| In China,the steel industry is an important pillar industry,and China’s steel output has remained the world’s number one year round.During the smelting process of steel,a large amount of high temperature slag waste is generated.Its temperature is as high as 1400～1600℃,which contains a large amount of high-grade sensible heat resources,which has great recycling value.At present,the main treatment method for slag by domestic steel companies is the water quenching method.This method not only cannot recover sensible heat resources,but also causes atmospheric pollution and wastes water resources.Therefore,the dry granulation waste heat recovery process has become a research focus in the field of slag treatment.This paper aims at the waste heat recovery process of blast furnace slag by the centrifugal granulation method.The flying process of the broken blast furnace slag particle group in the granulation chamber is taken as the research object.The numerical simulation method is used to explore the whole process of flight,heat transfer and solidification of the particle group in the chamber.During the research,Fluent software was used to establish a model for the flight heat transfer of blast furnace slag particles in the granulation chamber and the solidification of blast furnace slag particles.The influence of cooling air velocity,initial temperature of slag particles,initial speed of slag particles,slag particle diameter,and slag mass flow rate on the flight,heat transfer and solidification of blast furnace slag particles was studied.The main results are as follows:(1)Based on the actual process of centrifugal granulation of blast furnace slag,a model of blast furnace slag particle group flight and heat exchange in the granulation chamber was established,and a model of blast furnace slag particle solidification was established.(2)The slag mass flow rate and initial temperature have no effect on particle movement.Increasing cooling air speed and reducing particle diameter will delay the time when particles reach the wall and leave the granulation chamber.Increasing the initial speed of the slag particles will cause the collision time of the wall surface is advanced,but the residence time of the particles in the chamber is increased first and then decreased.(3)Increasing the mass flow rate and the initial temperature of the slag particles will increase the temperature in the granulation chamber.Increasing the particle diameter and air velocity will decrease the temperature in the granulation chamber.Increasing the initial velocity of the particles will reduce the temperature in the upper half of the chamber but increase the temperature of the lower part of the chamber.(4)During the solidification progress of the particles,the shell of the particles will rapidly cool.During the flight of the particles,the shells have solidified when they reach the water-cooled wall,but the core of the particles has not completely cooled until they leave the granulation chamber.(5)Increasing the cooling air speed will increase the thickness of the solidified layer when the particles reach the wall and leave the granulation chamber.Increasing the initial slag temperature,particle diameter and slag mass flow rate will reduce the thickness of the solidified layer when the particles reach the wall and leave the granulation chamber.Increasing the initial velocity of the particles will reduce the thickness of the solidified layer when the particles reach the wall surface,but the thickness of the solidified layer will increase and then decrease when leaving the granulation chamber. |
