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Particuology 2021年第2期19卷 1-15页

作者： Haidong Zhang Zeneng Sun Chengguo Liu Shurui Dong Yuanyuan Shao Jesse Zhu Collaborative Innovation Center of Chemical Science and Engineering(Tianjin) School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072PR China Particle Technology Research Centre Department of Chemical&Biochemical EngineeringThe University of Western OntarioLondonOntario N6A 5B9Canada

The effects of internals and gas distributors on the local dynamics of the bubbles in the conventional gas-solid fluidized bed were ***-type internals with different opening areas(50%,70%and 90%)and different arrangements(two-layer and four-layer);and a sintered plate with a smaller pore size(1μm)and a perforated plate with a larger pore size as distributors were *** pressure drops and local solids holdups were measured under various superficial gas velocities to compare the performances of the different types of internals and *** instantaneous solids holdup signals from the optical fibre probe were used to further examine the local bubble dynamics in *** bubbles were found,with the installation of internals or using the sintered plate,resulting in lower pressure drops and a higher bed *** with reduced opening area or distributor with smaller pore size further leads to a higher changeover rate between the bubbles and dense phase,both axially and radially,and hence a better gas-solid contacting and an earlier transition to the turbulent flow regime of the bed.

关键词： gas-solid fluidized bed Internal gas distributor Bubble dynamics Flow regime transition

Effect of promoters on dynamics of gas-solid fluidized bed——Statistical and ANN approaches

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China Particuology 2007年第6期5卷 401-407页

作者： Y.K. Mohanty K.C. Biswal G.K. Roy B.P. Mohanty Department of Chemical Engineering GIET Gunupur 765 022 Rayagada Orissa India Department of Chemical Engineering NIT Rourkela 769008 Orissa India

In this study, a bubbling fluidized bed column, 99 mm in inside diameter and 960 mm in height, was used to investigate the effect of rod and disc promoters on fluctuation and expansion ratios. Factorial design （statistical approach） and artificial neural network （ANN） models were developed to predict the fluctuation and expansion ratios in this gas-solid fluidized bed with varying gas flow rates, bed heights, particle sizes and densities. The fluctuation and expansion predicted using these statistical and ANN models, for beds with and without promoters, were found to agree well with corresponding experiments. The statistical model was found to be superior to the ANN model due to its ability to take into account both individual and interactive effects. The rod promoters were found to be more effective in reducing bed fluctuation, and in increasing bed expansion at high gas mass velocities.

关键词： gas-solid fluidized bed Fluctuation ratio Expansion ratio Promoter Factorial design Artificial neural network

EMMS drag model for simulating a gas-solid fluidized bed of geldart B particles: Effect of bed model parameters and polydisperity

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Particuology 2020年第4期18卷 142-154页

作者： Krishnadash SKshetrimayum Seongho Park Chonghun Han Chul-Jin Lee School of Chemical Engineering and Materials Science Chung-Ang University06974 SeoulSouth Korea School of Chemical and Biological Engineering Seoul National UniversitySan 56-1Shillim-dongKwanak-guSeoul151-742South Korea

The energy minimization multi-scale(EMMS)is a heterogeneous drag model widely used to simulate gas-solid fluidized *** this work,we conducted computational fluid dynamics simulations of a gas-solid fluidized bed for Geldart B particles to compare the EMMS with the homogeneous Gidaspow drag *** results from both the homogeneous and heterogeneous drag models were compared with literature experimental data on pressure drop and bed *** was no noticeable difference in predicted bed characteristics in the slugging ***,in the turbulent regime,the EMMS model predicted slightly lower bed expansion than did the Gidaspow *** evaluated the effects of solid-solid and solid-wall interaction parameters by varying the restitution and specularity *** expansion increases by a factor of 1.05-1.08 when the restitution coefficient increases from 0.9 to *** models predict a higher solid volume fraction and higher solid downflow velocity near the wall for a low specularity coefficient of 0.01 or *** we considered solid phases of different sizes to model polydisperity,the simulation predicted vertical segregation of 300,350,and 400μm in the fluidized region due to ***,the drag models made similar predictions in bad characteristics from cold model simulation ofa polysilicon fluidized-bed reactor,although there was very little vertical segregation of solid particles for this case.

