JPH0616248Y2 - Fluidized bed combustor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a fluidized bed combustor suitable for burning solid fuel such as coal containing coarse particles and incombustible materials and waste.

[Prior Art] Conventionally, a fluidized bed combustor that burns solid fuel such as coal or waste is well known. For example, a fluidized bed combustor as an incinerator for municipal waste as waste ejects air from an air supply pipe provided in the lower part of the main body of the combustor, supplies the incineration material to the air supply pipe, and sands. A fluidized medium such as the above is supplied to fluidize the material to be incinerated and the fluidized medium on the air supply pipe to form a fluidized bed and burn the material to be incinerated for incineration. It is known to take out the fluidized medium together with the fluidized medium, separate it, and circulate the fluidized medium again on the air supply pipe.

(For example, Japanese Unexamined Patent Publication No. 62-182514) Further, as a combustor for incinerating an incineration material containing a coarse incineration object, a fluidized bed combustion section is configured as described above, and a screen tube having an inclined surface is used. At least a part of the screen is arranged so as to be immersed in the flow tube, the supply port of the burned material is located on the high side of the screen tube, and the discharge chute of the non-combustible large foreign matter is connected to the low side to configure the screen. Incinerator and large incombustible foreign matter are separated in the part where the fluidized bed of the pipe moves, and only large incombustible foreign matter is removed to the outside of the equipment on the inclined screen tube. Preventing deposition to maintain fluidization, and to prevent subsequent blockage to the discharge device to enable continuous operation, and use this inclined screen tube as a heat transfer tube,
By changing the depth of the fluidized bed by supplying or discharging the fluidized medium, the area where the screen tube is immersed in the fluidized bed can be changed, and the in-layer burning rate of the incineration object or the in-bed temperature can be controlled. Known fluidized bed combustors are known. (For example, Japanese Patent Application Laid-Open No. 62-17510) [Problems to be solved by the invention] However, in a fluidized bed having a means for discharging and removing coarse incombustibles such as a screen tube as described above. The advantage of being able to separate the incinerator and large non-combustible foreign matter by the movement of the sludge and to slide it on the inclined screen tube upper surface in the fluidized bed, and by using this screen tube as the heat transfer tube, the fluidized bed temperature and the incinerated material Although it has the advantage that the burning rate can be adjusted at the same time, on the other hand, it removes large non-combustible foreign matter on the screen tube in the fluidized bed, which complicates the structure of the fluidized bed combustion part and It has a factor that hinders the stable fluidization of, and adversely affects the stable fluid combustion. Further, this conventional device only discharges large noncombustible foreign matter on the screen tube, and is not designed to completely burn a large burned material on the screen tube.

Further, when removing large non-combustible foreign matters with a screen tube, since the large amount of non-combustible foreign matter is discharged by sliding on an inclined surface, there is also a problem that the degree of discharge is uncertain.

Furthermore, if a slanted screen tube (heat transfer tube) is installed in the fluidized bed, the combustion gas generated in the fluidized bed will easily flow along with the slanted screen tube together with the fluidized medium. There is also a problem that the wear of the screen tube becomes extremely large.

According to the present invention, a coarse burned substance or a coarse burned substance containing an incombustible substance can be burned exclusively in the freeboard portion above the fluidized bed while maintaining an optimum burning temperature suitable for the properties of the burned substance. In addition, the coarse incombustibles can be continuously and forcibly discharged, and the combustibles of a normal size can be combusted in the lower fluidized bed combustion section. In this way, stable fluid combustion is continuously performed by not supplying large bulk fuel or large non-combustible material, and supplying combustible material or incombustible material of a size that does not hinder fluidization stability in the fluidized bed formation part. The purpose is to obtain a fluidized bed combustor that can be operated by

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a fluidized bed combustor for combusting an object to be combusted in a lower portion of a combustor body, and a coarse board to be combusted in a freeboard portion above the combustor. A grate for burning is provided. A large number of coarse incombustibles scraping arms are juxtaposed, and a large number of heat transfer tubes are arranged in parallel between the arms to form a grate surface. The transfer arm is configured to be rotatable in the direction in which the upper end of the arm moves up and down from the upper end of the heat transfer tube to move the incombustibles to the discharge side. If a heat transfer tube is provided in the fluidized bed combustion section, it will be effective as described later.

Further, it is effective that the grate surface of the grate is inclined toward the discharge side.

[Operation] For example, if a large combustible waste mixed with coarse incombustibles such as waste tires, rubber hose with core wire, shredder dust of abandoned cars, etc. is thrown onto the grate provided in the freeboard section of the combustion chamber, this waste will fall to the bottom. The high-temperature atmosphere of the combustion gas rising from the fluidized bed combustion section of the above causes the waste or small waste that has become smaller due to combustion to fall to the lower fluidized bed combustion section where it is fluidized and burned. . Therefore, it is possible to completely separate the combustion of coarse particles and the combustion of small particles at different parts, and it is possible to perform stable fluidization without affecting the fluidized state of the fluidized bed combustion section by the coarse particles, Each combustion action is performed stably. In the grate provided on the freeboard part, the heat transfer tubes and the coarse noncombustible part scraping arms are alternately juxtaposed to form a grate surface, and the scraping arms are ejected by projecting or descending from the top surface of the heat transfer tube. By making it rotatable to the side, the combustion temperature on the grate surface can be adjusted to maintain optimum combustion efficiency, and coarse incombustibles are continuously and reliably discharged to the outside of the device. In addition, it is possible to continuously burn even a burned material that contains a large amount of incombustibles, and the incombustibles and combustibles that have become small lumps due to combustion are reliably dropped below by the movement of the scraping arm. Stable combustion of combusted materials including incombustibles can be performed.

In this case, if a heat transfer tube is installed in the fluidized bed combustion section,
Combustion can be performed in the fluidized bed combustion section and the grate under optimum temperature conditions.

Further, by providing the grate surface so as to be inclined toward the discharge side, the discharge action can be performed more reliably.

Embodiments Embodiments will be described below with reference to the drawings.

FIG. 1 is a vertical cross-sectional view showing an overall structure of a fluidized bed combustor according to an embodiment of the present invention, and FIGS. 2 to 5 are drawings showing a grate used in the fluidized bed combustor of the present invention. 2 is a front view,
3 is a plan view of FIG. 2, FIG. 4 is a left side view of FIG.
FIG. 5 is an enlarged view of a main part (P part) of FIG.

First, the fluidized bed combustor of the present invention will be described mainly with reference to FIG. In addition, in the present embodiment, a case will be described in which the fluidized bed combustor is used as a waste boiler for burning coarse waste and general waste as combustible materials.

As shown in FIG. 1, the combustor body 10 has a fluidized bed combustion section 20 in its lower portion, and the fluidized bed combustion section 20 has sand,
A plurality of air supply pipes 21 provided with air holes for fluidizing a fluid medium such as limestone or ceramic balls are provided so as to traverse the main body 10 in the horizontal direction, and each air supply pipe 21 is provided between them. The non-combustible particles are arranged at intervals so that they can pass downward. Further, a discharge port 20a for discharging the small noncombustible particles descending from the fluidized bed combustion unit 20 and the fluidized medium is provided below the discharge port 20a.
A classifier 23 is provided via the. This classifier 23
The non-combustible material having a large particle size is discharged from the lower discharge port 23b to the outside of the machine, and the fluidized medium having passed through the mesh of the classifier 23 is transferred from the other discharge port 23a to the circulation conveyor 24 and transported, and again. It is returned to the fluidized bed combustion section 20.

A heat transfer tube 22 for adjusting the temperature of the fluidized bed is installed above the air supply tube 21.

Freeboard section (empty tower section) 3 above the fluidized bed combustion section 20
A grate 40 for burning coarse waste is arranged in the approximate center of 0. The grate 40 has a grate surface 40a for placing and burning the coarse waste in the freeboard section 30. The main body 10 is inclined so that the center side of the main body 10 is high and the side wall side of the main body 10 is low. This grate 40
As will be described later in detail, a large number of coarse incombustible substance scraping arms 42 and heat transfer tubes 41 are alternately arranged side by side, and the upper surface thereof forms a grate surface 40a. The scraping arm 42 is
The base end side is rotatably attached to the side wall 10b of the grate chamber 10a which is provided so as to project from the side wall of the combustion chamber body 10 (see FIG. 3), and is arranged at an appropriate interval.
It is rotatably supported by a book arm drive shaft 43. At the lower end of the grate chamber 10a, an incombustibles discharge conveyor 9
0 is provided.

