JP2511378Y2 - Fluidized bed boiler - Google Patents

Description

[Detailed description of the device]

[0001]

[Field of Industrial Application] The present invention supplies coal to a fluidized combustion chamber where sand flows to burn it, heats water in a heat transfer tube to generate steam, and burns gas after burning with a desulfurizing agent. The present invention relates to a fluidized bed boiler that desulfurizes and discharges to the outside.

[0002]

2. Description of the Related Art In recent years, a fluidized bed boiler has been developed as a boiler having high combustion efficiency and little pollution of waste gas. This type of fluidized bed boiler is equipped with three chambers, a storage chamber, a combustion chamber, and a desulfurization chamber, which are sequentially separated from the lower stage in the boiler main body. The sand stored in the chamber is made to flow by blowing air, and the coal supplied to the combustion chamber is burned while flowing along with the sand.The heat transfer tube in the combustion chamber makes contact with this combustion gas and heated fluid medium. Steam is generated by heating the water which is heated by the heat transfer tube and passes through the heat transfer tube. Then, the combustion gas is desulfurized with a desulfurizing agent such as limestone in the desulfurization chamber and exhausted, and unburned carbon is captured and burned in the desulfurization chamber.

[0003]

A fluidized bed boiler of this type is provided with a plurality of cylindrical dispersion pipes, and the fluidizing air blown up from below is dispersed and flows in each direction. Layer and desulfurization layer are evenly supplied. However, in the conventional dispersion pipe, sand as a fluid medium or limestone as a desulfurizing agent flows back into the lower chamber through the dispersion pipe due to the pressure fluctuation of blown air, etc., and especially the fuel supply is dispersed. When air transportation is performed just above the pipe, the fluid medium flows backward due to the blowing of air and the combustion of volatile components, and it easily falls from the holes of the dispersion pipe, which deteriorates the fluid state and makes the desulfurization state unstable. In addition to the above, the fluid medium and the desulfurizing agent which have fallen back due to flow and the desulfurizing agent have to be collected and replenished, so that there is a problem that the burden of labor increases and the equipment cost for the collecting device increases.

[0004]

In order to solve such problems, according to the present invention, a plurality of partition plates are provided between the upper and lower chambers, and air is supplied from the lower chamber through the lower portion of the main pipe 30c. A dispersion pipe 30 for air dispersion that is introduced and blows out the air from the upper part to the upper chamber, and the outer diameter of the upper end of the main pipe 30c of the dispersion pipe 30 is made larger than the outer diameter of the main pipe 30c by a predetermined amount.
And it was closed by a disc 30a, the inside of the upper part facing the upper chamber of the main pipe 30c mains 30c disc 3 at the upper closed portion of
An annular space portion 30g is formed between the inner tube 30b and the main pipe 30c and the upper end is opened to the lower surface and spacing 0a provided inner tube 30b which is opened upwardly, the lower end portion of the annular space 30g The diameter D of the peripheral wall of the lower end portion 30d of the inner pipe is gradually increased from the upper side to the lower side.
The towards main pipe 30c side by joining the main pipe 30c by forming a <br/> Kana curve slide with a predetermined radius of curvature R, occluded, at a position lower than the upper end opening 30e of the inner tube And a plurality of air outlets communicating with the annular space 30g in the circumferential direction of the main pipe 30c at the same height position as the upper surface S of the inner pipe 30b at the joining point of the lower end of the inner pipe to the main pipe. The hole 30f is provided.

[0005]

The air introduced into the main pipe from the lower end of the main pipe of the dispersion pipe ascends in the main pipe and passes through the inner pipe located in the upper portion of the main pipe facing the upper chamber of the main pipe and above it. Is discharged from the open end of the main pipe, collides with the upper end closed part of the main pipe, is inverted, and flows down into the annular space between the inner pipe and the main pipe and into the upper chamber from the plurality of air blowing holes of the main pipe. It is jetted and dispersed. Even if the fluidized medium in the upper chamber may enter the annular space inside the main pipe from the air blow-out hole of the main pipe, it will enter the inner pipe from the opening at the upper end of the inner pipe higher than the air blow-out hole. It never invades and flows backwards.

