JPH02217710A - Burner - Google Patents

Abstract

PURPOSE:To prevent the accumulation and attachment of slag by providing a cooling device which is provided with a cylindrical duct which is opened to a low temperature gas guide space near an end section of the cylindrical body of a casing and a combustion gas outlet which discharges the combustion gas cooled by a low temperature gas. CONSTITUTION:In a combustion gas cooling device 40 a low temperature gas is supplied into a low temperature gas guide space 41a which is formed between the cylindrical body 41 of a casing and a cylindrical duct 42 by a low temperature gas supply pipe 43, and the low temperature gas is transferred toward the open section of a combustion gas outlet 35, cooling the inside of the low temperature gas guide space 41a to a temperature lower than the solidification temperature of molten dust and then the low temperature gas is discharged from the opening 42a to the inside space 42b in the cylindrical duct 42. In the inside space 42b the combustion gas supplied from the combustion gas outlet 35 is mixed with the low temperature gas in a short time and cooled rapidly to an appropriate temperature. The slag in minute particles contained in the combustion gas is changed thereby into fly ash that has no adhesive property in a short time and the slag never attaches the inner circumferential face of the cylindrical duct 42 because the inner circumferential face of the cylindrical duct is cooled more than the low temperature gas.

Description

Detailed Description of the Invention] (1.1 Object of the Invention [Field of Industrial Application] The present invention relates to a combustion device, and in particular, the present invention relates to a combustion apparatus, in particular a combustion furnace that burns and heats a powder to be combusted to generate combustion gas and After the slag is introduced into a slag separation chamber or a slag separation furnace and separated into slag and combustion gas, low temperature gas is supplied to cool the combustion gas and the combustion gas is sent to the subsequent equipment via the combustion gas outlet. It is used in combustion equipment to convert the fine particulate slag present in fly ash into non-adhesive fly ash.

[Prior Art] Conventionally, in this type of combustion apparatus, for example, as in the combustion apparatus (2) shown in FIG. The remaining part burns and heats and melts, and the remaining part adheres to the inner wall surface of the combustion chamber 22 due to the centrifugal force accompanying the swirling flow and burns and heats and melts, resulting in combustion gas and slag, and fi) combustion. After the gas is released as it is from the combustion gas outlet 26, it enters the slag separation space 3, which is comparable to a slab separator.
4 through its combustion gas outlet 33, and (ii) the slag is carried by the combustion gas to the combustion gas outlet 26.
Except for a part that goes out from the combustion chamber, most of it flows down along the inner wall surface of the combustion chamber 22, and then flows down along the inner wall surface of the combustion gas outlet 26 and is discharged from the combustion chamber 22, resulting in slag separation similar to that of a slag separator. The combustion gas was dripping into space 34 from population 33.

In the slag separation space 34, which is comparable to a slag separator, the combustion gas discharged from the combustion gas population 33 and the dripped slag are separated from each other, and the combustion gas is passed through the combustion gas outlet 35 to a subsequent processing device (for example, heat recovery 50, etc.), and the slag was discharged from the slag outlet 36 to a subsequent slag treatment device.

At the combustion gas outlet 35, a low-temperature gas supply pipe is connected to reduce the temperature of the combustion gas to protect the subsequent processing equipment and to convert particulate slag contained in the combustion gas into non-adhesive fly ash. A suitable low temperature gas is discharged from the 35A, thereby producing a high temperature (e.g. 13A).
00 to 1,500°C) was cooled to a temperature of 1,000°C or less.

[Problem to be solved 1 However, in the conventional combustion device IO, the combustion gas outlet 3
Appropriate low-temperature gas is directly discharged from the low-temperature gas supply pipe 35A that opens on the inner circumferential surface of No.
(i) High-temperature combustion gas and low-temperature gas could not be mixed in a short time, and the high-temperature combustion gas could be uniformly cooled to a predetermined temperature of 1000°C or less in a short time. Furthermore, when mixing and cooling low-temperature gas, the ash in the high-temperature combustion gas becomes sticky, which cannot be avoided.
i) There is a drawback that slag accumulates and adheres to the downstream side of the opening of the low temperature gas supply pipe 35A, reducing the cross-sectional area of the combustion gas outlet 35 in a short time. The combustion gas outlet 3 stops intermittently in short cycles.
Disadvantage: By opening a working hole (not shown) formed on the downstream side of the low temperature gas supply pipe 35A, it is necessary to scrape and remove the accumulated slabs from the downstream side of the opening of the low temperature gas supply pipe 35A using a working rod. As a result, M maintenance work was complicated and operational efficiency could not be improved.

