JP2005030626A - Fluidized bed boiler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove residues of a disposal target object or/and fuel in combustion disposal without stopping operation of a fluidized bed boiler. <P>SOLUTION: In the fluidized bed boiler with a fluidized bed formed by supplying combustion gas from a lower part of a furnace 1 filled with bed material X, and carrying out combustion disposal by supplying fuel or/and the disposal target object Y to the fluidized bed, a residue removal mechanism 2 is provided for collecting and removing the residue of the disposal target object Y in combustion disposal along with the bed material X as bed ash X1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluidized bed boiler.
[0002]
[Prior art and problems to be solved by the invention]
As an incinerator that treats sludge and waste liquid, and a boiler for power generation that uses sludge, biomass, etc. as fuel, the bed is filled with inert minerals such as river sand and the combustion bed is blown from the hearth to create a fluidized bed. There is a fluidized bed boiler that is formed, keeps this sand (bed material) at 600 to 900 ° C., and puts an object to be treated or / and fuel into this layer and burns it. This fluidized bed boiler is a type that can burn the object to be treated and / or fuel most efficiently as an incinerator and a power generation boiler, and is widely used.
[0003]
In recent years, this fluidized bed boiler has been used not only for sludge and waste liquid, but also for combustion of waste-derived fuel such as waste tires and RDF (garbage solidified fuel). However, for example, waste tires include not only a rubber component that can be burned by a combustion process but also a metal wire made of steel that cannot be burned. For this reason, when the waste tire is combusted with a fluidized bed boiler, the rubber component is vaporized and ashed, and discharged to the outside, but the metal wire is deposited as a residue in the lower part of the furnace. When this residue (metal wire) accumulates, it becomes difficult to form a good fluidized bed. Therefore, it is necessary to stop the operation of the fluidized bed boiler at regular intervals and remove the residue, for example, manually by an operator. is there.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-314506
The present invention has been made in view of the above-described problems, and an object of the present invention is to remove a processing object and / or fuel residue in a combustion process without stopping operation of a fluidized bed boiler.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, as a first means, a fluidized bed is formed by supplying a combustion gas from below the furnace filled with the bed material, and fuel or / and processing is performed in this fluidized bed. A fluidized bed boiler that supplies and burns an object and employs a configuration that includes a residue removal mechanism that collects and removes the residue of the object to be treated in the combustion process as bed ash together with the bed material.
[0007]
As a second means, in the first means, the residue removal mechanism includes a floor portion of the furnace having a plurality of gaps, and a separation mechanism that separates and removes the residue from the bed ash that has passed through the floor portion. The configuration is provided with.
[0008]
As a third means, a configuration is adopted in which the second means is provided with a circulation mechanism for supplying the bed ash, which has become a bed material by removing the residue by the sorting mechanism, into the furnace again.
[0009]
As a fourth means, in the second or third means, the residue removing mechanism includes a hopper mechanism that collects the bed ash that has passed through the floor and supplies the bed ash to the sorting mechanism. .
[0010]
As a fifth means, in any one of the first to fourth means, a configuration is adopted in which the residue removing mechanism includes a cooling mechanism for cooling the bed ash.
[0011]
As a sixth means, in the fifth means, the cooling mechanism includes a first cooler for cooling the bed ash immediately after passing through the floor portion, and the bed ash just before being supplied to the sorting mechanism. A configuration is adopted in which a second cooler for further cooling is provided.
[0012]
As a seventh means, in any one of the fourth to sixth means, the residue removing mechanism includes a core that is disposed inside the hopper mechanism and allows the bed ash to pass evenly over the entire surface of the floor portion. The configuration is adopted.
[0013]
As an eighth means, in any one of the second to seventh means, the floor portion adopts a configuration of a plurality of air diffuser tubes or air diffuser nozzles for supplying the combustion gas to the furnace.
