Materials at High Temperature Vol 20, Issue 1, 2003
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Preface
The papers in this Special Issue of Materials at High Temperatures were presented at a workshop entitled “Life Cycle Issues in Advanced Energy Systems” held in June 2002 at Woburn in the UK. It was the third in a series of international workshops addressing issues related to environmental degradation in advanced energy systems (the previous workshops were held in Petten, The Netherlands, 1993 and in Tampa, Florida, USA, 1997). A second Special Issue incorporating the rest of the papers presented at the workshop will be published later and bound Proceedings containing all of the papers submitted will also be published in mid-2003
Advanced energy systems are evolving rapidly, leading to a range of technologies that is increasingly diverse, yet which generate hot gas path environments that have many similarities. As a result, the scope of technologies embraced by these workshops has increased while maintaining the core theme of environmental degradation of materials. The following topics were covered during the Woburn Workshop:
� Operational experience related to advanced energy systems (8 papers);
� Mixed oxidant, gaseous corrosion (10 papers);
� Deposit-induced corrosion (6 papers);
� Synergistic influences (2 papers);
� Future perspectives (3 papers).
At the end of the formal presentations there was a concluding panel discussion which addressed important issues facing the power generation industry, as well as commentary upon the viability of different options facing the energy industry. Arapporteurs’ report which documents the main findings of the panel discussion will be published in the bound proceedings. Advanced energy systems considered included combustion and gasification technologies, using coal, biomass, waste and natural gas fuels. All classes of materials used in advanced energy systems were considered under the topics listed above. The future direction of advanced energy systems was given particular emphasis at the Workshop in order to provide a view of the implications for future research activities in environmental degradation. As with the two previous events, this workshop was successful in bringing together research scientists working on high-temperature corrosion and related fields with materials engineers and others involved in the design, construction and operation of advanced power plants. All contributions were invited lectures (there being no poster papers). Participants included leading active industrialists and researchers into corrosion and related issues in advanced energy systems from eight European countries, as well as Japan, Australia, New Zealand and the USA.
The workshop coordinators/editors would like to thank the authors, session chairpersons, discussion panel members, the rapporteurs and all delegates for their contributions in making the workshop a success. Sincere thanks are extended to Cranfield University staff: Sharon McGuire for her valuable organisational skills; Paul Kilgallon (Power Generation Technology Centre); and Prof. John Nicholls, European Editor of the Journal Materials at High Temperatures for their very active involvement and encouragement in all aspects of the workshop. The encouragement of Prof. John Stringer (EPRI) in holding this event is also gratefully acknowledged.
International Organising Committee of the 3rdWorkshop:
J.F.Norton: Consultant, PGTC, Cranfield University, UK.
N.J.Simms: PGTC, Cranfield University, UK
J.E.Oakey: PGTC, Cranfield University, UK.
R.J.Fordham: European Communities, NL.
S.Kihara: IHI, Japan.
T.Levi: MPT, New Zealand.
W.T.Bakker: EPRI, USA.
I.G.Wright: ORNL, USA.
Workshop Sponsors:
Cranfield University, Bedford, UK,
Institute for Energy, CEC Joint Research Centre, Petten Establishment, The Netherlands,
Electric Power Research Institute, Palo Alto, California, USA,
Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
The impact of increasing demand for efficiency and reliability on the performance of waste-toenergy plants
R.J. Fordham, D. Baxter, C. Hunter and T. Malkow
European Commission, Institute for Energy, JRC Petten, 1755 ZG Petten, The Netherlands
Waste-to-energy achieves two main objectives, the reduction in volume of waste and the recovery of energy. Volume reduction of waste is part of waste management while the use of waste as a fuel presents the opportunity to obtain electrical power and heat, thereby reducing the consumption of fossil fuels. The efficiency of waste-to-energy plants is therefore of considerable interest and substantial efforts are being made to maximize energy output from many plants. Plant efficiency can be considered in a number of ways and certain factors impose restrictions on the degrees of freedom when trying to achieve greater energy recovery. First and foremost, a waste incinerator is a tool within waste management and thus the waste (fuel) usually cannot be selected for composition and consistency. The provider of the operating license, the local authority, sends most of the waste to the incinerator. The operator usually has little scope to choose the waste stream, and consequently the energy input (calorific value of the waste) can vary and as a result will influence the steam parameters. However, regardless of the amount of energy recovered, very stringent limits on emissions to the environment must be respected as well as the pure waste management aspects. This paper addresses the main technical challenges facing wasteto- energy plant operators and the difficult balancing act that must be achieved between plant emissions, reliability and efficiency.
