CA3230133A1 - Use of electrochemical interference material to mitigate stress corrosion cracking of ferritic steel under insulation - Google Patents
Use of electrochemical interference material to mitigate stress corrosion cracking of ferritic steel under insulation Download PDFInfo
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 85
- 239000010959 steel Substances 0.000 title claims abstract description 85
- 239000000463 material Substances 0.000 title claims abstract description 79
- 238000009413 insulation Methods 0.000 title claims abstract description 68
- 230000007797 corrosion Effects 0.000 title claims abstract description 19
- 238000005260 corrosion Methods 0.000 title claims abstract description 19
- 238000005336 cracking Methods 0.000 title claims abstract description 12
- 239000011490 mineral wool Substances 0.000 claims abstract description 21
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 13
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 13
- 239000011888 foil Substances 0.000 claims abstract description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 12
- 230000000116 mitigating effect Effects 0.000 claims abstract description 5
- 239000000758 substrate Substances 0.000 claims description 64
- 238000000034 method Methods 0.000 claims description 17
- 238000011084 recovery Methods 0.000 claims description 10
- 238000011065 in-situ storage Methods 0.000 claims description 8
- 239000004215 Carbon black (E152) Substances 0.000 claims description 6
- 238000000576 coating method Methods 0.000 claims description 6
- 229930195733 hydrocarbon Natural products 0.000 claims description 6
- 150000002430 hydrocarbons Chemical class 0.000 claims description 6
- 238000005253 cladding Methods 0.000 claims description 5
- 239000011248 coating agent Substances 0.000 claims description 5
- 238000010796 Steam-assisted gravity drainage Methods 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 4
- 239000000843 powder Substances 0.000 claims description 4
- 238000005507 spraying Methods 0.000 claims description 4
- 238000003384 imaging method Methods 0.000 claims description 3
- 238000002601 radiography Methods 0.000 claims description 3
- 238000009420 retrofitting Methods 0.000 claims description 3
- 238000011179 visual inspection Methods 0.000 claims description 3
- 238000002485 combustion reaction Methods 0.000 claims description 2
- 230000008569 process Effects 0.000 claims description 2
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- 238000012545 processing Methods 0.000 abstract description 3
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- 229910000975 Carbon steel Inorganic materials 0.000 description 5
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 230000000977 initiatory effect Effects 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 230000010287 polarization Effects 0.000 description 3
- 210000002268 wool Anatomy 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 239000010962 carbon steel Substances 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
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- 238000001764 infiltration Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
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- 230000002452 interceptive effect Effects 0.000 description 1
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- 150000003839 salts Chemical class 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
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- 238000012360 testing method Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N17/00—Investigating resistance of materials to the weather, to corrosion, or to light
- G01N17/006—Investigating resistance of materials to the weather, to corrosion, or to light of metals
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- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
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- Immunology (AREA)
- Pathology (AREA)
- Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
Abstract
The present disclosure relates to mitigating intergranular stress corrosion cracking (IGSCC) in ferritic steel pipes and vessels under mineral wool insulation, used applications in oil and gas or other industries, e.g., refining, upgrading, distribution, chemical plants, food processing plants, and other light and heavy industries, where mineral wool is being used, by leveraging the use of an interference material that can be foil or mesh composed, for example, of aluminum. Pipes or vessels composed of bare ferritic steel having residual stresses and where water ingress occurs into the mineral wool insulation and operating between 70 C and 200 C are at higher risk of IGSCC and thus the interference material located in between the ferritic steel and the insulation can help mitigate such challenges.
Description
USE OF ELECTROCHEMICAL INTERFERENCE MATERIAL TO MITIGATE STRESS
CORROSION CRACKING OF FERRITIC STEEL UNDER INSULATION
TECHNICAL FIELD
[001] The technical field generally relates to mitigating intergranular stress corrosion cracking (IGSCC) in insulated ferritic steel pipelines, pipes, fittings and vessels under insulation.
BACKGROUND
CORROSION CRACKING OF FERRITIC STEEL UNDER INSULATION
TECHNICAL FIELD
[001] The technical field generally relates to mitigating intergranular stress corrosion cracking (IGSCC) in insulated ferritic steel pipelines, pipes, fittings and vessels under insulation.
