JPS6040886B2 - Fluidized bed thermal reactor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluidized bed thermal reactor such as a fluidized bed incinerator or a fluidized bed pyrolysis furnace.

BACKGROUND ART Incineration, thermal decomposition, etc. are performed to treat municipal waste, and fluidized bed incinerators or fluidized bed thermal decomposition furnaces are used for efficient treatment. In these treatments, non-combustible materials such as cans and bottles contained in the municipal waste placed in the fluidized bed usually accumulate at the bottom of the furnace because they require a much higher fluidization speed than the fluidized media. In order to maintain the fluidized plow condition and enable continuous operation, it is necessary to remove non-combustible materials, and in order to facilitate the removal of non-combustible materials, a A diffuser pipe 2 is provided, and a fluidized bed 3 is provided above the diffuser pipe 2.
An incinerator that performs incineration with a packed bed 4 formed below can be seen.

Here, 5 is an input port for municipal waste, etc., 6 is an outlet for in-furnace gas, 7 is a discharge port for incombustible materials and fluidized media, 8 is a discharge feeder, and 9 is a cooling device that bypasses a part of the fluidizing air. air inlet. In such conventional fluidized bed incinerators, most of the input municipal waste is incinerated and turned into ashes, but some of the waste, especially those with large particle sizes, remain fluidized with the fluidized medium. (Because it easily falls, it comes into contact with the fluidized bed only for a short time when it sinks from the top to the bottom of the fluidized bed. Therefore, the char remains in the state of unburned and carbonized remains, and is placed in the packed bed below the diffuser pipe 2 along with incombustibles. I end up making a short pass into the 4.

Therefore, the combustion materials continue to burn in the packed bed 4, and in the packed bed 4, there is no effect of hawk worship as in the fluidized bed 3, so the packed bed 4 locally becomes abnormally high temperature, and on the other hand, the municipal waste Since salts such as NaCI contained in the packed bed 4 react with the sand of the fluidizing medium and lower the melting point of the sand, there is a possibility that the sand in the packed bed 4 becomes clinker and solidifies.

In order to prevent this and also to protect the discharge feeder 8 etc. from the heat, it is necessary to blow in a large amount of cooling air from the cooling air inlet 9, but this reduces the amount of fluidizing air from the air diffuser 2. , there was a risk that the flow condition would deteriorate. In addition, in order to prevent the generation of clinker, incombustible materials are removed at high speed and the amount of removal is increased, which means that a large amount of sand must be circulated, resulting in large heat loss. The capacity of the transport means increases.

At the same time, since the residence time in the packed bed 4 is shortened, the amount of unburnt materials discharged together with the noncombustible materials increases. These problems occur because large particles are mixed in the municipal waste, so a process is required to crush the municipal waste into small pieces, for example, 50 to 80 pieces, before incineration. Therefore, this crushing process required large equipment and power.

In order to incinerate municipal waste containing large particle sizes without increasing the crushing process, it is necessary to lengthen the residence time of municipal waste in the fluidized bed 3, but to do this, the height of the fluid must be increased. However, a high-pressure blower was required, which also resulted in an increase in equipment and power.

By increasing the velocity of the air from several tracheas in the peripheral area, the present invention, except for the above-mentioned points of the conventional method, can perform particularly fine crushing in advance even in a workpiece containing a mixture of large particle sizes. The object of the present invention is to provide a fluidized bed thermal reaction device that does not require the use of heat treatment, and can completely perform combustion and thermal decomposition, thereby significantly reducing the amount of untreated material discharged to the outside. .

In the present invention, a furnace body is provided with an inlet for processing material and an outlet for in-furnace gas, and several air pipes are provided in the lower part of the interior of the furnace body for ejecting fluidizing gas from a large number of small holes, In an apparatus in which a residual liquid discharge port is provided at the bottom, a fluidized bed is formed above the aeration pipe, and a packed bed is formed below the aeration pipe to perform thermal treatment of the material to be treated, the apparatus is located close to the bottom of the aeration pipe. A fall prevention plate is provided that extends continuously from the center to the vicinity of the side wall, and the aeration pipe is configured to control the velocity of the gas ejected from the small hole of the aeration tube to the small hole near the center of the interior of the furnace body. This is a fluidized bed thermal reactor characterized in that the diffuser tube is larger in the small hole near the periphery than in the periphery.

The present invention will be explained with reference to the drawings based on examples.

In FIG. 2, parts having the same reference numerals as those in FIG. 1 have similar structures and functions. A fall prevention plate 10 is placed below the air diffuser 2.
is provided.

The speed of the airflow ejected from the small holes on the outside of the diffuser tube 2 is higher than the speed of the inside one, and due to this effect, the fluidized medium in the fluidized bed 3 forms a swirling flow that circulates symmetrically in an almost vertical plane. It becomes and flows. Therefore, a flow of the fluid medium is generated outward from the center on the fall prevention plate 10, and due to this flow, the non-flammable matter that has fallen and accumulated on the fall prevention plate 10 is gradually moved outward. In order to change the airflow ejection speed of the holes 4 of the air diffuser 2, for example, a structure in which the size of the small hole is changed (the larger the hole diameter, the larger the air flow speed), or / for each air diffuser. For well-known jetting speed adjustment, such as a structure in which gas is supplied via a valve and the supply amount is varied for each diffuser pipe by restricting the valve (the larger the combined amount, the higher the jetting speed). Just use any means. In this way, if the air velocity of the outer air diffuser is made higher than the air velocity of the inner air diffuser near the center, the fluid medium on the outside will be actively blown up, and the density of the fluid medium will become smaller, causing the center The nearby lower fluid medium flows outward,
Furthermore, it is blown up by high-speed air currents on the outside. On the other hand, since the height of the fluidized bed is higher on the outside than on the inside, the fluid medium flows from the outside to the inside in the upper part of the fluidized bed.
In this way, a swirling flow that circulates symmetrically as shown by the arrows in FIG. 2 is generated in a substantially vertical plane. Due to the action of this fall prevention plate 10, unburned particles of large particle size that have passed through the fluidized bed 3 and fallen between the aeration pipes 2 do not directly enter the packed bed 4 through a short path, and the fall prevention plate 10.

