{"title":"High-efficient boil-off gas storage using low-temperature activated carbon adsorption","authors":"J.K. Wu , Y.X. Zhang , M. Yu , L. Jiang","doi":"10.1016/j.jgsce.2025.205765","DOIUrl":"10.1016/j.jgsce.2025.205765","url":null,"abstract":"<div><div>Boil-off gas (BOG) leakage poses significant challenges during LNG storage and transportation, since it leads to resource waste, environmental damage, and safety risks. Compared with widely used cryogenic re-liquefaction in BOG recovery, low-temperature adsorption has attracted increasing attention due to relatively low equipment investment and energy consumption. This work aims to investigate the feasibility of cryogenic adsorption for BOG recovery. Biomass-derived coconut shell activated carbon materials for low-temperature methane adsorption are prepared, and their BOG recovery performance are systematically investigated. Results indicate that KOH activated coconut shell activated carbon (CHCS-KOH) has higher specific surface area (1710.28 m<sup>2</sup>/g) and optimal microporous structure for methane adsorption, achieving a remarkable methane adsorption capacity of14.37 mmol/g at the cryogenic temperature of 133 K, which is rarely reached in previous test. A modified D-A model is successfully fitted for the first time to describe methane adsorption across a wide temperature range from 133 K to 293 K. Based on CHCS-KOH, a BOG adsorption recovery system is established and its performance is analyzed. The optimal storage temperature is determined to be 160 K and minimum recovery energy consumption is 0.5645 kW h/kg with a recovery rate of 89.47 %. These findings may provide new methods for the research on low temperature methane adsorption and BOG recovery.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"144 ","pages":"Article 205765"},"PeriodicalIF":5.5,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144878503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xu Li , Han Jia , Qiuxia Wang , Yuanbo Wang , Fangning Fan , Bowen Wang , Qiang Wang , Yurong Zhao , Pan Huang
{"title":"Molecular insights into the stability of CO2 hydrate in variable-diameter nano-slit","authors":"Xu Li , Han Jia , Qiuxia Wang , Yuanbo Wang , Fangning Fan , Bowen Wang , Qiang Wang , Yurong Zhao , Pan Huang","doi":"10.1016/j.jgsce.2025.205763","DOIUrl":"10.1016/j.jgsce.2025.205763","url":null,"abstract":"<div><div>Most literatures focused on the stability of CO<sub>2</sub> hydrate in uniform-diameter nano-slits, while variable-diameter nano-slits may be more prevalent in the realistic environments for CO<sub>2</sub> storage processes. This study employs molecular dynamics (MD) simulations to systematically explore the effects of various factors (disordered water, slit size, and wettability) on hydrate stability in variable-diameter nano-slits. It is revealed that the variable-diameter nano-slit affects the activity of disordered water, rather than altering the hydrate crystal structure, to dominate the hydrate stability. The presence of disordered water decreases hydrate stability, with the melting point dropping from 282 K to 269 K when disordered water in large slits, and further declining to 267 K when it in small slits. The Vertical surfaces in the nano-slits induce heterogeneity in disordered water activity, and its proportion dominates the further depression of melting points for hydrates in large slits. The slit surface-water interaction caused by the wettability variation hardly impact the hydrate stability, whereas the differences in nanobubbles distribution significantly influence the stability of hydrates in the small slits. This study firstly offers valuable insights into the complex interactions affecting CO<sub>2</sub> hydrate stability in more realistic porous media environments, uncovering the mechanisms by which geometric heterogeneity and interfacial behavior influence hydrate stability.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"144 ","pages":"Article 205763"},"PeriodicalIF":5.5,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144889194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Hydrogen migration in olivine based on first principles study: Implications for underground hydrogen storage","authors":"Yu Huang , Lei Liu , Le Hu , Hong Liu","doi":"10.1016/j.jgsce.2025.205766","DOIUrl":"10.1016/j.jgsce.2025.205766","url":null,"abstract":"<div><div>Understanding the diffusion behavior of hydrogen in subsurface olivine can elucidate the kinetic processes governing H<sub>2</sub> migration, enrichment, and depletion, thereby establishing a theoretical foundation for deciphering underground hydrogen storage (UHS) mechanisms in geological formations and advancing