Keywords: waste-to-energy plants, plant efficiency
Operating experience and improvement opportunities for coal-based IGCC plants
Neville A.H. Holt
EPRI, 3412 Hillview Avenue, Palo Alto, CA 94304, USA
The four major coal-based IGCC plants, each of 250–300 MW, commissioned in the 1990s have now either entered or are about to enter full commercial service. These pioneer plants, two in the US (Tampa and Wabash), two in Europe (Buggenum and Puertollano) experienced the usual spate of problems during their initial two or three years of operation. However, these plants are now running at much improved availabilities similar to those of many other solid fueled plants. Furthermore the lessons learned from these pioneer plants suggest several areas where materials development could further improve the availability of IGCC plants as currently commercially offered. Even without the likelihood of carbon emissions related regulation, coal based IGCC technology is very close to being economically competitive with pulverized coal-fired (PC) plants and can meet extremely stringent environmental emission standards. IGCC is already commercially cost competitive in many worldwide locations when using petroleum residual feedstock. Moreover as a technology that has only recently moved to the commercial marketplace there is a very considerable upside potential for improvements in all the key components of IGCC technology over the next decades.
• Air separation units (ion transfer membranes (ITMs) or other new membranes)
• Gasification (feed systems, refractories, injectors)
• Gas cooling (higher temperature metals)
• Gas cleaning (S, N and trace elements – new sorbents)
• Separation of gas species (membranes CO2 and H2)
• Gas turbine advances (high-temperature materials, coatings)
• Advanced cycles (humid air turbine (HAT), O2/CO2, hybrids)
• Fuel cell cycles (lower cost materials, manifolds)
These future advances will depend on the development of new materials and designs, which if successful should provide better environmental and process performance, higher efficiency and reduced capital and life cycle costs.
Keywords: coal-based integrated gasification combined cycle plants
Experience with an ODS high-temperature heat exchanger in a pilot-scale HiPPS plant
John P. Hurley1, Daniel J. Seery2 and Fred L. Robson3
1University of North Dakota Energy & Environmental Research Center, PO Box 9018, Grand Forks, ND 58202-9018
2formerly United Technologies Research Center, 132 Indian Hill Trail, Glastonbury, CT 06033
3kraftWork Systems, PO Box 115, Amston, CT 06231
A very high-temperature heat exchanger (HTHX) composed of MA754 alloy is being tested in a coalfired slagging furnace system at the University of North Dakota Energy & Environmental Research Center. The HTHX was designed and built by the United Technologies Research Center. It is composed of three 6-foot-long by 2g-inch-od tubes which were originally protected from the products of combustion by ceramic panels. It was used to produce process air at 950°C and 150 psig over 2000 hours of testing with a variety of coals. For a short time, conditions of 1100°C and 100 psig were reached. In later tests the bare alloy tubes were exposed directly to the products of combustion which increased heat exchange coefficients by five times suggesting the HTHX cost would be only 1/10 as much as with the ceramic panels. Laboratory tests of the alloy exposed directly to the coal slag showed recessions of 5–10 mils per year at up to 1150°C. The data suggest that a cost competitive power system could be built employing this technology.
Keywords: high-temperature heat exchanger, HiPPS plant
ELCOGAS IGCC power plant in Spain: effect of the gasifier environment on the high alloy steel performance
A.M. Lanchaa, M. Alvarez de Laraa, D. Gómez-Briceñoa and P. Cocab
bCIEMAT. Avda. Complutense, 22. 28040-Madrid, Spain
bELCOGAS, S.A., C. T. GICC Puertollano. Carretera Calzada de Calatrava a Puertollano, km. 27. 13500-Puertollano, Ciudad Real, Spain
The ELCOGAS power plant in Puertollano (Ciudad Real, Spain), with a gross electrical output of 335 MWe, is the world´s largest capacity Integrated Gasification in Combined Cycle (IGCC) power plant. ELCOGAS is a Spanish joint stock company whose shareholders are European utilities and capital good suppliers from European countries. The gasification is based on the PRENFLO pressurized entrained-flow process with dry fuel dust feeding. The high-pressure (HP) evaporators, located in the same pressure vessel as the gasifier, are one of the most critical components in terms of materials in the gasifier. The corrosion performance of the austenitic Sanicro 28 alloy tubing exposed to the aggressive raw gas in the HP evaporators is being evaluated. For this purpose, destructive examination of calibrated test samples, installed at various accessible locations and removed after different exposure periods, is being performed. Corrosion results of Sanicro 28 samples with more than 11200 operating hours are available and show, in general, low corrosion metal losses in the high temperature gasifier atmosphere.
