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Research on the two-phase flow and separation mechanism in the oil-gas cyclone separator

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IOP Conference Series: Materials Science and engineering 2015年第1期90卷

作者： L Z Wang X Gao J M Feng X Y Peng School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049China

The cyclone separator has attracted increasing attention due to its small size, rapid construction and high separation efficiency. This study investigated its gas-liquid two-phase flow and separation characteristics experimentally and numerically. A numerical model of two- phase flow in the cyclone separator was proposed using the Euler-Lagrange method. The distribution of pressure, tangential and axial velocity in the gas-phase flow field was obtained, and the oil droplet movement was traced. Separation efficiency was also studied experimentally, and the diameter distributions of oil droplets at the inlet and the outlet of the separator were measured by a Malvern laser particle size analyser to verify the simulation model. Based on high-speed photography technology, the oil film distribution and flow pattern on the wall of the cyclone separator were visualised. The variation of oil-gas two-phase flow in the cyclone separator was compared under various inlet flow rates. Based on the results, an improved structure was proposed, and the performance of the improved separator was investigated experimentally.

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Comparison of Chemical Composition and Acidity of Size-Resolved Inorganic Aerosols at the Top and Foot of Mt. Hua, Northwest China: The Role of the Gas-Particle Distribution of Ammonia

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SSRN 2023年

作者： Li, Jianjun Feng, Qiao Liu, Haijiao Dai, Wenting Cao, Yue Shen, Minxia Liu, Yali Qi, Weining Chen, Yukun Guo, Xiao Zhang, Yifan Li, Lu Zhou, Bianhong State Key Laboratory of Loess and Quaternary Geology Key Lab of Aerosol Chemistry and Physics Institute of Earth Environment Chinese Academy of Sciences Xi’an710061 China College of Geography and Environment Baoji University of Arts and Sciences Shaanxi Key Laboratory of Disaster Monitoring and Mechanism Simulation Baoji721013 China Xi’an Institute for Innovative Earth Environment Research Xi’an710061 China National Observation and Research Station of Regional Ecological Environment Change and Comprehensive Management in the Guanzhong Plain Shaanxi China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

Aerosol pH is not only a diagnostic indicator of secondary aerosol formation, but also a key factor in the specific chemical reaction routes that produce sulfates and nitrates. To understand the characteristics of aerosol acidity in the Mt. Hua, the chemical fractions of water-soluble inorganic ions in the atmospheric PM2.5 and size-resolved particle at the top and foot of Mt. Hua in summer 2020 were studied. The results showed the mass concentrations of PM2.5 and water-soluble ions at the foot were 2.0-2.6 times higher than those at the top. The secondary inorganic ions, i.e. SO42-, NO3-, and NH4+ (SNA) were 56%-61% higher by day than by night. SO42- was mainly distributed in the fine particles (Dp 2.1 µm) was mainly attributed to the gaseous HNO3 volatilized from fine particles reacting with cations in coarse particles to form non-volatile salts (such as Ca(NO3)2). The pH values of PM2.5 were 2.7 ± 1.3 and 3.3 ± 0.42 at the top and foot, respectively. NH4+/NH3(g) plays a decisive role in stabilising aerosol acidity. In addition, the increase of the liquid water content (LWC) at the foot facilitates the gas-particle conversion of NH3, while the H+ concentration was diluted, resulting in a decrease in acidity at the foot. NH4+/NH3 had good linear correlations with SO42−, NO3－, and LWC during the daytime at both sites, indicating that SO42−, NO3－, and LWC together affect the gas-particle distribution of ammonia by day: however, the effect of LWC at night was not evident. © 2023, The Authors. All rights reserved.

