Fuel最新文献

{"title":"Efficient in-situ transfer hydrogenation of palmitic acid into alkanes over Ni/CexZr1-xO2 solid solution catalysts in aqueous medium with methanol as the hydrogen donor","authors":"Yuhao Yan ,&nbsp;Daxin Jiang ,&nbsp;Rui Li ,&nbsp;Jie Zhao ,&nbsp;Rumin Zheng ,&nbsp;Xianliang Song ,&nbsp;Yulong Wu","doi":"10.1016/j.fuel.2025.135141","DOIUrl":"10.1016/j.fuel.2025.135141","url":null,"abstract":"<div><div>Compared to adding high-purity H₂, converting microalgae-oil into high-quality fuel through in-situ transfer hydrogenation is more economical and safer. Multiple Ni/Ce_xZr_1-xO₂ catalysts were prepared using the co-precipitation method and evaluated for in-situ transfer hydrogenation for palmitic acid (PA) with methanol as the hydrogen donor. The results indicated that, compared to Ni/ZrO₂ and Ni/CeO₂, the catalytic activity of all Ni/Ce_xZr_1-xO₂ has been significantly improved by the formation of solid solutions. Wherein, Ni/Ce_0.8Zr_0.2O₂ possessed the best catalytic effect, surpassing commercial Pt/C. And under optimized conditions (330 °C, 4 h, and 9.6 mmol methanol), Ni/Ce_0.8Zr_0.2O₂ (15 wt% Ni-loading) achieved the highest palmitic acid conversion of 93.6 % and alkane yield of 90.4 %. The excellent performance of Ni/Ce_0.8Zr_0.2O₂ was attributed to the combined effect of larger BET surface area, smaller particle size, stronger H-adsorption capacity and spillover hydrogen effect, more surface defects and oxygen vacancy concentrations. The stability testing showed that after four cycles, the main products over Ni/Ce_0.8Zr_0.2O₂ changed from alkanes to methyl palmitate. And the catalyst deactivation was caused by multiple factors such as the decomposition of Ce_0.8Zr_0.2O₂, aggregation and leaching of Ni, and carbon deposition.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"394 ","pages":"Article 135141"},"PeriodicalIF":6.7,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluid transport driven by geothermal gradient and its impact on the storage characteristics of CO2 hydrates","authors":"Lei Yang ,&nbsp;Riliang Xu ,&nbsp;Hao Xing ,&nbsp;Qingping Li ,&nbsp;Yi Zhou ,&nbsp;Ziming Wang ,&nbsp;Lunxiang Zhang ,&nbsp;Pengfei Wang ,&nbsp;Jiafei Zhao ,&nbsp;Yongchen Song","doi":"10.1016/j.fuel.2025.135122","DOIUrl":"10.1016/j.fuel.2025.135122","url":null,"abstract":"<div><div>Carbon capture and storage (CCS) is a crucial strategy for mitigating global warming. The long-term sequestration of CO₂ by storing it as hydrates in marine sediments represents a potentially viable solution. Notably, most marine sediments exhibit a geothermal gradient, which significantly affects hydrates’ formation characteristics and spatial distribution. This study examines the impact of the geothermal gradient on CO₂ migration and sequestration, focusing on primary and secondary injections. More than 50 % of the reservoir’s water remains unutilized after the secondary injection, but the final gas conversion differs by 10 %. The findings indicate that gas diffusion is the primary factor influencing the formation of hydrates. Furthermore, gas transport mechanisms differ between primary and secondary injections under the geothermal gradient. During primary injection, the gas migrates through the sediment in a sequence comprising top accumulation, rapid diffusion, and top accumulation. During secondary injection, heat is cycled back and forth through the reservoir along with the phase transition of CO₂. A comparison of the primary and secondary injection processes revealed a stepwise distribution of hydrate formation, with the highest yield occurring in low-temperature zones and the lowest in high-temperature zones. These findings contribute to a more nuanced comprehension of CO₂ storage within marine sediments.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"394 ","pages":"Article 135122"},"PeriodicalIF":6.7,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flower-like nanoscale Ni(OH)2/MnCO3 electrocatalyst for efficient hydrogen evolution reaction in wide pH range","authors":"Zobia Siddique ,&nbsp;Salman Noshear Arshad ,&nbsp;Muhammad Ali Ehsan ,&nbsp;Faryal Aftab ,&nbsp;Akhtar Munir ,&nbsp;Suryyia Manzoor ,&nbsp;Sadia Fatima ,&nbsp;Farah Sajjad ,&nbsp;Javed Ahmad ,&nbsp;Hatice Duran ,&nbsp;Senem Çitoğlu","doi":"10.1016/j.fuel.2025.135164","DOIUrl":"10.1016/j.fuel.2025.135164","url":null,"abstract":"<div><div>It is indispensable to develop efficient and cost-effective electrocatalysts, especially those that can work in a