JPH09138076A - Fluid bed furnace sand transfer method - Google Patents

Abstract

(57) [Abstract] An air transportation system enables flexible arrangement of a means for transporting fluidized sand, reduces the installation area, and uses air as a transportation medium as a cooling medium. . SOLUTION: The fluidized sand S carried out from a fluidized bed furnace 1 is supplied to an air transportation path 18 through a sand receiving hopper 14, and the fluidized sand S is transported in the air transportation path 18 by using air supplied from a fluidized blower 10 as a transportation medium. In the middle of the air transportation path 18, the fluidized sand S and the coarse foreign matter K contained in the fluidized sand S are classified by the former cyclone 20, and the carrier medium and the fluidized sand S are classified by the latter cyclone 21, and the classified fluid is classified. The sand S is circulated and returned from the underflow port 24 of the rear cyclone 21 into the fluidized bed furnace 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transferring sand in a fluidized bed furnace into and out of the furnace, and relates to a method for transporting sand in a fluidized bed furnace using an air transportation system.

[0002]

2. Description of the Related Art Conventionally, in a fluidized bed furnace, combustion residues are discharged to the outside of the furnace together with fluidized sand as coarse foreign matters, and the coarse material is separated from the fluidized sand by classification in a sand sorter consisting of a vibrating screener. After that, the fluidized sand is conveyed to a sand hopper provided at the upper portion of the furnace by a sand circulating conveyor including a screw conveyor and a bucket conveyor, and is introduced into the furnace from the sand hopper.

[0003]

However, in the above-mentioned conventional structure, when the sand circulating conveyor is formed by the screw conveyor or the bucket conveyor, the screw conveyor or the bucket conveyor has only a structurally two-dimensional layout. This is not allowed, and the placement position of the sand circulation conveyor with respect to the fluidized bed furnace is fixedly defined, and the screw conveyor and bucket conveyor have screws and buckets inside the transport path, which increases the outer diameter dimension. When installing the bed furnace, it was necessary to secure not only the area occupied by the fluidized bed furnace itself but also a large area including the bucket conveyor as the installation area. In addition, a cooler for cooling the high temperature fluidized sand had to be provided separately from the bucket conveyor.

The present invention solves the above-mentioned problems, and by using an air transportation system, it is possible to flexibly arrange a means for transporting fluidized sand,
It is an object of the present invention to provide a method for transporting sand in a fluidized bed furnace in which the transporting means itself can perform a cooling function by reducing the installation area and using air as a transporting medium as a cooling medium.

[0005]

In order to solve the above-mentioned problems, a method for transporting sand in a fluidized bed furnace of the present invention is to supply fluidized sand discharged from a fluidized bed furnace to an air transportation path through a sand receiving hopper, The fluid sand is transported using the air supplied from the blower in the air transportation route as the transportation medium, and the fluid cyclone and the coarse foreign matter contained in the fluid sand are classified in the middle of the air transportation channel, and the transportation medium in the latter cyclone. And the fluidized sand are classified, and the classified fluidized sand is circulated and returned into the fluidized bed furnace from the underflow port of the subsequent cyclone.

Further, in a fluidized bed furnace in which fluidized air is supplied to a sand layer from a fluidized blower through a ventilation passage communicating with a discharge port and fluidized sand is fluidized by the fluidized air, a discharge side first switching damper interposed in the ventilation passage is provided. While closing, the discharge side second switching damper provided on the air transport path branched from the air blow path on the flow blower side of the discharge side first switching damper is opened, and is connected to the intake path communicating with the suction port of the flow blower. The suction-side second switching damper that closes the installed suction-side first switching damper and that is interposed in the air transportation path from the overflow port of the subsequent cyclone that joins the intake passage on the flow blower side from the suction-side first switching damper And the air blown from the flow blower is supplied to the air transportation path as a carrier medium.

