JPH03158603A - Fluidized bed type burner - Google Patents

Abstract

PURPOSE:To maintain the state of preferable fluidization in heating medium particles with no influence of some dispersion holes that are more or less clogged by arranging in multiple stages the dispersion holes which pierce through the furnace wall substantially horizontally at the bottom section and forming a gas chamber which surrounds the outside opening sections of the dispersion holes on the outside of the bottom section of the furnace wall. CONSTITUTION:Dispersion holes 18 are formed in multiple stages in the furnace wall 10a of a furnace 10 at the lower section and they are arranged, for instance, radially. Respective gas chambers 19 that surround the outside opening sections of the dispersion holes 18 are mounted on the outer circumference of the furnace wall 10a. The flow rate of the gas that is delivered from a blower 26 is regulated by a regulating valve 25 and the gas is supplied to the gas chamber 19 through supply pipes 24. After the pressure of the gas is regulated there to a certain extent, the gas is blown out into the fluidized bed through the dispersion holes 18. With this arrangement it is possible to maintain a preferable flow of heating medium particles without influence from the dispersion holes 18 which are more or less clogged, and, further, to let the ash, etc., that invade from the dispersion holes 18 stay in the gas chambers and prevent them from flowing further into the upstream side.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a fluidized bed combustion device in which dispersion holes are provided at the bottom of the furnace wall of a combustion furnace for feeding gas into a fluidized bed in the combustion furnace. It is.

(Prior art) Conventionally, fluidized bed combustion devices used for boat fishing have dispersion holes at the bottom of the combustion furnace for feeding gas vertically into the fluidized bed in the combustion furnace, and have multiple The dispersion plate with dispersion holes formed therein is placed at the bottom of the fluidized bed so as to cover most of the inside of the furnace, and the outlet for taking out combustion ash, combustion garbage, lumps of solid particles, etc. is located in one part of the dispersion plate. or both ends. With this configuration, the gas introduced from below the dispersion plate is sent vertically into the fluidized bed from below through the dispersion holes of the dispersion plate, and as a result, the heat filled in the fluidized bed is Media particles (e.g. average particle size 0.3~
Sand, alumina, silica particles, etc. of about 0.8 mm) and the combustion material are stirred in a fluidized bed with a flow of heat carrier particles, and the combustion material comes into contact with the high temperature heat carrier particles, causing It heats up quickly and burns efficiently.

However, in this type of combustion device,
Because the dispersion pores extend vertically, when the equipment is stopped, there is a very high probability that the heat carrier particles that were circulating in the fluidized bed during operation will freely fall and enter through the dispersion pores. At the same time as such particles enter, the particles gradually adhere to the dispersion pores. Therefore, by repeatedly using a combustion furnace, the air flow path downstream of the distribution plate and the distribution holes of the distribution plate are gradually blocked by heat transfer particles, etc., and as a result, most of the distribution holes are occupied by the heat transfer medium. It is blocked by particles and the like, preventing the desired gas from being supplied into the furnace, resulting in equipment failure.

In addition, in the above-mentioned type of combustion device that blows gas vertically upward, when the gas is made to flow at high speed, a local channeling portion of the fluid is created in the heat carrier particle layer above the dispersion hole, resulting in a fluidized bed. In some cases, it may not be possible to properly circulate the heat transfer medium particles within the heat exchanger.

Furthermore, the dispersion plate is arranged to cover almost the entire area of the bottom of the furnace, and the outlet for removing ash, etc. is provided in a part of or around the dispersion plate, but since the dispersion hole requires a certain area, it is not necessary to It is not possible to form a large outlet, resulting in problems such as poor ash removal efficiency.

Therefore, a fluidized bed combustion apparatus was devised that had horizontal dispersion holes instead of the vertical dispersion holes described above. This horizontal distribution hole type fluidized bed combustion device consists of a distribution hole formed at the bottom of the combustion furnace, a combustion gas outlet pipe installed at the top of the combustion furnace, and a combustion material input pipe installed at the center of the combustion furnace. , and an ash outlet formed at the bottom of the combustion furnace.

