JP2008297616A - Method for manufacturing sintered ore - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing sintered ore by which, when controlling pallet speed in a sintering machine, it is made possible to control the thickness of a bed of raw materials for sintering on a pallet, so that the productivity can be increased while maintaining the quality of the resulting sintered ore constant. <P>SOLUTION: The method for manufacturing sintered ore is characterized in that: a sintering machine, in which raw materials for sintering are fed onto a pallet 20 by a roll feeder 19 to form a bed of raw materials for sintering and this bed of raw materials for sintering is fired to manufacture sintered ore, is used; a relationship between the speed of the pallet 20 and the number of revolutions of the roll feeder 19, by which the thickness of the bed of raw materials for sintering can be kept constant, is previously obtained; and, while controlling, when changing the speed of the pallet 20, the number of revolutions of the roll feeder 19 on the basis of the above relationship, firing of the bed of raw materials for sintering is carried out. It is preferable to control the pallet speed so that the firing completing point position of the bed of raw materials for sintering is within a prescribed range in the length direction of the sintering machine. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a method for producing sintered ore using a Dwytroid type sintering machine, which is a production apparatus for sintered ore used as a main raw material for blast furnaces and the like, and particularly for supplying raw materials onto a pallet of a sintering machine. The present invention relates to a method for controlling the number of rotations of a roll feeder.

  Sinter ore, which is the main raw material of a blast furnace, is generally manufactured as follows. First, a sintering raw material blended with fine iron ore, carbonaceous material, CaO-containing auxiliary raw materials, etc. is filled to a predetermined thickness on a pallet of a Dwytroid type sintering machine, and the surface layer of this filled sintering raw material layer After the part of the carbon material is ignited, the carbon material in the sintered raw material layer is burned while sucking air downward, and the sintered raw material is sintered by the combustion heat to obtain a sintered cake. And a sintered ore is obtained by grind | pulverizing and sizing this sintered cake.

In order to increase the productivity of the sintered ore, the firing completion point (BTP) of the sintered raw material on the pallet may be controlled so as to approach the exhausted portion at the end in the machine direction of the sintering machine. For example, Patent Literature 1 discloses a pallet speed control method aimed at keeping a firing completion point at a certain position.
JP 2005-187841 A

  However, in the conventional method of controlling the pallet speed for the purpose of keeping the firing completion point constant, the firing completion point becomes constant, but the layer of the sintering raw material layer on the pallet corresponds to the change of the pallet speed. There was a problem that the variation in thickness became large and uneven firing occurred, and as a result, the quality of the sintered ore could not be kept constant. This is because only the pallet speed is changed while the rotation speed of the roll feeder for supplying the sintering raw material onto the pallet is kept constant.

  For the above, it is considered that the layer thickness of the sintering raw material layer supplied on the pallet is measured, and the rotation speed of the roll feeder is controlled so that the layer thickness becomes constant. Because of the structure of the sintering machine, the position where the layer thickness can be measured is limited, and the distance between the measurement position and the roll feeder is long. In such a control that changes the responsiveness, the responsiveness is poor and it has not been put into practical use.

  Accordingly, an object of the present invention is to solve such problems of the prior art and to control the layer thickness of the sintering raw material layer on the pallet when controlling the pallet speed of the sintering machine. An object of the present invention is to provide a method for producing sintered ore that can maintain the quality of the ore constant and increase the productivity.

In the present invention, the pallet speed of the sintering machine has been changed by obtaining in advance the relationship between the pallet speed and the rotation speed of the roll feeder, with the layer thickness of the sintering raw material layer on the pallet of the sintering machine being constant. In some cases, the sintered ore is manufactured by controlling the rotation speed of the roll feeder based on the above relationship, and has the following characteristics.
(1) A sintered raw material layer is formed by supplying a sintered raw material on a pallet by a roll feeder to form a sintered raw material layer, and firing the sintered raw material layer to produce a sintered ore. The relationship between the speed of the pallet and the rotation speed of the roll feeder is determined in advance, and the rotation speed of the roll feeder is controlled based on the relationship when changing the speed of the pallet, A method for producing a sintered ore, wherein the sintering raw material layer is fired.
(2) The method for producing a sintered ore according to (1), wherein the pallet speed is controlled so that the firing completion point position of the sintering raw material layer falls within a predetermined range in the length direction of the sintering machine. .

