br-1884

Advanced Ultra-SupercriticalPower Plant (700 to 760C) Design for Indian Coal Technical Paper BR-1884 Authors: P.S. Weitzel, PE J.M. Tanzosh B. Boring Babcock & Wilcox Power Generaton Group, Inc. Barberton, Ohio, U.S.A. N. Okita T. Takahashi N. Ishikawa Toshiba Corporaton Tokyo, Japan Presented to: Power-Gen Asia Date: October 3-5, 2012 Locaton: Bangkok, Thailand Babcock & Wilcox Power Generation Group 1 Advanced Ultra-Supercritical Power Plant (700 to 760C) Design for Indian Coal P.S. Weitzel J.M. Tanzosh B. Boring Babcock & Wilcox Power Generation Group, Inc. Barberton, Ohio, USA Presented at: Power-Gen Asia Bangkok, Thailand October 3-5, 2012 BR-1884 Abstract The advanced ultra-supercritical (A-USC) power plant operating with steam temperatures at 700 to 760C (1292 to 1400F) will require nickel-based alloy materials in the steam generator, critical steam piping and steam turbine. Nickel- based alloy development from the United States (U.S.) Advanced Materials Research Program will be presented, as well as issues related to component materials selection for an Indian coal. Babcock & Wilcox Power Generation Group, Inc. (B&W PGG) is developing an A-USC plant for 700C steam conditions in collaboration with turbine designer and manufacturer, Toshiba Corporation (Toshiba). The plant layout to accommodate the new equipment at the lowest cost will need to consider new confguration arrangements. The operability and maintainability is a major consideration affecting arrangement. The steam generator design arrange- ment, plant layout and control methods will be described. Operation at 700C provides an effciency improvement to reduce carbon dioxide (CO 2) emissions and reduces coal in- frastructure demands, some of the primary goals for A-USC steam conditions. A cost comparison between conventional power plant design and conditions, and those of an A-USC plant, is included. Introduction A power industry goal is to reduce CO2 emissions from coal-fred electric generating plants with improved thermal effciency by increasing steam temperatures to +700C. Costs for carbon capture would be lower due to less CO2. There will be an increase in generating capital due to the required use of nickel alloys. The means to limit the cost increase is the reduction in equipment size per MW, less resources consumed, less impact to infrastructure demands, and the lower cost of emission control. Improving the utilization of abundant and affordable coal is being undertaken worldwide by organizations through materials development programs. A plant operating at 700C/730C plant compares favorably with the current state-of-the-art steam generating plant operating at 600C/610C by requiring approximately 11% less coal and producing 11% less CO2 to generate the same power output. Considerable progress has been made in the develop- ment of new alloy materials needed for an advanced ultra- supercritical +700C plant. Boiler materials development programs to address needs and qualifcation by design codes have been underway for more than 10 years in Europe (Thermie AD700) and the United States [U.S. Department of Energy/Ohio Coal Development Offce (DOE/OCDO)]. The METI Cool Earth program in Japan started in 2008 [1]. Laboratory, pilot-scale and in situ boiler component tests have been performed on various materials. Programs in Europe, the U.S., and Japan are intended to further develop materials understanding and carefully put the technology into practice [2, 3, 4]. Some of the newly developed nickel alloy products (740H, 282) offer better performance and will need to un- dergo tests on larger diameter pipes in service conditions. Planning for these component tests, along with other needed parts and accessories, has begun. Another previous program N. Okita T. Takahashi N. Ishikawa Toshiba Corporation Tokyo, Japan 2 Babcock & Wilcox Power Generation Group to note is the High Performance Steam System (HPSS) sponsored by the U.S. Department of Energy (U.S. DOE) in the mid-1990s and conducted by Solar Turbines to develop a 1500F/1500 psig steam turbine for cogeneration. A 4 MW steam turbine, throttle control valve, and once-through steam generator was constructed and operated at full temperature conditions [5]. By making an assessment of the previous A-USC component testing already conducted, and then completing the further testing of newer component materi- als, the industry and future owner-operators will