3D printing technology enhances the combustion characteristics of hybrid rocket fuels by enabling complex geometries. However, improvements in regression rates and energy properties of monotonous 3D printed fuels have...3D printing technology enhances the combustion characteristics of hybrid rocket fuels by enabling complex geometries. However, improvements in regression rates and energy properties of monotonous 3D printed fuels have been limited. This study explores the impact of poly(vinylidene fluoride) and polydopamine-coated aluminum particles on the thermal and combustion properties of 3D printed hybrid rocket fuels. Physical self-assembly and anti-solvent methods were employed for constructing composite μAl particles. Characterization using SEM, XRD, XPS, FTIR, and μCT revealed a core-shell structure and homogeneous elemental distribution. Thermal analysis showed that PVDF coatings significantly increased the heat of combustion for aluminum particles, with maximum enhancement observed in μAl@PDA@PVDF(denoted as μAl@PF) at 6.20 k J/g. Subsequently, 3D printed fuels with varying pure and composite μAl particle contents were prepared using 3D printing. Combustion tests indicated higher regression rates for Al@PF/Resin composites compared to pure resin, positively correlating with particle content. The fluorocarbon-alumina reaction during the combustion stage intensified Al particle combustion, reducing residue size. A comprehensive model based on experiments provides insights into the combustion process of PDA and PVDF-coated droplets. This study advances the design of 3D-printed hybrid rocket fuels, offering strategies to improve regression rates and energy release, crucial for enhancing solid fuel performance for hybrid propulsion.展开更多
The internal pressure within fission gas bubbles(FGBs)in irradiated nuclear fuels drives mechanical interactions with the surrounding fuel skeleton.To investigate the micromechanical stress fields in irradiated nuclea...The internal pressure within fission gas bubbles(FGBs)in irradiated nuclear fuels drives mechanical interactions with the surrounding fuel skeleton.To investigate the micromechanical stress fields in irradiated nuclear fuels containing pressurized FGBs,a mechanical constitutive model for the equivalent solid of FGBs was developed and validated.This model was based on the modified Van der Waals equation,incorporating the effects of surface tension.Using this model,the micromechanical fields in irradiated U-10Mo fuels with randomly distributed FGBs were calculated during uniaxial tensile testing via the finite element(FE)method.The macroscopic elastic constants of the irradiated U-10Mo fuels were then derived using homogenization theory,and the influences of bubble pressure,bubble size,and porosity on these constants were examined.Results show that adjacent FGBs exhibit mechanical interactions,which leads to distinct stress concentrations in the surrounding fuel skeleton.The macroscopic elastic constants of irradiated U-10Mo fuels decrease with increasing the macroscopic porosity,which can be quantitatively described by the Mori-Tanaka model.In contrast,bubble pressure and size have negligible effects on these constants.展开更多
Hydrothermal liquefaction technology is an effective method for the resource utilization and energy conversion of biomass under the dual-carbon context,facilitating the conversion of biomass into liquid fuels and high...Hydrothermal liquefaction technology is an effective method for the resource utilization and energy conversion of biomass under the dual-carbon context,facilitating the conversion of biomass into liquid fuels and high-value chemicals.This paper reviews the latest advancements in the production of liquid fuels and chemicals from biomass hydrothermal liquefaction.It briefly introduces the effects of different types of biomass,such as organic waste,lignocellulosic materials,and algae,on the conversion efficiency and product yield during hydrothermal liquefaction.The specific mechanisms of solvent and catalyst systems in the hydrothermal liquefaction process are analyzed in detail.Compared to water and organic solvents,the biphasic solvent system yields higher concentrations of furan platform compounds,and the addition of an appropriate amount of NaCl to the solvent significantly enhances product yield.Homogeneous catalysts exhibit advantages in reaction rate and selectivity but are limited by high costs and difficulties in separation and recovery.In contrast,heterogeneous catalysts possess good separability and regeneration capabilities and can operate under high-temperature conditions,but their mass transfer efficiency and deactivation issues may affect catalytic performance.The direct hydrothermal catalytic conversion of biomass is also discussed for the efficient production of chemicals and fuels such as hexanol,ethylene glycol,lactic acid,and C5/C6 liquid alkanes.Finally,the advantages and current challenges of producing liquid fuels and chemicals from biomass hydrothermal liquefaction are thoroughly analyzed,along with potential future research directions.展开更多
Biodiesel is a clean and renewable energy,and it is an effective measure to optimize engine combustion fueled with biodiesel to meet the increasingly strict toxic and CO_(2) emission regulations of internal combustion...Biodiesel is a clean and renewable energy,and it is an effective measure to optimize engine combustion fueled with biodiesel to meet the increasingly strict toxic and CO_(2) emission regulations of internal combustion engines.A suitable-scale chemical kinetic mechanism is very crucial for the accurate and rapid prediction of engine combustion and emissions.However,most previous researchers developed the mechanism of blend fuels through the separate simplification and merging of the reduced mechanisms of diesel and biodiesel rather than considering their cross-reaction.In this study,a new reduced chemical reaction kinetics mechanism of diesel and biodiesel was constructed through the adoption of directed relationship graph (DRG),directed relationship graph with error propagation,and full-species sensitivity analysis (FSSA).N-heptane and methyl decanoate (MD) were selected as surrogates of traditional diesel and biodiesel,respectively.In this mechanism,the interactions between the intermediate products of both fuels were considered based on the cross-reaction theory.Reaction pathways were revealed,and the key species involved in the oxidation of n-heptane and MD were identified through sensitivity analyses.The reduced mechanism of n-heptane/MD consisting of 288 species and 800 reactions was developed and sufficiently verified by published experimental data.Prediction maps of ignition delay time were established at a wide range of parameter matrices (temperature from 600 to 1 700 K,pressure from 10 bar to 80 bar,equivalence ratio from 0.5 to 1.5) and different substitution ratios to identify the occurrence regions of the crossreaction.Concentration and sensitivity analyses were then conducted to further investigate the effects of cross-reactions.The results indicate temperature as the primary factor causing cross-reactivity.In addition,the reduced mechanism with cross-reactions was more accurate than that without cross-reactions.At 700–1 000 K,the cross-reactions inhibited the consumption of n-heptane/MD,which resulted in a prolonged ignition delay time.At this point,the elementary reaction,NC_(7)H_(16)+OH<=>C_(7)H_(15)-2+H_(2)O,played a dominant role in fuel consumption.Specifically,the contribution of the MD consumption reaction to ignition decreased,and the increased generation time of OH,HO_(2),and H_(2)O_(2) was directly responsible for the increased ignition delay.展开更多
