Three-Dimensional Modeling of Lime Kilns

Georgallis, M.; Nowak, P.; Salcudean, M.; Gartshore, I. S.

doi:10.1115/pvp2002-1603

Cited by 6 publications

(7 citation statements)

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“…The analytical derivation of the realizable k-ɛ turbulence model, its constants, and its additional terms and functions in the transport equations for k and ɛ are different from those in the standard k-ɛ and RNG k-ɛ models. The transport equations for the realizable k-ɛ model are given in Equations (3,4).…”

Section: Numerical Approach and Assumptionsmentioning

confidence: 99%

“…Rotary kilns have a wide range of industrial applications including cement industries, metallurgy, and incinerating waste materials . This is related to the rotary kilns being able to work at a high burning zone temperature, such as lime burning (1200 °C), cement clinker burning (2000 °C), calcination of petroleum coke (1100 °C), and calcination of aluminum oxide (1300 °C) . However, cement industries are considered the essential applications of rotary kilns…”

Section: Introductionmentioning

confidence: 99%

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Study of Parameters Influencing Fluid Flow and Wall Hot Spots in Rotary Kilns using CFD

et al. 2016

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In this paper, 3-D-CFD simulation using an ANSYS-Fluent package in a 4 m diameter kiln with 40 m length firing methane (CH 4 ) gas is applied to avoid undesirable thermal behaviour (wall hot spots; peak wall temperatures) in industrial rotary kilns. New influencing parameters are introduced, including primary air ratio, burner configuration (two configurations with different fuel jet momentums), and burner power. The influence of these parameters on the peak kiln flame and on wall temperatures, flame radiation heat flux, radiative heat transfer coefficient, temperature contours, and pathlines are investigated and discussed. Preliminary comparison of jet flames with available experimental data is carried out to select and validate the proper turbulence model for the present simulations. Results reveal that the peak flame temperature, flame radiation heat flux, and radiative heat transfer coefficient increase with higher fuel jet momentum, lower primary air ratio, and higher burner power. On the other hand, the wall hot spots emerge when operating the kiln at higher burner power or by lowering the jet momentum (larger fuel inlet diameter). Stable flames and a higher recirculation size can be obtained by operating the kiln under a higher primary air ratio and higher jet momentum (narrower fuel inlet diameter). Based on these results, operators are shown a way to adjust controllable kiln parameters to reduce wall hot spots and to improve product quality, in addition to controlling the ringing problems.

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Section: Numerical Approach and Assumptionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study of Parameters Influencing Fluid Flow and Wall Hot Spots in Rotary Kilns using CFD

et al. 2016

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“…The combustion zone, tertiary air use (air is injected into the calcining zone, mid-length, through nozzles fi xed on the rotating wall) and bed chemistry makes the coke calcining kiln considerably different from the rotary lime kiln considered in the current research. Previously reported work on the lime kiln (Georgallis et al, 2002) included coupling of the hot fl ow model with a non-rotating wall. The model was validated using experimental data available from UBC's pilot kiln trials (Alyaser, 1998).…”

