JP6866172B2 - Swirling combustion boiler - Google Patents

Description

The present invention relates to a swirl combustion boiler.

A swirl combustion boiler that burns pulverized fuel such as coal, biomass, and carbide by a swirl combustion method is known.

As disclosed in Patent Document 1, the swirl combustion boiler includes a burner portion provided with a burner for burning the pulverized fuel put into the furnace. A plurality of burners are provided at each corner of the furnace at intervals in the circumferential direction. Each burner burns a mixture of pulverized fuel and primary air to produce a flame. The flames ejected from these multiple burners form a swirling flow in the furnace. Here, each of the plurality of burners is provided so as to eject a flame in a direction inclined in the horizontal plane with respect to the center of the furnace so that the swirling flow swirls in the furnace. The swirling flow generated by the flames ejected from multiple burners spirally rises while swirling in the furnace.

Japanese Patent No. 52716660

By the way, slag generated by combustion of pulverized fuel may be deposited on a burner protruding into the furnace from a swirling flow that spirally rises while swirling in the furnace to form a clinker.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a swirl combustion boiler capable of suppressing the accumulation of clinker in a furnace.

In order to solve the above problems, the swirl combustion boiler of the present invention employs the following means.
The swirling combustion boiler according to the first aspect of the present invention includes a tubular fireplace having a rectangular shape in a plan view and extending in the vertical direction, and a plurality of burners provided in the fireplace at intervals in the circumferential direction. and a burner unit for forming the circumferential direction of the swirl flow by burning a pulverized fuel in said furnace by said burner, a plurality of said burners, each said burner height position of the vertical direction It is characterized in that it is provided so as to be gradually lowered from the upstream side to the downstream side in the swirling direction of the swirling flow so that there is only one.

According to this configuration, the swirling flow generated by a plurality of burners provided at intervals in the circumferential direction in the furnace spirally rises while swirling in the circumferential direction in the furnace. Therefore, the flame ejected from each burner swirls in the swirling direction of the swirling flow and heads upward. Therefore, the burner provided at a position lower than the other burners on the upstream side is not exposed to the upward flame while spouting from the other burners on the upstream side and swirling, and has a large vertical interval. It will be separated. Therefore, it becomes difficult for clinker to accumulate on the burner provided at a low position.
Further, according to this configuration, clinker is less likely to be deposited on all the burners provided on the downstream side in the swirling direction of the swirling flow with respect to the burner provided at the highest position.

In the first aspect, wherein the burner unit includes a plurality of said burners, comprising a plurality of stages with an interval in the vertical direction in the furnace, in each stage, a plurality of said burners, each of said vertical It is more preferable that the burner is provided so as to be gradually lowered from the upstream side to the downstream side in the swirling direction of the swirling flow so that there is only one burner at the height position.

According to this configuration, even when a plurality of burners are provided in a plurality of stages in the vertical direction, clinker is less likely to be deposited in the burners provided in each stage at a position lower than the other burners on the upstream side.

In the first aspect, it is more preferable that the burner provided on the downstream side of the swirling flow in the swirling direction with respect to the corner portion of the furnace is provided at the lowest position among the plurality of the burners. is there.

When the burner is provided on the downstream side in the swirling direction with respect to the corner of the furnace, the swirling flow changes its direction at the corner of the furnace and then collides with the burner provided on the downstream side of the burner. For this reason, stagnation is likely to occur in the swirling flow between the corner of the furnace and the burner provided on the downstream side thereof. By providing the burner at a position lower than other burners on the upstream side in such a portion where stagnation is likely to occur, it is possible to suppress the accumulation of clinker on the burner.

In the first aspect, it is more preferable that at least one of the plurality of burners is provided on the upstream side of the swirling flow in the swirling direction with respect to the corner portion of the furnace.

According to this configuration, by providing the burner on the upstream side of the swirling flow in the swirling direction with respect to the corner of the furnace, stagnation occurs in the swirling flow as in the case where the burner is provided on the downstream side of the corner of the furnace. Can be suppressed. This makes it possible to prevent clinker from accumulating at the corners of the furnace.

In the first aspect, an air supply unit for supplying air into the furnace is provided above the burner unit, and the air supply units are provided at a plurality of intervals in the circumferential direction in the furnace. It is more preferable that the air ejection nozzles are provided, and the plurality of the air ejection nozzles are provided vertically above each of the plurality of burners at a predetermined distance.

