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Content available remote Influence of hydrogen blended gas transmission under transient flow on L485ME steel grade fracture toughness
Uilhoorn Ferdinand, Witek Maciej
Gaz, Woda i Technika Sanitarna
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2023
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Nr 12
2--9
EN
In the present study, the L485ME low-alloy steel grade, widely used in the last few decades in the natural gas transmission pipelines, subjected to hydrogen was investigated with respect to material degradation. A fracture toughness parameter such as the calculated conditional stress intensity factor was compared to the threshold stress intensity factor for the plane strain hydrogen-assisted cracking derived from the experimental data. Based on macroscopic and microscopic evaluation and measurements, the hydrogen-assisted crack size propagation in steel specimens was compared to the subcritical crack growth. The hydrogen content in the tube wall for the base metal and heat-affected zone was estimated, whereas the pressure and temperature conditions in the pipeline were calculated from a non-isothermal transient gas flow model. The results were used to estimate the fracture toughness of the pipe wall material exposed to the hydrogen-blended natural gas.
PL
W niniejszej pracy została przebadana, pod kątem degradacji materiału na skutek działania wodoru, stal niskostopowa gatunku L485ME, szeroko stosowana w ostatnich dziesięcioleciach do budowy rurociągów przesyłowych gazu ziemnego. Parametr odporności na kruche pękanie, taki jak obliczeniowy warunkowy współczynnik intensywności naprężeń, porównano z granicznym współczynnikiem intensywności naprężeń dla wydłużenia płaskiego, który wyznaczono z danych doświadczalnych dla pękania wywołanego wodorem. Na podstawie oceny oraz pomiarów makroskopowych i mikroskopowych, porównano wspomaganą wodorem propagację wielkości podkrytycznego wzrostu pęknięć w próbkach stalowych. Oszacowana została zawartość wodoru w ściance rury dla metalu podstawowego oraz strefy wpływu ciepła. W oparciu o nieizotermiczny model przepływu gazu w stanie nieustalonym, obliczono warunki ciśnienia i temperatury w rurociągu. Uzyskane wyniki wykorzystano do oszacowania odporności na pękanie materiału ścianki rury poddanego działaniu gazu ziemnego z dodatkiem wodoru.
2
Content available An approach to coupling the gas flow dynamics and thermodynamics of hydrogen solubility in L485ME steel grade for estimation of fracture toughness
Witek Maciej, Uilhoorn Ferdinand
Archives of Thermodynamics
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2023
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Vol. 44, no 4
381--403
EN
The paper presents the problem of coupling the gas flow dynamics in pipelines with the thermodynamics of hydrogen solubility in steel for the estimation of the fracture toughness. In particular, the influence of hydrogen blended natural gas transmission on hydrogen solubility and, consequently, on fracture toughness is investigated with a focus on the L485ME low-alloy steel grade. Hydraulic simulations are conducted to obtain the pressure and temperature conditions in the pipeline. The hydrogen content is calculated from Sievert’s law and, as a consequence, the fracture toughness of the base metal and heat-affected zone is estimated. Experimental data is used to define hydrogen-assisted crack size propagation in steel as well as to a plane strain fracture toughness. The simulations are conducted for a real natural gas transmission system and compared against the threshold stress intensity factor. The results showed that the computed fracture toughness for the heat-affected zone significantly decreases for all natural gas and hydrogen blends. The applied methodology allows for identification of the hydrogen-induced embrittlement susceptibility of pipelines constructed from thermomechanically rolled tubes worldwide most commonly used for gas transmission networks in the last few decades.
3
Content available remote Natural gas hydrates in flow assurance
Uilhoorn Ferdinand
Gaz, Woda i Technika Sanitarna
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2022
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Nr 5
7--11
EN
This work focuses on hydrate formation in natural gas pipelines, which is considered as the principal flow assurance problem. A hydrate phase equilibrium model is combined with a transient gas flow model to monitor if, where, and when natural gas in pipelines enters the hydrate formation region. The hydrate model is based on phase equilibria in systems with natural gas containing free and dissolved water. A transient gas flow model is used to describe the flow conditions in natural gas pipelines. This approach enables pipeline operators to monitor the risk of hydrates under normal and emergency conditions, but also to estimate the optimal trade-off between different hydrate prevention techniques. To show the applicability of the method a case study is conducted for a subsea pipeline.
PL
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4
Content available Impact of hydrogen blended natural gas on linepack energy for existing high pressure pipelines
Witek Maciej, Uilhoorn Ferdinand
Archives of Thermodynamics
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2022
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Vol. 43, no 3
111--124
EN
The aim of this work is to examine the impact of the hydrogen blended natural gas on the linepack energy under emergency scenarios of the pipeline operation. Production of hydrogen from renewable energy sources through electrolysis and subsequently injecting it into the natural gas network, gives flexibility in power grid regulation and the energy storage. In this context, knowledge about the hydrogen percentage content, which can safely effect on materials in a long time steel pipeline service during transport of the hydrogen-natural gas mixture, is essential for operators of a transmission network. This paper first reviews the allowable content of hydrogen that can be blended with natural gas in existing pipeline systems, and then investigates the impact on linepack energy with both startup and shutdown of the compressors scenarios. In the latter case, an unsteady gas flow model is used. To avoid spurious oscillations in the solution domain, a flux limiter is applied for the numerical approximation. The GERG-2008 equation of state is used to calculate the physical properties. For the case study, a tree-topological high pressure gas network, which have been inservice for many years, is selected. The outcomes are valuable for pipeline operators to assess the security of supply.
5
Content available A data assimilation approach for estimating strength of steel pipes reinforced with composite sleeves under unsteady pressure-flow conditions
Witek Maciej, Uilhoorn Ferdinand
Archives of Thermodynamics
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2020
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Vol. 41, no 4
3--22
EN
The aim of this paper is twofold: to estimate the unsteady pressure-flow variations in gas transmission pipelines using the ensemblebased data assimilation approach and to analyse the strength of steel tubes reinforced with composite sleeves containing localized part-wall thickness loss caused by corrosion while taking into consideration a safe operating pressure of the pipeline. For a steel thin-walled cylinder containing a partwall metal loss, a flexible wrap of fibreglass as well as carbon glass with epoxy resin are determined. The strength of the repaired pipeline with two kinds of materials for sleeves is investigated taking into consideration the internal pressure at the defect location. For the case study, a section of the Yamal transit pipeline on the Polish territory is selected. The results enable pipeline operators to evaluate the strength of corroded steel pipelines and develop optimal repair activities, which are of vital importance for the maintenance and operation of underground steel networks.
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