However, since the air blowing holes of the main pipe are formed as a plurality of holes scattered around, the inflow of the fluidized medium is prevented as much as possible. Then, when the fluid medium flows in, it accumulates at the lower end portion of the annular space, and when it advances and becomes higher than the air blowing hole, it overflows the air blowing hole and tries to flow out of the main pipe. At this time, this accumulated portion is a smooth curve with a predetermined radius of curvature R toward the main pipe so that the diameter D of the peripheral wall of the lower end portion of the inner pipe gradually increases from the upper side to the lower side. Is formed and joined to the main pipe, and the air blowing hole is located at the same height position as the upper surface of the inner pipe at this joining point. The slip resistance of the inner wall of the lower end of the inner pipe having the smooth curve is reduced, and the lower end of the inner pipe is moved by the air flow that descends the annular space and flows toward the air blowing hole. Since it is slid down and pushed along the peripheral wall of the smooth curved line, and tries to flow out from the air blowing hole to the upper chamber outside, the outflow to the outside of the main pipe is extremely smooth. Therefore,
Even if the fluidized medium flows into the main pipe during the boiler operation , the backflow into the inner pipe is reliably prevented. In addition, the main of the dispersion pipe
The outer diameter at the upper end was made larger than the outer diameter of the main pipe by a predetermined amount.
Since the disk is attached, the boiler is
The fluid medium was not flowing at the time of rotation stop, and the dispersion pipe was the fluid medium.
Bottom edge of the disc even when covered with
Below the outer peripheral edge of the
Since the space portion is formed, the flowing medium is the air blowing hole.
It is made difficult to enter as much as possible. Further, the diameter of the peripheral wall of the lower end portion of the inner pipe is gradually increased from the upper side to the lower side as described above, and a smooth curve is formed toward the main pipe side so that the inner wall is connected to the main pipe. Air smoothly flows into the pipe.

[0007]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. 1 and 2 show an embodiment of a fluidized bed boiler according to the present invention, FIG. 1 is a longitudinal sectional view of a dispersion pipe, and FIG. 2 is a longitudinal sectional view of a fluidized bed boiler. In the figure, the main body 1 of the fluidized bed boiler is formed in a rectangular box shape surrounded by water cooling walls 2 in which a plurality of water cooling pipes (not shown) are embedded, and has a rectangular box shape. Partition plates containing 3 4, 5, 6
The air chamber 7, the storage chamber 8, the combustion chamber 9,
The desulfurization chamber 10 is separated. An air transportation type coal supply pipe 13 connected to a coal supply hopper (not shown) via a dryer and a crusher is engaged with the air chamber 7 and the storage chamber 8 to supply coal. ing.

Further, in the desulfurization chamber 10, an air transportation type limestone transport pipe 14 connected to a limestone supply hopper (not shown) is engaged, and a predetermined amount of limestone 15 is constantly stored in the desulfurization chamber 10. It is supplied to be. Reference numeral 16 denotes a heat transfer tube which is curved and installed so as to reciprocate in the combustion chamber 9 in a zigzag manner. A water supply pipe 17 connected to one end of the heat transfer pipe is connected to a circulation pump and also connected to the other end. The supply pipe 18 is connected to a steam using facility. In the present embodiment, a bypass connecting the water supply pipe 17 and the supply pipe 18 is provided to serve as a heat transfer tube of a separately provided exhaust heat utilization boiler. 30 is each partition plate 4,
A plurality of distributors 5 and 6 are provided as the dispersing pipes which blow up the air into the upper chamber while uniformly distributing the blown air, and the structure thereof will be described with reference to FIG.

The distributor 30 is formed in a tubular shape in which the upper end of the main pipe 30c is closed by a disc 30a.
In the upper part of the inside facing the upper chamber of the main pipe 30c, the main pipe 30
An inner pipe 30b having an opening 30e with an upper end facing upward is attached to the lower face of the disc 30a at the upper end of c, and an annular space 30g is provided between the main pipe 30c and the inner pipe 30b. Are formed. The outer diameter of the disk 30a is the main building
It is formed with a predetermined amount larger than the outer diameter of 30c.
And, in the lower end portion of the annular space 30g, the peripheral wall of the lower end portion 30d of the inner pipe 30b extends from the upper side to the lower side and has a diameter of the peripheral wall.
A smooth curve is formed with a predetermined radius of curvature R toward the main pipe 30c so that D gradually increases, and the inner wall surface of the main pipe 30c is joined and closed. And
The main pipe 30c is located at a position lower than the upper end opening 30e of the inner pipe 30b and at the lower end 30d of the inner pipe 30b.
At the same height as the upper surface S of the inner pipe 30b at the joining point to the air outlet hole 3 communicating with the annular space 30g.
0f is provided in the lateral direction. This air blowing hole 3
A plurality of 0f are provided in the circumferential direction of the main pipe 30c.

Further, sand 20 as a fluid medium having a diameter of about 1.6 mm is stored in the storage chamber 8, and the same sand 20 is stored in the combustion chamber 9 as well. Reference numerals 21 and 22 denote upper and downcomers for the sand 20, which are provided to connect the storage chamber 8 and the combustion chamber 9, respectively, and the sand 20 is placed between the chambers 8 and 9 manually or by a level detection by a sensor. It is configured to reciprocate so that the amount of sand 20 in the combustion chamber 9 is always kept constant. On the other hand, a discharge port 23 for discharging combustion gas is provided at the upper end of the desulfurization chamber 10, and is connected to a chimney via the exhaust heat utilization boiler by a duct. 24 is the desulfurization chamber 1
It is an outlet that is opened at 0 to overflow the limestone 15 and extract it to the outside.

