JP2021179272A - Inner cylinder support structure of loop seal - Google Patents

Abstract

To provide an inner cylinder support structure of a loop seal which can suppress a temperature difference of a flange part at minimum.SOLUTION: An inner cylinder support structure of a loop seal includes a flange part 311 disposed to introduce particles into a casing 301 and formed in an upper end of an inner cylinder 310 a lower part of which is buried in the particles, and an inner step part 261 formed by expanding the inner diameter of a leg pipe 260 of a cyclone 200 so that the flange part 311 is exposed and mounted inside the leg pipe 260.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an inner cylinder support structure of a loop seal.

Generally, the loop seal is provided in a circulating fluidized bed boiler including a furnace for burning fuel and a cyclone for separating particles such as sand and ash in the combustion gas discharged from the furnace.

Then, in the loop seal, the casing is suspended from the leg pipe of the cyclone, and the return pipe extending from the casing is connected to the bottom of the furnace.

An inner cylinder for introducing particles is installed inside the casing of the loop seal, and by burying the lower part of the inner cylinder inside the particles, the pressure difference between the cyclone and the furnace is sealed, and the combustion gas in the furnace is sealed. The particles separated by the cyclone can be stably returned to the furnace while preventing the particles from flowing back to the cyclone side.

In the case of the conventional loop seal, an annular support metal fitting is projected on the inner surface side of the upper end portion of the casing, the flange portion of the inner cylinder is placed on the support metal fitting, and the upper and lower surfaces of the flange portion are covered with a refractory material. The structure is such that the inner cylinder is supported.

For example, Patent Document 1 shows the general technical level of the loop seal of the circulating fluidized bed boiler.

Japanese Patent No. 3897508

By the way, although high-temperature combustion gas is flowing inside the inner cylinder, heat is taken to the outside by the flange portion placed on the supporting metal fitting protruding from the casing. , The temperature is lower than the inside.

Therefore, the elongation of the flange portion becomes smaller than the extension of the inner cylinder in the radial direction where the temperature becomes relatively high, and as a result, the flange portion is deformed so as to shrink the inner cylinder. When such deformation occurs, even if the upper and lower surfaces of the flange portion are covered with a refractory material, a gap is generated in the outer peripheral end portion of the flange portion, and particles such as sand and ash enter the gap, and the above-mentioned The thermal elongation of the flange portion is hindered, and the deformation of the flange portion to shrink the inner cylinder is further promoted. When the deformation progressed to some extent, the load on the welded portion of the inner cylinder of the flange portion, which is structurally the weakest, increased, and improvement was desired.

Therefore, in this disclosure, in view of the above-mentioned conventional problems, an inner cylinder support structure of a loop seal that can minimize the temperature difference of the flange portion will be described.

The present disclosure comprises a casing in which particles separated by a cyclone and flowing down from the cyclone's leg canal are temporarily stored.
An inner cylinder that is arranged to introduce the particles inside the casing and whose lower portion is buried inside the particles.
In the inner cylinder support structure of the loop seal, which is connected to the upper side surface of the casing and has a return pipe for discharging particles.
The flange portion formed at the upper end of the inner cylinder and
It relates to an inner cylinder support structure of a loop seal provided with an inner step portion formed by expanding the inner diameter of the leg tube so that the flange portion is exposed and placed inside the leg tube of the cyclone. be.

The inner cylinder support structure of the loop seal may be provided with a hanging reinforcing material disposed on the outer step portion generated between the outer circumference of the leg tube and the outer circumference of the casing as the inner step portion is formed. preferable.

In the inner cylinder support structure of the loop seal, the flange portion is
The lower flange placed on the inner stage and
The upper flange, which is arranged upward from the lower flange at a required interval,
It is preferable to provide ribs radially arranged from the center of the flange portion so as to connect the lower flange and the upper flange.

Further, in the inner cylinder support structure of the loop seal, it is preferable that the lower flange is welded to the outer periphery of the inner cylinder and the upper flange is welded to the outer circumference of the inner cylinder.

Further, in the inner cylinder support structure of the loop seal, it is preferable to provide a taper formed on the upper surface of the outer peripheral end of the lower flange so as to have a downward gradient from the inner peripheral side to the outer peripheral side.

