EP2955236A1 - Method and apparatus for controlling the fill height of a raw material in a blast furnace - Google Patents

Abstract

The invention relates to a method for controlling the filling level (h) of a raw material (9) in a blast furnace (1), wherein the blast furnace (1) has a feed area for further raw material (9) comprising a chute system, wherein the chute system is one vertical Axially rotating chute (2a) which produces an annular application of the further raw material (9) to the raw material (9) already present in the blast furnace (1), and wherein the chute system comprises a raw material flow flap (7, 7 ') as a function of a flap position causes a constant inflow of further raw material (9) to the blast furnace (1). According to the invention, an angular velocity (ε) of the rotating chute (2a) is changed as a function of a locally present filling level (h) of the raw material (9) in the blast furnace (1).

Description

The invention relates to a method for controlling the filling level of a raw material in a blast furnace, wherein the blast furnace has a feed area for further raw material comprising a chute system, wherein the chute system comprises a chute rotating about a vertical axis, which comprises an annular application of the further raw material to the in the Blast furnace already existing raw material produced, and wherein the chute system comprises a raw material flow flap, which causes a function of a flap position a constant inflow of additional raw material to the blast furnace. The invention further relates to a control system for a balancing system of a blast furnace, the metering system comprising a chute system with a chute rotationally driven about a vertical axis for annularly charging further raw material to raw material already present in the blast furnace, the chute further comprising a raw material flow flap with adjustable Flap position includes, and wherein at least one unit for determining a locally present level of the raw material in the blast furnace is present. The invention further relates to an aerating system for a blast furnace, comprising a chute system having a chute rotating about a vertical axis for annularly depositing further raw material on raw material already present in the blast furnace, the chute further comprising a raw material flow flap with adjustable flap position, and wherein at least one unit for determining the locally present filling level of the raw material in the blast furnace is present. Finally, the invention relates to a blast furnace with such a Belichtungsanlage.

It is well-known that for filling a blast furnace with raw material mostly gassing systems with chute systems be used. Thus, the German patent application no. 2 035 458 a furnishing device for a shaft furnace, in particular a blast furnace, with a chute system.

The DE 601 02 714 T2 describes a device for distributing bulk material as part of a Belichtungsanlage for a blast furnace. The device comprises a rotatable chute with an adjustable inclination angle.

In the operation of a blast furnace, it is known that sometimes very different surface profiles occur at the upper boundary surface of the raw material introduced into the blast furnace from above in the area of the metering installation. The raw material suffers locally due to locally different processes in the blast furnace, while other areas of the raw material hardly yield and remain as an elevation. The causes of this behavior are uneven tapping of the blast furnace, unevenness in the raw material, collapse, slippage or compression of the raw material, a locally accelerated reduction and melting behavior of the raw material or the like. supposed. This results in differences in the local levels in the blast furnace, which in turn also contribute to the fact that the reduction and smelting process in the blast furnace does not run locally evenly or symmetrically. The upper boundary surface of the raw material, to which raw material is repeatedly fed from above via the delivery system, is - as seen from above in the direction of the longitudinal axis of the blast furnace - conceptually divided into circle segments. In the circular segments, where the reduction and smelting process presumably takes place more quickly, indentations, ie below-average levels of raw material in the blast furnace, form.

The raw material is applied in multiple layers, these layers usually having a thickness in the range of 0.2 to 0.8 m. The chute alternately carries either ore, sinter or pellets or coke. Also the position the task of different materials may vary. Thus coarse coke can preferably be introduced in the middle region of the blast furnace, that is to say near the longitudinal axis of the blast furnace, while fine ores are introduced in the outer region, that is to say in regions with the largest possible distance from the longitudinal axis of the blast furnace. This procedure serves to protect an outdoor area of the blast furnace from overheating and to adjust the air resistance of the blast furnace.

