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Title: Effects of calcium in ash on the corrosion performance of Ni-based alloys in simulated oxy-fuel environment

Abstract

Increasing the efficiency of coal power plants requires raising the operating temperature above 650°C. However, coal ash can severely attack alloy materials at high temperature. For example, the corrosion rates of commercial Fe- and Ni-based alloys are generally greater than 2 mm/year at 750°C in the gas environment of oxy-fuel combustion. Thus, a critical study is needed to determine the effect of the constituents in the ash on corrosion and find an approach to reduce the corrosion rates in an ash-laden environment at high temperature. The role of CaO in the ash (typical of U.S. Western coal ash) has been investigated in laboratory exposure environments with various structural alloys. Detailed results are presented on weight change, scale thickness, internal penetration, microstructural characteristics of corrosion products, and the cracking of scales for the alloys after exposure at 750°C. The thermal stability of K3Al(SO4)3 under the environment of oxy-fuel combustion was determined by thermogravimetric analysis and differential thermal analysis. The reaction of this low melting temperature salt with the CaO-containing ash is discussed. In addition, we performed synchrotron nanobeam X-ray analysis to study the phase and chemical composition of the oxide layers on the alloy surface. Results from these studies are usedmore » to address the role of CaO in ash in the long-term corrosion performance of alloys.« less

Authors:
ORCiD logo; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Fossil Energy (FE); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1391827
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Fuel; Journal Volume: 178; Journal Issue: C
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Ash corrosion; CaO; Long term test; Oxy-fuel

Citation Formats

Zeng, Z., Natesan, K., Cai, Z., and Rink, D. L. Effects of calcium in ash on the corrosion performance of Ni-based alloys in simulated oxy-fuel environment. United States: N. p., 2016. Web. doi:10.1016/j.fuel.2016.02.077.
Zeng, Z., Natesan, K., Cai, Z., & Rink, D. L. Effects of calcium in ash on the corrosion performance of Ni-based alloys in simulated oxy-fuel environment. United States. doi:10.1016/j.fuel.2016.02.077.
Zeng, Z., Natesan, K., Cai, Z., and Rink, D. L. Mon . "Effects of calcium in ash on the corrosion performance of Ni-based alloys in simulated oxy-fuel environment". United States. doi:10.1016/j.fuel.2016.02.077.
@article{osti_1391827,
title = {Effects of calcium in ash on the corrosion performance of Ni-based alloys in simulated oxy-fuel environment},
author = {Zeng, Z. and Natesan, K. and Cai, Z. and Rink, D. L.},
abstractNote = {Increasing the efficiency of coal power plants requires raising the operating temperature above 650°C. However, coal ash can severely attack alloy materials at high temperature. For example, the corrosion rates of commercial Fe- and Ni-based alloys are generally greater than 2 mm/year at 750°C in the gas environment of oxy-fuel combustion. Thus, a critical study is needed to determine the effect of the constituents in the ash on corrosion and find an approach to reduce the corrosion rates in an ash-laden environment at high temperature. The role of CaO in the ash (typical of U.S. Western coal ash) has been investigated in laboratory exposure environments with various structural alloys. Detailed results are presented on weight change, scale thickness, internal penetration, microstructural characteristics of corrosion products, and the cracking of scales for the alloys after exposure at 750°C. The thermal stability of K3Al(SO4)3 under the environment of oxy-fuel combustion was determined by thermogravimetric analysis and differential thermal analysis. The reaction of this low melting temperature salt with the CaO-containing ash is discussed. In addition, we performed synchrotron nanobeam X-ray analysis to study the phase and chemical composition of the oxide layers on the alloy surface. Results from these studies are used to address the role of CaO in ash in the long-term corrosion performance of alloys.},
doi = {10.1016/j.fuel.2016.02.077},
journal = {Fuel},
number = C,
volume = 178,
place = {United States},
year = {Mon Aug 01 00:00:00 EDT 2016},
month = {Mon Aug 01 00:00:00 EDT 2016}
}