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Effect of torrefaction on the high temperature steam gasification of cellulose based upon the Gibbs free energy minimization

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Energy Procedia 2017年 142卷 603-608页

作者： Y.W. Huang M.Q. Chen J.J. Song Institute of Thermal Engineering School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing China Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale Beijing China Guohua Electric Power Branch China Shenhua Energy Company Limited Beijing 100025 China

The steam gasification can convert biomass into syngas, which can be conveniently used as fuels or chemical raw materials. Cellulose, as an important component of biomass, has a significant effect on the gasification behavior. Steam gasification behaviors of raw and torrefied cellulose at high temperature were investigated using a non-stoichiometric equilibrium model. The effect of torrefaction severity on the high temperature steam gasification of cellulose was evaluated. With increasing of steam/cellulose molar ratio, the molar numbers of hydrogen and carbon dioxide increased, whereas the molar number of carbon monoxide decreased. Less than 1.0 molar ratio of steam/cellulose was recommended for raw and torrefied celluloses. The methane steam reaction for severely torrefied cellulose at low steam/cellulose molar ratio was found. The molar number of the hydrogen increased from 1.992 to 2.016 mol with the increasing of torrefaction temperature from 250 to 300 °C. The influence of steam content on the water-gas reaction was more obvious than that of reaction temperature. This study will promote the development of steam gasification of biomass for the purpose of high efficiency utilization.

关键词： Cellulose Steam gasification Torrefaction Thermodynamic equilibrium model High temperature

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The effects of Na+ and Cl-ions on the oil-water interface: a molecular dynamics study

The effects of Na+ and Cl-ions on the oil-water interface: a...

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2016年大连国际微纳流体和微流控芯片大会(2016 International Conference of Microfluidics, Nanofluidics and Lab-On-A-Chip

作者： Boyao Wen Chengzhen Sun Bofeng Bai State Key Laboratory of Multiphase Flow in Power Engineering Xi''an Jiaotong UniversityXi ''an Shaanxi 710049 China

Ions at the oil-water interface is a ubiquitous phenomenon which plays a important role in many industrial processes, such as extraction separation, nanoparticle assembly, enhanced oil recovery, *** the petroleum industry, due to the long-term interaction with solids and crude oil, the water including formation water, injection water and aqueous solution dissolves lots of ions, such as Na+, K+, Ca2+, Mg2+, Cl-, SO42-, *** migration of charged ions in the bulk phase or interface between oil and water has a significant influence on the molecudar packing of active species at the interface, zeta potential of oil droplets and microstructure and strength of interfacial film by changing the interfacial tension, interface viscosity and electrical repulsion of charged ganglia, thus affecting the stability of crude oil emulsions and the oil displacement in porous ***, more detailed knowledge of how ions affect the properties of oil-water interface is required.

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Towards efficient solar-to-hydrogen conversion: Fundamentals and recent progress in copper-based chalcogenide photocathodes

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Nanophotonics 2016年第4期5卷 468-491页

作者： Chen, Yubin Feng, Xiaoyang Liu, Maochang Su, Jinzhan Shen, Shaohua International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'An Jiaotong University Shaanxi710049 China

Photoelectrochemical (PEC) water splitting for hydrogen generation has been considered as a promising route to convert and store solar energy into chemical fuels. In terms of its large-scale application, seeking semiconductor photoelectrodes with high efficiency and good stability should be essential. Although an enormous number of materials have been explored for solar water splitting in the last several decades, challenges still remain for the practical application. P-type copper-based chalcogenides, such as Cu(In, Ga)Se2 and Cu2ZnSnS4, have shown impressive performance in photovoltaics due to narrow bandgaps, high absorption coefficients, and good carrier transport properties. The obtained high efficiencies in photovoltaics have promoted the utilization of these materials into the field of PEC water splitting. A comprehensive review on copper-based chalcogenides for solar-to-hydrogen conversion would help advance the research in this expanding area. This review will cover the physicochemical properties of copper-based chalco-genides, developments of various photocathodes, strategies to enhance the PEC activity and stability, introductions of tandem PEC cells, and finally, prospects on their potential for the practical solar-to-hydrogen conversion. We believe this review article can provide some insights of fundamentals and applications of copper-based chalco-genide thin films for PEC water splitting. © 2016 Y. Chen et al.

关键词： Photocathodes

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Research on droplets growth of Marangoni condensation during the time-series process

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Journal of Physics: Conference Series 2017年第1期925卷

作者： Y Li J Wang K Xia N Chen J Yan State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'lan 710049 P.R. China

In this paper, the condensate droplets growth of Marangoni condensation during the time-series process was experimentally studied. The photographs taken in the experiments were handled by image processing method. The droplets coverage ratio was introduced to analyse the growth process. As the time-series process went on, the condensate droplets coverage ratio increased fast at first, and then increased slowly until reaching a stable state. The droplets coverage ratio increased with the increase in the vapor-to-surface temperature difference and decreased with the increase in the ethanol vapor concentration.

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Simulation and experimental study of phase isolation induced by a static cyclone device in a vertical upward pipe

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International Journal of Energy for a Clean Environment 2015年第1-4期16卷 139-156页

作者： Wang, Shuai Wang, Dong Niu, Pengman Zhang, Xingkai State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

The study puts forward a forced way to realize phase isolation by using a static cyclone device and provides a basis for a systematic study of the phase-isolation phenomenon for an oil-water two-phase flow in a vertical upward pipe. An optimized style of the static cyclone device was chosen to simulate the phase-isolation characteristics that are influenced by various flow parameters (density, viscosity, velocity, oil diameter, etc.). It is observed that the phase-isolation characteristics are well approaching the ideal condition with the oil superficial velocity below 0.20 m/s and water superficial velocity between 0.25 and 0.8 m/s. The experimental results, which agree well with the simulation, also show that the static cyclone device can successfully be used to realize phase isolation. The phase-isolation method may provide an innovative approach to the measurement of phase holdup, the process of water reinjection, and the heat and mass transfer rates of a multiphase flow. © 2015 by Begell House, Inc.

