Blast furnace distribution method

Abstract

The invention discloses a blast furnace charging method, which belongs to the technical field of blast furnace smelting. The charging method comprises: in a smelting cycle before the blast furnace is shut down for maintenance, the coke load and the center coke ratio of the blast furnace are gradually reduced in cycles; in b smelting cycles before the blast furnace is shut down for maintenance, all the combined coke added to the shut-down material is cancelled and the center coke is evenly distributed in other positions; in c smelting cycles before the blast furnace is shut down for maintenance, all the coke charging is cancelled and the center coke is evenly distributed in other positions; wherein, c<b<a. The charging method can make the blast furnace directly replace the airtight box at the top of the furnace after the wind is stopped, without the need to distribute the ore material on the material surface in the center area of ​​the top of the furnace to control the top temperature, thus reducing the maintenance time and facilitating the stable distribution and rapid recovery of the coal gas after the subsequent blast furnace is supplied with air.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace smelting, and in particular to a blast furnace charging method. Background Art

[0002] Center coking is a commonly used charging adjustment method in blast furnace production. By adding an appropriate amount of coke to the center of the blast furnace, the ore-coke ratio in the central area is reduced to form an inverted V-shaped soft melting zone to promote the smooth operation of the blast furnace and improve the activity of the furnace hearth.

[0003] During the production process, a certain amount of coke is added to the center area to form a narrow and strong central gas flow, which keeps the temperature in the center area of ​​the furnace top at a high level. After the blast furnace is ignited, a large amount of coke continues to burn on the furnace top material surface due to the formation of a through central coke column in the height direction of the center area. The temperature in the center area of ​​the furnace throat is still greater than 300°C, and the airtight box cannot be directly replaced on the furnace top during maintenance. In order to smoothly replace the airtight box, it is often necessary to place ore on the coke pile in the center area of ​​the furnace top to control the furnace top temperature.

[0004] Although the above method can effectively control the top temperature, directly placing ore in the center area of ​​the furnace top will not only prolong the maintenance time, but also destroy the gas distribution, and is not conducive to the recovery of the blast furnace after air supply. Summary of the invention

[0005] In view of the above problems, the present invention is proposed to provide a blast furnace charging method that overcomes the above problems or at least partially solves the above problems. By controlling the coke load, center coke ratio and center coke distribution in multiple smelting cycles before the blast furnace is stopped, the blast furnace can directly replace the furnace top airtight box after the blast furnace is stopped, without the need to distribute ore to the material surface in the center area of ​​the furnace top to control the furnace top temperature, which reduces the maintenance time and is conducive to laying a good foundation for the stable distribution and rapid recovery of coal gas after subsequent blast furnace air supply.

[0006] The present invention provides a blast furnace charging method, the charging method comprising:

[0007] In a smelting cycle before the blast furnace is shut down for maintenance, the coke load and central coke ratio of the blast furnace are gradually reduced in cycles;

[0008] In the b smelting cycles before the blast furnace is shut down for maintenance, all the combined coke added to the shut-down material is cancelled and distributed as center coke, and the cancelled center coke is evenly distributed in other stations;

[0009] In the c smelting cycles before the blast furnace is shut down for maintenance, all coke distribution is cancelled and the center coke is evenly distributed in other stations;

[0010] Among them, c<b<a.

[0011] Optionally, 1<a≤5, b=1, 1 / 5≤c≤1 / 4.

[0012] Optionally, within a smelting cycle before the blast furnace is shut down for maintenance, the coke load and central coke ratio of the blast furnace are gradually reduced in stages, including:

[0013] In 4 to 5 smelting cycles before the blast furnace is shut down for maintenance, the coke load is reduced by a first amplitude, the coke load is reduced from a reference load to a first load, and the coke quantity at the secondary center coke station is reduced by a first proportion;

[0014] During 1.2 to 3 smelting cycles before the blast furnace is shut down for maintenance, the coke load and the center coke ratio are reduced in two stages.

[0015] Optionally, the first amplitude is 12-15%, and the first ratio is 50%.

[0016] Optionally, the coke load and the central coke ratio are reduced in two stages within 1.2 to 3 smelting cycles before the blast furnace is shut down for maintenance, including:

[0017] In the three smelting cycles before the blast furnace is shut down for maintenance, the coke load is reduced by a second amplitude, the coke load is reduced from the reference load to the second load, and the central coke quantity is reduced by a second proportion;

[0018] Within 1.2 to 1.5 smelting cycles before the blast furnace is shut down for maintenance, the coke load is further reduced by the second amplitude, the coke load is reduced from the second load to the third load, and the central coke quantity is further reduced by the second proportion.

