JPS60152810A - Fluidized bed furnace for burning combustibles in sewage mud - Google Patents

Abstract

PURPOSE:To improve an efficiency of drying and improve an efficiency of incineration as much as possible by a method wherein a screw conveyor for agitating combustibles toward the upstream side of discharged gas while being moved is arranged on a drying shelf. CONSTITUTION:A free board 6 through which discharged gas generated from a fluidized bed 2 ascends is formed above the fluidized bed forming part 3. Upper and lower two stages of drying shelves 7 are arranged inside the free board 6. The upper drying shelf 7a is provided with a screw conveyor 16 for transporting the combustibles to be fed to the shelf from the transporting end 11 to the injecting end 12 while being rotated. Similarly, the lower drying shelf 7b is provided with a screw conveyor 17 to transport the combustibles transported from the upper drying shelf 7a through the opening 10 to the opening 13. The combustibles are sufficiently agitated and rotated at each of the drying shelves 7a, 7b toward the upstream side of the discharging gas, so that a rate of contact between the combustibles and the discharging gas is improved and the combustibles are sufficiently dried.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a fluidized bed furnace for incinerating materials to be incinerated such as sewage sludge. The present invention relates to a fluidized bed furnace for incinerating sewage sludge, which can increase the drying efficiency by expanding the contact surface between the waste gas discharged from the fluidized bed and the material to be incinerated.

[Technical background of the invention and its problems] In general, sewage sludge, etc. with a moisture content of 60 to 80% water is incinerated in a fluidized bed furnace, in which the material to be incinerated is incinerated while being fluidized by a fluidizing gas. A known method for incinerating materials is to dehydrate or dry the materials to be incinerated in advance, and then incinerate them in a fluidized bed furnace.

Conventionally, the moisture content of the incineration material is dried from 75% to 50% to 60% using a paddle type heat exchanger that exchanges heat with the exhaust gas discharged from the fluidized bed furnace. Incineration was being carried out at.

However, this method has the disadvantage that material handling such as transportation equipment for the dried incineration materials and uF gas duct piping equipment are complicated. It has been proposed to form a drying chamber and dry the materials to be incinerated by bringing them into direct contact with exhaust gas.

This will be specifically explained in detail according to FIG.

A freeboard C is formed above the inside of the fluidized bed furnace a to move the exhaust gas discharged through the fluidized bed upward. Inside this freeboard C, there are two drying shelves, upper and lower, d and e i.
fi, and a rotary scraper is provided on each drying shelf d, e. These rotary scrapers [are fluidized bed furnaces a]
It is taken up and down coaxially with the rotating shaft g hanging down from the top of the
=it) has been done.

In addition, the upper drying shelf d has a rotating shaft in its center.

A relatively large opening is provided through which the material to be incinerated is inserted and transferred to the drying rack 0 located at the lower stage.

On the other hand, the outer periphery of the lower drying rack 0 is connected to a fluidized bed furnace a in order to charge the materials to be incinerated into the fluidized bed located below the drying rack 0.
It has a predetermined gap between the inner walls i. In particular, the outer diameter of the lower drying rack e is set to be small in order to uniformly charge the materials to be incinerated into the fluidized bed.

Therefore, the material to be incinerated that is placed on the upper drying rack d comes into contact with the exhaust gas flowing from the opening, is dried, and is transferred from the opening to the first drying rack e by the scraper f.

The material to be incinerated is transferred to the lower stage and is further brought into contact with the exhaust gas and dried, after which it is charged into the fluidized bed.

By the way, the area of free board C (i) is limited, and flat drying shelves d and e are provided there, and each shelf d,
A scraper is installed on top of the e, which limits the area where the material to be incinerated comes into contact with the exhaust gas, making it unsuitable for effective drying.

In addition, there was a problem in that the materials to be incinerated loaded into the drying racks d and e could not be rotated effectively when being transferred by the scraper f depending on the scraper.

Furthermore, since the scrapers f are coaxially attached to the rotating shaft g, there is a problem in that a large load is applied to the bearing structure in the upper part of the furnace.

[Objective of the Invention J] The present invention has been devised to effectively solve the problems that conventionally occur when incinerating IJJ materials after drying them in a fluidized bed furnace.

