JP7285685B2 - Furnaces and boilers equipped therewith - Google Patents

Description

TECHNICAL FIELD The present invention relates to a furnace and a boiler having the same, and more particularly to a technology for removing ash adhering to furnace walls.

Since coal contains ash and sulfur content, sulfidation corrosion occurs on the furnace wall due to adhesion of ash generated by combustion to the furnace wall and hydrogen sulfide generated in the reducing atmosphere. In particular, when foreign low-grade coal or biomass containing a large amount of alkali and sulfur is used as fuel, the problem of frequent operational failures due to sulfidation corrosion and ash adhesion has become apparent.

The degree of sulfidation corrosion and the degree of ash adhesion are also affected by the structure of the furnace. The configuration of a conventional boiler will be described below with reference to FIGS. 7 and 8. FIG. 7 and 8, the vertical direction is represented by the z-axis, and the width direction and the depth direction orthogonal to each other in the horizontal plane are represented by the x-axis and the y-axis, respectively. Fig. 7 shows a conventional domestic boiler 700, Fig. 8 shows a boiler 900 with a wide furnace depth (in the y-axis direction) seen overseas, and Fig. 9 shows a boiler equipped with a water flow ash removal device and a wall blower. It is a diagram.

In the overseas boiler 900 with a wide furnace depth (see FIG. 8), the depth direction of the furnace 911 is wider than the domestic boiler 700 (see FIG. 7) (D2>D1), and the distance from the upper burner 921 to the after airport 939 Some boilers have a distance H2 greater than the domestic boiler 700 (H2>H1).

In general, the area of the furnace wall from the upper burners 721, 921 to the after-airports 739, 939 has a high heat load and is a strong reduction area. becomes a remarkable high potential region.

The high potential areas A1 and A2 can be expressed by A1=H1*D1 and A2=H2*D2. Therefore, the longer the distances H1, H2 from the upper burners 721, 921 to the after-air ports 739, 939 and the longer the depths D1, D2 of the furnaces 711, 911, the larger the high potential areas A2, A1. For this reason, the high potential region A2 of the boiler 900 of the overseas wide type boiler expands more than the high potential region A1 of the boiler 700 of the domestic market.

Since the high potential areas A2 and A1 have a high heat load, ash adhesion is severe, and installation of an ash removal device is indispensable in order to ensure the boiler performance. Therefore, conventionally, as an ash removal device, a water flow ash removal device 151, 152 (see FIG. 9A, Patent Document 1) that removes ash by spraying a water flow on the surface of the adhered ash, or an ash removal medium such as air or steam is installed on the side wall. Wall blowers 171, 172, 173, 174 are known that blow into the air to remove ash. In FIGS. 7, 8 and 9, dotted circles indicate areas of ash removal by the wall blowers 171, 172, 173 and 174, respectively.

U.S. Pat. No. 5,925,193

The features of the water flow ash removal devices 151, 152 are the wide range inside the furnaces 711, 911, specifically, the wide range from the bottom of the lower burner 723 to the after air port 739 as shown by the hatched area in FIG. 9(a). It is possible to remove even slag-like hard ash. In addition, since the water flow ash removal devices 151 and 152 use water flow, the steam and air blown against the water wall like a wall blower may involve the surrounding ash and collide with the side wall at high speed to cause erosion. There is an advantage that there is no

On the other hand, since the water flow ash removal devices 151 and 152 have a wide ash removal area in one cycle, the steam temperature fluctuation is large, and the operation of the water flow ash removal devices 151 and 152 has a large influence on the control of the boiler 700. Become. In addition, fluctuations in the exhaust gas temperature during operation of the water flow ash removal devices 151 and 152 are large, and this greatly affects the combustion performance (NOx, CO). Furthermore, by operating the water flow ash removal devices 151 and 152, a wide range of ash is removed at once, but the removed ash falls as a huge ash mass, and the bottom (hopper) of the furnace 711 and 911 is damaged. (see FIG. 9(a)).

