Blast furnace gas flow determination method, blast furnace equipment, and blast furnace operation method

Abstract

To provide a technology capable of accurately detecting an abnormality of a gas flow in a blast furnace such as an excessive flow in a furnace wall.SOLUTION: In a blast furnace gas flow determination method for determining a gas flow of a blast furnace main body in a blast furnace facility, an extraction heat amount of furnace wall cooling equipment for cooling the furnace wall of the blast furnace main body is calculated, and the abnormality of the gas flow of the blast furnace main body is determined from the calculated value of the extraction heat amount.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a blast furnace gas flow determination method for determining an abnormality in a blast furnace gas flow, a blast furnace facility, and a blast furnace operation method. [Background technology]

[0002] In blast furnace operation, understanding the gas flow inside the furnace is extremely important. The reduction rate of the charged materials varies depending on the gas flow state, which significantly affects operational performance such as productivity and fuel ratio. Furthermore, improper circumferential gas flow, such as uneven circumferential gas flow, is known to cause deterioration of furnace conditions, such as poor permeability throughout the furnace, deposition on the furnace walls, blow-through, hanging, and slippage. In particular, excessive gas flow on the furnace wall in a specific circumferential region is called excessive furnace wall flow, and excessive furnace wall flow is likely to cause deterioration of furnace conditions.

[0003] A known method for determining gas flow in a blast furnace is described in Patent Document 1. The technology described in Patent Document 1 involves providing a horizontal gas sampler that detects gas temperatures at multiple positions between the furnace wall and the core on the stock line of the blast furnace throat, a skin flow sampler that detects the temperature near the furnace wall, and a furnace wall brick thermometer, and determining the gas flow throughout the blast furnace, including excessive furnace wall flow, mainly based on the temperature signals from these samples. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 63-243215 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the method described in Patent Document 1, the gas temperature near the furnace wall is standardized to calculate the index, making it difficult to quantitatively determine the positional information of the temperature deviation in the circumferential direction of the blast furnace. Furthermore, measurements using a thermometer are performed at points in both the height direction and the circumferential direction, making it difficult to estimate a continuous temperature distribution. Therefore, it is not possible to quantitatively determine the gas flow, including the positional information in the circumferential direction of the blast furnace, and it is not possible to accurately determine gas flow abnormalities such as excessive furnace wall flow.

[0006] Therefore, the present invention provides a technique capable of accurately detecting abnormalities in gas flow in a blast furnace, such as excessive furnace wall flow. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides the following [1] to [9].

[0008] [1] A blast furnace gas flow determination method for determining the gas flow of a blast furnace body in a blast furnace facility, A blast furnace gas flow determination method, which calculates a heat dissipation amount of furnace wall cooling equipment that cools the furnace wall of the blast furnace body, and determines an abnormality in the gas flow of the blast furnace body from the calculated value of the heat dissipation amount.

[0009] [2] The blast furnace gas flow determination method according to [1], which calculates the heat transfer amount of the furnace wall cooling equipment at a plurality of positions in the circumferential direction of the blast furnace body, and determines that excessive furnace wall flow has occurred as an abnormality in the gas flow if the standard deviation of the heat transfer amount in the circumferential direction exceeds a predetermined threshold value.

[0010] [3] Among a plurality of positions in the circumferential direction of the blast furnace body, the position where the heat extraction amount exceeds a predetermined threshold is determined to be the position where the excessive furnace wall flow has occurred. [2] The blast furnace gas flow determination method described.

[0011] [4] A blast furnace gas flow determination method according to any one of [1] to [3], which calculates the heat dissipation amount of the furnace wall cooling equipment at multiple positions in the circumferential direction of the blast furnace body, and determines that an attachment has occurred if the heat dissipation amount falls below a predetermined threshold value.

[0012] [5] A blast furnace body where the blast furnace reaction occurs; a gas flow determination unit for determining the gas flow of the blast furnace body; and The blast furnace body has furnace wall cooling equipment for cooling the furnace wall, The gas flow determination unit calculates a heat radiation amount of the furnace wall cooling equipment and determines an abnormality in the gas flow of the blast furnace body from the calculated value of the heat radiation amount.