The accumulated unburnt material gradually moves outward due to the swirling flow, while combustion continues. The unburned matter that has moved to the outer edge of the fall prevention plate 10 sinks here for the first time and enters the packed bed 4, but by this time a certain amount of time has already passed and combustion has progressed, and the unburned matter has moved to the fluidized bed 3 again. Since the combustion of the part caught up inside is significantly promoted, the amount of unburned part entering the packed bed 4 is extremely small. In addition, the air diffuser 2 and fall prevention plate 1
There is a gap between 0 and 0, and the movement of unburned substances is smooth, and there is no risk that the moving unburned substances will interfere with the fumes from the aeration pipe 2, and the fluidized bed will not be obstructed.

Therefore, there is no risk of causing problems as described in the prior art example, and therefore, there is no need to crush the municipal waste into small pieces in advance, and it is only necessary to break the bags after collection, so a fine crushing process is not necessary.

Further, in this embodiment, since the incombustible material is moved in the horizontal direction by the swirling flow of the fluid medium, the inclination of the fall prevention plate 10 may be gentle.

Therefore, the height of the moving bed section (packed bed section) containing the fluid medium can be reduced, which helps in reducing the weight. In addition, the flow of the fluidized bed due to the swirling flow is improved, and in addition, the effect of classifying the non-combustibles and the fluidized medium on both sides is increased, and the amount of fluidized media circulated outside the furnace (extracted amount) is reduced. FIG. 3 shows another embodiment, in which a turning slope 11 is provided on the inner circumferential wall of the furnace body 1 above the air diffuser 2 to turn the rising air flow from the outer air diffuser 2 toward the center of the furnace. It is provided as an internal circulation mechanism, the action of which produces a swirling flow of the fluid medium that circulates symmetrically in an approximately vertical plane.

Due to the action of this swirling flow, a flow of the fluid medium from the center to the outside is generated above the fall prevention plate 10, and
The non-flammable matter that has fallen and accumulated on the surface moves outward, and has the same effect as the previous embodiment. In place of the turning slope 11, the same effect can be obtained even if the upward flow is turned by a floor airflow jetting out almost horizontally from the peripheral wall toward the center.

According to the present invention, even if the processed material contains large particles, it can be completely processed by combustion or thermal decomposition without performing particularly fine crushing in advance, and the amount of discharge force for unprocessed material is extremely small. It is an object of the present invention to provide a fluidized bed thermal reactor which is capable of increasing effective treatment by reducing the amount of waste extracted, and which makes it possible to reduce the size, weight and power of equipment by eliminating the need for a detailed crushing process. This has a very large practical effect.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional explanatory diagram of a conventional example, and FIGS. 2 and 3 are cross-sectional explanatory diagrams of different embodiments of the present invention. 1...furnace body, 2...diffuser pipe, 3...
...Fluidized bed, 4...Packed bed, 5...
Inlet port, 6... Outlet, 7... Outlet port,
8... Discharge feeder, 9... Cooling air inlet, 10... Fall prevention plate, 11... Turning slope. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. An exhaust pipe for spouting fluidizing gas from a number of small holes is provided in the lower part of the interior of the furnace body, which is equipped with an inlet for the material to be treated and an outlet for the gas in the furnace, and In an apparatus in which a residue discharge port is provided at the lowest part of the body, a fluidized bed is formed above the aeration pipe, and a packed bed is formed below, the material to be treated is subjected to thermal reaction treatment. A fall prevention plate that extends continuously from the center to the vicinity of the side wall is provided nearby, and the air diffuser tube controls the velocity of the gas ejected through the small holes of the air diffuser tube to a small area near the center of the interior of the furnace body. A fluidized bed thermal reactor characterized in that the diffuser tube is larger in the small hole near the periphery than in the hole. 2. An aeration pipe for ejecting fluidizing gas from a number of small holes is installed in the lower part of the interior of the furnace body, which is equipped with an inlet for the material to be treated and an outlet for the gas in the furnace, In this apparatus, a fluidized bed is formed above the aeration pipe, and a packed bed is formed below the aeration pipe, and a thermal reaction treatment is performed on the object to be treated. A fall prevention plate is provided that extends continuously to the vicinity of the side wall, and the aeration tube is configured to reduce the velocity of the gas ejected from the small hole of the aeration tube toward the periphery of the furnace body rather than at the small hole near the center of the interior of the furnace body. The air diffuser pipe is larger at the small holes near the air diffuser, and is provided on the peripheral wall inside the furnace body above the air diffuser pipe, and includes a turning slope that diverts the upward flow and directs it to the center inside the furnace body. A fluidized bed thermal reactor characterized by: