The hydrogen is first produced as hydrogen atoms h which normally combine rapidly to form hydrogen molecules h 2. Hydrogen induced cracking hic assessment in a gas processing plant case study mohammed a abufour, mohammad. Broken up into two logical parts, the book begins with coverage on pipelines, including essential topics, such as. The high initial capital costs of new pipeline construction constitute a major barrier to. Hydrogen atoms are very reactive and combine with almost all elements. Stresscorrosion cracking, materials performance and. Hydrogen blistering occurs when hydrogen atoms diffuse into the steel, and hydrogen gas nucleates at internal defects and inclusions, forming voids which eventually generate enough pressure to locally rupture the metal. Hydrogen embrittlement, another form of eac, refers to one of three forms of hydrogen degradation to the proper ties of a metal hydrogenstress cracking.
Hydrogen induced cracking of x80 pipeline steel request pdf. Worldwide, air products pipeline operational expertise is evidenced by nearly 40 years of safe operation of its network of systems. Oil and gas pipelines and piping systems 1st edition. Gaseous hydrogen can be transported through pipelines much the way natural gas is today.
Pipeline steels are extremely and dangerously susceptible to fatigue failure in the presence of hydrogen illinois mechanismbased. Transporting gaseous hydrogen via existing pipelines is a lowcost option for delivering large volumes of hydrogen. Sem observations illustrated that all hic cracks were formed at the center of cross section in the x60 steel. Explains why pipeline stress corrosion cracking happens and how it can be prevented. Hydrogen induced cracking hic occurs when carbon steel is exposed to hydrogen sulphide h 2 s and is the direct result of electrochemical corrosion reactions between the sour service or wet h 2 s environment. Scc has been observed inside storage tanks and user terminals that contain fuelgrade ethanol. Hydrogeninduced cracking hic refers to the internal cracks brought about by material trapped in budding hydrogen atoms. Hydrogen embrittlement of pipelines and remediation mixing with water vapor.
Atomic hydrogen, and not the molecule, is the smallest atom and it is small enough to diffuse readily through a metallic structure. It is a complex process that is not completely understood because of the variety and complexity of mechanisms that can lead to embrittlement. There are no criteria codes and standards with predictive capabilities. 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. Furthermore, as hydrogen pipeline networks expand, many of the same construction and operating features of natural gas networks would be replicated. There are several types of tests to determine exact type of corrosion resistance property of any material. Hydrogeninduced cracking is also known as cold cracking, delayed cracking or underbead cracking. In such cases the cathodic reaction aggravates the cracking. Inversely proportioned to increasing temperature above room temperature 25 degrees c. The factors that affect hydrogen induced cracking are discussed in table 2.
Hydrogen embrittlement also known as hydrogen assisted cracking and hydrogeninduced cracking, describes the embrittling of metal after being exposed to hydrogen. Hydrogen induced cracking sievert group of companies. Hydrogen pipelines in service operate in the absolute absenceof any design criteria against hydrogeninduced failure. Hic testing apparatus is provided with specially made rack to keep the samples with minimum surface contact and all the specimens can be viewed during the test period easily. Hydrogeninduced damage in sour, wet crude pipelines.
In some cases the damage has taken the form of blistering preexisting mill laminations in the pipe. The gti assessment therefore details the implications of hydrogen blending in relation to the distinct characteristics of the u. The effect of inclusions in the steel on the crack initiation was analyzed. As a form of hydrogen stress cracking, ssc is a cracking mechanism in pipelines, facilities piping and any equipment that comes in contact with sour wet h2s service conditions. Hydrogen induced cracking steel features, applications. Dilbit and synbit corrosivity and existing pipelines 29 6. Published by welding technology institute of australia wtia, silverwater, nsw, australia, 1999. Hydrogen piping and pipelines, yongyi wang h2 service. Hydrogen induced cracking tests were conducted on high strength steels and nickeliron base alloys using the constant displacement boltloaded compact specimen. Rosen 15 types of pipeline cracks inspection solutions.
When they are in good working order, they deliver fuel to meet the evergrowing demand for energy around the world. Assessment of hydrogen compatibility of the existing natural gas pipeline system for transporting hydrogen suitable steels, andor coatings, or other materials to provide safe and reliable hydrogen transport and reduced capital cost 2. In this work, the hydrogeninduced cracking hic behavior of x100 pipeline steel was investigated by a combination of tensile test, electrochemical hydrogen permeation measurement and surface characterization techniques. Hydrogeninduced cracking assessment in pipeline steels. Approximately 1,600 miles of hydrogen pipelines are currently operating in the united states.
Hydrogeninduced cracking hic and blistering have been documented in eight sour crude oil pipelines with water cuts wcs known or believed to be less than 1 vol %. The molecular form of hydrogen cannot diffuse and is stable. Hughes 1880 note on some effects produced by the immersion of steel and iron wires in acidulated water. Effects of hydrogencharging on the susceptibility of x100. Johnson 1875 on some remarkable changes produced in iron and steels by the action of hydrogen acids. Corrosionpedia what is hydrogeninduced cracking hic. The results obtained contribute to better understanding of hydrogeninduced cracking hic. The hydrogeninduced cracking hic behavior of x80 pipeline steel was studied by means of electrochemical charging, hydrogen permeation tests, tension test.
Design, construction, management, and inspection delivers all the critical aspects needed for oil and gas piping and pipeline condition monitoring and maintenance, along with tactics to minimize costly disruptions within operations. Weld metal hydrogen cracking in pipeline girth welds, proc. Hydrogen cracking its causes, costs and future occurrence. Hydrogen induced cracking hic is a common form of wet h2s cracking caused by the blistering of a metal due to a high concentration of hydrogen. Blending hydrogen into natural gas pipeline networks. The paper looks at the problem of hydrogen cracking both in general fabrication and with particular reference to. Many of the features of hydrogen pipelines are similar to those of natural gas pipelines. Liquid hydrogen and slush hydrogen exist only at very low temperatures, and with an extremely small latent heat of evaporation, they evaporate easily. When atomic hydrogen is trapped at irregularities within the pipe steel e. Hydrogen induced cracking hic there are several categories of hydrogen phenomena that are localized in nature. Hic usually occurs due to the effects of aqueous hydrogen charging of steel in wet h2s refinery process environments. Particularly common to the oil and gas industry where the use of steel. Hic hydrogeninduced cracking hisc hydrogeninduced stress cracking hml high medium low risk notation.
Hydrogen cracking during fabrication of steel structures, including pipelines, has caused considerable costs to industry in the past including occasionally loss of life. Hydrogen embrittlement he also known as hydrogen assisted cracking hac and hydrogeninduced cracking hic, describes the embrittling of metal after being exposed to hydrogen. The transportation of liquid or slush hydrogen, therefore, poses many problems at the present technological. Pipelines offer a safe, robust and reliable supply of hydrogen to the refinery and petrochemical industry. An effective finite element model for the prediction of. The boltloaded specimen was subjected to both acid and electrochemical cell environments in order to produce hydrogen. Atomic hydrogen diffuses inside the metal and causes localized deformation, or even destroys the walls of the vessel. At intermediate stage adsorbed hydrogen atoms hads are present. State of the art report dilbit corrosivity 12671rpt001 rev 1 contents page ii 5. Hydrogen induced cracking hic is a mechanical fracture caused by the penetration and diffusion of atomic hydrogen into the internal structure of steel, which changes into molecular hydrogen in the internal interface between nonmetallic inclusion and base material. For that reason, information on hydrogen pipelines is the focus of this document. Hydrogeninduced cracking an overview sciencedirect topics. Electrochemical hydrogen charging and permeation techniques were used to characterize hydrogen distribution, trapping, and diffusion in x60 and x60 sour service x60ss pipeline steels.