[0013] [6] The blast furnace equipment described in [5], wherein the gas flow determination unit calculates the heat dissipation amount of the furnace wall cooling equipment at multiple positions in the circumferential direction of the blast furnace body, and determines that excessive furnace wall flow has occurred as an abnormality in the gas flow if the standard deviation of the heat dissipation amount in the circumferential direction exceeds a predetermined threshold value.

[0014] [7] The blast furnace equipment described in [6], wherein the gas flow determination unit determines, among a plurality of positions in the circumferential direction of the blast furnace body, a position where the amount of heat dissipation exceeds a predetermined threshold value as the position where the excessive furnace wall flow has occurred.

[0015] [8] A blast furnace facility described in any one of [5] to [7], wherein the gas flow determination unit calculates the heat dissipation amount of the furnace wall cooling equipment at multiple positions in the circumferential direction of the blast furnace body, and determines that an attachment has formed if the heat dissipation amount falls below a predetermined threshold value.

[0016] [9] A step of calculating the heat dissipation amount of the furnace wall cooling equipment that cools the furnace wall of the blast furnace body, and determining an abnormality in the gas flow of the blast furnace body from the calculated value of the heat dissipation amount; When the gas flow is determined to be abnormal, changing the burden distribution and / or the gas flow rate to the blast furnace body so that the abnormality in the gas flow is eliminated; A blast furnace operating method comprising the steps of: [Effects of the Invention]

[0017] According to the present invention, the heat dissipation amount of the furnace wall cooling equipment that cools the furnace walls of the blast furnace body is calculated, and an abnormality in the gas flow in the blast furnace body is determined from the calculated value of the heat dissipation amount, so that an abnormality in the gas flow in the blast furnace, such as excessive furnace wall flow, can be accurately detected. Then, by changing the burden distribution and air flow rate to the blast furnace in response to the detected abnormality in the gas flow, it is possible to perform blast furnace operation with excellent stability. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a cross-sectional view showing an example of blast furnace equipment. [Figure 2] FIG. 2 is a cross-sectional view showing a cooling stave for cooling the furnace wall of the blast furnace body. [Figure 3] FIG. 3 is a schematic diagram for explaining the installation state of cooling pipes of the cooling stave of FIG. 2. [Figure 4] FIG. 3 is a schematic diagram for explaining an example of a cooling water supply structure for the cooling stave of FIG. 2. [Figure 5] FIG. 2 is a block diagram showing an example of a blast furnace gas flow determination unit in a blast furnace facility. [Figure 6] 1 is a flowchart illustrating a flow of an example of a blast furnace gas flow determination method. [Figure 7] FIG. 1 is a block diagram for explaining the correlation between excessive furnace wall flow and the amount of heat extraction. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0020] <Blast furnace equipment> First, the blast furnace equipment will be described. 1 is a cross-sectional view showing an example of a blast furnace facility according to this embodiment. The blast furnace facility 1 has a blast furnace body 100 and a blast furnace gas flow determining unit 200.

[0021] Raw materials consisting mainly of iron ore and coke are charged into the blast furnace body 100 by a charging device (not shown) installed at the top of the furnace. A plurality of tuyere ports 110 for blowing hot air to cause a reaction in the furnace are arranged circumferentially at the bottom of the furnace, and hot air is blown into the blast furnace body 100 from blower pipes 111 via these tuyere ports 110. In the area blown from the tuyere ports 110, a raceway 112 is formed, which is a space formed when the hot air blown in from the tuyere ports 110 pushes away the coke. At the bottom of the furnace, there is a basin portion 113 where the molten iron and slag produced by the reaction in the furnace accumulate.

[0022] The furnace wall 101 of the blast furnace body 100 is constructed such that the outer surface of the refractory material is covered with a steel shell 101a, and a cooling stave (CS) 102, which is a furnace wall cooling device for preventing the steel shell 101a from overheating, is provided inside the steel shell 101a.

[0023] As shown in Fig. 2, the cooling stave 102 has a structure in which cooling pipes 103 are cast in a base material 104. As shown in Fig. 3, the cooling pipes 103 are laid out in the height direction and circumferential direction of the blast furnace body 100 so that their surface area is as large as possible in order to maximize cooling efficiency. If the cooling stave is damaged, the cooling pipes will break and cooling water will flood into the furnace, so flow meters may be installed to monitor the supply and discharge flow rates of cooling water.

