Pub Date : 2025-02-21DOI: 10.1016/j.fuel.2025.134800
Lu Wang , Chuhao Wang , Yuhe Mu , Jingrui Fan , Xiubei Yang , Chengbing Yu , Bing Guo , Gaofeng Zeng
This study reports on the fabrication and characterization of nanofibrous high-entropy alloy (HEA)-based electrocatalysts supported by highly mesoporous carbon materials for efficient alkaline water electrolysis. Employing a synergistic approach of electrospinning, activation, and carbonization, we have developed a material with a high specific surface area and unique structural features that significantly enhance catalytic activity. The FeCoNiMnRu-HCB0.5 electrode material showcased superior electrocatalytic performance for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), with low overpotentials of 42 mV for HER and 229 mV for OER at a current density of 10 mA cm−2. These values are notably lower than those of commercial noble metal catalysts. The electrode material demonstrated excellent stability over prolonged periods of electrolysis, indicating its potential for practical applications in energy storage and conversion technologies. Our results suggest that this HEA-based electrocatalyst is a promising candidate for next-generation electrocatalytic materials, offering high efficiency and durability for water splitting in alkaline media.
{"title":"Mesoporous high-entropy-alloy electrocatalysts via electrospinning for enhanced alkaline water electrolysis","authors":"Lu Wang , Chuhao Wang , Yuhe Mu , Jingrui Fan , Xiubei Yang , Chengbing Yu , Bing Guo , Gaofeng Zeng","doi":"10.1016/j.fuel.2025.134800","DOIUrl":"10.1016/j.fuel.2025.134800","url":null,"abstract":"<div><div>This study reports on the fabrication and characterization of nanofibrous high-entropy alloy (HEA)-based electrocatalysts supported by highly mesoporous carbon materials for efficient alkaline water electrolysis. Employing a synergistic approach of electrospinning, activation, and carbonization, we have developed a material with a high specific surface area and unique structural features that significantly enhance catalytic activity. The FeCoNiMnRu-HCB<sub>0.5</sub> electrode material showcased superior electrocatalytic performance for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), with low overpotentials of 42 mV for HER and 229 mV for OER at a current density of 10 mA cm<sup>−2</sup>. These values are notably lower than those of commercial noble metal catalysts. The electrode material demonstrated excellent stability over prolonged periods of electrolysis, indicating its potential for practical applications in energy storage and conversion technologies. Our results suggest that this HEA-based electrocatalyst is a promising candidate for next-generation electrocatalytic materials, offering high efficiency and durability for water splitting in alkaline media.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"391 ","pages":"Article 134800"},"PeriodicalIF":6.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452884","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}
Pub Date : 2025-02-21DOI: 10.1016/j.fuel.2025.134773
Jianhang Li , Wenkai Liang , Wenhu Han , Chung K. Law
In this study, we computationally investigated the explosion limits of hydrogen–oxygen (H2-O2) mixtures with a catalytic platinum (Pt) surface. As a classical problem in combustion kinetics, the explosion limits of H2-O2 mixtures show the non-monotonic, Z-shaped response. Current results show that the explosion limits over Pt still retain the Z-shaped response, but become more explosive. The transition is explained by the responses of the kinetic parameters describing the gaseous and catalytic reactions competition. For the surface species, hydrogen oxidation is characterized mainly by the desorption of H(S) from the surface to allow the numbers of Pt(S), O(S), OH(S), and H2O(S) sites to increase. Results further show that the site density, residence time, catalytic area, and reactor volume show different effects on the explosion limits. The more intriguing result is that, with increasing equivalence ratio, the H2-O2 explosion limit curve in the pressure–temperature space rotates counterclockwise around a point on the third limit, which is determined by the different reactivities of gaseous and catalytic reactions for low- and high-pressure conditions. In addition, catalytic and wall termination effects on the limits are compared. The result provides useful insights into the surface reaction kinetics of the H2-O2 explosion limits over Pt, which is closely related to the efficient utilization as well as the assessment of safety issues for hydrogen.
