JPS61223421A - Fluidized bed thermal reaction furnace - Google Patents

Abstract

PURPOSE:To permit the super magnification of the size of furnace by a method wherein the furnace is equipped with a dispersing plate, designed so as to have a specified configuration, as the dispersing mechanism of air for the fluidized bed. CONSTITUTION:The furnace is equipped with two sets of dispersing plates 8 for fluidization on the bottom at the left and right sides thereof. The dispersing plates 8 are provided in parallel in the a fluidized bed thermal reaction unit, having both sides rims lower than the central part of the unit and formed into a chevron section symmetrical to the center line, so as to be substantially symmetrical with respect to the center line of the furnace. Incombustible substance discharging ports 42 are provided between respective dispersing plates 8 and respective outside rims while reflecting walls, reflecting the upward stream of fluidized gas and turning the direction thereof toward the center of respective fluidized bed thermal reaction units, are equipped immediately above the side rims of the side of furnace walls of respective dispersing plates 8, further, a material throwing port is provided at the ceiling of the furnace. According to this method, the moving distance of incombustibles may be kept in short and the stagnation of the incombustibles may be prevented even in the furnace having a large width of the furnace whereby the magnification of the size of furnace, which has been impossible so far, may be realized easily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a thermal reactor such as an incinerator or a pyrolysis furnace using a fluidized bed.

[Conventional technology]

As this type of thermal reactor, for example, in incinerators for municipal waste, fluidized bed furnaces, which have better incineration efficiency than stoker furnaces and produce less incineration residue, have recently been used.

At that time, if the material was large enough to become garbage, it would hinder the fluidization of the fluidized medium, so in order to prevent this, it was pre-treated using a crusher before being put into the incinerator. was. Therefore, crushing equipment including a crusher is required, which causes problems in terms of space and cost. In addition, using a shredder can cause problems such as wear and tear on the blades due to non-flammable foreign objects (irons, hammer heads, cannonballs, concrete blocks, etc.) that get mixed into the garbage, and even though they are flammable, Bulky garbage (for example, futons, blankets, fishing nets, etc.) is difficult to crush, which causes many problems, such as increased crushing power or the crusher stopping because it cannot be crushed. Furthermore, in the case of such a problem, the crusher must be disassembled or a person must enter the crusher to manually remove the foreign matter, which increases the effort and cost of maintenance and management, and the time required to troubleshoot the problem. The crushing process had to be stopped, which significantly hindered work efficiency.

On the other hand, in terms of incineration capacity, the maximum capacity of the furnaces in operation at the time was approximately 75 tons/24 hours, and even those under design had a maximum of approximately 150 tons/24 hours, and it was difficult to realize a larger capacity. It was a great turn of events.

In order to solve these problems, the present inventors developed a fluidized bed furnace that does not require pre-crushing treatment and can be made larger, by rotating the fluidized medium in a vertical plane in the furnace space. Japanese Unexamined Patent Application Publication No. 1983-1983 has solved the drawbacks of the conventional method by circulating the fluidized medium to form a fluidized bed and a moving bed.
He invented a fluidized bed thermal reactor as seen in Japanese Patent No. 124608.

[Problem that the invention seeks to solve]

However, even with the fluidized bed furnace disclosed in Japanese Patent Application Laid-Open No. 57-124608, it was thought that about 300 t/d was the practical limit in terms of increasing the size.

For example, in a municipal waste incinerator, the hearth load of a fluidized bed furnace is generally considered to be about 450 kg/m"h. On the other hand, the fluidized bed thermal reactor (unexamined patent application In Japanese Patent No. 57-124608), a swirling flow is generated by a combination of a moving bed and a fluidized bed as shown in Fig. 11, and large garbage, heavy non-combustible materials, etc. are moved laterally without settling in the hearth. There is a limit to the width of the furnace in order to carry out effective combustion and discharge of incombustibles, and the width of the furnace is L = 4m.
is the limit.

Here, for example, a 1000t/d furnace is 450Kg/m"h
Calculating the hearth area based on 24h 0
．． 45t/m” h -92.6m” A=92.6m” divided by furnace width L-4m is approximately 23.2m
becomes. The hearth module at this time becomes an extremely elongated hearth as shown in FIG. 12, and has an unrealistic rectangular shape.

The present invention aims to eliminate these drawbacks and provide a fluidized bed thermal reactor that can be made extremely large.

[Means for solving problems]

The present invention includes a fluidizing dispersion plate, and the dispersion plate has both side edges lower than the center and has a chevron-shaped cross section that is almost symmetrical with respect to the center line. A common incombustible material discharge port is provided between each of the dispersion plates, and a noncombustible material discharge port is provided on each outer side edge of the furnace. It is characterized by a reflecting wall that reflects and diverts the upward flow of fluidized gas toward the center of each fluidized bed thermal reaction section directly above the side edge of the wall, and a raw material inlet in the furnace ceiling. This is a fluidized bed thermal reactor.