A promising way to address environmental problems caused by plastic waste is through its upcycling into renewable energy and resources.With annual production reaching millions of tons,one of the most widely single-use...A promising way to address environmental problems caused by plastic waste is through its upcycling into renewable energy and resources.With annual production reaching millions of tons,one of the most widely single-use daily plastics,polyethylene terephthalate(PET),has recently been investigated in terms of chemical recycling to reduce its environmental impact and generate renewable fuels.This study introduces an innovative electrochemical method for the specific conversion of PET hydrolysate into highvalue compounds utilizing CoCuO_(x)@MXene/NF catalyst.Our findings revealed that the electrocatalyst was capable of facilitating the conversion of water into hydrogen(H_(2)),while simultaneously oxidizing ethylene glycol(EG),obtained from PET plastic waste hydrolysis,into formate with a high selectivity and lower initial potential compared to water oxidation.Notably,the exceptional performance was attributed to the synergistic interfacial electronic coupling effect between CoCuO_(x)and MXene,which results in a low overpotential(1.24 V@10 mA cm^(-2))and a high yield of formate product(87.6%).In addition,the electrolyzer could be operated using solar energy panel for upcycling of PET to formic acid and hydrogen fuels by using CoCuO_(x)@MXene catalyst.展开更多
Metal-support interactions and hydrogen spillover effects in heterogeneous catalysts play a crucial role in aromatic hydrogenation reactions;however,these effects are limited by the metal dispersion on the catalyst an...Metal-support interactions and hydrogen spillover effects in heterogeneous catalysts play a crucial role in aromatic hydrogenation reactions;however,these effects are limited by the metal dispersion on the catalyst and the number of acceptable H*receptors.This study prepares highly dispersed Ni nanoparticles(NPs)catalysts on a Beta substrate via precursor structure topology transformation.In contrast to traditional support materials,the coordination and electronic structure changes between the Ni NPs and the support were achieved,further optimizing the active interface sites and enhancing hydrogen activation and hydrogenation performance.Additionally,the-OH groups at the strong acid sites in zeolite effectively intensified the hydrogen spillover effect as receptors for H^(*)migration and anchoring,accelerating the hydrogenation rate of aromatic rings.Under solvent-free conditions,this catalyst was used for the hydrogenation reaction of aromatic-rich oils,directly producing a C_(8)-C_(14)branched cycloalkanes mixture with an aromatic conversion rate of>99%.The cycloalkanes mixture produced by this method features high density(0.92 g/mL)and a low freezing point(<-60℃),making it suitable for use as high-density aviation fuel or as an additive to enhance the volumetric heat value of conventional aviation fuels in practical applications.展开更多
Electrochemical CO_(2)reduction has been considered a promising approach to neutralizing the global CO_(2)level.As an intriguing technique,metal-CO_(2)battery devices can not only capture CO_(2)into valuable carbonace...Electrochemical CO_(2)reduction has been considered a promising approach to neutralizing the global CO_(2)level.As an intriguing technique,metal-CO_(2)battery devices can not only capture CO_(2)into valuable carbonaceous chem-icals and reduce the CO_(2)concentration in the atmosphere but enable energy conversion.Among metal-CO_(2)batteries,aqueous Zn–CO_(2)batteries,especially rechargeable systems,exhibit flexible CO_(2)electrochemistry in terms of multi-carbon chemicals,which are gaseous or water-soluble,in favor of rechargeability and cycling durability of aqueous battery systems.Despite the increasing number of publications on Zn–CO_(2)batteries in the past three years,this field is still in its beginning stage and facing many challenges considering the capability of CO_(2)fixation and battery performance.Herein,we present a timely and overall summary of the recent progress in Zn–CO_(2)batteries,including fundamental mechanisms,affecting factors on electrochemical performance,catalyst cathodes,and electrolytes(catholytes and anolytes).Besides,we assess the application potential of Zn–CO_(2)batteries and compare this with those of alkali metal-CO_(2)batteries based on CO_(2)fixation and battery perfor-mance.Finally,we point out some current challenges for the further development of Zn–CO_(2)batteries and put forward perspectives of the research directions for practical applications of Zn–CO_(2)batteries in the future.展开更多
The research investigated application effects of alcohol-based fuels in in- tensive curing. The results showed that alcohol-based fuels allow flexible adjustment of temperature and heat supplying. What＇s more, in tre...The research investigated application effects of alcohol-based fuels in in- tensive curing. The results showed that alcohol-based fuels allow flexible adjustment of temperature and heat supplying. What＇s more, in treatment A, the cured tobac- cos are softer and brighter, with more oil content and higher proportion of first-class tobaccos. Per leaf weight increased by 0.13 g and output value per kang （a heat- able brick bed） deducting energy cost grew by 188.66 yuan. In addition, the con- tents of reducing sugar and potassium enhanced within the ranges of high-quality tobacco, and chemical components are more coordinated.展开更多
