| 1. |
- Boman, Christoffer, et al.
(författare)
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Development of innovative small(micro)-scale biomass-based CHP technologies
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- To enhance the overall efficiency of the use of biomass in the energy sector in Europe, the large electricity production potential from small-scale biomass heating systems should be utilised. So far, no technologically sound (in terms of efficiency and reliability) and economically affordable micro- and small-scale biomass CHP technologies are, however, available. Therefore, the present ERA-NET project (MiniBioCHP) aimed at the further development and test of new CHP technologies based on small-scale biomass combustion in the electric capacity range between some W and 100 kW. Within the project, an international consortium consisting of 12 partners from 4 countries, including university institutions, institutes and industry (both engineering and manufacturing), collaborated closely to perform high level R&D on three promising micro/small-scale biomass based CHP technologies which are covering a broad range of applications in the residential heating sector. The Austrian engineering company BIOS, coordinated the international project. The project was based on earlier basic research and development work related to these promising new technologies and aimed at the achievement of a technological level which allows a first (commercial) demonstration after the end of the project. The three CHP concepts included in the MiniBioCHP project were;1. Pellet stoves with a thermoelectric generator (TEG)2. Small-scale biomass boilers (10-30 kWth) with a micro-ORC process3. High temperature heat exchanger (HT-HE) for an externally fired gas turbine (EFGT)The Swedish part of the project was focused on the development of the concept of biomass based EFGT with dedicated R&D activities related to the development of the HT-HE system. The Swedish project consisted of the research partners Umeå University (project leader), Luleå University of Technology, Chalmers University of Technology and RISE Research Institutes of Sweden, together with the industrial partners Enertech AB/Osby Parca and Ecergy. The expertise of the Swedish partners regarding ash related problems, grate boiler combustion and modelling, deposit formation and high temperature corrosion, were combined with the know-how of a Polish partner regarding HT-HE design, construction, testing and optimisation.The HT-HE is the most crucial component in EFGT processes significantly influencing the investment costs, availabilities as well as the efficiencies that can be achieved. With a thermal capacity from several hundred kW up to 2-3 MWth) the CHP technology based on a biomass boiler and an EFGT is suitable for district heating systems, or process heat consumers. The electricity produced by the gas turbine (up to some 100 kWel) can be used to cover the own electricity consumption of a company and/or fed into the grid. Even though the concept of biomass based EFGT has been an interesting alternative for small-scale CHP production for some decades, and R&D activities have been undertaken, tackling both economic and technical aspects, only a few pilot-plants have been in operation and no initiative has so far reached the level of commercial implementation. Thus, the concept of EFGT fed with biomass is still considered to be in a rather early development stage and the main technical challenges are related to alkali deposit induced corrosion and thermal stress of the HT-HE material, turbine design/operation and system integration.Within the present project, a HT-HE prototype aimed for an EFGT system was therefore designed, constructed and successfully tested at flue gas temperatures up to 900°C. Thus, appropriate guidelines for a compact design of the HT-HE and recommendations have been worked out to minimize thermal stresses as well as ash related problems regarding ash deposit formation and high temperature corrosion in a biomass boiler system. Furthermore, different concepts for the overall biomass based EFGT system have been worked out and evaluated. The outcome of the project will hopefully be used in the further development work and form the basis for a first testing and demonstration plant within the coming years.
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| 2. |
- Fahnestock, Jesse, 1974-, et al.
(författare)
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RISEnergy: Roadmaps for energy innovation in Sweden through 2030
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- RISE Research Institutes of Sweden is a group of research and technology organisations. RISE is a leading innovation partner working global cooperation with academia, enterprise and society to create value, growth and competitiveness through research excellence and innovation.In the area of Energy, RISE has developed innovation Roadmaps covering:Energy Efficient TransportElectric Power SystemEnergy Efficient and Smart BuildingsSustainable Thermal ProcessesEfficient Energy Use in IndustryDecarbonisation of Basic IndustriesThese Roadmaps describe development pathways for technologies, non-technical elements (market design, user behaviours, policies, etc.) and key actors that deliver on a plausible, desirable vision for each respective innovation area in 2030. These Roadmaps are intended to support RISE’s strategic planning and development, but should be relevant reading for anyone interested in energy innovation in Sweden.
