WO2024048310A1

WO2024048310A1 - Method for controlling process, method for operating blast furnace, method for manufacturing molten metal, and device for controlling process

Info

Publication number: WO2024048310A1
Application number: PCT/JP2023/029754
Authority: WO
Inventors: 佳也橋本; 稜介益田
Original assignee: Ｊｆｅスチール株式会社
Priority date: 2022-08-31
Filing date: 2023-08-17
Publication date: 2024-03-07
Also published as: JP2024034492A

Abstract

Provided are a method for controlling a process, a method for operating a blast furnace, a method for manufacturing molten metal, and a device for controlling a process that make it possible to highly accurately predict, and control, the state of a blast furnace. In this method for controlling a process: the pig iron production speed, the gas permeability, and the hot metal temperature of a blast furnace are acquired by means of observed values or calculated values; and the pig iron production speed, the gas permeability, and the hot metal temperature are simultaneously controlled on the basis of the acquired observed values or calculated values, as well as a target value for the hot metal temperature (target hot metal temperature), a target value for the pig iron production speed (target pig iron production speed), and a management value for the gas permeability (furnace interior pressure loss upper limit).

Description

Process control method, blast furnace operating method, hot metal production method, and process control device

The present disclosure relates to a process control method, a blast furnace operating method, a hot metal manufacturing method, and a process control device.

Hot metal temperature (HMT) is an important management index in the blast furnace process in the steel industry, and is mainly controlled by adjusting the reducing agent ratio. In recent years, blast furnace operations have been carried out under conditions of low coke ratios and high pulverized coal ratios in order to pursue rationalization of raw material and fuel costs, and the furnace conditions tend to become unstable. Therefore, it is necessary to suppress variations in hot metal temperature.

In addition, the blast furnace process operates with solids filled, so the heat capacity of the entire process is large, and the time constant of response to action is long. Furthermore, it may take several hours, for example, for the raw material charged in the upper part of the furnace to descend to the lower part of the furnace. Therefore, in order to control the hot metal temperature, appropriate operations based on future furnace heat predictions are required.

In the blast furnace process, it is required to control the hot metal temperature and maintain the pig iron production rate (hereinafter referred to as "pig iron making rate") near a target value. To control the pig iron making rate, for example, the air flow rate is manipulated. When controlling the blast flow rate, it is also necessary to take into account the response delay caused by the long time constant of the blast furnace mentioned above. As a blast furnace control method based on prediction, there is a method using a physical model as disclosed in Patent Document 1, for example.

Japanese Patent Application Publication No. 11-335710

Here, if the air flow rate is increased, the pressure loss within the furnace (furnace pressure loss) will increase, and if the pressure loss exceeds the weight of the raw material, there is a risk that blow-through etc. will occur. If blow-by occurs, it will greatly affect the hot metal temperature and pig iron making rate. Therefore, if an abnormality is observed in the ventilation condition such as a pressure drop inside the furnace, it is necessary to stabilize the unloading of raw materials by lowering the air flow rate.

Therefore, in controlling the process in a blast furnace, it is necessary to simultaneously control the hot metal temperature, pig iron making rate, and air permeability, which indicates the ventilation state. The technique of Patent Document 1 controls only the hot metal temperature, and does not propose to control the pig iron making rate and the air permeability at the same time. Conventionally, avoiding blow-throughs and the like has relied heavily on operating techniques (manual operations) based on the experience of skilled operators.

The purpose of the present disclosure, which was made to solve the above problems, is to provide a process control method, a blast furnace operating method, a hot metal manufacturing method, and a process control device that can predict and control the state of a blast furnace with high accuracy. Our goal is to provide the following.

(1) A process control method according to an embodiment of the present disclosure includes:
Obtain the hot metal temperature, pig iron making rate and air permeability of the blast furnace using observed values or calculated values,
Based on the target value of the hot metal temperature, the target value of the pig iron making rate, the management value of the air permeability, and the obtained observed value or calculated value, the hot metal temperature, the pig iron making rate, and the air ventilation are determined. control the degree at the same time.

(2) As an embodiment of the present disclosure, in (1),
a free response prediction step of calculating future predicted values of the hot metal temperature, the pig iron making rate, and the air permeability when the current operating variables are maintained using a physical model capable of calculating the internal state of the blast furnace;
a first operation step of determining the deviation between the predicted values of the hot metal temperature and the iron making speed determined in the free response prediction step and the target values, and determining the amount of manipulation of the manipulated variable to eliminate the deviation; ,
a second operation step of determining manipulated variables of the blast flow rate and coke ratio, which are manipulated variables, based on the predicted value of the air permeability obtained in the free response prediction step and the upper limit value of the air permeability; ,
The first operating step and the second operating step are performed to simultaneously control the hot metal temperature, the iron making rate and the air permeability.

