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CFD simulation of pressure fluctuation characteristics in the gas-solid fluidized bed:co.parisons with experiments

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Petroleum Science 2011年第2期8卷 211-218页

作者： Wang Qingcheng zhang Kai Gu Hongyan Beijing Shenwu Thermal Energy Technology co. LTD Beijing 102200 China State Key Laboratory of Heavy Oil Processing China University of Petroleum Beijing 102249 China National Engineering Lab for Biomass power Generation Equipment North China Electric Power University Beijing 102206 China Electrical Engineering co.lege Guizhou University Guiyang 550025 China

A simple hydrodynamic model based on two-fluid theory, taking into acco.nt the effect of discrete particles on both the gas- and solid-phase momentum equations, was used to numerically investigate the pressure fluctuation characteristics in a gas-solid fluidized bed with the aid of CFX 4.4, a co.mercial CFD software package, by adding user-defined Fortran subroutines. Numerical simulations together with typical experimental measurements show that pressure fluctuations originate above the distributor when a gas pulse is injected into the fluidized bed. The pressure above the bubble gradually increases due to the presence of a rising bubble. When the bubble passes through the bed surface, the pressure near the bed surface gradually decreases to a lower value. Moreover, the pressure signals in the bubbling fluidized beds show obviously periodic characteristics. The major frequency of pressure fluctuations at the same vertical position is affected slightly by the operating gas velocity, and the amplitude of pressure fluctuations is related to both the operating gas velocity and the vertical height. In this study, the influence of the operating gas velocity on the pressure wave propagation velocity can be ignored, and only two peak frequencies in the power spectrum of the pressure fluctuations are observed which are associated with the bubble formation above the distributor and its eruption at the bed surface.

关键词： Gas-solid fluidized bed CFD simulation experimental measurements propagation ofpressure fluctuations pressure wave velocity pressure fluctuation frequency

A co.PLED THERMO-HYDRAULIC MODEL FOR STEAM FLOW IN PIPE NETWORKS

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Journal of Hydrodynamics 2009年第6期21卷 861-866页

作者： LIU Qing-tang zhang Zeng-gang PAN Ji-hong GUO Jing-qiang School of Energy Source and power Engineering Shandong University Jinan 250061 China School of Thermal power Engineering Shandong Jianzhu University Jinan 250101 China Yishui Municipal Engineering co. Yishui 276400 China

This article aims to establish a co.pled thermo-hydraulic mathematical model for steam network by adopting a set of equations, i.e., the co.tinuity equation, motion equation, energy equation, state equation and enthalpy equation and co.sidering the interaction of hydraulic and thermal working co.ditions. The model is simplified acco.ding to steam flow features in pipe networks. The unsteady flow model is simplified to a steady one with co.sidering engineering practice and the solution to the governing equations are obtained by using the standard fourth-order Runge-Kutta method. Many factors of steam flow are generally co.sidered, such as co.densability, change of state, friction and heat transfer in the model. It is co.cluded that co.pled iteration can be employed in steam network thermo-hydraulic co.putation. The numerical results with the model are basically in acco.dance with practical operation data.

关键词： steam flow thermo-hydraulic co.pling mathematical model hydraulic calculation

power Production Management of Three Gorges Project

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Electricity 2010年第2期21卷 41-44页

作者： zhang Cheng General Manager of china Yangtze power co., Ltd General Manager of china Yangtze power co. Ltd

The Three Gorges Hydropower Plant is the one with the largest installed capacity in the world today and has a decisive and important influence upon the security of the national power grids. It has been operated stably and supplied the East china, Central china, South china, Sichuan and Chongqing with clean renewable energy. This paper presents the management of the project’s dispatch, operation and maintenance and puts forward new ideas and new methods for the plant management, which may provide valuable references for the operation of oversized hydropower plants.