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| 3. |
- Hedenstedt, Anders, et al.
(författare)
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Korrosion vid lagring av slagg från avfallsförbränning : Lagringens påverkan på miljöegenskaper samt möjlighet att återvinna metaller
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Restprodukter från avfallsförbränning i rosterpannor utgör i regel 18-25 % (våt vikt) av den ingående avfallsmängden. Av restprodukterna utgörs huvuddelen av slagg/bottenaska (c:a 80 % våt vikt). Slaggen innehåller betydande mängder metaller som bedöms uppgå till c:a 7–15 % magnetiskt skrot och 1-2% icke- magnetiskt skrot. Slaggen lagras vanligen utomhus på en avfallsanläggning för att den ska torka samt för att metaller ska fastläggas. Detta är en förutsättning för att slaggen sedan ska kunna användas i olika anläggningsapplikationer. Efter lagringen sorteras slaggen för utvinning av metaller samt för att erhålla så kallat slaggrus som kan användas som konstruktionsmaterial. Vid lagring av slagg korroderar metallerna som finns i slaggen. Om korrosionen begränsas kan utvinningen av metaller öka och miljöegenskaperna hos slaggruset eventuellt förbättras. Detta skulle kunna minska behovet av brytning av både metaller och naturgrus. Tidigare laboratorieförsök visar att korrosionshastigheten i våt slagg är hög för att sedan avta när slaggen torkar. När slaggen utsätts för väta igen ökar korrosionshastigheten kraftigt. I detta projekt undersöktes vilken betydelse olika lagringsförfaranden har för korrosionen av metaller i slaggen samt dess miljöegenskaper. Försöket utfördes på Tagene avfallsanläggning under c:a 7 månader. Försöksuppställningen omfattade fem mindre slagghögar som representerade olika lagringsförfaranden – lagring med respektive utan väderskydd, med respektive utan omblandning samt tidigarelagd metallsortering. Korrosionshastigheten med avseende på stål- respektive aluminiumelektroder registrerades kontinuerligt och genom regelbunden omkoppling erhölls mätresultat för respektive lagringsförfarande för vart femte dygn. För verifiering av resultaten från korrosionsmätningarna utfördes också en visuell analys av korrosionselektroderna efter avslutat försök. Provuttag gjordes från färsk slagg samt från respektive hög efter c:a 3,5 och 7 månaders lagring. Proverna analyserades med avseende på totalthalt och utlakning. Dessutom gjordes provuttag efter 6 månader på olika djup i ett par av högarna för bestämning av hur den syraneutraliserande kapaciteten varierar lokalt. Resultaten från projektet visar att lagringsförfarandet inte har någon väsentlig påverkan vare sig med avseende på korrosionen av metaller i slaggen eller utlakningen av ämnen från slaggen. Det finns således ingen anledning att frångå det lagringsförfarande som vanligen tillämpas med avseende på slagg, det vill säga utomhus utan omblandning. Däremot bör utsortering av metaller göras så tidigt som möjligt under lagringsperioden eftersom korrosionshastigheten för åtminstone järn är stabilt hög redan efter en månads lagring.
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| 4. |
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| 5. |
- Hjörnhede, Anders, 1968, et al.