(3) As an embodiment of the present disclosure, in (2),
The manipulated variable in the first operation step is one or more of a blast flow rate, a blast oxygen flow rate, a pulverized coal ratio, a blast moisture content, a blast temperature, a coke ratio, and an oven top pressure.

(4) A blast furnace operating method according to an embodiment of the present disclosure includes:
Operating conditions are changed using the manipulated variables operated by the process control method of any one of (1) to (3).

(5) A method for producing hot metal according to an embodiment of the present disclosure,
Hot metal is produced using the blast furnace operated by the blast furnace operating method of (4).

(6) A process control device according to an embodiment of the present disclosure includes:
Obtain the hot metal temperature, pig iron making rate, and air permeability of the blast furnace using observed values or calculated values, and obtain the target value of the hot metal temperature, the target value of the pig iron making rate, and the control value of the air permeability, and the obtained observation. The method further includes a control unit that simultaneously controls the hot metal temperature, the pig iron making rate, and the air permeability based on the value or the calculated value.

(7) As an embodiment of the present disclosure, in (6),
comprising a storage unit that stores a physical model capable of calculating the internal state of the blast furnace;
The control unit includes:
a hot metal temperature control unit that obtains a target hot metal temperature that is a target value of the hot metal temperature and calculates a manipulated variable of the pulverized coal ratio so that the hot metal temperature becomes the target hot metal temperature;
an iron making speed control unit that acquires a target pig iron making speed that is a target value of the pig iron making speed and calculates a manipulated variable of a blowing flow rate so that the pig iron making speed becomes the target pig iron making speed;
an air permeability control unit that obtains the upper limit of the air permeability and calculates manipulated variables of the air flow rate and coke ratio so that the air permeability does not exceed the upper limit;
The hot metal temperature control section, the pig iron making speed control section, and the air permeability control section are configured to control the future hot metal temperature, the pig iron making speed, and the air permeability when the current operating variables are maintained using the physical model. Find the predicted value of
The hot metal temperature control section and the pig iron making speed control section determine the deviation between the predicted value and the target value of the hot metal temperature and the pig iron making speed, and determine the pulverized coal ratio and the air blowing flow rate for eliminating the deviation. Find the amount of operation of
The air permeability control unit determines the manipulated variables of the ventilation flow rate and coke ratio based on the predicted value of the air permeability and the upper limit value of the air permeability,
The hot metal temperature control section, the pig iron making speed control section, and the air permeability control section simultaneously control the hot metal temperature, the pig iron making speed, and the air permeability.

According to the present disclosure, it is possible to provide a process control method, a blast furnace operating method, a hot metal manufacturing method, and a process control device that can predict and control the state of a blast furnace with high accuracy.

FIG. 1 is a diagram showing manipulated variables and control variables in a blast furnace process. FIG. 2 is a diagram illustrating a process control method according to an embodiment of the present disclosure. FIG. 3 is a diagram showing the relationship between the blast flow rate, coke ratio, pulverized coal ratio, and iron making speed. FIG. 4 is a diagram showing the relationship between the blowing flow rate, the coke ratio, the pulverized coal ratio, and the pressure loss in the furnace. FIG. 5 is a diagram showing input/output information of a physical model used in the present disclosure. FIG. 6 is a diagram showing simulation results when the target pig iron making speed is 6.4 [t/min]. FIG. 7 is a diagram showing simulation results when the target iron making speed is 6.6 [t/min]. FIG. 8 is a diagram illustrating a configuration example of a process control device according to an embodiment of the present disclosure.

Hereinafter, a process control method, a blast furnace operating method, a hot metal manufacturing method, and a process control device according to an embodiment of the present disclosure will be described with reference to the drawings.

Figure 1 shows the basic operating variables and control variables in the blast furnace process (steps in blast furnace operation). A control variable is a variable that must be controlled in operation, but cannot be or is difficult to manipulate directly, and is changed through a correlated manipulated variable. In the operation of a blast furnace, the pulverized coal ratio or coke ratio is mainly manipulated in order to set the hot metal temperature to a target value. In order to maintain good air permeability (air permeability) of the blast furnace, the coke ratio or the air flow rate is mainly controlled. Moreover, in order to set the pig iron making speed to the target value, the air flow rate is mainly manipulated. Here, as the air permeability, in this embodiment, the pressure loss in the furnace, which directly affects the blow-through, is used. Furnace pressure loss is the difference between blast pressure and furnace top pressure (furnace top pressure). In addition to the pressure drop in the furnace, there are various indicators of ventilation, such as ventilation resistance and shaft-to-face differential pressure. Therefore, as the air permeability, another air permeability index may be used instead of the furnace pressure drop, or a combination of a plurality of air permeability indices may be used.

