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Phase-Plane Invariant Analysis of Pressure Fluctuations in fluidized beds

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Tsinghua Science and Technology 2007年第3期12卷 284-289页

作者：王晓亮何榕 Toshiyuki Suda Junichi Sato Department of Thermal Engineering Tsinghua University Technical Development Department Ishikawajima-Harima Heavy Industries Co.Ltd. Yokohama 235-8501Japan

Partial agglomeration is a major problem in fluidized beds. A chaotic analytical method based on the phase-plane invariant of the pressure fluctuations in the fluidized beds has been used to warn of agglomeration at an early stage. Cold tests （no combustion） and hot tests （combustion） in fluidized beds show that the phase-plane invariant of the pressure fluctuations can distinguish the dynamic behavior of fluidized beds with different flow rates in cold tests. With combustion, when the flow rate was kept constant, agglomeration was detected very early by looking at the phase-plane invariant. The phase-plane invariant can be used to distinguish changes in fluidized beds due to changes in the flow rate, agglomeration, or various other factors. Therefore, this reliable agglomeration early warning system can be used for better control of circulating fluidized beds.

关键词： pressure fluctuation chaos phase-plane invariant fluidized beds

EXPERIMENTAL RESEARCH OF CYLINDER TO BED HEAT TRANSFER IN AGITATED fluidized beds

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Journal of Hydrodynamics 2000年第4期12卷 36-40页

作者： Ma, J.H. Dep. of Air-condition Eng. Shandong Inst. of Archit. and Eng. Jinan 250014 China

Cylinder-to-bed heat transfer in agitated fluidized beds was studied experimentally. In the experiments, the aluminum particles were used as bed material, the diameter of those ranged from 0.5 mm to 2 mm. The effects of gas velocity, particles size, and agitator rotary speed on heat transfer were studied. From the experimental results, we have come to the following conclusion: (1) there are optimal ranges for airflow velocity and rotary speed to get optimal heat transfer coefficient; (2) the cylinder-to-bed heat transfer is greatly affected by gas velocity, rotary speed and particles sizes, and the effect of rotary speed on heat transfer is similar to that of gas velocity; (3) higher heat transfer coefficient is obtained with smaller particles.

关键词： fluidized beds Heat transfer Mass transfer Two phase flow

fluidized roasting reduction kinetics of low-grade pyrolusite coupling with pretreatment of stone coal

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International Journal of Minerals,Metallurgy and Materials 2013年第3期20卷 221-227页

作者： Ya-li Feng Zhen-lei Cai Hao-ran Li Zhu-wei Du Xin-wei Liu School of Civil and Environmental Engineering University of Science and Technology Beijing State Key Laboratory of Biochemical Engineering Institute of Process Engineering Chinese Academy of Sciences

Based on the fluidized roasting reduction technology of low-grade pyrolusite coupling with pretreatment of stone coal, the manganese reduction efficiency was investigated and technical conditions were optimized. It is found that the optimum manganese reduction efficiency can be up to 98.97% under the conditions that the mass ratio of stone coal to pyrolusite is 3：1, the roasting temperature of stone coal is 1000℃, the roasting temperature of pyrolusite is 800℃, and the roasting time is 2 h. Other low-grade pyrolusite ores in China from Guangxi, Hunan, and Guizhou Provinces were tested and all these minerals responded well, giving -99% manganese reduction efficiency. Meanwhile, the reduction kinetic model has been established. It is confirmed that the reduction process is controlled by the interface chemical reaction. The apparent activation energy is 36.397 kJ/mol.

关键词： pyrolusite ore roasting ore reduction fluidized beds kinetics stone coal

Modeling study on devolatilization of coal particle in fluidized bed under pressurized oxy-fuel combustion

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Meitan Xuebao/Journal of the China Coal Society 2022年第11期47卷

作者： Li, Lin Duan, Lunbo Wu, Wanqiang Sun, Guang Key Laboratory of Energy Thermal Conversion and Control Ministry of Education Southeast University Nanjing 210096 China

Pressurized oxy-fuel combustion is considered one of the most promising CO2 capture technologies, which has gradually attracted the attention of academia and industry in recent years. However, due to the difficulty of the pressurization experiment, the combustion process is like a "black box", and the acquisition of combustion information is not rich, the combustion mechanism of coal under pressurized oxy-fuel conditions is not sufficient. In this work, the influence mechanism of O2/CO2 and O2/N2 atmospheres on the devolatilization process of a single coal particle was studied by establishing the devolatilization model. The model considered the heat transfer and the temperature gradient inside the coal particle. The model used the unsteady one-dimensional particle model to describe the drying and devolatilization processes of the single coal particle. The results showed that the model has good applicability, and the error between the calculated and experimental results was less than 20%. The sensitivity analysis of the model showed that the specific heat capacity of bed material and fuel, fuel size, fuel density, fuel moisture content and total heat transfer coefficient between bed material and fuel have a great influence on the drying time. The specific heat capacity of bed material, transfer coefficient, fuel density and size greatly influence the devolatilization time. The specific heat capacity of bed material, heat transfer coefficient, fuel density and fuel size are the main factors affecting the peak value of temperature gradient inside and outside the particle. With the increase of pressure and bed temperature, the heat transfer between coal particle and bed material increased, which also brought lower drying time and devolatilization time and increased the peak temperature difference between inside and outside the particles. Compared with N2 atmosphere, the drying time and devolatilization time decreased slightly under CO2 atmosphere, and the temperature difference between inside and outside particles in

关键词： fluidized beds

Mathematical Simulation on Oxidation of Ilmenite in fluidized Bed

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Rare Metals 1996年第1期15卷 51-58页

作者：孙康东北大学有色金属系辽宁沈阳

An unsteady-state mathematical model describing the behaviors of gas and solid during the oxidation of ilmenite in a fluidized bed was developed on the basis of the two-phase theory of a fluidized-bed reactor. The longitudinal distribution of the concentration of gaseous species and that of the unreacted ratio of solid material in both bubble phase and emulsion phase as well as their variation with reaction time were determined by means of mathematical simulation with kinetic parameters measured experimentally, furthermore, the reaction behavior of particles with different size in a multiparticle system was also analyzed, and finally, the potential way for increasing the reactor efficiency was put forward.

关键词： Fluidization fluidized beds Mathematical models Oxidation Reaction kinetics

Oxidation Kinetics of Ilmenite Powder in fluidized Bed

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Rare Metals 1995年第1期14卷 26-32页

作者：孙康刘寅虎崔雅茹东北大学有色金属冶金系辽宁沈阳

The oxidation kinetics of Panzhihua ilmenite was studied in a fluidized bed in the temperature range of 1053-1153 K. Within this temperature interval, the reaction can be expressed: From the experimental results, it w... 详细信息

关键词： fluidized beds Oxidation Powders Reaction kinetics

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Preface

Particuology 2010年第1期8卷 1-1页

作者： Chao Zhu New Jersey Institute of Technology,USA Liang-Shih Fan The Ohio State University,USA New Jersey Institute of Technology USA The Ohio State University USA

This special issue of PARTICUOLOGY is focused on the advanced topics of multiphase flow dynamics and chemical kinetics in particulate systems. The papers included represent not only the fundamental aspects of the basic parametric effects and mechanisms of such systems but also their applied nature involving such transport and reactive units as fluidized beds. risers, and downers.

关键词： chemical kinetics multiphase flow fluidized beds special aspects topics nature