(författare)
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Erosion-corrosion of laser and thermally deposited coatings exposed in fluidised bed combustion plants
- 2006
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Ingår i: Materials and Corrosion. ; 57:4, s. 307-322
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Tidskriftsartikel (refereegranskat)abstract
- Coated steel tubes were exposed in two power plants (CFB and PFBC) fired with wood chips and coal with a small addition of olive seeds, respectively. Laser coating and two thermal spray techniques were used. The samples in the PFBC plant were immersed in the fluidising bed at material temperatures 450 °C and 400 °C. The exposure lasted for a total time of 8089 h. In the CFB plant a probe at the cyclone entrance had a material temperature of 630 °C for the first 2100 h and then 480 °C for 920 h. The material wastage was determined from tube cross-sections. The corrosion products and deposits were analysed by SEM/EDX, Auger spectroscopy, XPS and XRD. Cobalt based coatings show the best performance in both plants, while nickel based coatings are very sensitive to erosion but resistant to a corrosive atmosphere. The totally degraded chromium carbide containing coating in the CFB plant shows that the degree of corrosion is much larger in this environment. The same coating was excellent in the fluidised bed due to its high erosion resistance. The material wastage is independent of the deposition method. The coating technicques had no significant effect on the spallation behaviour.
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| 6. |
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| 7. |
- Henderson, Pamela, et al.
(författare)
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Combating corrosion in biomass and waste-fired plant
- 2010
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Ingår i: 9th Liege conference on Materials for Advanced Power engineering 2010. - : Forschungszentrum Jülich GmbH. - 9783893366859 ; , s. 986-999
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Konferensbidrag (refereegranskat)abstract
- Many biomass- or waste-fired plants have problems with high temperature corrosion especially if the steam temperature is greater than500°C. An increase in the combustion of waste fuels means that an increasing number of boilers have had problems. Therefore, there is great interest in reducing the costs associated with high temperature corrosion and at the same time there exists a desire to improve the electrical efficiency of a plant by the use of higher steam temperatures. Assuming that the fuel is well-mixed and that there is good combustion control, there are in addition a number of other measures which can be used to reduce superheater corrosion in biomass and waste fired plants, and these are described in this paper. These include the use of fuel additives, specifically sulphur-containing ones; design aspects like placing superheaters in less corrosive positions in a boiler, using tube shielding, a wider pitch between the tubes; operational considerations such as more controlled soot-blowing and the use of better materials.
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| 8. |
- Henderson, Pamela, et al.
(författare)
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Preliminary experience with material testing at the oxyfuel pilot plant at Schwarzepumpe
- 2010
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Ingår i: 9th Liege conference on Materials for Advanced Power engineering 2010. - : Forschungszentrum Jülich GmbH. - 9783893366859 ; , s. 1244-1259
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Konferensbidrag (refereegranskat)abstract
- Several material related issues may arise from oxyfuel combustion of coal due to the presence of CO2 but also as an effect of the partial recirculation of the flue gas. Two examples are increased corrosion and carburisation which may limit steam data, hence limiting the efficiency.A number of corrosion tests, in both conventional air-firing and oxyfuel mode, have been made in Vattenfalls 30 MW oxyfuel pilot plant located in Schwarze Pumpe, Germany. Internally cooled corrosion probes, equipped with ferritic, austenitic, super austenitic steels as well as Ni-based and FeCrAl alloys, simulating superheaters, economisers and air preheaters were exposed for up to 1500 hrs.The analyses show an indication of higher material wastage in oxyfuel compared to air combustion especially at the lower exposure temperatures. This may be due to increased sulphur concentration in corrosion front, increased heat flux, carburisation or other preciptate formations on austenitic steels and Ni-based alloys.
