Pub Date : 2025-02-17DOI: 10.1016/j.fuel.2025.134651
Yanpeng Pei , Xinyan Qiu , Li Wang , Sibudjing Kawi
CO2 methanation is a promising approach for simultaneously valorizing CO2 while displacing fossil-derived methane. Although Ni is a well-known earth-abundant methanation catalyst, achieving high activity at low reaction temperatures requires a combination of well-dispersed Ni, proper basicity, and abundant surface oxygen vacancies that is often difficult to achieve over an inert support such as SiO2. Here, we demonstrate the synthesis of active, selective, and stable SiO2-supported Ni (Ni/SiO2) catalysts for low-temperature methanation via the direct H2 reduction of dried sol–gel precursors. At the optimal H2 reduction temperature of 400 °C, above 40 % CO2 conversion and essentially 100 % methane selectivity could be achieved at a reaction temperature of 200 °C (P = 1 bar and GHSV = 8,000 mL⋅gcat.−1⋅h−1). A comprehensive suite of characterizations revealed well-dispersed Ni together with moderate basicity engendered by Ni-O-Si sites. Notably, these Ni-O-Si sites are lost upon air calcination or partially destroyed under higher-temperature H2 pretreatment, highlighting the important effect of pretreatment conditions on catalyst performance. Further, in-situ DRIFTS analysis linked the superior performance of the best catalyst to a high concentration of surface carbonyl intermediates. Overall, these findings not only provide valuable insights into sol–gel syntheses and low-temperature CO2 methanation, but also reveal a simple, scalable, and cost-effective route towards low-temperature methanation catalysts with prospective industrial applications.
{"title":"Low-temperature CO2 methanation over SiO2 supported Ni catalysts derived from sol-gel precursors: Effect of pretreatment process","authors":"Yanpeng Pei , Xinyan Qiu , Li Wang , Sibudjing Kawi","doi":"10.1016/j.fuel.2025.134651","DOIUrl":"10.1016/j.fuel.2025.134651","url":null,"abstract":"<div><div>CO<sub>2</sub> methanation is a promising approach for simultaneously valorizing CO<sub>2</sub> while displacing fossil-derived methane. Although Ni is a well-known earth-abundant methanation catalyst, achieving high activity at low reaction temperatures requires a combination of well-dispersed Ni, proper basicity, and abundant surface oxygen vacancies that is often difficult to achieve over an inert support such as SiO<sub>2</sub>. Here, we demonstrate the synthesis of active, selective, and stable SiO<sub>2</sub>-supported Ni (Ni/SiO<sub>2</sub>) catalysts for low-temperature methanation via the direct H<sub>2</sub> reduction of dried sol–gel precursors. At the optimal H<sub>2</sub> reduction temperature of 400 °C, above 40 % CO<sub>2</sub> conversion and essentially 100 % methane selectivity could be achieved at a reaction temperature of 200 °C (P = 1 bar and GHSV = 8,000 mL⋅g<sub>cat.</sub><sup>−1</sup>⋅h<sup>−1</sup>). A comprehensive suite of characterizations revealed well-dispersed Ni together with moderate basicity engendered by Ni-O-Si sites. Notably, these Ni-O-Si sites are lost upon air calcination or partially destroyed under higher-temperature H<sub>2</sub> pretreatment, highlighting the important effect of pretreatment conditions on catalyst performance. Further, in-situ DRIFTS analysis linked the superior performance of the best catalyst to a high concentration of surface carbonyl intermediates. Overall, these findings not only provide valuable insights into sol–gel syntheses and low-temperature CO<sub>2</sub> methanation, but also reveal a simple, scalable, and cost-effective route towards low-temperature methanation catalysts with prospective industrial applications.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"390 ","pages":"Article 134651"},"PeriodicalIF":6.7,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422587","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 : 2025-02-17DOI: 10.1016/j.fuel.2025.134514
Yonghyun Lee , Jaehun Choi , Hyoung-il Kim , Jungho Jae , Jung Rae Kim , Sang Hwan Son
The increasing global demand for sustainable energy and the need to reduce greenhouse gas emissions have driven interest in renewable fuels such as biodiesel. However, conventional biodiesels commonly exhibit limitations in oxidation stability and low-temperature operability, which restrict their blendability with petroleum diesel. Hydrotreated biodiesel (HBD), produced by hydrotreating vegetable oils, offers improved fuel properties, making it a promising alternative. This study addresses challenges in cost-effective industrial-scale HBD production by developing a modeling and optimization framework for a trickle-bed reactor (TBR) equipped with quench zones. Specifically, a kinetic study was conducted to identify the most suitable reaction rate model, followed by the construction of a pilot-scale hydrotreating TBR model based on the selected kinetics, validated against experimental data. Among the kinetic models evaluated, the A3 kinetic model demonstrated robust accuracy, with R-square values of 0.9889. To manage the exothermic heat of hydrotreatment reactions, quench zones utilizing hydrogen were strategically introduced between reactor beds to prevent hotspot formation. Then, economic optimization was performed, considering hydrogen recovery and utility usage in the entire production process, including units such as three-phase separator, H-pressure swing adsorption, and multistage compressors. The results demonstrated that the optimal quench zone design and operating conditions could effectively enhance the economic feasibility by significantly reducing the required amount of quenching hydrogen while maintaining high HBD yield. Specifically, HBD revenue increased by 5.01%, electricity costs decreased by 4.36%, and chilled water costs were reduced by 2.86%. Overall, the optimal case achieved a 25.17% improvement in profitability compared with the base case.
