JP2020200411A - Method of producing biomass solid fuel, moisture adjustment method of biomass solid fuel, and biomass solid fuel - Google Patents

Abstract

To provide a method for producing biomass solid fuel that does not easily dust-explode.SOLUTION: A method of producing biomass solid fuel obtainable by forming a biomass-containing feedstock into a lump, comprising a step in which moisture is added to at least a biomass feedstock or a lump, thereby making the moisture content of the biomass solid fuel to 5 to 25 mass%.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a biomass solid fuel, a method for adjusting the water content of the biomass solid fuel, and a biomass solid fuel.

In recent years, biomass fuels have been studied to reduce CO ₂ emissions, which are a cause of global warming. Construction of a biomass-fired power plant is actually underway.
For example, Patent Document 1 discloses a method for producing a solid fuel, which comprises a step of mechanically compressing and dehydrating a biomass raw material containing wood. In the method for producing solid fuel described in Patent Document 1, the weight ratio of the biomass raw material passing through the sieve having a mesh size of 6.4 mm increases by only 5.0% or less before and after compression, and the biomass after compression increases. It is disclosed that the low calorific value of is 2100 kcal / kg or more.

Biomass fuel is expected to be used in the same manner as coal, although it has a lower calorific value than coal, which is a typical solid fuel.
For example, Patent Document 2 provides a coal crusher that crushes coal to obtain coal powder, a biomass crusher that crushes biomass to obtain biomass powder, and the coal powder and biomass powder. A biomass / coal co-firing system is disclosed, which comprises a boiler furnace and mixes and crushes the biomass while adding additives to the biomass when crushing by the biomass crushing apparatus.

Japanese Unexamined Patent Publication No. 2018-095685 Japanese Unexamined Patent Publication No. 2012-132602

Biomass fuel is usually solidified and transported in chunks such as pellets or briquettes. However, when transporting biomass fuel, dust may be generated due to mechanical impact or the like. This dust scatters in the air and reaches a certain concentration, and there is an ignition source such as static electricity there, and if the conditions are met, there is a possibility of causing a dust explosion.
On the other hand, the FIT system (feed-in tariff system for electricity) and the law that obliges electric power companies to expand the use of renewable energy require that the amount of biomass fuel used in power plants be increased. In order to meet such demands for increasing the amount of biomass fuel used, it is required to further improve the safety of biomass fuel.
An object of the present invention is to provide a method for producing a biomass solid fuel that is less likely to cause a dust explosion, a method for adjusting the water content of the biomass solid fuel, and a biomass solid fuel.

According to one aspect of the present invention, it is a method for producing a biomass solid fuel obtained by molding a biomass raw material containing biomass into a lump, and the water content of the biomass solid fuel is 5% by mass or more and 25% by mass or less. A method for producing a biomass solid fuel is provided, which comprises a step of adding water to at least one of the biomass raw material and the lumpy substance.

In the method for producing a biomass solid fuel according to one aspect of the present invention, the step of adding water is a step of immersing the biomass raw material in water, a step of spraying water on the biomass raw material, or a step of humidifying the biomass raw material. The process of storing in space is preferable.

In the method for producing a biomass solid fuel according to one aspect of the present invention, the step of adding water is a step of immersing the lump in water, a step of spraying water on the lump, or a step of humidifying the lump. It is preferable that the process is to store in a space.

In the method for producing a biomass solid fuel according to one aspect of the present invention, the biomass is at least one selected from the group consisting of woody biomass, vegetation-based biomass, crop residue-based biomass, and palm coconut biomass. preferable.

In the method for producing a biomass solid fuel according to one aspect of the present invention, it is preferable that the biomass is a powder and the major axis diameter of the powder is 5 mm or less.

In the method for producing a biomass solid fuel according to one aspect of the present invention, the lump is preferably pellets or briquettes.

In the method for producing a biomass solid fuel according to one aspect of the present invention, the biomass raw material preferably further contains coal.

In the method for producing a biomass solid fuel according to one aspect of the present invention, the particle size of the coal is preferably 1 mm or less.

In the method for producing a biomass solid fuel according to one aspect of the present invention, the ratio of the coal to the biomass in the biomass raw material (coal / biomass) is 0/100 or more and 75/25 or less in terms of mass ratio. preferable.