[0014]
As a ninth means, in any one of the second to eighth means, the residue is a metal material, and the separation mechanism is a magnetic separator that separates and removes the metal material from the bed ash by magnetic force. To do.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a fluidized bed boiler according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram illustrating the overall configuration of a fluidized bed boiler according to the present embodiment. In this figure, reference numeral 1 is a furnace, 2 is a metal removal mechanism (residue removal mechanism), 3 is a cyclone, 4 is a heat exchanger, 5 is a heat transfer section, and X is a bed material.
[0016]
The furnace 1 is gasified and incinerated by burning the waste tire Y supplied as fuel in the inside of the furnace 1 and has a rectangular parallelepiped or cylindrical shape that is long in the height direction. The furnace 1 is filled with a bed material X made of an inert inorganic material such as river sand.
[0017]
A metal removal mechanism 2 is disposed at the lower part of the furnace 1. FIG. 2 is a diagram showing an overall configuration of the metal removal mechanism 2 and is a schematic configuration diagram including a partial cross-sectional view. As shown in this figure, the metal removal mechanism 2 includes a plurality of diffuser tubes 21 that form the floor portion of the furnace 1, hoppers 22 and 23 (hopper mechanisms) formed with predetermined inclined surfaces, and directly below the diffuser tube 21. The first cooler 24 disposed in the hopper, the core 25 disposed inside the hoppers 22 and 23, the second cooler 26 disposed below the hoppers 22 and 23, and a magnetic separator 27 for removing metal objects by magnetic force. It has.
[0018]
A plurality of the diffuser tubes 21 are arranged in the lower part of the furnace 1 to form the floor part of the furnace 1, and as shown in the view of the floor part of the furnace 1 shown in FIG. It arrange | positions so that the clearance gap d may be formed between each diffuser tube 21. FIG. The air diffuser 21 is a tubular member in which a plurality of nozzles or a plurality of holes are formed, and is connected to the combustion air supply device 6 (combustion gas supply device) shown in FIG. ing.
[0019]
The hoppers 22 and 23 are disposed below the diffuser tube 21 so as to cover the floor surface of the furnace 1, and discharge ports 22 a and 23 a are formed at the lower end portions of the hoppers 22 and 23. Specifically, the floor surface of the furnace 1 is covered by connecting the hoppers 22 and 23 having semicircular upper opening ends. By arranging two hoppers in this way, the height of the fluidized bed boiler can be lowered. A plurality of hoppers may be installed instead of the two hoppers. Of course, if the height of the fluidized bed boiler is not limited, a single hopper may be installed.
[0020]
Returning to FIG. 2, for example, an air-cooled first cooler 24 connected to the combustion air supply device 6 is disposed above the hoppers 22, 23, that is, directly below the diffuser pipe 21. In the hoppers 22 and 23 (below the first cooler 24 and above the discharge ports 22a and 23a), a substantially conical shape fixed and supported on the inner wall surfaces of the hoppers 22 and 23 by a support member (not shown). The core 25 is disposed so as to be located above the discharge ports 22a and 23a. By disposing the core 25 inside the hoppers 22 and 23 in this way, the volume of the hoppers 22 and 23 can be reduced, and the filling amount when the bed material X is initially filled can be reduced.
[0021]
Below the discharge ports 22a and 23a formed in the hoppers 22 and 23, for example, an air-cooled second cooler 26 is disposed. The first cooler 24 and the second cooler 26 constitute a cooling mechanism according to the present invention.
The magnetic separator 27 separates and collects metal objects from the discharge (bed ash described later) cooled by the second cooler 26 by magnetic force. An example of such a magnetic separator 27 is a belt conveyor type in which permanent magnets are arranged on a belt.
[0022]
Returning to FIG. 1, the cyclone 3 is for collecting the ash and bed material X contained in the exhaust gas generated as a result of the combustion treatment in the furnace 1, and is connected to the upper part of the furnace 1. Yes.