关键词： Ammonia

On-Line Measurement of Ultralow Mass Concentration Particulate Based on Light Scattering Coupled with Beta Ray Attenuation Method

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SSRN 2022年

作者： Liu, Xiaowei Huang, Yubo Wang, Zhaofeng Jiang, Meng Zhou, Zijian Xu, Minghou Han, Jinke Yang, Bin Fan, Xinfeng State Key Laboratory of Coal Combustion School of Energy and Power Engineering Huazhong University of Science and Technology 1037 Luoyu Road Wuhan430074 China JXIC Energy Technology Research Institure Nanchang330000 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Wuhan Tianhong Environmental Protection Industry Co. Ltd Yuhong Environmental Protection Science and Technology Industrial Park No.11 Huashiyuan North Road Miaoshan District Donghu high tech Development Zone Wuhan430074 China

Light scattering method is the most commonly used method for on-line measurement of ultralow particulate matter mass concentration. However, when the particle characteristics change, the effectiveness of the empirical relationship decreases, which would lead to a sizeable deviation. To accurately measure the mass concentration of particulate matter in real-time, a coupling measurement idea of light scattering and beta-ray attenuation is proposed. The beta-ray attenuation is little affected by particle properties and accurately reflects the average PM mass concentration in the measured period. The single calibration method (M1), periodic calibration method (M2), average calibration method (M3), and asymmetric factor calibration method (M4) are formed based on the coupling idea. The results of all methods are perfect when the particle size is unchanged. However, when the particle sizes fluctuate frequently, the results of M1, M2, and M3 deviate seriously from the actual value, and the applicable working conditions have limitations. The results of M4 are in good agreement with the actual value, and the effectiveness is not limited by the particle size. Finally, the prototype based on experimental exploration was developed and had been continuously operated for more than 528 hours at a 1000 MW unit of a coal-fired power plant. © 2022, The Authors. All rights reserved.

关键词： Particle size

Particle-Scale Modelling of Injected Hydrogen and Coke Co-Combustion in the Raceway of an Ironmaking Blast Furnace

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SSRN 2022年

作者： Dianyu, E. Zhou, Peng Ji, Langyong Cui, Jiaxin Xu, Qiang Guo, Liejin Yu, Aibing International Institute for Innovation Jiangxi University of Science and Technology Ganzhou341000 China Jiangxi Provincial Key Laboratory for Simulation and Modelling of Particulate Systems Jiangxi University of Science and Technology Ganzhou341000 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China ARC Research Hub for Computational Particle Technology Department of Chemical Engineering Monash University VIC3800 Australia Centre for Simulation and Modelling of Particulate Systems Southeast University Monash University Joint Research Institute Suzhou215123 China

Hydrogen is an environmentally friendly fuel that does not produce greenhouse gas (GHG) emissions. Its applications have attracted significant attention from many industries, especially the ironmaking industry, which consumes massive amounts of fossil energy. The injection of hydrogen into a blast furnace (BF) is one of the most promising low-carbon ironmaking routines. In this study, an experimentally validated CFD-DEM model is adopted to investigate the dynamics, microstructure and thermochemical behaviours in the raceway of a BF with hydrogen injection operations (HIOs), which include raceway evolution, force distribution and the co-combustion characteristics of hydrogen and coke. Some significant features are obtained through comparison analyses between HIOs and air injection operations (AIOs). In particular, the effects of the hydrogen injection concentration on the raceway size, gas temperature and components are studied. The simulation results show that a smaller raceway is formed under HIOs in comparison with that of AIOs. In addition, the gas temperature is higher near the tuyere but lower along the tuyere axis, and the oxygen consumption is larger and produces more CO. As the hydrogen injection concentration increases: (i) the raceway size and gas temperature decrease;(ii) the CO is generated at the early stage and the maximum CO2 concentration moves to inlet direction along the tuyere axis. The results provide insights on the fundamental understanding of low-carbon ironmaking BF technology. © 2022, The Authors. All rights reserved.

