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Alloy Selection for...
Alloy Selection for a Cofired Circulating Fluidized Bed Boiler Vortex Finder Application at 880 °c in a Complex Mixed Mode Corrosion Environment
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- Hagman, Henrik (författare)
- Umeå universitet,Institutionen för tillämpad fysik och elektronik
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- Lundberg, Mats (författare)
- KTH,Yt- och korrosionsvetenskap
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- Boström, Dan (författare)
- Umeå universitet,Institutionen för tillämpad fysik och elektronik
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(creator_code:org_t)
- 2017-11-02
- 2017
- Engelska.
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 31:11, s. 12857-12866
- Relaterad länk:
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https://urn.kb.se/re...
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visa fler...
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https://doi.org/10.1...
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https://urn.kb.se/re...
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Abstract
Ämnesord
Stäng
- X-ray diffraction and scanning electron microscopy (SEM) were used on a corroded industrial-scale circulating fluidized bed (CFB) boiler vortex finder (VF) 253MA alloy plate material to identify the dominating corrosion products and to enable a qualified selection of candidate alloys for the long-term, full-scale exposure study. Alloys 253MA, 310S, 800H/HT, Alloy DS, and Alloy 600 were chosen, and the alloy plates were exposed to the CFB boiler combustion atmosphere having an average temperature of approximately 880 °C, consisting of a moist globally oxidizing gas, burning hydrocarbons, CO2, CO, SO2, HCl, NH3, N2, alkali species, and erosive particles. The exposure times used in this study were 1750, 8000, 12000, and 16000 operating hours. After exposure, the alloy samples were cut, and cross-sections were dry-polished and analyzed with an SEM-backscatter electron detector (BSD) setup to quantify material loss and penetration depth of the corrosion attack. This work suggests two novel concepts: heavily affected depth (HAD) enabling quantitative evaluation of heavily degraded alloys and remaining serviceable metal thickness (RSMT) enabling the use of long-term corrosion data from one alloy to make rough service life estimations of other alloys exposed for significantly shorter periods. The findings of this work show that there is no simple correlation between the heavily affected depth of the alloy and the nickel, chromium, or iron content. Instead, there seem to be two successful alloy composition principles that work well for this application. Furthermore, the work shows that major improvements can be made in terms of both technical life-span and the cost-effectiveness of the VF application if the most appropriate alloy is selected. In this study, a replacement of the frequently used Alloy 253MA with Alloy 310S doubled the lifespan of full-scale VFs, reducing the average VF maintenance cost to half.
Ämnesord
- TEKNIK OCH TEKNOLOGIER -- Kemiteknik -- Korrosionsteknik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Chemical Engineering -- Corrosion Engineering (hsv//eng)
- TEKNIK OCH TEKNOLOGIER -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)
Nyckelord
- Boilers
- Combustion
- Corrosion
- Cost effectiveness
- Fluidized bed combustion
- Fluidized bed process
- Pulverized fuel fired boilers
- Scanning electron microscopy
- Vortex flow
- X ray diffraction
- Alloy compositions
- Circulating fluidized bed boiler
- Corrosion environments
- Corrosion products
- Electron detectors
- Long-term corrosion
- Quantitative evaluation
- Service life estimation
- Fluidized beds
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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