JP5308224B2 - Dust catcher for blast furnace gas - Google Patents

Description

  The present invention relates to a dust catcher for blast furnace gas that separates dust from gas containing dust discharged from a blast furnace.

  The gas discharged from the blast furnace is used as combustion gas in the steelworks, but the blast furnace gas cannot be used as it is because it contains dust scattered from the charged raw materials. It is used as a heat source for heating furnaces and boilers after being cleaned by a gas cleaning system. In the gas cleaning system, a dust catcher is arranged as a facility for roughly collecting dust in the gas discharged from the blast furnace.

  FIG. 6 is a view showing the arrangement of blast furnaces and dust catchers.

  In FIG. 6, the gas containing dust generated in the blast furnace 15 is introduced into the dust catcher 17 through the curved pipe 18 connecting the duct 16 at the top of the blast furnace 15 and the gas introduction pipe 8 of the dust catcher 17. Are separated.

  For the purpose of improving the dust collection efficiency of the dust catcher, as disclosed in Patent Document 1, a swirl flow is given to the gas exiting the expansion tube by a cyclone at a plurality of locations around the inside of the dust catcher container. There is known a dust catcher that captures dust of medium particles and fine particles entrained in a gas flow by a flow (see Patent Document 1).

  FIG. 7A is a longitudinal sectional view of a conventional dust catcher for a blast furnace gas provided with a cyclone in the container, and FIG. 7B is a sectional view taken along line AA in FIG.

  In FIG. 7, the container 1 of the dust catcher has a cylindrical body 2 at the center and conical cylinders 3 and 4 integrally connected to the upper and lower parts thereof, respectively. A gas discharge pipe 5 through which the gas from which the dust is separated is discharged is connected to the upper conical cylinder 3. The gas discharge pipe 5 is connected to a processing apparatus such as a scrubber downstream thereof. The lower cone-shaped cylinder 4 accumulates dust 6 that is separated from the gas and descends. A valve 7 for discharging the accumulated dust 6 is provided at the bottom of the lower conical cylinder 4.

  From the upper conical cylinder 3 to the center of the inside of the cylindrical body 2, the gas diameter from the blast furnace is expanded in the vertical direction following the gas introduction pipe 8 into which the gas from the blast furnace is introduced from the outside of the upper conical cylinder 3. A gradually expanding expansion tube 9 is integrally connected. The gas from the blast furnace introduced from the gas introduction pipe 8 flows out from the opening at the lower end through the expansion pipe 9.

  On the inner periphery of the cylindrical body 2, a plurality of cyclones 11 are supported and fixed at intervals by an expansion tube 9, a partition plate 10 fixed to the cylindrical body 2, and a wall of the cylindrical body 2. In FIG. 5, four cyclones 11 are provided at equal intervals. The cyclone 11 is a conventionally known dust collector that separates solid and gas by a swirling flow using centrifugal force. The partition plate 10 is a plate for partitioning a region where dust is separated from gas and a region where gas from which dust is separated flows out. The lower side of the partition plate 10 is provided with a lower cylindrical body 2 provided with a cyclone 11 for separating coarse particles from the gas that has flowed out of the expansion tube 9 and separating medium particles and fine particles from the gas from which the coarse particles have been separated. The upper side of the partition plate 10 is an area of the upper conical cylinder 3 in which the gas outflow pipe 13 of the cyclone 11 for discharging the gas from which the dust is separated is opened.

  A coarse particle separation gas introduction pipe 12 is connected to the upper part of the cyclone 11 in the tangential direction of the cyclone 11. A gas that flows out from the opening at the bottom of the expansion tube 9 and from which coarse particles are separated is introduced into the cyclone 11 in a tangential direction. At the center of the cyclone 11, a gas outflow pipe 13 through which the gas separated from the dust of medium particles and fine particles flows out to the upper conical cylinder 3 protrudes from the partition plate 10 and opens.

  The lower part of the cyclone 11 is connected to a dust discharge duct 14 that discharges dust and communicates with the outside of the container 1.

