Reducing the risk of high temperature hydrogen attack htha. In this type of corrosion, the scale mentioned above is the chloride of the associated metal. Pdf a systematic study was made of the mechanical properties and the microscopic. 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, high temperature. Micromechanics of high temperature hydrogen attack sabine m.
Htha as the name suggests is the damage to steels exposed to hydrogen at high temperature, while others. Hydrogen as a vehicle fuel can be stored either as a high pressure gas or as a cryogenic liquid section 2. Hightemperature hydrogen attack journal article osti. Detecting and managing high temperature hydrogen attack 20 june 2019 manchester, uk programme. Appendix 8 case study assessing operating limits for c0. Though this updated guidance does provide incremental improvements, it does not address important elements of the csbs recommendation. Journal of materials science 16 1981 29622966 high temperature hydrogen attack of carbon steel d. Detecting and managing high temperature hydrogen attack. 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. 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. Dissolution of hydrogen from the process environment.
This methane does not diffuse out of the metal, and collects in the voids at high pressure and initiates cracks in the steel. Past focus in hydrogen service has been for high temperature, moderately high pressure. At normal atmospheric temperatures, gaseous molecular hydrogen. High temperature hydrogen attack htha inspectioneering. 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 hydrogen atom is the smallest of all atoms and hydrogen attack is similarly insidious and hidden from simple inspection techniques. In addition, the methodology used allows for a differentiation between small inclusions and htha.
Low temperature hydrogen attack on hp separator in h2s service. Accurately predicting htha failures has proven to be one of the most elusive problems challenging the industry for more than half a century. High temperature hydrogen attack is a potentially dangerous damage mechanism that can occur in process equipment that is exposed to hydrogen at elevated temperatures over time and under dry conditions, when hydrogen disassociates into nascent atomic hydrogen and 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 microcracking. Publishers pdf, also known as version of record publication date. Htha can occur either in the parent material, in the weld, or in the heat affected zone itself and manifests itself in several types of alloys. This is not the same as hydrogen embrittlement which degrades toughness at low temperatures. An overview of htha high temperature hydrogen attack of steels operating at. Htha occurs in an environment containing hydrogen and high temperatures, typically in low alloy steels. Hightemperature hydrogen attack of carbon steel springerlink. Cumilox possesses all these inherent characteristics of aluminaandmore.
A quantitative relationship between incubation of attack and temperature and pressure has been obtained. 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. Were pleased to introduce our new patent pending transducer, tula, for htha early stage detection. This is the first of two reports on maintaining the integrity of process plant operating in high temperature hydrogen service. The characteristics that make some of the stainless steels particularly useful in high temperature environments are described, and typical engineering data are. To make detection of htha on stream at 250c, metalscan developed specific probes resisting to high. Nellis this article was submitted to international conference on high pressure science and technology, honolulu, hi, july 2530, 1999 september 9,1999 approved for public release. Ib160 alertpreventing high temperature hydrogen attack. Risk analysis for high temperature hydrogen attack quest integrity. High temperature hydrogen attack is often misinterpreted with hydrogen stress cracking, hydrogen embrittlement, hydrogen induced cracking, hydrogen blistering, stress oriented hydrogen induced cracking etc. 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. The presence of hydrogen in industrial plants is a source of damage. 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. The kinetics of hydrogen attack of a killed steel have been studied in the temperaturerange 800 to 1200 f and in the pressure range 450 to 950 psi hydrogen.
The effects of high pressure, high temperature hydrogen on steel by e. Modeling hydrogen attack effect on creep fracture toughness. The term shall commence on the effective date november 15, 2012 following the completion of existing project and agreement that e2g contractor htha jip shall commence and continue for an initial period of two years unless. Hightemperature hydrogen attack htha testing and analysis. Hightemperature hydrogen attack htha refers to the loss of strength and ductility of steel by hightemperature reaction of absorbed hydrogen with carbides in the steel, resulting in decarburization and internal fissuring. 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. Compounds such as mercaptans and thiophanes that are used to. This paper discusses how joint design and welding defects resulted in the occurrence of htha below the carbon steel nelson curve. Hightemperature hydrogen attack is also referred to as hot hydrogen attack or decarburization. Within the refinery and chemicals industries, high temperature hydrogen attack htha continues to be a processsafety issue. High temperature hydrogen attack gb inspection systems ltd. Steels for hydrogen service at elevated temperatures and. Htha high temperature hydrogen attack is a form of damage commonly observed in steels exposed to high pressure hydrogen at elevated temperatures. Hightemperature hydrogen attack htha corrosionpedia.