That means the hydroxyle ions decharge separately one by one. Hydrogen induced cracking hydrogen induced cracking hic when corrosion of steel occurs in an acid solution e. It involves atomic hydrogen, which is the smallest atom, that diffuses into a metallic structure. Hydrogen delayed cracking of highstrength weldable steels 7 these reactions take place in two steps.
The latter is hydrogen gas that escapes to the immediate environment. Mechanisms that have been proposed to explain embrittlement include the formation of brittle hydrides, the creation of voids that can lead to bubbles and pressure buildup within a material and e. Evaluation of pipeline and pressure vessel steels for. Unfortunately, the term hydrogeninduced cracking, usually abbreviated as hic, has been introduced to designate cracking sometimes encountered in pipelines or vessels as a result of hydrogen picked up in service. It is a dangerous type of corrosion which produces some of the toughest technical. Worlds largest hydrogen pipeline supply network adds. The blistering damage tends to form parallel to the surface and to the direction of hoop stress.
The model is able to mimic the pressure buildup mechanism related to the recombination of atomic hydrogen into hydrogen gas within the crack cavity. Hydrogen gas, liquid hydrogen, and slush hydrogen can be transported by pipeline. Hic test, hydrogen induced cracking test, step wise. Hydrogen induced cracking tests of high strength steels. When the crystal lattice is in contact or is saturated with atomic hydrogen, the mechanical. One adverse effect observed in pipeline and pressure vessel steels is the development of cracks along the rolling. Hydrogen blistering a special case of hydrogen damage is known as hydrogen blistering. Material selection for sour service environment pipeline.
Pdf the consequences of cracks formed on the oil and gas. Hydrogen induced cracking of pipeline and pressure vessel. This paper presents a comprehensive finite element model for the numerical simulation of hydrogen induced cracking hic in steel pipelines exposed to sulphurous compounds, such as hydrogen sulphide h 2 s. In the case of a crystal lattice becoming saturated or coming into contact with atomic hydrogen, many alloys and metals may. Gulf coast hydrogen pipeline system, air products also operates pipelines in. Some of the examples are resistance to hydrogen sulphide h2s cracking such as sulphide stress cracking ssc, stress oriented hydrogen induced cracking sohic, hydrogen induced cracking hic, step wise cracking swc, soft zone cracking szc etc. Cres performs full integrity assessment of resulting weld joints under static and cyclic fatigue loads.
The consequences of cracks formed on the oil and gas pipelines weld joints. Nontoxic 14 times lighter than air rapidly dissipates h2 flame emits 10% of the radiant heat of a hydrocarbon fire no smoke or emissions requires a constrained volume to explode h2air mixture must be twice as rich as natural gas to explode explosive power is 22 times less than gasoline vapor. From a welding point of view, the challenge of higher strength pipe is there is more possibility of hydrogeninduced cracking, which means traditional welding methods cant be used, macgillivray says. The analysis results may be used to assess the propensity of hydrogen induced cracking andor haz softening in modern microalloyed steels. This is a type of deterioration which can be linked to corrosion and corrosioncontrol processes. Hydrogen induced cracking test instrument is supplied with standard size of 12l x 12w x 9h. Hydrogen which is produced at cathode due to corrosion reaction, diffuses into the steel and result in cracking in wet hydrogen sulfide environment. The presence of hydrogen in material is a potential source of defects and must be detected before it reaches a. Absorption of hydrogen generated by corrosion of steel in a wet hydrogen sulfide h 2 s environment can have several effects that depend on the properties of the steel, manufacturing or forming processes, the characteristics of the environment, and other variables. Hydrogen gas introduced thinning thinning main crack main crack microcrack formed crack linkage. Hydrogen embrittlement and stress corrosion cracking. Hydrogen induced cracking hic in the oil and gas industry.
1342 1226 944 1034 137 1079 1151 33 225 996 36 1096 1097 823 1267 711 90 944 630 968 292 123 631 1148 109 102 1475 457 446 885 1264 540 1319 1265 1178 933 1061