[0024] An example of the cooling water supply structure of the cooling stave 102 is shown in Fig. 4. The cooling system A in which the cooling stave 102 is located includes a cooling pipe 103a and a water supply flow meter F for measuring the water supply flow rate of the cooling system. 11 and a drainage flow meter F that measures the drainage flow rate. 12 The cooling water in the cooling pipe 103a is stored in a head tank 104a and circulated by a pump 105a. The cooling system B directly above the cooling system A has a cooling pipe 103b and a water supply flow meter F for measuring the water supply flow rate of the cooling system. 13 and a drainage flow meter F that measures the drainage flow rate. 14The cooling water in the cooling pipe 103b is stored in a head tank 104b and circulated by a pump 105b. There are, for example, about 40 such upper and lower cooling systems in the circumferential direction, and the other cooling systems are configured in the same way. 11 and F 13 and drainage flow meter F 12 and F 14 The device has a pipe temperature measurement function to detect water leaks in the event of a pipe breakage, and can measure the supply water temperature and discharge water temperature.

[0025] In addition, Figure 4 shows an example in which a flow meter with a pipe temperature measurement function is used to monitor the cooling water supply flow rate and drainage flow rate, but a thermometer to measure the supply water temperature and drainage temperature and a flow meter to measure the flow rate may also be installed separately.

[0026] The blast furnace gas flow determination unit 200 calculates the amount of heat removed in the circumferential direction in the cooling stave 102, determines the furnace wall gas flow based on the calculated amount of heat, and detects abnormalities in the gas flow such as excessive furnace wall flow. As shown in FIG. 5, the blast furnace gas flow determination unit 200 has a calculation unit 210 and a memory unit 220.

[0027] The calculation unit 210 has a temperature / flow rate actual value import unit 211, a heat transfer amount calculation unit 212, a heat transfer amount standard deviation calculation unit 213, an excess furnace wall flow determination unit 214, an excess furnace wall flow occurrence location determination unit 215, and a furnace wall deposit formation determination unit 216.

[0028] The temperature and flow rate record acquisition unit 211 is, for example, a water supply flow meter F 11 and F 13 and drainage flow meter F 12 and F 14 The actual temperature and flow rate data on the water supply side and the water discharge side are acquired based on the measured values ​​of the temperature meter and the flow rate data. As described above, the actual temperature and flow rate data may be acquired from a separately provided thermometer and a separately provided flow rate meter.

[0029] The heat radiation amount calculation unit 212 calculates the heat radiation amount of the coolant for each cooling system based on the actual temperature and flow rate data for the water supply side and the water discharge side for each cooling system, which are input to the temperature and flow rate data input unit 211. At this time, the heat radiation amount of the coolant can be calculated as follows. Amount of heat removed = (wastewater temperature - supply water temperature) x flow rate x density x specific heat The heat dissipation amount calculation unit 212 can calculate the amount of heat dissipation in the circumferential direction of the cooling stave 102 from the calculation results for each cooling system. That is, each cooling system functions as a measurement point, and the amount of heat dissipation at each measurement point in the circumferential direction can be calculated.

[0030] The heat extraction amount standard deviation calculation unit 213 calculates the standard deviation of the heat extraction amount in each cooling system in the circumferential direction of the cooling stave 102 obtained by the heat extraction calculation unit 212. This value indicates the uniformity of the circumferential distribution of the furnace wall gas flow (furnace wall flow).

[0031] An excessive furnace wall flow determination unit 214 determines that the furnace wall flow is not uniform and that excessive furnace wall flow has occurred when the standard deviation of the heat transfer rate calculated by the heat transfer rate standard deviation calculation unit 213 exceeds a certain threshold. The threshold value of the standard deviation of the heat transfer rate is set appropriately with reference to the heat transfer rate during normal operation.

[0032] The excessive furnace wall flow occurrence location determination unit 215 determines the position of the cooling system where the amount of heat removed exceeds a threshold set based on the amount of heat removed during normal operation from the calculation results of the amount of heat removed in each cooling system in the circumferential direction of the cooling stave 102, and determines the position of that cooling system as the location where excessive furnace wall flow is occurring.

