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Prepared Witness Testimony The House Committee on Energy and Commerce
Future Options for Generation of Electricity from Coal.
Subcommittee on Energy and Air Quality
Mr. Larry E. McDonald
TESTIMONY TO THE SUBCOMMITTEE ON ENERGY AND AIR QUALITY HOUSE ENERGY AND COMMERCE COMMITTEE FROM BABCOCK AND WILCOX COMPANY Presented by: Mr. Lawrence E. McDonald Director, Design Engineering and Technology Babcock & Wilcox Company 20 South Van Buren Ave Barberton, OH 44203 June 24, 2003 Chairman Barton, Ranking Member Boucher, and members of the subcommittee; Babcock & Wilcox Company is pleased to have the opportunity to provide testimony for the hearing of the Energy and Commerce Subcommittee on Energy and Air Quality on "Future Options for Generation of Electricity from Coal". Our testimony is primarily focused on the need for and potential benefits of an advanced combustion development program as an important dimension of our nation's approach to its energy future. Babcock & Wilcox Company is an operating unit of McDermott International. McDermott International, Inc. is a leading worldwide energy services company, providing engineering, fabrication, installation, procurement, research, manufacturing, environmental systems, and project management for a variety of customers in the energy and power industries, including the U.S. Department of Energy. For over 135 years, the Babcock & Wilcox Company has earned a reputation of excellence, setting the standards for the power generation industry and supplying innovative solutions to meet the world's growing energy needs. With power generation systems and equipment found in more than 800 utilities and industries in over 90 countries, we are truly powering the world. More than 10,800 employees around the globe make up the B&W team. And because of our forward-thinking, talented and dedicated employees, we continue to reach new levels of success. Summary A primary technical impediment to sequestration of exhaust gases from conventional coal-fired power plants is the dilution of the flue gases by the nitrogen that is contained in the combustion air that is supplied to the boilers. Air is about 21 percent oxygen, which is needed for combustion of the coal, and about 78 percent nitrogen. Development efforts are envisioned and/or underway by boiler technology suppliers to define practicable ways to create, through advanced combustion systems, concentrated streams of carbon dioxide from flue gases - thus facilitating subsequent sequestration if/when needed to respond to public policy imperatives. Babcock & Wilcox Company is exploring a variety of alternatives to produce concentrated streams of carbon dioxide from coal combustion systems; and is most actively engaged in oxy-fuel boiler system development. Through studies and pilot scale tests conducted to date, we are encouraged that the oxy-fuel system will be ready for large scale demonstration around year 2008. Assuming success, the concept would benefit new power plants and potentially have some application to the fleet of existing power plants. The U.S. economy will be favorably served by maintaining a variety of energy supply options. The government's coal power plans for the future are predominantly based on the presumption that gasification approaches will be the most viable options. It is possible that many of the gasification-related RD&D initiatives, such as FutureGen, will prove to be valuable. On the other hand, the variety of attributes of oxy-fuel combustion and other coal combustion based approaches leads us to anticipate greater potential marketplace viability for advanced combustion technologies. Advantages of some of the advanced combustion systems, exemplified by oxy-fuel combustion, include potential applicability to the existing fleet as well as new plants, near- to mid-term availability, relative simplicity of overall system designs, lower costs for capture of carbon dioxide, and comparable electricity generation efficiencies to gasification systems. Government support is warranted for the creation and funding of a substantial development and demonstration program in advanced combustion systems. General Comments U.S. economic growth depends upon low cost plentiful supplies of energy, which can best be achieved through an energy marketplace with a variety of responsible options. Coal will continue to be a major part of the energy supply mix for many decades to come. It makes up 90 percent of our domestic energy reserve, and 90 percent of the coal mined is used to generate approximately 50 percent of the electricity used in the country today. We are gratified that there is a growing recognition that coal will continue to be a major fuel source for our nation's electrical generation for the foreseeable future. Energy policies are likely to be affected by increasing priorities on carbon management. The challenges of natural gas availability, reserve depletion, prices, and price volatility are well known. Policies that encourage fuel switching to natural gas from the higher carbon content coal for generation may not be in the best interest of our country. The development and commercial use of clean coal technologies will enable the responsible use of coal; addressing priority pollutants and, coupled with sequestration, greenhouse gas emissions. Timely advances in clean coal technology will require significant cost-shared funding for research and development projects and demonstrations of emerging technology, and tax incentives to reduce the risks and encourage early deployment and refinement of the new technologies. These issues are addressed by industry groups such as the Coal Utilization Research Council and Electric Power Research Institute. Regarding carbon management technologies, until recently, approaches to carbon dioxide