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An active learning workflow for predicting hydrogen atom adsorption energies on binary oxides based on local electronic transfer features

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Green Energy & Environment 2024年第10期9卷 1489-1496页

作者： Wenhao Jing Zihao Jiao Mengmeng Song Ya Liu Liejin Guo International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityShaanxi710049Xi'anChina Department of Energy and Power Engineering Shandong University of TechnologyZibo255000ShandongChina

Machine learning combined with density functional theory(DFT)enables rapid exploration of catalyst descriptors space such as adsorption energy,facilitating rapid and effective catalyst ***,there is still a lack of models for predicting adsorption energies on oxides,due to the complexity of elemental species and the ambiguous coordination *** work proposes an active learning workflow(LeNN)founded on local electronic transfer features(e)and the principle of coordinate rotation *** accurately characterizing the electron transfer to adsorption site atoms and their surrounding geometric structures,LeNN mitigates abrupt feature changes due to different element types and clarifies coordination *** a result,it enables the prediction of^(*)H adsorption energy on binary oxide surfaces with a mean absolute error(MAE)below 0.18 ***,we incorporate local coverage(θ_(l))and leverage neutral network ensemble to establish an active learning workflow,attaining a prediction MAE below 0.2 eV for 5419 multi-^(*)H adsorption *** findings validate the universality and capability of the proposed features in predicting^(*)H adsorption energy on binary oxide surfaces.

关键词： Machine learning Adsorption energy Binary oxide Electron transfer Active learning

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Construction of Z-Scheme In_(2)S_(3)-TiO_(2) for CO_(2) Reduction under Concentrated Natural Sunlight

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Chinese Journal of Structural Chemistry 2022年第1期41卷 34-39页

作者： Ya Liu Fangbo Yu Feng Wang Shengjie Bai Guiwei He State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

Producing chemical fuels from sunlight enables a sustainable way for energy *** various solar fuel generation approaches,photocatalytic CO_(2) reduction has the advantages of simple structure,mild reaction condition,directly reducing carbon emissions,***,most of the current photocatalytic systems can only absorb the UV-visible spectrum of solar ***,finding a way to utilize infrared light in the photocatalytic system has attracted more and more ***,a Z-scheme In_(2)S_(3)-TiO_(2) was constructed for CO_(2) reduction under concentrated natural *** infrared light was used to create a high-temperature environment for photocatalytic *** evolution rates of H2,CO,and C2H5OH reached 262.2,73.9,and 27.56μmol・h^(-1)・g^(-1),respectively,with an overall solar to fuels efficiency of 0.002%.This work provides a composite photocatalyst towards the utilization of full solar light spectrum,and could promote the research on photocatalytic CO_(2) reduction.

关键词： solar energy CO_(2) In_(2)S_(3) TiO_(2)

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High tension cyclic hydrocarbons synthesized from biomass-derived platform molecules for aviation fuels in two steps

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Green Energy & Environment 2023年第1期8卷 331-337页

作者： Zhanchao Li Yizhuo Wang Qing Li Liqing Xu Hong Wang Frontier Institute of Science and Technology Xi'an Jiaotong UniversityXi'an710054China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an710054China

Synthesizing ring structure aviation fuels from biomass-derived platform molecules is challenging,especially for bridged ring structure aviation fuels which are typically achieved from fossil-derived ***,we report the synthesis of a series of ring structure biofuels in two steps by a combination of a solvent-free Michael-cyclization reaction and a hydrodeoxygenation(HDO)reaction from lignocellulosederived 5,5-dimethyl-1,*** biofuels are obtained with high overall yields up to 90%,which exhibit high densities of 0.81 g cm^(-3)-0.88 g cm^(-3)and high volumetric neat heat of combustion(VNHOC)values of 36.0 MJ L^(-1)-38.6 MJ L^(-1).More importantly,bridged-ring structure hydrocarbons can also be achieved in two steps by a combination of a Robinson annulation reaction and an HDO reaction to afford the final products at high overall yields up to 90%.The bridged-ring structure products have comparable high densities and high VNHOC values to the best artificial fuel JP-10(0.94 g cm^(-3)and 39.6 MJ L^(-1)).The results demonstrate a promising way for the synthesis of high-density aviation fuels with different fuel properties at high yields.

