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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

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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Quantitative detection of alkali metal Na based on laser-induced breakdown spectroscopy technology

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Meitan Xuebao/Journal of the China Coal Society 2025年第4期50卷 2262-2270页

作者： Shen, Sijie Li, Chi Zhou, Wangzheng Wang, Zhenzhen Yan, Junjie Hou, Zongyu Wang, Zhe Deguchi, Yoshihiro School of Energy and Power Engineering Xi'an Jiaotong University Xi'an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China State Key Laboratory of Power System Operation and Control Tsinghua University Beijing100084 China Institute for Carbon Neutrality Tsinghua University Beijing100084 China Department of Energy and Power Engineering Tsinghua University Beijing100084 China Shanxi Research Institute for Clean Energy Tsinghua University Taiyuan030032 China Graduate School of Technology Industrial and Social Sciences Tokushima University Tokushima770-8506 Japan

The alkali metal compounds released from high alkali fuels such as low-quality coal during thermal utilization can affect the normal operation of thermal equipment. Therefore, rapid online detection of alkali metal content in low-quality coal is of great significance for controlling alkali metal release during combustion. The alkali metal Na element is used as the detection object, and the mixed samples of graphite and sodium chloride powder with different ratios are used as experimental samples. The influencing factors of measuring Na element in samples using laser induced breakdown spectroscopy (LIBS) technology are studied. The impact of two signal strength calculation methods on signal stability is compared. The influence of experimental parameters on signal strength and signal-to-noise ratio is analyzed. The quantitative calculation models for Na element have been established. Research has shown that the characteristic spectral lines of Na element, Na I 588.995 nm and Na I 589.592 nm, are suitable as the main analytical spectral lines. Using the area intensity of the dual line characteristic spectral lines of Na element as the signal intensity can effectively improve signal stability. When the laser energy is 60 mJ and the delay time is 1 000 ns, the relative standard deviation of spectral signal intensity is low and the signal-to-noise ratio is high. The quantitative calculation models are established using traditional calibration method, partial least squares (PLS) method, and support vector machine (SVR) with spectral signal intensity as the input and Na element addition in the sample as the output. The accuracy of each model is compared and analyzed. The results indicate that the PLS model may exhibit overfitting when the sample size is small and the input quantity is large. The fitting accuracy of the SVR model is 0.978 3, the root mean square percentage error of the training set is 13.42%, and the root mean square percentage error of the test set is 13.51

关键词： Sodium chloride

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Proposal and performance analysis on thermal energy storage systems with live and reheat steam as heat sources to co-enhance the operational flexibility and efficiency of coal-fired power plants

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Journal of Energy Storage 2025年 127卷

作者： Yang, Shuokang Liu, Ming Zhang, Kezhen Liu, Miaomiao Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Xi'an Thermal Power Research Institute Co. Ltd. Xi'an710054 China

The high penetration of intermittent renewable power threatens the steady operation of the power grid, and the operational flexibility of schedulable power plants should be enhanced. Thermal energy storage (TES) emerges as a promising technique to enhance the operational flexibility of coal-fired power plants (CFPPs). In this study, molten salt thermal storage systems utilizing live and reheat steam as heat sources were proposed, and the steam ejectors were integrated to recover the residual pressure of exhausted steam from the TES system to co-enhance the operational flexibility and energy efficiency of coal-fired power plants. Two TES system schemes, i.e., the scheme D1 storing medium-temperature heat to heat feedwater afterwards, and the scheme D2 storing high-temperature heat to generate steam afterwards, were designed. Then, simulation models were developed, and performance indicators were defined. Results indicate that the operational flexibility of the coal-fired power plant can be enhanced by the integration of the TES system, and the adjustable minimum load ratio can be decreased from 30 % to 17.71 % and 17.83 % for the schemes D1 and D2, respectively. When the steam ejectors are integrated, the equivalent round-trip efficiency can be increased by 1.60 % and 2.43 % for schemes D1 and D2, respectively. The scheme D2 shows a higher equivalent round-trip efficiency of 46.69 %, surpassing the scheme D1. © 2025 Elsevier Ltd

关键词： Fossil fuel power plants

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Temperature dependence photoluminescence properties of ZnSe-based core-shell quantum dots

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Optics Express 2025年第11期33卷 22588-22597页