the exploration, development, and utilization of subsurface H<sub>2</sub> resources. This study investigates H<sub>2</sub> diffusion in olivine using climbing image nudged elastic band (CI-NEB) method based on density functional theory (DFT). Our results reveal pronounced anisotropy in H<sub>2</sub> diffusion activation energies for both fayalite (Fe<sub>2</sub>SiO<sub>4</sub>) and forsterite (Mg<sub>2</sub>SiO<sub>4</sub>) under ambient pressure, with the [010] direction exhibiting the highest barriers, and fayalite demonstrates higher activation energies than forsterite. Expanding the pressure range to encompass the entire upper mantle, our calculations for pressure-dependent H<sub>2</sub> diffusion in forsterite show excellent agreement with prior ab initio molecular dynamics (AIMD) studies, validating the reliability of our methodology. To assess hydrogen storage capacity, we calculated H<sub>2</sub> diffusion distances in olivine over Earth's geological timescale. The results demonstrate meter-scale confinement of H<sub>2</sub> migration, confirming olivine's exceptional hydrogen retention capability. Notably, fayalite exhibits far shorter diffusion distances than forsterite, indicating superior storage capacity in Fe-rich olivine. For H<sub>2</sub> extraction, thermal extraction simulations for 100 μm–2000 μm crystals under three heating rates reveal temperature thresholds: under moderate heating (10 °C/Ma), initial H<sub>2</sub> release requires heating to 135 °C (fayalite) and 112 °C (forsterite) for 100 μm crystals, while complete extraction necessitates 190 °C and 162 °C, respectively. These findings establish olivine, particularly fayalite, as a natural hydrogen reservoir and provide critical parameters for evaluating hydrogen storage and recovery in geologic systems.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"144 ","pages":"Article 205766"},"PeriodicalIF":5.5,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Parisa Ebrahimi , Anand Kumar , Mohammed J. Al-Marri
{"title":"Understanding the formation of active site in copper ceria system for carbon dioxide catalytic conversion","authors":"Parisa Ebrahimi , Anand Kumar , Mohammed J. Al-Marri","doi":"10.1016/j.jgsce.2025.205764","DOIUrl":"10.1016/j.jgsce.2025.205764","url":null,"abstract":"<div><div>Copper-based catalysts, particularly those supported by ceria (CeO<sub>2</sub>), provide a cost-effective substitute for noble metals in hydrogenation reactions. The interaction between Cu and CeO<sub>2</sub> improves dispersion and generates essential active sites, such as Cu<sup>+</sup> and oxygen vacancies, vital for catalytic efficiency. This study explores the creation of active sites in Cu/CeO<sub>2</sub> catalysts through adjustments in metal content and calcination conditions. The findings reveal that the 2 wt%Cu/CeO<sub>2</sub> catalyst calcined at 600 °C achieved the highest CO<sub>2</sub> conversion via reverse water gas shift reaction (RWGS) to CO, approximately 60 % at 600 °C, with minimal coke formation. Additionally, the catalyst also exhibited reactivity in the dry reforming of methane at elevated temperatures (above 800 °C). The characterization data suggest that the strong interaction among finely dispersed CuO and the CeO<sub>2</sub> support enhances electron transfer, leading to a higher density of surface oxygen vacancies and Cu<sup>+</sup> species, which in turn promotes the redox cycle. The density of Cu<sup>+</sup>/(Cu<sup>+</sup>+Cu<sup>2+</sup>) and surface oxygen vacancy correlates very well with the synthesis conditions and catalytic activity towards CO<sub>2</sub> conversion. The results suggest that Cu loading and calcination temperature in Cu/CeO<sub>2</sub> system could significantly enhance the presence of active sites for effective CO<sub>2</sub> hydrogenation.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"144 ","pages":"Article 205764"},"PeriodicalIF":5.5,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144878504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multiscale insights into CO2/CH4 competitive adsorption and diffusion: Molecular dynamics and pore-scale modeling for enhanced shale gas recovery and carbon storage optimization","authors":"Nong Kang, Feng Yang, Peixing Xu, Sijia Nie","doi":"10.1016/j.jgsce.2025.205761","DOIUrl":"10.1016/j.jgsce.2025.205761","url":null,"abstract":"<div><div>CO<sub>2</sub> injection in shale reservoirs is highly promising and feasible in enhanced shale gas recovery and carbon capture and storage (CCS). It is essential to fully understand the complex competitive adsorption and diffusive behaviors of CO<sub>2</sub> and CH<sub>4</sub> in shale reservoirs at multiscale levels. This