JP6245436B2 - Boiler device and biomass fuel supply method to boiler - Google Patents

Description

  The present invention relates to a boiler apparatus that generates steam by burning biomass fuel obtained by refining biomass, and a method for supplying biomass fuel to a boiler.

Conventionally, as a thing similar to the boiler apparatus which burns the above-mentioned biomass fuel, there exists a power generation system described in patent document 1, and a biomass pre-processing unit described in patent document 2, for example.
A power generation system described in Patent Document 1 includes a waste treatment device that makes organic waste contact with water vapor and discharges it as dry matter, and a coal boiler that burns dry matter discharged from the waste treatment device together with coal. In this power generation system, water is evaporated by supplying a part of the water vapor obtained in the coal boiler to the waste treatment device and contacting with the organic waste, thereby making the organic waste fine particles. The product is discharged as a dry product.

  On the other hand, the biomass pretreatment unit described in Patent Document 2 includes a biomass pulverization apparatus and a biomass feeder that supplies biomass to the biomass pulverization apparatus. In this biomass pretreatment unit, a part of boiler gas is supplied to the biomass feeder. Is introduced to embrittle the biomass while heating it.

JP 2010-101503 A JP 2013-088033 A

  However, in the former power generation system, organic waste can be discharged as dry matter, but when the organic waste is fine and difficult to grind easily, a waste treatment device In addition to this, a pulverizer and power for operating the pulverizer are further required.

  On the other hand, even in the latter biomass pretreatment unit, the biomass can be embrittled while being heated, but in order to refine the biomass to a size that can be combusted in a boiler, the embrittled biomass is used as a biomass crusher. It is necessary to go to.

  In other words, in both cases of the former power generation system and the latter biomass pretreatment unit, apart from drying, facilities and processes for pulverizing organic waste and biomass to a size that can be combusted in a boiler are necessary. Accordingly, there is a problem that the equipment cost and the power cost are high, and it has been a conventional problem to solve this problem.

  The present invention has been made paying attention to the above-described conventional problems, and can be used as a fuel while generating biomass fuel by pulverizing and drying biomass with less energy, and as a result, An object of the present invention is to provide a boiler device and a method for supplying biomass fuel to the boiler that can reduce the operating cost of the boiler.

A first aspect of a boiler apparatus according to the present invention is a boiler that burns biomass fuel or mixes and burns the biomass fuel and coal to generate steam, and the biomass is dried and refined to produce the boiler. The biomass fuel supply unit that supplies the fuel as biomass fuel, the high-pressure turbine that is rotated by steam generated by the combustion of the biomass fuel in the boiler or the mixed combustion of the biomass fuel and coal, and the high-pressure turbine comprising a reheater for reheating steam after for the middle and low pressure turbine work, the biomass fuel supply unit introduces a part of the steam back to the high pressure turbine to the reheater by rotating Thus, the biomass fuel is generated by steam explosion of the biomass.

Moreover , the 2nd aspect of this invention introduces at least any one of the vapor | steam which generate | occur | produces in the said boiler, and exhaust gas, and dries the refined | miniaturized biomass fuel produced | generated in the said biomass fuel supply part Classifying the refined biomass fuel dried by the dryer and the dryer, the biomass fuel refined to a size that does not exceed the threshold of the size that can be burned out by the boiler to the boiler As a configuration comprising a classifier for supplying and repeatedly returning the biomass fuel refined to a size equal to or larger than the size threshold to the biomass fuel supply unit until the biomass fuel is refined to a size not exceeding the size threshold Yes.

  Here, if the size of the refined biomass fuel supplied to the boiler is, for example, a piece of wood, if it is set large, it will take a lot of time to burn out or remain unburned. It takes a lot of energy to make it finer. That is, it is desirable that the threshold value of the size of the piece of wood that can be burned out by the boiler is set to a magnitude that is comparable to the pulverized coal fuel and the combustion time when the pulverized coal fuel is supplied to the boiler of the coal fired boiler apparatus.