Furthermore, in the inner cylinder support structure of the loop seal, a holding beam projecting from the inner surface of the casing of the loop seal toward the inner cylinder side and arranged in a plurality of stages in the vertical direction,
It is preferable to provide a receiving member provided on the inner cylinder so as to sandwich the holding beam from both sides in the circumferential direction.

Further, in the inner cylinder support structure of the loop seal, it is preferable that a guide weir located above the flange portion and having an inner diameter smaller than the inner diameter of the inner cylinder is formed inside the leg tube of the cyclone.

Further, in the inner cylinder support structure of the loop seal, the loop seal is provided in a circulating fluidized bed boiler including a furnace for burning fuel and the cyclone for separating particles in combustion gas discharged from the furnace. And it is preferable that the return pipe is connected to the furnace.

According to the inner cylinder support structure of the loop seal of the present invention, it is possible to obtain an excellent effect that the temperature difference of the flange portion can be minimized.

It is the main part side sectional view explaining the form of the inner cylinder support structure of the loop seal by the Example of this disclosure, and is the magnified view of the part I of FIG. It is a top view which shows the lower flange of the inner cylinder support structure of the loop seal and the suspension reinforcement material according to the Example of this disclosure, and is the figure which corresponds to the arrow II-II of FIG. It is a main part side sectional view which shows the lower part vibration mechanism of the inner cylinder support structure of the loop seal by an Example of this disclosure, and is the enlarged view of the part III of FIG. It is a top view which shows the lower part vibration mechanism of the inner cylinder support structure of the loop seal by the Example of this disclosure, and is the figure corresponding to the arrow | view of IV-IV of FIG. It is a side sectional view which shows the upper shaking mechanism of the inner cylinder support structure of the loop seal according to the Example of this disclosure, and is the VV arrow view corresponding figure of FIG. It is an overall view which shows the circulation fluidized bed boiler to which the inner cylinder support structure of the loop seal by an Example of this disclosure is applied.

Hereinafter, embodiments of the present invention in the present disclosure will be described with reference to the accompanying drawings.

The inner cylinder support structure of the loop seal according to the embodiment of the present disclosure is applied to, for example, a circulating fluidized bed boiler. As shown in FIG. 6, the circulating fluidized bed boiler includes a furnace 100, a cyclone 200, a loop seal 300, and a rear heat transfer unit 400.

The furnace 100 burns fuel while being fluidized together with a bed material made of sand, limestone, or the like by the air blown from the air dispersion nozzle 110.

The cyclone 200 is connected to the upper part of the furnace 100 and collects particles such as sand and ash contained in the combustion gas generated by combustion in the furnace 100. Incidentally, the cyclone 200 includes a swivel introduction unit 210, a particle separation / recovery unit 220, an outlet duct 230, and an inner cylinder 240. The swirling introduction unit 210 is a portion where a gas containing particles is introduced so as to form a swirling flow. The particle separation / recovery unit 220 is a portion provided at the lower end of the swirl introduction unit 210 and whose diameter is reduced downward. The outlet duct 230 is connected to the upper end of the swivel introduction portion 210. The inner cylinder 240 is provided inside the swirl introduction portion 210 so as to guide the gas from which the particles are separated to the outlet duct 230. The cyclone 200 is supported by the support legs 250. Further, a leg tube 260 is connected to the lower end of the particle separation / recovery unit 220.

The loop seal 300 includes a casing 301, an inner cylinder 310, and a return pipe 330. The casing 301 is separated by the cyclone 200 so that particles flowing down from the leg tube 260 are temporarily stored. The inner cylinder 310 is arranged so as to introduce the particles into the casing 301, and the lower portion thereof is embedded in the particles. The return pipe 330 is connected to the upper side surface of the casing 301 and discharges particles to return the particles to the bottom of the furnace 100. An air dispersion nozzle 320 is provided at the bottom of the casing 301 to blow out air to fluidize the particles. Incidentally, the loop seal 300 prevents the combustion gas in the furnace 100 from flowing back to the cyclone 200 side even if the pressure in the lower part of the furnace 100 is higher than the pressure in the lower part of the cyclone 200, and the cyclone. Particles such as sand and ash separated in 200 can be stably returned to the furnace 100.