The dispersion holes used in this device are configured such that a plurality of dispersion holes are arranged in the circumferential direction so as to penetrate the furnace wall substantially horizontally. The gases collide with each other in the center, causing an updraft and creating a fluidized state within the fluidized bed. As a result, the heating medium particles and the combustion materials filled in the fluidized bed are stirred within the fluidized bed by the flow of the heating medium particles, and
The combustion material is rapidly heated as it comes into contact with high-temperature heat transfer particles, resulting in efficient combustion.

As mentioned above, by providing horizontal dispersion holes at the bottom of the furnace wall, almost the entire bottom of the furnace can be exposed to the ash removal port, so incombustibles and other substances that are likely to exist below in the furnace can be removed. Coarse lumps such as heating medium particles can be efficiently and selectively discharged from the outlet. In addition, horizontal dispersion holes (
Unlike the vertical dispersion hole (former conventional example), the latter (conventional example) is arranged almost perpendicularly to the furnace wall, so that when the operation is stopped, free-falling heat transfer particles, etc. are removed from the dispersion hole. There is little risk of it entering or adhering to the dispersion hole.
Therefore, the number of times the dispersion hole is cleaned can be significantly reduced, and the number of inspection operations can also be reduced.

(Problem to be Solved by the Invention) However, in the -stage type dispersion hole, smooth circulation of the heat transfer medium particles is achieved only when the amount of gas blown out from the return is balanced. When heat transfer particles, etc. adhere to some of the dispersion holes, the amount of gas blown out from the clogged dispersion holes decreases, resulting in uneven gas flow within the fluidized bed. Non-uniform circulation of the heat transfer medium particles will result in hindering efficient combustion of the combustible material.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a fluidized bed combustion apparatus that is not affected by clogging of the dispersion holes and is capable of forming a desired flow of heat medium particles within the fluidized bed.

(Means for Solving the Problems) In order to achieve the above object, the fluidized bed combustion apparatus of the present invention has dispersion holes for feeding gas into the fluidized bed in the combustion furnace at the bottom of the furnace wall of the combustion furnace. The furnace wall is provided in multiple stages, and the furnace wall is substantially horizontally penetrated, and a gas chamber surrounding the outer opening of the distribution hole is formed adjacent to the outside of the bottom of the furnace wall, so that the gas blown out from the distribution hole is It is characterized by providing means for individually controlling each stage.

(Function) According to the fluidized bed combustion apparatus configured as described above,
Dispersion holes penetrating the furnace wall substantially horizontally are provided in multiple stages, thereby making it possible to maintain a suitable flow of heat carrier particles without being affected by some clogging of the dispersion holes.

In addition, by forming a gas chamber that surrounds the outer opening of the dispersion hole adjacent to the outside of the bottom of the furnace wall, ash, etc. that enter through the dispersion hole is stopped within the gas chamber, and ash, etc. flows further upstream. It is possible to prevent this from happening. Furthermore, by providing means for individually controlling the gas blown out from the dispersion holes for each stage, it becomes possible to form any desired flow of heat medium particles within the fluidized bed.

(Example) Hereinafter, an example according to the present invention will be described in detail based on the drawings.

As shown in FIG. 1, the fluidized bed combustion apparatus of the present invention includes a combustion furnace 10 constituting the main body of the apparatus, and the inside of this combustion furnace is filled with heat carrier particles 12 to form a fluidized bed 13. ing. Further, a combustion material input pipe 11 for charging combustion material into the fluidized bed 13 is attached to the furnace wall.
An exhaust gas outlet pipe 14 is provided in the upper part of the combustion furnace 10 to guide combustion exhaust gas generated when the combustion material is combusted to the outside of the furnace. A cyclone separator 15 is attached to the exhaust gas outlet pipe 14 to separate powder particles accompanying the exhaust gas. The upper end of this separator is provided with an exhaust pipe 16 for sending out the exhaust gas to the atmosphere or a gas processing device, and a return pipe 17 for returning powder particles such as heat carrier particles separated by the separator to the furnace.

At the bottom of the furnace 10, heat transfer particles 1 are placed in a fluidized bed 13 in the furnace.
Dispersion hole 18 for feeding combustion gas to fluidize 2
and a gas chamber 19 surrounding the outer opening of the dispersion hole;
A gas supply device 20 that supplies gas to this gas chamber is provided. A take-out section 21 for discharging combustion ash and the like is provided at the bottom of the furnace.