According to one aspect of the present invention, it is a method for adjusting the water content of a biomass solid fuel obtained by molding a biomass raw material containing biomass into a lump.
Provided is a method for adjusting the water content of a biomass solid fuel, which comprises a water content adjusting step of adjusting the water content of the biomass solid fuel to 5% by mass or more and 25% by mass or less by adding water to the biomass solid fuel.

In the method for adjusting the water content of a biomass solid fuel according to one aspect of the present invention, the biomass solid fuel is a biomass solid fuel obtained by the method for producing a biomass solid fuel according to any one of claims 1 to 9. Is preferable.

In the method for adjusting the water content of a biomass solid fuel according to one aspect of the present invention, when the means for detecting the water content of the biomass solid fuel detects that the water content is less than 5% by mass in the water content adjusting step. The step of adjusting the water content of the biomass solid fuel to 5% by mass or more and 25% by mass or less is preferable.

In the method for adjusting the water content of a biomass solid fuel according to one aspect of the present invention, in the water content adjusting step, the means for detecting the water content of the biomass solid fuel detects the water content, and the detected water content is adjusted to the water content. Based on this, the means for controlling the water content determines whether or not to add water to the biomass solid fuel, and based on the determined result, adjusts the water content to 5% by mass or more and 25% by mass or less. It is preferably a step.

According to one aspect of the present invention, the pellet-shaped or briquette-shaped biomass solid fuel containing biomass has a biomass content of 25% by mass or more and less than 95% by mass with respect to the biomass solid fuel, and contains water. Biomass solid fuels having a ratio of 5% by mass or more and 25% by mass or less are provided.

According to one aspect of the present invention, it is possible to provide a method for producing a biomass solid fuel that is less likely to cause a dust explosion, a method for adjusting the water content of the biomass solid fuel, and a biomass solid fuel.

The schematic diagram of the minimum ignition energy measuring apparatus used in the evaluation of an Example. The graph which shows the relationship between the dust concentration and the discharge energy in Example 1. FIG. The graph which shows the relationship between the dust concentration and the discharge energy in Example 2. The graph which shows the relationship between the dust concentration and the discharge energy in the comparative example 1. FIG. The graph which shows the relationship between the mixing ratio of the hydrated biomass raw material or the biomass powder in the biomass raw material, and the minimum ignition energy.

In the present specification, the lumpy substance means a solid substance obtained by molding a biomass raw material containing biomass. The lump is not particularly limited, and examples thereof include pellets and briquettes. The lump may be solidified to the extent that it can be used as fuel. Therefore, the size, shape, density, and the like of the lump are not particularly limited.

[First Embodiment]
[Manufacturing method of biomass solid fuel]
The method for producing a biomass solid fuel according to the first embodiment (hereinafter, also referred to as “the production method for the present embodiment”) will be described.
The production method of the present embodiment is a method for producing a biomass solid fuel obtained by molding a biomass raw material containing biomass into a lump, and specifically, the water content of the biomass solid fuel is 5% by mass or more. It has a step of adding water to at least one of the biomass raw material and the agglomerate so as to be 25% by mass or less.
The biomass solid fuel obtained by the production method of the present embodiment is obtained by molding a biomass raw material containing biomass into a lump, and by adding water to at least one of the biomass raw material and the lump, the water content is increased. It is adjusted to a specific range (5% by mass or more and 25% by mass or less).
The "lumps" referred to in the present embodiment are a lump after water is applied (a lump whose water content is adjusted to a specific range) and a lump before water is applied (moisture content is high). It is used in the concept that includes both (lumps that are not adjusted to a specific range).
Therefore, in the production method of the present embodiment, the mass whose water content is adjusted to a specific range is synonymous with the biomass solid fuel obtained by the production method of the present embodiment.

From the viewpoint of securing calorific value, it is desirable that the biomass solid fuel is as dry as possible. Therefore, when producing a biomass solid fuel, a step of drying the biomass raw material is usually provided in order to reduce the water content of the biomass raw material.
On the other hand, in the production method of the present embodiment, the water content of the obtained biomass solid fuel is adjusted to a specific range by adding water to at least one of the biomass raw material and the lumps obtained in the production process. That is, the production method of the present embodiment is the opposite of the conventional "reducing the water content of the biomass raw material", and the biomass solid fuel is intentionally contained with water.
Regarding the amount of water to be contained, by setting the water content of the biomass solid fuel to 5% by mass or more, the effect of increasing the minimum ignition energy and suppressing the ignition of the biomass is exhibited. Further, by setting the water content to 25% by mass or less, the calorific value as fuel is secured.
The water content of the semi-carbonized pellets whose water content has not been adjusted is usually less than 5% by mass. Further, when the semi-carbonized pellet is immersed in water, the water content of the semi-carbonized pellet is usually saturated at about 25% by mass.

