JP2018096639A - Fluidized bed system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an accumulation amount of solid matter, accumulated below a partition plate, per unit time.SOLUTION: A fluidized bed system 100 includes: a fluidized bed chamber 220 having an input port 222a provided on a first side wall 222, and a discharge port 224a provided on a second side wall 224 facing the first side wall 222; and a partition plate 270 provided between the first side wall 222 and the second side wall 224 in the fluidized bed chamber 220 so that a distance to the second side wall 224 is 0.8-3 times a distance B determined based on slagging, and configured to partition the inside of the fluidized bed chamber 220 into an upstream chamber 272 and a downstream chamber 274 so as to maintain a state of communicating with a bottom surface.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a fluidized bed system including a fluidized bed chamber in which a solid fluidized bed is formed.

  A fluidized bed system using a fluidized bed formed by jetting gas from the bottom to the top of a fluidized bed chamber in which particulate solids are accommodated is used to dry, burn, gasify, and granulate solids. It is used in various fields.

  In the fluidized bed system, a technique for equalizing the residence time of solids by providing a partition plate extending in the vertical direction in the fluidized bed chamber has been developed (for example, Patent Document 1).

JP-A-10-160348

  However, the solid matter handled in the fluidized bed system may vary in size (particle size). In this case, relatively large solid matter stays (deposits) below the partition plate, and the lower portion of the partition plate is blocked by the solid matter, so that the operation cannot be performed. For this reason, there is a problem that the maintenance frequency increases.

  In view of such a problem, the present disclosure is intended to provide a fluidized bed system capable of reducing the retention amount per unit time of solid matter deposited below the partition plate.

In order to solve the above-described problem, a fluidized bed system according to an aspect of the present disclosure includes a fluidized bed having an input port provided in a first side wall and a discharge port provided in a second side wall facing the first side wall. The distance between the first side wall and the second side wall in the fluidized bed chamber is 0.8 to 3 times the distance B represented by the following formula (A). And a partition plate that divides the fluidized bed chamber into an upstream chamber and a downstream chamber while maintaining communication with the bottom surface.

  Moreover, you may provide the extraction opening provided in the bottom face of the said fluidized bed chamber from the perpendicular downward direction of the said partition plate to the perpendicular downward direction of the said 2nd side wall.

  It becomes possible to reduce the residence amount per unit time of the solid substance deposited below the partition plate.

It is a figure explaining a fluid bed system. It is a figure explaining the distance of a partition plate and a 2nd side wall. It is a figure explaining the result of having simulated the movement of the particle by the difference in the distance in a downstream chamber. It is a figure explaining the simulation result of the mass flow rate from an upstream chamber to a downstream chamber by the difference in distance.

  Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiment are merely examples for facilitating understanding, and do not limit the present disclosure unless otherwise specified. In the present specification and drawings, elements having substantially the same functions and configurations are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present disclosure are not illustrated. To do.

(Fluidized bed system 100)
FIG. 1 is a diagram illustrating a fluidized bed system 100. In the present embodiment, a configuration in which the fluidized bed system 100 dries lignite as a fluidized medium will be described as an example. In FIG. 1, the gas flow is indicated by solid arrows, and the flow of the fluid medium is indicated by broken arrows. As shown in FIG. 1, the fluidized bed system 100 includes an introduction unit 110 and a fluidized bed unit 210.

(Introduction unit 110)
The introduction unit 110 includes a conveyor 112, a hopper 114, an introduction pipe 116, and an introduction valve 118. The conveyor 112 conveys lignite to the hopper 114 from a lignite supply source. The hopper 114 temporarily stores the lignite transported by the conveyor 112. The introduction pipe 116 is a pipe that communicates the hopper 114 and the fluidized bed portion 210 (the inlet 222a of the fluidized bed chamber 220). The introduction valve 118 is provided in the introduction pipe 116 and adjusts the opening degree of the introduction pipe 116.

