检索结果-南通市图书馆

Journal of Thermal Science 2023年第5期32卷 1797-1806页

作者： DENG Boyu ZHANG Man WEI Guohua LYU Junfu yang hairui State Key Laboratory of Power System and Generation Equipment Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China State Key Laboratory of Efficient and Clean Coal-fired Utility Boilers/Harbin Boiler Company Limited Harbin 150046China

Controversies still exist over the necessity of equipping with an emergency water supply system in the supercritical circulating fluidized bed/CFB *** resolve the dispute,research on the safety of the heating surfaces in the supercritical CFB boiler during the electricity failure accident under the assumption of not putting the emergency water supply system into use must be ***,due to the low incidence rate of this accident,no relevant data have been reported *** provide useful data for the related research,a breakdown accident of the main feed water pump that happened in a 350 MW supercritical CFB boiler was introduced in this *** analysis of the physical processes in both the furnace and water side of the boiler during this accident was *** the discussion on the similarities and discrepancies between the two accidents was carried *** was found out that with appropriate handling,the data collected in two periods of the breakdown accident of the main feed water pump can provide a reference for the verification of the prediction model of the electricity failure ***,a preliminary prediction model was established as the first step of the verification work.

关键词： supercritical CFB water supply cut off electricity failure accident analysis

Effect of operational and geometric parameters on the hydrodynamics of a Wurster coater:A CFD-DEM study

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第2期85卷 62-76页

作者： Yinqiang Song Tuo Zhou Ruiqi Bai Man Zhang hairui yang Department of Energy and Power Engineering Tsinghua UniversityBeijing100084China Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua UniversityBeijing100084China State Key Laboratory of Power System and Generation Equipment Tsinghua UniversityBeijing100084China

A coupled CFD-DEM method was used to study the hydrodynamics of a Wurster ***,the CFD part of the model was validated by the accurate prediction of the pressure drops over a pseudo-2D fluidized bed under various gas *** effect of gas velocity,gap height,tube length and batch volume of the particles on the cycle time and the residence time of the particles was thoroughly *** central jet gas velocity ui was found to speed up the particle cycle but undermine the coating *** gas velocity at the horizontal transport zone u2 was able to promote the horizontal transport of the particles but should not be too high,otherwise,it would obstruct the normal falling back of the particles in the downward *** gap heights would decrease the coating efficiency but tube length had little impact on *** increment of batch volume would commonly abase the cycle time and the working efficiency under a given *** de-fluidization problem arose when the batch volume increased to 550 ***,this problem could be swept out by the optimization of u1 and *** a mixture of different sizes,the coarse particles enjoyed higher coating efficiency and could travel closer to the *** may shield the fine particles from getting enough coating liquids,and thus coarse particles and fine particles were not recommended to get coated in the same batch.

关键词： Numerical simulation CFD-DEM Wurster coater Hydrodynamics Cycle time Residence time

Numerical study on maldistribution of gas-solid flow in multiple-branching limestone-conveying pipelines of circulating fluidized bed

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2019年第5期17卷 14-21页

作者： Shahong Zhu Man Zhang Juanli Zhang Junfu Lyu hairui yang Key Laboratory for Thermal Science and Power Engineering of Ministry Education State Key Laboratory of Power Systems Department of Energy and Power Engineering. Tsinghua University. Beijing 100084 China

As one of the most important auxiliary systems of a circulating fluidized bed boiler,the limestone pneumatic conveying system is of great significance to its *** of powder in the different injecting ports seriously limits inner-furnace desulfurization performance owing to inefficient mixing of limestone powder and *** gas-solid flow characteristics of an industrial-scale multiple-branching limestone-conveying pipeline system of a 200 MW circulating fluidized bed boiler were studied using a computational particle fluid dynamics *** maldistribution intensity was studied under different operating conditions of air velocity and particle mass flow *** results indicated that when the air velocity increased,the maldistribution was mitigated,but when the particle mass flow rate increased,the maldistribution *** solve this problem,two improved schemes were proposed:adding a deflector at different angles and changing the height of pipeline *** to the simulation,the maldistribution could be efficiently mitigated using a distributor height in the range of 100-120 mm and a deflector angle of 10°-30°.

