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.2025.134761
Yaxin Li , Lingqi Zhu , Xueqing Zhang , Yu Zhang , Fusheng Wang , Xiangming Hu
Pyrite is a principal factor affecting the spontaneous combustion of coal; however, the molecular-level structural evolution mechanism of pyrite-containing coal remains unclear. To investigate the mechanisms of pyrite on coal spontaneous combustion, experiments (temperature-programmed experiments, thermogravimetric-differential scanning calorimetry coupled with fourier transform infrared spectroscopy (TG-DSC-FTIR), low-temperature nitrogen adsorption, and in-situ infrared), molecular simulations (reactive force field, ReaxFF) and quantum chemical methods (density functional theory, DFT) were conducted. Experimental results showed that pyrite significantly promoted the generation of CO and CO2, reduced the activation energy of coal samples (4.4%–13%), and increased heat release (14%–46%), thus enhancing the likelihood of coal spontaneous combustion. Additionally, pyrite increased the specific surface area of the coal samples and enhanced the content of active functional groups. ReaxFF molecular dynamics (ReaxFF MD) simulations revealed that pyrite accelerated the decomposition of tar, increased oxygen consumption, and increased the potential energy of the coal–oxygen reaction, thus further promoting coal–oxygen interactions. After the Fe-S bond breaks, Fe, serve as a carrier and repeatedly interacts with the carboxyl oxygen in the benzene ring, thus facilitating the opening of the benzene ring and generating more free radicals. Bond order and interaction force analyses indicated that the presence of Fe2+ reduced the C–C bond energy on the benzene ring, which is consistent with the results of MD simulation.
{"title":"Pyrite-enhanced coal spontaneous combustion: Insights from experiments and molecular simulations","authors":"Yaxin Li , Lingqi Zhu , Xueqing Zhang , Yu Zhang , Fusheng Wang , Xiangming Hu","doi":"10.1016/j.fuel.2025.134761","DOIUrl":"10.1016/j.fuel.2025.134761","url":null,"abstract":"<div><div>Pyrite is a principal factor affecting the spontaneous combustion of coal; however, the molecular-level structural evolution mechanism of pyrite-containing coal remains unclear. To investigate the mechanisms of pyrite on coal spontaneous combustion, experiments (temperature-programmed experiments, thermogravimetric-differential scanning calorimetry coupled with fourier transform infrared spectroscopy (TG-DSC-FTIR), low-temperature nitrogen adsorption, and in-situ infrared), molecular simulations (reactive force field, ReaxFF) and quantum chemical methods (density functional theory, DFT) were conducted. Experimental results showed that pyrite significantly promoted the generation of CO and CO<sub>2</sub>, reduced the activation energy of coal samples (4.4%–13%), and increased heat release (14%–46%), thus enhancing the likelihood of coal spontaneous combustion. Additionally, pyrite increased the specific surface area of the coal samples and enhanced the content of active functional groups. ReaxFF molecular dynamics (ReaxFF MD) simulations revealed that pyrite accelerated the decomposition of tar, increased oxygen consumption, and increased the potential energy of the coal–oxygen reaction, thus further promoting coal–oxygen interactions. After the Fe-S bond breaks, Fe, serve as a carrier and repeatedly interacts with the carboxyl oxygen in the benzene ring, thus facilitating the opening of the benzene ring and generating more free radicals. Bond order and interaction force analyses indicated that the presence of Fe<sup>2+</sup> reduced the C–C bond energy on the benzene ring, which is consistent with the results of MD simulation.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"391 ","pages":"Article 134761"},"PeriodicalIF":6.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445896","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.2025.134712
Louis F. Dacanay , Kevin Wan , Julien Manin , Guillaume De Sercey , Peter J. Cragg , Alain Ledoux , Lionel Estel , Cyril Crua
There is an urgent need to develop energy and space efficient carbon capture technologies for hard to decarbonise sectors. While spray-based carbon capture systems can offer high CO2 absorption rates compared to packed columns, their optimisation requires fine control on spray homogeneity and droplet properties such as size and relative velocity. More specifically, denser mono-disperse sprays with micron scale droplets have been found to increase the rate of CO2 absorption due to increased surface area for mass transfer. One approach that has not previously been investigated is to control the solvent spray properties through flash boiling atomisation to consistently produce fine and homogeneous droplets. To address this gap, we present optical measurements comparing the performance of solvents atomised with varying degrees of flash boiling. Diffuse-back illumination extinction imaging was used for temporal characterisation of spray morphology. We tested a 20:80 ( w/w) blend of triethanolamine and methanol, and neat isopropylamine under six temperature conditions to vary the amount of superheat. Absorption capacities, molar absorption rates, and CO2 percentage removal are reported for each test condition, showing significant improvements at the higher temperature conditions where flash boiling was more intense. While flash boiling carbon capture carries a higher energy demand than conventional technologies, our results offer an innovative and promising avenue for high-efficiency CO2 absorption in hard-to-abate sectors such as marine transportation, especially when coupled with a waste heat recovery strategy.