be able to reduce the risks for proceeding to the prototype plant phase. The next step to take is the planning, design, fabrication, construction and operation of the lead prototype +700C dem- onstration plants. Demonstrating the commercial viability and success in meeting the value required in the market place is the next milestone. Proving the capability of the supply chain, actually performing the plant installation, and placing the equipment in the control of the personnel that operate and perform maintenance will demonstrate whether or not the risks are acceptable to the industry. The designs for A-USC boilers started with the currently acceptable confgurations which are two-pass or tower style arrangements [6, 7]. The earliest proposed designs have been employed for about the last half century. An important need is the recognition to carefully consider the arrangement of the steam generator and the location in the plant arrangement relative to the steam turbine because of the need to use high cost nickel alloy steam leads. The steam generator steam outlets would be moved closer to the steam turbine inlets by physical repositioning or by using non-conventional ar- rangements. There have been designs proposed to arrange the boiler to have horizontal gas fow or to put part of the steam turbine up near the top of the steam generator close to the superheater outlet to shorten the high energy steam piping. Traditionally, the power industry is very conserva- tive and reluctant to accept radical changes to designs and procedures before adequate testing and demonstrations are conducted to prove the economics and technical benefts. However, there appears to be some recognition in the power generation community of the need for a new arrangement paradigm. There are earlier steam generator design arrange- ments that employ some of these proposed features. Steam generator materials development The advancement to 700C steam temperatures for coal fring represents an increase of 166C (300F) above the av- erage predominant operating experience. The current state- of-the-art plant uses 600C (1112F) technology, which is not widely applied so that vast industry experience is lacking or limited in the knowledge base. The introduction of the 700C technology has to overcome the reluctance to adopt A-USC plants by conducting development programs that test and demonstrate that the risk is acceptable for a very capital intensive industry. Pioneering technology introductions such as American Electric Power Philo 6 (31MPa, 621C, 565C, 538C) in 1957, and Philadelphia Electric Eddystone 1 (34.5 MPa, 649C, 565C, 565C ) in 1959 can provide valuable lessons in meeting challenges [8, 9]. The low height of the Philo 6 steam generator should be noted as it provides an example of a confguration that is extremely different than currently accepted boiler confgurations, and has the feature of reducing the length of steam lead run to the steam turbine. See Figure 1. B&W PGG is a member in the consortium for the U.S. DOE/OCDO Materials Development Program for A-USC along with other suppliers and research organizations. The major aspects of this program are to perform work tasks in: conceptual design and economic analysis, mechanical prop- erties, steam side oxidation, freside corrosion, weldability, ease of fabrication, coatings, and design data and rules. As an example, the program developed a new formula for calculating material thickness, Appendix A-317, adopted by Section I of the American Society of Mechanical Engineers (ASME) code, and the code case acceptance of alloy INCO 740 nickel for pipe and tube in the ASME I Code. This and other new materials allow for improved design performance of a +700C steam generator [6]. There is also a DOE/OCDO program associated with the development of steam turbine materials with participation of major turbine suppliers. Welding development The DOE/OCDO Boiler Materials Program, has de- veloped the necessary welding procedure and weldment property data for several new alloys. Dissimilar alloy welds for many tubing combinations were performed and tested. For thicker sections representing pipe and headers, large plates and pipes have been welded and procedures qualifed in thicknesses never previously needed for boiler service. Nickel alloy plates of 617, 230 and the new INCO 740 ma- terial for boilers were the selected candidates. Nickel alloy 282 has been more