FIG. 2 is a diagram showing the processing of the process control method according to the present embodiment. The process control method according to the present embodiment uses, for example, cascade control described in Reference Document 1 (Japanese Patent No. 7107444). In the cascade control, control for calculating the target pulverized coal ratio (PCR) (hot metal temperature control in Figure 2) and control for calculating the pulverized coal flow rate required for the target PCR (PCR follow-up control in Figure 2) are performed. It is done continuously. Hot metal temperature control can obtain a target hot metal temperature, which is a target value of hot metal temperature (HMT), and calculate a target PCR using a physical model described below. The process control method according to the present embodiment also includes iron making speed control and air permeability control. In pig iron making speed control, a target pig iron making speed which is a target value of pig iron making rate (Production rate: Prod) is acquired, and a manipulated variable of a blowing flow rate (BV) is calculated using a physical model described below. The air permeability control obtains the upper limit of the furnace pressure drop (ΔP), and calculates the manipulated variables of the air flow rate and coke ratio using a physical model to be described later. Here, the actual value (which may be an observed value or a calculated value) in a plant including a blast furnace may be fed back for updating the physical model used in each control. In the example in Figure 2, the actual values of pulverized coal ratio (PCR), hot metal temperature (HMT), pressure drop in the furnace (ΔP), and iron making rate (Prod) are expressed as actual PCR, actual HMT, actual ΔP, and actual Prod, respectively. It is shown. Furthermore, the correspondence between control variables and correlated manipulated variables in the blast furnace process is not limited to that shown in FIGS. 1 and 2. For example, in hot metal temperature control, it is possible to manipulate the air humidity instead of the pulverized coal ratio (PCR). Furthermore, for example, in pig iron making speed control, it is possible to manipulate the blown oxygen flow rate instead of the blown air flow rate.

In this embodiment, in constructing a multivariable control system as shown in FIG. 2, an individual controller (hot metal temperature control , air permeability control, pig iron making speed control). Hot metal temperature is controlled by a cascade control that manipulates pulverized coal ratio (PCR) and pulverized coal flow rate. Air permeability is controlled by manipulating the air flow rate and coke ratio. The pig iron making speed is controlled by manipulating the air flow rate. Here, for example, when the pulverized coal flow rate is manipulated in hot metal temperature control, a change in the pulverized coal flow rate affects the pig iron making rate. This effect is reflected by the physical model in pig iron making speed control and calculated as the manipulated variable of the air blast flow rate, and by reflecting the calculated manipulated variable of the blast flow rate, the iron making speed is maintained near the target value. . In this embodiment, although individual controllers are constructed as described above, it is possible to realize control that takes into account the interference between the respective manipulated variables. In other words, although hot metal temperature control and pig iron making speed control interfere, the control system is constructed as a control system that has a disturbance removal characteristic that absorbs fluctuations caused by the manipulation of the other's manipulated variables by manipulating its own manipulated variables. The impact can be reduced. Furthermore, regarding air permeability, a control system has been constructed that takes into consideration the upper limit of pressure drop within the furnace. In hot metal temperature control and pig iron making speed control, fluctuations due to manipulation of manipulated variables in air permeability control can also be absorbed by manipulation of own manipulated variables due to disturbance removal characteristics.

FIG. 3 is a diagram showing the relationship between blast flow rate (BV), coke ratio (CR), pulverized coal ratio (PCR), and iron making rate (Prod). Moreover, FIG. 4 is a diagram showing the relationship between the blowing flow rate, coke ratio, pulverized coal ratio, and furnace pressure loss (ΔP). The solid line and the broken line indicate the case where the coke ratio and the pulverized coal ratio are replaced under the condition that the reducing agent ratio (the total value of the coke ratio and the pulverized coal ratio) is constant. If the reducing agent ratio is constant, as shown in FIG. 3, the blast flow rate (BV) and the iron making rate (Prod) are in a substantially proportional relationship. In the control simulation of the example shown in FIG. 3, the manipulated variable of the air flow rate was determined according to the deviation between the predicted value of the iron making speed based on the physical model and the target value. Furthermore, as shown in FIG. 4, if the coke ratio (CR) decreases, the furnace pressure drop (ΔP) increases even if the blast flow rate (BV ^* ) is the same. During blast furnace operation, when the pressure drop (ΔP) in the furnace exceeds the upper limit (threshold), the coke ratio is increased and the blast flow rate is simultaneously lowered to stabilize the unloading of raw materials and reduce the pressure drop in the furnace. When the coke ratio is below the upper limit, it is preferable to gradually reduce the coke ratio. In principle, the pressure drop in the furnace is controlled so as not to exceed the upper limit, and when the pressure loss in the furnace is less than the upper limit, it is possible to reduce the cost of operation by gradually reducing the coke ratio. When control is performed in this manner, the value of the pressure drop in the furnace changes near the upper limit.