Metal-Supported Solid Oxide Fuel Cells(MS-SOFCs)hold significant potential for driving the energy transition.These electrochemical devices represent the most advanced generation of Solid Oxide Fuel Cell(SOFCs)and can ...Metal-Supported Solid Oxide Fuel Cells(MS-SOFCs)hold significant potential for driving the energy transition.These electrochemical devices represent the most advanced generation of Solid Oxide Fuel Cell(SOFCs)and can pave the way for mass production and wider adoption than Proton Exchange Membrane Fuel Cells(PEMFCs)due to their fuel flexibility,higher power density and the absence of noble metals in the fabrication processes.This review examines the state-of-the-art of SOFCs and MS-SOFCs,presenting perspectives and research directions for these key technological devices,highlighting novel materials,techniques,architectures,devices,and degradation mechanisms to address current challenges and future opportunities.Techniques such as infiltration/impregnation,ex-solution catalyst synthesis,and the use of a pre-catalytic reformer layer are discussed as their impact on efficiency and prolonged activity.These concepts are also described and connected with well-dispersed nano particles,hindrance of coarsening,and an increased number of Triple Phase Boundaries(TPBs).This review also describes the synergistic use of reformers with MS-SOFCs to compose solutions in energy generation from readily available fuels.Lastly,the End-of-Life(EoL),recycling,and life-cycle assessments(LCAs)of the Fuel Cell Hybrid Electric Vehicles(FCHEVs)were discussed.LCAs comparing Fuel Cell Electric Vehicles(FCEVs)equipped with(PEMFCs)and FCHEVs equipped with MS-SOFCs,both powered with hydrogen(H_(2))generated by different routes were compared.This review aims to provide valuable insights into these key technological devices,emphasizing the importance of robust research and development to enhance performance and lifespan while reducing costs and environmental impact.展开更多
Sustainable aviation fuel(SAF)production from biomass and biowaste streams is an attractive option for decarbonizing the aviation sector,one of the most-difficult-to-electrify transportation sectors.Despite ongoing co...Sustainable aviation fuel(SAF)production from biomass and biowaste streams is an attractive option for decarbonizing the aviation sector,one of the most-difficult-to-electrify transportation sectors.Despite ongoing commercialization efforts using ASTM-certified pathways(e.g.,lipid conversion,Fischer-Tropsch synthesis),production capacities are still inadequate due to limited feedstock supply and high production costs.New conversion technologies that utilize lignocellulosic feedstocks are needed to meet these challenges and satisfy the rapidly growing market.Combining bio-and chemo-catalytic approaches can leverage advantages from both methods,i.e.,high product selectivity via biological conversion,and the capability to build C-C chains more efficiently via chemical catalysis.Herein,conversion routes,catalysis,and processes for such pathways are discussed,while key challenges and meaningful R&D opportunities are identified to guide future research activities in the space.Bio-and chemo-catalytic conversion primarily utilize the carbohydrate fraction of lignocellulose,leaving lignin as a waste product.This makes lignin conversion to SAF critical in order to utilize whole biomass,thereby lowering overall production costs while maximizing carbon efficiencies.Thus,lignin valorization strategies are also reviewed herein with vital research areas identified,such as facile lignin depolymerization approaches,highly integrated conversion systems,novel process configurations,and catalysts for the selective cleavage of aryl C-O bonds.The potential efficiency improvements available via integrated conversion steps,such as combined biological and chemo-catalytic routes,along with the use of different parallel pathways,are identified as key to producing all components of a cost-effective,100%SAF.展开更多
Accurate and robust detection of wax appearance(a medium-to high-molecular-weight component of crude oil)is crucial for the efficient operation of hydrocarbon transportation.The wax appearance temperature(WAT)is the l...Accurate and robust detection of wax appearance(a medium-to high-molecular-weight component of crude oil)is crucial for the efficient operation of hydrocarbon transportation.The wax appearance temperature(WAT)is the lowest temperature at which the wax begins to form.When crude oil cools to its WAT,wax crystals precipitate,forming deposits on pipelines as the solubility limit is reached.Therefore,WAT is a crucial quality assurance parameter,especially when dealing with modern fuel oil blends.In this study,we use machine learning via MATLAB’s Bioinformatics Toolbox to predict the WAT of marine fuel samples by correlating near-infrared spectral data with laboratory-measured values.The dataset provided by Intertek PLC-a total quality assurance provider of inspection,testing,and certification services-includes industrial data that is imbalanced,with a higher proportion of high-WAT samples compared to low-WAT samples.The objective is to predict marine fuel oil blends with unusually high WAT values(>35℃)without relying on time-consuming and irregular laboratory-based measurements.The results demonstrate that the developed model,based on the one-class support vector machine(OCSVM)algorithm,achieved a Recall of 96,accurately predicting 96%of fuel samples with WAT>35℃.For standard binary classification,the Recall was 85.7.The trained OCSVM model is expected to facilitate rapid and well-informed decision-making for logistics and storage when choosing fuel oils.展开更多
Direct coal liquefaction products offer a considerable quantity of cycloalkanes, which are the valuable candidates for making the high energy density fuels. The creation of such fuels depends on designing molecular st...Direct coal liquefaction products offer a considerable quantity of cycloalkanes, which are the valuable candidates for making the high energy density fuels. The creation of such fuels depends on designing molecular structures and calculating their properties, which can be expedited with computer-aided techniques. In this study, a dataset containing 367 fuel molecules was constructed based on the analysis of direct coal liquefied oil. Three convolutional neural network property prediction models have been created based on molecular structure-physical and chemical property data from the library. All the models have good fitting ability with R2 values above 0.97. Then, a variational autoencoder generation model has been established using the molecular structures from the library, focusing on the structure of saturated cycloalkanes. The structure-property prediction model was then applied to the newly generated molecules, assessing their density, volumetric calorific value, and melting point. As a result, 70000 novel molecular structures were generated, and 25 molecular structures meeting the criteria for high energy density fuels were identified. The established variational autoencoder model in this study effectively assimilates the structural information from the sample set and autonomously generates novel high energy density fuels, which is difficult to achieve in traditional experimental methods.展开更多
Designing Fischer-Tropsch synthesis(FTS)catalysts to selectively produce liquid hydrocarbon fuels is a crucial challenge.Herein,we selectively introduced Co nanoparticles(NPs)into the micropores and mesopores of an or...Designing Fischer-Tropsch synthesis(FTS)catalysts to selectively produce liquid hydrocarbon fuels is a crucial challenge.Herein,we selectively introduced Co nanoparticles(NPs)into the micropores and mesopores of an ordered mesoporous MFI zeolite(OMMZ)through impregnation,which controlled the carbon number distribution in the FTS products by tuning the position of catalytic active sites in differently sized pores.The Co precursors coordinated by acetate with a size of 9.4×4.2×2.5Åand by 2,2'-bipyridine with a size of 9.5×8.7×7.9Å,smaller and larger than the micropores(ca.5.5Å)of MFI,made the Co species incorporated in OMMZ's micropores and mesopores,respectively.The carbon number products synthesized with the Co NPs confined in mesopores were larger than that in micropores.The high jet and diesel selectivities of 66.5%and 65.3%were achieved with Co NPs confined in micropores and mesopores of less acidic Na-type OMMZ,respectively.Gasoline and jet selectivities of 76.7%and 70.8%were achieved with Co NPs confined in micropores and mesopores of H-type OMMZ with Brönsted acid sites,respectively.A series of characterizations revealed that the selective production of diesel and jet fuels was due to the C-C cleavage suppressing of heavier hydrocarbons by the Co NPs located in mesopores.展开更多
