Blast furnace hearth slag iron storage management and control method

Abstract

A blast furnace hearth slag iron storage management and control method comprises the specific steps that firstly, a blast furnace hearth slag iron stock and hearth slag iron discharging model is established, and the model comprises a theoretical iron amount accumulation module, a theoretical slag amount accumulation module, an actual tapping amount accumulation module, an actual tapping amount accumulation module, a real-time iron amount difference module and a real-time slag amount difference module; 2, obtaining the material batch added in unit time, calculating the theoretical slag iron amount, comparing the theoretical slag iron amount with the actual slag iron amount in front of the furnace, obtaining the slag iron amount difference, and judging the position of the slag iron liquid level in the blast furnace hearth; and 3, comparing the position of the slag iron liquid level in the blast furnace hearth with a set value, and giving an alarm if the position exceeds a set threshold value. According to the invention, the real-time dynamic monitoring of the blast furnace slag tapping state in the blast furnace production process is realized, the display form is visual, and the production safety is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of ironmaking control, and in particular relates to a blast furnace hearth slag iron storage control method. Background Art

[0002] The discharge of slag in front of the blast furnace plays a very important role in the stability of the blast furnace. The blast furnace is a very complex high-temperature and high-pressure environment. The continuous discharge of slag in front of the furnace is very important for the stable operation and safe production of the blast furnace. When the discharge rate of slag is lower than the production speed, it will lead to a decrease in the permeability of the blast furnace, a decrease in the blast kinetic energy, an increase in the slag retention rate in the blast furnace, and an increase in the slag liquid level in the furnace. If the slag is not discharged in time, the accumulated slag reaches the safe capacity, which will lead to safety accidents such as slag filling at the tuyere and burning of tuyere equipment. In the blast furnace production process, the accumulation of slag in the blast furnace hearth is kept under control at any time to provide a basis for the blast furnace operators and to take measures to strengthen the discharge of slag when necessary. The storage monitoring model of slag in the hearth is of great significance for guiding blast furnace production operations.

[0003] At present, in blast furnace production, operators also use online monitoring systems to track and monitor the instantaneous flow rate of slag iron out of the blast furnace during the iron-discharging process. The batch iron amount of the ore can be used to timely measure the amount of iron generated in minutes, and a rough comparison can be made. However, there is no precise and highly quantified information. It is impossible to determine the position of the slag iron liquid level after the slag iron is insufficient in production, the extent of the impact of the slag iron accumulation on the blast furnace production, and the safety problems that may arise after a large amount of slag iron is insufficient in the current furnace. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention proposes a blast furnace hearth slag iron storage control method that can predict the degree of influence of slag iron on the blast furnace when the blast furnace is blocked, and provide a reference basis for blast furnace operators in a timely and effective manner during the slag iron discharge process. The specific technical scheme is as follows:

[0005] A method for managing and controlling slag storage in a blast furnace hearth, characterized in that the specific steps are:

[0006] Step 1: Establish a slag iron inventory in the blast furnace hearth and a hearth slag iron model, which includes a theoretical iron amount accumulation module, a theoretical slag amount accumulation module, an actual iron amount accumulation module, an actual slag amount accumulation module, a real-time iron amount difference module, and a real-time slag amount difference module;

[0007] Step 2: Obtain the batch of material added per unit time to calculate the theoretical slag iron amount, compare it with the actual slag iron amount discharged from the furnace, obtain the slag iron amount difference, and determine the position of the slag iron liquid level in the blast furnace hearth;

[0008] Step 3: Compare the position of the slag iron liquid level in the blast furnace hearth with the set value. If it exceeds the set threshold, an alarm will be issued.

[0009] As an optimization: in the first step, the calculation method of the cumulative theoretical iron quantity module is specifically obtained according to the comprehensive iron content of each batch of materials, and the calculation formula is: the comprehensive grade in the furnace × the ore batch weight;

[0010] The calculation method of the cumulative theoretical slag quantity module is specifically to calculate the theoretical slag output according to the Cao balance principle, and the calculation formula is: the total weight of calcium oxide charged into the furnace in each batch of materials ÷ the Cao content in the blast furnace slag = the theoretical slag output of each batch of materials.

