Review of DOE's Vision 21 Research and Development Program Phase I (2003) / Chapter Skim
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3. Vision 21 Technologies
3. Vision 21 Technologies
Pages 24-85
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From page 24... ...
Further detail and background on the technologies can be found in the committee's 2000 report, in the Vision 21 Program Plan and in the Vision 21 Technology Roadmap (NRC, 2000; DOE, 1999a; NETL, 2001~. GASIFICATION Introduction Fuel-flexible gasification systems convert carbon-containing feedstocks (coal, petroleum coke, residual oil, wastes, biomass, etc.)
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From page 25... ...
, fuel cells, or gas turbine plus fuel cell hybrid power plants at high energy conversion efficiencies. These are the most likely combinations of coal-conversion technology and energyconversion technology with the potential to achieve the 60 percent higher heating value (HHV)
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From page 26... ...
Improvements in all five sections of the IGCC plant feed solids handling, air separation, gasification, gas cleanup, and power generation will be necessary. Milestones and Goals The current goals of the gasification program are as follows: · Fuel flexibility up to 10 percent (large units)
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· A design optimization study has indicated that capital cost reductions of 20 percent and a reduction in the overall IGCC commercial plant project timetable (design and construction) from 57 months to 46 months are possible.
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program, which is described as follows by DOE (2002b) : The CCPI is a cost-shared partnership between the government and industry to demonstrate advanced coal-based, power generation technologies.
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R&D programs have been initiated that relate to the gasification section, oxygen production, hydrogen separation, CO2 capture, and high-temperature fuel cells. Issues of Concern and Remaining Barriers Broad market acceptance of coal gasification as measured by a significant number of new orders for gasification-based power plants in the years after 2015 will require commercial-scale experience to provide the appropriate design bases that can be replicated.
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From page 30... ...
plants, as well as gasification plants for the production of hydrogen and other chemical feedstocks, are economically viable today because the feedstocks for these plants have near-zero or negative value. However, commercial-scale coal-gasification-based power plants are not currently competitive with natural gas combined-cycle power plants at today's relative natural gas and coal prices, nor are they projected to be so by 2015 without significant capital cost reductions.
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From page 31... ...
The U.S. Department of Energy development programs for Vision 21 technologies for gas cleanup, fuel cells, and power production with advanced gas turbines do not currently include adequate testing of these technologies on actual coal-derived synthesis gas (syngas)
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From page 32... ...
Milestones and Goals The objectives of the Vision 21 gas purification program are these. .3 · Near-zero environmental emissions from gasification-based processes and · Reduce synthesis gas contaminant levels to protect downstream components Mid-temperature operation (300°-700°F)
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From page 33... ...
, the guiding principles and mechanism by which regeneration occurs completely and with high energy efficiency need to be carefully examined before significant outlays for additional research. NETL research activities have also led to a selective H2S oxidation process, which could bring significant reductions in the costs associated with synthesis gas cleanup.
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From page 34... ...
Less visible in the current program is any closer integration with science-based initiatives within and outside DOE or any attempt at the rational or theory-guided design of materials, which were included as general recommendations in the earlier committee report. Issues of Concern and Remaining Barriers Several issues are apparent from the emerging gas purification programs.
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From page 35... ...
These activities should be more closely connected to those sponsored by the gas separations, materials, and environmental controls subprograms in Vision 21 and possibly include a consolidation of these three subprograms into a single one with a more fundamental emphasis on the extraction of specific molecules from complex streams at medium temperatures. Recommendation.
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From page 36... ...
streams are required for power generation using fuel cells, and the availability of such streams will require significant advances in the extraction of H2 from the synthesis gas streams produced in coal and biomass gasification. The current program focuses narrowly on ceramic and metal-ceramic composite membranes, which, if successfully developed and implemented, will make it possible to generate pure O2 and H2 streams.
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From page 37... ...
Test a prototype air separation module integrated with a gas turbine (2006~; Develop a technology base for commercial hydrogen separation membranes (2006~; · First commercial membrane oxygen separation plants (2008~; and First commercial membrane hydrogen plants for power and fuels processing (2010~. No intermediate or more detailed milestones are stated,8 nor is it clear which of the several concurrent programs is supposed to achieve each of these milestones.
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From page 38... ...
They arise predominately from the untested large-scale implementation of ceramic membranes and from the high level and great variety of impurities in H2/CO2/CO streams derived from synthesis gas. Response to Recommendations from the Committee's 2000 Report The 2000 committee report recommended the rapid evaluation of the CO2 hydrate approach in anticipation of a greater emphasis on CO2 removal from shifted synthesis gas streams: The current program reflects changes in response to this recommendation (NRC, 2000~.
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From page 39... ...