关键词： power Production Management of Three Gorges Project

Running co.trol Mode for In-Duct FGD with No-Bypass Design

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Electricity 2010年第3期21卷 51-54页

作者： Li Qing,Mao Yongqing,zhang Chaoyang,Huang Bo,Zhu Xianran north china Electric power Research Institute co.,Ltd north china Electric power Research Institute co. Ltd

The desulfuration system in the seco.d phase project of Sanhe power Plant is the first such system that adopts in-duct FGD with no-bypass design by domestic power *** from that of the co.ventional FGD with bypass design,a running co.trol mode,which is important for the security of the absorbing tower within the designed ranges,shall be made to ensure the flue gas temperature and dust co.centration at the inlet of the absorbing *** stable running of the system shows that the co.trol mode is feasible.

关键词： in-duct FGD gas flue with no-bypass design operation co.trol

From waste to wealth:co.l tar residue derived carbon materials as low-co.t anodes for potassium-ion batteries

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 464-475页

作者： Zhonghua Lu Jun Shen Xin zhang Lingco.g Chao Liang Chen Ding zhang Tao Wei Shoudong Xu co.lege of Chemical Engineering and Technology Taiyuan University of TechnologyTaiyuan 030024China co.lege of Chemistry Taiyuan University of TechnologyTaiyuan 030024China School of Chemical Engineering and Pharmacy Wuhan Institute of TechnologyWuhan 430205China School of Energy and power Jiangsu University of Science and TechnologyZhenjiang 212003China

Carbon materials are widely reco.nized as highly promising electrode materials for various energy storage system *** tar residues(CTR),as a type of carbon-rich solid waste with high value-added utilization,are crucially important for the development of a more sustainable *** this study,we employed a straightforward direct carbonization method within the temperature range of 700-1000℃to co.vert the worthless solid waste CTR into eco.omically valuable carbon materials as anodes for potassium-ion batteries(PIBs).The effect of carbonization temperature on the microstructure and the potassium ions storage properties of CTR-derived carbons(CTRCs)were systematically explored by structural and morphological characterization,alongside electrochemical performances *** on the co.regulation between the turbine layers,crystal structure,pore structure,functional groups,and electrical co.ductivity of CTR-derived carbon carbonized at 900℃(CTRC-900H),the electrode material with high reversible capacity of 265.6m Ah·g^(-1)at 50 m A·g^(-1),a desirable cycling stability with 93.8%capacity retention even after 100 cycles,and the remarkable rate performance for PIBs were ***,cyclic voltammetry(CV)at different scan rates and galvanostatic intermittent titration technique(GITT)have been employed to explore the potassium ions storage mechanism and electrochemical kinetics of *** indicate that the electrode behavior is predominantly governed by surface-induced capacitive processes,particularly under high current densities,with the potassium storage mechanism characterized by an“adsorption-weak intercalation”*** work highlights the potential of CTR-based carbon as a promising electrode material category suitable for high-performance PIBs electrodes,while also provides valuable insights into the new avenues for the high value-added utilization of CTR.

关键词： co.l tar residue carbon materials anode potassium-ion batteries high value-added

A novel method for the improvement of power efficiency in high peak-to-average-power ratio co.munication systems

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Science china(Information Sciences) 2010年第8期53卷 1697-1702页

作者： REN ZhiYuan 1 , zhang HaiLin 1 & GUO Kai 2 1 State Key Laboratory of Integrated Services Network, Xidian University, Xi’an 710071, china 2 Aerospace Long March Launch Vehicle Technology co. Ltd., Beijing 100076, china State Key Laboratory of Integrated Services Network Xidian University Xi’an China Aerospace Long March Launch Vehicle Technology co. Ltd. Beijing China

To solve the problem of low power efficiency of power amplifiers (PA) in the high peak-to-averagepower ratio (PAPR) co.munication system, a novel signal deco.posed amplifier structure has been proposed in order to decrease the energy co.sumption and increase the power efficiency of PA. The high PAPR signal can be deco.posed into several low PAPR branch signals, linearized and amplified in parallel. This structure can reduce the PAPR of branch signals and improve the power efficiency of PA. The simulation results indicate that the power efficiency will be remarkably increased.

关键词： Green Radio power amplifier signal deco.posed

Implementation of PMUs from the Viewpoint of Space-time co.perative

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Implementation of PMUs from the Viewpoint of Space-time Coop...

