CN113166821A

CN113166821A - Method and system for turnabout depth control in a blast furnace

Info

Publication number: CN113166821A
Application number: CN201980077381.4A
Authority: CN
Inventors: S·伯恩
Original assignee: Tata Steel Ijmuiden BV
Current assignee: Tata Steel Ijmuiden BV
Priority date: 2018-11-27
Filing date: 2019-11-13
Publication date: 2021-07-23
Also published as: KR20210094519A; JP2022509210A; WO2020108987A1; EP3887553A1

Abstract

The invention relates to a method for turnabout depth control in a blast furnace, said method comprising controlling the flow of hot air through tuyeres by means of a control system, the control system performing turnabout depth measurements through the tuyeres by means of radar sensors, the radar sensors transmitting the turnabout depth measurements to the control system, the control system comparing the turnabout depth measurements with a predetermined turnabout depth, wherein the control system performs the turnabout depth measurements through the tuyeres by means of a plurality of radar sensors distributed over the periphery of the blast furnace.

Description

Method and system for turnabout depth control in a blast furnace

Technical Field

The invention relates to a method for turnabout depth control in a blast furnace, said method comprising controlling the flow of hot air through a tuyere by means of a control system, the control system performing a turnabout depth measurement through the tuyere by means of a radar sensor, the radar sensor sending the turnabout depth measurement to the control system, and the control system comparing the turnabout depth measurement with a predetermined turnabout depth. The invention also relates to a system for depth control of a rotor.

Background

Blast furnaces have been in the past for centuries. However, the conditions inside the blast furnace are harsh, difficult to access and therefore largely unknown. The measurements, in particular in the bottom of the blast furnace, are complicated if not impossible. For the iron works, technical knowledge and experience in operation to finally obtain molten irons having desired characteristics are very important. The measurements in the bottom can only be made on or near the outer edge of the blast furnace. In general, the conditions in the top are more favorable.

A very important process parameter is the size, mainly the depth, of the raceway, which is mainly formed by the flow of hot air (oxygen-enriched air) through the tuyeres. The swirl zone depth is related to the combustion of gas and injected coal in the bottom of the blast furnace and currently it is not possible to accurately measure the swirl zone depth. In the past, temperature sensors and pressure sensors were installed in the walls of blast furnaces, but the measurements did not represent conditions in the bottom of the blast furnace. Furthermore, the distribution of hot blast air and coal over the different tuyeres and the effect on the internal state of the blast furnace bottom are largely unknown. Since the stability and uniformity of the blast furnace are very important for producing stable quality at good speed, iron works are eagerly looking to better control the process in the blast furnace.

It is known that the depth of the raceway depends on the coal injection rate, conversion rate, charge distribution (manner of charging of the blast furnace), gas flow, characteristics of the soft zone, characteristics of the dead zone, tapping operation and coal/hot air flow mixing. It is also believed that the convolution will "collapse" at some point in time and later be reestablished. This is a periodic activity, but it seems to be an unpredictable process.

The small convolute size, having a relatively shallow depth and frequent collapse indicate that the low gas flow leaves the particular convolute and rises into the bottom and further into the shaft of the blast furnace. Increasing the airflow through the tuyere will increase the kinetic energy to the bottom coke, thereby forming a deeper raceway.

CN106191350A describes the use of a radar system to measure the depth of a rotor from measurements over a long period of time. Measurements were taken at individual tuyeres to populate the model with data. However, the proposed method is not accurate enough for process control. Such radar measurement systems are available from local suppliers on the market.

Disclosure of Invention

It is an object of the present invention to provide a better measurement method and system for depth control of a rotor. Another object is to improve the process in the blast furnace by better process control and better stability of the ironmaking process in the blast furnace. Yet another object is to improve blast furnace productivity. Yet another object is to increase the output of the ironmaking process.

To achieve the object of the invention, a method and a system are proposed according to the features of one or more of the appended claims.