关键词： Circulating fluidized bed Limestone Pneumatic conveying Multiple-branching pipeline Maldistribution

Classification performance of model coal mill classifiers with swirling and non-swirling inlets

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2020年第3期28卷 777-784页

作者： Lele Feng Hai Zhang Lilin Hu yang Zhang Yuxin Wu Yuzhao Wang hairui yang Department of Energy and Power Engineering Tsinghua UniversityBeijing 100084China Chengde Petroleum College Chengde 067000China

The classification performance of model coal mill classifiers with different bottom incoming flow inlets was experimentally and numerically *** flow field adjacent to two neighboring impeller blades was measured using the particle image velocimetry *** results showed that the flow field adjacent to two neighboring blades with the swirling inlet was significantly different from that with the non-swirling *** the swirling inlet,there was a vortex located between two neighboring blades,while with the nonswirling inlet,the vortex was attached to the blade *** vorticity of the vortex with the non-swirling inlet was much lower than that with the swirling *** classifier with the non-swirling inlet demonstrated a larger cut size than that with the swirling inlet when the impeller was stationary(~0 r·min-1).As the impeller rotational speed increased,the cut size of the cases with non-swirling and swirling inlets both decreased,and the one with the non-swirling inlet decreased more *** values of the cut size of the two classifiers were close to each other at a high impeller rotational speed(≥120 r·min-1).The overall separation efficiency of the classifier with the non-swirling inlet was lower than that with the swirling inlet,and monotonically increased as the impeller rotational speed *** the swirling inlet,the overall separation efficiency first increased with the impeller rotational speed and then decreased when the rotational speed was above 120 r·min-1,and the variation trend of the separation efficiency was more *** the initial particle concentration increased,the cut sizes of both swirling and non-swirling inlet cases decreased first and then barely *** a low initial particle concentration(b 0.04 kg·m-3),the classifier with the swirling inlet had a larger cut size than that with the non-swirling inlet.

关键词： Coal mill classifier Cut size Non-swirling inlet Particle image velocimetry Impeller rotational speed

Experimental study on the angle of repose of pulverized coal

在线全文

学校读者我要写书评

暂无评论

Particuology 2010年第5期8卷 482-485页

作者： Wei Wang Jiansheng Zhang Shi yang Hai Zhang hairui yang Guangxi Yue Department of Thermal Engineering Tsinghua University Beijing 100084 PR China

An experimental study on the angle of repose （AoR） of pulverized coal with different particle sizes and different moisture contents （MC） was conducted. Three different measurement methods, free-base piling, fixed-base piling and sliding, were used. The data were analyzed by one-way and two-way analysis of variance. The results showed that the AoRs of pulverized coal with particle sizes smaller than 150 μm were in the range of 30-50°. The characterization of the flowability of pulverized coal was some cohesiveness or true cohesiveness. The increase of MC will increase AoR and thus decrease the flowability of the powder. However, the particle size effect is bifurcated. Below a critical size, the decrease of particle size decreases the flowability; while above the critical size, the decrease of particle size increases the flowability. It was found that the value of the critical size strongly depends on the powder density. Moreover, the AoR dependence on particle size could be linked with the Geldart＇s particle classification. The critical size at the turning point is on the boundary between Group A and Group B in Geldart＇s classification diagram. Based on the experimental results, there is no significant cross interaction between particle size and MC. The AoRs measured by free-base method and fixed-base method are close, but both remarkably smaller than that measured by the sliding method.