[0011] As an optimization: in the third step, the calculation method of the safety threshold in the blast furnace hearth is as follows. First, calculate the volume of the blast furnace hearth. According to the hearth diameter and the height from the iron notch center line to the tuyere center line, the volume calculation formula is V = πr 2 h, where r is the hearth radius and h is the height of the safe slag and iron holding capacity in the hearth;

[0012] Secondly, calculate the safe slag and iron holding capacity of the blast furnace hearth. The density of molten iron is taken as 7.0t / m 3 and the density of slag is taken as 2.6t / m 3 , and the filling coefficient of liquid slag and iron in the hearth is 0.3 - 0.33. The safe slag and iron volume of the hearth can be calculated through the various dimensional parameters of the hearth. T_security = 0.6×π / 4×D 2 ×(h - 0.5)×60%; or T_security = 0.6×π / 4×D 2 ×h / 2;

[0013] In the formula: 0.6: safety factor; 60%: the volume ratio of iron quantity to the "safe liquid volume"; h: the distance from the tuyere center line to the iron notch center line, m; h - 0.5: the distance from 0.5m below the tuyere center line to the iron notch center line, m.

[0014] In the real-time slag quantity difference module, the display interface uses red to represent molten iron and orange to identify slag. The red molten iron is at the bottom and the orange slag is on the top, with clear layers for easy observation. The height of the blast furnace hearth is divided in a stepped manner according to a proportion, showing the shape and contour of the hearth, and marking the positions of the iron notch center line and the lower edge of the tuyere according to a proportion. The position of the lower edge of the tuyere is the warning line for the hearth stock. Among them, the display color of the warning line is different from the colors of other lines in the interface.

[0015] The beneficial effects of the present invention are as follows: the numerical value of the slag and iron quantity stored in the hearth can be set or cleared by the operator himself. In the actual production of the blast furnace, the slag and iron quantity generated per minute and the minute slag and iron flow flowing out from the actual iron notch in front of the furnace are compared. If the actual slag and iron output is greater than or less than the generated slag and iron quantity, it reminds the operator of the current trend state of the slag and iron storage in the hearth. It realizes the real-time dynamic monitoring of the slag and iron output state of the blast furnace during the production process, and the display form is intuitive, improving the production safety. Detailed Embodiments

[0016] The following elaborates on the preferred embodiments of the present invention in detail, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making the protection scope of the present invention more clearly defined.

[0017] Embodiment 1:

[0018] A blast furnace case with a furnace volume of 2500m is used to further illustrate the present invention. 3

[0019] A method for controlling the storage of slag and iron in the blast furnace hearth, the specific steps are as follows:

[0020] S1. In the control system of a 2500m 3 blast furnace, a program for the inventory of slag and iron in the blast furnace hearth is compiled, a record table of the slag and iron discharge model of the hearth is established, and modules for cumulative theoretical iron amount, cumulative theoretical slag amount, cumulative actual iron output, cumulative actual slag output, real-time iron amount difference, and real-time slag amount difference are set respectively. Six parameter display windows are set at the parameter position of the operation screen.

[0021] The basic data of the 2500m 3 dynamic model are as follows:

[0022] The theoretical iron output per batch of materials is obtained according to the comprehensive iron content of each batch of materials. The calculation formula is: the comprehensive grade of the furnace charge × the ore batch weight. In actual production, the grade is 58%, the ore batch weight is 72t / ch, and the theoretical iron amount = 58% × 72 = 41.76t. The occupied volume is: 41.76 ÷ 7 = 5.96m 3 .

[0023] The theoretical slag output per batch of materials is calculated according to the Cao balance principle. The calculation formula is: the total weight of Cao charged into the furnace per batch of materials ÷ the Cao content in the blast furnace slag = the theoretical slag output per batch of materials. The actual Cao charged into the furnace is 5.67t / batch, and the Cao in the blast furnace slag is 40%. The theoretical slag amount = 5.67 ÷ 40% = 14.17t, and the occupied volume is: 14.17 ÷ 2.6 = 5.45m 3 .