{"title":"On explosion limits of hydrogen–oxygen mixtures with a catalytic platinum surface","authors":"Jianhang Li , Wenkai Liang , Wenhu Han , Chung K. Law","doi":"10.1016/j.fuel.2025.134773","DOIUrl":"10.1016/j.fuel.2025.134773","url":null,"abstract":"<div><div>In this study, we computationally investigated the explosion limits of hydrogen–oxygen (H<sub>2</sub>-O<sub>2</sub>) mixtures with a catalytic platinum (Pt) surface. As a classical problem in combustion kinetics, the explosion limits of H<sub>2</sub>-O<sub>2</sub> mixtures show the non-monotonic, Z-shaped response. Current results show that the explosion limits over Pt still retain the Z-shaped response, but become more explosive. The transition is explained by the responses of the kinetic parameters describing the gaseous and catalytic reactions competition. For the surface species, hydrogen oxidation is characterized mainly by the desorption of H(S) from the surface to allow the numbers of Pt(S), O(S), OH(S), and H<sub>2</sub>O(S) sites to increase. Results further show that the site density, residence time, catalytic area, and reactor volume show different effects on the explosion limits. The more intriguing result is that, with increasing equivalence ratio, the H<sub>2</sub>-O<sub>2</sub> explosion limit curve in the pressure–temperature space rotates counterclockwise around a point on the third limit, which is determined by the different reactivities of gaseous and catalytic reactions for low- and high-pressure conditions. In addition, catalytic and wall termination effects on the limits are compared. The result provides useful insights into the surface reaction kinetics of the H<sub>2</sub>-O<sub>2</sub> explosion limits over Pt, which is closely related to the efficient utilization as well as the assessment of safety issues for hydrogen.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"391 ","pages":"Article 134773"},"PeriodicalIF":6.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452888","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}
Pub Date : 2025-02-21DOI: 10.1016/j.fuel.2025.134778
Yanming Zhong , Xiaoying Su , Zongsun Zhang , Yi Zheng , Ying Zhou , Yunqin Lin
Energy input for substrate stirring is generally demanded in dry anaerobic digestion. Semi-continuous dry anaerobic digestion of rice straw pretreated with swine manure digested effluent (named as ammoniated rice straw) in a vertical cascade digester with varied solid contents (20 %, 25 %, and 30 %) was investigated for energy and room saving. The analysis of sCOD, VFA, ALK, and TAN which refer to the stability of anaeobic digestion showed that the digestion in the TS = 25 % system was the stablest, while the acidogenesis decreased on days 120–180 in the TS = 20 % digester, and the hydrolysis and acidogenesis both decreased on days 120–180 in the TS = 30 % digester. The correlation analyses of sCOD, VFA, ALK, and TAN showed a positive correlation between factors in the TS = 25 % digester which was favourable for a long-term operation, while negative or weak positive correlations between the above factors in the digesters of TS = 20 % and TS = 30 % were noted. Moreover, the average daily methane yield in the digesters ranged from 1.69 to 2.15 mL/gVSadded, among which the average daily methane yields in the digesters of TS = 20 % and TS = 25 % were 27.21 % and 24.85 % higher than that in the TS = 30 % digester, respectively. The results indicated that a semi-continuous stable biogas production from rice straw-swine manure digestate could be achieved at a 25 % solid content in a vertical cascade anaerobic digester (SVCAD). Also, the microbial community structure analysis in the TS = 20 % digester revealed a decrease in community diversity in the course of digestion time. Bacteroidota became the dominant bacteria (exceeding 50 % in relative abundance) in stage II at the phylum level, and DMER64 and LNR A2-18 became the predominant genera at the genus level. This work firstly reported the anaerobic digestion of ammoniated rice straw in a SVCAD, and drew a conclusion on the appropriate total solid for the long-term running in a SVCAD. It is a contribution for the development of efficient biofuel production from piggery waste and crop residues.
{"title":"Semi-continuous dry anaerobic digestion of rice straw pretreated with swine manure digested effluent in one vertical cascade digester with different solid contents","authors":"Yanming Zhong , Xiaoying Su , Zongsun Zhang , Yi Zheng , Ying Zhou , Yunqin Lin","doi":"10.1016/j.fuel.2025.134778","DOIUrl":"10.1016/j.fuel.2025.134778","url":null,"abstract":"<div><div>Energy input for substrate stirring is generally demanded in dry anaerobic digestion. Semi-continuous dry anaerobic digestion of rice straw pretreated with swine manure digested effluent (named as ammoniated rice straw) in a vertical cascade digester with varied solid contents (20 %, 25 %, and 30 %) was investigated for energy and room saving. The analysis of sCOD, VFA, ALK, and TAN which refer to the stability of anaeobic digestion showed that the digestion in the TS = 25 % system was the stablest, while the acidogenesis decreased on days 120–180 in the TS = 20 % digester, and the hydrolysis and acidogenesis both decreased on days 120–180 in the TS = 30 % digester. The correlation analyses of sCOD, VFA, ALK, and TAN showed a positive correlation between factors in the TS = 25 % digester which was favourable for a long-term operation, while negative or weak positive correlations between the above factors in the digesters of TS = 20 % and TS = 30 % were noted. Moreover, the average daily methane yield in the digesters ranged from 1.69 to 2.15 mL/gVS<sub>added</sub>, among which the average daily methane yields in the digesters of TS = 20 % and TS = 25 % were 27.21 % and 24.85 % higher than that in the TS = 30 % digester, respectively. The results indicated that a semi-continuous stable biogas production from rice straw-swine manure digestate could be achieved at a 25 % solid content in a vertical cascade anaerobic digester (SVCAD). Also, the microbial community structure analysis in the TS = 20 % digester revealed a decrease in community diversity in the course of digestion time. <em>Bacteroidota</em> became the dominant bacteria (exceeding 50 % in relative abundance) in stage II at the phylum level, and <em>DMER64</em> and <em>LNR A2-18</em> became the predominant genera at the genus level. This work firstly reported the anaerobic digestion of ammoniated rice straw in a SVCAD, and drew a conclusion on the appropriate total solid for the long-term running in a SVCAD. It is a contribution for the development of efficient biofuel production from piggery waste and crop residues.