BACKGROUND
[002] In certain industries, such as oil sands extraction and thermal in situ hydrocarbon recovery operations among others, ferritic steel pipes, fittings and vessels having mineral wool insulation on the outside can undergo IGSCC. This can occur when the mineral wool comes in contact with water, for example. There are various corrosion issues related to insulated pipes and an improved technology is needed to help mitigate such corrosion issues, notably IGSCC challenges.
SUMMARY
The technology includes the use of an interference material that is provided to interfere with electrochemical potential of a ferritic steel substrate to inhibit IGSCC
when insulation in contact with the ferritic steel is exposed to water.
In some implementations, there is provided an intergranular stress corrosion cracking (IGSCC)-protected assembly, comprising: a ferritic steel substrate; insulation provided about the ferritic steel substrate for thermal insulation thereof; and an interference material located in between the ferritic steel substrate and the insulation, the interference material being selected to interfere with electrochemical potential of the ferritic steel substrate to inhibit IGSCC when the insulation is exposed to water.
In some implementations, the ferritic steel substrate is a pipe. In some implementations, the ferritic steel substrate is a vessel, optionally a pressure vessel. In some implementations, the insulation is mineral wool. In some implementations, the assembly includes an outer cladding. In some implementations, the interference material comprises aluminum. In some implementations, the interference material is aluminum. In some Date Recue/Date Received 2024-02-23 implementations, the interference material is provided as a foil. In some implementations, the interference material is provided as a mesh. In some implementations, the interference material is provided as a particulate, such as a powder or particles. In some implementations, the interference material is provided as a coating that is sprayed or coated onto the substrate and/or the insulation. In some implementations, the substrate has an uncoated ferritic steel outer surface, the interference material is selected to interfere with the electrochemical potential at temperatures between 70 C and 200 C, the assembly is configured to be located in an exterior environment exposed to water, and the substrate comprises residual stresses in the ferritic steel. In some implementations, the ferritic steel of the substrate is pipeline grade, piping grade, fitting grade and pressure vessel plate grade ferritic steel.
In some implementations, there is provided a method for mitigating intergranular stress corrosion cracking (IGSCC) of a ferritic steel substrate surrounded with insulation, comprising providing an interference material in between the ferritic steel substrate and the insulation, the interference material being composed of a material and configured to interfere with electrochemical potential of the ferritic steel substrate to inhibit IGSCC when the insulation is exposed to water.
In some implementations, the ferritic steel substrate is operated in a thermal in situ hydrocarbon recovery operation at temperatures between 70 C and 200 C. In some implementations, the thermal in situ hydrocarbon recovery operation comprises a Steam-Assisted Gravity Drainage (SAGD) process, a solvent-assisted recovery process, a solvent-dominated recovery process, or an in situ combustion process. In some implementations, providing the interference material comprises wrapping a distinct layer of the interference material around the ferritic steel substrate. In some implementations, providing the interference material comprises spraying or coating onto the substrate or the insulation. In some implementations, providing the interference layer comprises retrofitting an existing assembly, comprising: removing the insulation from the ferritic steel substrate, applying the interference material onto an outer surface of the ferritic steel substrate and/or onto the insulation, and then reinstalling insulation over the substrate. In some implementations, the method includes surveying a plurality of substrates to identify substrates that are at-risk for IGSCC, the surveying optionally comprising visual inspection, neutron backscatter, real-time radiography, real-time imaging, or infrared Date Recue/Date Received 2024-02-23
SUMMARY
The technology includes the use of an interference material that is provided to interfere with electrochemical potential of a ferritic steel substrate to inhibit IGSCC
when insulation in contact with the ferritic steel is exposed to water.
In some implementations, there is provided an intergranular stress corrosion cracking (IGSCC)-protected assembly, comprising: a ferritic steel substrate; insulation provided about the ferritic steel substrate for thermal insulation thereof; and an interference material located in between the ferritic steel substrate and the insulation, the interference material being selected to interfere with electrochemical potential of the ferritic steel substrate to inhibit IGSCC when the insulation is exposed to water.
