United Kingdom
CFD Dispersion Simulations of Compressed Hydrogen Releases through TPRD Inside Scaled Tunnel
Sep 2023
Publication
To achieve the net zero carbon emissions goals by 2050 the transition to cleaner forms and carriers of energy should be accelerated without though jeopardizing the public safety. Although hydrogen has been deemed to play significant role in the energy transition for years now there are still concerns for its risks that hamper its widespread implementation in several applications like for instance automobile applications. Hydrogen-powered vehicles raise concerns about their safety especially inside confined spaces like tunnels and thus research on that topic has been intensified during the last years. In this context experiments have been conducted by UK HSE within the EU-funded project HyTunnel-CS to examine hydrogen dispersion and deflagration inside a scaled tunnel resulting from fuel cell car bus and train release.<br/>In this work that was also carried out within the HyTunnel-CS we present the Computational Fluid Dynamics (CFD) simulations of the HSE unignited experiments. Blowdown tests related to high-pressure hydrogen releases through Thermal Pressure Relief Device (TPRD) installed in car and in train were modeled using the ADREA-HF code. The scope of these simulations was two-fold: a) contribute to the design of the experiments (e.g. indicate sensor positioning ignition point etc.) and the interpretation of hydrogen behavior and b) validate the CFD code. For the former pre-test simulations preceded the experiments to provide design recommendations. When the experiments were conducted the measurements were used for the code validation. Overall the CFD results are in satisfactory agreement with the experiments. Finally simulations with different ventilation rates and with model vehicles inside the tunnel were conducted to examine their effect on mixture dispersion and tunnel safety.
CFD Analysis of Delayed Ignition Hydrogen Releases from a Train Inside a Tunnel
Sep 2023
Publication
In the present work we present the results of numerical simulations involving the dispersion and combustion of a hydrogen cloud released in an empty tunnel. The simulations were conducted with the use of ADREA-HF CFD code and the results are compared with measurements from experiments conducted by HSE in a tunnel with the exact same geometry. The length of the tunnel is equal to 70 m and the maximum height from the floor is equal to 3.25 m. Hydrogen release is considered to occur from a train containing pressurized hydrogen stored at 580 bars. The release diameter is equal to 4.7 mm and the release direction is upwards. Initially dispersion simulation was performed in order to define the initial conditions for the deflagration simulations. The effect of the initial wind speed and the effect of the ignition delay time were investigated. An extensive grid sensitivity study was conducted in order to achieve grid independent results. The CFD model takes into account the flame instabilities that are developed as the flame propagates inside the tunnel and turbulence that exists in front of the flame front. Pressure predictions are compared against experimental measurements revealing a very good performance of the CFD model.
The Regulatory Framework of Geological Storage of Hydrogen in Salt Caverns
Sep 2023
Publication
A growing share of renewable energy production in the energy supply systems is key to reaching the European political goal of zero CO2 emission in 2050 highlighted in the green deal. Linked to the irregular production of solar and wind energies which have the highest potential for development in Europe massive energy storage solutions are needed as energy buffers. The European project HyPSTER [1] (Hydrogen Pilot STorage for large Ecosystem Replication) granted by the Clean Hydrogen Partnership addresses this topic by demonstrating a cyclic test in an experimental salt cavern filled with hydrogen up to 3 tons using hydrogen that is produced onsite by a 1 MW electrolyser. One specific objective of the project is the assessment of the risks and environmental impacts of cyclic hydrogen storage in salt caverns and providing guidelines for safety regulations and standards. This paper highlights the first outcome of the task WP5.5 of the HyPSTER project addressing the regulatory and normative frameworks for the safety of hydrogen storage in salt caverns from some selected European Countries which is dedicated to defining recommendations for promoting the safe development of this industry within Europe.