[0019] Optionally, the second amplitude is 15-20%, and the second ratio is 15-20%.

[0020] Optionally, the benchmark load is 5.50.

[0021] Optionally, reducing the focal amount of the secondary center focal station by a first ratio includes:

[0022] Reduce the loading of the secondary center focus 21° position by 1 circle to reduce the coke amount at the secondary center focus position by the first proportion.

[0023] Optionally, the material distribution method further includes:

[0024] Obtain the temperature of the center area of ​​the throat of the blast furnace after the air is stopped;

[0025] When the temperature of the center area of ​​the furnace throat is lower than the set temperature, the airtight box is replaced.

[0026] Optionally, the set temperature is 135°C.

[0027] The technical solution provided in the embodiments of the present invention has at least the following technical effects or advantages:

[0028] A blast furnace charging method provided by an embodiment of the present invention can quickly transform the material surface morphology from a "platform + steamed bun-shaped coke pile" type to a "platform + funnel" type before the blast furnace is stopped by controlling the coke load, central coke ratio and central coke distribution in multiple smelting cycles before the blast furnace is stopped. This allows the blast furnace to directly replace the furnace top airtight box after the blast furnace is stopped, without the need to distribute ore to the material surface in the central area of ​​the furnace top to control the furnace top temperature, thereby reducing maintenance time and being conducive to laying a good foundation for the stable distribution and rapid recovery of coal gas after subsequent blast furnace air supply.

[0029] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not considered to be limitations of the present invention. In addition, the same reference symbols are used to represent the same components throughout the accompanying drawings.

[0031] In the attached picture:

[0032] Figure 1 The present invention is a flowchart of a blast furnace charging method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0034] Figure 1 is a flow chart of a blast furnace charging method provided by an embodiment of the present invention, such as Figure 1 As shown, the cloth method includes:

[0035] Step S101, within a smelting cycle before the blast furnace is shut down for maintenance, the coke load and central coke ratio of the blast furnace are gradually reduced in cycles.

[0036] In this embodiment, 1<a≤5. Optionally, step S101 includes:

[0037] The first step is to reduce the coke load by a first magnitude within 4 to 5 smelting cycles before the blast furnace is shut down for maintenance, from the reference load to the first load, and reduce the coke quantity at the secondary center coke station by a first proportion;

[0038] In one implementation of this embodiment, the first amplitude is 12-15%, and the first ratio is 50%. That is, in the 4-5 smelting cycles before the blast furnace is shut down for maintenance, the coke load is reduced by 12-15%, and the coke quantity at the secondary center coke station is reduced by 50%. It should be noted that the first amplitude and the first ratio need to be matched and adjusted at the same time to promote the formation of the center funnel of the material surface.

[0039] In this embodiment, the focal amount at the sub-center focal position can be reduced by a first proportion by reducing the loading of the sub-center focal position by 21° for one circle.

[0040] The second step is to reduce the coke load and center coke ratio in two stages within 1.2 to 3 smelting cycles before the blast furnace is shut down for maintenance.

[0041] In order to ensure stable gas distribution during the adjustment process, different loads need to be reasonably matched with the central coke amount, so the coke load and central coke ratio are reduced in two stages.

[0042] Optionally, the second step specifically includes:

[0043] In the three smelting cycles before the blast furnace is shut down for maintenance, the coke load is reduced by a second amplitude, the coke load is reduced from the reference load to the second load, and the central coke quantity is reduced by a second proportion;

[0044] During 1.2 to 1.5 smelting cycles before the blast furnace is shut down for maintenance, the coke load is further reduced by a second amplitude, the coke load is reduced from the second load to the third load, and the central coke quantity is further reduced by a second proportion.

[0045] In one implementation of this embodiment, the second amplitude is 15-20%, and the second ratio is 15-20%. That is, within the three smelting cycles before the blast furnace is shut down for maintenance, the coke load is reduced by 15-20%, and the central coke quantity is reduced by 15-20%. Then, within the 1.2-1.5 smelting cycles before the blast furnace is shut down for maintenance, the coke load is further reduced by 15-20%, and the central coke quantity is further reduced by 15-20%. It should be noted that the second amplitude and the second ratio need to be matched and adjusted at the same time to promote the formation of the central funnel of the material surface.

[0046] For example, the baseline load is 5.50. Within 4-5 smelting cycles before the wind stop, the coke load decreases from 5.50 to 4.81; within 3 smelting cycles before the wind stop, the coke load decreases from 5.50 to 4.50; within 1.2 to 1.5 smelting cycles before the wind stop, the coke load decreases from 4.50 to 3.50.