In some implementations, the ferritic steel substrate is a pipe. In some implementations, the ferritic steel substrate is a vessel, optionally a pressure vessel. In some implementations, the insulation is mineral wool. In some implementations, the assembly includes an outer cladding. In some implementations, the interference material comprises aluminum. In some implementations, the interference material is aluminum. In some Date Recue/Date Received 2024-02-23 implementations, the interference material is provided as a foil. In some implementations, the interference material is provided as a mesh. In some implementations, the interference material is provided as a particulate, such as a powder or particles. In some implementations, the interference material is provided as a coating that is sprayed or coated onto the substrate and/or the insulation. In some implementations, the substrate has an uncoated ferritic steel outer surface, the interference material is selected to interfere with the electrochemical potential at temperatures between 70 C and 200 C, the assembly is configured to be located in an exterior environment exposed to water, and the substrate comprises residual stresses in the ferritic steel. In some implementations, the ferritic steel of the substrate is pipeline grade, piping grade, fitting grade and pressure vessel plate grade ferritic steel.
In some implementations, there is provided a method for mitigating intergranular stress corrosion cracking (IGSCC) of a ferritic steel substrate surrounded with insulation, comprising providing an interference material in between the ferritic steel substrate and the insulation, the interference material being composed of a material and configured to interfere with electrochemical potential of the ferritic steel substrate to inhibit IGSCC when the insulation is exposed to water.
In some implementations, the ferritic steel substrate is operated in a thermal in situ hydrocarbon recovery operation at temperatures between 70 C and 200 C. In some implementations, the thermal in situ hydrocarbon recovery operation comprises a Steam-Assisted Gravity Drainage (SAGD) process, a solvent-assisted recovery process, a solvent-dominated recovery process, or an in situ combustion process. In some implementations, providing the interference material comprises wrapping a distinct layer of the interference material around the ferritic steel substrate. In some implementations, providing the interference material comprises spraying or coating onto the substrate or the insulation. In some implementations, providing the interference layer comprises retrofitting an existing assembly, comprising: removing the insulation from the ferritic steel substrate, applying the interference material onto an outer surface of the ferritic steel substrate and/or onto the insulation, and then reinstalling insulation over the substrate. In some implementations, the method includes surveying a plurality of substrates to identify substrates that are at-risk for IGSCC, the surveying optionally comprising visual inspection, neutron backscatter, real-time radiography, real-time imaging, or infrared Date Recue/Date Received 2024-02-23
3 camera techniques and identifying wet insulation; optionally sampling identified wet insulation to further assess risk of IGSCC, optionally by assessing leachates from the wet insulation; optionally assessing residual stresses in the substrates to identify elevated residual stress locations that are at-risk for IGSCC; and for at-risk substrates, applying the interference material, optionally at the at-risk locations exposed to wet insulation and/or the elevated residual stress locations.
BRIEF DESCRIPTION OF DRAWINGS
[003] Fig 1 is a cross-sectional cut view of an example IGSCC-protected assembly including a tubular steel substrate, an interference layer, insulation, and an outer cladding.
BRIEF DESCRIPTION OF DRAWINGS
[003] Fig 1 is a cross-sectional cut view of an example IGSCC-protected assembly including a tubular steel substrate, an interference layer, insulation, and an outer cladding.
[004] Fig 2 is a longitudinal cut view of an example IGSCC-protected assembly showing insertion of an interference layer between a tubular steel substrate and insulation.
[005] Fig 3 is a cross-sectional cut view of an example insulated substrate and various forms of interference materials that can be used for application between the carbon steel and the insulation.
[006] Fig 4 is an example potentiodynamic polarization curve for steel.
DETAILED DESCRIPTION
DETAILED DESCRIPTION
[007] The present disclosure relates to mitigating intergranular stress corrosion cracking (IGSCC) in ferritic steel pipes and vessels that have mineral wool insulation on the outside, by providing an electrochemical interference material, such as aluminum, in between the ferritic steel surface and the mineral wool insulation. The interference material can be composed of a metal, such as zinc, aluminum or magnesium and their alloys, and can take the form of foil or mesh wrapped around the ferritic steel or of powder, particles spray coating or paint applied so as to be present in between the ferritic steel and mineral wool insulation. The interference material can be provided during initial installation or can be applied by retrofitting an installed pipe or vessel between the ferritic steel surface and the mineral wool insulation by opening up the insulation to expose the ferritic steel, applying the interference material, and enclosing the insulation back around the ferritic steel. In the context of the present disclosure, ferritic steel can be defined as steel that is composed of iron and carbon as the base, including additional elements that can also be Date Recue/Date Received 2024-02-23 added, and includes low-carbon steels, medium-carbon steels, high-carbon steels and low-alloy steels, that are commonly used in piping, vessels, tanks, pipeline, drums, heat exchangers, structural steels and equipment.
