JP3310815B2 - Melt combustion equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for burning coal at a high temperature,
The present invention relates to a facility for melting (slugging) ash, removing the ash by water granulation or the like, and completely burning the generated combustion gas and unreacted char.

[0002]

2. Description of the Related Art FIG. 2 is a schematic longitudinal sectional view showing an example of a conventional melting and burning facility, and FIG. 3 is a view taken in the direction of arrows III-III in FIG.

First, in FIG. 2, (1) is a cylindrical main combustor whose axis is substantially vertical, and the lower end is narrowed down in a funnel shape to form a throat (2). This main combustor (1)
A fuel injection nozzle (3) oriented in the axial direction and a secondary air injection nozzle (4) oriented in the tangential direction are provided in the upper part of the nozzle. (5) is a cylindrical sub-combustor whose axis is inclined with respect to the horizontal. The lower end of the throat (2) is connected to the high position end (the left end in FIG. 2) and the low position end (FIG. 2 is provided with a slag tap (6). (7) is a slug bin. The main combustor (1) and the sub-combustor (5) form a melting combustion device.
(8) is a vertical gas duct, the lower end of which is connected to the lower position end. The upstream end (the left end in FIG. 2) of the horizontal gas duct (9) is connected to the upper end of the vertical gas duct (8). Reference numeral (10) denotes a boiler furnace as a combustion furnace, which is connected to the downstream end (the right end in FIG. 2) of the horizontal gas duct (9). This boiler furnace (10) is provided with a tertiary air injection nozzle (11) at the inlet.

Next, the operation of such equipment will be described. First, pulverized coal is injected from a fuel injection nozzle (3) above a cylindrical vertical main combustor (1) at a certain spread angle as a mixture with primary air. On the other hand, the secondary air is tangentially injected from the secondary air injection nozzle (4) also in the upper part of the main combustor (1). The injected pulverized coal gasifies and burns at high temperature while rotating at high speed together with the secondary air to reach the throat (2) at the outlet. At this time, the ash contained in the pulverized coal melts at a high temperature, reaches the wall of the main combustor (1) by centrifugal force, and forms a slag layer flowing down the wall. This slag layer flows down the throat (2) located at the lower end of the main combustor (1), flows at the bottom of the sub-combustor (5), and downstream of the sub-combustor (5) (right end in FIG. 3). The slag tap (6) flows down the slag bin (7) and is discharged. The combustion gas from which the molten slag has been removed reaches a boiler furnace (10) via a vertical gas duct (8) having a shape which reverses and rises from the outlet of the sub-combustor (5), and further passes through a horizontal gas duct (9). The combustion gas and the unreacted char generated in the melting and burning device are converted into a tertiary air injection nozzle (11).
Complete combustion by tertiary air introduced from

[0005] The shape of the outlet of the horizontal gas duct (9) is as follows.
As shown in FIG. 3, the tertiary air nozzle (11) is of a vertically long circular shape for the same reason as shown in FIG. 3 in order to minimize the bend area of the furnace wall heat transfer tube (not shown) of the boiler furnace (10). ) Are disposed above and below the horizontal gas duct (9).

In a conventional coal-fired boiler, a large amount of coal ash is generated as a residue, so disposal and management of the coal ash are difficult. However, in the case of melting and burning, the coal is burned at a high temperature to convert the ash into molten slag. Thereafter, it is solidified by water granulation or the like to reduce the bulk to about half that of coal ash, and can be used as a building material. Therefore, the life of the ash disposal yard is prolonged, and scattering of ash, which is a pollutant, and elution into water are prevented. Welding combustion also suppresses heat transfer performance degradation and ash erosion due to ash adhering to the boiler heat transfer tubes.

[0007]

More than 99.5% of the slag melted by the melting and burning device is discharged out of the system through the slag discharge hole (7). However, less than 0.5% of the molten slag not captured by the slag discharge hole (6) rises along the wall of the vertical gas duct (8), and further rises along the wall of the horizontal duct (9). Reach the combustion section. The molten slag that has exited the horizontal gas duct (9) is cooled and solidified by tertiary air supplied from tertiary air nozzles (11) disposed above and below the slag. This cooled and solidified slag layer
Since it grows with time and covers the front surface of the tertiary air nozzle (11) during a long operation, the state of diffusion of the tertiary air with respect to the combustion gas deteriorates, and unburned components remain at the outlet of the boiler furnace (10).

