JP2582419B2 - Melt combustion equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for melting and burning a fuel containing a non-combustible substance or a flame-retardant substance, and includes a coal-fired boiler, a sludge-fired boiler, and various waste combustion facilities. And so on.

[Conventional technology]

7 and 8 are longitudinal sectional views each showing an example of a conventional coal melting and burning apparatus, in which FIG.
The figure is an example of a vertical type. In these figures, 01 is a combustor, 02 is a fuel injection nozzle, 03 is a combustion air pipe, 04 is an air injection nozzle, 05 is a slag baffle, 06 is a slag tap,
07 denotes a slag bin, and 08 denotes a combustion gas outlet duct.

First, a horizontal coal melting and burning apparatus will be described. The fuel injected from the fuel injection nozzle 02 into the combustor 01 is provided with a swirling force by the combustion air injected tangentially from the air injection nozzle 04 and burns at high speed. The heat load in the combustor 01 is high, and the combustion residue is melted and applied to the peripheral wall by centrifugal force to flow down. The molten residue is separated by the slag baffle 05, passes through a cutout provided at the lower part of the slag baffle, falls through the slag tap 06, and falls on the slag pin 07. The combustion gas exits through the combustion gas output duct 08.

The vertical coal melting and burning apparatus is almost the same as the horizontal type, but is not separated by the slag baffle.

[Problems to be solved by the invention]

The horizontal melting and burning apparatus has the following problems.

(1) The separation mechanism is only the centrifugal separation mechanism in the combustor, and a sufficient separation function cannot be obtained.

(2) The molten residue adhering to the upper part of the slag baffle falls by gravity and re-scatters due to the high-speed gas flow in the slag baffle part.

(3) Since the molten residue accumulates at the bottom of the combustor and does not uniformly adhere to the entire circumference, a temperature difference occurs in the wall surface, and thermal stress is generated.

(4) The residence time required to complete the combustion of the combustibles in the molten residue cannot be sufficiently secured.

 In the case of the vertical type, there are the following problems.

(1) The residence time of the molten residue cannot be sufficiently secured.

(2) Heat loss in slag bin and evaporation of bottled water are large.

As described above, the conventional melt-burning apparatus, whether vertical or horizontal, has difficulty in separating and collecting the molten residue and completely producing the combustible components contained in the molten residue.

[Means for solving the problem]

The present invention proposes the following melt combustion apparatus in order to solve the above conventional problems.

(1) The cylinder has a vertical cylindrical axis, the lower end of which is conically narrowed to form a throat, and has an axially oriented fuel injection nozzle and a tangentially oriented secondary air injection nozzle at the top, A main combustor for performing gasification combustion, and a sub combustor having a cylindrical shape whose axis is inclined with respect to the horizontal, having a lower end connected to the lower end of the throat, and having a combustion gas outlet and a slag outlet at a lower end. A fusion combustion device comprising a combustor.

(2) The melting and burning apparatus according to the above (1), wherein a lower end of the throat is connected in a tangential direction of the sub-combustor.

(3) The melting and burning apparatus according to the above (1) or (2), wherein a slag baffle having a notch on a high position side of the sub-combustor is provided around the inlet of the throat.

[Action]

 The present invention is configured as described above and has the following operations.

(1) Since the main combustor has a cylindrical shape, that is, a vertical shape that is symmetrical with the axis, and the flows of the combustion gas and the molten residue are both directed downward, stable swirling combustion and prevention of swirling force attenuation are achieved.
High combustion efficiency and high separation and collection efficiency of the molten residue can be obtained. Further, the adhesion of the furnace residue to the furnace wall becomes uniform, the thermal stress is reduced, and the reliability is improved. Further, since the combustion gas and the molten residue flow in the same direction, the once separated molten slag does not re-scatter.

(2) Since the outlet of the main combustor is conically narrowed, the separation efficiency is further improved by increasing the centrifugal force.

(3) Since the horizontal sub-combustor is connected to the main combustor outlet, and the main combustor outlet gas is introduced at a high speed, the fine particles collide with the bottom of the sub-combustor and are collected and separated.

