SU1668402A1 - Method of control of blast furnace heat conditions - Google Patents

Abstract

The invention relates to ferrous metallurgy and can be used on blast furnaces. The aim of the invention is to reduce the specific coke consumption by increasing the accuracy and reliability of estimating and controlling the heating of the furnace. The heat level of the hearth furnace is determined by the total deviation of the chemical and physical exergy of cast iron, caused by measuring the silicon content in the iron and its temperature, and the regulating effects are performed when the sign of both deviations coincides, and the deviation of chemical exergy is 2 to 5 times greater than the deviation physical exergy with a total value of their deviation of more than 50 MJ / t of pig iron. The implementation of the proposed method improves the accuracy and reliability of estimating and regulating the thermal regime of the blast furnace melting, which makes it possible to reduce the average silicon, sulfur and manganese content in the pig iron by 0.08, 0.002 and 0.04%, respectively. A 0.1% reduction in silicon content in pig iron yields a coke saving of 3–5 kg / t of pig iron, a decrease in sulfur content by 0.01% - 5–7 kg / t of cast iron. Taking into account only the reduction of silicon and taking the previous value around the reduction, coke saving is 312 kg / t of pig iron. 1 hp ff.

Description

The invention relates to ferrous metallurgy and can be used on blast furnaces.

The purpose of the invention is to save coke.

The essence of the proposed method is as follows.

Reliable assessment of the heat state of the furnace and its effective management are possible when the parameters characterizing it — the temperature of the cast iron and the silicon content in it — are combined into one complex indicator. The use of enthalpy for this purpose is impractical, since one and

The same amount of heat is of unequal value due to different temperature potential. The performance of heat is determined by the value of exergy.

Chemical exergy of cast iron can be calculated by the formula

Ex 2Mi -fxi, kJ / kg,

where fxi is the specific chemical exergy, kJ / kg;

MI - the mass content of the components.

Physical exergi of iron can be calculated by the formula

Och

about

00

four

about

Yu

Ef CiS (Tpl - That) + q +

+ STplO 1-TPL) -To (St

fn

Jn that

+ JL 4-Gt1 -t- - I-ТТпл

I PA

fn

Ti

Tpl

), kJ / kg,

where Hu is the average heat capacity of cast iron in the range from To to Tpl, kdxc / kg-deg;

Stpl t ° in the range from Tpl to Ti, kJ / kggrad,

T0 - 298 K;

Tpl - melting point of cast iron, K;

TI is the temperature of the cast iron at the outlet, K;

q is the heat of fusion of cast iron, kJ / kg.

Changes in chemical and physical energies caused by variations in the silicon content of the iron and its temperature are determined respectively by the formulas

AEh-O.OG fxsi (1)

AEF STPL AT + To fn Al) (2)

where A Si and AT are the deviations of the silicon content in the iron and its temperature, respectively,

The total change of these values

A E A Ex + A Ef (3)

By the magnitude of AE, the change in the thermal state of the hearth is estimated and control actions are carried out.

Since the values of the iron temperature and the silicon content in it are interrelated, the values of A Ex and Déf should also be in a corresponding relationship. Violation of this dependence, i.e., the output of the AEx / AEf ratio from a certain range of values, indicates any malfunctions, for example, in a system for measuring and transmitting a signal on the temperature of the pig iron on release. In this case, control is not performed until the reasons for the violation of the specified ratio have been determined.

The quantitative limits are chosen for the following reasons.

The value of the permissible ratio of the optics of chemical and physical exergies is chosen based on the fact that

changing the silicon content in the iron by 0.1%, the temperature changes in the same direction by 5-12 ° C. Substituting these values in formula (1) allows

get the ratio AEx / A Ef 2-5.

The limitation of the lower limit of the total exergy deviation to 50 mJ / t of pig iron is due to the fact that this value corresponds to a change in the silicon content in the iron by 0.15-0.20% and the temperature of the iron by 15-20 ° C. The error in measuring the temperature of the iron is in the order of 1%, i.e. about 15 ° C. Therefore, with smaller deviations of the thermal regime, its stabilization has no practical meaning.

The implementation of the proposed method improves the accuracy and reliability of the assessment and

regulation of the thermal regime of blast-furnace smelting, which makes it possible to reduce the average content of silicon, sulfur and manganese in limit cast iron by 0.08; 0.002 and 0.04 abs.%, Respectively, the standard deviations of the content of silicon, sulfur and manganese in the iron decrease, respectively. by 0.05; 0.002 and 0.2 abs.%,

Claims (2)

1. A method for controlling the thermal regime of a blast furnace smelting, including the determination of the silicon content in the iron, its temperature measurement and the effect for fuel consumption, temperature and humidity to blow, characterized in that, in order to save coke, for fuel consumption. temperature and humidity blow affect the magnitude of the deviation of the chemical and physical exergy of cast iron from the given values. 2. A method according to claim 1, characterized in that the control actions are carried out if the sign of the deviations of both exergies is the same, and the deviation of chemical exergy is 2-5 from the deviation of physical exergy when their total deviation is more than 50 mJ / t cast iron.