关键词： Blast furnaces

First principles investigation of quantum emission from hBN defects

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arXiv

arXiv 2017年

作者： Tawfik, Sherif Abdulkader Ali, Sajid Fronzi, Marco Kianinia, Mehran Tran, Toan Trong Stampfl, Catherine Aharonovich, Igor Toth, Milos Ford, Michael J. School of Mathematical and Physical Sciences University of Technology Sydney UltimoNSW2007 Australia Department of Physics GC University Faisalabad Allama Iqbal Road Faisalabad38000 Pakistan International Research Centre for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi710049 China School of Physics University of Sydney NSW2006 Australia

Hexagonal boron nitride (hBN) has recently emerged as a fascinating platform for room-temperature quantum photonics due to the discovery of robust visible light single-photon emitters. In order to utilize these emitters, it is necessary to have a clear understanding of their atomic structure and the associated excitation processes that give rise to this single photon emission. Here we perform density-functional theory (DFT) and constrained DFT calculations for a range of hBN point defects in order to identify potential emission candidates. By applying a number of criteria on the electronic structure of the ground state and the atomic structure of the excited states of the considered defects, and then calculating the Huang-Rhys (HR) factor, we find that the CBVN defect, in which a carbon atom substitutes a boron atom and the opposite nitrogen atom is removed, is a potential emission source with a HR factor of 1.66, in good agreement with the experimental HR factor. We calculate the photoluminescence (PL) line shape for this defect and find that it reproduces a number of key features in the the experimental PL lineshape. Copyright © 2017, The Authors. All rights reserved.

关键词： III-V semiconductors

Compositional Variations in Highly Active Ptsn/Al2o3 Catalysts Derived from Molecular Complexes

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SSRN 2023年

作者： He, Qian Xu, Chaokai Tan, Shengdong Tang, Yaxin Xi, Shibo Yao, Bingqing Wade, Austin Zhao, Binbin Lu, Shangchen Tian, Mingjiao He, Chi Ma, Lu Fu, Xingjie Shi, Jiwei Lu, Jiong Howe, Alexander G.R. Dai, Sheng Luo, Guangfu Du, Yankun Department of Material Science and Engineering College of Design and Engineering National University of Singapore 9 Engineering Drive 1 EA #03-09 Singapore117575 Singapore Department of Materials Science and Engineering Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology Guangdong Shenzhen518055 China 1 Pesek Road Jurong Island 627833 Singapore Thermo Fisher Scientific 5350 NW Dawson Creek Drive HillsboroOR United States State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China Brookhaven National Laboratory UptonNY11973 United States Department of Chemistry National University of Singapore 12 Science Drive 2 117549 Singapore Key Laboratory for Advanced Materials Joint International Research Laboratory of Precision Chemistry and Molecular Engineering School of Chemistry and Molecular Engineering East China University of Science & Technology Shanghai200237 China

We investigated the industrially important PtSn/Al2O3 catalysts prepared with uniform particle sizes (~ 1 nm) and varied compositions using molecular complexes of Pt(II) and Sn(II). Our best catalyst, with a Sn:Pt ratio of around 2, exhibited a high initial propylene productivity of about 1.1 mol C3H6 (g catalyst)-1 h-1. Elaborate electron microscopy studies revealed significant compositional variations in the catalyst, highlighting the practical challenges in achieving or confirming the theoretically predicted optimum Sn:Pt ratio. It is also found that the catalytic activities correlate well with the Pt dispersion, suggesting the structure-insensitive nature of the dehydrogenation reaction applies in these ultrasmall Pt-Sn nanoparticles. The presence of Pt-rich particles in the catalysts did not produce noticeable degradations in the reaction selectivity, indicating a wide composition range for Pt-Sn nanoparticles to be effective at the 1 nm size range. These findings emphasize the importance of detailed analysis of compositional distributions for understanding nanoalloys. © 2023, The Authors. All rights reserved.

关键词： Electron microscopy

Two-phase distributor in plate fin heat exchanger

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Huagong Xuebao/CIESC Journal 2011年第SUPPL. 1期62卷 31-36页

作者： Yuan, Pei Jiang, Guobao Zhang, Feini He, Yaling Tan, Minbang Tao, Wenquan School of Energy and Power Engineering State Key Laboratory of Multi-phase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi China Company Jianyang 641400 Sichuan China

The maldistribution of two-phase flow is one of the major factors that deteriorate the heat transfer performance of plate-fin heat exchanger. The set-up of flow distributor at the heat exchanger inlet is one widely adopted engineering method to improve the flow distribution. In this paper the flow distribution performance of one type of distributor is experimentally tested by using air-water mixture. The test results show that the flow distributor studied can improve the two-phase flow distribution uniformity in plate-fin heat exchanger. © All Rights Reserved.