Achieving carbon neutrality is urgent due to the critical issue of climate change.To reach this goal,the development of new,breakthrough technologies is necessary and urgent.One such technology involves efficient carb...Achieving carbon neutrality is urgent due to the critical issue of climate change.To reach this goal,the development of new,breakthrough technologies is necessary and urgent.One such technology involves efficient carbon capture and its conversion into useful chemicals or fuels.However,achieving considerable amounts of efficiency in this field is a very challenging task.Even in natural photosynthesis occurring in plant leaves,the CO_(2)conversion efficiency into hydrocarbons cannot exceed a value of 1%.Nevertheless,recently few reports show comparable higher efficiency in CO_(2)to gaseous products such as carbon monoxide(CO),but it is hard to find selective liquid fuel products with a high value of solar to liquid fuel conversion efficiency.Herein,a NiFe-assisted hybrid composite dark cathode is employed for the selective production of solar-to-liquid fuels,in conjunction with a BiVO4 photoanode.This process results in the generation of significant amounts of formaldehyde,ethanol,and methanol selectively.The primary objective of this study is to design and optimize a novel photoelectrochemical(PEC)system to produce solar-to-liquid fuels selectively.This study shows the enhancement of the solar-to-fuel conversion efficiency over 1.5%by employing a hybrid composite cathode composed of NiFe-assisted reduced graphene oxide(rGO),poly(4-vinyl)pyridine(PVP),and Nafion.展开更多
After short introducing the crucial role of e‐fuels to meet net‐zero emissions targets,this perspective paper discusses the differences between reactive catalysis(electro‐,photo‐and plasma‐catalysis,with focus on...After short introducing the crucial role of e‐fuels to meet net‐zero emissions targets,this perspective paper discusses the differences between reactive catalysis(electro‐,photo‐and plasma‐catalysis,with focus on the first for conciseness)and thermal catalysis used at most.The main point is to evidence that to progress in producing e‐fuels,the gap is not in terms of scaling‐up and pilot testing,but rather in the fundamental needs to turn the current approach and methodologies to develop reactive catalysis,including from a mechanistic perspective,to go beyond the current methods largely derived from thermal catalysis.Developing thus new fundamental bases to understand reactive catalysis is the challenge to accelerate the progress in this area to enable the potential role towards a sustainable net‐zero emissions future.Some novel aspects are highlighted,but the general aim is rather to stimulate discussion in rethinking catalysis from an alternative perspective.展开更多
Fuel moisture content is an important variable for forest fires because it affects fuel ignition and fire behavior. In order to accurately predict fuel ignition potential, fuel moisture content must be assessed by eva...Fuel moisture content is an important variable for forest fires because it affects fuel ignition and fire behavior. In order to accurately predict fuel ignition potential, fuel moisture content must be assessed by evaluating fire spread, fireline intensity and fuel consumption.Our objective here is to model moisture content of surface fuels in normally stocked Calabrian pine(Pinus brutia Ten.) stands in relation to weather conditions, namely temperature, relative humidity, and wind speed in the Mugla province of Turkey. All surface fuels were categorized according to diameter classes and fuel types. Six fuel categories were defined: these were 0–0.3, 0.3–0.6, and0.6–1 cm diameter classes, and cone, surface litter, and duff. Plastic containers 15 9 20 cm in size with 1 9 1 mm mesh size were used. Samples were taken from 09:00 to19:00 h and weighed every 2 h with 0.01 g precision for10 days in August. At the end of the study, samples were taken to the laboratory, oven-dried at 105 °C for 24 h and weighed to obtain fuel-moisture contents. Weather measurements were taken from a fully automated weather station set up at the study site prior to the study. Correlation and regression analyses were carried out and models were developed to predict fuel moisture contents for desorption and adsorption phase for each fuel type categories. Practical fuel moisture prediction models were developed for dry period. Models were developed that performed well with reasonable accuracy, explaining up to 92 and 95.6%of the variability in fuel-moisture contents for desorption and adsorption phases, respectively. Validation of the models were conducted using an independent data set and known fuel moisture prediction models. The predictive power of the models was satisfactory with mean absolute error values being 1.48 and 1.02 for desorption and adsorption as compared to the 2.05 and 1.60 values for the Van Wagner's hourly litter moisture content prediction model. Results obtained in this study will be invaluable for fire management planning and modeling.展开更多
The chemical utilization of CO_2 is a crucial step for the recycling of carbon resource. In recent years, the study on the conversion of CO_2 into a wide variety of C_(2+) important chemicals and fuels has received co...The chemical utilization of CO_2 is a crucial step for the recycling of carbon resource. In recent years, the study on the conversion of CO_2 into a wide variety of C_(2+) important chemicals and fuels has received considerable attention as an emerging technology. Since CO_2 is thermodynamically stable and kinetically inert, the effective activation of CO_2 molecule for the selective transformation to target products still remains a challenge. The welldesigned CO_2 reduction route and efficient catalyst system has imposed the feasibility of CO_2 conversion into C_(2+) chemicals and fuels. In this paper, we have reviewed the recent advances on chemical conversion of CO_2 into C_(2+) chemicals and fuels with wide practical applications, including important alcohols, acetic acid, dimethyl ether, olefins and gasoline. In particular, the synthetic routes for C\\C coupling and carbon chain growth, multifunctional catalyst design and reaction mechanisms are exclusively emphasized.展开更多
基金funded by the National Natural Science Foundation of China(Grant No.06101213)the National Natural Science Foundation of China(Grant No.22105160).