{"title":"Modeling and optimization of a trickle-bed reactor with hydrogen quenching for cost-effective hydrotreated biodiesel production","authors":"Yonghyun Lee , Jaehun Choi , Hyoung-il Kim , Jungho Jae , Jung Rae Kim , Sang Hwan Son","doi":"10.1016/j.fuel.2025.134514","DOIUrl":"10.1016/j.fuel.2025.134514","url":null,"abstract":"<div><div>The increasing global demand for sustainable energy and the need to reduce greenhouse gas emissions have driven interest in renewable fuels such as biodiesel. However, conventional biodiesels commonly exhibit limitations in oxidation stability and low-temperature operability, which restrict their blendability with petroleum diesel. Hydrotreated biodiesel (HBD), produced by hydrotreating vegetable oils, offers improved fuel properties, making it a promising alternative. This study addresses challenges in cost-effective industrial-scale HBD production by developing a modeling and optimization framework for a trickle-bed reactor (TBR) equipped with quench zones. Specifically, a kinetic study was conducted to identify the most suitable reaction rate model, followed by the construction of a pilot-scale hydrotreating TBR model based on the selected kinetics, validated against experimental data. Among the kinetic models evaluated, the A3 kinetic model demonstrated robust accuracy, with R-square values of 0.9889. To manage the exothermic heat of hydrotreatment reactions, quench zones utilizing hydrogen were strategically introduced between reactor beds to prevent hotspot formation. Then, economic optimization was performed, considering hydrogen recovery and utility usage in the entire production process, including units such as three-phase separator, H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-pressure swing adsorption, and multistage compressors. The results demonstrated that the optimal quench zone design and operating conditions could effectively enhance the economic feasibility by significantly reducing the required amount of quenching hydrogen while maintaining high HBD yield. Specifically, HBD revenue increased by 5.01%, electricity costs decreased by 4.36%, and chilled water costs were reduced by 2.86%. Overall, the optimal case achieved a 25.17% improvement in profitability compared with the base case.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"390 ","pages":"Article 134514"},"PeriodicalIF":6.7,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422613","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 : 2025-02-17DOI: 10.1016/j.fuel.2025.134722
Subhadarsi Nayak, Gopika S. Madhu, Balla Rajakumar
A keto-ether compound, 1-methoxy butan-2-one (MB2O), represents a novel biofuel. Understanding the pyrolysis chemistry of MB2O in its entirety is crucial. H-abstraction reactions by H-atoms and CH3-radicals are commonly involved in combustion mechanisms. Our study involves the computation of kinetic parameters, emphasizing the contribution of thermodynamic factors to determine the rate coefficient for homolytic bond cleavage reactions and H-abstraction reactions initiated by H atoms and CH3 radicals. The thermodynamic parameters were obtained using the G3B3 quantum composite method and were compared with the results obtained using the M06-2X/aug-cc-pVTZ method and the CBS-QB3 method. A detailed study was conducted on the potential energy surface (PES) for homolytic bond cleavages and H-abstraction reactions. Canonical transition state theory (CTST) and variational transition state theory (VTST) were used to theoretically determine the rate coefficient values for H-abstraction and homolytic bond cleavage reactions, respectively, in the 500–2000 K temperature range. A key aspect of this work is comparing MB2O to the well-studied biofuel methyl butanoate (MB), its structural isomer. MB2O was found to combust faster than MB. The site-specific reactivity of MB2O was also explored by calculating the various local descriptors such as Fukui functions () and local softness ().
