Entrainment characteristics of fine particles in fluidized bed under preheating conditions

Yin, Shenghua; Tang, Wangyang; Zheng, Xinglong; Tong, Lige; Wang, Li; Liu, Chuanping

doi:10.1016/j.powtec.2016.05.045

Cited by 5 publications

(4 citation statements)

References 15 publications

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“…However, the proposed method has several difficulties. The fluidization of ultrafine silicon particles with high concentration remains a challenge, although some improvements have been reported through external forces and coarse particles. − The reaction and crystallization kinetics of silicon particles is also challenging. Several studies have been conducted on accelerating the crystallization of amorphous silicon nitride by silicon. − However, the nitridation and crystallization of fine silicon particles have not been given in detail.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si₃N₄ at Atmospheric Pressure and 1410 °C

Zheng

Sergeev

et al. 2022

Ind. Eng. Chem. Res.

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The formation of α/β-Si3N4 relates to the reaction process in the direct nitridation method, which can produce cheap ultrafine Si3N4 powder on a large scale in a fluidized bed. Complete nitridation of silicon powder was conducted in a 1 atm nitrogen atmosphere at 1410 °C, which is slightly lower than the silicon melting point of 1414 °C. Comprehensive analyses with thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy show several-stage nitridation kinetics of silicon powder. Compared with previous research projects, more reaction details can be observed. The reaction undergoes evaporation and multiple melting–freezing processes, causing the deviation of the actual reaction curve from the theoretical logarithm curve in a solid–gas reaction. According to heat flow curves and their derivative to time curves, the reaction can be divided into 4 main stages. The repeated melting–freezing phenomenon and the produced α/β-Si3N4 phase were investigated. The increase of particle size increases the liquid–gas and liquid–solid–gas reaction time which causes β-Si3N4 to increase rapidly.

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Section: Introductionmentioning

confidence: 99%

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si₃N₄ at Atmospheric Pressure and 1410 °C

Zheng

Sergeev

et al. 2022

Ind. Eng. Chem. Res.

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“…35−37 Mechanical vibration was also used to change the elutriation of fines from fluidized beds. 38 To understand the process of dust release, it is necessary to elucidate its fundamental physics. With cohesive powders, agglomerate formation should be properly accounted for to describe the fundamental physics.…”

Section: Introductionmentioning

confidence: 99%

“…Sound was also used to promote the filtration effectiveness of vibrated beds , and to promote mixing in fluidized beds. , Furthermore, mechanical vibration shows the capability to break aggregates and other formed structures in fluidized bed which hinder the proper fluidization of group C cohesive powders. − The generally recognized mechanism involves the breakage of clumps and aggregates into fragments small enough to be fluidized. Generally this process is able to turn the fluidization behavior of a Group C powder into that of a Group A powder, characterized by the presence of a fluidization velocity range of homogeneous fluidization. − Mechanical vibration was also used to change the elutriation of fines from fluidized beds …”

Section: Introductionmentioning

confidence: 99%

Dust Release from Aggregative Cohesive Powders Subjected to Vibration

Salehi

Lotrecchiano

Poletto

2017

Ind. Eng. Chem. Res.

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Dust is released from a mechanically vibrated bed of cohesive powders aerated close to the minimum for fluidization. The materials tested were silica and potato starch. The effect of both vibration intensity and vibration frequency on dust formation are verified, and a model to account for these two variables has been developed. A dimensionless dust release parameter has been defined and calculated from the experimental results. This parameter is able to explain the role of the acceleration due to vibration and of cohesive interparticle forces, also accounting for the magnification effects of acceleration intensity close to resonance conditions. However, the same parameter is unable to fully account for changes in dust emission induced by fluidized bed bubbling promoted by vibration frequencies close to resonance. Without considering these effects, frequency determines a reduction of dust release that should be explained by introducing some effects other than those considered in our model

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“…Shin et al [13] investigated the entrainment characteristics of fine powder from solid mixtures (Geldart groups A and C) in gas-solid fluidized beds with or without a tube. Yin et al [14] studied the effects of the superficial velocity of nitrogen gas at room temperature, initial loading quantity of fine particles, vibration intensity, and stirring speed on the entrainment characteristics of fine silicon particles in fluidized bed with vibration, stirring, and coarse particles. 6LOLFRQ SDUWLFOHV PHDQ VL]H RI ȝP DUH XVHG DV entrained materials, and the entrainment characteristics of fine particles are investigated in a cylindrical fluidized-bed (inner diameter of 28 mm and height of 1000 mm) under high speed airflow.…”

Section: Introductionmentioning

confidence: 99%

Entrainment characteristics of fine particles under high speed airflow

et al. 2017

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Abstract. Fine silicon particles (mean size oI ȝP DUH XVHG DV HQWUDLQHG PDWHULDOV DQG WKH HQWUDLQPHQW characteristics of fine particles are investigated in a cylindrical fluidized-bed (inner diameter of 28 mm and height of 1000 mm) under high speed airflow. The effects of the volume flow of gas (Q, 1 m 3 /h to 2.5 m 3 /h), the number of holes (N, 1 to 4), the size of holes (D, 1 mm to 3 mm), and the distance between holes and the upper surface of the material layer (H, -100 mm to 200 mm) on the entrainment characteristics (entrainment rate W and entrained powder-gas ratio R) are experimentally studied through orthogonal experiment. The experimental results show that an increase in Q and H constantly improves the entrainment characteristics; a decrease in D enhances such characteristics, whereas the number of holes N has no significant effect on the entrainment characteristics. An optimal operating condition can result in optimal entrainment characteristics (W, 3.1 g/min and R, 0.058 g/g), which can be achieved with a Q of 2.5 m 3 /h, N of 1, D of 2 mm and H of 200 mm.

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Entrainment characteristics of fine particles in fluidized bed under preheating conditions

Cited by 5 publications

References 15 publications

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si₃N₄ at Atmospheric Pressure and 1410 °C

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si₃N₄ at Atmospheric Pressure and 1410 °C

Dust Release from Aggregative Cohesive Powders Subjected to Vibration

Entrainment characteristics of fine particles under high speed airflow

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Entrainment characteristics of fine particles in fluidized bed under preheating conditions

Cited by 5 publications

References 15 publications

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si3N4 at Atmospheric Pressure and 1410 °C

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si3N4 at Atmospheric Pressure and 1410 °C

Dust Release from Aggregative Cohesive Powders Subjected to Vibration

Entrainment characteristics of fine particles under high speed airflow

Contact Info

Product

Resources

About

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si₃N₄ at Atmospheric Pressure and 1410 °C

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si₃N₄ at Atmospheric Pressure and 1410 °C