文摘3D printing technology enhances the combustion characteristics of hybrid rocket fuels by enabling complex geometries. However, improvements in regression rates and energy properties of monotonous 3D printed fuels have been limited. This study explores the impact of poly(vinylidene fluoride) and polydopamine-coated aluminum particles on the thermal and combustion properties of 3D printed hybrid rocket fuels. Physical self-assembly and anti-solvent methods were employed for constructing composite μAl particles. Characterization using SEM, XRD, XPS, FTIR, and μCT revealed a core-shell structure and homogeneous elemental distribution. Thermal analysis showed that PVDF coatings significantly increased the heat of combustion for aluminum particles, with maximum enhancement observed in μAl@PDA@PVDF(denoted as μAl@PF) at 6.20 k J/g. Subsequently, 3D printed fuels with varying pure and composite μAl particle contents were prepared using 3D printing. Combustion tests indicated higher regression rates for Al@PF/Resin composites compared to pure resin, positively correlating with particle content. The fluorocarbon-alumina reaction during the combustion stage intensified Al particle combustion, reducing residue size. A comprehensive model based on experiments provides insights into the combustion process of PDA and PVDF-coated droplets. This study advances the design of 3D-printed hybrid rocket fuels, offering strategies to improve regression rates and energy release, crucial for enhancing solid fuel performance for hybrid propulsion.
基金National Natural Science Foundation of China(12135008,12132005)。
文摘The internal pressure within fission gas bubbles(FGBs)in irradiated nuclear fuels drives mechanical interactions with the surrounding fuel skeleton.To investigate the micromechanical stress fields in irradiated nuclear fuels containing pressurized FGBs,a mechanical constitutive model for the equivalent solid of FGBs was developed and validated.This model was based on the modified Van der Waals equation,incorporating the effects of surface tension.Using this model,the micromechanical fields in irradiated U-10Mo fuels with randomly distributed FGBs were calculated during uniaxial tensile testing via the finite element(FE)method.The macroscopic elastic constants of the irradiated U-10Mo fuels were then derived using homogenization theory,and the influences of bubble pressure,bubble size,and porosity on these constants were examined.Results show that adjacent FGBs exhibit mechanical interactions,which leads to distinct stress concentrations in the surrounding fuel skeleton.The macroscopic elastic constants of irradiated U-10Mo fuels decrease with increasing the macroscopic porosity,which can be quantitatively described by the Mori-Tanaka model.In contrast,bubble pressure and size have negligible effects on these constants.
基金supported by the National Natural Science Foundation of China(Grant Nos.52306125,52176095)Natural Science Research Project of Colleges and Universities in Anhui Province(Nos.2022AH050311,KJ2020ZD29)Anhui Provincial Natural Science Foundation(No.2008085J25).
文摘Hydrothermal liquefaction technology is an effective method for the resource utilization and energy conversion of biomass under the dual-carbon context,facilitating the conversion of biomass into liquid fuels and high-value chemicals.This paper reviews the latest advancements in the production of liquid fuels and chemicals from biomass hydrothermal liquefaction.It briefly introduces the effects of different types of biomass,such as organic waste,lignocellulosic materials,and algae,on the conversion efficiency and product yield during hydrothermal liquefaction.The specific mechanisms of solvent and catalyst systems in the hydrothermal liquefaction process are analyzed in detail.Compared to water and organic solvents,the biphasic solvent system yields higher concentrations of furan platform compounds,and the addition of an appropriate amount of NaCl to the solvent significantly enhances product yield.Homogeneous catalysts exhibit advantages in reaction rate and selectivity but are limited by high costs and difficulties in separation and recovery.In contrast,heterogeneous catalysts possess good separability and regeneration capabilities and can operate under high-temperature conditions,but their mass transfer efficiency and deactivation issues may affect catalytic performance.The direct hydrothermal catalytic conversion of biomass is also discussed for the efficient production of chemicals and fuels such as hexanol,ethylene glycol,lactic acid,and C5/C6 liquid alkanes.Finally,the advantages and current challenges of producing liquid fuels and chemicals from biomass hydrothermal liquefaction are thoroughly analyzed,along with potential future research directions.
基金Supported by the National Natural Science Foundation of China (Grant No. 52171298)the National Foreign Experts Program (G2023180006L)+1 种基金the Natural Science Foundation of Heilongjiang Province of China (Grant No. ZD2019E003)the Fundamental Research Funds for the Central Universities (Grant No. 3072022TS0303)。
文摘Biodiesel is a clean and renewable energy,and it is an effective measure to optimize engine combustion fueled with biodiesel to meet the increasingly strict toxic and CO_(2) emission regulations of internal combustion engines.A suitable-scale chemical kinetic mechanism is very crucial for the accurate and rapid prediction of engine combustion and emissions.However,most previous researchers developed the mechanism of blend fuels through the separate simplification and merging of the reduced mechanisms of diesel and biodiesel rather than considering their cross-reaction.In this study,a new reduced chemical reaction kinetics mechanism of diesel and biodiesel was constructed through the adoption of directed relationship graph (DRG),directed relationship graph with error propagation,and full-species sensitivity analysis (FSSA).N-heptane and methyl decanoate (MD) were selected as surrogates of traditional diesel and biodiesel,respectively.In this mechanism,the interactions between the intermediate products of both fuels were considered based on the cross-reaction theory.Reaction pathways were revealed,and the key species involved in the oxidation of n-heptane and MD were identified through sensitivity analyses.The reduced mechanism of n-heptane/MD consisting of 288 species and 800 reactions was developed and sufficiently verified by published experimental data.Prediction maps of ignition delay time were established at a wide range of parameter matrices (temperature from 600 to 1 700 K,pressure from 10 bar to 80 bar,equivalence ratio from 0.5 to 1.5) and different substitution ratios to identify the occurrence regions of the crossreaction.Concentration and sensitivity analyses were then conducted to further investigate the effects of cross-reactions.The results indicate temperature as the primary factor causing cross-reactivity.In addition,the reduced mechanism with cross-reactions was more accurate than that without cross-reactions.At 700–1 000 K,the cross-reactions inhibited the consumption of n-heptane/MD,which resulted in a prolonged ignition delay time.At this point,the elementary reaction,NC_(7)H_(16)+OH<=>C_(7)H_(15)-2+H_(2)O,played a dominant role in fuel consumption.Specifically,the contribution of the MD consumption reaction to ignition decreased,and the increased generation time of OH,HO_(2),and H_(2)O_(2) was directly responsible for the increased ignition delay.