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| 9. |
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| 10. |
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| 11. |
- Hjörnhede, Anders, 1968
(författare)
-
Erosion - Corrosion Resistance and Adhesion of Laser and Thermally Deposited Coatings in Fluidised Beds
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- High temperature erosion - corrosion is the major source for degradation of components such as heat exchangers, tubes, cyclones and water walls used in Fluidised Bed Combustion (FBC) plants. By coating the exposed components with a protective material, the degradation rate can be decreased. The aim of this work was to determine the erosion - corrosion resistance of coatings deposited with the arc-spray, High Velocity Oxy Fuel (HVOF) and laser techniques. The erosion - corrosion tests have been performed in three different power plants; one Circulating Fluidised Bed (CFB) plant fired with biomass, one Multi Bed Combustion (MBC) plant fired with a mixture of coal and biomass and one Pressurised Fluidised Bed Combustion (PFBC) plant fired with coal. The erosion - corrosion resistance of coatings has also been examined in one laboratory jet nozzle test rig and one fluidised bed test rig. Further, the adhesion strength of coatings deposited on substrates of a low-alloyed steel (1Cr0.5Mo) has been tested. A number of commercially available coating qualities have been used in this study. The reference material is the Fe-based Metcoloy 2 coating, which was deposited with all the three methods available. The other coatings can be divided into Ni-based, Co-based, carbide - containing and Fe-based. Under active - service conditions Co-based coatings show the best overall performance. It is suggested that the erosion resistance is partly due to the presence of carbide rich phases dispersed in the coating. The softer Ni based coatings are generally more subjected to erosion. The corrosion resistance of Fe-based coatings is poor at higher temperatures in more corrosive environments. Chromium carbide - containing coatings are excellent in the coal fired erosive environment but degrade severely in the biomass fired plants showing that stable hard phases, such as carbide, at the exposure temperature decrease the degradation rate. Tungsten and Ti-carbide containing coatings suffer from severe degradation in all environments. The coated samples were subjected to erosion- corrosion in a jet nozzle rig in air at 520ºC or 550ºC. Compared to a solid 304L steel (Fe19Cr10Ni), the erosion - corrosion resistance of the coatings tested (Fe-based, Ni-based and carbide - containing) is higher. The oxides formed on the eroded area of the Metcoloy 2 coating are 10 - 60 times thicker than those formed on the non - eroded area. Consequently, erosion has increased the oxide growth rate. The increased oxide thickness on the eroded areas is due to the formation of cracks and pores in the oxide scale. These will enhance the inward transport of molecular oxygen through the oxide layer to the oxide/metal interface where the metal phase is oxidised. Erosion - corrosion tests performed in the fluidised bed test rig at 550°C in air shows that the erosion resistance of thermally sprayed coatings is higher in comparison to laser deposited coatings. The use of acoustic emission for determining the adhesion strength of the coatings proved to be successful and more reliable than the traditional four point bending test with a subsequent metallographic examination. HVOF sprayed coatings start to delaminate at a strain of about 1%, arc sprayed at a strain of about 1.4 2% while laser deposited coatings did not delaminate for strains up to 15%. However, by increasing the splat size in the arc sprayed coatings the strain at which delamination occurred was increased to a bout 10%.
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| 12. |
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| 13. |
- Jones, Frida, et al.
(författare)
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Down-time corrosion in boilers
- 2016
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Ingår i: Fuel processing technology. - : Elsevier. - 0378-3820 .- 1873-7188. ; 141, s. 276-284
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Tidskriftsartikel (refereegranskat)abstract
- Down-time corrosion can occur on boiler surfaces, e.g. furnace walls, superheaters, or economizers that are covered with hygroscopic deposits, when the temperature drops under 100 °C. This scenario takes place when a boiler is shut-down for cleaning, maintenance, or other reasons, such as unplanned shut-downs. Initially, the dry deposits will absorb moisture from the surrounding air, potentially creating a corrosive environment. After this, corrosive acids can form in the deposits. In this study modified online-corrosion probes were used in combination with deposits taken from 6 different boilers at various locations (for example, from the furnace, the superheater, and the economizer), where the fuels have been waste, demolition wood or biomass. The deposits were ground and dried in an oven at 160 °C for several hours before exposed to a moist environment (RH 65%) during online measuring of the corrosion rate and the pitting activity. Four types of alloys were tested: low-alloy ST45.8-steel, 9% Cr ferritic P91-steel, austenitic stainless steel 304L, and Ni-based super Alloy 625. The results for ST45.8 show that in biomass boilers a corrosion rate from negligible values up to 0.7 mm/year can be reached within a week, while waste-fired boilers can have rates as high as 1.8 mm/year. Furthermore, for some samples from waste-fired boilers show a high pitting activity already after 24 h. The tests with the P91-steel show values up to 0.16 mm/year, for samples from different locations in the boiler. For 304L and Alloy 625 the down-time corrosion was negligible even after a two-week exposure. The ability to follow the down-time corrosion online has provided data that show that even though thought to be negligible, the risk of down-time corrosion is of significance, especially if the fuel is waste. Also, even if the initial corrosion rate is low, it increases during the first 24 h due to the exposure to moist environment, motivating immediate cleaning of the boilers after shut-down, especially on surfaces of lower steel quality.