关键词： Biofuels 5,5-Dimethyl-1,3-cyclohexanedione Solvent-free Michael-cyclization Robinson annulation Green reaction

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EXPERIMENTAL INVESTIGATION ON THE TRANSCRITICAL DYNAMIC CHARACTERISTICS OF WATER WALL FOR A SUPERCRITICAL CFB BOILER

EXPERIMENTAL INVESTIGATION ON THE TRANSCRITICAL DYNAMIC CHAR...

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ASME 2024 International Mechanical engineering Congress and Exposition, IMECE 2024

作者： Yang, Dong An, Ning Du, Xiaocheng Han, Lei Guo, Zerui Wei, Ziyu State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an China

ISBN: (纸本)9780791888667

When the boiler load varies, the operational parameters in the water wall will change, this process is called as dynamic process. Dynamic process presents unique flow and heat transfer phenomena within the water wall. To investigate the process, the research was conducted in a vertical upward smooth tube for a supercritical circulating fluidized bed (CFB) boiler. Experiments were conducted to explore the dynamic characteristics during transcritical pressure process. The results indicate that as system pressure decreases from 23 MPa to 21 MPa, the mass flux within the tube increases sharply, and the outlet fluid temperature decreases. Concurrently, a rapid rise in wall temperature was observed. As the inlet mass flux increases, the wall temperature eventually returns to the normal value. The dynamic heat transfer coefficients were calculated throughout the transcritical pressure process, revealing stages of heat transfer deterioration, subcooled boiling, and single-phase water heat transfer. In addition, experiments and numerical simulations were carried out to explore the dynamic characteristics at supercritical pressure. The dynamic response curves during the step process of heat flux and inlet enthalpy under supercritical pressure conditions were obtained. As the inlet enthalpy decreases, the system mass flux increases, and as the heat flux increases, the system mass flux decreases. And there is no rise in wall temperature during the dynamic response at supercritical pressure. Copyright © 2024 by ASME.

关键词： Water tube boilers

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Fast design of catalyst layer with optimal electrical-thermal-water performance for proton exchange membrane fuel cells

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Journal of Energy Chemistry 2023年第6期81卷 642-655,I0014页

作者： Jing Yao Yuchen Yang Xiongpo Hou Yikun Yang Fusheng Yang Zhen Wu Zaoxiao Zhang School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an 710049ShaanxiChina State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049ShaanxiChina

The catalyst layer(CL)is the core component in determining the electrical-thermal-water performance and cost of proton exchange membrane fuel cell(PEMFC).Systemic analysis and rapid prediction tools are required to improve the design efficiency of *** this study,a 3D multi-phase model integrated with the multi-level agglomerate model for CL is developed to describe the heat and mass transfer processes inside ***,a research framework combining the response surface method(RSM)and artificial neural network(ANN)model is proposed to conduct a quantitative analysis,and further a rapid and accurate *** the help of this research framework,the effects of CL composition on the electrical-thermal-water performance of PEMFC are *** results show that the mass of platinum,the mass of carbon,and the volume fraction of dry ionomer has a significant impact on the electrical-thermal-water *** the selected points,the sensitivity of the decision variables is ranked:volume fraction of dry ionomer>mass of platinum>mass of carbon>agglomerate *** particular,the sensitivity of the volume fraction of dry ionomer is over 50%at these ***,the comparison results show that the ANN model could implement a more rapid and accurate prediction than the RSM model based on the same sample *** in-depth study is beneficial to provide feasible guidance for high-performance CL design.

关键词： Catalyst layer Agglomerate model Sensitivity analysis Response surface Artificial neural network

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Influence of internal components on gas-solid flow characteristics in fluidized bed reactor for organic silicon monomer synthesis

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Particuology 2025年第1期96卷 294-311页

作者： Xiaohan Guo Fei Gao Xuehui Xu Jianbo Zhao Yinghou Li Guanghui Chen Pan Zhang Key Laboratory of Multiphase Flow Reaction and Separation Engineering of Shandong Province College of Chemical EngineeringQingdao University of Science and TechnologyQingdao266042China College of Electromechanical Engineering Qingdao University of Science and TechnologyQingdao266043China