(Fluidized bed part 210)
The fluidized bed unit 210 includes a fluidized bed chamber 220, a fluidized gas supply unit 230, a heat transfer unit 240, an overflow unit 250, a cyclone 260, and a partition plate 270.

  The fluidized bed chamber 220 is a rectangular parallelepiped container. An input port 222 a is provided in the first side wall 222 constituting the fluidized bed chamber 220. In addition, a discharge port 224 a is provided in the second side wall 224 facing the first side wall 222 among the side walls constituting the fluidized bed chamber 220. An inlet pipe 116 is connected to the inlet 222a, and lignite is introduced into the fluidized bed chamber 220 through the inlet 222a. And the fluidized bed chamber 220 accommodates the introduced lignite.

  The fluidizing gas supply unit 230 supplies fluidizing gas (for example, water vapor) from the bottom surface of the fluidized bed chamber 220. More specifically, the fluidizing gas supply unit 230 includes an air box 232, a fluid pipe 234, and a blower 236.

  The air box 232 is provided below the fluidized bed chamber 220. The upper portion of the air box 232 also functions as a bottom surface of the first side wall 222 and is formed of a dispersion plate 232a that can be ventilated. The dispersion plate 232a is constituted by, for example, a plate provided with a plurality of apertures having a diameter smaller than the particle size of lignite, or a plate provided with a nozzle. The flow pipe 234 is connected to the wind box 232. Further, the flow pipe 234 is provided with a blower 236 for feeding a fluidizing gas. The blower 236 supplies the fluidizing gas to the fluid pipe 234 at a flow rate at which a fluidized bed of lignite is suitably formed in the fluidized bed chamber 220.

  Thus, the fluidizing gas is supplied into the fluidized bed chamber 220 by the blower 236. The fluidizing gas causes the lignite to flow in the fluidized bed chamber 220 to form a fluidized bed of lignite. The blower 236 evaporates a part of the water contained in the lignite by bringing the fluidizing gas into contact with the lignite.

  The heat transfer unit 240 is constituted by, for example, a pipe through which a heat medium flows, and is arranged in the fluidized bed chamber 220 (in this embodiment, an upstream chamber 272 described later). The heat transfer unit 240 heats the lignite with the heat of the heat medium in the flow process of the heat medium. With the configuration including the heat transfer section 240, heat exchange is performed between the heat medium and the fluidizing gas in the fluidized bed chamber 220, and the fluidizing gas moving upward can be further heated. Therefore, drying of lignite with fluidized gas is further promoted.

  The overflow unit 250 includes an overflow pipe 252 connected to the discharge port 224a. The overflow part 250 sends the lignite overflowed from the discharge port 224a to the outside. More specifically, when lignite is introduced into the fluidized bed 210 (in the fluidized bed chamber 220) through the inlet 222a, the volume of the fluidized bed increases by the volume of the introduced lignite. Then, lignite (fluidized bed) overflows from the discharge port 224 a and is sent to the outside through the overflow pipe 252.

  The cyclone 260 is connected to a vent 226 a formed in the ceiling 226 of the fluidized bed chamber 220. The cyclone 260 solid-separates the fluidized gas discharged from the fluidized bed chamber 220 through the vent 226a. The fluidized gas that has passed through the fluidized bed chamber 220 contains lignite. Therefore, by providing the cyclone 260, the fluidized gas (including lignite) discharged from the fluidized bed chamber 220 through the vent 226a is solid-gas separated. Then, the fluidized gas separated by the cyclone 260 is exhausted to the outside. Moreover, the lignite separated by the cyclone 260 is sent to the outside.

  Thus, undried lignite is introduced into the fluidized bed chamber 220, the lignite is heated by the fluidizing gas supply unit 230 and the heat transfer unit 240, and a part of the water is evaporated and removed from the lignite. On the other hand, the flow of the lignite will be described. The lignite introduced into the fluidized bed chamber 220 through the inlet 222a becomes a fluidized bed in the fluidized bed chamber 220, moves in the fluidized bed chamber 220, and discharges 224a, overflow. The fluid is discharged from the fluidized bed chamber 220 to the outside through the pipe 252.

