RU2254374C1 - Method of a blast-furnace smelt - Google Patents

Abstract

FIELD: metallurgy; blast-furnace production.

SUBSTANCE: the invention is pertaining to the field of metallurgy, in particular, to the blast-furnace production. The method of a blast-furnace smelt includes loading of ore and fuel components realized in a mixed or separate way in a furnace-charging carriage or various furnace-charging carriages in one or several skips within the limits of one or several feeds, an air-blast supply and tapping. At that the ore and fuel components are delivered from the hopper weighers into the furnace-charging skips ensuring the following ratio: P : v_o = K : v_f, where P - a number of the ore components in a hopper weigher, t(tons); K - a number of fuel components in a hopper weigher, t(tons); v_o and v_f - rate of delivery accordingly of the ore and the fuel (coke) components from the hopper weighers into a skip, t/s (tons/seconds). At that per each 10 % of the materials loaded in a mixed state intensity of the blast boost is increasing by 0.1 - 0.5 %. The purpose of the invention is to increase productivity of a blast furnace and to decrease specific consumption of coke.

EFFECT: the invention ensures increased productivity of a blast furnace and decreased specific consumption of coke.

2 tbl

Description

The invention relates to ferrous metallurgy, in particular to blast furnace production, and can be used in the smelting of pig iron in blast furnaces.

A technical solution is known, according to which for loading ore and fuel components in a mixed state, alternately ore and fuel components are loaded into each skip in portions of 0.5 volumes of skip (Steel, 1977, No. 5, S.391-394).

The disadvantages of this method are the limited productivity of the blast furnace due to the increase in the time of recruitment of the charge components and the low quality of mixing ore and fuel components at the loading site.

Closest to the claimed method in terms of properties and achieved results is a blast furnace smelting method, comprising loading ore and fuel components in a mixed state into one skip or various skips within one or in different feeds, blowing and releasing melting products, with ore and fuel components load portions from 0.05 to 0.5 skip volumes (AS USSR No. 749897, MKI C 21 V 7/20).

The disadvantages of this method are the low skip loading speed, poor-quality mixing of ore and fuel components, the absence of a rate of change in intensity along the blast. This limits the increase in productivity of the blast furnace and the decrease in specific consumption of coke.

The present invention solves the problem of increasing the productivity of the blast furnace and reducing the specific consumption of coke.

This is achieved by the fact that in the blast furnace smelting process, comprising loading the ore and fuel components in a mixed state into one skip or various skips within the same or different feeds, blowing and releasing melting products, when loading materials, ore and fuel components are extracted from weight funnel in the skip, providing the ratio:

P: υ _p = K: υ _k ,

where P is the number of ore components in the weight funnel, t;

K is the number of fuel components in the weight funnel, t;

υ _p and υ _k - the rate of delivery of ore and fuel components, respectively, from weight funnels to the skip, t / s,

moreover, for every 10% of materials loaded in a mixed state, the intensity of the blast is increased by 0.1-0.5%.

The proposed method will allow you to accumulate the mixture in the skip with high speed and at the same time improve the mixing of ore components with fuel, which is explained by the receipt in the skip of ore and fuel components with agreed speeds for the same period of time. Improving mixing, increasing the intensity of the blast, increasing the productivity of the loading area lead to an increase in the productivity of the blast furnace in terms of the amount of cast iron and to a decrease in the specific consumption of coke.

The method is as follows.

The weight of ore (P) and fuel (K) components in their weight funnels is determined from the given values of ore and fuel spikes and the number of skips of each of these materials in the feed. Set the rate of delivery of ore components from the weight funnel to the skip (υ _р ). The rate of delivery of the fuel components from the weight funnel to the skip (υ _k ) is determined by the formula:

P: υ _p = K: υ _k ,

from which it follows:

υ _к = К · υ _р / Р.

Set the loading mode of ore and fuel components in a mixed state and conduct blast furnace smelting with an increase in intensity by blasting by 0.1-0.5% for every 10% of materials loaded in a mixed state.

In the expression P: υ _p = K: υ _k , the ratio P: υ _p shows the duration of the set of ore components from the weight funnel to the skip, and K: υ _k - the duration of the set of fuel components from the weight funnel to the skip. Therefore, equality of relations means equality of the duration of the set of ore and fuel components. The simultaneous receipt of materials from two weight funnels - with a given speed of ore components and an agreed fuel speed - provides quick skip filling, which, in turn, provides the necessary performance of the loading section. The speed of delivery of the constituents of the charge into the blast furnace top space ceases to restrain its productivity growth by the number of melted materials and, accordingly, the obtained melting products. This is important in modern conditions, since on large well-functioning blast furnaces, the productivity of the loading section often limits the further increase in pig iron production.

The receipt of ore and fuel components from different weight funnels into the skip with coordinated speeds improves the quality of mixing them compared to a different set, which contributes to a better use of gas energy and, accordingly, saving specific coke consumption.

An increase in the blast intensity by 0.1-0.5% for every 10% of materials loaded in a mixed state increases the amount of gases processing the charge by the same amount, which, on the one hand, increases the productivity of the furnace, and, on the other, additionally loosens the charge , helps to reduce the specific consumption of coke.

