The effects of high pressure, high temperature hydrogen on steel by e. 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. This form of hydrogen damage is called high temperature hydrogen attack htha, and this recommended practice discusses the resistance of steels to htha. Pdf dissimilar materials are welded in many industrial and manufacturing applications. The inl high temperature electrolysis project history and background inl served as the lead laboratory for high temperature electrolysis hte research and development from 2003 2009, under the doe nuclear hydrogen initiative nhi during fy09, hte was selected by doe as the primary nuclear hydrogen. This is not the same as hydrogen embrittlement which degrades toughness at low temperatures. Detecting and quantifying high temperature hydrogen attack htha norbert trimborn 8 mistras group bv 2, spijkenisse, nepal.
We are pleased to introduce tula novel transducer design versatile application usable on all advanced ut instruments sensitive to extremely small flaws. The ait is the minimum temperature required to initiate selfsustained combustion. 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. 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. 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 differential pipe had failed due to high temperature hydrogen attack htha. At grain boundaries, crystal imperfections, inclusions, discontinuities and other defects, the atomic hydrogen reacts with the dissolved carbon or with the metal carbides, forming methane. Hydrogen can be considered an ideal gas over a wide temperature range and even at high pressures. Nondestructive evaluation of piping samples for high. High temperature hydrogen attack htha is a damage mechanism that has the potential to cause catastrophic failure of low alloy steel processing plant. Preventing high temperature hydrogen attack htha discussion. This is the first of two reports on maintaining the integrity of process plant operating in high temperature hydrogen service. This booklet discusses factors that should be considered by engineers facing problems in designing equipment for high temperature service.
Preventing high temperature hydrogen attack htha this information bulletin is intended to increase awareness of a potential safety risk identified by the u. Ib160 alertpreventing high temperature hydrogen attack. High temperature hydrogen attack the damage mechanism that leads to htha is. Cumilox possesses all these inherent characteristics of aluminaandmore. This is the second of two reports on maintaining the integrity of process plant operating in high temperature hydrogen service. A hightemperature hydrogen attack htha is the loss of ductility and strength of steel caused by high temperature. Moving the bounds of ndt gb inspection systems ltd. The presence of hydrogen in industrial plants is a source of damage.
Nickelcontaining alloys in hydrofluric acid, hydrogen fluoride, and flu orine created date. Htha occurs in an environment containing hydrogen and high temperatures, typically in low alloy steels. Rr13 maintaining the integrity of process plant susceptible to high temperature hydrogen attack. The data is often fragmented, especially regarding the carbon steel data prior to 1957. Reducing the risk of high temperature hydrogen attack. Pdf effect of high temperature hydrogen attack in dissimilar. 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. Htha is one such form of degradation which is due to the formation of methane ch4 by reaction with carbon in steel. The rupture of the e heat exchanger was the result of the carbon steel exchanger being severely weakened by a damage mechanism known as htha. Outstanding features very high refractoriness, slag and metal corrosion resistance very high stability in oxidizing and reducing atmospheres at high. This paper discusses how joint design and welding defects resulted in the occurrence of htha below the carbon steel nelson curve. High temperature electrolysis for efficient hydrogen. 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.
Atomic hydrogen formed in corrosion processes or by dissociation of molecular hydrogen in a gas stream at the steel surface diffuses into steel. Decarburisation caused by the reaction between carbon as carbide and dissolved hydrogen to form methane. Rp 941 to predict susceptibility of equipment to htha damage. High temperature hydrogen attack htha inspectioneering. This reaction results in hydrogen absorption by the carbides existing in the steel, leading to internal fissures and decarburization. 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. These technologies include an evaluation and development of inspection methods for detection and sizing, fitnessforservice assessment procedures, and riskbased inspection approaches. High temperature hydrogen attack htha is a potential damage mechanism for steels operating in pressurized hydrogen environments at elevated temperatures. The fundamentals of high temperature hydrogen attack htha.
At standard temperature and pressure conditions, it is a colourless, odourless, tasteless, nontoxic, noncorrosive, nonmetallic diatomic gas, which is in principle physiologically not dangerous. The characteristics that make some of the stainless steels particularly useful in high temperature environments are described, and typical engineering data are. Fissuring and cracking caused by internal methane pressure. It involves the ingress of hydrogen into a component, an event that can seriously reduce the ductility and loadbearing capacity, cause cracking and catastrophic brittle failures at stresses below the yield stress of susceptible materials. Htha can result in sudden, catastrophic failures that are costly and dangerous. In addition, the methodology used allows for a differentiation between small inclusions and htha. Control of this hightemperature hydrogen attack is achieved by selection of an appropriate crmo steel with 1. Micromechanics, fracture, creep, hydrogen abstract. These micro fissures reduce the strength of the metal and cause cracks to form in. A quantitative relationship between incubation of attack and temperature and pressure has been obtained. Hightemperature hydrogen attack htha corrosionpedia. What is high temperature hydrogen attack hthahot hydrogen.
High temperature hydrogen attack htha cracking causes. 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 relatively high autoignition temperature makes ignition of a hydrogen air mixture unlikely from heat alone without an additional ignition source. Risk analysis for high temperature hydrogen attack quest integrity. 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. 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. Tesoro heat exchanger in the safe operating region. Control of this high temperature hydrogen attack is achieved by selection of an appropriate crmo steel with 1.
High temperature exposure of the carbon and lowalloy steels used for piping and pressure vessels fig. Eliezer materials engineering department, ben gurion university of the negev. Dissolution of hydrogen from the process environment. High temperatures change the atomic form of hydrogen which makes it permeate. Appendix 8 case study assessing operating limits for c0. Api 941 steels for hydrogen service at elevated temperatures and pressures in petroleum refineries and petrochemical plantssee example below. Onstream inspection for high temperature hydrogen attack. Detecting and quantifying high temperature hydrogen attack. Though this updated guidance does provide incremental improvements, it does not address important elements of the csbs recommendation.
Pdf hightemperature hydrogen attack of carbon steel. 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. At high temperature, and particularly in the presence of catalyst, hydrogen gas molecules can dissociate. Hightemperature sulfidic corrosion of carbon steel by hydrogen sulfide in hydrogenrich streams occurs at temperatures above 230 c. Maintaining the integrity of process plant susceptible to high temperature hydrogen attack. Hydrogen reacts with the carbides in the steel, decarburizing the steel and forming methane. Visit the rr14 report pdf portable document format hse. 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. This is a type of deterioration which can be linked to corrosion and corrosioncontrol processes.
Risk reduction projects combating high temperature hydrogen attack. High temperature hydrogen attack htha application note. Pdf a systematic study was made of the mechanical properties and the microscopic fracture processes associated with hydrogen attack of. 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 sulfidic corrosion of carbon steel by hydrogen sulfide in. Such damage can negatively affect tensile strength and toughness and ultimately cause failure without warning. Micromechanics of high temperature hydrogen attack sabine m. An overview of htha high temperature hydrogen attack of steels operating at elevated temperatures is given in this faq. 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. 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. Note that this is not the same as hydrogen embrittlement which degrades toughness at low temperatures. No part of this document or the related files may be reproduced or transmitted in any form, by any means, electronic, photocopying, recording, or otherwise to individuals outside the company without the prior written permission.
Journal of materials science 16 1981 29622966 hightemperature hydrogen attack of carbon steel d. Joint industry program proposal high temperature hydrogen. High temperature hydrogen attack htha is a problem that has been affecting energy related systems such as coal gasifiers and fuel processors for a long time. 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. 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. Hydrogen is an important raw material for the chemical and the refinery industry, and it may play a future role in the energy sector. The present use of manufactured hydrogen is primarily for the production of. 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. 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.
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