It has already been tried in different ways to control the level in the blast furnace to form the upper interface as flat as possible and thus to achieve a uniform level in all circle segments. In this case, a regulation of the filling level on the discharge amount of the chute, which can be adjusted by a different flap position of the raw material flow flap, has proved to be less practicable. The reasons for this are the often lacking adjustment speed and dynamics of the raw material flow damper or limitations in the operability of conventional raw material flow control valves. For example, raw material flow flaps are in use that can not be closed during flow of the raw material.

Furthermore, it is known to provide the circular segments, in which indentations are determined, specifically with raw material. If it is determined by a unit for determining a locally present level of filling of the raw material in the blast furnace that a recess with a below-average filling level of the raw material has formed in a circular segment, the chute is controlled such that it only uses the rocking material in a reciprocating motion to the affected circle segment. About the inclination angle of the chute is still controlled, at which distance from the longitudinal axis of the blast furnace, the raw material is to be deposited annularly. In a unit for determining a locally present filling level may be the operating personnel and / or a sensor arrangement, for example with a optical sensor, act. Common is the use of infrared cameras, with which the upper interface of the raw material is recorded. In detected areas with elevated temperatures is assumed that a recess with below average level of the raw material, while in detected areas with low temperatures is assumed by a survey with above-average level of the raw material.

In order to understand the disadvantages of this method, the operation of the entire blast furnace plant including the bunker facilities for the assembly of the raw material and the transport system for the raw material in the direction of the metering system must be considered. Thus, usually between the bunkers and the Belichtungsanlage in the transport system constantly about 4 to 6 different raw material batches on the road, which differ in their material composition. About 20 to 26 batches are mixed per hour. However, due to the different material compositions and / or the batch size, not every batch is suitable for filling in a resulting indentation. Thus, different batches are put together containing either ore, sinter or pellets or coke. The assembly of a single suitable special batch requires separate intervention in the batch creation process and usually takes about 15 minutes. A shortening of this time is usually only possible if structural changes to the blast furnace system are made with immense effort, eg an installation of additional material bunkers, conveyor belts, etc. takes place. Therefore, usually no special batch is put together, but filled the next available raw material batch in the indentation. The normal chaff operation is interrupted, which leads to losses in the productivity of the plant and more operator errors can occur by the operator of the blast furnace. Incorrect positioning of the chute in an incorrectly selected circle segment can, in the case of such an incorrect operation, still further increase the level differences in the blast furnace. If a batch that is too large is filled into a recess, a mound is formed instead of the recess, which is just as undesirable.

The object of the invention is to provide an improved method for controlling the level of a raw material in a blast furnace. Furthermore, it is an object of the invention to provide a suitable control system.

The object is for the method for controlling the filling level of a raw material in a blast furnace, wherein the blast furnace has a feed area for further raw material comprising a chute system, wherein the chute system comprises a chute rotating about a vertical axis, the an annular application of the further raw material on the produced in the blast furnace already existing raw material, and wherein the chute system has a raw material flow flap, which causes a constant inflow of additional raw material to the blast furnace, depending on a flap position, achieved by an angular velocity of the rotating chute in response to a locally present level of the raw material is changed in the blast furnace.

The chute is therefore operated so that circular segments with indentations and below average level of raw material are passed through slower than circular segments with elevations and above average level of raw material. Due to the fact that in such a procedure, the chute longer in a circular segment with a recess remains, more raw material is stored in this circle segment and thus filled the indentation. In this case, the next available raw material batch can be used in a simple manner. The control interventions to provide the required angular velocity per circle segment can be done manually or automatically.

The inventive method has the advantage that no special batches are required and no interruption of the normal charging operation must be made. The productivity of the blast furnace plant is maintained throughout.

Each raw material batch is deposited in the blast furnace all over the upper boundary of the raw material, but in different amounts. The Gasdurchströmbarkeit the filling and thus the temperature of the blast furnace are made uniform, so that the risk of caking of the raw material is reduced to the shell of the blast furnace.