关键词： CFD simulation Energy minimization multi-scale drag gas-solid fluidized bed Polydisperity fluidized-bed reactor

Validation of an improved two-fluid model with particle rotation for gas-solid fluidized bed

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Particuology 2023年第10期81卷 149-161页

作者： Lian Wang Xihua Chu School of Civil Engineering Wuhan UniversityWuhan430072HubeiChina

gas-solid fluidized beds are widely applied in chemical and process *** is of significance to establish a reasonable and effective mathematical model to explore the hydrodynamics of gas-particle system for industrial *** a less computationally demanding alternative to the discrete descriptions,two-fluid model considering kinetic theory of granular flow is often adopted to describe the fluidized behaviors of particles,but it cannot characterize the rotation of particles and its influence on the fluidized *** this study,to address the rotation effect of the fluidized particles,a two-fluid model combining the classical fluid and micropolar fluid is established,namely *** the CMTFM,classical fluid is used to describe the motion of gas phase,while micropolar fluid is adopted to describe the motion of particle phase,and the rotation of particles and its influence on the hydrodynamics of the gas-particle system are characterized by the degree of freedom of microrotation and the improved drag force based on micropolar *** the calculation of the gas-solid bubbling fluidized bed,we investigated the influence of the microstructure parameters,particle-particle collision restitution coefficient and inlet velocity,and the results are compared to those from TFM model and *** the analysis,it manifests that pressure drop and expansion height of the fluidized bed under the consideration of the microrotation effect are closer to the experiments,which demonstrates the feasibility and advantage of the classical-micropolar two-fluid model.

关键词： gas-solid fluidized bed Two-fluid model Micropolar fluid Microstructure parameter fluidized behaviors

CFD simulation of pressure fluctuation characteristics in the gas-solid fluidized bed:Comparisons 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 College Guizhou University Guiyang 550025 China

A simple hydrodynamic model based on two-fluid theory, taking into account 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 commercial 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

Modularized dry coal beneficiation technique based on gas-solid fluidized bed

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Journal of Central South University 2011年第2期18卷 374-380页

作者：赵跃民李功民骆振福梁春成唐利刚陈增强邢洪波 School of Chemical Engineering and Technology China University of Mining and Technology Tangshan Shenzhou Manufacturing Co. Ltd. State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of Sciences

A 40-60 t/h modularized dry coal beneficiation process with a novel method to control the bed was designed around a gas-solid fluidized bed separator. Furthermore, the hydrodynamics of medium-solids consisting of wide-size-range magnetite powder （0.3-0.06 ram） and 〈1 mm fine coal were numerically studied. The simulation results show that the fluidization performance of the wide-size-range medium-solid bed is good. The separation performance of the modularized system was then investigated in detail using a mixture of 〈0.3 mm magnetite powder （mass fraction of 0.3-0.06 mm particles is 91.38 %） and 〈1 mm fine coal as solid media. The experimental results show that at separation densities of 1.33 g/cm^3 or 1.61 g/cm^3, 50-6 mm coal can be separated effectively with probable error, E, values of 0.05 g/cm^3 and 0.06 g/cm^3, respectively. This technique is beneficial for saving water resources and for the clean utilization of coal.

关键词： dry coal beneficiation modularization gas-solid fluidized bed wide-size-range medium-solids

Simulation of gas-solid fluidized bed reactor for F-T synthesis

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Journal of Coal Science & Engineering(China) 2009年第4期15卷 420-425页

作者： CAI Jin LI Tao SUN Qi-wen YING Wei-yong FANG Ding-ye Engineering Research Center of Large Scale Reactor Engineering and Technology Ministry of Education State Key Laboratory of Chemical Engineering East China University of Science and Technology Shanghai 200237 China State Key Laboratory of Coal Liquefaction and Coal Chemical Technology Shanghai 201203 China

Using the lumping method, CH_4, C_3H_8, C_10H_22, and C_22H_44 were chosen as themodel products, and CO as the key component. The mathematical model of a gas-solidfluidized bed reactor was established based on some hypotheses. The consumption kinetic model of CO was investigated, and the parameters were estimated by UniversalGlobal Optimization with the Marquardt method. Residual error distribution and a statisticaltest show that the intrinsic kinetic models are reliable and acceptable. A model of carbonchain growth probability was established in terms of experiments. Coupled with the Ander-son- Schulz-Flory (ASF) distribution, the amount of specific product could be ***- scale cold model experiments were conducted to investigate the distribution of thegas (solid) phase and determine the function of the voidage with the location of the catalytic bed. The change tendencies of the components in the catalytic bed at different temperatures were computed and figured out. The calculated value computed by the modelestablished for the Fe-based F-T synthesis catalyst fit the experimental value very wellunder the same operating conditions, and all the absolute values of the relative deviationsare less than 5%.