Keywords: Sanicro 28, coal gasification environment, high temperature corrosion
Life cycle issues of power plant in Australia and New Zealand
Tana P. Levi, Keith A. Lichti, Jonathan D. Morris and David M. Firth
Materials Performance Technologies, Industrial Research Limited, PO Box 31-310, Lower Hutt, New Zealand
Australia and New Zealand have markedly different energy mixes. In Australia over 90% of electricity is generated from non-renewable energy sources, predominantly coal. In contrast, New Zealand uses little fossil fuel and the main power generation is provided by hydro with a significant contribution from geothermal resources. This paper presents a brief history and description of the different types of fuel powered plant in use in these two countries, identifies some of the local life cycle issues and discusses research and development and management plans associated with these local renewable and fossil fuelled plant. Additionally brief case histories for the three major plant types are presented and future options in power generation are considered.
Keywords: life cycles, power generation, Australia, New Zealand
Corrosion behavior of ferritic steels on the air sides of boiler tubes in a steam/air dual environment
Kiyokazu Nakagawa1, Yasuo Matsunaga1 and Takahiro Yanagisawa2
1Research Laboratory , Ishikawajima-Harima Heavy Industries Co., Ltd, Tokyo, Japan;
2Boiler Basic Design Department, Ishikawajima-Harima Heavy Industries Co., Ltd, Tokyo, Japan
The corrosion behavior of heat resistant ferritic steels for boiler tubes in a steam/air dual environment simulating the non heated areas at 600°C has been investigated. Corrosion rates of the ferritic steels on the air sides under a condition of steam/air dual environments were increased more significantly than those in simple air conditions because of the permeation hydrogen from the steam side. Amounts of hydrogen permeated through the test tubes were measured electrochemically using a proton conductive solid electrolyte (5mol%Y2O3–SrCeO3) The results of hydrogen permeation current measurements show that the amount of permeated hydrogen from the steam sides decreased parabolically with time and decreased with increasing Cr content in the steels. The corrosion attack of the outer surfaces saturated under a certain permeated hydrogen level and the marginal hydrogen content needed to accelerate the corrosion of the air side depended on the Cr content in the steel. Therefore, a part of the permeated hydrogen react with oxygen to form H2O at the metal/oxide interface on the air sides. That is, the corrosion mechanism may be the same as that of steam oxidation.
Keywords: corrosion behavior, ferritic steels, boiler tubes
Materials degradation mechanisms in coal-fired boilers
Juan Carlos Nava and Jeff Henry
ALSTOM Materials Technology Center, Chattanooga, TN 37402, USA
The environmentally-induced degradation of materials operating at elevated temperatures in fossil-fired boilers may prove to be the most formidable obstacle standing in the path of the successful implementation of higher efficiency power generation systems. Corrosion and oxidation mechanisms are thermally activated processes, and the increased operating temperatures required to attain higher efficiencies in these power generation systems will limit the application of many materials that find extensive use in current equipment. Three of the major modes of materials degradation that are active in the existing fleet of coal-fired boilers in the US include: (1) accelerated sulfidation of waterwall tubing as a result of modified fuel combustion processes; (2) steam side oxidation; and (3) coal-ash corrosion. In this paper the current understanding of these corrosion phenomena will be reviewed and guidelines for future research approach will be outlined.