  Next, the operation of the dust catcher will be described.

  In FIG. 7, gas containing dust discharged from the blast furnace enters the expansion pipe 9 through the gas introduction pipe 8, moves downward, and flows out from the opening of the expansion pipe 9. The outflowed gas is reversed upward. At this time, the dust of coarse particles and particles having a large mass contained in the gas is separated from the gas flow by gravity sedimentation and descends and accumulates in the lower conical cylinder 4. To go.

  The gas from which the coarse particles are separated is reversed upward and rises, and is introduced from the coarse particle separation gas introduction pipe 12 into the cyclone 11 in the tangential direction.

  The gas introduced into the cyclone 11 in the tangential direction becomes a swirl flow, and the dust of medium particles and fine particles is separated and descends and accumulates in the lower part. The gas from which the dust has been separated passes through the gas outflow pipe 13 in the cyclone 11 and is discharged from the discharge pipe 5 through the upper conical cylinder 3. Dust accumulated in the lower part of the cyclone 11 is discharged out of the container 1 from the dust discharge duct 14.

Japanese Patent Laid-Open No. 55-21545

  In the conventional dust catcher, the optimal planar arrangement of a plurality of cyclones arranged in a container is not disclosed. Further, the dust discharge pipe 14 was exhausted from the blast furnace flowing out from the gas introduction pipe 8 and was orthogonal to the flow of gas containing dust discharged from the blast furnace, so that the wear was severe.

  Therefore, the present invention reduces the wear of the cyclone caused by the dust in the dust catcher that separates the dust from the gas containing the dust discharged from the blast furnace, and the optimum plane arrangement of the cyclone arranged in the dust catcher. A dust catcher for blast furnace gas is provided.

  In the present invention, an expansion pipe into which a gas containing dust discharged from the blast furnace is introduced is disposed in a blast furnace gas dust catcher container connected to a duct at the top of the blast furnace and a curved pipe. A plurality of cyclones are disposed around the inner wall of the container, and a gas discharge pipe for discharging the gas from which dust is separated in the container is provided at the upper part of the container. A partition plate for partitioning the container up and down is provided between the peripheries, and the inside of the container is separated from the gas flowing out from the expansion tube at the lower side of the partition plate by the cyclone and the cyclone on the upper side of the partition plate In a dust catcher for blast furnace gas that is partitioned into a region where the gas from which dust is separated is discharged to the discharge pipe, the gas introduced from the bent pipe is a cyclone disposed on the inner wall of the container. Characterized by being arranged at a position except for the position of the side of drift in a large tube.

  The said structure WHEREIN: You may arrange | position the coarse particle separation gas introduction pipe | tube which introduce | transduces gas to the tangential direction of a cyclone in the position on the opposite side on both sides of the said opposing cyclone.

  Further, in the above configuration, an annular dust re-scattering prevention plate inscribed in a lower part of the side surface of each cyclone may be formed below the expansion pipe in the container, spaced apart from the wall of the container.

  Moreover, you may provide the discharge port of the dust captured by each said cyclone outside the system of a dust catcher for every cyclone.

  The present invention pays attention to the fact that the gas flow velocity becomes high at a position opposed to the blast furnace due to the influence of the bent pipe 18 connecting the blast furnace and the dust catcher found by various preliminary tests by the inventors. Since the cyclone is not arranged on the side, the distance until the high-speed gas is introduced into the cyclone coarse separation gas introduction pipe is long, so the gas is discharged from the expansion pipe and is introduced into the coarse separation gas introduction pipe. Since the residence time becomes longer, coarse particle separation by gravity settling is strengthened, and the overall dust removal rate is improved. In addition, high-speed gas containing a large amount of coarse particles can be prevented from flowing into the cyclone, and the speed of the processing gas flowing into the cyclone can be suppressed, so that wear due to cyclone particles is extremely reduced. As a result, maintenance work is reduced compared to conventional dust catchers.