recently included in the program and work is in progress to gain experience and develop welding procedures for ASME Code acceptance. Fig. 1 AEP Philo 6 universal pressure steam generator, B&W Contract UP-1. Babcock & Wilcox Power Generation Group 3 Materials selection The materials shown in Table 1 are available for applica- tion in steam generators designed to ASME Section I, except for Haynes 282 which is being prepared for submittal of a code case. Alloy 740H was approved in Code Case 2702. For current design studies, the materials chosen are carbon steel, T12, T22, T92, 347HFG and 740H. Nickel alloys 617 and 230 are also candidates, but have lower allowable stress properties than 740H. For economic reasons, 740H presently has the advantage for tube and pipe selection where lower weight will be required. This material has the highest strength, as well as very good steam side and freside cor- rosion resistance, at a price per weight comparable to the other candidate alloys. The allowable stress values for materials listed in Table 1 are graphically depicted in Figure 2. Steam generator confguration New boiler arrangements have been proposed that pri- marily change the steam lead terminal point on the steam generator. There has been some consideration for placing the boiler partially in the ground and/or raising the steam turbine pedestal. Some have considered dividing the turbine; for ex- ample, the high pressure (HP) and intermediate pressure (IP) sections could be located at the higher elevation and the low pressure (LP) section could be located at the conventional pedestal condenser location. One designer has proposed a boiler design that lays the boiler down with a horizontal gas fow and the steam turbine immediately at the side. For U.S. coals the B&W PGG design arrangement for the conventional 600C boiler is a two-pass type (Carolina) with parallel gas path biasing for reheat steam temperature control, shown in Figure 3. The two-pass boiler is considered to have the following advantages: 1. shorter steel structure than a tower design, 2. time savings of parallel construction sequence, 3. less complicated high temperature tube sections support, 4. more economical to erect, and 5. less sootblowing required to clean the pendant surfaces than high temperature horizontal surfaces in the tower design. The tower design is considered to have the following advantages: 1. better gas fow distribution resulting in lower tube metal upset temperatures, 2. wider tube spacing allowing high fuel ash removal to a single furnace hopper, 3. more drainable heating surface, 4. steam lead outlets positioned closer to the steam turbine, 5. increased ability to handle internal oxidation exfolia- tion with distribution along the tubes, and 6. ability to successfully fre high fouling brown lignite. The modifed tower combines features of both designs: the structure is shorter than the standard tower design, and steam leads are shorter and nearer to the steam turbine. B&W PGG is also developing a modifed tower for A- USC (a “folded” tower similar to the two-pass style with horizontal tube banks) and parallel gas path biasing in the downpass. This arrangement is not new to the industry. For an A-USC boiler using Indian coal, the modifed tower with gas recirculation (GR) is used in a series back pass arrange- ment because the gas velocity limits are very low due to the very high ash content in the Indian coal and the heating surface area becomes larger and less effective without GR. (See Figure 4.) To achieve a wider range of reheat (RH) temperature control turndown, gas bias with a parallel pass and GR might also be included. RH control priority in this design would be to position the biasing dampers and then complement with gas recirculation fow. Table 1 Materials Selection for Steam Generator Components Alloy Composition (Nominal) Application 210C, 106C Carbon steel Econ, piping, headers T12 1Cr-0.5Mo Water walls T22 2.25Cr-1Mo Water walls, RH T23 2.25Cr-1.6W-V- Nb Water walls, RH T91 9Cr-1Mo-V Water walls, RH T92 9Cr-2W Water walls, RH, piping 347 HFG 18Cr-10Ni-Nb SH, RH 310 HCbN 25Cr-20Ni-Nb-N SH, RH Super 304H 18Cr-9Ni-3Cu- Nb-N SH, RH, piping, headers 617 55Ni-22Cr-9Mo- 12Co-Al-Ti SH, RH, piping, headers 230 57Ni-22Cr-14W- 2Mo-La SH, RH, piping, headers 740H 50Ni-25Cr-20Co- 2Ti-2Nb-V-Al SH, RH, piping, headers 282 58Ni-10Cr-8.5Mo- 2.1Ti-1.5Al Piping, headers Fig. 2 Expected material ASME I Code allowable stress. 