reductions in coal fired electrical power generation have been mainly focused on efficiency improvements; i.e., producing more electricity from each unit of coal burned, through development of advanced steam cycles with higher operating pressures and temperatures, improved operating controls, etc. This important cross-cutting work needs to continue. Much of the focus of government funded R&D for the future utilization of coal is weighted toward gasification. A principal attribute associated with integrated gasification combined cycle is the ability of the system to produce a concentrated stream of carbon dioxide, thus enabling sequestration. Gasification offers considerable potential, however, there are significant technological and economic hurdles that must be overcome in order to realize the benefits of these complex systems. Currently, power generation technology providers, especially boiler manufacturers, are focusing on developing advanced combustion approaches that would also produce concentrated streams of carbon dioxide potentially amenable to sequestration. The efforts to develop combustion alternatives to gasification create a dynamic scene; some of the advanced combustion systems are being defined and still others are emerging. Babcock & Wilcox is actively engaged in advanced combustion approaches which we are cautiously optimistic will prove to be viable options for concentration and capture of carbon dioxide in the near to mid term future. Some of the approaches should potentially be applicable to some of the existing power generation fleet as well as new facilities. The Coal Utilization Research Council, through its road-mapping process has determined that an Advanced Combustion Program needs to be an important part of the DOE's fossil energy R&D program. This has been conveyed to Congress and to the DOE. It is imperative that a suite of technologies be developed and that the marketplace be allowed to decide which are best suited based on site and economic conditions. We offer the following comments on the major planned demonstration programs, namely the Clean Coal Power Initiative and FutureGen. The Clean Coal Power Initiative provides appropriate opportunities for large-scale, first-of-a-kind demonstrations of new technologies. CCPI program rules should enable demonstration of a wide range of technological approaches. Future CCPI solicitations should not be arbitrarily weighted toward gasification, essentially impeding demonstrations of other responsible options. FutureGen is intended to be a major showcase and testbed for the combination of coal-based electricity generation, hydrogen production, and carbon dioxide sequestration. These are laudable goals. The planned $800 million government cost share for the projected $1 billion total project cost is a large commitment in an environment of severe budget constraints. By way of comparison, the entire CCPI demonstration program will require $2 billion in government cost shares over its entire 10-year duration, presuming full funding. It is critical that funding for FutureGen be provided as additions to the DOE budget; and not by reducing or redirecting funds otherwise intended to support CCPI or the other important clean coal research, development, and demonstration programs. Ultimately, the marketplace will decide the technologies that are utilized, and we repeat that our country's interests will be best served by providing many different responsible options. As the National Coal Council stated in its May 2003 report "Research And Development Needs And Deployment Issues For Coal Related Greenhouse Gas Management", ".Given the time before wide-scale sequestration is likely to be practiced, there is an opportunity to explore a wide range of potential capture options, applicable to both gasification and combustion systems, in the hope that break-through technology can be identified to reduce the onerous costs and energy penalties of current approaches." Oxygen Combustion In a conventional power plant, coal is burned with air to produce heat and generate steam that is converted to electricity by a turbine-generator. The flue gas streams are, as a result, diluted with large quantities of nitrogen from the combustion air. Air contains 78% nitrogen; only the oxygen in the air is used to convert the fuel to heat energy. Prior to the last few years, conventional wisdom was that practicable carbon dioxide separation was not attainable in conventional coal fired plant designs. Currently, the domestic boiler suppliers are active in advanced combustion systems research aimed at carbon management. Combustion of coal with oxygen rather than air is one of the promising approaches. Oxy-fuel combustion is the approach that Babcock & Wilcox is most actively pursuing - the approach that we believe is closest to commercialization. Progress in B&W's Oxy-Fuel Combustion Program In the oxygen-fuel fired boiler concept, combustion air is replaced with relatively pure oxygen. The oxygen is supplied by an on-site air separation unit, with nitrogen and argon being produced as byproducts of the oxygen production. For the oxy-fuel boiler system, a portion of the flue gas is returned back to the burners, and the nitrogen that would normally be conveyed with the air through conventional air-fuel firing is essentially replaced by carbon dioxide. This results in the creation of a flue gas that is primarily a concentrated stream of carbon dioxide, rather than nitrogen, and other products of coal combustion. The volume of carbon dioxide-rich flue gas leaving the plant is about one fourth of that of a conventional air-fired plant. This concentrated stream of carbon dioxide would then be available for subsequent sequestration. Figure 1 schematically compares a modern conventional plant, Figure 1A, to an oxy-fuel power plant, Figure 1B.