Hydrogen can be considered an ideal gas over a wide temperature range and even at high pressures. High temperature hydrogen attack the damage mechanism that leads to htha is. One at ambient temperature is known as hydrogen embrittlement or low temperature hydrogen attack. High temperature hydrogen attack htha application note. This paper introduces phased arrays as an additional technique for the assessment of high temperature hydrogen attack in the base meta. Htha can occur either in the parent material, in the weld, or in the heat affected. High temperature hydrogen attack htha is the progressive degradation of carbon and low alloy steels exposed to hydrogen at elevated temperatures. In a fully implemented system approach, contributions of all of these methods combine instead of focusing on only one or the. Evaluation of mechanical fitness for service of high temperature.
Highlights we study the effect of high temperature hydrogen attack on creep crack growth rates in steels. Aug 14, 2012 the objective of this article is to provide lessons learned from materials, structure, and equipment failures so that costly failures can be prevented through good design, maintenance, and inspection practices, thus increasing safety, equipment reliability, and integrity of designs. Hydrogen damage is a degradation mechanism active in the oil and gas industry. Hydrogen reacts with the carbides in the steel, decarburizing the steel and forming methane. High temperature hydrogen attack htha cracking causes. Jan 20, 2014 high temperature hydrogen attack is a potentially dangerous damage mechanism that can occur in process equipment that is exposed to hydrogen at elevated temperatures over time and under dry conditions, when hydrogen disassociates into nascent atomic hydrogen and is then driven into the steel by the temperature and pressure of the environment. The differential pressure across the membrane creates the hydrogen. High temperatures change the atomic form of hydrogen which makes it permeate. High temperature nuclear reactors for hydrogen production. Tula another ground breaking innovative product from gb inspection systems. Hightemperature sulfidic corrosion of carbon steel by hydrogen sulfide in hydrogenrich streams occurs at temperatures above 230 c. Koiter institute delft delft university of technology, the netherlands email. A hightemperature hydrogen attack htha is the loss of ductility and strength of steel caused by high temperature. Micromechanics of high temperature hydrogen attack.
Preventing high temperature hydrogen attack htha catastrophic htha equipment failure can still occur using the new api nelson curve in february 2016, api published the 8th edition of rp 941. Hightemperature exposure of the carbon and lowalloy steels used for piping and pressure vessels in highpressure hydrogen service leads to a special form of degradation known as htha, sometimes called hydrogen attack. Fissuring and cracking caused by internal methane pressure. Such damage can negatively affect tensile strength and toughness and ultimately cause failure without warning. Control of this hightemperature hydrogen attack is achieved by selection of an appropriate crmo steel with 1. Computational simulations show that fracture toughness is a nonmonotonic function.
Chemical safety and hazard investigation board csb attributed the catastrophic failure to damage caused by hightemperature hydrogen attack htha. The differential pipe had failed due to high temperature hydrogen attack htha. The cell elements are governed by a nonlinear viscous constitutive relation for a voided material. Htha is one such form of degradation which is due to the formation of methane. Hightemperature chlorine corrosion of metals and alloys. The other is a high temperature phenomenon, at the temperature above 200qc, known as high temperature hydrogen attack 2. University of groningen micromechanics of high temperature. Material considerations when working with hydrogen 3. 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. What is high temperature hydrogen attack hthahot hydrogen. 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, high temperature, high purity hydrogen environment.