(Example) The present invention will be described with reference to the drawings regarding an example in which a dispersion plate is used as a dispersion mechanism for fluidizing air in a municipal waste incinerator.

Fig. 1 shows an example of a municipal waste incineration facility using a fluidized bed incinerator 6, in which waste stored in a garbage pinto 1 is dumped into a hopper 4 by a packet 3 of a crane 2, and a feeder is used as a feeding device. It is designed to be supplied to the incinerator 6 by M5. In the incinerator 6, the fluidizing gas supplied by the blower 7 is ejected upward from the distribution plate 8 into the furnace, hits the inclined wall 9 and becomes a swirling flow lO in the vertical plane, causing the fluidized medium such as sand to flow along this flow. A swirling fluidized bed is formed. Furthermore, as will be described later, a descending moving bed is formed in the furnace, and the swirling fluidized bed and descending moving bed allow the waste to burn well in a short period of time, and even if crushing is not performed in advance, the waste remains at a high temperature without impeding fluidization. Combustion efficiency can be obtained.

11 is a combustion exhaust gas duct, 12 is a non-combustible material discharge device, 13
1 is a vibrating sieve, 14 is a conveyor for discharging lumpy noncombustibles, and 15 is an elevator for collecting a fluid medium such as sand.

The structure of the feeding device 5 is, for example, as shown in FIG. 2 and Part 3, a hopper 4 is connected to the conveyor case 20 via a waste inlet 16, and waste outlets 17 are provided at both lower ends. It is being Inside the conveyor case 20, the raw materials introduced near the center are twisted in opposite directions from the center to the left and right to be transported by distributing them to the left and right.
At least two screws 2 that rotate in opposite directions to each other, perform normal rotation such that their upper sides approach each other during normal operation, are held parallel to each other, and are twisted in opposite directions.
1.22 is provided. The pitch of the blades 23, 24 of the screw 21, 22 is larger at the pinch near the outlet 17 than at the pinch near the inlet 16.

In addition, at the continuous points of the screws twisted in the opposite direction at the center of the turret, the outer diameter is gradually increased to prevent dust from getting caught.

One screw 22 is supported by bearings 25 and 26 at a fixed position relative to the conveyor case 20, and is directly rotated by a motor 27. Screw 2 during normal operation
2 rotates in a normal counterclockwise direction when viewed from the motor 27 side, and the screw 21 rotates in a normal clockwise direction.

The screw 21 is supported by a cylinder 28.29 on a displacement bearing 31.32 which moves along a guide rail 30, as shown in FIGS. 3 and 4. Since the cylinders 28, 29 are thus configured to have equal distance displacements as described below, the screw 21 moves parallel to the screw 22 and the center distance adjustment is 2.
It is scheduled to be held from 12 to 12.

The shaft ends of the screws 21 and 22 on the motor 27 side are connected to links 33, 34 and gears 35.34, as shown in FIGS. 5 and 6.
36, 37, and 38, the screw 21 continues to be driven and rotated in the opposite direction to the screw 22 even while the interaxial distance is changing from 11 to 18.

If dirt gets caught between the screws 21, 22, the dirt will cause the screws 21, 22 to receive an expanding force that increases the distance between their axes. .22 and other parts, which must be prevented.

In order to meet these requirements, the distance between the shafts is adjusted as shown in Figure 7 (a) and (b).That is, the distance between the shafts is set to the minimum distance between the shafts L% and the maximum distance between the shafts at steady state tm 1g. ,
The expansion force caused by the debris 39 caught between the screws 21, 22 is detected as a hydraulic pressure in the cylinders 28, 29. For example, as will be described later, an allowable enlarging force is set as an allowable value of the enlarging force in a hydraulic circuit.

However, during normal operation, as shown in Figure 7 (a), crushing and bag tearing are carried out at the minimum center-to-center path M a r, and large debris 39 or lump-like incombustibles enter, and the expanding force exceeds the allowable expanding force. The distance between the axes has increased, and it is 21-1! The screws 21 and 22 continue to rotate in the normal direction, both during opening and after opening, until the expansion force drops to the allowable expansion force, and destruction, bag tearing, and transfer are performed continuously.

FIG. 8 shows an example of a hydraulic circuit for performing the above-described inter-axle path Mm node.

Next, the incinerator 6 will be explained.

As shown in FIG. 9, two sets of air dispersion plates 8 for fluidization are installed side by side on the left and right at the bottom of the incinerator 6. It is formed in a chevron-shaped cross section (roof-like) that is almost symmetrical with respect to the line. The incombustible material discharge port 42 is connected to both side edges, and the incombustible material discharge port 4
Of the two, the one in the center of the furnace is shared at one location.