[0047] Step S102: within b smelting cycles before the blast furnace is shut down for maintenance, all the combined coke added to the shut-down material is cancelled and distributed as center coke, and the cancelled center coke is evenly distributed in other stations.

[0048] In this embodiment, b=1. That is, in the b smelting cycles before the blast furnace is shut down for maintenance, all the combined coke added to the shut-down material is cancelled and the central coke is evenly distributed in other positions. It should be noted that the cancelled central coke in this embodiment needs to be evenly distributed in other positions except the highest position.

[0049] Step S103: In the c smelting cycles before the blast furnace is shut down for maintenance, all coke distribution except for the center coke is cancelled, and the cancelled center coke is evenly distributed in other stations.

[0050] Among them, c<b<a. In this embodiment, 1 / 5≤c≤1 / 4. That is, in the 1 / 5 to 1 / 4 smelting cycle before the blast furnace is shut down for maintenance, all coke distribution is cancelled except for the center coke, and the cancelled center coke is evenly distributed in other stations. It should be noted that the cancelled center coke in this embodiment needs to be evenly distributed in other stations except the highest position.

[0051] Optionally, the cloth method further includes:

[0052] Obtain the temperature of the center area of ​​the throat of the blast furnace after the air is stopped;

[0053] When the temperature in the center area of ​​the furnace throat is lower than the set temperature, replace the airtight box.

[0054] Due to the bun-shaped coke pile material surface, the temperature in the center area of ​​the furnace throat is often greater than 300°C. Therefore, in one implementation of this embodiment, the set temperature can be 135° to ensure that the material surface shape becomes funnel-shaped.

[0055] It should be noted that the above-mentioned material distribution method must be carried out on the basis of continuous and stable operation of the blast furnace.

[0056] In order to enable those skilled in the art to have a deeper understanding of the technical solution of the present application, a complete embodiment will be described below.

[0057] For example, during normal production and smelting of the blast furnace, the ore batch is 180 tons and the basic load is 5.50; central coking is adopted for smelting, with 6 turns of central coke (accounting for 24%) and a gas utilization rate of 50.1%; the coke ratio is 279kg / t and the fuel ratio is 492kg / t; molten iron [SI]: 0.35, the molten iron temperature is above 1500℃, and the slag basicity is 1.21.

[0058] The adjustment of the blast furnace air stop material system using the material distribution method of the present application is shown in Table 1 below:

[0059] Table 1

[0060]

[0061] The specific steps are as follows:

[0062] Step 1: During the 4.5 smelting cycles before the blast furnace is shut down for maintenance, the coke load is reduced from 5.50 to 4.81, with a reduction of 12.5% ​​in the coke load, and the secondary center coke is reduced by 210 positions for one circle to promote the formation of a center funnel on the material surface;

[0063] Step 2: In the three smelting cycles before the blast furnace is shut down for maintenance, the coke load is reduced from 5.50 to 4.50, the coke load reduction is 18.2%, and the central coke volume is reduced by 16.7%;

[0064] Step 3: During the 1.2-1.5 smelting cycles before the blast furnace is shut down for maintenance, the coke load is reduced from 4.50 to 3.50, the decoking load is reduced by 18.2%, and the central coke amount is reduced by 16.7%;

[0065] Step 4: In one smelting cycle before the blast furnace is shut down for maintenance, all the combined coke (4+2+2+1) added to the shut-down material is cancelled and the center coke is evenly distributed at other positions (except the maximum angle) (as shown in Table 3);

[0066] Step 5: For the last 8 batches of normal materials (8 batches account for 1 / 4.2 of the smelting cycle of the whole furnace material) with air-stopping, all the central coke shall be eliminated and the eliminated central coke shall be evenly distributed at other positions (except the maximum angle) (as shown in Table 4).

[0067] Step 6: During the operation of steps 1-5, the furnace condition is stable, and the full wind and furnace temperature are sufficient. After the wind is stopped, the material surface shape has changed from "platform + steamed bun-shaped coke pile" to "platform + funnel". After the wind is stopped, the temperature in the center area of ​​the furnace throat is less than 135℃. There is no need to control the top temperature of the center coke pile by ore distribution and fire suppression, and the airtight box can be replaced directly.

[0068] The embodiments of the present invention provide a table of various station angles under the normal coke charging system (see Table 2 below), a table of various station angles under the additional coke charging system (see Table 3 below), and a table of coke charging system for the last 1 / 4-1 / 5 of the smelting cycle (see Table 4 below).