基金The financial assistance provided by the Centre National de la Recherche Scientifique(CNRS),the University of Lille,the Hautsde-France region,and the CPER“Wavetech”are acknowledgedthe Chinese government for the China Scholarship Council(CSC)fellowship。
文摘A promising way to address environmental problems caused by plastic waste is through its upcycling into renewable energy and resources.With annual production reaching millions of tons,one of the most widely single-use daily plastics,polyethylene terephthalate(PET),has recently been investigated in terms of chemical recycling to reduce its environmental impact and generate renewable fuels.This study introduces an innovative electrochemical method for the specific conversion of PET hydrolysate into highvalue compounds utilizing CoCuO_(x)@MXene/NF catalyst.Our findings revealed that the electrocatalyst was capable of facilitating the conversion of water into hydrogen(H_(2)),while simultaneously oxidizing ethylene glycol(EG),obtained from PET plastic waste hydrolysis,into formate with a high selectivity and lower initial potential compared to water oxidation.Notably,the exceptional performance was attributed to the synergistic interfacial electronic coupling effect between CoCuO_(x)and MXene,which results in a low overpotential(1.24 V@10 mA cm^(-2))and a high yield of formate product(87.6%).In addition,the electrolyzer could be operated using solar energy panel for upcycling of PET to formic acid and hydrogen fuels by using CoCuO_(x)@MXene catalyst.
基金financially supported by the National Natural Science Foundation of China(Grant 22278439,21776313)the Shandong Province Higher Education Youth Innovation Technology Support Program(Grant 2022KJ074)。
文摘Metal-support interactions and hydrogen spillover effects in heterogeneous catalysts play a crucial role in aromatic hydrogenation reactions;however,these effects are limited by the metal dispersion on the catalyst and the number of acceptable H*receptors.This study prepares highly dispersed Ni nanoparticles(NPs)catalysts on a Beta substrate via precursor structure topology transformation.In contrast to traditional support materials,the coordination and electronic structure changes between the Ni NPs and the support were achieved,further optimizing the active interface sites and enhancing hydrogen activation and hydrogenation performance.Additionally,the-OH groups at the strong acid sites in zeolite effectively intensified the hydrogen spillover effect as receptors for H^(*)migration and anchoring,accelerating the hydrogenation rate of aromatic rings.Under solvent-free conditions,this catalyst was used for the hydrogenation reaction of aromatic-rich oils,directly producing a C_(8)-C_(14)branched cycloalkanes mixture with an aromatic conversion rate of>99%.The cycloalkanes mixture produced by this method features high density(0.92 g/mL)and a low freezing point(<-60℃),making it suitable for use as high-density aviation fuel or as an additive to enhance the volumetric heat value of conventional aviation fuels in practical applications.
基金supported by the National Key R&D Program of China under Project 2019YFA0705104GRF under Project CityU11212920.
文摘Electrochemical CO_(2)reduction has been considered a promising approach to neutralizing the global CO_(2)level.As an intriguing technique,metal-CO_(2)battery devices can not only capture CO_(2)into valuable carbonaceous chem-icals and reduce the CO_(2)concentration in the atmosphere but enable energy conversion.Among metal-CO_(2)batteries,aqueous Zn–CO_(2)batteries,especially rechargeable systems,exhibit flexible CO_(2)electrochemistry in terms of multi-carbon chemicals,which are gaseous or water-soluble,in favor of rechargeability and cycling durability of aqueous battery systems.Despite the increasing number of publications on Zn–CO_(2)batteries in the past three years,this field is still in its beginning stage and facing many challenges considering the capability of CO_(2)fixation and battery performance.Herein,we present a timely and overall summary of the recent progress in Zn–CO_(2)batteries,including fundamental mechanisms,affecting factors on electrochemical performance,catalyst cathodes,and electrolytes(catholytes and anolytes).Besides,we assess the application potential of Zn–CO_(2)batteries and compare this with those of alkali metal-CO_(2)batteries based on CO_(2)fixation and battery perfor-mance.Finally,we point out some current challenges for the further development of Zn–CO_(2)batteries and put forward perspectives of the research directions for practical applications of Zn–CO_(2)batteries in the future.
基金Supported by Longyan Tobacco Company S&T Project(2014-18)~~
文摘The research investigated application effects of alcohol-based fuels in in- tensive curing. The results showed that alcohol-based fuels allow flexible adjustment of temperature and heat supplying. What＇s more, in treatment A, the cured tobac- cos are softer and brighter, with more oil content and higher proportion of first-class tobaccos. Per leaf weight increased by 0.13 g and output value per kang （a heat- able brick bed） deducting energy cost grew by 188.66 yuan. In addition, the con- tents of reducing sugar and potassium enhanced within the ranges of high-quality tobacco, and chemical components are more coordinated.
基金the Fundacao de Amparo à Pesquisa do Estado de Sao Paulo(FAPESP,2022/02235-4,2017/11958-1,2017/11986-5,2014/02163-7)Fundacao de Apoio da UFMG(FUNDEP,27192-36,01-P-38465/2023)Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq,405675/2022-4,56405643/2022-5,302180/2022-2,306870/2021-5)。
文摘Metal-Supported Solid Oxide Fuel Cells(MS-SOFCs)hold significant potential for driving the energy transition.These electrochemical devices represent the most advanced generation of Solid Oxide Fuel Cell(SOFCs)and can pave the way for mass production and wider adoption than Proton Exchange Membrane Fuel Cells(PEMFCs)due to their fuel flexibility,higher power density and the absence of noble metals in the fabrication processes.This review examines the state-of-the-art of SOFCs and MS-SOFCs,presenting perspectives and research directions for these key technological devices,highlighting novel materials,techniques,architectures,devices,and degradation mechanisms to address current challenges and future opportunities.Techniques such as infiltration/impregnation,ex-solution catalyst synthesis,and the use of a pre-catalytic reformer layer are discussed as their impact on efficiency and prolonged activity.These concepts are also described and connected with well-dispersed nano particles,hindrance of coarsening,and an increased number of Triple Phase Boundaries(TPBs).This review also describes the synergistic use of reformers with MS-SOFCs to compose solutions in energy generation from readily available fuels.Lastly,the End-of-Life(EoL),recycling,and life-cycle assessments(LCAs)of the Fuel Cell Hybrid Electric Vehicles(FCHEVs)were discussed.LCAs comparing Fuel Cell Electric Vehicles(FCEVs)equipped with(PEMFCs)and FCHEVs equipped with MS-SOFCs,both powered with hydrogen(H_(2))generated by different routes were compared.This review aims to provide valuable insights into these key technological devices,emphasizing the importance of robust research and development to enhance performance and lifespan while reducing costs and environmental impact.