  Further, in the present invention, the high-speed gas is introduced into the coarse-grain separation gas introduction pipe by providing an inlet of the coarse-grain separation gas introduction pipe for introducing the gas into the cyclone on the side opposite to the direction in which the high-speed gas flows. Can be further increased, and the effect of improving the dust removal rate and the effect of reducing wear can be further improved.

  Further, in the present invention, by forming an annular dust re-scattering prevention plate, the dust of medium particles and fine particles that are separated from the gas by the cyclone and descend in the container are re-scattered and passed through the gas discharge pipe 5 to follow. It can prevent being accompanied by gas.

  Further, by providing a dust discharge port for each cyclone outside the dust catcher system for each cyclone, coarse dust that is mainly removed via the gas introduction pipe 8 and mainly dust that is removed by the cyclone. When the utilization method of particles and fine particle dust is different, they can be collected separately, and the dust discharge duct is not orthogonal to the flow of gas containing dust flowing out from the gas introduction pipe as in the cited reference 1, so that dust discharge Abrasion due to duct particles is drastically reduced. As a result, maintenance work is reduced compared to conventional dust catchers.

(A) is a longitudinal cross-sectional view of the dust catcher of this invention, (b) is sectional drawing of the AA line of (a). It is a figure which shows the flow of the gas introduced into the gas introduction pipe and the expansion pipe from the curved pipe. It is a figure which shows arrangement | positioning of a curved pipe and a cyclone. It is a figure of another Example of the dust catcher of this invention. It is a figure of another Example of the dust catcher of this invention. It is a figure which shows arrangement | positioning of a blast furnace and a dust catcher. The conventional dust catcher is shown, (a) is a longitudinal cross-sectional view, (b) is a BB line sectional view of (a).

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1A is a longitudinal sectional view of a blast furnace gas dust catcher according to the present invention, and FIG. 1B is a sectional view taken along line AA in FIG.

  In FIG. 1, a dust catcher container 1 has a cylindrical body 2 at the center and conical cylinders 3 and 4 integrally connected to an upper part and a lower part thereof, respectively. A gas discharge pipe 5 through which the gas from which the dust is separated is discharged is connected to the upper conical cylinder 3. The gas discharge pipe 5 is connected to the next processing apparatus such as a scrubber. The lower cone-shaped cylinder 4 accumulates dust 6 that is separated from the gas and descends. A valve 7 for discharging the accumulated dust 6 is provided at the bottom of the lower conical cylinder 4.

  From the upper conical cylinder 3 to the center of the inside of the cylindrical body 2, the gas diameter from the blast furnace is expanded in the vertical direction following the gas introduction pipe 8 into which the gas from the blast furnace is introduced from the outside of the upper conical cylinder 3. A gradually expanding expansion tube 9 is integrally connected. The gas from the blast furnace introduced from the gas introduction pipe 8 flows out from the opening at the lower end through the expansion pipe 9.

  On the inner periphery of the cylindrical body 2, a plurality of cyclones 11 are supported at intervals by the expansion tube 9, the partition plate 10 fixed to the cylindrical body 2, and the wall of the cylindrical body 2. In FIG. 4, four cyclones 11 are provided at equal intervals. The cyclone 11 is a conventionally known dust collector that separates solid and gas by a swirling flow using centrifugal force. The cyclone 11 is provided with a coarse separation gas introduction pipe 12 for flowing out from the opening at the bottom of the expansion pipe 9 and introducing the gas from which coarse particles are separated in the tangential direction of the cyclone 11. At the center of the cyclone 11, an outflow pipe 13 through which the gas separated from the dust of medium particles and fine particles flows out to the upper conical cylinder 3 protrudes from the partition plate 10 and opens.

  The partition plate 10 is a plate that divides a region where dust is separated from gas and a region where gas from which dust is separated flows out. In this embodiment, the lower side of the partition plate 10 is provided with a lower cylindrical body 2 provided with a cyclone 11 that separates coarse particles from the gas that has flowed out of the expansion tube 9 and separates coarse particles from the lower gas. The upper side of the partition plate 10 is an area of the upper conical cylinder 3 in which the gas outflow pipe 13 is opened for the cyclone 11 for discharging the gas from which the dust is separated.

