JP2532584B2 - Swirl type combustion furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention [Field of Industrial Application] The present invention relates to a swirl flow type combustion furnace, and more particularly to a direction in which a swirl flow formed in a furnace body by combustion air is crossed. The present invention relates to a swirl flow type combustion furnace provided with a powder supply pipe for supplying powder to be burned such as dry sludge particles, coal particles or incinerated ash by a carrier gas.

[Prior Art] Conventionally, when a powder to be burned (for example, dried sludge particles) is melted in a swirl flow type combustion furnace of this type, as shown in FIG.
Powder supply pipe for supplying burned powder such as dry sludge particles into the furnace body 20 by carrier gas in order to form a strong swirling flow
The openings of 32A to 32D are arranged with respect to the inside of the openings of the air supply pipes 31A to 31D for supplying combustion air to form a swirling flow in the furnace body 20 , and the powder to be burned. Was supplied in the tangential direction of the swirling flow.

[Problems to be solved] However, in this case, after the combustible powder such as dry sludge particles flows out from the powder supply pipes 32A to 32D, it goes straight without being diffused due to its weight, and 20 to 42 only in a narrow area of the inner peripheral surface of the body 20 (area where the angle α of the symmetry axis of the furnace body 20 and thus the central axis of the swirling flow is about 17 degrees)
There is a drawback that the wall surface of the furnace body 20 is remarkably thinned due to a synergistic effect with the high temperature atmosphere in the furnace body 20 as a result of the collision at a relatively large collision angle.

Therefore, in order to solve these drawbacks, the present invention uses a carrier gas to convey burned powder such as dried sludge particles toward the swirling flow so as to intersect with the swirling flow formed in the furnace body by the combustion air. Providing a swirl-flow type combustion furnace in which the powder supply pipe for supplying is arranged to diffuse the powder to be burned such as dry sludge particles and to expand the collision area with the inner surface of the furnace and reduce the collision angle. It is something to do.

(2) Configuration of the Invention [Means for Solving the Problem] The means for solving the problem provided by the present invention is to form a swirling flow in the furnace body by the combustion air supplied by the air supply pipes (11A to 11D). In a swirl flow type combustion furnace in which the powder to be burned is burned,
The powder supply pipes (12A to 12D) for supplying into (0) are -10 to 10 with respect to the cross section (a) orthogonal to the central axis (O) of the swirling flow.
Open in +45 degree angle range and central axis (O) of swirling flow
-30 to +30 degrees with respect to the line segment (B) connecting the central axis (O) of the swirling flow and the opening position of the powder supply pipe (12A to 12D) when projected onto the cross section (a) orthogonal to Is arranged in the furnace body (20) so that the powder to be burned can flow in from the powder supply pipes (12A to 12D) in the angle range of .

[Operation] In the swirl-flow combustion furnace according to the present invention, the swirl flow is directed to a position different from an air supply pipe that supplies combustion air for forming a swirl flow in the furnace body. (I) Dry sludge particles supplied by the powder supply pipe, since the opening of the powder supply pipe for supplying the combustible powder such as dry sludge particles, coal particles or incinerated ash by the carrier gas is arranged. , It has the function of letting out burned powder such as coal particles or incinerated ash in a direction crossing the swirl flow in the furnace body, and (ii) dried sludge particles, coal particles or burned powder such as incinerated ash. Of the swirling flow, and thereby (iii) the action of diffusing burned powder such as dry sludge flow, coal particles or incinerated ash over a wide range (iv) Dry sludge particles, coal particles Alternatively, the function of expanding the area where burned powder such as incinerated ash collides with the inner surface of the furnace and the angle at which burned powder such as dry sludge particles, coal particles or incinerated ash collide with the inner surface of the furnace are reduced. It acts, in other words, (v) suppresses erosion or thickness reduction of the inner peripheral surface of the furnace body by burned powder such as dry sludge particles, coal particles or incinerated ash.

[Examples] Next, the present invention will be specifically described with reference to the accompanying drawings.