Therefore, according to the production method of the present embodiment, it is possible to obtain a biomass solid fuel that is unlikely to cause a dust explosion even if dust is generated due to a mechanical impact or the like during transportation and storage of the biomass solid fuel. That is, the biomass solid fuel obtained by the production method of the present embodiment is a fuel with enhanced safety.
Hereinafter, the effect exerted by adjusting the water content of the biomass solid fuel to 5% by mass or more and 25% by mass or less (that is, the effect of making dust explosion less likely to occur) may be referred to as a "hydration effect".

-Transportation of biomass solid fuel "Transportation" during transportation of biomass solid fuel includes, for example, transportation from a predetermined location to the loading port, transportation from the loading port to the landing port, and power generation from the landing port to various places. Examples include transportation to the premises of a place, a steel mill, a factory, etc., and transportation from the premises to a fireplace. Examples of the means of transportation include elevators, cars, ships, conveyors, unloaders (coal lifters), belt feeders, and the like.

-During storage of biomass solid fuel "Storage" during storage of biomass solid fuel includes, for example, outdoor places, indoor covered places (dome type, warehouse type, etc.), shipyards, silos, and containers (for example, bins). ), Etc.

Further, in power plants, as described above, there is a demand to further increase the amount of biomass solid fuel used. According to the production method of the present embodiment, it is possible to produce a biomass solid fuel with improved safety, so that it is possible to meet the demand for an increase in the amount of the biomass solid fuel used.

The water content of the biomass solid fuel obtained by the production method of the present embodiment is 5% by mass or more and 25% by mass or less, but it is preferable from the viewpoint of further suppressing ignition of the biomass and further securing the calorific value. It is 5% by mass or more and 20% by mass or less, more preferably 5% by mass or more and 10% by mass or less.

The water content of the biomass solid fuel (5% by mass or more and 25% by mass or less), that is, the total water content (mass%) contained in the biomass solid fuel, imparts water to at least one of the biomass raw material and the lump in the manufacturing process. It is adjusted by.
The water content of the biomass solid fuel can be confirmed by the following method from the biomass solid fuel obtained by the production method of the present embodiment.
Collect 1 g of sample from biomass solid fuel. The collected sample is heated and dried at 107 ° C. ± 2 ° C. for 1 hour. The ratio of weight loss due to heat drying to the mass of the sample before heat drying is calculated as a percentage (%) (JIS M8820 (2000)). The above operation is performed three times to obtain the percentages, and the average value is taken as the water content of the biomass solid fuel.

The minimum ignition energy of the biomass raw material used in the production method of the present embodiment is preferably more than 10 mJ, more preferably more than 20 mJ, and further preferably more than 30 mJ from the viewpoint of obtaining a biomass solid fuel that is less likely to cause a dust explosion.
The minimum ignition energy of the biomass raw material can be measured by the method described in Examples described later.

The minimum ignition energy of the biomass solid fuel obtained by the production method of the present embodiment is preferably more than 10 mJ, more preferably more than 20 mJ, and further preferably more than 30 mJ from the viewpoint of making it difficult for dust explosion to occur.
The minimum ignition energy of the biomass solid fuel can be measured by taking a sample from the biomass solid fuel and using the sample in the same manner as the minimum ignition energy of the biomass raw material.

Hereinafter, the configuration of the manufacturing method of the present embodiment will be described.

<Process of adding water>
The step of adding water is a step of adding water to at least one of the biomass raw material and the agglomerate. The step of imparting water is not particularly limited, but a step of immersing in water, a step of spraying water, or a step of storing in a humidified space is preferable.
That is, the step of adding water to the biomass raw material is preferably a step of immersing the biomass raw material in water, a step of spraying water on the biomass raw material, or a step of storing the biomass raw material in a humidified space. The step of imparting water to the lumps is preferably a step of immersing the lumps in water, a step of spraying the lumps with water, or a step of storing the lumps in a humidified space.

The water content is not particularly limited, and for example, tap water, well water, natural water, industrial water, lake water, river water, spring water, distilled water, and the like can be used. In addition, moist air may be used as the moisture.
Examples of the state of water include water (liquid), water droplets, mist, water vapor, and the like. The temperature of the water is not limited.