On the other hand, the biomass fuel supply method to the boiler according to the present invention includes a boiler that burns biomass fuel, or a mixture that burns the biomass fuel and coal to generate steam, and refines biomass to produce biomass in the boiler. A biomass fuel supply unit that supplies fuel, a high-pressure turbine that is rotated by steam generated in the boiler, and a reheater that reheats steam used for work of the high-pressure turbine for work of a medium- and low-pressure turbine A method of supplying the biomass fuel to the boiler of the provided boiler device, wherein the biomass is supplied to the biomass fuel supply unit, and the biomass fuel is burned, or the biomass fuel and coal are mixed and burned. some of the steam generated in a boiler by rotating the high pressure turbine passed back to the reheater Was introduced, after the biomass to generate the biomass fuel by steam explosion, the biomass fuel produced by steam explosion has a configuration supplied to the boiler.

  In the boiler apparatus and the method of supplying biomass fuel to the boiler according to the present invention, steam explosion refers to introducing biomass into a biomass fuel supply unit (explosive crusher) and conducting high-temperature steam and holding it at a high pressure, followed by rapid decompression. By this, it means an operation of explosively expanding the steam contained in the compressed steam and the biomass and finely destroying the biomass from the inside without being caused by an external mechanical action. In this expansion process, since the water inside the biomass is volatilized at the same time, drying is also performed at the same time.

  In the boiler apparatus and the biomass fuel supply method to the boiler according to the first aspect of the present invention, the biomass fuel is supplied by being burned alone after the biomass is supplied to the biomass fuel supply unit, or the biomass fuel and When a portion of the high-temperature steam generated in the boiler by burning coal together is introduced into the biomass fuel supply section and held at a high pressure, and then rapidly depressurized in the biomass fuel supply section, the biomass is generated by steam explosion. The biomass fuel is generated by being pulverized into pieces.

  At this time, the amount of steam introduced into the biomass fuel supply unit is a few percent of the steam generated in the boiler device, as compared to the case of pulverizing biomass using electric power obtained by converting the steam energy of the boiler. Therefore, biomass fuel can be generated with extremely little energy.

In this case, by introducing a part of the steam that will be subjected to work in-pressure turbine to rotate the high pressure turbine (reheat steam) biomass fuel supply unit, both the temperature and pressure to provide the rotation of the high pressure turbine Compared with the case where a part of the higher steam is introduced into the biomass fuel supply unit, the efficiency of energy utilization is improved by the amount of steam having a lower temperature and pressure.

Moreover , like the boiler apparatus which concerns on a 2nd aspect, the dryer which dries the refined biomass fuel produced | generated in a biomass fuel supply part, and the magnitude | size which can be burned out in a boiler by classifying the dried biomass fuel When a configuration equipped with a classifier that supplies biomass fuel refined to a size that does not exceed the threshold value to the boiler is adopted, the biomass fuel can be dried and necessary and sufficiently burned. Biomass fuel of a size suitable for efficiency improvement can be supplied to the boiler.

  In the boiler apparatus according to the present invention, the biomass fuel can be used as a fuel while pulverizing the biomass with less energy than before to generate the biomass fuel, thereby realizing a reduction in energy consumption for power generation. This is a very good effect.

BRIEF DESCRIPTION OF THE DRAWINGS It is schematic structure explanatory drawing which shows the boiler apparatus by one Example of this invention. It is composition explanatory drawing which shows the principal part of the boiler apparatus by the other Example of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a boiler apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the boiler apparatus 1 includes a coal-fired boiler (combustor) 2 including a furnace 2a, a superheater 2b in a rear heat transfer section, a reheater 2c, and a coal-saving section 2d. A denitration unit 4, an air heater 5, a dust collector 6, an induction fan 7, a heat exchanger 8, a desulfurization unit 9, and a push-in fan 10 are sequentially arranged in the flue gas treatment flue 3 from the coal-saving unit 2d to the chimney P. It is made up of.

  The air heater 5 warms the external air introduced by the pushing fan 11 with the heat of the exhaust gas discharged from the denitration unit 4 and sends it as combustion air to the burner unit 2e of the coal-fired boiler 2, and the heat exchanger 8 is an induction fan Heat exchange is performed between the exhaust gas after passing through the dust collector 6 guided by 7 and the exhaust gas after passing through the desulfurization section 9 introduced by the pushing fan 10.

  The coal-fired boiler 2 of the boiler device 1 is supplied with coal C pulverized by the mill 20 as pulverized coal fuel, and the pulverized coal fuel is introduced by the pushing fan 11. Together with the combustion air, the burner part 2e is introduced into the furnace 2a of the coal-fired boiler 2 for combustion.