{"title":"Superheated flash-boiling atomisation effects on spray carbon capture performance using non-aqueous amines","authors":"Louis F. Dacanay , Kevin Wan , Julien Manin , Guillaume De Sercey , Peter J. Cragg , Alain Ledoux , Lionel Estel , Cyril Crua","doi":"10.1016/j.fuel.2025.134712","DOIUrl":"10.1016/j.fuel.2025.134712","url":null,"abstract":"<div><div>There is an urgent need to develop energy and space efficient carbon capture technologies for hard to decarbonise sectors. While spray-based carbon capture systems can offer high CO<sub>2</sub> absorption rates compared to packed columns, their optimisation requires fine control on spray homogeneity and droplet properties such as size and relative velocity. More specifically, denser mono-disperse sprays with micron scale droplets have been found to increase the rate of CO<sub>2</sub> absorption due to increased surface area for mass transfer. One approach that has not previously been investigated is to control the solvent spray properties through flash boiling atomisation to consistently produce fine and homogeneous droplets. To address this gap, we present optical measurements comparing the performance of solvents atomised with varying degrees of flash boiling. Diffuse-back illumination extinction imaging was used for temporal characterisation of spray morphology. We tested a 20:80 (<span><math><mtext>%</mtext></math></span> w/w) blend of triethanolamine and methanol, and neat isopropylamine under six temperature conditions to vary the amount of superheat. Absorption capacities, molar absorption rates, and CO<sub>2</sub> percentage removal are reported for each test condition, showing significant improvements at the higher temperature conditions where flash boiling was more intense. While flash boiling carbon capture carries a higher energy demand than conventional technologies, our results offer an innovative and promising avenue for high-efficiency CO<sub>2</sub> absorption in hard-to-abate sectors such as marine transportation, especially when coupled with a waste heat recovery strategy.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"391 ","pages":"Article 134712"},"PeriodicalIF":6.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452769","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}
Pub Date : 2025-02-20DOI: 10.1016/j.fuel.2025.134668
S. Jiménez , M.C. Mayoral , L.M. Romeo
The combustion of pulverized iron has been studied experimentally in a flat flame reactor in a variety of conditions (high gas temperature, constant [O2] within 4.1–16 %, 75–90 µm). Particle temperature profiles were measured in situ. Samples were collected through rapid cooling in N2 at different residence times in these conditions, resulting in a very detailed characterization of their evolution in terms of internal structure, composition, size and mass. For the latter, a thermogravimetric method has been developed in order to determine the oxidation degree, i.e. the fraction of oxygen in each sample, with considerable advantages over e.g. X-ray diffraction. These new curves for mass vs. distance travelled (as well as the temperature profiles) show a clear gradation with [O2], highlighting iron may indeed be seen as a ‘regular’ fuel and pointing to existing technologies for controlling its oxidation rate and temperature in a potential industrial facility. SEM and XRD give sound evidence for the existence of successive stages in the oxidation process, namely Fe → FeO → Fe3O4 → Fe2O3, with no overlapping between them. In the step Fe → FeO, two clear phases are observed, with a receding iron core surrounded by iron oxide and spontaneous emulsification of both phases. The particles steadily grow when they get oxidized. Statistically significant voids appear in the last stages of oxidation; some particles nearly double their size in these stages. At least two types of particle breakup were observed, but none of them affected noticeably the particle size distribution.