4 Babcock & Wilcox Power Generation Group Design of a steam generator using indian coal Indian coals that are widely used for new power projects in India are generally low sulfur content and have a reduced likelihood of freside corrosion problems. U.S. western coals from the Powder River Basin (PRB) are similarly low in sulfur and have fared much better regarding coal ash corro- sion testing. Low sulfur U.S. coals are preferred in the fuels selection for A-USC applications by providing lower risk to freside corrosion. Low sulfur Indian coals are expected to have this same lower risk for freside corrosion. However, the ash content of Indian coals is very high and the silica/quartz content is very high, thus very erosive, requiring much lower gas velocities passing through the convection tube banks, about 50% less than a higher grade U.S. coal. Special erosion protection provisions are also re- quired on the pulverizers and boiler components. The impact to the design arrangement and cost is signifcant. The size of the gas fow area increases about 50% and the amount of heating surface increases due to lower heat transfer rates. Compared to a boiler using U.S. eastern bituminous coal, the furnace of a boiler using Indian coal is about 78% larger in volume and about 50% taller. Lower furnace exit gas temperatures are specifed. The furnace width is about 38% more, impacting the length of the nickel alloy superheater/ reheater outlet headers. Furnace wall average absorption rates are lower while the peak rates will be expected to be nearly the same. Staged fring for nitrogen oxides (NOx) reduction may be required at some plants. The lower furnace walls may be fabricated starting with lower chrome steel, T12, and T22 for the middle water walls. The A-USC upper water walls of the furnace will operate at about 55C (100F) higher temperature than current practice and thereby require different material. At this higher temperature T92 tubing is preferred for wall construction and brings new welding procedures to the furnace erection requirements. B&W PGG has been performing R&D on T92 panel fabrication, erection and repair procedures [6]. Convection heating surface is arranged sequentially as follows: 1) from the furnace exit plane with the primary superheater platen, 2) three superheater banks in parallel gas fow, 3) reheat outlet banks in parallel/counter fow, 4) over the pendant crossover with the pendant reheat inlet bank, 5) primary superheater banks interlaced with the horizontal reheat banks, and 6) economizer banks. A vertical or spiral tube furnace enclosure may be used based on the steam fow to perimeter ratio. With Indian coal and its larger furnace perimeter requirement, a spiral design is used. The heating surface arrangement and steam temperature control method will need to result in component operating temperatures that change very little versus load, refer to reference [6]. It is desirable not to have large magni- tude changes in the material temperature of thick components like the superheater and reheater outlet headers. Rapid cyclic temperature changes will cause fatigue damage and reduce component life. The vertical steam separator (VS) is a thick wall component that must be located in the steam generator fow sequence considering the cyclic temperature changes of start up and load changing. The location will also impact the Benson point load where the steam generator will begin to operate in once-through mode. Fig. 3 Conceptual design of a two-pass (Carolina) A-USC boiler using U.S. coal. Fig. 4 Conceptual design of an 840 MW modifed tower A-USC. Babcock & Wilcox Power Generation Group 5 A-USC steam generator control and operation The B&W PGG A-USC plant design operates at full load above critical pressure 22.1 MPa (3208 psia) and on a vari- able pressure ramp at lower load so it is capable of permitting appropriately located dryout to occur when the furnace is in the subcritical pressure two-phase region. Control must handle the transition from the minimum circulation fow recirculating mode for initial fring using the boiler circulation pump to the once-through mode where all the water entering the economizer leaves from the superheat- er outlet. Control of the equipment must achieve cold startup, warm restarts, hot restarts, load cycling and shutdown. The load where the vertical steam separator runs dry is called the Benson point. For