 Mg C ha -1 yr -1 resulted. When these CO 2 emissions are included in simple life cycle assessment calculations, emissions from cellulosic ethanol from crop residue are above mandated levels of 60% reduction compared to gasoline (Liska, in press). These approaches are both technically effective and economically feasible. This work has been extensively peer reviewed.« less
  • Small-scale experimental work at Lawrence Livermore National Laboratory (LLNL) has confirmed that a direct carbon fuel cell (DCFC) containing a molten carbonate electrolyte completely reacts solid elemental carbon with atmospheric oxygen contained in ambient air at a temperature of 650-800 C. The efficiency of conversion of the chemical energy in the fuel to DC electricity is 75-80% and is a result of zero entropy change for this reaction and the fixed chemical potentials of C and CO{sub 2}. This is about twice as efficient as other forms power production processes that utilize solid fuels such as petroleum coke or coal.more » These range from 30-40% for coal fired conventional subcritical or supercritical boilers to 38-42% for IGCC plants. A wide range of carbon-rich solids including activated carbons derived from natural gas, petroleum coke, raw coal, and deeply de-ashed coal have been evaluated with similar conversion results. The rate of electricity production has been shown to correlate with disorder in the carbon structure. This report provides a preliminary independent assessment of the economic potential of DCFC for competitive power generation. This assessment was conducted as part of a Director's Research Committee Review of DCFC held at Lawrence Livermore National Laboratory (LLNL) on April 9, 2004. The key question that this assessment addresses is whether this technology, which appears to be very promising from a scientific standpoint, has the potential to be successfully scaled up to a system that can compete with currently available power generation systems that serve existing electricity markets. These markets span a wide spectrum in terms of the amount of power to be delivered and the competitive cost in that market. For example, DCFC technology can be used for the personal power market where the current competition for delivery of kilowatts of electricity is storage batteries, for the distributed generation market where the competition for on-site power generation in the range of 0.5 to 50 MW is small engines fueled with natural gas or liquid fuels or in the bulk power markets supplied usually by remote central station power plants with capacities of 250-1250 MW that deliver electricity to customers via the transmission and distribution grid. New power generation technology must be able to offer a significant cost advantage over existing technologies serving the same market to attract the interest of investors that are needed to provide funding for the development, demonstration, and commercialization of the technology. That path is both lengthy and expensive. One of the key drivers for any new power generation technology is the relative amount of pollutant emissions of all types, particularly those that are currently regulated or may soon be regulated. The new focus on greenhouse gas emissions offers a window of opportunity to DCFC technology because of its much higher conversion efficiency and the production of a very concentrated stream of CO{sub 2} in the product gas. This should offer a major competitive advantage if CO{sub 2} emissions are constrained by regulation in the future. The cost of CO{sub 2} capture, liquefaction, and pressurization has the potential to be much less costly with DCFC technology compared to other currently available forms of fossil fuel power generation.« less