Nuclear Enabled Hydrogen CO-generation: Safety and Regulatory Insight
Sep 2023
Publication
National Nuclear Laboratory (NNL) is aiming to demonstrate through a research and development programme that nuclear enabled hydrogen can be used to support future clean energy systems. Demonstrating the safe operation of hydrogen facilities co-generating with a nuclear reactor will be key to enabling the deployment and success of nuclear enabled hydrogen technologies in the future. During the deployment continuity of supply will be paramount and possibly requires inter-seasonal storage. Co-generation is a means of using a source of energy in this case a nuclear reactor to efficiently produce power and thermal energy. Since a great deal of the heat energy is lost to the environment in a power plant making use of wasted energy for other useful output like the production of hydrogen and direct heating would be advantageous to plant economics and energy system flexibility. The civil nuclear industry is regulated around the world. This approach ensures that all the activities related to the production of power from nuclear and the hazards associated with ionising radiation are controlled in a manner which protects workers members of the public property and the environment. Nuclear safety assessments follow a rigorous process and are required as part of the Nuclear Site Licence. A fundamental requirement which is cited in the UK legislation is that the risks associated with all activities at the licensed site be reduced to As Low As Reasonably Practicable (ALARP). The principle places a requirement on duty holders to implement measures to reduce risk where doing so is considered reasonable and proportionate. The inclusion of risks for hazardous materials associated with the hydrogen production facilities need to be considered and this requires harmonisation of two different safety and regulatory governance regimes which have not previously interacted in this way. The safety demonstration for nuclear facilities is provided through the Safety Case.
Safety Calculations for Emerging Technologies
Sep 2023
Publication
As part of executing 25 hydrogen-based Power to X (PtX) projects our team of Safety consultants has completed safety and risk assessments for a number of hydrogen production developments. Drawing on this experience we will present the importance of making comparisons between hydrogen specific data sources such as HyRAM and conventional oil and gas data sets and calculation methods to ensure that project design is carried out to the most appropriate data and provides a robust solution to demonstrate risks are managed. This presentation will be based on case studies where Fire and Explosion Risk Assessments (FERA) and Quantitative Risk Assessments (QRA) were conducted. The frequency calculations for these assessments used the release frequencies and ignition probabilities provided in HyRAM. However it is noted that the HyRAM ignition probabilities are derived from a correlation from oil and gas assessments in the 1990s. The oil and gas approach has moved on from this data source and now derives ignition probabilities based on the type of facility and fluid characteristics. To address this evolution a comparison was made between the leak frequencies for equipment in hydrogen service and established oil and gas release frequencies from IOGP. In addition a comparison between the HyRAM recommended ignition probabilities and the correlations used for oil and gas (from OEUK formerly UKOOA) was conducted. By taking this approach it was confirmed that the UKOOA data was more conservative and sensitivity calculations were carried out. It was also noted that as hydrogen technologies are emerging there is a level of uncertainty around the data and comparisons must be regularly made to ensure the most appropriate basis for calculations is used.
Case Study: Quantitative Risk Assessment of Hydrogen Blended Natural Gas for an Existing Distribution Network and End-use Equipment in Fort Saskatchewan, Alberta
Sep 2023
Publication
In a first-of-its-kind project for Alberta ATCO Gas and Pipelines Ltd. (ATCO) began delivering a 5% blend of hydrogen (H2) in natural gas into a subsection of the existing Fort Saskatchewan natural gas distribution system (approximately 2100 customers). The project was commissioned in October 2022 with the intention of increasing the blend to 20% H₂ in 2023. As part of project due diligence ATCO in partnership with DNV undertook Quantitative Risk Assessments (QRAs) to understand any risks associated with the introduction of blended gas into its existing distribution system and to its customers. This paper describes key findings from the QRAs through the comparison of risks associated with H2 blended natural gas at concentrations of 5% and 20% H₂ and the current natural gas configuration. The impact of operating pressure and hydrogen blend composition formed a sensitivity study completed as part of this work. To provide context and to help interpret the results an individual risk (IR) level of 1 × 10-6 per year was utilised as a reference threshold for the limit of the ‘broadly acceptable’ risk level and juxtaposed against comparable risk scenarios. Although adding hydrogen increases the IR of ignited releases from mains services meters regulators and end user appliances the ignited release IR was always well below the broadly acceptable reference criterion for all operating pressures and blend cases considered as part of the project. The IR associated with carbon monoxide poisoning dominates the overall IR and the results demonstrate that the reduction in carbon monoxide poisoning associated with the introduction of H₂ blended natural gas negates any incremental risk associated with ignited releases due to H₂ blended gas. The paper also explains how the results of the QRA were incorporated into Engineering Assessments as per the requirements of CSA Z662:19 [1] to justify the conversion of existing natural gas infrastructure to H₂ blended gas infrastructure.