According to this configuration, when the air supply unit is provided above the burner unit, a plurality of air ejection nozzles provided above the burner unit are vertically separated from each other by a predetermined distance. As a result, it is possible to secure the residence time of the swirling flow that rises while swirling in the circumferential direction from the burner portion.

According to the present invention, it is possible to suppress the accumulation of clinker in the furnace.

It is a vertical cross-sectional view which shows the whole schematic structure of the swirl combustion boiler which concerns on 1st Embodiment of this invention, and is the I-I arrow cross-sectional view of FIG. It is a plan sectional view of the swirl combustion boiler which concerns on 1st Embodiment of this invention. It is a vertical cross-sectional view which shows the whole schematic structure of the swirl combustion boiler which concerns on 2nd Embodiment of this invention, and is the cross-sectional view | FIG. It is a plan sectional view of the swirl combustion boiler which concerns on 2nd Embodiment of this invention.

Hereinafter, embodiments of the swirl combustion boiler according to the present invention will be described with reference to the drawings.
[First Embodiment]
Hereinafter, the first embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 1, the swirl combustion boiler 20A includes a furnace 21, a burner section 30A, an additional air input section (air supply section) 40, a superheater 22, a reheater 23, and an economizer 24. , Is equipped.

The furnace 21 has a rectangular shape in a rectangular cross-sectional view and has a tubular shape extending in the vertical direction. A plurality of heat transfer tubes (not shown) are provided on the furnace wall 21w forming the inner surface of the furnace 21. Each of these plurality of heat transfer tubes (not shown) extends in the vertical direction, and water is supplied from the outside.

The superheater 22 is provided above the furnace 21.
The reheater 23 and the economizer 24 are provided in the flue 25A connected to the upper outlet of the furnace 21.

The burner portion 30A is provided in the lower part of the furnace 21. As shown in FIG. 2, the burner portion 30A includes a plurality of burners 31A, 31B, 31C, and 31D provided at intervals in the circumferential direction in the furnace 21.
In this embodiment, in the burner section 30A, a plurality of burners 31A, 31B, 31C, and 31D are provided in two stages (plurality of stages) at intervals in the vertical direction in the furnace 21.

Each of the burners 31A, 31B, 31C, and 31D ejects a mixture of primary air and pulverized fuel into the furnace 21, burns the pulverized fuel, and generates a flame in the furnace 21. The flames generated by each of the plurality of burners 31A, 31B, 31C, and 31D in the circumferential direction form a swirling flow F. The swirling flow F spirally rises in the furnace 21 while swirling in the circumferential direction.
The burners 31A, 31B, 31C, and 31D are provided on each of the four side surfaces 21a, 21b, 21c, and 21d of the furnace 21 so as to penetrate from the outside to the inside of the furnace 21. The base end 31b of the burners 31A, 31B, 31C, and 31D is fixed to the furnace wall 21w on the upstream side of the swirling flow F in the swirling direction Sw with respect to the corner portion 21k of the furnace 21. The tip 31a of the burners 31A, 31B, 31C, 31D is provided so as to project inward of the furnace wall 21w and be inclined in the horizontal plane so as to inject a flame toward the downstream side of the swirling direction Sw of the swirling flow F. ing.

The plurality of burners 31A, 31B, 31C, 31D of each stage are provided so as to be gradually lowered from the burner 31A on the upstream side of the swirling direction Sw of the swirling flow F toward the burners 31B, 31C, 31D on the downstream side. There is.

As shown in FIG. 1, the additional air injection section 40 is provided above the burner section 30A in the furnace 21. The additional air injection unit 40 includes a plurality of air ejection nozzles 41 provided at intervals in the circumferential direction in the furnace 21. Each air ejection nozzle 41 sends secondary air into the furnace 21 from the outside of the furnace 21. Each air ejection nozzle 41 penetrates from the outside to the inside of the furnace 21 and projects inward of the furnace wall 21w.
A plurality of air ejection nozzles 41 provided at intervals in the circumferential direction are provided vertically above each of the burners 31A, 31B, 31C, and 31D provided in the circumferential direction. Each air ejection nozzle 41 is provided vertically above the burners 31A, 31B, 31C, and 31D at a predetermined distance.
By injecting combustion air from the additional air input unit 40, the region from the burner unit 30A to the additional air input unit 40 is made into a reducing atmosphere.