The extraction section 21 is constituted by a pair of valves 21a and 21b, and makes it possible to efficiently extract ash and the like from inside the furnace, which has a higher pressure than the outside.

The dispersion holes 18 of the fluidized bed combustion apparatus of the present invention are formed in multiple stages (four stages in this embodiment) in the furnace wall 10a at the lower part of the furnace 10, and are arranged radially, for example, as shown in FIG. Each gas chamber 19 surrounds the outer opening of the six dispersion holes 18.
is defined by a cylindrical surrounding wall 22 attached to the outer periphery of the furnace wall 10a, and a partition plate 23 that partitions the dispersion holes 18 at each stage within the surrounding wall. Therefore, gas chambers 19 having the same volume can be formed independently for each stage. Gas supply device 20 that supplies gas into each gas chamber
, a plurality of gas supply pipes 24 attached to each stage on the outer peripheral wall 22a of the surrounding wall 22, a flow rate adjustment valve 25 provided for each supply pipe 24, and a gas supply pipe 24 for supplying gas to each supply pipe 24. It consists of a gas supply source, for example, a blower 26. Therefore, with the above-described configuration, the flow rate of the gas sent out from the blower 26 is adjusted by the regulating valve 25, and then the gas is supplied into the gas chamber 19 through the supply pipe 24.

Then, the gas whose pressure has been adjusted to a certain degree within the gas chamber 19 having the required volume can be blown out into the fluidized bed through the dispersion hole 18.

Since the blowing speed of gas from the dispersion hole 18 is affected by various factors such as the inlet pressure loss of the dispersion hole, the pressure loss inside the gas chamber 19, and the flow rate of the gas sent out from the blower 26, a flow rate adjustment valve 25 is provided. This makes it possible to optimally control the flow rate of gas sent out from the dispersion holes.

The fluidized bed 13 is adjusted by adjusting the degree of opening and closing of each regulating valve 25 as described above.
For example, the generation of an upward airflow with a uniform flow velocity distribution in the horizontal cross section of the fluidized bed 13 (see Figure 3) can be achieved by sequentially starting from the lowest valve. This is achieved by reducing the opening degree of the valve by a desired amount to gradually reduce the amount of gas blown out from the dispersion hole 18 starting from the lowest stage. As a result of generating such an upward airflow, a uniform temperature distribution is achieved within the fluidized bed, combustion is performed efficiently, and a preferable fluidized state can be obtained even when the combustion temperature limit range is small.

Generation of a relatively large fluidized state within the fluidized bed 13 (fourth
(see figure) is achieved by making the valve opening larger overall than in the case of FIG. 3 and making the flow velocity distribution in the horizontal cross section of the fluidized bed 13 denser in the central portion. As a result of generating such a fluidized state, the movement of the heat transfer medium particles within the fluidized bed increases, and if the heat transfer medium particles attempt to solidify, a fluidized state is obtained that prevents the heat transfer medium particles from solidifying.

Generation of vortex near the vertical central axis in the fluidized bed 13 (fifth
(see figure) is achieved by making the opening of the valves larger overall than in the case of FIG. 4, and by making the flow velocity distribution in the horizontal cross section of the fluidized bed 13 even denser in the central portion. As a result of generating such a vortex flow, a central part where the mixing is intense and a peripheral part where the flow is relatively calm are obtained in the same furnace, so that a fluidized state suitable for two-stage combustion is obtained.

In the fluidized bed combustion apparatus configured as described above, the dispersion holes 18
The gas blown out horizontally in a controlled manner generates the above-mentioned fluidized state or vortex in the furnace, and the combustion is carried by this airflow into the furnace through the combustion material input pipe 11 in the fluidized bed. (combustible materials such as tires, plastics, wood chips, etc.) as well as heat carrier particles 12 are fluidized, and
The combustion material is rapidly heated while coming into contact with the high-temperature heat carrier particles 12.

