JPH073131Y2 - Coal burner - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a coal-fired MHD power generation (Magnetohydrodynamic Pow).
er Generation) for a coal combustor, and can be applied to a coal gasifier and a coal-fired gas turbine combustor.

[Conventional technology]

FIG. 3 is a schematic vertical sectional view showing an example of a conventional cyclone type coal combustor. In this figure, (1) is a horizontal cylindrical first combustion chamber, (2) is a coal injection nozzle provided on one end face (head) of the first combustion chamber (1), and (3) is A cyclone nozzle that is provided on the cylindrical side surface (body) of the first combustion chamber (1) and supplies an oxidant in a tangential direction along the inner wall surface, and (4) is the other end surface of the first combustion chamber (1). Is a partition wall through which the combustion gas outlet (4a) penetrates at the center. Further, (5) is a slag outlet provided in the lower part of the first combustion chamber (1) near the barrel partition (4), and (6) is a slag pot arranged therebelow. Further, (7) is a second combustion chamber provided outside the partition wall (downstream in the combustion gas flow direction) and supplied with an oxidant. Each of the vessel walls of the first combustion chamber (1) and the second combustion chamber (7) has a double wall structure forming a cooling water channel, and a refractory material is partially lined on the inner surface of the vessel wall. .

The pulverized coal fuel (8) injected from the coal injection nozzle (2) at the head of the first combustion chamber (1) is a cyclone nozzle (3).
The oxidant (oxygen or high temperature air) (9) blown from is mixed and diffused by the strong swirling flow of the oxidant and burned. The coal ash (slag) (10) generated by the combustion reaction is separated to the wall surface by the centrifugal force accompanying the swirling of the air flow, and the partition wall (4) at the rear part is blocked, and is provided in the lower part of the first combustion chamber (1). The slag outflow port (5) is allowed to flow down to the slag pot (6) and is extracted out of the system. On the other hand, the high temperature combustion gas from which the coal slag has been removed is guided to the second combustion chamber (7) through the combustion gas outlet (4a) provided in the central portion of the partition wall (4). The oxidizer (9) is also supplied to the second combustion chamber (7), and becomes a hotter gas to be discharged.

As is well known, the main component of coal ash is silica, and silica vaporizes at about 2000 ° C to become a gas. (Melting point is about 1400
C). Therefore, in order to separate the coal ash in the combustion chamber, the temperature of the combustion flame must be suppressed below about 1800 ° C. On the other hand, in MHD power generation, the temperature of the combustion gas plasma is 2000 to 2700 ° C. Therefore, as described above, the two-stage combustion system is used for the coal combustor, and the first combustion chamber (1)
In, the fuel is overburned at low temperature to remove slag,
In the second combustion chamber (7), a new oxidant is added to produce high temperature combustion plasma.

[Problems to be solved by the device]

The size of the first combustion chamber (1) in a practical-scale power generation plant (heat input of 100 MW or more) has a body diameter D of 1500 mm to 20 mm.
It is very big, 00 mm. In a practical machine, high temperature clean gas must be produced and supplied by removing coal ash (slag) in the coal combustor, which is a topping component of a plant, with a removal rate as high as possible. Generally, as a practical condition, in order to eliminate the harmful effects (degradation of performance, corrosion, wear) caused by the slag adhering to the inner wall of the gas passage of the equipment disposed downstream, the slag removal rate in the combustion chamber is 90% or more.
The above is required.

However, in the conventional coal combustor shown in FIG. 3, when the diameter D of the combustion chamber is large, it is necessary to increase the throttle diameter d of the combustion gas outlet (4a) provided in the partition wall (4). . This is because the flow pattern in the combustor changes depending on the ratio of D and d, and it is necessary to keep the ratio of D and d within a certain range in order to obtain a flow pattern that optimizes combustion performance. Diameter d of combustion gas outlet (4a)
Is large, this combustion gas outlet (4a) is
The slag (10) in the combustion gas accompanies the combustion chamber (7), and the carry-over ratio increases, and the slag removal rate in the first combustion chamber (1) decreases and the reliability is impaired. was there.

[Means for Solving the Problems]

In order to solve the above-mentioned conventional problems, the present invention provides a horizontal cylindrical first combustion chamber, a coal injection nozzle provided on one end surface of the first combustion chamber, and a cylinder of the first combustion chamber. A cyclone nozzle that is provided on a side surface and supplies an oxidant in a tangential direction, a first partition wall that closes the other end surface of the first combustion chamber and has a combustion gas outlet opening in the central portion, and the first partition wall near the first partition wall 1
The slag outlet provided in the lower part of the combustion chamber, the slag pot provided in communication with the slag outlet below the slag outlet, and the first partition wall provided outside the first partition wall with a space therebetween. A second partition wall that forms a straightening chamber between which a plurality of straightening holes penetrate, a second combustion chamber that is provided outside the second partitioning wall, and is supplied with an oxidizer; The present invention proposes a coal combustor characterized by including a slag downflow passage communicating with a pot.