Therefore, the present invention aims to eliminate these drawbacks (i.e., to rapidly cool the combustion gas to the slag separation chamber attached to the incinerator or to the combustion gas outlet of the slag separation furnace, so that the ash content in the combustion gas becomes sticky). It is an object of the present invention to provide a combustion device including a cooling device for surrounding the head.

(2) Structure of the Invention [Means for Solving the Problems] The means for solving the problems provided by the present invention is as follows. After the combustion gas and the slab are separated from each other by introducing the combustion gas into a separation chamber or slag separation furnace, when the combustion gas is discharged from the slag separation chamber or slag separation furnace through the combustion gas outlet, low temperature gas is supplied to the combustion gas outlet. In a combustion device in which low temperature gas is supplied from a pipe to cool the combustion gas, one end is open to the combustion gas outlet (al), and a low temperature gas supply pipe is opened near the other end. A low temperature gas guide space is secured between a casing cylinder having an opening and an inner circumferential surface of the casing cylinder, and a low temperature gas guide space is provided between the casing cylinder and the fbl casing cylinder. ＠A cylindrical duct that is opened in at least one place with respect to the gas guide space; A combustion device characterized in that it is provided with a cooling device that includes a combustion gas outlet and another combustion gas outlet.

[Function] The combustion device according to the present invention separates the combustion gas and slag by introducing the combustion gas and slag produced by burning and heating and melting the body to be burned in the combustion furnace into the slag separation chamber or the slag separation furnace. A combustion device that cools the combustion gas by supplying low-temperature gas from a low-temperature gas supply pipe to the combustion gas outlet when the combustion gas is discharged from the slag separation chamber or slag separation furnace through the combustion gas outlet after separating the combustion gas from each other. In the case of the combustion gas outlet, (a) a casing cylinder having one end opened to the combustion gas outlet and a low temperature gas supply pipe opened near the other end; It is arranged inside to ensure a low-temperature gas guide space between the inner circumferential surface of the casing cylinder and is opened at least in one place to the low-temperature gas guide space near one end of the casing cylinder. A cooling device comprising: a cylindrical duct; and (c) another combustion gas outlet opened near the other end of the cylindrical duct for discharging combustion gas cooled by low-temperature gas. Because it is characterized by being arranged.

fit The combustion gas is mixed with low-temperature gas in a short time at the combustion gas outlet of the slag separation chamber or the slag separation furnace, and has the effect of homogeneously rapidly cooling it. It acts to avoid the accumulation and adhesion of slag on the downstream side of the opening of the low-temperature gas supply pipe that supplies the gas, and therefore fii
il low filtration gas It has the effect of avoiding the need to stop the operation of the combustion equipment in order to remove the slag that has accumulated and adhered to the downstream side of the low feed gas supply pipe, and as a result, fivl maintenance work is reduced and operational efficiency is improved. It acts to enhance.

[Example] Next, the combustion apparatus according to the present invention will be described in detail by giving examples thereof. However, the examples described below are described to facilitate or accelerate the understanding of the present invention, and are not described to limit the present invention.

In other words, each member disclosed in the embodiments described below includes all design changes and equivalent substitutions that fall within the spirit and technical scope of the present invention.

FIG. 1 is a partial vertical sectional view showing a first embodiment of the combustion apparatus according to the present invention, in which the slag separation is connected to a combustion gas outlet 26 similar to that of a swirling flow type #l kiln. A case is shown in which the combustion gas guide passage 32 in a row of houses has a collision part 32A.

FIG. 2 is a partial vertical sectional view showing a second embodiment of the combustion apparatus according to the present invention, in which a row of slag separators are connected to a combustion gas outlet 26 of a swirling flow combustion furnace. This shows the case where the combustion gas guide passage 32 does not have a collision part.

First, the structure and operation of a first embodiment of the combustion apparatus according to the present invention will be described in detail with reference to FIG. Here, for convenience, the case where the present invention is applied to a swirling flow type combustion furnace will be exemplified, but the present invention is not limited to this, and also includes the case where it is applied to other types of combustion furnaces.

Reference numeral (2) is a combustion apparatus according to the present invention, which includes a swirling flow type combustion furnace section and a slag separator arranged below the swirling flow type combustion furnace section. The slag separation chamber 30 is provided with a combustion gas cooling device for cooling the combustion gas. The combustion gas cooled by the combustion gas cooling device 40 is appropriately processed by a subsequent combustion gas processing device (for example, a heat recovery device 4 for recovering heat from the combustion gas; this case will be described below).