As a result, combustion exhaust gas is generated at the same time as ash and the like are generated. The exhaust gas generated in this way is transferred to the exhaust gas outlet pipe 14.
The particles are then sent through the cyclone separator 15 into the cyclone separator 15, where relatively large diameter particles such as heat transfer medium particles are separated, and then returned through the return pipe 17 into the furnace. In addition, since the pressure inside the furnace is higher than the outside pressure, the ash accumulated at the bottom of the furnace is removed by first opening the upper valve 21a, and when the ash accumulates on the lower valve 21b, the upper valve 21a is removed. is closed, and then the lower valve 21b is opened to be discharged to the outside of the furnace. By configuring the extraction section in two stages in this way, it is possible to discharge ash, etc. simultaneously with the combustion of the combustible material in the furnace. It can be operated efficiently and continuously without pauses.

Instead of the above-mentioned flow rate adjustment valve 25, each stage of gas supply pipe 2
Even if a fixed orifice with a different setting value is provided in the dispersion hole 18, the flow rate of the gas blown out from the dispersion hole 18 can be adjusted.

It goes without saying that the present invention is not limited to the embodiments described above, and that various changes can be made.

As another embodiment of the gas supply device 20, as shown in FIG. 6, it is also possible to provide a switching valve 28 at the confluence section 27 formed on the upstream side of the gas supply pipe 24 attached to each stage. be. This valve is driven by a motor 29, and the gas supply pipe 24 of each stage is driven by this motor.
and the blower 26 can be individually communicated with each other, and as a result, it is possible to selectively discharge gas from the dispersion holes of a required stage. Further, by configuring the switching valve 28 to be switched over time, it is possible to change the flow rate of gas sent into the gas chamber 19 over time.

In order to adjust the heat dissipation amount and heating amount of the gas sent into the gas chamber 19, for example, as shown in FIG. It is preferable to change it to Further, as shown in FIG. 8, it is preferable to change the volume of the gas chamber 19 for each stage.

As an embodiment in which the blowing speed of gas from the dispersion holes 18 is adjusted for each stage, for example, as shown in FIG.
As shown in FIG. 10, there is one in which the outlet of each dispersion hole 18 is expanded by a predetermined amount. In the former configuration, the gas blown out from the dispersion hole 18 becomes a jet stream, and as a result, it becomes possible to blow out the gas to the vicinity of the center of the fluidized bed, thereby preventing fluidization near the center of the fluidized bed. Can be made larger. With the latter configuration, the gas blown out from the dispersion holes 18 is blown out while being diffused, and as a result, the amount of gas near the furnace wall can be increased.

As an example in which the blowing direction of gas from the dispersion holes 18 is changed for each stage, the dispersion holes 18 may be arranged at a predetermined angle with respect to the vertical central axis of the fluidized bed 13, as shown in FIG. 11, for example. suitable. By changing the angle at which gas is blown from the dispersion holes for each stage, the length of the path of the dispersion holes changes, and the pressure loss within the path can be changed accordingly. The speed can be suitably changed. Furthermore, by changing the blowout angle, the horizontal distribution speed of the jet stream blown out can be changed. Therefore, the horizontal velocity distribution can be suitably adjusted.

An example of an embodiment in which the amount and direction of gas blown out from the dispersion holes are changed for each stage is shown in FIG. 12, for example. In this case, the upper dispersion hole 18 has a reduced diameter on the gas outlet side, the middle dispersion hole 18 has a spherical chamber in the center, and the lower dispersion hole 18 is bent into a V-shape. This shape of the 0-dispersion hole is just an example, and it goes without saying that it is preferable to change the length, thickness, and direction of the path of the distribution hole as appropriate.

Although the gas chamber 19 in FIGS. 9 to 12 is not divided, for example, if the gas chamber is divided into stages as shown in FIG. 7, the blowing of gas from the dispersion holes can be controlled more reliably. It becomes possible.

In order to change the temperature distribution within the furnace and maintain the combustion position of the combustion material in the fluidized bed at a preferred location, it may be necessary to blow cooled or heated gas through the distribution holes. In order to achieve this, for example, as shown in FIG. 13, it is preferable to provide heat exchange means A in addition to the gas supply device 20.

