JPH0645168Y2 - Fluid bed heat recovery equipment - Google Patents

Description

[Detailed Description of the Invention] [Industrial application] The present invention creates a moving bed region of a fluidized heat medium in a fluidized bed furnace, and installs a heat exchanger in this part to recover the heat of the fluidized bed. It relates to the device.

[Conventional technology]

Conventionally, the following method has been used as a heat recovery method from a fluidized bed incinerator.

(1) A method in which a heat transfer tube is provided in a portion where the combustion exhaust gas flows, and a water heater is used for a small furnace and a waste heat boiler is used for a large furnace. When the heat transfer tube is provided on the upstream side of the exhaust gas cooling section, the heat transfer tube may be provided on the downstream side of the exhaust gas cooling section.

(2) A fluidized bed boiler system in which a heat transfer tube is provided in a fluidized bed having a fluidized medium to recover heat.

[Problems to be solved by the device]

However, in the method of (1), in which the heat transfer tube is provided on the upstream side of the exhaust gas cooling unit, the heat transfer tube is worn by the fine powdery fluid medium contained in the exhaust gas, and the corrosive gas (HCl gas in the exhaust gas , SOx gas, CO gas, etc.) corrode the heat transfer tube, while the method in which a heat transfer tube is provided on the downstream side of the exhaust gas cooling unit, corrosive gases (HCl gas, SOx gas,
There is an inconvenience that the heat transfer tube is corroded by CO gas).

Further, in the method (2), since the heat transfer tube comes into contact with the heat medium in a fluid state, the heat transfer tube is greatly worn and the durability deteriorates. In particular, a fluidized bed for waste incineration uses silica sand, which has a high abrasion property, as a fluidized medium. Therefore, a structure in which a heat transfer tube is simply provided in the fluidized bed causes a large amount of wear and cannot be realized as an apparatus.

On the other hand, recently, the proportion of high-calorie waste such as plastic, paper and wood chips in the waste has been increasing year by year, and the temperature in the fluidized bed is inevitably rising. When the temperature of the fluidizing medium rises by 100 to 150 ° C from the proper temperature range of 650 to 800 ° C, the low melting point substance adheres to the surface of the silica sand, causing a problem with flow inhibition. Therefore, the fluidized bed must be cooled by water spraying or the like, which is not preferable in terms of thermal economy.

The present invention has been made in view of the above points, and a moving bed region having a low flow velocity is provided on the side of the fluidized medium conduit or the fluidized bed from the fluidized bed, and a heat transfer tube is inserted into this moving bed region to move the moving bed. By forming the type heat exchange part, it is possible to effectively use and recover the amount of heat possessed by the high-temperature fluid medium in the furnace without cooling the fluidized bed with water spray, etc. It is an object of the present invention to provide a fluidized bed heat recovery device with less wear.

[Means for Solving the Problems]

In order to achieve the above object, the heat recovery device for a fluidized bed of the present invention has a fluidized bed 12 above the air distribution plate 10 and a wind box below the air distribution plate 10 as shown in FIG. With 14, fluidized bed
In a fluidized bed furnace in which the bottom of 12 and the incombustibles discharge device 16 are connected via an incombustibles discharge pipe 18, the sides of the fluidized bed 12 and the incombustibles discharge device 16 are connected to the fluid medium conduit 20.
And a moving bed region 22 having a diameter larger than that of the fluidizing medium conduit 20 is provided in the middle of this fluidizing medium conduit 20, and a heat transfer pipe 24 is inserted into this moving bed region 22 to move the fluidizing medium by furnace pressure. It is characterized in that a moving bed type heat exchange section 26 for moving is formed.

In addition, another heat recovery device for a fluidized bed according to the present invention is, as shown in FIGS.
In a fluidized bed furnace having a wind box 14 below the air dispersion plate 10 and the bottom of the fluidized bed 12 and an incombustibles discharge device 16 are connected via an incombustibles discharge pipe 18 to the side of the fluidized bed 12. A moving bed region 22a protruding from the furnace body is provided in the section, and a heat transfer tube 24a is inserted into the moving bed region 22a to move the fluidized medium by the furnace pressure.
a, the moving bed type heat exchange section 26a and the incombustibles discharging device.
16 is connected via a fluid medium conduit 40.

[Action]

In FIG. 1, the incombustible material in the fluidized bed 12 moves to the lower part of the fluidized bed 12, passes through the incombustible material discharge pipe 18, and falls into the incombustible material discharge device 16.

In the moving bed region 22, the heat medium is not in a flowing state but in a moving state, so that heat can be transferred without abrading the heat transfer tubes 24. Further, since the combustion exhaust gas is very rare and hardly exists in the moving bed region 22, the heat transfer tube is not corroded.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. However, the shape of the components described in this embodiment, the relative arrangement, etc., are not intended to limit the scope of the present invention to only those unless otherwise specified, and are merely examples of explanation. Only.

Example 1 FIG. 1 shows a case where a moving bed region is provided in the middle of a fluidized medium conduit in the single fluidized medium discharge system.

The incombustibles in the fluidized bed 12 move to the lower part of the fluidized bed 12, pass through the incombustibles discharge pipe 18, and fall into the incombustibles discharge device 16.

On the other hand, due to the pressure difference between the inside of the fluidized bed 12 and the inside of the incombustible material discharge device 16, the fluidized medium passes through the fluidized medium conduit 20 and the incombustible material discharge device.
Drop into 16 The pressure in the fluidized bed 12 near the inlet of the fluidized medium conduit is 900 to 1200 mmAq, and the pressure in the incombustibles discharger is about 0 mmAq.