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"391 ","pages":"Article 134778"},"PeriodicalIF":6.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452737","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}
Pub Date : 2025-02-21DOI: 10.1016/j.fuel.2025.134732
Ardhika Setiawan , Ocktaeck Lim
The experimental and numerical study was conducted to evaluate the effects of the propane ratio and diesel on the emissions and combustion characteristics of propane applied on LPG direct injection (LPG-Di) engines. The experiment was conducted on a rapid compression expansion machine (RCEM) that was modified to satisfy the dual direct injection fuel (diesel-propane) – compression ignition (CI) strategy. Compression ratio (CR) 19 was used for the experiment with the propane energy fraction 10 % to 100 %. To find the optimum auto-ignition characteristics of propane, the start of injection (SOI) of propane was varied from 0° to 40° before top dead center (BTDC). While the SOI of diesel was maintained at 10° BTDC for the auto-ignition assistance purpose. The detailed emission propagation during the combustion process was constructed using computational fluid dynamic (CFD) modeling. Propane exhibits a second stage of combustion during the expansion step, indicating that the fuel cannot be burned perfectly during the initial auto-ignition process. The application of propane up to 50 % on direct injection CI engines shows the indication of CO2, HC, and NOx emission increase. Applying SOI to propane at 0 and 40 BTDC on propane energy fraction of more than 50 % % reveals a considerable variation in emissions, indicating low combustion quality that enhances emission formation.
{"title":"An investigation of the effect of propane energy fraction and the start of injection on the emissions characteristics on low carbon high-pressure LPG direct injection engine","authors":"Ardhika Setiawan , Ocktaeck Lim","doi":"10.1016/j.fuel.2025.134732","DOIUrl":"10.1016/j.fuel.2025.134732","url":null,"abstract":"<div><div>The experimental and numerical study was conducted to evaluate the effects of the propane ratio and diesel on the emissions and combustion characteristics of propane applied on LPG direct injection (LPG-Di) engines. The experiment was conducted on a rapid compression expansion machine (RCEM) that was modified to satisfy the dual direct injection fuel (diesel-propane) – compression ignition (CI) strategy. Compression ratio (CR) 19 was used for the experiment with the propane energy fraction 10 % to 100 %. To find the optimum auto-ignition characteristics of propane, the start of injection (SOI) of propane was varied from 0° to 40° before top dead center (BTDC). While the SOI of diesel was maintained at 10° BTDC for the auto-ignition assistance purpose. The detailed emission propagation during the combustion process was constructed using computational fluid dynamic (CFD) modeling. Propane exhibits a second stage of combustion during the expansion step, indicating that the fuel cannot be burned perfectly during the initial auto-ignition process. The application of propane up to 50 % on direct injection CI engines shows the indication of CO2, HC, and NOx emission increase. Applying SOI to propane at 0 and 40 BTDC on propane energy fraction of more than 50 % % reveals a considerable variation in emissions, indicating low combustion quality that enhances emission formation.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"391 ","pages":"Article 134732"},"PeriodicalIF":6.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452889","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}
Pub Date : 2025-02-21DOI: 10.1016/j.fuel.2025.134803
Guang-Hui Liu , Hao-Dong An , Han Wang , Ya-Jun Ma , Yan-Jun Li , Yu-Hong Kang , Jie Kang , Wei Zhao , Sheng-Kang Wang , Xian-Yong Wei
A novel ZIF-67-based Co-Mo bimetallic synergistic catalyst was prepared via Mo/N co-doping in-situ pyrolysis strategy and used in the cascade conversion system of hydrocracking (H2 activation) and ethanolysis (solvent activation) of Dongming lignite. Co-Mo15@NC, rich in vacancies/defects, can differentially activate H2 and ethanol, promoting the selective conversion of lignite-derived aryl ethers into high-yield arenes or aromatic monomers. Comprehensive evaluation indicates that this catalyst exhibits excellent > C-O- cleavage activity and cyclic stability, and is easy to magnetic recovery. Analysis of intermediates and products shows that hydrocracking system involves the synergistic transfer of H+, H·, and asymmetric diatomic active hydrogen (δ+H···Hδ-), while ethanolysis system involves the synergistic transfer of H+, H·, C2H5+, and C2H5O·. Hydrocracking-derived oil (SP1C) from first-stage is rich in alkanes and polycyclic arenes, with the total content of hydrocarbons increasing from 67.7 to 78.1 %, while ethanolysis-derived oil (SP2C) from second-stage is rich in alkanols, arenols, and esters, with the total content of O-containing compounds increasing from 66.7 to 90.3 %. Two types of value-added oils, i.e., hydrocarbon-rich and O-rich oils, can be obtained by the two-step cascade degradation strategy based on H2 and ethanol activation.