study integrates molecular dynamics (MD) and pore-scale simulations on nano-CT-reconstructed 3D shale matrices to unravel CO<sub>2</sub>/CH<sub>4</sub> competitive adsorption and diffusion across multiple scales. MD results demonstrate the preferential adsorption of CO<sub>2</sub> over CH<sub>4</sub>, with binding affinities ranked: organic matter > SiO<sub>2</sub> > kaolinite. The confinement effects in small nanopores (4 nm) amplify the density of CO<sub>2</sub> adsorption by 60–70 % compared to larger pores (10 and 20 nm), while the adsorption/desorption rates derived from MD simulation and the diffusion coefficients calculated from MSD govern the transport dynamics. The uniform porous model (UPM) achieves 43–64 % CO<sub>2</sub> recovery at optimized CO<sub>2</sub> concentrations (300–600 mol/m<sup>3</sup>), while the fractured porous model (FPM) exhibits lower recovery due to preferential flow bypassing adsorbed CO<sub>2</sub>. The diminishing returns beyond 600 mol/m<sup>3</sup> highlight a critical balance between methane production and injection of CO<sub>2</sub>.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"144 ","pages":"Article 205761"},"PeriodicalIF":5.5,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144867136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qing Liu , Tianyu Chen , Hui Zhang , Ke Xu , Xianbao Zheng , Zhiguo Wang , Chang Hui , Zhejun Pan
{"title":"Experimental investigation of permeability evolution in deep reservoirs under true triaxial stress: A review","authors":"Qing Liu , Tianyu Chen , Hui Zhang , Ke Xu , Xianbao Zheng , Zhiguo Wang , Chang Hui , Zhejun Pan","doi":"10.1016/j.jgsce.2025.205739","DOIUrl":"10.1016/j.jgsce.2025.205739","url":null,"abstract":"<div><div>Despite its economic significance, hydrocarbon production from deep and ultra-deep formations poses considerable technological and scientific challenges. The permeability of reservoirs is a critical indicator for assessing the feasibility of commercial oil and gas exploitation, particularly for deep and ultra-deep reservoirs characterized by high geo-stress and an anisotropic stress state (<em>σ</em><sub>1</sub> > <em>σ</em><sub>2</sub> > <em>σ</em><sub>3</sub>). This review examines recent studies on permeability assessments under true triaxial stress conditions and highlighted the latest advancements in this field. We first outline current mainstream true triaxial permeability testing apparatuses and methodologies. Thereafter, the permeability response of rocks, particularly homogeneous rocks, under true triaxial stress conditions is analyzed, with particular emphasis on the influence of the intermediate principal stress. Furthermore, various true triaxial stress loading paths aimed at different research objectives and their corresponding permeability evolution behaviors are thoroughly introduced. Subsequently, we investigate the permeability characteristics of anisotropic rocks such as shale and coal, considering the coupling effect of textural features such as bedding and true triaxial stress on permeability evolution. Throughout this investigation, the permeability evolution laws exhibited by various types of rocks across the full stress-strain stage under true triaxial stress are comprehensively analyzed. Finally, specific future research directions and challenges in true triaxial permeability studies are outlined, with a focus on their applicability to deep resource exploitation engineering. This review presents an overview of the current state of true triaxial permeability testing and offers novel insights into permeability characterization in deep and ultra-deep reservoirs.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"144 ","pages":"Article 205739"},"PeriodicalIF":5.5,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144889196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xi Wang , Kaibang Liu , Shouyi Ma , Linan Guan , Zherui Chen , Yan Qin , Jingyue Sun , Cong Chen
{"title":"Investigation of hydrate formation and flow characteristics within multiphase transmission pipelines employing a constant pressure visualization loop system","authors":"Xi Wang , Kaibang Liu , Shouyi Ma , Linan Guan , Zherui Chen , Yan Qin , Jingyue Sun , Cong Chen","doi":"10.1016/j.jgsce.2025.205747","DOIUrl":"10.1016/j.jgsce.2025.205747","url":null,"abstract":"<div><div>Hydrate blockages during oil and gas transportation severely affect flow safety. An innovative, fully visual flow loop was utilized to systematically evaluate and quantify the individual effects of pressure, temperature, flow velocity, and liquid loading on hydrate formation, flow characteristics, and morphological evolution. The results indicate that