Simulation study of heat transfer and cooling enhancement measures for slag particles in granulation chamber

Abstract

The steel industry, being one of the major contributors to global energy consumption and environmental pollution, has drawn significant attention to the management of its by-products, especially the treatment of blast furnace slag and the recovery of waste heat. Centrifugal granulation and waste heat recovery technology are considered the most promising solutions. However, their development is constrained by the limited heat exchange space within the granulation chamber, resulting in insufficient cooling rates for the granulated particles. This ultimately threatens the safe operation of the system. In this study, we established a heat exchange model for a granulation chamber that integrates various structures and enhanced cooling measures, investigating the flight heat exchange characteristics of particles within the chamber. The results indicate that setting the granulation chamber wall angle to 0° and maximizing the granulator height within the limited space can extend the impact time of slag particles by more than 0.2 s. Positioning the air outlet at the center and limiting its width to within 200 mm increases air flow resistance, further reducing the slag particle outlet temperature by 15 K. Side and edge winds increase the solid phase fraction of particles at exit by 20 % and 6 %, also reduces the impact wall temperature by 9.56°C and 3.37°C,demonstrating the significant advantages of enhanced cooling measures. This study provides guidelines and standards for the structural design of granulation chambers in industrial applications and offers a new perspective on enhanced cooling measures to prevent wall adhesion.