Vivek V. Buwa
Applications

Gas induced mixing in a Basic Oxygen Furnace (BOF)

 
In Basic Oxygen Furnace (BOF) steel making process, inert gas is injected through bottom tuyeres to provide sufficient stirring in metal bath that in turn improve the efficiency of steel refining process, hence steel quality. Gas-liquid flow in BOF is inherently unsteady and complex interactions among the meandering plumes influence the local mixing inside the vessel. Therefore, understanding and abilities to manipulate the underlying dynamics of flow is crucial to improve the mixing efficiency of the process. In this work, cold flow experiments were performed in a scaled-down model of BOF vessel to measure the local gas volume fraction distribution and mixing time using in-house developed voidage probes and miniaturized conductivity probes, respectively. Instantaneous gas volume fraction fluctuations were used to characterize the vessel-scale re-circulatory flow that governs the mixing inside the vessel. 3D/transient Euler-Lagrange (EL) without/with Volume of Fluid (VOF) simulations were performed to establish the role of free gas-liquid interface on the dynamics of gas-liquid flow and mixing in BOF vessel. The results showed that for lower height to diameter (H/D) ratios (≤ 0.5), effect of free surface needs to be considered for accurate predictions of gas-liquid flow and mixing time. The experimentally verified computational model was used to analyze the contributions of different mixing mechanisms and the role of primary and secondary flow in determining the dynamics of gas-liquid flow and eventually the mixing time. Such an understanding and knowledge will be help to improve the mixing performance of the BOF vessel used in steel industry.
Scaled-down cold flow model of BOF vessel Instantaneous bubble positions, streamlines (colored by liquid velocity magnitude) and instantaneous tracer mass fraction distribution predicted using EL+VOF (top) and EL (bottom) approaches (Quiyoom et. al. 2017, AIChE Journal)

Publications/conference presentations:

·      Quiyoom, A., Ajmani, S. K. and Buwa, V. V. (2017). Role of Free Surface on GasInduced Liquid Mixing in a Shallow Vessel. AIChE Journal, in press, doi: 10.1002/aic.15697.

·       Quiyoom, A., Golani, R., Singh, V. and Buwa, V. V. (2017). Effect of Differential Flow Schemes on Gas-Liquid Flow and Liquid Phase Mixing in Basic Oxygen Furnace (BOF). Chemical Engineering Science, in press, doi: 10.1016/j.ces.2017.03.010.

·        Quiyoom, A., Buwa, V. V. and Ajmani, S. K. (2017). Euler‒Lagrange Simulations of Gas‒Liquid Flow in a Basic Oxygen Furnace and Experimental Verification. In Fluid Mechanics and Fluid Power–Contemporary Research, Springer India, 1151‒1161.

·      Quiyoom, A., Buwa, V. V. and Ajmani, S. K. (2017). Optimization of the Bottom Tuyere Configuration in a Basic Oxygen Furnace through CFD Simulations and Experiments. (Submitted in Chemical Engineering Journal).

·       Abdul Quiyoom, Ravi Golani, Vikas Singh and Vivek V. Buwa, 2017, "Effect of Differential Flow Schemes on Gas-Liquid Flow and Liquid Phase Mixing in a Basic Oxygen Furnace (BOF)", Accepted for presentation at 13th International Conference on Gas-Liquid and Gas-Liquid-Solid Reaction Engineering (GLS 13) to be held at Brussels (Belgium), 20-23 August 2017.

·       Quiyoom, A.; Buwa, V. V. and Ajmani, S. K., 2015, “Role of Free Surface in Liquid Mixing in Shallow Gas-Liquid Process Vessels”, presented at 12th International Conference on Gas-Liquid and Gas-Liquid-Solid Reactor Engineering (GLS-12), New York (USA), 28 June – 01 July 2015.

·     Quiyoom, A.; Buwa, V. V. and Ajmani, S. K., " Euler-Lagrange Simulations of Gas-Liquid Flow in a Basic Oxygen Furnace and Experimental Verification”, presented at 5th International and 41st National Conference on Fluid Mechanics and Fluid Power, Kanpur (India), 12-14 December 2014.