{"title":"Thermo-kinetic theoretical studies on the homolytic bond cleavages and H-abstractions of 1-methoxy butan-2-one, a keto-ether fuel additive","authors":"Subhadarsi Nayak, Gopika S. Madhu, Balla Rajakumar","doi":"10.1016/j.fuel.2025.134722","DOIUrl":"10.1016/j.fuel.2025.134722","url":null,"abstract":"<div><div>A keto-ether compound, 1-methoxy butan-2-one (MB2O), represents a novel biofuel. Understanding the pyrolysis chemistry of MB2O in its entirety is crucial. H-abstraction reactions by H-atoms and CH<sub>3</sub>-radicals are commonly involved in combustion mechanisms. Our study involves the computation of kinetic parameters, emphasizing the contribution of thermodynamic factors to determine the rate coefficient for homolytic bond cleavage reactions and H-abstraction reactions initiated by H atoms and CH<sub>3</sub> radicals. The thermodynamic parameters were obtained using the G3B3 quantum composite method and were compared with the results obtained using the M06-2X/aug-cc-pVTZ method and the CBS-QB3 method. A detailed study was conducted on the potential energy surface (PES) for homolytic bond cleavages and H-abstraction reactions. Canonical transition state theory (CTST) and variational transition state theory (VTST) were used to theoretically determine the rate coefficient values for H-abstraction and homolytic bond cleavage reactions, respectively, in the 500–2000 K temperature range. A key aspect of this work is comparing MB2O to the well-studied biofuel methyl butanoate (MB), its structural isomer. MB2O was found to combust faster than MB. The site-specific reactivity of MB2O was also explored by calculating the various local descriptors such as Fukui functions (<span><math><msubsup><mi>f</mi><mrow><mi>r</mi></mrow><mn>0</mn></msubsup></math></span>) and local softness (<span><math><msubsup><mi>s</mi><mrow><mi>r</mi></mrow><mn>0</mn></msubsup></math></span>).</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"390 ","pages":"Article 134722"},"PeriodicalIF":6.7,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422638","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 : 2025-02-17DOI: 10.1016/j.fuel.2025.134742
Junwei Liu, Bingwen Li, Huiyu Tian, Jinxian Zhao
The semi-hydrogenation of biomass-derived furfural (FAL) to furfuryl alcohol (FOL) has great significance for sustainable development of energy. Cu-based catalysts have been reported to be highly selective for FOL, but typically exhibit relatively low hydrogenation activity. Herein, Cu/xNC and Cu-Cay/6NC catalysts with different nitrogen contents and Cu/Ca molar ratios were prepared and applied to the FAL hydrogenation. The optimized Cu-Ca2.0/6NC catalysts exhibited glorious catalytic performance with complete FAL conversion and 99.5 % FOL selectivity under 4 MPa and 150 ℃ and outstanding stability. It was found that the FAL conversion, as well as the FOL selectivity, is in good positive correlation with the Cu+ content. Additionally, the apparent activation energy for FAL hydrogenation was reduced by the addition of CaO, possibly ascribed to the strong electronic interaction between CaO and Cu species, which not only improved the Cu dispersion, but also stabilized the Cu+ species in the catalyst. This work could offer a potential strategy for the design of promising Cu catalyst for FAL hydrogenation.
{"title":"Enhanced catalytic performance of Cu/NC catalyst for hydrogenation of furfural to furfuryl alcohol: Effective stabilization of Cu+ with CaO promoter","authors":"Junwei Liu, Bingwen Li, Huiyu Tian, Jinxian Zhao","doi":"10.1016/j.fuel.2025.134742","DOIUrl":"10.1016/j.fuel.2025.134742","url":null,"abstract":"<div><div>The semi-hydrogenation of biomass-derived furfural (FAL) to furfuryl alcohol (FOL) has great significance for sustainable development of energy. Cu-based catalysts have been reported to be highly selective for FOL, but typically exhibit relatively low hydrogenation activity. Herein, Cu/<em>x</em>NC and Cu-Ca<em><sub>y</sub></em>/6NC catalysts with different nitrogen contents and Cu/Ca molar ratios were prepared and applied to the FAL hydrogenation. The optimized Cu-Ca<sub>2.0</sub>/6NC catalysts exhibited glorious catalytic performance with complete FAL conversion and 99.5 % FOL selectivity under 4 MPa and 150 ℃ and outstanding stability. It was found that the FAL conversion, as well as the FOL selectivity, is in good positive correlation with the Cu<sup>+</sup> content. Additionally, the apparent activation energy for FAL hydrogenation was reduced by the addition of CaO, possibly ascribed to the strong electronic interaction between CaO and Cu species, which not only improved the Cu dispersion, but also stabilized the Cu<sup>+</sup> species in the catalyst. This work could offer a potential strategy for the design of promising Cu catalyst for FAL hydrogenation.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"390 ","pages":"Article 134742"},"PeriodicalIF":6.7,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430248","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}
