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

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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Prediction of acoustic agglomeration enhanced by solid seed particles using the DSMC method

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Advanced Powder Technology 2025年第6期36卷

作者： Su, Junxu Wu, Zhihao Fan, Fengxian Hu, Xiaohong Su, Mingxu School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology Shanghai200093 China

Acoustic agglomeration enhanced by large-sized solid seed particles is investigated using the direct simulation Monte Carlo (DSMC) method. The process of acoustic agglomeration is revealed in terms of temporal evolution of velocities, diameters, and number weights of simulated particles, as well as normalized concentration and average diameter of small particles. Furthermore, the enhancement of acoustic agglomeration by the solid seed particles is evaluated at varying parameters. The results show that the agglomeration performance is enhanced within a shorter residence time when the solid seed particles are present. Increasing acoustic intensity or solid seed particle concentration leads to more efficient acoustic agglomeration, while the acoustic frequency, particularly beyond 2 kHz, has little effect on agglomeration performance. Moreover, a noticeable increase in agglomeration efficiency is observed when the seed particle diameter increases from 20 to 40 µm. However, once it exceeds 40 µm, the increase in agglomeration efficiency diminishes. © 2025 The Society of Powder Technology Japan.

关键词： Agglomeration

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New coordinated control strategy of boiler-turbine with storage system based on the heat to power conversion characteristics for operational flexibility enhancement

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Journal of Energy Storage 2025年 123卷

作者： Wang, Zhu Yan, Hui Zhao, Yongliang Wang, Chaoyang Wang, Jinshi Liu, Ming State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an China Department of Electrical and Electronic Engineering University of Manchester ManchesterM13 9PL United Kingdom

High flexibility is essential for maintaining the safe and stable operation of power systems with a high-proportion of intermittent renewable energy generation. Integration of an energy storage system is an effective way to improve the flexibility of thermal power plants. In this manuscript, a new coordinated control strategy based on the load decomposition, considering the heat to power conversion characteristics of a boiler-turbine with an energy storage system, is proposed to improve the flexibility of the power plants. The core concept of the load decomposition is that the turbine load commands equals the sum of boiler and energy storage system load commands. The proposed new coordinated control strategy is examined by a case study of a boiler-turbine with energy storage system. The results show that the maximum load down and up rates are up to 7.0 % and 6.5 % Pe0 min−1, and the maximum reductions in standard coal consumption rates during load down and up are 1.4 and 1.8 g kWh−1, respectively. Additionally, the round-trip energy efficiency of the turbine-boiler-storage system during load down and up is improved by decreasing the extraction steam/water ratio or increasing the load cycling rate during load up. This study provides a comprehensive guide for enhancing the operational flexibility through the coordinated operation of the boiler, turbine, and energy storage systems. © 2025 Elsevier Ltd

关键词： Steam power plants

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Development of a two-phase flow solver with two-fluid model based on OpenFOAM: Validation against two-phase boiling flow

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Annals of Nuclear Energy 2025年 220卷

作者： Wu, Wenqiang Huang, Tao Du, Peng Feng, Zhenyu Zhang, Dalin Zhou, Lei Song, Gongle Deng, Jian Qiu, Zhifang Tian, Wenxi Qiu, Suizheng Su, Guanghui State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi'an Jiaotong University Shaanxi Xi'an710049 China Nuclear Power Institute of China 328 Changshun Avenue Chengdu610213 China

The continuous advancement in computer technology and mathematical-physical models has significantly propelled the development of numerical reactor technology. There is a growing focus on high-fidelity, multi-scale, and multi-physics coupling within a unified framework. OpenFOAM, based on the finite volume method, has emerged as a promising tool for addressing this challenge. This study explores its capabilities in system-level scales, successfully developing a two-fluid, six-equation solver. The realistic closure models cover flow and heat transfer scenarios within vertical channels under pre-CHF conditions. A virtual thermal structure accounts for conjugate heat transfer between the fluid and the solid. Furthermore, the solver adheres to the discretization and solution principles within the OpenFOAM framework. The developed solver has been extensively validated against experimental data for two-phase boiling flow, with results showing good agreement, thereby demonstrating the solver's success. This work builds upon previous efforts involving the drift-flux solver and indicates that OpenFOAM can effectively handle one-dimensional or system-level scale calculations. It provides robust support for future endeavors in multi-scale and multi-physics coupling technologies. © 2025 Elsevier Ltd

关键词： Finite volume method

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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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Efficient conversion of CO2 to CH4 through supercritical water gasification of plastic with calcium looping

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Renewable Energy 2025年 249卷

作者： Li, Xuantong Wu, Hongtu Wang, Weizuo Wang, Junying Wu, Chunfei Jin, Hui State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an710049 China School of Chemistry and Chemical Engineering Queen's University Belfast BelfastBT9 6FS United Kingdom

Calcium looping (CaL) is a promising technology with significant implications for carbon capture. However, the traditional CaL requires a high temperature of 950 °C for CaCO3 decomposition, posing challenges for further development due to stringent temperature conditions. This study leverages the advantages of a hydrogen-rich reaction environment in a supercritical water gasification (SCWG) system to develop a thermodynamic model of a solar-driven SCWG system incorporating CaL. This innovation reduces the high-temperature requirement of traditional CaL by 41 %, lowering it to 560 °C, and simultaneously alleviates the coupling difficulty of solar-driven systems. The system utilises waste carbide slag (CS) to convert waste plastics into combustible CH4 and other industrial products, achieving thermochemical elimination of CO2 into CH4. Results indicate that CH4 production in traditional gasification systems increases with temperature, whereas the inclusion of CaL shows a trend of initial increase followed by a decrease, peaking at 560 °C with a 19.12 % increase compared to systems without CaL. Both energy and exergy efficiencies decline with temperature, while the impact of pressure on gasification performance and system efficiency remains below 10 %. Increasing the plastic-to-water ratio enhances CH4 production and energy and exergy efficiencies but reduces the gas yield per unit of plastic. © 2025