{"title":"Detailed physicochemical evolution of iron particles burnt under controlled, realistic conditions","authors":"S. Jiménez , M.C. Mayoral , L.M. Romeo","doi":"10.1016/j.fuel.2025.134668","DOIUrl":"10.1016/j.fuel.2025.134668","url":null,"abstract":"<div><div>The combustion of pulverized iron has been studied experimentally in a flat flame reactor in a variety of conditions (high gas temperature, constant [O<sub>2</sub>] within 4.1–16 %, 75–90 µm). Particle temperature profiles were measured in situ. Samples were collected through rapid cooling in N<sub>2</sub> at different residence times in these conditions, resulting in a very detailed characterization of their evolution in terms of internal structure, composition, size and mass. For the latter, a thermogravimetric method has been developed in order to determine the oxidation degree, i.e. the fraction of oxygen in each sample, with considerable advantages over e.g. X-ray diffraction. These new curves for mass vs. distance travelled (as well as the temperature profiles) show a clear gradation with [O<sub>2</sub>], highlighting iron may indeed be seen as a ‘regular’ fuel and pointing to existing technologies for controlling its oxidation rate and temperature in a potential industrial facility. SEM and XRD give sound evidence for the existence of successive stages in the oxidation process, namely Fe → FeO → Fe<sub>3</sub>O<sub>4</sub> → Fe<sub>2</sub>O<sub>3</sub>, with no overlapping between them. In the step Fe → FeO, two clear phases are observed, with a receding iron core surrounded by iron oxide and spontaneous emulsification of both phases. The particles steadily grow when they get oxidized. Statistically significant voids appear in the last stages of oxidation; some particles nearly double their size in these stages. At least two types of particle breakup were observed, but none of them affected noticeably the particle size distribution.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"391 ","pages":"Article 134668"},"PeriodicalIF":6.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452832","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}
<div><div>This research delves into the use of water-emulsified diesel fuel within a compression ignition (CI) engine, specifically examining its endurance and the potential for sustainable energy impact. The research aims to standardize constituent levels to achieve a consistent water-in-diesel emulsion fuel, employing an innovative emulsifier, “Propylene Glycol Monostearate,” in conjunction with Tween 80 and octanol as co-emulsifiers. The thorough analysis covers the engine’s operational efficiency, combustion properties, emissions characteristics, and stability during combustion. An electronically controlled 1-cylinder CI engine, operating at a consistent engine speed, was employed for the study, using water-blended diesel fuels identified as “E0, E10, E20, E30, E40, and E50.” The engine’s performance was scrutinized through parameters including BP, BSFC, and thermal efficiency, while combustion aspects such as Combustion Pressure (CP), HRR, ID, CD, and MFB were analyzed. Furthermore, the investigation included an evaluation of emissions such as CO<sub>2</sub>, HC, CO, and NOx. To confirm the combustion knocking intensity behavior, a wavelet analysis approach was implemented by using the model on MATLAB. Despite being prepared under room temperature conditions and stored for a hundred days, all water-in-diesel emulsions displayed consistent stability and uniformity. In terms of engine operation, the BSFC exhibited an upward trend across all emulsions as the brake load increased. The water-in-diesel emulsion displayed equivalent performance in reference to diesel. The Ignition Delay (ID) observed in the emulsions was prolonged in comparison to conventional diesel fuel, that was attributed to their lower cetane value and higher oxygen content. Specifically, the longest delay, reaching up to 37.47%, was noted for the E0 emulsion under full load conditions.