On the other hand, the feature of the wall blowers 171, 172, 173, 174 is that the ash removal area at one time is narrower than the water flow ash removal devices 151, 152, so the steam temperature fluctuation is small, and as a result, the control of the boilers 700, 900 It has little impact on In addition, when the wall blowers 171, 172, 173, and 174 are operated, fluctuations in exhaust gas temperature are small, and there is little effect on combustion performance (NOx, CO). Further, by dividing into smaller sections and operating the wall blower regularly, it is possible to suppress the falling of huge ash lumps and prevent damage to the bottoms of the furnaces 711 and 911 (see FIG. 9(b)).

However, in the wall blowers 171, 172, 173, 174, slag-like ash is difficult to remove. Further, frequent ash removal is required in areas where ash adhesion is severe, such as high potential areas A1 and A2. Furthermore, the steam and air sprayed against the water wall provided with a plurality of heat transfer tubes installed on the side walls of the furnaces 711 and 911 entrain the surrounding ash and collide with the side walls at high speed to generate erosion.

Therefore, when attempting to remove the ash in the high potential areas A1 and A2 with a wall blower, erosion is caused, and the simultaneous occurrence of sulfidation corrosion and erosion accelerates the metal loss (hereinafter referred to as composite metal loss).

Therefore, in order to avoid composite thinning, it is necessary to perform thermal spraying, overlaying, etc. on the areas where the ash removal medium hits by the wall blowers 171, 172, 173, 174, which increases the initial cost and requires regular maintenance. In such cases, it affects the boiler inspection schedule.

As described above, ash removal devices have different merits and demerits depending on the type of ash removal device.

However, for the ash removal in the high potential regions A1 and A2, it is required to achieve both cost reduction and reduction of influence on boiler control and improvement of ash removal performance. In particular, the boiler 900, which has a wide depth, as is often seen in overseas boilers, has a high potential area A2 that is wider than the high potential area A1 of the boiler 700 in Japan. Removal techniques are needed.

The present invention is intended to solve the above-described problems, avoiding composite thinning, reducing the initial cost and maintenance cost of the boiler, shortening the regular inspection schedule, and securing the ash removal performance in the high potential region. The object is to provide a boiler with it.

In order to solve the above problems, the present invention has the configuration described in the claims. An example of this is a furnace that burns fuel in two stages by supplying air. A burner that is provided on the side wall and burns fuel with an air amount less than the theoretical air amount, and a burner that is installed vertically above the installation position of the burner on the side wall of the combustion cylinder and supplies secondary air for two-stage combustion. A water flow is injected into an after air port supplied into the combustion cylinder and a first height region from above the installation position of the burner on the side wall of the combustion cylinder to below the installation position of the after air port, a water stream ash removing device for removing ash adhering to a first height region; and a second height region above the installation position of the after air port on the side wall of the combustion cylinder, injecting steam or air into the second height region. and a wall blower for removing ash adhering to the height region.

According to another aspect of the present invention, there is provided a boiler including the above furnace.

According to the present invention, there is provided a furnace and a boiler equipped with the same that avoids complex thinning, reduces the initial boiler cost and maintenance cost, shortens the regular inspection schedule, and secures ash removal performance in the high potential region. can do. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

Schematic configuration diagram of a boiler according to the present embodiment External view of the furnace viewed from the front in the depth direction Side view of the furnace A diagram showing the installation position of the water flow ash removal device and the ash removal area (AA cross section in FIG. 3) A diagram showing another example of the installation position of the water flow ash removal device and the ash removal area (cross section AA in FIG. 3) A view showing the installation position of the water flow ash removal device (one on each side wall surface) and another example of the ash removal area (cross section AA in FIG. 3) A view showing the installation position of the water flow ash removal device (one on each side of a set of opposing faces) and another example of the ash removal area (cross section AA in FIG. 3) A diagram showing the installation position of the water flow ash removal device (one on each of the two adjacent surfaces) and another example of the ash removal area (cross section AA in FIG. 3) Diagram showing a conventional boiler Diagram showing a type of boiler with a wide furnace depth (y-axis direction) seen overseas A diagram of a boiler installed with a water flow ash removal device and a wall blower Diagram showing another example of burner installation position

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and repeated explanations are omitted.

