STAVE AND BLAST FURNACE
5 Field of the Invention
[0001]
Priority is claimed on Japanese Patent Application No. 2010-036841, filed on
February 23, 2010, the content of which is incorporated herein by reference.
10 Related Art
[0002]
In existing blast furnaces, a structure where a stave is installed inside a shell and
refractory brick is installed inside the stave is often used. The inner surface of the blast
furnace is exposed to a charging material that descends inside the furnace while being
15 subjected to high heat within the furnace, and is subjected to mechanical wear. The
surface of the stave wears out after a predetermined period of time passes and the
refractory brick wears out. In order to cope with such wear, a structure in which
recesses are formed on the surface of the stave inside the furnace, and refractories are fit
into the recesses, or the like, has been developed (refer to Patent Document 1).
20
Reference Document
Patent Document
[0003]
[Patent Document 1] Japanese Unexamined Patent Application, First
25 Publication No. 2001-49316
2
Disclosure of the Invention
Problems to be Solved by the Invention
[0004]
5 Among blast furnaces, in a shaft section (from a middle part to an upper part in a
shaft), a charging material is stratified granular coke and iron ore (sintered ore, lump ore,
or the like), and a stave of this part is subjected to mechanical wear caused by particles of
the charging material. The durability of the aforementioned fitted refractory is not
sufficient with regard to such mechanical wear.
10 [0005]
An object of the invention is to provide a stave and a blast furnace in which
sufficient durability is obtained even with regard to mechanical wear caused by particles
of a charging material.
15 Methods for Solving the Problems
[0006]
The invention is based on the knowledge obtained as a result of a thorough
investigation carried out by the present inventors, that is, the knowledge that mechanical
wear caused by particles of a charging material depends on the shape, hardness, and
20 descending speed of the particles of the charging material, and that wear can be
significantly relieved by suppressing (forming stagnation layers) the speed of the
charging material on the surface of the stave . The invention suppresses the speed of the
charging material on the surface of the stave on the basis of the aforementioned
knowledge. As a configuration for forming the stagnation layers, projections are
25 formed on the surface of the stave inside the blast furnace, and the stagnation layers of
3
the charging material that covers the surface of the stave are made to be easily generated.
The specific configuration is as follows.
[0007]
The invention has adopted the following means in order to solve the above
5 problems and achieve the relevant object.
(1) A stave related to an aspect of the invention is a stave provided on an inner
periphery of a shaft section of a blast furnace. The stave includes a stave body having a
reference plane facing an internal space of the blast furnace; and a plurality of
protrusions that protrudes from the reference plane toward an inner side of the blast
10 furnace.
According to the stave described in the above (1), the furnace inner surface of
the blast furnace is constituted by the reference plane of the stave body, and the charging
material that descends inside the furnace is decelerated by the protrusions that protrudes
from the reference plane toward the inner side of the furnace, whereby stagnation layers
15 are formed along the reference plane. The relative velocity of the stagnation layers with
respect to the reference plane of the stave body is lower, mechanical wear of the 1
reference plane of the stave body caused by the particles of the charging material is
relieved, and sufficient durability against the granular charging material that descends in
the shaft section of the blast furnace is also obtained.
20 [0008]
(2) In the stave described in the above (1), preferably, a protruding dimension of
the protrusions is 50 to 150 mm, and a spacing between adjacent protrusions is 200 to
700 mm.
According to the stave described in the above (2), the protrusions (protruding
25 dimension: 50 to 150mm, and spacing: 200 to 700 mm) are formed. Thus, the charging
4
material is decelerated, and particularly the movement of some of the charging material
is stopped by the protrusions, and stagnation layers are formed.
Since a planar surface is covered with the stagnation layers as a result of the
formation of such stagnation layers, the deceleration effect on the charging material is
5 strengthened.
Additionally, in such a stave, the stagnation layers are easily formed along the
reference plane of the stave body on a charging material that is currently common, that is,
an ore-based charging material with a particle size of about 8 to 25 mm and the
coke-based charging material with a particle size of about 20 to 55 mm are alternately
10 charged. This can suppress the speed of the charging material particles on the surfaces
of the tips of the protrusions, and exhibit an overall wear-relieving effect in the stave. If
the spacing is smaller than 200 mm, a dent formed by adjacent protrusions along the
reference plane of the stave body becomes less effective, and the charging material is not
easily caught. On the other hand, if the spacing is larger than 700 mm, the spacing
15 between the stagnation layers is increased, and a coating effect is not sufficiently
exhibited.
[0009]
(3) In the stave described in the above (1), desirably, the protrusions are
continuously or intermittently provided along a circumferential direction of the blast
20 furnace.
According to the stave described in the above (3), the protrusions that are
continuous on the whole circumference in the furnace circumferential direction enable
circumferential balance within the furnace to be appropriately and easily maintained, and
enable operation performance to be favorably maintained.
25 Additionally, the protrusions may be intermittently arranged in the furnace
5.
circumferential direction. In this case, although various geometric patterns, such as a
grid shape and a zigzag shape, can be adopted, it is always preferable to arrange the
protrusions point-symmetrically in consideration of circumferential balance.
[0010]
5 (4) In the stave described in the above (1), desirably, surfaces of the protrusions
are formed of a material with high-hardness.
According to the stave described in the above (4), wear prevention of the
protrusions themselves can be achieved. In the stave of one aspect of the invention,
relief of wear in the reference plane of the stave body is achieved by forming (self-lining)
10 the stagnation layers derived by the protrusions. However, the protrusions themselves
are exposed to the inner side of the furnace from the stagnation layers, and accordingly
receive the wear caused by particles of the charging material that are not decelerated. In
this case, by forming the surfaces of the protrusions of a material with high hardness,
wear of the protrusions can be suppressed and the stagnation layers derived by the
15 protrusions are formed. This enables wear relief of the reference plane of the stave
body due to the stagnation layers to be stably maintained for a long period of time.!.