It is also feasible to introduce a targeted asymmetry in the filling level of the blast furnace, ie in the area of the upper boundary surface, e.g. if a blast furnace in a certain circle segment reproducibly tends to form indentations. This may for example be the case above the tapping openings of the blast furnace. In such a case, depositing more ore, sinter or pellets above the tapping openings and more coke on the same level between the tapping openings leads to a significant equalization of the temperature distribution in the blast furnace.

It has proven useful if, furthermore, an inclination angle of the chute is changed as a function of the locally present filling level of the raw material in the blast furnace. In order to indentations that are present locally and only at certain distances from the longitudinal axis of the blast furnace, can also selectively fill.

The angular velocity of the chute in areas of the blast furnace with locally below average filling height is preferably set lower than in areas with locally average or above-average filling level.

The angular velocity of the chute in areas of the blast furnace with local above-average filling level is particular is set higher than in areas with locally average or below average fill levels.

These measures reliably compensate for unevenness in the upper boundary of the raw material in the blast furnace and reliably equalize the reduction and smelting process in the blast furnace.

The object is achieved for the control system for a Belichtungsanlage a blast furnace, wherein the Beschichtungsanlage comprises a chute system with a rotatably driven about a vertical axis chute for annular application of additional raw material on existing in the blast furnace raw material, the chute system further with a raw material flow flap adjustable flap position, wherein at least one unit for determining a locally present level of filling of the raw material in the blast furnace by the control system is adapted to change an angular velocity of the rotating chute depending on the determined locally present level of the raw material in the blast furnace.

The control system according to the invention has the advantage that no special batches are required and no interruption of the normal charging operation must take place. The productivity of the blast furnace plant is maintained throughout.

The control system is preferably further configured to change a slope angle of the chute in dependence on the determined locally present filling level of the raw material in the blast furnace.

If it is detected by the unit for determining a locally present filling level of the raw material in the blast furnace that there is a recess in the upper boundary surface of the raw material, the regulating interventions can be used to provide the required angular velocity per circular segment and / or required tilt angle within a circle segment manually by the operator or automatically.

An aerator for a blast furnace is particularly preferred comprising a chute system having a chute rotatably driven about a vertical axis for annularly charging further raw material to raw material already present in the blast furnace, the chute system further comprising a raw material flow flap with adjustable flap position, and wherein at least a unit for determining the locally present filling level of the raw material is present in the blast furnace, with furthermore a control system according to the invention.

A blast furnace with such a treatment plant has proved to be advantageous.

FIG 1

eine schematische Darstellung einer Hochofenanlage;

FIG 2

eine schematische Draufsicht auf die obere Grenzfläche des Rohmaterials in einem Hochofen;

FIG 3

ein Diagramm betreffend FIG 1 mit den eingestellten Winkelgeschwindigkeiten der Schurre bei unterschiedlichen Neigungswinkeln der Schurre;

FIG 4

ein erstes mögliches Fahrprogramm für eine Schurre;

FIG 5

ein zweites mögliches Fahrprogramm für eine Schurre;

FIG 6

ein drittes mögliches Fahrprogramm für eine Schurre;

FIG 7

ein viertes mögliches Fahrprogramm für eine Schurre;

FIG 8

ein fünftes mögliches Fahrprogramm für eine Schurre; und

FIG 9

eine schematische Darstellung eines Regelungssystems.

The FIGS. 1 to 9 The method according to the invention and the control system according to the invention are intended to be illustrated by way of example. So shows:

FIG. 1

a schematic representation of a blast furnace system;

FIG. 2

a schematic plan view of the upper boundary surface of the raw material in a blast furnace;

FIG. 3

a diagram regarding FIG. 1 with the set angular speeds of the chute at different angles of inclination of the chute;

FIG. 4

a first possible driving program for a chute;

FIG. 5

a second possible driving program for a chute;

FIG. 6

a third possible driving program for a chute;

FIG. 7

a fourth possible driving program for a chute;

FIG. 8

a fifth possible driving program for a chute; and

FIG. 9

a schematic representation of a control system.