In the rear heat transfer unit 400, a combustion gas in which particles such as sand and ash are collected by the cyclone 200 is introduced, and a heat transfer tube group 410 constituting a superheater, a reheater, an economizer, etc. is introduced therein. It is arranged so that the heat of the combustion gas can be recovered and used for power generation.

Then, in the case of the present embodiment, as shown in FIGS. 1 and 2, a flange portion 311 is formed at the upper end of the inner cylinder 310, and the flange portion 311 is exposed inside the leg tube 260 of the cyclone 200. It is characterized in that the inner diameter of the leg tube 260 is expanded to form the inner step portion 261 so that it can be placed. The inner diameter of the leg tube 260 is extended over the entire length in the vertical direction of the leg tube 260.

The inner step portion 261 is formed by displacing the inner peripheral surface position of the refractory material 262 that covers the inner surface of the leg tube 260 toward the outer peripheral side from the inner peripheral surface position of the refractory material 302 that covers the inner surface of the casing 301 of the loop seal 300. The upper surface of the inner cylinder support member 303 disposed on the inner peripheral surface of the upper end portion of the casing 301 of the loop seal 300 is exposed. The inner cylinder support member 303 is composed of a support bracket 304 projecting to the inner surface side of the casing 301 of the loop seal 300, and an annular plate 305 mounted on the support bracket 304.

The refractory material 262 and the refractory material 302 are intentionally shown by virtual lines in FIGS. 1, 3, and 5. This is for clearly showing the inner cylinder support member 303 and clearly showing the reinforcing bracket 263 disposed on the inner surface of the lower end portion of the leg tube 260.

With the formation of the inner step portion 261, an outer step portion 264 is formed between the outer circumference of the leg tube 260 and the outer circumference of the casing 301 of the loop seal 300. Therefore, a hanging reinforcing material 265 is attached to the outer step portion 264 so that the hanging reinforcing material 265 supports the weight of the loop seal 300. The suspension reinforcing material 265 has a base material 266 welded to the outer periphery of the leg pipe 260 so as to extend in the vertical direction, and an upper portion welded to the base material 266 to be hung down and a lower end portion to the casing 301 of the loop seal 300. It is provided with a holding material 267 to be welded. As shown in FIG. 2, the base material 266 is made of T-shaped steel, and the holding material 267 is made of H-shaped steel. However, it goes without saying that the base material 266 and the holding material 267 may each be composed of angle steel, channel steel, or a member formed by bending a metal plate material.

Further, the flange portion 311 may be composed of one flange, but in the case of this embodiment, the flange portion 311 includes a lower flange 312, an upper flange 313, and a rib 314. The lower flange 312 is welded to the outer periphery of the inner cylinder 310 and placed on the inner step portion 261. More specifically, as shown in FIG. 1, the lower flange 312 is placed on the upper surface of the annular plate 305. The upper flange 313 is welded to the outer periphery of the inner cylinder 310 at a required interval upward from the lower flange 312. The ribs 314 are welded so as to connect the lower flange 312 and the upper flange 313, and are arranged radially from the inner peripheral side to the outer peripheral side of the flange portion 311 as shown in FIG.

Furthermore, a taper 315 is formed on the upper surface of the outer peripheral end of the lower flange 312 so as to have a downward gradient from the inner peripheral side to the outer peripheral side.

Further, as shown in FIGS. 3 and 4, the lower portion of the inner cylinder 310 is configured to suppress movement in the turning direction (circumferential direction) and the radial direction by the lower vibration damping mechanism 340. The lower vibration damping mechanism 340 includes a holding beam 341 and a receiving member 342. The holding beams 341 project from the inner surface of the casing 301 of the loop seal 300 toward the inner cylinder 310, and are arranged at a plurality of locations (for example, four locations) in the circumferential direction and a plurality of stages (for example, two stages) in the vertical direction. There is. The receiving member 342 is provided so as to sandwich the tubular body 344 attached to the lower outer periphery of the inner cylinder 310 via the fixture 343 and the tip end portion of the holding beam 341 from both sides in the circumferential direction on the outer peripheral surface of the tubular body 344. It is equipped with a holding piece 345.

