JP7424400B2 - Cyclone dust collector - Google Patents

Description

The present invention relates to a cyclone dust collector that collects dust contained in a gas to be treated.

For example, in a vertical iron melting furnace such as a blast furnace, hot air is blown into the interior from tuyeres installed at the bottom of the furnace while iron sources and heat sources such as coke are alternately introduced in layers. . The air blown through the tuyeres reacts with the carbon in the coke and rises through the furnace while melting the iron source with the heat of combustion. The gas that has reached the vicinity of the top of the furnace is exhausted in a state containing dust consisting of coke and solid particles of various sizes generated from the refractories in the furnace. It is necessary to separate and collect dust, which is made up of solid particles, from the exhaust gas from blast furnaces, etc.

Conventionally, various methods have been used to separate solid particles from a gas to be treated, and a cyclone dust collector is known as one of them. A cyclone dust collector separates solid particles in the gas to be treated using centrifugal force by rotating the gas to be treated. Vertical and horizontal types of cyclone dust collectors are known. Among these, a horizontal cyclone dust collector with less pressure loss may be used depending on the properties of the gas to be treated, the installation environment, etc. (see, for example, Patent Documents 1 and 2).

Patent Document 1 discloses a horizontal cyclone dust collector that separates dust by moving the gas to be treated in the axial direction while rotating it in the circumferential direction of the internal space along the inner wall. When the gas to be treated swirls, solid particles in the gas to be treated collide with the inner wall part due to centrifugal force. At this time, the motion component of the solid particles that swirls along the inner wall (swirling motion component) and the motion component that moves in the axial direction (axial motion component) disappear, and the solid particles are separated from the gas to be treated. be done.

Patent Document 2 discloses a horizontal cyclone dust collector including a protrusion that protrudes from an inner wall toward the inside in the radial direction of the inner space and extends along the circumferential direction of the inner wall. ing.

Japanese Patent Application Publication No. 2008-6315 JP2011-218250A

However, in the case of the cyclone dust collectors disclosed in Patent Documents 1 and 2, it becomes difficult to separate dust having a small particle size (mass) from the gas to be treated. Therefore, there is a problem that the collection rate of fine dust in the cyclone dust collector becomes low.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a cyclone dust collector that can improve the collection rate of fine dust.

（θ＞０［ｄｅｇ］）
［４］ 前記ダスト分離部は、横方向へ延びるガス流路を有する本体部と、前記本体部の前記ガス流路内に設置され、前記被処理ガスを前記本体部の内壁に沿って旋回させながら横方向へ流動させる整流部材と、を備えた［１］乃至［３］のいずれかに記載のサイクロン集塵装置。 [1] A cyclone dust collector that collects dust from a gas to be treated,
a dust separation section that rotates the gas to be treated with a horizontal direction as a rotation axis and separates dust from the gas to be treated;
a dust recovery unit that is connected to an outlet side of the dust separation unit and collects the dust separated by swirling of the to-be-processed gas by the dust separation unit;
a gas recovery unit whose inlet side is installed within the dust recovery unit and recovers the to-be-treated gas from which the dust has been separated;
Equipped with
The dust collection section has a shape that is constricted so that the flow path becomes smaller along the rotation axis direction from the inlet side of the gas to be treated,
The dust separation unit is a cyclone dust collector that swirls the to-be-treated gas so that the amount of swirl of the to-be-treated gas is 75 [deg/m] or more.
[2] The dust collection section has a tapered shape with a taper angle θ [deg],
The cyclone dust collector according to [1], wherein the dust separation section swirls the to-be-treated gas so that η≧15×θ+45, where the amount of swirling of the to-be-treated gas is η [deg/m]. .
[3] The dust collection section has a tapered shape with a taper angle θ [deg],
The cyclone dust collector according to claim 1, wherein the dust separation section swirls the to-be-treated gas so that the following formula is satisfied, where the amount of swirling of the to-be-treated gas is η [deg/m].