(4) Since the slag discharge port is provided at the outlet end of the sub-combustor, the residence time necessary for completing the combustion of the combustible components in the molten residue from the inlet to the outlet of the sub-combustor is secured,
The fuel can be completely burned.

(5) When the throat of the main combustion outlet is mounted in the tangential direction of the sub-combustor, a strong swirling flow is also established in the sub-combustor, and the fine molten residue floating in the combustion gas is captured by centrifugal force. Collected and separated.

(6) In the case where a slag baffle having a notch on the high position side of the sub-combustor, that is, on the side opposite to the direction in which the combustion gas flows in the sub-combustor, is provided around the inlet of the throat at the outlet of the main combustor. Since the molten residue flows down the notch, the molten slag collected in the main combustor is prevented from being scattered again.

〔Example〕

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, and FIG. 2 is a plan view taken along the line II-II of FIG. A fuel injection nozzle 2 is mounted on the upper part of a cylindrical and vertical main combustor 1, and pulverized coal is injected at a certain spread angle in the axial direction as a primary air-fuel mixture. On the other hand, the secondary air is supplied by a combustion air pipe 3 and is injected tangentially from an air injection nozzle 4 tangentially mounted on the upper part of the main combustor 1. The amount of air is maintained at a combustion rate such that the air ratio at the outlet of the main combustor is 1.0 or less, for example 0.7, so that the combustion field is in a reducing atmosphere and the temperature in the combustor is higher than the melting temperature of the pulverized coal-containing ash Controlled to the amount needed to do so. The main combustor has a heat insulating structure, and the temperature inside the combustor is maintained at a high temperature in combination with the effect of forming the heat insulating layer by the molten slag.

The pulverized coal that has been injected gasifies and burns at high temperatures while violently circling with the secondary air that has been injected into the tangential, and the combustible components are CO, CO ₂ , H ₂ , HC, H ₂ O, etc. Become. Then, it turns to the throat 9 at the exit while turning. On the other hand, the ash contained in the pulverized coal is melted, blown to the combustor wall by centrifugal force and collected, and forms a molten slag layer flowing down the wall. The pulverized coal having a large particle size is trapped by the molten slag on the peripheral wall in a state of incomplete combustion, but completes gasification combustion while flowing down. Since the outlet of the main combustor 1 is formed in a conical shape, the centrifugal force increases at the outlet, so that the fine particles in the combustion gas are also adhered and collected on the falling slag.

In this way, the first stage gasification combustion and coal ash melting and separation are performed in the main combustor 1, but finer molten ash still remains in the combustion gas, and the molten slag contains Although a very small amount of combustibles remain, they are completely removed and gasified in the next second stage (subcombustor).

The sub-combustor 10 has a cylindrical shape whose axis is slightly inclined with respect to the horizontal, and the lower end of the throat 9 is connected to a high position end (left side in the figure).

The slag flowing down the peripheral wall of the main combustor 1 flows down the throat 9 and falls to the bottom of the sub-combustor 10. Thus, a molten slag layer is formed at the bottom of the sub-combustor. Further, the fine slag contained in the combustion gas is composed of the main combustor throat 9
Is blown into the sub-combustor 10 at a high speed, so that an inertia force is applied to the sub-combustor 10 so that the inert gas collides with the slag layer at the bottom of the sub-combustor 10 and is attached and collected. As described above, the melt combustion apparatus according to the present embodiment has a two-stage separation function of slag separation: centrifugal separation in the main combustor and collision separation in the sub-combustor.

Next, unburned particles such as carbon may be contained in the molten slag at the outlet of the combustor 1, and this is because the molten slag slowly moves to the lower side (to the right in the figure) of the sub-combustor 10. While flowing, it reacts with oxygen, hydrogen or steam to gasify.
In this way, all combustible components in the slag are gasified.

A slag tap 6 is provided at a lower position end (right end in the figure) of the sub-combustor 10, so that the molten slag flows down to the slag bin 7 and is discharged. The clean combustion gas from which the molten slag has been removed is supplied from the combustion gas outlet duct 8 to the outside as high-temperature fuel.

