JP3891958B2 - Combustion apparatus and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a combustion apparatus and method that can efficiently burn biomass, which is a low-priced coal alternative fuel, in an industrial boiler or the like.
[0002]
[Prior art]
Co-firing of coal and biomass, industrial boilers, in utility boiler further various turbine, fuel cost reduction by inexpensive fuel used, more can be utilized in the amount of CO ₂ produced inhibition, thus CO ₂ emissions trading fossil fuel Therefore, in recent years, the promotion of its use has been screamed, and in the US, deregulation is being implemented in addition to the renewable use policy.
[0003]
FIG. 7 shows an example of coal combustion equipment for burning coal into fine powder.
As shown in FIG. 7, a burner 202 that cooperates with a pulverized coal nozzle and an air nozzle is disposed in a furnace main body 201 of a boiler, and in the furnace 203, transmission corresponding to a heater, an evaporator, a economizer, and the like. A heat tube group 204 is installed. The combustion exhaust gas 205 generated by the combustion of pulverized coal in the furnace 203 heats the heat transfer tube group 204 and is sent to the flue 206. An air heater (AH) 207 is disposed in the middle of the flue 206, and the combustion exhaust gas 205 in the flue 206 is drawn by an induction fan (IDF) 208 to collect the air heater (AH) 207 and ash collection. It is emitted from the chimney 210 to the atmosphere via the device 209.
[0004]
In order to burn the coal, coal 212 supplied from an external facility (not shown) is supplied from the coal bunker 213 to the coal pulverizer 214, and the coal pulverizer 214 converts the coal into pulverized coal. It is pulverized and dried by hot air 215 heated by an air heater 207. Thereafter, the pulverized coal is conveyed from the coal pulverizer 214 by the hot air 215 and supplied to the pulverized coal nozzle in the burner 202 from the pulverized coal supply line 217 as the pulverized coal mixture 216. Burned (Patent Document 1).
[0005]
A recirculation gas line 218 for the bottom of the furnace branches off from the flue 206, and a part of the combustion exhaust gas 205 is used as a recirculation gas for the bottom of the furnace (GR) 219. Is fed to the bottom of the boiler body 201.
[0006]
Reference numeral 221 denotes combustion air, which is drawn by a forced air blower (FDF) 222 and is heated from the combustion air line 223 via the main burner air line 224 by the air heater (AH) 207 to be heated by the main burner. The combustion air is supplied from the air nozzle in the burner 202 into the furnace 203.
Moreover, it branches from the combustion air line 223, is sent to the hot air line 226 for coal pulverization by the blower 225, is heated by the air heater (AH) 207 on the way, and is used as the hot air 215 for coal pulverization. And supplied to the coal pulverizer 214.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-28129
[Problems to be solved by the invention]
However, using the above-described coal fuel facility, when biomass is simply supplied instead of coal and burned in the furnace 203, the particle size of the biomass is as large as several millimeters, and conventional coal is pulverized by a pulverization mill. Since it is not as fine as 10 μm like pulverized coal, there is a problem of poor ignitability.
As a result, there are problems that the amount of unburned fuel increases and the generation of CO and NOx increases due to incomplete combustion.
[0009]
The reason why the particle size of the biomass cannot be made fine is that because the biomass is not a brittle material like coal, even if it is pulverized by a pulverizing means, it cannot be pulverized efficiently.
For this reason, there exists a problem that the biomass of the large particle size which cannot float in a furnace bottom part falls, and causes slag.
For this reason, the advent of technology that improves the ignitability of biomass in a furnace is eagerly desired.
[0010]
This is also an important issue in a coal / biomass co-fired furnace because there is also a problem when coal and biomass are used in combination and burned in the furnace.
[0011]
This invention makes it a subject to provide the combustion apparatus and method which can burn biomass efficiently with a combustion installation in view of the said problem.
[0012]
[Means for Solving the Problems]
1st invention which solves the subject mentioned above is a combustion apparatus which supplies biomass in a furnace body, and burns, Comprising: Biomass with a small particle size is put in the furnace centering on biomass with a large particle size around it A combustion apparatus comprising a supply burner.
[0013]
2nd invention is a combustion apparatus which supplies biomass in a furnace main body and burns, Comprising: The 1st burner which supplies biomass with a large particle size into a furnace, and supplies biomass with a small particle size into a furnace A combustion apparatus comprising a second burner.
[0014]
According to a third invention, in the second invention, the first burner is provided at a combustion gas upstream position of the furnace body, and the second burner is provided at a combustion gas downstream position of the furnace body. In the device.