Zone Negligible Extent: Example of Specific Detailed Risk Assessment for Low Pressure Equipment in a Hydrogen Refuelling Station
Sep 2023
Publication
The MultHyFuel project aims to develop evidence-based guidelines for the safe implementation of Hydrogen Refueling Stations (HRS) in a multi-fuel context. As a part of the generation of good practice guidelines for HRS Hazardous Area Classification (HAC) methodologies were analyzed and applied to case studies representing example configurations of HRS. It has been anticipated that Negligible Extent (NE) classifications might be applicable for sections of the HRS for instance a hydrogen generator. A NE zone requires that an ignition of a flammable cloud would result in negligible consequences. In addition depending on the pressure of the system IEC 60079-10-1:2020 establishes specific requirements in order to classify the hazardous area as being of NE. One such requirement is that a zone of NE shall not be applied for releases from flammable gas systems at pressures above 2000 kPag (20 barg) unless a specific detailed risk assessment is documented. However there is no definition within the standard as to the requirements of the specific detailed risk assessment. In this work an example for a specific detailed risk assessment for the NE classification is presented:<br/>• Firstly the requirements of cloud volume dilution and background concentration for a zone of NE classification from IEC 60079-10-1:2020 are analyzed for hydrogen releases from equipment placed in a mechanically ventilated enclosure.<br/>• Secondly the consequences arising from the ignition of the localized cloud are estimated and compared to acceptable harm criteria in order to assess if negligible consequences are obtained from the scenario.<br/>• In addition a specific qualitative risk assessment for the ignition of the cloud in the enclosure was considered incorporating the estimated consequences and analyzing the available safeguards in the example system.<br/>Recommendations for the specific detailed risk assessment are proposed for this scenario with the intention to support improved definition of the requirement in future revisions of IEC 60079-10-1.
Erosive Effects of Hydrogen Jet Fires on Tunnel Structural Materials
Sep 2023
Publication
This paper presents work undertaken as part of the Hytunnel-CS project a consortium investigating safety considerations for fuel cell hydrogen (FCH) vehicles in tunnels and similar confined spaces. This test programme investigated erosive effects of an ignited high pressure hydrogen jet impinging onto tunnel structural materials specifically concrete as used for tunnel linings and asphalt road surfacing for the road itself. The chosen test conditions mimicked a high-pressure release (700 bar) from an FCH car as a result of activation of the thermal pressure relief device (TPRD) on the fuel tank. These devices typically have a release opening of 2 mm and thus a nozzle diameter of approximately 2 mm was used. The resultant releases were ignited using a propane pilot light and test samples were placed in the jet path at varying standoff distances from the release nozzle.<br/>An initial characterization test of a free unimpeded ignited jet demonstrated a rapid and intense temperature increase up to 1650 °C lasting in the order of 3 - 5 minutes for that fuel inventory (4 kg hydrogen). Five tests were carried out where the ignited jet was impinged onto five structural samples. It was found that erosion occurred in the concrete samples where no fire mitigation namely addition of polypropylene fibres was applied. The road-surface sample was found to become molten but did not progress to combustion.<br/>Post-test material analysis including compressive strength and thermal conductivity measurements was carried out on some of the concrete samples to investigate whether structural deformities had occurred within the sample microstructure. The results suggested that the erosive damage caused by the hydrogen jet was mostly superficial and as such did not present an increased fire risk to the structural integrity to that of conventional hydrocarbon fires i.e. those that would result from petrol or diesel fuel tank releases. In terms of fire resistance standards it is suggested that current fire mitigation strategies and structural testing standards would be adequate for hydrogen vehicles on the road network.