Zeolites catalyzed aromatization is important process for value-added utilization of light alkanes. This paper report the effect of zeolite types on the aromatization of propane. ZSM-35 (8, 10-MR), ZSM-5 (10, 10-MR), and MCM-22 (10, 12-MR) zeolites were modified with Zn and employed as catalysts of propane aromatization. The results showed that there is no significant difference in the amount of [ZnOH]+ and ZnO species among three zeolites, the major influence to aromatization come from pore structures and their acidities. Online analysis at reactor outlet to the evaporable products indicate that, Zn/ZSM-35 catalyst exhibits lowest propane conversion, weak aromatization performance and rapid deactivation characteristics, conversely, its olefin selectivity reaches a high level. Zn/ZSM-5 catalyst shows the best propane conversion rate, aromatization activity and stability, it also shows the highest naphthalenes selectivity. Zn/MCM-22 zeolite exhibits moderate propane conversion rate, aromatics/olefin selectivity, and it shows higher alkylbenzene selectivity but low naphthalenes selectivity in aromatics, this is due to its 10, 12-membered ring pore channel. Here also provides data about the high boiling point non-evaporable polycyclic aromatics (PAHs), which is deposit on the catalyst in soluble coke form. TG analysis of spent catalyst found that Zn/ZSM-5 catalyst has the smallest amount of coke and PAHs form of coking precursor, only 1.3 %, while Zn/MCM-22 shows the highest data of 8.6 %, that of Zn/ZSM-35 is 5.1 %. The PAHs on the external surface area of catalyst were obtained by extraction with toluene, the PAHs inside zeolite pores were obtained by toluene extraction after the above extraction step and then HF destruction to the zeolite framework. FT-ICR MS analysis data indicates that PAHs inside Zn/ZSM-35, Zn/ZSM-5 and Zn/MCM-22 pore consist of 2–5, 3–5 and 3–6 aromatic rings, and PAHs on the external surface is about one aromatic ring more than the PAHs inside the pores. The low selectivity of Zn/MCM-22 to naphthalenes is attributed to large pore space of it, it makes the generated naphthalenes undergo a condensation reaction to coke. It shows a good correlation between aromatics distribution, catalyst pore structure and acidity. The aromatics distribution data are valuable information for industrial catalyst and process design.
{"title":"The regulating effect of zeolite types on catalytic aromatization of propane: The distributions of evaporable aromatics and non-evaporable polycyclic aromatics","authors":"Yue Ma, Lingxiang Huang, Yuhang Tan, Haitao An, Qiang Zhang, Chunming Xu, Baojian Shen","doi":"10.1016/j.fuel.2025.134659","DOIUrl":"10.1016/j.fuel.2025.134659","url":null,"abstract":"<div><div>Zeolites catalyzed aromatization is important process for value-added utilization of light alkanes. This paper report the effect of zeolite types on the aromatization of propane. ZSM-35 (8, 10-MR), ZSM-5 (10, 10-MR), and MCM-22 (10, 12-MR) zeolites were modified with Zn and employed as catalysts of propane aromatization. The results showed that there is no significant difference in the amount of [ZnOH]<sup>+</sup> and ZnO species among three zeolites, the major influence to aromatization come from pore structures and their acidities. Online analysis at reactor outlet to the evaporable products indicate that, Zn/ZSM-35 catalyst exhibits lowest propane conversion, weak aromatization performance and rapid deactivation characteristics, conversely, its olefin selectivity reaches a high level. Zn/ZSM-5 catalyst shows the best propane conversion rate, aromatization activity and stability, it also shows the highest naphthalenes selectivity. Zn/MCM-22 zeolite exhibits moderate propane conversion rate, aromatics/olefin selectivity, and it shows higher alkylbenzene selectivity but low naphthalenes selectivity in aromatics, this is due to its 10, 12-membered ring pore channel. Here also provides data about the high boiling point non-evaporable polycyclic aromatics (PAHs), which is deposit on the catalyst in soluble coke form. TG analysis of spent catalyst found that Zn/ZSM-5 catalyst has the smallest amount of coke and PAHs form of coking precursor, only 1.3 %, while Zn/MCM-22 shows the highest data of 8.6 %, that of Zn/ZSM-35 is 5.1 %. The PAHs on the external surface area of catalyst were obtained by extraction with toluene, the PAHs inside zeolite pores were obtained by toluene extraction after the above extraction step and then HF destruction to the zeolite framework. FT-ICR MS analysis data indicates that PAHs inside Zn/ZSM-35, Zn/ZSM-5 and Zn/MCM-22 pore consist of 2–5, 3–5 and 3–6 aromatic rings, and PAHs on the external surface is about one aromatic ring more than the PAHs inside the pores. The low selectivity of Zn/MCM-22 to naphthalenes is attributed to large pore space of it, it makes the generated naphthalenes undergo a condensation reaction to coke. It shows a good correlation between aromatics distribution, catalyst pore structure and acidity. The aromatics distribution data are valuable information for industrial catalyst and process design.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"390 ","pages":"Article 134659"},"PeriodicalIF":6.7,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430253","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 : 2025-02-16DOI: 10.1016/j.fuel.2025.134698