The H2 ceramic membrane project appears to be too narrowly focused and to duplicate some of the efforts already made in solving related problems for ceramic materials, and the configurations useful for O2 transport are similar in composition, module design, and transport mechanism to those used for H2 transport. In both O2 and H2 ceramic membranes, the variable concentration and identity of the many impurities in process streams continue to raise significant concerns about the durability of these membrane systems, especially the H2 membranes, which must operate at higher temperatures and under more aggressive chemical environments, or when O2 transport membranes are more closely coupled to the gasifies in an effort to exploit chemical potential gradients to increase O2 fluxes and decrease compression costs.
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From page 40... ...
The two concurrent programs in O2 separations duplicate efforts with few synergies, and they seem ill advised at this stage of development and in light of the unmet demand for effort in other areas. The programmatic connections between the Vision 21 Program using pressure-driven O2 separation and parallel development efforts using concentration gradients in synthesis gas generation from natural gas are unclear; yet, materials, mechanical and chemical issues, and manufacturing technologies are nearly identical in the two approaches.
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From page 41... ...
Finding. The gasification-based emphasis in Vision 21 has created intellectual and technological connections among the areas currently structured as gas purification, gas separations, and environmental controls.
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From page 42... ...
FUEL CELLS Introduction Fuel cells convert the chemical energy in a fuel directly to electrical energy at high efficiency. High-temperature fuel cells, including molten carbonate and solid oxide systems, are capable of using mixtures of hydrogen, carbon monoxide, and methane as fuel.
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The current program calls for work to be carried out by established developers of high-temperature fuel cells. FuelCell Energy is working on molten carbonate, and Siemens-Westinghouse on solid oxide fuel cell systems.
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From page 44... ...
Progress, Significant Accomplishments, and Current Status The DOE/NETL continuing program in fuel cells recently fabricated and demonstrated two approximately 250-kW, natural-gas-fired, hybrid fuel cell-gas turbine power generation plants, one employing molten carbonate cells, the other solid oxide cells. The efficiencies of these systems, about 53 percent (LHV)
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From page 45... ...
Four current fuel cell projects are listed by DOE/NETL in the current Vision 21 Program: . · The design and cost estimate for a 40-MW hybrid molten carbonate fuel cell power system; An investigation of a system combining a solid oxide fuel cell power system with a ceramic membrane O2 transport system used to complete the combustion of the spent fuel, avoiding dilution of the CO2 product with N2; CO2 capture is thus simplified; The development and fabrication of a 3- to 5-kW planar solid oxide fuel cell system coupled with a supercharger-derived gas turbine.
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From page 46... ...
Suitable gas turbines could not be identified for a 1.0-MW tubular solid oxide fuel cell power system in an Environmental Protection Agency (EPA) laboratory building.
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From page 47... ...
The Vision 21 fuel cell program has initiated a project at the National Fuel Cell Research Center (NFCRC) to model and optimize the various natural-gasand coal-fired power system configurations, most of which incorporate solid oxide fuel cells.
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From page 48... ...
, and the DOE presentation to the committees This presentation identified the construction and operation of four demonstration plants as the major milestones of the program: A hybrid fuel cell-gas turbine power plant of about 1 MW (2006) , A fuel cell power plant integrated with a coal gas fuel processor (2006)
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From page 49... ...
It has focused on high-temperature molten carbonate and solid oxide fuel cells and on a single developer of each of these cell types. Both developers have successfully demonstrated natural-gasfueled power systems, both fuel cell based and hybrid fuel cell/gas turbine based, of 200 kW or larger.
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From page 50... ...
Response to Recommendations from the Committee's 2000 Report The following comments pertain to the DOE/NETL response to the recommendations on the fuel cell program from the committee's 2000 report on the Vision 21 program (NRC, 2000~. Essentially, the two recommendations from the 2000 report can be summarized as follows: The Vision 21 fuel cell program should focus on reducing the capital costs and enhancing the performance of fuel cell systems in large-scale power generation (or cogeneration)
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From page 51... ...
Finding. To meet efficiency and cost goals, Vision 21 utility-scale, coal-fired fuel cell power plants will require the integration of the fuel cells with coal gasification, fuel gas cleaning, and heat removal and recovery systems that produce additional electrical energy either through a gas turbine operating in a regenerative Brayton cycle or a steam generator and steam turbine operating in a Rankine cycle.
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From page 52... ...
The DOE/NETL fuel cell program has produced two hybrid fuel cellgas turbine power systems of approximately 250 kW, one based on molten carbonate and the other on solid oxide fuel cells. Three, possibly four, additional hybrid systems are included in the program plan and schedule.
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From page 53... ...
The U.S. Department of Energy National Energy Technology Laboratory Vision 21 fuel cell program plan and schedule should incorporate milestones in addition to the current four milestones, each of which represents the construction and operation of a high-temperature fuel cell power generation plant.