Purging Hydrogen Distribution Pipelines: Literature Review, Description of Recent Experiments and Proposed Future Work
Sep 2023
Publication
The aim of the H21 project is to undertake measurements analysis and field trials to support the safe repurposing of Great Britain’s natural gas distribution network for hydrogen. As part of this project work has been ongoing to identify aspects of existing natural gas procedures that will need to be modified for hydrogen and to support the development of new procedures. This has included a review of the scientific basis of current displacement purging practices analysis of the potential implications of switching from natural gas to hydrogen and experimental support work. The reduced density and viscosity of hydrogen means that minimum purging velocities should (in principle) be higher for hydrogen to avoid stratification and ensure adequate removal of the purged gas during pipeline purging operations. A complicating factor is the high molecular diffusivity of hydrogen (roughly three times that of natural gas) which causes hydrogen to mix over short distances more rapidly than natural gas. Current models for pipeline purging do not take into account the mixing effect related to molecular diffusion. The wider flammable limits lower ignition energy and greater potential for combustion to transition from deflagration to detonation with hydrogen means that indirect purging with nitrogen is currently being investigated for distribution pipelines. This paper reviews the ongoing analysis of hydrogen pipeline purging and discusses a potential future scientific programme of work aimed at developing a new pipeline purging model that accounts for molecular diffusion effects.
Hydrogen Dispersion Following Blowdown Releases into a Tunnel
Sep 2023
Publication
This paper presents work undertaken by the HSE as part of the Hytunnel-CS project a consortium investigating safety considerations for fuel cell hydrogen (FCH) vehicles in tunnels and similar confined spaces. The test programme investigating hydrogen dispersion in tunnels involved simulating releases analogous to Thermally activated Pressure Relief Devices (TPRDs) typically found on hydrogen vehicles into the HSE Tunnel facility. The releases were scaled and based upon four scenarios: cars buses and two different train designs. The basis for this scaling was the size of the tunnel and the expected initial mass flow rates of the releases scenarios. The results of the 12 tests completed have been analysed in two ways: the initial mass flow rates of the tests were calculated based upon facility measurements and the Able-Noble equations of state for comparison to the intended initial flow rate; and observations of the hydrogen dispersion in the tunnel were made based on 15 hydrogen sensors arrayed along the tunnel. The calculated mass flow rates showed reasonable agreement with the intended initial conditions showing that the scaling methodology can be used to interpret the data based on the full-scale tunnel of interest. Observations of the hydrogen dispersion show an initial turbulent mixing followed by a movement of the mixed hydrogen/air cloud down the tunnel. No vertical stratification of the cloud was observed but this effect could be possible in longer tunnels or tunnels with larger diameters. Higher ventilation rates in the tunnel resulted in a reduction of the residence time of the hydrogen and a slight increase in the dilution.
Sudden Releases of Hydrogen into a Tunnel
Sep 2023
Publication
This paper presents work undertaken by the HSE as part of the Hytunnel-CS project a consortium investigating safety considerations for fuel cell hydrogen (FCH) vehicles in tunnels and similar confined spaces. The sudden failure of a pressurised hydrogen vessel was identified as a scenario of concern due to the severity of the consequences associated with such an event. In order to investigate this scenario experimentally HSE designed a bespoke and reusable ‘sudden release’ vessel. This paper presents an overview of the vessel and the results of a series of 13 tests whereby hydrogen was released from the bespoke vessel into a tunnel at pressures up to 65 MPa. The starting pressure and the volume of hydrogen in the vessel were altered throughout the campaign. Four of the tests also included congestion in the tunnel. The tests reliably autoignited. Overpressure measurements and flame arrival times measured with exposed-tip thermocouples enabled analysis of the severity of the events. A high-pressure fast-acting pressure transducer in the body of the vessel showed the pressure decay in the vessel which shows that 90% of the hydrogen was evacuated in between 1.8 and 3.2 ms (depending on the hydrogen inventory). Schlieren flow imagery was also used at the release point of the hydrogen showing the progression of the shock front following initiation of the tests. An assessment of the footage shows an estimated initial velocity of Mach 3.9 at 0.4 m from the release point. Based on this an ignition mechanism is proposed based upon the temperature behind the initial shock front.