</div><div>Amid the various emulsions tested, E50 consistently exhibited the maximum pressure within the engine cylinder across all brake loads. Additionally, the emission of hydrocarbons (HC) from the emulsion fuels surpassed that of diesel across all brake loads. Moreover, the research also investigated the knocking intensity behavior using the wavelet approach with water-in-diesel emulsions. The GWS analysis revealed higher instability or knocking intensity behavior with E0 emulsion at both 25 and 50% loading condition, whereas E50 emulsion showed higher instability or knocking intensity behavior than diesel and other fuels tested. The WPS and GWS results indicated a similar trend for E30 emulsion as observed for diesel fuel.</div><div>To sum up, the mixture of “Propylene Glycol Monostearate” and Tween 80 displays potential novel surfactant to create single phase blends comprising diesel, anhydrous ethanol, and water proving effective across a diverse temperature range. This concoction holds promise as a sustainable engine fuel choice without necessitating extensive engine modifications, cons
{"title":"Combustion knocking intensity behavior analysis using wavelet approach and optimizing water-emulsified diesel fuel: Engine combustion, performance and emission analysis with novel surfactants","authors":"Puneet Singh Gautam, Ajay Partap Singh, Subhash Chand, Asheesh Sehgal","doi":"10.1016/j.fuel.2025.134656","DOIUrl":"10.1016/j.fuel.2025.134656","url":null,"abstract":"<div><div>This research delves into the use of water-emulsified diesel fuel within a compression ignition (CI) engine, specifically examining its endurance and the potential for sustainable energy impact. The research aims to standardize constituent levels to achieve a consistent water-in-diesel emulsion fuel, employing an innovative emulsifier, “Propylene Glycol Monostearate,” in conjunction with Tween 80 and octanol as co-emulsifiers. The thorough analysis covers the engine’s operational efficiency, combustion properties, emissions characteristics, and stability during combustion. An electronically controlled 1-cylinder CI engine, operating at a consistent engine speed, was employed for the study, using water-blended diesel fuels identified as “E0, E10, E20, E30, E40, and E50.” The engine’s performance was scrutinized through parameters including BP, BSFC, and thermal efficiency, while combustion aspects such as Combustion Pressure (CP), HRR, ID, CD, and MFB were analyzed. Furthermore, the investigation included an evaluation of emissions such as CO<sub>2</sub>, HC, CO, and NOx. To confirm the combustion knocking intensity behavior, a wavelet analysis approach was implemented by using the model on MATLAB. Despite being prepared under room temperature conditions and stored for a hundred days, all water-in-diesel emulsions displayed consistent stability and uniformity. In terms of engine operation, the BSFC exhibited an upward trend across all emulsions as the brake load increased. The water-in-diesel emulsion displayed equivalent performance in reference to diesel. The Ignition Delay (ID) observed in the emulsions was prolonged in comparison to conventional diesel fuel, that was attributed to their lower cetane value and higher oxygen content. Specifically, the longest delay, reaching up to 37.47%, was noted for the E0 emulsion under full load conditions.</div><div>Amid the various emulsions tested, E50 consistently exhibited the maximum pressure within the engine cylinder across all brake loads. Additionally, the emission of hydrocarbons (HC) from the emulsion fuels surpassed that of diesel across all brake loads. Moreover, the research also investigated the knocking intensity behavior using the wavelet approach with water-in-diesel emulsions. The GWS analysis revealed higher instability or knocking intensity behavior with E0 emulsion at both 25 and 50% loading condition, whereas E50 emulsion showed higher instability or knocking intensity behavior than diesel and other fuels tested. The WPS and GWS results indicated a similar trend for E30 emulsion as observed for diesel fuel.