JP2008032362A - Combustion method for high moisture charcoal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combustion method for high moisture charcoal, adjusting the concentration of unburned combustibles in ash and the NO<SB>X</SB>concentration in burning powdered coal of high moisture charcoal by use of the existing equipment without requiring a large amount of money for investment in equipment expansion. <P>SOLUTION: According to this combustion method for high moisture charcoal, the supply amount of air to be mixed in burning powdered coal of the high moisture coal is adjusted according to the water content in powdered coal of the high moisture charcoal to adjust the concentration of unburned combustibles in ash and the NO<SB>X</SB>concentration. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for burning coal containing a large amount of water, and more particularly to a method for burning pulverized coal of high moisture coal.

  Coal is widely distributed around the world, has abundant recoverable reserves, and is inexpensive, so its importance is increasing as a long-term energy source. Currently, in Japan's electricity business, the calorific value as an energy source is as high as 25 MJ / kg (6,000 kcal / kg) to 30 MJ / kg (7,000 kcal / kg), and the fuel ratio (the fixed carbon content of coal is volatile). The bituminous coal with good combustibility is used, which is a value obtained by dividing by 1 to 2.5. However, considering the future increase in energy demand mainly in developing countries and the supply capacity of coal exporting countries, the supply of bituminous coal currently in use is expected to be tight.

  Therefore, it is important to use low-grade coal (such as sub-bituminous coal and lignite) that has a high moisture and ash content and a low calorific value. Among such low-grade coals, subbituminous coal has the largest reserves after bituminous coal, is widely distributed in the world, and is inexpensive, so it is expected as a promising energy source in the future.

However, subbituminous coal contains a lot of moisture, so its ignitability is poor, it is difficult to reduce NO _x generated when it burns, and the ash content is low even with the same combustion efficiency, so in ash There was a problem that the unburned component concentration was high.

To solve such a problem, for example, by extracting the combustion exhaust gas passing through the center part in the furnace width direction of the exhaust gas outlet part and recirculating it to the combustion part, NO _X in the combustion exhaust gas is increased without increasing the amount of recirculation gas. the recirculated efficiently combustion section, a method for reducing the emissions of the NO _X has been proposed (e.g., see Patent Document 1).

JP 2003-56810 A

  However, the above-described method has a problem that equipment such as a boiler has to be remodeled significantly and a large amount of capital investment is required.

In view of the above-mentioned circumstances, the present invention does not require a large amount of capital investment, and even if existing facilities are used, the unburned ash concentration and NO _x concentration when pulverized coal of high-moisture coal is burned. It aims at providing the combustion method of the high moisture coal which can be adjusted.

The present inventor has found that the unburned ash concentration and NO _x concentration can be adjusted by controlling the air supplied to the furnace together with the pulverized coal, through research on the pulverized coal of the high moisture coal, and reached the present invention. Here, high-moisture coal is not only a single type of coal that contains a large amount of moisture inside, such as bituminous coal or sub-bituminous coal, but also a mixture of multiple high-moisture coals with different moisture content. In particular, a blend of bituminous coal and subbituminous coal having a mass ratio of 9: 1 to 6: 4 is preferable.

According to a first aspect of the present invention for solving the above problems, the supply amount of air to be mixed when the pulverized coal of high moisture coal is burned is adjusted according to the amount of moisture contained in the pulverized coal of high moisture coal. in the combustion process of high moisture coal, characterized in that adjusting the unburned concentration and NO _X concentrations in ash Te.

In the first aspect, it is possible to adjust the concentration of unburned ash in the ash and the NO _x concentration that are generated when pulverized coal of high moisture coal is burned. Here, the pulverized coal refers to coal composed of particles having an average value (D50) of a minor axis and a major axis at an accumulated mass of 50% of about 40 μm.

  According to a second aspect of the present invention, in the method for burning high-moisture coal according to the first aspect, the swirl angle of the air swirling around an axis of a flame column generated by burning the pulverized coal of the high-moisture coal. It is in the combustion method of high moisture coal characterized by adjusting.

In the second aspect, it is possible to specifically adjust the unburned ash concentration and NO _x concentration generated when pulverized coal of high moisture coal is burned.