作者： Zhang, Tingting Ma, Qing Li, Qingping Huang, Lanting Feng, Yuqiong Duan, Hongwei Chen, Xinlei Li, Qinghua Jin, Xiao Bai, Jinke Xu, Bing Key Laboratory of Environmentally Friendly Functional Materials and Devices School of Physics Science and Technology Lingnan Normal University Guangdong Zhanjiang524048 China School of Energy and Power Engineering Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Department of Materials and Chemical Engineering Taiyuan University Taiyuan030032 China

Heavy metal-free ZnSe-based core-shell quantum dots (QDs) are promising emitting material for achieving violet-blue luminescence. Investigating the temperature-dependent variations in the photoluminescence (PL) properties of ZnSe-based QDs will enhance our understanding of the intrinsic factors that influence their diverse luminescence characteristics. Here we select the optimally synthesized ZnSe core QDs with three diameters (4.1, 5.2, and 8.3 nm) and ZnSe/ZnS core-shell QDs to study their temperature-dependent photoluminescence properties. As the sample temperature is increased, the PL intensity decreases, the emission energy redshifts, and the spectral become broader. We observe a reduction in the exciton-longitudinal optical (LO)-phonon coupling constant from 21.7 meV to 16.1 meV as the diameter of ZnSe core QDs increased from 4.1 nm to 8.3 nm. This decrease is associated with a narrower homogeneous broadening of the emission spectrum. Besides, the epitaxial growth of a ZnS wide bandgap shells onto the ZnSe core QDs can effectively isolate the photogenerated excitons away from the inorganic-organic interface, thus reducing the PL peak width and increasing the exciton binding energy of the QDs. Our research provides a valuable addition to the existing studies on the photoluminescence properties of ZnSe-based core-shell QDs. © 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

关键词： Atomic emission spectroscopy

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Evaporation of sub-millimeter flying dinitrogen tetroxide droplet under high temperature and pressure: Experimental measurement and theoretical modeling

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Chinese Journal of Aeronautics 2025年第5期 82-93页

作者： Lihan FEI Wu ZHU Yuyuan ZHANG Peng ZHANG Zuohua HUANG Chenglong TANG State Key Laboratory of Multiphase Flow and Power Engineering Xi'an Jiaotong University Department of Mechanical Engineering City University of Hong Kong

The evaporation behaviors are crucial for the flame location estimation in liquid rocketengines. This work, for the first time, experimentally reports the sub-millimeter droplet evaporationcharacteristics of the corrosive dinitrogen tetroxide（NTO, one prevailing hypergolic oxidizer） athigh ambient pressure up to 4.5 MPa. An in-house corrosion-resistant droplet generator is usedto generate isolated flying droplets of sub-millimeter size, which are then exposed in a gas environ-ment with temperatures between 1 010 K and 1 210 K and pressures in the range between 2.0 MPaand 4.5 MPa, provided by an optical rapid compression machine. Parallelly, a theoretical modelconsidering both the droplet ambient convection and the NTO dissociation is developed. Resultsindicate that firstly, the present theoretical model that considers the transient droplet-ambient con-vection as well as the temperature and pressure dependent rate of dissociation shows good agree-ment with the experimentally observed droplet lifetime. In addition, the flying droplets velocityregress gradually due to momentum exchange with the ambient, which is more prominent at higherpressure. The evaporation caused droplet size reduction is consistent with the classical D2-law pre-diction, in the present temperature and pressure range. Finally, higher temperature and pressureaccelerate the evaporation and an empirical correlation for the temperature and pressure dependentevaporation rate constant is proposed, which shows good agreement with experiment and simula-tion results.

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Pilot-Scale Photoreforming of Hydrolyzed Polylactic Acid Waste to High-Value Chemicals and H2 via Atomic Ru Integration

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Advanced Energy Materials 2025年第0期

作者： Liu, Feng Zhang, Chunyang Lu, Kejian Yan, Xueli Wang, Yi Jing, Dengwei Guo, Liejin Liu, Maochang International Research Center for Renewable Energy & State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an710049 China Suzhou Academy of Xi'an Jiaotong University Jiangsu Suzhou215123 China