</div><div>To sum up, the mixture of “Propylene Glycol Monostearate” and Tween 80 displays potential novel surfactant to create single phase blends comprising diesel, anhydrous ethanol, and water proving effective across a diverse temperature range. This concoction holds promise as a sustainable engine fuel choice without necessitating extensive engine modifications, cons","PeriodicalId":325,"journal":{"name":"Fuel","volume":"391 ","pages":"Article 134656"},"PeriodicalIF":6.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452887","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.2025.134748
Gyoung Woo Lee , Kwang Young Kim , Geun Bae Rhim , Hyeon Song Lee , Yeon Hee Ro , Bo Young Lim , Min Hye Youn , Kwan-Young Lee , Dong Hyun Chun
The carbon chemical potential (μc) affects the active phase formation of the Fischer-Tropsch synthesis (FTS) catalyst, which determines catalytic performance and stability. Herein, we report a Zn-promoted precipitated iron-based (Zn-P-Fe) catalyst with enhanced linear alpha-olefin (LAO) yields and stability for high-temperature FTS. This performance improvement is obtained by modulating the μc on the catalyst surface without changing the structural properties. An optimized 10Zn-P-Fe catalyst exhibits a remarkably high C6-C8 LAO selectivity in total hydrocarbon (12.1 %) at high CO Conversion (89.8 %) with 114 h stability under HT-FTS conditions of 305 ℃, 1.5 MPa and H2/CO = 1, outperforming a 0Zn-P-Fe catalyst and other catalysts previously reported in the literature. An analysis of spent catalysts reveals that the superior activity of the 10Zn-P-Fe catalyst can be ascribed to high coke resistance during the reaction. The primary role of the Zn promoter is to reduce μc, which hinders the transformation of the iron carbide phase from Fe5C2 to Fe7C3 and coke formation during the reaction, on the catalyst surface. However, introducing an excessive amount of Zn promoter induces successive olefin hydrogenation on the catalytic surface, resulting in deteriorated olefin selectivity. Therefore, a key factor is maintaining the proper μc by introducing appropriate amounts of Zn promoter.
{"title":"Effect of Zn promoter on precipitated iron catalyst for linear alpha olefin production via high-temperature Fischer-Tropsch synthesis: Modulating carbon chemical potential","authors":"Gyoung Woo Lee , Kwang Young Kim , Geun Bae Rhim , Hyeon Song Lee , Yeon Hee Ro , Bo Young Lim , Min Hye Youn , Kwan-Young Lee , Dong Hyun Chun","doi":"10.1016/j.fuel.2025.134748","DOIUrl":"10.1016/j.fuel.2025.134748","url":null,"abstract":"<div><div>The carbon chemical potential (μ<sub>c</sub>) affects the active phase formation of the Fischer-Tropsch synthesis (FTS) catalyst, which determines catalytic performance and stability. Herein, we report a Zn-promoted precipitated iron-based (Zn-P-Fe) catalyst with enhanced linear alpha-olefin (LAO) yields and stability for high-temperature FTS. This performance improvement is obtained by modulating the μ<sub>c</sub> on the catalyst surface without changing the structural properties. An optimized 10Zn-P-Fe catalyst exhibits a remarkably high C<sub>6</sub>-C<sub>8</sub> LAO selectivity in total hydrocarbon (12.1 %) at high CO Conversion (89.8 %) with 114 h stability under HT-FTS conditions of 305 ℃, 1.5 MPa and H<sub>2</sub>/CO = 1, outperforming a 0Zn-P-Fe catalyst and other catalysts previously reported in the literature. An analysis of spent catalysts reveals that the superior activity of the 10Zn-P-Fe catalyst can be ascribed to high coke resistance during the reaction. The primary role of the Zn promoter is to reduce μ<sub>c</sub>, which hinders the transformation of the iron carbide phase from Fe<sub>5</sub>C<sub>2</sub> to Fe<sub>7</sub>C<sub>3</sub> and coke formation during the reaction, on the catalyst surface. However, introducing an excessive amount of Zn promoter induces successive olefin hydrogenation on the catalytic surface, resulting in deteriorated olefin selectivity. Therefore, a key factor is maintaining the proper μ<sub>c</sub> by introducing appropriate amounts of Zn promoter.