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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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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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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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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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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 extraction of valuable metals from spent LiNi0.5Co0.2Mn0.3O2 cathode materials using sodium bisulfate: Parameter optimization and kinetic study

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Sustainable Materials and Technologies 2025年 44卷

作者： Zhang, Pengyang Rohani, Sohrab Teng, Liumei He, Minyu Jin, Xi Liu, Qingcai Ren, Shan Liu, Weizao College of Materials Science and Engineering Chongqing University Chongqing400044 China Department of Chemical and Biochemical Engineering Western University LondonON Canada School of Materials Science and Engineering Chongqing University of Arts and Sciences 402160 China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an710049 China

Spent lithium-ion batteries pose significant environmental hazards but also possess high recycling value. In this study, a process for the recovery of valuable metals from spent LiNi0.5Co0.2Mn0.3O2 cathode materials (NCM523) was proposed by using NaHSO4 as the sulfation agent. The thermal decomposition of NaHSO4 and its sulfation roasting process with spent NCM523 were investigated. The findings revealed that NaHSO4 started decomposing at approximately 200 °C, releasing Na2S2O7. And significant SO2 gas was emitted after 400 °C, efficiently reducing and sulfating the valuable metals in NCM523. The sulfation roasting parameters were optimized by examining the influences of roasting temperature and the mass ratio of NaHSO4 to waste cathode materials on the leaching efficiencies of valuable metals. Experimental results indicated that Li was present as Li2SO4 and NaLiSO4 forms after roasting, while other valuable metals existed in complex forms, mainly as bimetallic composite sulfates. The study found that under optimal conditions, with a NaHSO4 to waste cathode material mass ratio of 5:1, and roasting at 600 °C for 120 min resulted in the highest leaching efficiencies for valuable metals, with Li at 98.4 %, Co at 97.1 %, Ni at 96.1 %, and Mn at 96 %. Additionally, the non-isothermal kinetic of the roasting process was studied, determining the apparent activation energy of each stage and identifying the controlling steps through the Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), and Starink methods. The mechanisms were elucidated using the Satava-Sestak and Coats-Redfern equations, which identified the fourth stage as the controlling step with an average activation energy of 211.4 kJ/mol, indicating a three-dimensional diffusion model. The results highlighted that utilizing NaHSO4 roasting for recycling waste cathode materials led to high leaching efficiencies of Li, Co, Ni, and Mn metals at lower temperatures. This aligned well with the principles of efficient

关键词： Lithium-ion batteries

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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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Discrete element simulation of dry adhesive granular flow in a vertical pipe

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Powder Technology 2025年 460卷

作者： Gao, Xin Parteli, Eric J.R. Fan, Fengxian School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Faculty of Physics University of Duisburg-Essen Lotharstr. 1 DuisburgD 47057 Germany Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology Shanghai200093 China

The transportation and storage of granular materials with adhesive properties often involves particulate flow through narrow pipes, which is accompanied by still poorly understood dynamic behavior. Due to the difficulty in achieving a quantitative understanding of such flows based solely on experiments, here we perform particle-based numerical simulations of vertical pipe flows of adhesive granular materials using the discrete element method (DEM). Our simulations unveil different regimes of vertical pipe flow depending on the pipe-to-particle diameter ratio and the interparticle adhesive strength. Surprisingly, we find that the particle mass flow rate through the pipe increases substantially with this adhesive strength. This rather counterintuitive result is caused by an enhanced tendency of the particles to form stable agglomerates around the pipe symmetry axis, thus leading to reduced interaction of the particles with the frictional pipe walls. By contrast, incorporation of particle-wall adhesive interactions leads to exactly the opposite behavior, with such interactions dictating the granular dynamics in the pipe and leading to lower mass flow rate values compared to cohesionless flows. Furthermore, we show that the different flow regimes are associated with distinct spatiotemporal patterns of the granular solid fraction along the pipe axis (density waves). Therefore, our results provide theoretical references for future experimental research and application of adhesive granular flows through narrow pipes. © 2025 Elsevier B.V.

关键词： Channel flow

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Preparation, improvement, and application of metal–organic framework-based sensing materials for gas leakage and emission: A review

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Nano Materials Science 2025年

作者： Liu, Manyi Wang, Liang Ren, Shan Bai, Bofeng Chai, Shouning He, Chi Zheng, Chunli Yin, Xitao Li, Fengguang College of Materials Science and Engineering Chongqing University Chongqing400044 China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an710049 China School of Physics and Optoelectronic Engineering Ludong University Yantai264000 China School of Materials Science and Engineering Hubei University of Automotive Technology Shiyan442002 China

Industrial gas leaks and flue gas emissions pose significant threats to the safety of industrial operations and the atmospheric ecological environment. Traditional gas sensing materials often struggle to meet the challenges posed by complex industrial environments. Recently, metal-organic framework (MOF)-based gas sensing materials have garnered significant attention in industrial gas detection due to their high sensitivity, selectivity, and tunable properties. The exponential increase in related publications highlights the growing research interest in this field. This paper presents a comprehensive review of the advantages of various types of metal-organic frameworks and their derivatives for detecting industrial gas leaks and flue gas emissions, alongside an introduction of representative MOF synthesis methods. Furthermore, the primary sensing mechanisms of MOF-based gas sensing materials and strategies for enhancing the sensing performance are summarized. The current state of MOF-based gas sensing materials in industrial gas detection is also discussed. Finally, the potential limitations, existing challenges, and future directions of MOF-based industrial gas sensing materials are systematically analyzed, with suggestions for addressing these challenges to advance industrial gas detection technologies. © 2025 Chongqing University

关键词： Application Improvement Industrial gas detection MOF-Based sensing materials Preparation

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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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