wide pH range for the HER (hydrogen evolution reaction) and OER (oxygen evolution reaction). In this study, we have devised a hydrothermal one-pot method for the production of Ni(OH)₂/MnCO₃ composite nanosheets on nickel foam having close resemblance with flowers. The electrocatalyst exhibited appreciable performance for HER with a minimum overpotential of −60 m V and −120 mV in acidic and alkaline media respectively, to deliver 10 mA cm⁻² current density. Tafel slope of 38 mV dec^-1 (in acidic) and 112 mV dec^-1 (in alkaline) medium under a limited potential range of 0 to −0.1 V was observed. The significant performance of such a hybrid system can be attributed to thin sheet morphology, the mutual support of Ni(OH)₂ and Mn(CO₃)₂, and possible generation of active sites at the interface and may contribute to the electrochemically active surface area i.e. 350 cm² (acidic) 190 cm² (alkaline). This study presents a novel approach to pave the way for advanced self-supported nanoscale materials to boost HER in both acidic and alkaline environments.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"394 ","pages":"Article 135164"},"PeriodicalIF":6.7,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conversion of residual oil of ethylene tar into carbon precursors: Design, synthesis and mechanism exploration","authors":"Yuanqin Zhang ,&nbsp;Lingrui Cui ,&nbsp;Lian Cen ,&nbsp;Hengjian Pu ,&nbsp;Xingguo Wei ,&nbsp;Jian Huang ,&nbsp;Teng Zhai ,&nbsp;Jun Xu ,&nbsp;Fahai Cao","doi":"10.1016/j.fuel.2025.135108","DOIUrl":"10.1016/j.fuel.2025.135108","url":null,"abstract":"<div><div>To achieve full utilization of ethylene tar (ET), it is of imperative importance to convert its residual oil (RO) into high-valued materials. A novel strategy of RO utilization was developed by preparing condensed polynuclear aromatic (COPNA) resin using a tailor-designed novel crosslinking agent (4-<em>ter</em>-Butyl-2,6-bis(hydroxymethyl)phenol, TBBP) to react with RO, followed by the carbonization into high-valued carbon materials. RO was first thoroughly characterized to verify the feasibility as an excellent feedstock for resin preparation. A novel crosslinking agent, TBBP, was designed and synthesized to introduce oxygen-containing functional group into resins, intended to improve the electrochemical performance of the resulting resin-derived carbon. TBBP was demonstrated to possess enhanced electrophilic-substitution reactivity than 1,4-benzenedimethanol (PXG). It was then shown to be conducive to prepare resin from RO to yield TBBP-COPNA, with a maximum yield of 87.52 % and an oxygen content of 6.98 % under 1:1 (RO:TBBP), 180 ℃, 3 wt% catalyst dosage and 8 h. The carbon derived from TBBP-COPNA exhibited superior Na-storage performances to the one derived from PXG-COPNA, with a reversible capacity increased significantly from 122 to 250 mAh/g at 50 mA/g. Moreover, synthesis mechanism of TBBP-COPNA was explored through simulation. It was further revealed that the introduction of polar functional groups into resin was an effective method to improve electrochemical performance of resin-based carbon. The current strategy not only provided a high value-added utilization strategy for RO, but also developed a novel design and synthesis method of COPNA resin with polar functional group, thereby substantiating great potential to produce superior carbon anode for the Na-storage.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"394 ","pages":"Article 135108"},"PeriodicalIF":6.7,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intensifying the charge transfer on N–(CxNx+1) catalysts system: A cutting–edge approach for sunlight driven hydrogen production†","authors":"Ejaz Hussain ,&nbsp;Muhammad Jalil ,&nbsp;Javeria Mansab ,&nbsp;Muhammad Zeeshan Abid ,&nbsp;Shahid Iqbal ,&nbsp;Abeer Hashem ,&nbsp;Amal M. Al-Mohaimeed ,&nbsp;Elsayed Fathi Abd_Allah ,&nbsp;Khezina Rafiq","doi":"10.1016/j.fuel.2025.135113","DOIUrl":"10.1016/j.fuel.2025.135113","url":null,"abstract":"<div><div>Energy crises and global warming have become significant challenges for the developing countries, whereas competent authorities and policymakers ignore the urgency of implementing sustainable solutions, despite the serious nature of energy concerns. Additionally, both issues have been ignored rather than paying attention. I strongly believe, these can be resolved by the proper implementation of scientific and advanced technologies. On the other hand, atmosphere is consistently polluted