[008] The interference material can reduce IGSCC risks for the insulated pipes or vessels. It has been observed that, when contacted with water, mineral wool can cause IGSCC in the pipe or vessel. The intermediate interference material, such as aluminum, zinc, magnesium or their alloys, placed between the mineral wool and surface of the pipe or vessel can help disturb the electrochemical potential causing the stress corrosion cracking of the ferritic steel. It is noted that any material capable of interfering with the electrochemical potential of the steel structure can be used for the interference material at the operating conditions in question, and aluminum is a prime example. The interference material can also be selected for certain factors including cost, properties at the temperatures and humidity levels encountered for exterior pipe and vessel applications and/or applications (e.g., in certain oil sands processing facilities).
Materials that have corrosive properties at the target operating conditions or that convert to compounds (e.g., salts) that could cause issues can be avoided.
Materials that have corrosive properties at the target operating conditions or that convert to compounds (e.g., salts) that could cause issues can be avoided.
[009] Referring to Fig 1, an IGSCC-protected assembly 10 is shown and includes a ferritic steel substrate 12, such as a pipe, a pipeline, a vessel or an equipment, which is surrounded by insulation 14 and an outer cladding 16. The IGSCC-protected assembly 10 also has an interference material 18 provided in between the ferritic steel substrate 12 and the insulation 14. In this embodiment, the interference material 18 is in the form of a distinct layer, such as a mesh or foil. The ferritic steel substrate 12 can have a generally tubular structure having a passage 20, inner surfaces 22 and outer surfaces 24. Note that the ferritic steel structure can take a different shape that is not tubular or vessel shaped.
[0010] The interference material 18 can have various forms and can be composed of various materials. For example, the interference layer can be provided as a mesh, a foil, a continuous sheet, or other forms in contact with the outer surface 24 of the ferritic steel substrate 12. The interference material can be a relatively pure metal (e.g., Aluminum) or an alloy that can include two or more metal elements. The interference material 18 can provide a complete barrier between the insulation and the outer surface of the ferritic steel substrate, or it can have small apertures if it has a mesh or grid structure.
The interference material can also have various thicknesses depending on the design of the assembly.
Date Recue/Date Received 2024-02-23 When aluminum foil is used, it can be ultra-thin foil, standard foil, heavy-duty foil or extra-heavy-duty foil, thus having a thickness ranging from less than 10 microns to 30 microns or above. The interference material can be provided as a distinct pre-formed sheet that is then installed about the ferritic steel surface. When aluminum foil or mesh is used, it can be applied in a single layer or in multiple layers around the pipe, pipeline or vessel. When a mesh is used, the apertures can be small or large.
The interference material can also have various thicknesses depending on the design of the assembly.
Date Recue/Date Received 2024-02-23 When aluminum foil is used, it can be ultra-thin foil, standard foil, heavy-duty foil or extra-heavy-duty foil, thus having a thickness ranging from less than 10 microns to 30 microns or above. The interference material can be provided as a distinct pre-formed sheet that is then installed about the ferritic steel surface. When aluminum foil or mesh is used, it can be applied in a single layer or in multiple layers around the pipe, pipeline or vessel. When a mesh is used, the apertures can be small or large.
[0011] Referring to Fig 3, the interference material 18 can take many forms and can be applied in various ways: as paste 26, powder 28, paint 30, particles 31, distinct layer 32 such as foil or mesh, spray 34 and so on. When the interference material is applied as a fluid or slurry, it can be coated or sprayed, dispersed, injected or diffused onto some or all of the ferritic steel surface that is in contact with the mineral wool and/or on the mineral wool area that will be in contact with the ferritic steel. When the interference material is in solid particular form, it can be mixed and distributed into the mineral wool that will be in contact with the ferritic steel. When the interference material is applied as a distinct layer, it can be wrapped around the ferritic steel before the insulation envelops the pipe, pipeline or vessel. In some scenarios, the interference material can be a metal solid which is vaporized for deposition on the insulation and/or the ferritic steel surface.