[0011]
(5) In the stave described in the above (4), preferably, the stave body is formed
with recesses, the protrusions are a block embedded in the recesses and protrudes from
20 the reference plane, and the block is formed of a material with high hardness.
According to the stave described in the above (5), a configuration in which the
protrusions are provided in the recesses formed in•thestave body is provided, that is, the
stave body and the protrusions are separate. Therefore, the protrusions can be simply
formed of a material with high hardness different from the material of the stave body.
25 (6) Alternatively, in the stave described in the above (4), it is preferable that the
6
protrusions be formed integrally with the stave body.
According to the stave described in the above (6), the surfaces of the protrusions
according to the aforementioned high-hardness material can be easily formed, and the
protrusions are formed integrally with the stave body. Therefore, manufacture is easy.
5 Particularly, in a case where cooling conduits also passes through the protrusions, it is
extremely beneficial to working that the protrusions and the stave body are integral.
[0012]
(7) In the stave described in the above (1), desirably, the stave body is a copper
or a copper alloy.
10 According to the stave described in above (7), the cooling efficiency of the stave
used for the shaft section can be enhanced. The cooling capability of a stave made from
copper or a copper alloy is high, whereas it is susceptible to the wear caused by the
particles of the charging material. However, the wear of the stave body can be
mitigated by the stagnation layers based on one aspect of the invention. Moreover, high
15 cooling capability can be maintained for a long period of time.
[0013]
(8) In the stave described in the above (1), desirably, conduits that cool the
protrusions are provided inside the protrusions.
According to the stave described in the above (8), in addition to usual cooling
20 conduits that are provided in the stave body, the protrusions can be directly cooled by the
conduits that cool the protrusions. Therefore, the hardness of the surfaces of the
protrusions can be kept high and the wear-preventing effects can be maintained for a long
period of time.
[0014]
25 (9) In the stave described in the above (1), preferably, an angle, which is formed
7
between a lower lateral face of the protrusion on two lateral faces of the protrusion on
both end sides of the reference plane, and the reference plane, is less than 90 degrees.
According to the stave described in the above (9), since the angle formed
between the lower lateral face of the protrusion and the reference plane is less than 90
5 degrees, the charging material is easily supported by the inclined protrusions. Since this
can further suppress the charging material from descending downward, sufficient
durability is obtained even against mechanical wear.
[0015]
(10) A blast furnace related to one aspect of the invention includes the stave
10 described in any one of the above (1) to (9).
Here, the stave based on one aspect of the invention is desirably installed in a
portion where the charging material descended as being granular, at the shaft section of
the blast furnace and its surroundings.
In such a stave, even if there is a charging material that descends as being
15 granular, stagnation layers are formed by the protrusions of the stave, and wear of the
reference plane of the stave body is reduced. In the shaft section of the blast furnace,
progress of the wear caused by the granular charging material causes difficulty in
operation in view of a blast furnace. However, since the wear-resistant stave is installed
at this portion, the operation can be stably performed, and the lifespan of the blast
20 furnace can be extended.
Brief Description of the Drawings
[0016]
FIG 1 is a schematic view showing a blast furnace of a first embodiment of the
25 invention.
8
FIG. 2 is a cross -sectional view showing a stave of the first embodiment.
FIG. 3 is a front view showing the stave.
FIG. 4A is a perspective cross-sectional view showing the stave.
FIG. 4B is a perspective cross -sectional view showing a modification of the
5 stave.
FIG. 5 is a back view showing the stave.
FIG. 6 is atschematic view showing the effects of the first embodiment.
FIG. 7 is a schematic view showing the effects of a comparative example of the
first embodiment.
10 FIG. 8 is a schematic view showing the effects of the comparative example of
the first embodiment.
FIG. 9 is a graph showing the test results of the first embodiment.
FIG. 10 is a graph showing the test results of the first embodiment.
FIG. I1 is a cross-sectional view showing a stave of a second embodiment of the
15 invention.
FIG. 12 is a front view showing the stave.
FIG. 13 is a back view showing the stave.
FIG. 14 is a cross-sectional view showing a stave of a third embodiment of the
invention.
20 FIG. 15 is a front view showing the stave.
FIG 16 is a back view showing the stave.
FIG 17 is a cross-sectional view showing a stave of a fourth embodiment of the
invention.
FIG. 18 is a front view showing the stave.
25 FIG. 19 is a back view showing the stave.
9
Detailed Description of the invention
[0017]
Hereinafter, an embodiment of the invention will be described with reference to
5 the drawings,
(First Embodiment)
In FIG. 1, a blast furnace 1 has a tubular furnace body 2 constructed on the
foundation ground.
The furnace body 2 is tubular and is sequentially classified into a furnace throat
10 section S 1, a shaft section S2, a furnace belly section S3, a bosh section S4, a tuyere
section S5, and a furnace bottom section S6 from an upper gas trap mantel 3. Generally,
the internal diameter of the shaft section S2 is increased downward, the internal diameter
of the furnace belly section S3 is a maximum diameter, and the internal diameter of the
bosh section S4 is reduced downward.
15 [0018]
In the furnace body 2, usually, a charging device is mounted on the gas trap
mantel 3, and a granular charging material 4 is charged into the blast furnace I from the
charging device. As the charging material 4, an ore-based charging material with a
particle size of approximately 8 to 25 mm and a coke -based charging material with a
20 particle size of about 20 to 55 mm are alternately charged. As a result, a lumpy zone 4A
in which iron ore and coke are alternately stratified is formed in the furnace throat section
S 1 and the shaft section S2 within the furnace.