A-USC, this is estimated to be at about 45% load. At this dry separator point, the boiler circulation pump is shut off and the boiler feed pump is controlled so the feedwater fow will meet the demanded furnace enthalpy pickup function (from the economizer outlet to the primary superheater inlet) in once-through operation. Final steam temperature control range meets set point from about 50 to 100% load. Reheat steam temperature control range meets set point from about 60 to 100% load. Steam temperature is controlled by multiple stages of spray attemperation. The steam temperature control for faster transients must account for the time delay of the wa- ter entering the economizer to leave the superheater outlet, which takes about 15 minutes at minimum circulation fow load, and about 3 minutes at maximum continuous rating (MCR) load. A-USC turbine conditions The OCDO/DOE study conditions at the boiler terminals are: 792 MW gross; 34.6 MPa (5015 psia) throttle and 36.2 MPa (5250 psia) superheater; 735.6C (1356F) / 761C (1402); 333C (631F) feedwater; 508.4 kg/s (4,035,000 lb/hr) main steam; and 389.2 kg/s (3,089,000 lb/hr) reheat. HP cooling steam is 7.6 kg/s (60,318 lb/hr) at 566C (1050F) from the primary superheater outlet. Since this study began (in 2002), the throttle pressure has not been changed, although a lower pressure is now considered very likely. Studies in the 1980s and early 1990s used 44.8 MPa (6500 psi) [10]. The avail- able energy with a given steam temperature reaches a fat gradual optimum as a function of pressure so that the expense of high design pressure will increase cost more rapidly than the beneft to thermal effciency. In the current B&W PGG and Toshiba design study using an Indian coal specifcation, the steam conditions are: 30 MPa (4350 psia), 700C (1292F throttle / 730C (1346F) reheat, 330C (626F) feedwater, to produce 840 MW gross generation. Turbine rotor welding development The rotor is one of the largest components of the steam turbine system. (See Figure 5.) The weight of a high pres- sure turbine rotor or intermediate pressure turbine rotor is over 20 tons. The materials and design for rotors are unique to each manufacturer. Rotors for Toshiba’s A-USC design involve welding nickel-based alloy and ferrite steel to minimize use of expensive nickel-based alloy, and due to diffculties in producing a large ingot for mono-block nickel-based alloy rotors. As shown in Figure 5, the middle of the rotor is nickel-based alloy, and the ends are ferrite steel. Actual size weld trials are being conducted that test welding nickel- based alloy TOS1X-II to ferrite steel, and welding TOS1X-II to TOS1X-II. The welds will be evaluated for mechanical properties later this year. Turbine materials Table 2 shows candidate materials for application in high temperature turbine components designed by Toshiba. For current A-USC turbine design studies, it is necessary to apply nickel-based alloys for rotor forging materials. Nickel-based alloys for rotors are required for high creep strength at elevated temperatures. (See Table 3.) The ability to forge and weld are also important issues for large rotor production. The castings of a steam turbine are large struc- tures with complex shapes that must provide the pressure containment for the steam turbine. The major requirement for casing materials is the ability to cast them into the required size and shape through the air casting process. Weldability is also an important issue for pipe connecting Fig. 5 Steam turbine welded rotor. Table 2 Candidate Materials for High Temperature Turbine Components Components Properties Candidate Materials Rotor High creep strength Good forge-ability in the large size Good weld-ability TOS1X TOS1X-II Casing High creep strength Good cast-ability in the large size Good weld-ability Alloy625 TOS3X etc. Valve chest High creep strength Good cast-ability in the large size Good weld-ability Alloy625 TOS3X etc. Blade and bolt High creep strength Machine-ability Alloys used in gas turbines (U520, IN738LC, etc.) 6 Babcock & Wilcox Power Generation Group and repair welding. Blades and bolts will also be made of nickel-based alloys. Figure 6 shows the creep rupture strength of conventional steels and nickel-based alloy for turbine rotor candidates. TOS1X and TOS1X-II have higher creep strength than al- loy 617. These materials have demonstrated good forging and welding characteristics. For turbine