Experimental Study On Improvement Of Pulverized Coal Combustion And Improving The Pulverized Coal Injection Ratio Of The 4000 M~3 Blast Furnace To 170 Kg/t In Masteel

In recent years,due to the shortage of coke resources and the increasing pressure of steel industry on environmental protection,it is particularly important of blast furnace to achieve the goal of enhance output and reduce energy consumption.With the rapid development of blast furnace ironmaking process and the maturity of pulverized coal injection technology,the pulverized coal injection ratio of some blast furnaces in domestic key steel industry have reached the level of 160~200 kg/t.However,since2017,the pulverized coal injection rate of the 4000 m~3 blast furnace in Masteel is relatively low,it has remained at about 140 kg/t for a long time.It is show that the pulverized coal injection rate of the 4000 m~3 blast furnace in Masteel still lag behind,compared with the pulverized coal injection ratio level in domestic.Therefore,it is necessary to further improve the pulverized coal injection ratio of the 4000m~3 blast furnace in Masteel.While increasing the pulverized coal injection ratio,the reduction of pulverized coal combustion rate will lead to waste of resources and deterioration of blast furnace smelting conditions.In this paper,the basic properties and combustion property of ten kinds of pulverized coal were studied to improve the combustion of pulverized coal The metallurgical properties of coke were measured,and the properties of coke were compared with those of coke used in same type advanced indexes blast furnaces at Baosteel and Meisteel.On this basis,the operation of high pulverized coal injection ratio of the 4000m~3 blast furnace in Masteel was studied and analyzed.The conclusions are as follows:(1)Bituminous coal has the highest combustion rate and medium grindability,but bituminous coal is explosive and unsafe of blast furnace injection.Hard coal has low combustion,high hardness and no explosion.Soft coal has high combustion,low hardness and no explosion.(2)The combustion rate of different pulverized coal under different granularity,air temperature and oxygen enrichment were studied,it can be obtained:for mixed coal,the ratio of-200 mesh coal granularity increases by 10%or the oxygen enrichment increases by 3%or the air temperature increases by about 33.3?,and combustion rate increases by about 1.30%.(3)The combustion rate of pulverized coal is increased by gradually increasing oxygen enrichment rate and hot air temperature,the oxygen enrichment rate increasing from 2.89%to 3.77%,and the hot air temperature increasing from 1196?to 1222?.Adjusting the proportion of pulverized coal injection,the proportion of soft coal in mixed coal is increased from 29.82%to 34.82%,the proportion of hard coal is reduced from 27.60%to 22.60%,the proportion of bituminous coal is unchanged,and the ratio of pulverized coal injection is increased from 140 kg/t to 160 kg/t.(4)Increasing the grain size and quality of coke.Adjusting the charging system,controlling the marginal gas flow,stabilizing the development of central gas flow to improve the utilization rate of gas in blast furnace,the ratio of pulverized coal injection is increased from 160 kg/t to 173 kg/t,and fuel ratio is reduced.