A coarse waste chute 70 is provided on the upper wall of the combustor body 10 facing the grate surface 40a of the grate 40 via an air lock damper 71, and a general waste hopper 80 is provided on the side thereof. It is provided via a shaft screw feeder 81. The inlets of the coarse waste chute 70 and the general waste hopper 80 into the main body 10 are not limited to the upper wall of the main body 10 and may be provided in the side wall. The combustibles fed from the general waste hopper 80 descend while avoiding the grate 40, and are directly fed into the fluidized bed combustion section 20 at the lower part of the main body and burned.

On the other hand, a desulfurization and dechlorination bed 50 for combustion gas is located on the upper side of the combustor body 10, and this floor 50 has a gas dispersion plate 51 provided with a number of distributors 52 having gas supply ports at the bottom thereof. A desulfurizing agent or dechlorinating agent such as limestone is supplied onto the gas dispersion plate 51. The desulfurizing agent or the dechlorinating agent is fluidized by the combustion gas ejected from the distributor 52 to form a fluidized bed, where the sulfur content and the chlorine content in the combustion gas are absorbed. 50
a is a heat transfer tube for adjusting the bed temperature. This heat transfer tube 5
With 0a, the temperature of the bed 50 can be adjusted to the optimum desulfurization / dechlorination temperature.

A waste heat boiler 60 is provided on the downstream side of the desulfurization and dechlorination bed 50 to absorb the retained heat of the combustion gas. Waste heat boiler 60
The gas that has passed through is discharged from the waste gas outlet 10b to the outside of the device and sent to a dust collector or the like (not shown).

Next, details of the grate 40 will be described with reference to FIGS. 2 to 5.

As shown in FIG. 2, the incombustibles scraping arm 42 is formed of a substantially trapezoidal plate whose front view shape is small on the center side of the combustor body 10 and widened on the grate chamber 10a side. Is formed with a relatively narrow width (plate thickness) as shown in FIG. 3, and such an arm 42 is high on the center side of the combustor body 10 and low on the grate chamber 10a side as shown in FIG. As shown in FIG. 3, the freeboard portion 3 of the combustor body 10 is located at the center side of the combustor body 10.
Many are provided side by side so as to cross 0. The large number of arms 42 are rotatably supported by two arm drive shafts 43 rotatably supported on the side walls 10b on both sides of the grate chamber 10a at predetermined intervals in the longitudinal direction of the arms 42. The respective arm drive shafts 43 are a first shaft 43a to which a drive device is connected, and an eccentric plate 43 fixed to the end of the first shaft 43a inside the side wall 10b.
b and a second shaft 43c whose end is fixed to the eccentric plate 43b.

That is, each arm 42 is formed with a hole through which two second shafts 43c penetrating at a predetermined interval on the grate chamber 10a side pass, and at the end of each second shaft 43c. Eccentric plate 43b is fixed to each of the
The first shaft 43a is fixed at a position eccentric (offset) from the mounting position of the second shaft 43c to b, and a deceleration not shown on the end side of the first shaft 43a. A drive device such as a motor with a machine is connected. The two drive shafts 43a and 43c and the eccentric plate 43b are formed in exactly the same manner, and are driven simultaneously.

As shown in FIG. 3, a large number of heat transfer tubes 41 are alternately arranged between the arms 42, and one end of each heat transfer tube 41 is located on the grate chamber 10a side. It branches from the water supply header 41a which is located below the arm 42 and fixedly attached to the grate chamber 10a by a supporting member (not shown), and the other end side is fixed to the combustor body 10 by a supporting member (not shown). Set header 41
connected to b. From the bent portion of the heat transfer pipe 41 on the water supply header 41a side, the auxiliary guide member 4 is inclined at the same inclination as the heat transfer pipe 42.
1c is extended and attached.