  According to a third aspect of the present invention, in the high moisture coal combustion method according to the first or second aspect, high moisture is introduced into the combustion atmosphere of the pulverized coal of the high moisture coal. It is in the combustion method of charcoal.

In the third aspect, it is possible to adjust the ash in unburned concentration and NO _X concentration generated when burning pulverized coal of a high moisture coal more detail.

  According to a fourth aspect of the present invention, there is provided the high moisture coal combustion method according to the third aspect, wherein the injection position for injecting the multistage air is adjusted.

In the fourth aspect, it is possible to adjust the unburned ash concentration and the NO _x concentration generated when the pulverized coal of high moisture coal is burned in more detail.

  According to a fifth aspect of the present invention, in the high moisture coal combustion method according to the third or fourth aspect, the high moisture coal combustion method is characterized by adjusting an injection ratio of the multistage air.

In the fifth aspect, it is possible to adjust the ash in unburned concentration and NO _X concentration generated when burning pulverized coal of a high moisture coal more detail.

  A sixth aspect of the present invention is the high moisture coal combustion method according to any one of the first to fifth aspects, wherein the flow rate of the air is adjusted.

In the sixth aspect, it is possible to adjust the ash in unburned concentration and NO _X concentration generated when further burning pulverized coal of a high moisture coal detail.

  According to a seventh aspect of the present invention, in the high moisture coal combustion method according to any one of the first to sixth aspects, the high moisture coal is a mixed coal composed of bituminous coal and subbituminous coal. It is in the combustion method of moisture coal.

  In the seventh aspect, the same effect as described above can be obtained.

According to the combustion method of the high moisture coal according to the present invention, an effect that it is possible to adjust the ash in unburned concentration and concentration of NO _X upon combustion of pulverized coal of a high moisture coal.

  Hereinafter, the best mode for carrying out the present invention will be described. The description of the present embodiment is an exemplification, and the present invention is not limited to the following description.

(Embodiment 1)
FIG. 1 is a schematic system diagram showing an example of a pulverized coal combustion apparatus for carrying out a method for burning high moisture coal according to Embodiment 1 of the present invention. As shown in FIG. 1, the pulverized coal combustion apparatus 1 has a cylindrical furnace 2, and a burner 3 is provided at one end of the furnace 2. The burner 3 is connected to a pulverized coal passage 8 connected to a pump 5, a steam generator 6, and pulverized bins 7a and 7b in which pulverized coal is stored. Secondary air) The pulverized coal is sent out to the furnace 2 together with the secondary air and the tertiary air so that the pulverized coal can be burned.

  A multi-stage combustion air injection port 4 connected to the pump 5 via an air pipe 43 is provided on the side surface of the furnace 2. The multi-stage combustion air injection port 4 includes a plurality of air injection ports 4 a to 4 n provided in parallel in the axial direction of the furnace 2. Each of the air injection ports 4a to 4n includes two air ports 41 facing each other and an air valve 44 that adjusts the amount of multistage air injected from the air port 41 into the furnace 2, respectively. 44 is adjusted so that the multistage air injection position and the multistage air amount supplied to the furnace 2 from the injection position can be controlled. Here, introducing multistage air into the combustion atmosphere of pulverized coal by the multistage combustion air injection port 4 is called multistage combustion, and the ratio of the total multistage air amount to the total air amount fed into the furnace 2 is defined as the multistage combustion rate. Here, the multistage air here refers to air that is injected into the furnace 2 from the plurality of air injection ports shown in FIG. 1, and each multistage air amount injected from each air injection port 4 corresponds to each air valve 44. It is adjusted by.

  Further, the other end of the furnace 2 is connected to a gas cooler 10, a multi-cyclone 11, a bag filter 12, a pump 13, and a discharge pipe 9 connected to the chimney 14. The combustion gas discharged from the furnace 2 is After the temperature is adjusted and the temperature is adjusted, the combustion ash contained in the multi-cyclone 11 and the bag filter 12 is removed and finally discharged from the chimney 14 to the outside air.