[0024] The volume of the blast furnace hearth is calculated. According to the hearth diameter and the height from the iron notch center line to the lower edge of the tuyere, the volume calculation formula is V = πr 2 h, where r is the hearth radius and h is the effective height of the hearth. Given that the hearth diameter of this blast furnace is 11.2m and the effective height h from the tuyere center line to the lower edge of the iron notch is 3.6 meters, V_an is the safe slag and iron volume. According to the formula V_an = 3.14 × 5.6 2 × 3.6 × 0.6 = 212.3m 3 .

[0025] ​Calculate the safe slag and iron capacity of the blast furnace hearth, and take the density of molten iron as 7.0t / m 3 The density of slag is 2.6t / m 3 , the filling factor ratio of liquid slag iron in the furnace is 0.33. Note: The filling factor refers to the liquid slag iron in the furnace.

[0026] The ratio of the filled volume to the geometric volume of the filled part of the furnace.

[0027] Calculation shows that the safe slag and iron capacity of the blast furnace hearth is: 212.3÷0.33=643.3t, indicating that this value is the maximum amount of slag and iron stored in the hearth.

[0028] The theoretical slag volume is calculated by the batches of material loaded per unit time, and compared with the actual slag volume in front of the furnace, the slag volume difference is calculated, and the position of the slag liquid level in the blast furnace hearth is determined. Assuming that the number of batches of material loaded per hour is 7 batches / hour, the theoretical volume is (5.96+5.45)×7=79.87m 3 For example, if the amount of slag iron in front of the furnace is small, the slag iron is 150t per hour, and the volume occupied is 150×0.33=49.5m 3 .

[0029] The volume of the real-time slag iron liquid level rise = theoretical slag iron volume - the actual slag iron volume discharged from the furnace. 79.87-49.5=30.37m 3

[0030] Each time a batch of materials is added, the slag iron surface automatically rises by one blast furnace. When tapping iron, the height of the slag iron surface can be automatically adjusted in real time according to the slag iron flow, or it can be adjusted by manual calculation. The height of the slag iron liquid level in the furnace is h = 30.37 ÷ 3.14 ÷ 5.6 2 =0.31m. This indicates that the blast furnace production is affected by the small slag iron flow in front of the furnace, and the slag iron liquid level in the furnace rises by 0.31m per hour.

[0031] The color of the molten iron and slag at the interface of the model slag iron can be distinguished. Red indicates molten iron, and orange indicates slag. The red molten iron is at the bottom, and the orange slag is at the top. The layers are clear and cannot be mixed. The slag iron line at this interface shows an upward trend.

[0032] Divide the height of the blast furnace hearth into proportional steps, with 0.1m as a scale, draw the shape and outline of the hearth, mark the center line of the iron mouth and the position of the lower edge of the tuyere in proportion, and mark the position of the lower edge of the tuyere with a special color, which is the warning line for the arrival of the furnace hearth inventory.

[0033] The height from the center line of the iron mouth to the lower edge of the tuyere is marked, and according to the actual slag and iron discharge situation in the blast furnace hearth, the operator is reminded to strengthen the iron discharge or take measures to reduce the smelting strength and control the amount of slag and iron generated.

[0034] According to the above slag flow, the process operation screen can display 120t of net slag, which is set as a blue flashing warning. The current distance from the slag surface to the lower edge of the tuyere is 1.5m, reminding the operator of the current storage trend of slag in the furnace.

[0035] When the slag iron level in the furnace continues to rise, and the slag iron liquid level is 1 meter away from the lower edge of the tuyere, a yellow alarm pops up automatically. When the slag iron liquid level is 0.5 meter away from the lower edge of the tuyere, a red alarm pops up automatically, and the operation screen displays the words "slag iron is being held back and iron discharge needs to be intensified."

[0036] Embodiment 2:

[0037] Combined 2200m 3 The present invention is further illustrated by the case of a blast furnace.