{"title":"Two-step cascade degradation of Dongming lignite over Mo/N co-doped ZIF-67-based Co-Mo15@NC","authors":"Guang-Hui Liu , Hao-Dong An , Han Wang , Ya-Jun Ma , Yan-Jun Li , Yu-Hong Kang , Jie Kang , Wei Zhao , Sheng-Kang Wang , Xian-Yong Wei","doi":"10.1016/j.fuel.2025.134803","DOIUrl":"10.1016/j.fuel.2025.134803","url":null,"abstract":"<div><div>A novel ZIF-67-based Co-Mo bimetallic synergistic catalyst was prepared <em>via</em> Mo/N co-doping <em>in-situ</em> pyrolysis strategy and used in the cascade conversion system of hydrocracking (H<sub>2</sub> activation) and ethanolysis (solvent activation) of Dongming lignite. Co-Mo<sub>15</sub>@NC, rich in vacancies/defects, can differentially activate H<sub>2</sub> and ethanol, promoting the selective conversion of lignite-derived aryl ethers into high-yield arenes or aromatic monomers. Comprehensive evaluation indicates that this catalyst exhibits excellent > C-O- cleavage activity and cyclic stability, and is easy to magnetic recovery. Analysis of intermediates and products shows that hydrocracking system involves the synergistic transfer of H<sup>+</sup>, H<strong>·</strong>, and asymmetric diatomic active hydrogen (<sup>δ+</sup>H<strong>···</strong>H<sup>δ-</sup>), while ethanolysis system involves the synergistic transfer of H<sup>+</sup>, H<strong>·</strong>, C<sub>2</sub>H<sub>5</sub><sup>+</sup>, and C<sub>2</sub>H<sub>5</sub>O<strong>·</strong>. Hydrocracking-derived oil (SP<sub>1C</sub>) from first-stage is rich in alkanes and polycyclic arenes, with the total content of hydrocarbons increasing from 67.7 to 78.1 %, while ethanolysis-derived oil (SP<sub>2C</sub>) from second-stage is rich in alkanols, arenols, and esters, with the total content of O-containing compounds increasing from 66.7 to 90.3 %. Two types of value-added oils, <em>i.e.</em>, hydrocarbon-rich and O-rich oils, can be obtained by the two-step cascade degradation strategy based on H<sub>2</sub> and ethanol activation.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"391 ","pages":"Article 134803"},"PeriodicalIF":6.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452736","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}
Pub Date : 2025-02-20DOI: 10.1016/j.fuel.2025.134776
Kexin Chen , Pengfei Liu , Wenyuan Wang , Linhan Wang , Yan Wang , Hao Liu , Zizhuang Yan , Yu Zhao , Kaichen Song , Yunmin Chen , Bate Bate
Hypergravity offers transformative potential for enhanced oil recovery (EOR) and CO2 sequestration by mimicking subsurface geostress and pressure conditions, facilitating the study of large-scale physical phenomena like fluid migration and sediment compaction within reduced experimental timeframes and scales. In CO2 sequestration, hypergravity shortens Ostwald ripening, facilitates bubble coalescence, and intensifies gas–solid mass transfer. While the dynamic process of two-phase flow under hypergravity remains insufficiently explored. Hence, a hypergravity microfluidic observation system (HMOS) was developed to investigate the aforementioned process. Seven sets of water–oil displacement experiments were conducted on two chips (channel depths of 160 μm and 30 μm) under 0 g, 1 g, and 50 g conditions, with capillary numbers (Ca) ranging from 9.55 × 10-6 to 9.05 × 10-5 (typical of the viscous fingering regime) and Bond numbers (Bo) ranging from −0.69 to 0. The results demonstrate that hypergravity (50 g) dragged down the bulk of the dense defending phase, reducing the local pressure gradient at the fluid–fluid interface, and thereby inhibited the upward advancement of the invading phase. In a wide flow channel (576 μm in Chip 1, Bo = -0.69), hypergravity overwhelmed viscous forces, accelerated the dense defending phase downward, even pinched off the invading phase (snap-off), and thus reduced displacement efficiency (Snw) to 26.9 % (compared to 55.5 % at 1 g); while in a narrow flow channel (80 μm in Chip 2, Bo = -0.0133), the effects of hypergravity and viscous forces were comparable, resulting in enhanced lateral spreading of the invading phase, and thus drastically improved Snw up to 60.9 % (compared to 29.6 % at 1 g). Meanwhile, hypergravity has a secondary influence on the displacement morphology, as evidenced by the fact that the slope of fluid–fluid interface length (lnw) to invading phase saturation (Snw) were constricted to narrow ranges (23.04 ∼ 29.12 for Chip 1, and 50.46 ∼ 64.96 for Chip 2). These findings shed lights on the immiscible fluid–fluid displacement efficiency and morphology under hypergravity, providing insights on applying hypergravity field on meter level models to simulate large-scale and long-duration physical phenomena encountered in deep-earth oil recovery.