  In this way, the pulverized coal discharged from the pulverized bins 7a and 7b passes through the pulverized coal passage 8 together with the air for conveyance, and is sent into the furnace 2 from the burner 3. At the same time, a predetermined amount of multistage air is injected into the furnace 2 from a predetermined position (air injection port). As a result, the pulverized coal is completely burned in the furnace 2. Eventually, the pulverized coal burned in the furnace 2 becomes combustion ash and is discharged from the discharge pipe 9.

  Next, the burner 3 will be described. Although it will not specifically limit if it is a burner for coal combustion as the burner 3, A CI- (alpha) * WR burner is demonstrated as an example. FIG. 2 is a schematic cross-sectional view of the burner 3, and FIG. 3 is a schematic front view showing only the swirl vanes of the burner 3 when viewed from the direction A shown in FIG. As shown in FIG. 2, the burner 3 includes a primary air pipe 30, a secondary air inlet 31, and a tertiary air inlet 32 connected to the pulverized coal passage 8. The burner 3 is further provided with an oil burner 37 for igniting the burner.

  The primary air pipe 30 has a double pipe structure composed of an outer pipe 34 and an inner pipe 33 provided therein, and passes through the space between the inner pipe 33 and the outer pipe 34 to make fine powder. Primary air containing charcoal can be supplied to the furnace 2. Further, as shown in FIGS. 2 and 3, the secondary air swirling blade 311 and the tertiary air swirling blade 321 are provided at the secondary air introducing port 31 and the tertiary air introducing port 32, respectively. A plurality of secondary air inlets 32 are attached. And by adjusting these secondary air swirl vanes 311 and tertiary air swirl vanes 321, the swirl angles can be controlled in a wide range together with the flow rates of the secondary air and the tertiary air. Yes. Here, as shown in FIG. 4, the swirl angle refers to the inclination angle θ of the swirl blade 311 with respect to the central axis 21 of the furnace 2. It becomes equal to the inclination angle with respect to the axis. Therefore, no swirl flow occurs when the swivel angle is 0 degree (deg). And the pulverized coal is burned in the furnace 2 as shown below using the burner 3 comprised in this way.

  First, the pulverized coal that has passed through the pulverized coal passage 8 is fed into the furnace 2 through the primary air pipe 30 together with the carrier air (primary air). The pulverized coal sent to the furnace 2 is combusted with the primary air and the secondary air and the tertiary air sent as a swirling flow from the secondary air inlet 31 and the tertiary air inlet 32. The swirling directions of the secondary air and the tertiary air sent into the furnace 2 as swirling flow may be clockwise or counterclockwise, swirling in the same direction, or mutually You may turn in different directions. In the following experiment, both the secondary air and the tertiary air are swung counterclockwise.

  Next, the high moisture coal combustion method according to the present embodiment will be described using the pulverized coal combustion apparatus 1 described above.

<Combustion method of high-moisture coal that adjusts the amount of air for supplying burners>
Combustion method for high moisture coal according to the present embodiment is intended that by adjusting the supply amount of air mixed in the combustion of pulverized coal of a high moisture coal to adjust the unburned concentration and NO _X concentrations in ash is there. And the combustion method of the high moisture coal which concerns on this embodiment, specifically, the primary air amount supplied to the furnace 2 from the burner 3 mentioned above according to the moisture content contained in the pulverized coal of the high moisture coal adjust, it is that pulverized coal of a high moisture coal to adjust the ash in unburned concentration and NO _X concentration generated when burned.

Fig. 5 shows the amount of air transported when using a mixture of a mixture of Indonesian Adaro coal (sub-bituminous coal) and Australian Mount Asa coal (bituminous coal) in a ratio of 3: 7. Relationship between (primary air amount) and NO _x concentration (converted to O ₂ 6%) at the furnace 2 outlet and unburned ash concentration obtained by the bag filter 12 (coal input heat amount: 760 kW [low heat generation It corresponds to the amount of heat when charging 27.4 MJ / kg of design coal at 100 kg / h]. Here, (Air + H ₂ O) / Coal in FIG. 5 indicates a mass ratio of gas to pulverized coal considering that water (H ₂ O) contained in pulverized coal is vaporized.

In this experiment, two-stage multistage combustion in which multistage air was injected from injection position 1 and injection position 2 (see Table 1) was performed. Further, in this experiment, it was set when using the mount Arthur charcoal Australian as bituminous coal, the most suitable conditions shown in Table 1 in reducing of the NO _X concentration and the ash in the unburned concentration as a reference condition, this reference The primary air amount which is the amount of air for conveyance was changed from the conditions.

  Further, Table 2 shows the properties of Adaro coal and Mount Arta coal used in this experiment. Here, the air ratio in Table 2 is a value obtained by dividing the amount of air actually supplied to the burner by the amount of air (theoretical air amount) required to completely burn coal (pulverized coal). Further, the injection ratio of the multistage combustion air to the injection position 1 and the injection ratio of the multistage combustion air to the injection position 2 are the ratios of the respective multistage air amounts to the total air amount fed into the furnace 2. In total, the multistage combustion rate is obtained.

As shown in FIG. 5, it was found that as the value of (Air + H ₂ O) / Coal decreases, the NO _x concentration increases and the unburned ash concentration decreases. This is because, by reducing the amount of air for conveyance, the time for the pulverized coal to stay in the vicinity of the flame of the burner 3 increases, so that the pulverized coal burns and the unburned ash concentration decreases while the pulverized coal decreases. There is believed to be because the NO _X occurs mostly in more combustion.

On the other hand, it was found that as the value of (Air + H ₂ O) / Coal increases, the NO _x concentration decreases and the unburned ash concentration increases. This is also considered to be due to the reason described above.

In the region where the value of (Air + H ₂ O) / Coal is smaller than 1.9, pulverized coal accumulates in the pulverized coal passage 8 and in the region where the value of (Air + H ₂ O) / Coal is larger than 2.2. Since the flame of the burner 3 is blown off, the value of (Air + H ₂ O) / Coal can be set in the range of 1.9 to 2.2, and the range of 1.9 to 1.97 is preferable.

Thus, according to the high moisture coal combustion method according to the present embodiment, the amount of unmixed ash in the ash and the NO _x concentration are adjusted by adjusting the amount of air to be mixed when burning the pulverized coal of the high moisture coal. Can be adjusted.

<Combustion method of high-moisture coal that adjusts the swirl angle of the burner supply air>
The combustion method of the high moisture coal according to the present embodiment adjusts the swirl angle of the air swirling around the axis of the flame column generated by the combustion of the pulverized coal of the high moisture coal (swirling flow), and the unburned content in the ash is that adjusting the concentration and NO _X concentrations. The combustion method of high moisture coal according to the present embodiment, specifically, is that by adjusting the turning angle of the secondary air to adjust the unburned concentration and NO _X concentration in the ash. The turning direction of the secondary air may be clockwise or counterclockwise.

FIG. 6 shows the relationship between the secondary air swirl angle, the NO _x concentration (converted to O ₂ 6%) at the furnace 2 outlet, and the unburned ash concentration obtained by the bag filter 12. In this experiment, the swirl angle of the secondary air was changed in the combustion state where the value of (Air + H ₂ O) / Coal in FIG. 5 was 1.9.

As shown in FIG. 6, as the swirl angle of the secondary air increases, both the unburned ash concentration and the NO _x concentration in the ash once decrease, but when the swirl angle of the secondary air exceeds 63 degrees (deg). unburned concentration and NO _X concentration in the ash was found to increase together. This is considered to be because when the swirl angle of the secondary air is around 63 degrees, the pulverized coal is appropriately dispersed and a flame column suitable for burning the pulverized coal is formed. When the swirl angle of the secondary air becomes smaller than around 63 degrees, the straightness of the pulverized coal from the burner 3 toward the other end side of the furnace 2 becomes stronger, so that the pulverized coal is not burned sufficiently and is not burned sufficiently. This is thought to be because the NO _x generated by the combustion of pulverized coal moves away from the flame column without being sufficiently reduced in the vicinity of the flame column. On the other hand, when the swirl angle of the secondary air becomes larger than around 63 degrees, the swirl flow of the secondary air is too large and the pulverized coal diffuses in the radial direction of the flame column, and the pulverized coal does not burn sufficiently and the flame This is considered to be because the NO _x generated by the combustion of the pulverized coal moves away from the flame column without being sufficiently reduced in the vicinity of the flame column.

