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

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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Hydrocarbon generation reaction kinetics study on supercritical water conversion of centimeter sized medium and low maturity organic-rich shale

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Petroleum Science 2025年第5期22卷 2203-2214页

作者： Xie, Tian Zhao, Qiu-Yang Jin, Hui Wang, Ye-Chun Guo, Lie-Jin College of New Energy Xi'an Shiyou University Shaanxi Xi'an710065 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an710049 China

Accurate prediction of the composition of pyrolysis products is the prerequisite for achieving directional regulation of organic-rich shale pyrolysis and conversion products. In this paper, the classical segmented pyrolysis kinetics model and a new refined pyrolysis kinetics model were used to forecast the composition distribution of hydrocarbon generation products co-heated by supercritical water and medium and low maturity organic-rich shale. The prediction accuracy of the two reaction kinetics models for the composition of pyrolysis products of organic-rich shale was compared. The reaction path of hydrocarbon generation in centimeter sized organic-rich shale under the action of supercritical water was identified. The results show that the prediction accuracy of the classical segmented pyrolysis kinetics model was poor at the initial stage of the reaction, and gradually increased with increasing time. The prediction error can reach less than 25% when the reaction time was 12 h. The new refined model of reaction kinetics established is better than the classical reaction kinetics model in predicting the product distribution of pyrolysis oil and gas, and its prediction error is less than 14% in this paper. The reaction paths of hydrocarbon generation in centimeter sized organic-rich shale under supercritical water conversion mainly include organic-rich shale directly generates asphaltene and saturated hydrocarbon, asphaltene pyrolysis generates saturated hydrocarbon, aromatic hydrocarbon and resin, saturated hydrocarbon, aromatic hydrocarbon and resin polymerization generates asphaltene, and saturated hydrocarbon, resin and asphaltene generates gas. The reason for the difference of centimeter sized and millimeter sized medium and low maturity organic-rich shales hydrocarbon generation in supercritical water is that the increase of shale size promotes the reaction path of polymerization of saturated hydrocarbon and aromatic hydrocarbon to asphaltene. © 2025 The Author

关键词： Crystallization kinetics

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Experimental and Theoretical Study on CHF of a Ultra-Supercritical Circulating Fluidized Bed Boiler Water-Wall Tube at near-Critical Pressures

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Journal of Thermal Science 2023年第1期32卷 166-182页

作者： WANG Wenyu MA Zhan QING Hao NIE Chao YANG Haoyu BI Lingfeng YANG Dong PAN Wenxiao State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China Department of Mechanical Engineering University of Wisconsin-Madison1513 University AveMadisonWI 53706USA

The experimental and theoretical research on the critical heat flux(CHF)in a uniformly heated water-wall tube of the efficient ultra-supercritical circulating fluidized bed(USCFB)boiler has been *** particular,the experimental pressure varies from 18 MPa to 21 MPa,which is from 0.814Pcr–0.95Pcr(Pcr:critical pressure).The mass flux varies from 310 kg·m^(–2)·s^(–1)to 550 kg·m^(–2)·s^(–1).The inlet sub-cooling temperatures vary from 5°C to 10°*** material of the tube is *** experimental investigation,the near critical pressure CHF test data of water are *** find that the CHF mainly occurs when the vapor qualities are less than 0.4,and it occurs earlier(at lower vapor quality)when the pressure is closer to 22.115 MPa or the mass flux is *** the experimental data,a correlation function for the CHF is established via regression and machine *** established via machine learning greatly improved the regression *** study the CHF phenomenon mechanically,a theoretical model is established based on the near-surface bubble crowding model describing the DNB-type *** the development of the CHF model,the friction resistance coefficient is determined according to our test *** comparison with different experimental results,the near-surface bubble crowding model is well suited to describe DNB-type *** calculation results of the model can provide reference for the optimal design of the USCFB boiler.

关键词： circulating fluidized bed critical heat flux near-critical pressure bubble crowding machine learning

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Numerical prediction of spatio-temporal frosting patterns of curved surface considering varying working parameters

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Energy Storage and Saving 2023年第1期2卷 348-358页

作者： Xue Liu Xiaojun Dong Shaohang Yan Yu Hou Tianwei Lai State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an710049China

Accurate numerical prediction of frosting patterns is essential for the efficient layout and timing defrosting of heat exchangers under frosting *** this study,a numerical model is developed to predict the spatio-temporal frosting habits on curved surfaces in combination with the correlations of frost density and thermal *** the model,frost melting is *** verification,the frosting and heat transfer characteristics along the flow path are investigated under various structural and operating *** thickness along the path is mainly affected by the cooling surface temperature,while the heat and mass transfer rates are strongly correlated with the humidity *** proportions of latent heat and sensible heat are distributed more unevenly in parallel flow case than in counter flow *** deposition is facilitated by a smaller radius of curvature of the cooling *** uniform frosting characteristics along the path and smaller heat transfer obstruction are presented with a smaller length-to-height ratio of the flow path.