[0033] The furnace wall deposit formation determination unit 216 determines that furnace wall deposits have formed when the amount of heat removal in each cooling system in the circumferential direction of the cooling stave 102 falls below a preset threshold, based on the calculation result of the amount of heat removal. Specifically, if there is a cooling system in which the amount of heat removal falls below a threshold set based on the amount of heat removal during normal operation, for example, that position is determined to be the furnace wall deposit formation location. When deposits have formed, it is highly likely that gas permeability is obstructed, and it can be considered that a gas flow abnormality has occurred.

[0034] The storage unit 220 stores information necessary for the calculations in the calculation unit 210, the calculation results of the amount of heat removal, locations where excessive furnace wall flow occurs, locations where deposits on the furnace wall are formed, and the like.

[0035] <Blast furnace gas flow determination method> Next, a description will be given of the flow of the blast furnace gas flow determination method in the blast furnace facility 1 configured as above. Fig. 6 is a flowchart for explaining the flow of the blast furnace gas flow determination method.

[0036] First, the temperature and flow rate record acquisition unit 211 acquires the temperature and flow rate records on the water supply side and the drainage side (step ST1). The temperature and flow rate records on the water supply side and the drainage side are acquired, for example, from a water supply flow meter F 11 and F 13 and drainage flow meter F 12 and F 14 can be captured based on measurements of

[0037] Next, the heat extraction calculation unit 212 calculates the amount of heat extraction for each cooling system based on the actual temperature and flow rate data for the water supply side and the water discharge side for each cooling system input into the temperature / flow rate data input unit 211 (step ST2).

[0038] At this time, the heat removal calculation unit 212 calculates the amount of heat removal in each cooling system in the circumferential direction of the cooling stave 102 from the calculation results for each cooling system based on the formula: Amount of heat removal = (wastewater temperature - feedwater temperature) x flow rate x density x specific heat, as described above. In this case, each cooling system functions as a measurement point. The amount of heat removal by the cooling water is correlated with the furnace wall gas flow (furnace wall flow) of the blast furnace, and as shown in Figure 7, when the furnace wall flow increases and excessive furnace wall flow occurs, the furnace wall temperature rises, the temperature of the cooling stave also rises, and the amount of heat removal by the cooling water increases.

[0039] Next, the standard deviation of the heat extraction amount in the circumferential direction is calculated by the heat extraction amount standard deviation calculation unit 213 from the heat extraction amount obtained in each cooling system in the circumferential direction of the cooling stave 102 (step ST3).

[0040] Next, based on the standard deviation of the heat transfer rate calculated by the heat transfer rate standard deviation calculation unit 213, the furnace wall flow excess determination unit 214 determines whether or not excessive furnace wall flow has occurred (step ST4). Here, if the standard deviation of the heat transfer rate exceeds a predetermined threshold, it is determined that the furnace wall flow is not uniform and excessive furnace wall flow has occurred. In other words, if the standard deviation of the heat transfer rate is large, it is considered that there is a location (cooling system) where the heat transfer rate is significantly high, and it is determined that excessive furnace wall flow has occurred at that location.

[0041] If it is determined that excessive wall flow has occurred, an abnormality is output to a control unit (not shown) that controls operation (step ST5), and at the same time, the excessive wall flow occurrence location determination unit 215 determines the location of excessive wall flow (step ST6). In this determination, from the calculation results of the heat radiation amount at each measurement location (cooling system) in the circumferential direction of the cooling stave 102, the position of the cooling system where the heat radiation amount exceeds a threshold set based on the heat radiation amount during normal operation is obtained, and that position is determined to be the location of excessive wall flow. Then, the actual results of the location of excessive wall flow occurrence are stored in the memory unit.

[0042] Next, the furnace wall deposit formation determination unit 216 determines that furnace wall deposits have formed when the amount of heat dissipation is below a preset threshold based on the calculation results of the amount of heat dissipation in each cooling system in the circumferential direction of the cooling stave 102 (step ST7). Then, the actual results of the locations where furnace wall deposits have formed are stored in the memory unit. The determination that furnace wall deposits have formed is made by determining that the location of a cooling system where the amount of heat dissipation is below a threshold set based on the amount of heat dissipation during normal operation, for example, is the location where deposits have formed on the furnace wall.

