Research Article D. K. Chibwe*, G. Akdogan, and P. Taskinen Numerical Investigation of Combined Top and Lateral Blowing in a Peirce-Smith Converter Abstract: Typical current operation of lateral-blown Peirce-Smith converters (PSCs) has the common phenom- enon of splashing and slopping due to air injection. The splashing and wave motion in these converters cause metal losses and potential production lost time due to intermittent cleaning of the converter mouth and thus reduced process throughput. Understanding of the effect of combined top and lateral blowing could possibly lead to alternative technology advancement for increased pro- cess efficiency. In this study, computational fluid dynamics (CFD) simulations of conventional common practice (lateral blowing) and combined (top and lateral blowing) in a PSC were carried out, and results of flow variables (bath velocity, turbulence kinetic energy, etc.) were compared. The two-dimensional (2-D) and three- dimensional (3-D) simulations of the three-phase system (air–matte–slag) were executed utilizing a commercial CFD numerical software code, ANSYS FLUENT 14.0. These simulations were performed employing the volume of fluid and realizable k À ε turbulence models to account for multiphase and turbulent nature of the flow, respec- tively. Upon completion of the simulations, the results of the models were analysed and compared by means of density contour plots, velocity vector plots, turbulent kinetic energy vector plots, average turbulent kinetic energy, turbulent intensity contour plots and average matte bulk velocity. It was found that both blowing con- figuration and slag layer thickness have significant effects on mixing propagation, wave formation and splashing in the PSC as the results showed wave formation and splashing significantly being reduced by employing combined top- and lateral-blowing configurations. Keywords: computational fluid dynamics, simulations, Peirce-Smith converter, combined blowing *Corresponding author: D. K. Chibwe, Department of Process Engineering, University of Stellenbosch, P Bag X1, Matieland, Stellenbosch 7602, South Africa, E-mail: deside@sun.ac.za G. Akdogan, Department of Process Engineering, University of Stellenbosch, P Bag X1, Matieland, Stellenbosch 7602, South Africa, E-mail: gakdogan@sun.ac.za P. Taskinen, Department of Material science and Engineering, School of Chemical Technology, Aalto University, P.O Box 16200, FI-00076 Aalto, Finland, E-mail: pekka.taskinen@aalto.fi 1 Introduction Pyrometallurgical gas injection systems are being used in various metal producing processes. In such operations, an increase in process efficiency can lead to higher pro- duct quality and quantity, as well as a decrease in pro- cess costs. Considerable attention has been given to the improvement of these systems. One such a submerged injection process is the conversion operation in the cop- per and platinum group metals smelting industries. The most widespread used industrial equipment to perform conversion (chemical oxidation of iron and sulphur) is the Peirce-Smith converter (PSC), which has been utilized since 1905 when it was first conceived at Baltimore Copper Company and currently accounts for more than 90% of the world production of copper [1]. Although the majority of research on mixing and injection phenomena in gas–liquid multiphase systems have been conducted on steel making and ladle metal- lurgy [2–4], various studies regarding fluid flow phenom- ena in PSCs have also been conducted [5–7]. The air injected into the PSC provides energy which is delivered in three forms namely kinetic, buoyancy and expansion. These affect the physical and chemical processes taking place in the converter such as oxygen efficiency, mixing, heat and mass transfer, slopping, splashing, converting rate, dispersion and accretion growth [8, 9]. The converting process can be classified as semi- continuous and auto-thermal. Quality and quantity of mixing are extremely important, since there are chemical reactions taking place with products being formed. According to literature [3, 10], mixing will promote doi 10.1515/cppm-2013-0036 Chemical Product and Process Modeling 2013; aop Brought to you by | University of Stellenbosch Authenticated | deside@sun.ac.za author's copy Download Date | 11/5/13 5:38 PM