[0069] Table 2

[0070] angle <![CDATA[44.5 0 ]]> <![CDATA[42.5 0 ]]> <![CDATA[40.5 0 ]]> <![CDATA[38.5 0 ]]> <![CDATA[36 0 ]]> <![CDATA[33 0 ]]> <![CDATA[27 0 ]]> <![CDATA[21 0 ]]> <![CDATA[9 0 ]]> C 4 3 2 2 2 2 2 2 6

[0071] Table 3

[0072] angle <![CDATA[44.5 0 ]]> <![CDATA[42.5 0 ]]> <![CDATA[40.5 0 ]]> <![CDATA[38.5 0 ]]> <![CDATA[36 0 ]]> <![CDATA[33 0 ]]> <![CDATA[27 0 ]]> <![CDATA[21 0 ]]> C 4 3 3 3 3 3 3 2

[0073] Table 4

[0074] angle <![CDATA[44.5 0 ]]> <![CDATA[42.5 0 ]]> <![CDATA[40.5 0 ]]> <![CDATA[38.5 0 ]]> <![CDATA[36 0 ]]> <![CDATA[33 0 ]]> <![CDATA[27 0 ]]> <![CDATA[21 0 ]]> C 4 3 3 3 3 3 3 2

[0075] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0076] A blast furnace charging method provided by an embodiment of the present invention can quickly transform the material surface morphology from a "platform + steamed bun-shaped coke pile" type to a "platform + funnel" type before the blast furnace is stopped by controlling the coke load, central coke ratio and central coke distribution in multiple smelting cycles before the blast furnace is stopped. This allows the blast furnace to directly replace the furnace top airtight box after the blast furnace is stopped, without the need to distribute ore to the material surface in the central area of ​​the furnace top to control the furnace top temperature, thereby reducing maintenance time and being conducive to laying a good foundation for the stable distribution and rapid recovery of coal gas after subsequent blast furnace air supply.

[0077] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0078] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the intention that the claimed invention requires more features than those explicitly recited in each claim. More specifically, as reflected in the claims below, inventive aspects lie in less than all the features of the individual embodiments disclosed above. Therefore, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, with each claim itself serving as a separate embodiment of the present invention.

[0079] It should be noted that the above embodiments illustrate the present invention rather than limit it, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets shall not be construed as a limitation on the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "one" or "an" preceding a component does not exclude the presence of a plurality of such components. The present invention may be implemented by means of hardware comprising a number of different components and by means of a suitably programmed computer. In a unit claim enumerating a number of devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc., does not indicate any order. These words may be interpreted as names.

Claims

1. A method for distributing material to a blast furnace, characterized in that: The cloth dispensing method comprises: In a smelting cycle before the blast furnace is shut down for maintenance, the coke load and central coke ratio of the blast furnace are gradually reduced in cycles; In the b smelting cycles before the blast furnace is shut down for maintenance, all the combined coke added to the shut-down material is cancelled and distributed as center coke, and the cancelled center coke is evenly distributed in other stations; In the c smelting cycles before the blast furnace is shut down for maintenance, all coke distribution is cancelled and the center coke is evenly distributed in other stations; Among them, 1<a≤5, b=1, 1 / 5≤c≤1 / 4; The step of gradually reducing the coke load and central coke ratio of the blast furnace in a smelting cycle before the blast furnace is shut down for maintenance includes: In 4 to 5 smelting cycles before the blast furnace is shut down for maintenance, the coke load is reduced by a first amplitude, the coke load is reduced from a reference load to a first load, and the coke quantity at the secondary center coke station is reduced by a first proportion; In the three smelting cycles before the blast furnace is shut down for maintenance, the coke load is reduced by a second amplitude, the coke load is reduced from the reference load to the second load, and the central coke quantity is reduced by a second proportion; Within 1.2 to 1.5 smelting cycles before the blast furnace is shut down for maintenance, the coke load is further reduced by the second amplitude, the coke load is reduced from the second load to the third load, and the central coke quantity is further reduced by the second proportion.

2. The material distributing method according to claim 1, characterized in that: The first amplitude is 12-15%, and the first ratio is 50%.

3. The material distributing method according to claim 1, characterized in that: The second amplitude is 15-20%, and the second ratio is 15-20%.

4. The material distributing method according to claim 1, characterized in that: The reference load is 5.

50.

5. The material distributing method according to claim 1, characterized in that: The step of reducing the focal amount of the secondary central focal station by a first ratio comprises: Reduce the loading of the secondary center focus 21° position by 1 circle to reduce the coke amount at the secondary center focus position by the first proportion.

6. The material distributing method according to claim 1, characterized in that: The cloth dispensing method further comprises: Obtain the temperature of the center area of ​​the throat of the blast furnace after the air is stopped; When the temperature of the center area of ​​the furnace throat is lower than the set temperature, the airtight box is replaced.

7. The material distributing method according to claim 6, characterized in that: The set temperature is 135°C.

Images