FIG. 1 is a schematic configuration diagram of a boiler 10 according to this embodiment. The boiler 10 uses pulverized coal as a solid fuel. The boiler 10 is a coal-fired boiler capable of burning pulverized coal with the burners 21, 22, and 23 of the furnace 11 and heat-exchanging the heat generated by this combustion with water or steam to generate steam. The fuel is not limited to coal, and may be biomass, heavy oil, or other fuel that can be combusted in a boiler. Further, various kinds of fuels may be mixed and used.

The boiler 10 has a furnace 11 , a combustion device 12 and a flue 13 . The furnace 11 has, for example, a hollow square shape and is installed along the vertical direction. A side wall of the furnace 11 is composed of evaporating tubes (heat transfer tubes) and fins connecting the evaporating tubes. suppressing the rise. Specifically, on the side wall of the furnace 11, a plurality of evaporator tubes are arranged, for example, along the vertical direction and arranged side by side in the horizontal direction. The fins block the space between the evaporation tubes. The furnace 11 is provided with a hopper 62 at its bottom, and the hopper 62 is provided with a bottom evaporator 70 to form a bottom surface.

The combustion device 12 is provided on the vertically lower side of the furnace wall that constitutes the furnace 11 . In this embodiment, this combustion device 12 has a plurality of burners 21 , 22 , 23 mounted on the side walls of the furnace 11 . The shape of the furnace 11, the arrangement of burners, the number of burners in one stage, and the number of stages are not limited to those of this embodiment.

These burners 21 , 22 , 23 are connected to pulverizers (coal pulverizers/mills) 31 , 32 , 33 via pulverized coal supply pipes 26 , 27 , 28 . When coal is conveyed by a conveying system (not shown) and put into the pulverizers 31, 32, 33, it is pulverized to a predetermined fine powder size, and is fed into a pulverized coal supply pipe together with air for transportation (primary air). The burners 21 , 22 , 23 can be supplied with crushed coal (pulverized coal) from 26 , 27 , 28 .

Further, the furnace 11 is provided with a wind box 36 at the mounting position of each burner 21, 22, 23, and an air duct 37a for supplying air to the wind box 36 is connected.

A flue 13 is connected to the upper side of the furnace 11 in the vertical direction, and a plurality of heat exchangers (41, 42, 43, 44, 45, 46, 47) for generating steam in the flue 13. are placed. Therefore, the burners 21 , 22 , and 23 inject a mixture of pulverized coal fuel and combustion air into the furnace 11 to form a flame and generate combustion gas that flows into the flue 13 . The combustion gas heats feed water and steam flowing through the furnace wall and the heat exchangers (41 to 47) to generate superheated steam. Power can be generated by rotating a generator (not shown) connected to the rotating shaft of the turbine. Further, the flue 13 is connected to an exhaust gas passage 48, and is connected to a denitrification device 50 for purifying combustion gas. An air heater 49 for exchanging heat with the air heater 49, a dust processing device 51, an induced draft fan 52, etc. are provided, and a chimney 53 is provided at the downstream end. Note that the denitrification device 50 may not be provided if the exhaust gas standard can be satisfied.

In the furnace 11 of the present embodiment, after excessive fuel combustion by air for pulverized coal carrier (primary air) and combustion air (secondary air) introduced into the furnace 11 from the wind box 36, new combustion air ( It is a so-called two-stage combustion type furnace in which after-air is introduced to perform fuel-lean combustion. Therefore, the furnace 11 is provided with an after-airport 39 . One end of the air duct 37 b is connected to the after air port 39 and connected to the blower 38 via the air heater 49 .