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From page 54... ...
These units generally are based on mid-199Os technologies with 2500°F firing temperatures and gross power outputs of 300-400 MW. Combined-cycle power plants will be the power generation technology of choice in early gasificationbased Vision 21 plants and may be used in conjunction with fuel cells in later gasification-based Vision 21 plants.
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From page 55... ...
It should be noted that neither the gas turbines nor the fuel cells used in
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Hybrid systems are discussed in more detail in the section of this chapter that addresses fuel cells. · Programs are under way to develop improved materials and manufacturing technologies for turbine blades.
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From page 57... ...
Hybrid gas turbine plants are being developed at this time for natural gas. There is likely to be a considerable amount of design and development work that must be done to optimally integrate a unit of this type into a gasification-based power plant.
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From page 58... ...
In response to current industry needs, the DOE High Efficiency Engine Technology (MEET) program is focused on natural gas as a fuel to both gas turbines and gas turbine-fuel cell hybrids.
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From page 59... ...
System studies should be used to determine if the use of oxygen and hydrogen in a turbine to reduce NOx emissions is economically viable. ENVIRONMENTAL CONTROL TECHNOLOGY Introduction The primary aim of the Vision 21 Program is elimination of environmental impacts from the use of coal to produce electricity, fuels, and chemicals.
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From page 60... ...
By December 2002 Phase I field testing of sorbent injection technology will be completed at four commercial coal-fired power plants to achieve 50-70 percent mercury (Hg) control.
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From page 61... ...
Under the program, a first-of-a-kind field testing of Hg control using sorbent injection achieved over 70 percent Hg removal. Such field tests provide a basic understanding of the operating parameters that affect sorbent performance and should support the development of novel approaches for control of Hg and other hazardous air emissions from Vision 21 gasification plants.
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From page 62... ...
Gas purification and environmental control for a Vision 21 plant are inherently intertwined. Near-zero emission levels from a Vision 21 plant may be desirable from one or both of the following standpoints: making the syngas an acceptable fuel for a gas turbine or fuel cell or meeting an environmental standard.
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From page 63... ...
In some cases, new generations of sensors and controls will be needed before an enabling technology can be implemented for example, several controls will be needed for the operation of hydrogen-fed gas turbines and fuel cells. Currently, there are seven sensors and controls projects related to the Vision 21 Program.
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From page 64... ...
Progress, Significant Accomplishments, and Current Status The workshop held in April 2001 provided good inputs for a list of needs for various Vision 21 enabling technologies, and a solicitation (de-ps26-02nt41432-3) for industry procurement related to sensors and controls sciences was released in 2002.
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From page 65... ...
The lists do not include enhancement of the enabling technologies, such as hydrogen-fed gas turbines, fuel cells, and gasification. The current R&D programs for sensors and controls lack inputs and participation from key stakeholders in the gasification demonstration plants and developers of Vision 21 enabling technologies.
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From page 66... ...
More slipstream demonstration projects should be implemented in existing gasification demonstration plants. MATERIALS Introduction The commercial viability of Vision 21 technologies will be highly dependent on the development of cost-effective advanced materials for oxygen separation membranes, gasifiers, high-temperature heat exchangers, high-temperature refractory, hydrogen separation membranes, seals and electrodes for fuel cells, thermal barrier coatings, blades and gas flow path for turbines, and ultra-high-temperature and high-pressure materials for advanced power generation.
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From page 67... ...
Develop and apply functional materials, including alloys and ceramics, for use as gas filters to remove particulates to levels required for gas turbines and other sensitive equipment; gas separation membranes; catalysts for fuel synthesis and other reactions; and fuel cell electrodes. The major milestones for the technologies for Vision 21 are as follows: · Test structural ceramics composites for turbines combustors (2005~.
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From page 68... ...
Weld-overlay techniques for intermetallics work is ongoing, with completion in 2004; · Extended lifetime metallic coatings completion in 2005; · Slurry-based mullite coating completion in mid-2006; · Metallic coatings for power generation completion in 2007; and · Corrosion protection at ultra-high temperatures completion in 2009. Work is under way in weld-overlay techniques for intermetallics.
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From page 69... ...
An ODS variant of this filter could achieve use temperatures of greater than 1000°C; Progress in developing reliable high-temperature seals associated with the use of solid-state electrolytes in fuel cells. This involves the development of oxidant-resistant brazes for joints in devices using solid-state electrolytes; Progress in developing a state-of-the-art technique for thin-film processing (including sintering)
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From page 70... ...
The main finding in the materials section was that the commercial success of the Vision 21 Program will depend largely on the successful development and demonstration of cost-effective coatings and structural materials, membranes, ceramics, and catalytic materials for Vision 21 systems and components. The recommendation for this finding was that the materials program should be based on the cost and performance goals for Vision 21 technologies and should be coordinated to meet those goals.