In the furnace body 2, a tuyere 5 is installed in an upper part of the furnace
bottom section S6, and a hot blast 5A is blown into the furnace body from here. The
25 temperature is sequentially raised by the hot blast 5A as the coke in the lumpy zone 4A
10
descends within the furnace, and a raceway SB (the space with a high void ratio when
high-speed gas is blown from the tuyere 5 and the coke before the tuyere 5 is fluidized)
caused by high-temperature gas is formed in the vicinity of the tuyere 5. According to
the high heat of the raceway 513, the iron ore in the lumpy zone 4A melts.
5 [0019]
The combustion of the coke and the melting of the iron ore proceeds
sequentially in a lower part of the lumpy zone 4A, and a roughly conical cohesive zone
4B is formed from the bosh section S4 toward a lower part of the shaft section S2 within
the blast furnace 1.
10 The iron 6A that has melted in the cohesive zone 4B passes through a dropping
zone 4C, drops toward the furnace bottom section S6, and accumulates in the furnace
bottom section S6 as hot metal 6B. The coke or the like descends through the dropping
zone 4C, piles up on the furnace bottom section S6, and forms a conical furnace core 4D
on the hot metal 6B.
15 In the furnace body 2, a tap hole 6 is installed in the furnace bottom section S6,
and the hot metal 6B that has accumulated in the furnace bottom section S6 is taken out
to the outside of the blast furnace 1 via the tap hole 6.
[0020]
The furnace body 2 has a shell 2A at the outermost periphery thereof, and a
20 cooling stave or refractory brick 2D is affixed inside the shell 2A.
A shaft stave 2B is stretched in a region S7 that faces the lumpy zone 4A from
an upper part to a middle part in the shaft section S2. In the region S7, since the
granular charging material 4 included in the lumpy zone 4A descends sequentially while
coming into contact with the surface of the stave 2B, mechanical wear may be caused on
25 the surface of the stave 2B.
11
A stave 2C for a bosh section and a furnace belly section is affixed to the inner
periphery of a region S8 including the furnace belly S3 and the bosh section S4 from the
lower part of the shaft section S2. In the region S8, since a high-temperature charging
material 4 (cohesive zone root part) included in the cohesive zone 4B descends
5 sequentially while coming into contact with the surface of the stave 2C, wear caused by
high temperature may arise on the surface of the stave 2C.
The heat-resistant brick 2D is stretched across the surfaces of the staves 2B and
2C inside the blast furnace 1 as necessary. Additionally, a heat-resistant brick 2E
thickly piles up on the furnace bottom section where high-temperature melting iron is
10 stored.
[0021]
In the present embodiment, a shaft stave 10 shown in FIG. 2 is adopted as the
shaft stave 2B shown in FIG. 1.
In the present embodiment of FIGS. 2, 3, 4A, 4B, and 5, the shaft stave 10
15 includes a stave body 11 having a reference plane R that faces the internal space of the
blast furnace 1, and a plurality of protrusions 12 that protrudes more toward the inside of
the blast furnace 1 than the reference plane R. In the present embodiment, the
protrusions 12 are formed integrally with the stave body 11. Additionally, the stave
body 11 is in the shape of a thin plate shaved off from a plate material made of copper or
20 copper alloy. The shaft stave 10 maybe made of casting or cast iron that is made of
copper or copper alloy which is cast in bulk.
As shown in FIGS. 2 and 3, a plurality of rows of protrusions 12 is horizontally
and continuously formed on the surface side of the stave body 11. As shown in FIG 2,
a planar surface 13 that is sunken is formed between the plurality of protrusions 12.
25 One groove 21 is formed in the planar surface 13, and the refractory brick 15 is fitted into
12
the groove 21.
Additionally, a refractory castable may be used instead of the refractory brick 15.
Additionally, the number and location of grooves 21 is not limited to this.
[0022]
5 The plurality of protrusions 12, as shown in FIG. 4A, is horizontally and
continuously provided on the surface side of the stave body 11. In addition, FIG 4A is a
view in which the groove 21 is omitted.
The planar surface 13 is formed by cutting from the surface of the stave body
11, and the protrusions 12 are formed by being left behind during this cutting. Here, the
10 planar surface 13 is the reference plane R of the shaft stave 10, and the protrusions 12
protrude from the reference plane R in the shaft stave 10.
[0023]
In a case where the shaft stave 10 is affixed into the blast furnace 1, as shown in
FIG 4A, the protrusions 12 are provided continuously along the circumferential direction
15 of the blast furnace 1, and each protrusion 12 forms a perfect annular shape in the blast
furnace 1.
Additionally, the protrusions 12, as shown in FIG 4B, may be arranged
intermittently along the circumferential direction within the blast furnace 1. In this case,
- although various geometric patterns, such as a grid shape and a zigzag shape, can be
20 adopted, it is always preferable to arrange the protrusions point-symmetrically in
consideration of circumferential balance. In addition, FIG 4B is a view in which the
groove 21 is omitted.
[0024]
Moreover, the angle 0, which is formed between a lower lateral face of the
25 protrusion 12 on two lateral faces 12a and 12b of the protrusion 12 on both end sides of
13
the reference plane R, that is, a lateral face 12a and the reference plane R, is less than 90
degrees. Specifically, the lateral face 12a is horizontal with respect to the ground at an
installation location when the blast furnace 1 is installed.
In addition, as shown in FIG 2, bolt receiving portions I I A for mounting the
5 blast furnace I are formed on the rear surface side of the stave body 11.
[0025]
As shown in FIG. 5, connection ports 16A and 17A of cooling conduits are
formed on the rear surface side of the stave body 11, and cooling conduits 16 and 17 are
formed inside the stave body 11.
10 The conduits 16 are arranged along the planar surface 13, and the planar surface
13 that is the reference plane R of the shaft stave 10 can be cooled by the cooling water
supplied from the connection ports 16A.
