JPH07233915A - High speed circulation type fluidized bed incinerator - Google Patents

Abstract

PURPOSE:To efficiently self-burn to incinerate municipal refuse containing much volatile components and low quantity of generation heat. CONSTITUTION:A high speed circulation type fluidized bed incinerator diffuses up a layer material FG via a second bed FB for burning material to be incinerated from a dry preheating first bed SB and circulates it to the bed SB side by circulating it about an upper end of a lower partition wall 22. A guide partition wall 23 is formed by extending upward from the upper end of the wall 22, a vertical guide wall 25 is suspended along the wall 23 from a roundabout guide wall 24 disposed above the wall 23, gas roundabout passages 26 is formed at both sides of the wall 23, and a falling sand tube 27 for circulating the material FG from an inlet of an exhaust gas passage 12 to the vicinity of an outlet of a chute 3 of the material to be incinerated is provided through the wall 25 across the passage 26 from an upper part of the wall 22. Accordingly, volatile components can be sufficiently burned in the state that almost no layer material exists in the gas roundabout passage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed circulation type fluidized bed refuse incinerator for incinerating a material to be incinerated by circulating a layer material at a high speed inside.

[0002]

2. Description of the Related Art In recent years, incinerators that incinerate municipal solid waste are generally widely spread by using a stoker, but due to the strengthening of carbon monoxide and dioxin emission regulations, a fluidized bed furnace is used. Incineration methods are becoming popular.
For example, a high-speed circulating fluidized bed incinerator that circulates layered material in the vertical direction was developed for the purpose of incinerating industrial waste such as wood chips, bark, and waste tires. , The hearth load is 3 ~ that of a general fluidized bed furnace
It is as high as 5 times, and because the internal circulation layer material covers the incineration object, harmful volatiles generated from the incineration object are not blown upward before combustion, which results in carbon monoxide and nitrogen. It can be said that it is a low pollution type incinerator that can suppress the generation of oxides, dioxins, etc., and can be made extremely compact compared to other types of incinerators currently in operation.

This high-speed circulation type fluidized bed incinerator proposed in FIG. 4 of JP-A-64-46511, for example, has a vertical partition wall 2 in the lower part of the furnace body 1 as shown in FIG.
Above the first bed SB and the first bed (low-speed bed) SB for mixing and drying the material to be burned supplied from the chute 3 provided on the front outer wall 1a with the layered material FG for drying and pyrolysis. Pyrolysis zone 4 for burning volatile components at
And the air to be incinerated sent from the low speed bed 4 by the transfer air nozzle 5 is blown up above the first bed FB by the air blown from the second bed (high speed bed) FB and the high speed combustion air nozzle 6. To form a main combustion zone 7 in which mixed combustion is performed, and the rear outer wall 1 of the furnace body 1
The material to be burned and the layer material F are blown up by the guide wall 8 that projects from the b and covers the main combustion zone 7 and the partition 2 above.
Combustion gas from the post-combustion zone 9 formed between the post-combustion zone 9 in which G is further mixed and combusted, and the guide wall 8 and the table 9a projecting to the first bed SB side above the partition wall 2 and The circulation passage 10 for dropping the layer material FG onto the incineration material in the vicinity of the outlet of the supply chute 3 and sending the combustion exhaust gas to the secondary combustion chamber 11 above the furnace body 1 via the exhaust gas passage 13 in the front part of the guide wall 8. It is equipped with and. Reference numeral 12 is an ash outlet provided at the bottom of the furnace body 1.

[0004]

FIG. 5 and FIG. 5 show the temperature, air, exhaust gas composition, etc. at each part of the experimental results of incineration of wood chips and municipal solid waste by the high-speed circulating fluidized bed incinerator having the above-mentioned configuration. 6 respectively.