关键词： Angle of repose (AoR)Pulverized coalParticle sizeMoisture content

Modeling study of combustion process of oil shale semicoke in a circulating fluidized bed boiler

在线全文

学校读者我要写书评

暂无评论

Carbon Resources Conversion 2018年第3期1卷 273-278页

作者： Yiqun Huang Man Zhang Junfu Lyu hairui yang Key Laboratory for Thermal Science and Power Engineering of Ministry of Education State Key Laboratory of Power SystemsDepartment of Energy and Power EngineeringTsinghua UniversityBeijing 100084China

In this paper,the combustion process of oil shale semicoke was investigated by modeling,where intraparticle mass transfer resistance was especially *** ash formation and attrition characteristics of oil shale semicoke were also investigated by a laboratory test *** burnout time and residence time of different particle sizes were predicted,and the maximum particle size of which oil shale semicoke could be burned out in a 3 MW circulating fluidized bed boiler was obtained.

关键词： Oil shale semicoke Combustion CFB Ash formation Attrition

Restart-up Performance of a CFB Boiler after a Sudden Power Failure Accident

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Thermal Science 2022年第3期31卷 830-839页

作者： YAO Yuge JIANG Ling XIAO Huiren DENG Boyu ZHANG Man ZHANG yang yang hairui LYU Junfu Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Energy and Power EngineeringTsinghua UniversityBeijing100084China

Due to the massive bed materials in its typical main loop,a circulating fluidized bed(CFB)boiler may face greater trouble in operation and restart-up if an unplanned sudden power failure happens in the power *** study aims to explore the restart-up performance of a 170 t/h natural circulation CFB boiler after a sudden power failure and evaluate whether the hot restart-up can be *** heat transfer process after the restoration of the primary air is *** the isothermal property of the bed after the restoration of the power and air supply,the correlation among the accident duration time,bed temperature after the power restores,inlet air temperature,air supply time,and air velocity is *** predicted results indicate that the major influencing factor of the bed temperature during this process is primary air *** provide guidelines for judgment on whether the hot restart-up can be realized,the maximum values of the air supply time and accident duration time for hot restart-up for different types of coals are *** results show both of them have a rapid decrease as the coal ignition temperature in a CFB boiler increases from 450°C to 650°C,which also means that the coal ignition temperature plays a very important role in the restart-up *** on the simulation results of bed temperature during the accident,it is also estimated that the drum level drops by 77.7 mm after 8 hours but still stays in the permissible range.

关键词： CFB boiler sudden power failure restart-up drum level bed temperature

Bubble dynamics properties of B-particles in a quasi-2D gas-solid fluidized bed:Computational particle fluid dynamics numerical simulation and post-processed by digital image analysis technique

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第3期86卷 223-238页

作者： Zemin Yuan Zhong Huang Guotao Qin Guanjia Zhao Suxia Ma hairui yang Guangxi Yue Key Laboratory of Clean and Efficient Combustion and Utilization in the Circulating Fluidized Bed Taiyuan University ofTechnologyTaiyuan030024China Department of Energy and Power Engineering Tsinghua UniversityBeijing100084.China

Bubble dynamics properties play a crucial and significant role in the design and optimization of gas-solid fluidized *** this study,the bubble dynamics properties of four B-particles were investigated in a quasi-two-dimensional(quasi-2D)fluidized bed,including bubble equivalent diameter,bubble size distribution,average bubble density,bubble aspect ratio,bubble hold-up,bed expansion ratio,bubble radial position,and bubble *** studies were performed by computational particle fluid dynamics(CPFD)numerical simulation and post-processed with digital image analysis(DIA)technique,at superficial gas velocities ranging from 2u_(mf) to 7u_(mf).The simulated results shown that the CPFD simulation combining with DIA technique post-processing could be used as a reliable method for simulating bubble dynamics properties in quasi-2D gas-solid fluidized ***,it seemed not desirable for the simulation of bubble motion near the air distributor at higher superficial gas velocity from the simulated average bubble density *** superficial gas velocity significantly affected the bubble equivalent diameter and evolution,while it had little influence on bubble size distribution and bubble aspect ratio distribution for the same *** time-averaged bubble hold-up and bed expansion ratio increased with the increase of superficial gas *** core-annular flow structures could be found in the fluidized bed for all *** average bubble rising velocity increased with the increasing bubble equivalent *** bubble lateral movement,the smaller bubbles might be more susceptible,and superficial gas velocity had a little influence on the absolute lateral velocity of *** simulated results presented a valuable and novel approach for studying bubble dynamics *** comprehensive understanding of bubble dynamics behaviors in quasi-2D gas-solid fluidized beds would provide support in the design,operation,and optimization of gas-solid