Photoreforming of polylactic acid (PLA) waste into valuable chemicals offers a promising approach for environmental protection and waste valorization, yet faces challenges of low yields and harsh conditions. Herein, a Cd0.5Zn0.5S nanotwin catalyst decorated with Ru single atoms and clusters is reported, enabling selective photoreforming of PLA into pyruvic acid (PA) and H2. It is demonstrated that Ru single atoms favor PA formation via hydroxyl dissociation, while the further incorporation of Ru clusters serve as active sites for H2 production. This synergistic effect significantly enhances photocatalytic performance, achieving 96.8% PA selectivity and efficient H2 production with a record-breaking apparent quantum efficiency of 83.7% at 400 nm. This approach is scalable for outdoor processes, utilizing direct 1 m2 sunlight irradiation to deliver ≈1191 mL h−1 of H2 and 47.27 mmol h−1 of PA from PLA waste, paving a viable pathway for large-scale simultaneous production of high-value chemicals and H2. © 2025 Wiley-VCH GmbH.

关键词： Photolysis

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Numerical Study of Multi-Factor Coupling Effects on Energy Conversion Performance of Nanofluidic Reverse Electrodialysis

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Frontiers in Heat and Mass Transfer 2025年第2期23卷 507-528页

作者： Hao Li Cunlu Zhao Jinhui Zhou Jun Zhang Hui Wang Yanmei Jiao Yugang Zhao School of Physical and Mathematical Sciences Nanjing Tech UniversityNanjing211816China MOE Key Laboratory of Thermo-Fluid Science and Engineering Xi’an Jiaotong UniversityXi’an710049China Key Laboratory of Unsteady Aerodynamics and Flow Control Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing210016China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering School of Energy and Power EngineeringUniversity of Shanghai for Science and TechnologyShanghai200093China Key Laboratory of Icing and Anti/De-icing China Aerodynamics Research and Development CenterMianyang621000China

Based on the rapid advancements in nanomaterials and nanotechnology,the Nanofluidic Reverse Electrodialysis(NRED)has attracted significant attention as an innovative and promising energy conversion strategy for extracting sustainable and clean energy fromthe salinity gradient ***,the scarcity of research investigating the intricate multi-factor coupling effects on the energy conversion performance,especially the trade-offs between ion selectivity and mass transfer in nanochannels,of NRED poses a great challenge to achieving breakthroughs in energy conversion *** numerical study innovatively investigates the multi-factor coupling effect of three critical operational factors,including the nanochannel configuration,the temperature field,and the concentration difference,on the energy conversion processes of *** this work,a dimensionless amplitude parameter s is introduced to emulate the randomly varied wall configuration of nanochannels that inherently occur in practical applications,thereby enhancing the realism and applicability of our *** results reveal that the application of a temperature gradient,which is oriented in opposition to the concentration gradient,enhances the ion transportation and selectivity simultaneously,leading to an enhancement in both output power and energy conversion ***,the increased fluctuation of the nanochannel wall from s=0 to s=0.08 improves ion selectivity yet raises ion transport resistance,resulting in an enhancement in output power and energy conversion efficiency but a slight reduction in ***,with increasing the concentration ratio cH/cL from 10 to 1000,either within a fixed temperature field or at a constant dimensionless amplitude,the maximumpower consistently attains its optimal value at a concentration ratio of 100 but the cation transfer number experiences amonotonic decrease across this entire range of concentration ***,uponmodifying the ope

关键词： Salinity gradient energy nanofluidic reverse electrodialysis energy conversion nanochannel configuration multi-factor coupling effect

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Chromium Promoted the Efficient and Stable Catalytic Degradation of Propane Over Pt/Hzsm-5 Catalyst: Optimization and Reaction Mechanism

SSRN

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SSRN 2025年

作者： Jian, Yanfei Xu, He Wang, Yao Wang, Jingjing Xia, Lianghui Liu, Yujie Yu, Yanke He, Chi State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Shaanxi Xi'An710049 China National Engineering Laboratory for VOCs Pollution Control Material and Technology University of Chinese Academy of Sciences Beijing101408 China Yunnan University China