Additionally, the conduits 17 that cool the protrusions 12 are provided inside the
protrusions 12. This configuration enables the protrusions 12 to be cooled by the
15 cooling water supplied from the connection ports 17A.
[0026]
It is preferable that the tip faces of the protrusions 12 be coated with a material
with high hardness, such as TiN, TiC, WC, and Ti-Al-N systems.
As for the protrusions 12 of the shaft stave 10, as shown in FIG 2, the amount E
20 of protrusion from the reference plane R (protruding dimension) is 50 to 150 mm (almost
1 to 3 times the maximum particle size of 55 mm of a coke-based charging material with
a large average particle size), the thickness T in the height direction is 50 to 150 mm, and
the spacing D with another adjacent protrusion 12 (equivalent to the dimension of the
planar surface 13 in the height direction) is 200 to 700 mm and preferably 250 to 350 mm
25 (300nun ±50mm).
14
[0027]
The effects of the shaft stave 10 of the present embodiment in which the spacing
D between adjacent protrusions 12, is 200 to 700 mm, more than 700mm, and less than
200 mm will be described with reference of FIGS. 6 to 8.
5 FIG. 6 schematically shows a state during the operation of the shaft stave 10 of
the present embodiment (the protruding amount of the protrusions E: 50 to 150 mm and
the spacing D: 200 to 700 mm). The enlarged shape of the shaft stave 10 of the present
embodiment is schematically shown at an upper part of FIG. 6. Additionally, a graph of
descending speeds VI and V2 at a crossing position PI and a crossing position P2 at the
10 upper part of FIG. 6 is shown at a lower part of FIG. 6.
FIG. 7 shows a case where the spacing D between the protrusions 12 is
extremely large (the spacing D between the protrusions 12 >700 mm). The enlarged
shape of the shaft stave 10 is schematically shown at an upper part of FIG. 7.
Additionally, a graph of descending speeds V3 and V4 at. a crossing position P3 and a
15 crossing position P4 at the upper part of FIG. 7 is shown at a lower part of FIG. 7.
FIG 8 shows a case where the spacing D between the protrusions 12 is small
(the spacing D between the protrusions <200 mm). The enlarged shape of the shaft
stave 10 is schematically shown at an upper part of FIG. 8. Additionally, a graph of a
descending speed V5 at a crossing position P5 at the upper part of FIG. 8 is shown at a
20 lower part of FIG. 8.
[0028]
In the respective drawings, the charging material 4 descends inside the blast
furnace I (refer to FIG. 1) during operation. The charging material 4 within the blast
furnace I descends at a substantially constant speed. The charging material 4
25 decelerates due to friction with the shaft stave 10 in the vicinity of the surface (reference
15
plane R) of the shaft stave 10. Thereby, a low-speed region is generated between the
stave 10 and a boundary B in the charging material 4 in the vicinity of the shaft stave 10.
As a result, although the descending speed of the charging material 4 is substantially
constant (average descending speed VO) inside the furnace than the boundary B, the
5 descending speed becomes slower gradually from the boundary B to the reference plane
R of the stave 10. Changes in the descending speed in this case differ greatly depending
on the shape of the reference plane R in the shaft stave 10, that is depending on, the
installation state of the protrusions 12.
[0029]
10 As shown in FIG. 6, in a case where the protrusions 12 (the protruding amount
E: 50 to 150 mm, the spacing D: 200 to 700 mm) based on the present embodiment are
formed, the charging material 4 decelerates in the part from the boundary B to the
reference plane R in the shaft stave 10, and particularly the motion of a portion of the
charging material 4 is stopped by the protrusions 12, forming stagnation layers 19 and
15 18.
The stagnation layers 19 and 18 are generated on the top face side of the j
protrusions 12 of the shaft stave 10, and grow upwards along the planar surface 13 that is
the reference plane. The motion of the stagnation layer 19 on the deep inside is nearly
stopped and the stagnation layer 18 inside the blast furnace 1 is in a state where the
20 descending speed of the stagnation layer 18 is very slow, while being gradually replaced.
Since the planar surface 13 is covered with the stagnation layers 19 and 18 as a
result of the formation of such stagnation layers 19 and 18, the deceleration effect on the
charging material 4 is strengthened.
[0030]
25 Considering the descending speed V1 at the crossing position P 1, the average
16
descending speed VOI is substantially constant inside the blast furnace 1. The boundary
B is the position with a distance B 1 from the reference plane R in the shaft stave 10, and
the descending speed V1 decreases from the boundary B to the reference plane R and
becomes a descending speed V W 1 in the reference plane R. The descending speed
5 VW 1 becomes very slow due to the formation of the stagnation layers 19 and 18, and
wear of the stave body 11 of the shaft stave 10 is suppressed.
[0031]
If the descending speed V2 at the crossing position P2 is seen, an average
descending speed V02 inside the blast furnace 1 is the same as an average descending
10 speed VOl at the crossing position P1, and the descending speed decreases from the
boundary B to the reference plane R of the shaft stave 10. At this time, the descending
speed V 1 is the same as the descending speed V2. In tip faces RI of the protrusions 12,
the descending speed becomes VL2. Here, the distance from the reference plane R to
the tip faces RI is equivalent to the protruding dimension E of the protruding portion 12.
15 The descending speed VL2 becomes the same as the descending speed VL1 at a
position equivalent to the tip faces R at the crossing position Pl I. At the crossing j.
position P1, internal friction becomes larger at a boundary portion between the charging
material 4 of the stagnation layers 19 and 18 formed by the protrusions 12 and the
descending charging material 4, and the descending speed VLl at the tip faces RI
20 becomes slower. The descending speed VL2 is influenced by the descending speed
VL1, and becomes the same descending speed as the descending speed VL1.