In addition, the interference material can be applied evenly about the wool or ferritic steel surface, or it could be applied mainly in certain areas, such as areas that tend to be wetter (e.g., bottom of pipelines).
In addition, the interference material can be applied evenly about the wool or ferritic steel surface, or it could be applied mainly in certain areas, such as areas that tend to be wetter (e.g., bottom of pipelines).
[0012] The interference material, when applied as a distinct layer, can be configured to be malleable to facilitate wrapping around the ferritic steel surface to provide a fitted wrap about the pipe or vessel. The interference material can be in direct contact over the entire outer surface of the pipe or vessel, or there can be regions of direct contact and regions of being spaced apart. The interference material can include a single layer of the material or multiple layers of the same material or different materials. The interference layer can be provided such that it is in direct contact with both the ferritic steel substrate and the surrounding insulation, although it is also possible to have coatings or layers of other materials in between.
[0013] Implementations of the technology can help mitigate Corrosion Under Insulation (CUI) issues in thermal in situ hydrocarbon recovery operations and oil sands extraction Date Recue/Date Received 2024-02-23 operations. Since CUI is another damage mechanism for ferritic steel piping and pipelines, the techniques described herein can further help mitigate such issue. The technology can also increase the safety and efficiency of steel pipes and pipelines as well as pressure vessels; and can also prevent costly repairs and maintenance. The technology can also prolong the lifespan of facilities and equipment.
[0014] The technology that uses an interference material can present advantages over alternative methods, such as the use of expensive spray coatings or providing a polymeric coating over pipes to provide a physical barrier. For example, the interference material can be implemented more economically and efficiently and does not require updating the insulation system as a whole.
[0015] The mineral wool insulation can have various compositions and be from various different suppliers. Mineral wools designed for hot pipe insulation have been found in recent years to cause IGSCC and problems related to the use of such mineral wools could be mitigated using methods described herein.
[0016] The insulated substrate can be part of any application in the oil and gas field or other industries, e.g., refining, upgrading, distribution, chemical plants, food processing plants, and other light and heavy industries, where mineral wool is being used on ferritic materials. Various applications where the insulated substrate is exposed to water, which can leak into the insulation, and/or contains fluid that is under pressure or has elevated temperatures could notably benefit from the electrochemical interference technology described herein. The substrate can be a pipe, fittings, vessels that are exterior and exposed to the elements and could be buried (e.g., buried pipelines). The substrate can be bare and uncoated ferritic steel where the mineral wool has moisture in it from infiltration leading to leachate formation, operating between 70 C and 200 C, and residual stresses in the carbons steel (e.g., from manufacturing, fabrication and/or in service and including induction bends, filter welds on pipe shoes, longitudinal seam welds, girth welds, groove welds of nozzles, etc.). Water ingress through cladding of the substrate forming mineral wool insulation leachates in contact with 70 C to 200 C bare ferritic steel can lead to IGSCC and the interference material can help mitigate such issues.
[0017] Existing substrates can be inspected to assess for the desirability of applying the interference material. For example, substrates can be surveyed for the presence of Date Recue/Date Received 2024-02-23 wet insulation, which may be performed using visual inspection, neutron backscatter, real-time radiography, real-time imaging, or infrared camera techniques. For example, wet insulation can be darker than dry insulation which can be used for identification. If wet insulation is detected, the insulation can be sampled and tested in laboratory, e.g., using CPP, U-bend SCC or other lab screening tests, if desired. Higher risk areas of substrate can receive the application of interference material to mitigate future issues related to IGSCC.