In the step of immersing in water, it is preferable to appropriately set the type of water used, the amount of water, the temperature of water, the immersion time in water, and the like so as to be able to adjust the water content of the desired biomass solid fuel. The step of immersing in water can be performed using, for example, a water tank.
In the process of spraying water, the type of water used, the amount of water, the temperature of water, the state of water, the spraying time of water, etc. can be appropriately set so that the water content of the desired biomass solid fuel can be adjusted. preferable. The means for spraying the water is not particularly limited, and examples thereof include a spray, a shower, a sprinkler, and a hose. In addition, precipitation may be used as a means for spraying water.
In the process of storing in a humidified space, the state of the space used (for example, humidity, temperature, moisture state, size, etc.) and the time of storage in the humidified space are set to the desired water content of the biomass solid fuel. It is preferable to set it appropriately so that it can be adjusted.
The means for humidifying the space is not particularly limited, and examples thereof include steam and a known humidifying device. In addition, a humid natural environment may be used as a means for humidifying the space.

(Biomass raw material)
-Biomass Biomass raw materials include biomass.
The biomass is not particularly limited, and examples thereof include woody biomass, vegetation-based biomass, crop residue-based biomass, palm coconut biomass, cellulose products, and pulp products.
In the present specification, the crop residue biomass means something other than the edible portion.
In the present specification, the palm coconut biomass means agricultural waste of palm coconut which can be a biomass fuel. Specific examples of the palm coconut biomass include palm coconut shells (PKS: Palm Kernel Shell), palm coconut coconut bunches (EFB: Empty Fruit Bunch), and the like.
The biomass is preferably at least one selected from the group consisting of woody biomass, vegetation-based biomass, crop residue-based biomass, and palm palm biomass.

Examples of woody biomass include conifers (eg, sugi, pine, eucalyptus, cypress, fir, etc.) and broad-leaved trees (eg, white hippo, beech, zelkova, katsura, drill, rubber tree, kusunoki, etc.). The woody biomass may be construction waste (for example, cut offcuts, chips generated at a processing plant, sawdust, etc.), forest residue, thinned wood, bamboo, and the like.
Examples of vegetation-based biomass include grass, naturally grown plants, and artificially planted plants. The vegetation-based biomass may be hemp, cotton, rice straw, rice husks, straw, sasa, pampas grass and the like.

Examples of crop residue-based biomass include leaves, fruit bunches, stems, roots, and other non-edible parts of crops. Examples of the crop include wheat, corn, potato, sugar cane (including bagasse), sugar cane, starch, banana, castor oil and the like.

Examples of palm coconut biomass include palm oil pomace (PKS), fruit bunch (EFB), and fruit bark.
The biomass described above may be used alone or in combination of two or more.

The biomass is a powder, and the major axis diameter of the powder is preferably 5 mm or less, more preferably 1 mm or less, from the viewpoint of ease of molding into a lump. The lower limit of the major axis diameter of the powder is over 0.
The major axis diameter of the powder is the maximum diameter of the powder, and specifically, it means the maximum length of a straight line when any two points on the outer contour line of the powder are connected by a straight line.
The major axis diameter of the powder can be measured by the following method. 1 g of a sample is taken from biomass powder or biomass solid fuel, and the sample is observed with a scanning electron microscope (SEM). Measure the major axis diameter of the biomass powder in the observed field of view.

The content of biomass in the biomass raw material is preferably 25% by mass or more and 100% by mass or less, more preferably 100% by mass or less, based on the viewpoint of more exhibiting the watering effect and the demand for increasing the amount of biomass fuel used. It is 50% by mass or more and 100% by mass or less.

Biomass can be crushed into powder by using a known crusher.
For example, when wood is used as the woody biomass, a large piece of wood may be roughly crushed into chips of about several centimeters and then crushed into powder (preferably powder having a major axis diameter of 1 mm or less). When chips and small biomass are used, it is preferable to pulverize them into powder (preferably powder having a major axis diameter of 1 mm or less) using a known pulverizer.

