SU910766A1 - Process for conditioning blast furnace melting - Google Patents

Description

(5) METHOD OF MAINTAINING A DOMAIN MELT

I

. The invention relates to ferrous metallurgy, in particular to the domain production, and can be applied in the smelting of iron.

There is a known method of conducting blast-furnace smelting with blowing nitrogen or an inert gas through lances with a temperature in excess of more than 8S from the heated atmospheric blowing G13.

The disadvantage of this method is the deterioration of indirect recovery processes in the mine.

A known method of operating a blast furnace, in which, in order to reduce coke consumption, it has been proposed to blow nitrogen into the tuyere tuyeres in an amount of kd% of the heated volume to blow G23.

The closest to the invention to the technical essence is the method of blast furnace smelting, including loading of iron ore charge, fluxes and fuel through the throat, blowing heated atmospheric blowing and nitrogen into the tuyeres while

entering into the mine heated reducing gases. The temperature of the hot blast in a known method is kept constant at any flow rate and the nitrogen added, i.e. the heat output of the air heaters is fully utilized in all operating modes of the blast furnace, 31.

The disadvantage of this method is to significantly reduce

10 intensity of reduction of iron oxides and, consequently, a decrease in productivity at a rather high consumption of coke (productivity 1.67 t / min, consumption of coke 719 kg / t

cast iron ts). .

The aim of the invention is to increase the efficiency of blast-smelting.

The goal is achieved by the fact that according to the method of maintaining

Claims (1)