FIG. 3 is a sectional side view showing a second embodiment of the present invention, and FIG. 4 is a plan view taken along the line IV-IV of FIG. In this embodiment, the lower end of the throat 9 at the outlet of the main combustor 1 is connected in the tangential direction of the sub-combustor 10. Therefore, the fine slag contained in the outlet gas of the main combustor 1 is further swirled in the sub-combustor 10 and centrifuged (two-stage centrifugation).

FIG. 5 is a vertical sectional side view showing the structure of the inlet of the throat 9 at the outlet of the main combustor in the third embodiment of the present invention, and FIG. 6 is a plan view taken along the line VI-VI of FIG. In this embodiment, a slag baffle 11 is provided around the entrance of the throat 9. The slag baffle 11 has a notch on the high position side (left side in the figure) of the sub-combustor 10. Therefore, when the molten slag flows down into the sub-combustion chamber 10, it flows down the throat 9 in a direction opposite to the gas flow direction (left side in the figure) and does not flow down in the main flow of the gas. The molten slag collected in the step is prevented from re-scattering into the gas stream.

〔The invention's effect〕

 According to the present invention, the following effects can be obtained.

(1) A vertical main combustor mainly composed of swirling combustion and a horizontal sub-combustor are joined and integrated, and a centrifugal separation function in the main combustor and a collision separation function in the sub-combustor inlet are provided.
Very high (more than 95%) slag separation function can be achieved.

(2) Since a sufficient residence time for the slag flow can be secured in the horizontal sub-combustor, the combustibles in the slag are completely gasified, and a high gasification combustion efficiency (99% or more) can be obtained. This is achieved by selecting the length of the sub-combustor so that the required slag residence time is obtained according to the gasification rate of combustibles in the slag.

(3) Even in the sub-combustion chamber, a very high slag separation efficiency can be achieved by providing a centrifugal separation function by a swirling flow in addition to the collision separation of (1).

(4) When the slag adhered to the peripheral wall of the main combustor and collected is allowed to flow down to the lower throat, the slag baffle guides the slag to flow down the side opposite to the gas flow of the throat. The falling slag does not cross the combustion gas at the inlet of the sub-combustor, and the slag can be prevented from re-scattering into the gas flow. Therefore, high slag collection efficiency can be maintained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, and FIG. 2 is a plan view taken along the line II-II of FIG. FIG. 3 shows the second embodiment of the present invention.
FIG. 4 is a plan view taken along the line IV-IV of FIG. FIG. 5 is a longitudinal sectional side view showing an inlet part structure of a main combustor outlet throat in a third embodiment of the present invention,
FIG. 6 is a plan view taken along the line VI-VI of FIG. 7 and 8 are longitudinal side views each showing an example of a conventional coal melting and burning apparatus. 01 ... combustor, 1 ... main combustor, 02,2 ... fuel injection nozzle, 03,3 ... combustion air pipe, 04,4 ... air injection nozzle, 05 ... slag baffle, 06,6 … Slag tap, 07,7… Slag bin, 08,8… Combustion gas outlet duct, 9… Main combustor throat, 10… Subcombustor, 11… Vertical slag baffle.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kimyoyo Tokuda 1-1, Akunouracho, Nagasaki-shi, Nagasaki Mitsubishi Heavy Industries, Ltd. Nagasaki Research Institute (72) Inventor Akiyasu Okamoto 1-1, Akunouracho, Nagasaki-shi, Nagasaki No. Mitsubishi Heavy Industries, Ltd. Nagasaki Laboratory (56) References JP-A-63-172808 (JP, A) JP-A-60-202208 (JP, A)

Claims (3)

(57) [Claims] An axial line is a vertical cylinder, a lower end thereof is conically narrowed to form a throat, and an upper part has a fuel injection nozzle oriented in an axial direction and a secondary air injection nozzle oriented in a tangential direction. The main combustor performing gasification combustion, and a cylindrical shape whose axis is inclined with respect to the horizontal, the lower end of the throat is connected to a high position end, and a combustion gas outlet and a slag discharge port are connected to a low position end. And a sub-combustor having the same. 2. The melting combustion apparatus according to claim 1, wherein a lower end of the throat is connected in a tangential direction of the sub-combustor. 3. The melting and burning apparatus according to claim 1, wherein a slag baffle having a notch on a high position side of the sub-combustor is provided around an inlet of the throat.