JP2012093024A - Biomass pellet crusher, and biomass-coal mixed-combustion system - Google Patents

Abstract

A biomass pellet pulverization apparatus and a biomass-coal mixed combustion system capable of easily pulverizing biomass pellets mixed and burned with coal.
SOLUTION: It has a moisture imparting means 13 for imparting moisture 12 to biomass pellets 11 and a coarse pulverizing means 14A for pulverizing biomass pellets 11A to which moisture 12 is imparted. The biomass pellet 11A to which moisture 12 has been added is temporarily stored in the hopper 16, and the moisture 12 spreads over the whole pellet or is self-disintegrated during the storage time, so that it can be easily pulverized by the pulverizing means 14B. It becomes. As a result, the co-firing rate with the coal 30 can be improved.
[Selection] Figure 1

Description

  The present invention relates to a biomass pellet pulverization apparatus and a biomass-coal mixed combustion system for pulverizing and pulverizing biomass pellets.

In recent years, CO ₂ emission reduction has been promoted from the viewpoint of global warming. In particular, fossil fuels such as coal and heavy oil are often used as fuel in combustion facilities such as power generation boilers, but these fossil fuels cause global warming due to the problem of CO ₂ emissions, and protect the global environment. Its use is being regulated from the viewpoint of In addition, from the viewpoint of depletion of fossil fuels, the development and commercialization of alternative energy resources are required. Therefore, as an alternative to fossil fuels, the use of fuel using biomass has been promoted. Biomass is an organic substance resulting from photosynthesis, and includes biomass such as wood, vegetation, crops, and moss. By converting this biomass into a fuel, the biomass can be effectively used as an energy source or an industrial raw material.

  From the viewpoint of highly efficient use of biomass, which is renewable energy, biomass is used as a fuel. One of the methods used as fuel is a method in which biomass solids are pulverized and pulverized and supplied to a pulverized coal-fired boiler for use as fuel. This is known as a single pulverization method in which coal and biomass are separately pulverized, and a mixed pulverization method in which coal and biomass are mixed and then pulverized. In any method, a biomass pulverization apparatus for pulverizing biomass solids is required. However, when an existing mill used in a conventional coal-fired boiler is used, due to capacity limitations of the existing mill, The mixed firing rate remained at about 3 cal% at the maximum.

  In order to pulverize conventional biomass to a particle size for a coal-fired boiler, a coal pulverizer is used. For example, biomass raw material is put into a pulverization table in a pulverizer and rotated in conjunction with the pulverization table. It is crushed and dried by a pulverizing roller to be classified. And the finely pulverized biomass is air-flow conveyed to the burner side (see Patent Document 1 and Patent Document 2).

JP 2004-347241 A JP 2009-291692 A

By the way, the biomass raw material is fibrous and soft, so the pulverization efficiency is poor, and the pulverization power is required to be about 5 to 10 times that of coal. However, the smaller the particle size of the pulverization raw material, the less power is required. It has been proposed to use biomass pellets obtained by solidifying and pelletizing small-sized biomass constituent particles (fine particles of several mm or less such as sawdust).
However, the biomass co-firing rate at existing power plants is limited to about 15 Cal% even in biomass pellets that are relatively easily pulverized, and more (20-30 Cal%) co-firing to reduce CO _2. Achieving rates is required.

  Biomass pellets absorb the moisture of coal in the pulverized raw material bunker and partly swell and disintegrate, but most of the pellets are supplied to the pulverizer (finishing mill) in the form of pellets. Since the pulverizer grinds more than the particle size necessary for combustion, more pulverization power is required.

  In view of the above problems, an object of the present invention is to provide a biomass pellet pulverizing apparatus and a biomass-coal mixed combustion system that can easily pulverize biomass pellets mixed and burned with coal.

  1st invention of this invention for solving the subject mentioned above has the moisture provision means which provides a moisture to a biomass pellet, and the grinding | pulverization means which grind | pulverizes the biomass pellet to which the moisture was provided to a fine powder, In the biomass pellet mill.

  A second invention is the biomass pellet pulverizing apparatus according to the first invention, wherein the pulverizing means includes a coarse pulverizing means and a fine pulverizing means.

  According to a third aspect of the present invention, there is provided a biomass pellet pulverizing apparatus according to the first or second aspect of the invention, further comprising a mixing unit that mixes coal with the biomass pellets to which moisture has been imparted by the moisture imparting unit.

