Study On Jet Thermal Separation Of Coking Coal And Coking Characteristics Of Separated Coal

As a pillar of domestic equipment manufacturing industry,the output of iron and steel reached 10.33 billion tons in 2021,accounting for 54%of the world.At the same time,carbon emissions of iron and steel industry accounted for 15%of the total domestic carbon emissions,and coking industry accounted for 30%in this industry.Therefore,under the requirements of the national“double carbon”strategic goal,it is necessary to improve the technological level in accordance with the current situation of the coking industry.Coal moisture control technology,as a technical measure to reduce the moisture content of charging coal and reduce the heat consumption of coke oven,has been constructed in domestic coking plants.However,the wide application of coal moisture control technology in China is limited due to the technical problems such as the pollution of pulverized coal,the increase of tar residue and the difficulty of separation.This paper mainly studies the separation characteristics of coking coal by cyclone and jet separation technology,which provides an important technical route for moisture control technology of coking coal in China.Based on the review of technologies such as coking coal moisture control at home and abroad,the integrated experimental platform of coking coal cyclone moisture control and thermal separation was constructed by using the technology that combines cyclone moisture control and jet separation,and the control of hot air process parameters was studied.The separation characteristics of GY coking coal,BBG lean coal,FGZ fat coal and DSHS1/3 coking coal were tested.The relationship between gas flow at the inlet of cyclone humidifier and jet separator and pressure and temperature was discussed.The separation efficiency of coking coal is obtained.The forming performance of particles less than 0.5 mm in coking coal was studied by forming coal process,and the experimental coking experiment was carried out.At the same time,modern instruments such as modern pore size analyzer,polarizing microscope,mercury porosimetry and scanning electron microscope SEM were used to study the coking characteristics and microstructure properties of separation coal.In addition,the performance of coke made in the experimental coke oven after thermal molding of coking coal and the influence of density change of different coal stacks on the micro and macro strength of coking coke were studied.The results show that when the fineness of raw coal is 80%,the particle size is 0 mm～3 mm,the gas temperature of the cyclone humidifier is 140℃～200℃ and the inlet wind speed is3.38 m/s～4.51 m/s,the inlet wind speed of the jet separator is 12.73 m/s.The experimental device has the most stable separation operation of coal.At the same time,the separation efficiency of coking coal can be stabilized at 79%,and the moisture content of coking coal can be adjusted to 0.3%～2.5%.The optimal process conditions of separation efficiency are realized.The influence of coal moisture,molding temperature and other factors on the molding performance of coking raw coal less than 0.5 mm obtained by jet separation was studied.In particular,experimental coke oven coking experiments were carried out on briquette.The results show that when the hot forming temperature is 300℃,the pressure resistance of the formed coal is the largest,reaching 22.89 N.Compared with the strength of the formed coal with conventional water content of 10%,the pressure resistance of the formed coal is increased by 43.5%,and the pressure resistance of the formed coal is increased by53.7%compared with that of the dry fine coal formed by cold pressing.The hot formed coal shows an obvious advantage in strength performance.In addition,the performance of the coke prepared in the coking experiment of blended coal shows that the density of the charging coal heap is increased by about 12%compared with that of the conventional coking process when the hot pressing briquette is used for coking of blended coal.At the same time,when the moisture content of the separated coal reaches 0.8%,the coking time can be shortened by about 15 min,accounting for12.5%of the coking time of wet coal.In particular,the coke oven coking experiment of coal separation shows that the coke micro-strength can be increased by 6.79%,and the structural strength can be increased by 10.48%.At the same time,the coke reactivity is reduced to 8.63%,and the maximum strength after coke reaction can be increased by 25.45%.In the experiment,the pore size distribution,porosity,SEM and other modern instruments of the formed coal coking experiment of conventional coking and moisture conditioning separation of fine coal were characterized,indicating that the coking structure characteristics of coal after jet separation were characterized by many micropores,and most of them were closed pores.At the same time,the internal structure of the coke matrix was regular and orderly.In addition,the graphitization degree（r₀）of the coke produced by the thermal forming coking experiment of separated coal increases.Therefore,the coking coal pretreatment technology carried out in this paper,which combines the cyclone humidity control and separation of coking coal,has high separation efficiency,and the micro-strength and thermal performance of coke obtained from the coking application of the fine-grained coal after molding show excellent process performance indexes.