(θ>0[deg])
[4] The dust separation section includes a main body having a gas flow path extending laterally, and is installed within the gas flow path of the main body, and swirls the gas to be treated along an inner wall of the main body. The cyclone dust collector according to any one of [1] to [3], further comprising: a rectifying member that causes the flow to flow laterally.

According to the cyclone dust collector according to the present invention, the dust collection section has a shape narrowed so that the flow path becomes smaller from the inlet side of the gas to be treated along the rotation axis direction, and the dust separation section By setting the amount of rotation η to 75 [deg/m] or more, it is possible to suppress minute dust from staying in the dust collection section and improve the recovery rate of minute dust.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the preferable embodiment of the cyclone dust collector of this invention. FIG. 2 is a schematic diagram showing an example of a dust separation section in the cyclone dust collector of FIG. 1. FIG. It is a schematic diagram which expanded a part of turning space part of a dust collection part. 2 is a graph showing the relationship between the amount of rotation η [deg/m] and pressure loss in the cyclone dust collector shown in FIG. 1. FIG. It is a graph which shows the relationship between the amount of rotation and the collection ratio of dust when the taper angle θ=0 [deg] without providing an inclination to the dust collection section. It is a graph showing the ratio of dust staying (swirling) and captured dust to the taper angle θ when the amount of swirling η=60 [deg/m]. It is a graph showing the ratio of dust staying (swirling) and captured dust to the taper angle θ when the amount of swirling η=75 [deg/m]. It is a graph showing the ratio of dust staying (swirling) and captured dust to the taper angle θ when the amount of swirling η=90 [deg/m]. It is a graph showing the ratio of dust staying (swirling) and captured dust to the taper angle θ when the amount of swirling η=120 [deg/m]. It is a graph showing the ratio of staying (swirling) dust and captured dust to the taper angle θ when the turning amount η=150 [deg/m]. It is a graph showing the ratio of the amount of dust DT collected when the taper angle θ=1 [deg] to the case where the taper angle θ=0 [deg]. It is a graph showing the relationship between the amount of rotation η and the maximum taper angle θmax at which the recovery amount becomes maximum at each amount of rotation η. It is a graph showing the relationship between the amount of rotation η and the maximum taper angle θmax at which the recovery amount becomes maximum at each amount of rotation η.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a preferred embodiment of the cyclone dust collector of the present invention. The cyclone dust collector 1 in FIG. 1 is a so-called horizontal cyclone dust collector that generates a swirling flow centered on the horizontal direction and collects dust DT from the gas to be treated TG. The cyclone dust collector 1 includes a dust separating section 3 that separates dust DT from the gas to be treated TG that flows in from an inflow pipe 2, a dust collecting section 4 that collects the dust DT separated by the dust separating section 3, and a dust collecting section 4 that collects the dust DT separated by the dust separating section 3. It includes a gas recovery section 5 that recovers the to-be-treated gas TG from which DT has been separated. In this embodiment, the inflow pipe 2 is connected to, for example, a blast furnace or a converter, and the gas to be treated TG is exhaust gas discharged from the blast furnace, converter, etc. (hereinafter also referred to as a blast furnace, etc.). An example is given below.

FIG. 2 is a schematic diagram showing an example of the dust separation section 3 in the cyclone dust collector 1 of FIG. 1. As shown in FIG. The dust separation unit 3 in FIG. 2 rotates the gas to be treated TG about the horizontal direction and separates the dust DT from the gas to be treated TG. The dust separation unit 3 includes a main body 3A having a gas flow path extending in the lateral direction, and is installed within the gas flow path of the main body 3A, and rotates the gas to be treated TG along the inner wall of the main body 3A. It includes a rectifying member 3B that is moved in the axial direction.