基金supported by the Center for Bioenergy Innovation(CBI)supported by the Office of Biological and Environmental Research in the DOE Office of Science and led by Oak Ridge National Laboratory.Oak Ridge National Laboratory is managed by UT-Battelle,LLC for the US DOE under Contract Number DE-AC05-00OR22725+2 种基金authored in part by the Na-tional Renewable Energy Laboratory,operated by Alliance for Sustainable Energy,LLC,for the U.S.Department of Energy(DOE)under Contract No.DE-LC-000L054provided by the U.S.Department of Energy(DOE),Office of Energy Efficiency and Renewable Energy(EERE),and Bioenergy Technologies Office(BETO)at the Pacific Northwest National Laboratory(PNNL)under Contract No.DE-AC05-76RL01830supported by Laboratory Directed Research and Development(LDRD)funding from Argonne National Laboratory,provided by the Director,Office of Science,of the U.S.Department of Energy under Contract No.DE-AC02-06CH11357。
文摘Sustainable aviation fuel(SAF)production from biomass and biowaste streams is an attractive option for decarbonizing the aviation sector,one of the most-difficult-to-electrify transportation sectors.Despite ongoing commercialization efforts using ASTM-certified pathways(e.g.,lipid conversion,Fischer-Tropsch synthesis),production capacities are still inadequate due to limited feedstock supply and high production costs.New conversion technologies that utilize lignocellulosic feedstocks are needed to meet these challenges and satisfy the rapidly growing market.Combining bio-and chemo-catalytic approaches can leverage advantages from both methods,i.e.,high product selectivity via biological conversion,and the capability to build C-C chains more efficiently via chemical catalysis.Herein,conversion routes,catalysis,and processes for such pathways are discussed,while key challenges and meaningful R&D opportunities are identified to guide future research activities in the space.Bio-and chemo-catalytic conversion primarily utilize the carbohydrate fraction of lignocellulose,leaving lignin as a waste product.This makes lignin conversion to SAF critical in order to utilize whole biomass,thereby lowering overall production costs while maximizing carbon efficiencies.Thus,lignin valorization strategies are also reviewed herein with vital research areas identified,such as facile lignin depolymerization approaches,highly integrated conversion systems,novel process configurations,and catalysts for the selective cleavage of aryl C-O bonds.The potential efficiency improvements available via integrated conversion steps,such as combined biological and chemo-catalytic routes,along with the use of different parallel pathways,are identified as key to producing all components of a cost-effective,100%SAF.
基金Newcastle University and EPSRC(Grant No.2020/21 DTP:ref.EP/T517914/1).
文摘Accurate and robust detection of wax appearance(a medium-to high-molecular-weight component of crude oil)is crucial for the efficient operation of hydrocarbon transportation.The wax appearance temperature(WAT)is the lowest temperature at which the wax begins to form.When crude oil cools to its WAT,wax crystals precipitate,forming deposits on pipelines as the solubility limit is reached.Therefore,WAT is a crucial quality assurance parameter,especially when dealing with modern fuel oil blends.In this study,we use machine learning via MATLAB’s Bioinformatics Toolbox to predict the WAT of marine fuel samples by correlating near-infrared spectral data with laboratory-measured values.The dataset provided by Intertek PLC-a total quality assurance provider of inspection,testing,and certification services-includes industrial data that is imbalanced,with a higher proportion of high-WAT samples compared to low-WAT samples.The objective is to predict marine fuel oil blends with unusually high WAT values(>35℃)without relying on time-consuming and irregular laboratory-based measurements.The results demonstrate that the developed model,based on the one-class support vector machine(OCSVM)algorithm,achieved a Recall of 96,accurately predicting 96%of fuel samples with WAT>35℃.For standard binary classification,the Recall was 85.7.The trained OCSVM model is expected to facilitate rapid and well-informed decision-making for logistics and storage when choosing fuel oils.
基金the National Natural Science Foundation of China(22178243 and 22038008).
文摘Direct coal liquefaction products offer a considerable quantity of cycloalkanes, which are the valuable candidates for making the high energy density fuels. The creation of such fuels depends on designing molecular structures and calculating their properties, which can be expedited with computer-aided techniques. In this study, a dataset containing 367 fuel molecules was constructed based on the analysis of direct coal liquefied oil. Three convolutional neural network property prediction models have been created based on molecular structure-physical and chemical property data from the library. All the models have good fitting ability with R2 values above 0.97. Then, a variational autoencoder generation model has been established using the molecular structures from the library, focusing on the structure of saturated cycloalkanes. The structure-property prediction model was then applied to the newly generated molecules, assessing their density, volumetric calorific value, and melting point. As a result, 70000 novel molecular structures were generated, and 25 molecular structures meeting the criteria for high energy density fuels were identified. The established variational autoencoder model in this study effectively assimilates the structural information from the sample set and autonomously generates novel high energy density fuels, which is difficult to achieve in traditional experimental methods.
文摘Designing Fischer-Tropsch synthesis(FTS)catalysts to selectively produce liquid hydrocarbon fuels is a crucial challenge.Herein,we selectively introduced Co nanoparticles(NPs)into the micropores and mesopores of an ordered mesoporous MFI zeolite(OMMZ)through impregnation,which controlled the carbon number distribution in the FTS products by tuning the position of catalytic active sites in differently sized pores.The Co precursors coordinated by acetate with a size of 9.4×4.2×2.5Åand by 2,2'-bipyridine with a size of 9.5×8.7×7.9Å,smaller and larger than the micropores(ca.5.5Å)of MFI,made the Co species incorporated in OMMZ's micropores and mesopores,respectively.The carbon number products synthesized with the Co NPs confined in mesopores were larger than that in micropores.The high jet and diesel selectivities of 66.5%and 65.3%were achieved with Co NPs confined in micropores and mesopores of less acidic Na-type OMMZ,respectively.Gasoline and jet selectivities of 76.7%and 70.8%were achieved with Co NPs confined in micropores and mesopores of H-type OMMZ with Brönsted acid sites,respectively.A series of characterizations revealed that the selective production of diesel and jet fuels was due to the C-C cleavage suppressing of heavier hydrocarbons by the Co NPs located in mesopores.
