JP5023491B2 - Bellless blast furnace top charging equipment - Google Patents

Description

  The present invention relates to a furnace top charging apparatus for a bell-less blast furnace, and more particularly to a furnace top charging apparatus having a turning chute suitable for central coke charging.

  Generally, when raw materials are charged into a blast furnace, ore and coke are alternately charged in order to appropriately control the gas flow distribution in the furnace. By alternating charging of ore and coke, a stacked state of coke and ore is formed in the blast furnace, but only the coke is formed substantially in the center of the furnace, and a coke column is formed in the center of the furnace. Central coke charging methods are known. By setting it as such a charging state, an appropriate center flow is ensured, blast furnace operation is stabilized, and a coke ratio is also reduced.

In a blast furnace having a bellless furnace top charging device (hereinafter referred to as a bellless blast furnace), a raw material is charged into the blast furnace by changing the inclination angle of the swivel chute while rotating the swivel chute. To perform the above-mentioned central coke charging method in a bell-less blast furnace, a chute dedicated to the central charging is separately installed, the coke is charged in the center of the blast furnace, and the other charged raw materials are charged using a swirl chute. There are known a method of entering the center and a method of performing the center charging with the turning chute vertical. When center charging is performed with the turning chute vertical, coke discharged from the top hopper 1 is dropped through the vertical chute 2 at the center as shown in FIG. Although it is guided to the furnace center (furnace core), it is difficult to make the swivel chute completely vertical because of the structure of the equipment. In the case of charging, there is a problem that the charged coke forms a drift in the swivel chute, the dropping position in the furnace becomes unstable, and the position accuracy of the central charging is deteriorated. In order to solve such a problem, a coke oven core charging method to a blast furnace in which a flat drift plate is attached to a swivel chute and coke is dropped along the bottom surface of the swivel chute is known (for example, a patent Reference 1).
JP-A-7-126717

  However, when the above-mentioned central coke charging method is performed in a bell-less blast furnace, there are the following problems.

  In order to use a chute dedicated to central charging, it is necessary to newly install a special chute, which requires equipment equivalent to a set of raw material charging equipment for a blast furnace, although the scale is smaller than that of a normal charging equipment. The cost is high. In addition, there may be insufficient space to install a new chute in an existing blast furnace. Furthermore, in order to prevent wear of the chute dedicated to the central charging during the charging of the raw material by the turning chute, the special chute needs to have a moving mechanism. Therefore, it is often difficult to implement both in terms of cost and structure, and when using conventional equipment, a method using a turning chute is desirable.

  On the other hand, when center coke charging is performed using a swirl chute, it is said that a flat drift plate can be attached to the swirl chute so that the coke can be uniformly charged in the center of the furnace in a symmetrical manner. In addition, since the drift plate 10 is directly hit by the majority of the charges falling from the vertical chute 3, the degree of wear is remarkably high, the replacement frequency is high, and the drift plate 10 is clogged with raw material on the swivel chute. There is concern about the occurrence. Furthermore, since the charged material falls into the furnace while spreading in the width direction of the turning chute, the effect of improving the accuracy of the dropped position of the charged material is insufficient.

  Therefore, the object of the present invention is to solve such problems of the prior art and improve the accuracy of the dropped position of the charged material when charging the blast furnace with a raw material using a furnace top charging device having a turning chute. Accordingly, an object of the present invention is to provide a bell-less blast furnace top charging apparatus capable of accurately charging coke into the center of the blast furnace.

The features of the present invention for solving such problems are as follows.
(1) A bell-less type blast furnace top charging device having a turning chute used for charging a central coke of a blast furnace, wherein the turning chute is bowl-shaped and is 1 / of the length of the turning chute from the tip of the turning chute. A part of the six or more regions has a structure in which the saddle-shaped open portion is closed by a current reducing plate, the cross-sectional shape of the current reducing plate is an arc shape, and is lower than the bottom surface of the swivel chute A bellless blast furnace top charging device, characterized in that it is installed so as to be inclined so that the distance from the bottom surface becomes shorter.
(2) The bell top blast furnace top charging apparatus according to (1), wherein an end portion of the contracted plate protrudes from a lower end portion of the turning chute.
(3) The topless charging device for a bell-less blast furnace according to (1) or (2), wherein an upper end portion of the contracted plate protrudes from an end face of the swivel chute.

  According to the present invention, it is not necessary to install new equipment, and the life of the turning chute is relatively long. Therefore, blast furnace operation using the central coke charging method can be performed at low cost. In addition, since the raw material can be charged accurately in the central portion of the blast furnace, stable operation using the central coke charging method can be performed with a smaller amount of coke, and the coke ratio can be reduced.

In addition, since the drop position accuracy when charging the raw material other than the center of the furnace is improved, the distribution accuracy of the furnace interior is improved, and the gas flow in the furnace is stabilized. Thereby, the air permeability and gas utilization rate in the blast furnace are improved, the reducing material ratio of the blast furnace is reduced, and the CO ₂ emission amount can also be reduced.