In the middle of the fluidized medium conduit 20, a moving bed region 22 having a wide diameter and a sufficiently large cross-sectional area is provided. The heat medium introduced into the moving bed region 22 has a slow moving speed and forms a moving bed. Then, the high-temperature heat medium in the moving layer region 22 contacts the heat transfer tube 24 to apply heat, and then drops into the incombustible substance discharging device 16. By driving the incombustible discharge device 16, the fluid medium in the fluidized bed 12 is continuously discharged through the incombustible discharge pipe 18 and the fluid medium conduit 20.

The incombustibles and the heat medium from the incombustibles discharge device 16 are guided to a classifying device 28 such as a vibrating sieve and classified into an incombustibles and a heat medium, and the incombustibles are discharged to an incombustibles bunker (not shown) or the like. ,
The heat medium is circulated to the fluidized bed furnace via the heat medium circulation line 30.

10 is an air dispersion plate, 14 is a wind box, 26 is a moving bed type heat exchange section, 32
Is an exhaust gas outlet, 34 is an air inlet, and 36 is an inlet gate.

Example 2 FIGS. 2 and 3 show a case where a plurality of moving bed type heat exchange sections are provided on the side of the fluidized bed furnace body in the central discharge pipe system. In addition, it is also possible to provide the moving bed type heat exchange section in a circular shape on the side portion of the furnace body.

The incombustibles in the fluidized bed 12 move to the lower part of the fluidized bed 12, pass through the incombustibles discharge pipe 18, and fall into the incombustibles discharge device 16.

On the other hand, due to the pressure difference between the fluidized bed 12 and the incombustibles discharge difference 16, the fluidized medium passes through the fluidized medium conduit 40 and the incombustibles discharge device.
Drop into 16 The pressure at the height of the fluidized medium inlet in the fluidized bed 12 is 900 to 1200 mmAq, and the pressure in the incombustibles discharge device is about 0 mmAq.

The cross-sectional area of the moving bed zone 22a is configured to be sufficiently larger than the cross-sectional area of the fluidized medium conduit 40, so that the heat medium flowing from the fluidized bed 12 into the moving bed zone 22a forms a moving bed. . Then, the high-temperature heat medium in the moving layer region 22a comes into contact with the heat transfer tube 24a to give heat, and then falls into the incombustible substance discharging device 16.

L in FIG. 3 is a tube interval between the furnace body and the heat transfer tube, which is necessary to prevent wear of the heat transfer tube.

[Effect of device]

Since the present invention is configured as described above, it has the following effects.

(1) Since the heat transfer tubes are provided not in the fluidized bed but in the moving bed region where the flow velocity is extremely low, wear of the heat transfer tubes is extremely small and the service life is extended.

(2) Since it is not the conventional cooling in the fluidized bed by water injection, it is possible to effectively use the heat quantity possessed by the high-temperature heat medium, and moreover, the exhaust gas quantity is reduced, and the exhaust gas treatment facility,
The ventilation equipment can be made compact.

(3) In the lower part of the fluidized bed, oxygen rich, HCl
Since there is almost no corrosive gas such as gas, SOx gas and CO gas, the service life of the heat transfer tube is extended.

(4) Compared with the heat exchange with the exhaust gas, the heat transfer efficiency with the heat medium is high, and the device can be made compact accordingly.

(5) Since the method recovers heat by moving the flowing medium utilizing the pressure difference acting on the flowing medium, there is no drive unit,
It can be a simple mechanism.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a heat recovery device for a fluidized bed of the present invention, FIG. 2 is an explanatory view showing another embodiment of the device of the present invention, and FIG. 3 is a moving bed in FIG. It is an expansion explanatory view showing an example of a type heat exchange part. 10 ... Air dispersion plate, 12 ... Fluidized bed, 14 ... Wind box, 16 ... Incombustibles discharge device, 18 ... Incombustibles discharge pipe, 20 ... Fluid medium conduit, 22, 22
a ... moving bed area, 24, 24a ... heat transfer tube, 26,26a ... moving bed heat exchange section, 28 ... classifying device, 30 ... heat medium circulating line, 32 ... exhaust gas outlet, 34 ... air inlet, 36 ... inlet gate , 40 ... Fluid medium conduit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Tatsuyuki Shimokawa 2-5-25 Tenjinbashi, Kita-ku, Osaka-shi, Osaka Prefecture Kawasaki Heavy Industries, Ltd. Osaka Design Office (56) Reference JP-A-63-315801 (JP, A) JP-A-63-187001 (JP, A)

Claims (2)

[Scope of utility model registration request] 1. A fluidized bed (12) above the air dispersion plate (10).
Has a wind box (14) below the air dispersion plate (10), and the bottom of the fluidized bed (12) and the incombustibles discharge device (16) were connected via an incombustibles discharge pipe (18). In a fluidized bed furnace, the sides of the fluidized bed (12) and the incombustibles discharge device (16) are connected via a fluidized medium conduit (20), and this fluidized medium conduit (20)
In the middle of, the moving bed area (2
2) is installed, and heat transfer tubes (2
A fluidized bed heat recovery device, characterized in that a moving bed type heat exchange section (26) for inserting a fluidized medium by means of the pressure inside the furnace is formed. 2. A fluidized bed (12) above the air dispersion plate (10).
Has a wind box (14) below the air dispersion plate (10), and the bottom of the fluidized bed (12) and the incombustibles discharge device (16) were connected via an incombustibles discharge pipe (18). In a fluidized bed furnace, a moving bed area (22
a) is provided, and a heat transfer pipe (24a) is inserted into this moving bed region (22a) to form a moving bed heat exchange section (26a) that moves the fluidized medium by the internal pressure of the furnace. A heat recovery device for a fluidized bed, wherein the part (26a) and the incombustibles discharge device (16) are connected via a fluid medium conduit (40).