As described above, according to the high moisture coal combustion method according to the present embodiment, the swirl angle of the air swirling around the axis of the flame column generated by the combustion of the pulverized coal of the high moisture coal is adjusted so that it can be adjusted燃分concentration and NO _X concentrations.

In this experiment, was adjusted unburned concentration and NO _X concentration in the ash by adjusting the turning angle of the secondary air may be adjusted turning angle of the tertiary air. Even if the swirl angle of the tertiary air is adjusted, the unburned ash concentration and the NO _x concentration in the ash can be adjusted similarly.

<Combustion method of high moisture coal that adjusts the injection position of the multistage combustion air>
In the high moisture coal combustion method according to the present embodiment, when the high moisture coal pulverized coal is burned by multistage combustion, the injection position of the multistage air is adjusted to adjust the unburned ash concentration and the NO _x concentration. That's it. And the combustion method of the high moisture coal which concerns on this embodiment specifically adjusts the injection | pouring position of the 2nd step | paragraph multistage air inject | poured from the air injection port 4 for multistage combustion, and the unburned part concentration in ash And adjusting the NO _x concentration.

FIG. 7 shows the distance from the burner 3 to the second stage multi-stage air injection position, the NO _x concentration (converted to O ₂ 6%) at the furnace 2 outlet, and the unburned ash concentration obtained by the bag filter 12. Shows the relationship. In this experiment, the injection position of the second-stage multistage air was changed in the combustion state in which the swirl angle of the secondary air was 63 degrees in FIG. In addition, the injection ratio of the first multistage air amount and the second multistage air amount in this experiment was 50:50.

As shown in FIG. 7, it was found that as the distance from the burner 3 to the second stage injection position of the multistage air was decreased, the NO _x concentration increased and the unburned ash concentration decreased. This is considered to be because oxygen contained in the second multistage air is mainly consumed for the combustion of pulverized coal.

On the other hand, it was found that as the distance from the injection position of the multistage air injected from the burner 3 to the second stage was increased, the NO _x concentration decreased and the unburned ash concentration increased. This oxygen contained in the second stage of the multi-stage air not only the combustion of pulverized coal, is considered to be because it is consumed in the reduction reaction of NO _X.

Thus, according to the combustion method of high moisture coal according to the present embodiment, when burning high moisture coal pulverized coal in multistage combustion, the injection position of the multistage air is adjusted to adjust the unburned component concentration in ash and The NO _x concentration can be adjusted.

In this experiment, by adjusting the injection position of a multi-stage air to be injected to adjust the unburned concentration and NO _X concentration in the ashes on the second stage, the incident positions of the multi-stage air adjustment is limited to two-stage Absent. The incident position of the multistage air to be adjusted may be, for example, the injection position of the multistage air injected into the first stage, or the injection position of the multistage air injected into the n (n ≧ 3) stage, Furthermore, a plurality of multistage air injection positions may be used. Thus, even if the injection position of the multistage air is adjusted, the unburned ash concentration and the NO _x concentration can be adjusted similarly.

<Combustion method of high moisture coal that adjusts the injection ratio of the air for multistage combustion>
Combustion method for high moisture coal according to the present embodiment, the pulverized coal of a high moisture coal when combusted in staged combustion, the adjusted ashes in unburned concentration and NO _X concentrations injection ratio of the multi-stage combustion air It is to adjust. And the combustion method of the high moisture coal according to the present embodiment specifically adjusts the injection ratio of each multi-stage air injected from the multi-stage combustion air injection port 4, This is to adjust the NO _x concentration.

FIG. 8 shows the injection ratio of the multistage air injected into the first stage when performing the two-stage combustion, the NO _x concentration (O ₂ 6% conversion) at the furnace 2 outlet, and the ash obtained by the bag filter 12. The relationship with the unburned component concentration is shown. In this experiment, the injection ratio of each multi-stage air was changed in the combustion state where the injection position of the multi-stage air injected into the second stage in FIG. 7 was 5.39 m.