The fluidized air sent from the blower 7 is placed in the air chamber 43°44
．． The mass velocity (Kg/m" 7/56c) of the fluidized air jetted out from the air chambers 43 and 45 on both side edges is equal to that of the fluidized bed. However, the mass velocity of the fluidized air ejected from the central air chamber 44 is selected to be smaller than the former.

For example, the mass velocity of the fluidized air jetted out from the air chamber 43.45 is 4 to 200 mf, preferably 5 to 10 Gmf, whereas the mass velocity of the fluidized air jetted out from the air chamber 44 is 0.5 to 30 mr, preferably is selected from 1 to 2.50 mf. where IGmf is the fluidization starting mass velocity.

An arbitrary number of air chambers is selected for each distribution plate 8, and even when there are a large number of air chambers, the mass velocity of the fluidized air is small near the center and large near both side edges. do.

Moreover, right above the air chamber 43 on the furnace wall side at the side edge of the dispersion plate 8,
A sloped wall 9 is provided as a reflection wall that blocks the upward flow path of the fluidized air and reflects and diverts the fluidized air toward the center of the furnace. A sloped surface 46 is provided having a slanted surface 46 to prevent the flow medium from accumulating. Further, the inclined wall 9 may be a wall body made of a metal pipe, and water may be passed through the pipe to generate steam or hot water.

The inclination of the dispersion plate 8 is preferably about 5 to 15 degrees, and the inclination of the inclined wall 9 is preferably about 10 to 60 degrees with respect to the horizontal.

Furthermore, the furnace ceiling 47 is provided with at least l or more raw material input ports 48 connected to the outlet 17 of the dust supply device 5.

Next, the operation of the incinerator 6 will be explained. Fluidized air is sent in by the blower 7 and is blown out from the air chambers 43 and 45 at a large mass velocity and from the air chamber 44 at a small mass velocity.

In a normal fluidized bed, the fluidized medium moves up and down violently like boiling water to form a fluidized state.
The fluid medium above the air chamber 44 does not move violently up and down,
Forms a moving bed in a weakly fluid state. The width of this moving layer is narrow at the top, but due to the effect of the inclination of the dispersion plate 8, it widens slightly at the bottom, and part of the bottom reaches above the air chambers 43° 45 on both sides. Therefore, it receives a jet of air with a large mass velocity and is blown up. Since some of the fluid medium at the skirt is removed, the layer directly above the air chamber 44 will fall under its own weight. A fluidized medium from a fluidized bed with a swirling flow 10 is replenished and deposited above this layer as will be described later. By repeating this process, the region of the fluidized medium above the air chamber 44 almost comes together to form a descending moving layer that gradually descends.

The fluidized medium that has moved above the air chambers 43 and 45 is blown upward, but in particular the fluidized medium above the air chamber 43 hits the inclined wall 9 and is reflected and turned toward the center of the furnace as it rises, causing a rapid increase in the cross section inside the furnace. As a result, the air loses its upward speed, falls to the top of the downwardly moving layer, gradually descends, reaches the bottom, and is blown up again to circulate. A part of the fluidized medium swirls in the fluidized bed as a swirling flow IO, and in the center of the furnace, fluidization is performed only in the upper and lower portions, similar to a normal fluidized bed.

That is, the swirling flow 10 of the fluidized medium flows through the air chamber 43 on the furnace wall side.
Since there is no barrier at the top of the air chamber 45 at the center of the furnace, the state is the same as that of a normal fluidized bed with upstream and downstream flow.

The waste input into the incinerator 6 in this state from the raw material input port 48 usually descends to the top of the fluidized bed. Among the garbage, those with relatively high specific gravity are usually taken into the fluidized bed near the center, and those that are easily combustible are combusted. Flame-retardant materials are partially dried or combusted and then diffused into the swirling flow 10. Also, among the trash, relatively light specific gravity is usually not caught up in the fluidized bed and is blown away. Those that are lost and burnt in the freeboard, and those that cannot be completely burnt diffuse into the swirling flow section, fall, and are caught up in the swirling flow 10. In the swirling flow section 10, the flow of the fluid medium flows in a concentrated direction from the outside toward the center, so that the debris is caught up in this flow and sucked into the top of the downwardly moving bed. Therefore, even light materials such as paper can be reliably taken into the descending moving bed, so that the paper burns on the sand without contributing significantly to the heating of the fluidized medium, as in a conventional fluidized bed. This makes it possible to reliably heat the fluidized medium by performing combustion in the descending moving bed and the swirling flow IO.

Partial thermal decomposition occurs in the descending moving bed and combustible gas is generated.The generated combustible gas diffuses horizontally and enters the fluidized bed where it is combusted, and its heat is used to heat the fluidized medium. Effectively useful.