[0032]
As shown in FIG. 7, in a case where the spacing D between the protrusions 12 of
the shaft stave 10 is extremely large (the spacing D between the protrusions >700 mm),
25 the boundary B is a position with a distance B3 from the reference plane R of the shaft
17
stave 10, and the deceleration of the charging material 4 occurs in the part from the
boundary B to the reference plane R. However, the stagnation layers 19 and 18 formed
by the protrusions 12 as shown in FIG. 6 are not formed over the total range of a height
W of a recess but formed only in a lower end part of the height W.
5 If the descending speed V3 at the crossing position P3 is seen, an average
descending speed V03 inside the blast furnace 1 is the same as the average descending
speed VO1 at the crossing position P1, and the descending speed decreases from the
boundary B to the reference plane R of the shaft stave 10. At this time, although the
descending speed decreases similar to the descending speed V l,, since the spacing D
10 between the protrusions 12 is extremely large, the influence of the stagnation layers 19
and 18 on the planar surface 13 is small, and the descending speed of the planar surface
13 becomes the frictional force between the planar surface 13 and the charging material 4.
As a result, in a case where the spacing D between the protrusions 12 of the shaft stave
10 is extremely large, the descending speed seldom decreases.
15 [0033]
If the descending speed V4 at the crossing position P4 is seen, an average
descending speed V04 inside the blast furnace 1 is the same as an average descending
speed V03 at the crossing position P3, and the descending speed decreases from the
boundary B to the reference plane R of the shaft stave 10. At this time, although the
20 descending speed decreases similarly to the descending speed V3, the descending speed
becomes the descending speed VL4 at the tip faces RI of the protrusion 12. Here, the
distance from the reference plane R to the tip faces Rl is equivalent to the protruding
dimension E of the protruding portion 12.
The descending speed VL4 becomes faster than the descending speed VL3 at the
25 tip faces RI at a relative position , at the crossing position P3. In a section at the
18
crossing position P3 from the boundary B to the reference plane R and a section at the
crossing position P4 from the boundary B to the tip faces RI, the section at the crossing
position P4 is smaller. That is, since the distance of the crossing position P4 from the
boundary B to the tip faces RI is shorter compared with the distance of the crossing
5 position P3 from the boundary B to the reference plane R, the descending speed VL4
becomes faster than the descending speed VL3 if the same charging material 4 passes.
[0034]
In the reference plane R in the shaft stave 10, the descending speed VW3 at the
reference plane R becomes markedly higher than the descending speed VW 1, and the
10 wear of the planar surface 13 that is the reference plane of the stave body increases
significantly from the state of FIG. 6.
As such, since formation of the stagnation layers 19 and 18 is formed only in the
lower end part of the height W of the recess if the spacing D between the protrusions 12
of the stave 10 is extremely large, the wear of the planar surface 13 that is the reference
15 plane R of the stave body 11 increases significantly in the portion (tipper end part of the
height W) in which the stagnation layers 19 and 18 are not formed.
[0035]
As shown in FIG. 8, in a case where the spacing D between the protrusions 12 is
small (the spacing D between the protrusions <200 mm), the boundary B is a position
20 with a distance B5 from the reference plane R of the shaft stave 10, and the speed of the
charging material 4 decreases in the part from the boundary B to the reference plane R of
stave body. However, since flat surfaces are formed at the tip faces Rl of the
protrusions 12, it becomes the frictional force between the charging material 4 and the
flat surface, and the deceleration effect as described in FIG. 6 is no longer obtained.
25 1 [0036]
19
If the descending speed V5 at the crossing position P5 is seen, the descending
speed is an average descending speed V05 inside the blast furnace 1, and the descending
speed V5 decreases from the boundary B to the reference plane R of the stave body 11,
but becomes a descending speed VL5 at the tip faces RI of the protrusions 12. Since
5 the stagnation layer 19 is formed from the tip face Rl to the reference plane R of the
stave body, the descending speed is almost O. However, since a flat surface is formed at
the tip faces Rl, it becomes the frictional force between the charging material 4 and the
flat surface , and the descending speed VL5 becomes faster than the descending speed
VL2.
10 [0037]
As such, in the shape of FIG. 8, flat surfaces are formed at the tip faces Rl of the
protrusions 12, and the deceleration effect as described in FIG. 6 is no longer obtained.
Each descending speed VL5 with respect to the tips of the protrusions 12 is higher than
the descending speed VL2 in FIG. 6, and the wear of the tips of the protrusions 12
15 becomes larger.
[0038]
As described above, in the shaft stave 10 of the present embodiment, the
descending speed of the charging material 4 that comes into contact with the shaft stave
10 changes depending on the arrangement of the protrusions 12, that is, the spacing
20 between adjacent protrusions 12.
Here, a suitable range of the spacing D between the protrusions 12 will be
described from test results based on a 1/10 model of the shaft stave 10 of the present
embodiment.
FIG. 9 is a graph obtained by changing the spacing D between the protrusions 12
25 of the shaft stave 10 to 0 to 120 nun in the configuration of FIG 6 mentioned above, and
20
measuring the descending speed VW (that is, the speed of the charging material 4 in
contact with the surface of the planar surface 13 that is the reference plane of the stave
body) at the reference plane R of the charging material 4 in each spacing D.
Additionally, FIG. 10 shows a graph obtained by measuring the descending
5 speed VL (that is, the speed of the charging material 4 that comes into contact with the
tips of the protrusions 12) at the tip faces RI in the configuration of FIG. 6 mentioned
above. The thickness T of the protrusions 12 of the shaft stave 10 is set to 5 mm, and
measurement is made in cases where the protruding amount E is 5 mm and 10 mm. A
flat dotted line in the drawing represents the average descending speed VOl in the blast
10 furnace 1, and the descending speed is 2.4 mm/second in this test.