The operation of the fluidized bed boiler configured as described above will be described. Combustion chamber 9 before operation starts or when operation stops
The fluid medium sand 20 or the limestone 15 in the desulfurization chamber 10 flows
When it is not liquidized or when fluidization is stopped
Sand 20 or limestone 15 accumulates on the cut plate 5 or the partition plate 6.
Distributor 30 is sand 20 or limestone 1
When it is covered with 5, the distribution
Of the disk 30a by the action of the disk 30a at the upper end of the rotor 30.
Rest of sand 20 and limestone 15 below the outer edge of the bottom edge
The corners form an inverted cone-shaped space, and the sand 20 or
Inflow of limestone 15 into the air outlet 30f is blocked as much as possible
Is set to be Then, coal is supplied from the coal supply pipe 13 to the layer of sand 20 stored in the combustion chamber 9 , air is sent to the air chamber 7 and the storage chamber 8, and then the preheated coal is ignited by a burner or the like, The coal is burned by the supply of the combustion air, and this combustion is promoted by the blowing air from the distributor 30 which causes the sand 20 and the coal to flow, and the coal is efficiently burned. This combustion heats the water in the heat transfer tube 16 to generate steam, which is supplied to the steam using facility. On the other hand, the combustion gas enters the desulfurization chamber 10 via the distributor 30 above the combustion chamber 9 and is discharged from the discharge port 23 as a harmless gas with the sulfur content removed, and unburned carbon is captured in the desulfurization chamber 10. Is burned. The combustion gas discharged from the discharge port 23 raises the temperature of steam flowing from the supply pipe 18 to the steam using facility when passing through a separately provided boiler, and then is discharged from the chimney.
After the desulfurization reaction, the limestone 15 in the desulfurization chamber 10 overflows from the outlet 24 and is discharged to a limestone storage tank or the like.

In such a fluidized bed boiler, since the distributor 30 is constructed as described above, the air blown into the main pipe 30c of the distributor 30 from the lower chamber rises in the main pipe 30c. And flows into the inner pipe 30b located in the upper portion of the main pipe 30c facing the upper chamber. At this time, the lower end portion 30d of the inner pipe 30b is gradually increased in diameter from the upper side to the lower side as described above and is formed in a smooth curve toward the main pipe 30c side. The air has a low flow resistance and flows in smoothly. Then, the air is discharged from the opening 30e at the upper end of the inner pipe 30b, collides with the lower surface of the disc 30a at the upper end of the main pipe 30c, and is reversed, and the inner pipe 30b and the main pipe 30 are
Inflow into the annular space 30g between the main pipe 30c and the main pipe 30c
The air is blown out into the upper chamber from the plurality of air blowing holes 30f without any trouble and dispersed. Therefore, sand 20 and limestone 15
A stable fluidized state can be achieved, and uniform combustion and desulfurization are performed.

Even if the sand 20 or limestone 15 which is the fluid medium in the upper chamber enters the annular space 30g inside the main pipe 30c from the air blowing hole 30f in the main pipe 30c, the air blowing hole 30f can be used. The inner pipe 30b does not enter and flow backward through the opening 30e at the upper end of the inner pipe at a higher position. In addition, since the air blowing holes 30f of the main pipe 30c are formed as a plurality of holes scattered around, the inflow of, for example, sand 20 as a fluid medium is prevented as much as possible. When the sand 20 flows in, the annular space 30g
When it accumulates on the lower end portion 30d of the air blower and its height becomes higher than that of the air blowing hole 30f, the air blowing hole 3
0f overflows and tries to flow out of the main pipe 30c.

At this time, the deposited portion is the inner pipe 30.
The diameter D of the peripheral wall of the inner pipe 30b at the lower end 30d of b is
It is gradually increased from the upper side to the lower side, and a smooth curve having a radius of curvature R is formed toward the main pipe 30c side and is joined to the main pipe 30c. At this joining point, it is equivalent to the upper surface S of the inner pipe 30b. Since the air blowing hole 30f is located at the height position of the inner pipe 30b in which this smooth curve is formed, the sand 20 that has accumulated and becomes heavier in weight is located.
Since the peripheral wall of the lower end portion 30d has a small slip resistance, and also due to the air flow that descends the annular space 30g and flows toward the air blowing hole 30f, the lower wall is formed along the wall formed by this smooth curve. Since it will be slid and pushed away to the outside and will try to flow out from the air blowing hole 30f to the upper chamber outside as it is, the outflow to the outside of the main pipe 30c is carried out very smoothly. Therefore, even if the sand 20 flows into the main pipe 30c, the backflow to the inner pipe 30b can be reliably prevented. This is the dispersion pipe 3 provided in the desulfurization chamber 10.
The same is true for limestone 15 at 0 .