[0018]
Regarding the technology, it is noted that IGSCC initiation in carbon steel under mineral wool is potential dependent and electrochemical interference to prevent crack initiations. Potentiodynamic polarization curves for steel and the zones 1 and 2 where the SCC frequently appears, can be determined (see e.g., Fig 4). As the applied potential of ferritic steels is modified, the ferritic steel corrosion current density changes. There can be typical transition points (see zones 1 and 2 in Fig 4) in the potentiodynamic polarization curve, from where the steel undergoes active corrosion, forms a passive film on the surface, and then the film becomes damaged by dissolution as the potential changes. This cycle of active corrosion, formation of a passive film, and passive film dissolution in these zones is what initiates and grows the crack. Grain boundaries have chemical inhomogeneities and are more active to corrosion than the grains, and therefore are more prone to cracking along the grain boundaries called intergranular Stress Corrosion Cracking. The role of stress is to enhance the breakdown of the passive film at the crack tip. An effect of aluminum or other interference material in the present technology can be to act as a sacrificial anode that corrodes itself in lieu of the steel in an aqueous environment. Steel therefore will not undergo full cycle active corrosion, passive film formation, or film dissolution, so crack initiation and growth is prevented for as long as the interference material in this electrical circuit is not fully consumed.
Regarding the technology, it is noted that IGSCC initiation in carbon steel under mineral wool is potential dependent and electrochemical interference to prevent crack initiations. Potentiodynamic polarization curves for steel and the zones 1 and 2 where the SCC frequently appears, can be determined (see e.g., Fig 4). As the applied potential of ferritic steels is modified, the ferritic steel corrosion current density changes. There can be typical transition points (see zones 1 and 2 in Fig 4) in the potentiodynamic polarization curve, from where the steel undergoes active corrosion, forms a passive film on the surface, and then the film becomes damaged by dissolution as the potential changes. This cycle of active corrosion, formation of a passive film, and passive film dissolution in these zones is what initiates and grows the crack. Grain boundaries have chemical inhomogeneities and are more active to corrosion than the grains, and therefore are more prone to cracking along the grain boundaries called intergranular Stress Corrosion Cracking. The role of stress is to enhance the breakdown of the passive film at the crack tip. An effect of aluminum or other interference material in the present technology can be to act as a sacrificial anode that corrodes itself in lieu of the steel in an aqueous environment. Steel therefore will not undergo full cycle active corrosion, passive film formation, or film dissolution, so crack initiation and growth is prevented for as long as the interference material in this electrical circuit is not fully consumed.
[0019] Several alternative implementations and examples have been described and illustrated herein. The implementations of the technology described above are intended to be exemplary only. A person of ordinary skill in the art would appreciate the features of the individual implementations, and the possible combinations and variations of the components. A person of ordinary skill in the art would further appreciate that any of the implementations could be provided in any combination with the other implementations disclosed herein. It is understood that the technology may be embodied in other specific Date Recue/Date Received 2024-02-23 forms without departing from the central characteristics thereof. The present implementations and examples, therefore, are to be considered in all respects as illustrative and not restrictive, and the technology is not to be limited to the details given herein. Accordingly, while the specific implementations have been illustrated and described, numerous modifications come to mind.
Date Recue/Date Received 2024-02-23
Date Recue/Date Received 2024-02-23
Claims (20)
1. An intergranular stress corrosion cracking (IGSCC)-protected assembly, comprising:
a ferritic steel substrate;
insulation provided about the ferritic steel substrate for thermal insulation thereof;
and an interference material located in between the ferritic steel substrate and the insulation, the interference material being selected to interfere with electrochemical potential of the ferritic steel substrate to inhibit IGSCC when the insulation is exposed to water.
a ferritic steel substrate;
insulation provided about the ferritic steel substrate for thermal insulation thereof;
and an interference material located in between the ferritic steel substrate and the insulation, the interference material being selected to interfere with electrochemical potential of the ferritic steel substrate to inhibit IGSCC when the insulation is exposed to water.
2. The IGSCC-protected assembly of claim 1, wherein the ferritic steel substrate is a pipe.
3. The IGSCC-protected assembly of claim 1, wherein the ferritic steel substrate is a vessel, optionally a pressure vessel.
4. The IGSCC-protected assembly of any one of claims 1 to 3, wherein the insulation is mineral wool.
5. The IGSCC-protected assembly of any one of claims 1 to 4, further comprising an outer cladding.
6. The IGSCC-protected assembly of any one of claims 1 to 5, wherein the interference material comprises aluminum.
7. The IGSCC-protected assembly of any one of claims 1 to 6, wherein the interference material is aluminum.
8. The IGSCC-protected assembly of any one of claims 1 to 8, wherein the interference material is provided as a foil.
9. The IGSCC-protected assembly of any one of claims 1 to 7, wherein the interference material is provided as a mesh.
10. The IGSCC-protected assembly of any one of claims 1 to 7, wherein the interference material is provided as a particulate, such as a powder or particles.