FIG. 1 is a transverse sectional view showing an embodiment of a swirl flow type combustion furnace according to the present invention.

FIG. 2 is a longitudinal sectional view showing an embodiment of a swirl flow type combustion furnace according to the present invention.

First, the configuration of an embodiment of a swirl flow type combustion furnace according to the present invention will be described in detail.

Reference numeral 10 denotes a swirl flow type combustion furnace according to the present invention, in which combustion air is formed into a cylindrical (for example, cylindrical shape or polygonal cylinder shape of hexagonal cylinder or more) in order to form a swirl flow (see solid arrow). At least one (4 here) for feeding into the body 20
Air supply pipes 11A to 11D, and at least one (here four) powder supply pipes 12A to supply burned powder such as dry sludge particles, coal particles or incinerated ash and a carrier gas. Has 12D and.

The air supply pipes 11A to 11D are arranged in a cross section orthogonal to the central axis of the swirling flow extended toward the combustion gas outlet 22 of the furnace body 20.
The opening is in the angle range of 10 to +45 degrees and toward the chord direction of the furnace body 20 .

Here, the grounds that the air supply pipes 11A to 11D are opened at an angle of −10 degrees or more with respect to the cross section orthogonal to the central axis of the swirling flow are that the burned powder is scattered toward the combustion start burner 21,
It is to avoid or suppress the contamination of the combustion start burner 21 or its vicinity due to the combustion or melting.

In addition, the grounds that the air supply pipes 11A to 11D are opened at an angle of +45 degrees or less with respect to the cross section orthogonal to the central axis of the swirling flow are as follows.
This is to avoid that the combustion region of the powder to be burned is biased toward the combustion gas outlet 22 side and the temperature difference about the central axis of the swirling flow becomes large.

The powder supply pipes 12A to 12D are air supply pipes in order to prevent the burned powder from scattering toward the combustion start burner 21.
11A to 11D is preferably arranged at a height not higher than the height of the cross section, which is opened at an angle range of −10 to +45 degrees with respect to the cross section orthogonal to the central axis of the swirling flow and which is perpendicular to the central axis of the swirling flow. Center axis of swirling flow and powder supply pipes 12A-12D
It is preferable that the powder to be burned is made to flow in from the powder supply pipes 12A to 12D within an angle range of −30 to +30 degrees with respect to the line segment connecting to the opening position.

The arrangement of these powder supply pipes 12A to 12D is illustrated as follows:
It becomes like FIG. And FIG. That is, the powder supply pipe 12A
As shown in FIG. 2, -12D is −10 with respect to a cross section (shown by reference numeral a) orthogonal to the central axis of the swirling flow (shown by reference numeral O).
The opening of the swirling flow central axis and the powder supply pipes 12A to 12D when projected on a cross section orthogonal to the central axis of the swirling flow as shown in FIG. It is advisable to arrange it in the furnace body 20 so that the powder to be burned can be made to flow within an angle range of −30 to +30 degrees with respect to the line segment (indicated by the symbol B) connecting and.

In Fig. 1, the central axis of the swirling flow and the powder supply pipe 12A
The powder to be burned is introduced at an angle of 0 degree with respect to the line segment (indicated by the symbol B) connecting the opening position of ~ 12D,
Powder supply pipes 12A to 12D are arranged.

Here, the grounds that the powder supply pipes 12A to 12D are opened at an angle of −10 degrees or more with respect to the cross section orthogonal to the central axis of the swirling flow are that the burned powder is scattered toward the combustion start burner 21,
It is to avoid or suppress the contamination of the combustion start burner 21 or its vicinity due to the combustion or melting.

Further, the grounds for the powder supply pipes 12A to 12D being opened at an angle of +45 degrees or less with respect to the cross section orthogonal to the central axis of the swirling flow are as follows.
This is to avoid that the combustion region of the powder to be burned is biased toward the combustion gas outlet 22 side and the temperature difference about the central axis of the swirling flow becomes large.