With the above-mentioned structure, since the coarse foreign matter is classified from the fluidized sand by the cyclone on the way of the air transportation route for returning the fluidized sand to the fluidized bed furnace, a separate vibrating screener or the like is used for separating the coarse foreign matter. The sand sorter which requires the power of is unnecessary, the energy of the air of the carrier medium can be utilized for the separating action, and the energy can be saved. Further, since the fluidized sand is transported by using air as a carrier medium, there is no mechanical element in the pipe forming the air transportation path. Therefore, the diameter of the air transportation path is smaller than that of a screw conveyor, a bucket conveyor, or the like, and the air transportation path can be bent in any direction and can be flexibly arranged three-dimensionally, so that the installation area can be reduced. . In addition, since the air of the ambient temperature, which is the carrier medium, cools the fluidized sand during transportation, it is not necessary to provide a separate cooling means, and the carrier means itself can perform the cooling function.

Since the flow blower has a sufficient capacity for air transportation in terms of both air volume and pressure, the air blown from the fluid blower is changed in the air transportation path by operating each switching damper to change the air blowing route. It can be used as a carrier medium, and it is not necessary to separately provide power for pneumatic transportation of fluidized sand.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a fluidized bed furnace 1 has a sand layer (not shown) formed by fluidized sand S inside,
The top part communicates with the flue 2, and the upper part has a sand input port 3 for inputting the fluidized sand S and a combustion material input port 4 for inputting the dehydrated cake to be incinerated.

The fluidized bed furnace 1 has a sand discharge port 5 for the fluidized sand S on the lower side thereof, a hot air stove 7 is provided in communication with a wind box 6 at the bottom of the furnace, and a burner 8 is provided in the hot air stove 7. In addition to that, the air passage 9 is connected. The blower passage 9 has a base end side communicating with the discharge port of the flow blower 10, and a discharge side first switching damper 11 is provided near the discharge port, and waste heat of exhaust gas from the flue 2 is used on the way. An exhaust gas air preheater (not shown) is installed. An intake passage 12 is connected to the inlet of the flow blower 10, and a suction side first switching damper 13 is interposed in the intake passage 12.

The sand discharge port 5 communicates with a sand receiving hopper 14, and the sand receiving hopper 14 has a sand replenishing port 15 at its upper portion.
The lower chute 16 communicates with the outward path of the air transportation path 18 via a rotary valve 17. Air transport path 18
Is branched from the blower passage 9 on the side of the flow blower 10 from the first discharge side switching damper 11 on the starting side, and the second switching damper 19 on the discharging side and a pre-stage cyclone 20 for classifying coarse foreign matters K such as combustion residues in the middle. The latter stage cyclone 21 for classifying the fluidized sand S is interposed. The underflow port 22 of the former cyclone 20 is communicated with the hopper 23, and the underflow port 24 of the latter cyclone 21 is the rotary valve 2
5 and the input switching damper 26, and the sand input port 3 and the discharge switching damper 27 to the outside of the system. Overflow port 28 of rear cyclone 21
Joins the intake passage 12 on the side of the flow blower 10 from the suction side first switching damper 13 via the return path of the air transportation path 18, and the suction side second switching damper 29 is interposed in the air transportation path 18. is there.

The operation of the above structure will be described below. With the discharge-side first switching damper 11 and the suction-side first switching damper 13 of the blower passage 9 opened, the ambient temperature air (supplied from the odor system or the like) sucked from the intake passage 12 is used as the flowing air to preheat the air by the flow blower 10. The hot air supplied from the burner 8 is added to the preheated flowing air supplied from the blower 9 through the air conditioner (not shown), and the flowing air adjusted to an appropriate temperature is supplied to the wind box 6. In a state in which the fluidized air flowing into the wind box 6 fluidizes and heats the fluidized sand S of the sand layer, the dehydrated cake introduced into the furnace from the combustion material inlet 4 is taken into the fluidized sand S and burned.

When the coarse impurities K such as combustion residues are discharged to the outside of the furnace, the sand discharge damper 5a provided in the sand discharge port 5 is opened, and the sand receiving hopper 14 from the sand discharge port 5 together with the fluidized sand S is opened.
To take out. Further, when the total amount of the fluidized sand S circulating inside and outside the furnace is insufficient, the fluidized sand S is replenished to the sand receiving hopper 14 from the sand replenishing port 15.