  A fourth invention is the biomass pellet pulverizing apparatus according to the second invention, wherein the pulverizing means is mixed with coal and pulverized.

  5th invention stores the conveying means which conveys the stored coal and the stored biomass pellet, and the mixed coal-biomass pellet mixture for a predetermined time, and stores the moisture of the coal into the biomass pellet. A hopper that swells biomass pellets while being transferred, a coarse pulverization unit that coarsely pulverizes the mixed / swelled material from the hopper, and a fine pulverizer that finely pulverizes the coarsely pulverized product of the coarse pulverization unit. It is in the biomass pellet pulverizer.

  According to a sixth aspect of the present invention, there is provided the biomass pellet pulverizing apparatus according to the fifth aspect of the present invention, wherein the transport means has a moisture imparting means.

  A seventh invention is the fifth or sixth invention, wherein the separating means for separating the finely pulverized product pulverized by the coarse pulverizing means, and the conveying line for conveying the finely pulverized product separated by the separating means to the boiler side. It is in the biomass pellet crusher characterized by having.

  According to an eighth aspect of the invention, any one of the first to seventh biomass pellet pulverization apparatuses, coal pulverization means for pulverizing only the coal raw material, fine powder pulverized by the pulverization means of the biomass pulverization apparatus, and pulverization by the coal pulverization means A biomass-coal co-firing system comprising a boiler furnace to which the coal powder is supplied.

  According to the present invention, since it has moisture imparting means for imparting moisture to the biomass pellets and coarse pulverizing means for pulverizing the biomass pellets imparted with moisture, temporarily storing the biomass pellets imparted with moisture, During the storage time, moisture spreads throughout the pellet or self-disintegrates, so that fine pulverization by the fine pulverization means becomes easy. As a result, the co-firing rate with coal can be improved.

FIG. 1 is a schematic diagram of a biomass pellet crusher according to the first embodiment. FIG. 2 is a schematic view of a biomass pellet crusher according to the second embodiment. FIG. 3 is a schematic view of a biomass pellet crusher according to the third embodiment. FIG. 4 is a schematic diagram of a biomass pellet crusher according to the fourth embodiment. FIG. 5 is a schematic diagram of a biomass pellet crusher according to the fifth embodiment. FIG. 6 is a graph showing the mixing elapsed time of coal and biomass pellets and the moisture change of the biomass pellets. FIG. 7 is a schematic diagram of a biomass / coal mixed combustion system including a boiler furnace according to a sixth embodiment.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

A biomass pellet crusher according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a biomass pellet crusher according to the first embodiment.
As shown in FIG. 1, the biomass pellet crusher 10A according to the present embodiment includes a moisture applying unit 13 that applies moisture 12 to the biomass pellet 11 and a coarsely pulverizing unit 14A that pulverizes the biomass pellet 11A to which moisture 12 has been applied. It has.

  Here, in this invention, the biomass pellet 11 means what pelletized the biomass constituent particle | grains by which the biomass raw material was cut | judged (small particle | grains, such as sawdust, several mm or less) solidified. The moisture content of the biomass pellet 11 is 10% or less.

  The biomass pellet 11 is supplied from the biomass pellet storage facility 15 to the hopper 16 via the first conveying means 17. In the present embodiment, the moisture applying means 13 in the middle of the first conveying means 17 Moisture 12 is given to the biomass pellets 11.

In this embodiment, the biomass pellets 11A to which moisture 12 has been applied are temporarily stored (for example, about 1 to 2 hours) in the hopper 16, and the moisture 12 spreads throughout the pellets during the storage time or is self-disintegrated. Yes.
Thereafter, in the coarsely pulverizing means 14A, the wet biomass pellets 11A are easily coarsely pulverized, and the coarsely pulverized coarsely pulverized biomass pellets 11B are sent to the pulverized raw material bunker 19 by the second conveying means 18, from which finely pulverized means 14B, where it is pulverized.

