High temperature degradation in power plants and refineries

Furtado, H.C.; May, Iain

doi:10.1590/s1516-14392004000100015

Cited by 38 publications

(22 citation statements)

References 9 publications

(7 reference statements)

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“…The material constants adopted for calculations are summarised in Table 1. TABLE 1 Material constants adopted for calculations [2,[8][9][10][11][12] The coefficients of thermal expansion α for M 7 C 3 carbides and austenite γ for a temperature higher than 20°C were determined based on the relationships being described in the other papers [2,13,14]. The hardening module E e for austenite γ was adopted based on the hardening module for 17% Cr-36% Ni austenitic steel cast being saturated for 3 hours at 1100°C and cooled in water [2].…”

Section: Model Of Materials Microstructure and Propertiesmentioning

confidence: 99%

Numerical Modelling of Micro-Stresses in Carbonised Austenitic Cast Steel under Rapid Cooling Conditions

Tuleja

Zatorski

2017

Archives of Metallurgy and Materials

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The paper presents a method of the numerical modelling of micro-stresses in carbonised austenitic cast steel being developed during rapid cooling due to differences in the values of thermal expansion coefficients for this material phases -carbides and austenitic matrix. Micro-stresses are indicated as the main cause of crack initiation in the tooling elements of carburising furnaces being mainly made of austenitic cast steel. A calculation model of carbonised and thermally fatigued austenitic cast steel was developed based on the microstructure images obtained using light microscopy techniques and the phase composition evaluated with the X-ray diffraction method. The values of the stress tensor components and the reduced stress in the complex models of test material structure were determined numerically by the finite element method. The effort analysis was performed and the areas where development of cracks is to be expected were identified, which was experimentally confirmed.

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Section: Model Of Materials Microstructure and Propertiesmentioning

confidence: 99%

Numerical Modelling of Micro-Stresses in Carbonised Austenitic Cast Steel under Rapid Cooling Conditions

Tuleja

Zatorski

2017

Archives of Metallurgy and Materials

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“…For this reason we must consider the resistivity of the material as a tensor: , and will be the resistivity in the , and directions respectively. Madhi and Nagy provide an analytical description of the potential distribution produced by a current source in an anisotropic half space [Madhi & Nagy, 2011], (1) where is the electric potential at a given field point of special coordinates ( from a point current source injecting current with coordinates ( . is an integration constant that corresponds to the electric potential at some remote point which we assume to be negligible ( ).…”

Section: Directional Ac Potential Drop Measurementmentioning

confidence: 99%

“…Creep is one of the most serious high temperature damage mechanisms [Furtado & May, 2004]. Many conventional power stations are reaching the end of their design life.…”

Section: Introductionmentioning

confidence: 99%

A potential drop strain sensor for in-situ power station creep monitoring

Corcoran¹,

Cawley²,

Nagy³

2014

AIP Conference Proceedings

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Creep is a high temperature damage mechanism of interest to the power industry and at present lacks a satisfactory inspection technique. Existing material inspection techniques are extremely laborious while strain measurements rely on often infrequent off-load measurements. A quasi-DC directional potential drop technique has been suggested that is able to suppress the effects of permeability and is primarily sensitive to changes in resistivity and also the geometry that will develop through strain. The change in creep related resistivity is shown by an equivalent effective resistivity approach to be small at <2% change when compared to the >100% change in transfer resistance that occurs due to strain as observed in laboratory tests. A biaxial inversion is then presented and demonstrated on in-lab samples showing good performance. The result is a sensor that performs as a very robust high temperature strain gauge.

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“…In thermal units that use coal as a heat source, some mechanisms can lead to surface deterioration and other carbon steel components, reducing their lifespan. As already known, the main deterioration mechanisms in power plant boilers are creep damage, microstructural degradation, erosion by fly-ash and high-temperature fatigue, embrittlement, carburization, hydrogen damage, graphitization, thermal shock, liquid metal embrittlement, and high-temperature corrosion of various types [3][4][5] . These mechanisms are associated with long-term exposure to high-temperatures, strain generated by particle`s impact, and corrosive action of combustion products, which can be intensified due to high temperatures 5,6 .…”

Section: Introductionmentioning

confidence: 99%

Characterization of Fly Ash and a Protective Coating for Brazilian Thermal Power Plant Boilers

et al. 2020

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Thermoelectric power plants that use mineral coal show high wear in heat exchanger due to the action of several damage mechanisms associated with the impact of hard particles from the residue of burnt coal, the ashes. The employment of coatings should be given into consideration particularly for critical components, which are subject to severe erosive conditions is one of the solutions. However, the choice of material will depend on several factors, including the properties of aggressive ashes. This paper aims to characterize ashes generated by a Brazilian coal-based power plant and a FeCrNbNi-based metallic coating obtained by the electric arc spraying process. No trace of sulfur content was found in fly ashes and it was defined that wear is mainly related to the impact and energy of hard particles are the leading causes of degradation in coal-fired boiler equipment. According to the assessment, applied coating showed (5 ± 2)% by volume of pores and cracks, with 1.6% of oxides after the spraying process and hardness 35% greater than ash particles. Preliminary results in field operation suggest that the material showed relatively low wear compared to the original substrate and showed great applicability in controlling material deterioration for this purpose.

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High temperature degradation in power plants and refineries

Cited by 38 publications

References 9 publications

Numerical Modelling of Micro-Stresses in Carbonised Austenitic Cast Steel under Rapid Cooling Conditions

Numerical Modelling of Micro-Stresses in Carbonised Austenitic Cast Steel under Rapid Cooling Conditions

A potential drop strain sensor for in-situ power station creep monitoring

Characterization of Fly Ash and a Protective Coating for Brazilian Thermal Power Plant Boilers

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