Swirling flow type combustion furnaces supply combustion air to a cylindrical combustion chamber 22 (for example, cylindrical or polygonal cylindrical shape of hexagonal cylinder or more) formed in a furnace body 21 to form a swirling flow. at least one (for example four) air supply pipes 23 for
and at least one (for example, four) powder supply pipes 24 for supplying the dry sludge particles 1, a substance to be combusted such as coal particles or incinerated ash, and a carrier gas to the combustion chamber 22 in the furnace body 21; The combustion chamber 22 is arranged at the top of the furnace body 21.
A combustion start burner 25 that emits a flame to start combustion, and a combustion gas outlet 26 that is formed at the lower end of the furnace body 21 and discharges combustion gas and slag or combustion ash from the combustion chamber 22. It is equipped with

The slag chamber is the combustion gas outlet 2 of the swirling flow type combustion furnace.
a combustion gas guide passage 32 which is open at one end with respect to 6 and is formed in the furnace body 31 and guides combustion gas and slag or combustion ash discharged from a combustion chamber 22 similar to a swirling flow combustion furnace; The top portion, that is, the combustion gas port 33 is opened to the other end of the combustion gas guide passage 32, and the furnace body 31
A slag separation space 34 is formed to separate combustion gas and slag or combustion ash from each other, and one end is open to the slag separation space 34 and the other end is open to the subsequent heat recovery device 4. A combustion gas outlet 35 communicated with the gas cooling device and arranged to discharge combustion gas from the slag separation space 34, and a combustion gas outlet 35 having one end opened to the bottom of the slag separation space 34 and the other end. is connected to a subsequent slag treatment device (not shown) and has a slag outlet 36 for discharging slag from the slag separation space 34.

The combustion gas guide passage 32 is a meandering passage or a curved passage, and the combustion gas discharged from the combustion gas outlet 26 of the swirling flow type combustion furnace is collided with the combustion gas to attenuate or eliminate the swirling flow, and the surface Collision part 3 where combustion ash contained in combustion gas is collected by the slab attached to
Contains 2A.

The combustion gas cooling device 40 includes a casing cylinder 41 whose one end communicates with the open end of the combustion gas outlet 35, and a casing cylinder 41 that is disposed inside the casing cylinder 41 and has one end that communicates with the open end of the combustion gas outlet 35. A metal cylindrical duct 42 having at least one opening 42a that opens to a low temperature gas guide space 41a formed between the casing cylinder 41 and the inner circumferential surface of the casing cylinder 41 in the vicinity of the casing cylinder. A low temperature gas guide space 41a is opened near the other end of the duct 41 and supplies low temperature gas to the low temperature gas guide space 41a formed between the inner peripheral surface of the casing cylinder 41 and the outer peripheral surface of the cylindrical duct 42. It includes a gas supply pipe 43 and a combustion gas outlet 44 that is opened near the other end of the cylindrical duct 42 and guides cooled combustion gas to the outside.

The cylindrical duct 42 preferably has an inner diameter larger than the inner diameter of the combustion gas outlet 35 in order to avoid direct collision with high-temperature combustion gas, and also has an inner diameter larger than the inner diameter of the combustion gas outlet 35. It is preferable to have an extension axis parallel to .

A cold gas guide space 41 is provided by a cold gas supply pipe 43.
The low temperature gas supplied to the internal space 42b of the cylindrical duct 42 through the opening 42a and the opening 42a is 150 to 2
Preferably, exhaust gas, exhaust steam or air having a temperature of around 50° C. is used.

The heat recovery device includes a device main body 51 that communicates with the other end of the combustion gas outlet 44 and receives combustion gas cooled to a temperature of 1000° C. or less, and a subsequent combustion gas processing device ( Combustion gas outlet 5 for discharging the heat-exchanged combustion gas toward, for example, a desulfurization device (not shown)
2, an air supply pipe 53 for supplying outside air to the device main body 51, and air for discharging heat-exchanged air (i.e. heated air) from the device main body 51 and supplying it to the air supply pipe 23, etc. A discharge pipe 54 is provided.

With reference to FIG. 1, the operation of the first embodiment of the combustion apparatus according to the present invention will be described in detail.