  By the way, lignite has variations in size (particle size). For this reason, when the flow rate of the fluidizing gas supplied by the blower 236 is set so that relatively small particles (hereinafter referred to as “small particles”) can form a fluidized bed, relatively large particles (hereinafter “ The large particles ”are not fluidized and are deposited in the lower part of the fluidized bed chamber 220. On the other hand, when the flow velocity is set so that large particles can form a fluidized bed, small particles are scattered and discharged to the outside through the vent 226a. Therefore, the blower 236 supplies the fluidizing gas at a flow rate at which particles having an average particle diameter can form a fluidized bed. However, the moving speed in the fluidized bed chamber 220 varies depending on the size of the particles, and the residence time of the particles in the fluidized bed chamber 220 varies. For this reason, the lignite discharged | emitted may be produced, without drying.

  Therefore, in the fluidized bed unit 210 of the present embodiment, a partition plate 270 is provided in the fluidized bed chamber 220. The partition plate 270 is provided between the first side wall 222 and the second side wall 224 in the fluidized bed chamber 220 so as to be separated from the ceiling 226 and the bottom surface (dispersion plate 232a) of the fluidized bed chamber 220. The partition plate 270 is provided substantially in parallel with the first side wall 222 and the second side wall 224. The partition plate 270 is connected to both side walls of the fluidized bed chamber 220 other than the first sidewall 222 and the second sidewall 224, and the fluidized bed chamber 220 is partitioned into an upstream chamber 272 and a downstream chamber 274. To do. The upstream chamber 272 is formed between the first side wall 222 and the partition plate 270, and the downstream chamber 274 is formed between the partition plate 270 and the second side wall 224. Therefore, the fluidized bed (brown coal) formed in the upstream chamber 272 moves to the downstream chamber 274 through the lower side of the partition plate 270. In the present embodiment, the partition plate 270 is provided in the fluidized bed chamber 220 so that the downstream chamber 274 has a smaller horizontal cross-sectional area (volume) than the upstream chamber 272.

  With the configuration including the partition plate 270, the particles pass below the partition plate 270 regardless of the size. As a result, it is possible to avoid a situation where the particles move from the inlet port 222a to the outlet port 224a at the shortest distance. Therefore, the variation in residence time can be reduced (the residence time can be equalized (averaged)).

  On the other hand, when the partition plate 270 is provided, lignite may be clogged below the partition plate 270 (between the lower end of the partition plate 270 and the dispersion plate 232a). More specifically, large particles that are not fluidized stay in the lower part of the fluidized bed chamber 220. As a result, large particles accumulate, and the lower part of the partition plate 270 is blocked by the large particles.

  Therefore, an outlet 280 is provided on the bottom surface (dispersion plate 232a) of the fluidized bed chamber 220, and large particles are extracted from the fluidized bed chamber 220 through the outlet 280. An extraction pipe 282 is connected to the extraction outlet 280, and an opening / closing valve 284 is provided in the extraction pipe 282.

  However, the particles extracted from the outlet 280 are insufficiently dried. More specifically, the heat transfer unit 240 is provided above the dispersion plate 232a by a predetermined distance in consideration of function securing and maintenance of the dispersion plate 232a. For this reason, the particles deposited in the lower part of the fluidized bed chamber 220 are insufficiently dried. Therefore, the particles extracted from the outlet 280 are insufficiently dried. For this reason, a technique for reducing the amount of particles extracted from the outlet 280 is desired.

  Therefore, the distance between the partition plate 270 and the second side wall 224 is devised to reduce the retention amount per unit time of the particles staying at the bottom of the fluidized bed chamber 220.

ここで、平均層高Ｈは、脈動する流動層の高さ（層高）の時間的な平均値である。 FIG. 2 is a diagram for explaining the distance between the partition plate 270 and the second side wall 224. For ease of understanding, the inlet 222a, outlet 224a, vent 226a, and outlet 280 are omitted in FIG. As shown in FIG. 2, in the present embodiment, the distance R between the partition plate 270 and the second side wall 224 is in the range of 0.8 to 3 times the distance B represented by the following formula (A). In addition, a partition plate 270 is provided in the fluidized bed chamber 220.