According to the configuration as described above, in the burner portion 30A, a plurality of burners 31A, 31B, 31C, 31D provided at intervals in the circumferential direction are moved from the upstream side to the downstream side of the swirling direction Sw of the swirling flow F. It is provided so that it gradually decreases toward the bottom.
According to such a swirl combustion boiler 20A, the burners 31B, 31C, and 31D provided at a position lower than the burner 31A on the upstream side ejects from the burner 31A on the upstream side and turns upward with a flame (swirl). With respect to the flow F), a large interval is provided in the vertical direction. Therefore, it becomes difficult for clinker to accumulate on the burners 31B, 31C, and 31D provided at low positions. That is, clinker is less likely to be deposited on all the burners 31B, 31C, and 31D provided on the downstream side of the swirling direction Sw of the swirling flow F with respect to the burner 31A provided at the highest position.

Further, the plurality of burners 31A, 31B, 31C, and 31D are provided on the upstream side of the swirling direction Sw of the swirling flow F with respect to the corner portion 21k of the furnace 21.
As a result, when the burners 31A, 31B, 31C, and 31D are provided on the downstream side of the corner portion 21k of the furnace 21, the swirling flow F becomes stagnation, but on the upstream side of the corner portion 21k in the swirling direction Sw. By providing the burners 31A, 31B, 31C, and 31D, the occurrence of stagnation can be suppressed. As a result, it is possible to prevent the clinker from accumulating on the corner portion 21k of the furnace 21. The corner portion 21k is not only the portion of the furnace 21 where the furnace walls and the furnace walls are adjacent to each other in the circumferential direction, but also the portion where the furnace wall and the furnace wall intersect in the circumferential direction of the furnace 21. Includes the vicinity of the circumferential end of the expanding furnace wall.

Further, an additional air input unit 40 for supplying air into the furnace 21 is provided above the burner unit 30A, and the additional air input unit 40 is above the burners 31A, 31B, 31C, and 31D with respect to each of the plurality of burners 31A, 31B, 31C, and 31D. A plurality of air ejection nozzles 41 provided in the above are vertically separated by a predetermined distance. As a result, it is possible to secure a residence time of the swirling flow F rising from the burner portion 30A while swirling in the circumferential direction. Therefore, NOx can be reliably reduced.

In the first embodiment, the plurality of burners 31A, 31B, 31C, and 31D provided in the circumferential direction are provided so as to be gradually lowered from the upstream side to the downstream side of the swirling direction Sw of the swirling flow F. Not limited to.
For example, at least one of the plurality of burners 31A, 31B, 31C, 31D may be provided at a position lower than the other burners 31A, 31B, 31C, 31D located on the upstream side of the swirling flow F in the swirling direction Sw. Just do it.
According to such a configuration, in the burners 31A, 31B, 31C, 31D provided at a position lower than the other burners 31A, 31B, 31C, 31D on the upstream side, the other burners 31A, 31B, 31B on the upstream side, It is not exposed to the flame (swirl flow F) that erupts from 31C and 31D and swirls upward, and is separated by a large distance in the vertical direction. Therefore, clinker is less likely to be deposited on the burners 31A, 31B, 31C, and 31D provided at the lower position of the furnace 21.

[Second Embodiment]
Next, a second embodiment of the swirl combustion boiler according to the present invention will be described. In the following description, the same reference numerals will be given to the configurations common to the first embodiment, and the description thereof will be omitted.

As shown in FIG. 3, the swirl combustion boiler 20B includes a furnace 21, a burner section 30B, an additional air input section 40, a superheater 22, a reheater 23, and an economizer 24. ..
In this embodiment, in the swirl combustion boiler 20B, the side surface 21d on the wake side of the furnace 21 is arranged adjacent to the flue 25B on the wake side.

The burner portion 30B is provided at the lower part in the furnace 21. As shown in FIG. 4, the burner portion 30B includes a plurality of burners 31A, 31B, 31C, and 31D provided at intervals in the circumferential direction in the furnace 21.
The burners 31A, 31B, 31C, and 31D are provided on each of the four side surfaces 21a, 21b, 21c, and 21d of the furnace 21 so as to penetrate from the outside to the inside of the furnace 21. Of the plurality of burners 31A, 31B, 31C, 31D, the three burners 31A, 31B, 31C have their base end 31b on the upstream side of the swirling direction Sw of the swirling flow F with respect to the corner portion 21k of the furnace 21. It is fixed to the side surfaces 21a, 21b, 21c. Further, the base end portion 31b of the remaining burner 31D is fixed to the corner portion 21k of the furnace 21 on the side surface 21b which is downstream of the swirling direction Sw of the swirling flow F. This is because the flue 25B is provided adjacent to the side surface 21b, so that the base end portion 31b of the burner 31D is placed on the side surface 21d on the upstream side of the swirling direction Sw of the swirling flow F with respect to the corner portion 21k of the furnace 21. This is because it cannot be fixed to.