Enhancing Safety of Liquid and Vaporised Hydrogen Transfer Technologies in Public Areas for Mobile Applications
Sep 2023
Publication
Federico Ustolin,
Donatella Cirrone,
Vladimir V. Molkov,
Dmitry Makarov,
Alexandros G. Venetsanos,
Stella G. Giannissi,
Giordano Emrys Scarponi,
Alessandro Tugnoli,
Ernesto Salzano,
Valerio Cozzani,
Daniela Lindner,
Birgit Gobereit,
Bernhard Linseisen,
Stuart J. Hawksworth,
Thomas Jordan,
Mike Kuznetsov,
Simon Jallais and
Olga Aneziris
International standards related to cryogenic hydrogen transferring technologies for mobile applications (filling of trucks ships stationary tanks) are missing and there is lack of experience. The European project ELVHYS (Enhancing safety of liquid and vaporized hydrogen transfer technologies in public areas for mobile applications) aims to provide indications on inherently safer and efficient cryogenic hydrogen technologies and protocols in mobile applications by proposing innovative safety strategies which are the results of a detailed risk analysis. This is carried out by applying an inter-disciplinary approach to study both the cryogenic hydrogen transferring procedures and the phenomena that may arise from the loss of containment of a piece of equipment containing hydrogen. ELVHYS will provide critical inputs for the development of international standards by creating inherently safer and optimized procedures and guidelines for cryogenic hydrogen transferring technologies thus increasing their safety level and efficiency. The aim of this paper is twofold: present the state of the art of liquid hydrogen transfer technologies by focusing on previous research projects such as PRESLHY and introduce the objectives and methods planned in the new EU project ELVHYS.
CFD Modelling of Startup Fuelling Phase Accounting for All Hydrogen Refuelling Station Components
Sep 2023
Publication
Further development of hydrogen-fuelled transport and associated infrastructure requires fundamentally based validated and publicly accepted models for fuelling protocol development particularly for heavy-duty transport applications where protocols are not available yet. This study aims to use computational fluid dynamics (CFD) for modelling the entire hydrogen refuelling station (HRS) including all its components starting from high-pressure (HP) tanks a mass flow meter pressure control valve (PCV) a heat exchanger (HE) nozzle hose breakaway and up to 3 separate onboard tanks. The paper focuses on the initial phase of the refuelling procedure in which the main purpose is to check for leaks in the fuelling line and determine if it is safe to start fuelling. The simulation results are validated against the only publicly available data on hydrogen fuelling by Kuroki and co-authors (2021) from the NREL hydrogen fuelling station experiment. The simulation results – mass flow rate dynamics as well as pressure and temperature at different station locations - show good agreement with the measured experimental data. The development of such models is crucial for the further advancement of hydrogen-fuelled transport and infrastructure and this study presents a step towards this goal.
Engineering Models for Refueling Protocol Development: Validation and Recommendations
Sep 2023
Publication
Fouad Ammouri,
Nicola Benvenuti,
Elena Vyazmina,
Vincent Ren,
Guillaume Lodier,
Quentin Nouvelot,
Thomas Guewouo,
Dorine Crouslé,
Rony Tawk,
Nicholas Hart,
Steve Mathison,
Taichi Kuroki,
Spencer Quong,
Antonio Ruiz,
Alexander Grab,
Alexander Kvasnicka,
Benoit Poulet,
Christopher Kutz and
Martin Zerta
The PRHYDE project (PRotocol for heavy duty HYDrogEn refueling) funded by the Clean Hydrogen partnership aims at developing recommendations for heavy-duty refueling protocols used for future standardization activities for trucks and other heavy duty transport systems applying hydrogen technologies. Development of a protocol requires a validated approach. Due to the limited time and budget the experimental data cannot cover the whole possible ranges of protocol parameters such as initial vehicle pressure and temperature ambient and precooling temperatures pressure ramp refueling time hardware specifications etc. Hence a validated numerical tool is essential for a safe and efficient protocol development. For this purpose engineering tools are used. They give good results in a very reasonable computation time of several seconds or minutes. These tools provide the heat parameters estimation in the gas (volume average temperature) and 1D temperature distribution in the tank wall. The following models were used SOFIL (Air Liquide tool) HyFill (by ENGIE) and H2Fills (open access code by NREL). The comparison of modelling results and experimental data demonstrated a good capability of codes to predict the evolution of average gas temperature in function of time. Some recommendations on model validation for the future protocol development are given.