Although the wood chips shown in FIG. 5 show a good combustion state, the burning of municipal solid waste shown in FIG. 6 requires the auxiliary combustion of kerosene, and when the auxiliary combustion of kerosene disappears, the thermal decomposition zone 4 and the main combustion. The temperature of the zone 7 decreases, and conversely the secondary combustion chamber 1
The temperature of No. 1 tended to increase, and eventually it became impossible to self-combust.

The reasons why municipal waste does not self-combust (1) Even if the amount of heat generated is the same, in the case of municipal waste compared to wood chips, paper and plastic sheets contain a large amount of volatile components, and the supply chute The volatile components are vaporized at the same time when the gas is supplied into the furnace body 1 from 3 and this gas tends to be burned in the secondary combustion chamber 11, and this heat cannot be transferred to the first bed SB. (2) When the circulation amount of the layer material FG is small, the temperature of the main combustion zone 7 is likely to rise, and when the table 9a is removed, the temperature of the thermal decomposition zone 4 is the same as that of the main combustion zone 7 or not. Since it is below, the volatile component is the layer material FG.
It can be seen that the smaller the amount is, the more easily it burns, that is, the volatile components do not burn at high temperature in many layer materials FG. However, in order to smoothly transfer the layer material FG from the first bed SB to the second bed FB, a sufficient layer material circulation amount is required. (3) In the case of municipal waste, the solid content (char) remaining in the second bed FB is small due to the large amount of volatile components, and the combustion efficiency of wood chips in the second bed FB is approximately 40 to 60%.
On the other hand, combustion efficiency in the case of municipal waste ≒ 20%
And low. And so on.

The present invention solves the above-mentioned problems by incinerating high-speed circulation type fluidized bed refuse which can efficiently incinerate self-burning even if it is a municipal waste having a large amount of volatile components and a low calorific value, even without auxiliary combustion of kerosene. The purpose is to provide a furnace.

[0008]

In order to solve the above-mentioned problems, the first means of the present invention is to arrange partition walls in the furnace body in the vertical direction, and incinerate chute on one side of each partition wall. The first bed for drying and preheating the incineration material supplied from the above is provided, and the second bed for combusting the incineration material is provided on the other side of the partition wall, and the layer material and the combustion gas blown up from the second bed are provided. A high-speed circulation type fluidized bed waste incineration system that bypasses the upper end of the partition wall and circulates it to the first bed side, and introduces this combustion exhaust gas into the second combustion chamber via the exhaust gas passage above the first bed for secondary combustion. In the furnace, a guide partition is formed by extending upward from the upper end of the partition, and a vertical guide wall along the guide partition is hung from a bypass guide wall arranged above the guide partition, and gas is supplied to both sides of the guide partition. Detour Forming a passage, opening from the upper part of the partition wall across the exhaust gas bypass passage to the exhaust gas passage, and circulating the layered material from the inlet of the gas bypass passage to the vicinity of the outlet of the burned material chute through the inlet of the exhaust gas passage. It is equipped with a sand falling pipe.

In addition to the above construction, the second means forms the vertical guide wall in a straight shape and hangs it down, and the connecting portion between the partition wall and the guide partition wall approaches the outer wall of the furnace body on the second bed side. The thermal decomposition zone is formed in a dogleg shape, narrows the passage above the second bed, and secures a large space above the first bed.

Further, in addition to the above construction, the third means is
A layer material collecting surface inclined downward from the outer wall of the furnace body to the vertical guide wall side was provided on the upper part of the bypass guide wall, and the trapped layer material was dropped to the first bed side through the exhaust gas passage. It is a thing.

[0011]

According to the above construction, of the layered material and the combustion gas blown up from the second bed, most of the layered material is introduced into the sand falling pipe and circulated in the vicinity of the outlet of the incinerator chute to generate the combustion gas. By introducing the gas into the gas bypass passage, it is possible to effectively burn the volatile component at a high temperature in a state in which the layer material is small. Next, the high temperature combustion exhaust gas discharged indirectly from the gas bypass passage by indirectly heating the sand falling pipe is thermally decomposed in the first bed and mixed with the rising combustion gas, and thus thermally decomposed in the first bed. The volatile component is surely burned, and this heat heats the first bed to promote dry pyrolysis, so that self-combustion can be continued. In addition, high temperature combustion exhaust gas,
Since the heating is performed by directly contacting the layered material input from the sand falling pipe, the layered material can be effectively heated. Therefore, even in the case of municipal waste having a low calorific value, it is possible to continue the combustion without the auxiliary combustion of kerosene and to self-burn it.

