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. A quantitative relationship between incubation of attack and temperature and pressure has been obtained. Note that this is not the same as hydrogen embrittlement which degrades toughness at low temperatures. Pdf effect of high temperature hydrogen attack in dissimilar. Nondestructive evaluation of piping samples for high. Ib160 alertpreventing high temperature hydrogen attack. Rp 941 to predict susceptibility of equipment to htha damage. High temperature sulfidic corrosion of carbon steel by hydrogen sulfide in. Maintaining the integrity of process plant susceptible to high temperature hydrogen attack. At high temperature, and particularly in the presence of catalyst, hydrogen gas molecules can dissociate.
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. Risk analysis for high temperature hydrogen attack quest integrity. The present use of manufactured hydrogen is primarily for the production of. In addition, the methodology used allows for a differentiation between small inclusions and htha. The fundamentals of high temperature hydrogen attack htha. 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 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 resulting hydrogen atoms can diffuse into the steel, and react with carbon from. High temperatures change the atomic form of hydrogen which makes it permeate. 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. Hightemperature hydrogen attack an overview sciencedirect.
This is not the same as hydrogen embrittlement which degrades toughness at low temperatures. High temperature hydrogen attack htha application note. An overview of htha high temperature hydrogen attack of steels operating at elevated temperatures is given in this faq. Api 941 steels for hydrogen service at elevated temperatures and pressures in petroleum refineries and petrochemical plantssee example below.
Detection and assessment of high temperature hydrogen. Dissolution of hydrogen from the process environment. Detecting and quantifying high temperature hydrogen attack. Hydrogen reacts with the carbides in the steel, decarburizing the steel and forming methane. This is a type of deterioration which can be linked to corrosion and corrosioncontrol processes. 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.
The differential pipe had failed due to high temperature hydrogen attack htha. 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 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. 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. The ait is the minimum temperature required to initiate selfsustained combustion. Pdf dissimilar materials are welded in many industrial and manufacturing applications. Reducing the risk of high temperature hydrogen attack. Carbon steel process plant that operates with hydrogen at elevated pressure and temperature can be weakened by a phenomenon known as high temperature hydrogen attack htha. Pdf a systematic study was made of the mechanical properties and the microscopic fracture processes associated with hydrogen attack of. Risk reduction projects combating high temperature. Pdf hightemperature hydrogen attack of carbon steel.
A hightemperature hydrogen attack htha is the loss of ductility and strength of steel caused by high temperature. Outstanding features very high refractoriness, slag and metal corrosion resistance very high stability in oxidizing and reducing atmospheres at high. The presence of hydrogen in industrial plants is a source of damage. 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. Steels for hydrogen service at elevated temperatures and. Eliezer materials engineering department, ben gurion university of the negev.
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. Hightemperature sulfidic corrosion of carbon steel by hydrogen sulfide in hydrogenrich streams occurs at temperatures above 230 c. Micromechanics, fracture, creep, hydrogen abstract. Though this updated guidance does provide incremental improvements, it does not address important elements of the csbs recommendation. Onstream inspection for high temperature hydrogen attack.
Such damage can negatively affect tensile strength and toughness and ultimately cause failure without warning. High temperature hydrogen attack htha inspectioneering. Control of this high temperature hydrogen attack is achieved by selection of an appropriate crmo steel with 1. Hydrogen is an important raw material for the chemical and the refinery industry, and it may play a future role in the energy sector. 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.
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. The relatively high autoignition temperature makes ignition of a hydrogen air mixture unlikely from heat alone without an additional ignition source. 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. Stressaccelerated high temperature hydrogen attack in a. 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. 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. Appendix 8 case study assessing operating limits for c0. At standard temperature and pressure conditions, it is a colourless, odourless, tasteless, nontoxic, noncorrosive, nonmetallic diatomic gas, which is in principle physiologically not dangerous. What is high temperature hydrogen attack hthahot hydrogen. 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. We are pleased to introduce tula novel transducer design versatile application usable on all advanced ut instruments sensitive to extremely small flaws.
Safe operation of a high temperature hydrogen attack. High temperature electrolysis for efficient hydrogen. 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. Detecting and quantifying high temperature hydrogen attack htha norbert trimborn 8 mistras group bv 2, spijkenisse, nepal. Control of this hightemperature hydrogen attack is achieved by selection of an appropriate crmo steel with 1. This form of hydrogen damage is called high temperature hydrogen attack htha, and this recommended practice discusses the resistance of steels to htha. 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. 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. Nickelcontaining alloys in hydrofluric acid, hydrogen fluoride, and flu orine created date. High temperature hydrogen attack htha is a damage mechanism that has the potential to cause catastrophic failure of low alloy steel processing plant.
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. 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. This is the second of two reports on maintaining the integrity of process plant operating in high temperature hydrogen service. Moving the bounds of ndt gb inspection systems ltd.
This reaction results in hydrogen absorption by the carbides existing in the steel, leading to internal fissures and decarburization. High temperature exposure of the carbon and lowalloy steels used for piping and pressure vessels fig. The effects of high pressure, high temperature hydrogen on steel by e. 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. Hydrogen can be considered an ideal gas over a wide temperature range and even at high pressures.
Micromechanics of high temperature hydrogen attack sabine m. Journal of materials science 16 1981 29622966 hightemperature hydrogen attack of carbon steel d. Risk reduction projects combating high temperature hydrogen attack. 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. Hightemperature hydrogen attack htha corrosionpedia. Joint industry program proposal high temperature hydrogen. 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.
Tesoro heat exchanger in the safe operating region. Atomic hydrogen formed in corrosion processes or by dissociation of molecular hydrogen in a gas stream at the steel surface diffuses into steel. Htha can result in sudden, catastrophic failures that are costly and dangerous. Visit the rr14 report pdf portable document format hse. Preventing high temperature hydrogen attack htha discussion. Decarburisation caused by the reaction between carbon as carbide and dissolved hydrogen to form methane. Cumilox possesses all these inherent characteristics of aluminaandmore. High temperature hydrogen attack htha is a potential damage mechanism for steels operating in pressurized hydrogen environments at elevated temperatures. High temperature hydrogen attack htha cracking causes. High temperature hydrogen attack the damage mechanism that leads to htha is. This is the first of two reports on maintaining the integrity of process plant operating in high temperature hydrogen service. High temperature hydrogen attack htha can cause serious damage such as decarburization and microcracking in steels exposed hydrogen at elevated temperatures and high pressure. These technologies include an evaluation and development of inspection methods for detection and sizing, fitnessforservice assessment procedures, and riskbased inspection approaches.
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