关键词： Two phase flow

Facile Synthesis of Bulk Au-Co-Coox-Ceox@Iron Ball and its Photocatalytic Application in 4-Nitrophenol Degradation

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SSRN 2023年

作者： Sun, Li Qiao, Zhili Zhi, Yuan Zhang, Hua Dou, Binlin Shan, Yuejin Huang, Weijia School of Energy and Power Engineering University of Shanghai for Science and Technology Jun Gong Road 516 Shanghai200093 China R&D Department Shanghai Minrula Biotechnology Co.Ltd Building 15 Haji Sixth Road 218 Shanghai201306 China Department of Material and Environmental Chemistry Research Division of Functional Materials Design Utsunomiya University Yoto 7-1-2 Utsunomiya321-8585 Japan Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering China

Bulk noble metal-semiconductor composites can be chosen as photocatalysts to carry out the continuous-flow (C-F) degradation of 4-nitrophenol (4-NP) whereas their preparation is complex and uncontrollable. Here, bulk Au/Co-CC@iron ball is designed and prepared by a facile and controllable route without any toxic chemical. The bulk Au/Co-CC@iron ball shows excellent photocatalytic activity and reusability for the 4-NP degradation, which can be ascribed to the synergistic action of active components and foliated iron ball surface. Furthermore, the highly active Au/Co-CC@iron ball is used as packing material to construct a new-type of packed reactor, by which the C-F degradation of 4-NP is successfully achieved. As-fabricated packed reactor and its tandem module exhibit superior photocatalytic performance for the C-F degradation of 4-NP. Noteworthy, based on the tandem module with six reactors, the removal rate of 4-NP can reach up to 2750 µmol/h. Meanwhile, the reactor and its module display satisfactory operational stability and reusability in the C-F degradation of 4-NP. Clearly, the provided route is effective for the preparation of bulk noble metal-semiconductor composites with exceptional performance, which can also be a prospective strategy to obtain bulk packing materials to serve for the C-F degradation. © 2023, The Authors. All rights reserved.

关键词： Precious metals

Pore-scale modelling on hydrogen transport in porous media: Implications for hydrogen storage in saline aquifers

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International Journal of Hydrogen Energy 2023年第37期48卷 13922-13933页

作者： Jinlei Wang Yongfei Yang Shaobin Cai Jun Yao Quan Xie Key Laboratory of Unconventional Oil & Gas Development (China University of Petroleum (East China)) Ministry of Education Qingdao 266580 PR China Research Center of Multiphase Flow in Porous Media School of Petroleum Engineering China University of Petroleum (East China) Qingdao 266580 PR China WA School of Mines: Minerals Energy and Chemical Engineering Curtin University 26 Dick Perry Avenue 6151 Kensington Western Australia Australia

Hydrogen energy has tremendous potential as a clean fuel in this energy transition. To build up the full-scale hydrogen energy supply chain, large-scale hydrogen storage is of vital importance. Underground hydrogen storage in saline aquifers has been perceived as an important means to achieve large-scale hydrogen storage. Therefore, we investigated hydrogen transport in pore network in a sandstone porous media at strongly water-wet and weakly water-wet (hydrogen-wet). We performed direct numerical simulation through volume of fluid method to investigate the transport of hydrogen at pore-scale under different wetting conditions with input hydrogen-rock physics data from literature. Our results showed that during primary drainage process (hydrogen injection for storage purpose), increasing hydrogen wetting decreased snap-off effect, enabling a greater pore space for hydrogen storage. During primary imbibition process (hydrogen extraction), increasing hydrogen wetting promoted the size and stability of hydrogen clusters, which is unfavorable to hydrogen extraction process. Given the significant high interfacial tension between brine and hydrogen and low viscous force of hydrogen, snap-off effect dominates the flow in both hydrogen injection and extraction process regardless of wetting conditions. This physical process causes the recovery factor even below 20%. We therefore suggest that storing hydrogen in depleted gas reservoirs under irreducible water saturation would have much less risks in hydrogen trapping during extraction process.

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