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International Conference on Power engineering 2013, ICOPE 2013

作者： Han, Xiaoqu Ma, Huajie Xue, Zhaonan Yan, Junjie Chong, Daotong Wang, Jinshi State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jia Otong University Xi'an710049 China

In this paper, the boiler thermal system of a 600MW supercritical lignite-fired power plant was modeled and simulated with the application of GSE simulation software. The model was developed in Jtopmeret according to the structural features and divided into steam-water system, flue gas -air system, and direct-fired pulverizing system. Model simulations were implemented in SimExec. The outlet temperature of different devices and sections under BMCR and 75% THA conditions were compared with the reference data. The results show that the simulation model developed had high accuracy and reliability. Further simulations were carried out on the varied load. The boiler efficiency and flue gas extraction amount changed with the load.

关键词： Flue gases

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The quantum research on the aromaticity of polycyclic aromatic hydrocarbons

The quantum research on the aromaticity of polycyclic aromat...

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第七届国际分子模拟与信息技术应用学术会议

作者： Qingzhen Han Jinling Zhao Zhaotan Jiang Hao Wen State Key laboratory of Multiphase Complex System Institute of Process EngineeringChinese Academy o School of Physics Beijing Institute of TechnologyBeijingChina100081

Molecular aromaticity and the loss of conjugation in the polycyclic aromatic hydrocarbons (PAHs) are investigated using the restricted Hartree Fock (RHF) and Multi Reference Configuration Interaction (MRCI) method based on the average two-center indices (ATI) obtained from the electron *** the calculations were performed with the Gaussian 03 and Molpro2010 packages of *** is shown that the ATI values for the symmetry-unique rings decreasing from outer to inner rings both in cata-condensed and peri-condensed PAHs in the ground *** behavior of the aromaticity indices when going from the ground state to a low-lying excited state is also *** ATI values of symmetry-unique rings indicate a decreasing aromaticity going from the ground states to the excited states for cata-condensed PAHs, while it has a significant increase for some symmetry-unique rings of peri-condensed *** addition, it also can be found that the ATI value of benzene aromaticity will be close to zero, when it is in the superimposed state which composed of the ground state, the third and fourth excited *** means that in this state,benzene molecule is loss of its *** work aims at revealing the deepening loss-conjugation reasons and providing the theory basis for the research on problems of the nonaromatic superimposed state for the PAHs.

关键词： polycyclic aromatic hydrocarbons the ground state the excited state aromaticity loss of conjugation

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Direct reduction of hematite powders in a fluidized bed reactor

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Particuology 2013年第3期11卷 294-300页

作者： Qingshan Zhu Rongfang Wua Hongzhong Li State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of Sciences Graduate University of Chinese Academy of Sciences

Ultrafine hematite powder was reduced to produce ultrafine iron powder in a 50%Ar-50%H2 atmosphere at 450-550 ℃ in a fluidized bed reactor. The ultrafine hematite powder shows the typical agglomerating fluidization behavior with large agglomerates fluidized at the bottom of the bed and small agglomerates fluidized at the upper part of the bed. It was found that defluidization occurred even at the low temperature of 450 C with low metallization rate. Defluidization was attributed mainly to the sintering of the newly formed iron particles. Granuation was employed to improve the fluidization quality and to tackle the defluidization problem, where granules fluidized like a Geldart＇s group A powder. Granulation was found to effectively reduce defluidization during reduction, without however sacrificing reduction speed. The asreduced iron powders from both the ultrafine and the granulated hematite exhibited excellent sintering activity, that is, fast sintering at temperature of as low as ~580℃, which is much superior as compared to that of nano/ultrafine iron powders made by other processes.

关键词： Direct reduction Granulation Defluidization Sintering Ultrafine iron powder

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Solar receiver/reactor for hydrogen production with biomass gasification in supercritical water

Solar receiver/reactor for hydrogen production with biomass ...

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作者： Liao, Bo Guo, Liejin Lu, Youjun Zhang, Ximin State Key Laboratory of Multiphase Flow in Power Engineering Xi'An Jiaotong University Xi'an Shaanxi Province 710049 China

A novel receiver/reactor driven by concentrating solar energy for hydrogen production by supercritical water gasification (SCWG) of biomass was designed, constructed and tested. Model compound (glucose) and real biomass (corncob) were successfully gasified under SCW conditions to generate hydrogen-rich fuel gas in the apparatus. It is found that the receiver/reactor temperature increased with the increment of the direct normal solar irradiation (DNI). Effects of the DNI, the flow rates and concentration of the feedstocks as well as alkali catalysts addition were investigated. The results showed that DNI and flow rates of reactants have prominent effects on the temperature of reactor wall and gasification results. Higher DNI and lower feed concentrations favor the biomass gasification for hydrogen production. The encouraging results indicate a promising approach for hydrogen production with biomass gasification in supercritical water using concentrated solar energy. © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

关键词： Hydrogen production

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Investigation on catalyzed reactivities of synthetic model coal under oxy-fuel conditions by thermal analysis

Investigation on catalyzed reactivities of synthetic model c...