[0038] A method for managing and controlling slag iron storage in a blast furnace hearth, comprising the following specific steps:

[0039] Compilation 2200m 3 The basic data of the dynamic model are as follows:

[0040] The theoretical iron output of a batch of materials is calculated based on the comprehensive iron content of each batch of materials. The calculation formula is: comprehensive grade of the furnace × ore batch weight. The actual production grade is 57%, the ore batch weight is 68t / ch, and the theoretical iron content = 57% × 68 = 38.76t. The volume occupied is: 38.76÷7 = 5.537m 3 .

[0041] The theoretical slag discharge of a batch of materials is calculated according to the principle of grass balance. The calculation formula is: the total weight of grass in each batch of materials ÷ grass content in blast furnace slag = theoretical slag discharge of each batch of materials. The actual grass in the furnace is 5.355t / batch, 38% of blast furnace slag, theoretical slag amount = 5.355÷38% = 14.09t, and the volume occupied is: 14.09÷2.6 = 5.42m 3 .

[0042] Calculate the volume of the blast furnace hearth. According to the hearth diameter and the height from the center line of the iron mouth to the lower edge of the tuyere, the volume calculation formula is V = πr2h, where r is the radius of the hearth and h is the effective height of the hearth. It is known that the diameter of the blast furnace hearth is 10.8m, and the height from the center line of the tuyere to the lower edge of the iron mouth is 2.0 meters. According to the formula V = 3.14 × 5.4 × 5.4 × 2.0 = 183.1248m 3 .

[0043] Calculate the safe slag and iron capacity of the blast furnace hearth, and take the density of molten iron as 7.0t / m 3 The density of slag is 2.6t / m 3, the filling coefficient ratio of liquid slag iron in the furnace is 0.33. Note: The filling coefficient refers to the ratio of the volume filled by liquid slag iron in the furnace to the geometric volume of the filled part of the furnace.

[0044] Calculation shows that the safe slag and iron capacity of the blast furnace hearth is: 183.1248÷0.33=554.923t, indicating that this value is the maximum amount of slag and iron stored in the hearth.

[0045] The theoretical slag volume is calculated by the batches of material loaded per unit time, and compared with the actual slag volume in front of the furnace, the slag volume difference is calculated, and the position of the slag liquid level in the blast furnace hearth is determined. According to the number of batches of material loaded per hour is 6.5 batches / hour, the theoretical volume is (5.537+5.42)×6.5=70.16m 3 ; 140t of slag iron per hour, the volume occupied is 140×0.33=46.2m 3 .

[0046] The volume of the real-time slag iron liquid level rise = theoretical slag iron volume - the actual volume of slag iron discharged from the furnace. 70.16-46.2=27.56m 3 , each time a batch of materials is added, the slag iron surface automatically rises a height. When tapping iron, the height of the slag iron surface can be automatically adjusted in real time according to the slag iron flow, or it can be adjusted by manual calculation. The height of the slag iron liquid level in the furnace is h=27.56÷3.14÷5.42÷5.42=0.298m. It shows that the blast furnace production is affected by the small slag iron flow in front of the furnace, and the slag iron liquid level in the furnace rises by 0.298m per hour.

[0047] The color of the molten iron and slag in the system model slag-iron interface can be distinguished, red represents molten iron, orange represents slag, molten iron (red) is at the bottom, slag orange is at the top, the layers are clear and cannot be mixed. The slag-iron line of this interface shows an upward trend.

[0048] Divide the height of the blast furnace hearth into proportional steps, with 0.2m as a scale, draw the shape and outline of the hearth, mark the center line of the iron mouth and the position of the lower edge of the tuyere in proportion, and mark the position of the lower edge of the tuyere with different colors. This is the warning line for the arrival of the furnace hearth inventory.

[0049] The height from the center line of the iron mouth to the lower edge of the tuyere is marked, and according to the actual slag and iron discharge situation in the blast furnace hearth, the operator is reminded to strengthen the iron discharge or take measures to reduce the smelting strength and control the amount of slag and iron generated.

[0050] According to the above slag flow, the process operation screen can display 100t of net slag, set to a blue flashing warning, and the current distance from the slag surface to the lower edge of the tuyere is 1.5m, reminding the operator of the current storage trend of slag in the furnace.