Keywords: material degradation, coal-fired boilers
Materials behavior in the Nuon Power IGCC Plant in Buggenum
Ir. Hans Pastoors
Nuon Power Buggenum BV, PO Box 4035, 6080 AA Haelen, Netherlands
Since 2001 the Willem–Alexander IGCC in Buggenum has been owned by Nuon, one of the largest energy and water companies in the Netherlands. After a short introduction into Nuon, an overview of recent plant performance figures and future plans with Green Power (biomass co gasification) is given. Over the past 48,500 operating hours completed at the plant several types of material failures have been encountered. In general terms it can be concluded that no cases of intrinsic material degradation have been seen. Failures have been attributed to imperfections in the ability to adhere in all details to the applicable design rules and conditions. Examples of damage as a result of erosion, corrosion and thermal cycling are discussed.
Keywords: materials degradation, erosion, corrosion, thermal cycling
Advanced clean coal technology in the USA
Lawrence A. Ruth
National Energy Technology Laboratory, U.S. Department of Energy, P.O. Box 10940, Pittsburgh, PA 15236-0940, USA
Coal is the most plentiful fossil fuel in the USA but its continued competitiveness with other energy resources will depend on the development of innovative technologies that enable the design of nearzero emission coal-based power plants. The US Department of Energy’s clean coal research, development, and demonstration programs address near-, mid-, and long-term technologies for improving the environmental performance, efficiency, reliability, and cost competitiveness of coal-based electricity generation. Vision 21, the long-term initiative to eliminate environmental concerns associated with coal use, focuses on technologies, including gasification, gas purification and separation, combustion turbines, fuel cells, and advanced steam cycles, that are likely to play key roles in the design of near-zero emission plants. These key technologies have in common the characteristic that they require advanced materials capable of withstanding aggressive environmental conditions and performing specialized functions when required. Examples of these critical materials include refractory linings for coal gasifiers, gas filters and sorbent systems to remove contaminants, ceramic membranes for separating oxygen from air and hydrogen from carbon dioxide, blading and other components for high-temperature combustion turbines, fuel cell electrodes and electrolytes, and boiler tubing and turbine components for advanced steam cycles. This paper describes technology pathways being pursued to achieve Vision 21 objectives and gives examples of advanced concepts, focusing on operating conditions and materials.
Keywords: advanced clean coal technology
Effects of cyclic operation on advanced energy conversion systems
F Starr
European Technology Development Ltd, Surrey, UK
The impact of plant cycling is evaluated for near and medium term advanced energy conversion systems in terms of effects on equipment and implications for the choice of materials. A brief outline is given of current problems and their causes in steam and combined cycle gas turbine (CCGT) plants. In contrast to earlier years, it is now quite common for relatively new plants to have to cycle. The causes of this are increased competition in the power supply industry, unforeseen changes in the relative price of fuels, and regulatory changes which no longer have the effect of insulating certain types of energy conversion systems from the need to load follow and two shift. It is therefore vital that the issue of cycling be considered at the plant design stage. In advanced steam plants, where steam inlet temperatures will be well over 600°C, problems will involve the performance of transition joints and austenitic alloys under cycling conditions. The“ R” function is described and tabulated to show the likely susceptibility of a range of ferritic, austenitic and nickel based alloys to thermal shock, caused by quenching of pipework by slugs of condensate. It would seem that even modern high strength austenitics do not have the same capability as the modified 9 and 12 Cr ferritics. There may also be problems with steam turbine materials. The main concern in advanced CCGT plants is the potential for increased thermal fatigue, due to the use of more sophisticated blade cooling techniques. However a potential issue is shortcomings in blade life assessment models as applied to directionally solidified and single crystal materials, as it seems likely that current approaches, using isotropic data, may be giving a severe over estimate. It seems unlikely that coal gasification plant will be able to two shift, although load following will be possible. It is suggested that the critical area will be that of the synthesis gas exchanger where there is potential for corrosion assisted fatigue. This problem is likely to increase if more resistant coatings are used, as these tend to be less ductile than current alloys. Conversely recuperative gas turbines are designed to load follow and two shift and should be able to resist the effects of rapid start ups and shut downs. Modern designs using either primary or secondary surface recuperators are briefly described. The topical issue here is passage collapse in primary surface systems, which is likely to increase under cycling duty.