When heavy and large objects such as bottles and irons are dropped onto the surface of the normal fluidized bed in the center of the furnace, these objects flow from the moving bed while being supported by the upward currents blown up in the air chamber 45. As the sand moves laterally, it moves to the incombustible material discharge port in the center of the furnace.
Although this movement is slower than the movement of the sand at the bottom of the reflecting wall, it is constantly moving along the slope of the dispersion plate, so it does not impede fluidization or generate tarinkers.

Therefore, even if the combustible material is quite large, it will be dried, gasified, and combusted as it moves along the slope of the distribution plate, and most of it will be combusted by the time it reaches the non-combustible material outlet in the center of the furnace. Since it is broken into small pieces, it does not interfere with the formation of a fluidized bed.

Therefore, even if the garbage is not crushed in advance using a crusher, it is sufficient to break the bags using the feeding device 5, and the crusher and crushing process can be omitted, resulting in a compact device.

In addition, since the waste thrown into the descending moving bed is quickly diffused into the fluidized medium, the combustion efficiency is increased.

The non-combustible materials supplied through the supply device 5 are distributed to the dispersion plate 8.
It descends and moves horizontally on both sides of the building, but at this time, it does not adhere to non-combustible materials or combustible materials that are integrated with it (such as the covering of electric wires, etc.)
will burn out. The non-combustible materials that have reached the hem reach each non-combustible material discharge port 42 due to the lateral movement of the fluid medium and the inclination of the dispersion plate 8, and are smoothly discharged.

Also, looking at the hearth module, 1000 t/
If the hearth module is calculated for the d furnace, the hearth area -
92.6m", whereas in the conventional example it is 4m (
Hearth width) x 23.2m (Hearth length) (Figure 12)
On the other hand, as shown in Figure 10, 8m (hearth width) x 11
．． The furnace has a well-balanced shape of 6m (hearth length), and has a 1o
It is possible to easily create an ultra-large reactor of the order of ooc/d.

〔Effect of the invention〕

As described above, according to the present invention, in an incinerator or pyrolysis furnace that efficiently burns all kinds of materials to be combusted, such as municipal waste, sludge, and coal, it is possible to
In addition to the various effects shown in the publication, it is possible to keep the moving distance of incombustibles short and prevent the accumulation of incombustibles even in a furnace with a large furnace width, and it is possible to improve the width of the furnace, which was previously considered impossible. This has the extremely beneficial effect of making it possible to easily shape the material.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a cross-sectional front view of a waste incinerator, FIG. 2 is a vertical cross-sectional front view of a feeding device, FIG. 2 figures! Arrow view, 5th
The figure is a sectional view taken along the line nn of Fig. 2, Fig. 6 is a view at another point in time, Fig. 7 (a) and (b) are cross-sectional views of the screw in different steps, and Fig. 8 is a hydraulic circuit diagram. , FIG. 9 is a longitudinal sectional view of the incinerator, FIG. 10 is a plan view and side view of the hearth module of the present invention, FIG. 11 is an explanatory view of the flow state in the furnace, and FIG.
2(a) and 2(b) are a plan view and a side view of a conventional hearth module. l...garbage bit, 2...crane, 3...bucket, 4...hopper, 5...dust supply device, 6...
Incinerator, 7...Blower, 8...Dispersion plate, 9...Slanted wall, 10...Swirl flow, 11...Combustion exhaust gas duct, 12...Incombustible material discharge device, 13...・Fi moving sieve, 1
4...conveyor, 15...eleheta, 16...
Inlet, 17... Outlet, 20... Conveyor case, 2
1.22...Screw, 23.24...Blade, 2
5.26...Bearing, 27...Motor, 28.29.
...Cylinder, 30...Guide rail, 31.32.
...Moving bearing, 33.34...Link, 35,36,
37.38... Gear, 39... Garbage, 42... Incombustible material discharge port, 43° 44.45... Air chamber, 46...
- Inclined surface, 47...Ceiling part, 48...Raw material input port.

Claims (1)

[Claims] 1. A fluidizing dispersion plate is provided, and the dispersion plate has a fluidized bed heat reaction part formed in a chevron-shaped cross section that is substantially symmetrical with respect to the center line, with both side edges lower than the center part. , are arranged in parallel at the bottom of the same furnace almost symmetrically with respect to the furnace center line, and a common incombustible material discharge port is provided between each of the dispersion plates, and a noncombustible material discharge port is provided at each outer side edge, and each of the above-mentioned A reflecting wall is provided directly above the side edge of the distribution plate on the furnace wall side to reflect and divert the upward flow of fluidizing gas toward the center of each fluidized bed thermal reaction section, and a raw material inlet is provided in the furnace ceiling. A fluidized bed thermal reactor characterized by: 2. The fluidized bed thermal reactor according to claim 1, wherein at least one raw material inlet is provided.