FIG. 2 is an external view of the furnace 11 viewed from the front in the depth direction. FIG. 3 is an external view of the furnace 11 viewed from the side. 2 to 6, the vertical direction is represented by the z-axis, and the width direction (first horizontal direction) and depth direction (second horizontal direction) orthogonal to each other in the horizontal plane are represented by the x-axis and the y-axis, respectively.

The furnace 11 shown in FIG. 2 has a housing structure that is installed along the vertical direction with respect to the ground and surrounded by water-cooled walls made up of water-cooled pipes. A combustion space is formed inside the furnace 11 in which pulverized coal as fuel is burned. Combustion gas generated in the combustion space flows from the lower side to the upper side in the vertical direction of the furnace 11, as indicated by the thick arrow in FIG.

In the furnace 11, the vertically lower side is the "upstream side" of the combustion gas flow, and the vertically upper side is the "downstream side" of the combustion gas flow. Therefore, the outlet of the furnace 11 is located vertically above, downstream of the combustion gas flow.

A flue 13 extending in a direction crossing (perpendicular to) the furnace 11 is connected to the upper portion (exit) of the furnace 11 .

The furnace 11 includes a hopper 62 having an inclined surface, and a combustion cylinder 11A in the shape of a square cylinder above the hopper 62 in the vertical direction. In the following description, the four side walls of the combustion cylinder 11A are called a first side wall 110A, a second side wall 110B, a third side wall 110C (see FIG. 3), and a fourth side wall 110D. The first side wall 110A and the second side wall 110B are side walls of the furnace 11 arranged to face each other in the depth direction. Each of the third side wall 110C and the fourth side wall 110D is a side wall that connects the first side wall 110A and the second side wall 110B, and is arranged to face them in the width direction. In the xy plane, they are referred to clockwise as first sidewall 110A, third sidewall 110C, second sidewall 110B, and fourth sidewall 110D.

In each of the first side wall 110A and the second side wall 110B, 12 burners are arranged in three stages in the vertical direction, and four burners are arranged in each stage along the width direction. Burners 21 represent the four burners in the upper stage, burners 22 represent the four burners in the middle stage, and burners 23 represent the four burners in the lower stage. The upper burner 21, the middle burner 22, and the lower burner 23 on the side of the first side wall 110A and the side of the second side wall 110B are arranged to face each other, and have the same configuration.

In each of the first side wall 110A and the second side wall 110B, four after-air ports 39 are arranged in the width direction above the upper burner 21 and below the outlet of the furnace 11 in the vertical direction. The four after-air ports 39 on the side of the first side wall 110A and the four after-air ports 39 on the side of the second side wall 110B are arranged at positions facing each other and have the same configuration.

Note that the arrangement of the plurality of after-airports 39 of the furnace 11, the number in the vertical direction, and the number in the width direction are not necessarily limited to those illustrated.

Ash generated when the fuel is incinerated adheres to the side walls in the furnace 11 . Particularly in the combustion area, the area from the upper burner 21 to the after-air port 39 is a high potential area A3 where ash tends to adhere to the side wall of the furnace 11 .

Therefore, in the furnace 11 of the present embodiment, as shown in FIG. 3, water stream ash removal devices 151 and 152 are installed in the high potential areas A3 of the third side wall 110C and the fourth side wall 110D. Further, six wall blowers 171 and 172 are installed in two stages in the vertical direction and three in the depth direction in each region above the high potential region A3 of the third side wall 110C and the fourth side wall 110D. In the following description, the arrangement of the plurality of water ash removing devices 151, 152 and the plurality of wall blowers 171, 172 on the side wall of the furnace 11, the number in the vertical direction, the number in the width direction, and the number in the depth direction are as follows: Not limited to the examples

The upper wall blower 171 and the lower wall blower 172 on the side of the third side wall 110C are arranged at positions facing each other, and both have the same configuration.

