Simulating the implications of oxide scale formations in austenitic steels of ultra-supercritical fossil power plants

Yeo, Wei Hong; Fry, A T; Ramesh, S.; Mohan, Rakesh; Liew, H.L.; Inayat-Hussain, Jawaid I.; Purbolaksono, J.

doi:10.1016/j.engfailanal.2014.03.011

Cited by 14 publications

(10 citation statements)

References 5 publications

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“…This section discusses the methods used in the literature 150,152,153 to analyze material oxidation behavior. To analyze the temperatures and scale thickness of oxidation in materials, a steady-state heat transfer theory and the data for the scale thicknesses are incorporated, which can obtain the results over a service time in the superheater/reheater tubes (eq 44):…”

Section: Materials Oxidation Model and Modeling Resultsmentioning

confidence: 99%

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A Review of the Numerical Modeling of Pulverized Coal Combustion for High-Efficiency, Low-Emissions (HELE) Power Generation

et al. 2021

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High-efficiency, low-emissions (HELE) coal-fired power plant technologies operate with a higher thermal efficiency of the steam cycle for coal-fired power generation, reducing CO2 emissions per unit energy generation. They represent some of the primary and intermediate solutions to the world’s energy security. Extensive numerical modeling efforts have been undertaken over the past several decades, which have increased our understanding of the technical problems in HELE boilers, including combustion and boiler performance optimization, ash deposition, and material problems at higher operating temperatures and pressures. Overall, the differences in the physical and chemical models, boiler performance, and ash deposition of oxy-fuel combustion in HELE boilers that recirculate CO2 and H2O in the boilers are also discussed in comparison with the combustion of coal in the air. This Review comprehensively summarizes the current research on numerical modeling to offer a better understanding of the technical aspects and provides future research requirements of HELE coal-fired boilers, including boiler performance optimization, ash deposition, and material problems. The effects of changes in the configuration and operating conditions are discussed, focusing on the optimization of boiler performance in aspects such as unburnt carbon and NOx emissions. The paper also reviews the retrofit and optimization of operating conditions and the burner geometry with the low-NOx coal combustion technologies necessary to operate the HELE power plants. In terms of ash deposition, the development of submodels, including particle sticking and impacting behaviors and their effects on the deposit growth predictions under different temperatures, are discussed. Numerical models of the material oxidation and creep in the austenitic and nickel-based alloys generally used in HELE conditions have been developed using the finite element method to predict the availability of advanced alloys and creep life in the actual service time of the boiler parts. The predictions of oxide scale growth and exfoliation on the steam-side and fire-side and the creep strength are analyzed. The review also identifies some further research requirements in numerical modeling to achieve the optimization of coal combustion processes and address the technical problems in advanced HELE power plant operations.

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Section: Materials Oxidation Model and Modeling Resultsmentioning

confidence: 99%

“…A specific procedure is available to determine the temperatures in materials and the oxide scale thicknesses using the FEM, 150,153 which can be used to analyze the oxide scale growth exfoliation phenomenon on the steam-and firesides.…”

Section: Materials Oxidation Model and Modeling Resultsmentioning

confidence: 99%

A Review of the Numerical Modeling of Pulverized Coal Combustion for High-Efficiency, Low-Emissions (HELE) Power Generation

et al. 2021

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“…[ 4 ] After a long‐term exposure in high‐temperature steam, FeCr alloys generally form an oxide scale with two layers. [ 5–7 ] Attributed to the different transport rate of cations on vacant sites and interstitial sites, various pores are formed within the oxide scale. [ 8 ] These pores would result in oxide spallation during the cooling process of power plant [ 9 ] and cause plugging, steam starvation, and local overheating of tubes.…”

Section: Introductionmentioning

confidence: 99%

The role of Cr atom in the early steam oxidation of Fe‐based alloys: An atomistic simulation

Jing

Liang

et al. 2020

Materials & Corrosion

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This study employed the density functional theory to capture the atomic‐level dissociation processes of steam and investigate the ions migration on Fe(001) and FeCr(001) surfaces, revealing the role of Cr atom in the early oxidation. Various coadsorption structures with different steam‐derived species have been systematically examined to find the most energetically favored surface site. The results showed that the steam dissociation on the alloy surface underwent two steps. First, H2O molecule on the top site was dissociated into OH group and H atom, which further combined with metal atoms on the bridge site and hollow site. Second, the OH group was decomposed into O and H atoms, which moved to two adjacent hollow sites and generated an oxide. On further oxidation, the Fe atom migrated outward and formed an outer Fe oxide, whereas the Cr oxide could only grow inward as O atom passed through oxide. It was found that the presence of Cr atom on the surface was thermodynamically beneficial, which could promote steam oxidation. The Cr atom could effectively block ion diffusion across the oxide scale and protect the underlying substrate from further oxidation. These results were in good agreement with experimental observation.

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“…[15] Numerous numerical simulations have been conducted to calculate the tube wall temperature of high temperature components. [16][17][18] Yeo et al [19] calculated the heat transfer coefficient on the tube surface by the empirical formulae, and the Ansys software was utilized to determine the tube wall temperature profiles. Because of the difficulty in describing the complex tube arrangements and gas thermal processes, few analytical studies conducted the research on the heat transfer of parallel U-tubes in detail.…”

Section: Introductionmentioning

confidence: 99%

Creep rupture life assessment of superheater tube with oxide formation in power plant

Jing

et al. 2020

Materials & Corrosion

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This paper proposes a method for predicting the creep rupture life of superheater tubes, considering the continuous increasing metal temperature and stress as a result of oxide formation. The steam-side oxide growth was assessed by the parabolic oxidation rate law, and the temperature profiles of superheater tubes was calculated combining the 3D computational fluid dynamics simulation and the 1D analytical models. Based on the estimated temperature and maximum elastic hoop stress, the parametric extrapolation technique was utilized to assess the creep rupture life. The validity of this method was confirmed by measuring the oxide thickness and the steam temperature in the field. The results found that T91 alloy in the steam outlet region and T23 alloy at the connection point was susceptible to creep rupture failure, which had the greatest cumulative damage and thickest oxide scale. The cumulative damage of superheater tubes varied significantly with tube count. Results suggested that replacement of the particular T91 alloy tubing section having the minimum creep rupture life with a better heat-resistant steel would avoid mechanical failure by creep for the subject boiler system.

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Simulating the implications of oxide scale formations in austenitic steels of ultra-supercritical fossil power plants

Cited by 14 publications

References 5 publications

A Review of the Numerical Modeling of Pulverized Coal Combustion for High-Efficiency, Low-Emissions (HELE) Power Generation

A Review of the Numerical Modeling of Pulverized Coal Combustion for High-Efficiency, Low-Emissions (HELE) Power Generation

The role of Cr atom in the early steam oxidation of Fe‐based alloys: An atomistic simulation

Creep rupture life assessment of superheater tube with oxide formation in power plant

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