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention provides a throat having a substantially vertical cylindrical axis, a lower end narrowed in a funnel shape, and a throat at an upper part. A main combustor having a fuel injection nozzle facing the air and an air injection nozzle facing the tangential direction, a cylindrical shape whose axis is inclined with respect to the horizontal, the lower end of the throat connected to the high position end, and the low position end A sub-combustor having a slag discharge port, a vertical gas duct having a lower end connected to the lower end, a horizontal gas duct having an upstream end connected to an upper end of the vertical gas duct, and a horizontal gas duct having an upstream end connected to the upper end of the vertical gas duct And a combustion furnace connected to the downstream end of the gas duct, wherein a different air injection nozzle is provided to the inside of the combustion furnace at the end of the horizontal gas duct , not on the upper and lower sides but on both left and right sides. Specially It proposes a molten combustion equipment to.

[0009]

The molten slag cooled and solidified at the outlet of the horizontal gas duct concentrates on the bottom and ceiling of the duct outlet.

The slag at the bottom is caused by gravity sedimentation, and the slag at the ceiling is caused by centrifugal force when the flow path of the combustion gas is changed from the outlet of the vertical gas duct to the horizontal gas duct into an L-shape. It is due to. Therefore outlet sides of the lateral duct is an area where the molten slag does not adhere, the outlet rather than upper and lower outlet in the present invention
Since the air injection nozzle is arranged in this area on both the left and right sides of the nozzle, the front surface of the nozzle is not covered with the molten slag cooled and solidified.

[0011]

FIG. 1 is a front view of an outlet of a horizontal gas duct (9) according to an embodiment of the present invention, as viewed from the inside of a boiler furnace as a combustion furnace. In this embodiment, tertiary air injection nozzles (12) are provided on both sides of the end of the horizontal gas duct (9) toward the inside of the boiler furnace. That is, the present embodiment differs from the conventional example in that the tertiary air injection nozzles (12) for secondary combustion are provided not on the upper and lower sides of the outlet of the horizontal gas duct (9) but on both left and right sides. is there. The other points are the same as those of the above-described conventional example, and the detailed description is omitted.

As described above, since the molten slag does not adhere to both sides of the outlet of the horizontal gas duct (9), the tertiary air injection nozzle (12) of this embodiment does not have to be covered with the molten and solidified molten slag. .

[0013]

According to the present invention, the secondary combustion burner using a carry-over slug is provided by arranging the air injection nozzles for secondary combustion on the left and right sides instead of vertically at the end of the horizontal gas duct. Slag trouble can be prevented.

[Brief description of the drawings]

FIG. 1 is a front view of an outlet of a horizontal gas duct according to one embodiment of the present invention as viewed from the inside of a boiler furnace as a combustion furnace.

FIG. 2 is a schematic longitudinal sectional view showing an example of a conventional melting and burning facility.

FIG. 3 is a view taken in the direction of arrows III-III in FIG. 2;

[Explanation of symbols]

 (1) Main combustor (2) Throat (3) Fuel injection nozzle (4) Secondary air injection nozzle (5) Subcombustor (6) Slag tap (7) Slag bin (8) Vertical gas duct (9) Horizontal gas duct (10) Combustion furnace (boiler furnace) (11), (12) Tertiary air injection nozzle

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Akiyasu Okamoto 5-717-1 Fukahori-cho, Nagasaki-shi Mitsubishi Heavy Industries, Ltd. Nagasaki Laboratory (56) References JP-A-2-126005 (JP, A) Japanese Unexamined Patent Publication (Kokai) Hei 3-79005 (JP, A) Japanese Unexamined Patent Publication (Kokai) No. 54-84630 (JP, A) Japanese Unexamined Patent Publication (Kokai) No. 52-84859 (JP, A) Japanese Unexamined Utility Model Publication No. 6-6929 (JP, U) JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F23J 1/00 F23G 5/32

Claims (1)

(57) [Claims] 1. A main cylinder having a substantially vertical cylindrical shape, a lower end narrowed down in a funnel shape to form a throat, and a fuel injection nozzle oriented in an axial direction and an air injection nozzle oriented in a tangential direction in an upper part. A combustor and a cylindrical shape whose axis is inclined with respect to the horizontal. The lower end of the throat is connected to the high end,
And a sub-combustor having a slag discharge port at a low position end, a vertical gas duct having a lower end connected to the low position end,
In those with a lateral gas duct upstream end connected to the upper end of the gas duct of the vertical, and a combustion furnace connected to the downstream end of the transverse duct, the left and right rather than up and down at the end of the lateral duct Melt combustion equipment characterized in that different air injection nozzles are provided on both sides toward the inside of the combustion furnace.