Xu He , Chengyuan Zhao , Guangyuan Feng , Xiaoran Zhou , Zechang Liu , Zhi Wang , Qingchu Chen
In recent years, pentanone, a biomass-derived fuel, has attracted significant attention in the field of combustion due to its excellent anti-knock properties and high energy density. To address the low reactivity inherent in ammonia (NH3) combustion, blending pentanone with NH3 has emerged as a promising strategy. This study investigates laminar burning velocities (LBVs) of 2-pentanone (nPMK)/NH3 mixtures at pressures of 1 atm and 3 atm, with a temperature of 448 K and nPMK mole fractions ranging from 0.1 to 1.0. Additionally, building upon the authors’ previous research on 3-pentanone (DEK)/NH3 mixtures, a comparative analysis was conducted to evaluate the effects of both linear pentanone isomers on NH3 flame propagation. The kinetic model utilized is an extension of an earlier pentanone-NH3 model, which has been further refined using the latest experimental data and prior research findings. The results show that blending 50 % DEK with NH3 can increase LBV by up to 350 % compared to pure NH3-air mixtures, while nPMK achieves a maximum LBV increase of 300 %, underscoring pentanone’s potential to enhance NH3 combustion performance. Under stoichiometric conditions, the LBV of DEK/NH3-air mixtures is consistently 3–4 cm/s higher than that of nPMK/NH3-air mixtures, suggesting that DEK is more effective in improving NH3 combustion characteristics. Kinetic analysis reveals the difference in LBV is primarily attributable to variations in radical concentrations. Specifically, the position of the carbonyl group in each isomer results in different oxidation intermediates (i.e., CH3 for nPMK and C2H5 for DEK). In nPMK/NH3-air flames, CH3 primarily participates in the chain-terminating reaction CH3 + H(+M) = CH4(+M), consuming significant quantities of H radicals and suppressing flame propagation. In contrast, C2H5 in DEK undergo -C–H bond scission, generating H radicals that promote flame propagation. Consequently, DEK/NH3-air mixtures exhibit higher reactivity and faster LBVs.
{"title":"Kinetic modeling and experimental investigation of laminar burning velocity in 2- and 3-pentanone/ammonia premixed flames","authors":"Xu He , Chengyuan Zhao , Guangyuan Feng , Xiaoran Zhou , Zechang Liu , Zhi Wang , Qingchu Chen","doi":"10.1016/j.fuel.2025.134698","DOIUrl":"10.1016/j.fuel.2025.134698","url":null,"abstract":"<div><div>In recent years, pentanone, a biomass-derived fuel, has attracted significant attention in the field of combustion due to its excellent anti-knock properties and high energy density. To address the low reactivity inherent in ammonia (NH<sub>3</sub>) combustion, blending pentanone with NH<sub>3</sub> has emerged as a promising strategy. This study investigates laminar burning velocities (LBVs) of 2-pentanone (nPMK)/NH<sub>3</sub> mixtures at pressures of 1 atm and 3 atm, with a temperature of 448 K and nPMK mole fractions ranging from 0.1 to 1.0. Additionally, building upon the authors’ previous research on 3-pentanone (DEK)/NH<sub>3</sub> mixtures, a comparative analysis was conducted to evaluate the effects of both linear pentanone isomers on NH<sub>3</sub> flame propagation. The kinetic model utilized is an extension of an earlier pentanone-NH<sub>3</sub> model, which has been further refined using the latest experimental data and prior research findings. The results show that blending 50 % DEK with NH<sub>3</sub> can increase LBV by up to 350 % compared to pure NH<sub>3</sub>-air mixtures, while nPMK achieves a maximum LBV increase of 300 %, underscoring pentanone’s potential to enhance NH<sub>3</sub> combustion performance. Under stoichiometric conditions, the LBV of DEK/NH<sub>3</sub>-air mixtures is consistently 3–4 cm/s higher than that of nPMK/NH<sub>3</sub>-air mixtures, suggesting that DEK is more effective in improving NH<sub>3</sub> combustion characteristics. Kinetic analysis reveals the difference in LBV is primarily attributable to variations in radical concentrations. Specifically, the position of the carbonyl group in each isomer results in different oxidation intermediates (i.e., CH<sub>3</sub> for nPMK and C<sub>2</sub>H<sub>5</sub> for DEK). In nPMK/NH<sub>3</sub>-air flames, CH<sub>3</sub> primarily participates in the chain-terminating reaction CH<sub>3</sub> + H(+M) = CH<sub>4</sub>(+M), consuming significant quantities of H radicals and suppressing flame propagation. In contrast, C<sub>2</sub>H<sub>5</sub> in DEK undergo <span><math><mi>β</mi></math></span>-C–H bond scission, generating H radicals that promote flame propagation. Consequently, DEK/NH<sub>3</sub>-air mixtures exhibit higher reactivity and faster LBVs.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"390 ","pages":"Article 134698"},"PeriodicalIF":6.7,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422223","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 : 2025-02-16DOI: 10.1016/j.fuel.2025.134652
Wei Wang, Mingfeng Li, Yang Zhang, Kang Qin, Li Zhuang, Ping Yang, Hong Nie