Further, according to the second structure, the layer material and the combustion gas blown up from the second bed are accelerated and raised by narrowing the passage above the second bed and spread out from the connecting portion. By decelerating with, it is possible to effectively introduce most of the layered material to the side of the sand falling pipe, and to prolong the residence time of the combustion gas in the gas bypass passage to burn the volatile components at a sufficiently high temperature. Furthermore, since a wide pyrolysis zone can be secured, the combustion gas pyrolyzed in the first bed can be efficiently burned at a high temperature to heat the first bed.

Further, the layer material collecting surface can capture the layer material entrained in the combustion exhaust gas and blown up into the secondary combustion chamber and effectively return the layer material to the first combustion chamber, which facilitates subsequent exhaust gas treatment. You can do it.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a high-speed circulation type fluidized bed waste incinerator according to the present invention will be described below with reference to FIGS. The same members as those of the related art are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 1, reference numeral 21 is a partition wall partitioning the first bed SB and the second bed FB, the lower end of which is immersed in the layer material FG on the first bed SB and the second bed FB to form an upper part. A lower partition wall (partition wall) 22 which is inclined so as to approach the rear partition wall side, and a guide partition wall 23 whose upper part is inclined so as to approach the front outer wall 1a side. By narrowing the upper passage of the main combustion zone (passage) 7 above SB by the connecting portion 21a of the lower partition wall (partition wall) 22 and the guide partition wall 23, the combustion gas and the layer material F
It is configured to accelerate the upward flow of G.

A detour guide wall 24 is provided above the partition wall 21 for detouring the lifted combustion gas downward.
A straight vertical guide wall 25 is hung from the partition wall 23 at a predetermined distance from the tip of the bypass guide wall 24, and gas bypass passages 26 are formed on both sides of the guide partition 23. There is.

In the vicinity of the connecting portion 21a of the partition wall 21 and the lower end of the vertical guide wall 25, a plurality of sand falling pipes 2 for circulating most of the layered material FG blown up by the main combustion zone 7.
7 is pierced, and the sand falling pipe 27 is provided on the extension line of the sand falling pipe 27 so as to be in the vicinity of the exit of the chute (incineration chute)
Is inclined downward from the connecting portion 21a so as to traverse the gas bypass passage 26 and penetrates the vertical guide wall 25 so that the exhaust gas passage 13
It is configured to be opened at an inlet of the above, and the layered material FG is configured to be put over the incineration object in the vicinity of the outlet of the chute 3.

The upper part of the main combustion zone 7 in the gas bypass passage 26 is constituted as a staying combustion zone 28 which spreads upward, and the rising flow of the combustion gas and the layer material FG from the main combustion zone 7 is decelerated. , The most part of the layer material FG is sent to the sand falling pipe 27, and the proportion of the layer material FG is almost zero by the residence combustion zone 28 which spreads further upward, and the residence time is made sufficiently long by the gas bypass passage 26. Thus, the volatile components are sufficiently burned in the state that the layer material FG is almost absent.

At the connecting portion 21a of the partition wall 21, the first bed S is
On the upper side of B, since the partition wall body 21 is formed in a dogleg shape, a wide thermal decomposition zone 29 is formed, and the high temperature combustion exhaust gas discharged from the gas bypass passage 26 is volatilized from the first bed SB. Mix with the ingredients and burn completely,
The heat can heat the incineration object input from the chute 3 and the first bed SB to accelerate drying and thermal decomposition.