In addition, in the third side wall 110C and the fourth side wall 110D, the nozzle directions of the water flow ash removal devices 151 and 152 are adjusted for the area from the upper burner 21 to the lower burner 23 where the ash tends to fall under its own weight, and the area below it. and may optionally be sprayed with water to remove ash.

With reference to FIGS. 4 to 6C, installation positions and ash removal areas of the water stream ash removal devices 151 and 152 will be described. 4, 5, 6A, 6B, and 6C are diagrams showing the installation positions and ash removal areas of the water flow ash removal devices 151 and 152, and are sectional views taken along the line AA in FIG.

As shown in FIG. 4, the third side wall 110C and the fourth side wall 110D are sprayed with water in the region from the upper stage burner 21 to the bottom of the after-airport 39, and the water flow removes the ash adhering to the side wall by the force of the water. The ash removing devices 151 and 152 are arranged one by one so as to face each other in the width direction.

The flowing ash removing device 151 on the side of the third side wall 110C and the flowing ash removing device 152 on the side of the fourth side wall 110D are arranged at positions facing each other, and both have the same configuration. The water stream ash removing device 151 on the side of the third side wall 110C injects a water stream (indicated by an arrow) into the high potential area A3 of the fourth side wall 110D. The water stream ash removing device 152 on the side of the fourth side wall 110D injects water into the high potential area A3 of the third side wall 110C.

FIG. 5 is another example of installation of the water stream ash removing devices 1511, 1512, 1521, and 1522. FIG. Between the upper burner 21 installed on the first side wall 110A and the corner (continuous point) C1 where the first side wall 110A and the third side wall 110C are continuous, the water stream ash removing device 1511, the upper burner 21, and the third side wall 110C. A water flow ash removing device 1512 is installed between the corner C4 where the first side wall 110A and the fourth side wall 110D are continuous. Similarly, between the upper burner 21 installed on the second side wall 110B and the corner C2 where the second side wall 110B and the third side wall 110C are continuous, the water flow ash removing device 1521, the upper burner 21, and the second side wall 110C A water flow ash removing device 1522 is installed between the corner C3 where the side wall 110B and the fourth side wall 110D are continuous. Since the water flow ash removing device is installed at the after-airport level from the burner, there are no particular restrictions on the horizontal installation locations of 110A and 110B, and 1511 may be installed at any position in the region X, for example. This is because the water flow ash removing device is arranged at a position higher than the burner in the vertical direction and not overlapping.

The water flow ash removal devices 1511 and 1521 inject water flow into the high potential area A3 on the third side wall 110C.

The water flow ash removal devices 1512, 1522 inject water flow into the high potential area A3 on the fourth side wall 110D.

6A, 6B, and 6C show another installation example of the water ash removing devices 151, 152, 153, and 154. FIG. The horizontal cross section of the combustion cylinder 11A in FIG. 6 is square.

The furnace 11 has a corner (continuous point) C1 where the first side wall 110A and the third side wall 110C are continuous, a corner C2 where the third side wall 110C and the second side wall 110B are continuous, and the second side wall 110B and the fourth side wall 110D. A burner 21 is provided at each of the continuous corner C3 and the continuous corner C4 between the fourth side wall 110D and the first side wall 110A. Since each burner 21 injects pulverized coal and primary air counterclockwise (counterclockwise) in FIGS. 6A, 6B, and 6C, a counterclockwise flame zone is generated in the center of the combustion tube 11A.

In FIG. 6A, water flow ash removing devices 153, 154, 151, and 152 are installed at the center in the width direction or depth direction of the first side wall 110A, the second side wall 110B, the third side wall 110C, and the fourth side wall 110D.