In general, the process control method according to the present embodiment first obtains the hot metal temperature, pig iron making rate, and air permeability of the blast furnace using observed values or calculated values. Then, the hot metal temperature, the pig iron making speed, and the air permeability are simultaneously controlled based on the target value of the hot metal temperature, the target value of the pig iron making speed, the management value of the air permeability, and the obtained observed value or calculated value. More specifically, the processing of this control method includes the following steps 1 to 3.

First, in step 1, the future hot metal temperature and pig iron production rate are predicted using a physical model. Step 1 is a free-response prediction step in which predicted values of future hot metal temperature, pig iron making rate, and air permeability are determined when the current operating variables are held.

Next, in step 2, the manipulated variables are manipulated so that the predicted values of the hot metal temperature and pig iron making rate in step 1 match the target values. Step 2 is a first operation step in which the deviation between the predicted value and the target value is determined, the amount of operation to eliminate the deviation is determined, and the manipulated variable is adjusted. In this embodiment, the manipulated variables are the pulverized coal ratio and the air flow rate. However, as described above, the correspondence between control variables and correlated manipulated variables in the blast furnace process is not limited to that shown in FIG. 1. The manipulated variables may be, for example, one or more of the following: blast flow rate, blast oxygen flow rate, pulverized coal ratio, blast moisture, blast temperature, coke ratio, and furnace top pressure.

Furthermore, as step 3, based on the predicted value of air permeability in step 1 and the upper limit of air permeability, the manipulated variable of the manipulated variable that has a correlation with air permeability is determined. The upper limit of air permeability is an example of a management value for managing air permeability. Step 3 corresponds to the second operating step. In this embodiment, the air permeability is the pressure drop in the furnace, and if the predicted value of the pressure drop in the furnace exceeds a set upper limit, the ventilation condition is considered to be abnormal, and the operation of reducing the air flow rate and increasing the coke ratio is performed. Execute. When the upper limit is not exceeded, that is, when the predicted value of the pressure drop in the furnace is less than or equal to the upper limit, an operation for reducing the coke ratio is performed. Here, step 2 and step 3 are not executed in a fixed order such that one is executed after the other, but are executed so as to simultaneously control the hot metal temperature, pig iron making rate, and air permeability.

The physical model used in the present disclosure is similar to the model of the method described in Reference 2 (Michiharu Hadano et al., "Study of burning operation using an unsteady blast furnace model", Tetsu-to-Hagane, vol. 68, p. 2369). It is. In other words, it calculates the state inside the blast furnace (furnace) in an unsteady state, which is composed of a group of partial differential equations that take into account physical phenomena such as reduction of ore, heat exchange between ore and coke, and melting of ore. A possible physical model is used. This physical model may be referred to as an unsteady model below.

As shown in Figure 5, among the input variables given to the unsteady model, the main ones that change over time are blast flow rate, blast oxygen flow rate, pulverized coal flow rate, blast moisture, blast temperature, coke ratio, and furnace top pressure. It is. These input variables are operating variables or operating factors of the blast furnace. The blast flow rate, the blast oxygen flow rate, and the pulverized coal flow rate are the flow rates of air, oxygen, and pulverized coal sent to the blast furnace, respectively. The blast humidity is the humidity of the air sent to the blast furnace. The blowing temperature is the temperature of the air sent to the blast furnace. The coke ratio is the coke ratio at the top of the furnace, and is the weight of coke used for one ton of hot metal production.

In addition, the main output variables of the unsteady model are gas utilization rate, solution loss carbon amount (sol loss carbon amount), reducing agent ratio, pig iron making rate, hot metal temperature, and furnace pressure drop. Using the unsteady model, it is possible to calculate the ever-changing hot metal temperature, iron making rate, and furnace pressure drop. Although the time interval of calculation is not particularly limited, it is 30 minutes in this embodiment. In this embodiment, the time difference between "t+1" and "t" in the unsteady model equation described later is 30 minutes.

The unsteady model can be expressed by the following equations (1) and (2).

