Material Performance in Supercritical Water

Allen, Todd R.; Chen, Y.; Ren, X.; Sridharan, K.; Tan, L.; Was, Gary S.; West, E.; Guzonas, D.

doi:10.1016/b978-0-08-102865-0.00115-1

Cited by 5 publications

(7 citation statements)

References 53 publications

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“…Figure 12 shows the trend among available data sets for the 9%Cr alloys 41,43,48,66,67,80,[92][93][94][95] over the temperature range studied (360-800uC), and illustrates the considerable scatter among data for nominally the same alloy (e.g. approximately two orders of magnitude difference in k pm for T92 at 600uC).…”

Section: Mass-change Datamentioning

confidence: 99%

A review of the oxidation behaviour of structural alloys in steam

Wright¹,

Dooley²

2010

International Materials Reviews

286

177

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Section: Mass-change Datamentioning

confidence: 99%

A review of the oxidation behaviour of structural alloys in steam

Wright¹,

Dooley²

2010

International Materials Reviews

286

177

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“…Ni or Fe based) also affects the corrosion behaviour. Corrosion studies of Ni based alloys often show less weight gain than that seen for Fe based alloys, 21,32,33 partly due to the elevated concentrations of Cr, Nb and Al. However, Ni based alloys are susceptible to intergranular attack and pitting in SCW.…”

Section: Discussionmentioning

confidence: 99%

“…However, Ni based alloys are susceptible to intergranular attack and pitting in SCW. 33 As such, the potential for using an Fe based alloy as a coating material was investigated in this study. Al was added to a Fe–22Cr model alloy in order to improve the stability of the oxide scale in SCW, and Y was also added to improve oxide adhesion.…”

Section: Discussionmentioning

confidence: 99%

Characterisation of Fe–20Cr–6Al–Y model alloy in supercritical water

Huang

Guzonas

2014

Corrosion Engineering, Science and Technology

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MCrAlY (M5Fe, Ni or Co) alloys belong to a class of coating materials that provide corrosion and oxidation resistance to Fe or Ni based substrate alloys by forming a dense alumina layer on the surface. In order to assess its potential as a corrosion resistant coating on components in supercritical water cooled reactor core, a Fe-22Cr-6Al-0?6Y model alloy was tested in supercritical water (SCW) (500uC and 25 MPa) for over 6000 h. The long-term corrosion behaviour of samples with various surface preparation means was evaluated by measuring weight change per unit surface area and examining surface microstructure and oxide formation using scanning electron microscopy and X-ray diffraction. The results showed that surface preparation alone led to changes in weight gain as great as seven times. Finely polished surface allowed for more oxidation to take place in SCW, hence more weight change due to Fe 3 O 4 (and spinel) formation. Simple grinding with abrasive paper yielded the least and the most stable weight change while grit blasting had resulted in the greatest weight gain, probably due to the increased surface area and more oxygen inward diffusion. Comparing to other alloys tested under similar condition, the ground Fe-22Cr-6Al-0?6Y had the lowest weight change. Although not detected, the formation of Al 2 O 3 or an Al/Y modified Cr 2 O 3 superficial layer was likely the reason for such low weight change.

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“…Crack depth X-ray measurements at different temperatures revealed the activation energy of CCG (E a,λ ) to be within the range of 85-105 kJ/mol for stainless steel alloys [56]. Even though Inconel 650 is one of the most resistant alloys [57,58], it is reasonable to choose for safety purposes the lowest activation energy to estimate the evolution of flaws at the reactor wall during the continuous operation under SCWG conditions. By combining the power law of Equation ( 6), the time dependency of λ obtained in Equation ( 10), and the Arrhenius law in Equation ( 11), the creep CCG rate of the reactor walls can be fairly estimated at any temperature within the operating window of SCWG.…”

Section: Safety Considerations and Improvement Opportunitiesmentioning

confidence: 99%

Implications on Feedstock Processing and Safety Issues for Semi-Batch Operations in Supercritical Water Gasification of Biomass

Blasio

Salierno

Magnano³

2021

Energies

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Biomass with a large amount of moisture is well-suited to be processed by supercritical water gasification, SCWG. The precipitation of inorganics, together with char formation and re-polymerization, can cause reactor plugging and stop the process operations. When plugging occurs, sudden injections of relatively large mass quantities take place, influencing the mass flow dynamics significantly in the process. Reactor plugging is a phenomenon very well observed during SCWG of industrial feedstock, which hinders scale-up initiatives, and it is seldom studied with precision in the literature. The present study provides an accurate evaluation of continuous tubular reactor dynamics in the event of sudden injections of water. An interpretation of the results regarding water properties at supercritical conditions contributes to comprehending mass and heat transfer when plugging occurs. Experiments are then compared to SCWG of a biomass sample aiming to give key insights into heat transfer and fluid dynamics mechanisms that could help develop operational and control strategies to increase the reliability of SCWG. In addition, a simplified model is presented to assess the effect of material integrity on burst-event likelihood, which states that SCWG is safe to operate, at 250 bar and 610 °C, in tubular reactors made of 0.22 wall thickness-to-diameter ratio Inconel-625 with superficial microfractures smaller than 30 µm. We also suggest improvement opportunities for the safety of SCWG in continuous operation mode.

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Material Performance in Supercritical Water

Cited by 5 publications

References 53 publications

A review of the oxidation behaviour of structural alloys in steam

A review of the oxidation behaviour of structural alloys in steam

Characterisation of Fe–20Cr–6Al–Y model alloy in supercritical water

Implications on Feedstock Processing and Safety Issues for Semi-Batch Operations in Supercritical Water Gasification of Biomass

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