[0051] When the slag iron level in the furnace continues to rise, and the slag iron liquid level is 1.2 meters away from the lower edge of the tuyere, the computer program automatically pops up a yellow alarm. When the slag iron liquid level is 0.8 meters away from the lower edge of the tuyere, the computer program automatically pops up a red alarm, and the computer screen displays the words "slag iron is being accumulated and iron discharge needs to be intensified."

[0052] Example 3: Combined with 3200m 3 The present invention is further explained in the case of blast furnace

[0053] A method for managing and controlling slag iron storage in a blast furnace hearth, comprising the following specific steps:

[0054] Compilation 3200m 3 The basic data of the dynamic model are as follows:

[0055] The theoretical iron output of a batch of materials is calculated based on the comprehensive iron content of each batch of materials. The calculation formula is: comprehensive grade of the furnace × ore batch weight. In actual production, the grade is 59%, the ore batch weight is 100t / ch, and the theoretical iron content = 59% × 100 = 59t. The volume occupied is: 59÷7 = 8.42m 3 .

[0056] The theoretical slag discharge of a batch of materials is calculated according to the principle of grass balance. The calculation formula is: the total weight of grass in each batch of materials ÷ grass content in blast furnace slag = theoretical slag discharge of each batch of materials. The actual grass in the furnace is 7.86t / batch, 40% of blast furnace slag, theoretical slag amount = 7.86÷40% = 19.65t, and the volume occupied is: 19.65÷2.6 = 7.55m 3 .

[0057] Calculate the volume of the blast furnace hearth. According to the hearth diameter and the height from the center line of the iron mouth to the lower edge of the tuyere, the volume calculation formula is V = πr2h, where r is the radius of the hearth and h is the effective height of the hearth. It is known that the diameter of the blast furnace hearth is 14.6m, and the height from the center line of the tuyere to the lower edge of the iron mouth is h is 2.8m. According to the formula V = 3.14 × 7.3 × 7.3 × 2.8 = 468.52m 3 .

[0058] Calculate the safe slag and iron capacity of the blast furnace hearth, and take the density of molten iron as 7.0t / m 3 The density of slag is 2.6t / m 3 , the filling coefficient ratio of liquid slag iron in the furnace is 0.33. Note: The filling coefficient refers to the ratio of the volume filled by liquid slag iron in the furnace to the geometric volume of the filled part of the furnace.

[0059] Calculation shows that the safe slag and iron capacity of the blast furnace hearth is: 468.52÷0.33=1419.77t, indicating that this value is the maximum amount of slag and iron stored in the hearth.

[0060] The theoretical slag volume is calculated by the batches of material loaded per unit time, and compared with the actual slag volume in front of the furnace, the slag volume difference is calculated, and the position of the slag liquid level in the blast furnace hearth is determined. Assuming that the number of batches of material loaded per hour is 6 batches / hour, the theoretical volume is (8.42+7.55)×6=95.82m 3 ; 340t of slag iron per hour, the volume occupied is 340×0.33=46.2m 3 .

[0061] The volume of the real-time slag iron liquid level rise = theoretical slag iron volume - the actual slag iron volume discharged from the furnace. 95.82-46.2=49.62m 3

[0062] Each time a batch of materials is added, the slag iron surface automatically rises a certain height. When tapping iron, the height of the slag iron surface can be automatically adjusted in real time according to the slag iron flow, or the liquid level can be adjusted by manual calculation. The height of the slag iron liquid level in the furnace is h = 49.62 ÷ 3.14 ÷ 7.3 ÷ 7.3 = 0.296m. This shows that the blast furnace production is affected by the small slag iron flow in front of the furnace, and the slag iron liquid level in the furnace rises by 0.296m per hour.

[0063] The color of the molten iron and slag in the system model slag-iron interface can be distinguished, red represents molten iron, orange represents slag, molten iron (red) is at the bottom, slag orange is at the top, the layers are clear and cannot be mixed. The slag-iron line of this interface shows an upward trend.

[0064] Divide the height of the blast furnace hearth into proportional steps, with 0.5m as a scale, draw the shape and outline of the hearth, mark the center line of the iron mouth and the position of the lower edge of the tuyere in proportion, and mark the position of the lower edge of the tuyere with different colors. This is the warning line for the arrival of the furnace hearth inventory.