The main body portion 3A is a cylindrical body having a hollow portion serving as a gas flow path. The shape of the main body portion 3A may be, for example, a cylindrical shape or a truncated cone shape. The main body portion 3A in FIG. 1 has a truncated conical shape with an outlet diameter larger than an inlet diameter, and the gas flow path is an enlarged flow path whose diameter increases from the upstream side to the downstream side. The flow regulating member 3B is arranged within the hollow portion of the main body portion 3A. The rectifying member 3B has a rectifying plate 3C that rectifies the to-be-treated gas TG flowing from the inlet side of the main body 3A into a swirling flow. The current plate 3C is formed in a spiral shape to generate a swirling flow in a desired direction. In the present embodiment, the rectifying plate 3C is formed in a spiral shape (the lower end side is located in the traveling direction of the to-be-treated gas TG than the upper end side), which is clockwise in the traveling direction of the to-be-treated gas TG. The current plate 3C is provided on the outer peripheral side of the swirling flow, that is, on the inner wall surface of the main body 3A. Therefore, the rectifying member 3B turns the to-be-processed gas TG flowing into the main body 3A into a swirling flow that swirls around the swirling axis AL. At this time, the amount of rotation of the gas to be treated TG is determined by the pitch or inclination angle of the current plate 3C. The amount of swirling of the gas to be treated TG means the swirling angle [deg/m] around the rotating axis AL per unit length in the traveling direction when viewed from the rotating axis AL direction.

In particular, when the main body portion 3A has an enlarged flow path whose diameter increases from the upstream side to the downstream side, the to-be-treated gas TG becomes an enlarged swirl flow whose swirl diameter increases as it goes toward the downstream side (exit side). Then, the swirling flow of the gas to be treated TG becomes easier to separate from the rectifying plate 3C as it goes downstream, and can be made to swirl more easily along the inner wall of the main body 3A. Although FIG. 1 shows an example in which the main body portion 3A forms an enlarged tubular flow path, the present invention is not limited to this, and depending on the required performance, a cylindrical shape in which the inlet diameter and the outlet diameter are the same may be used. Alternatively, even if the diameter is narrowed from the inlet side to the outlet side, a swirling flow can be generated along the inner wall of the main body portion 3A.

The dust collection section 4 in FIG. 1 is connected to the outlet side of the dust separation section 3 and collects the dust DT separated by swirling of the gas TG to be treated in the dust separation section 3. The dust collection section 4 is formed into a tubular or cylindrical shape, for example, a bottomed cylindrical shape whose one end side has the same diameter as the exit diameter of the dust separation section 3 . The dust recovery section 4 includes a turning space 4A provided between the outlet of the dust separation section 3 and the inlet of the gas recovery section 5, and a dust shooter 4B provided at the bottom of the dust recovery section 4 for collecting dust DT. and has. The swirling gas TG flows into the swirling space 4A, and the dust DT collides with the inner wall of the swirling space 4A. Then, the dust shooter 4B collects the dust DT that has left the swirling flow.

FIG. 3 is an enlarged schematic diagram of a part of the turning space 4A of the dust collection section 4 (above the side connected to the dust separation section 3). As shown in FIGS. 1 and 3, the swirling space 4A of the dust recovery section 4 is narrowed so that the flow path becomes smaller from the inlet side of the gas to be treated TG to the inlet side of the gas recovery section 5. It has a shape. Then, the gas to be treated TG turns into an airflow flowing toward the gas recovery section 5 while being rotated by the dust recovery section 4 . In particular, the swirling space 4A of the dust recovery section 4 is preferably formed into a tapered shape having a predetermined taper angle θ that is an acute angle with respect to the traveling direction of the gas to be treated TG.

The gas recovery unit 5 in FIG. 1 is a pipe that recovers the gas to be processed TG from which the dust DT has been separated, and one end thereof is connected to a gas utilization side pipe (not shown). The gas recovery section 5 can have a smaller diameter than the outlet diameter of the dust separation section 3 and the dust recovery section 4, for example, and the inlet side (other end side) is inserted into the dust recovery section 4. At this time, the gas recovery section 5 is preferably arranged such that, for example, the central axis of the dust separation section 3, the central axis of the dust recovery section 4, and the central axis of the gas recovery section 5 coincide with each other. The inlet side (the other end side) is inserted into the dust collection section 4 so that the dust shooter 4B is located on the lower side.