As shown in FIGS. 2 and 5, the upper portion of the inner cylinder 310 is configured to be restrained from moving in the turning direction (circumferential direction) and in the radial direction by the upper shaking mechanism 350. The upper anti-vibration mechanism 350 includes a protrusion 351 and a concave groove 352. The protrusion 351 is fixed so that the upper portion protrudes from the upper surface of the annular plate 305 and the lower portion is embedded in the annular plate 305 and the refractory material 262. The concave groove 352 is formed in the lower flange 312 so as to engage with the protrusion 351.

As shown in FIGS. 1 and 5, a guide weir 268 is formed inside the leg tube 260 of the cyclone 200. The guide weir 268 is formed of a refractory material 262 so as to be located above the flange portion 311 and the inner diameter d is smaller than the inner diameter D of the inner cylinder 310. The guide dam 268 has a flow-down conical surface 268a whose inner diameter is gradually reduced from above to downward to become d, a cylindrical surface 268b that hangs down from the lower end of the flow-down conical surface 268a and has a uniform inner diameter at d, and the cylindrical surface. It is provided with a divergent conical surface 268c whose inner diameter is gradually expanded downward from the lower end of 268b.

Next, the operation of the above embodiment will be described.

By expanding the inner diameter of the leg tube 260 to form the inner step portion 261, the flange portion 311 formed at the upper end of the inner cylinder 310 is exposed and placed inside the leg tube 260.

The flange portion 311 is exposed to a high-temperature combustion gas like the inner cylinder 310, and the temperature does not drop without being deprived of heat to the outside.

Therefore, a relative temperature difference does not occur between the flange portion 311 and the inner cylinder 310, and the elongation of the flange portion 311 is not smaller than the radial elongation of the inner cylinder 310, resulting in the said. It is possible to prevent the flange portion 311 from being deformed so as to shrink the inner cylinder 310.

When the temperature difference between the flange portion 311 and the inner cylinder 310 disappears and deformation does not occur, the load on the welded portion of the structurally weakest flange portion 311 with respect to the inner cylinder 310 is greatly reduced.

On the other hand, as the inner step portion 261 is formed, an outer step portion 264 is formed between the outer circumference of the leg tube 260 and the outer circumference of the casing 301 of the loop seal 300. The outer step portion 264 is a so-called discontinuous portion in which the casing 301 of the loop seal 300 is simply bent from the leg tube 260 without hanging. However, a base material 266 constituting the suspension reinforcing material 265 is welded to the outer periphery of the leg pipe 260, and an upper portion of the holding material 267 is welded to the base material 266 and hung down. The lower end is welded to the casing 301 of the loop seal 300. Therefore, the weight of the loop seal 300 is stably supported by the suspension reinforcing material 265, and the casing 301 of the loop seal 300 is not deformed.

Further, the lower flange 312 constituting the flange portion 311 is welded to the outer periphery of the inner cylinder 310 and placed on the inner step portion 261. As shown in FIG. 1, the annular plate 305 has an annular plate 305. It is placed on the upper surface. The upper flange 313 constituting the flange portion 311 is welded to the outer periphery of the inner cylinder 310 at a required interval upward from the lower flange 312. The ribs 314 constituting the flange portion 311 are welded so as to connect the lower flange 312 and the upper flange 313, and are arranged radially from the inner peripheral side to the outer peripheral side of the flange portion 311 as shown in FIG. There is. As a result, the strength of the entire inner cylinder 310 including the flange portion 311 is improved, and it is possible to form a structure resistant to deformation. Here, if the welded portion of the lower flange 312 or the upper flange 313 is present on the inner peripheral portion of the inner cylinder 310, the maximum bending stress is concentrated on the welded portion when the inner cylinder 310 is thermally expanded and deformed. It works like a target. However, since the welded portions of the lower flange 312 and the upper flange 313 exist on the outer periphery of the inner cylinder 310, even if the inner cylinder 310 is thermally expanded and deformed, the maximum bending stress is concentrated on the welded portion. Can be avoided.

Furthermore, by exposing the flange portion 311, there is a high possibility that particles such as sand and ash will be deposited on the tip of the lower flange 312 of the flange portion 311 and the thermal elongation of the flange portion 311 will be hindered. However, even if particles such as sand and ash are deposited on the tip of the lower flange 312 of the flange portion 311, the upper surface of the outer peripheral end of the lower flange 312 has a downward gradient from the inner peripheral side to the outer peripheral side. A taper 315 is formed. Therefore, the taper 315 acts like a wedge and easily enters the particles, so that the thermal elongation of the flange portion 311 is not hindered.