The layer material FG introduced in the sand falling pipe 27
Since the sand falling pipe 27 penetrates the gas bypass passage 26, it is indirectly heated by the combustion exhaust gas, and the combustion exhaust gas bypassed upward from the outlet of the gas bypass passage 26 and the high temperature generated in the thermal decomposition zone 29 are generated. The layer material F in which the combustion exhaust gas is introduced into the exhaust gas passage 13 and discharged from the sand falling pipe 27
The layer material FG is heated in direct contact with G. The combustion exhaust gas after heating is introduced into the secondary combustion chamber 11 and completely combusted and discharged.

The detour guide wall 24 has a main slanted wall 24a which is slanted downwardly from the outer wall 1b, and a main slanted wall 24a which is slanted upwardly from the lower outer wall 1b of the main slanted wall 24a. Sub-sloping wall 24b connected to the middle part of the lower surface
And the upper surface of the main inclined wall 24a is the secondary combustion chamber 11
The layer material FG which has fallen and captured inside the exhaust gas passage 13
It is configured on the layer material recovery surface 31 for returning to the bed SB.

Reference numeral 32 is an auxiliary burner for starting which is arranged at the exit of the gas bypass passage 26, and 33 is an inspection window provided in the exhaust gas passage 13. Next, the operation of the above configuration will be described.

(A) The material to be incinerated supplied from the chute 3 into the furnace main body 1 is thrown in so that the layered material FG is covered from above in the vicinity of the outlet, so that relatively light paper or plastic sheets are scattered. In addition to being prevented, the incineration object is heated.

(B) The incineration object heated by the layer material FG and rapidly drawn onto the first bed SB is further promoted by heat drying and thermal decomposition, and the volatile components are elevated to the thermal decomposition zone 29, After the combustion exhaust gas discharged from the gas bypass passage 26 is mixed and sufficiently burned, the exhaust gas passage 1
In step 3, the layer material FG discharged from the sand falling pipe 27 is heated, introduced into the secondary combustion chamber 11, and further completely burned. The combustion heat generated in the thermal decomposition zone 29 is sufficiently transferred to the first bed SB and does not lower the temperature of the burned material. On the other hand, the solid matter that is not burned in the first bed SB is discharged by the combustion air supplied from the transfer air nozzle 5 into the second bed F.
Sent to B.

(C) In the first bed SB, the air blown by the high-speed combustion air nozzle 6 mainly burns the solids (char) of the refuse to form the main combustion zone 7, and the rising flow further causes The layer material FG is lifted while being gradually accelerated toward the upper side.

(D) Almost all of the layer material FG reaching the connecting portion 21a of the partition wall 21 is introduced into the sand falling pipe 27 and circulated in the vicinity of the outlet of the chute 3, and the combustion gas rising to the retention combustion zone 28 is discharged. By increasing the volume, the layer material FG is hardly contained, and the distance of the gas bypass passage 26 is increased so that the residence time is lengthened and the retention combustion zone 28 and the gas bypass passage 26 subsequent thereto are separated. The temperature of the combustion exhaust gas is raised by burning the volatile components in the combustion gas at a sufficiently high temperature.

(E) The combustion exhaust gas discharged from the gas bypass passage 26 through the sandfall pipe 27 by indirectly heating the layer material FG is
After reaching the thermal decomposition zone 29, the combustion gas is burned from the first bed SB, and then the layer material FG discharged from the sand falling pipe 27 is detoured upward to be heated and introduced into the secondary combustion chamber 11. Burned.

(F) Layer material FG entrained in combustion exhaust gas
In the secondary combustion chamber 11, is captured by the layer material recovery surface 31 on the upper surface of the bypass guide wall 24, and is naturally slid from the layer material recovery surface 31 into the exhaust gas passage 13 and returned to the first bed SB.

FIG. 3 is a graph showing the experimental results of operating the incinerator of the above-mentioned embodiment using municipal wastes having different calorific values, which is compared with the conventional type. The experimental conditions at this time were a burning rate of dust of 300 kg / h and an air ratio of about 1.8.

According to the results of this experiment, in the conventional incinerator, self-combustion was not possible unless the calorific value was 2800 kcal / kg or more, whereas in the incinerator of the present invention, 1200 kcal / kg of low-quality waste can also self-combust. You can see.

According to the above embodiment, (1) the combustion gas from which most of the layer material FG has been removed by the sand falling pipe 27 is introduced into the gas bypass passage 26, and the gas bypass passage 26 including the retention combustion zone 28 is used. By giving a sufficient residence time, it is possible to burn the volatile components at a sufficiently high temperature with a nourishing body having almost no layer material FG. Moreover, it is possible to secure a sufficient circulation amount of the layer material FG,
The layer material FG can be smoothly moved from the first bed SB to the second bed FB.

(2) Since the partition wall body 21 is formed in a V shape which is bent at the connecting portion 21a of the lower partition wall 22 and the guide partition wall 23, the layer material FG blown up from the second bed FB is raised while being accelerated, By decelerating above the connecting portion 21a, most of the layer material FG can be introduced into the sand falling pipe 27, and further, the velocity of the combustion gas moving in the gas bypass passage 26 is decelerated, and the retention necessary for combustion is achieved. You can give time. In addition, the first bed SB of the connecting portion 21a
The thermal decomposition zone 29 above the first bed SB can be secured widely on the side, and the volatile components thermally decomposed in the first bed SB can be sufficiently burned by the high temperature combustion exhaust gas discharged from the gas bypass passage 26. It is possible to heat the first bed SB with this heat to promote self-combustion. Further, directly from the gas bypass passage 26 or in the thermal decomposition zone 29.
Since the high temperature combustion exhaust gas discharged through the layer is directly contacted with the layer material FG discharged from the sand falling pipe 27, the layer material FG
Can be effectively heated.

(3) The layer material FG entrained in the combustion exhaust gas and entering the secondary combustion chamber 11 is captured by the layer material recovery surface 31 provided on the upper surface of the detour guide wall 24 and dropped into the exhaust gas passage 13. Since it is configured as described above, the number of times the layer material FG accumulated in the secondary combustion chamber 11 is removed by maintenance can be significantly reduced, and the layer material FG entrained in the exhaust gas treatment system can be reduced, so that the dust collector The capacity can also be reduced.

In the above embodiment, the sand falling pipe 27 penetrates the vertical guide wall 25 and opens in the exhaust gas passage 13.
It may be configured to open at the lower end of the vertical guide wall 25.

[0035]

As described above, according to the first configuration of the present invention, of the layered material and the combustion gas blown up from the second bed, most of the layered material is introduced into the sand falling pipe for incineration. By circulating the combustion gas in the vicinity of the outlet of the material chute and introducing the combustion gas into the gas bypass passage, it is possible to effectively burn the volatile components at a high temperature in a state where the layer material is small. Next, the high temperature combustion exhaust gas discharged indirectly from the gas bypass passage by indirectly heating the sand falling pipe is thermally decomposed in the first bed and mixed with the rising combustion gas, and thus thermally decomposed in the first bed. The volatile component can be reliably burned, and the first bed can be heated by this heat to promote dry pyrolysis, and self-combustion can be continued. Further, since the high temperature combustion exhaust gas is heated by directly contacting it with the layer material charged from the sand falling pipe, the layer material can be effectively heated. Therefore, even in the case of municipal waste having a low calorific value, it is possible to continue the combustion without the auxiliary combustion of kerosene and to self-burn it.

Further, according to the second structure, the layer material and the combustion gas blown up from the second bed are accelerated and raised by narrowing the passage above the second bed, and spread out from the connecting portion. By decelerating with, it is possible to effectively introduce most of the layered material to the side of the sand falling pipe, and to prolong the residence time of the combustion gas in the gas bypass passage to burn the volatile components at a sufficiently high temperature. Furthermore, since a wide pyrolysis zone can be secured, the combustion gas pyrolyzed in the first bed can be efficiently burned at a high temperature to heat the first bed.