hydrate growth progresses through the stages of initial formation, slurry stable flow, and aggregation and blocking, with the water conversion fraction and differential pressure exhibiting pronounced stage-dependent evolution features. Increased pressure augments the fugacity gradient, thereby reducing the hydrate formation time and blocking time, exacerbating particle aggregation, and facilitating hydrate generation. At constant pressure, high subcooling accelerates gas consumption and lengthens hydrate formation time, promoting the development of microporous aggregate network structures. The water conversion fraction increases with subcooling but remains insensitive to variations in subcooling during the blocking stage. A critical flow velocity exists, above which hydrate can continue to be transported in suspension in the main pipeline, although deadlegs remain susceptible to blockage. Furthermore, flow velocities exceeding 0.27 m/s can postpone blockage when below the critical threshold. High liquid loading delays hydrate formation time but shortens blocking time, and the maximum water conversion fraction occurs at a liquid loading of 60 vol%. During the slurry stable flow stage, hydrate conversion above this critical value is governed by particle aggregation and continued hydrate formation. These experimental findings advance the understanding of hydrate behavior in multiphase flow systems under constant pressure, providing a foundation for improving risk assessment and flow assurance strategies.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"144 ","pages":"Article 205747"},"PeriodicalIF":5.5,"publicationDate":"2025-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144860848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Min Qin , Qin Wang , Shijian Zhang , Xinhui Jiang , Sijia Chen , Tengjiao He , Kexi Liao
{"title":"Underground hydrogen storage:An overview of material damage under the synergistic effect of sulfate reducing bacteria and hydrogen gas","authors":"Min Qin , Qin Wang , Shijian Zhang , Xinhui Jiang , Sijia Chen , Tengjiao He , Kexi Liao","doi":"10.1016/j.jgsce.2025.205750","DOIUrl":"10.1016/j.jgsce.2025.205750","url":null,"abstract":"<div><div>Under the background of \"dual-carbon\" strategy, with the transformation of energy structure to cleaner and lower carbon, hydrogen energy, as a green and efficient secondary energy carrier, has attracted much attention for its large-scale storage technology. However, the coexistence of high-pressure hydrogen and sulfate-reducing bacteria (SRB) in underground hydrogen storage (UHS) environments leads to synergistic damage from microbial corrosion and hydrogen embrittlement (HE), seriously threatening the structural integrity and safe operation of hydrogen storage facilities. This study first introduces the types of UHS reservoirs and the complex environment where SRB coexist with H<sub>2</sub>, and then elaborates on the microbial corrosion mechanism of SRB in depth, focusing on the regulatory role of H<sub>2</sub> in the growth and metabolism of SRB. Then, the failure mechanisms of metallic materials in a high-pressure, pure hydrogen environment are summarized, including HE, hydrogen-induced cracking (HIC) and hydrogen blister (HB). The interaction mechanism between SRB biofilms/corrosion product films and hydrogen permeation behavior is analyzed, especially in an UHS environment. Based on the existing research, three research perspectives on the mechanism of multi-physical field coupled hydrogen damage, SRB-H<sub>2</sub> synergistic mechanism, and HE protection measures are proposed to ensure the safe operation of UHS facilities.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"143 ","pages":"Article 205750"},"PeriodicalIF":5.5,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144780389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Impact of oxide nanoparticles as hydrate inhibitors on polymer rheology for low-temperature stimulation of gas hydrate reservoirs","authors":"Isaac Wilson , Shanker Krishna","doi":"10.1016/j.jgsce.2025.205749","DOIUrl":"10.1016/j.jgsce.2025.205749","url":null,"abstract":"<div><div>Gas hydrate production faces several challenges, including low sediment permeability and the potential for rapid hydrate reformation during depressurization-based recovery. While hydraulic fracturing offers a promising means to enhance permeability and stimulate gas flow, its success in hydrate-bearing sediments depends on the performance and stability of fracturing fluids under low-temperature conditions. This study does not investigate hydrate formation kinetics directly; rather, it focuses on evaluating the compatibility of fracturing