In the swirling flow type combustion furnace, combustion air is supplied into the combustion chamber 22 of the furnace body 21 as shown by the solid arrow A1 through the air supply pipe 23, and the combustion air is fed into the combustion chamber 22 of the furnace body 21 with its axis of symmetry as the center. A swirling flow is formed as shown by the solid arrow A.

The powder to be combusted is supplied to the central part of the combustion chamber 22 of the furnace body 21 by a carrier gas such as heated air through the powder supply pipe 24, as shown by the broken line arrow B1, and further towards the swirling flow (solid line arrow All). Due to the swirling flow, it is diffused over a wide range as shown by the broken line arrow B2.

Combustion of the powder to be combusted is started by temporarily releasing flame into the combustion chamber 22 by the combustion start burner 25, and combustion or heating and melting is continued in the internal space and inner wall surface of the combustion chamber 22. . The burnt powder becomes combustion gas and combustion ash, and it rides on the swirling flow as shown by the solid line arrow A.
As shown at 3, the combustion gas is discharged from the combustion gas outlet 26. Further, the melted powder to be combusted becomes slag, which adheres to one inner wall of the combustion chamber 22 and flows down due to the centrifugal force accompanying the swirling flow, and then flows from the combustion gas outlet 026 as shown by the broken line arrow B. It is discharged together with combustion gas (solid arrow A,).

Although the combustion gas discharged from the combustion gas outlet 26 still maintains a swirling flow as shown by the solid arrow A,
By colliding with a collision portion 32A formed in a combustion gas guide passage 32 comparable to a slag separator, the swirling flow is weakened.

The combustion ash carried from the combustion chamber 22 by the combustion gas is
As the combustion gas collides with the collision part 32A and is diffused into the internal space of the combustion gas guide passage 32, the collision part 32A
The slag is collected by the slag flowing down the inner wall surface of the combustion gas guide passage 32, including the surface of the combustion gas guide passage 32.

As a result, the combustion gas is separated into slag from the other end of the combustion gas guide passage 32, that is, the combustion gas population 33, as shown by the solid line arrow A4, with the swirling flow sufficiently attenuated or eliminated and the combustion ash sufficiently removed. It is discharged towards the slag separation space 34 of the chamber 30. Similarly, after the slab flows down the inner wall surface of the combustion gas guide passage 32, it is dripped from the other end, that is, the combustion gas inlet 33, into the slab separation space 34 as shown by the broken line arrow B4.
Since the swirling flow of the combustion gas is substantially attenuated or eliminated, the dropped slag is not scattered toward the inner wall surface of the slab separation space 34, and flows inside the slab separation space 34 onto the floor. Dropped directly onto the surface.

In the slag separation space 34 of the slag separation room material, high temperature (
For example, the combustion gas at a temperature of 1300 to 1500°C is discharged from the combustion gas outlet 35 toward the subsequent combustion gas cooling device as shown by the solid arrow A6. Further, the slag is discharged from a slag outlet 36 formed at the bottom to a subsequent slag treatment device (not shown) as indicated by a broken line arrow B.

In a combustion gas cooling device, low temperature gas is supplied by a low temperature gas supply pipe 43 as shown by arrow C1 (casing cylinder 41
The low temperature gas is supplied into a low temperature gas guide space 41a formed between the cylindrical duct 42 and the low temperature gas guide space 41a. The low temperature gas flows in the direction of the opening of the combustion gas outlet 35 (in other words, the direction of the combustion gas) while cooling the cylindrical duct 42 to a temperature lower than the solidification temperature of the slag, that is, the molten dust, as shown by the arrow C3 in the low temperature gas guide space 41a. (in the direction opposite to the direction of movement) and is discharged from the opening 42a into the internal space 42b of the cylindrical duct 42. Incidentally, it is preferable that the temperature of the cylindrical duct 42 is maintained at a temperature lower than the melting temperature of the slag by 300° C. or more.

In the internal space 42b of the cylindrical duct 42, the combustion gas outlet 3
As shown by the solid line arrow As from 5 (the supplied combustion gas is mixed with the supplied low temperature gas in a short period of time as shown by the solid line arrow C2), the combustion gas is mixed with the supplied low temperature gas to an appropriate temperature of 1000° C. or less (preferably,
The slab is rapidly cooled to a temperature that is more than 100°C below the melting temperature of the slab.