关键词： Bubble dynamics properties CPFD simulation Quasi-2D gas-solid fluidized bed Digital image analysis

A state-of-the-art review on transition between the fast fluidization and pneumatic transport of Geldart group B particles

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2023年第2期73卷 78-94页

作者： Boyu Deng Yi Zhang Man Zhang Yi Ding Tuo Zhou Xinhua yang Zhong Huang hairui yang Guangxi Yue State Key Laboratory of Power Systems Department of Energy and Power EngineeringTsinghua UniversityBeijing100084China China Electric Power Planning&Engineering Institute Beijing100120China SDIC Power Holding Co. LtdBeijing100034China

The fluidization state in the circulating fluidized bed(CFB)boiler is crucial to its stable and safe ***,up to now,the research field has not reached unanimity on whether the fluidization regime that the upper furnace of the boiler operates in is the fast fluidization or pneumatic *** this end,this paper reviewed relevant research on the transition between the fast fluidization and pneumatic transport of Geldart group B particles,including the flow characteristics of the fast fluidization,the transition condition between the fast fluidization and pneumatic transport,the determination methods of the transport velocity utr and saturation carrying capacity G_(s)* and the influencing factors on these two *** research findings can provide certain guidelines for the design and optimization of the CFB boiler,and result in plenty of prediction correlations for utr and G_(s)*.Nonetheless,owing to insufficient data available on Geldart group B particles,especially the ones obtained under high temperature or pressure conditions and in large-scale CFB apparatuses,the existing correlations are not well suited for the prediction of u_(tr) and G_(s)* of Geldart group B ***,further efforts are urgently demanded on the fast fluidization transition of Geldart group B particles.

关键词： Fast fluidization transition Transport velocity Saturation carrying capacity Geldart group B particles Circulating fluidized bed

Thermal Inertia of 330 MW Circulating Fluidized Bed Boiler during Load Change

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Thermal Science 2023年第5期32卷 1771-1783页

作者： SUN Guorui WU Haowen LIU Shangzhong LIU Tonghua LIU Jixiang yang hairui ZHANG Man Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Wuhan Yongping Science and Technology Co.Ltd. Wuhan 430000China

The operating principles of Circulating Fluidized Bed(CFB)boilers involve a significant amount of heat accumulation,which forms the thermal inertia of the boiler and hinders the improvement of its variable load response *** study aims to characterize the thermal inertia of CFB boilers by evaluating the change in the boiler's heat accumulation corresponding to the change in unit power *** thermal inertia of a 330MW CFB boiler was determined through the collection of operating data under four different operating conditions of 30%,50%,75%,and 100%*** study proposes to substitute the existing refractory material with a metal grille to reduce the thermal inertia of the *** effect of the metal grille on heat transfer was confirmed through verification on a 440 t/h CFB boiler,and its performance change and thermal inertia reduction were further *** results indicate that over 50%of the total thermal inertia of CFB boilers originates from the refractory *** use of metal grille in place of refractory material improved heat transfer in the furnace,resulting in a decrease of the furnace chamber temperature by 13℃in the 330 MW CFB *** reduction of thermal inertia by 30%-35%will facilitate faster load lifting and lowering of the boiler,fulfilling the requirement for flexible peaking.

关键词： CFB boiler refractory thermal inertia heat accumulation