Here x(t) is a state variable calculated within the unsteady model. State variables include, for example, coke temperature, iron temperature, ore oxidation degree, and raw material fall rate. y(t) is the control variables: hot metal temperature, pig iron making rate, and air permeability (furnace pressure drop). Hot metal temperature, pig iron making rate and air permeability may be distinguished as y ₁ (t), y ₂ (t) and y ₃ (t), respectively. That is, it can be expressed as y(t)=(y ₁ (t), y ₂ (t), y ₃ (t)) ^T. u(t) is the input variable described above, and is a variable that can be operated by the operator who operates the blast furnace. In other words, the input variables are blast flow rate BV (t), blast oxygen flow rate BVO (t), pulverized coal flow rate PCI (t), blast moisture BM (t), blast temperature BT (t), and coke ratio CR (t). , the furnace top pressure TGP(t). It can be expressed as u(t)=(BV(t), BVO(t), PCI(t), BM(t), BT(t), CR(t), TGP(t)) ^T .

First, a predictive calculation of future control variables is performed assuming that the current values of input variables are kept constant. Taking the current time step as t ₀ , future control variables are predicted using equations (3) and (4) below. The response y _f (t) of the control variable determined in this way is called a free response.

Next, in order to eliminate the deviation between the target value and the predicted value of the hot metal temperature, ΔPCR, which is the manipulated variable of the pulverized coal ratio (PCR) [kg/t], is determined by the following equation (5). Here, the manipulated variable represented by ΔPCR is used to calculate an increase/decrease value with respect to the previous manipulated variable (PCR). The meaning of Δ is the same for other manipulated variables.

Here, y _f,1 (t) represents the free response of the hot metal temperature. y _U,1 and y _L,1 are the upper and lower limits of the target hot metal temperature (target range of hot metal temperature), respectively. max (p, q) and min (p, q) are functions that output the larger value and the smaller value of p and q, respectively. From the viewpoint of preventing excessive operation, the operation amount is set to zero as long as the predicted value is within the target range of the hot metal temperature. That is, in Equation (5), if the predicted value of the free response of the hot metal temperature does not exceed the upper limit of the target hot metal temperature, the output of the max function becomes zero. Further, in Equation (5), if the predicted value of the free response of the hot metal temperature does not fall below the lower limit of the target hot metal temperature, the output of the min function becomes zero. S _PCR is the amount of change in hot metal temperature after T ₁ hour when the pulverized coal ratio (PCR) is manipulated by a unit amount (1 [kg/t]). S _PCR can be determined using another physical model or a step response test in actual operation. _T1 is a time step that defines the future time to predict. As an example, T ₁ may be 16, in which case the temperature of the hot metal 8 hours (30 minutes x 16) ahead is predicted. Further, a is a coefficient and a positive number. The control for determining ΔPCR according to equation (5) corresponds to the hot metal temperature control in FIG. 2. As shown in Fig. 2, a target PCR is determined based on ΔPCR determined by hot metal temperature control, and the pulverized coal flow rate (PCI) is adjusted to follow the target PCR by PCR follow-up control as in Reference 1 above. is manipulated.

Further, in order to eliminate the deviation between the target value and the predicted value for the pig iron making speed, ΔBV, which is the manipulated variable of the blast flow rate (BV) [Nm ³ /min], is determined by the following equation (6).

Here, y _f,2 (t) represents the free response of iron making rate. y _U,2 and y _L,2 are the upper limit and lower limit of the target pig iron making speed (target range of pig iron making speed), respectively. From the viewpoint of preventing excessive operation, the operation amount is set to zero as long as the predicted value is within the target range of iron making speed. That is, in Equation (6), if the predicted value of the free response of the pig iron making speed does not exceed the upper limit of the target pig iron making speed, the output of the max function becomes zero. Further, in Equation (6), if the predicted value of the free response of the pig iron making speed does not fall below the lower limit of the target pig iron making speed, the output of the min function becomes zero. S _BV is the amount of change in the iron making speed after T ₂ hours when the blast flow rate (BV) is controlled by a unit amount (1 [Nm ³ /min]). The _SBV can be determined using another physical model or a step response test in actual operation. _T2 is the time step that defines the future time to predict. As an example, T ₂ may be 4, in which case the pig iron making rate for 2 hours (30 minutes x 4) ahead is predicted. Moreover, b is a coefficient and is a positive number. The control for determining ΔBV according to equation (6) corresponds to the iron making speed control in FIG. 2.

Furthermore, according to the predicted value of furnace pressure drop (ΔP) [kPa], which is an example of air permeability, the manipulated variable of coke ratio (CR) [kg/t] is calculated using the following equations (7) and (8). ΔCR, which is ΔCR, and ΔBV, which is an additional manipulated variable of the air flow rate (BV) [Nm ³ /min], are determined. Here, the coke ratio is indicated by the amount of coke input [kg] per ton of hot metal.