The purpose of the present invention is to improve the incineration efficiency by increasing the drying efficiency of materials to be incinerated with a high moisture content, such as sewage sludge, by effectively bringing them into direct contact with the exhaust gas generated from the fluidized bed in the furnace. Incineration of one object such as sewage sludge that can be improved
The present invention provides a fluidized bed furnace for I.

[Summary of the Invention] In order to achieve the above object, the present invention forms a fluidized bed furnace in which the material to be incinerated is incinerated while fluidizing it together with a fluidized medium (for example, sand, etc.), and a fluidized bed furnace is formed above the fluidized bed. A drying rack is installed in the treeboard for drying the incinerated materials supplied by contact with the flow of exhaust gas discharged from the fluidized bed, and for charging the materials into the fluidized bed. The screw conveyor \7 is installed to stir and move the incinerated material in a countercurrent flow to the upstream side of the exhaust gas, and the screw conveyor 7 is installed to rotate the incineration material and transport it in a countercurrent flow to the exhaust gas, increasing the transfer distance to reduce the exhaust gas. It is designed to increase the rate of contact with

[Embodiments of the Invention] A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

As shown in Fig. 2, the fluidized bed furnace 1 has a fluidized bed forming section 3 at its bottom that forms a fluidized bed 2 for incinerating the material to be burnt while fluidizing it with fluidizing gas. . A wind box 4 for introducing perturbation gas is formed above the fluidized bed forming section 3, and is configured to supply the fluidization gas to the fluidized bed 2. A fluidized gas flow system 5 is connected to the wind box 4.

In addition, the fluidized bed forming section 3 is filled with a fluidized medium such as sand (
The gas is fluidized by the fluidized gas supplied from the wind box 4, and while the material to be incinerated charged therein is fluidized, the material to be incinerated is incinerated.
-4.

A free board 6 is formed above the fluidized bed forming section 3, on which the v1 gas generated from the fluidized bed 2 rises.

Inside this freeboard 6, drying shelves 7 are installed in two levels, upper and lower.
Being beaten. The upper drying shelf 7a is provided on the negative side wall 8 and extends from the other side wall 9 to the other side wall 9, and has an opening 10 between the other side walls 9 to provide a predetermined gap. Therefore, in the upper drying rack 7a, the side wall 8 side forms the carry-in end 11, and the end forming the frontage 10 forms the carry-out end 12 of the incinerated material.
form. At the carry-in end 11, there is an input port 14 for materials to be incinerated.
is set up.

A lower drying shelf 7b is installed on the lower blade of the upper drying shelf 7a ().
It is being This lower drying shelf 7b is the same as the upper drying shelf 7b.
The base end is supported by the side wall 9, and the other end is extended to the side wall 8 so as to receive the materials to be incinerated from the unloading end 12 of a and transfer it to the side wall 8. With a predetermined gap between -
(See the L1 section 13 facing downward.

The upper drying rack 7a and the lower drying rack 7b are separated by a predetermined gap in the vertical direction from each other, and the frontage 10 of the lower drying rack 7b is
The exhaust gas is formed so that it moves upward within the freeboard 6 through the opening 10 in the upper stage.

An exhaust passage 15 is provided at the top of the furnace for exhausting exhaust gas from the freeboard 6 to the outside.

The upper drying rack 7a contains the burnt Ml that is put on this rack.
A screw conveyor 16 for rotating and transferring articles from the carry-in end 11 to the carry-out end 12 extends over the drying rack 7a in the longitudinal direction, as shown in the figure.

In addition, the lower drying rack 7b is also equipped with a screw container.
1717 is shown in stage 1]. This screw competition 1
Reference numeral 717 is for transporting the materials to be incinerated from the upper drying rack 7a through the opening 10 to the opening 13 where the materials to be incinerated are transferred.

A plurality of screw conveyors a'+6.17 provided on the upper and lower drying racks 7a and 7b are provided in parallel to the conveying direction as shown in FIG.
, 7b, the all-C incineration material is transferred while rotating.

The effects of the present invention will be described below.

