Abstract
One future objective for coal-fired power generation is to develop advanced ultrasupercritical (A-USC) boilers that incorporate oxy-firing to facilitate carbon capture. The steam condition goals of 760°C/34.5 MPa will require major materials changes throughout the boiler, including Ni-base alloys in the hottest sections. Solution hardened alloys such as 740 and 282 are needed to meet the strength requirements for 760°C. In previous work, little difference in corrosion rate was found between air- and oxy-firing for alloy 740 at 600°-800°C so laboratory testing focused on the “worst case” oxy-firing conditions with higher CO2, H2O and SO2 than expected with air-firing. Model alloys were made to investigate the roles of Cr, Al, Ti, Co and Mo on the fireside corrosion behavior. Exposures conducted for 500h at 700° and 800°C found that Al and Ti additions typically reduced the extent of attack under these conditions. As expected, the alloy Cr content had a substantial effect between 18 and 22%. Additions of 4% and 8%Mo to Ni-20Cr-(0-20)Co alloys increased the metal loss at 800°C and Ni-20Cr-20Co-(0-8%)Mo showed the highest attack at 700°C. The much higher attack of alloy 282 at 800°C can likely be attributed to its lower Cr content compared to alloy 740, which was developed to have excellent fireside corrosion resistance.
Original language | English |
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Title of host publication | ASME 2014 Symposium on Elevated Temperature Application of Materials for Fossil, Nuclear, and Petrochemical Industries, ETAM 2014 |
Publisher | American Society of Mechanical Engineers |
ISBN (Electronic) | 9780791840740 |
DOIs | |
State | Published - 2017 |
Event | ASME 2014 Symposium on Elevated Temperature Application of Materials for Fossil, Nuclear, and Petrochemical Industries, ETAM 2014 - Seattle, United States Duration: Mar 25 2014 → Mar 27 2014 |
Publication series
Name | ASME 2014 Symposium on Elevated Temperature Application of Materials for Fossil, Nuclear, and Petrochemical Industries, ETAM 2014 |
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Conference
Conference | ASME 2014 Symposium on Elevated Temperature Application of Materials for Fossil, Nuclear, and Petrochemical Industries, ETAM 2014 |
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Country/Territory | United States |
City | Seattle |
Period | 03/25/14 → 03/27/14 |
Funding
ACKNOWLEDGMENTS The author would like to thank G. Garner, M. Howell, T. Lowe, H. Longmire, T. Jordan and D. Leonard for assistance with the experimental work and to D. Leonard for comments on the manuscript. The research was sponsored by the U.S. Department of Energy, Fossil Energy Advanced Research Materials Program (V. Cedro, project monitor).