The damage occurs as hydrogen atoms diffuse into steels, react with carbon, form methane gas internally in the material, which results in decarburization and fissuring microcracking. Hydrogen exists also as a free element in the atmosphere, but only to the extent of less than 1 ppm by volume. Effect of high temperature hydrogen attack in dissimilar materials. We know hydrogen inside and out the effects of hydrogen can often only be seen by performing testing in high pressures and temperatures. Such damage can negatively affect tensile strength and toughness and ultimately cause failure without warning. Onstream inspection for high temperature hydrogen attack. This is not the same as hydrogen embrittlement which degrades toughness at low temperatures. It occurs in carbon and lowalloyed steels exposed for an extended period to hydrogen under high pressure and at high temperature. High temperature hydrogen attack sentinel integrity. Hydrogen damage takes place at two temperature regions, elevated temperatures and temperatures at ambient and.
Free ionic hydrogen is more reactive than molecular hydrogen, the nonpolarcovalent compound of two hydrogen atoms. Hydrogen attack, detection, assessment and evaluation. The list of acronyms and abbreviations related to htha high temperature hydrogen attack. Htha high temperature hydrogen attack exposed steel. A systematic study was made of the mechanical properties and the microscopic fracture processes associated with hydrogen attack of sae 1020 carbon steel in a wellcontrolled, hightemperature, highpurity hydrogen environment. Paper link free download at researchgate click on text. The failure risk increases as temperatures and hydrogen pressures increase. Petrochemical vessels exposed to high temperature and high pressure hydrogen gas may suffer from high temperature hydrogen attack htha. I expect htha failures to be a small leak or to be discovered during a specofic inspection likely based on htha found at a similar location. High temperature hydrogen attack htha is an insidious condition that can occur in process equipment exposed to hydrogen at elevated temperatures at least 400f or 204c, under dry conditions, when hydrogen disassociates into nascent atomic hydrogen, which is then driven into the steel by the temperature and pressure of the environment. Within the refinery and chemicals industries, high temperature hydrogen attack htha continues to be a processsafety issue. This question is frequently asked by those in ammonia, refinery, and chemical plants, who use piping, heat exchangers, and pressure vessels containing hydrogen at elevated temperatures. Htha high temperature hydrogen attack is a form of damage commonly observed in steels exposed to high pressure hydrogen at elevated temperatures. High temperature hydrogen attack htha is an insidious condition that can occur in process equipment that is exposed to hydrogen at elevated temperatures at least 400f or 204c, under dry conditions, when hydrogen disassociates into nascent atomic hydrogen, which is then driven into the steel by the temperature and pressure of the environment.
The damage occurs as hydrogen atoms diffuse into steels, react with carbon, form methane gas internally in the material, which results in decarburization and fissuring. This selective leaching process is known as hydrogen attack, or high temperature hydrogen attack, and leads to decarburization of the steel and loss of strength and ductility. Free hydrogen ions are produced at the cathode during the formation of iron sulfide scale as well as during the dissolution of this scale. Tula another ground breaking innovative product from gb inspection systems.
View high temperature hydrogen attack research papers on academia. Factors that determine the degree of attack are temperature, hydrogen partial pressure, stress, exposure time, composition of the stee. How is high temperature hydrogen attack corrosion mechanism abbreviated. Stress engineering services ses has observed a growing industry need for htha damage assessments for asset prioritization and capital planning, and has developed two new htha damage life assessment methods. Risk analysis for high temperature hydrogen attack quest integrity. Free hydrogen ions are produced at the cathode during the formation of iron sulfide scale as well. High temperature hydrogen attack is certainly not an unknown phenomenon in the.
The effects of high pressure, high temperature hydrogen on steel by e. The source of hydrogen is the hydrocarbons in the flow steam. Modeling hydrogen attack effect on creep fracture toughness. Api 941 steels for hydrogen service at elevated temperatures and pressures in petroleum refineries and petrochemical plantssee example below this year we will issue a detailed summary of the. The damage is caused by the seepage of hydrogen that reacts with metal. High temperature hydrogen attack htha is a metal degradation phenomenon that is well known to occur in carbon and low steels exposed to high partial pressure of hydrogen at elevated temperature. Risky business inspection options for mitigating high temperature hydrogen attack. Low and high temperature hydrogen attack detection from ndts. High temperature hydrogen attack htha learn more about our latest ondemand webinar.