  FIG. 2 is a diagram showing the flow of gas introduced from the curved pipe into the gas introduction pipe and the expansion pipe.

  As shown in FIG. 6, the pipe connected between the top of the blast furnace and the gas inlet pipe 8 of the dust catcher is arranged in a plane so that the top of the blast furnace and the dust catcher are arranged in a plane. A tube 18 is formed. Therefore, the gas introduced from the curved pipe drifts to the high-speed gas region 22 on the side of the gas introduction pipe 8 and the expansion pipe 9 that opposes the blast furnace, and the gas flow speed on the side of the expansion pipe 9 that has drifted is high. found. For this reason, the coarse particle separation by gravity sedimentation on the drifted side is insufficient, and the cyclone 11 is exposed to a high-speed gas containing dust of coarse particles, medium particles, and fine particles due to an increase in the gas flow velocity. The phenomenon of large wear has occurred.

  In order to sufficiently perform coarse grain separation by gravity sedimentation and to prevent the cyclone 11 from being worn under the influence of the high-speed gas flow, the cyclone 11 is not exposed to the high-speed gas flowing out from the expansion tube 9. Further, high-speed gas is prevented from being introduced into the coarse separation gas introduction pipe 12 of the cyclone 11. A plurality of cyclones are arranged at positions excluding the side where the gas introduced from the curved pipe 18 drifts in the expansion pipe 9.

  In FIG. 3 showing the relationship between the arrangement of the curved pipe and the cyclone, in FIG. 3 (a), since the cyclone is on the side of the drift, the residence time from the high-speed gas spreading pipe outflow to the arrival of the coarse separation gas introduction pipe However, the cyclone 11 is not properly placed because the cyclone 11 is exposed to and worn out. On the other hand, FIG. 3B is arranged so that the high-speed gas flowing out from the expansion tube 9 is not exposed to the cyclone 11, so that coarse grain separation is enhanced and cyclone wear can be reduced. it can. In FIG. 3 (c), since the high-speed gas is directed in a direction in which the high-speed gas is not introduced into the coarse separation gas introduction pipe 12 of the cyclone 11, the coarse separation is further strengthened and the cyclone wear can be reduced. FIG. 3D shows an example in which a range where the cyclone 11 is not arranged is wide in order to cope with a wide high-speed gas region.

  Next, the operation of the dust catcher will be described.

  A gas containing dust discharged from the blast furnace enters the expansion pipe 9 through the gas introduction pipe 8, moves downward, and flows out from the opening of the expansion pipe 9. The outflowed gas is reversed upward. At this time, the dust of coarse particles and particles having a large mass contained in the gas is separated from the gas flow by gravity sedimentation and descends and accumulates in the lower conical cylinder 4. To go.

  The gas from which the coarse particles are separated is reversed upward and rises, and is introduced from the coarse particle separation gas introduction pipe 12 into the cyclone 11 in the tangential direction.

  The gas introduced into the cyclone 11 in the tangential direction becomes a swirl flow, and the dust of medium particles and fine particles is separated and descends, and accumulates at the bottom of the lower conical cylinder 4. The gas from which the dust has been separated passes through the outflow pipe 13 in the cyclone 11 and is discharged to the discharge pipe 5 through the upper conical cylinder 3 and sent to the next processing apparatus such as a scrubber.

  The cyclone 11 is arranged at a position excluding the side where the coarse particle separation gas introduction pipe 12 is drifted by the expansion pipe 9 so as not to be directly affected by the high-speed drifted gas flow, thereby strengthening the coarse grain separation. At the same time, it is possible to prevent the cyclone from being worn.

  FIG. 4 is a diagram of another embodiment of the dust catcher of the present invention. The same members as those in the dust catcher shown in FIG.

  In the present embodiment, as in the first embodiment, the cyclone 11 is located at a position excluding the side where the coarse particle separation gas introduction pipe 12 of the cyclone 11 is drifted by the expansion pipe 9 so as not to be directly affected by the high-speed gas flow. To place.