[0065] The height from the center line of the iron mouth to the lower edge of the tuyere is marked, and according to the actual slag and iron discharge situation in the blast furnace hearth, the operator is reminded to strengthen the iron discharge or take measures to reduce the smelting strength and control the amount of slag and iron generated.

[0066] According to the above slag flow, the process operation screen can display 200t of net slag, which is set as a blue flashing warning. The current distance from the slag surface to the lower edge of the tuyere is 0.8m, reminding the operator of the current storage trend of slag in the furnace.

[0067] When the slag iron level in the furnace continues to rise, and the slag iron liquid level is 0.5 meters away from the lower edge of the tuyere, the computer program automatically pops up a yellow alarm. When the slag iron liquid level is 0.3 meters away from the lower edge of the tuyere, the computer program automatically pops up a red alarm, and the computer screen displays the words "slag iron is being accumulated and iron discharge needs to be intensified."

Claims

1. A method for controlling the storage of slag iron in a blast furnace, characterized in that: The specific steps are: Step 1: Establish a slag iron inventory in the blast furnace hearth and a hearth slag iron model, which includes a theoretical iron amount accumulation module, a theoretical slag amount accumulation module, an actual iron amount accumulation module, an actual slag amount accumulation module, a real-time iron amount difference module, and a real-time slag amount difference module; Step 2: Obtain the batch of material added per unit time to calculate the theoretical slag iron amount, compare it with the actual slag iron amount discharged from the furnace, obtain the slag iron amount difference, and determine the position of the slag iron liquid level in the blast furnace hearth; Step 3: Compare the position of the slag iron liquid level in the blast furnace hearth with the set value. If it exceeds the set threshold, an alarm will be issued.

2. The method for controlling slag storage in a blast furnace according to claim 1, characterized in that: In the step 1, the calculation method of the theoretical iron accumulation module is specifically obtained according to the comprehensive iron content of each batch of materials, and the calculation formula is: comprehensive grade of the furnace × ore batch weight; The calculation method of the theoretical slag amount accumulation module is specifically to calculate the theoretical slag amount according to the Cao balance principle. The calculation formula is: the total weight of calcium oxide entering the furnace in each batch of materials ÷ Cao content in blast furnace slag = theoretical slag amount of each batch of materials.

3. The blast furnace slag storage management and control method according to claim 1, characterized in that: In the step 3, the calculation method of the safety threshold in the blast furnace hearth is as follows: first, the volume of the blast furnace hearth is calculated, and according to the hearth diameter and the height from the center line of the iron mouth to the center line of the tuyere, the volume calculation formula is V=πr 2 h, where r is the radius of the furnace and h is the height of the furnace to safely hold the slag and iron; Secondly, calculate the safe slag and hot metal volume in the BF hearth. The density of hot metal is taken as 7.0 t / m 3 , and the density of slag is taken as 2.6 t / m 3 . The filling coefficient of liquid slag and hot metal in the hearth is 0.3 - 0.

33. Through the various dimensional parameters of the hearth, the safe slag and hot metal volume in the hearth can be calculated. T_ safety = 0.6×π / 4×D 2 ×(h - 0.5)×60%; or T_ safety = 0.6×π / 4×D 2 ×h / 2; In the formula: 0.6: safety factor; 60%: volume ratio of iron to "safe liquid capacity"; h: distance from the center line of the tuyere to the center line of the taphole, m; h-0.5: distance from 0.5m below the center line of the tuyere to the center line of the taphole, m.

4. The method for controlling slag storage in a blast furnace according to claim 1, characterized in that: In the real-time slag quantity difference module, the display interface uses red to represent molten iron and orange to represent slag. The red molten iron is at the bottom and the orange slag is at the top. The layers are clear and easy to observe. The height of the blast furnace hearth is divided into proportional steps to show the shape and outline of the hearth. The center line of the iron mouth and the position of the lower edge of the tuyere are marked in proportion. The position of the lower edge of the tuyere is the warning line for the arrival of the hearth inventory. The display color of the warning line is different from the color of other lines in the interface.