The water stream ash removing device 153 installed on the first side wall 110A is installed between the burners 21 installed at the center of the width direction of the first side wall 110A, that is, at the corners C1 and C4, and the high potential area A3 on the third side wall 110C. spray a stream of water on

The water stream ash removing device 151 installed on the third side wall 110C is installed in the center of the depth direction of the third side wall 110C, that is, between the burners 21 installed at the corners C1 and C2, and is located in the high potential area A3 on the second side wall 110B. spray a stream of water on

The water flow ash removing device 154 installed on the second side wall 110B is installed between the burners 21 installed at the center of the width direction of the second side wall 110B, that is, at the corners C2 and C3. spray a stream of water on

The water stream ash removing device 152 installed on the fourth side wall 110D is installed between the burners 21 installed at the center of the fourth side wall 110D in the depth direction, that is, at the corners C3 and C4. spray a stream of water on Accordingly, each of the water flow ash removing devices 151, 152, 153, 154 can avoid flames and spray water flow onto adjacent sidewalls.

The above is an example in which the flowing ash removing devices 151, 152, 153, and 154 are installed on each side wall, but depending on the size of the furnace, for example, as shown in FIG. can also be set to In this case, avoid the front flame zone and spray the water flow only in the direction of the side wall. For example, the water stream from the water stream ash remover 153 is jetted in the directions of the third side wall 110C and the fourth side wall 110D. The direction of the fourth side wall 110D, which is counter to the direction of swivel of the band, is difficult to reach. On the other hand, based on the same principle, the water flow from the water flow ash removal device 154 installed facing each other easily reaches the fourth side wall 110D, and if it does not easily reach the third side wall 110C, the water flow ash removal device 153 and the water flow ash removal device 154 are effective. It is complemented, and there is no problem as a removal range.

Further, in the above description, the water ash removal devices 153 and 154 are provided on each of the facing surfaces of the furnace, but as shown in FIG. It can also be installed on the surface only. For example, the water stream from the water stream ash remover 153 is jetted toward the third side wall 110C and the fourth side wall 110D. On the other hand, the water stream from the water stream ash remover 151 reaches the second side wall 110B and the first side wall 110A. This allows the water flow to reach any of the four sidewalls and remove the ash. In particular, in FIGS. 6B and 6C, there is an effect that the number of installed water ash removing devices can be reduced compared to the installation example of FIG. 6A.

According to the present embodiment, ash removal in the high potential region A3 where sulfidation corrosion and ash adhesion are severe is performed by a water stream ash removal device or the like, and ash removal downstream of the high potential region A3 is performed by a wall blower. This makes it possible to effectively remove ash from the high potential region A3 and prevent erosion and accompanying compound thinning.

This makes it possible to burn coal that suffers severe sulfidation corrosion and ash adhesion, expands the operating range, and reduces fuel costs.

In addition, the number of wall blowers to be installed can be reduced, and the initial cost and operating cost due to steam loss can be reduced as compared with the case where the ash is removed only by the wall blower.

In addition, overlaying and thermal spraying in the high potential area A3 are not required, and the initial cost can be reduced.

In addition, it becomes easier to control the exhaust gas temperature, the steam temperature, etc., and the operability is improved.

In addition, damage to the hopper 62 due to falling ash and tube leaks due to steam temperature fluctuations can be prevented, reducing maintenance costs and shortening the regular inspection schedule.

The above embodiments do not limit the present invention, and modifications within the scope of the present invention are included in the present invention.

For example, the shape of the combustion tube 11A of the furnace 11 is not limited to a square tube shape, and may be a cylindrical shape.

In addition, the purpose of the present invention is to remove ash in the high potential region A3 with a water flow ash removal device, and to remove ash in a downstream region of the combustion gas with a wall blower. If the ash removal area is the high potential area A3, the installation position of the water flow ash removal device is outside the high potential area A3, for example, above the upper burner, and the nozzle injection angle is adjusted so that the high potential area A3 is ash. You may adjust so that it may become a removal area|region.