关键词： Exergy

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Decoupling the heating and reduction processes in solar-driven two-step thermochemical cycle by coupling it with thermal power generation

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Energy 2025年 324卷

作者： Zhu, Liya Mao, Jinxin Du, Jinyang Han, Fengshuang Zhao, Kai Lu, Youjun School of Electrical Engineering Zhengzhou University Zhengzhou450001 China School of Energy and Power Engineering North China University of Water Resources and Electric Power Zhengzhou450001 China School of Mechanical and Power Engineering Zhengzhou University Zhengzhou450001 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Solar-driven H2O/CO2 splitting via two-step thermochemical cycle is a promising path for renewable fuel production. However, the energy losses caused by the high solar thermal temperature and the significant technical challenges in oxygen carrier heat recovery have long hindered its efficiency improvement. In this work, the two-step cycle was proposed to couple with a thermal power generation process to recover the process heat, and the electricity generated was proposed to be used in the reduction step, for which the solar heating and reduction processes can be decoupled. Thermodynamic evaluation shows that an efficiency advantage over the traditional cycling mode can be expected even when the solar thermal temperature is 50 K lower. It is 16.1 % at Tred = 1773 K and Tsolar = 1723 K, significantly higher than that of the traditional cycle working at Tred = 1773 K with 95 % gas heat and 40 % solid heat recovered (13.6 %). The novel cycling mode not only provides a practical heat recovery strategy, but also creates a completely new space for further lowering the solar thermal temperature and brings about obvious engineering advantages. It is supposed to be of important implications in promoting the practical application of the technology. © 2025

关键词： Solar heating

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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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Integrated Co2 Capture and Conversion by Three-Step Chemical Looping Dry Reforming of Methane

SSRN

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SSRN 2025年

作者： Liu, Yunlian Liu, Mingkai Shen, Yuanhui Li, Yang Gai, Zhongrui Zhang, Ruqi Pan, Ying Jin, Hongguang Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing100190 China University of Chinese Academy of Sciences Beijing100049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

The integrated CO2 capture and conversion (ICCC) has emerged as a promising and cost-effective pathway for achieving carbon neutrality. However, limited energy-efficient pathways and durable materials for ICCC systems remains challenging. This study proposes a novel approach that synergistically integrates CO2 capture and conversion through a unified chemical framework. The method employs Li-based sorbents for CO2 capture, coupled with CH4-driven sorbent regeneration that is seamlessly integrated with chemical looping dry reforming of methane (CLDRM), enabling in-situ CO2 conversion. By coupling sorbent regeneration with CLDRM, this system enhances decarbonation kinetics through Le Chatelier's principle via continuous CO2 conversion. One-step calcination synthesized Li-based sorbents particles exhibit stable CO2 capture capacity of 5.25 mmol·g-1 within 15 min per cycle, maintaining 7.5-15% operational efficiency over 40 cycles at 600 ℃. In CLDRM, hydrogen radicals from CH4 dissociation promote the conversion of CO2 to intermediates, lowering the apparent activation energy of sorbents regeneration by 29.2%. Through systematic optimization in a fixed-bed reactor, we achieved 90% CO2 uptake and 85% CH4 conversion, with syngas production rates reaching 13.71 mL·min-1·g-1. Notably, the H2/CO molar ratio in syngas stabilizes ~1.6, aligns with iron-based Fischer-Tropsch and methanol synthesis to produce valuable fuels. This integrated system maintains >80% syngas purity with © 2025, The Authors. All rights reserved.

关键词： Activation energy

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A study on free radical behaviors and reactions in supercritical water using quantum chemical simulation

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Journal of Molecular Liquids 2025年 419卷

作者： Ding, Weijing Takahashi, Osamu Wang, Junying Jin, Hui School of Transportation and Vehicle Engineering Shandong University of Technology Shandong Zi'bo255000 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an710049 China of Advanced Science and Engineering Hiroshima University Higashi-Hiroshima739-8526 Japan

Supercritical water (SCW) gasification is one of clean and efficient utilization way of biomass, other organic matters or coal for hydrogen production, in which radical reactions studies in SCW are limited but crucial. Density-functional tight-binding (DFTB) molecular simulation is one of efficient and convenient approaches to investigate these microscopic processes. Therefore, free radical reactions in severe SCW environment were investigated via DFTB calculations in this work. The results showed that the order of the free radicals containing bond cleavages reacted in SCW environment was ·OH, ·CH, ·CH2, ·HO2, ·CH3 and ·C6H5 under the same conditions. The reaction processes of different radicals in SCW were obtained. ·H was the most active free radical of reactions. This work is expected to understand the properties of free radicals in SCW better and explore intrinsic reaction mechanisms, which may provide a theoretical support for accomplishing efficient and low-carbon complete SCW gasification for hydrogen production. © 2024 Elsevier B.V.

关键词： Free radical Gasification Hydrogen production Reaction Supercritical Water (SCW)

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