  According to the present invention, the layer thickness of the sintering raw material layer on the pallet of the sintering machine can be kept constant with good response. For this reason, the quality of the sintered ore manufactured is maintained constant, the yield is improved, and the productivity of the sintered ore can be increased.

  The concept of the control method of the roll feeder which supplies a sintering raw material on the pallet of a sintering machine used with the manufacturing method of the sintered ore of this invention using FIG. 1 is demonstrated.

  In order to keep the layer thickness of the sintering raw material layer on the pallet constant, the relationship between the pallet speed of the sintering machine and the rotation speed of the roll feeder is obtained in advance. This can be done by experimentally determining the relationship between the pallet speed and the roll feeder rotation speed so that each set layer thickness is constant for a plurality of set layer thicknesses. Alternatively, if the raw material supply amount (mass per unit time) on the pallet is obtained from the rotation speed of the roll feeder and the raw material supply amount is divided by the pallet speed (movement amount per unit time), Since the mass of the sintering raw material can be calculated, the value can be calculated by converting the value into the layer thickness.

  The relationship obtained as described above is indicated by a straight line A in FIG. The horizontal axis corresponds to the sintering machine speed, and the vertical axis corresponds to the roll feeder rotation speed. In FIG. 1, the straight line A and one line are shown. However, when the layer thickness changes to a plurality of values by operation, a plurality of relational expressions are obtained depending on the type of the layer thickness.

  In the roll feeder rotation speed control device 1 (corresponding to the portion surrounded by the dotted line in FIG. 1), the sintering machine speed information B can be set by the set value from the sintering machine speed control device 2, or at a constant cycle or change. The actual pallet speed is input as an actual measurement value from the speed detector 3.

  A change amount (ΔV) of how much the value of the input sintering machine speed information B has changed from the current value (before the speed is changed or the value input last time) is calculated. The position indicated by a black circle on the straight line A is the current value. Then, the following three determinations a) to c) are made, and processing according to each case is performed.

  a) When the absolute value of the change amount is not large (in FIG. 1, ΔV is in the range of ΔVmin2 to ΔVmax1): The rotation speed of the roll feeder is not changed and is maintained as it is.

  b) When the absolute value of the change amount is too large (in the figure, ΔV is less than ΔVmin1 or greater than ΔVmax2): The rotation speed of the roll feeder is not changed and is maintained, but the change amount is too large. As an alarm. If the amount of change in the number of rotations of the roll feeder is large, control is impossible, and this is dealt with by issuing an alarm.

  c) Except for a) and b) above, the rotation speed of the roll feeder is determined corresponding to the straight line A in FIG.

  Eventually, the amount of change (speed range) for changing the rotation speed of the roll feeder becomes the range indicated by the double-headed arrow in FIG. Then, the rotation speed C determined in c) is set in the roll feeder control device 4. In FIG. 1, ΔVmin1, ΔVmin2, ΔVmax1, and ΔVmax2 are values based on the current value, ΔVmin1 and ΔVmin2 are negative, and ΔVmax1 and ΔVmax2 are positive.

  FIG. 2 is a system configuration diagram for realizing the above-described concept according to an embodiment of the present invention.

  The roll feeder rotational speed control device 1 includes a pallet speed set value input unit 11, a roll feeder rotational speed calculation unit 12, a roll feeder rotational speed setting unit 13, a correlation table 14, and a gain table 15.

  A pallet speed set value B is input to the pallet speed set value input unit 11 from the pallet control device 10 that controls the pallet speed in order to keep the firing completion point position constant. The input speed may be a measured value instead of the set value.

  In the roll feeder rotation speed calculation unit 12, the pallet speed B input by the pallet speed setting value input unit 11 and information necessary for calculating the roll feeder rotation speed for making the layer thickness constant are stored in the correlation table 14 and Input from the gain table 15 and the brand (type) of the raw material from the operation management computer 16, the rotation speed of the roll feeder corresponding to the input pallet speed is calculated.

  The roll feeder rotation number setting unit 13 sets the roll feeder rotation number calculated by the roll feeder rotation number calculation unit 12 in the roll feeder control unit 17.

  In FIG. 2, 18 is a surge hopper, 19 is a roll feeder, 20 is a sintering pallet, 21 is a sintering raw material layer, 22 is an ignition furnace, 23 is a firing completion point estimation unit, and 24 is an exhausting unit. The sintering raw material in the surge hopper 18 is supplied and filled on the sintering pallet 20 using the roll feeder 19 and sintered. By controlling the rotation speed of the roll feeder when changing the pallet speed so that the firing completion point of the sintering raw material on the pallet is within a predetermined range near the discharge section 24 at the end of the machine length direction of the sintering machine The sintered raw material layer is fired while the layer thickness of the sintered raw material layer is kept constant to produce a sintered ore.