[Action]

Most of the slag generated by the incomplete combustion of coal in the first combustion chamber is separated by the centrifugal force accompanying the swirling of the air flow,
It is blocked by the first partition wall and flows down from the slag outlet to the slag pot. The remaining slag flows into the rectification chamber, where it is separated into wall surfaces by the swirling flow as in the first combustion chamber, and is guided to the slag pot through the slag flow passage. The swirl of the air flow disappears at the second partition. The incompletely combusted gas is completely combusted by the newly supplied oxidant in the second combustion chamber to become a higher temperature gas.

〔Example〕

1 is a schematic vertical sectional view showing an embodiment of the present invention, and FIG. 2 is a horizontal sectional view taken along the line II-II of FIG. In these figures, the same parts as those of the conventional one described in FIG. 3 are given the same reference numerals to avoid redundancy, and detailed description thereof is omitted.

In this embodiment, the partition wall has a double structure, and the second partition wall is spaced outside the first partition wall (11) similar to the partition wall (4) in FIG. 3 (downstream of the combustion gas flow direction). (12) is provided, and the rectifying chamber (13) is formed between the first partition wall (11) and the second partition wall (12), and further downstream of the second partition wall (12) as in FIG. Second combustion chamber (7) is provided. The first partition wall (11) is provided with a combustion gas outlet (11a) in the central portion as described above, and the second partition wall (12) is provided with a plurality of rectifying holes (12a) penetrating the central partition portion. Also straightening chamber (13)
A slag flow-down passage (14) that communicates with the slag pot (6) from below the first partition wall (11) is provided.

In this embodiment, in order to enhance the action of separating the combustion residue (slag) in the first combustion chamber (1) and to accelerate the combustion of the fuel, the oxidant is supplied from the cyclone nozzle (3) at a flow rate of several hundred tens m / s. Blow at a swirling speed to form a powerful swirling vortex as shown by the solid arrow in FIG. This vortex flow continues through the combustion gas outlet (11a) to the flow regulating chamber (13) behind the first partition (11). In the first combustion chamber (1), the slag mist in the combustion flame is struck against the wall surface by the swirling airflow as indicated by the streamline of the dotted arrow, and flows in the wake along the wall surface to the first partition wall. Blocked at (11),
It flows down from the lower slag outlet (5) to the slag pot (6). From the weir of the first partition (11) to the combustion gas outlet (11
The slag mist that has overflowed and carried over through a) is separated into the wall surface in the same manner as above by the vortex flow in the flow control chamber (13).
It flows down from the slag flow passage (14) to the slag pot (6). On the other hand, in the second partition wall (12), the gas passage (rectifying hole)
Since the (12a) is dispersedly provided so as to avoid the central portion, the swirling vortex flow of the mainstream gas collides with the second partition wall (12) and is erased. Thus, 70 to 80% of the molten slag separated in the first combustion chamber (1) is collected in the first partition wall (11),
The remaining slag, which is entrained in the swirling vortex and overflows into the rectifying chamber (13), also collides with the second partition wall (12) and is adhered and collected on the wall surface, so that almost 100% slag removal performance is obtained.

[Effect of device]

According to the present invention, the slag generated by the combustion of coal can be almost completely separated and removed, which greatly contributes to the practical application of a large machine.

[Brief description of drawings]

1 is a schematic vertical sectional view showing an embodiment of the present invention, and FIG. 2 is a horizontal sectional view taken along the line II-II of FIG. FIG. 3 is a schematic vertical sectional view showing an example of a conventional coal combustor. (1) …… First combustion chamber, (2) …… Coal injection nozzle,
(3) …… Cyclone nozzle, (4) …… Partition wall, (4a)
...... Combustion gas outlet, (5) …… Slag outlet, (6)
…… Slag pot, (7) …… Second combustion chamber, (8) ……
Pulverized coal fuel, (9) …… oxidizer, (10) …… coal ash (slag), (11) …… first partition, (11a) …… combustion gas outlet, (12) …… second partition , (12a) …… Baffle hole, (1
3) rectifying chamber, (14) slag downflow passage.

Claims (1)

[Scope of utility model registration request] 1. A horizontally-arranged cylindrical first combustion chamber, a coal injection nozzle provided at one end face of the first combustion chamber, and a tangential direction oxidation provided at a cylindrical side face of the first combustion chamber. A cyclone nozzle for supplying the agent, a first partition wall that closes the other end surface of the first combustion chamber and has a combustion gas outlet opening in the center,
A slag outlet provided in the lower part of the first combustion chamber near the partition wall, a slag pot provided under the slag outlet in communication with the slag outlet, and a space provided outside the first partition wall. A second partition wall, which forms a straightening chamber between the first partition wall and a plurality of straightening holes, and a second combustion chamber which is provided outside the second partition wall and is supplied with an oxidant; A slag flow-down passage that connects the lower part of the chamber to the slag pot, and a coal combustor.