[0015]
According to a fourth invention, in the second invention, the first burner is provided at a combustion gas downstream position of the furnace body, and the second burner is provided at a combustion gas upstream position of the furnace body. In the device.
[0016]
A fifth invention is the combustion apparatus according to any one of the second to fourth inventions, further comprising classifying means for classifying the biomass supplied to the first burner and the second burner.
[0017]
A sixth invention provides the first burner and the second burner according to any one of the second to fifth inventions, and sets the injection angle so that the first and second burners are inclined with respect to the horizontal direction. The combustion apparatus is characterized by being provided with. Each of the first and second burners can be provided in a plurality of stages. Further, it is possible to provide an adjusting means for changing the burner injection angle so that the burner injection angle can be appropriately adjusted.
[0018]
A seventh invention is the invention according to any one of the second to sixth inventions, wherein the blow of the first burner and the second burner is swirled, and the virtual circle diameter ratio of the first burner is the virtual circle of the second burner. The combustion apparatus is characterized by being smaller than the diameter ratio.
[0019]
An eighth invention is the combustion apparatus according to any one of the second to seventh inventions, wherein a grate is provided at the furnace bottom.
[0020]
A ninth aspect of the invention is the combustion apparatus according to the eighth aspect, wherein a hot air supply port for supplying hot air into the furnace is provided between the grate and the lowermost burner at the bottom of the furnace. In the device.
[0021]
A tenth aspect of the invention is a combustion method in which biomass is supplied into the furnace body and burned, the biomass having a large particle size as a center, and a biomass having a small particle size being supplied into the furnace around the biomass. It is in the combustion method characterized by these.
[0022]
An eleventh aspect of the invention is the tenth aspect of the invention, in which the biomass injection is performed while swirling, and the virtual circle diameter ratio by the injection of biomass with a large particle size is greater than the virtual circle diameter ratio by the injection of biomass with a small particle size The combustion method is characterized by being small.
[0023]
A twelfth aspect of the invention is a combustion method for supplying biomass into the furnace body and burning it, supplying biomass having a large particle size from the first burner into the furnace, and biomass having a small particle size from the second burner. It is in the combustion method to be fed inside.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Although the form of this invention is demonstrated below, this invention is not limited to these embodiment.
[0025]
[First Embodiment]
A combustion apparatus according to the present embodiment will be described with reference to FIG.
As shown in FIG. 1, the combustion apparatus according to the present embodiment is a combustion apparatus that supplies and burns biomass 11 into a furnace body 12, and mainly focuses on biomass (large-diameter biomass) 11 </ b> A having a large particle size. In addition, a burner 13 for supplying biomass (small-diameter biomass) 11B having a small particle diameter into the furnace is provided around it.
[0026]
The burner 13 has a large-diameter biomass ejection portion 13a that ejects biomass 11 into the furnace at the center thereof, a small-diameter biomass ejection portion 13b that is provided outside the small-diameter biomass 11B and is disposed on the outermost periphery. And it is comprised from the hot air ejection part 41c which supplies the hot air 35 in a furnace.
[0027]
Biomass is pulverized to a few millimeters by pulverizing means, and fine particles of 1 mm or less are present therein. By classifying the fine particles by classification means, biomass 11A having a large particle diameter of 1 mm or more and biomass 11B having a small particle diameter of less than 1 mm are obtained.
[0028]
The average particle diameter of the biomass 11A having a large particle diameter of 1 mm or more is about several millimeters, preferably 2 to 3 mm. The average particle size of biomass 11B having a small particle size of less than 1 mm is preferably about 0.5 mm.
[0029]
In the present invention, biomass refers to biological resources. Examples of biomass include agricultural products or by-products, wood, plants, and the like. Depending on the purpose of biomass conversion, from the viewpoint of fuel and raw material supply, those that are easily available in large quantities and those that have a stable supply as fuel and raw materials, such as those with fast growth and growth rates, are available. preferable. Examples of herbaceous / woody plant biomass include corn, rice, sugarcane such as sweet sorghum, pastures such as napiergrass, and wood. Moreover, in this invention, you may use the organic waste which can be used as an alternative raw material of biomass.
[0030]
As this classifying means, a known classifying means is used. For example, in the case shown in FIG. 1, a vibrating sieve 21 inclined obliquely is used.