  FIG. 3 is a diagram illustrating an example of a processing flow of the roll feeder rotation speed control device.

  In the flowchart of FIG. 3, first, following the start (31), the pallet speed measurement value V1 is input (32).

  Next, a speed change amount ΔV (ΔV = V1−V0), which is a change amount of the pallet speed at the present time (before change) and after the change, is calculated (33). V0 is the previous speed measurement value.

  The changed speed is stored as V0 for the next calculation (34).

  It is determined which range of the calculated ΔV is as follows.

  First, when the magnitude of ΔV is in the range of ΔVmin2 to ΔVmax1 (Yes in 35), the amount of change in the pallet speed is small, and there is no change in the thickness of the sintered raw material layer so as to affect the quality. The rotation speed is not controlled, and the roll feeder rotation speed is maintained as it is (36).

  Next, when the magnitude of ΔV is out of the range of ΔVmin2 to ΔVmax1 (No in 35) and is in the range of ΔVmin1 to ΔVmin2 or ΔVmax1 to ΔVmax2 (Yes in 37), the speed change amount that affects the quality As a controllable range, the following control processing is performed.

  Data shown in Fig. 1 (relational expression between pallet speed and roll feeder rotation speed when the thickness of the sintering raw material layer is constant) is read from the correlation table and corresponds to the speed after changing the pallet speed. The roll feeder rotation speed R is calculated (38).

  Further, the temperature measurement (actual measurement) value T obtained by measuring the temperature of the sintered raw material on the pallet and the sintering raw material brand (sintered raw material type) information m on the current pallet are input (39). This is because even if the raw materials have the same mass, the layer thickness of the sintered raw material layer varies depending on the temperature and brand, so that a gain for correcting it is determined.

  Based on the temperature T and the sintering material brand m, the corresponding gain G is obtained from the gain table (40).

  The value of the gain G is multiplied by the roll feeder rotation speed R obtained above to determine the rotation speed R ′ set in the roll feeder (41), and the value is set as the roll feeder rotation speed R ′ (42). ).

  Finally, if the change amount of the pallet speed is less than ΔVmin1 or greater than ΔVmax2 (No in 37), the rotation speed of the roll feeder is not changed and the current state is maintained, but an alarm is issued because the change amount is too large. (43).

  These processes are repeated for a certain period of time in the operation of the sintering machine or when the speed of the sintering machine pallet is changed, and the number of layers of the sintering raw material layer is controlled by controlling the rotation speed of the roll feeder. Firing is performed with a constant thickness to produce sintered ore. Thereby, the quality of sintered ore is made uniform and the yield is improved.

Explanatory drawing of the control method of a roll feeder. 1 is a system configuration diagram for carrying out the present invention. Explanatory drawing of the processing flow of a roll feeder rotation speed control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Roll feeder rotation speed control apparatus 2 Sintering machine speed control apparatus 3 Speed detector 4 Roll feeder control apparatus 10 Pallet control apparatus 11 Pallet speed setting value input part 12 Roll feeder rotation speed calculating part 13 Roll feeder rotation speed setting part 14 Correlation Table 15 Gain table 16 Operation management computer 17 Roll feeder control unit 18 Surge hopper 19 Roll feeder 20 Sinter pallet 21 Sintering raw material layer 22 Ignition furnace 23 Firing completion point estimation unit 24 Excavation part A To make the layer thickness constant Relation between pallet speed and roll feeder rotation speed B Sintering machine speed information (pallet speed)
C Roll feeder rotation speed

Claims (2)

  The sintering raw material layer is formed by supplying a sintering raw material on a pallet by a roll feeder, and firing the sintering raw material layer to produce a sintered ore. Is determined in advance, the relationship between the speed of the pallet and the rotation speed of the roll feeder is obtained in advance, and when changing the speed of the pallet, the rotation speed of the roll feeder is controlled based on the relationship, the sintering A method for producing a sintered ore, comprising firing a raw material layer.   2. The method for producing a sintered ore according to claim 1, wherein the pallet speed is controlled so that a firing completion point position of the sintering raw material layer falls within a predetermined range in a length direction of the sintering machine.

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