  In the fine pulverizing means 14B, the coarsely pulverized biomass pellets 11B fall from the upper part of the pulverizing roller 21 onto the pulverizing table 22 via the biomass supply pipe 23. The dropped biomass pellet 11 </ b> B moves from the central portion to the outer peripheral side by a centrifugal force generated by the rotation of the grinding table 22. In the meantime, it is sandwiched between the pulverizing roller 21 and the pulverizing table 22, and pulverized into fine biomass (fine powder) 11C having the optimum size for combustion. The coarse powder and fine powder that have been raised by the blowing gas 24 on the outer periphery of the pulverization table 22 are mixed, but the coarse powder is separated by the classifier 25 installed at the upper part of the fine pulverization means 14B, and the fine powder biomass 11C is burner of the boiler furnace 26. Supplied by the third conveying means 27. The coarse particles separated by the classifier 25 are dropped, return to the center of the crushing table 22, and finely pulverized again by the crushing roller 21.

In the case of simultaneously mixing and pulverizing coal, a coal supply line 33 for supplying the coal 30 from the coal storage facility 31 is provided adjacent to the biomass supply pipe 23 of the pulverizing means 14B.
This enables mixing and pulverization of the biomass pellets to which moisture has been applied and the coal 30. The coal supply line 33 may be installed in the biomass supply pipe 23.

In this embodiment, the pulverizing means 14 includes a coarse pulverizing means 14A and a fine pulverizing means 14B.
As the coarse pulverizing means 14A, for example, a hammer mill or an impact mill can be used. Moreover, as the fine grinding means 14B, for example, a rotary mill can be used.
When the swelling of the biomass pellet 11 is progressing due to moisture application, the coarsely pulverizing means 14A is omitted as the pulverizing means 14, and the wet biomass pellet 11A is finely pulverized using only the finely pulverizing means 14B. It may be.

  As described above, in the mixed pulverization of the coal 30 and the biomass pellet 11, the coarse pulverization means 14A for coarse pulverization (pulverization) and the fine pulverization means 14 for finish pulverization are provided. When supplying the pellets 11, moisture 12 is given, and the wet biomass pellets 11 A to which moisture has been given is stored in the hopper 16 for a predetermined time. So that it gets wet.

  FIG. 6 is a graph showing the mixing elapsed time of the coal 30 and the biomass pellet 11 and the moisture change of the biomass pellet 11. As shown in FIG. 6, the biomass pellet 11 swells by absorbing water to about 10% of total water in about 1 hour. As a result of this swelling, the binding force of the biomass pellets 11 becomes extremely small, so that it can be crushed to a particle shape before binding with low power in the pulverization by the coarse pulverization means 14A.

  Further, since the biomass supplied to the fine pulverizing means 14B, which is the finish pulverization, is small enough so as not to interfere with the boiler combustion (less than several mm), the pulverization power in the fine pulverizing means 14B may be greatly reduced. it can. As a result, the required power per pulverizer can be reduced.

  Furthermore, in the existing power plant, it is difficult to modify the boiler building, and it is difficult to install the coarse grinding means 14A between the grinding raw material bunker and the fine grinding means 14B. It will be possible to install a crusher outdoors.

As described above, according to this embodiment, the mixed combustion ratio with the conventional coal is about 15 Cal%, but it becomes possible to achieve a mixed combustion rate of, for example, about 20 to 30 Cal%, which contributes to CO ₂ reduction. be able to.

A biomass pellet crusher according to an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a schematic view of a biomass pellet crusher.
As shown in FIG. 2, the biomass pellet crusher 10B according to the present embodiment is configured such that in the biomass pellet crusher 10A according to the first embodiment, before the coal 30 is supplied to the fine pulverizer 14B, Coal 30 is mixed with the applied biomass pellets 11A.
In the present embodiment, a coal supply line 33 for supplying the coal 30 is provided in the middle of the first conveying means 17 that conveys the biomass pellets 11A to which moisture has been imparted.

As a result, when the biomass pellets 11 </ b> A to which moisture is applied and the coal 30 are mixed and contacted in the hopper 16, the moisture in the coal 30 is further absorbed and swollen. As a result of this swelling, the binding force of the biomass pellets becomes extremely small, so that it can be crushed to a particle shape before binding with low power in the pulverization by the coarse pulverization means 14A.
In the present embodiment, when the biomass pellet 11 is swollen, water in the coal 30 can be used, so that the supply amount of the water 12 can be reduced as compared with the first embodiment.