High temperature hydrogen attack htha is one such form of degradation which is due to the formation of methane ch4 by reaction with carbides in steel. Micromechanics, fracture, creep, hydrogen abstract. This booklet discusses factors that should be considered by engineers facing problems in designing equipment for high temperature service. Onstream inspection for high temperature hydrogen attack. Decarburisation caused by the reaction between carbon as carbide and dissolved hydrogen to form methane. Hydrogen attacks ferritic steels by two distinct and different mechanisms. Htha can occur in carbon steel equipment exposed to hydrogen at temperatures over 400f 205c. Eliezer materials engineering department, ben gurion university of the negev. High temperature hydrogen attack is certainly not an unknown phenomenon in the. This is the second of two reports on maintaining the integrity of process plant operating in high temperature hydrogen service. The data is often fragmented, especially regarding the carbon steel data prior to 1957. 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. Stressaccelerated high temperature hydrogen attack in a. Hightemperature hydrogen attack an overview sciencedirect.
Lavender internationals htha course is endorsed by all major oil companies. Once molecular hydrogen is dissociated, atomic hydrogen diffuses through the dense membrane. Whereas the differential line was supposed to have been closed during the repurposing of the unit in 2008, recent product flow through the line had resulted in hydrogen exposure at temperatures leading to htha damage. Detecting and quantifying high temperature hydrogen attack htha. For many years the sccm task group on high temperature hydrogen attack htha has maintained refining industry data on htha, and developed guidelines to deal with it reference. 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. Outstanding features very high refractoriness, slag and metal corrosion resistance very high stability in oxidizing and reducing atmospheres at high. Preventing high temperature hydrogen attack htha this information bulletin is intended to increase awareness of a potential safety risk identified by the u.
Growth and coalescence of voids along grain boundaries is modeled by a microporous strip of cell elements. Hydrogen damage takes place at two temperature regions, elevated temperatures and temperatures at ambient and. 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. Ductility is the ability to deform permanently prior to fracture, and it is.
Api 941 steels for hydrogen service at elevated temperatures and pressures in petroleum refineries and petrochemical plantssee example below. High temperature corrosion and protection of materials les. 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. High temperature hydrogen attack stress engineering. High temperature hydrogen attack htha is observed in steels. High temperature hydrogen attack htha is a damage mechanism that has the potential to cause catastrophic failure of low alloy steel processing plant. In an attempt to acquire the lowest energy state possible, hydrogen will typically combine with. 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. More recent incidents reported between 2008 and 2015 have resulted in a renewed focus on contributory factors other than temperature and partial pressure of hydrogen in the evaluation of materials in hydrogen service. The stress which a structural material is able to withstand is conditioned by its ductility. High strength low alloy hsla steels, which contain minor additions of alloying elements such as manganese, silicon, chromium and nickel, have a lower oxidation rate. E2g high temperature hydrogen attack joint industry program. Detecting and quantifying high temperature hydrogen attack.
A stream of hydrogen from a leak is almost invisible in daylight. 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. The efficiency improvement of hightemperature electrolysis is best appreciated by assuming that the electricity used comes from a heat engine, and then considering the amount of heat energy necessary to produce one kg hydrogen 141. Oxidation attack is less than about 20 mgcm 2 up to 450 c. Above this temperature, the oxidation rate increases rapidly, following linear kinetics, especially above 600 c. Pdf hightemperature hydrogen attack of carbon steel. High temperature hydrogen attack htha can cause serious damage such as decarburization and microcracking in steels exposed hydrogen at elevated temperatures and high pressure. 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. 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. These micro fissures reduce the strength of the metal and cause cracks to form in. A hydrogen desorption catalyst is located on the low pressure, sweep side of the membrane. At standard temperature and pressure conditions, it is a colourless, odourless, tasteless, nontoxic, noncorrosive, nonmetallic diatomic gas, which is in principle physiologically not dangerous. Htha high temperature hydrogen attack exposed steel. Low and high temperature hydrogen attack detection from ndts.
Htha can have serious consequences and has recently been cited in a number of dangerous failures, including several fatalities. Steels for hydrogen service at elevated temperatures and pressures in petroleum re. 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. 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. This reaction results in hydrogen absorption by the carbides existing in the steel, leading to internal fissures and decarburization.
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