Figure 1A. Conventional modern air-fuel fired power plant
Figure 1B. Oxy-fuel fired power plant In 1999 Babcock & Wilcox joined an international consortium consisting of utilities, industrial gas companies, and a research & development organization, to sponsor oxy-fuel combustion in a bench-scale combustor at CANMET. The bench-scale work showed that concentration of carbon dioxide is feasible. Some of the developmental issues could not be addressed at the small bench-scale facility, e.g., equipment for introduction of oxygen into the burner, potential need for boiler heat transfer surface modification, etc. Additionally, we are conducting a U.S. DOE-sponsored review entitled "Evaluation of Oxygen Enriched Combustion Technology for Enhanced CO2 Recovery." A larger 5MBTU/HR proof-of-concept pilot-scale evaluation of the technology is being performed at the Babcock & Wilcox Research Center in a facility known as the Small Boiler Simulator (SBS) that simulates full-scale coal-fired boilers. The SBS has recently been modified for the oxygen-firing of coal with recycled flue gas under a program sponsored by the State of Illinois. Partial substitution of combustion air (up to 80%) with oxygen-enriched flue gas has been demonstrated and plans are in place to replace all of the combustion air with oxygen this year. A layout of the modified SBS facility appears in Figure 2. Figure 2 - SBS Oxygen-Firing Configuration
In addition to pilot scale testing, B&W has been working on initial studies to evaluate the application of oxy-fuel conversion of existing plants firing different coals as well as the impact on the design of a new oxy-fuel plant with a high efficiency state-of-the-art steam cycle. These studies have provided significant insights into the impact of equipment arrangement options and oxygen and carbon dioxide purity on both performance and cost; and have provided an opportunity to develop many of the design tools and establish some of the key parameters needed to proceed to a full scale demonstration. This study validated the expectation that nearly all of the major equipment and emissions control systems in an existing coal-fired plant could be directly utilized if the plant were converted to oxy-fuel firing. It has also reinforced the need for an inexpensive source of oxygen to make this option economical. Considerable opportunity exists for further refinement of this work toward the goals of optimized performance and cost. In portions of our oxy-fuel program, we have worked in collaboration with an international consortium state agencies supporting coal usage, USDOE, industrial gas companies providing oxygen, and utilities. Future Opportunities, Challenges, and Plans Preliminary assessment of the impact of oxy-fuel firing on the design of a new plant with a high efficiency state-of-the-art steam cycle has revealed potential opportunities for significant cost reduction. A higher efficiency advanced supercritical steam cycle reduces the amount of coal burned per megawatt generated which, in turn, reduces equipment sizes and oxygen required, as well as the amount of emissions, including carbon dioxide, produced. Current work has assumed the same amount of flue gas will pass through the boiler as in conventional units using air instead of oxygen. Reduction of the amount of flue gas recirculated to the boiler may be advantageous, further reducing new plant boiler size and associated cost significantly. An important secondary benefit of oxy-fuel firing of coal in a boiler is that, in addition to facilitating carbon management, it also significantly reduces nitrogen oxide (NOx) emissions. In a conventional plant using air, NOx is produced from two sources; a small amount of nitrogen in coal (fuel-NOX) and a larger amount of nitrogen in from the air used for combustion (thermal NOX). By using relatively pure oxygen and replacing the nitrogen with recirculated flue gas, much less NOX is produced since there is much less nitrogen is available. Furthermore, some of the NOX in the recycled flue gas will be reduced by reactions within the flame to molecular nitrogen. This may reduce the requirements for add-on NOx controls, such as selective catalytic reduction, to satisfy emission standards. We plan to continue development of the technology toward full-scale system design and demonstration. The following areas require further development work. Burner Development: A pulverized coal burner capable of introducing coal and oxygen into the boiler while minimizing the likelihood of an in-duct coal fire is critical to the successful implementation of the concept. The mixing of flue gas, coal, and oxygen, especially in the pulverizer and primary air lines, is an important safety-related design uncertainty. Other combustion systems such as cyclone firing may offer additional benefits not only to the fuel handling and combustion system but also by reducing boiler size. Burners can be developed for safe oxygen introduction that would reduce NOx, carbon monoxide, hydrocarbons and unburned combustibles in the fly ash. Full-scale Demonstration: A full-scale demonstration will be a critical event in establishment of commercial viability. It will provide the information and experience needed to allow plant suppliers to properly design and plant users to gain confidence in the technology's costs and ability to achieve the desired performance and reliability. In addition to the "normal" operating scenario, a full-scale demonstration would address such transient events as system start-up/shut-down and unplanned upsets. To minimize the full-scale demonstration costs and risks, the first application would likely involve conversion of an existing coal-fired plant to oxy-fuel firing, utilizing the existing equipment to the greatest extent possible. Since only a few new components would need to be purchased and installed, the most significant being the oxygen supply system, the project cost would be minimized. Risks also would be significantly reduced because most of the plant equipment would have already been operated; and, although some modification would be needed, the controls would be in place and proven. New Boiler Applications: One advantage of the oxy-fuel technology is that it can be retrofitted to the existing units allowing application to the coal-fired fleet. We anticipate that, based on the experience of the first (probably retrofit) application, opportunities will be identified for significant improvements toward optimization of subsequent retrofits and new plant applications. Oxygen Production: The cost of oxygen is a major economic hurdle for both oxy-fuel combustion and gasification technologies. Efforts are needed to minimize the cost of oxygen to improve economic viability for these oxygen-based technologies. Integration with Carbon Sequestration Process: As carbon sequestration approaches are identified, it will be necessary to evaluate the suitability of the oxygen-fired boiler flue gas. Even with good control over boiler air infiltration, and high efficiency SOX and NOX removal systems, the flue gas will still contain some N2, SO2, NO, NH3, etc. The impact of these contaminants will need to be evaluated before an integrated process can be defined. Schedule and Cost Costs for remaining research and development activities are anticipated to be about $1 million. The full-scale demonstration cost will be highly affected by site and program specific factors. As a premature and preliminary estimate, the demonstration might cost about $15 million. Figure 3 - Development Schedule
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