SU1004473A1 - Method for controlling supply of reducer gas to blast surface - Google Patents

Description

The invention relates to ferrous metallurgy, in particular to the regulation of the technological process of cast iron smelting in blast furnaces.

There are known methods for regulating the supply of reducing gas to a blast furnace, in accordance with which the amount of gas is determined by the parameters of the combined blowing. For example, at the Chel Beinsk Metallurgical Plant, natural gas is regulated in such a way that the ratio of its consumption to oxygen consumption is maintained within l / 2-l ,.

The above methods are not effective enough because they do not take into account the degree of use of the reducing gas in the furnace {the amount of carbon replaced by coke. When natural gas is supplied to the blast furnaces of the plant The Dzerzhinsky degree of utilization of hydrogen utilization ranged from 0.25 to 0.50, causing a change in the coef ficient ratio of coke with natural gas of 0.607 to 1.02 kg / m. As a result, the efficiency of the use of natural gas, the thermal state of the furnace, and the chemical composition of the pig iron fluctuate.

Closest to the invention of the technical essence and the achieved results is a method of regulating the flow of natural gas into the shaft furnace. In accordance with this method, the amount of reducing gas is maintained at an extreme level corresponding to the maximum reduction in the consumption of conditional coke. At the same time, the consumption of conditional coke is equal to the amount of coke that is charged for the reducing gas, minus the consumption of conditional coke, equivalent to the cost of the reducing gas and oxygen C2J.

However, this method is also not sufficiently effective, since it does not take into account the influence of the degree of use of the reducing gas in the furnace on the amount of coke carbon replaced and, consequently, on the thermal composition of the process.

The purpose of the invention is. increasing the efficiency of supplying reducing gas to the blast furnace and improving the quality of cast iron.

25

The goal is achieved by the fact that the amount of reducing gas is maintained at an extreme level corresponding to the maximum savings of conditional coke, according to

30 measurements of the flow rate and the composition of the combined blowing, the chemical composition of the top gas determines the carbon change of the BOSS coke gas and its deviation from the previous value and, if there is a deviation, change the ore load on the coke. The proposed method is carried out as follows. When supplying a blast furnace of a reducing gas, the composition (fl,) and the amount v of reducing gas, the amount of blowing V, and the oxygen PP / humidity blowing A, the number of feeds of materials loaded into the furnace, the composition of the top gas (CO, CO2, H ). From the averaged values of the measured parameters during the time t within 10–60 min, the amount of coke carbon, ES, is calculated, which is replaced by the reducing gas (3021gT Co-2580 CNYVgt t (l 1.866 (1254 + 3021 | p)) and the savings coke from the use of the combined Yt 3021 G1co + 2580 | C | Chn4. - degree of utilization of water with hydrogen and carbon monoxide, fractions of a unit, C - carbon content in coke, fractions of a unit, K, K - coefficients equivalent to carry natural gas and oxygen to coke, respectively, 3021 is the amount of heat produced during oxidation of CO to CO, kcal / m, 2580 is the amount of heat absorbed during oxidation of H to H2O, kcal / m ; i; 866 2 || i., 22.4 is the Avagadro number, 12 is the molecular weight of carbon 1254 is the amount of heat released by oxidation of С to CO, kcal / m. setting the consumption of reducing gas changes its amount to an extreme value corresponding to the maximum savings of conditional coke, and maintains the flow rate d reducing gas at an extreme level. The change in the amount of carbon of the coke replaced by the reducing gas, compared with the previous period of averaging LES Er (t) -3e (t-1), is determined. Change the mass of the coke bed by the value of Ak -, - L P where n -, the number of feeds of charge materials and fuel loaded into the blast furnace during normal operation during time t. If) k) 100 kg / feed, then the mass of the coke quantity is changed by 100 kg in the following number of feeds% c.1oo. Example, a domain furnace with a useful volume of 1754 m of it. Dzerzhinsky smelted pig iron. A 3670 blown oxygen-enriched 67.6 m / min oxygen and 123.3 m / min natural gas is blown into the furnace and 10. feeds of charge materials and coke are charged in 60 minutes. Natural gas has a chemical composition: / 4 2.06; AG 1.077. The table shows the values of the measured parameters, the calculated indicators and the operations performed to search for the optimum consumption of natural gas and stabilize the thermal state. The search for extreme values of natural gas consumption is increased by the consumption of natural gas in steps of no / vl6.00 every 60 minutes. From the first to the third step, with an increase in the amount of natural gas, the savings of conventional coke increase, so that the consumption of natural gas also increases. At the fourth stage, after an increase in the amount of natural gas, the saving of conditional coke decreases as compared with the previous value of 12.58 kg / min. Therefore, in the fifth step of the search, the consumption of natural gas is reduced, and this makes it possible to obtain maximum savings of conditional coke. Thus, in the given conditions, the consumption of natural gas 173.3 is extreme, corresponding to the maximum savings of conditional coke. When searching for the optimum consumption of natural gas, the amount of coke carbon that is replaced by natural gas is determined. After the first step of increasing the consumption of natural gas, the amount of coke carbon replaced increases, and measures are taken to reduce the mass of the coke bed by an average of 123 kg. Similar reductions in the mass of coke in the feed are made after the second and third steps of increasing the consumption of natural Haz,

After the fourth step of the natural gas consumption, the amount of coke carbon replaced is reduced. Therefore, in order to stabilize the heat state of the furnace in two feeds, add -. 100 kg of coke.

After the fifth step, with a decrease in the consumption of natural gas, the amount of replaced coke carbon increases, therefore, in two feeds, the mass of coke coal is reduced by 100 kg.

The application of the proposed method allows to increase the efficiency of the reducing gas, to reduce the coke consumption by 0.5%, respectively, to increase productivity and to improve the quality of cast iron. The expected economic effect from the implementation of the method is:

yuo C 0666oo.44- fo6660o 2.117

l-WnS PVE ..

0.5

specific decrease

where coke consumption and productivity increase after implementation of the method,%;

510 specific consumption of coal, kg / t of iron;

1066600 year capacity of blast furnace, t

44 cost of coke, RUB / t;

five

2.71 conditionally fixed costs for pig iron, RUB / t.

Claims (1)

Additional efficiency is obtained by stabilizing the composition of the iron. . Claims The method of controlling the supply of reducing gas to a blast furnace including changes in the flow rate of the reducing gas with time intervals between them and the subsequent change in the consumption of conditional fuel for Si content in cast iron, in order to ensure the maximum rate of coke carbon replacement for smelting, the reduction gas and coke yield are varied in terms of the coke carbon replacement ratio according to the following relationship (30217ГПсо + 2 | 0 1 1c) 1, + 3021Г) where E is carbon saving ks and - degree of Co use of hydrogen and carbon monoxide, fractions of a unit, JH, f amount of hydrogen and carbon monoxide formed in the furnace from 1 m of reducing gas, amount of reducing gas fed to the furnace, nV minJ t - averaging time of measurement results, min} 3021 the amount of heat released during the oxidation of CO and CO.J, kcal / m; 2580 the amount of heat released during the oxidation of Hi to NO, kcal / m. , 1.866 12 ... 22.4 - Avagadro number 12 - molecular carbon carbon; 1254 is the amount of heat released during oxidation of C to CO, kcal / m. Sources of information that are considered in the examination. Report on the research work of research and development B 147 635. Chel Binsmetallurgical Plant. 1975. E. Tikhomirov Combination of blast furnaces. M., Stroyt. 1974, p. 69, fig. 31.