  Steam generated by the combustion of pulverized coal fuel in the coal-fired boiler 2 of the boiler device 1 is sent from the superheater 2b of the rear heat transfer section to the high-pressure turbine 22 via the pipe 21, and the work of the high-pressure turbine 22 is performed. After being provided, it is returned to the reheater 2c of the rear heat transfer section through the pipe 23 and heated again. The steam that has been heated again is sent to the intermediate / low pressure turbine 25 via the pipe 24 and is used for work of the intermediate / low pressure turbine 25, and then the coal fired boiler via the pipe 26 and the condenser 27. Return to 2.

  Moreover, this boiler apparatus 1 is provided with the crusher (biomass fuel supply part) 30 which refines | miniaturizes biomass B and produces biomass fuel. A branch pipe 28 branched from the pipe 23 is connected to the blasting machine 30, and a part of the steam at 200 to 300 ° C. returned to the reheater 2 c of the rear heat transfer section is used for work by the high-pressure turbine 22. Has been introduced.

  In the blasting machine 30, the steam introduced through the branch pipe 28 is held at a high pressure (about 4.5 MPa) and then rapidly depressurized, whereby the steam contained in the compressed steam and the biomass B is removed. The biomass B is explosively expanded to break down the biomass B finely. Like the pulverized coal fuel, the biomass fuel produced thereby is burned together with the combustion air introduced by the pushing fan 11 and the burner portion 2e. Is inserted into the furnace 2a of the coal fired boiler 2 and burned.

In the boiler apparatus 1 according to this embodiment, first, biomass B is charged into the explosive device 30.
Next, reheat steam out of the high-temperature steam generated in the coal fired boiler 2 by the combustion of pulverized coal fuel and biomass fuel (the reheater 2c in the rear heat transfer section of the coal fired boiler 2 by rotating the high pressure turbine 22) A part of the steam that returns to (5) is introduced into the explosive device 30 and held at a high pressure for a predetermined time.

  Thereafter, when the decompressor 30 is rapidly decompressed, the biomass B is shattered by steam explosion and biomass fuel is generated. At this time, the amount of steam introduced into the disrupter 30 is determined by the boiler device. 1 is a few percent of the total steam generated, and biomass fuel can be produced with very little energy compared to the case where the biomass B is pulverized using electric power obtained by converting the steam energy of the coal-fired boiler 2. It will be.

  In this embodiment, a part of the reheated steam is introduced into the blasting machine 30 via the branch pipe 28, so that a part of the steam used for the rotation of the high-pressure turbine 22 is introduced into the blasting machine 30. Compared to the case, energy efficiency can be further improved.

  Therefore, when the amount of energy (energy) necessary for obtaining biomass fuel through two processes of drying and crushing is compared with the amount of energy required for the boiler apparatus 1 according to this embodiment to obtain biomass fuel. The amount of energy required to obtain biomass fuel through two processes of drying and crushing is 2 to 3 MJ (in terms of 1 kg of biomass fuel (14 MJ / kg to 17 MJ / kg) generated from woody biomass. It is estimated that (for drying) +1.5 to 2 MJ (for crushing) is necessary, whereas the amount of energy required for the boiler apparatus 1 according to this embodiment to obtain biomass fuel is 1 to 1. It is estimated that only 5MJ is sufficient.

  In addition, when biomass fuel is obtained through two processes, drying and crushing, electric power is required for the use of a motor or the like for crushing, and the amount of heat necessary to obtain this electric power is about 2.5 times that amount. Therefore, an energy amount of 2.5 to 3.8 MJ is necessary for substantial crushing.

  Therefore, the amount of energy required for the boiler apparatus 1 according to this embodiment using the steam generated in the coal-fired boiler 2 to obtain the biomass fuel is larger than that in the case of obtaining the biomass fuel through two processes of drying and crushing. It can be estimated that it is significantly less.

  FIG. 2 shows a boiler apparatus according to another embodiment of the present invention.