As shown in FIG. 8, it was found that the NO _x concentration decreased and the unburned ash concentration increased as the injection ratio of the multistage air injected into the first stage was decreased. This is considered to be because when the injection ratio of the multistage air injected into the first stage is reduced, the pulverized coal does not sufficiently burn because the oxygen contained in the multistage air is small.

On the other hand, it was found that as the injection ratio of the multistage air injected into the first stage was increased, the NO _x concentration increased and the unburned ash concentration decreased. This is because when the injection ratio of the multistage air injected into the first stage increases, the amount of oxygen contained in the multistage air increases and the pulverized coal burns sufficiently. This is presumably because the amount of oxygen contained in the multistage air to be injected decreases, and oxygen necessary for the NO _x reduction reaction becomes insufficient.

As described above, according to the high moisture coal combustion method according to the present embodiment, when the high moisture coal pulverized coal is burned in the multistage combustion, the injection ratio of the multistage combustion air is adjusted to reduce the unburned fraction in the ash. it is possible to adjust the concentration and NO _X concentrations.

In this experiment, the ash unburned component concentration and the NO _x concentration were adjusted by adjusting the injection ratio of each multi-stage air in the case of two-stage combustion. However, the present invention is not limited to this, for example, n (n ≧ 3) The injection ratio of each multistage air in combustion may be adjusted. Also in this case, similarly it is possible to adjust the unburned concentration and NO _X concentration in the ash.

The combustion method of each high moisture coal as described above can be applied to an existing coal boiler as it is. That is, if the high moisture coal combustion method according to the present invention is used, the existing coal boiler can be used as it is, and the unburned ash concentration and the NO _x concentration can be adjusted.

<Combustion method of high-moisture coal that adjusts the flow rate of burner supply air>
Combustion method for high moisture coal according to the present embodiment is that adjusting the flow rate adjusting in ash unburned concentration and NO _X concentrations of air to be mixed at the time of burning pulverized coal of a high moisture coal . And the combustion method of this high moisture coal which concerns on this embodiment specifically adjusts the flow velocity of the primary air supplied to the furnace 2 from the burner 3 mentioned above, and pulverized coal of high moisture coal burns. is that adjusting the ash in unburned concentration and NO _X concentration generated upon.

Figure 12 shows the ash in unburned concentration and concentration of NO _X upon combustion of pulverized coal is attached respectively to the burner 3 above the primary air pipe 9 to 11. In this experiment, the above-mentioned Indonesian Adaro coal, which is subbituminous coal, was used as the pulverized coal, and the pulverized coal was burned under the conditions shown in Table 3.

  Here, the primary air pipe 30A shown in FIG. 9 has a double pipe structure including an inner pipe 33A and an outer pipe 34A, and the inside of the space sandwiched between the inner pipe 33A and the outer pipe 34A is pulverized coal. And primary air flows (combustion condition A).

  The primary air pipe 30B shown in FIG. 10 has a double pipe structure similar to the primary air pipe 30A of FIG. 9, but the diameter of the inner pipe 33B is smaller than that of the primary air pipe 30A. Yes. Therefore, if the same amount of primary air as the primary air pipe 30A is caused to flow through the primary air pipe 30B, the flow velocity flowing into the furnace 2 becomes slower than when the primary air pipe 30A is used. (Combustion condition B).

  The primary air pipe 30C shown in FIG. 11 also has a double pipe structure like the primary air pipe 30A in FIG. 9, but the diameter of the inner pipe 33C is smaller than that of the primary air pipe 30A. Furthermore, a swirler 35 as a swirler and a rectifying plate 36 as a rectifier are provided between the inner tube 33C and the outer tube 34C. Therefore, when air containing pulverized coal flows through the primary air pipe 30C, a swirl flow is generated by the swirler 35, and the pulverized coal is concentrated on the inner wall surface side of the outer pipe 34C. Then, the swirling flow in which the pulverized coal is concentrated is rectified by the rectifying plate 36 and sent to the furnace 2 (combustion condition C).