High temperature hydrogen attack htha is one such form of degradation which is due to the formation of methane ch4 by reaction with carbon in steel. Atomic hydrogen diffuses into the metal and reacts with free carbon and metal carbides to form methane gas. The pipe metallographic crosssections had htha heat. Should hydrogen attack damage be identified, the velocity ratio and spectrum analysis tests can then be used to determine mechanical properties of the hydrogen attack damaged material. High temperature hydrogen attack htha is an intergranular damage mechanism that can occur in process equipment that is exposed to hydrogen at elevated temperatures at least 400 o f or 204 o c, under dry conditions, when hydrogen disassociates into nascent atomic hydrogen, which is then driven into the steel by the temperature and pressure of the environment. Journal of materials science 16 1981 29622966 high temperature hydrogen attack of carbon steel d. In the oil and gas industry, high temperature hydrogen attack htha can occur in steel operating at high temperature, usually above 205c 400f. Pdf a systematic study was made of the mechanical properties and the microscopic fracture processes associated with hydrogen. Hightemperature hydrogen attack an overview sciencedirect. High temperature hydrogen attack htha, also called hot hydrogen attack, is a problem which concerns steels operating at elevated temperatures typically above 400c in hydrogen environments, in refinery, petrochemical and other chemical facilities and, possibly, high pressure steam boilers. Koiter institute delft delft university of technology, the netherlands email. Us6125704a ultrasonic technique for inspection of weld.
An evaluation of high temperature hydrogen attack resistance and a possible new microstructure development based remnant life assessment method of a clean asme gr. Where carbon steel is used as a material of construction in applications involving hydrogen gaseous or liquid, including where it is a constituent part of a fluid, the service conditions should be restricted to limit the effect of high temperature hydrogen attack htha. Inspecting pressure vessels and piping susceptible to high. Hydrogen damage is the generic name given to a large number of metal degradation processes due to interaction with hydrogen hydrogen is present practically everywhere, several kilometres above the earth and inside the earth. The technique is based on comparing the spectral response of the suspect signal with that of a reference signal. The lessons learned relate to the adequacy of design margins.
Such a reaction takes place in the presence of hydrogen sulfide. When steel is exposed to atomic hydrogen at high temperatures and pressures, hydrogen atoms may dissolve into methane, accumulating in bubbles that connect to create microfissures at steel grain boundaries. Avoiding high temperature hydrogen attack hydrogen steel. High temperature hydrogen attack htha in the petrochemical is caused when the hydrogen from the stream seeps into carbon and low alloy steels at high temperatures. Stressaccelerated high temperature hydrogen attack in a catalytic reformer combined feedeffluent exchanger m. Oct 20, 2001 micromechanics of high temperature hydrogen attack micromechanics of high temperature hydrogen attack wriggers, peter. High temperature hydrogen attack htha is a damage mechanism that affects equipment that has been exposed to hydrogen at certain temperatures and pressures. While at operating temp the material had enough toughness to resist a giant crack, but at 70f it was below the brittle transition built long before. Growth and coalescence of voids along grain boundaries is modeled by a microporous strip of cell elements. Ultrasonic techniques for detection of high temperature hydrogen attack. Htha high temperature hydrogen attack mistras group. High temperature hydrogen attack stress engineering. Htha is a hydrogen induced degradation of carbon steels whereby internal hydrogen reacting with carbides forms methane gas bubbles, mainly on grain boundaries gbs, with an associated loss in strength that can result in premature fracture of. Hydrogen reacts with the carbides in the steel, decarburizing the steel and forming methane.
In addition, the methodology used allows for a differentiation between small inclusions and htha. Htha high temperature hydrogen attack all acronyms. At these temperatures, the hydrogen molecules h 2 dissociate into individual hydrogen atoms. The suspect signal is a signal detected in the weld heataffected zone by a high frequency 10 mhz, anglebeam typically 45 degree shear wave transducer operated in the pulseecho mode. This reaction results in hydrogen absorption by the carbides existing in the steel, leading to internal fissures and decarburization. Highlights we study the effect of high temperature hydrogen attack on creep crack growth rates in steels. Micromechanics of high temperature hydrogen attack micromechanics of high temperature hydrogen attack wriggers, peter. Computational simulations show that fracture toughness is a nonmonotonic function. Low temperature hydrogen attack interested in this service. Htha can have serious consequences and has recently been cited in a number of dangerous failures, including several fatalities. High temperature hydrogen attack in hydrogen embrittlement. High temperature hydrogen attack, nde, nondestructive examination, api rp 941, c0. Hydrogen damage is a degradation mechanism active in the oil and gas industry.
