Method for rapidly reducing blast furnace temperature

Abstract

The invention relates to the technical field of blast furnace smelting, and provides a method for rapidly reducing the blast furnace temperature of a blast furnace, which comprises the following steps: S1, determining a reference fuel ratio FR reference; s2, the average fuel ratio # imgabs0 # in continuous n hours before the blast furnace temperature appears is calculated, wherein n is larger than or equal to 4 and smaller than or equal to 6; s3, comparing the FR standard and # imgabs1 # to calculate that the excessive fuel ratio FR in n hours is more than the total quantity FR; and S4, within 1-2 hours, the excessive fuel is subtracted from the total amount FR by reducing the coal injection amount. According to the method, the fuel ratio is reduced by intensively and greatly reducing the coal injection amount, and the furnace temperature can be reduced to a normal range within n + 2 hours, so that the furnace temperature reducing time is greatly shortened, the loss of the production technical indexes of the blast furnace is reduced, and the influence of too high or too low furnace temperature on the smooth operation of the blast furnace is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of blast furnace smelting, and in particular to a method for rapidly reducing the temperature of a blast furnace. Background Art

[0002] Generally, there are two ways to express blast furnace temperature. The first is to express it as the physical heat of molten iron, with the unit being ℃, and the second is to express it as the mass fraction of Si element in the molten iron, with the unit being %. In the present invention, the second expression is taken as the standard. All large blast furnaces are required to control the furnace temperature within the range of 0.25%-0.55%. A temperature above 0.70% is considered to be a high furnace temperature.

[0003] During the process of lowering the furnace temperature, blast furnace operators often reduce the coal amount in multiple steps. This is a relatively conservative approach. Due to the large thermal inertia of large blast furnaces, this approach can even cause the furnace temperature to "rise higher as it falls." This high furnace temperature persists for a long time, resulting in significant losses in blast furnace output and technical indicators. It is also prone to overhanging materials or pipe travel, posing a significant threat to the stable and smooth operation of the blast furnace. Furthermore, after multiple reductions in the coal amount and fuel ratio, the furnace temperature is prone to low levels after the minimum fuel ratio is reached. Excessively low furnace temperatures can lead to serious accidents such as material slippage, collapse, and even furnace cooling, causing huge losses to the company. At this point, the blast furnace operator is faced with the dilemma of having to raise the furnace temperature. This approach results in a "roller coaster"-like fluctuation in furnace temperature, first high, then low, and then raising it again, which is detrimental to the stable and smooth operation of the blast furnace and cost reduction.

[0004] Prior art CN108060281B discloses a method for reducing the temperature of a blast furnace, comprising the following steps in sequence: 1. reducing the furnace temperature; 2. controlling the furnace temperature; 3. determining the fuel ratio, thereby reducing ironmaking fuel consumption and reducing ironmaking costs.

[0005] The prior art CN108060281B has the disadvantage of a long duration of furnace temperature reduction. Combining with its embodiments, it can be seen that the duration of furnace temperature reduction is as long as 8-16 hours or even longer. Long-term high furnace temperature will inevitably have a negative impact on the stable and smooth operation of the blast furnace, such as causing pipeline travel, suspended materials, etc., threatening the stable and smooth operation of the blast furnace. Summary of the Invention

[0006] The purpose of the embodiment of the present invention is to provide a method for quickly reducing the temperature of a blast furnace, significantly shortening the temperature reduction time, reducing the loss of blast furnace production technical indicators, and avoiding the impact of excessively high or low furnace temperature on the smooth operation of the blast furnace.

[0007] The embodiment of the present invention provides a method for quickly reducing the temperature of a blast furnace, which adopts the following technical solutions:

[0008] A method for rapidly reducing the temperature of a blast furnace comprises the following steps:

[0009] S1. Determine the reference fuel ratio FR 基准 ;

[0010] S2. Calculate the average fuel ratio for n consecutive hours before the high furnace temperature appears. Where 4≤n≤6;

[0011] S3, compared with FR 基准 and Calculate the total excess fuel ratio FR within n hours 多出 ;

[0012] S4, within 1 to 2 hours, by reducing the amount of coal injection, the excess fuel is reduced to the total amount FR 多出 minus.

[0013] Preferably, in S1, the reference fuel ratio FR 基准 Determine by the following method: select the average value of the mass fraction of Si element in molten iron for any continuous n hours in actual production, and calculate the average fuel ratio that determines the furnace temperature for any continuous n hours as the reference fuel ratio FR 基准 .