基金financially supported by the Leader Project at the Korea Institute of Energy Technology(KENTECH)for Environmental and Climate Technology,funded by the Ministry of Science and ICT through the National Research Foundation of Korea(No.2020R1A3B3079715)The large-scale CO_(2)RR for future work is in process and is financially supported by the Korea Evaluation Institute of Industrial Technology(Alchemist Project,NTIS-2410005253,20018904)through the Ministry of Trade,Industry and Energy,Koreasupported by the National Supercomputing Center with supercomputing resources,including technical support(KSC-2022-CRE-0286).
文摘Achieving carbon neutrality is urgent due to the critical issue of climate change.To reach this goal,the development of new,breakthrough technologies is necessary and urgent.One such technology involves efficient carbon capture and its conversion into useful chemicals or fuels.However,achieving considerable amounts of efficiency in this field is a very challenging task.Even in natural photosynthesis occurring in plant leaves,the CO_(2)conversion efficiency into hydrocarbons cannot exceed a value of 1%.Nevertheless,recently few reports show comparable higher efficiency in CO_(2)to gaseous products such as carbon monoxide(CO),but it is hard to find selective liquid fuel products with a high value of solar to liquid fuel conversion efficiency.Herein,a NiFe-assisted hybrid composite dark cathode is employed for the selective production of solar-to-liquid fuels,in conjunction with a BiVO4 photoanode.This process results in the generation of significant amounts of formaldehyde,ethanol,and methanol selectively.The primary objective of this study is to design and optimize a novel photoelectrochemical(PEC)system to produce solar-to-liquid fuels selectively.This study shows the enhancement of the solar-to-fuel conversion efficiency over 1.5%by employing a hybrid composite cathode composed of NiFe-assisted reduced graphene oxide(rGO),poly(4-vinyl)pyridine(PVP),and Nafion.
基金supported by EU with ERC Synergy SCOPE(Surface-Confined Fast-modulated Plasma for Process and Energy Intensification in Small Molecules Conversion,810182)ProjectItalian MUR by PRIN 2017 Projects MULTI-e (Multielectron Transfer for the Conversion of Small Moleculesan Enabling Technology for the Chemical Use of Renewable Energy,20179337R7)CO_(2) ONLY (CO_(2) as Only Source of Carbons for Monomers and PolymersA Step Forwards Circular economy) Project,017WR2LRS
文摘After short introducing the crucial role of e‐fuels to meet net‐zero emissions targets,this perspective paper discusses the differences between reactive catalysis(electro‐,photo‐and plasma‐catalysis,with focus on the first for conciseness)and thermal catalysis used at most.The main point is to evidence that to progress in producing e‐fuels,the gap is not in terms of scaling‐up and pilot testing,but rather in the fundamental needs to turn the current approach and methodologies to develop reactive catalysis,including from a mechanistic perspective,to go beyond the current methods largely derived from thermal catalysis.Developing thus new fundamental bases to understand reactive catalysis is the challenge to accelerate the progress in this area to enable the potential role towards a sustainable net‐zero emissions future.Some novel aspects are highlighted,but the general aim is rather to stimulate discussion in rethinking catalysis from an alternative perspective.
基金supported by The Scientific and Technological Research Council of Turkey(TUBITAK),Project No:TOVAG–112O809
文摘Fuel moisture content is an important variable for forest fires because it affects fuel ignition and fire behavior. In order to accurately predict fuel ignition potential, fuel moisture content must be assessed by evaluating fire spread, fireline intensity and fuel consumption.Our objective here is to model moisture content of surface fuels in normally stocked Calabrian pine(Pinus brutia Ten.) stands in relation to weather conditions, namely temperature, relative humidity, and wind speed in the Mugla province of Turkey. All surface fuels were categorized according to diameter classes and fuel types. Six fuel categories were defined: these were 0–0.3, 0.3–0.6, and0.6–1 cm diameter classes, and cone, surface litter, and duff. Plastic containers 15 9 20 cm in size with 1 9 1 mm mesh size were used. Samples were taken from 09:00 to19:00 h and weighed every 2 h with 0.01 g precision for10 days in August. At the end of the study, samples were taken to the laboratory, oven-dried at 105 °C for 24 h and weighed to obtain fuel-moisture contents. Weather measurements were taken from a fully automated weather station set up at the study site prior to the study. Correlation and regression analyses were carried out and models were developed to predict fuel moisture contents for desorption and adsorption phase for each fuel type categories. Practical fuel moisture prediction models were developed for dry period. Models were developed that performed well with reasonable accuracy, explaining up to 92 and 95.6%of the variability in fuel-moisture contents for desorption and adsorption phases, respectively. Validation of the models were conducted using an independent data set and known fuel moisture prediction models. The predictive power of the models was satisfactory with mean absolute error values being 1.48 and 1.02 for desorption and adsorption as compared to the 2.05 and 1.60 values for the Van Wagner's hourly litter moisture content prediction model. Results obtained in this study will be invaluable for fire management planning and modeling.
基金Supported by the National Natural Science Foundation of China(21576272,21476244)"Transformational Technologies for Clean Energy and Demonstration"+2 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA21030600)the project from Jiangsu Collaborative Innovation Center for Ecological Building Materials and Environmental Protection Equipment(YCXT201607)Youth Innovation Promotion Association(2016046)of CAS
文摘The chemical utilization of CO_2 is a crucial step for the recycling of carbon resource. In recent years, the study on the conversion of CO_2 into a wide variety of C_(2+) important chemicals and fuels has received considerable attention as an emerging technology. Since CO_2 is thermodynamically stable and kinetically inert, the effective activation of CO_2 molecule for the selective transformation to target products still remains a challenge. The welldesigned CO_2 reduction route and efficient catalyst system has imposed the feasibility of CO_2 conversion into C_(2+) chemicals and fuels. In this paper, we have reviewed the recent advances on chemical conversion of CO_2 into C_(2+) chemicals and fuels with wide practical applications, including important alcohols, acetic acid, dimethyl ether, olefins and gasoline. In particular, the synthetic routes for C\\C coupling and carbon chain growth, multifunctional catalyst design and reaction mechanisms are exclusively emphasized.