Moreover, as shown in FIGS. 1 and 5, a guide weir 268 having a flowing conical surface 268a, a cylindrical surface 268b, and a divergent conical surface 268c is formed inside the leg tube 260 of the cyclone 200. Therefore, the particles are stably guided from the flowing conical surface 268a of the guide weir 268 to the inside of the inner cylinder 310 via the cylindrical surface 268b, become difficult to reach the divergent conical surface 268c side, and directly reach the flange portion 311. Avoid hitting.

Further, the particles temporarily stored in the loop seal 300 are fluidized by the air blown from the air dispersion nozzle 320, and the lower part of the inner cylinder 310 is buried inside the particles. Therefore, the inner cylinder 310 The vibration becomes large. However, as shown in FIGS. 3 and 4, the lower portion of the inner cylinder 310 has a holding piece 345 projecting from the cylinder 344 of the receiving member 342 of the lower vibration damping mechanism 340 from the inner surface of the casing 301 to the inner cylinder 310 side. By engaging with the tip of the holding beam 341 overhanging, the movement in the turning direction and the radial direction is suppressed, and the support is stably supported. Moreover, since the holding beams 341 of the lower vibration damping mechanism 340 are arranged in a plurality of stages (for example, two stages) in the vertical direction, it is effective in further suppressing the vibration of the inner cylinder 310.

As shown in FIGS. 2 and 5, the upper portion of the inner cylinder 310 is swiveled in the turning direction by the concave groove 352 of the upper anti-vibration mechanism 350 engaging with the projecting piece 351 protruding from the upper surface of the annular plate 305. In addition, radial movement is suppressed and stable support is provided.

In this way, the temperature difference of the flange portion 311 can be minimized.

Then, in the case of the present embodiment, the suspension reinforcement provided on the outer step portion 264 generated between the outer circumference of the leg pipe 260 and the outer circumference of the casing 301 of the loop seal 300 as the inner step portion 261 is formed. The material 265 is provided. With this configuration, even if there is an outer step portion 264 between the leg tube 260 and the loop seal 300, which is a so-called discontinuous portion that bends without simply hanging, the suspension reinforcing material The weight of the loop seal 300 is stably supported by 265.

Further, the flange portion 311 includes a lower flange 312 mounted on the inner step portion 261, an upper flange 313 arranged upward from the lower flange 312 at a required interval, and the lower flange 312 and the upper side. It is provided with ribs 314 radially arranged from the inner peripheral side to the outer peripheral side of the flange portion 311 so as to connect with the flange 313. With such a configuration, it is effective to improve the strength of the entire inner cylinder 310 including the flange portion 311 and to make the structure resistant to deformation.

Further, the lower flange 312 is welded to the outer circumference of the inner cylinder 310, and the upper flange 243 is welded to the outer circumference of the inner cylinder 310. If a welded portion of the lower flange 312 or the upper flange 243 is present on the inner peripheral portion of the inner cylinder 310, the maximum bending stress acts intensively on the welded portion when the inner cylinder 310 is thermally expanded and deformed. However, if the welded portion of the lower flange 312 and the upper flange 243 exists on the outer periphery of the inner cylinder 310, even if the inner cylinder 310 is thermally expanded and deformed, the maximum bending stress is concentrated on the welded portion. It is advantageous because it does not act on.

Further, the lower flange 312 is provided with a taper 315 formed on the upper surface of the outer peripheral end so as to have a downward gradient from the inner peripheral side to the outer peripheral side. With this configuration, when the particles are deposited on the tip of the lower flange 312 of the flange portion 311, the taper 315 can act like a wedge to facilitate entry into the particles, and the flange portion 311 can be easily inserted. It is effective for smooth heat expansion.

Further, the holding beam 341 projecting from the inner surface of the casing 301 of the loop seal 300 toward the inner cylinder 310 side and being arranged in a plurality of stages in the vertical direction, and the holding beam 341 are sandwiched between the inner cylinder 310 so as to be sandwiched from both sides in the circumferential direction. It is provided with a receiving member 342 provided. With this configuration, the inner cylinder 310, whose lower portion is buried inside the particles and whose vibration tends to increase, can be stably supported.