As a result, the particulate slag contained in the combustion gas is converted into non-adhesive fly ash in a short time, and the inner peripheral surface of the cylindrical duct 42 is cooled by the low-temperature gas, so that the cylindrical duct 42 It is not attached to the inner circumferential surface of the

Combustion gas (also referred to as cooled combustion gas) in which particulate slag is converted into fly ash in the internal space 42b of the cylindrical duct 42 is supplied to the heat recovery device 50 through the combustion gas outlet 44 as shown by the solid line arrow A6. and the device body 5
After passing through the interior space of 1.

The combustion gas outlet 52 also points toward the subsequent device with a solid line arrow A?
It is especially emitted when it is shown as . At this time, in the device main body 51,
Outside air is supplied from the air supply pipe 53 as shown by the solid arrow E1, and after exchanging heat with the cooling combustion gas, is discharged from the air exhaust pipe 54 as shown by the solid arrow E□.

Furthermore, with reference to FIG. 2, the structure and operation of a second embodiment of the combustion apparatus according to the present invention will be described in detail.

The second embodiment is based on a collision part 32 in the combustion gas guide passage 32.
This embodiment has the same structure and operation as the first embodiment except that A is removed.

In other words, in the second embodiment, the collision part 32A in the combustion gas guide passage 32 in the first embodiment is removed, and the flow from the combustion gas outlet 26 of the swirling flow combustion furnace 20 to the slag separation chamber is Combustion gas is directly supplied to the combustion gas population 33 (for example, via a right cylindrical passage as shown in FIG. 2), but for the present invention, substantially the first
Since there is no difference in structure and operation from the illustrated embodiment, that is, the first embodiment, the same reference numerals are given to the same members as in the first embodiment, and other specific explanations will be omitted.

Incidentally, although the above description has been made assuming that combustion air is not supplied to the slag separation chamber 30, the present invention is not limited to this. In other words, the present invention includes a case where the slab separator is formed as a secondary combustion furnace having a slag separation function, that is, a slag separation furnace.

In addition, in order to further deepen the understanding of one embodiment of the combustion apparatus according to the present invention, as a preferred application example, dried sludge particles made from sewage sludge are heated and melted in a swirling flow type combustion furnace shown in Fig. 1. The case will be explained using specific numerical values.

At this time, the ash contained in the dried sludge particles has a content m of 30 to 50% of the total weight of the dried sludge particles, a melting point temperature of 1100 to 1200 °C, and a pour point temperature of 1150 °C.
The temperature was ~1250°C.

11 and FIG. 1, the combustion device has an inner diameter of the combustion chamber 22 of 2.
There were 50 questions, the deflection distance between the combustion gas outlet 26 and the combustion gas population 33 was 150 questions, and the collision part 32A was an inclined plane.

Further, the inner diameter of the combustion gas outlet 35 is 250 mm, and the casing cylinder 4I included in the combustion gas cooling device 40
and the inner diameter of the opening 42a is 600 mm and 60 mm, respectively.
It was supposed to be 0mm. The lengths of the casing cylinder 41 and the cylindrical duct 42 were both 14 flOmm.

Air supply pipe 23 to combustion chamber 22 of swirling flow type combustion furnace 20
The amount of combustion air supplied through 100-160
Nm' It was 7 o'clock. The amount of dried sludge particles supplied via the powder supply pipe 24 was 7 to 15 kg/hour. The flow velocity of the combustion gas at the combustion gas outlet 26 of the swirling flow combustion furnace 20 was 30 to 50 m/sec.

At this time, 95 to 97% by weight of the ash contained in the dried sludge particles was discharged as slag from a slag outlet 36 similar to a slag separator. Also, the combustion gas outlet 3 of the slag separation chamber 30
The amount of dust contained in the combustion gas discharged from No. 5 was 0.3 to 0.7 g/Nm3 on a dry gas basis. The combustion gas discharged from the combustion gas outlet 35 has a temperature of 13
50~1450℃ and flow rate 500~90ON
It was 7 o'clock.

In the combustion gas cooling device 40, the low-temperature gas supplied by the low-temperature gas supply pipe 43 was air containing 70-90% by volume of moisture and heated to 130-200°C. Cold gas was supplied at a rate of 500-80 ONm'/hr.

Thereby, the combustion gas given from the combustion gas outlet 35 was mixed with low temperature gas in the internal space 42b of the cylindrical duct 42, and after being sufficiently cooled, was discharged from the combustion gas outlet 44. The residence time of the combustion gas in the internal space 42b of the cylindrical duct 42 is approximately 0.15 seconds, and the temperature of the combustion gas at the combustion gas outlet 44 is 800 to 850°C.
Met. At this time, the temperature (theoretical temperature) at the inner peripheral surface of the cylindrical duct 42 was 550°C.

