Numerical study on solidification behaviors of a molten slag droplet in the centrifugal granulation and heat recovery system. (5th February 2018)

• Record Type: Journal Article
• Authors: Zhu, Xun; Ding, Bin; Wang, Hong; He, Xian-Yan; Tan, Yu; Liao, Qiang
• Is Part Of: Applied thermal engineering. Volume 130(2018)
• Page Start: 1033
• Page End: 1043
• Publication Date: 2018-02-05
• Subjects: BF slag droplet -- Variable cooling conditions -- Solidification behaviors -- Crystal phase content; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2017.11.080
• Languages: English
• ISSNs: 1359-4311

Abstract

Graphical abstract: Highlights: Enthalpy method is adopted to analyze the solidification of a slag droplet. Effect of the variable cooling conditions on the solidification is taken into account. Evolutions of temperature and crystal phase content inside the droplet are obtained. Economic operating parameters of the heat recovery system are obtained. Abstract: Centrifugal granulation technique is the most feasible method for heat recovery from molten blast furnace (BF) slag. The granulated slag droplets experience a complex cooling process to achieve a glassy phase for cement clinker. In the present study, an enthalpy-based model is established to investigate solidification behaviors of a molten BF slag droplet cooled in the centrifugal granulation and heat recovery system. Moreover, influences of droplet flying speed and time in the flying process, heat transfer coefficient and cooling air temperature in the primary fluidized bed as well as droplet initial temperature and diameter are discussed on the solidification behaviors of the BF slag droplet. The numerical results indicate that the temperature of droplet outer surface successively experiences a rapid drop in the flying process, rebound and then gradual decrease in the primary fluidized bed due to the variable cooling condition. Moreover, for a specific granulating device as well as the slag droplet with diameter of 5 mm and initial temperature of 1673 K, the condition with heat transfer coefficient of 50–76 W·m −2 ·K −1 and cooling air temperature of 889–973 K are the optimized cooling conditions for the heat recovery stage to satisfy the multiple goals.