{"title":"Hypergravity experimental study on immiscible fluid–fluid displacement in micromodels","authors":"Kexin Chen , Pengfei Liu , Wenyuan Wang , Linhan Wang , Yan Wang , Hao Liu , Zizhuang Yan , Yu Zhao , Kaichen Song , Yunmin Chen , Bate Bate","doi":"10.1016/j.fuel.2025.134776","DOIUrl":"10.1016/j.fuel.2025.134776","url":null,"abstract":"<div><div>Hypergravity offers transformative potential for enhanced oil recovery (EOR) and CO<sub>2</sub> sequestration by mimicking subsurface geostress and pressure conditions, facilitating the study of large-scale physical phenomena like fluid migration and sediment compaction within reduced experimental timeframes and scales. In CO<sub>2</sub> sequestration, hypergravity shortens Ostwald ripening, facilitates bubble coalescence, and intensifies gas–solid mass transfer. While the dynamic process of two-phase flow under hypergravity remains insufficiently explored. Hence, a hypergravity microfluidic observation system (HMOS) was developed to investigate the aforementioned process. Seven sets of water–oil displacement experiments were conducted on two chips (channel depths of 160 μm and 30 μm) under 0 g, 1 g, and 50 g conditions, with capillary numbers (<em>Ca</em>) ranging from <em>9.55 × 10<sup>-6</sup></em> to <em>9.05 × 10<sup>-5</sup></em> (typical of the viscous fingering regime) and Bond numbers (<em>Bo</em>) ranging from <em>−0.69</em> to <em>0</em>. The results demonstrate that hypergravity (50 g) dragged down the bulk of the dense defending phase, reducing the local pressure gradient at the fluid–fluid interface, and thereby inhibited the upward advancement of the invading phase. In a wide flow channel (576 μm in Chip 1, <em>Bo</em> = -0.69), hypergravity overwhelmed viscous forces, accelerated the dense defending phase downward, even pinched off the invading phase (snap-off), and thus reduced displacement efficiency (<em>S<sub>nw</sub></em>) to 26.9 % (compared to 55.5 % at 1 g); while in a narrow flow channel (80 μm in Chip 2, <em>Bo</em> = -0.0133), the effects of hypergravity and viscous forces were comparable, resulting in enhanced lateral spreading of the invading phase, and thus drastically improved <em>S<sub>nw</sub></em> up to 60.9 % (compared to 29.6 % at 1 g). Meanwhile, hypergravity has a secondary influence on the displacement morphology, as evidenced by the fact that the slope of fluid–fluid interface length (<em>l<sub>nw</sub></em>) to invading phase saturation (<em>S<sub>nw</sub></em>) were constricted to narrow ranges (23.04 ∼ 29.12 for Chip 1, and 50.46 ∼ 64.96 for Chip 2). These findings shed lights on the immiscible fluid–fluid displacement efficiency and morphology under hypergravity, providing insights on applying hypergravity field on meter level models to simulate large-scale and long-duration physical phenomena encountered in deep-earth oil recovery.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"391 ","pages":"Article 134776"},"PeriodicalIF":6.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452770","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}
Pub Date : 2025-02-20DOI: 10.1016/j.fuel.2025.134768
Shilpa Kulbhushan Nandwani , Krishna Kanta Das , Bishnu Medhi , Dipankar Dutta , Mousumi Chakraborty
In recent years, there is a surge of interest in harnessing nanoparticles for enhancing mass transfer of CO2 in water. Utilizing Nickel nanoparticles for enhancing CO2 solubility in brine and preparing carbonated water for the purpose of addition oil recovery and CO2 storage, has not been reported to date.
Nickel nanoparticles settle down easily when dispersed in brine containing monovalent and/or divalent ions. In this study, prior to absorbing CO2 in brine, stable nickel-nanosuspensions in brine have been prepared, by adding a bio-polymer, Xanthan Gum as a stabilizer. Addition of Xanthan gum (XG) escalates brine viscosity, thereby reducing the sedimentation rate of Nickel nanoparticle decreases. It has been observed that, at room temperature, stable NiNP-XG-brine nanosuspension can be prepared at XG concentration greater than or equal to 0.2 wt%. Various factors such as temperature, concentration of Xanthan Gum and Nickel nanoparticles, that effect the viscosity and stability of Nickel nanosuspensions prepared in XG-brine mixture have been studied. Characterization techniques such as zeta potential analysis, turbiscan stability analysis, measuring dynamic viscosity and visual observations have been used for this purpose.