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"391 ","pages":"Article 134748"},"PeriodicalIF":6.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445897","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.2025.134685
Bassam A. Najri , Derya Yildiz , Arif Kivrak , Hilal Kivrak
Benzoic acid-functionalized bismuth nanowires (BzOH-Bi NWs) were synthesized using a solvothermal chemical reduction method, where benzoic acid (BzOH) reacted with bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) in dimethylformamide (DMF) at 110 °C. In this approach, benzoic acid served a dual role: it acted as a reducing agent, converting Bi3+ ions to metallic Bi⁰, and as a stabilizing or capping agent, preventing the agglomeration of the nanowires. The resulting BzOH-Bi NWs were characterized using several techniques: X-ray diffraction (XRD) to determine their crystal structures, Fourier-transform infrared spectroscopy (FTIR) to identify molecular bonds and functional groups, scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDX) to assess elemental composition and morphology, and X-ray photoelectron spectroscopy (XPS) to investigate their chemical oxidation states. These BzOH-Bi NWs were then tested as catalysts in the sodium borohydride (NaBH4) methanolysis reaction for hydrogen production. The BzOH-Bi NWs exhibited exceptional catalytic activity, achieving a hydrogen production rate (HPR) of 42.32 L/min.gcatalyst when using 5 mg of BzOH-Bi NWs, 125 mg of NaBH4, and 4 mL of methanol at 30 °C. The activation energy of the reaction was calculated to be 18.6 kJ/mol using the Arrhenius equation. Furthermore, the catalysts demonstrated excellent reusability, maintaining high performance over 5 cycles, highlighting their potential as highly effective catalysts for hydrogen generation.
{"title":"Benzoic acid-functionalized bismuth nanowires: Synthesis, characterization, and catalytic role in hydrogen generation via sodium borohydride methanolysis","authors":"Bassam A. Najri , Derya Yildiz , Arif Kivrak , Hilal Kivrak","doi":"10.1016/j.fuel.2025.134685","DOIUrl":"10.1016/j.fuel.2025.134685","url":null,"abstract":"<div><div>Benzoic acid-functionalized bismuth nanowires (BzOH-Bi NWs) were synthesized using a solvothermal chemical reduction method, where benzoic acid (BzOH) reacted with bismuth nitrate pentahydrate (Bi(NO<sub>3</sub>)<sub>3</sub>·5H<sub>2</sub>O) in dimethylformamide (DMF) at 110 °C. In this approach, benzoic acid served a dual role: it acted as a reducing agent, converting Bi<sup>3+</sup> ions to metallic Bi⁰, and as a stabilizing or capping agent, preventing the agglomeration of the nanowires. The resulting BzOH-Bi NWs were characterized using several techniques: X-ray diffraction (XRD) to determine their crystal structures, Fourier-transform infrared spectroscopy (FTIR) to identify molecular bonds and functional groups, scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDX) to assess elemental composition and morphology, and X-ray photoelectron spectroscopy (XPS) to investigate their chemical oxidation states. These BzOH-Bi NWs were then tested as catalysts in the sodium borohydride (NaBH<sub>4</sub>) methanolysis reaction for hydrogen production. The BzOH-Bi NWs exhibited exceptional catalytic activity, achieving a hydrogen production rate (HPR) of 42.32 L/min.g<sub>catalyst</sub> when using 5 mg of BzOH-Bi NWs, 125 mg of NaBH<sub>4</sub>, and 4 mL of methanol at 30 °C. The activation energy of the reaction was calculated to be 18.6 kJ/mol using the Arrhenius equation. Furthermore, the catalysts demonstrated excellent reusability, maintaining high performance over 5 cycles, highlighting their potential as highly effective catalysts for hydrogen generation.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"390 ","pages":"Article 134685"},"PeriodicalIF":6.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445060","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.2025.134785
