The potential for using high chromium ferritic alloys for hydroprocessing reactors

Antalffy, Les; Chaku, Pran N; Canonico, D.A.; Pfeifer, Jeff A; Alcorn, Douglas G

doi:10.1016/s0308-0161(02)00090-x

Cited by 9 publications

(3 citation statements)

References 3 publications

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“…The creep resistant steel 2.25Cr-1Mo-0.25V was introduced as a further development of the conventional alloy 2.25Cr-1Mo in the early 1990s. Compared to its predecessor, the V-modified version possesses several advantages such as increased strength at elevated temperatures, improved resistance to hydrogen attack and temper embrittlement as well as sufficient toughness [1][2][3][4][5]. On account of these benefits, 2.25Cr-1Mo-0.25V is often used for heavy wall pressure vessels for high temperature hydrogen service in power stations as well as in the petroleum and chemical industry, e.g.…”

Section: Introductionmentioning

confidence: 99%

On the impact of post weld heat treatment on the microstructure and mechanical properties of creep resistant 2.25Cr–1Mo–0.25V weld metal

et al. 2021

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Creep resistant low-alloyed 2.25Cr-1Mo-0.25V steel is typically applied in hydrogen bearing heavy wall pressure vessels in the chemical and petrochemical industry. For this purpose, the steel is often joined via submerged-arc welding. In order to increase the reactors efficiency via higher operating temperatures and pressures, the industry demands for improved strength and toughness of the steel plates and weldments at elevated temperatures. This study investigates the influence of the post weld heat treatment (PWHT) on the microstructure and mechanical properties of 2.25Cr-1Mo-0.25V multi-layer weld metal aiming to describe the underlying microstructure-property relationships. Apart from tensile, Charpy impact and stress rupture testing, micro-hardness mappings were performed and changes in the dislocation structure as well as alterations of the MX carbonitrides were analysed by means of high resolution methods. A longer PWHT-time was found to decrease the stress rupture time of the weld metal and increase the impact energy at the same time. In addition, a longer duration of PWHT causes a reduction of strength and an increase of the weld metals ductility. Though the overall hardness of the weld metal is decreased with longer duration of PWHT, PWHT-times of more than 12 h lead to an enhanced temper resistance of the heat-affected zones (HAZs) in-between the weld beads of the multi-layer weld metal. This is linked to several influencing factors such as reaustenitization and stress relief in the course of multi-layer welding, a higher fraction of larger carbides and a smaller grain size in the HAZs within the multi-layer weld metal.

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Section: Introductionmentioning

confidence: 99%

On the impact of post weld heat treatment on the microstructure and mechanical properties of creep resistant 2.25Cr–1Mo–0.25V weld metal

et al. 2021

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“…because of their superior mechanical properties at elevated temperature. For refining industries, application of 9Cr-1Mo-V steels to hydroprocessing reactors has been discussed [3] and the guidelines to apply 9Cr-1Mo-V steels in the oil refinery services were provided in API TR 938-B [4]. Fig.…”

Section: Introductionmentioning

confidence: 99%

Development of Pressure Vessels Made of 9Cr-1Mo-V Steels for High-Temperature Processes in Refining Industries

Nakanishi

Ikeuchi

Terada

et al. 2014

Volume 6B: Materials and Fabrication

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Due to the increasing demands for light oil in newly industrializing countries and depletion of conventional oil resources, upgrading of heavy oil and coal-to-liquid processes have been a focus in recent years. The efficiency of these processes depends on temperature and pressure conditions, where a higher temperature, around 500ºC, is likely to be used. However, 2 1 / 4 Cr-1Mo-V steels which have been widely used for heavy-wall pressure vessels for many years cannot be applied to a high temperature process around 500ºC since the design temperature of this material is limited to 482ºC by ASME Code Section VIII, Division 2 [1].On the other hand, 9Cr-1Mo-V steels (Grade 91), which has an excellent performance at high temperature in mechanical properties and hydrogen resistance, has been used for tubing and piping materials in power industries and it can be a candidate material for the high temperature processes. However it has not been used for pressure vessels in refining industries.In order to manufacture heavy-wall pressure vessels using 9Cr-1Mo-V steels, essential techniques including manufacture of large forged shell rings, thick wall welding and overlay welding have been developed.

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“…On the other hand, at temperatures below 149°C hydrogen embrittlement can occur during hydrogenation reactors shutdown cycle. Hydrogen dissolved in the wall reactor at normal temperature operation is not able to diffuse out of steel if it is cooled too rapidly to permit outgassing [4].…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Trap on the Microstructure of Cr-Mo Type Steels

Lemus

Rodrigues

Santos

et al. 2009

DDF

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Microstructure influence on hydrogen trapping in a Cr-Mo type steels −2.25Cr 1Mo and 2.25Cr 1Mo 0.25V− was studied by means of electrochemical permeation test, thermal desorption spectrometry, scanning and transmission electron microscopy analysis. Both steels, used in hydrogenation reactors, in as received and artificial aged conditions exhibit a bainitic microstructure with CrxMoy and CrxMoyVz carbides finely dispersed. The hydrogen diffusivity for the 2.25Cr-1Mo-0.25V is lower than 2.25Cr-1Mo due to its higher carbide precipitation. At aged conditions TDS on samples cathodically charged with hydrogen showed an increase on the hydrogen trapping capacity for 2.25Cr-1Mo and a reduction for the vanadium modified steel, compared with the as-received state.

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The potential for using high chromium ferritic alloys for hydroprocessing reactors

Cited by 9 publications

References 3 publications

On the impact of post weld heat treatment on the microstructure and mechanical properties of creep resistant 2.25Cr–1Mo–0.25V weld metal

On the impact of post weld heat treatment on the microstructure and mechanical properties of creep resistant 2.25Cr–1Mo–0.25V weld metal

Development of Pressure Vessels Made of 9Cr-1Mo-V Steels for High-Temperature Processes in Refining Industries

Hydrogen Trap on the Microstructure of Cr-Mo Type Steels

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