Further, inside the leg pipe 260 of the cyclone 200, a guide weir 268 located above the flange portion 311 and having an inner diameter d smaller than the inner diameter D of the inner cylinder 310 is formed. With this configuration, the particles can be stably guided to the inside of the inner cylinder 310, and contact of the particles with the flange portion 311 can be avoided.

Further, the loop seal 300 is provided in a circulating fluidized bed boiler including a furnace 100 for burning fuel and the cyclone 200 for separating particles in combustion gas discharged from the furnace 100, and the return pipe 330. Is connected to the furnace 100. With such a configuration, in particular, the loop seal 300 provided in the circulating fluidized bed boiler can be stably operated.

The inner cylinder support structure of the loop seal of the present invention is not limited to the above-described embodiment described in the present disclosure, and various modifications can be made without departing from the gist of the present invention. Of course.

100 Fire furnace 110 Air dispersion nozzle 200 Cyclone 210 Swivel introduction part 220 Particle separation and recovery part 230 Outlet duct 240 Inner cylinder 250 Support leg 260 Leg tube 261 Inner step part 262 Fireproof material 263 Reinforcing bracket 264 Outer step part 265 Suspended reinforcement 266 base Material 267 Retaining material 268 Guide dam 268a Flowing conical surface 268b Cylindrical surface 268c Wide conical surface 300 Loop seal 301 Casing 302 Fireproof material 303 Inner cylinder support member 304 Support bracket 305 Circular plate 310 Inner cylinder 311 Flange part 312 Lower flange 313 Upper flange 314 Rib 315 Tapered 320 Air distribution nozzle 330 Return pipe 340 Lower vibration mechanism 341 Holding beam 342 Receiving member 343 Fixture 344 Cylinder 345 Holding piece 350 Upper vibration mechanism 351 Projection piece 352 Concave groove 400 Rear heat transfer part 410 Heat transfer tube group D inner diameter d inner diameter

Claims (8)

A casing that is separated by a cyclone and temporarily stores particles that flow down from the cyclone's leg tube.
An inner cylinder that is arranged to introduce the particles inside the casing and whose lower portion is buried inside the particles.
In the inner cylinder support structure of the loop seal, which is connected to the upper side surface of the casing and has a return pipe for discharging particles.
The flange portion formed at the upper end of the inner cylinder and
An inner cylinder support structure of a loop seal including an inner step portion formed by expanding the inner diameter of the leg tube so that the flange portion is exposed and placed inside the leg tube of the cyclone. The inner cylinder support structure of the loop seal according to claim 1, further comprising a hanging reinforcing material disposed on the outer step portion generated between the outer circumference of the leg tube and the outer circumference of the casing as the inner step portion is formed. .. The flange portion is
The lower flange placed on the inner stage and
The upper flange, which is arranged upward from the lower flange at a required interval,
The inner cylinder support structure for a loop seal according to claim 1 or 2, further comprising ribs radially arranged from the center of the flange portion so as to connect the lower flange and the upper flange. The inner cylinder support structure of the loop seal according to claim 3, wherein the lower flange is welded to the outer periphery of the inner cylinder, and the upper flange is welded to the outer circumference of the inner cylinder. The inner cylinder support structure of the loop seal according to claim 3 or 4, wherein the upper surface of the outer peripheral end of the lower flange is provided with a taper formed so as to have a downward gradient from the inner peripheral side to the outer peripheral side. A holding beam that projects from the inner surface of the casing of the loop seal toward the inner cylinder side and is arranged in multiple stages in the vertical direction.
The inner cylinder support structure of a loop seal according to any one of claims 1 to 5, further comprising a receiving member provided on the inner cylinder so as to sandwich the holding beam from both sides in the circumferential direction. The loop seal according to any one of claims 1 to 6, wherein a guide weir located above the flange portion and having an inner diameter smaller than the inner diameter of the inner cylinder is formed inside the leg tube of the cyclone. Cylinder support structure. The loop seal is provided in a circulating fluidized bed boiler equipped with a furnace for burning fuel and the cyclone for separating particles in combustion gas discharged from the furnace, and the return pipe is connected to the furnace. The inner cylinder support structure of the loop seal according to any one of claims 1 to 7.

Images