[0015]

As is apparent from the above description, according to the present invention, in a fluidized bed boiler, the air blown into the dispersion pipe from below is expanded to the inner pipe from its top to bottom. It smoothly flows in from the lower end, passes through the upper end opening of the inner pipe, passes through the annular space, and is blown up into the upper chamber from the multiple air blowing holes around the main pipe. , Even if the fluid medium in the upper chamber and the desulfurizing agent may enter the annular space inside the main pipe from the air blowing hole of the main pipe, the opening at the upper end of the inner pipe is at a position higher than the air blowing hole. It is possible to prevent the intrusion into the inner pipe and the backflow.

[0016] In the present invention, in particular, the outer diameter of the main pipe
A disc formed by making it larger than the outer diameter by a specified amount.
An inverted conical space corresponding to the angle of repose of the fluidized medium particles is formed below
Fluid medium before operation starts or when operation is stopped
When the body is at rest, the flowing medium flows into the air outlets of the mains.
Are as difficult, also, since the air blowing holes of the main pipe is formed as a plurality interspersed pores in the circumferential direction, luck
Before the start of rotation, during operation stop or during operation
It is possible to prevent the flowing medium from flowing into the discharge hole as much as possible, and even when the flowing medium flows into the annular space portion, the portion below the annular space portion where the flowing medium flows in and accumulates.
As for the structure of the peripheral wall of the inner pipe at the end portion, the diameter D of the peripheral wall of the inner pipe is
The main pipe 30 gradually increases from the bottom to the bottom.
Blow air from the inner pipe to the main pipe with a radius of curvature R toward the c side
It has a structure in which it is connected by a smooth curve toward the outlet hole , and the flowing medium that has flowed into the peripheral wall of the inner pipe at the lower end of the annular space part descends in the annular space part and blows out air. With the help of the air flow flowing toward the holes, it is naturally pushed down by its own weight and discharged to the outside, so that the flowing medium can be made to flow out of the main pipe very smoothly. . Therefore, the dispersion pipe of the present invention is designed to blow air of fluid medium particles.
It is possible to prevent entry into the hole as much as possible.
Even fluidized medium flows into the tube of the fluidized medium in the main tube
Accumulation can be effectively prevented and backflow into the inner tube can be prevented more reliably. For this reason, it is not necessary to collect and replenish the fluidized medium that has flowed back to the lower chamber, which saves labor and saves equipment costs because there is no need to install a recovery device. The boiler operation rate will be improved for those that are recovered.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a dispersion tube of the present invention.

FIG. 2 is a vertical sectional view showing an embodiment of the fluidized bed boiler of the present invention.

[Explanation of symbols]

 1 Fluidized bed boiler main body 4, 5, 6 Partition plate 7 Air chamber 8 Storage chamber 9 Combustion chamber 10 Desulfurization chamber 15 Limestone 20 Sand 30 Distributor (dispersion pipe) 30a Disk 30b Inner pipe 30c Main pipe 30d Inner pipe lower end 30e Inside Tube opening 30f Air blowing hole 30g Annular space R Inner tube lower end curvature radius S Upper surface

Claims (1)

(57) [Scope of utility model registration request] 1. A plurality of partition plates are provided between the upper and lower chambers,
Air dispersion dispersion pipe 3 for introducing air from the lower chamber through the lower part of the main pipe 30c and blowing the air from the upper part to the upper chamber
0 , the outer diameter of the upper end of the main pipe 30c of the dispersion pipe 30
A disk 3 in which the outer diameter of the main pipe 30c is increased by a predetermined amount.
Closed by 0a, it was towards the upper end opening of the lower surface <br/> and spacing of the disc 30a of the upper closed portion of inside the main pipe 30c of the upper part facing the upper chamber of the main pipe 30c upwardly is opened Inner tube 30
b is provided to form an annular space between the inner pipe 30b and the main pipe 30c.
Forming a 30g, the lower end portion of the annular space portion 30g, over the peripheral wall of the lower end portion 30d of the inner tube from the top downward peripheral wall
As the diameter D becomes gradually larger main pipe 30 a peripheral wall
toward the c side by joining the main pipe 30c to form a smooth curve with a predetermined radius of curvature R, occluded, at a position lower than the upper end opening 30e of the inner tube and the inner tube lower end Inner pipe 30 at the junction of the part to the main
A fluidized bed boiler having a plurality of air blowing holes 30f communicating with the annular space 30g in the circumferential direction of the main pipe 30c at the same height position as the upper surface S of b .