[0014] Preferably, compare the average furnace temperature of any continuous n hours with the furnace temperature required for production. If the deviation between the two is more than ±0.1%, the FR 基准 Make corrections and re-determine FR 基准 .

[0015] Preferably, FR 基准 Correction is made by the following method: every 0.1% increase in furnace temperature corresponds to an increase of 5Kg / tFe, and every 0.1% decrease in furnace temperature corresponds to a decrease of 5Kg / tFe.

[0016] Preferably, in S2, in,

[0017] FR -n is the fuel ratio n hours before the high furnace temperature appears;

[0018] FR -n+1 is the fuel ratio in the n-1 hour before the high furnace temperature appears;

[0019] FR -n+2 is the fuel ratio in the n-2 hours before the high furnace temperature appears;

[0020] FR -1 It is the fuel ratio in the first hour before high furnace temperature appears.

[0021] Preferably, in S3, the excess fuel is

[0022] Preferably, in S4, the excess fuel in the first n hours is converted to the total amount FR 多出 Subtract once, and make the average fuel ratio for n+1 hours before the high furnace temperature appears With FR 基准 Equal or similar, the first n+2 hours are based on FR 基准 Production;

[0023] Among them, FR0 is the fuel ratio in the hour when high furnace temperature occurs.

[0024] Preferably, in S4, the total amount of fuel ratio FR is deducted from the n+1 hour and the n+2 hour. 多出 , so that the average fuel ratio in the first n+2 hours is With FR 基准 Equal or similar, the first n+3 hours are based on FR 基准 Production, Among them, FR1 is the fuel ratio in the first hour after the high furnace temperature appears.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention reduces the fuel ratio by significantly reducing the amount of coal injection, and can reduce the furnace temperature to a normal range within n+2 hours, thereby significantly shortening the furnace temperature reduction time, reducing the loss of blast furnace production technical indicators, and avoiding the impact of excessively high or low furnace temperature on the smooth operation of the blast furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 It is a flowchart of the present invention. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0031] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0032] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of this application is typically placed when in use. These terms are intended only to facilitate the description of this application and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] Furthermore, terms such as "horizontal," "vertical," and "overhanging" do not necessarily imply that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0034] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0035] The embodiment of the present invention provides a method for quickly reducing the temperature of a blast furnace, comprising the following steps:

[0036] S1. Determine the reference fuel ratio FR 基准 ;

[0037] S2. Calculate the average fuel ratio for n consecutive hours before the high furnace temperature appears. Where 4≤n≤6;

[0038] The formula for calculating the fuel ratio is: FR = [(M / n) + K] / P, where FR is the fuel ratio in tons;

[0039] M is the coal injection amount per hour, in tons;

[0040] n is the material rate per hour;

[0041] K is the coke batch size, in tons;

[0042] P is the theoretical iron production of each batch of charge; the unit is tons.

[0043] It can be seen from the calculation formula of the fuel ratio FR that when the blast furnace ore batch and dry coke batch remain unchanged, K and P are fixed values. Therefore, the blast furnace temperature depends on the coal injection amount M and the hourly material rate n. Since coal injection has a thermal lag of 4 hours, the current fuel ratio determines the furnace temperature 4 hours later, so the optimal value of n is 4.

[0044] S3, compared with FR 基准 and Calculate the total excess fuel ratio FR within n hours 多出 ;

[0045] S4, within 1 to 2 hours, by reducing the amount of coal injection, the excess fuel is reduced to the total amount FR 多出 minus.

[0046] Furthermore, in S1, the reference fuel ratio FR 基准 Determine by the following method: select the average value of the mass fraction of Si element in molten iron for any continuous n hours in actual production, and calculate the average fuel ratio that determines the furnace temperature for any continuous n hours as the reference fuel ratio FR 基准 .

[0047] Furthermore, if the average furnace temperature of any continuous n hours is compared with the furnace temperature required for production, if the deviation between the two is more than ±0.1%, the FR 基准 Make corrections and re-determine FR 基准 .

[0048] Furthermore, FR 基准 Correction can be made by the following method: every 0.1% increase in furnace temperature corresponds to an increase of 5Kg / tFe, and every 0.1% decrease in furnace temperature corresponds to a decrease of 5Kg / tFe. For example, if the fuel ratio is 520 for 4 consecutive hours, the average furnace temperature after the fuel ratio is issued is 0.55%, while the furnace temperature required by production is 0.45%, then the FR needs to be adjusted. 基准 Make corrections and re-determine FR 基准 , a 0.1% drop in furnace temperature requires a 5kg / tFe reduction in fuel ratio, so 515 is determined as the base fuel ratio.