On the other hand, the powder supply pipes 12A to 12D flow the burned powder at an angle of -30 degrees or more with respect to the line segment connecting the central axis of the swirling flow and the opening positions of the powder supply pipes 12A to 12D. The rationale is to avoid or suppress the reduction of the flow velocity of the swirling flow.

Further, the grounds for the powder supply pipes 12A to 12D to inject the burned powder at an angle of +30 degrees or less with respect to the line segment connecting the central axis of the swirling flow and the opening positions of the powder supply pipes 12A to 12D are as follows. It is to avoid or suppress that the burned powder is not sufficiently dispersed by the swirling flow and collides with the inner peripheral surface of the furnace body 20 at a large angle.

Further, the operation of one embodiment of the swirl flow type combustion furnace according to the present invention will be described in detail.

Combustion air is supplied into the furnace body 20 through the air supply pipes 11A to 11D as indicated by solid arrows, and a swirl flow is formed in the furnace body 20 about the axis of symmetry.

The powder to be burned is supplied toward the central part of the furnace body 20 and then to the swirl flow by a carrier gas such as pressurized air via the powder supply pipes 12A to 12D, and is diffused in a wide range as indicated by a dashed arrow by the swirl flow. (See FIG. 1).

After that, the powder to be burned is burned or heated and melted in the inner space and the wall surface of the furnace body 20 . The melted powder to be burnt becomes slag, and the centrifugal force associated with the swirling flow causes the furnace body
After being attached to the wall surface of 20 and flowing down, it is discharged from the combustion gas outlet 22 together with the combustion gas.

As described above, according to the swirl flow type combustion furnace 10 according to the present invention, burned powder such as dry sludge particles, coal particles or incinerated ash can be sufficiently dispersed in the furnace body 20 , and as a result, the furnace body
It is possible to satisfactorily burn the powder to be burned while suppressing erosion or thickness reduction on the inner peripheral surface of 20 .

In addition, one embodiment of the swirl flow type combustion furnace according to the present invention,
For better understanding, as a preferred application example, the case of melting treatment of dried sludge particles prepared from sewage sludge will be described with specific numerical values.

(Example) In FIGS. 1 and 2, the inner diameter of the furnace body 20 is 700 mm.
The inner diameters of the four air supply pipes 11A to 11D were all 90 mm, and the inner diameters of the four powder supply pipes 12A to 12D were all 40 mm.

The air supply pipes 11A to 11D are separated from each other by 90 degrees, and are separated from the center line of the cross section of the furnace body 20 by 280 mm,
And it was placed parallel to the center line. Powder supply pipe 12
A to 12D were separated from each other by 90 degrees, and were arranged on the center line of the cross section of the furnace body 20 .

The air supply pipes 11A to 11D and the powder supply pipes 12A to 12D were arranged at the same height, and were arranged so as to be inclined slightly downward with respect to the transverse sectional view of the furnace body 20 .

Outflow speed of combustion air from the air supply pipes 11A to 11D is 30m /
It was seconds. The outflow speed of the carrier gas from the powder supply pipes 12A to 12D was 20 m / sec.

The swirling flow velocity in the furnace body 20 was 8 to 25 m / sec.

The dried sludge particles had a particle size of about 60 to 600 μm, and collided with the inner peripheral surface of the furnace body 20 at an angle θ as viewed from the axis of symmetry and within a range of 70 degrees. The collision speed of the dry sludge particles on the inner peripheral surface of the furnace body 20 is 4 to 12 m / sec,
The impact angle of the dry sludge particles to the inner peripheral surface of the furnace body 20 was 10 to 28 degrees with respect to the tangential direction of the inner peripheral surface of the furnace body 20.

(Comparative Example) In FIG. 3, the inner diameter of the furnace body 20 was 700 mm, the inner diameters of the four air supply pipes 31A to 31D were all 100 mm, and the inner diameters of the four powder supply pipes 32A to 32D were all 40 mm.

