Geometric structure optimization of impeller for KR desulfurization
JIA Shu-yuan1,2, WANG Rui-zhi3, OUYANG De-gang4, SHANG Shao-wei1,2, WANG Qiang1,2, HE Zhu1,2
1. The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China; 2. Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China; 3. Baosteel Central Research Institute, Shanghai 201900,China; 4. Research and Development Center of Wuhan Iron and Steel Co., Ltd., Baosteel Central Research Institute, Wuhan 430083, Hubei, China
Abstract：The KR (kanbara reactor) method is the preferred process for stable and deep desulfurization in the pretreatment stage of molten iron and is widely used in the modern steelmaking industry. The mixing of the molten iron and the desulfurizer is driven by stirring the blades immersed in the molten iron, which will benefit good dynamic conditions. However, the desulfurizer will coagulate in large quantities before participating in the reaction by the forced vortex zone at the stirring stage, making its utilization rate low. Two easy-to-use impellers (staggered impeller and high-low impeller) were designed, of which purpose is to strengthen the axial flow near the blade by the height difference of adjacent blades, which destroy the flow characteristics in the forced vortex zone and enhance the relative motion between molten iron elements. Thereby, the adverse impact of the forced vortex zone on the KR desulfurization mixing effect was reduced, and the mixing effect of molten iron and desulfurizer was increased. In the meantime,the VOF (volume of fluid) and DPM (discrete phase model) models are used to establish the three-dimensional transient mathematical model of the KR mixing process. The numerical results depict that the influences of the traditional four-blade impeller and two new types of impellers on the hot metal flow, particle dispersion, dead zone range, and the proportion of particles below the hot metal surface were analyzed and compared. The numerical simulation results show that the new impeller can provide more axial speed than the traditional impeller. The staggered impeller and the high-low impeller enhance the dispersion degree of the desulfurizer, and their Sigma values wereproposed to quantify the particle dispersion are lower than those of the conventional impeller by about 9.49% and 14.18%, respectively. The average particle size of the desulfurizer after desulfurization is reduced by approximately 14.91% and 13.38%, respectively, compared with the traditional impeller conditions. A 300 t industrial experiment was carried out on the high-low impeller in the Baoshan base steelmaking plant of Baosteel Co., Ltd. Furthermore, the average unit sulfur consumption of the high-low type impeller was reduced by 0.27 kg compared with the traditional impeller in the same period.
[1] Emi T. Steelmaking technology for the last 100 years: Toward highly efficient mass production systems for high quality steels[J]. ISIJ International, 2015, 55(1): 36. [2] 彭家云,李明晖,欧阳德刚,等. 铁水KR机械搅拌脱硫反应动力学研究进展[J]. 炼钢,2022,38(2):11. (PENG Jia-yun, LI Ming-hui, OUYANG De-gang, et al. Research progress on desulfurization reaction dynamics of hot metal by KR mechanical stirring[J]. Steelmaking, 2022,38(2): 11.) [3] 朱仁林,李建立,余岳,等. 硫含量对KR脱硫渣中硫赋存状态的影响[J]. 钢铁,2022,57(2):54.(ZHU Ren-lin, LI Jian-li, YU Yue, et al. Effect of sulfur content on occurrence state of sulfur in KR desulfurization slag[J]. Iron and Steel, 2022, 57(2):54.) [4] 蒋佳君,李建立,朱仁林,等.冷却速率对KR脱硫渣中硫析出行为的影响[J].中国冶金, 2022, 32(3): 112.(JIANG Jia-jun, LI Jian-li, ZHU Ren-lin, et al. Effect of cooling rate on precipitation behavior of sulfur in KR desulfurization slag[J]. China Metallurgy, 2022,32(3):112.) [5] 文光华,许松,奚超超,等. KR法铁水脱硫剂利用技术研究进展[J]. 炼钢,2016,32(3):1. (WEN Guang-hua, XU Song, XI Chao-chao, et al. Research progress on efficiency techniques for desulfurization flux in hot metal with KR process[J]. Steelmaking, 2016, 32(3): 1.) [6] 刘飞,邹长东,马建超. 铁水温度和硅含量对搅拌法脱硫的影响[J]. 上海金属,2014,36(4):19. (LIU Fei, ZOU Chang-dong, MA Jian-chao. Effect of temperature and Si content of hot metal on desulfurization during mechanical stirring process[J]. Shanghai Metals, 2014, 36(4): 19.) [7] 吴明,李应江. 