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| 14. |
- Ström, Henrik, 1981, et al.
(författare)
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Experimental and Numerical Investigations of Ash Behaviour in Fixed-Bed Combustion of Woody Biomass Pellets
- 2017
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Ingår i: Proceedings of the Nordic Flame Days 2017, Stockholm, Sweden.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Combustion of woody biomass in a fixed-bed configuration could play an important role in the development of small-scale combined-heat-and-power solutions, such as externally-fired micro-gas turbines. However, many challenges still remain with regard to the complexity of maintaining high availability with an acceptable fuel flexibility, as ash transformations in the fuel bed can cause serious problems for the robustness of the process as well as for downstream components. In this work, fixed-bed combustion of two woody biomasses of different ash contents is studied experimentally and numerically in an attempt to advance the understanding of ash-related disturbances. A mathematical model for fixed-bed conversion of biomass is extended to account for ash transformations on both the single-pellet level and the bed level, and the predictions from this model are assessed against the experimental results. The agreement between simulations and experiments is good for low air-flow rates, whereas additional considerations are needed for air-flow rates closer to the stoichiometric limit. Although there was no catastrophic slagging observed in the experiments, the capabilities of the model to describe effects of such slagging, down to only slightly reduced combustion rates due to milder ash transformations, are confirmed by the simulations.
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| 15. |
- Ström, Henrik, 1981, et al.
(författare)
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Experimental and Numerical Investigations of Ash Behaviour in Fixed-Bed Combustion of Woody Biomass Pellets
- 2018
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Ingår i: Industrial Combustion Journal. - 2075-3071.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Combustion of woody biomass in a fixed-bed configuration could play an important role in the development of small-scale combined-heat-and-power solutions, such as externally-fired micro-gas turbines. However, many challenges still remain with regard to the complexity of maintaining high availability with an acceptable fuel flexibility, as ash transformations in the fuel bed can cause serious problems for the robustness of the process as well as for downstream components. In this work, fixed-bed combustion of two woody biomasses of different ash contents is studied experimentally and numerically in an attempt to advance the understanding of ash-related disturbances. A mathematical model for fixed-bed conversion of biomass is extended to account for ash transformations on both the single-pellet level and the bed level, and the predictions from this model are assessed against the experimental results. The agreement between simulations and experiments is good for low air-flow rates, whereas additional considerations are needed for air-flow rates closer to the stoichiometric limit. Although there was no catastrophic slagging observed in the experiments, the capabilities of the model to describe effects of such slagging, down to only slightly reduced combustion rates due to milder ash transformations, are confirmed by the simulations.
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| 16. |
- Talus, Annika, et al.
(författare)
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Effect of Lead Content in Used Wood Fuel on Furnace Wall Corrosion of 16Mo3, 304L and Alloy 625
- 2017
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Ingår i: Oxidation of Metals. - : Springer Science and Business Media LLC. - 0030-770X .- 1573-4889. ; , s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Corrosion of furnace wall tubes is a problem often caused by the use of corrosive fuels. The relatively high contents of lead, zinc, alkali metals and chlorides in these fuels are believed to contribute to the corrosion. Initial corrosion as a function of lead content in a wood-based fuel was studied for three materials: 16Mo3, 304L and Alloy 625. The materials were exposed for 8 h in a laboratory combustion test rig at a position resembling furnace wall conditions. The metal temperatures investigated were 350 and 400 °C. Increasing the lead content in the fuel or the temperature accelerated the corrosion rate of 16Mo3. It is proposed that lead and lead oxides in deposits react with iron chloride to form lead chloride, which when combined with alkali chlorides results in a very corrosive deposit containing low melting salt mixtures. Negligible corrosion was observed for 304L and Alloy 625.