The air supply pipes 31A to 31D and the powder supply pipes 32A to 32D are separated from each other by 90 degrees, are separated from the center line of the cross section of the furnace body 20 by 280 mm, and are arranged in parallel to the center line. Was there.

The air supply pipes 31A to 31D and the powder supply pipes 32A to 32D were arranged at the same height, and were arranged to be inclined slightly downward with respect to the cross section of the furnace body 20.

The outflow speed of air from the air supply pipes 31A to 31D was 30 m / sec, and the outflow speed of carrier gas from the powder supply pipes 32A to 32D was 20 m / sec.

The flow velocity of the swirling flow in the furnace body 20 was 8 to 23 m / sec.

The dried sludge particles had a particle size of about 60 to 600 μm, and collided with the peripheral surface inside the furnace body 20 at an angle α as viewed from the axis of symmetry within a range of 17 degrees. The collision speed of the dry sludge particles on the inner peripheral surface of the furnace body 20 is 5 to 19 m / sec, and the collision angle of the dry sludge particles on the inner peripheral surface of the furnace body 20 is the inner peripheral surface of the furnace body 20 . It was 20 to 42 degrees with respect to the tangential direction to the plane.

(3) Effects of the Invention As is clear from the above, in the swirl flow type combustion furnace according to the present invention, the swirling flow is formed in the furnace body by the combustion air supplied by the air supply pipe to burn the burned powder. In the swirl flow type combustion furnace, the powder supply pipe for supplying the burned powder into the furnace body has an angle range of −10 to +45 degrees with respect to a cross section orthogonal to the central axis of the swirl flow. When projected onto a cross section that is open and is orthogonal to the central axis of the swirling flow, the angle is within the range of −30 to +30 degrees with respect to the line segment connecting the central axis of the swirling flow and the opening position of the powder supply pipe. Since it is formed so that the burned powder can flow in from the powder supply pipe, (i) the burned powder such as dry sludge particles, coal particles, or incinerated ash supplied by the powder supply pipe is heated in the furnace. Has the effect of being able to flow transversely to the swirling flow in the body, thus (Ii) It has the effect that the combustible powder such as dry sludge particles, coal particles or incinerated ash can be combined sufficiently well with the swirling flow, and (iii) such as dry sludge particles, coal particles or incinerated ash. It has the effect of spreading the burned powder over a wide range and (iv) the effect of reducing the angle at which the burned powder such as dry sludge particles, coal particles or incinerated ash collides with the inner surface of the furnace body. v) It has the effect of suppressing the erosion or wall thinning of the inner surface of the furnace body due to burned powder such as dry sludge particles, coal particles or incinerated ash.

[Brief description of drawings]

FIG. 1 is a cross sectional view showing an embodiment of a swirl flow type combustion furnace according to the present invention, FIG. 2 is a vertical cross sectional view showing an embodiment of a swirl flow type combustion furnace according to the present invention, and FIG. It is a cross-sectional view showing a conventional swirl flow type combustion furnace. 10 ...... Swirl flow type combustion furnace 11A ~ 11D ...... Air supply pipe 12A ~ 12D ...... Powder supply pipe 20 ...... Furnace body 21 ...... Combustion start burner 22 ...... Combustion gas outlet

Claims (1)

(57) [Claims] 1. A swirl flow type combustion furnace in which a swirling flow is formed in a furnace by combustion air supplied by air supply pipes (11A to 11D) to burn the powder to be burned. Of the powder supply pipes (12A to 12D) for supplying the gas into the furnace body (20) are opened in an angle range of −10 to +45 degrees with respect to the cross section (a) orthogonal to the central axis (O) of the swirling flow. And a line connecting the central axis (O) of the swirling flow and the opening positions of the powder supply pipes (12A to 12D) when projected onto the cross section (a) orthogonal to the central axis (O) of the swirling flow. -30 for minutes (b)
A furnace body (20) so that the powder to be burned can flow in from the powder supply pipes (12A to 12D) within an angle range of up to +30 degrees.
A swirl flow type combustion furnace characterized by being arranged in