casing and valve chest, TOS3X provides potentially better creep strength than alloy 625. Steam turbine confguration Figure 7 shows a conceptual drawing of Toshiba’s single reheat steam turbine system of a 840 MW power plant with 30 MPa (4350 psi), 700C (1292F) for main steam, and 6 MPa (870 psi), 730C (1346F) for reheat steam. It consists of a single fow HP turbine, a double fow IP turbine, and a double fow LP turbine with 48 in. last stage blade length. For the HP and IP turbines, nickel-based alloys are ap- plied to those parts directly in contact with high temperature steam. These include the inner casing, high temperature rotor, nozzle box (frst stage nozzle), and higher tempera- ture nozzles and blades. The other parts are constructed of conventional ferrite steel. Rotor designs require dissimilar welding nickel-based alloys (TOS1X-II) and ferrite steels to minimize the weight of expensive nickel-based alloys, and due to diffculties in producing a large mono-block nickel- based alloy ingot. Conventional cast steel can be used for the outer casing because high temperature steam is isolated by cooling steam. Materials and confguration for the LP turbine are similar to that for the 600C class USC turbine. Performance A comparison of the technical operating parameters be- tween 600C USC and 700C A-USC is summarized in Table 4. Thermal effciency is improved by 6% with 700C A-USC steam conditions. Steam turbine generator consists of one single fow HP turbine, one double fow IP turbine, one double fow LP tur- bine, and one generator in a tandem arrangement. (See Figure 8.) The overall length of the turbine-generator is 42 m. The LP turbine is downward exhaust. The turbine is rated at 840 MW gross with steam inlet conditions of 30 MPa and 700C, reheat to 730C. The rated speed is 3000 rpm. Main steam from the boiler fows through the four main stop valves and four control valves and enters the HP turbine. It expands through the HP turbine and exhausts as cold reheat to the boiler. Hot reheat steam from the boiler fows through the four reheat stop valves and four intercept valves and enter the IP turbine. It expands through the IP turbine and then enters the crossover piping, which transports the steam to the LP turbine. The steam expands through the LP turbine and exhausts into the condenser. The steam turbine is oper- Fig. 6 10 5 hour creep rupture strength of turbine rotor alloys. Table 3 Chemical Composition of Nickel-Based Alloys for Turbine Rotors Ni C Cr Al Ti Mo Co Ta Nb Alloy 617 Bal. 0.05 ~ 0.15 20.0 ~ 24.0 0.8 ~ 1.5 <0.6 8.0 ~ 10.0 10.0 ~ 15.0 -- -- TOS1X Bal. 0.05 23 1.6 0.3 9 12.5 0.1 0.3 TOS1X-II Bal. 0.07 18 1.25 1.35 9 12.5 0.1 0.3 Fig. 7 Conceptual drawing of an A-USC turbine (840 MW, 30 MPa, 700/730C). Fig. 8 Plan view of A-USC turbine (840 MW, 30 MPa, 700/730C). Babcock & Wilcox Power Generation Group 7 ated in throttle governing, sliding pressure. Sliding pressure improves the effciency of partial load operation. The turbine provides for nine feedwater extraction points. Final feedwater temperature at full load is 330C with de- superheaters. The steam turbine exhaust pressure at design conditions was selected based on typical Indian conditions at the condenser. The electrical generator is rated at 1050 MVA, 50Hz with a power factor of 0.85. Table 5 lists the turbine and major auxiliary equipment design parameters. A-USC steam generator and steam turbine – cost allowance with U.S. coal In 2003 as part of the DOE/OCDO Boiler Materials De- velopment project, the current U.S. two-pass steam generator design arrangement was evaluated on the basis of economic viability.[2, 3] It was determined that with the improved heat rate for the 750 MW net A-USC plant, the breakeven cost of electricity was attainable when the capital cost was within 13% above the cost of a conventional subcritical plant. The higher plant effciency allowed cost reductions because of the lower fuel cost per MW and smaller size of the equipment for the steam generator and the boiler balance of plant (fuel handling, emissions systems, fans and auxiliary power, etc.). The steam generator cost would need to stay within 40% above the cost of the steam generator of a subcritical plant. The DOE/OCDO A-USC steam generator had 7% more suspended weight than the conventional supercritical unit while it was 20% narrower. The narrower arrangement reduces the cost of the alloy headers and piping. There