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| 17. |
- Viklund, Peter, et al.
(författare)
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Corrosion of superheater materials in a waste-to-energy plant
- 2013
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Ingår i: Fuel processing technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 105:SI, s. 106-112
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Tidskriftsartikel (refereegranskat)abstract
- A major drawback when generating electricity from waste-fired boilers is the rapid corrosion of critical components such as superheater tubes. In this work a number of commonly-used superheater materials have been exposed on internally cooled probes in a waste-fired grate boiler. The investigated materials are the ferritic steel 13CrMo44, the ferritic-martensitic steel HCM12A, the austenitic steels Super 304, 317L and Sanicro 28, and the nickel-base alloys Hastelloy C-2000 and Inconel 625. Short-term exposures (3 h) for analysis of deposit composition and initial corrosion, as well as long-term exposures (1550 h) to investigate corrosion rates and corrosion characteristics have been made. Analysis revealed a deposit dominated by CaSO4, KCl and NaCl, but also appreciable amounts of low melting salt mixtures such as ZnCl2-KCl, PbCl2-KCl, FeCl2-KCl and NaCl-NiCl2. Metal loss measurements showed unacceptably high corrosion rates for 13CrMo44, HCM12A and Super 304. The corrosion attack for these alloys was manifested by the formation of mixed metal chloride/metal oxide scales. A different type of behaviour was seen for the higher alloyed austenitic steels and nickel-base alloys, which were able to form a chromium-enriched oxide next to the metal. However, these alloys suffered from some localised pitting attack. The behaviour is explained by oxide dissolution in the molten salts that are present in the deposit.
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| 18. |
- Viklund, Peter, et al.
(författare)
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Effect of sulphur containing additive on initial corrosion of superheater tubes in waste fired boiler
- 2009
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Ingår i: Corrosion Engineering, Science and Technology. - 1478-422X .- 1743-2782. ; 44:3, s. 234-240
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Tidskriftsartikel (refereegranskat)abstract
- The major drawback to generating electricity from waste fired boilers is the rapid corrosion of superheaters which increases the maintenance costs. Within the last few years, it has been shown that additions of ammonium sulphate to biomass fired boilers decrease the corrosion tendencies. This paper reports on the effects of ammonium sulphate on corrosion in a waste fired CFB boiler. Air cooled probes were exposed at a position corresponding to the one of superheater tubes. The probe temperature was 500 degrees C, corresponding to a steam temperature of similar to 450 degrees C. Both the austenitic steel EN1.4301 (Fe-18Cr-9Ni) and the low alloyed ferritic steel EN1.7380 (Fe-2.25Cr-1Mo) were tested. During exposure, the concentration of alkali chlorides in the flue gas was measured and a decrease was observed when adding ammonium sulphate. After 4 h of exposure, the probes were removed for detailed analysis with SEM-EDS, TOF-SIMS and XRD. The sides of the tubes facing the flue gas were covered with a calcium rich deposit, while relatively more sodium and potassium were present on the lee side. The results also show that ammonium sulphate shifted the deposit composition from chloride rich and highly corrosive, to one significantly less corrosive and dominated by sulphates of sodium, potassium and calcium. Metallography shows a marked difference in corrosion attack between the two steels. Iron chlorides accumulate at the metal/oxide interface of the ferritic steel, while the amounts of iron chlorides were significantly lower in the austenitic steel. These results indicate that ammonium sulphate has the potential to reduce corrosion in waste fired boilers and that austenitic stainless steels are more likely to resist corrosion in these environments than low alloyed ferritic steels.
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