11. The IGSCC-protected assembly of any one of claims 1 to 7, wherein the interference material is provided as a coating that is sprayed or coated onto the substrate and/or the insulation.
12. The IGSCC-protected assembly of any one of claims 1 to 7, wherein the substrate has an uncoated ferritic steel outer surface, the interference material is selected to interfere with the electrochemical potential at temperatures between 70 C and 200 C, the assembly is configured to be located in an exterior environment exposed to water, and the substrate comprises residual stresses in the ferritic steel.
13. The IGSCC-protected assembly of any one of claims 1 to 7, wherein the ferritic steel of the substrate is pipeline grade, piping grade, fitting grade and pressure vessel plate grade ferritic steel.
14. A method for mitigating intergranular stress corrosion cracking (IGSCC) of a ferritic steel substrate surrounded with insulation, comprising providing an interference material in between the ferritic steel substrate and the insulation, the interference material being composed of a material and configured to interfere with electrochemical potential of the ferritic steel substrate to inhibit IGSCC when the insulation is exposed to water.
15. The method of claim 14, wherein the ferritic steel substrate is operated in a thermal in situ hydrocarbon recovery operation at temperatures between 70 C and 200 C.
16. The method of claim 15, wherein the thermal in situ hydrocarbon recovery operation comprises a Steam-Assisted Gravity Drainage (SAGD) process, a solvent-assisted recovery process, a solvent-dominated recovery process, or an in situ combustion process.
17. The method of any one of claims 14 to 16, wherein providing the interference material comprises wrapping a distinct layer of the interference material around the ferritic steel substrate.
18. The method of any one of claims 14 to 16, wherein providing the interference material comprises spraying or coating onto the substrate or the insulation.
19. The method of any one of claims 14 to 18, wherein providing the interference layer comprises retrofitting an existing assembly, comprising:
removing the insulation from the ferritic steel substrate, applying the interference material onto an outer surface of the ferritic steel substrate and/or onto the insulation, and then reinstalling insulation over the substrate.
removing the insulation from the ferritic steel substrate, applying the interference material onto an outer surface of the ferritic steel substrate and/or onto the insulation, and then reinstalling insulation over the substrate.
20. The method of any one of claims 14 to 19, further comprising:
surveying a plurality of substrates to identify substrates that are at-risk for IGSCC, the surveying optionally comprising visual inspection, neutron backscatter, real-time radiography, real-time imaging, or infrared camera techniques and identifying wet insulation;
optionally sampling identified wet insulation to further assess risk of IGSCC, optionally by assessing leachates from the wet insulation;
optionally assessing residual stresses in the substrates to identify elevated residual stress locations that are at-risk for IGSCC; and for at-risk substrates, applying the interference material, optionally at the at-risk locations exposed to wet insulation and/or the elevated residual stress locations.
surveying a plurality of substrates to identify substrates that are at-risk for IGSCC, the surveying optionally comprising visual inspection, neutron backscatter, real-time radiography, real-time imaging, or infrared camera techniques and identifying wet insulation;
optionally sampling identified wet insulation to further assess risk of IGSCC, optionally by assessing leachates from the wet insulation;
optionally assessing residual stresses in the substrates to identify elevated residual stress locations that are at-risk for IGSCC; and for at-risk substrates, applying the interference material, optionally at the at-risk locations exposed to wet insulation and/or the elevated residual stress locations.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA3230133A CA3230133A1 (en) | 2024-02-23 | 2024-02-23 | Use of electrochemical interference material to mitigate stress corrosion cracking of ferritic steel under insulation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA3230133A CA3230133A1 (en) | 2024-02-23 | 2024-02-23 | Use of electrochemical interference material to mitigate stress corrosion cracking of ferritic steel under insulation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA3230133A1 true CA3230133A1 (en) | 2024-04-23 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA3230133A Pending CA3230133A1 (en) | 2024-02-23 | 2024-02-23 | Use of electrochemical interference material to mitigate stress corrosion cracking of ferritic steel under insulation |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA3230133A1 (en) |
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2024
- 2024-02-23 CA CA3230133A patent/CA3230133A1/en active Pending
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