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9th Asia-Pacific Conference on Combustion, ASPACC 2013

作者： Wang, Chang'an Du, Yongbo Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 China

Oxy-fuel combustion is one of the near-zero emission clean coal technologies, which can realize large-scale CO2 capture. In this paper, catalyzed reactivities of synthetic model coal incorporating Fe 2O3, TiO2, and MnO2 under oxy-fuel conditions have been investigated using thermal analysis method. Experimental results show that all three catalysts present a certain extent catalytic action on the combustion behaviors of synthetic model coal under oxy-fuel conditions. The catalytic activity in main combustion process of model coal could be described as follows: Fe2O3 > TiO2 > MnO2. The increase of catalyst content causes the model coal combustion process to slightly shift to lower-temperature zone. The ignition temperature Ti shows almost no variation as Fe2O 3 or TiO2 is added into the samples. The catalysts present a not very obvious catalytic activity on the pyrolysis behaviors of synthetic model coal. In addition, TiO2 shows the greatest catalytic activity on the model coal gasification performance, while MnO2 plays an unfavorable role. The catalytic activity in gasification process of model coal could be described as follows: TiO2 > Fe2O3 > MnO2.

关键词： Coal

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A new model of selective photothermolysis to aid laser treatment of port wine stains

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Chinese Science Bulletin 2013年第3期58卷 416-426页

作者： LI Dong HE YaLing WANG GuoXiang WANG YongXian YING ZhaoXia State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Department of Mechanical Engineering The University of AkronAkron 44325-3903USA Department of Dermatology Medical School of Xi'an Jiaotong University

Pulsed dye lasers equipped with cryogen spray cooling(CSC) are now widely used to treat vascular malformation such as port wine stains(PWSs).This paper presents a new integrated model that can quantitatively simulate the cooling of the skin and the heating of the targeted blood vessels in PWSs during laser *** new model is based on the classical homogeneous multi-layer skin model that treats PWS-containing dermis as a mixture of dermal tissue and homogeneously distributed *** propagation in skin and PWSs is simulated by a Monte-Carlo method,which provides accurate description of the light scattering and absorption in the *** response of a targeted vessel in the new model is then obtained from the thermal analysis of a Krogh-unit that consists of the vessel and the surrounding dermal tissues and is buried in *** results from the multi-layer skin model provide appropriate laser influence input as well as the initial thermal condition for the micro-model of the Krogh-unit.A general dynamic relation is also introduced on the surface of skin to quantify the convective cooling of *** model is then applied to dye-laser treatment(wavelength of 585 nm) of PWSs with *** results demonstrate that the present model is able to quantify thermal response of a deeply buried blood vessel in PWSs as a discrete blood vessel does,with a more realistically estimate of the sheltering effect of the dermal tissue(scattering) and blood vessels(absorption) in front of the targeted *** understand the poor response of PWSs in clinic,the thermal characteristics of a targeted vessel was simulated under various *** effects of two morphological parameters,the vessel diameter and the burying depth of the vessel,are then systematically investigated under various pulse durations and fluences of laser.A threshold fluence for given vessel diameter and depth is then estimated quantitatively under the condition of the optimal laser pulse durat

关键词：激光治疗仪 Monte-Carlo方法鲜红斑痣脉冲持续时间激光能量密度热作用皮肤组织集成模型

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Unified stability condition for particulate and aggregative fluidization—Exploring energy dissipation with direct numerical simulation

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Particuology 2013年第2期11卷 232-241页

作者： Min Wei Limin Wang Jinghai Li The EMMS Group State Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringChinese Academy of Sciences University of Chinese Academy of Sciences

Fully resolved simulations of particulate and aggregative fluidization systems are performed suc-cessfully with the so-called combined lattice Boltzmann method and time-driven hard-sphere model （LBM-TDHS）. In this method, the discrete particle phase is described by time-driven hard-sphere model, and the governing equations of the continuous fluid phase are solved with lattice Boltz-mann method. Particle-fluid coupling is implemented by immersed moving boundary method. Time averaged flow structure of the simulated results show the formation of core-annulus structure and sigmoid distribution of voidage in the axial direction, which are typical phenomena in fluidization systems. Combining the results of the simulation, the energy consumption Nst for suspending and transporting solids is calculated from the direct numerical simulation （DNS） of fluidization, and the stability criterion Nst/NT = rain proposed in EMMS/bubbling model is verified numerically. Further-more the numerical results show that the value of Nst/NT in particulate fiuidization is much higher than that in aggregative fluidization, but Nst/NT = rain is effective for both particulate and aggregative fluidization.

