Wall-to-solid heat transfer coefficient in flighted rotary kilns: Experimental determination and modeling

Njeng, Alex Stéphane Bongo; Vitu, Stéphane; Clausse, Marc; Dirion, Jean-Louis; Debacq, Marie

doi:10.1016/j.expthermflusci.2017.10.024

Cited by 28 publications

(3 citation statements)

References 41 publications

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“…At the same time, less work has been done to characterize heat transfer in bladed mixers with heating jackets. In the past, studies on DEM modeling for heat transfer in particulate systems have focused on other flows and geometries, such as static packed beds, 14 shear flows, 15,16 chute flows, 17 pneumatic conveyors, 18 rotating drums, [19][20][21] and fluidized beds. 22 Currently, few publications exist on DEM modeling for agitated heated mixers.…”

Section: Introductionmentioning

confidence: 99%

Infrared temperature measurements and DEM simulations of heat transfer in a bladed mixer

et al. 2022

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An understanding of heat transfer in a bladed mixer is important for drying of pharmaceutical drug crystals. This study presents thermal imaging experiments of the particle bed surface in a bladed mixer to investigate how the impeller speed influences the rate and the uniformity of heat transfer. Next, the process is simulated using the discrete element method. The bed thermal properties are lumped into an effective thermal conductivity, that is calibrated for one impeller speed. The experiments and the simulations show the same trends and generally agree well for all agitated beds. However, to obtain good agreement of the rate of heat transfer between the simulations and experiments in a static bed, we need to adopt a higher thermal conductivity than for the agitated beds. Finally, we discuss the implications of these results for the design of operating protocols.

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Section: Introductionmentioning

confidence: 99%

Infrared temperature measurements and DEM simulations of heat transfer in a bladed mixer

et al. 2022

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“…The processes taking place in them are characterized by different parameters, however, it is worth quoting some theses of these works, as they are also justified in the case of rotary kilns in incinerators. The author [7] emphasizes that alkaline corrosion takes place at higher temperatures, leading to the degradation of the lining. The research carried out by [8] presents the view concerning the dependence of the operating conditions of the furnace on the thickness of the agglomerated material in the furnace.…”

Section: Introductionmentioning

confidence: 99%

Optimization and Security of Hazardous Waste Incineration Plants with the Use of a Heuristic Algorithm

Wajda

Jaworski

2021

Sensors

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The amount of generated waste, which increases every year, is a serious problem of the modern world. In particular, attention should be paid to hazardous waste and methods of its disposal. One of the most used in this context is thermal treatment in dedicated incinerators equipped with a rotary kiln. Conducting the process requires, inter alia, supplying the furnace with a batch of batch material with appropriate parameters. Improper operation in this regard may cause negative environmental effects and operational problems. The key here is to select different types of hazardous waste and compose batch portions. The paper presents an application that optimizes the work of waste incineration plant operators. At the same time, this tool can be described as ensuring security at this stage of the process. The application implements an ant colony algorithm that selects the optimal solution to the problem, which has been formulated here as the types and masses of the batch mixture components with given parameters. The application has been tested in the laboratory and real conditions with satisfactory results.

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“…Boateng and Barr [9] developed a quasi-3D model of the thermal transport in a rotary kiln by comprising a 1D axial model together with a 2D model of the rotary kiln cross-section for the bed material. Several researchers have also studied the conductive heat transfer between the wall and bed material [10][11][12][13] as well as the convective heat transfer between the freeboard and the wall and bed materials [14]. The movement of the bed material, the different modes of heat transfer as well as the impact from different parameters on heat transfer in a rotary kiln, such as the temperature dependent radiative emissivity of different materials, has been summarized by Specht [15].…”

Section: Introductionmentioning

confidence: 99%

Discrete-Ordinates Modelling of the Radiative Heat Transfer in a Pilot-Scale Rotary Kiln

et al. 2020

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This paper presents work focused on the development, evaluation and use of a 3D model for investigation of the radiative heat transfer in rotary kilns. The model applies a discrete-ordinates method to solve the radiative transfer equation considering emission, absorption and scattering of radiation by gas species and particles for cylindrical and semi-cylindrical enclosures. Modelling input data on temperature, particle distribution and gas composition in the radial, axial and angular directions are experimentally gathered in a down-scaled version of a rotary kiln. The model is tested in its capability to predict the radiative intensity and heat flux to the inner wall of the furnace and good agreement was found when compared to measurements. Including the conductive heat transfer through the furnace wall, the model also satisfactorily predicts the intermediate wall temperature. The work also includes a first study on the effect of the incident radiative heat flux to the different surfaces while adding a cold bed material. With further development of the model, it can be used to study the heat transfer in full-scale rotary kilns.

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Wall-to-solid heat transfer coefficient in flighted rotary kilns: Experimental determination and modeling

Cited by 28 publications

References 41 publications

Infrared temperature measurements and DEM simulations of heat transfer in a bladed mixer

Infrared temperature measurements and DEM simulations of heat transfer in a bladed mixer

Optimization and Security of Hazardous Waste Incineration Plants with the Use of a Heuristic Algorithm

Discrete-Ordinates Modelling of the Radiative Heat Transfer in a Pilot-Scale Rotary Kiln

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