Hightemperature hydrogen attack of carbon steel springerlink. A hightemperature hydrogen attack htha is the loss of ductility and strength of steel caused by high temperature. This booklet discusses factors that should be considered by engineers facing problems in designing equipment for high temperature service. High temperature hydrogen attack htha is a phenomenon which occurs within some industrial processes when the presence of hydrogen, subjected to high temperature and pressure, makes plants and systems susceptible to damage. The reference signal is taken from the base metal next to the weld or heataffected zone. Micromechanics of high temperature hydrogen attack sabine m. High temperature hydrogen attack in carbon and low alloy. Engineering materials are exposed to hydrogen and they may interact with it resulting in various kinds of structural damage. If you are interested in this service or require something similar, please complete the enquiry form and we will get in touch with you.
Steels for hydrogen service at elevated temperatures and. High temperature hydrogen attack metal and metallurgy. This can be occurred majorly in fertilizer plants and refineries. C can change the material characteristics negatively. These atoms are small enough that they are able to dissolve into the steel.
Htha stands for high temperature hydrogen attack corrosion mechanism. Us5404754a ultrasonic detection of high temperature. Hightemperature hydrogen attack htha testing and analysis. High temperature hydrogen attack htha, also called hot hydrogen attack, is a problem which affects steels operating at elevated temperatures in hydrogen environments, in refinery, petrochemical and other chemical facilities and, possibly, high pressure steam boilers. Lavender internationals htha course is endorsed by all major oil companies. You may reuse this information not including logos free of charge in. This thesis is brought to you for free and open access by the graduate school at lsu digital commons. Micromechanics, fracture, creep, hydrogen abstract.
Hydrogen attack is one of the major problems in refineries, where hydrogen and hydrocarbon streams are handled up to 20 mpa and approximately 810k level. Inspecting pressure vessels and piping susceptible to high temperature hydrogen attack htha 1 inspecting pressure vessels and piping susceptible to high temperature hydrogen attack htha htha the steel spool operated for more than 20 years in high temperature hydrogen service. Decomposition of these carbides in the presence of dissolved hydrogen at high temperature resulted in the formation of high pressure methane at the grain boundaries. Posts about high temperature hydrogen attack written by milos djukic. High temperature hydrogen attack gb inspection systems ltd. Stressaccelerated high temperature hydrogen attack in a. Jun 08, 2015 high temperature hydrogen attack htha phenomenon high temperature exposure of the carbon and lowalloy steels used for piping and pressure vessels used to contain high pressure hydrogen leads to a special form of degradation known as high temperature hydrogen attack, sometimes called hydrogen attack. Detecting and assessing htha inspection challenges.
The presence of hydrogen in industrial plants is a source of damage. Failure of the transfer line in ammonia plant and remedial. Avoiding high temperature hydrogen attack has equipment deteriorated due to elevated temperature exposure in the presence of hydrogen. Htha high temperature hydrogen attack corrosion mechanism. At g2mt labs, we have been performing high pressure hydrogen analysis for many years on all kinds of steels, metal alloys, composites, powders, and fuel cell materials. Automatic detection of high temperature hydrogen attack. Click here to download a more detailed overview of htha. Risk analysis for high temperature hydrogen attack charles thomas quest integrity group limited lower hutt, new zealand high temperature hydrogen attack htha is a damage mechanism that has the potential to cause catastrophic failure of low alloy steel processing plant. Hightemperature hydrogen attack journal article osti. Micromechanics of high temperature hydrogen attack. Htha is defined as high temperature hydrogen attack corrosion mechanism rarely. This micrograph shows intergranular cracking caused by high temperature hydrogen attack in a c0. When the temperature increases above 400f, molecular hydrogen dissociates to form atomic hydrogen on the surface of the steel. Ngnp concept for largescale centralized nuclear hydrogen production based on high temperature steam electrolysis ngnp htse conceptual design direct coupled to htgr reactor for electrical power and process heat 600 mwth reactor could produce 85 million scfd hydrogen similar to a large.
The kinetics of hydrogen attack of a killed steel have been studied in the temperature range 800 to 1200 f and in the pressure range 450 to 950 psi hydrogen. High temperature hydrogen attack inspection technology. Avoiding high temperature hydrogen attack free download as pdf file. The effect of coking of the tubes would be to reduce heat transfer. The approach is based on backscattering spectrum analysis provided by 0 probe for parent metal and by tofd ut for weld inspection at high temperature. The most catastrophic htha failure i saw occured at ambient temp with n pressure, while on startup. Api refining subcommitte on corrosion and materials contd for many years the sccm task group on high temperature hydrogen attack htha has maintained refining industry data on htha, and developed. Hightemperature hydrogen attack htha corrosionpedia. Pdf effect of high temperature hydrogen attack in dissimilar. A model for high temperature hydrogen attack in carbon.
From a metallurgical pointofview, hightemperature hydrogen attack htha 2, 3 is a incredible example of the mobility and power of tiny hydrogen particles in steel structures. Lifedefect assessment and failures in high temperature power plant, pp. What is high temperature hydrogen attack hthahot hydrogen. Htha hydrogen attack htha high temperature hydrogen attack is a form of damage commonly observed in steels exposed to high pressure hydrogen at elevated temperatures. The characteristics that make some of the stainless steels particularly useful in high temperature environments are described, and typical engineering data are. High temperature hydrogen attack htha is a damage mechanism commonly observed in steels exposed to high temperatures and pressures under a hydrogen rich environment 1. High temperature hydrogen attack htha modeling prediction. The initial studies suggest that this is due to free carbon being present in the. Pdf hightemperature hydrogen attack of carbon steel. Coking would be more likely at the highest temperatures i. Hydrogen reacts with the carbides in the steel, decarburizing the steel and forming methane gas bubbles at the grain boundaries with no loss of thickness. As atomic hydrogen diffuses into steels, it promotes internal decarburization by combining with carbon and forming methane fig.
High temperature hydrogen attack htha can cause serious damage such as decarburization and microcracking in steels exposed hydrogen at elevated temperatures and high pressure. A microstructurebased mechanism of cracking in high. Htha affects carbon and low alloy steels, but is most commonly. High temperature exposure of the carbon and lowalloy steels used for piping and pressure vessels in high pressure hydrogen service leads to a special form of degradation known as htha, sometimes called hydrogen attack. High temperature hydrogen attack is also referred to as hot hydrogen attack or decarburization. High temperature hydrogen attack htha inspectioneering. High temperature hydrogen attack htha of steels plagues higher temperature industrial applications, especially in the petrochemical industry, due to the lack of a mechanistic understanding of the phenomenon and the use of empirically established design criteria, such as the nelson curves. Risky business inspection options for mitigating high. The hydrogen atom is the smallest of all atoms and hydrogen attack is similarly insidious and hidden from simple inspection techniques. This methane does not diffuse out of the metal, and collects in the voids at high pressure and initiates cracks in the steel. The cell elements are governed by a nonlinear viscous constitutive relation for a voided material.
Evaluation of mechanical fitness for service of high temperature. The cause of this behaviour is a degradation phenomenon called hydrogen attack, or hightemperature hydrogen attack htha which produces an irreversible damage and arises from the nucleation, growth and coalescence of methane bubbles to form fissures, mainly along the grain boundaries. High partial hydrogen pressure higher than 30 bar and high temperature higher than 300. The fundamentals of high temperature hydrogen attack htha. Pdf dissimilar materials are welded in many industrial and manufacturing applications. Where deterioration is attributed to wet hydrogen sulfide, hydrogen attack of high temperature, the suitability of degraded materials for continuing service must be closely monitored and or life prediction tools enhanced. Chris jones quest integrity, charles thomas quest integrity, and david keen incitec pivot limited as seen in the september october issue of world fertilizer magazine. Api rp 571 high temperature hydrogen attack duration. Htha can occur either in the parent material or in the weld itself and manifests itself in several types of alloys. Htha high temperature hydrogen attack is a form of degradation due to the formation of methane ch4 by reaction with carbon in steel. Eliezer materials engineering department, ben gurion university of the negev.
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