FIG. 1 1 shows a schematic representation of a blast furnace installation comprising a blast furnace 1, a metering installation 2, a bunker installation 3 with a plurality of material bins 4 containing different starting materials for assembling different raw material batches 9a, 9b, and a transport system 5 for transporting the raw material batches 9a, 9b from the bunker installation 3 to the treatment plant 2. The blast furnace 1 has a shell 1a and a longitudinal axis 1b. The metering system 2 comprises a chute system with a chute 2a, a drive 2b (not shown here in detail) (cf. FIG. 9 The drive 2b is set up, on the one hand a rotation of the chute 2a about a vertical axis, here the longitudinal axis 1b of the blast furnace 1, in an adjustable Angle velocity ω effect and on the other hand to adjust an inclination angle γ of the chute 2a. On an upper boundary surface 9 'of the already filled into the blast furnace 1 raw material 9 2a further raw material batches 9a, 9b abandoned by means of the chute 2a. The locally resulting level h of the raw material 9 in the blast furnace 1 can be detected by a unit 11, here in the form of infrared cameras, with areas of high infrared radiation as indentations 10 in the upper boundary surface 9 'with below average level h and areas with low infrared radiation Elevations in the upper boundary 9 'are rated above average level h.

FIG. 2 Now shows a schematic plan view of the upper boundary surface 9 'of the raw material 9 in a blast furnace 1 according to FIG. 1 in section A-A '. Same reference numerals as in FIG. 1 identify similar elements. The upper interface 9 'is divided into circle segments K1 to K8, each one Circle segment K1 to K8 is assigned to a certain angular range at the formed by the shell 1a of the blast furnace 1 circle. Thus, the angular segment K1 is assigned an angular range of 0 to 45 °, the circular segment K2 an angular range of 45 to 90 ° and so on. The size of the angles φ of the circle segments will depend essentially on the dimensions of the blast furnace 1 and the specifications of the drive 2b of the chute 2a and is therefore variable within wide limits. Here, by means of unit 11 (cf. FIG. 1 ) a recess 10 is detected, which is located in the edge region of the circle segments K4 and K5.

To the indentation 10 with the next raw material batch 9a (see FIG. 1 ), the chute 2a becomes in accordance with FIG. 3 driven.

FIG. 3 shows a diagram concerning FIG. 2 with the set angular velocities ω of the chute 2a at two different angles of inclination γ of the chute 2a. In this case, the angular velocity ω (in rad / s) of the chute 2a is plotted over an angle φ (in radians) in which the chute 2a is located. Here, the chute 2a is guided here on two tracks B2 and B2 (see FIG. 2 ), which result from the adjustment of the two different inclination angles γ. Here is to fill the indentation 10 (see FIG. 2 ) moves the chute 2a on the path B1 and the angular velocity ω _{1 of} the chute 2a in the region of the circle segments K4 and K5, corresponding to an angular range of φ ≈ 155 to φ ≈ 205 °, lowered to a lower angular velocity ω _v . As a result, in the region of the indentation 10, more raw material 9 of the raw material charge 9a is deposited. After passing through this angular range, the angular velocity is raised again to the original value ω ₁ . Subsequently, the chute 2a is moved on the web B2 moves with a uniform angular velocity ω ₂ , since there is no indentation 10 on the web B2. Thus, the raw material batch 9a is distributed over the entire upper boundary surface 9 ', but applied locally in different layer thickness.

This leads to a compensation of the indentation 10 and to the formation of a uniformly flat upper boundary surface 9 '.

The FIGS. 4 to 8 now show possible driving programs for a chute 2a. Same reference numerals as in the FIGS. 1 to 3 identify similar elements. In each case, four different angles of inclination γ of the chute 2a are set, thereby traversing four lanes B1 to B4. In the area of the indentation 10, the angular velocity ω of the chute 2a (marked with thick bars on the tracks B1 to B4) is slowed down in each case.

