JPH01169213A - Fluidized bed combustion furnace - Google Patents

Abstract

PURPOSE:To ease the manufacture of a bottom plate and an air nozzle of a fluidized bed combustion furnace bottom part, and prevent poor fluidization from being generated in the case where an incinerator becomes large-sized by making the air nozzle perpendicular to horizontal furnace body bottom plate and lowering the height thereof gradually as it is approached to a foreign matter taking-out pipe. CONSTITUTION:An insulating plate 9 is provided in the circumferential wall of a fluidized bed part, an furnace body bottom plate 6 is horizontally placed on the bottom part of the furnace body 1, air nozzles 3 are perpendicular to a furnace body bottom plate 6, stepwise set in order of height changing so that the height of the nozzles 3 nearest to a foreign matter taking-out pipe 5 is lowest and a fixed bed 7 is formed on the lower part of air exhaust nozzles 8 of the nozzles 3. During operation a fluidized bed 2 is formed on the upper part of the air exhaust nozzles 8 and the fixed bed 7 toward the taking-out pipe 5 is formed inclined on the lower part thereof. Fuel 11 in which non-combustible material is mixed is supplied in preheated fluidized bed, combustible components are burned and combustion gas 12 is exhausted outside. On the other hand non-combustible material mixed in the fuel is deposited in the fluidized bed, moved along the fixed bed 7 inclined toward the taking-out pipe 5 and easily taken out from the taking-out pipe 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fluidized bed combustion furnace, and more particularly to a fluidized bed combustion furnace from which non-flammable foreign matter mixed in fuel can be easily extracted.

[Conventional technology] In recent years, in addition to coal and oil coke, low-quality materials such as garbage and industrial waste have been burned in fluidized beds, and non-flammable foreign materials such as iron scraps have been mixed in with these materials. There are many cases. These non-flammable foreign substances deteriorate the fluidization state and make it difficult to continue stable combustion, so they must be periodically or continuously extracted from the bed.

FIG. 3 is a partial sectional view of a fluidized bed combustion furnace according to the prior art. This device consists of a fluidized bed 2 in a furnace 1, a foreign matter extraction pipe 5 provided at the center of the bottom of the furnace 1, and a conical or square pyramid-shaped foreign material extraction pipe 5 provided at an angle toward the foreign material extraction pipe 5. A fluidized bed furnace bottom plate 6, an air nozzle 3 provided vertically upward on the fluidized bed furnace bottom plate 6, an air outlet 8 provided at the tip of the air nozzle, a fluidized bed peripheral wall, and a fluidized bed furnace bottom plate 6.
It has a heat insulating material 9 provided at the top and a wind box 4.

The insulation 9 is provided to minimize heat loss when burning low quality fuel. In such a configuration, the fluidizing air IO is supplied from the wind box 4 through the fluidized bed furnace bottom plate 6 and the air nozzle 3 into the fluidized bed 2 from the air outlet 8. The non-flammable foreign matter is mixed with the fuel and supplied from the furnace side wall or the furnace top (not shown) above the fluidized bed, falls into the fluidized bed, and is deposited on the fluidized bed furnace bottom plate 6. On this occasion,
The non-flammable foreign matter moves to the foreign matter extraction pipe 5 at the lowest part of the furnace 1 by the slope of the fluidized bed furnace bottom plate 6, and is discharged together with the fluidized medium.

Non-flammable foreign matter moves along the inclined fluidized bed bottom plate 6, so the larger the inclination angle of the fluidized bed bottom plate 6, the easier it is to move. There is a problem in that the height difference becomes large and the fluidized air concentrates on the peripheral wall portion where the layer height is low, causing poor fluidization.

In addition, the air nozzle 3 needs to be installed vertically upward on the inclined fluidized bed furnace bottom plate 6, which makes it difficult to manufacture.Furthermore, since low-quality fuel is burned, it is necessary to put a heat insulating material on the bottom of the fluidized bed furnace, which increases the processing time. The disadvantage is that there are many

(Problems to be Solved by the Invention) An object of the present invention is to solve the above-mentioned problems of the prior art, to make it easy to manufacture the bottom plate and air nozzle at the bottom of the fluidized bed furnace, and to ensure that even when the furnace is enlarged, there is no fluid flow. An object of the present invention is to provide a fluidized bed combustion furnace that does not cause oxidation failure.

[Means for Solving the Problems] The present invention provides a fluidized bed combustion furnace having a plurality of air nozzles provided on the bottom plate of the furnace body and a foreign matter extraction pipe, wherein the bottom plate of the furnace body is horizontal, and the bottom plate of the furnace body is horizontal. The air nozzle is installed perpendicularly to the bottom plate of the furnace main body, and the height of the air nozzle decreases as it approaches the foreign matter extraction pipe.