[0023]
The heat exchanger 4 is connected to the lower part of the cyclone 3 and fluidizes the ash and the bed material X collected by the cyclone 3. The heat exchanger 4 is connected to the lower part of the furnace 1 by an ash return pipe 7. An air dispersion pipe 41 is disposed below the heat exchanger 4, and fluidized air is supplied from the combustion air supply device 6 into the heat exchanger 4 through the air dispersion pipe 41. It is configured as follows.
[0024]
The heat transfer section 5 forms a flow path for supplying to the exhaust gas line 8 of exhaust gas exhausted from the upper part of the cyclone 3, for example, for driving a power generation steam turbine (not shown). The superheater and the economizer used are arranged. Note that an air preheater, a dust collector, and the like (not shown) are disposed in the middle of the exhaust gas line 8. In addition to the superheater and the economizer, a heat transfer tube disposed in the heat exchanger 4 is also used for the power generation steam turbine.
[0025]
In addition, the fluidized bed boiler according to the present embodiment includes a circulation mechanism 9 that again supplies the exhaust from which the metal is removed in the metal removal mechanism 2 to the inside of the furnace 1. The circulation mechanism 9 is composed of, for example, a fan or the like, and supplies the exhaust discharged from the magnetic separator 27 of the metal removal mechanism 2 to the furnace 1 by pneumatic feeding. The circulation mechanism 9 is not limited to the one that discharges the air pressure, and a belt conveyor or the like may be used.
[0026]
Further, a second combustion air supply device 10 for supplying secondary combustion air for assisting combustion of unburned fuel generated in the combustion process in the furnace 1 to the furnace 1 in the middle of the furnace 1. Is connected.
A fuel inlet (not shown) for supplying fuel to the furnace 1 is formed in the middle of the furnace 1, and the furnace 1 is ignited inside the furnace 1 when the fluidized bed boiler is started. A starting burner (not shown) that performs the above is disposed.
[0027]
Next, the operation of the fluidized bed boiler according to the present invention configured as described above will be described. In the present embodiment, the fluidized bed boiler performs a combustion process of waste tires.
[0028]
First, when the combustion air supply device 6 is driven, combustion air (combustion gas) is supplied to the furnace 1 from a nozzle or a hole formed in the air diffusion pipe 21 of the metal removal mechanism 2. At the same time, fluidized air is supplied to the inside of the heat exchanger 4 via the air dispersion pipe 41 and combustion air is also ejected from the first cooler 24. Due to the combustion air supplied to the furnace 1, a part of the bed material X filled in the furnace 1 becomes a fluidized state, and a fluidized bed is formed. Further, auxiliary second combustion air is supplied to the furnace 1 from the second combustion air supply device 10.
[0029]
Then, the waste tire Y or the like, which is sheared to a suitable size by a cutting device or the like on the outside, is supplied into the fluidized bed, that is, the furnace 1 through a fuel inlet.
The combustion air, the second combustion air, and the waste tire Y are always supplied to the furnace 1 continuously when the fluidized bed boiler is in operation.
[0030]
When the waste tire Y is supplied into the furnace 1, ignition is performed by the start burner at the time of initial startup, and the waste tire Y is combusted in the furnace 1. In the combustion treatment process inside the furnace 1, the metal wire contained in the waste tire Y falls on the bed material X accumulated in the lower part of the furnace 1 without being gasified and ashed by the combustion treatment. That is, in the lower part of the furnace 1, the bed material X containing metal that is a residue of the waste tire Y in the combustion process is deposited. In the following description, the bed material X containing metal (residue) is referred to as bed ash X1.
[0031]
The bed ash X1 passes through a gap d formed between the diffuser tubes 21 and is dropped and recovered below the diffuser tube 21 while being cooled by being blown with combustion air by the first cooler 24. . At this time, since the core 25 is disposed in the hoppers 22 and 23, the amount of the bed ash X1 that passes through the gap d located above the center of each hopper 22 and 23 is suppressed. Usually, the gap d located above the central part of the hoppers 22 and 23 has the largest passing amount of the bed ash X1, and the passing amount of the bed ash X1 decreases as the distance from the central part increases. For this reason, by arranging the conical core 25 as described above, the bed ash X1 deposited in the lower part of the furnace 1 is uniformly spaced between the diffuser tubes 21 over the entire floor of the furnace 1. Falls downward from
As a result, the bed ash X1 deposited in the lower part of the furnace 1 becomes uniform with respect to the floor surface, so that a good fluidized bed can be maintained.