Hang Guo , Jia-He Lv , Run-Dong He , Bin He , Xiao-Ling Dong , Wen-Cui Li
Biomass has gained significant attention as a promising precursor for preparing hard carbon anodes in sodium-ion batteries (SIBs), yet the influence of minerals in biomass on both material pyrolysis and sodium storage processes is not clear enough. Herein, we introduce alumina into the cellulose and lignin, which are the primary components of biomass, to elucidate the influence of alumina on the structure and sodium storage performance of biomass-based hard carbons. When cellulose serves as the precursor, alumina enlarges the interlayer spacing by impeding the growth and arrangement of carbon microcrystals. With the increase in alumina content, it initially creates open pores by facilitating the evaporation of volatile and hindering micropores closure, followed by subsequently blocking them to form closed pores, providing more active sites for Na+ storage in the low-voltage plateau region. As a result, the carbon derived from cellulose mixed with 1 wt% alumina demonstrates both higher initial Coulombic efficiency (82.4 %) and plateau capacity (127.1 mAh g−1) at 0.02 A g−1, compared to the hard carbon in the absence of alumina (77.2 % and 113.5 mAh g−1). Additionally, alumina with more weak acid sites can be more conducive to catalyzing hydroxyl dehydration, thereby enhancing the pore-creating effect of volatile. The similar performance enhancements are not observed in lignin-based carbons due to the lower volatile content and larger steric hindrance of lignin. This study provides new insights into the influence of alumina on structures of hard carbon, which will promote the application of alumina on cellulose-rich precursors to improve the electrochemical performance.
生物质作为制备钠离子电池（SIB）中硬碳阳极的一种前景广阔的前驱体，已经引起了人们的极大关注，然而生物质中的矿物质对材料热解和储钠过程的影响还不够清楚。在此，我们在生物质的主要成分纤维素和木质素中引入氧化铝，以阐明氧化铝对生物质基硬碳的结构和储钠性能的影响。当纤维素作为前驱体时，氧化铝会阻碍碳微晶的生长和排列，从而扩大层间间距。随着氧化铝含量的增加，氧化铝最初会通过促进挥发物的蒸发和阻碍微孔的闭合来形成开放孔隙，随后又会阻塞微孔形成封闭孔隙，为低电压高原区的 Na+ 储存提供更多的活性位点。因此，与不含氧化铝的硬质碳（77.2% 和 113.5 mAh g-1）相比，混合了 1 wt% 氧化铝的纤维素衍生碳在 0.02 A g-1 下显示出更高的初始库仑效率（82.4%）和高原容量（127.1 mAh g-1）。此外，具有更多弱酸位点的氧化铝更有利于催化羟基脱水，从而增强挥发性的孔隙生成效果。由于木质素的挥发物含量较低且立体阻碍较大，因此在木质素基碳中没有观察到类似的性能增强。这项研究为了解氧化铝对硬质碳结构的影响提供了新的视角，这将促进氧化铝在富含纤维素的前驱体上的应用，从而提高电化学性能。
{"title":"Elucidating the influence of alumina mineral on sodium storage performance of biomass-derived hard carbon anode","authors":"Hang Guo , Jia-He Lv , Run-Dong He , Bin He , Xiao-Ling Dong , Wen-Cui Li","doi":"10.1016/j.fuel.2025.134785","DOIUrl":"10.1016/j.fuel.2025.134785","url":null,"abstract":"<div><div>Biomass has gained significant attention as a promising precursor for preparing hard carbon anodes in sodium-ion batteries (SIBs), yet the influence of minerals in biomass on both material pyrolysis and sodium storage processes is not clear enough. Herein, we introduce alumina into the cellulose and lignin, which are the primary components of biomass, to elucidate the influence of alumina on the structure and sodium storage performance of biomass-based hard carbons. When cellulose serves as the precursor, alumina enlarges the interlayer spacing by impeding the growth and arrangement of carbon microcrystals. With the increase in alumina content, it initially creates open pores by facilitating the evaporation of volatile and hindering micropores closure, followed by subsequently blocking them to form closed pores, providing more active sites for Na<sup>+</sup> storage in the low-voltage plateau region. As a result, the carbon derived from cellulose mixed with 1 wt% alumina demonstrates both