20 blast furnace smelting, including loading of iron ore charge, fluxes and fuel through the throat, blowing heated atmospheric blowing and nitrogen 39 into the tuyeres while simultaneously charging reducing reducing gases into the shaft, blowing 50 to 70% of the heated atmospheric blowing into the shaft and heating consumption reducing gas is set according to the formula: Ub, g. - 1.624 (K - DK), where is the consumption of reducing gas required for indirect reduction of iron from agglomerate nm / t of pig iron; - coke consumption, kg / t pig iron; - coke consumption on the corner of the birth of iron and removal through the throat, kg / t of iron; 1,624 - gas output from burned in coke, coke tuyeres. The method includes the loading of iron-containing materials, fluxes and fuel through the throat and the supply of hot blowing through the tuyeres and injecting an inert gas, for example nitrogen, into it, and also injecting the heated reducing gas into the mine. Inert. gas is blown in the amount of 50-70 of the volume of hot blowing, and the flow rate of the heated reducing gas in the mine is established from the specified ratio. The stable process of burning the carbon of coke in the furnace is carried out at the oxygen content in the blast, which corresponds to the consumption of inert gas (nitrogen). When the oxygen concentration is more than 10, corresponding to the lower limit of the nitrogen content (50), the efficiency of smelting decreases. In the blast of less than 5 Oi, corresponding to the upper limit of nitrogen 75, the combustion at the tuyeres becomes unstable. Thermal value of 1 kg of carbon (temperature blowing 1200 ° C) when the content in the blast is 10 0 (2 2502 kcal, and at 5 2834 kcal / kg, which is higher against kcal / kg for atmospheric blowing. Thus, due to heat, blowing can be reduced coke consumption for iron smelting. When the oxygen content in the blast decreases, the burning intensity of the coke carbon in the furnace hearth and, due to the decrease in the concentration of reducing gases (CO} from 34.7 to 9.52-18.18%, decreases intensity of the reduction of iron oxides in the mine. According to the stereotypical ratio for the recovery In iron from hematite for 1 ton of iron, it is necessary to use 564 m of reducing agent (CO) by the reaction FenOa + + SOO 2Fe + SOU. When indirectly reducing, the average utilization of reducing agents is 40%, i.e. the consumption of reducing agents for 1 ton pig iron is equal to 1410. m or furnace gas 14810 and 7756 m, with 5 and 10 oxygen content in the blast, respectively. Because through the top of a blast furnace with a volume of 20,000 m (throat diameter 7.5 m) with a pressure below the brim, equal to 2 ATA, passes 6b2b NT gas in 1 min without disrupting the furnace, then produce nost furnace is 0.45 and 0.85 m / min to 5 and oxygen into the blast, respectively, the amount of heat It appears excessive. To ensure an acceptable level of performance with low coke consumption, a heated reducing gas is blown into the blast furnace shaft, the flow of which is equal to the difference between the amount needed for the reduction of iron and that produced by burning in the furnace, i.e. at the specified ratio. Example. Iron-containing materials containing 16.78 kg-moles of iron per 1 ton of pig iron and 2bO kg of coke per 1 ton of iron are loaded through the top furnace. Hot blast is blown in through tuyeres containing 101 oxygen (501 nitrogen to the volume of hot blowing) heated to 1240 ° C in an amount of 1–25 m / t of pig iron, which provides for the formation of 328 m of reducing agents in the hearth. The required amount of reducing gas for feeding into the mine is determined from the indicated ratio: V 1410, 624 (260 - 58) 1082 m / t of pig iron, where 1410 is the consumption of reducing gas required for indirect reduction of iron from matite, nm / t of cast iron, 0, 87 22.4 1.624 yield of kg of coke-reducing gas from ca., nm / kg. coke; 0,87 carbon content In coke, fractions of a unit ;, 22.4 - the volume of kg-molecule,. nm / kg-mol, 12 — weight of 1 kg-mol of carbon, kg 58 — coke consumption for carbonization of pig iron and removal through the collar, kg / t of iron. In this case, the following amount of flue gas is formed: 1.1 + 1082: 0.90 1787 + 1202 2981 pig iron, where 1.1 is the gas output from 1 meter blow, 0.9 is the content of reducing components in reducing gas, the fraction of units nice Hot blast is introduced into the forge, 1625x12 0x0, kcal warm. When burning the coke, (260–58) 0.87 23 + 0 i | 1 1232 kcal of heat is released in the furnace. Reducing gas. charred up to 900 ° C, makes 0.3b7x 1082 h900 357060 kcal of heat. A total of 694362 + L1.1232 + 337060 14b2b54 kcal of heat is applied for smelting 1 ton of pig iron. Heat consumption for pig iron smelting is: for heating and melting pig iron for kcal, for heating and melting slag CtOO kg / t of pig iron) for kcal, for heat loss through masonry 200,000 kcal; to direct restoration of elements and transfer of sulfur to slag 250000 kcal. Total: + 17ttOO +.200000 + + 250000 kcal. In addition, part is carried away through the top: 1 462654 - ii9825 kcal. Such a Tenha mixture provides the heat content of the top gas:, 1–7 kcal / nm, which corresponds to a temperature above 455 ° C, i.e. There is a considerable reserve of heat that can be realized by reducing the consumption of coke or reducing the heating of the reducing gas. The theoretical temperature in the horn is about 1900 ° C. The consumption of iron ore for smelting 1 ton of pig iron is about 9,700 kg, then the ore load is 1700, .... J / ,. 0.5 t / t of coke. Furnace capacity: em em 000 m (throat area 41.8 m) at a pressure under the throat 2.5 MPa at an acceptable gas flow rate of 0 m / min per 1 m of the throat section) 1,, о. 3330 t / day or 2.9 t / min, de 3.3 - absolute gas pressure under the furnace top, ati, 50 - gas consumption, m / m of top section; 41.8 - top section, 2981 - collar outlet of inik gas,. HMVr cast iron; lt40 - the number of minutes per day. The productivity of this manual is higher in relation to the known2, 3-1.67 100 37. I am blown at an expense of 11 1625 3758 m min. The entrance into the reducing gas to the shah || 5- X 1082 2502 or 50127 MV4. flue gas is made, || g-x 2981 6893, or MV MVO. onomic effect of smelting E (0.500 - 0.260M5-1.0852 -8.5 10.8 - 9.2 1.6 rubles / t, e 0.5 and O, 2b - coke consumption before and after the introduction of the technology, t / t of pig iron, 45 - coke price, rubles / t; 1,0852 - reducing gas consumption, 1000 pig iron; 8.5 price of reducing gas obtained by conversion of natural gas, rubles / 1000 m. Invention The method of managing blast-furnace smelting, switching to iron ore loading 791076 you, flux and fuel through the throat, blowing into the tuyeres of heated atmospheric blowing and nitrogen, while simultaneously introducing into the mine the heated reducing gases, so as to so that, in order to increase the efficiency of smelting, nitrogen in the amount of BO-UB from the volume of heated atmospheric blowing is blown into the furnace, and the flow rate of the heated reducing gas into the mine is set according to the formula: Vftr - 1.62 (K - DC), where - consumption of reducing gas, necessary for indirect reduction of 5 10 15 iron from hematig, im / t of pig iron K; coke consumption, kg / t of cast iron; K - consumption of coke for carbonization of pig iron and removal through the throat, kg / t of iron; 1.62A - gas output from coke burned at tuyeres, Sources of information taken into account during the examination. Japanese Patent fP kQ-k685, 10522 (F 27 1/00), 02/10/73. . Japanese patent 10 А 52, (С 21 В), 03.06.72. . French Patent No. 12566501, C 21 B 5/00, 1972.