The increase in the intensity of the blast by less than 0.1% for every 10% of the materials loaded in the mixed state, leads to the formation of a small amount of gases generated in the furnace, which leads to lower productivity of the furnace compared to the claimed method. The increase in the intensity of the blast by more than 0.5% for every 10% of the materials loaded in a mixed state leads to a violation of the evenness of the charge in the furnace, which leads to a decrease in the productivity of cast iron and a specific consumption of coke increases compared to the claimed method.

The proposed method was tested on a blast furnace of OJSC MMK with a volume of 1370 m ³ .

The set ore spike was 28 tons, the fuel one represented by coke was 7.4 tons. The number of ore skips in the feed was 2, and coke skips were 2. The set rate for the ore components from the weight funnel to the skip was υ _р = 0.87 t / s.

The weight of the ore components in the weight funnel was:

P = 28: 2 = 14 t

fuel component represented by coke:

K = 7.4: 2 = 3.8 t.

The rate of delivery of the fuel component (coke) from the weight funnel to the skip was:

υ _к = 3.8 · 0.87 / 14 = 0.24 t / s.

The duration of the set of ore and fuel components in the skip according to the claimed method was:

14 / 0.87 = 3.8 / 0.24 = 16 s.

The loading of ore and fuel components according to the prototype and the claimed method was carried out cyclically. The cycle consisted of seven feeds, of which three feeds were loaded with a mixture of ore and fuel components, and four with a separate set of them in skips. Each feed in mixed and separate states included four skips of the charge components. In a mixed state, ore and coke parts of the charge were collected in each skip; in separate condition, the first two skips were represented by the ore part, and the next two skips were represented by coke. The contents of each skip were loaded onto a small cone, then loaded onto a large one. After the next feed was set on a large cone, lowering it loaded the component charges into the furnace top space.

Thus, the proportion of materials loaded in a mixed state was:

3 · 100 / (3 + 4) = 43%,

where 3 is the number of feeds with a mixture of ore and fuel components;

4 - the number of feeds with a separate set of ore and fuel components.

The intensity of the blast increased by:

43/10 · 0.3 = 1.3%,

where 0.3 is the average value of the increase in intensity by blast for every 10% of materials loaded in a mixed state - (0.1 + 0.5) / 2 = 0.3%.

The duration of the furnace according to the prototype and using the proposed technical solution was ten days. The results obtained are presented in table 1. The blast furnace performance at various increases in blast intensity are presented in table 2.

Table 1 The performance of the blast furnace in the conduct of blast furnace melting known and proposed method The name of indicators Prototype The proposed method Productivity, t / day 3384 3465 Specific consumption of coke, kg / t of pig iron 436.7 429.4 The composition of the ore part of the charge,%: - agglomerate 59.8 60.3 - pellets 40,2 39.7 The consumption of the components of the ore part of the charge, kg / t of pig iron: - agglomerate 990 992 - pellets 665 666 Dust removal (captured), kg / t of pig iron 39.5 41.8 Blast Parameters: - intensity, m ³ / min 3093 3133 - pressure, atm. 3.75 3.76 - temperature, ° С 1162 1158 - humidity, g / m ³ 10.9 12.1 - natural gas consumption, m ³ / t of pig iron 100 98 - oxygen content,% 26.1 26.1 Top gas parameters: - pressure, atm. 2.45 2.45 - temperature, ° С 386 380 Composition, %: - СО ₂ 19.9 20.1 - WITH 23,4 23,2 - H ₂ 8.0 7.9 Cast iron composition,%: -Si 0.61 0.62 -Mn 0.22 0.21 -S 0.017 0.016 -R 0,055 0,054

The name of indicators Prototype The proposed method -FROM 4,54 4,5 -Ti 0,079 0,083 Slag composition,%: -SiO ₂ 36.5 36.7 - Al ₂ O ₃ 12.3 12,2 -CAO 39.6 39.5 -MgO 7.6 7.5 -MnO 0.19 0.2 -FeO 0.2 0.21 -S 0.89 0.91 TiO ₂ 0.93 0.95

table 2 Blast furnace performance at various increases in blast intensity The increase in the intensity of the blast for every 10% of the materials loaded in the mixed state,% Indicators 0 (prototype) 0.05 0.09 0.3 (the proposed method) 0.51 0.6 Coke consumption, kg / t pig iron 436.7 435.1 433.9 429.4 436.2 442.5 Productivity, t / day 3384 3430 3435 3465 3392 3351

The data in the tables indicate that when conducting blast furnace smelting by the proposed method, the furnace productivity increased by 2.4% compared with the known method, and the specific coke consumption decreased by 3.3 kg / t of pig iron.

Claims (1)

A blast furnace smelting method, comprising loading the ore and fuel components in a mixed and separate state into one skip or different skips within the same or different feeds, blowing and releasing melting products, characterized in that when loading materials the ore and fuel components give out simultaneously from weight funnels to skip, providing a ratio P: υ _p = K: υ _k where P is the number of ore components in the weight funnel, t; K is the number of fuel components in the weight funnel, t; υ _p and υ _k - the rate of delivery of ore and fuel components from weight funnels to the skip, t / s, respectively moreover, for every 10% of the loaded materials, the intensity of the blast is increased by 0.1 - 0.5%.