UK HSE Hydrogen for Heating Evidence Review Process
Sep 2023
Publication
As part of the UK Government’s Net Zero targets to tackle Climate Change the Health and Safety Executive (HSE) aims to reach an authoritative view on the safety of using 100% hydrogen for heating across the UK to feed into Government policy decisions by the mid-2020s. This paper describes the background and process of a programme of work led by HSE in support of the Department for Energy Security and Net Zero (formerly BEIS) that will inform strategic policy decisions by 2026. The strategic framework of HSE’s programme of work was defined between BEIS and HSE. HSE’s programme of work follows on from a previous project which engaged with HSE policy regulatory and scientific colleagues working with industry stakeholders identifying knowledge gaps for the safe distribution storage and use of hydrogen gas in domestic industrial and commercial premises. These knowledge gaps were subsequently used in discussions with stakeholders to prioritise research projects and evidence gathering exercises. To review this scientific evidence HSE developed a review framework and convened Evidence Review Groups (ERGs) to cover all evidence areas encompassing topics such as quantified risk assessment material compatibility and operational procedures. These ERGs include representation from relevant divisions across HSE (policy regulation and science). The paper explains the structure of HSE’s input into the hydrogen for heating programme the ERG process and timelines along with the proposed outputs. Additional activities have been undertaken by HSE within the programme to highlight specific issues in support of the review process which will also be discussed.
Numerical Simulations of the Critical Diameter and Flame Stability for the Hydrogen Jet Flames
Sep 2023
Publication
This study focuses on development of a CFD model able to simulate the experimentally observed critical nozzle diameter for hydrogen non-premixed flames. The critical diameter represents the minimum nozzle size through which a free jet flame will remain stable at all driving pressures. Hydrogen non-premixed flames will not blow-out at diameters equal to or greater than the critical diameter. Accurate simulation of this parameter is important for assessment of thermally activated pressure relief device (TPRD) performance during hydrogen blowdown from a storage tank. At TPRD diameters below the critical value there is potential for a hydrogen jet flame to blow-out as the storage tank vents potentially leading to hydrogen accumulation in an indoor release scenario. Previous experimental studies have indicated that the critical diameter for hydrogen is approximately 1 mm. In this study flame stability is considered across a range of diameters and overpressures from 0.1 mm to 2 mm and from 0.2 MPa to 20 MPa respectively. The impact of turbulent Schmidt number Sct which is the ratio of momentum diffusivity (kinematic viscosity) and mass diffusivity on the hydrogen concentration profile in the region near the nozzle exit and subsequent influence on critical diameter was investigated and discussed. For lower Sct values the enhanced mass mixing resulted in smaller predicted critical diameters. The use of value Sct=0.61 in the model demonstrated the best agreement with experimental values of the critical diameter. The model reproduced the critical diameter of 1 mm and then was applied to predict flame stability for under-expanded hydrogen jets.