FIG. 9 shows a schematic representation of a control system 100 for the conditioning system 2 of the blast furnace 1 according to FIG. 1 , Same reference numerals as in the FIGS. 1 to 8 identify similar elements. The radiation images acquired by means of the unit 11 in the form of an infrared camera, via which a local filling level h of the blast furnace 1 is determined, are transferred to a computing unit 101, which comprises a travel program for the chute 2a, including specifications for the angular velocity ω as a function of the angle φ, in which the chute 2 is located and specifications concerning an inclination angle γ of the chute 2a for setting abzufahrenden paths B1 to B _x provides. The calculated driving program is transmitted to a control unit 102, which in turn regulates the drive 2b of the chute 2a and a respective drive 7a of the raw material flow flaps 7, 7 'according to the driving program. The task of raw material 9 achieved on the upper boundary surface 9 'due to the set flap position and the movement profile of the chute 2a with simultaneous filling of indentations 10 generates a modified radiation image which is detected again by the unit 11 and indicates a new local filling height h. As an alternative to an automatic transfer of the local filling heights h to the arithmetic unit 101, the radiation images can also be evaluated by the operator of the blast furnace system and the desired driving program can be manually entered into the arithmetic unit 101 via an input unit 103.

The in the FIGS. 1 to 9 shown embodiments of the invention are not limited to the design of the blast furnace system or Belichtungsanlage shown here.

Claims (8)

Method for regulating the filling level (h) of a raw material (9) in a blast furnace (1), the blast furnace (1) having a feed area for further raw material (9) comprising a chute system, the chute system comprising a chute rotating about a vertical axis (9) 2a), which produces an annular application of the further raw material (9) to the raw material (9) already present in the blast furnace (1), and wherein the chute system comprises a raw material flow flap (7, 7 ') which is dependent on a flap position a constant inflow of further raw material (9) to the blast furnace (1) causes, characterized in that an angular velocity (ω) of the rotating chute (2a) in dependence on a locally present filling level (h) of the raw material (9) in the blast furnace (1 ) is changed. Method according to claim 1,
characterized in that further an angle of inclination (γ) of the chute (2a) in dependence on the locally present filling level (h) of the raw material (9) in the blast furnace (1) is changed. A method according to claim 1 or claim 2,
characterized in that the angular velocity (ω) of the chute (2a) in areas of the blast furnace (1) with locally below average filling level (h) is set lower than in areas with locally average or above average filling level (h). Method according to one of claims 1 to 3,
characterized in that the angular velocity (ω) of the chute (2a) is set higher in areas of the blast furnace (1) with locally above-average filling level (h) than in areas with locally average or below average filling level (h). A control system (100) for a treatment plant (2) of a blast furnace (1), wherein the treatment plant (2) comprises a chute system with a chute (2a) driven in rotation about a vertical axis for the annular application of further raw material (9) in the blast furnace (1 ), wherein the chute system further comprises a raw material flow flap (7, 7 ') with adjustable flap position, and at least one unit (11) for determining a locally present filling level (h) of the raw material (9) in the blast furnace (1) is present, characterized in that the control system (100) is arranged, an angular velocity (ω) of the rotating chute (2a) in dependence on the determined locally present filling level (h) of the raw material (9) in the blast furnace ( 1) to change. Control system according to claim 5,
characterized in that it is further adapted to change an inclination angle (γ) of the chute (2a) in dependence on the determined locally present filling level (h) of the raw material (9) in the blast furnace (1). A furnishing installation (2) for a blast furnace (1), comprising a chute system with a chute (2a) driven in rotation about a vertical axis for the annular application of further raw material (9) to raw material (9) already present in the blast furnace (1) Chute system further comprising a raw material flow flap (7, 7 ') with adjustable flap position, and wherein at least one unit (11) for determining the local filling level (h) of the raw material (9) in the blast furnace (1) is present, characterized in that a control system (100) according to one of claims 5 or 6 is furthermore provided. Blast furnace (1) with a metering system (2) according to claim 7.

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