Further, the layer material collecting surface can capture the layer material entrained in the combustion exhaust gas and blown up into the secondary combustion chamber and effectively return the layer material to the first combustion chamber, which facilitates subsequent exhaust gas treatment. You can do it.

[Brief description of drawings]

FIG. 1 is a side sectional view of essential parts showing an embodiment of a high-speed circulation type fluidized bed waste incinerator according to the present invention.

FIG. 2 is a sectional view taken along line I-I shown in FIG.

[Fig. 3] Fig. 3 is a graph showing the results of an experiment in which the same refuse incinerator was operated using municipal waste having different heating values.

FIG. 4 is a side sectional view showing a conventional high-speed circulation type fluidized bed incinerator.

[Fig. 5] Fig. 5 is a schematic diagram showing an operation test result in which wood chips are incinerated in a conventional high-speed circulation type fluidized bed incinerator.

FIG. 6 is a schematic diagram showing an operation test result of incinerating municipal solid waste in a conventional high-speed circulation type fluidized bed incinerator.

[Explanation of symbols]

 SB 1st bed FB 2nd bed FG Layer material 1 Furnace body 1a Front outer wall 1b Rear outer wall 3 Supply chute 5 Transfer air nozzle 6 High-speed combustion air nozzle 7 Main combustion zone 11 Secondary combustion chamber 13 Exhaust gas passage 21 Partition wall 21a Connection part 22 Lower partition wall 23 Guide partition wall 24 Detour guide wall 25 Vertical guide wall 26 Gas bypass passage 27 Sand-falling pipe 28 Stagnant combustion zone 29 Pyrolysis zone 31 Layer material recovery surface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michio Ito 5-3-8 Nishikujo, Konohana-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd. (72) Seiichi Nakai 5-chome, Nishikujo, Osaka, Osaka City, Osaka No. 28 in Hitachi Shipbuilding Co., Ltd.

Claims (3)

[Claims] 1. A vertical partition is arranged in the furnace body, and a first bed for drying and preheating an incineration material supplied from an incinerator chute is provided on one side of the partition, and the partition is provided. A second bed for burning the incineration material is provided on the other side part, and the layer material and the combustion gas blown up from the second bed are circulated to the first bed side while bypassing the upper end part of the partition wall, and the combustion exhaust gas is discharged. In a high-speed circulation type fluidized bed waste incinerator that introduces the second combustion chamber through an exhaust gas passage above the first bed to perform secondary combustion, a guide partition is formed by extending upward from the upper end of the partition. A vertical guide wall along the guide partition is hung from a bypass guide wall arranged above the guide partition to form a gas bypass passage on both sides of the guide partition, and the exhaust gas is crossed from the upper portion of the partition wall through the exhaust gas bypass passage. A high-speed circulation type fluidized bed type that has a sand falling pipe that opens toward the passage and circulates the layered material from the inlet of the gas bypass passage through the inlet of the exhaust gas passage to the vicinity of the outlet of the burned material chute Garbage incinerator. 2. A vertical guide wall is formed in a straight shape so as to hang down, and a partition wall and a guide partition wall are formed in a dogleg shape in which the connecting portion approaches the outer wall of the furnace main body on the second bed side. The high-speed circulation type fluidized bed waste incinerator according to claim 1, wherein the upper passage is narrowed and a space above the first bed is secured to be a pyrolysis zone. 3. A layer material collecting surface inclined downward from the outer wall of the furnace body to the outer wall of the exhaust gas guide is provided on the upper surface of the bypass guide wall, and the captured layer material is dropped to the first bed side through the exhaust gas passage. The high-speed circulation type fluidized bed waste incinerator according to claim 1 or 2, wherein the high-speed circulation type fluidized-bed waste incinerator is configured.