[0043] As described above, a method for determining excessive gas flow at the furnace wall, etc., based on a predetermined index described in Patent Document 1 is known as a method for determining gas flow in a blast furnace. However, the technology in Patent Document 1 standardizes the gas temperature near the furnace wall to calculate the index, making it difficult to quantitatively determine positional information on temperature deviation in the circumferential direction of the furnace. Furthermore, measurements using a thermometer are performed at points in both the height direction and the circumferential direction, making it difficult to estimate continuous temperature distribution. For this reason, it is not possible to quantitatively determine gas flow, including positional information in the circumferential direction of the blast furnace, and there is a problem in that it is not possible to accurately determine gas flow abnormalities such as excessive furnace wall flow.

[0044] Therefore, in this embodiment, the cooling stave 102, which is furnace body cooling equipment installed on the furnace wall, calculates the heat transfer amount for each cooling system based on the actual temperature and flow rate records on the water supply side and discharge side of each of multiple cooling systems in the circumferential direction of the blast furnace, and determines the distribution of the heat transfer amount in the circumferential direction to grasp the circumferential distribution of the gas flow (furnace wall flow) in the blast furnace. Because the cooling stave 102 is equipped with cooling pipes 103 as shown in FIG. 3 above, unlike the thermometers that measure at points as in Patent Document 1, the heat transfer amount for each cooling system can be determined as an area, which is highly accurate. At this time, in order to obtain detailed positional information, it is preferable to calculate the heat transfer amount for as many pipes as possible.

[0045] In this way, in this embodiment, the cooling stave 102 is used to determine the distribution of heat removal in the circumferential direction, so that the circumferential distribution of the gas flow (furnace wall flow) in the blast furnace can be quantitatively grasped, and abnormalities in the gas flow in the blast furnace can be accurately detected.

[0046] Specifically, the standard deviation of the heat transfer rate in the circumferential direction is calculated, and if the value exceeds a predetermined threshold, it is determined that the furnace wall flow is not uniform and that excessive wall flow, a typical gas flow abnormality, has occurred. The location where the heat transfer rate itself exceeds the predetermined threshold is determined to be the location where excessive wall flow has occurred. Furthermore, if the heat transfer rate in the circumferential direction falls below the predetermined threshold, it is determined that furnace wall deposit formation has occurred. When deposits are formed, gas permeability is impaired, and there is a high possibility that gas flow abnormalities have occurred. Note that excessive wall flow and the formation of deposits on the furnace wall have different mechanisms and therefore occur at different times. However, because the formation of deposits on the furnace wall generally takes a relatively long time, excessive wall flow and the formation of deposits on the furnace wall can occur simultaneously.

[0047] In this way, when the gas flow in the blast furnace is determined to be abnormal, as in the case of excessive furnace wall flow, or when the probability of a gas flow abnormality, such as a deterioration in permeability, is determined to be high, as in the case of furnace wall deposit formation, the burden distribution and / or air volume in the blast furnace body are changed to resolve the gas flow abnormality. This enables blast furnace operation with excellent stability. More specifically, excessive furnace wall flow increases the coke rate, but such an increase in the coke rate can be resolved by taking blast furnace operation actions such as reducing the air flow in advance or changing the burden distribution. If deposits on the furnace wall occur, they can be resolved by charging coke several times in succession to promote combustion.

[0048] <Other applications> Although the embodiments of the present invention have been described above, these are merely examples and should not be considered limiting. The above embodiments may be omitted, substituted, or modified in various ways without departing from the spirit of the present invention.

[0049] For example, in the above embodiment, the heat dissipation amount of the cooling water was calculated using the water supply temperature and drainage temperature and flow rate measured by a water supply flow meter and a drainage flow meter with a pipe temperature measurement function, which are installed for the purpose of monitoring the water supply flow rate and drainage flow rate of the cooling water of the cooling stave, but this is not limiting and the heat dissipation amount may also be calculated by a separate means.