Preparation and Magnetic Properties of Mn-Zn Ferrites by the co.precipitation Method

2011 International co.ference on Advanced power System Automation and Protection(APAP 2011)

作者： WANG Liang 1 , zhang DaoNong 2 1 NARI-RELAYS Electric co.,LTD, Nanjing 211102, china 2 north china power Engineering co.LTD, Beijing 100120, china

This paper proposes the implementation of PMUs from the viewpoint of space-time co.perative. Observability and co.trollability are the goals of large-scale system. Data from SCADA, PMU or anything else should serve these two purposes. The synchronized data from PMUs is the fundamental source for observation and co.trol of power system in a certain level. PMU is not necessarily a dedicate device and any IED has the capability of synchronize sampling co.ld be a sort of PMU which offering synchronize data. That is mean the PMU is a function module other than a dedicate device. The protection, bay co.trol unit, fault reco.der and stability co.trol device are all the data sources of synchronized phasor measurement if they can provide the data of synchrophasor. A certain observation and co.trol of power system implement in the certain time scale（10ms level or more） and space scale（220kV substations or more） from the PMUs or any other IEDs. So the function of PMUs should be reco.sidered in the space-time framework of power system. The practices provide the evidence for this.

关键词： monitoring stability co.trols wide-area protection

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Journal of Wuhan University of Technology(Materials Science) 2009年第6期24卷 875-878页

作者：李雪张俊喜 School of Environmental and Chemical Engineering Shanghai University Electrochemical Research Group Shanghai University of Electric PowerKey Laboratory of State Power Corporation of China

Mn-Zn ferrites （Mn1-xZnxFe2O4） with different co.positions were prepared by the co.recipitation method, and the influences of such synthesis co.ditions as pH value, co.position and volume ratio （R） of the mixed solution and NH4Hco. solution on their microstructures and magnetic properties were discussed. The samples were characterized by X-ray diffraction （XRD） and magnetization measurement instrument. Lattice parameters and average crystalline size of the synthesized materials were calculated from the co.responding XRD patterns with the related software Jade.5. For samples of different pH values, only one phase was found when pH values were 7.0, 8.0 and 9.0. The sample with pH value of 7.0 exhibited the highest saturation magnetic induction, the lowest co.rcive force, and crystallized best. For samples of different R values with pH value of 7.0, only one phase was observed in all samples, and the sample with R value of 2.3 exhibited the highest saturation magnetic induction and the lowest co.rcive force. The co.position has mainly afected the magnetic properties, and the saturation magnetic induction increases with the increase of the co.tent of Zn （x）, but decreases when x is beyond 0.6. The trend of co.rcive force is on the co.trary. However, no magnetism is exhibited when the x value is up to 0.8.

关键词： co.precipitation method microstructure magnetic property Mn-Zn ferrite

co.2 Mitigation in co.l Gasification co.eneration Systems with Integration of the Shift Reaction, co.2 Absorption and Methanol Production

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Journal of Thermal Science 2004年第3期13卷 193-198页

作者： Yuanyuan DUAN Jin zhang Key Laboratory of Thermal Science and power Engineering, Department of Thermal Engineering, Tsinghua University, Beijing 100084, china Key Laboratory of Thermal Science and power Engineering Department of Thermal Engineering Tsinghua University Beijing China

co.eneration of electricity and liquid fuel can achieve higher efficiencies than electricity generation alone in Integrated Gasification co.bined Cycle (IGCC), and co.eneration systems are also expected to mitigate co. emissions. A proposed methanol-electricity co.eneration system was analyzed in this paper using exergy method to evaluate the specified system. A simple co.eneration scheme and a co.plicated scheme including the shift reaction and co. removal were co.pared. The results show that the co.plicated scheme co.sumes more energy, but has a higher methanol synthesis ratio with partial capture of *** those methanol and electricity co.eneration systems, the co. mitigation is not merely an additional process that co.sumes energy and reduces the overall efficiency, but is integrated into the methanol production.

关键词： co.eneration system methanol synthesis co. mitigation exergy analysis