Accordingly, the method of the invention also comprises a control system which performs a raceway depth measurement through a plurality of tuyeres by means of a plurality of radar sensors distributed over the circumference of the blast furnace. The measurement of the depth of the convolute zone by means of radar sensors through different tuyeres shows that the depth of the convolute zone varies greatly over the circumference of the blast furnace. For a stable process, a uniform depth of the convolute region over the circumference of the blast furnace is preferred. Since the blast furnace is equipped with a plurality of tuyeres distributed over the circumference of the blast furnace, a plurality of radar sensors distributed over the circumference of the blast furnace enables a better control of the hot air flow through said plurality of tuyeres. Each radar sensor may be dedicated to a particular tuyere, but for improved stability and accuracy, multiple radar sensors may be dedicated to one tuyere.

In a preferred embodiment, the control system controls the flow of hot wind through the plurality of tuyeres by comparing a raceway depth measurement to a predetermined raceway depth for the plurality of tuyeres in order to achieve a uniform raceway depth over the circumference of the blast furnace. An advantage of controlling the flow of hot air through a plurality of tuyeres is that the control is performed in a synchronized manner. Thus, individual differences between the rotor depth measurement and the predetermined rotor depth over a plurality of tuyeres can be controlled. The hot air flow over the periphery of the blast furnace is controlled by a control system by valves located at the air ports. The valve can be opened or closed in a manner known per se. The predetermined rotor depth is a depth set on the basis of historical measurements, and the results of these measurements may vary over time, under certain conditions, said predetermined rotor depth also being related to a specific blast furnace.

In the method, a plurality of radar sensors, preferably with a small opening angle, are arranged such that they measure through one or more tuyeres distributed over the circumference of the blast furnace. The radar sensor collects data of the depth of the rotor and sends the data to the control system. The data is then processed by the control system. The predetermined range of the rotor depth may be set as a rotor depth range by defining a minimum rotor depth and a maximum rotor depth between which the rotor depth is considered to have an optimal value. Furthermore, it is considered advantageous that the depth of the rotor is uniform over the circumference of the blast furnace in order to obtain maximum stability, throughput and speed.

In a preferred embodiment, the control system reduces the flow of hot air through the one or more tuyeres when the rotor depth measurement has a value higher than the predetermined rotor depth, and increases the flow of hot air through the one or more tuyeres when the rotor depth measurement has a value lower than the predetermined rotor depth. Generally, the higher the hot air flow, the deeper the raceway depth will be. Thus, the hot wind flow is directly related to the depth of the rotor. The predetermined raceway depth is an ideal case set for an optimal process in the blast furnace.

In another preferred embodiment, the control system controls the flow of hot wind through one or more tuyeres in a manner that combines a rotor depth measurement with at least one other blast furnace control measurement sent to the control system selected from the group consisting of top gas temperature, top gas composition, infrared and/or visible light images, spectroscopic measurements, amount of carbon monoxide and/or carbon dioxide, furnace wall temperature and pressure measurements. Preferably, at least one other measurement sent to the control system is combined with the rotor depth measurement. In this way, the process conditions inside the blast furnace can be more fully controlled. The control system constantly collects data from a plurality of sensors. By combining the measurements, a more optimal blast furnace operation can be established based on the combination of data.

In yet another preferred embodiment, the control system controls the flow of hot air via one or more combinations of two or more tuyeres. It is preferred to combine at least two tuyeres to have a greater impact on the process within the blast furnace. Each individual tuyere also has a certain influence on the other tuyeres and in this way the control can be further enhanced. The combination may be selected based on the measured depth of the convolution. It may be required that the combination of at least two tuyeres is formed by two or more tuyeres adjacent to each other. But it may also be required to combine at least two tuyeres opposite to each other. Depending on the specific processing conditions inside the blast furnace, and the control system can set the desired combination according to measurements of different convolution depths on the periphery of the blast furnace. Obviously, the number of combinations of tuyeres is almost unlimited, as a combination of tuyeres may consist of two, three, four or even more tuyeres, and the combinations may be provided on the periphery of the blast furnace adjacent to each other, opposite or via another pattern.

In another preferred embodiment, the control system provides a visual display of the rotor depth on the periphery of the blast furnace. In this way, the process operator is provided with an immediate visual overview of the turnarounds depth on the periphery of the blast furnace. It is known that visual displays are advantageous over data lists because visual displays are easier to understand. If the system is not automatically controllable, it is obvious to the process operator where to increase or decrease the hot wind flow if necessary. The visual display is shown on the process control screen.

In yet another preferred embodiment, the plurality of sensors send the rotor depth measurements to the control system in a continuous manner. The flow of hot air through each tuyere is preferably controlled individually but also continuously. Controlling each tuyere individually ensures that each individual tuyere can be set to a hot blast value independently of the other tuyeres. Since modern blast furnaces produce iron in a continuous manner, this means that measurements are preferably also made in a continuous manner to maintain close to the predetermined turning zone depth. This also means that the measurements are made in real time and immediate control and uniformity is ensured without delay. In this way, rapid changes in the depth of the convolution can also be measured. Of course, the time interval may be set according to necessity and stability of the conditions inside the blast furnace. This provides greater flexibility to the method and system.

Drawings

The invention is further elucidated below with reference to the appended drawings of exemplary embodiments according to the invention, which embodiments do not limit the appended claims.

In the figure:

FIG. 1 shows a sectional view of a blast furnace;

FIG. 2 shows a part of the section of FIG. 1 in an enlarged view;

FIG. 3 shows the system in operation;

FIG. 4 shows a top view of the system in operation;

FIG. 5 shows a measurement of the depth of the convolute over the periphery of the blast furnace under non-optimal conditions;

FIG. 6 shows a measurement of the depth of the rotor at the periphery of the blast furnace under optimum conditions;

fig. 7 shows a flow chart of the process.

Whenever the same reference numerals are used throughout the drawings, these numerals refer to the same parts.

Detailed Description

Fig. 1 shows a sectional view of a blast furnace (1) with a shaft (2), a reflow zone (3), a drip zone (4) and a dead-mass zone (5). A convolution (6) is shown in the drip zone (4), said convolution having a convolution depth (R), which is more clearly shown in fig. 2.

Fig. 2 shows the convolution depth (R) of the convolution region (6). The convolution area is formed in the blast furnace bottom coke in front of the bird nest area (7) by hot air flow (8) passing through the tuyere (9). The position of the tuyere (9) is shown and it is installed through an opening in the wall (14) of the blast furnace (1). The arrows in the figure show the flow of hot air (8) through the tuyeres (9) into the bottom coke in front of the bird nest area (7) of the drip zone (4), thus forming a raceway (6) with a raceway depth (R).

In fig. 3, the annular air duct (10) is shown connected to the tuyere (9). An annular duct (10) extends around the periphery of the blast furnace and provides a hot air flow (8) to the tuyeres (9) via valves (18). The coal injection lance (11) is also part of the arrangement. Also shown is a radar sensor (15) configured to measure through a tuyere (9) of the blast furnace (1). The radar sensor (15) sends its signal through the tuyere (9) and measures the depth (R) of the raceway (6) formed. The radar sensor (15) then sends the rotor depth measurement (RM) to the control system (16), shown more clearly schematically in fig. 7.

Fig. 4 shows an example of a top view of the radar sensor (15) mounted at the tuyere (9). For the sake of clarity, only three radar sensors (15) are shown, but more radar sensors (15) may be installed at a plurality of tuyeres (9) distributed over the circumference of the blast furnace (1). The convolution (6) with convolution depth (R) is clearly shown. Depending on the design of the blast furnace (1), other configurations of the radar sensor (15) can be selected. For clarity, the wall (14) is also shown.

Fig. 5 shows a visual display (17) of the raceway depth (R) at a plurality of tuyeres (9) distributed over the circumference of the blast furnace (1). Each point represents a convolution depth (R) and in this visual display 30 tuyeres (9) with 30 convolution depths (R) are shown. This is an example of a curve in a non-optimal blast furnace process. As shown, there are a plurality of convolution depths (R) on the periphery of the blast furnace (1), which are not uniformly distributed over the periphery of the blast furnace (1).

The optimal case is depicted in fig. 6. All the convolution depths (R) formed by the hot blast flow (8) through the tuyeres (9) (as in fig. 5, also 30 tuyeres (9) have 30 convolution depths (R)) have the same value, thus achieving a uniform convolution depth (R) over the circumference of the blast furnace (1).

Fig. 7 shows a flow chart of the method. The plurality of radar sensors (15) perform a raceway depth measurement (RM) through a plurality of tuyeres (9) distributed over the circumference of the blast furnace (1). The convolution depth measurement (RM) is the result of a signal from the convolution depth (R) of a particular convolution (6). This rotor depth measurement (RM) is then sent by the radar sensor (15) to the control system (16). The control system controls the process of the blast furnace (1) by controlling the flow of hot air (8) through a plurality of tuyeres (9). The control system (16) compares the at least one convolution depth measurement (RM) with a predetermined convolution depth (RP). The predetermined rotor depth may be set to a desired value and is based primarily on historical data stored in the control system. The control system controls the hot blast flows (8) through the plurality of tuyeres (9) in dependence on the difference between the raceway depth measurement (RM) and the predetermined raceway depth (RP) in order to achieve a uniform raceway depth (R) over the circumference of the blast furnace (1).

The control system (16) is also adapted to collect data from a plurality of other sensors, such as top gas temperature, top gas composition, infrared and/or visible light imaging, spectroscopic measurements, amounts of carbon monoxide and/or carbon dioxide, furnace wall temperature and pressure measurements. These other measurements are denoted by (M). The control system (16) is adapted to not only collect but also analyze further measurement data (M), combine said further measurement data with the rotor depth measurement (RM), and then adjust the hot air flow (8) through the tuyere (9) accordingly. It is also shown that a visual display of the rotor depth (R) can be provided on the process control screen (17) in order to enable the process operator to quickly and informationally view the rotor depth (R) inside the blast furnace (1). These visual displays are more clearly shown in fig. 5 and 6.

Although the invention has been discussed above with reference to exemplary embodiments thereof, the invention is not limited to these specific embodiments, which can be varied in many ways without departing from the invention. Therefore, the discussed exemplary embodiments should not be used to interpret the appended claims strictly in light thereof. Rather, these embodiments are intended only to interpret the words of the appended claims and are not intended to limit the claims to these exemplary embodiments. The scope of protection of the invention should therefore be determined solely by the appended claims, in which possible ambiguities in the wording of the claims should be interpreted using these exemplary embodiments.

Claims

1. A method for turnabout depth (R) control in a blast furnace (1), the method comprising controlling a flow of hot blast (8) through a tuyere (9) by means of a control system (16), the control system (16) performing a turnabout depth measurement (RM) through the tuyere (9) by means of radar sensors (15), the radar sensors (15) sending the turnabout depth measurement (RM) to the control system (16), the control system (16) comparing the turnabout depth measurement (RM) with a predetermined turnabout depth (RP), characterized in that the control system (16) performs the turnabout depth measurement (RM) through a plurality of tuyeres (9) by means of a plurality of radar sensors (15) distributed over the circumference of the blast furnace (1).

2. Method for turnabout depth (R) control according to claim 1, characterized in that the control system (16) controls the hot blast flow (8) through the plurality of tuyeres (9) by comparing the turnabout depth measurement (RM) with the predetermined turnabout depth (RP) for the plurality of tuyeres (9) in order to achieve a uniform turnabout depth (R) over the circumference of the blast furnace (1).