Oriented conversion of poly-aromatic hydrocarbons into benzene, toluene, and xylene (BTX) via selective hydrocracking is an effective way to upgrade low-quality fossil oils into high-valued products. An in-depth understanding of the structure-performance relationship is crucial to the further improvement of catalytic activity and selectivity. Zeolites are essential components of hydrocracking catalysts, of which pore structure and acid properties significantly influence the catalytic performance. However, the structure-performance relationship between them is multifactorial, and it’s quite difficult to be investigated using traditional experimental method which needs a large series of univariate samples. In this study, the multifactorial relationship was built with the help of machine learning modeling based on the dataset derived from the characterization of fifteen zeolite samples and the catalytic performance of the corresponding catalysts. Based on the model’s prediction, the effect of pore and acidity properties was quantitatively described. Mesopores were observed to have a great influence on conversion, while micropores have a great improvement in BTX selectivity. The amount of total acid was observed to have a significant effect on both conversion and selectivity. To get more insight into the intrinsic mechanism of the structure-performance relationship, more characterization of the spent catalysts was carried on. It was demonstrated that the properties of zeolite can not only affect the hydrocracking performance of catalyst through acid-catalyzed reaction directly, but also through modulating the hydrogenation activity associated with the dispersion of metal components.
{"title":"Structure-performance relationship between zeolites properties and hydrocracking performance of tetralin over NiMo/Al2O3-Y catalysts: A machine-learning-assisted study","authors":"Wei Wang, Mingfeng Li, Yang Zhang, Kang Qin, Li Zhuang, Ping Yang, Hong Nie","doi":"10.1016/j.fuel.2025.134652","DOIUrl":"10.1016/j.fuel.2025.134652","url":null,"abstract":"<div><div>Oriented conversion of poly-aromatic hydrocarbons into benzene, toluene, and xylene (BTX) via selective hydrocracking is an effective way to upgrade low-quality fossil oils into high-valued products. An in-depth understanding of the structure-performance relationship is crucial to the further improvement of catalytic activity and selectivity. Zeolites are essential components of hydrocracking catalysts, of which pore structure and acid properties significantly influence the catalytic performance. However, the structure-performance relationship between them is multifactorial, and it’s quite difficult to be investigated using traditional experimental method which needs a large series of univariate samples. In this study, the multifactorial relationship was built with the help of machine learning modeling based on the dataset derived from the characterization of fifteen zeolite samples and the catalytic performance of the corresponding catalysts. Based on the model’s prediction, the effect of pore and acidity properties was quantitatively described. Mesopores were observed to have a great influence on conversion, while micropores have a great improvement in BTX selectivity. The amount of total acid was observed to have a significant effect on both conversion and selectivity. To get more insight into the intrinsic mechanism of the structure-performance relationship, more characterization of the spent catalysts was carried on. It was demonstrated that the properties of zeolite can not only affect the hydrocracking performance of catalyst through acid-catalyzed reaction directly, but also through modulating the hydrogenation activity associated with the dispersion of metal components.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"390 ","pages":"Article 134652"},"PeriodicalIF":6.7,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422683","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 : 2025-02-16DOI: 10.1016/j.fuel.2025.134716
Pengju Wei , Wei Wang , Yujing Chen , Mingming Zhang , Xuerong Zhou , Xiaozhen Chen , Qingquan Lin , Kaixuan Yang , Miao Zhang
ZSM-48 shows excellent performance in shape selective catalysis, especially in hydroisomerization reaction. However, adjusting the acidity of ZSM-48 and improving the synergy of acidic and metal sites are still major challenges in the application of ZSM-48 in hydroisomerization reaction. The dispersing Nb species on support can better utilize the active Nb species and regulate support surface acidity. In this paper, we develop a new route to regulate ZSM-48 surface acidity through Nb modified. The different Nb modified ZSM-48 is prepared under mild conditions and is characterized by physico-chemical characterization techniques such as XRD, N2 physisorption, NH3-TPD, SEM, Py-IR. Owing to its unique acidity, Nb-modified Pt/ZSM-48 exhibits better performance on the hexadecane hydroisomerization compared with Pt/ZSM-48. The selectivity of i-C16 can reach 87 wt% over Pt/20Nb/ZSM-48. The addition of Nb not only improves i-C16 selectivity but also enhances the stability of the catalyst. Our results provide a facile strategy to adjust the surface acidity of ZSM-48 as solid acids for catalytic applications.