A biomass pellet crusher according to an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a schematic view of a biomass pellet crusher.
As shown in FIG. 2, the biomass pellet pulverization apparatus 10C according to the present example is a finely pulverized product of 1 mm or less of the biomass pellets coarsely pulverized by the coarse pulverization means 14A in the biomass pellet pulverization apparatus 10B of Example 1. Separation means 40 for separating the pulverized biomass 11C is provided. Since the pulverized biomass 11C separated by the separation means 40 is 1 mm or less, the combustion in the boiler furnace 26 becomes possible as it is. Accordingly, the finely powdered biomass 11C is supplied by the fourth transport line 41 to the third transport means 27 for transporting the finely powdered biomass 11C pulverized by the fine pulverization means 14B to the burner.

The separation means 40 can be separated using, for example, a cyclone or a sieve, and a single-stage vibrating sieve is used in this embodiment.
Here, the single-stage vibrating sieve is provided with a sieve that passes through 1 C or less of pulverized biomass 1C.

  The pulverized material coarsely pulverized by the coarsely pulverizing means 14A is separated by the separating means 40, and the finely divided fine biomass 11C is directly supplied to the boiler furnace 26 side, and the coarsely pulverized biomass pellets 11B having a particle size larger than that required for the finely pulverizing means 14B. Can only supply. Thereby, since the setting of the fine pulverizing means 14B can be taken roughly, excessive pulverization can be prevented.

A biomass pellet crusher according to an embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a schematic view of a biomass pellet crusher.
As shown in FIG. 4, in the biomass pellet crusher 10D according to the present embodiment, the pulverized product 11B coarsely pulverized by the coarse pulverization means 14A in the biomass pellet pulverizer 10C of Example 3 is a fine pulverized product of 1 mm or less. In this case, the boiler or furnace 26 is supplied as it is through the fourth transport line 41.
Thereby, the separating means 40 becomes unnecessary, and the apparatus can be simplified.

A biomass pellet crusher according to an embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a schematic view of a biomass pellet crusher.
As shown in FIG. 5, the biomass pellet crushing apparatus 10E according to the present embodiment deletes the moisture applying unit 13 in Example 1 and mixes the biomass pellet 11 and the coal 30 on the first transport unit 17. While transporting.
The mixed coal / biomass pellet mixture 34 is stored for a predetermined time, and a coal / biomass mixed hopper 35 that swells the biomass pellet 11 while transferring the moisture of the coal 30 to the biomass pellet 11 is provided.

The mixed / swelled material stored in the coal / biomass mixed hopper 35 for a predetermined time is roughly pulverized by the coarse pulverizing means 14A.
Thereafter, the coarsely pulverized product 34A coarsely pulverized by the coarse pulverizing means 14A is sent to the pulverized raw material bunker 19 by the second conveying means 18, and is supplied from here to the finely pulverized means 14B, where it is finely pulverized.
The finely pulverized product 34B finely pulverized by the fine pulverizing means 14B is supplied by the third conveying means 27 to the burner of the boiler furnace 26.

  In this embodiment, since only the moisture that the coal 30 itself holds to wet the biomass pellets 11 with water is used, it is not necessary to separately install a moisture applying means as in the first embodiment.

  If necessary, when the moisture content of the biomass pellets 11 is low, a separate moisture imparting unit may be provided and added separately from the coal-derived moisture to promote the swelling action by moisture.

A biomass / coal mixed combustion system including a boiler furnace according to Example 6 of the present invention will be described with reference to the drawings. FIG. 7 is a schematic view of a biomass-coal mixed combustion system including a boiler furnace according to the present embodiment.
As shown in FIG. 7, the biomass pellet pulverization apparatus 10 </ b> A according to the first embodiment described above is applied to the biomass / coal mixed combustion system including the boiler furnace according to the present embodiment.
In addition, since it is the same also about biomass pellet grinding | pulverization apparatuses 10B-E of Examples 2-5, it abbreviate | omits.
As shown in FIG. 7, the biomass-coal mixed combustion system according to the present embodiment stores biomass pellets 11 which are biomass solids obtained by primary crushing (coarse crushing) to a predetermined particle size or less and drying and molding as necessary. A biomass pellet storage facility 15, a pulverized raw material bunker 19 that receives biomass pellets 11 </ b> A supplied with biomass pellets 11 and is provided with moisture from the moisture applying means 13, and a pulverizing means 14 </ b> B that finely pulverizes the biomass pellets 11 </ b> A. Obtained by the pulverized biomass pellet pulverizer 10A, the coal pulverizers 52a and 52b provided with the hoppers 51a and 51b for receiving the coal 30, and the finely pulverized biomass 11C obtained by the biomass pellet pulverizer 10A and the coal pulverizers 52a and 52b. Boiler furnace 26 to which supplied coal powder 53 is supplied; Equipped with a.
The finely powdered biomass 11C and the coal powder 53 pulverized by the biomass pellet pulverizing apparatus 10A are supplied to the boiler furnace 26, and the fine powder (only the biomass powder or a mixture of the pulverized biomass and the coal powder) 11C and coal are supplied to the boiler furnace 26. The powder 53 is mixed and burned.