[0039]
It can be seen from FIG. 9 that the descending speed VW at the reference plane
R of the body of the shaft stave 10 is lower than the average descending speed VO at all
the measured setting, and particularly if the spacing D between the protrusions 12
15 becomes 100 mm or less, the descending speed VW decreases greatly. Additionally,
even in a case where the protruding amount E is 15 mm, the descending speed VW
decreases similarly to a case where the protruding amount E is 10 mm.
In FIG. 10, the descending speed VL at the tip faces Rl of the protrusions 12 of
the shaft stave 10 falls below the average descending speed VOl in a case where the
20 spacing D between the protrusions 12 is equal to or less than 80 mm, and becomes a
sufficiently small value in a range where the spacing D is 20 to 70 m. The spacing D
between the protrusions 12 particularly when the descending speed VL is a minimum
speed is 30 mm, and the descending speed becomes the smallest value at 25 to 35 mm
that is 30 mm ± 5 mm. Additionally, even in a case where the protruding amount E is
25 15mm, the descending speed is the same descending speed VL as that in cases where the
21,
protruding amount E is 5 mm and 10 mm.
That is, even in a case where the protruding amount E is 15 mm, a suitable
deposition layer can be formed inside the blast furnace 1. Accordingly, if the protruding
amount E is equal to or less than 15 mm even if the protruding amount is equal to or
5 more than 10 mm, the self-running effect can be obtained, deposition can be properly
maintained, and low thermal load, low fuel, and stable operation are easily achieved.
As a result, it is possible to significantly extend the lifespan of the blast furnace 1.
It can be said from the above that it is desirable that, if the test results based on
the 1/10 model are converted for an actual furnace, each spacing, D between the
10 protrusions 12 in arranging the protrusions 12 of the shaft stave 10 be within the range of
200 to 700 mm, and more preferably within the range of 250 to 350 mm.
[0040]
According to the present embodiment described above, the following effects are
obtained.
15 In the shaft stave 10, the furnace inner surface of the blast furnace 1 is
configured such that the planar surface 13 of the stave body 11 is the reference plane R.
Thus, the charging material 4 that descends inside the blast furnace 1 is decelerated, and
the stagnation layers 19 and 18 are formed along the reference plane R. Thereby, the
relative velocity with respect to the reference plane R of the stagnation layers 19 and 18
20 becomes small, and mechanical wear of the reference plane R caused by the particles of
the charging material 4 is relieved in the stave body 11. Accordingly, sufficient
durability is obtained even in the granular charging material that descends as the lumpy
zone 4A from the upper part to the middle part in the shaft section S2 by arranging the
stave of the present embodiment in the shaft section S2 that is the part exposed to the
25 granular charging material that descends inside the blast furnace 1.
22
[0041]
By setting the mutual spacing D between the protrusions 12 to 200 to 700 mm,
the stagnation layers 19 and 18 are easily formed along the reference plane Ron the
charging material 4 that is general in the current situation, that is, the ore-based charging
5 material with a particle size of about 8 to 25 nun and the coke-based charging material
with a particle size of about 20 to 55 mm that are alternately charged. Thereby, the
descending speed VW in the reference plane R can be reduced, the descending speed VL
of the particles of the charging material 4 at the tip of the protrusions 12 can be
suppressed, and the wear-mitigating effects of the whole shaft stave 10 can be brought
10 into the best state.
[0042]
Since the surfaces of the protrusions 12 are coated with a material with high
hardness, wear of the protrusions 12 themselves can be prevented. Accordingly, the
wear-relieving effects of the stagnation layers 19 and 18 derived by the protrusions 12
15 and the reference plane R based on these can be stably maintained for a long period of
time.
Since the protrusions 12 are formed integrally with the stave body 11,
manufacture is easy, and working for allowing the cooling conduits 17 to pass through
the protrusions 12 can be simply performed.
20 [0043]
Additionally, although the stave body 11 is made of copper or a copper alloy in
the shaft stave 10 of the present embodiment, the stave body may not be necessarily
made of copper or a copper alloy. Since the coolig efficiency as the shaft stave 10 can
be enhanced by making the stave body 11 of copper or a copper alloy, this is preferable.
25 By forming a stave made of copper or a copper alloy, cooling capability is high, whereas
23
the wear caused by the particles of the charging material 4 is readily received. However,
in the present embodiment, the wear can be mitigated by the stagnation layers 19 and 18.
This can maintain high cooling capability for a long period of time.
Since the conduits 16 are provided at the stave body 11 and the conduits 17 are
5 provided also at the protrusions 17, the cooling of the protrusions 12 can maintain the
hardness of the surfaces of the protrusions 12 high and maintain the wear-preventing
effects for a long period of time.
[0044]
In the present embodiment, the blast furnace 1 can enhance wear resistance by
10 using the shaft stave 10 based on the present embodiment as the shaft stave 2B.
Particularly, since the shaft stave 10 based on the invention is installed as the
stave 2B of the region S7 where the charging material 4 descends as the lumpy zone 4A
as being granular in the shaft section S2 of the blast furnace 1, Even if there is any
charging material 4 that descends as being granular, the stagnation layers 19 and 18 are
15 formed by the protrusions 12 of the shaft stave 10, and the wear from the reference plane
R is reduced.
[0045]
In the shaft section S2, progress of the wear caused by the granular charging
material 4 causes difficulty of an operation as the blast furnace 1. However, in the
20 present embodiment, the wear-resistant shaft stave 10 is installed at this portion. Thus,
the operation of the blast furnace 1 can be stably performed for a long period of time, and
the lifespan of the blast furnace can be extended. In the blast furnace 1, the protrusions
12 of the shaft stave 10 arranged within the blast furnace 1 are continuous at the whole
circumference in the furnace circumferential direction, circumferential balance within the
25 blast furnace 1 can be suitably maintained, and the operation of the blast furnace 1 can be
24
favorably maintained.
[0046]
(Second Embodiment)
A second embodiment of the invention is shown in FIGS. 11, 12, and 13. A
5 shaft stave 20 of the present embodiment is used as the shaft stave 2B in the blast furnace
1 of the aforementioned first embodiment. The configuration of the blast furnace 1 is
the same as that of the aforementioned first embodiment, and the shaft stave 20 of the
present embodiment is the same as the shaft stave 10 of the aforementioned first
embodiment in terms of basic configuration. Accordingly, description is omitted
10 regarding common portions with the stave 10 of the aforementioned first embodiment,
and different portions will be described below.
[0047]
In FIGS. 11, 12, and 13, the shaft stave 20 has the same the stave body 11, bolt
receiving portion 11A, protrusions 12, planar surface 13, refractory brick 15, conduits 16,
15 and connection ports 16A as those of the shaft stave 10 of the aforementioned first
embodiment. However, the conduits 17 and its connection ports 17A formed inside the
protrusions 12 in the shaft stave 10 of the first embodiment are omitted.
[0048]
In such a present embodiment, effects equivalent to those of the aforementioned
20 first embodiment can be obtained. However, since there are no conduits 17 formed
inside the protrusions 12, local cooling of the protrusions 12 is not obtained.
In this respect, local cooling of the protrusions 12 of the shaft stave 10 of the
aforementioned first embodiment is obtained. Thereby, since the durability of the
protrusions 12 can be maintained high, the shaft stave is optimal for a part that is high
25 load in terms of heat or wear within the blast furnace 1. On the other hand, it can be
25
said that the structure is simplified and manufacturing costs can also be reduced by an
amount saved by not providing the conduits 17, and the shaft stave 20 of the present
embodiment is more preferable in a part where load is not as necessary in terms of the
heat or wear of the protrusions 12.
5 [0049]
(Third Embodiment)
A third embodiment of the invention is shown in FIGS. 14, 15, and 16.
A shaft stave 30 of the present embodiment is used as the shaft stave 2B in the
blast ftirnace 1 of the aforementioned first embodiment. The configuration of the blast
10 furnace 1 is the same as that of the first embodiment, and the stave 30 of the present
embodiment is the same as the shaft stave 10 of the first embodiment in terms of basic
configuration. Accordingly, description is omitted regarding common portions of the
shaft stave 10 of the first embodiment, and different portions will be described below.
[0050]
15 In FIGS. 14, 15, and 16, the shaft stave 30 has the same the stave body 11, bolt
receiving portion 11A, planar surface 13, refractory brick 15, conduits 16, and connection
ports 16A as those of the shaft stave 10 of the first embodiment. However, the shaft
stave 30 of the present embodiment the protrusions 12 are not integral with the stave
body 11 unlike the shaft stave 10 of the first embodiment, and differs from the conduits
20 17 and the connection ports 17A of the protrusions 12 inside of the first embodiment.
That is, protrusions 32 and internal conduits 37 that are separate from the stave body 11
are provided.
[0051]
It is preferable that the protrusions 32 of the shaft stave 30 be bar-shaped blocks
25 molded from a material with high hardness, such as TiN, TiC, WC, and Ti-Al-N series.
26
The blocks may be formed of copper or a copper alloy or other materials, and the
surfaces thereof may be coated with a material with high hardness, such as TiN, TiC, WC,
and Ti-Al-N systems.
Grooves (recesses) 32A are formed in the planar surface 13 that becomes the
5 reference plane R of the stave body 11, and the aforementioned protrusions 32 are fitted
into the grooves 32A. This configuration allows the protrusions 32 to protrude from the
reference plane R.
[0052]
The conduits 37 are passed through some protrusions 32. As for the
10 protrusions 32 formed with the conduits 37, intermediate portions of the conduits 37, as
shown in FIG 16, are fixed by bolts 32C screwed in from the back face side (the outside
of the blast furnace 1) of the stave body 11, and both ends of the conduits 37 are fixed by
the connection ports 37A of the conduits that are screwed in similarly.
As shown in FIGS. 14 and 15, bolts 32B are thrust into the other protrusions 32
15 from the inside of the blast furnace 1, and, thereby, fixation of the protrusions 32 is
performed.
In addition, in a state where the protrusions are fitted into the stave body 11, the
spacing D, protruding amount E, and thickness T of the protrusions 32 are the same as
those of the aforementioned first embodiment.
20 [0053]
In such a present embodiment, effects equivalent to those of the aforementioned
first embodiment can be obtained.
Moreover, in the present embodiment, the protrusions 32 of the shaft stave 30
and the stave body 11 are separate. Therefore, the protrusions 32 of a material with
25 high hardness different from the stave body 11 can be simply formed, and the wear
27
resistance of the protrusions 32 can also be further enhanced.
[0054]
(Fourth Embodiment)
A fourth embodiment of the invention is shown in FIGS. 17, 18, and 19.
5 A shaft stave 40 of the present embodiment is used as the shaft stave 2B in the
blast furnace 1 of the aforementioned first embodiment. The configuration of the blast
furnace 1 is the same as that of the first embodiment, and the shaft stave 40 of the present
embodiment is the same as the shaft stave 10 of the first embodiment in terms of basic
configuration. Accordingly, description is omitted regarding common portions of the
10 shaft stave 10 of the first embodiment, and different portions will be described below.