  As shown in part in FIG. 2, the boiler device 1 </ b> A is different from the boiler device 1 of the previous embodiment by introducing a part of the steam generated in the coal fired boiler 2 through the branch pipe 28. It is in the point provided with the classifier 32 which classifies the biomass B dried by this dryer 31 and the dryer 31 which dries the refined biomass B produced | generated by the blasting machine 30, and another structure is the previous implementation. It is the same as the boiler apparatus 1 of the example.

  In this case, the classifier 32 that classifies the biomass B dried by the dryer 31 pushes in the biomass B that has been refined to a size that does not exceed the threshold value that can be burned out in the predetermined coal-fired boiler 2. The combustion air introduced by the fan 11 (not shown in FIG. 2) is introduced into the furnace 2a through the burner portion 2e, and the biomass B refined to a size equal to or larger than the size threshold is not exceeded. It is repeatedly returned to the blasting machine 30 until it is refined in size.

  Here, when the size of the refined biomass B supplied to the coal-fired boiler 2 is, for example, a piece of wood, as described above, if it is set large, it takes a lot of time to burn out or remains unburned. On the other hand, if a small value is set, a large amount of energy is required to reduce the size to that size. Therefore, the threshold of the size of the piece of wood is supplied to the coal burning boiler 2 together with the pulverized coal fuel as in this embodiment In this case, it is desirable that the combustion time be approximately the same as that of the pulverized coal fuel (approximately 1 mm depending on the type of biomass B).

  In the boiler apparatus 1A according to this embodiment, the biomass B can be dried as necessary and sufficiently, and the biomass B having a size suitable for improving the combustion efficiency can be supplied to the coal burning boiler 2.

  In the dryer 31 of the boiler apparatus 1A according to this embodiment, a part of the steam generated in the coal fired boiler 2 is introduced to dry the refined biomass B generated by the explosive machine 30. As indicated by phantom lines in FIG. 2, exhaust gas generated in the coal fired boiler 2 may be introduced via the pipe 33 to dry the refined biomass B generated by the explosive machine 30.

  The structure of the boiler apparatus which concerns on this invention, and the biomass fuel supply method to a boiler are not limited to an above-described Example.

1,1A Boiler 2 Coal-fired boiler (combustor)
2c reheater 22 pressure turbines
25 medium and low-pressure turbines
30 explosion machine (biomass fuel supply part)
31 Dryer 32 Classifier B Biomass C Coal

Claims (3)

A boiler that generates steam by burning biomass fuel or by mixing and burning the biomass fuel and coal;
A biomass fuel supply unit that refines biomass and supplies the boiler with biomass fuel;
A high-pressure turbine rotated by steam generated by combustion of the biomass fuel in the boiler or mixed combustion of the biomass fuel and coal ;
A reheater for reheating the steam after being used for the work of the high pressure turbine for the work of the medium / low pressure turbine ;
The biomass fuel supply unit, by introducing a part of the steam back to the high pressure turbine to the reheater by rotating, boiler apparatus the biomass to produce the biomass fuel by steam explosion. At least one of steam generated in the boiler and / or exhaust gas is introduced to dry the refined biomass fuel generated in the biomass fuel supply unit, and the dryer is dried by the dryer The refined biomass fuel is classified, and the biomass fuel refined to a size that does not exceed the size threshold that can be burned out by the boiler is supplied to the boiler and the size is equal to or larger than the size threshold. 2. The boiler apparatus according to claim 1, further comprising a classifier that repeatedly returns the biomass fuel finely refined to the biomass fuel supply unit until the biomass fuel is refined to a size that does not exceed the size threshold. A boiler that burns biomass fuel or mixes and burns the biomass fuel and coal to generate steam, a biomass fuel supply unit that refines biomass and supplies it to the boiler as biomass fuel, and steam generated in the boiler And a method of supplying the biomass fuel to the boiler of a boiler apparatus comprising a high-pressure turbine rotating by a reheater and a reheater that reheats steam used for the work of the high-pressure turbine for work of a medium- and low-pressure turbine. There,
The biomass is fed into the biomass fuel supply unit, and is generated in the boiler by combustion of the biomass fuel or mixed combustion of the biomass fuel and coal, and the high pressure turbine is rotated and returned to the reheater. The biomass fuel supply method to the boiler which introduce | transduces a part of steam which produces | generates the said biomass fuel by carrying out steam explosion of the said biomass, and supplies the said biomass fuel produced | generated by steam explosion to the said boiler.

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