The boiler furnace 26 is provided with a fuel supply nozzle and a burner cooperating therewith. The combustion exhaust gas generated by the combustion heats the heat transfer tube 61 arranged in the furnace and is sent to the flue. An air heater (AH) 62 is disposed in the middle of the flue provided at the furnace outlet of the furnace body, and the combustion exhaust gas that has passed through the air heater 62 is exhaust gas treatment equipment such as an ash collector (not shown). And then released into the atmosphere.
The high-temperature air 64 generated by heating the outside air 63 by the air heater 62 is supplied to the coal pulverizers 52 a and 52 b and used for drying the coal 30. Further, a part 65 of the combustion exhaust gas is supplied to the biomass crusher 10A by the induction fan 66 and used for classification and drying of the biomass.

As described above, since the biomass pellet pulverization apparatus according to the present invention is used as a system, the pulverization of the biomass pellets becomes good, so even when the pulverized product is directly introduced into the combustion apparatus and combusted, the combustion performance is improved. Stable combustion is possible without lowering.
In addition, since the total amount of the pushed-in gas does not change from the conventional amount, there is no fluctuation in the primary air, and the biomass pulverizer can be operated stably within the range of the air amount required in the combustion facility. Is possible.

  As described above, according to the biomass pellet pulverization apparatus and the biomass / coal co-firing system according to the present invention, by providing moisture, self-disintegration is possible, and pulverization by the pulverization means is facilitated. It can contribute to the improvement of the mixed firing rate.

10A to 10E Biomass pellet crusher 11 Biomass pellet 11A Wet biomass pellet 11B Coarse pulverized biomass pellet 11C Fine powder biomass (fine powder)
DESCRIPTION OF SYMBOLS 12 Water | moisture content 13 Water | moisture-content provision means 14A Coarse grinding | pulverization means 14B Fine grinding | pulverization means 15 Biomass pellet storage equipment 16 Hopper 17 1st conveyance means 18 2nd conveyance means 27 3rd conveyance means

Claims (8)

Moisture applying means for applying moisture to the biomass pellets;
A biomass pellet pulverizing apparatus comprising a pulverizing means for pulverizing biomass pellets to which moisture has been added into fine powder. In claim 1,
A biomass pellet pulverizing apparatus, wherein the pulverizing means comprises coarse pulverizing means and fine pulverizing means. In claim 1 or 2,
A biomass pellet pulverizing apparatus comprising: mixing means for mixing coal with biomass pellets to which moisture has been imparted by the moisture imparting means. In claim 2,
A biomass pellet pulverizing apparatus, wherein the pulverizing means mixes and pulverizes coal. Conveying means for conveying the stored coal and the stored biomass pellets while mixing them;
A hopper that swells the biomass pellets while storing the mixed coal / biomass pellet mixture for a predetermined time and transferring the moisture of the coal to the biomass pellets;
Coarse pulverizing means for coarsely pulverizing the mixed / swelled material from the hopper;
A biomass pellet pulverizing apparatus, comprising: a fine pulverizer for finely pulverizing the coarsely pulverized product of the coarse pulverizing means. In claim 5,
A biomass pellet crusher characterized in that the conveying means has a moisture imparting means. In claim 5 or 6,
Separating means for separating the finely pulverized product crushed by the coarse pulverizing means;
A biomass pellet pulverizing apparatus comprising a conveying line for conveying the finely pulverized product separated by the separating means to the boiler side. A biomass pellet pulverizing apparatus according to any one of claims 1 to 7,
Coal pulverizing means for pulverizing only the coal raw material;
A biomass-coal co-firing system comprising a boiler furnace to which fine powder pulverized by a pulverizing means of the biomass pellet pulverizing apparatus and coal powder pulverized by a coal pulverizing means are supplied.

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