关键词： Two phase flow

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Experimental Research on Macroscopic and Microscopic Characteristics of Ethanol-Fatty Acid Methyl Ester Blends Sprays 1

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2016中国汽车工程学会年会暨展览会

作者： Li Junge Yu Xiaocao Liu Bin Hu Tiegang Wang Xibin Powertrain Engineering R&D Center Changan automobile Co.Ltd State Key Laboratory of Multiphase Flows in Power Engineering Xi'an Jiaotong University

ISBN: (数字)9789811035272

ISBN: (纸本)9789811035265;9789811098963

Spray characteristics of Ethanol- Fatty Acid Methyl Ester Blends under common- rail injection condition were experimental investigated,by the high speed photography and particle/droplet image analyses(PDIA).The results show that spray cone angle and project area is increased with the increase of ethanol percentage and ambient *** mean diameter(SMD) increases with the increased axial distance at the same radial *** sharply decreases with the increased injection pressure,the average amplitude is 2μ*** of FAME decreases about 3μm after mixing *** characteristics of Ethanol-Fatty Acid Methyl Ester Blends and diesel are similar,thus the engine is rarely modified while fueled with FAME/Ethanol blends.

关键词： fatty acid methyl ester ethanol particle/droplet image analyses spray characteristics

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First principles investigation of quantum emission from hBN defects

arXiv

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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

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A measuring method for 3-D movement of particles using single-lens dual-camera system

A measuring method for 3-D movement of particles using singl...

引用

IEEE International Workshop on Imaging Systems and Techniques (IST)

作者： Minhua Jia Wu Zhou Na Jin Xiaoshu Cai Institute of Particle and Two-phase Flow Measurement / Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology Shanghai China

ISBN: (纸本)9781509018185

A 3-D measuring method for particle movement was established by using a single-lens dual-camera system. The light through an object-space telecentric lens was split half-and-half by a beam splitter and then are received by two CCD industrial cameras, respectively. These two image sensors have different distances from the telecentric lens. As for the same imaging particle, two images with different degrees of defocus will be captured. These two images were used to solve the ambiguous problem of 3-D particle positions. Combining with the PTV technology and the single-frame and multiple-exposure imaging method, the system can determine the magnitude and direction of 3-D velocity. The feasibility was then proved by experiments.

关键词： Atmospheric measurements Particle measurements Lenses Cameras Measurement by laser beam Velocity measurement

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Molecular dynamics simulation of the adsorption of sodium dodecyl benzene sulfonate at the decane-water interface

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Kung Cheng Je Wu Li Hsueh Pao/Journal of engineering Thermophysics 2016年第5期37卷 1011-1015页

作者： Wen, Bo-Yao Sun, Cheng-Zhen Che, Yu-Quan Bai, Bo-Feng State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Frist Gas Production Factory PetroChina Xinjiang Oilfield Branch Company Karamay834000 China

Molecular dynamics method was employed to explore the micro-characteristic of decane-water interface with the adsorption of sodium dodecyl benzene sulfonate (SDBS). We analyzed the effect of interfacial molecular arrangement on the micro-structure and properties of oil-water interface from concentration distribution and molecular conformation insights. The results show that the thickness of decane-water interface is 0.378 nm. Both decane molecules and the dipole moment of water molecules tend to be parallel to the interface. The aggregation of surfactants at the interface increases the thickness of oil-water interface, therefore weakening the oil-water interaction and disrupting the directional alignment of water and decane molecules. Meanwhile, we found that there are some cavities at the decane-water interface, combining with the strong electrostatic interaction between hydrophilic groups and water molecules, can aggravate the diffusion of water molecules at the interface, thus enhancing the deformation ability of the interface. © 2016, Science Press. All right reserved.

关键词： Molecular dynamics

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The Development of Candling Module Code in Module In-vessel Degraded Analysis Code MIDAC and the Relevant Calculation for CPR1000 During Large-Break LOCA

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Journal of Nuclear engineering and Radiation Science 2016年第2期2卷 021002页

作者： Wang, Jun Fan, Yuqiao Zhang, Yapei Ni, Xinghe Tian, Wenxi Corradini, Michael L. Su, Guanghui Qiu, Suizheng State Key Laboratory of Multiphase Flow in Power Engineering Department of Nuclear Science and Technology Xi’an Jiaotong University Xi’an 710049 China College of Engineering University of Wisconsin-Madison Madison WI 53706

The occurrence of Fukushima has increased the focus on the development of severe accident codes and their applications. As a part of Chinese “National Major Projects,” a module in-vessel degraded analysis code (MIDAC) is currently being developed at Xi’an Jiaotong University. The developing situation of a candling module and relevant calculation for CPR1000 for large break loss of coolant analysis (LOCA) are presented in this paper. The candling module focuses on the melting, moving, and relocation of the melting core materials and necessary thermal hydraulic information. MIDAC’s LOCA accident calculation results of Chinese pressure reactor 1000 (CPR1000) cover the melting mass distribution, peak temperature, and hydrogen generation. The results have been compared with MAAP. Through comparison, the candling module of MIDAC proved to be able to predict the moving trend of the molten material mass relocation in the reactor pressure vessel.

关键词： Melting MIDAC CPR1000 Vessels MAAP severe accident flow (Dynamics) Accidents LOCA Temperature Hydrogen

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