[0050] Furthermore, the configuration of the blast furnace gas flow determination unit is not limited to that of the above embodiment, and may be configured as appropriate so as to determine a desired gas flow abnormality in the blast furnace body. [Explanation of symbols]

[0051] 1 Blast furnace equipment 100 Blast furnace body 101 Furnace wall 101a Iron skin 102 Cooling stave (furnace wall cooling equipment) 103, 103a, 103b Cooling piping 200 Blast furnace gas flow determination unit 210 Arithmetic section 211 Temperature and flow rate performance acquisition section 212 Heat extraction calculation unit 213 Heat transfer standard deviation calculation unit 214 Excessive furnace wall flow determination section 215 Excessive wall flow detection section 216 Furnace wall deposit formation determination section 217 Furnace wall deposit generation location determination unit

Claims

1. A blast furnace gas flow determination method for determining a gas flow in a blast furnace body in a blast furnace facility, Calculating the amount of heat removed from a furnace wall cooling system that cools the furnace wall of the blast furnace body at a plurality of positions in the circumferential direction of the blast furnace body using cooling piping that is laid out in the height direction and circumferential direction of the blast furnace body for each of a plurality of cooling systems arranged in the circumferential direction, and determining an abnormality in the gas flow of the blast furnace body from the calculated value of the amount of heat removed; When the standard deviation of the heat transfer amount in the circumferential direction exceeds a predetermined threshold value, it is determined that an excessive furnace wall flow has occurred as an abnormality of the gas flow, and among a plurality of positions in the circumferential direction of the blast furnace body, a position where the heat transfer amount exceeds a predetermined first threshold value is determined to be a position where the excessive furnace wall flow has occurred, A blast furnace gas flow determination method that determines that an attachment has occurred when the amount of heat removal calculated at a plurality of positions in the circumferential direction of the blast furnace body falls below a predetermined second threshold value.

2. a blast furnace body where the blast furnace reaction occurs; a gas flow determination unit for determining the gas flow of the blast furnace body; and The blast furnace body has a furnace wall cooling system having a plurality of cooling systems arranged in a circumferential direction for cooling the furnace wall with cooling piping laid out in the height direction and circumferential direction of the blast furnace body, The gas flow determination unit calculates the amount of heat removed from the furnace wall cooling equipment at a plurality of positions in the circumferential direction of the blast furnace body for each cooling system, and determines an abnormality in the gas flow of the blast furnace body from the calculated value of the amount of heat removed, The gas flow determination unit When the standard deviation of the heat transfer amount in the circumferential direction exceeds a predetermined threshold value, it is determined that an excessive furnace wall flow has occurred as an abnormality of the gas flow, and among a plurality of positions in the circumferential direction of the blast furnace body, a position where the heat transfer amount exceeds a predetermined first threshold value is determined to be a position where the excessive furnace wall flow has occurred, The blast furnace facility determines that deposits have formed when the amount of heat removal calculated at a plurality of positions in the circumferential direction of the blast furnace body falls below a predetermined second threshold value.

3. a step of calculating, for each of a plurality of cooling systems arranged in the circumferential direction, the amount of heat removed by furnace wall cooling equipment that cools the furnace walls of the blast furnace body at a plurality of positions in the circumferential direction of the blast furnace body in the blast furnace facility using cooling piping that is laid out in the height direction and circumferential direction of the blast furnace body, and determining an abnormality in the gas flow of the blast furnace body from the calculated value of the amount of heat removed; When the gas flow is determined to be abnormal, changing the burden distribution and / or the gas flow rate to the blast furnace body so that the abnormality in the gas flow is eliminated; and The step of determining an abnormality includes: When the standard deviation of the heat transfer amount in the circumferential direction exceeds a predetermined threshold value, it is determined that an excessive furnace wall flow has occurred as an abnormality of the gas flow, and among a plurality of positions in the circumferential direction of the blast furnace body, a position where the heat transfer amount exceeds a predetermined first threshold value is determined to be a position where the excessive furnace wall flow has occurred, The blast furnace operation method determines that deposits have formed when the amount of heat removal calculated at a plurality of positions in the circumferential direction of the blast furnace body is below a predetermined second threshold.

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