fluids integrated with oxide nanoparticles, specifically alumina (Al<sub>2</sub>O<sub>3</sub>), silica (SiO<sub>2</sub>), and zinc oxide (ZnO), that are known to influence hydrate behavior. The objective is to assess how these nanoparticles affect the rheological properties, structural integrity, and stability of guar-based linear and crosslinked gels. Results indicate that all nanoparticles improved fluid viscosity and stability at optimal concentrations, with ZnO demonstrating the most pronounced enhancement. ZnO-integrated gels exhibited superior long-term resistance to syneresis and structural degradation, followed by Al<sub>2</sub>O<sub>3</sub>, while SiO<sub>2</sub> showed negligible impact compared to the reference fluid. In viscoelastic testing, SiO<sub>2</sub> performed best at low concentrations in linear gels, whereas ZnO tended to reduce elasticity in crosslinked systems. A comparative summary of rheological performance and gel stability is presented to guide nanoparticle selection for field applications. This work represents one of the first comprehensive studies on the rheological compatibility of nanoparticles as gas hydrate kinetic modifiers with polymer-based fracturing fluids, addressing a key knowledge gap in the application of stimulation technologies to hydrate-bearing sediments. The findings provide critical insights into how nanoparticle type and concentration affect gel behavior at low temperatures, offering a foundation for designing next-generation, multifunctional fracturing fluids for gas hydrate reservoirs. By systematically linking inhibitor integration with gel performance, this study supports the advancement of sustainable and effective hydrate production techniques, marking a significant step toward practical field implementation.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"143 ","pages":"Article 205749"},"PeriodicalIF":5.5,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144766535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Samin Rhythm, Ramadan Ahmed, Nayem Ahmed, Michael Gyaabeng, Catalin Teodoriu
{"title":"Experimental study of the impact of hydrogen embrittlement on the ductility of natural gas pipeline steels","authors":"Samin Rhythm, Ramadan Ahmed, Nayem Ahmed, Michael Gyaabeng, Catalin Teodoriu","doi":"10.1016/j.jgsce.2025.205746","DOIUrl":"10.1016/j.jgsce.2025.205746","url":null,"abstract":"<div><div>The mechanical integrity of low-carbon and low-alloy steels is significantly affected by hydrogen embrittlement (HE), particularly in hydrogen-rich environments. Despite extensive research on HE, investigations involving hydrogen-natural gas blends remain limited. This study addresses this gap by examining the effects of HE on the tensile properties of X52, X60, and X70 pipeline steels.</div><div>The study evaluates the reduction of area (RA) and elongation in these steels under exposure to pure hydrogen at pressures ranging from 0 to 6.9 MPa and hydrogen-natural gas blends with hydrogen concentrations between 0 % and 100 % by volume. All experiments were conducted at ambient temperature to isolate the effects of hydrogen-induced embrittlement. The susceptibility of the selected pipeline steels to HE was assessed in both pure hydrogen and mixed gas environments.</div><div>The results from pure hydrogen exposure reveal a systematic decline in ductility with increasing pressure, as evidenced by reductions in RA and elongation. This trend underscores the critical need for HE mitigation strategies in hydrogen-exposed pipeline materials. In contrast, the mixed gas experiments exhibited distinct RA and elongation variations with increasing hydrogen concentration. The highest RA value in pure hydrogen was observed at zero hydrogen pressure, whereas in the blended gas environment, the maximum RA was recorded at approximately 7.5 % hydrogen concentration.</div><div>Comparative analysis under equivalent hydrogen partial pressure conditions indicates that embrittlement is less severe in mixed gas than in pure hydrogen at low partial pressures (∼0.52 MPa). A similar trend was observed in elongation measurements. However, at hydrogen concentrations exceeding 20 %, embrittlement effects in mixed gas surpassed those observed in pure hydrogen under equivalent partial pressure conditions. These findings provide critical insights into the interaction between hydrogen exposure and tensile properties, contributing to the development of hydrogen-compatible pipeline materials.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"143 ","pages":"Article 205746"},"PeriodicalIF":5.5,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144757916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}