[0049] Furthermore, in S2, in,

[0050] FR -n is the fuel ratio n hours before the high furnace temperature appears;

[0051] FR -n+1 is the fuel ratio in the n-1 hour before the high furnace temperature appears;

[0052] FR -n+2 is the fuel ratio in the n-2 hours before the high furnace temperature appears;

[0053] FR -1 It is the fuel ratio in the first hour before high furnace temperature appears.

[0054] Furthermore, in S3, the extra fuel is

[0055] Furthermore, in S4, the excess fuel in the first n hours is converted to the total amount FR in the n+1th hour. 多出 Subtract once, and make the average fuel ratio for n+1 hours before the high furnace temperature appears With FR 基准 Equal or similar, the first n+2 hours are based on FR 基准 Production;

[0056] Among them, FR0 is the fuel ratio in the hour when high furnace temperature occurs.

[0057] Furthermore, in S4, in order to avoid insufficient time for subtracting the fuel ratio or considering that subtracting too much fuel ratio in one hour may have other effects, the total amount of excess fuel ratio FR is subtracted in the n+1 hour and the n+2 hour. 多出 , so that the average fuel ratio in the first n+2 hours is With FR 基准 Equal or similar, then at hour n+3 according to FR 基准 Production, Among them, FR1 is the fuel ratio in the first hour after the high furnace temperature appears.

[0058] Example 1

[0059] On a certain day, the blast furnace was operating smoothly and the coke load was 126 / 23 = 5.48t / t. The coke load is the ratio of the ore batch weight to the dry coke batch weight. There were no other adjustments to the blast furnace. Check the recent blast furnace operation report. The recent operating benchmark fuel ratio FR 基准 513Kg / tFe, taking n=4 as an example, the day shift from 10:00 to 13:00 is 517.8Kg / tFe, at this time FR 基准 The total extra fuel ratio is 4*4.8=19.2Kg / tFe. This fuel ratio was issued around 14:00 during the day shift. After that, the furnace temperature rose sharply from 0.45% to 0.80%. In the fifth hour, that is, at 14:00 during the day shift, the coal volume was reduced to 65.7t / h, corresponding to a fuel ratio of 494Kg / tFe. The fuel ratio subtracted within 1 hour is: 513-494=19Kg / tFe. The fuel ratio subtracted within 1 hour is 19Kg / tFe, which is close to the extra fuel ratio of 19.2Kg / tFe. Therefore, With FR 基准 Similarly, after the subtracted fuel ratio was issued, the blast furnace temperature dropped to 0.42%. The processing time from the furnace temperature rising to the normal temperature recovery was 4 hours, and there was no loss in the blast furnace. The fuel ratio control during the process of lowering the furnace temperature is shown in Table 1:

[0060] Table 1: Fuel ratio control during high furnace temperature treatment on a certain day

[0061] time Material speed / piece / h Coal volume / t / h Fuel ratio / Kg / tFe Furnace temperature / % 10:00 5 70.0 520.7 0.56 11:00 5.5 70.9 506.4 0.5 12:00 5 70.7 522.4 0.45 13:00 5 70.4 521.9 0.65 14:00 5.5 65.7 494.0 0.80 15:00 5.5 70.9 506.3 0.73 16:00 5 68.2 516.1 0.6 17:00 6 67.7 482 0.58 18:00 5.5 72.0 505.6 0.42

[0062] Example 2

[0063] On another day, the furnace condition of a blast furnace was stable and smooth, and there was no significant adjustment to the blast furnace. The operating reference fuel ratio FR 基准 514Kg / tFe, taking n=4 as an example, the night shift from 5:00 to 8:00 is 522.3Kg / tFe, at this time FR 基准 The total extra fuel ratio is 4*8.3=33.2Kg / tFe. This fuel ratio was issued around 9:00 am during the day shift. After that, the furnace temperature rose sharply from 0.54% to 0.83%. In the 5th and 6th hours, that is, at 9:00 am and 10:00 am during the day shift, the coal injection rate was reduced to 63.1 t / h and 65.1 t / h respectively. The corresponding fuel ratios in the 5th and 6th hours were 503.4 Kg / tFe and 493.5 Kg / tFe respectively. The total fuel ratio subtracted in 2 hours is: 2*[514-(503.4+493.5) / 2]=31.1 Kg / tFe. The subtracted fuel ratio of 31.1 Kg / tFe is close to the extra fuel ratio of 33.2 Kg / tFe. 514.3Kg / tFe, With FR 基准 The difference is almost the same. After the subtracted fuel ratio is issued, the blast furnace temperature drops to 0.53%. The processing time from the furnace temperature rising to the normal temperature recovery is 4 hours. The blast furnace loses 0.5 batches of materials, which has no effect on the stable operation of the furnace condition. The fuel ratio control during the process of lowering the furnace temperature is shown in Table 2:

[0064] Table 2: Fuel ratio control during high furnace temperature treatment on another day

[0065] time Material speed / piece / h Coal volume / t / h Fuel ratio / Kg / tFe Furnace temperature / % 5:00 5 73.2 528.8 0.53 6:00 5.5 71.8 508.9 0.53 7:00 5 70.0 520.9 0.54 8:00 4.5 66.4 530.5 0.54 9:00 5 63.1 503.4 0.83 10:00 5.5 65.1 493.5 0.71 11:00 5.5 67.5 497.7 0.57 12:00 5.5 70.5 504.6 0.53 13:00 5.5 71.6 503.8 0.46

[0066] It can be seen that the method for quickly lowering the temperature of a blast furnace provided by the present invention can reduce the furnace temperature to a normal range within n+2 hours, greatly shortening the temperature reduction time, reducing the loss of blast furnace production technical indicators, and avoiding the impact of excessively high or low furnace temperature on the smooth operation of the blast furnace.

[0067] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for rapidly reducing the temperature of a blast furnace, characterized in that: The steps include: S1. Determine the reference fuel ratio FR 基准 ; S2. Calculate the average fuel ratio for n consecutive hours before the high furnace temperature appears. Where 4≤n≤6; S3, compared with FR 基准 and Calculate the total excess fuel ratio FR within n hours 多出 ; S4, within 1 to 2 hours, by reducing the amount of coal injection, the excess fuel is reduced to the total amount FR 多出 minus.

2. The method for rapidly reducing the temperature of a blast furnace according to claim 1, wherein: In S1, the reference fuel ratio FR 基准 Determine by the following method: select the average value of the mass fraction of Si element in molten iron for any continuous n hours in actual production, and calculate the average fuel ratio that determines the furnace temperature for any continuous n hours as the reference fuel ratio FR 基准 .

3. The method for rapidly reducing the temperature of a blast furnace according to claim 2, wherein: Compare the average furnace temperature for any continuous n hours with the furnace temperature required for production. If the deviation between the two is more than ±0.1%, the FR 基准 Make corrections and re-determine FR 基准 .

4. The method for rapidly reducing the temperature of a blast furnace according to claim 3, wherein: FR 基准 Correction is made by the following method: every 0.1% increase in furnace temperature corresponds to an increase of 5Kg / tFe, and every 0.1% decrease in furnace temperature corresponds to a decrease of 5Kg / tFe.

5. The method for rapidly reducing the temperature of a blast furnace according to claim 1, wherein: In S2, in, FR -n is the fuel ratio n hours before the high furnace temperature appears; FR -n+1 is the fuel ratio in the n-1 hour before the high furnace temperature appears; FR -n+2 is the fuel ratio in the n-2 hours before the high furnace temperature appears; FR -1 It is the fuel ratio in the first hour before high furnace temperature appears.

6. The method for rapidly reducing the temperature of a blast furnace according to claim 5, wherein: In S3, the extra fuel is greater than the total amount 7. The method for rapidly reducing the temperature of a blast furnace according to claim 6, wherein: In S4, in the n+1th hour, the excess fuel in the first n hours is converted to the total amount FR 多出 Subtract once, and make the average fuel ratio for n+1 hours before the high furnace temperature appears With FR 基准 Equal or similar, the first n+2 hours are based on FR 基准 Production; Among them, FR0 is the fuel ratio in the hour when high furnace temperature occurs.

8. The method for rapidly reducing the temperature of a blast furnace according to claim 7, wherein: In S4, the total amount of fuel ratio FR is deducted from the n+1 hour and the n+2 hour. 多出 , so that the average fuel ratio in the first n+2 hours is With FR 基准 Equal or similar, the first n+3 hours are based on FR 基准 Production, Among them, FR1 is the fuel ratio in the first hour after the high furnace temperature appears.

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