{"title":"Nb-modified ZSM-48 as efficient catalysts for hexadecane hydroisomerization","authors":"Pengju Wei , Wei Wang , Yujing Chen , Mingming Zhang , Xuerong Zhou , Xiaozhen Chen , Qingquan Lin , Kaixuan Yang , Miao Zhang","doi":"10.1016/j.fuel.2025.134716","DOIUrl":"10.1016/j.fuel.2025.134716","url":null,"abstract":"<div><div>ZSM-48 shows excellent performance in shape selective catalysis, especially in hydroisomerization reaction. However, adjusting the acidity of ZSM-48 and improving the synergy of acidic and metal sites are still major challenges in the application of ZSM-48 in hydroisomerization reaction. The dispersing Nb species on support can better utilize the active Nb species and regulate support surface acidity. In this paper, we develop a new route to regulate ZSM-48 surface acidity through Nb modified. The different Nb modified ZSM-48 is prepared under mild conditions and is characterized by physico-chemical characterization techniques such as XRD, N<sub>2</sub> physisorption, NH<sub>3</sub>-TPD, SEM, Py-IR. Owing to its unique acidity, Nb-modified Pt/ZSM-48 exhibits better performance on the hexadecane hydroisomerization compared with Pt/ZSM-48. The selectivity of <em>i</em>-C<sub>16</sub> can reach 87 wt% over Pt/20Nb/ZSM-48. The addition of Nb not only improves <em>i</em>-C<sub>16</sub> selectivity but also enhances the stability of the catalyst. Our results provide a facile strategy to adjust the surface acidity of ZSM-48 as solid acids for catalytic applications.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"390 ","pages":"Article 134716"},"PeriodicalIF":6.7,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422635","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 : 2025-02-16DOI: 10.1016/j.fuel.2025.134717
Jinping Zhang , Jingchun Shen , Junyi Fang , Lei Chen , Chang’an Wang , Defu Che
Oxy-fuel co-combustion of semi-coke and biomass has emerged as a promising and environmentally sustainable avenue for reducing carbon emissions and realizing the resource utilization of solid waste. However, the underlying mechanisms of N-containing pollutants release and ash formation during co-combustion process remain somewhat unclear. Herein, the intricate characteristics of NOx formation and ash-related behavior during oxy-fuel co-combustion of semi-coke (SC) and three typical biomass (rice hull (RH), pine wood (PW) and walnut shell (WS)) were investigated based on the effects of various parameters, including blending ratio, temperature and atmosphere in this research. The results show that the minerals in biomass could efficiently inhibit the NOx formation through facilitating the reduction of NOx to N2, and increasing the biomass blending ratio would lead to a significant decrease of NOx emission. Additionally, the conversion of fuel-N to NOx demonstrated a consistent upward trend with increasing temperature from 900 °C to 1350 °C. Significant decreases of NOx are detected when adjusting the ratio of O2/CO2, with an optimal O2 concentration at 30 %. The biomass type and combustion atmosphere contributed greatly to chemical compositions and slagging propensity of the ash. In comparison with RH, PW and WS exhibited notably higher slagging propensity of ash under test conditions. Moreover, increasing the O2 concentration in O2/CO2 atmosphere would elevate the slagging propensity of ash by promoting the formation of calcium sulfate, which subsequently fostered the development of additional low-temperature eutectics. This study provides theoretical support for developing the fuel value of biomass and semi-coke, enabling collaborative disposal approaches and ultimately realizing carbon peak in thermal power industry.