When circulating the fluidized sand S stored in the sand receiving hopper 14 into the furnace and separating the coarse impurities K,
The discharge side first switching damper 11 and the suction side first switching damper 13 are closed, the discharge side second switching damper 19 and the suction side second switching damper 29 are opened, and the air blown by the flow blower 10 is used as a carrier medium. Supply to the air transportation path 18,
By opening the rotary valve 17, the fluidized sand S carried out from the fluidized bed furnace 1 is supplied to the air transportation path 18 through the sand receiving hopper 14.

In the air transport path 18, the flow blower 1
The fluidized sand S is transported using air supplied from 0 as a transport medium, the fluidized sand S and the coarse impurities K contained in the fluidized sand S are classified by the pre-stage cyclone 20, and the latter cyclone 21 fluidizes with the air of the transport medium. Classify with sand S. Pre-stage cyclone 2
The coarse foreign matter K separated at 0 falls from the underflow port 22 of the preceding cyclone 20 into the hopper 23. on the other hand,
The fluidized sand S separated by the rear cyclone 21 is opened in the fluidized bed furnace from the underflow port 24 of the rear cyclone 21 while the rotary valve 25 is opened, the input switching damper 26 is opened, and the discharge switching damper 27 is closed. Circulate to. When taking out the fluidized sand S, the closing switching damper 26 is closed and the discharging switching damper 27 is opened.

[0016]

As described above, according to the present invention, the energy contained in the air of the carrier medium on the way of the air transportation path is used to classify the coarse impurities from the fluidized sand by the cyclone. This eliminates the need for a sand sorter that requires separate power, and can save energy. Since the air transportation path can be flexibly arranged in a three-dimensional manner by bending in any direction, the installation area can be reduced. Since the air of the ambient temperature, which is the carrier medium, cools the fluidized sand during transportation, it is not necessary to separately provide a cooling means, and the carrier means itself can perform the cooling function.

Further, the air blown from the fluidized blower can be used as a carrier medium in the air transportation path, and it is not necessary to separately provide a power for pneumatically transporting the fluidized sand.

[Brief description of the drawings]

FIG. 1 is a schematic view of a fluidized bed furnace showing an embodiment of the present invention.

[Explanation of symbols]

 1 Fluidized Bed Furnace 3 Sand Inlet 5 Sand Exhaust 9 Air Blower 10 Fluid Blower 11 Discharge Side First Switching Damper 12 Intake Path 13 Suction Side First Switching Damper 13 14 Sand Receiving Hopper 18 Air Transport Path 19 Discharge Side Second Switching Damper 20 Pre-stage cyclone 21 Post-stage cyclone 29 Suction side second switching damper

Claims (2)

[Claims] 1. The fluidized sand discharged from a fluidized bed furnace is supplied to an air transport path through a sand receiving hopper, and the fluid sand is transported by using air supplied from a blower in the air transport path as a carrier medium, and in the middle of the air transport path. Fluidized sand and coarse impurities contained in fluidized sand are classified by the first-stage cyclone, the carrier medium and fluidized sand are classified by the second-stage cyclone, and the classified fluidized sand is introduced into the fluidized-bed furnace from the underflow port of the second-stage cyclone. A method for transporting sand in a fluidized bed furnace, which is characterized in that it is circulated and returned. 2. In a fluidized bed furnace, in which fluidized air is supplied to a sand layer from a fluidized blower through an air passage communicating with a discharge port, and fluidized sand is caused to flow by the fluidized air, a discharge side first switching damper interposed in the air passage is provided. While closing, the second discharge side switching damper is opened on the air transportation path branched from the air blow path on the flow blower side of the first discharging side switching damper,
The air from the overflow port of the subsequent cyclone that closes the suction-side first switching damper that is interposed in the intake passage that communicates with the suction port of the flow blower and that merges with the suction passage on the flow blower side from the suction-side first switching damper 2. The sand conveying method for a fluidized bed furnace according to claim 1, wherein the suction side second switching damper provided in the transportation path is opened to supply the air blown from the fluid blower to the air transportation path as a transportation medium.