[0055]
In FIGS. 17, 18, and 19, the shaft stave 40 has the same the stave body 11, bolt
receiving portion 11 A, planar surface 13, refractory brick 15, conduits 16, and connection
ports 16A as those of the shaft stave 10 of the first embodiment. However, instead of
15 the protrusions 12 integral with the stave body 11 in the shaft stave 10 of the first
embodiment, the protrusions 32 that are separate from the same stave body 11 as the
aforementioned third embodiment are provided. Here, in the present embodiment, there
are no internal conduits 37 and the internal connection ports 37A of the protrusions 32,
and all the protrusions 32 are fixed by the bolts 32C screwed in from the back side of the
20 stave body 11.
[00,56]
In such a present embodiment, effects equivalent to those of the aforementioned
third embodiment can be obtained. However, since there are no conduits 37 formed
inside the protrusions 32 of the shaft stave 40, local cooling of the protrusions 32 is not
25 obtained.
28
In this respect, local cooling of the protrusions 32 of the shaft stave 30 of the
aforementioned third embodiment is obtained. Thereby, since the durability of the
protrusions 32 can be maintained high, the shaft stave is optimal for a region that is high
load in terms of heat or wear within the blast furnace 1. On the other hand, it can be
5 said that structure is simple and manufacturing costs can also be reduced, as much as the
conduits 37 are not provided, and the shaft stave 40 of the present embodiment is more
preferable in a part where load is not required so much in terms of the heat or wear of the
protrusions 32.
[0057]
10 (Modification)
In addition, the invention is not limited to the aforementioned embodiments, but
includes modifications within a range that the object of the invention can be achieved.
When the staves 10 to 40 are arranged within the blast furnace I in the
embodiments, the protrusions 12 and 32 of each of the shaft staves 10 to 40 are
15 continuously annular in the furnace circumferential direction within the blast furnace 1.
However, the protrusions may be mutually non-continuous annular, may be arranged in
zigzag at different heights, or may be sequentially changed in height or spirally arranged.
However, circumferential balance is important in terms of the operation of the blast
furnace 1; and consideration should be made so that a symmetric property is obtained
20 with respect to the center of the blast furnace 1.
[0058]
In the embodiments, the surfaces of the protrusions 12 of the shaft stave 10 to 40
are coated with a material with high hardness or the protrusions 32 themselves are
molded from a material with high hardness. However, use of the high-hardness material
25 is not essential. However, since the protrusions protrude from the reference plane R of
29
the stave body 11 of the shaft staves 10 to 40 and are easily worn by the charging
material 4, it is desirable to secure wear resistance using the high-hardness material.
In addition, the arrangement, cross-sectional shape, and the arrangement of
conduits 16 and 17 of the protrusions 12, and the overall shape, dimensions, or the like of
5 the shaft staves 10 to 40 may be appropriately selected depending on embodiments.
Description of the Reference Symbols
[0059]
1: BLAST FURNACE
10 2: FURNACE BODY
2A: SHELL
2B,2C: STAVE
2D, 2E: HEAT-RESISTANT BRICK
3: GAS TRAP MANTEL
15 4: CHARGING MATERIAL
4A: LUMPY ZONE
4B: COHESIVE ZONE
4C: DROPPING ZONE
4D: FURNACE CORE
20 5: TUYERE
SA: HOT BLAST
5B: RACEWAY
6: TAP HOLE
6A: IRON
25 6B: HOT METAL
30
10T040: SHAFT STAVE
11: STAVEBODY
11A: BOLT RECEIVING PORTION
12,32: PROTRUSION
5 13: PLANAR SURFACE
15: REFRACTORY BRICK
16, 17, 37..: COOLING CONDUIT
16A, 17A, 37A: CONNECTION PORT
19, 18: STAGNATION LAYER
10 32A: GROOVE
32B, 32C: BOLT
B: BOUNDARY
D: SPACING
E: PROTRUDING AMOUNT
15 R: REFERENCE PLANE
RI: TIP FACE
S I: FURNACE THROAT SECTION
S2: SHAFT SECTION
S3: FURNACE BELLY SECTION
20 S4: BOSH SECTION
S6: FURNACE BOTTOM SECTION
S7: INSTALLATION PART OF SHAFT S [AVE
S8: INSTALLATION REGION OF BOSH STAVE
VOl TO V05: AVERAGE DESCENDING SPEED
25 V1 TO V5: DESCENDING SPEED
31
VL TO VLS: DESCENDING SPEED AT TIPS OF PROTRUSIONS
VW TO VW3:° DESCENDING SPEED AT REFERENCE PLANE
32,
CLAIMS
1. A stave provided on an inner periphery of a shaft section of a blast furnace,
the stave comprising:
5 a stave body having a reference plane facing an internal space of the blast
furnace; and
a plurality, of protrusions that protrudes from the reference plane toward an inner
side of the blast furnace.
10 2. The stave according to Claim 1,
wherein a protruding dimension of the protrusions is 50 to 150 mm, and
a spacing between adjacent protrusions is 200 to 700 mm.
3. The stave according to Claim 1,
15 wherein the protrusions are continuously or intermittently provided along a
circumferential direction of the blast furnace.
4. The stave according to Claim 1,
wherein surfaces of the protrusions are formed of a material with high hardness.
20
5. The stave according to Claim 4,
wherein the stave body is formed with recesses,
the protrusions are a block embedded in the recesses and protrudes from the
reference plane, and
25 the block is formed of the material with high hardness.
33
6. The stave according toClaim 4,
wherein the protrusions are formed integrally with the stave body.
5 7. The stave according to Claim 1,
wherein the stave body is a copper or a copper alloy.
8. The stave according to Claim 1,
wherein conduits that cool the protrusions are provided inside the protrusions.
10
9. The stave according to Claim 1,
wherein an angle, which is formed between a lower lateral face of the protrusion
on two lateral faces of the protrusion on both end sides of the reference plane, and the
reference plane, is less than 90 degrees.
15
10. A blast fur`naee comprising the stave according to any one of Claims 1; to 9.