due to extensive use of fossil fuels that are major contributor of global warming. To save the life on earth, green and carbon free atmosphere is necessary. This project has been designed to explore an alternative source in the form of hydrogen that potentially can produce from water (i.e. renewable source). For this purpose, nitrogen doped graphitic carbon nitride N–(C_xN_x+1) catalysts have been synthesized and assessed for hydrogen production. Catalysts have been prepared via melamine precursor, whereas nitrogen doping was achieved by the hydrothermal treatment. Morphology and optical characteristics have been assessed via XRD, FT–IR, Raman, UV–Vis–DRS, PL, TRPL, EIS, SEM and AFM analytical techniques. Purity, chemical compositions and electron transportation were confirmed by EDX, XPS, EIS and EPR studies. Catalytic reactions were performed in photoreactor (Velp–scientific), whereas hydrogen evolution activities were monitored with gas chromatography (GC–TCD Agilent/7890A). Results revealed that N–(C_xN_x+1) is more active catalyst that delivers almost 5 times more hydrogen (i.e. 16.39 mmol g^–¹ h^–¹) than pristine gC_xN_x+1 (3.25 mmol g^–¹ h^–¹). Results indicated that nitrogen dopants facilitate extra electrons on pi–conjugated system that make it more nucleophilic to readily react with H⁺ (electrophilic moieties). During the photoreaction, nucleophilic pi–conjugations of N–(C_xN_x+1) shift fermi energy levels to promote electron transfer on the active sites. On the basis of results and catalytic activities it has been concluded that ascribed catalysts have potential to replace the costly and conventional catalysts associated with hydrogen energy technologies.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"394 ","pages":"Article 135113"},"PeriodicalIF":6.7,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical looping of synthetic ilmenite. Part II: Multiscale perspective on modeling CLC and CLH","authors":"Steiner T. ,&nbsp;Schulze K. ,&nbsp;Anca-Couce A. ,&nbsp;Scharler R.","doi":"10.1016/j.fuel.2025.135040","DOIUrl":"10.1016/j.fuel.2025.135040","url":null,"abstract":"<div><div>This work investigates the chemical looping combustion (CLC) and chemical looping hydrogen (CLH) production processes of synthetic ilmenite at three relevant length scales: reactor, particle and reaction. Focusing on reduction with hydrogen, part I analyzed the reaction scale for CLC using thermogravimetric analysis (TGA). Complementary fixed bed reactor experiments for reduction and oxidation using pellets (CLC, CLH) and TGA experiments using powders or pellets (CLH) were now added. All measurements were used to develop a consistent multiscale model. Particle and reactor scales were described by one-dimensional volumetric models. The required complexity of the reaction model differed from case to case. Kinetic modeling for oxidations in the reactor was trivial, since gaseous reactants were fully consumed. Reductions with hydrogen, however, were more intricate. Considering the influence of equilibrium on the reactivity was crucial for CLH. The reduction for CLC was faster and even more complex. We novelly demonstrated how kinetics, originally derived only from TGA with powders, were not directly applicable to larger scales when underlying phenomena had been neglected. In order to overcome these limitations and achieve better consistency, equilibrium effects and the gas availability above the sample during TGA had to be considered. The suitability of the synthetic ilmenite for CLC and CLH was discussed based on the findings in this work.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"394 ","pages":"Article 135040"},"PeriodicalIF":6.7,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In situ fabrication of defect-rich MoS2-x onto consecutive nanofibers to construct proton exchange membrane with enhanced direct methanol fuel cell performance","authors":"Li Xia ,&nbsp;Zhiyong Zeng ,&nbsp;Ke Li ,&nbsp;Chuanjing Cheng ,&nbsp;Shenglan Xu ,&nbsp;Jie Wang ,&nbsp;Fei Zhong ,&nbsp;Nannan Yang ,&nbsp;Chuang Xu ,&nbsp;Wenjuan Niu ,&nbsp;Yu Ding","doi":"10.1016/j.fuel.2025.135123","DOIUrl":"10.1016/j.fuel.2025.135123","url":null,"abstract":"<div><div>It remains highly challenging to construct proton exchange membranes (PEMs) with high proton conductivity and low methanol permeability, as both proton and methanol are mainly transported through the hydrophilic region of PEMs. Here, we first designed novel ultrathin two-dimensional molybdenum