[0032]
The bed ash X1 dropped downward from the gap d between the diffuser tubes 21 is collected by dropping along the inclined surfaces of the hoppers 22 and 23, and is discharged to the outside of the hoppers 22 and 23 through the discharge ports 22a and 23a. Discharged as waste.
[0033]
The bed ash X1 discharged as effluent from the hoppers 22 and 23 is further cooled by the second cooler 26 and then supplied to the magnetic separator 27. Here, the two coolers for cooling the bed ash X1 are provided because the bed ash X1 is in a high temperature state of about 870 ° C. in the furnace 1. This is because it is difficult to cool the bed ash X1 to the durable temperature of the magnetic separator 27.
[0034]
The bed ash X1 supplied to the magnetic separator 27 becomes a bed material X by separating and removing metal contained therein by the magnetic force, and is supplied again into the furnace 1 by the circulation mechanism 10. Further, the metal object separated and removed by the magnetic separator 27 is continuously discharged to the outside.
[0035]
Then, the gasified and ashed waste tire Y generated by the combustion process inside the furnace 1 is supplied to the cyclone 3 from the upper part of the furnace 1 as an exhaust gas Y1 containing the ashed product and the bed material X.
Here, the exhaust gas Y <b> 1 is supplied to the heat transfer unit 5 from the upper part of the cyclone 3 after the ash and the bed material X are removed by the cyclone 3. And after exhaust gas Y1 is supplied to the exhaust gas line 8 via the superheater, the economizer, etc. which are arrange | positioned in the heat-transfer part 5, it is exhausted outside via an air preheater, a dust collector, etc.
[0036]
Further, the ashed product and the bed material X collected by the cyclone 3 are cooled by heat exchange in the heat exchanger 4, and then supplied to the furnace 1 again through the ash return pipe 7.
[0037]
Thus, according to the fluidized bed boiler concerning this embodiment, it becomes possible to remove a metal thing continuously, without stopping operation of a fluidized bed boiler.
[0038]
As mentioned above, although preferred embodiment of the fluidized-bed boiler which concerns on this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.
[0039]
For example, in the above embodiment, the fluidized bed boiler is a so-called circulating fluidized bed boiler in which the ash collected by the cyclone 3 is supplied again into the furnace 1. However, the present invention is not limited to this, and the fluidized bed boiler according to the present invention may be a so-called bubbling fluidized bed boiler that forms a fluidized bed by generating bubbles in particles such as lime. . In this case, the air diffuser shown in the above embodiment is arranged instead of the so-called flat window box.
[0040]
Moreover, in the said embodiment, the combustion process of the waste tire Y was performed. However, the fluidized bed boiler according to the present invention is not limited to this, and for example, combustion of fuel containing incombustibles may be performed. In addition, you may supply the fuel etc. containing this incombustible material to the furnace 1 with the waste tire Y. FIG.
[0041]
Moreover, in the said embodiment, since the waste tire Y was processed, the metal wire which consists of steel which is a ferromagnetic material became a residue. For this reason, although separation removal was possible by using the magnetic separator 27 as a separation mechanism, when using fuel derived from wastes, such as RDF, for example, a paramagnetic metal and non-metal are used. The case where it becomes a residue can be assumed. In such a case, the residue can be separated and removed by using, for example, a vibration buoy or the like that separates substances by vibration as a separation mechanism.
[0042]
Moreover, in the said embodiment, since the waste tire Y was continuously supplied in the furnace 1, the operation of the metal removal mechanism 2 also became continuous. However, when the waste tire Y is supplied into the furnace 1 in a batch, the operation of the metal removal mechanism 2 can also be a batch.
