Design And Research On Preheating System Of Hot Blast Stove For High Temperature

With the ironmaking technology progress,the BF gas depletes and heating values decrease,while the fules with high heat value lack like coke oven gas.Under this situations,enhancing hot blast temperature and thermal efficiency will be an important topic in order to save energy and increase pulverized coal injection in the ironmaking process.In this thesis,the blast temperature present situation of iron and steel industry in our country is investigated and the main reasons of low blast temperature are analysed.And putting forward to the preheating technology to warm up the air and gas is a good approach to gain the high blast temperature of hot blast stove.This thesis bases on the problem which is low blast temperature of hot blast furnace in No.4 BF at ironmaking plant.Its running states and limitation factors of blast temperature increasing are analysed through thermal efficiency diagnosis test.On this basis, discussing at the present of BF gas situation,adopting the additional burner double preheating system process rebuilds the blast system of hot blast stove.Including designing the double preheating system processing flow,thermal calculation and type choice and designing of the main equipments such as combustion furnace and heat exchanger.At last,the double preheating system is studied and economic profits of putting into production are reckoned.Double preheating system designed in the actual application confirms that hot blast stove that burns 100%BF gas can entirely reach the anticipation target of 1200℃,the thermal efficiency of hot blast stove reaches more than 79%,and waste gas temperature reduces from 260℃to 140～170℃.The BF for high blast temperature can be met,the heat resources of waste gas are recovered and the comprehensive utilization of waste gas is realized.