disulfide nanosheets rich in sulfur vacancy defects anchored onto bacterial cellulose nanofiber surface (BC@MoS_2-x) via a one-step hydrothermal method, which were then embedded in sulfonated poly (ether ether ketone) (SPEEK) matrix to obtain high-performance composite PEMs (SPEEK/BC@MoS_2-x) with a consecutive and orderly arrangement of MoS_2-x. SPEEK/BC@MoS_2-x exhibited a proton conductivity of 0.132 S cm⁻¹ (80 °C, 100 % RH) and methanol permeability of 31.15 × 10^-7 cm² s⁻¹. Such superior performance can be attributed to the interconnected hydrophilic BC@MoS_2-x nanofiber structure, which provides consecutive proton transfer channels to allow easy proton transfer through the hydration channels, as well as a 3D nanofiber network structure to result in more tortuous penetration of methanol. In addition, the robust and continuous nanofiber network of BC@MoS_2-x can support the composite membrane to promote the thermal dimensional stability and mechanical properties. Overall, this study provides a novel method for the preparation of high-performance PEMs for direct methanol fuel cells.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"394 ","pages":"Article 135123"},"PeriodicalIF":6.7,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flame behaviors, pressure evolution, and molecular reaction mechanism of methane/pulverized bituminous coal hybrid deflagrations","authors":"Yihao Yao ,&nbsp;Haitao Li ,&nbsp;Jiachen Wang ,&nbsp;Jie Li ,&nbsp;Minggao Yu","doi":"10.1016/j.fuel.2025.135157","DOIUrl":"10.1016/j.fuel.2025.135157","url":null,"abstract":"<div><div>The deflagration of methane/powdered coal hybrids poses a serious risk to the production safety and personnel health for underground coal mines. In this study, we firstly performed 21 sets of deflagration experiments to investigate the pressure variation and flame behaviors of methane/pulverized bituminous coal mixtures. The experimental results revealed that the explosive power attains its maximum at 9.5 vol% methane and 100 g/m³ of pulverized coal, whereas the maximum flame propagation speed was recorded at 35.08 m/s with 9.5 vol% methane and 50 g/m³ of pulverized coal. The gas-phase reaction predominantly governs the deflagration characteristics of the mixtures, with methane concentration significantly exerting a more significant influence on these characteristics than powdered coal concentration. Then, reactive field molecular dynamics (ReaxFF-MD) simulations were conducted to explore the microscopic mechanism of methane/pulverized bituminous coal hybrid deflagrations. The simulation results indicated that bituminous coal molecules undergo successive repeated pyrolysis, generating a substantial number of active intermediates and gaseous products. These volatile species contribute to the gas-phase deflagration reaction, thereby intensifying the overall deflagration process. The primary pathway of the gas-phase deflagration reaction involves the following radical reactions: CH₄ → <strong>·</strong>CH₃ → <strong>·</strong>CH₃O → CH₂O → <strong>·</strong>CHO → CO+H₂ → CO₂+H₂O. This study would provide scientific guidance for efficient prediction, control, and reduction of methane/pulverized bituminous coal hybrid deflagration accidents.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"394 ","pages":"Article 135157"},"PeriodicalIF":6.7,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preparation and utilization of biodiesel-water emulsions in compression ignition engines − A critical review","authors":"G. Sudarshan ,&nbsp;R. Preetika ,&nbsp;Anand Krishnasamy ,&nbsp;M.G. Basavaraja ,&nbsp;S.A. Indrapal","doi":"10.1016/j.fuel.2025.135124","DOIUrl":"10.1016/j.fuel.2025.135124","url":null,"abstract":"<div><div>Conventional diesel combustion (CDC) predominantly involves mixing-controlled combustion that encounters high-temperature regimes with high equivalence ratios, resulting in the formation of oxides of nitrogen (NO_x) and particulate matter (PM) emissions, respectively. The concurrent abatement of these pollutants is challenging for the CDC owing to distinct dissimilarities in their formation mechanisms, leading to the common NO_x-PM trade-off. Significant research efforts are made on in-cylinder emission control using fuel modification-driven methodologies because of their potential to curtail NO_x and PM levels. In the automotive sector, diesel can be replaced with biodiesel owing to its carbon–neutral nature and mimicking diesel-like properties. Additionally, the