关键词： gas-solid fluidized bed F-T synthesis reactor lumping

CFD simulation of jet behaviors in a binary gas-solid fluidized bed:comparisons with experiments

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Frontiers of Chemical Science and Engineering 2010年第3期4卷 242-249页

作者： Pei PEI Guiying WU Kai ZHANG Bangting YU Jianchun JIANG Dongsheng WEN State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing 102249China National Engineering Laboratory for Biomass Power Generation Equipment North China Electric Power UniversityBeijing 102206China Institute of Chemical Industry of Forest Products Chinese Academy of ForestryNanjing 210042China School of Engineering and Materials Science Queen Mary University of LondonLondon E14NSUK

Based on the experimental observation of the fluidization characteristics of solid mixtures(resin and rapeseed)with different densities and sizes,the jet behaviours of the binary system are simulated in a twodimensional jetting fluidized bed 0.30m in width and 2.00m in height.A simple mathematical model,by introducing two additional force terms in both gas and particle phase momentum equations of Gidaspow’s inviscid two-fluid model,is used to explore the effects of jet gas velocity and mixture combination on the jet penetration depth in the fluidized bed with a binary *** results show that there is a fluidization velocity interval(u_(if)-u_(ff))for the resin-on-rapeseed(flotsam-on-jetsam)segregated *** simulated jet penetration depth increases with the increase of jet gas velocity and the volume fraction of the flotsam(resin),which is in fair agreement with experimental *** above findings show that the hydrodynamic model of Brandani and Zhang(2006),by introducing the average physical properties from Goossens et al.(1971),can be used to predict the jet behaviors of a well-mixing binary system.

关键词： gas-solid fluidized bed binary mixture jet behavior

Multi-scale Analysis of Chaotic Characteristics in a gas-solid fluidized bed

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Chinese Journal of Chemical Engineering 2002年第3期10卷 358-362页

作者：甄玲王晓萍陈伯川黄海黄春艳 Instrument Department Zhejiang University Hangzhou 310027 Chemical Engineering Department Zhejiang University Hangzhou 310027

Deterministic chaos theory offers useful quantitative tools tocharacterize the non-linear dynamic be- havior of a fluidized bed andthe developed complexity theory presents a new approach to evaluatefinite sequences. In this paper, the non-linear, hydrodynamicbehavior of the pressure fluctuation signals in a reactor wasdiscussed By chaos parameters and complexity measures. Coherentresults were achieved by our multi-scale analysis, which Furtherexposed the behavior in a gas-solid two-phase system.

关键词： gas-solid fluidized bed pressure fluctuation chaotic theory complexitytheory

Wavelet Characterization of the Flow Regime in a gas-solid fluidized bed

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Journal of Energy and Power Engineering 2013年第6期7卷 1023-1031页

作者： Maria Luiza Sperb Indrusiak Yesid Javier Rueda-Ordonez Arai Augusta Bernardez Pecora Mechanical Engineering Department Polytechnic School University of Vale do Rio dos Sino-UNISINOS Porto Alegre93022-000 Brazil Department of Thermal and Fluids Engineering School of Mechanical Engineering University of Campinas-UNICAMPCampinas 13083-860 Brazil

Processes like combustion, pyrolysis or gasification of coal and biomass are typical applications of gas-solid fluidized beds. These reactors normally use silica sand as the inert material inside the bed and the sand particles represent around 95% of the total bed weight. Pressure measurements have been used to characterize the dynamic behavior of fluidized beds since early researches in the area. Pressure fluctuations are generally due to bubbles flow which characterizes the fluidization regime. The present work aims to perform a time-frequency analysis of the pressure signal acquired in an experimental apparatus on different gas-solid flow regimes. Continuous and discrete wavelet transforms were applied and the results were compared with image records acquired simultaneously with the pressure signal. The main frequencies observed are in accordance with the ones obtained through Fourier spectra. The time-frequency distribution of the signal agrees with the phenomena observed in the image record, remarkably for the slugging flow. Some additional research is still necessary to completely characterize the flow regimes using the wavelet scalograms but the present results show that the task is a very promising one.

关键词： gas-solid fluidized bed wavelet pressure fluctuations.