[0031]
By setting it as the burner 13 of the said structure, the biomass 11B with a small particle diameter with good ignitability first ignites, and the stable flame 14 is formed. Then, by the radiant heat of the flame 14. Since the biomass 11A having a large particle size inferior in ignitability can be stably ignited, the biomass 11A having a large particle size can also be surely burnt completely.
[0032]
[Second Embodiment]
A combustion apparatus according to the present embodiment will be described with reference to FIG.
As shown in FIG. 2, the combustion apparatus according to the present embodiment is a combustion apparatus that supplies biomass 11 into the furnace body 12 and combusts it, and supplies the biomass 11A having a large particle size into the furnace. A burner 31 and a second burner 32 for supplying biomass 11B having a small particle size into the furnace are provided. Reference numeral 30 indicates combustion gas.
[0033]
In the present embodiment, the first and second burners 31 and 32 are of the two-stage type, but the present invention is not limited to this. Moreover, hot air (not shown) is introduced into the first and second burners 31 and 32 so that efficient combustion is performed.
[0034]
Moreover, in this Embodiment, while providing the 1st burner 31 which supplies the biomass 11A with the said large particle size in the downstream position (furnace low part side) of the combustion gas 30 of the furnace main body 12, the biomass 11B with the said small particle size is provided. Is provided downstream of the combustion gas 30 in the furnace body 12 (on the upper side of the furnace).
[0035]
Thereby, the biomass 11B with a small particle size can rise and burn in the furnace. Further, when the biomass 11A having a large particle size falls to the bottom of the furnace, the particle size becomes small due to the biomass combustion radiant heat, and a part of the biomass 11A burns. The dropped residue 34 is burned in the grate 36 by hot air 35 introduced separately.
[0036]
Further, a hot air supply port 37 for supplying hot air 35 to the furnace separately may be provided between the grate 36 and the first burner 31 to burn the biomass 11A having a large particle size during the settling. .
[0037]
[Third Embodiment]
The combustion apparatus according to the present embodiment will be described with reference to FIG.
As shown in FIG. 3, the combustion apparatus according to the present embodiment is a combustion apparatus that supplies and burns biomass 11 into the furnace body 12, and burns the biomass 11 </ b> A having a large particle size into the furnace. First burners 31-1 and 31-2 and a plurality of second burners 32-1 and 32-2 for supplying biomass 11B having a small particle size into the furnace, and the combustion gas downstream side (furnace The second burner 32-1 on the upper side is inclined downward, and the first burner 31-2 on the combustion gas upstream side (furnace lower side) is inclined upward. Injection angle of each burner is tilted, the second burner 32-1 is set to - [theta] ₁ with respect to the horizontal plane, the first burner 31-2 is set to + theta ₂ with respect to the horizontal plane.
[0038]
As a result, the second pass burner 32-1 on the upper stage side of the plurality of stages is inclined downward to prevent a short path of the biomass 11B having a small particle size.
Further, by tilting the first burner 31-2 on the lower stage side of the plurality of stages upward, the falling residence time of the biomass 11A having a large particle diameter is increased, and combustion of biomass having large particles is performed by combustion by radiant heat. Try to promote.
[0039]
[Fourth Embodiment]
A combustion apparatus according to the present embodiment will be described with reference to FIG.
As shown in FIG. 4, the combustion apparatus according to the present embodiment classifies the biomass that is supplied by the burner immediately before the burner.
A cyclone 41 for classifying the biomass 11A having a large particle size and the biomass 11B having a small particle size is provided in the vicinity of the furnace, and the cyclone 41 is used for classification. The biomass 11B having a small particle size is discharged from the inner cylinder 42 disposed in the cyclone, while the biomass 11A having a large particle size is discharged from the lower end of the cyclone. The supply pipe 43 provided in the lower part of the cyclone is provided with an air feeding / conveying means for supplying hot air 35 and the like.
[0040]
Note that this air transporting means may use hot air, water vapor, gas having a low oxygen concentration (exhaust gas from the combustion facility), or the like. Here, when hot air is used, biomass does not have a high ignition temperature like coal (ignition temperature is as low as 250 ° C.), so it may ignite, but the destination is a burner. There is no.
[0041]
[Fifth Embodiment]
A combustion apparatus according to the present embodiment will be described with reference to FIG.