is a 13% weight increase of the overall tubing due to the lower temperature difference of the fue gas to steam resulting in lower heat transfer rates. The resulting cost estimate for the A-USC steam generator was 28% above the subcritical boiler and within the 40% allowance. Nickel alloy tubing is estimated to cost 46 times the cost of a T22 tubing. A current estimate is being developed to adjust to a newer assessment of nickel alloy cost for the steam leads between the boiler and steam turbine. The al- lowance for capital cost of the steam generator and steam turbine is expected to require less than a 25% increase over a subcritical plant. Conclusion A primary need in A-USC development is to confrm the capability of suppliers to support the new materials required and to meet the schedule demands so plant projects may be initiated. Suppliers will need to make investments based on increased certainty of the timing when the A-USC market demand will form. First generation demonstration plants are needed to establish a working understanding of the necessary relationships and put into practice the procurement standards for A-USC components. The value of owning an A-USC power plant will be determined by the balance of lifecycle cost saving of the impact to resource demands and infrastructure requirements with the increased capital cost of using nickel-based alloys. Table 4 Operating Parameters for 600C USC and 700C A-USC Turbine Arrangement 600C USC 700C A-USC General output 840 MW 840 MW Main steam (pressure and temp.) 24.1 MPa, 600C 30 MPa, 700C Reheat steam (pressure and temp.) 4.3 MPa, 600C 6.0 MPa, 730C Condenser pressure 683 mm Hg vac. 683 mm Hg vac. Boiler feedwater temp. 292C 330C Thermal efficiency Base 6% improvement Table 5 Turbine and Major Auxiliary Equipment Steam turbine Tandem-compound (three casings) High pressure section Single flow Intermediate pressure section Double flow Low pressure section Double flow Rated speed 3000 rpm MSV/CV 4 valves CRV 4 valves Overload valve 1 valve Feedwater pumps Electrically driven Heater De-superheater 1 or 2 HP heater 4 heaters Deaerator 1 deaerator LP heater 4 heaters Generator Number of poles 2 Power factor 0.85 Rated output 1005000 kVA Cooling Water 8 Babcock & Wilcox Power Generation Group References 1. Topper, J., “Status of Coal Fired Power Plants World- Wide”, IEA, www.iea-coal.org. 2. Bennett, A.J., Weitzel P.S., Boiler Materials for Ultra- supercritical Coal Power Plants – Task 1B, Concep- tual Design, Babcock & Wilcox Approach, USC T-3, Topical Report, DOE DE-FG26-01NT41175 & OCDO D-0020, February 2003. 3. Booras, G., “Task 1 C, Economic Analysis”, Boiler Materials for Ultra-supercritical Coal Power Plants, DOE Grant DE-FG26-01NT41175, OCDO Grant D-00-20, Topical Report USC T-1, February 2003. 4. Viswanathan, R., Shingledecker, J., Phillips, J., In Pursuit of Effciency in Coal Power Plants, (ed. Sakres- tad, BA) 35th International Technical Conference on Clean Coal and Fuel Systems 2010, Clearwater, FL, June 2010. 5. Duffy, T., et.al., “Advanced High Performance Steam Systems for Industrial Cogeneration,” Final Report on DOE Contract No. AC02-85CE40746, DOE/ CE/40746-TI (1987) 6. Weitzel, P.S., “Steam Generator for Advanced Ultra- Supercritical Power Plants 700 to 760C”, ASME Power 2011, Denver, CO (2011). 7. Rao, K.R., (ed.), Energy and Power Generation Hand- book, ASME, New York, 2011. 8. Kitto, JB, Stultz, SC., Steam/its generation and use, Edition 41, The Babcock & Wilcox Company, Bar- berton, OH 2005. 9. Silvestri, G.J., “Eddystone Station, 325 MW Gener- ating Unit 1-A Brief History,” ASME, March 2003. 10. Silvestri, G.J., et.al., “Optimization of Advanced Steam Condition Power Plants,” Diaz-Tous, I.A., (ed.), Steam Turbines in Power Generation – PWR-Vol. 3, Book No. H00442, ASME, 1992. Benson is a registered trademark of Siemens AG. Copyright© 2011 by Babcock & Wilcox Power Generaton Group, Inc. a Babcock & Wilcox company All rights reserved. No part of this work may be published, translated or reproduced in any form or by any means, or incorporated into any informaton retrieval system, without the writen permission of the copyright holder. Permission re- quests should be addressed to: Marketng Communicatons, Babcock & Wilcox Power Generaton Group, Inc., P.O. Box 351, Barberton, Ohio, U.S.A. 44203-0351. Or, contact us from our website at www.babcock.com. 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