The material to be incinerated such as sewage sludge with a high water content is first put into the upper drying rack 7a from the input port 14 as shown in FIG. However, at the same time as the fluidized bed 2
This means that the gas is transported countercurrently to the rising exhaust gas.

The material to be baked Nj that has reached the carry-out end 12 of the upper drying rack 7a is transferred downwardly to the lower drying rack 711 provided below the upper part 10 of the upper part 10.

The burnt material transferred to the lower drying rack 7b is further rotated by a screw conveyor X717 to form a discharge end.
The sample is transferred to the opening 13.

Dry on the bottom! 51 to the shelf 7b is similarly rotated by the squew conveyor 17 and transferred in countercurrent to the flow of exhaust gas.

In particular, the L1 materials to be burned are rotated in the drying racks 7a and 7b while being countercurrently flowed toward the upstream side of the exhaust gas, sufficiently stirred, and transferred, so that the contact rate with the exhaust gas increases and the materials are sufficiently dried. It turns out.

The thus dried material to be incinerated descends from the opening 13 of the lower drying shelf 7b into the fluidized bed 2 below it and is charged therein.

The materials to be incinerated are transferred on each of the drying shelves 7a and 7b while being rotated and stirred by the screw conveyors 16 and 17, increasing the direct contact rate with the exhaust gas, and at the same time, the screws and shelves are heated by the exhaust gas. Therefore, the heat transfer rate of the material to be incinerated is increased and the drying rate is improved.

In addition, as shown in Fig. 4, 716 goes to the screw competition.

In contrast to 17, if the drying rack 7 is formed into a curved surface so as not to follow the screw conveyor, the efficiency of conveying and stirring the material to be baked L1 will be greatly improved.

Further, although in the above embodiment the fluidizing gas is supplied to the fluidized bed forming section 3 through the wind box 4, the present invention can be similarly applied to a fluidized bed furnace using an aeration pipe.

[Effects of the Invention] As is clear from the above, the present invention exhibits the following excellent effects.

(1) In the drying rack, the material to be baked is stirred and moved in countercurrent to the exhaust gas, so that the contact time with the exhaust gas can be expanded as much as possible, and the drying efficiency can be increased as much as possible.

(2) Since sewage sludge and other incinerated substances with a high moisture content are sufficiently dried by the exhaust gas in the free board in the furnace, the incineration efficiency in the fluidized bed can be increased.

(3) Since the freeboard inside the furnace can be used effectively, the time spent in contact with the exhaust gas flow above the drying shelf is longer.
The material drying means can be made more compact.

[Brief explanation of drawings]

Figure 1 shows a conventional fluidized bed furnace -1'tl'J 12!
2 is a side rJJi side view showing an embodiment of the present invention, FIG. 3 is a sectional view taken along the line ■-■ in FIG. 2, and FIG. FIG. 3 is a partial cross-sectional view showing the relationship. In the figure, 2 is a fluidized bed, 6 is a free board, and 7a. 7b is a drying rack, and 16.17 is a screw rack A7. Figure 1 Figure 4 Figure 2 Figure 3 Figure 7 Procedure No. 11 Official Book (Method) May 9, 1980 Director General of the Patent Office Kazuo Wakasugi 1, Case Indication Patent Application No. 8618-1982, Name of the invention: Fluidized bed furnace 3 for incinerating sewage sludge to be incinerated; Relationship to the amended case Patent applicant (009) Ishikawajima Harima Heavy Industries Co., Ltd. 4; Agent postal code: 105 Atago, Minato-ku, Tokyo '1-6-78 Atagoyama Attorney Building 5 Date of amendment order April 24, 1980 (Date of dispatch) 6. Subject of amendment 1. Name of invention column) 7. Contents of amendment

Claims (1)

[Claims] A fluidized bed that incinerates the material to be incinerated while fluidizing it with a fluidizing gas, and a fluidized bed that is installed in a freeboard formed above the fluidized bed to incinerate the material to be incinerated by bringing it into contact with the JJI gas discharged from the fluidized bed. a drying rack for drying the 1- to-be-burned material and charging it into the fluidized bed;
A fluidized bed furnace for incinerating sewage sludge to be incinerated, characterized in that it is equipped with a screw for stirring and moving the material while causing it to flow countercurrently to the upstream side of the exhaust gas.