higher initial Coulombic efficiency (82.4 %) and plateau capacity (127.1 mAh g<sup>−1</sup>) at 0.02 A g<sup>−1</sup>, compared to the hard carbon in the absence of alumina (77.2 % and 113.5 mAh g<sup>−1</sup>). Additionally, alumina with more weak acid sites can be more conducive to catalyzing hydroxyl dehydration, thereby enhancing the pore-creating effect of volatile. The similar performance enhancements are not observed in lignin-based carbons due to the lower volatile content and larger steric hindrance of lignin. This study provides new insights into the influence of alumina on structures of hard carbon, which will promote the application of alumina on cellulose-rich precursors to improve the electrochemical performance.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"390 ","pages":"Article 134785"},"PeriodicalIF":6.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445059","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.2025.134772
Putrakumar Balla , Daeseob Shin , Seon-Ju Park , Geunjae Kwak , Sungtak Kim
Using 3D printing to fabricate catalysts is regarded as a revolutionary process with numerous advantages. This technique can enhance the efficiency and cost-effectiveness of catalyst synthesis. Methanol steam reforming (MSR) is a promising technology for in-vehicle hydrogen generation. In this study, a wood-pile structured 3D Cu/Al2O3 catalyst was manufactured using a 3D printing process and evaluated for MSR reaction in a fixed bed reactor operating at atmospheric H2 pressure. The characterization study of the 3D catalyst was carried out in terms of textural properties, composition, morphology, and active sites. The MSR reaction was performed for different operating parameters, such as reaction temperature, WHSV, and stability. In similar reaction conditions, we compared this 3D Cu/Al2O3 catalyst with a bead-type Cu/Al2O3 catalyst. The rate of reaction for both catalysts was calculated using the activity data. 3D Cu/Al2O3 catalyst exhibits a higher value than bead-type catalyst, indicating that 3D Cu/Al2O3 catalysts possess higher active sites, which is in accordance with their catalytic activity.
{"title":"Investigating copper impregnated 3D printed Al2O3 catalyst for methanol steam reforming","authors":"Putrakumar Balla , Daeseob Shin , Seon-Ju Park , Geunjae Kwak , Sungtak Kim","doi":"10.1016/j.fuel.2025.134772","DOIUrl":"10.1016/j.fuel.2025.134772","url":null,"abstract":"<div><div>Using 3D printing to fabricate catalysts is regarded as a revolutionary process with numerous advantages. This technique can enhance the efficiency and cost-effectiveness of catalyst synthesis. Methanol steam reforming (MSR) is a promising technology for in-vehicle hydrogen generation. In this study, a wood-pile structured 3D Cu/Al<sub>2</sub>O<sub>3</sub> catalyst was manufactured using a 3D printing process and evaluated for MSR reaction in a fixed bed reactor operating at atmospheric H<sub>2</sub> pressure. The characterization study of the 3D catalyst was carried out in terms of textural properties, composition, morphology, and active sites. The MSR reaction was performed for different operating parameters, such as reaction temperature, WHSV, and stability. In similar reaction conditions, we compared this 3D Cu/Al<sub>2</sub>O<sub>3</sub> catalyst with a bead-type Cu/Al<sub>2</sub>O<sub>3</sub> catalyst. The rate of reaction for both catalysts was calculated using the activity data. 3D Cu/Al<sub>2</sub>O<sub>3</sub> catalyst exhibits a higher value than bead-type catalyst, indicating that 3D Cu/Al<sub>2</sub>O<sub>3</sub> catalysts possess higher active sites, which is in accordance with their catalytic activity.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"390 ","pages":"Article 134772"},"PeriodicalIF":6.7,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143444962","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}
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