Here, the average bed height H is a temporal average value of the height of the fluidized bed (bed height).

By increasing the flow velocity of the particles in the downstream chamber 274, the particles staying in the lower part of the fluidized bed chamber 220 are lifted up to the discharge port 224a. More specifically, the flow rate of particles in the downstream chamber 274 is calculated using the following formula (B).
Particle flow rate = (input amount−extraction amount−overflow amount) / (R × L) Formula (B)
Therefore, the smaller the distance R is, the more the flow rate of particles in the downstream chamber 274 can be improved.

  However, if the distance R is less than 1.0 times the distance B (hereinafter referred to as “1.0B”), slagging (bumping) occurs in the downstream chamber 274. When slagging occurs, the fluidized bed chamber 220 and the equipment on the downstream side (downstream of the fluidized bed chamber 220) are impacted. On the other hand, when the distance R exceeds 3.0 times the distance B (hereinafter referred to as “3.0B”), the bubbles do not become large and the large particles cannot be lifted, and the large particles are in the bottom surface of the downstream chamber 274. Stays on.

  FIG. 3 is a diagram for explaining the result of simulating the movement of particles due to the difference in the distance R in the downstream chamber 274. 3A shows the simulation result when the distance R is 1.0B, and FIG. 3B shows the simulation result when the distance R is 3.0B. In FIG. 3, only large particles having a particle size of 500 μm or more are shown.

  As shown in FIG. 3A, when the distance R = 1.0B, the large particles in the downstream chamber 274 can reach (lift) the discharge port 224a. On the other hand, as shown in FIG. 3B, when the distance R = 3.0B, the flow rate in the downstream chamber 274 is low and large particles cannot reach the discharge port 224a.

  Further, as the distance R in the downstream chamber 274 is reduced, the amount of large particles that move from the upstream chamber 272 to the downstream chamber 274 increases. FIG. 4 is a diagram for explaining a simulation result of the mass flow rate from the upstream chamber 272 to the downstream chamber 274 due to the difference in the distance R. 4A shows the mass flow rate of particles having a particle size of 20 μm to 3000 μm, and FIG. 4B is an enlarged view of the mass flow rate of FIG. 4A having a particle size of 500 μm to 1100 μm. FIG. 4 (c) shows an enlarged view of the mass flow rate with the particle size in FIG. 4 (a) ranging from 1100 μm to 3000 μm. In FIG. 4, the distance R = 1.0B is indicated by a solid line, and the distance R = 3.0B is indicated by a broken line.

  As shown in FIG. 4, it can be seen that large particles having an average particle diameter of 500 μm or more move from the upstream chamber 272 to the downstream chamber 274 at a distance R = 1.0B. On the other hand, it was found that the large particles having an average particle size of 500 μm or more hardly move to the downstream chamber 274 at the distance R = 3.0B.

  As described above, by setting the distance R within the range of 1.0B or more and 3.0B or less, the particles staying at the bottom of the fluidized bed chamber 220 can be efficiently moved to the discharge port 224a. As described above, the shorter the distance R, the higher the flow rate of the downstream chamber 274. Therefore, the distance R is preferably 1.0B. However, even if the distance R is 0.8B, the durability of the fluidized bed chamber 220 can be maintained. For this reason, the distance R may be within a range of 0.8B to 3.0B.

Further, as shown in the following formulas (C) to (E), when the average bed height H of the downstream chamber 274 and the flow rate Qb of fluidized gas per unit area supplied to the downstream chamber 274 are equal, the distance The smaller the R, the larger the bubble diameter Db.