Section: Rotary Kiln Modellingmentioning

confidence: 99%

Modelling the Rotary Lime Kiln

et al. 2008

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I n a Kraft process of pulp and paper production, white liquor containing active chemicals sodium hydroxide, NaOH, and sodium sulfi de, Na2S, are recovered in the sodium loop for re-use, as shown in Figure 1. The wood pulp fi bres go through a bleaching process. The pulp then fl ows through the headbox and is dried to make the fi nal product.In the sodium loop, black liquor is concentrated and burned in the recovery boiler. The resulting smelt is dissolved and reacted with quick lime, CaO, to convert sodium carbonate, Na 2 CO 3 , into NaOH.In the calcium loop of the recovery cycle, lime kilns are used to convert lime mud back to quick lime for re-use in the causticizing process. The rotary lime kiln considered in this work is effectively a direct-contact counter-fl ow heat exchanger. The endothermic reaction that takes place in the lime uses energy from the hot burnt gases that fl ow above the mud.The rotary lime kiln is a long cylinder typically 3 m in diameter and 90 m in length. It rotates about its axis at roughly 1 rpm and is sloped at 2°d. Lime mud is fed from the elevated cold end and moves down the kiln due to rotation and gravity. The retention time for the mud in the kiln is two to three hours. The hot end, in which the burner operates, is typically maintained at about 1200°C by burning fuel (natural gas or oil).Modelling the details of the burner is important. Many problems associated with the kiln operation, such as poor product quality, low fuel effi ciency and short refractory life can be related to the design and operation of the burner.Physical phenomena present in the kiln include: threedimensional turbulent gas fl ow with combustion, threedimensional non-Newtonian fl ow in the lime mud (bed motion), A three-dimensional steady-state model to predict the fl ow and heat transfer in a rotary lime kiln is presented. All important phenomena are considered for the pre-heat and calcination zones including turbulent gas fl ow, buoyancy, all modes of heat transfer, evolution and combustion of species and granular bed motion with calcination reaction. The model is based on a global solution of three sub-models for the hot fl ow, the bed and the rotating wall/refractories. Information exchange between the models results in a fully coupled 3-D solution of a rotating lime kiln. The overall model is validated using UBC's pilot kiln trials (5.5 m laboratory kiln). Results for this case are presented and potential implications are discussed.On présente un modèle tridimensionnel en régime permanent pour prédire l'écoulement et le transfert de chaleur dans un four à chaux rotatif. Tous les phénomènes importants sont considérées pour les zones de pré-chauffe et de calcination, y compris l'écoulement de gaz turbulent, la fl ottabilité, tous les modes de transfert de chaleur, l'évolution et la combustion des espèces et le déplacement de lit granulaire avec la réaction de calcination. Le modèle repose sur une solution globale de trois sous-modèles pour l'écoulement chaud, le lit et les parois rotatives/réfractaires. L...

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“…Basically, rotary kilns can be considered as heat exchangers in which heat is liberated from combustion gases through the solid material and produces cement [1]. Rotary kilns are used in several industrial applications comprising lime and cement firing [2], petroleum coke calcination [3], and aluminum oxide calcination [4,5]. Cement production is considered to be dominated by the use of rotary kilns.…”

Section: Introductionmentioning

confidence: 99%

Swirled Jet Flame Simulation and Flow Visualization Inside Rotary Kiln—CFD with PDF Approach

et al. 2020

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CFD (computational fluid dynamics) simulation using a commercial package (Fluent-ANSYS) on industrial rotary kilns using annulus-type burners and methane gas was carried out to examine the characteristics of the flame length and flow visualization. New influencing design and operating parameters—primary air swirl number, primary air inlet annulus diameter, and secondary air temperature—were investigated and discussed. The influence of these parameters on axial temperature distribution, axial mean mixture fractions, velocity vectors, mixture fractions, and temperature contours were investigated. The current numerical findings were compared with existing experimental results to validate the simulation approach. The results showed that the primary air swirl number had a remarkable influence on the flame length at a lower primary air inlet annulus diameter ratio of 2.3. Moreover, the flame length increased by 20% and 6% with increasing the swirl number from zero to one for primary air inlet annulus diameter ratios of 2.3 and 5, respectively, and it also increased by 19% with increasing primary air inlet annulus diameter ratio from 2.3 to 5.

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Three-Dimensional Modeling of Lime Kilns

Cited by 6 publications

References 0 publications

Study of Parameters Influencing Fluid Flow and Wall Hot Spots in Rotary Kilns using CFD

Study of Parameters Influencing Fluid Flow and Wall Hot Spots in Rotary Kilns using CFD

Modelling the Rotary Lime Kiln

Swirled Jet Flame Simulation and Flow Visualization Inside Rotary Kiln—CFD with PDF Approach

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