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From page 71... ...
Although this was an excellent first step and significant progress appears to have been made, the materials roadmap needs to incorporate intermediate milestones that would identify the actual time frames for selection of the specific cost-effective materials that are needed for the following: Oxygen separation membranes, Gasifiers, High-temperature heat exchangers, High-temperature refractory for gasifiers, Hydrogen separation membranes, Seals and electrodes for fuel cells, Thermal barrier coatings, and Blades and gas flow paths for gas turbines. Since the committee's last review (made in connection with the 2000 report)
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From page 72... ...
NSF and DOE's Basic Energy Sciences (BES) have programs that address a wide variety of fundamental materials research, but to date there is no connection with NETL' s Advanced Materials Program.
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From page 73... ...
The objectives of the Vision 21 simulation and modeling activity are as follows: · Develop science-based computational tools and apply them to simulate clean, highly efficient energy plants of the future; · Develop a virtual simulation capability that predicts: Interactions of turbines, fuel cells, combustors, environmental control systems and other major components; Dynamic responses of an entire energy plant; and A virtual environment in which to visit and explore future Vision 21 plants. The objectives of the Vision 21 systems analysis activity are as following: · Identify and evaluate concepts for Vision 21 plant subsystems and components; · Select "reference" plants for detailed study; and · Identify technology gaps and an R&D strategy to fill gaps.
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Current Status and Significant Accomplishments There have been several important accomplishments in simulation and modeling activities since the beginning of the Vision 21 Program. The National Fuel Cell Research Center (NFCRC)
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Recommendation. The Vision 21 Program Plan should be modified to address the need for a hierarchy of models suitable for preliminary design and scoping studies, as well as for detailed final designs.
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From page 76... ...
In the case of Vision 21, the problem is compounded by the fact that the plants will be complex systems that include many new technologies developed and implemented by different industries (e.g., power production, chemical production, fuel cells, carbon sequestration)
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From page 77... ...
For example, in most membrane processes the mass flux through the membrane and the installed cost of the membrane are critical issues to be addressed early in the R&D plan. In fuel cells, scale-up and membrane assembly cost are critical; in separations, mass flux per unit cross-sectional area; in reactors, catalyst productivity and also mass flux per area; and so forth.
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From page 78... ...
Based on this finding, the committee believes the focus should be on developing an engineering modeling team that is integrated directly with the Vision 21 management to provide engineering analysis and research guidance. This team can provide an independent perspective within the project on the value of various technologies in the context of Vision 21 schemes as well as on the probability of successful development.
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From page 79... ...
The main reasons are the higher cost of making syngas from coal than from natural gas and the lower molar ratio (<1.0) of hydrogen to carbon monoxide produced in coal gasifiers.
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From page 80... ...
The Proceedings of the Sixth Natural Gas Conversion Symposium, published by Elsevier, capture the breath and depth of the effort under way (Elsevier, 2001~. Previous symposia whose proceedings were also published by Elsevier, give an excellent retrospective on the evolution of this technology (Elsevier, 1997, 1998~.
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From page 81... ...
· A Consortium of Fossil Fuel Science was established with the objective of reducing the cost of synthesis gas conversion to products. Research is under way on supercritical F-T synthesis, new catalysts for the conversion of methanol to ethylene and propylene, and nanoscale iron catalysts for the conversion of methane to hydrogen, and carbon nanotubes.
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From page 82... ...
. It is important to note that even with inexpensive natural gas as the feed, syngas conversion plants are at best marginally competitive with fuels from crude oil.
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From page 83... ...
ADVANCED COAL COMBUSTION Introduction The Advanced Combustion Technologies Program is a very important component of the Office of Fossil Energy R&D program. It offers a near-term technological solution to improving efficiency and environmental performance in existing fossil-fuel power plant units, especially coal-fired power plants, and new units that may need to be constructed before Vision 21 systems are available or if Vision 21 systems prove unable to achieve the desired levels of performance and costs.
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From page 84... ...
efficiency and better environmental performance and lower cost than other combustion systems. Response to Recommendations from the Committee's 2000 Report In 2000, the committee found that the advanced combustion technologies in the Office of Fossil Energy's core power generation program were limited by practical engineering to efficiencies of 45 to 50 percent, which are substantially below Vision 21 Program goals of 60 percent (NRC, 2000~.
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From page 85... ...
The advanced combustion technologies have the potential to significantly improve efficiency and environmental performance over today's electric generating technologies and can enable the upgrading of the existing fleet of power plants or the construction of new plants. The advanced combustion technologies can also serve as a fallback alternative if the Vision 21 goals prove unobtainable technically or economically.
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