Magnification Of Steam Kinetic Energy Mill Based On Ultra-fine Pulverization Of Steel Slag

Nowadays,China's steel slag and steel mills have low utilization of waste heat and low utilization rate.The untreated steel slag has low activity and limited use and dosage.To increase the activity of steel slag,it is necessary to superfine the steel slag to less than 10 ?m,and the energy cost of the conventional pulverization process is too high.The steam kinetic energy grinding can ultrafine the steel slag particles to less than 10?m.The residual heat of the steel mill can be used as the pulverizing medium,but it is only realized on the experimental machine,and no large steam kinetic energy grinding is used to produce the ultra-fine steel slag powder.In order to improve the utilization rate of residual heat of steel slag and steel mill,this paper enlarges the scale of steam kinetic energy grinding on the basis of testing machine,and the key problem of scale enlargement is to determine the distance between nozzles.In this paper,the key problems of steam kinetic energy grinding scale amplification are studied by using Fluent software.The Reynolds Mean Method(RANS)was used to simulate the nozzle free/pair jet flow field at different magnifications.At the same time,the acceleration characteristics of the single particle at the axial center position were studied.The annual consumption was designed under the optimal particle acceleration distance.The steam kinetic energy grinding with a steam volume of 100,000 tons and the calculation of the internal gassolid two-phase flow field using the Euler-Eulerian two-fluid model have the following conclusions:(1)When the inlet pressure is 0.5 MPa and the temperature is 280 °C,the length of the free jet core zone formed by different nozzles is 15 times the throat diameter;the distance between the nozzles is 40 times the throat diameter to ensure that the length of the jet core zone is not less than 15 times.And the end of the jet velocity decay region is narrower;40 times the throat distance from the nozzle.(2)When the nozzles are separated by 40 times the throat distance,the particle acceleration characteristics are consistent with the free jet,the maximum speed of the particles is similar;the nozzle throat diameter is doubled,and the speed of the same kind of particles is increased by 50-100 m/s;the nozzle throat diameter is increased.The steam kinetic energy grinding of ?6.85 mm is not easy to accelerate the steel slag particles with particle size ?100?m.(3)The enlarged steam kinetic energy mill contains 6 nozzles with a throat diameter of 27.4mm,the steam consumption per hour is 14 tons,the airflow velocity in the crushing zone of the equipment can reach 945m/s,the swirling flow in the classification zone is clear,andthe height-to-diameter ratio of the classifying wheel At 0.5,the radial velocity distribution is not as uniform as 0.25,but the value is small,the updraft has less effect on the grading wheel;the spatial distribution of the particles is more uneven with the increase of the particle size,and the acceleration law of the particle group is consistent with the single particle;The position of the material inlet has an influence on the particle volume fraction of the core of the jet.The larger the particle,the more difficult it is to enter the jet of the nozzle far from the feeding port;the small particles are easily affected by the turbulence of the airflow,and the easier it is to enter the core of the jet to obtain higher speed.