In this study, pressure-decay-based method is proposed to calculate molal solubility, Henry’s constant, and diffusivity of CO2 in deionized water, synthetic brine, and the prepared nickel nanofluids at initial pressure of 50 bar and temperature of 32 ℃. Thereafter, the pressure–time data collected after each experiment and an analytical-graphical approach suggested by Pacheo-Roman and Hejazi is used to solve Fick’s second law equation of diffusion that governs the diffusion process. The results provide new insight into the mechanisms of CO2 mass transfer in the nickel nanofluids. It is found that molal solubility of CO2 in NiNP-XG-brine nanosuspension containing 0.2 wt% XG is greater than brine. Moreover, solubility of CO2 in NiNP-XG-brine nanosuspension containing 0.02 wt% NiNP and 0.2 wt% XG is 15 % more than pure brine. The observed increase might be attributed to enhanced hydration of CO2 in presence of Nickel nanoparticles. However, it is observed that diffusivity of CO2 in deionized water and brine are greater than all the NiNP-XG-brine nanosuspension studied here.
{"title":"Preparation of stable nickel nanosuspensions and evaluation of their efficiency in enhancing carbondioxide solubility in brine","authors":"Shilpa Kulbhushan Nandwani , Krishna Kanta Das , Bishnu Medhi , Dipankar Dutta , Mousumi Chakraborty","doi":"10.1016/j.fuel.2025.134768","DOIUrl":"10.1016/j.fuel.2025.134768","url":null,"abstract":"<div><div>In recent years, there is a surge of interest in harnessing nanoparticles for enhancing mass transfer of CO<sub>2</sub> in water. Utilizing Nickel nanoparticles for enhancing CO<sub>2</sub> solubility in brine and preparing carbonated water for the purpose of addition oil recovery and CO<sub>2</sub> storage, has not been reported to date.</div><div>Nickel nanoparticles settle down easily when dispersed in brine containing monovalent and/or divalent ions. In this study, prior to absorbing CO<sub>2</sub> in brine, stable nickel-nanosuspensions in brine have been prepared, by adding a bio-polymer, Xanthan Gum as a stabilizer. Addition of Xanthan gum (XG) escalates brine viscosity, thereby reducing the sedimentation rate of Nickel nanoparticle decreases. It has been observed that, at room temperature, stable NiNP-XG-brine nanosuspension can be prepared at XG concentration greater than or equal to 0.2 wt%. Various factors such as temperature, concentration of Xanthan Gum and Nickel nanoparticles, that effect the viscosity and stability of Nickel nanosuspensions prepared in XG-brine mixture have been studied. Characterization techniques such as zeta potential analysis, turbiscan stability analysis, measuring dynamic viscosity and visual observations have been used for this purpose.</div><div>In this study, pressure-decay-based method is proposed to calculate molal solubility, Henry’s constant, and diffusivity of CO<sub>2</sub> in deionized water, synthetic brine, and the prepared nickel nanofluids at initial pressure of 50 bar and temperature of 32 ℃. Thereafter, the pressure–time data collected after each experiment and an analytical-graphical approach suggested by Pacheo-Roman and Hejazi is used to solve Fick’s second law equation of diffusion that governs the diffusion process. The results provide new insight into the mechanisms of CO<sub>2</sub> mass transfer in the nickel nanofluids. It is found that molal solubility of CO<sub>2</sub> in NiNP-XG-brine nanosuspension containing 0.2 wt% XG is greater than brine. Moreover, solubility of CO<sub>2</sub> in NiNP-XG-brine nanosuspension containing 0.02 wt% NiNP and 0.2 wt% XG is 15 % more than pure brine. The observed increase might be attributed to enhanced hydration of CO<sub>2</sub> in presence of Nickel nanoparticles. However, it is observed that diffusivity of CO<sub>2</sub> in deionized water and brine are greater than all the NiNP-XG-brine nanosuspension studied here.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"390 ","pages":"Article 134768"},"PeriodicalIF":6.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143444964","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}
Pub Date : 2025-02-20DOI: 10.1016/j.fuel.2025.134610
Guangyao Yang, Aiwu Fan
There exist urgent demands for miniature combustion-based power devices due to their high energy densities. We recently integrated a T-shaped porous zone into a meso-scale combustor with an inner radius (R) of 3 mm. Numerical simulation demonstrated that this new configuration harvested a maximum flame blow-off limit of 1.05 m/s for stoichiometric C4H10/air mixtures, which is almost twice of the counterpart (0.55 m/s) of original combustor with cylindrical porous media. In the present study, further optimization of this combustor was performed by varying the protruding part radius (r) of the T-shaped porous zone. The findings indicate that as r rises from 0.5 to 2.0 mm, flame blow-off limit keeps increasing to 1.65 m/s, whereas flame cannot be stabilized in the combustor when r = 2.5 mm. Analysis demonstrates that when r = 2.5 mm, flow resistance in the annular space increases drastically and the portion of gaseous mixture that passes through the protruding part increased sharply. Consequently, the low-velocity zone cannot be formed any longer and flame cannot be anchored. Moreover, the heat recirculation efficiency still increases with an increasing r. Therefore, the largest blow-off limit is achieved at r = 2.0 mm.