[0043]
Moreover, in the said embodiment, the combustion air was supplied into the furnace 1 inside from the floor part by comprising the floor part which concerns on this invention with the some diffuser tube 21. FIG. However, it is not always necessary to supply combustion air from the floor. Specifically, a configuration having a floor portion in which a plurality of gaps are formed and a combustion air supply pipe connected to the lower portion of the furnace 1 may be adopted.
[0044]
【The invention's effect】
As described above, according to the present invention, a fluidized bed is formed by supplying combustion gas from below the furnace filled with the bed material, and fuel or / and an object to be treated are supplied to the fluidized bed. A fluidized bed boiler for combustion treatment, comprising a residue removal mechanism for collecting and removing the residue of the object to be treated in the combustion treatment as bed ash together with the bed material, so that combustion without stopping the operation of the fluidized bed boiler It is possible to remove a processing object and / or a fuel residue in the processing.
[Brief description of the drawings]
FIG. 1 is a schematic view showing the overall configuration of a fluidized bed boiler according to an embodiment of the present invention.
FIG. 2 is a diagram showing an overall configuration of a metal removal mechanism 2 according to an embodiment of the present invention.
FIG. 3 is a view of the floor portion of the furnace 1 according to an embodiment of the present invention as viewed from above.
[Explanation of symbols]
1 ... Furnace 2 ... Metal removal mechanism (residue removal mechanism)
21 …… Air diffuser (floor)
22, 23 ... Hopper (hopper mechanism)
24 …… First cooler 25 …… Core 26 …… Second cooler 27 …… Magnetic separator (separation mechanism)
3 ... Cyclone 4 ... Heat exchanger 5 ... Transmission unit 6 ... Combustion gas supply device 7 ... Ash return pipe 8 ... Exhaust gas line 9 ... Circulation mechanism X ... Bed material X1 ... Bed ash Y ... ... Waste tires (objects to be treated)
Y1 …… Exhaust gas

Claims (9)

A fluidized bed boiler that forms a fluidized bed by supplying a combustion gas from below a furnace filled with a bed material, and supplies a fuel or / and an object to be treated to the fluidized bed for combustion treatment,
A fluidized bed boiler comprising a residue removal mechanism that collects and removes the residue of the object to be treated in the combustion treatment as bed ash together with a bed material. The residue removal mechanism includes:
A floor portion of the furnace having a plurality of gaps;
The fluidized bed boiler according to claim 1, further comprising a separation mechanism that separates and removes the residue from the bed ash that has passed through the floor portion. The fluidized bed boiler according to claim 2, further comprising a circulation mechanism that supplies the bed ash, which has become a bed material by removing residues by the separation mechanism, into the furnace again. The fluidized bed boiler according to claim 2 or 3, wherein the residue removing mechanism includes a hopper mechanism that collects the bed ash that has passed through the floor and supplies the bed ash to the sorting mechanism. The fluidized bed boiler according to claim 1, wherein the residue removing mechanism includes a cooling mechanism that cools the bed ash. The cooling mechanism is
A first cooler for cooling the bed ash immediately after passing through the floor;
The fluidized bed boiler according to claim 5, further comprising a second cooler that further cools the bed ash immediately before being supplied to the sorting mechanism. The fluidized bed boiler according to any one of claims 4 to 6, wherein the residue removing mechanism includes a core that is disposed inside the hopper mechanism and allows the bed ash to pass through the entire surface of the floor portion evenly. . The fluidized bed boiler according to any one of claims 2 to 7, wherein the floor portion includes a plurality of diffuser tubes or diffuser nozzles for supplying the combustion gas to the furnace. The fluidized bed boiler according to any one of claims 2 to 8, wherein the residue is a metal material, and the separation mechanism is a magnetic separator that separates and removes the metal material from the bed ash by magnetic force.

Images