3. Method for a raceway depth (R) control according to claim 1 or 2, characterized in that the control system (16) decreases the hot blast flow (8) through one or more tuyeres (9) when the raceway depth measurement (RM) has a value higher than the predetermined raceway depth (RP), and increases the hot blast flow (8) through the one or more tuyeres (9) when the raceway depth measurement (RM) has a value lower than the predetermined raceway depth (RP).

4. Method for the cyclotron depth (R) control according to any one of claims 1 to 3, wherein the control system (16) controls the flow of hot blast air (8) through the one or more tuyeres (9) in such a way that the cyclotron depth measurement (RM) is combined with at least one other blast furnace control measurement (M) sent to the control system (16), selected from the group consisting of top gas temperature, top gas composition, infrared and/or visible light images, spectral measurements, carbon monoxide and/or carbon dioxide amounts, furnace wall temperature and pressure measurements.

5. Method for rotor depth (R) control according to any of claims 1 to 4, characterized in that the control system (16) controls the hot wind flow (8) via one or more combinations of two or more tuyeres (9).

6. Method for turnstile depth (R) control according to any of claims 1 to 5, characterized in, that the control system (16) provides a visual display (17) of the turnstile depth (R) on the periphery of the blast furnace (1).

7. Method for the control of the depth of a raceway (R) according to any of claims 1 to 6, characterized in that the plurality of radar sensors (15) send the raceway depth measurements (RM) to the control system (16) in a continuous manner.

8. A system for turnabout depth (R) control in a blast furnace (1), the system comprising a control system (16) for controlling a flow (8) of hot blast through tuyeres (9), the control system (16) having a radar sensor (15) for performing a turnabout depth measurement (RM) through the tuyeres (9), the radar sensor (15) being arranged to send the turnabout depth measurement (RM) to the control system (16), the control system (16) being arranged to compare the turnabout depth measurement (RM) with a predetermined turnabout depth (RP), characterized in that the control system (16) is arranged to perform the turnabout depth measurement (RM) through a plurality of tuyeres (9) by means of a plurality of radar sensors (15) distributed over the circumference of the blast furnace (1).

9. The system for turnabout depth (R) control according to claim 8, characterized in that the control system (16) is arranged to control the hot blast flow (8) through the plurality of tuyeres (9) by comparing the turnabout depth measurement (RM) with the predetermined turnabout depth (RP) for the plurality of tuyeres (9) in order to achieve a uniform turnabout depth (R) over the circumference of the blast furnace (1).

10. The system for a raceway depth (R) control according to claim 8 or 9, characterized in that the control system (16) is arranged to decrease the flow (8) of hot air through one or more tuyeres (9) when the raceway depth measurement (RM) has a value higher than the predetermined raceway depth (RP), and to increase the flow (8) of hot air through the one or more tuyeres (9) when the raceway depth measurement (RM) has a value lower than the predetermined raceway depth (RP).

11. The system for turnabout depth (R) control according to any of the claims 8 to 10, characterized in that the control system (16) is arranged to control the flow of hot blast air (8) through the tuyere or tuyeres (9) in such a way that the turnabout depth measurement (RM) is combined with at least one other blast furnace control measurement (M) sent to the control system (16) selected from the group consisting of top gas temperature, top gas composition, infrared and/or visible light images, spectral measurements, amount of carbon monoxide and/or carbon dioxide, furnace wall temperature and pressure measurements.

12. System for turnabout depth (R) control according to any of claims 8-11, characterized in that the control system (16) is arranged to control the hot wind flow (8) via one or more combinations of two or more tuyeres (9).

13. System for turnstile depth (R) control according to any one of claims 8 to 12, characterized in that the control system (16) is arranged to provide a visual display (17) of the turnstile depth (R) on the periphery of the blast furnace (1).

14. System for rotor depth (R) control according to any of the claims 8-13, characterized in that the plurality of radar sensors (15) are arranged to send the rotor depth measurements (RM) to the control system (16) in a continuous manner.