{"title":"Optimization of a miniature tubular combustor filled with a T-shaped porous zone for flame stability enhancement","authors":"Guangyao Yang, Aiwu Fan","doi":"10.1016/j.fuel.2025.134610","DOIUrl":"10.1016/j.fuel.2025.134610","url":null,"abstract":"<div><div>There exist urgent demands for miniature combustion-based power devices due to their high energy densities. We recently integrated a T-shaped porous zone into a meso-scale combustor with an inner radius (<em>R</em>) of 3 mm. Numerical simulation demonstrated that this new configuration harvested a maximum flame blow-off limit of 1.05 m/s for stoichiometric C<sub>4</sub>H<sub>10</sub>/air mixtures, which is almost twice of the counterpart (0.55 m/s) of original combustor with cylindrical porous media. In the present study, further optimization of this combustor was performed by varying the protruding part radius (<em>r</em>) of the T-shaped porous zone. The findings indicate that as <em>r</em> rises from 0.5 to 2.0 mm, flame blow-off limit keeps increasing to 1.65 m/s, whereas flame cannot be stabilized in the combustor when <em>r</em> = 2.5 mm. Analysis demonstrates that when <em>r</em> = 2.5 mm, flow resistance in the annular space increases drastically and the portion of gaseous mixture that passes through the protruding part increased sharply. Consequently, the low-velocity zone cannot be formed any longer and flame cannot be anchored. Moreover, the heat recirculation efficiency still increases with an increasing <em>r</em>. Therefore, the largest blow-off limit is achieved at <em>r</em> = 2.0 mm.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"391 ","pages":"Article 134610"},"PeriodicalIF":6.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452766","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}
Pub Date : 2025-02-20DOI: 10.1016/j.fuel.2025.134763
Kang-Min Kim , Dong-Won Kim , Gyu-Hwa Lee , Kyoungil Park , Jong-Min Lee , Jungho Hwang
Ammonia (NH3) cofiring represents a promising approach for reducing carbon dioxide (CO2) emissions of power plants using circulating fluidized beds (CFBs). However, the applicability of NH3 cofiring in Asia is unclear owing to limited research. Using a 50 kWth CFB test rig, we performed coal–NH3 cofiring tests and examined how increasing cofiring rates (with 10 % increments between tests) affected temperature inside the furnace and pollutant emissions. Nitric oxide (NO) emission was strongly dependent on the distribution of the atmosphere in the secondary combustion zone, whereas nitrous oxide (N2O) emissions relied on the air distribution in the primary combustion zone. At cofiring rates of up to 30 %, the internal temperature of the furnace and emission of chemical species remained stable, NO emissions were lower than those under the coal-firing condition, whereas carbon monoxide (CO) emissions were relatively high. Practitioners may need to compromise between cofiring rates of 20 % and 30 %, considering the cost of NH3 as fuel and optimizations required to limit N2O emission. Our study supports application of NH3 cofiring technology in CFB boilers in South Korea, highlights the central limitations of the technology, and proposes appropriate optimization steps.
{"title":"Evaluating the limits of ammonia cofiring in a 50 kWth CFB test rig","authors":"Kang-Min Kim , Dong-Won Kim , Gyu-Hwa Lee , Kyoungil Park , Jong-Min Lee , Jungho Hwang","doi":"10.1016/j.fuel.2025.134763","DOIUrl":"10.1016/j.fuel.2025.134763","url":null,"abstract":"<div><div>Ammonia (NH<sub>3</sub>) cofiring represents a promising approach for reducing carbon dioxide (CO<sub>2</sub>) emissions of power plants using circulating fluidized beds (CFBs). However, the applicability of NH<sub>3</sub> cofiring in Asia is unclear owing to limited research. Using a 50 kW<sub>th</sub> CFB test rig, we performed coal–NH<sub>3</sub> cofiring tests and examined how increasing cofiring rates (with 10 % increments between tests) affected temperature inside the furnace and pollutant emissions. Nitric oxide (NO) emission was strongly dependent on the distribution of the atmosphere in the secondary combustion zone, whereas nitrous oxide (N<sub>2</sub>O) emissions relied on the air distribution in the primary combustion zone. At cofiring rates of up to 30 %, the internal temperature of the furnace and emission of chemical species remained stable, NO emissions were lower than those under the coal-firing condition, whereas carbon monoxide (CO) emissions were relatively high. Practitioners may need to compromise between cofiring rates of 20 % and 30 %, considering the cost of NH<sub>3</sub> as fuel and optimizations required to limit N<sub>2</sub>O emission. Our study supports application of NH<sub>3</sub> cofiring technology in CFB boilers in South Korea, highlights the central limitations of the technology, and proposes appropriate optimization steps.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"391 ","pages":"Article 134763"},"PeriodicalIF":6.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452883","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}
Pub Date : 2025-02-20DOI: 10.1016/j.fuel.2025.134677
Zhenkai Bo , Sebastian Hörning , Kunning Tang , Jim R. Underschultz , Suzanne Hurter
Underground Hydrogen Storage (UHS), as an emerging large-scale energy storage technology, has shown great promise to ensure energy security with minimized carbon emission. A set of comprehensive UHS site evaluation criteria based on important factors that affect UHS performances is needed for its potential commercialization. This study focuses on the UHS site evaluation of gas mixing. The economic implications of gas mixing between injected hydrogen gas and the residual or cushion gas in a porous storage reservoir is an emerging problem for Underground Hydrogen Storage (UHS). It is already clear that reservoir scale heterogeneity such as formation structure (e.g. formation dip angle) and facies heterogeneity of the sedimentary rock may considerably affect the reservoir-scale mechanical dispersion-induced gas mixing during UHS in high permeability braided-fluvial systems (a common depleted reservoir type for UHS). Following this finding, the current study uses the process-mimicking modeling software to build synthetic meandering-fluvial reservoir models. Channel dimensions and the presence of abandoned channel facies are set as testing parameters, resulting in 4 simulation cases with 200 realizations. Numerical flow simulations are performed on these models to investigate and compare the effects of reservoir and metre-scale heterogeneity on UHS gas mixing.