Moreover, although the example in which the burners 21 are installed at the four corners of the furnace 11 has been described above, the installation positions of the burners 21 are not limited to the four corners. For example, as shown in FIG. 10(a), two burners 21 are installed on each of a pair of opposing side wall surfaces, the third side wall 110C and the fourth side wall 110D, by adjusting the injection angle in a direction in which swirl combustion can be performed. may In FIG. 10(a), swirling combustion is performed counterclockwise to form a flame zone.

Also, a plurality of flame zones may be formed within the furnace 11 . For example, as shown in FIG. 10(b), a total of eight burners 21 are installed, two at each of the four corners, two side walls, the third side wall 110C and the fourth side wall 110D. Four burners 21 installed behind the center in the depth direction of the furnace 11 (upper side in FIG. 10) form one flame zone, and in front of the center along the depth direction of the furnace 11 (lower side in FIG. 10). ) may form another flame zone with four burners 21 installed in the . In this case also, the high potential area is removed by the water flow ash removal device, and the wall blower is used to remove the ash above the after-air port, thereby obtaining the same effect as the above embodiment.

10, 700, 900: Boilers 11, 711, 911: Furnace 11A: Combustion tube 12: Combustion device 13: Flue ducts 21, 22, 23, 721, 921: Burners 26, 27, 28: Pulverized coal supply pipes 31, 32 , 33: Crusher 36: Wind boxes 37a, 37b: Air duct 38: Blowers 39, 739, 939: After airport 48: Exhaust gas passage 49: Air heater 50: Denitration device 51: Dust treatment device 52: Induced draft fan 53: Chimney 62 : Hopper 70 : Furnace bottom evaporator 110A : First side wall 110B : Second side wall 110C : Third side wall 110D : Fourth side wall 151, 152, 1511, 1512, 1521, 1522, 153, 154: Water flow ash removal device 171, 172, 173, 174: wall blower

Claims (4)