  The furnace top charging device of the bell-less type blast furnace of the present invention is a furnace top charging device having a swirl chute, the swirl chute is bowl-shaped, and a part of the lower part of the bowl-shaped open part is a current-reducing plate It has a closed structure, and the cross-sectional shape of the flow contracting plate is an arc shape, and is installed to be inclined in a direction in which the distance from the bottom surface becomes shorter toward the bottom with respect to the bottom surface of the turning chute. To do. The current reducing plate is installed as a circular arc in a direction that protrudes upward with respect to the bottom of the swivel chute. The cross-sectional shape of the turning chute is usually a circular arc or a U-shape, but a square shape or the like can also be used.

  The bell top blast furnace top charging apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of a longitudinal section of a furnace top portion of a blast furnace, and the raw material discharged from one or more furnace top hoppers 1 for stocking the raw material passes through a vertical chute 2 in the center and is placed in a lower swivel chute 3. And is inserted into the furnace of the blast furnace 4 from the lower end of the turning chute 3. The swivel chute 3 has a contracted flow plate 5 in the vicinity of its lower end 3a. FIG. 2 shows an enlarged view of the vicinity of the lower end 3 a of the turning chute 3. 2A is a perspective view, and FIG. 2B is a cross-sectional view as seen from the side.

  In FIG. 2, the contracted flow plate 5 is attached so as to narrow the flow with respect to the flow of the raw material 6 in the turning chute 3. The reduced-flow plate 5 has an arc shape (arch shape) in cross section, is less likely to be clogged with raw material, prevents the raw material from spreading in a wide range in the radial direction in the swivel chute, and the raw material that collides with the reduced-current plate 5 is Since it bounces back toward the center of the arch, the flow of the raw material is sufficiently contracted, and the accuracy of the falling position of the raw material can be improved. Since the current reducing plate 5 is installed not only on the entire swivel chute but only on the lower part near the tip, wear due to the raw material falling from the vertical chute hardly occurs. In FIG.2 (b), the part shown by the arrow is the raw material part by which the flow was shrunk | reduced.

  By projecting the front end portion of the current reducing plate 5 from the lower end portion of the swivel chute, the opening cross-sectional area through which the raw material flows out can be increased and the clogging of the raw material can be sufficiently prevented. In addition, since the contracted flow plate 5 is installed obliquely with respect to the turning chute, the upper end portion of the reduced flow plate 5 (the right end portion in FIG. 2 (b) and the end portion opposite to the lower turning portion of the turning chute). ) May protrude beyond the end face of the turning chute. By sufficiently projecting the upper end of the contracted plate 5, the raw material is prevented from overflowing without passing between the swivel chute and the contracted plate, and it is possible to contract even when the flow rate of the raw material is large. Can be possible.

  It is preferable that the area for attaching the current reducing plate be an area that is 1/6 or more of the length of the turning chute from the tip of the turning chute. This is because it was confirmed from the results of the model experiment that the region in which the deviation of the raw material toward the side wall portion of the turning chute is particularly large is within the above range. The wider the area where the current reducing plate is attached, the more effective, but the size of the current reducing plate needs to be within the load resistance range of the swivel reducer for the swivel chute. FIG. 3 is an embodiment of the present invention, and is a schematic view of a longitudinal section in the length direction (raw material charging direction) of the turning chute. In this case, the turning chute length L from the tip of the turning chute is shown. The flow-reducing plate 5 is attached to the 1/4 region.

  As for the shape of the opening part of the turning chute chute, the length in the vertical direction is preferably 6 times or more the charged raw material particle diameter, and the length in the width direction is preferably substantially equal to the diameter of the turning chute. A preferred shape of the opening will be described with reference to FIGS. FIG. 4 shows the shape of the opening at the cross section AA ′ that intersects the contracted plate at a right angle in FIG. 3 and passes through the lower end of the swivel chute, and the opening vertical dimension X is set to prevent clogging of the raw material. It is preferable to secure 6 times the charged raw material particle size. Further, it is preferable that the lateral dimension Y of the opening is set as equal as possible to the diameter of the turning chute in order to prevent uneven wear of the turning chute wear prevention liner. As described above, the shape of the opening of the turning chute tip is preferably set as an arc as shown in FIG. 4 where the opening vertical dimension X and the opening horizontal dimension Y satisfy the above-described conditions.

  It is preferable to set the installation angle (θ shown in FIG. 3) of the current reducing plate with respect to the turning chute to an angle determined from the installation region of the current reducing plate and the shape of the opening of the turning chute tip.

  When the upper end portion (the end portion opposite to the lower end portion of the turning chute) of the current reducing plate is protruded from the end surface of the turning chute, the length of the protruding portion may be about 10% or less of the turning chute radius. preferable. In FIG. 3, D is the radius of the turning chute, and the protruding portion d is 10% of the length of D.

  The effect when the raw material is charged using the topless charging apparatus of the bell-less type blast furnace of the present invention shown in FIGS. 1 and 2 will be described with reference to FIG. FIG. 5 is a schematic view of a cross section of the top portion of the blast furnace, in which the turning chute 3 is tilted and rotated at the position 3A or 3B and the raw material is charged into the furnace.

  First, in the case where the raw material is charged in the furnace peripheral portion, the turning chute 3 is set at an angle as indicated by 3A in FIG. Conventionally, the tip (lower end) of the turning chute has a semi-cylindrical shape with the upper side open. Therefore, when turning, the raw material 6 drifts in the chute so as to deviate in the direction opposite to the rotation direction, and spreads as shown by the dotted line 6A. However, the flow is reduced as indicated by the solid line 6B due to the presence of the reduced flow plate 5, and the accuracy with respect to the drop setting position is improved.

  Next, in the case where the raw material is charged into the center of the furnace, the turning chute 3 is set to an angle as close to vertical as possible as indicated by 3B in FIG. Conventionally, when the raw material falls from the vertical chute 2 to the swivel chute 3, some of the raw material falls directly from the vertical chute into the furnace, and there is a portion where the contraction effect due to the swirl chute does not occur. Even in the raw material of the small part, the contraction effect is generated by the contraction plate 5, and the drop position accuracy is improved. Since this effect has the same contraction effect as that in the furnace peripheral part, the drop position accuracy in the furnace center part can be improved very effectively.

  The present invention is particularly effective when used in a parallel hopper, in particular, a charging device having a hopper installed in parallel at three or more furnace tops. This is because in the parallel hopper, since the hopper is not installed on the core shaft, the charging position when the raw material is charged is likely to be biased.

  Another embodiment of the present invention will be described with reference to FIG. A front view and a side view of the lower end 3a of the turning chute 3 are shown in FIGS. 6 (a) and 6 (b). As shown in FIG. 6A, the contracted plate 5 is installed in a direction having a convex shape opposite to the turning chute, and as shown in FIG. It is installed with an angle that has a downward slope toward. The front end portion of the flow contracting plate 5 is positioned substantially the same as the front end portion 3 a of the turning chute 3. When the coke is charged into the center part of the blast furnace using the swirl chute shown in FIG. 6 and when the coke is charged into the center part of the blast furnace using a swirl chute that is not provided with a conventional flow reduction plate Fig. 7 shows the result of measuring the mass distribution in the radial direction of the charged coke in the furnace. In FIG. 7, the position in the furnace radial direction, which is the horizontal axis, is indicated by a dimensionless radius with the blast furnace radius being R. The case where the turning chute shown in FIG. 6 is used is a black circle (●), and the case where a conventional turning chute without a current reducing plate is used is a white circle (◯). In the conventional apparatus, even if an attempt is made to charge coke into the core portion (around r / R = 0), a peak is formed at a position slightly away from the core portion (around r / R = 0.15). It can be seen that a mass distribution having a peak in the core portion is formed by using the furnace top charging apparatus of the invention. In this way, by forming a coke deposit layer in the center portion of the furnace using the apparatus of the present invention, it is possible to prevent ore from flowing into the center portion of the furnace and to secure a central flow in the furnace. As a result, an effect of improving the furnace condition such as reduction of the coke ratio can be obtained.

The schematic of the longitudinal cross-section of the furnace top part of a blast furnace. BRIEF DESCRIPTION OF THE DRAWINGS It is one Embodiment of this invention, (a) The perspective view of the lower end part of a turning chute, (b) Sectional drawing which looked at the lower end part of the turning chute from the side. The schematic diagram of the longitudinal section in the length direction of the turning chute of the present invention. The figure which shows the shape of the opening part in the cross section A-A 'in FIG. The schematic of the cross section of the furnace top part of a blast furnace. It is other embodiment of this invention, (a) The front view of the lower end part of a turning chute, (b) The front view side view of the lower end part of a turning chute. The graph which shows the comparison of the mass distribution of the radial direction in the furnace of a charge at the time of using this invention apparatus ((circle)) and a conventional apparatus ((circle)). The schematic of the longitudinal cross-section of the furnace top part of a blast furnace which shows an example of the conventional furnace top charging apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Furnace top hopper 2 Vertical chute 3 Swing chute 3a Swing chute lower end part 3A, 3B Swing chute position 4 Blast furnace 5 Current reducing plate 6 Raw material 6A, 6B Raw material position 10 Current drift plate D Radius of swirling chute d Projection part length L Swing chute Length X Vertical dimension of the opening Y Horizontal dimension of the opening θ Installation angle of the contracted flow plate

Claims (3)

A bell-less blast furnace top charging device having a swivel chute used for charging a central coke of a blast furnace, wherein the swivel chute has a bowl shape and is at least 1/6 of the swivel chute length from the tip of the swivel chute A part of the region has a structure in which the bowl-shaped open portion is closed by a current reducing plate, the cross-sectional shape of the current reducing plate is an arc shape, and A bell-less blast furnace top charging device, characterized in that it is installed with an inclination in a direction that shortens the distance of the blast furnace.   The endless charging plate of the bell-less type blast furnace according to claim 1, wherein an end portion of the reduced flow plate protrudes from a lower end portion of the turning chute. 3. The topless charging device for a bell-less blast furnace according to claim 1 or 2, wherein an upper end portion of the reduced flow plate protrudes from an end face of the swivel chute.

Images