Through simulation, channel dimensions (reservoir-scale heterogeneity) are found to affect the uncertainty of produced gas composition due to mixing (represented by the P10-P90 difference of hydrogen fraction in a produced stream) by up to 42%. The presence of abandoned channel facies (metre-scale heterogeneity), depending on their architectural relationship with meander belts, could also influence the gas mixing process to a comparable extent (up to 40%). Moreover, we show that there is no clear statistical correlation between gas mixing and typical reservoir characterization parameters such as original gas in place (OGIP), average reservoir permeability, and the Dykstra-Parsons coefficient. Instead, the average time of travel of all reservoir cells calculated from flow diagnostics shows a negative correlation with the level of gas mixing. These results reveal the importance of 3D reservoir architecture analysis (integration of multiple levels of heterogeneity) to UHS site evaluation on gas mixing in depleted gas reservoirs. This study herein provides valuable insights into UHS site evaluation regarding gas mixing.
{"title":"Insights into site evaluation for underground hydrogen storage (UHS) on gas mixing-the effects of meter-scale heterogeneity and associated reservoir characterization parameters","authors":"Zhenkai Bo , Sebastian Hörning , Kunning Tang , Jim R. Underschultz , Suzanne Hurter","doi":"10.1016/j.fuel.2025.134677","DOIUrl":"10.1016/j.fuel.2025.134677","url":null,"abstract":"<div><div>Underground Hydrogen Storage (UHS), as an emerging large-scale energy storage technology, has shown great promise to ensure energy security with minimized carbon emission. A set of comprehensive UHS site evaluation criteria based on important factors that affect UHS performances is needed for its potential commercialization. This study focuses on the UHS site evaluation of gas mixing. The economic implications of gas mixing between injected hydrogen gas and the residual or cushion gas in a porous storage reservoir is an emerging problem for Underground Hydrogen Storage (UHS). It is already clear that reservoir scale heterogeneity such as formation structure (e.g. formation dip angle) and facies heterogeneity of the sedimentary rock may considerably affect the reservoir-scale mechanical dispersion-induced gas mixing during UHS in high permeability braided-fluvial systems (a common depleted reservoir type for UHS). Following this finding, the current study uses the process-mimicking modeling software to build synthetic meandering-fluvial reservoir models. Channel dimensions and the presence of abandoned channel facies are set as testing parameters, resulting in 4 simulation cases with 200 realizations. Numerical flow simulations are performed on these models to investigate and compare the effects of reservoir and metre-scale heterogeneity on UHS gas mixing.</div><div>Through simulation, channel dimensions (reservoir-scale heterogeneity) are found to affect the uncertainty of produced gas composition due to mixing (represented by the P10-P90 difference of hydrogen fraction in a produced stream) by up to 42%. The presence of abandoned channel facies (metre-scale heterogeneity), depending on their architectural relationship with meander belts, could also influence the gas mixing process to a comparable extent (up to 40%). Moreover, we show that there is no clear statistical correlation between gas mixing and typical reservoir characterization parameters such as original gas in place (OGIP), average reservoir permeability, and the Dykstra-Parsons coefficient. Instead, the average time of travel of all reservoir cells calculated from flow diagnostics shows a negative correlation with the level of gas mixing. These results reveal the importance of 3D reservoir architecture analysis (integration of multiple levels of heterogeneity) to UHS site evaluation on gas mixing in depleted gas reservoirs. This study herein provides valuable insights into UHS site evaluation regarding gas mixing.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"391 ","pages":"Article 134677"},"PeriodicalIF":6.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452885","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号