Internal components play a crucial role in the synthesis of organic silicon monomer in gas-solid fluidized bed reactors (FBRs). Finger-tube (F-tube) and U-tube components are commonly utilized to control the temperature and ensure its homogeneity in FBRs, thereby guaranteeing a high selectivity of the target product. The main objective of this work is to better understand the influence of F-tube and U-tube on the hydrodynamics in FBRs. Computational fluid dynamics (CFD) combined with the particle image velocimetry (PIV) technique were employed to explore the flow characteristics. The numerical data were validated against the particle velocity using an image processing technique. The results revealed that the F-tube increases the bed voidage by 3.2% and reduces the pressure drop by 13.0%. While the U-tube increases the bed voidage by 2.1% and reduces the pressure drop by 11.2%. These internals improve fluidization by ensuring even particle distribution and enhancing intra-particle circulation compared to reactors without internals.

关键词： Internal components Gas-solid fluidized bed reactors Fluid dynamics Particle image velocimetry system

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Morphology Structure Evolution and Combustion Reactivity of Bituminous Char at Around Ash Melting Temperature

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Journal of Thermal Science 2022年第6期31卷 2189-2202页

作者： ZHANG Yandi YANG Huan WANG Bo HMShahzaib KHAN DUAN Xiaoli LIU Yinhe State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi'an Jiaotong UniversityXi'an 710049China

In slag tapping furnaces, char particles undergo a series of complex structural evolution before and after being captured by the liquid slag layer. The evolution results affect the carbon conversion rate and are affected by temperature fluctuations, especially in the ash melting temperature zone. Experimental study on structure evolution of bituminous char prepared at around ash melting temperature was carried out on a fixed bed. The morphology, specific surface area and mineral chemical composition were measured at different temperatures. Experimental results show that the number density and the size of ash droplets exuded on the char surface increased significantly with the increasing temperature. The ash specific surface area from gasification was slightly greater than that from combustion. The residual content of chloride in the char become 1% and the contents of Fe, K, Mg and Na decrease significantly during the pyrolysis process across the ash melting temperature zone. The diffraction intensity of oldhamite increase which indicates the reaction of carbon substrate with minerals during the evolution;the diffraction intensity of quartz dramatically decreases for the reason of anorthite generation. The ignition and burnout temperatures of char were found to increase and the combustion stability decreased with the increasing pyrolysis temperature.

关键词： coal char structure evolution carbothermal reaction combustion

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A RAPID WET-DRY state CONVERSION METHOD OF THE ULTRA-SUPERCRITICAL COAL-FIRED POWER PLANT BY OPTIMIZING THE RECIRCULATION WATER CONTROL STRATEGY

A RAPID WET-DRY STATE CONVERSION METHOD OF THE ULTRA-SUPERCR...

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ASME 2024 Power Conference, POWER 2024

作者： Liu, Zefeng Wang, Chaoyang Liu, Ming Yan, Junjie State Key Laboratory of Multiphase Flow Xi'an Jiaotong University Xi'an China

ISBN: (纸本)9780791888186

Switching between wet and dry states occurs frequently when the ultra-supercritical coal-fired power plant operates between 15% and 30% rated load. How to keep wet-state operation stable and switching between wet and dry states rapidly becomes an increasing concern. This study established a detailed dynamic model of a 660MW ultra-supercritical coal-fired power plant, including the boiler recirculation system in low-load. During the state conversion process, the boiler components' safe operation limitations were also considered as boundary conditions. Based on the developed model, the change trends of the key parameters were simulated when the wet-state operation and the energy distribution characteristics were analyzed during the conversion process. The results show that the temperature of separated recirculation water is greater than that of feedwater before converging, which has great potential to shorten the conversion time. The control scheme of recirculation water was revised by reconstructing the curve between the water level of the separator storage tank and the opening of the recirculation valve. The subcooling degree of feedwater entering the water wall decreased by regulating the recirculation of separated water on time and reasonably. The duration required for saturation decreased considerably with a constant water flow rate. By implementing the optimized control scheme, the operating mode switches from wet to dry in advance, and the corresponding unit load can decrease from 24.5% to 23.1% rated load. Based on the boiler components' safe operation, the state-conversion time can be shortened by 30% at most. This research will guide the low-load flexibility and safe operation optimization. Copyright © 2024 by ASME.