Here, y _f,3 (t) represents the free response of pressure drop in the furnace. y _U,3 is the upper limit of the pressure drop in the furnace. As mentioned above, from the viewpoint of reducing operating costs, operations are performed so that the pressure drop in the furnace is close to the upper limit. As an example, _T3 may be 1, in which case the furnace pressure drop is predicted for 30 minutes ahead. Furthermore, c, d, and e are coefficients, each of which is a positive number. Control for determining ΔCR and ΔBV according to equations (7) and (8) corresponds to the air permeability control in FIG.

FIG. 6 is a diagram showing simulation results when the target iron making rate is 6.4 [t/min] using the above process control. That is, in the simulation of FIG. 6, the pulverized coal ratio ( PCR), blast flow rate (BV), and coke ratio (CR) were manipulated. The target hot metal temperature was 1500°C. Further, the upper limit of the pressure drop in the furnace was 100 [kPa]. Regarding hot metal temperature and pig iron making rate, the upper and lower limits of the target range are the same.

For example, from 30 to 70 [hours], the coke ratio (CR) decreases according to the manipulated variable according to the predicted value of the furnace pressure drop (ΔP). In order to compensate for the decrease in heat due to the decrease in coke ratio, the target PCR in hot metal temperature control is increased from 55 to 70 hours. Furthermore, by manipulating the pulverized coal flow rate (PCI) through PCR follow-up control, the actual PCR follows the target PCR. Due to the decrease in the coke ratio (CR) and the increase in the pulverized coal ratio (PCR), the pressure drop (ΔP) in the furnace increases from 30 to 70 [hours]. Here, when the pressure drop in the furnace (ΔP) exceeds the upper limit (target upper limit) at the timing of 72 [hours], the ventilation flow rate (BV) is decreased and the coke ratio (CR) is increased by the ventilation control. ing. Since the pressure drop (ΔP) in the furnace fell below the upper limit between 72 and 75 [hours], an operation was performed to increase the blast flow rate (BV), and as a result, the iron making rate (Prod) was approaching the target value. In this way, the coke ratio (CR) is lowered and the blast flow rate (BV) is adjusted within the range where the pressure drop in the furnace (ΔP) does not exceed the upper limit, and the hot metal temperature (HMT) and iron making rate (Prod) are adjusted. The target hot metal temperature and target pig iron making rate were achieved.

FIG. 7 is a diagram showing simulation results when the target iron making rate is 6.6 [t/min] using the above process control. The conditions except for the target pig iron making speed are the same as in the case of FIG. 6. Similar to the example in Fig. 6, the coke ratio (CR) is lowered and the blast flow rate (BV) is adjusted within the range where the pressure drop (ΔP) in the furnace does not exceed the upper limit, and the hot metal temperature (HMT) and pig iron making are adjusted. Regarding the speed (Prod), the target hot metal temperature and target pig iron making rate were achieved. However, when the target pig iron making speed is increased, a larger blowing flow rate (BV) is required, and therefore the furnace pressure drop (ΔP) tends to reach the upper limit. In order to ensure air permeability, that is, to prevent the furnace pressure drop (ΔP) from exceeding the upper limit, the required coke ratio (CR) increases. In the example of FIG. 6, the coke ratio (CR) was about 305 [kg/t] on average, but in the example of FIG. 7, it increased to 325 [kg/t] on average.

FIG. 8 is a diagram illustrating a configuration example of a process control device 10 according to an embodiment. As shown in FIG. 8, the process control device 10 according to the present embodiment includes a communication section 11, a storage section 12, and a control section 13. The control section 13 includes a hot metal temperature control section 14 , an iron making speed control section 15 , an air permeability control section 16 , and a PCR follow-up control section 17 . The process control device 10 executes the process control method described above. Here, when operating the air flow rate, coke ratio, or pulverized coal ratio, the process control device 10 may display information such as the operating amount on a display unit such as a liquid crystal display.

The communication unit 11 is configured to include a communication module for communicating with the host system. The host system includes a process computer that manages processes in the plant including the blast furnace. The communication unit 11 may include a communication module compatible with mobile communication standards such as 4G (4th Generation) and 5G (5th Generation). The communication unit 11 may include, for example, a communication module compatible with wired or wireless LAN standards. The control unit 13 can obtain information such as a target hot metal temperature, a target iron making rate, and an upper limit of pressure drop in the furnace from the host system via the communication unit 11. Further, the control unit 13 can output information on the manipulated variables that have been operated, that is, the manipulated variables that reflect the calculated manipulated variables, to the host system via the communication unit 11.