As shown in FIG. 12, it was found that the NO _x concentration was reduced more when the primary air pipe 30B was used than when the primary air pipe 30A was used. That is, in this experiment, it was found that the NO _x concentration can be reduced by slowing the flow rate of the primary air.

In the case of using a primary air pipe 30C, it unburned concentration and NO _X concentrations in ash than the primary air pipe 30A and the primary air pipe 30B was found to be low. That is, in this experiment, concentrated pulverized coal, and by rectifying, it has been found that can both reduce the unburned concentration and NO _X concentration in the ash.

Thus, according to the combustion method of the high moisture coal according to the present embodiment, the flow rate adjusted in ash unburned concentration and NO _X concentrations of air to be mixed at the time of burning pulverized coal of a high moisture coal Can be adjusted.

1 is a schematic system diagram of a high moisture coal combustion apparatus according to Embodiment 1. FIG. It is a schematic sectional drawing of the burner which concerns on Embodiment 1. FIG. It is the schematic front view which showed only the swirl | wing blade of the burner at the time of seeing from the A direction shown in FIG. FIG. 3 is a schematic diagram illustrating a turning angle in the first embodiment. And conveying air amount in Embodiment 1 is a graph showing the relationship between the NO _X concentration and the ash in the unburned concentration. 2 is a graph showing the relationship between the secondary air swirl angle, the NO _x concentration, and the unburned ash concentration in Embodiment 1. 4 is a graph showing the relationship between the distance from the burner to the second stage injection position of multistage air in Embodiment 1, and the NO _x concentration and the unburned ash concentration in ash. 4 is a graph showing the relationship between the injection ratio of multistage air injected into the first stage in Embodiment 1, the NO _x concentration and the unburned ash concentration. It is a schematic sectional drawing which shows 30A of primary air pipes. It is a schematic sectional drawing which shows the primary air pipe 30B. It is a schematic sectional view showing a primary air pipe 30C. 2 is a graph showing the relationship between combustion conditions, NO _x concentration, and unburned ash concentration in Embodiment 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pulverized coal combustion apparatus 2 Furnace 3 Burner 4 Multi-stage combustion air injection port 5 Pump 6 Steam generator 7a, 7b Pulverized bottle 8 Pulverized coal passage 9 Exhaust pipe 10 Gas cooler 11 Multicyclone 12 Bag filter 13 Pump 14 Chimney 21 Center of furnace Shaft 30, 30A, 30B, 30C Primary air pipe 31 Secondary air inlet 32 Tertiary air inlet 33, 33A, 33B, 33C Inner pipe 34, 34A, 34B, 34C Outer pipe 35 Swirler 36 Rectifier plate 37 Oil burner 41 Air port 43 Air pipe 44 Air valve

Claims (7)

Depending on the amount of moisture contained in the pulverized coal of a high moisture coal, to adjust the adjusting in ash unburned concentration and NO _X concentrations supply amount of air to be mixed at the time of burning pulverized coal of the high moisture coal A method for burning high moisture coal. The high moisture coal combustion method according to claim 1,
A method for combusting high-moisture coal, characterized in that the swirl angle of the air swirling around an axis of a flame column generated by burning the high-moisture coal pulverized coal is adjusted. The high moisture coal combustion method according to claim 1 or 2,
A high moisture coal combustion method, wherein multistage air is introduced into the combustion atmosphere of the high moisture coal pulverized coal. In the method of burning high moisture coal according to claim 3,
A high moisture coal combustion method characterized by adjusting an injection position for injecting the multistage air. The high moisture coal combustion method according to claim 3 or 4,
A high moisture coal combustion method characterized by adjusting an injection ratio of the multistage air. In the combustion method of the high moisture coal in any one of Claims 1-5,
A method for burning high-moisture coal, wherein the flow rate of the air is adjusted. In the combustion method of the high moisture coal in any one of Claims 1-6,
The high moisture coal combustion method, wherein the high moisture coal is a mixed coal composed of bituminous coal and subbituminous coal.

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