Here, the burner 31D provided on the downstream side of the swirling direction Sw of the swirling flow F with respect to the corner portion 21k of the furnace 21 is provided at the lowest position among the plurality of burners 31A, 31B, 31C, 31D. ing. Further, when a plurality of burners 31A, 31B, 31C, 31D are provided so as to be gradually lowered from the upstream side to the downstream side of the swirling flow F in the swirling direction Sw, the burner 31D is at the lowest position. To do so.

According to the configuration as described above, in the burner portion 30B, the burner 31D provided on the downstream side of the swirling direction Sw of the swirling flow F with respect to the corner portion 21k of the furnace 21 includes a plurality of burners 31A, 31B, 31C. , 31D, which is provided at the lowest position.
Here, since the burner 31D is provided on the downstream side of the turning direction Sw with respect to the corner portion 21k of the furnace 21, the swirling flow F changes its direction at the corner portion 21k of the furnace 21 and then is on the downstream side thereof. When it collides with the burner 31D provided in the above, stagnation is likely to occur at the portion P between the corner portion 21k and the burner 31D. However, by providing the burner 31D at a position lower than the other burners 31A, 31B, 31C on the upstream side in the portion P where stagnation is likely to occur, it is possible to suppress the accumulation of clinker on the burner 31D. ..

Further, the plurality of burners 31A, 31B, 31C are provided on the upstream side of the swirling direction Sw of the swirling flow F with respect to the corner portion 21k of the furnace 21.
According to such a swirling combustion boiler 20B, by providing the burners 31A, 31B, and 31C on the upstream side of the swirling flow F in the swirling direction Sw with respect to the corner portion 21k of the furnace 21, the swirling flow F becomes stagnation. Can be suppressed. As a result, it is possible to prevent clinker from accumulating on the corner portion 21k of the furnace 21.

The present invention is not limited to the above-described embodiment, and can be appropriately changed within a range that does not deviate from the gist, such as the number of burner stages and the number of swirling flows formed for each stage.

20A, 20B Swirling combustion boiler 21 Fire furnace 21a, 21b, 21c, 21d Side surface 21k Corner 21w Furnace wall 22 Superheater 23 Reheater 24 Economizer 25A, 25B Flue 30A, 30B Burner 31A-31D Burner 31a Tip 31b Base end 40 Additional air inlet (air supply)
41 Air ejection nozzle F Swirling flow Sw Swirling direction

Claims (5)

A rectangular furnace with a rectangular cross-section and extending in the vertical direction,
A plurality of burners provided at intervals in the circumferential direction in the furnace are provided, and a burner portion for burning fine fuel in the furnace by the plurality of burners to form a swirling flow in the circumferential direction is provided. ,
A plurality of said burners are each the so the burner in the vertical direction of the height is only one, is provided so as to be stepwise lower toward the downstream side from the turning direction upstream side of the swirling flow A swirling combustion boiler characterized by being The burner unit is provided with a plurality of the burners in a plurality of stages at intervals in the vertical direction in the furnace.
In each stage, a plurality of said burners, each of the as the burner in the vertical height position is only one, stepwise lowered from the turning direction upstream side of the swirling flow toward the downstream side pivoting the combustion boiler according to claim 1, characterized in that as provided comprising. The swirl combustion boiler according to claim 1 or 2 , wherein at least one of the plurality of burners is provided on the upstream side of the swirl flow in the swirl direction with respect to a corner portion of the furnace. Claims 1 to 3 are characterized in that the burner provided on the downstream side of the swirling flow in the swirling direction with respect to the corner portion of the furnace is provided at the lowest position among the plurality of the burners. The swirling combustion boiler according to any one of the above. An air supply unit for supplying air into the furnace is provided above the burner unit.
The air supply unit includes a plurality of air ejection nozzles provided at intervals in the circumferential direction in the furnace.
The swivel according to any one of claims 1 to 4 , wherein the plurality of air ejection nozzles are provided vertically above each of the plurality of burners at a predetermined distance. Burning boiler.

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