No slab was visible on the inner metal wall of the cylindrical duct 42, which was similar to that of a combustion gas cooling device, even after 200 hours of operation.

” Except for removing the combustion gas cooling device 40 and opening the low-temperature gas supply pipe directly to the combustion gas outlet 35,
The example was repeated.

As a result, slag adhered to the downstream side of the opening of the low-temperature gas supply pipe, and unless it was removed by scraping with a work rod once every 20 hours, operation would be hindered.

By comparing the above-described embodiments and comparative examples, it is clear that according to the present invention, it is possible to prevent slag from adhering to the inner surface of the combustion gas outlet 35, and as a result, it is possible to prevent workers from getting high 'IKA'!
It is possible to avoid scraping and removing the slab at the boundary.

In other words, according to the present invention, maintenance work can be reduced and operational efficiency can be improved.

Although the above description has been made regarding the case where sewage sludge is melted, the present invention is not limited to this, and can also be applied to cases where exhaust gas from a coal gasifier is cooled.

(3) Effects of the invention As is clear from the above, the combustion device according to the present invention has the following effects:
The combustion gas and slag produced by burning the powder to be combusted in the combustion furnace and heating and melting are introduced into a slag separation chamber or slag separation furnace to separate the combustion gas and slag from each other, and then the combustion gas is separated into slag. In a combustion device that cools the combustion gas by supplying low-temperature gas from a low-temperature gas supply pipe to the combustion gas outlet when discharging the combustion gas from the combustion gas outlet from a chamber or slab separation furnace, (a) One end is open to the combustion gas outlet,
A low-temperature gas guide space is secured between the casing cylinder with a low-temperature gas supply pipe opened near the other end and the inner peripheral surface of the tb+ casing cylinder, which is arranged inside the casing cylinder. and (C) a cylindrical duct that is opened near one end of the casing cylinder to the low-temperature gas guide space; The present invention is characterized in that a cooling device comprising another combustion gas outlet for discharging cooled combustion gas is provided.

(il) It has the effect of mixing the combustion gas with low-temperature gas in a short time at the combustion gas outlet of the slab separation chamber or slag separation furnace and rapidly cooling it homogeneously. This has the effect of avoiding the accumulation and adhesion of slag on the downstream side of the opening of the low-temperature gas supply pipe that supplies low-temperature gas. This has the effect of making it possible to avoid stopping the operation of the combustion apparatus for removal, and as a result, it has the effect of reducing (IVl) maintenance work and increasing operational efficiency.

[Brief explanation of the drawing]

FIG. 1 is a partial vertical sectional view showing a first embodiment of the combustion device according to the present invention, and FIG. 2 is a partial longitudinal sectional view showing a second embodiment of the combustion device according to the present invention.
FIG. 3 is a partial longitudinal sectional view showing a conventional example. 10・・・・・・・・・・・・・・・ Combustion device 20・
・・・・・・・・・・・・Swirling flow type combustion furnace 21・
・・・・・・・・・・・・Furnace body 22・・・・・・・・・
... Combustion chamber 23 ... Air supply pipe 24 ... Powder supply pipe 25 ... ...... Combustion start burner 26
...... Combustion gas outlet 30...
...... Slag separation room 31...
...... Furnace body 32 ......
・Combustion gas guide passage 32A... ...Collision part

Claims (1)

[Claims] After the combustion gas and slag produced by burning and heating the powder to be combusted in a combustion furnace and the slag are introduced into a slag separation chamber or a slag separation furnace, the combustion gas and slag are separated from each other. , in a combustion device in which low temperature gas is supplied from a low temperature gas supply pipe to the combustion gas outlet to cool the combustion gas when the combustion gas is discharged from the slag separation chamber or the slag separation furnace through the combustion gas outlet, the combustion gas outlet (a) One end is open to the combustion gas outlet,
A casing cylinder in which a low-temperature gas supply pipe is opened near the other end, and (b) a low-temperature gas guide space disposed inside the casing cylinder and the inner peripheral surface of the casing cylinder. (c) A cylindrical duct which is opened near the other end of the cylindrical duct and has at least one opening near one end of the casing cylinder to the low temperature gas guide space; 1. A combustion device characterized in that a cooling device is provided, the cooling device comprising another combustion gas outlet for discharging combustion gas cooled by the gas.