  As described above, the downstream chamber 274 has a smaller horizontal cross-sectional area than the upstream chamber 272. That is, the distance R is smaller in the downstream chamber 274 than in the upstream chamber 272. Therefore, as shown in the above formulas (C) to (E), the size of the fluidized gas bubbles in the downstream chamber 274 is larger than that of the upstream chamber 272. That is, the fluidized bed formed in the downstream chamber 274 has a lower density than the fluidized bed in the upstream chamber 272. Therefore, the movement of particles (brown coal) from the upstream chamber 272 to the downstream chamber 274 can be promoted by the chimney effect.

  Moreover, in the fluidized bed part 210 of this embodiment, lignite moves smoothly from the upstream chamber 272 to the downstream chamber 274, and most large particles can be discharged | emitted from the discharge port 224a. Therefore, when the outlet 280 is provided in the bottom surface of the fluidized bed chamber 220 (dispersion plate 232a), between the vertical lower side of the partition plate 270 and the vertical lower side of the second side wall 224, preferably just below the partition plate 270. Good. As a result, it is possible to avoid a situation where the particles are blocked below the partition plate 270.

  As described above, according to the fluidized bed system 100 according to the present embodiment, the partition plate 270 is provided in the fluidized bed chamber 220, and the distance R between the partition plate 270 and the second side wall 224 is within the above range. Thus, large particles can be led to the discharge port 224a. As a result, the amount of solid matter deposited per unit time below the partition plate 270 can be reduced. Therefore, the amount of particles extracted from the outlet 280 can be reduced.

  As mentioned above, although embodiment was described referring an accompanying drawing, it cannot be overemphasized that this indication is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims and that they naturally fall within the technical scope.

  For example, in the above embodiment, lignite has been described as an example of the fluid medium. However, there is no limitation on the type of fluid medium as long as it is a particulate solid.

  Moreover, in the said embodiment, the structure which the fluidized bed part 210 dries lignite was mentioned as an example, and was demonstrated. However, if the fluidized bed system 100 can form a fluidized bed of solids and perform processing (drying, combustion, gasification, granulation, etc.) on the solids, the fluidized bed unit 210 can perform processing. There is no limitation.

  Moreover, in the said embodiment, the partition plate 270 demonstrated and demonstrated as an example the structure provided spaced apart from the ceiling 226 and bottom face (distribution plate 232a) of the fluidized bed chamber 220. FIG. However, the shape of the partition plate 270 is not limited as long as the partition plate 270 can be partitioned from the upstream chamber 272 and the downstream chamber 274 while maintaining a communication state with the bottom surface. For example, the partition plate may be a plate extending from the ceiling 226 to the bottom surface and having holes in the upper and lower portions, or a plate having holes in only the lower portion. Further, a part of the partition plate may be connected to the ceiling 226 or the bottom surface.

  Moreover, in the said embodiment, the structure which the fluidized bed part 210 was provided with the outlet 280 was mentioned as an example, and was demonstrated. However, when the distance R from the partition plate 270 to the second side wall 224 is set to a distance R that allows all particles to be discharged from the discharge port 224a, the outlet port 280 can be omitted.

  The present disclosure can be used for a fluidized bed system including a fluidized bed chamber in which a fluidized bed of solids is formed.

100 Fluidized bed system 220 Fluidized bed chamber 222 First side wall 222a Input port 224 Second side wall 224a Outlet port 226 Ceiling 232a Dispersion plate (bottom surface)
270 Partition plate 272 Upstream chamber 274 Downstream chamber 280 Exit

Claims (2)

A fluidized bed chamber having an input port provided in the first side wall and a discharge port provided in the second side wall facing the first side wall;
Between the first side wall and the second side wall in the fluidized bed chamber, the distance to the second side wall is within a range of 0.8 to 3 times the distance B represented by the following formula (A). A partition plate that divides the fluidized bed chamber into an upstream chamber and a downstream chamber while maintaining a communication state with the bottom surface,
Fluidized bed system.

  2. The fluidized bed system according to claim 1, further comprising an outlet provided between a bottom surface of the fluidized bed chamber and a position vertically below the partition plate and vertically below the second side wall.

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