3D-simulation of the thermal performance of a coke calcining kiln

Bui, R. T.; Simard, Guy; Kocaefe, Yasar S.; Charette, André B.; Lacroix, Marcel; Jain, Sanjay K.; Perron, Jean; Proulx, André L.; Barr, P. V.

doi:10.1016/b978-0-08-041444-7.50035-4

Cited by 5 publications

(1 citation statement)

References 6 publications

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“…has led to bolder modelling efforts for related furnaces. Bui et al (1991Bui et al ( , 1993bBui et al ( , 1995 were the fi rst to construct a three-dimensional model for a rotary petroleum coke calciner. A coupled simulation of the physical phenomena that occur in the kiln was undertaken.…”

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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Section: Rotary Kiln Modellingmentioning

confidence: 99%

Modelling the Rotary Lime Kiln

et al. 2008

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Fours rotatifs: Modèle dynamique du mouvement du lit

Perron¹,

Bui

1994

Can J Chem Eng

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The motions of the granular bed inside a rotary furnace are governed by complex dynamics consisting of two modes. The axial velocity of the active layer on top of the bed represents the fast mode, while the overall velocity in the bed follows a slower mode. The proposed nonlinear model focuses on the dynamics of the slow mode. The difficulties of an analytic solution are avoided by a numerical method that employs several correlations. The model can reproduce the experimental transient responses. It is concluded that rotary furnaces respond better to small amplitude excitations than to large ones; consequently, closed‐loop control is well suited for this type of furnace.

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Building useful and user-friendly computer models of metallurgical processes

Bui

1992

JOM

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3D-simulation of the thermal performance of a coke calcining kiln

Cited by 5 publications

References 6 publications

Modelling the Rotary Lime Kiln

Modelling the Rotary Lime Kiln

Fours rotatifs: Modèle dynamique du mouvement du lit

Building useful and user-friendly computer models of metallurgical processes

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