关键词： Direct numerical simulation Fluidization Stability condition Lattice-Boltzmann method Time-driven hard-sphere model

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Ni/Al_2O_3 catalysts for CO methanation: Effect of Al_2O_3 supports calcined at different temperatures

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Journal of Energy Chemistry 2013年第6期22卷 919-927页

作者： Jiajian Gao Chunmiao Jia Jing Li Meiju Zhang Fangna Gu Guangwen Xu Ziyi Zhong Fabing Su State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences University of Chinese Academy of Sciences Institute of Chemical Engineering and Sciences A*star

The correlation between phase structures and surface acidity of Al2O3 supports calcined at different temperatures and the catalytic performance of Ni/Al2O3 catalysts in the production of synthetic natural gas(SNG) via CO methanation was systematically investigated. A series of 10 wt% NiO/Al2O3 catalysts were prepared by the conventional impregnation method, and the phase structures and surface acidity of Al2O3 supports were adjusted by calcining the commercial γ-Al2O3 at different temperatures(600–1200 C). CO methanation reaction was carried out in the temperature range of 300–600 C at different weight hourly space velocities(WHSV = 30000 and 120000 mL·g-1h-1) and pressures(0.1 and 3.0 MPa). It was found that high calcination temperature not only led to the growth in Ni particle size, but also weakened the interaction between Ni nanoparticles and Al2O3 supports due to the rapid decrease of the specific surface area and acidity of Al2O3 supports. Interestingly, Ni catalysts supported on Al2O3 calcined at 1200 C(Ni/Al2O3-1200) exhibited the best catalytic activity for CO methanation under different reaction conditions. Lifetime reaction tests also indicated that Ni/Al2O3-1200 was the most active and stable catalyst compared with the other three catalysts, whose supports were calcined at lower temperatures(600, 800 and 1000 C). These findings would therefore be helpful to develop Ni/Al2O3 methanation catalyst for SNG production.

关键词： Ni catalyst alumina CO methanation synthetic natural gas carbon deposition

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Continuous hydrogen production by biomass gasification in supercritical water heated by molten salt flow: System development and reactor assessment

Continuous hydrogen production by biomass gasification in su...

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作者： Xiao, Peng Guo, Liejin Zhang, Ximin Zhu, Chao Ma, Shaohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'An Jiaotong University Xi'an 710049 Shaan Xi Province China

Hydrogen production by biomass gasification using solar energy is a promising approach for overcoming the drawbacks of fossil fuel utilization, but the storage of discontinuous solar flux is a critical issue for continuous solar hydrogen production. A continuous hydrogen production system by biomass gasification in supercritical water using molten-salts-stored solar energy was proposed and constructed. A novel double tube helical heat exchanger was designed to be molten salts reactor for hydrogen production. Model compounds (glycerol/glucose) and real biomass (corn cob) were successfully gasified in this molten salts reactor for producing hydrogen-rich gas. The unique temperature profiles of biomass slurry in the reactor were observed and compared with that of conventional electrical heating and direct solar heating approaches. Product gases yield, gasification efficiency and exergy conversion efficiency of the reactor were analyzed. The results showed that the performances of reactor were determined by feedstock style, biomass concentration, residence time and biomass slurry temperature profiles. © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

关键词： Biomass

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Diffusion-reaction compromise the polymorphs of precipitated calcium carbonate

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Particuology 2013年第3期11卷 301-308页

作者： Han Wang Wenlai Huang Yongsheng Han EMMS Group State Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringChinese Academy of Sciences Graduate School of Chinese Academy of Sciences

Diffusion is seldom considered by chemists and materialists in the preparation of materials while it plays an important role in the field of chemical engineering. If we look at crystallization at the atomic level, crystal growth in a solution starts from the diffusion of ions to the growing surface followed by the incorporation of ions into its lattice. Diffusion can be a rate determining step for the growth of crystals. In this paper, we take the crystallization of calcium carbonate as an example to illustrate the microscopic processes of diffusion and reaction and their compromising influence on the morphology of the crystals produced. The diffusion effect is studied in a specially designed three-cell reactor. Experiments show that a decrease of diffusion leads to retardation of supersaturation and the formation of a continuous concen- tration gradient in the reaction cell, thus promoting the formation of cubic calcite particles. The reaction rate is regulated by temperature. Increase of reaction rate favors the formation of needle-like aragonite particles. When diffusion and reaction play joint roles in the reaction system, their compromise dominates the formation of products, leading to a mixture of cubic and needle-like particles with a controllable ratio. Since diffusion and reaction are universal factors in the preparation of materials, the finding of this paper could be helpful in the controlled synthesis of other materials.

关键词： Calcium carbonate Shape control Crystallization Diffusion Compromise

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