A furnace for two-stage combustion of fuel by supplying air,
a bottom;
a cylindrical combustion cylinder installed along the vertical direction on the bottom;
a burner that is provided on the side wall of the combustion cylinder and burns fuel with an air amount less than the theoretical air amount;
an after air port installed vertically above the installation position of the burner on the side wall of the combustion cylinder and supplying secondary air for two-stage combustion into the combustion cylinder;
A stream of water is injected into a first height region from the upper side of the burner installation position to the lower side of the after-airport installation position on the side wall of the combustion cylinder to remove ash adhering to the first height region. a water flow ash removal device,
a wall blower that injects steam or air into a second height region above the installation position of the after air port on the side wall of the combustion cylinder to remove ash adhering to the second height region;
with
The combustion cylinder is formed in a hollow shape with a square horizontal cross section,
a first sidewall;
a second sidewall facing the first sidewall in a first direction in a horizontal plane;
a third sidewall that connects each of the first sidewall and the second sidewall along the first direction;
A fourth side wall that connects the first side wall and the second side wall along the first direction, and faces the third side wall in a second direction perpendicular to the first direction in the horizontal plane. a fourth sidewall to
including
At least two or more of the burners are provided in the furnace, and at least one or more of the plurality of burners are installed on each of the first side wall and the second side wall,
At least two or more of the water ash removal devices are provided in the furnace, and at least one or more of each of the plurality of water ash removal devices is installed on each of the third side wall and the fourth side wall,
a water stream ash removing device installed on the third side wall injects a water stream into the first height region of the fourth side wall;
The furnace according to claim 1, wherein the water flow ash removing device installed on the fourth side wall injects water flow into the first height region of the third side wall. A furnace for two-stage combustion of fuel by supplying air,
a bottom;
a cylindrical combustion cylinder installed along the vertical direction on the bottom;
a burner that is provided on the side wall of the combustion cylinder and burns fuel with an air amount less than the theoretical air amount;
an after air port installed vertically above the installation position of the burner on the side wall of the combustion cylinder and supplying secondary air for two-stage combustion into the combustion cylinder;
A stream of water is injected into a first height region from the upper side of the burner installation position to the lower side of the after-airport installation position on the side wall of the combustion cylinder to remove ash adhering to the first height region. a water stream ash removal device that
a wall blower that injects steam or air into a second height region above the installation position of the after air port on the side wall of the combustion cylinder to remove ash adhering to the second height region;
with
The combustion cylinder is formed in a hollow shape with a square horizontal cross section,
a first sidewall;
a second sidewall facing the first sidewall in a first direction in a horizontal plane;
a third sidewall that connects each of the first sidewall and the second sidewall along the first direction;
A fourth side wall that connects the first side wall and the second side wall along the first direction, and faces the third side wall in a second direction perpendicular to the first direction in the horizontal plane. a fourth sidewall to
including
At least two or more of the burners are provided in the furnace, and at least one or more of the plurality of burners are installed on each of the first side wall and the second side wall,
At least four or more of the water flow ash removal devices are provided in the furnace,
The first stream ash removing device installed on the first side wall is installed between the burner installed on the first side wall and a connecting point of the first side wall and the third side wall, and jetting a water stream to the first height region;
A second stream ash removing device installed on the first side wall is installed between the burner installed on the first side wall and a connecting point of the first side wall and the fourth side wall, and the Injecting a water flow into the first height region,
A third stream ash removing device installed on the second side wall is installed between the burner installed on the second side wall and a connecting point of the second side wall and the third side wall, and the Injecting a water flow into the first height region,
A fourth stream ash removing device installed on the second side wall is installed between the burner installed on the second side wall and a connecting point of the second side wall and the fourth side wall, and the A furnace characterized by injecting a stream of water into the first height region. A furnace for two-stage combustion of fuel by supplying air,
a bottom;
a cylindrical combustion cylinder installed along the vertical direction on the bottom;
a burner that is provided on the side wall of the combustion cylinder and burns fuel with an air amount less than the theoretical air amount;
an after air port installed vertically above the installation position of the burner on the side wall of the combustion cylinder and supplying secondary air for two-stage combustion into the combustion cylinder;
A stream of water is injected into a first height region from the upper side of the burner installation position to the lower side of the after-airport installation position on the side wall of the combustion cylinder to remove ash adhering to the first height region. a water flow ash removal device,
a wall blower that injects steam or air into a second height region above the installation position of the after air port on the side wall of the combustion cylinder to remove ash adhering to the second height region;
with
The combustion cylinder has a hollow rectangular horizontal cross section,
a first sidewall;
a second sidewall facing the first sidewall in a first direction in a horizontal plane;
a third sidewall that connects each of the first sidewall and the second sidewall along the first direction;
A fourth side wall that connects the first side wall and the second side wall along the first direction, and faces the third side wall in a second direction perpendicular to the first direction in the horizontal plane. a fourth sidewall to
including
At least four burners are provided in the furnace,
A first burner is installed at a continuation point of the first side wall and the third side wall,
A second burner is installed at a continuation point of the third side wall and the second side wall,
A third burner is installed at a continuation point of the second side wall and the fourth side wall,
A fourth burner is installed at a continuation point of the fourth side wall and the first side wall,
At least four of the water flow ash removal devices are provided in the furnace,
a first water stream ash removing device installed on the first side wall, installed between the first burner and the fourth burner, and injecting water stream into the first height region on the third side wall;
a second water stream ash removing device installed on the third side wall, installed between the first burner and the second burner, and injecting a water stream into the first height region of the second side wall;
a third water stream ash removal device installed on the second side wall, installed between the second burner and the third burner, and injecting a water stream into the first height region on the fourth side wall;
A fourth water stream ash removing device installed on the fourth side wall is installed between the third burner and the fourth burner, and jets a stream of water to the first height region on the first side wall. A furnace characterized by A boiler comprising the furnace according to any one of claims 1 to 3 .

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