单喷、复喷、KR法脱硫工艺在马钢的实践分析[J]. 中国冶金,2008,18(12):9. (WU Ming, LI Ying-jiang. Practical analysis of desulphurization process of single grain magnesium,combined injection and KR method in Masteel[J]. China Metallurgy, 2008, 18(12): 9.) [8] 孙亮,朱良,赵晓东. 3种铁水脱硫工艺的应用实践[J]. 中国冶金,2018,28(3):50. (SUN Liang, ZHU Liang, ZHAO Xiao-dong. Application practice of three kinds of hot metal desulphurization process[J]. China Metallurgy, 2018, 28(3):50.) [9] Ito K, Yamamoto N, Kuranaga S. The evaluation of the mixing properties of the mechanically stirred cylindrical vessel[J]. ISIJ International, 2006, 46(12): 1791. [10] 叶裕中. 模型研究KR法的搅拌混合特性[J]. 钢铁研究学报,1992,4(1):23.(YE Yu-zhong. Study of the properties of agitated mixing of KR vessel by water model test[J]. Journal of Iron and Steel Research, 1992, 4(1): 23.) [11] 陈志平,章序文,林兴华. 搅拌与混合设备设计选用手册[M]. 北京:化学工业出版社,2004. (CHEN Zhi-ping, ZHANG Xu-wen, LIN Xing-hua. Mixing and Mixing Equipment Design Selection Manual[M]. Beijing: Chemical Industry Press, 2004.) [12] 张送来,郁青春,杨斌. KR法脱硫气液两相流的数值模拟与水模型试验[J]. 钢铁研究学报,2018,30(8):618. (ZHANG Song-lai, YU Qing-chun, YANG Bin. Numerical simulation and water model experiment of gas-liquid two-phase flow in KR desulphurization[J]. Journal of Iron and Steel Research, 2018, 30(8): 618.) [13] JI Jun-hong, LIANG Ru-quan, HE Ji-cheng. Simulation on mixing behavior of desulfurizer and high-sulfur hot metal based on variable-velocity stirring[J]. ISIJ International, 2016, 56(5): 794. [14] HE Mei-le, WANG Nan, CHEN Ming, et al. Distribution and motion behavior of desulfurizer particles in hot metal with mechanical stirring[J]. Powder Technology, 2020, 361(1): 455. [15] 申晓阳,李强,郭帅,等. KR预处理工艺参数对脱硫剂分散行为的影响[J]. 材料与冶金学报,2022,21(2): 109. (SHEN Xiao-yang, LI Qiang, GUO Shuai, et al. Effect of operating parameters on dispersion behavior of desulfurization reagent particles for KR pretreatment process[J]. Journal of Materials and Metallurgy, 2022, 21(2): 109.) [16] Blais B, Bertrand F. CFD-DEM investigation of viscous solid-liquid mixing: Impact of particle properties and mixer characteristics[J]. Chemical Engineering Research and Design, 2017, 118: 270. [17] 孙贞贞,但斌斌,牛清勇,等. KR法铁水脱硫搅拌流场的数值分析[J]. 炼钢,2019,35(6):1. (SUN Zhen-zhen, DAN Bin-bin, NIU Qing-yong, et al. Numerical analysis of stirring flow field of hot metal desulfurization by KR method[J]. Steelmaking, 2019, 35(6): 1.) [18] 欧阳德刚,刘守堂,罗巍,等. KR脱硫搅拌器结构参数的水模优化实验[J]. 钢铁研究,2010,38(2):8. (OUYANG De-gang, LIU Shou-tang, LUO Wei, et al. Optinization of structare parameters of KR stirrer by hydraulic simulating experiment[J]. Research on Iron and Steel, 2010, 38(2): 8.) [19] LI Meng, TAN Yang-bo, SUN Jiang-long, et al. Drawdown mechanism of light particles in baffled stirred tank for the KR desulphurization process[J]. Chinese Journal of Chemical Engineering, 2019, 27(2): 247. [20] 纪俊红,江禹,杜鸿贤,等. 桨叶形状对KR法脱硫混合行为影响的数值模拟[J]. 钢铁研究学报,2022,34(5):451. (JI Jun-hong, JIANG Yu, DU Hong-xian, et al. Numerical simulation of influence of impellers′ shape on mixing behavior by KR method desulfurization[J]. Journal of Iron and Steel Research, 2022, 34(5): 451.) [21] 贾舒渊,王强,贺铸,等. 桨叶结构对KR脱硫搅拌效果影响的数值模拟[J]. 钢铁研究学报,2021,33(11):1134. (JIA Shu-yuan, WANG Qiang, HE Zhu, et al. Numerical simulation of effect of blade structure on KR desulfurization stirring[J]. Journal of Iron and Steel Research, 2021, 33(11): 1134.) [22] Jain S V, Swarnkar A, Motwani K H, et al. Effects of impeller diameter and rotational speed on performance of pump running in turbine mode[J]. Energy conversion and management, 2015, 89(1): 808. [23] JIA Shu-yuan, HE Zhu, OUYANG De-gang, et al. Powder injection effect on hot metal desulfurization behavior in the kanbara reactor: A transient 3D coupled numerical model[J]. ISIJ International, 2022, 62(3): 449. [24] Nakai Y, Hino Y, Sumi I, et al. Effect of flux addition method on hot metal desulfurization by mechanical stirring process[J]. ISIJ International, 2015, 55(7):1398. [25] Nakai Y, Sumi I, Kikuchi N, et al. Powder Blasting in hot metal desulfurization by mechanical stirring process[J]. ISIJ International, 2017, 57(6):1029.
2023, Vol. 58 