{"title":"Study on NOx formation and ash characteristics during co-combustion of semi-coke and biomass under O2/CO2 conditions","authors":"Jinping Zhang , Jingchun Shen , Junyi Fang , Lei Chen , Chang’an Wang , Defu Che","doi":"10.1016/j.fuel.2025.134717","DOIUrl":"10.1016/j.fuel.2025.134717","url":null,"abstract":"<div><div>Oxy-fuel co-combustion of semi-coke and biomass has emerged as a promising and environmentally sustainable avenue for reducing carbon emissions and realizing the resource utilization of solid waste. However, the underlying mechanisms of N-containing pollutants release and ash formation during co-combustion process remain somewhat unclear. Herein, the intricate characteristics of NO<em><sub>x</sub></em> formation and ash-related behavior during oxy-fuel co-combustion of semi-coke (SC) and three typical biomass (rice hull (RH), pine wood (PW) and walnut shell (WS)) were investigated based on the effects of various parameters, including blending ratio, temperature and atmosphere in this research. The results show that the minerals in biomass could efficiently inhibit the NO<em><sub>x</sub></em> formation through facilitating the reduction of NO<em><sub>x</sub></em> to N<sub>2</sub>, and increasing the biomass blending ratio would lead to a significant decrease of NO<em><sub>x</sub></em> emission. Additionally, the conversion of fuel-N to NO<em><sub>x</sub></em> demonstrated a consistent upward trend with increasing temperature from 900 °C to 1350 °C. Significant decreases of NO<em><sub>x</sub></em> are detected when adjusting the ratio of O<sub>2</sub>/CO<sub>2</sub>, with an optimal O<sub>2</sub> concentration at 30 %. The biomass type and combustion atmosphere contributed greatly to chemical compositions and slagging propensity of the ash. In comparison with RH, PW and WS exhibited notably higher slagging propensity of ash under test conditions. Moreover, increasing the O<sub>2</sub> concentration in O<sub>2</sub>/CO<sub>2</sub> atmosphere would elevate the slagging propensity of ash by promoting the formation of calcium sulfate, which subsequently fostered the development of additional low-temperature eutectics. This study provides theoretical support for developing the fuel value of biomass and semi-coke, enabling collaborative disposal approaches and ultimately realizing carbon peak in thermal power industry.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"390 ","pages":"Article 134717"},"PeriodicalIF":6.7,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422688","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}
Zeolitic imidazolate frameworks (ZIFs) are rich in accessible and active Lewis acid-base sites and hierarchical pores, making them effective catalysts for the cycloaddition of CO2 to epoxides under mild conditions. In this study, a facile defect-engineering strategy using acid etching and ligand exchange was developed to convert three-dimensional ZIF-L into layered Br-ZIF-L with a tire-like surface, abundant active sites, and a structure optimized for efficient mass diffusion. This modification enabled the rapid cycloaddition of CO2 to propylene oxide under mild conditions (1 MPa and 100 °C for 2 h). The resulting cyclic carbonate was obtained in 92 % yield and 100 % selectivity. Additionally, Br-ZIF-L exhibited excellent chemical stability without a loss of catalytic activity after six consecutive cycles, highlighting its potential as a high-performance catalyst for CO2 conversion. The developed catalytic system exhibited a conversion rate of >90 % for five different substituted epoxides. This study introduces an efficient approach for synthesizing cyclic carbonates via CO2 fixation under mild conditions.
{"title":"CO2 fixation for the synthesis of cyclic carbonates using Br-ZIF-L with enriched defects","authors":"Zhengyu Yang, Jianmin Li, Yubin Wang, Mengyao Shi, Jide Wang, Changyan Guo","doi":"10.1016/j.fuel.2025.134701","DOIUrl":"10.1016/j.fuel.2025.134701","url":null,"abstract":"<div><div>Zeolitic imidazolate frameworks (ZIFs) are rich in accessible and active Lewis acid-base sites and hierarchical pores, making them effective catalysts for the cycloaddition of CO<sub>2</sub> to epoxides under mild conditions. In this study, a facile defect-engineering strategy using acid etching and ligand exchange was developed to convert three-dimensional ZIF-L into layered Br-ZIF-L with a tire-like surface, abundant active sites, and a structure optimized for efficient mass diffusion. This modification enabled the rapid cycloaddition of CO<sub>2</sub> to propylene oxide under mild conditions (1 MPa and 100 °C for 2 h). The resulting cyclic carbonate was obtained in 92 % yield and 100 % selectivity. Additionally, Br-ZIF-L exhibited excellent chemical stability without a loss of catalytic activity after six consecutive cycles, highlighting its potential as a high-performance catalyst for CO<sub>2</sub> conversion. The developed catalytic system exhibited a conversion rate of >90 % for five different substituted epoxides. This study introduces an efficient approach for synthesizing cyclic carbonates via CO<sub>2</sub> fixation under mild conditions.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"390 ","pages":"Article 134701"},"PeriodicalIF":6.7,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422687","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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