关键词： Fossil fuel power plants

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DYNAMIC MODELING AND PERFORMANCE EVALUATION OF THERMAL STORAGE TANK WITH PACKED BED OF PHASE CHANGE CAPSULES DURING CHARGING PROCESSES

DYNAMIC MODELING AND PERFORMANCE EVALUATION OF THERMAL STORA...

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ASME 2024 Power Conference, POWER 2024

作者： Wang, Chang Xu, Can Liu, Ming Yan, Junjie State Key Laboratory of Multiphase Flow Xi'an Jiaotong University Xi’an China

ISBN: (纸本)9780791888186

In order to address the issues of global energy crisis and environmental pollutions, renewable energies are being rapidly developed. However, solar energy and wind energy are intermittent, and energy storage should be applied to amid the imbalance between energy supply and demand sides. Thermal storage technology is an effective and potential way for large-scale and long-term energy storage, which can improve the stability and efficiency of power generation system driven by solar energy. To obtain the dynamic behaviors of thermal storage tank with packed-bed of phase change capsules, dynamic models of heat transfer fluid (HTF) and phase change capsules were developed based on a modified one-dimensional discrete concentric model. The governing equations were programed and validated. Then, the dynamic behaviors of the charging processes of thermal energy storage tank under variable operation conditions were simulated and analyzed. The effects of packed-bed characteristics, such as capsule diameter and porosity, on temperature distribution, thermal and exergy storage, energy and exergy efficiency during charging processes of thermal energy storage tank were studied. Moreover, influences of inlet temperature and mass flow rate variations of heat transfer fluid on charging behaviors was also studied to compare the dynamic variations of its energy and exergy efficiencies. These factors have affected the charging time, maximum heat storage capacity and efficiency to varying degrees. It is worth noting that the exergy efficiency of the charging process increases over time. The present work can provide insights into optimizing the operational strategies of thermal storage systems to achieve high charging efficiency. Copyright © 2024 by ASME.

关键词： Tanks (containers)

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THE OPERATIONAL STABILITY AND ENERGY EFFICIENCY OF COAL-FIRED POWER PLANT UNDER ULTRA-LOW POWER LOAD RATIO: FEEDWATER PREHEATING SYSTEM ISSUES

THE OPERATIONAL STABILITY AND ENERGY EFFICIENCY OF COAL-FIRE...

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ASME 2024 Power Conference, POWER 2024

作者： Du, Zeyu Liu, Ming Yan, Junjie State Key Laboratory of Multiphase Flow Xi'an Jiaotong University Xi'an China

ISBN: (纸本)9780791888186

The world energy supply continues to evolve and adapt to low carbon and sustainable sources due to energy shortage and environmental issues. As a result, the share of renewable energy sources in the energy mix sharply increases in many countries. However, wind and photovoltaic power is intermittent, and high penetration of renewable power poses high peak shaving pressure on the power system. Therefore, the peak shaving techniques for coal-fired power plant (CFPP) should be developed, aiming to decrease the adjustable minimal power load ratio. When the coal-fired power plant operates under low load ratio, it significantly deviates from the design condition, which will affect the operational safety and economic performances. In this study, the drainage obstruction issues of the feedwater preheating system are analyzed and addressed. Off-design analysis models of coal-fired power plant are developed. Simulation results show that the feedwater preheating system increases the net energy efficiency by 2.90%, 3.11%, 2.49% under 100%, 30% and 20% power load ratio conditions, respectively. The pressure difference between adjacent regenerative heaters (RH) decreases with the load ratio, thus increasing the risk of the drainage obstruction phenomenon. Then, schemes, including the RH’s switch-off, connecting the drainage pipe to deaerator (DRTR) or condenser, or installing the drainage pump (DP) in the drainage pipe are proposed and evaluated. Scheme A connects RH2’s and RH3’s drainage pipes to the DRTR, which can improve the unit’s operational stability and energy efficiency greatly when the drainage obstruction occurs in high-pressure feedwater preheating system. Scheme B connects RH7s and RH8’s drainage pipes to the condenser and Scheme C installs DPs in RH7s and RH8’s drainage pipelines. Scheme B and Scheme C can both enhance the operational stability of low-pressure feedwater preheating system under low load ratio condition. Scheme C have better energy efficiency performan

关键词： Preheating

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