Simulation And Optimization Of Temperature Field In Sintering Process

As an important process in the process of blast furnace ironmaking,sintering block has the characteristics of long flow,many links,large energy consumption,large flue gas emission and bad environment.In order to solve the above problems,it is necessary to study the change of heat and mass transfer inside the sintering process to improve and optimize the sintering process.In this paper,Xining special steel 150m~2sintering machine as the research object,on the basis of the analysis of heat and mass transfer during the sintering process to establish a reasonable mathematical physics model,through the material characteristics analysis and actual operation parameters as information input,the established model in Fluent for the sintering process simulation calculation.The influence law of each important parameter on the temperature distribution of the bed and the sintering end point in the sintering process is obtained,and the parameters are optimized and adjusted to get the best process parameters,which provides scientific theoretical guidance for the actual production of Xining special steel sintering.The main conclusions are as follows:(1)From the temperature cloud map of the bed section,as the sintering time goes on,the combustion part moves slowly from top to bottom,which accords with the temperature change of the bed during the actual sintering process.By measuring the actual value of the flue gas temperature in the field and comparing it with the simulated data,the error source is reasonably analyzed,and the correctness of the simulation results is verified.(2)The effect of ignition temperature,carbon content,porosity and layer thickness on the temperature distribution of the layer during sintering with sintering time was studied by single factor analysis.The results showed that the extreme temperature of the surface of the layer increased with the increase of ignition temperature from 1223K to1423K,and the effect was not significant in the range below 450mm.The carbon content increased from 4.2%to 4.6%,the extreme temperature at the bottom of the bed increased from 1355.98K to 1620.12K,and the maximum temperature on the surface of the bed did not increase significantly.With the increase of porosity,the heating rate of the bed will increase,the heat exchange between the gas-solid phase will be intense,the self-heat storage effect of the bed will also be strengthened,the chemical and physical reaction efficiency will be greatly improved,and the sintering time will be shortened to about 1500s.The thickness of the bed increases from 600mm to 1000mm,the sintering time is extended,the combustion zone is thickened,and the maximum temperature of the bed below the height of 600 mm has little effect.(3)The actual sintering terminal time calculated by bellows exhaust gas temperature method is compared with the numerical simulation method,and the error is1.17%.The effects of carbon content,porosity,layer thickness and negative air pressure on the time required to reach the sintering end point were studied by single factor analysis.The study shows that the sintering end point time becomes shorter when the carbon content is increased,and the sintering end point is in a good position when the carbon content is 4.23%.When the porosity of the bed is increased,the sintering terminal time is shortened.When the porosity is about 0.49,the sintering terminal position is good,and the vertical sintering rate per unit porosity is higher.When the thickness of the bed is 734.13mm,the maximum vertical sintering speed is 0.321mm/s.The increase of suction negative pressure can also shorten the time required for the sintering end point and improve the vertical sintering speed.When the suction negative pressure is 15kPa,the vertical sintering rate per unit suction negative pressure is larger,and the energy utilization rate of the sintering machine is larger.