[Function] Adjust the height of the air outlet of the fluidizing air to be closer to the foreign matter extraction pipe (
By gradually lowering the air outlet, active flow of the fluid medium occurs at the upper part of the air outlet, while no flow of the fluid medium occurs at the lower part of the air outlet, resulting in a fixed bed (flow stop layer).
is formed. Since the fixed layer forms an inclination along the air outlet, the non-flammable foreign matter moves along the inclination of the fixed layer and is extracted from the foreign matter extraction pipe located at the bottom.

The fixed layer usually has very poor heat transfer and serves as a heat insulating material, so the conventional heat insulating material in the bottom plate of the furnace body can be omitted. In addition, since the bottom plate of the furnace body is horizontal, it is easy to manufacture, and the air nozzle only needs to be installed perpendicularly to the bottom plate of the furnace body, making the installation process easy and greatly reducing the number of processing steps and work hours. be able to. Further, by combining a bottom plate in which the air jet ports of the air nozzles are arranged in, for example, a quadrangular pyramid shape toward the foreign matter extraction port, it becomes possible to easily increase the size of the furnace. That is, even if the furnace is enlarged, the difference in layer height between the center and the peripheral wall of the furnace can be made small, so that fluidization failure due to uneven flow of fluidization air, as seen in the prior art, does not occur.

〔Example] Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 1 is a sectional view of a fluidized bed combustion furnace showing one embodiment of the present invention. The difference between this figure and FIG. 3 is that a heat insulating material 9 is provided only on the peripheral wall of the flow surface, a bottom plate 6 of the furnace body without any heat insulating material is provided horizontally at the bottom of the furnace body 1, and an air nozzle 3 is attached to the bottom plate 6 of the furnace body 1. The air nozzles 3 are installed vertically and in a stepwise manner, with the heights being changed in order so that the height of the air nozzle 3 closest to the foreign matter extraction pipe 5 is the lowest, and the air jet ports 8 of the air nozzles 3 provided in the stepwise manner are installed in a stepwise manner. The fixed layer 7 is formed below the .

The air nozzle 3 is vertically attached to the upper part of the bottom plate 6 of the furnace main body, and the height of the air jet port 8 of the air nozzle 3 is lowered in a stepped manner toward the foreign matter extraction pipe 5, so that the air is not removed during operation. A fluidized bed 2 is formed at the L portion of the air jet port 8, and a fixed bed 7 is formed at the lower part of the air jet port 8 so as to be inclined toward the foreign matter extraction pipe 5.

The fuel 11 mixed with non-combustible foreign matter is supplied to a fluidized bed preheated to a temperature at which the fuel can be combusted by means such as a bed burner or a hot blast furnace (not shown), where the combustible components are combusted and the combustion gas 12 is released outside the furnace. It is discharged. On the other hand, the non-flammable foreign matter mixed in the fuel settles in the fluidized bed, moves along the fixed bed 7 inclined toward the foreign matter extraction pipe 5 provided on the bottom plate 6 of the furnace body, and moves to the foreign matter extraction pipe 5. easily extracted from. Fixed layer 7
The inclination angle of can be easily adjusted by changing the height of the air outlet 8 of the air nozzle 3.

The shape of the furnace body 1 used in the present invention may be circular or square. The fixed bed 7 is preferably formed of a stopped fluidized bed, but may be partially formed of a heat insulating material (refractory material) if desired.

FIG. 2 is a partial sectional view of a fluidized bed combustion furnace according to another embodiment of the present invention. This apparatus is a fluidized bed combustion furnace in which several small rectangular furnace main body bottom plates 6 shown in FIG. 1 are combined at the bottom of the furnace main body. According to this embodiment, even if the furnace becomes large-sized, fluidization failure due to uneven flow of fluidization air will not occur.

〔Effect of the invention〕

According to the present invention, since non-flammable foreign matter in the fluidized bed can be smoothly extracted, stable combustion can be continued,
Further, the fluidized bed combustion furnace is easy to process and manufacture, and the device can be made larger.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a fluidized bed combustion furnace according to an embodiment of the present invention, FIG. 2 is a partial sectional view of a fluidized bed combustion furnace according to an embodiment of the present invention, and FIG. 3 is a fluidized bed combustion furnace according to the prior art. FIG. 2 is a partial cross-sectional view of a bed combustion furnace. 1... Furnace body, 2... Fluidized bed, 3... Air nozzle, 4... Wind box, 5... Foreign matter extraction pipe, 6... Furnace main body bottom plate, 7... Fixed Layer, 8...Air outlet, 9...
Heat insulating material, 10... Fluidizing air, 11... Fuel, 12
...Combustion gas. Agent Patent Attorney Takeshi Kawakita

Claims (1)

[Claims] (1) In a fluidized bed combustion furnace having a plurality of air nozzles provided on the bottom plate of the furnace body and a foreign matter extraction pipe, the bottom plate of the furnace body is horizontal, and the air nozzles are perpendicular to the bottom plate of the furnace body. A fluidized bed combustion furnace characterized in that the furnace is installed such that its height gradually decreases as it approaches the foreign matter extraction pipe.