Light alkanes are a class of ubiquitous volatile organic compounds (VOCs), which bring great environmental hazards and health risks. However, low-temperature degradation of light alkanes is still a great challenge. Herein, a series of Pt/HZSM-5 catalysts without/with additives of Cr were fabricated. Catalytic performance of the catalyst for C3H8 low temperature combustion was investigated. It was found that Cr element had a significant effect on the activity of Pt/HZSM-5. Pt/Cr1/HZSM-5 performed the best activity for C3H8, excellent high temperature stability and water resistance. Characterization results of catalysts indicated that the introduction of Cr element could fix Pt site to promote the dispersion of Pt on the support. Moreover, the interaction between Cr and Pt produced more active Pt species, surface active lattice oxygen and acidic sites, which could promote the activation of C-H bonds in C3H8. Theoretical calculations showed that the interface between Pt and Cr had stronger adsorption for O2 and C3H8, which could accelerate propane oxidation. In this study, the effect of transition metal elements on the promotion of noble metal catalysts in the low-temperature degradation of light alkanes was discussed in depth, and it provided a reference for the design of efficient noble metal molecular sieve catalysts. © 2025, The Authors. All rights reserved.

关键词： Molecular sieves

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Enhancing thin film boiling heat transfer through electric field and surface Macro-Structure Synergy: Insights from bubble dynamics modulation

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International Journal of Heat and Mass Transfer 2025年 249卷

作者： He, Changqiu Tian, Jiameng Chen, Yiqi Zhu, Yuchen Liu, Xin Wang, Hai Wang, Zhentao Cai, Benan Wang, Changqing Wang, Junfeng Zhou, Zhifu Chen, Bin School of Energy and Power Engineering Jiangsu University Zhenjiang212013 China School of Energy and Power Engineering Chongqing University Chongqing 400044 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Laboratory of Thermo-fluid Science and Nuclear Engineering School of Energy and Power Engineering Northeast Electric Power University Jilin 132012 China National Key Laboratory of Marine Engine Science and Technology Shanghai 201108 China

Improving boiling heat transfer in thin liquid films by employing external electrical fields and macro-structured surfaces presents promising for tackling the growing difficulties related to high-heat-flux thermal management in electronic devices. In this study, six distinct macro-structured surfaces are designed and fabricated to gain insight into how liquid film thickness, structural parameters, and applied voltage affect the efficiency of boiling heat transfer with ethanol as the coolant. High-speed imaging and precise heat transfer measurements are employed to characterize the boiling performance, providing insights into the underlying fundamentals driving the observed enhancements. Results reveal that applying a 4-kV voltage increases departure frequency of bubble by 86 % and a 28 % reduction in diameter, causing a 20 % improvement in critical heat flux (CHF). CHF is positively correlated with liquid film thickness and pin height, but negatively with pin spacing, achieving a 139 % increase under optimal conditions. Liquid film thickness was found to have the most significant impact on CHF, followed by pin spacing and applied voltage. By simplifying the void fraction equation, a new CHF correlation is proposed that introduces a dimensionless characteristic length, representing the relative effects between bubble size and film thickness, while accounting for the synergy between the electric field and surface macro-structure. © 2025 Elsevier Ltd

关键词： Electric heating

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Large eddy simulation on the wake characteristics of linearly stratified flow past a sphere

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Scientific Reports 2025年第1期15卷 1-13页

作者： Xia, Tianci Wei, Na Shi, Liuliu School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai 200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai 200093 China Key Laboratory of Power Machinery and Engineering of Ministry of Education Shanghai Jiao Tong University Shanghai 200240 China

In this study, Large Eddy Simulation (LES) has been employed to examine the influence of the Froude number (Fr) on the linearly stratified wake and internal waves behind a sphere at a subcritical Reynolds number of Re = 3700. Six distinct sets of models with varying Fr (Fr = 0.05, 0.25, 0.5, 1, 2, ∞) have been chosen to establish density linear stratification through the use of a User Defined Function (UDF). The analysis focuses on the impact of stratification on wake characteristics, velocity distribution, and the structure of internal waves within stratified flow. It is evident that density stratification plays a pivotal role in shaping wake structure. Notably, in stratified flows, wakes exhibit unique characteristics including the generation of internal waves, suppression of vertical velocity, and the emergence of oscillating wake patterns. The study reveals that a decrease in the Froude number leads to heightened vertical suppression of the wake and increased anisotropy of the velocity distribution. Furthermore, as the Froude number ascends from 0.05 to 2, the wake undergoes a transition from quasi-two-dimensional vortex shedding to three-dimensional turbulence. © The Author(s) 2025.

关键词： Froude number Internal wave Linearly stratified flow Wake

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