The storage unit 12 stores the above physical model. The storage unit 12 also stores programs and data related to control of the blast furnace process. The storage unit 12 may include any storage device such as a semiconductor storage device, an optical storage device, and a magnetic storage device. A semiconductor storage device may include, for example, a semiconductor memory. The storage unit 12 may include multiple types of storage devices.

The control unit 13 controls and manages each functional unit constituting the process control device 10 and the entire process control device 10. The control unit 13 also acquires data used for control. That is, the control unit 13 acquires the hot metal temperature, pig iron making rate, and air permeability of the blast furnace using observed values or calculated values. The control unit 13 is configured to include at least one processor such as a CPU (Central Processing Unit) to control and manage various functions. The control unit 13 may be composed of one processor or a plurality of processors. The processor that constitutes the control section 13 functions as a hot metal temperature control section 14, an ironmaking speed control section 15, an air permeability control section 16, and a PCR follow-up control section 17 by reading out and executing a program from the storage section 12. It's fine.

The hot metal temperature control unit 14 obtains a target hot metal temperature, which is a target value of the hot metal temperature, and calculates the manipulated variable of the pulverized coal ratio so that the hot metal temperature becomes the target hot metal temperature. The hot metal temperature control section 14 is a functional section that executes "hot metal temperature control" in FIG. 2.

The pig iron making speed control unit 15 obtains a target pig iron making speed which is a target value of the pig iron making speed, and calculates the manipulated variable of the air blowing flow rate so that the pig iron making speed becomes the target pig iron making speed. The pig iron making speed control section 15 is a functional section that executes the "iron making speed control" shown in FIG. 2 .

The air permeability control unit 16 obtains the upper limit of the air permeability (furnace pressure loss in this embodiment) and calculates the manipulated variables of the air flow rate and coke ratio so that the air permeability does not exceed the upper limit. The air permeability control section 16 is a functional section that executes the "air permeability control" shown in FIG.

The PCR follow-up control unit 17 acquires the pulverized coal ratio (target PCR), which is a target value determined by the hot metal temperature control unit 14, and controls the pulverized coal flow rate (PCI) to follow the target PCR by PCR follow-up control. Calculate the amount of operation. The PCR follow-up control section 17 is a functional section that executes "PCR follow-up control" in FIG.

The hot metal temperature control section 14, the pig iron making speed control section 15, and the air permeability control section 16 are individual controllers for controlling the hot metal temperature (HMT), the pig iron making speed (Prod), and the pressure drop in the furnace (ΔP). , it is possible to realize control that takes into account the interference between manipulated variables.

To explain using steps 1 to 3 above, the hot metal temperature control section 14, pig iron making speed control section 15, and air permeability control section 16 each execute step 1 (free response prediction step) using a physical model. , find predicted values of hot metal temperature, pig iron making rate and air permeability. The hot metal temperature control section 14 and the pig iron making speed control section 15 each execute step 2 (first operation step) to obtain the operation amounts of the pulverized coal ratio and the air flow rate. The air permeability control unit 16 executes step 3 (second operation step), determines the ventilation state in the furnace based on the predicted value of the air permeability (furnace pressure loss in this embodiment), and determines whether the ventilation state is correct. When it is determined that there is an abnormality, operations are performed to reduce the air flow rate and increase the coke ratio. When determining that the ventilation state is not abnormal, the air permeability control unit 16 executes an operation to reduce the coke ratio. Here, as described above, the hot metal temperature control section 14, pig iron making speed control section 15, and air permeability control section 16, which are constructed as individual controllers, can simultaneously control the hot metal temperature, pig iron making speed, and air permeability. can.

A process control method executed by the process control device 10 may be used as part of the blast furnace operating method. For example, the manipulated variables manipulated in the process control method described above may be used to change operating conditions in the operation of a blast furnace. Moreover, such a method of operating a blast furnace can be carried out as part of a manufacturing method of manufacturing hot metal. In a blast furnace, raw material iron ore is melted and reduced to become pig iron, which is tapped as hot metal, and the blast furnace may be operated according to this operating method.

The process control device 10 may be realized, for example, by a computer separate from the process computer that controls the operation of the blast furnace, or may be realized by the process computer. A computer includes, for example, a memory, a hard disk drive (storage device), a CPU (processing unit), and a display device such as a display. Various functions can be realized by organically cooperating hardware such as a CPU and memory with a program. The storage unit 12 may be realized, for example, by a storage device. The control unit 13 may be realized by, for example, a CPU.