Keywords: advanced energy conversion systems, cycling, steam plant, fireside corrosion, CCGTs, recuperators, IGCCs
Hot flue gas filtration experience at the Power Systems Development Facility
J. M. Wheeldon
EPRI, 3412 Hillview Avenue, Palo Alto, California 94304, USA
High-temperature, high-pressure (HTHP) filters are key components in the successful development of advanced coal-based power generation technologies, including integrated gasification combined cycles and pressurized fluidized-bed combustion (PFBC). In these applications the HTHP filters protect the downstream gas turbine from particle-related damage and clean the process gas to satisfy dust emission standards. HTHP filter systems have been under development worldwide for over 20 years. One of the objectives has been to identify filter elements capable of operating at temperatures above 850°C with commercially acceptable lifetimes. Because of the high temperatures and corrosive environments involved, ceramic filter materials have been the most widely tested. Such elements have proven prone to failure through several mechanisms, thereby lowering the overall reliability of the filter system and so impeding commercialization of the associated advanced power generation technology. The US Department of Energy (DOE) established the Power Systems Development Facility (PSDF) in 1994 to further development of components for these advanced technologies, especially HTHP filtration. This paper presents some of the test data collected during HTHP filtration of flue gas that relates to materials issues. The results are discussed and used to identify the course of future test work
Keywords: high-temperature, high-pressure filters
Operational experience of USC steam condition plant and PFBC combined cycle system with material performance
Kensuke Yamamoto, Ichiro Kajigaya and Hideo Umaki
Ishikawajima-Harima Heavy Industries Co.,Ltd, 3-2-16 Toyosu Koto-Ku, Tokyo, Japan
In Japan, many conventional coal-fired power plants have been introduced, because coal fuel has many advantages in terms of price and availability, compared with oil and gas. In December 1997, the Kyoto Protocol that was adopted at the COP3 meeting (the Third Conference of the Parties to the United Nations Framework Convention on Climate Change) committed Japan to reduce its greenhouse gas emissions to 6% below 1990 levels during the commitment period to 2012. To help meet such environmental requirements, coal-fired plants need to improve their thermal efficiency. Promising candidates of high efficiency coal-fired power plant are Ultra Super Critical (USC) steam condition pulverised coal plant and Pressurised Fluidised Bed Combustion (PFBC) combined cycle. Recently most of Japanese thermal power plants have adopted USC steam conditions, because in Japan there are a lot of fully developed materials whose costs are compatible with the excellent performance of these plants. In April 2002 EPDC (Electric Power Development Co., Ltd) 600MW Isogo New Unit 1 began commercial operation, with the highest steam condition in Japan. It replaced two former coal-fired 265MW plants. This boiler was designed and manufactured by Ishikawajima-Harima Heavy Industries Co., Ltd (IHI). In this unit, 12Cr ferritic heat resistance materials (ASME P122 & T122) were applied to the main pressure parts in high-temperature regions, because of their excellent properties such as high creep rupture strength and high oxidation resistance up to 650°C. These properties play an important role to reduce tube and pipe wall thickness and hence costs. PFBC combined cycle system is a new coal utilization system capable of higher thermal efficiency with compact unit size and excellent environmental adaptability. IHI had intensive research and development efforts for commercialization of PFBC with 3MW test facility in IHI’s workshop and a license agreement concluded with ABB Carbon AB in Sweden (Alstom Power Sweden at present) for the PFBC technology in 1990. Then IHI designed and fabricated EPDC Wakamatsu 71MW pilot plant and Kyushu Electric Power Co., Inc. (KyEPCO) developed the Karita 360MW commercial plant. Karita, using a former pulverized coal-fired unit infrastructure, is the largest PFBC combined cycle system in the world. In this unit, many new materials have been applied in the boiler systems. SPV490, developed by IHI and Japanese steel manufacturers, was used for the pressure vessel and contributes to a weight and cost reduction of approximately 10%. A new austenitic steel, NAR-AH4 having excellent erosion/ corrosion resistance and high creep rupture strength, developed by IHI and SMI (Sumitomo Metal Industries Co., Ltd) was used for high-temperature components (cyclone and hot gas ducts, etc). This steel is expected to be used widely as a candidate material for high-temperature components. This paper presents operational experience from high efficiency coal-fired thermal power plants focussing on material performance, which play a key role of these plants.
Keywords: Ultra-SuperCritical Steam Plant, Pressurised Fluidised Bed Combustion and Boiler Systems