Ignition and Flow Stopping Considerations for the Transmission of Hydrogen in the Existing Natural Gas Network
Sep 2023
Publication
This work formed part of the H21 programme whose objective is to reach the point whereby it is feasible to convert the existing natural gas (NG) distribution network to 100% hydrogen (H2) and provide a contribution to decarbonising the UK’s heat and power sectors with the focus on decarbonised fuel at point of use. Hydrogen has an ATEX Gas Group of IIC compared to IIA for natural gas which means further precautions are necessary to prevent the ignition of hydrogen during network operations. Both electrostatic and friction ignition risks were considered. Network operations considered include electrostatic precautions for polyethylene (PE) pipe and cutting and drilling of metallic pipes. As a result of the updated basis of safety from ignition considerations existing flow stopping methods were reviewed to see if they were compatible. Commonly used flow stopping methods were tested under laboratory conditions with hydrogen following the methodologies specified in the Gas Industry Standards (GIS). A new basis of safety for flow stopping has been proposed that looks at the flow past the secondary stop as double isolations are recommended for use with hydrogen.
Investigation of the Suitability of Viper: Blast CFD Software for Hydrogen and Vapor Cloud Explosions
Sep 2023
Publication
Many simplified methods for estimating blast loads from a hydrogen or vapor cloud explosion are unable to take into account the accurate geometry of confining spaces obstacles or landscape that may significantly interact with the blast wave and influence the strength of blast loads. Computation fluid dynamics (CFD) software Viper::Blast which was originally developed for the simulation of the detonation of high explosives is able to quickly and easily model geometry for blast analyses however its use for vapor cloud explosions and deflagrations is not well established. This paper describes the results of an investigation into the suitability of Viper::Blast for use in modeling hydrogen deflagration and detonation events from various experiments in literature. Detonation events have been captured with a high degree of detail and relatively little uncertainty in inputs while deflagration events are significantly more complex. An approach is proposed that may allow for a reasonable bounding of uncertainty potentially leading to an approach to CFD-based Monte Carlo analyses that are able to address a problem’s true geometry while remaining reasonably pragmatic in terms of run-time and computational investment. This will allow further exploration of practical CFD application to inform hydrogen safety in the engineering design assessment and management of energy mobility and transport systems infrastructure and operations.
The Economical Repurposing Pipeliness to Hydrogen - Why Performance Testing of Representative Line Pipes is Key?
Sep 2023
Publication
The introduction of hydrogen in natural gas pipeline systems introduces integrity challenges due to the nature of interactions between hydrogen and line pipe steel materials. However not every natural gas pipeline is equal in regards to the challenges potentially posed by the repurposing to hydrogen. Existing codes and practices penalise high-grade materials on the basis of a perceived higher susceptibility to hydrogen embrittlement in regards to their increased strength. This philosophy challenges the realisation of a hydrogen economy because it puts at economical and technical risk the conversion of almost half of the natural gas transmission systems in western countries.
The paper addresses the question whether pipe grade is actually a good proxy to strength and predictor to assess the performance of steel line pipes in hydrogen. Drivers that could affect the suitability of pipeline conversion in hydrogen from an integrity management perspective and industry experience of other hydrogen-charging applications are reviewed. In doing so the paper challenges the basis of the assumption that low-grade steels (up to X52 / L360) are automatically safer for hydrogen repurposing while at the other end of the spectrum higher-grade materials (>X52 / L360) are inevitably less suitable for hydrogen service.
Ultimately the paper discusses that materials sampling and testing of representative line pipes populations should be placed at the core of hydrogen repurposing strategies in order to safely address conversion and to maximize the hydrogen chain value. The paper addresses alternatives to make the sampling smart and cost-effective.
The paper addresses the question whether pipe grade is actually a good proxy to strength and predictor to assess the performance of steel line pipes in hydrogen. Drivers that could affect the suitability of pipeline conversion in hydrogen from an integrity management perspective and industry experience of other hydrogen-charging applications are reviewed. In doing so the paper challenges the basis of the assumption that low-grade steels (up to X52 / L360) are automatically safer for hydrogen repurposing while at the other end of the spectrum higher-grade materials (>X52 / L360) are inevitably less suitable for hydrogen service.
Ultimately the paper discusses that materials sampling and testing of representative line pipes populations should be placed at the core of hydrogen repurposing strategies in order to safely address conversion and to maximize the hydrogen chain value. The paper addresses alternatives to make the sampling smart and cost-effective.
No more items...