As described above, the process control method, blast furnace operating method, hot metal manufacturing method, and process control device 10 according to the present embodiment operate the manipulated variables based on the hot metal temperature, pig iron making rate, and air permeability with the above configuration. At the same time, the condition of the blast furnace can be predicted and controlled with high precision.

Although the embodiments according to the present disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various changes or modifications based on the present disclosure. It should therefore be noted that these variations or modifications are included within the scope of this disclosure. For example, the functions included in each component or each step can be rearranged to avoid logical contradictions, and multiple components or steps can be combined or divided into one. It is. Embodiments according to the present disclosure can also be realized as a program executed by a processor included in the device or a storage medium recording the program. It is to be understood that these are also encompassed within the scope of the present disclosure.

The configuration of the process control device 10 shown in FIG. 8 is an example. The process control device 10 may not include all of the components shown in FIG. Furthermore, the process control device 10 may include components other than those shown in FIG. For example, the process control device 10 may further include a display section.

10 Process control device 11 Communication section 12 Storage section 13 Control section 14 Hot metal temperature control section 15 Iron making speed control section 16 Air permeability control section 17 PCR follow-up control section

Claims

Obtain the hot metal temperature, pig iron making rate and air permeability of the blast furnace using observed values or calculated values,
Based on the target value of the hot metal temperature, the target value of the pig iron making rate, the management value of the air permeability, and the obtained observed value or calculated value, the hot metal temperature, the pig iron making rate, and the air ventilation are determined. A process control method that simultaneously controls the temperature.
a free response prediction step of calculating future predicted values of the hot metal temperature, the pig iron making rate, and the air permeability when the current operating variables are maintained using a physical model capable of calculating the internal state of the blast furnace;
a first operation step of determining the deviation between the predicted values of the hot metal temperature and the pig iron making speed determined in the free response prediction step and the target values, and determining the amount of manipulation of the manipulated variable to eliminate the deviation; ,
a second operation step of determining manipulated variables of the blast flow rate and coke ratio, which are manipulated variables, based on the predicted value of the air permeability obtained in the free response prediction step and the upper limit value of the air permeability. ,
2. The process control method according to claim 1, wherein the first operating step and the second operating step are performed to simultaneously control the hot metal temperature, the pig iron making rate, and the air permeability.
The manipulated variable in the first operation step is one or more of a blast flow rate, a blast oxygen flow rate, a pulverized coal ratio, a blast humidity, a blast temperature, a coke ratio, and an oven top pressure. How to control the process.
A method for operating a blast furnace, comprising changing operating conditions using manipulated variables operated by the process control method according to any one of claims 1 to 3.
A method for producing hot metal, comprising producing hot metal using the blast furnace operated by the blast furnace operating method according to claim 4.
Obtain the hot metal temperature, pig iron making rate, and air permeability of the blast furnace using observed values or calculated values, and obtain the target value of the hot metal temperature, the target value of the pig iron making rate, and the control value of the air permeability, and the obtained observation. A process control device, comprising: a control unit that simultaneously controls the hot metal temperature, the pig iron making rate, and the air permeability based on the value or the calculated value.
comprising a storage unit that stores a physical model capable of calculating the internal state of the blast furnace;
The control unit includes:
a hot metal temperature control unit that obtains a target hot metal temperature that is a target value of the hot metal temperature and calculates a manipulated variable of the pulverized coal ratio so that the hot metal temperature becomes the target hot metal temperature;
an iron making speed control unit that acquires a target pig iron making speed that is a target value of the pig iron making speed and calculates a manipulated variable of a blowing flow rate so that the pig iron making speed becomes the target pig iron making speed;
an air permeability control unit that obtains the upper limit of the air permeability and calculates manipulated variables of the air flow rate and coke ratio so that the air permeability does not exceed the upper limit;
The hot metal temperature control section, the pig iron making speed control section, and the air permeability control section are configured to control the future hot metal temperature, the pig iron making speed, and the air permeability when the current operating variables are maintained using the physical model. Find the predicted value of
The hot metal temperature control section and the pig iron making speed control section determine the deviation between the predicted value and the target value of the hot metal temperature and the pig iron making speed, and determine the pulverized coal ratio and the air blowing flow rate for eliminating the deviation. Find the amount of operation of
The air permeability control unit determines the manipulated variables of the ventilation flow rate and coke ratio based on the predicted value of the air permeability and the upper limit value of the air permeability,
7. The process control device according to claim 6, wherein the hot metal temperature control section, the pig iron making speed control section, and the air permeability control section simultaneously control the hot metal temperature, the pig iron making speed, and the air permeability.