As shown in FIGS. 5A to 5C, the first burner 31 and the second burner 32 are provided at each corner portion of the furnace end 12, and the blowing from the burner is performed while swirling. The virtual circle diameter ratio K1 (FIG. 5A) of the 1 burner 31 is set to be smaller than the virtual circle diameter ratio K2 (FIG. 5B) of the second burner. As a result, it is eccentric to the furnace wall direction so that the biomass flame 51 with a small particle size is wrapped with the biomass flame 52 with a large particle size (FIG. 5C), and the atmosphere near the wall surface is rich in high melting point particles. Thus, slugging may be avoided.
[0042]
[Sixth Embodiment]
A combustion apparatus according to the present embodiment will be described with reference to FIG.
As shown in FIG. 6, the combustion apparatus according to the present embodiment has a first burner 31 that supplies biomass 11 </ b> A having a large particle size at an upstream position (furnace upper side) of the combustion gas 30 of the furnace body 12. The second burner 32 for supplying the biomass 11B having a small particle size is provided at the upstream position (furnace lower portion side) of the combustion gas 30 of the furnace body 12.
[0043]
Thereby, the biomass 11B with a small particle size can rise and burn in the furnace.
Moreover, since the residence time until the biomass 11A with a large particle size falls to the furnace bottom part becomes long, a particle size becomes small gradually by biomass combustion radiant heat, and a part of fall biomass burns. Moreover, the fallen residue is fueled in a grate by hot air introduced separately.
[0044]
【The invention's effect】
According to the present invention, a combustion apparatus for supplying biomass into a furnace body and combusting it comprises a burner that mainly supplies biomass having a large particle size and supplies biomass having a small particle size into the furnace around the biomass. Therefore, biomass can be burned efficiently.
[Brief description of the drawings]
FIG. 1 is a schematic view of a combustion apparatus according to a first embodiment.
FIG. 2 is a schematic view of a combustion apparatus according to a second embodiment.
FIG. 3 is a schematic view of a combustion apparatus according to a third embodiment.
FIG. 4 is a schematic view of a combustion apparatus according to a fourth embodiment.
FIG. 5 is a schematic diagram showing a virtual circle diameter ratio and combustion state of biomass fuel.
FIG. 6 is a schematic view of a combustion apparatus according to a sixth embodiment.
FIG. 7 is a schematic view of a coal combustion apparatus.
[Explanation of symbols]
11 Biomass 11A Biomass with large particle size 11B Biomass with small particle size 12 Furnace body 13 Burner

Claims (12)

A combustion device for supplying biomass into a furnace body and burning it,
A combustion apparatus comprising a burner for supplying biomass having a small particle size into the furnace around a biomass having a large particle size. A combustion device for supplying biomass into a furnace body and burning it,
A combustion apparatus comprising: a first burner for supplying biomass having a large particle diameter into the furnace; and a second burner for supplying biomass having a small particle diameter into the furnace. In claim 2,
The first burner is provided at the combustion gas upstream position of the furnace body,
A combustion apparatus, wherein the second burner is provided at a position downstream of the combustion gas of the furnace body. In claim 2,
The first burner is provided at the combustion gas downstream position of the furnace body,
A combustion apparatus, wherein the second burner is provided at a combustion gas upstream position of the furnace body. In any one of Claims 2 thru | or 4,
A combustion apparatus comprising a classifying means for classifying biomass to be supplied to the first burner and the second burner. In any one of Claims 2 thru | or 5,
A combustion apparatus comprising: a plurality of stages of the first burner and the second burner, and an injection angle set so that the first and second burners are inclined with respect to a horizontal direction. In any one of Claims 2 thru | or 6,
Performing the swirling of the blowing of the first burner and the second burner,
A combustion apparatus characterized in that a virtual circle diameter ratio of the first burner is smaller than a virtual circle diameter ratio of the second burner. In any one of Claims 2 thru | or 7,
A combustion apparatus comprising a grate at the bottom of the furnace. In claim 8,
A combustion apparatus characterized in that a hot air supply port for supplying hot air into the furnace is provided between the grate and the lowermost burner at the bottom of the furnace. A combustion method for supplying biomass into the furnace body and burning it,
A combustion method characterized in that biomass having a large particle size is the center and biomass having a small particle size is supplied into the furnace and burned around the biomass. In claim 10,
A combustion method characterized in that the injection of biomass is performed while swirling, and a virtual circle diameter ratio by injection of biomass with a large particle size is smaller than a virtual circle diameter ratio by injection of biomass with a small particle size. A combustion method for supplying biomass into the furnace body and burning it,
A combustion method of supplying biomass having a large particle size from the first burner into the furnace and supplying biomass having a small particle size from the second burner into the furnace.

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