关键词： Frosting Numerical prediction Heat transfer Curved surface Varying parameter

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Alloy nanocrystals:Synthesis paradigms and implications

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Chinese Journal of Structural Chemistry 2023年第11期42卷 1-5页

作者： Zhaojun Liu Zerui Mu Chuanbo Gao State Key Laboratory of Multiphase Flow in Power Engineering Frontier Institute of Science and TechnologyXi'an Jiaotong UniversityXi'an710054China

*** Noble metal nanocrystals serve as exceptional catalysts across a wide spectrum of industrial processes[1].Moreover,there exists a substantial demand for noble metal catalysts in emerging clean-energy applications,such as water-splitting hydrogen production and fuel *** non-noble transition metals or main-group metals into noble metal nanocrystals can reduce the weight of noble metals in the catalysts,thus remarkably lowering the ***,alloy nanocrystals offer intriguing catalytic properties that surpass those of their monometallic counterparts,thanks to the charge transfer between the constituent components and the expansion or shrinkage of the lattice size[2].

关键词： alloy metals noble

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Review of spatial scale dispersion models (ATDMs) to simulate environmental dispersion and deposition of radionuclides and the overview of GIS coupling with dispersion models

International Journal of Advanced Nuclear Reactor Design and...

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International Journal of Advanced Nuclear Reactor Design and Technology 2024年第4期6卷 256-280页

作者： Muhammad, Hussaini Xuan, Wang Wang, Mingjun Su, Guanghui School of Nuclear Science and Technology Shanxi Key Laboratory of Advanced Nuclear Energy and Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Abuja Nigeria

Estimation of the radiological consequences including the calculation of radiation doses to the exposed population requires numerical evaluation of atmospheric radioactive releases from nuclear facilities under accidental scenarios for implementation of adequate protective and other response actions to prevent or minimize severe deterministic effects and reduce the probability of occurrence of stochastic effects. This paper reviews various state-of-the-art spatial scale atmospheric dispersion models, known as the ATDMs, designed to evaluate atmospheric transport, dispersion, and depositions of radionuclide emissions from release sources. The ATDMs (atmospheric transport, dispersion, and deposition models) reviewed in this paper are FLEXPART, CALPUFF, LADAS, RASCAL, RIMPUFF, and HotSpot. These ATDMs are increasingly applied to perform probabilistic radiological risk assessment, which is one of the IAEA safety requirements for site evaluation of new NPP, and the calculated doses can be used to establish EPZs, an underlying basis of emergency preparedness. The numerical approaches, modeling methodology, advantages, limitations, scope of applications, and research investigations performed using these models in radiological and other environmental impact assessments within their scope of applications are presented. GIS has been widely recognized as a technique applied to aid the modeling of pollutant dispersion and visualization of model outputs in a spatial context, among other benefits. In nuclear accident consequence evaluation, spatial data provides key information such as accident location, range of radiological contamination, population density, etc, which are very important. This demonstrates the high significance of GIS-ATDMs coupling. Therefore, an overview of the coupling of dispersion models with GIS is also highlighted. © 2025 Xi'an Jiaotong University

关键词： Risk assessment

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MIXED DISCONTINUOUS GALERKIN METHOD FOR QUASI-NEWTONIAN STOKES flowS

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Journal of Computational Mathematics 2024年第3期42卷 885-910页

作者： Yanxia Qian Fei Wang Wenjing Yan School of Mathematics and Statistics Xi'an Jiaotong UniversityXi'an 710049China School of Mathematics and Statistics&State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

In this paper,we introduce and analyze an augmented mixed discontinuous Galerkin(MDG)method for a class of quasi-Newtonian Stokes *** the mixed formulation,the unknowns are strain rate,stress and velocity,which are approximated by a discontinuous piecewise polynomial triplet ■for k≥***,the discontinuous piecewise polynomial function spaces for the field of strain rate and the stress field are designed to be *** addition,the pressure is easily recovered through simple *** the benefit of the analysis,we enrich the MDG scheme with the constitutive equation relating the stress and the strain rate,so that the well-posedness of the augmented formulation is obtained by a nonlinear functional *** k≥0,we get the optimal convergence order for the stress in broken ■(div)-norm and velocity in L^(2)-***,the error estimates of the strain rate and the stress in-norm,and the pressure in L^(2)-norm are optimal under certain ***,several numerical examples are given to show the performance of the augmented MDG method and verify the theoretical *** evidence is provided to show that the orders of convergence are sharp.

关键词： Quasi-Newtonian fows Mixed discontinuous Galerkin method Symmetric strain rate Symmetric stress Optimal convergence orders

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Experimental study on the thermochemical reduction of supercritical CO2by guaiacol 8

Experimental study on the thermochemical reduction of superc...

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8th International Conference on Smart and Sustainable Technologies, SpliTech 2023

作者： Wei, Yimeng Kuanibieke, Jiadela Jin, Hui Xi'an Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering China

ISBN: (纸本)9789532901283

The continuous growth of CO2 emissions is one of the global problems facing humanity, and how to convert and exploit the stock of CO2 has become an urgent issue. Biomass as an activity of CO2 thermal reduction medium has become the focus of human attention in general. Supercritical CO2 (SCCO2) has the advantages of near-liquid density and high solubility, which can further strengthen the reduction process (T≥31.26, P≥72.9 atm). This paper described a SCCO2 reduction method of guaiacol on an intermittent Kettle Reactor to investigate the effects of reaction temperature (400-700), residence time (5-20 min) and reactant concentration (4 wt%-16wt%) on the three-phase products. The experimental results indicated that the carbon gasification efficiency (CE) and hydrogen gasification efficiency (HE) were 43.7% and 56.7%, respectively, when the carbon dioxide consumption reached 16.15 mol/kg. As the temperature increased, the consumption of carbon dioxide increased and the concentration of reactants increased with opposite results. © 2023 University of Split, FESB.

关键词： Carbon dioxide

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Defect-engineered WO_(x)/ZnIn_(2)S_(4)Z-scheme heterojunction boosting photocatalytic H_(2)production via photothermal coupling

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Journal of Energy Chemistry 2025年第4期103卷 9-18页

作者： Biao Wang Chunyang Zhang Shidong Zhao Shujian Wang Feng Liu Kejian Lu Yitao Si Maochang Liu International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringSchool of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an 710049ShaanxiChina School of Chemistry and Chemical Engineering Southeast UniversityNanjing 211189JiangsuChina Suzhou Academy of Xi’an Jiaotong University Suzhou 215123JiangsuChina

Recent interest in photocatalytic water splitting has intensified the demand in the development of photocatalysts capable of harnessing the full *** study introduces a novel WO_(x)/ZnIn_(2)S_(4)Zscheme heterojunction,prepared by depositing ZnIn_(2)S_(4)(ZIS)nanosheets onto WO_(x)nanorods,enabling efficient photothermal-coupled photocatalytic H_(2)*** success relies on the engineered oxygen vacancies within WO_(x)nanorods,which not only confer excellent photothermal properties lowering the reaction barrier but also create defect levels in WO_(x)facilitating Z-scheme electron transfer from these levels to the valence band of ***,the optimized WO_(x)/ZIS heterojunction exhibits a remarkable H_(2)evolution rate of 33.91 mmol h^(-1)g^(-1)with an apparent quantum efficiency of 23.6%at 400 *** study provides a new strategy for developing efficient Z-scheme heterojunctions with broadspectrum solar hydrogen production capabilities.

关键词： Defect-engineered Z-scheme heterojunction Photocatalytic H2evolution Photothermal coupling

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BiOI晶体缺陷工程提升光催化CO2到C2产物转化性能（英文）

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Science China Materials 2025年第5期68卷 1561-1569页

作者：黄富霞刘一菲王峰刘亚郭烈锦 International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong University

BiOI材料在光催化CO2还原领域展现出巨大潜力,但其较弱的CO2的活化能力与较差的载流子分离效率严重制约了光催化转化效率.本研究通过构建富含丰富晶体缺陷的BiOI基光催化剂有效地提高了其光催化性能.结合X射线衍射、拉曼、和高分辨透射... 详细信息

BiOI材料在光催化CO2还原领域展现出巨大潜力,但其较弱的CO2的活化能力与较差的载流子分离效率严重制约了光催化转化效率.本研究通过构建富含丰富晶体缺陷的BiOI基光催化剂有效地提高了其光催化性能.结合X射线衍射、拉曼、和高分辨透射电子显微镜表征,证实了BiOI-LD和BiOI-TC催化剂中分别存在晶格畸变和孪晶结构缺陷.紫外-可见光谱、微孔与化学吸附分析,以及光致发光光谱表征结果表明,晶体缺陷的引入显著增强了光催化剂的光吸收能力、CO2吸附能力、载流子传输效率及寿命.电子顺磁共振光谱进一步证实BiOI-TC中超氧自由基的生成量显著提升,表明晶体缺陷构筑有效增强了催化剂表面反应活性.因此, BiOI-TC催化剂实现了6.2μmol g-1h-1的CH3CH2OH生成速率,且选择性达到100%.通过原位FTIR研究识别了生成CH3CH2OH的关键中间体（*CO、*COCO、*CHO和*CH2）,并揭示BiOI-LD中C2H6的生成与*CH3中间体的形成密切相关.

关键词： photocatalysis CO2 reduction BiOI crystal defects CH3CH2OH C2H6

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