  Further, an annular dust re-scattering prevention plate 19 inscribed in the lower part of the side surface of each cyclone 11 is formed below the expansion tube 9. The dust re-scattering plate 19 is formed so as to expand downward.

  By disposing the dust re-scattering plate 19, the dust of medium particles and fine particles descending from the lower conical cylinder 4 separated from the gas by the cyclone 11 is entrained by the gas that rises out of the expansion tube 9. To prevent re-scattering.

  FIG. 5 is a diagram of another embodiment of the dust catcher of the present invention. The same members as those of the dust catcher shown in FIGS. 1 and 4 are denoted by the same reference numerals, and the description thereof is omitted.

  In the present embodiment, as in the first embodiment, the cyclone 11 is located at a position excluding the side where the coarse particle separation gas introduction pipe 12 of the cyclone 11 is drifted by the expansion pipe 9 so as not to be directly affected by the high-speed gas flow. To place.

  Furthermore, in this embodiment, the dust captured by each cyclone 11 is guided out of the dust catcher system by the discharge port 20, and a valve 21 is provided at the lower end of the discharge port 20.

  As dust captured from blast furnace gas, the main components of coarse dust are iron powder and coal powder, and these are reused, for example, as iron-making raw materials. On the other hand, since the dust of medium particle and fine particle cannot be used as a raw material for iron making because of a high content of zinc and lead, they are reused as an auxiliary material of blast furnace cement after firing, for example. In other words, the reuse destination varies depending on the particle size (type) of the captured dust.

  In the present invention, since it is configured as described above, the dust captured by the dust catcher is coarse dust, while the dust captured by the cyclone is medium particle and fine particle dust. Since they are not mixed after capture, in the case of reuse, the two can be used immediately without being separated.

  Further, since the cyclone 11 is provided outside the dust catcher system and the dust discharge duct is not traversed in the container, wear due to gas containing dust is reduced.

1: Container 2: Cylindrical body 3: Upper conical cylinder 4: Lower conical cylinder 5: Gas discharge pipe 6: Dust 7: Valve 8: Gas introduction pipe 9: Expansion pipe 10: Partition plate 11: Cyclone 12 : Coarse-grain separation gas introduction pipe 13: Gas outflow pipe 14: Dust discharge duct 15: Blast furnace 16: Duct 17: Dust catcher 18: Curved pipe 19: Dust re-scattering plate 20: Discharge port 21: Valve 22: High-speed gas region

Claims (4)

An expansion pipe into which gas containing dust discharged from the blast furnace is introduced is disposed in a blast furnace gas dust catcher container connected by a bent pipe and a duct at the top of the blast furnace. A plurality of cyclones are disposed on the inner wall of the container, and a gas discharge pipe for discharging the gas from which dust has been separated in the container is provided at the upper part of the container, and between the upper outer periphery of the expansion pipe and the inner periphery of the container A partition plate for partitioning the container up and down is provided, and the inside of the container separates the dust by the cyclone from the gas flowing out from the expansion tube below the partition plate, and the cyclone is separated by the cyclone above the partition plate. In the dust catcher for blast furnace gas, which is partitioned into a region for discharging the discharged gas to the discharge pipe,
A dust catcher for a blast furnace gas, characterized in that a cyclone disposed on the inner wall of the container is disposed at a position excluding a position where a gas introduced from a curved pipe is drifted by an expansion pipe.   The dust catcher for blast furnace gas according to claim 1, wherein an inlet of a coarse separation gas introduction pipe for introducing gas into the cyclone is provided on the opposite side of the direction in which the high-speed gas flows.   The annular dust re-scattering prevention plate inscribed in the lower part of the side surface of each cyclone is formed below the expansion pipe in the container at a distance from the wall of the container. Dust catcher for blast furnace gas.   The dust catcher for blast furnace gas according to claim 1 or 2, wherein a discharge port for dust captured by each of the cyclones is provided outside the system of the dust catcher.

Images