A required gap is maintained between the heat transfer pipe 41 and the arm 42 to allow the combustion gas to pass upward from below.

Protrusions 42a are formed on the upper end portion of the arm 42 at predetermined intervals in the longitudinal direction of the arm 42, and for waste that easily rolls down the inclined surface, the rolling can be prevented and a predetermined combustion time can be secured. In addition, the downward movement of the moving arm 42 is applied to the waste that is hard to roll.

The upper surfaces of the heat transfer tube 41, the arm 42 and the auxiliary guide member 41c form a grate surface 40a.

In the grate 40 configured in this manner, when the two arm drive shafts 43 are simultaneously driven to rotate, as shown in FIG. 5, the arm 42 has the protrusion 42a due to the rotating action of the eccentric plate 43b. Each point on the upper surface of 42 is rotated in a circular motion locus. That is, for example, the apex A of the protrusion 42a draws a movement locus that forms a circle B rotating counterclockwise as shown in FIG. That is, the upper end of the arm 42 rises from the upper end of the heat transfer tube 41 while rotating in the direction in which the waste placed on the grate surface 40a should be moved to the descending slope side.
To descend. Combustibles and incombustibles that have become small by combustion while the arm 42 descends fall through between the heat transfer tubes 41, the combustibles are combusted in the lower fluidized bed combustion unit 20, and the incombustibles are removed from there. It is discharged to the outside below and is fed into the classifier 23.

In the fluidized bed combustor configured as described above, the coarse waste is put into the combustor from the chute 70 by the air lock damper and placed on the grate surface 40a of the grate 40 located on the freeboard section 30. Then, it is combusted by the high temperature combustion gas rising from the lower fluidized combustion section 20 to the freeboard section 30. On the other hand, the general waste having a small particle size is thrown into the combustor from the hopper 80 by the twin-screw screw feeder 81, passes by the grate 40, and is directly supplied to the lower fluidized bed combustion unit 20 to flow. The air blown from the air supply pipe 21 together with the medium is fluidized and burned to be incinerated. In the above-mentioned grate 40, the coarse waste that has been burnt on the grate surface 40a and incinerated becomes a small lump, and due to the lateral movement of the moving arm 42, the one that can pass between the heat transfer tubes 41 is downward. And is supplied to the fluidized bed combustor 20 where combustibles are burned there, and the incombustibles pass through the discharge pipe 20a together with the fluidized medium together with the incombustibles in the general waste supplied from the general waste hopper 80. Is put into a classifier 23 outside the apparatus and is screened into an incombustible material and a fluid medium, and the fluid medium is discharged from a discharge port 23a to a circulating conveyor 24.
And is circulated to the fluidized bed combustion unit 20 again for fluidized combustion. The coarse incombustibles remaining after being burnt on the grate surface 40a are generated by the lateral movement of the arm 40.
a is forcedly lowered along the inclined surface, and the grate chamber 10
It is discharged to the outside by the incombustible discharge conveyor 90 at the end of a. By connecting a drive device such as a variable speed electric motor to the arm drive shaft 43 of the grate 40 and adjusting the rotation speed of the arm drive shaft 43, the burned material stays on the grate surface 40a. The time can be adjusted, and different types of combusted materials can be easily combusted in accordance with their combustion conditions. The heat transfer tube 41 forming the grate surface 40a absorbs the combustion heat of the coarse waste burned here and maintains it at a constant temperature. That is, for example, when burning waste having a high calorific value, the combustion heat becomes high, but the temperature can be easily adjusted even in this case. For example, the temperature of the gas passing through the grate 40 is adjusted to 850 to 900 ° C.

Further, the fluidized combustion temperature is maintained at a required temperature by the heat transfer tube 22 provided in the fluidized bed combustion unit 20. For example, the combustion temperature here is maintained at 900 to 950 ° C.

The combustion gas that has passed through the grate 40 passes through the distributor 52 of the gas dispersion plate 51 above it to desulfurize and dechlorinate the bed 5.
It is sent to 0 and enters the fluidized bed by a desulfurization dechlorinating agent such as limestone, and the sulfur content and chlorine content in the gas are absorbed and removed. Further, the combustion gas that has passed through the floor 50 passes through the waste heat boiler 60, where the heat retained therein is absorbed and then taken out from the waste gas outlet 10b to the outside of the dust collector, not shown. It is sent to the processing step.