NO_x-PM trade-off in CDC is altered as a higher NO_x challenge with biodiesel. Due to better engine performance and emission reduction advantages, water emulsions with diesel–biodiesel blend and neat biodiesel have garnered considerable attention as a diesel alternative. The literature has reported a 40% reduction in NO_x and smoke emission values with emulsions compared to biodiesel. Such results were observed with tests conducted on a single-cylinder diesel engine operated by a conventional mechanical fuel injection system. The results for HC and CO emissions vary, with a few studies reporting a near 20% decrease in both, while others have observed up to 35% increase in these emissions. Although the brake thermal efficiency and specific fuel consumption results also vary, commonly observed results include up to 3 to 5% improvement in either of these parameters. Unfortunately, adequate analysis of emulsion fuels’ formation and stability before utilizing them in compression ignition engines remains largely unexplored. The impact of emulsion fuels on engine performance and emission is based on the composition of the emulsion, its microstructure, the type of engine, and the prevailing operating conditions. Most investigations on engine characteristics do not present detailed information on the emulsion characterization. The present review highlights the significance of the stability study of emulsion fuels relevant to compression ignition engine applications. The current state-of-the-art biodiesel-water emulsion formulation, characterization, macroscopic spray characteristics, effects on performance, and emission parameters in conventional and advanced alternate combustion conditions are discussed. The review concludes by providing suggestions for emulsion fuel sustainability and exploring novel alternative surfactants to prepare stable biodiesel-water emulsions.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"394 ","pages":"Article 135124"},"PeriodicalIF":6.7,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular simulation of CO2 foam injection to reduce water lock effect and enhance CH4 replacement in coal","authors":"Bingnan Ji,&nbsp;Hongyu Pan,&nbsp;Yuxuan Zhou,&nbsp;Mingyue Pan,&nbsp;Xiang Ji,&nbsp;Hongjiao Chen,&nbsp;Ziyu Zhu,&nbsp;Tianjun,&nbsp;Zhang","doi":"10.1016/j.fuel.2025.135118","DOIUrl":"10.1016/j.fuel.2025.135118","url":null,"abstract":"<div><div>CO₂ foam fracturing technology has gradually been utilized to fracture coalbed methane (CBM) wells over recent years with the advantages of low water consumption, high fracturing fluid return rate and the ability to displace CH₄ in the coal reservoir. To explore the CH₄ desorption mechanism affected by CO₂ foam fracturing fluid injection into coal seam, the interaction microscopic mechanism between CH₄/CO₂/H₂O as well as interaction with coal molecules was examined employing density functional theory (DFT). By injecting varying quality of CO₂ foam (0% pure water, 20%, 40%, 60%, and 80%) into coal containing CH₄, the water lock formation and the replacement and diffusion of CH₄ following CO₂ foam injection into coal were examined. The findings indicate that hydrogen bond facilitates the formation of H₂O clusters, which attract CO₂ and repel CH₄. The greater adsorption and coexistence of CO₂ and H₂O encourage them to occupy adsorption sites on coal molecules and replace CH₄. As the foam quality increased, the H₂O cluster volume in the slit pores and the water film effect decreased, consequently weakening the water lock effect. The effect of CO₂ and H₂O co-adsorption on the coal matrix surface to replace adsorbed CH₄ was gradually enhanced. The co-adsorption system for CO₂/H₂O with coal matrix was more stable after the injection of higher-quality CO₂ foam, facilitating CH₄ desorption. The CO₂ adsorption depth within the coal matrix exceeded that of H₂O, which could further replace adsorbed CH₄. The diffusivity of adsorbed and free H₂O was predominantly affected by clusters and hydrogen bonds. The diffusion coefficients of adsorbed CO₂ and free CH₄ and CO₂ declined with enhanced CO₂ foam quality, while the diffusion coefficient of adsorbed CH₄ initially rose and then decreased. The research findings furnished a theoretical basis for CO₂ foam to replace CH₄ in coal seams to enhance the CBM recovery (CO₂ foam-ECBM).</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"394 ","pages":"Article 135118"},"PeriodicalIF":6.7,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}