Numerical simulation of particle motion and heat transfer in a rotary kiln

Liu, Hong; Yin, Huiming; Zhang, Ming; Xie, Maozhao; Xi, Xi

doi:10.1016/j.powtec.2015.10.007

Cited by 38 publications

(25 citation statements)

References 33 publications

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“…The downward velocity in the upper layer is obviously larger than in the lower layer, improving the performances of mixing and heat transfer between gas and particle phases. This thin layer is called the active layer [6]. The particles in the lower layer are stacked and move upward with the kiln by the friction.…”

Section: Resultsmentioning

confidence: 99%

“…The particles in the lower layer are stacked and move upward with the kiln by the friction. The small relative velocity in this thick layer leads to the weak particles mixing and heat transfer, which is called the passive layer [6]. As displayed in left and middle drawings of partial enlargement, the particle velocity vector at the bed surface is at an angle rather than being parallel to the surface.…”

Section: Resultsmentioning

confidence: 99%

“…Rotary kilns are widely applied in modern industry, such as cement, metallurgy, chemicals, and energy field due to their good mixing performance, high heat transfer efficiency, and large handling capacity [6,7]. In addition, the relatively low particle motion velocity in rotary kilns results in the small collision force between particles and between particle and wall.…”

Section: Mathematical Problems In Engineeringmentioning

confidence: 99%

“…In the past decades, modeling and numerical simulation have been used to provide a detailed insight and quantitative guidelines for reactor design and optimization. However, existing work for rotary kilns focuses on the flow field [7][8][9], mixing/segregation [10][11][12][13], and heat transfer performance [6,14,15]; simulation of chemical processes in a rotary kiln is still in its infancy due to the complexity of coupling of dense gas-solid flow, heat transfer, and reactions [16]. There are only few modeling researches concerning the reacting flow for rotary kilns, which can be categorized two types.…”

Section: Mathematical Problems In Engineeringmentioning

confidence: 99%

See 3 more Smart Citations

Modeling of Oxidation Process of Coal Tar Pitch in Rotating Kilns

Xie

Wang

Shao

et al. 2019

Mathematical Problems in Engineering

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In this paper, a three-dimensional numerical model has been developed to study the process of oxidative weight increment of coal tar pitch in a rotating kiln. Based on the two-fluid method, the gas phase is modeled by realizable k-turbulent model and the solid phase is modeled by kinetic theory of granular flow. The dense gas-solid flow, heat transfer, and oxidation reaction for the bed and freeboard regions are simultaneously solved. The model is applied to a rotating kiln with a cylinder of 0.75 m length and 0.4 m diameter in the front and circular truncated cone on exit side. The detailed verification of model is firstly performed by comparisons with the available experimental data. The particle velocity profiles, product gas compositions, and various forms of solid motion in rotary kilns are contrastively analyzed. Afterwards, simulations are carried out to obtain the primary hydrodynamic and reactive characteristics in the rotary kiln. At the steady state, the particle velocity peak is located at the active layer surface, while the velocity has the opposite direction in the passive layer. The bed region generally has a higher temperature than the freeboard due to the large thermal capacity. The concentrations of product gas compositions, such as CO 2 , CO, and CH 4 , and solid product of oxidation, increase sharply near the surface and then keep on the steady values inside the bed. The effects of rotational speed of the rotary kiln and flow rate of air are also studied. The increasing rotational speed significantly accelerates the particle movement of the active layer and raises the final oxidative yield of coal pitch spheres. By contrast, increasing the flow rate of air has little effect on the particle motion and oxidation yield of coal pitch.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Mathematical Problems In Engineeringmentioning

confidence: 99%

Section: Mathematical Problems In Engineeringmentioning

confidence: 99%

See 2 more Smart Citations

Modeling of Oxidation Process of Coal Tar Pitch in Rotating Kilns

Xie

Wang

Shao

et al. 2019

Mathematical Problems in Engineering

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“…It is extensively used metallurgical engineering, chemical engineering, pharmaceutical engineering, and other fields due to its simplicity . Under actual working conditions, granule motion and mixing are achieved by drum rotation. Furthermore, many applications also involve heat transfer, whereby particles come into contact with the heated inner wall of the drum , .…”

Section: Introductionmentioning

confidence: 99%

Mixing and Heat Transfer of Granular Materials in an Externally Heated Rotary Kiln

et al. 2019

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A heat transfer model based on the discrete element software EDEM and the secondary development tool C++ is developed to simulate the mixing and heat transfer process of particles under different parameters. This model is validated by comparison with experimental data and proved reasonable. It aims to study the heat transfer law of flowing particles in an externally heated rotary kiln and reveal the correlation between mixing and heat transfer from the mechanism. The results show that the combination of the total contact area between adherent particles and the drum wall, the mean temperature difference between adherent particles and the drum wall, the total contact area between particles, and the mean temperature difference between particles affect the heat transfer process. Changes in the temperature differences caused by the mixing rate dominate the heat transfer at different speeds or filling rates.

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Experimental research and numerical analysis on thermal dynamic characteristics of rotary kiln

Wang

Cheng

2019

Can J Chem Eng

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The rotary kiln is a piece of equipment that consumes an extensive amount of energy. The thermal dynamic characteristics of the rotary kiln include conduction, convection, radiation, and combustion characteristics, which are closely bound up with the energy consumption of the kiln. In this paper, both experimental and numerical studies are performed to understand the relationship between the thermal dynamic characteristics of the rotary kiln and the factors that affect them. In the experimental section, the shell temperature and coating thickness of the kiln cylinder were measured, which shows the thermal dynamic characteristics of the rotary kiln. In the numerical section, a three-dimensional numerical model with ANSYS software is set up to research the fluid flow, combustion, and heat transfer characteristics of the rotary kiln under different working conditions. The numerical simulation results presented reasonable agreement with the experimental data. The results indicate that coating thickness affects the heat transfer conduction of the kiln and the burner structure affects the combustion and convection heat transfer in a kiln. Fugitive constituents of coal, pulverized coal concentration, excess air ratio, and oxygen content can influence the characteristics of the combustion and heat transfer processes.

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Numerical simulation of particle motion and heat transfer in a rotary kiln

Cited by 38 publications

References 33 publications

Modeling of Oxidation Process of Coal Tar Pitch in Rotating Kilns

Modeling of Oxidation Process of Coal Tar Pitch in Rotating Kilns

Mixing and Heat Transfer of Granular Materials in an Externally Heated Rotary Kiln

Experimental research and numerical analysis on thermal dynamic characteristics of rotary kiln

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