Although the above examples have described the case of incineration of coarse waste and general waste, the fluidized bed combustor and grate of the present invention are also used for burning coal containing coarse and incombustible materials. Sent.

[Advantages of the Invention] Since the present invention is configured as described above, it has the following excellent effects.

In the fluidized bed combustor according to claim 1, the coarse material is burned on a dedicated grate provided in the freeboard portion, and the combustion material or the like which is burned on the grate into a small mass or a normal combustion material. Can be burned in the fluidized bed combustion section below it,
Each combustion product can be burned by adapting to its combustion conditions in independent parts, and in the fluidized bed combustion part, coarse materials do not obstruct the fluidized bed combustion condition and stabilize the originally highly efficient fluidized combustion. Can be done by Therefore, it is possible to efficiently burn the solid fuel including the coarse material and the waste.

Since the grate surface of the grate is composed of a heat transfer tube and a coarse incombustible material scraping arm, it is possible to adjust the combustion temperature on the grate and generate wastes having different calorific values. It is possible to easily and reliably burn the various types of fuel described above by keeping the fuel at the optimum combustion temperature. At the same time, coarse incombustibles can be removed from the grate, and the combustibles that have become smaller due to combustion can be reliably dropped downward due to the movement of the scraping arm. It is possible to efficiently burn and incinerate wastes containing incombustibles. In addition,
Since the heat transfer tube and the scraping arm that compose the grate surface are not located in the fluidized bed unlike the conventional device, there is no wear phenomenon due to the synergistic action of the combustion gas from the fluidized bed and the fluidized medium, which is advantageous. Is.

In the fluidized bed combustor according to the second aspect, since the temperature of the fluidized bed combustor can be adjusted to the optimum condition, various fuels and wastes having different calorific values can be easily combusted.

In the fluidized bed combustor according to claim 3, since the component to be burned on the grate is provided with a component force that descends in the inclined direction, the movement of the scraping arm in the lateral direction is combined with the movement on the grate surface. It is possible to more reliably discharge the incombustibles remaining after burning, and to surely perform the dropping action of the combustibles, which have become smaller due to combustion, to the fluidized bed combustion section below.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an overall structure of a fluidized bed combustor according to an embodiment of the present invention, and FIGS. 2 to 5 are drawings showing a grate used in the fluidized bed combustor according to an embodiment of the present invention. And the second
The drawing is a front view, FIG. 3 is a plan view of FIG. 2, FIG. 4 is a left side view of FIG. 2, and FIG. 5 is an enlarged view of a main part (P portion) of FIG. 10 ... Combustor body, 10a ... Grate chamber, 20 ... Fluidized bed combustion section, 21 ... Air supply tube, 22 ... Heat transfer tube (fluid section), 30 ... Freeboard section, 40 ... Fire Lattice, 40a ... Grate surface, 41 ... Heat transfer tube, 42 ... Incombustible substance scraping arm, 42a ... Projection, 43 ... Arm drive shaft, 43a ... First shaft, 43b ... Eccentric plate, 43c ... second axis.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-65514 (JP, A) Actually open 57-66324 (JP, U) Actually open 57-132933 (JP, U) Actually open 61- 204121 (JP, U)

Claims (3)

[Scope of utility model registration request] 1. A fluidized bed combustor for burning an object to be burned is provided in a lower portion of a combustor body, and a grate for burning a coarse object to be burned is provided on a freeboard portion above the burner. A large number of arms for scraping incombustibles are juxtaposed, and
A large number of heat transfer tubes are juxtaposed between the arms in parallel with each other to form a grate surface, and the upper ends of the scraping arms are raised and lowered from the upper ends of the heat transfer tubes to discharge the incombustibles. A fluidized bed combustor, wherein the fluidized bed combustor is configured so as to be rotatable in a direction of moving to. 2. The fluidized bed combustor according to claim 1, wherein a heat transfer tube is installed in the fluidized bed combustion section. 3. The fluidized bed combustor according to claim 1, wherein the grate surface is inclined toward the discharge side.