Specifically, the heat exchange means A includes individual medium circulation passages 32 formed so as to surround each gas chamber 19 within the outer peripheral wall 22a of the surrounding wall 22 surrounding the gas chambers 19, and the medium circulation passage 32 formed so as to surround each gas chamber 19. A medium supply device (for example, a pump) 34 for forcibly feeding the medium into the circulation passage, and a heat exchanger 30 for returning the medium that has been circulated through the medium passage to a predetermined medium state. , a pair of pipes 33 that communicate between each medium circulation passage 32 and the medium supply device 34 through the heat exchanger 30, and a medium supply side of the pipes 33 provided in pairs for each section. A second flow rate adjusting means (for example, a valve) 31 is attached to the pipe and is configured to feed a desired amount of medium into the medium circulation path while adjusting the amount of medium sent out from the medium supply device 34. ing.

The above-mentioned pair of pipes 33 are arranged for each medium circulation passage 32 provided in each stage, and accordingly, the flow rate adjustment means 31 and the medium supply device 34 can also be provided in each stage. becomes. In another embodiment, by installing individual heat exchangers 30 for each stage of gas chambers, heating/cooling of each gas chamber can be more accurately controlled and the individual It is also possible to control the heat exchanger 30 over time by operating a timer. Here, when heating the gas chamber, it is also possible to flow the gas discharged from the furnace directly into the medium circulation passage while controlling it.

(Effects of the Invention) As is clear from the above description, the fluidized bed combustion apparatus of the present invention has dispersion holes for feeding gas into the fluidized bed in the combustion furnace in multiple stages at the bottom of the furnace wall of the combustion furnace. Further, a gas chamber is formed adjacent to the outside of the bottom of the furnace wall, the gas chamber being disposed substantially horizontally through the furnace wall and surrounding the outer opening of the distribution hole, so that the gas blown out from the distribution hole is formed adjacent to the outside of the bottom of the furnace wall. Since each stage is equipped with means for controlling it individually, it is possible to maintain a suitable fluidized state of the heat transfer medium particles without being affected by some clogging of the dispersion holes. It is possible to retain the ash, etc. that has been generated in the gas chamber and prevent the ash, etc. from flowing further upstream, and furthermore, it is possible to form a fluidized state of any heat transfer medium particles in the fluidized bed. It has excellent effects such as:

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the fluidized bed combustion apparatus of the present invention, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Figs. 3 to 5 are sectional views of the combustion apparatus of the present invention. Figures 6 to 13 are sectional views showing other embodiments of the combustion apparatus of the present invention. 10... Combustion furnace 10a... Furnace wall 12... Heat carrier particles 13... Fluidized bed 18... Dispersion hole 19... Gas chamber 20... Gas supply device 25... Flow rate adjustment Valve 31...Second flow rate adjustment means A...Heat exchange means Fig. 6 Fig. 7/'/ Fig. 8 Fig. 9 Fig. 11 Fig. 13

Claims (1)

[Claims] 1. Dispersion holes for feeding gas into the fluidized bed in the combustion furnace are provided in multiple stages at the bottom of the furnace wall of the combustion furnace, and are arranged to penetrate the furnace wall substantially horizontally. and a gas chamber surrounding the outer opening of the dispersion hole is formed adjacent to the outside of the bottom of the furnace wall, and means is provided for individually controlling the gas blown out from the dispersion hole for each stage. Characteristic fluidized bed combustion equipment. 2. The combustion apparatus according to claim 1, characterized in that the gas chamber is divided into sections for each stage, and a flow rate adjustment means is provided for adjusting the temperature, pressure, and amount of gas supplied to each section. Fluidized bed combustion equipment. 3. The fluidized bed combustion apparatus according to claim 2, wherein the flow rate adjustment means is constituted by a flow rate adjustment valve. 4. The combustion apparatus according to claim 2, wherein a heat exchange means for controlling the gas temperature in the gas chamber is disposed, and a second flow rate adjustment means for adjusting the flow rate of the heat medium flowing within the heat exchange means. . A fluidized bed combustion apparatus, characterized in that the temperature of the gas passing through each of the sections can be individually adjusted by being provided corresponding to each of the sections.