An example of the operation of the cyclone dust collector 1 will be described with reference to FIGS. 1 and 2. A gas to be treated TG discharged from a blast furnace, a converter, or the like flows into the dust separation section 3 from the inlet side via an inflow pipe 2 . Then, the gas to be treated TG becomes an expanded swirling flow by the rectifier plate 3C of the dust separation section 3, and flows into the dust collection section 4. The dust DT contained in the gas to be processed TG collides with the inner wall of the main body 3A in the dust separation section 3 or the inner wall of the dust collection section 4 due to the swirling flow, and loses kinetic energy. Then, the dust DT separates from the swirling flow of the gas to be treated TG and is collected by the dust shooter 4B. On the other hand, the to-be-processed gas TG from which the dust DT has been separated is recovered from the gas recovery section 5 and flows into a usage-side pipe (not shown).

Here, the dust DT collected by the cyclone dust collector 1 of FIG. 1 includes solid particles of various sizes. The separation and collection limit particle diameter ds of solid particles in the cyclone dust collector 1 can be determined by the following equation (2).

ｄ_ｓ：分離捕集限界粒子径［ｍ］，
μ：流体粘性［Ｐａ・ｓ］，
ｒ_１：回転内径［ｍ］，
ｒ_２：回転外径［ｍ］，
Ｎ：回転数［－］，
ｖ_ｉ：速度［ｍ／ｓ］，
ρ_ｐ：粒子密度［ｋｇ／ｍ^３］，
ρ_ａ：流体密度［ｋｇ／ｍ^３］

_ds : Separation and collection limit particle size [m],
μ: Fluid viscosity [Pa・s],
r ₁ : Rotating inner diameter [m],
r ₂ : Rotating outer diameter [m],
N: Number of rotations [-],
v _i : velocity [m/s],
ρ _p : particle density [kg/m ³ ],
ρ _a : Fluid density [kg/m ³ ]

According to equation (2), the amount of dust collected can be increased by increasing the swirling motion component (swirling motion component). In order to reduce the diameter of separated and collected particles in order to collect fine solid particles, it is conceivable to increase the amount of swirl to increase the amount of dust DT collected. Note that the fine dust DT means solid particles having a density of 1000 kg/m ³ and a particle diameter of 100 μm or less. Further, the graphs shown in FIGS. 4 to 12 below are based on simulation results when the fine dust DT has a particle diameter of 75 μm, a Reynolds number Re of about 50,000, and a particle Reynolds number of about 100.

However, as the amount of rotation increases, the pressure loss increases. FIG. 4 is a graph showing the relationship between the amount of rotation η [deg/m] and pressure loss in the cyclone dust collector 1 shown in FIG. As shown in FIG. 4, as the amount of rotation increases, the pressure loss also increases significantly. As mentioned above, an advantage of the horizontal cyclone dust collector over the vertical cyclone dust collector is that the pressure loss is small. If the amount of rotation is increased, the pressure loss will increase, and the advantages of the horizontal cyclone dust collector cannot be fully utilized. Therefore, from the viewpoint of pressure loss, the amount of swirl η is preferably 150 [deg/m] or less, and if pressure loss is to be suppressed to 5000 [Pa] or less, it should be 140 [deg/m] or less. is even more preferable.

Furthermore, even if the swirling amount of the gas to be treated TG is increased in consideration of the pressure loss described above, the ability to collect fine dust DT will not increase. FIG. 5 is a graph showing the relationship between the amount of rotation and the collection ratio of dust DT when the dust collection section 4 is not tilted and the taper angle θ=0 [deg]. In FIG. 5, "recovery" means the proportion of minute dust collected by the dust shooter 4B, and "stay" means the proportion of minute dust that continues to swirl and stay in the dust collection section 4. "non-recovery" means the proportion of dust that has flowed out to the gas recovery section 5.

As shown in FIG. 5, the proportion of unrecovered minute dust DT flowing out to the gas recovery section 5 decreases as the amount of swirl increases. However, as the amount of rotation increases, the amount of fine dust DT that continues to rotate and stay in the fine dust collection section 4 also increases, and the amount of fine dust DT that is captured decreases. The minute dust DT that continues to swirl remains in the dust collection section 4. For this reason, the frequency of cleaning inside the dust collection section 4 increases, which increases operational costs, and there is also a risk that the fine dust DT staying there may flow into the gas collection section 5.

Therefore, in order to increase the recovery rate of the minute dust DT that continues to stay in the dust recovery section 4, as shown in FIGS. 1 and 3, the swirling space 4A of the dust recovery section 4 is connected to It has a constricted shape so that the flow path becomes smaller toward the inlet of the gas recovery section 5. The gas to be treated TG turns into an airflow flowing toward the gas recovery section 5 while being rotated by the gas recovery section 4 . Then, the minute dust DT contained in the gas to be processed TG does not continue to stay there, but moves along the horizontal flow while maintaining its momentum in the direction of travel, and is easily collected by the dust shooter 4B. Thereby, generation of minute dust DT that continues to stay in the dust collection section 4 can be suppressed, and the collection rate can be improved. In particular, the dust recovery section 4 only needs to have a constricted shape such that the flow path becomes smaller from the inlet of the gas to be treated toward the inlet of the gas recovery section 5; It is preferable that the tapered shape has a predetermined taper angle θ with respect to the traveling direction of the TG.

6 to 10 are graphs showing the ratio of staying dust and collected dust to the taper angle θ. In addition, FIG. 6 shows the turning amount η=60 [deg/m], FIG. 7 shows the turning amount η=75 [deg/m], FIG. 8 shows the turning amount η=90 [deg/m], and FIG. 9 shows the turning amount η. =120 [deg/m], and FIG. 10 shows the case where the turning amount η=150 [deg/m]. As shown in Figures 6 to 10, as the taper angle is gradually increased from 0°, the proportion of collected fine dust DT increases, but becomes almost constant when the angle exceeds a certain level. It has become a characteristic. Furthermore, the larger the amount of rotation η, the larger the taper angle θ at which the proportion of collected dust becomes constant.

FIG. 11 is a graph showing the ratio of the amount of dust DT collected when the taper angle θ=1 [deg] to the case where the taper angle θ=0 [deg]. As shown in FIG. 11, it can be seen that the collection rate is improved simply by making the turning space 4A of the dust collection section 4 into a tapered shape with a taper angle θ=1 [deg]. Further, as shown in FIG. 11, when the amount of rotation η is less than 75 [deg/m], the effect of collecting minute dust DT due to the tapered shape is weakened. Therefore, it is necessary that the turning amount η is 75 [deg/m] or more.

FIG. 12 shows the relationship between the amount of rotation η shown in FIGS. 6 to 10 and the maximum taper angle θmax at which the amount of collected dust DT becomes maximum at each amount of rotation η. As shown in FIG. 12, when the amount of rotation η=75 to 120 [deg/m], a proportional relationship is established between the amount of rotation η and the maximum taper angle θmax at which the recovery amount is maximum. It is preferable that the taper angle θ is set to the maximum taper angle θmax according to the turning amount η. However, when manufacturing the dust collection unit 4, the taper angle θ may deviate from the maximum taper angle θmax due to manufacturing errors or the like. Even in this case, a high recovery rate can be maintained while suppressing pressure loss as long as the amount of rotation is within the range η≧15×θ+45 (θ>0 [deg]). On the other hand, if the amount of swirling η becomes too large, the amount of dust DT that continues to swirl and stay without being collected increases. Therefore, in consideration of reducing the staying amount of dust DT, it is preferable to suppress the turning amount to a range of η≦15×θ+90 (θ>0 [deg]). For example, when the turning amount η=120 [deg/m], it is preferable that 2 [deg]≦the taper angle θ, and it is preferable that the taper angle θ≦5 [deg].

Further, when manufacturing the dust collection section 4, the taper angle θ may deviate from the maximum taper angle θmax due to manufacturing errors or the like. FIG. 13 shows the relationship between the amount of rotation η in FIGS. 6 to 10 and the maximum taper angle θmax at which the amount of recovery is maximum at each amount of rotation η. As shown in FIG. 13, when the amount of rotation η=75 to 150 [deg/m], as the amount of rotation η increases, the maximum taper angle θmax at which the recovery amount becomes maximum also tends to increase.

Even in this case, as long as the range satisfies the following formula (1), that is, the range shown by the solid line in FIG. 13, a high recovery rate of dust DT can be maintained while suppressing the pressure loss of the gas to be treated TG. can do. On the other hand, if the amount of swirling η becomes too large, the amount of dust DT that continues to swirl and stay without being collected increases. Therefore, in consideration of reducing the staying amount of dust DT, it is preferable to suppress the swirling amount η within the range of the following equation (1). For example, when the turning amount η=120 [deg/m], it is preferable that approximately 2 [deg]≦the taper angle θ, and it is also preferable that the taper angle θ≦10 [deg].

（θ＞０［ｄｅｇ］）

(θ>0[deg])

According to the embodiment described above, the dust collection section 4 has a constricted shape such that the flow path becomes smaller from the inlet side of the gas to be treated TG to the inlet side of the gas recovery section 5, and the amount of swirling is reduced. By setting η≧75 [deg/m], it is possible to reduce the amount of minute dust DT staying in the dust collection section 4 and improve the collection rate. At this time, the dust collection section 4 has a tapered shape with a taper angle θ [deg], and swirls the to-be-treated gas TG so that the swirling amount η≧15×θ+45 or the above formula (1) is satisfied. In this case, the recovery rate can be further improved.

The embodiments of the present invention are not limited to the above embodiments, and various changes can be made. In this embodiment, the case where the gas to be treated TG is exhaust gas from a blast furnace, converter, etc. is exemplified, but it can be used as long as the dust DT contained in the gas to be treated TG to be treated is separated. It doesn't matter what the purpose is. Further, although the dust separating section 3 in FIG. 2 is provided with a rectifying member 3B having a rectifying plate 3C at the center of the main body 3A, it is sufficient that the rectifying member 3B generates a swirling flow. For example, it may consist of a rectifying plate attached to the inner wall surface of the main body portion 3A.

In addition, although the case where the dust collection part 4 has a tapered shape is illustrated, it is sufficient that the dust collection part 4 has a constricted shape so that the flow path becomes small. For example, the bottom surface side is not sloped and the top surface side is The shape may be slanted or the like.

1 Cyclone dust collector 2 Inflow pipe 3 Dust separation section 3A Main body section 3B Straightening member 3C Straightening plate 4 Dust recovery section 4A Turning space section 4B Dust shooter 5 Gas recovery section DT Dust TG To be treated gas θ Taper angle η Turning amount

Claims (4)

A cyclone dust collector that collects dust from a gas to be treated,
a dust separation section that rotates the gas to be treated with a horizontal direction as a rotation axis and separates dust from the gas to be treated;
a dust recovery unit that is connected to an outlet side of the dust separation unit and collects the dust separated by swirling of the gas to be processed by the dust separation unit;
a gas recovery unit whose inlet side is installed within the dust recovery unit and recovers the to-be-treated gas from which the dust has been separated;
Equipped with
The dust recovery section is narrowed from the inlet side of the gas to be treated along the direction of the rotation axis so that the flow path becomes small , and has a taper with a taper angle θ [deg] (θ>0 [deg]). has a shape,
The dust separation section is a cyclone dust collector that swirls the to-be-treated gas so that the amount of swirl of the to-be-treated gas is 75 [deg/m] or more and 150 [deg/m] or less . The dust separation section includes a main body section having a gas flow path extending laterally;
A rectifying member installed in the gas flow path of the main body and having a rectifying plate formed in a spiral shape to cause the gas to be processed to flow laterally while swirling along the inner wall of the main body. ,
Equipped with
The amount of rotation is determined by the pitch or inclination angle of the current plate,
The cyclone dust collector according to claim 1. The cyclone collection according to claim 1 or 2, wherein the dust separation section swirls the to-be-treated gas so that η≧15×θ+45, where the amount of swirling of the to-be-treated gas is η [deg /m ]. dust equipment. The cyclone dust collector according to claim 1 or 2 , wherein the dust separation section swirls the to-be-treated gas so that the following formula is satisfied, where the amount of swirling of the to-be-treated gas is η [deg/m].

Images