The method for forming the lump is not particularly limited, but the lump is preferably compression-molded from the viewpoint of handling such as transportability and storability.
The shape and size of the lump are not particularly limited.
The mass is preferably pellets or briquettes. The pellets are usually cylindrical and have a diameter of 5 mm or more and 10 mm or less and a length of 5 mm or more and 50 mm or less. Briquettes usually have a larger diameter or length than pellets.
Pellets can be produced, for example, by extruding a biomass raw material or a biomass raw material having a adjusted water content from a metal hole (for example, a diameter of 5 mm or more and 10 mm or less and a length of 5 mm or more and 50 mm or less). Further, the pellets can be produced by using a pelletizer such as a ring die method or a flat die method.
The briquette can be produced, for example, by molding it into a charcoal-like or cylindrical shape using a briquette machine.

The biomass raw material or lump used in the production method of the present embodiment may be semi-carbonized. That is, in the production method of the present embodiment, in the step of adding water, the biomass raw material may be semi-carbonized and water may be added to the semi-carbonized biomass raw material, or the mass may be semi-carbonized and semi-carbonized. Moisture may be added to the biomass.
The method of semi-carbonizing is not particularly limited, and examples thereof include a method of heating a biomass raw material or a mass for a certain period of time in a container in which air is blocked to increase the carbonization degree by using a rotary kiln or the like.

Further, when the biomass raw material or the lump is not semi-carbonized, the step of adding water may be to add water to the biomass raw material before molding into the lump, or to add water to the lump. You may. The non-semi-carbonized lump is usually called white pellet.

-Coal The biomass raw material may include coal. Examples of coal include bituminous coal, sub-bituminous coal, and lignite.-Bituminous coal ... Coal with a total calorific value of 8,100 kcal / kg or more and less than 8,400 kcal / kg. Coal / lignite with a total calorific value of 7,300 kcal / kg or more and less than 8,100 kcal / kg according to the ash standard ... A total calorific value of 5,800 kcal / kg or more and less than 7,300 kcal / kg according to the anhydrous ash-free standard. coal

The coal is preferably crushed coal.
The particle size of coal is preferably 1 mm or less, more preferably 110 μm or less, from the viewpoint of ease of molding into a lump. The lower limit of the grain size of coal is over 0.
The particle size of coal can be adjusted, for example, using a sieve.

When the biomass raw material contains coal, the ratio of coal to biomass (coal / biomass) in the biomass raw material is preferable in terms of mass ratio from the viewpoint of more exhibiting the watering effect and the demand for increasing the amount of biomass fuel used. Is more than 0/100 and 75/25 or less, more preferably more than 0/100 and 50/50 or less.
When the ratio of coal to the biomass (coal / biomass) is more than 0/100 and 75/25, the watering effect is more likely to be exhibited.

The content of biomass in the biomass solid fuel obtained by the production method of the present embodiment is preferably 25 with respect to the biomass solid fuel from the viewpoint of more exhibiting the water-hydrating effect and the demand for increasing the amount of the biomass fuel used. It is mass% or more and 95% by mass or less, more preferably 50% by mass or more and 95% by mass or less.

The biomass solid fuel obtained by the production method of the present embodiment may contain other components other than biomass and coal as long as the effects of the present embodiment are not impaired.
The other components are not particularly limited, and examples thereof include binders and various additives.

[Usage of biomass solid fuel]
The biomass solid fuel obtained by the production method of the present embodiment can be widely used in power plants, steelworks, factories and the like. The biomass solid fuel of the present embodiment may be used by being burned alone, or may be mixed with other fuels such as coal and burned (co-firing).
For example, when the biomass solid fuel is used in a thermal power generation facility, the biomass solid fuel may be crushed by a crusher and introduced into a boiler, or may be introduced into a boiler as it is depending on the size.
It is also preferable to use the biomass solid fuel mixed with coal. In that case, the biomass solid fuel is crushed together with coal using an existing thermal power generation facility, for example, using a coal crusher, and these are boilers. May be introduced in.
Further, the biomass solid fuel may be crushed by a crusher different from the coal crusher (for example, a crusher for biomass solid fuel) and then mixed with separately crushed coal and introduced into the boiler.
The usage mode of the biomass solid fuel is not limited to the above.

[Second Embodiment]
[Moisture adjustment method for biomass solid fuel]
The method for adjusting the water content of the biomass solid fuel according to the second embodiment (hereinafter, also referred to as “the method for adjusting the water content of the present embodiment”) is a method for adjusting the water content of the biomass solid fuel obtained by molding a biomass raw material containing biomass into a lump. The method includes a water content adjusting step of adjusting the water content of the biomass solid fuel to 5% by mass or more and 25% by mass or less by adding water to the biomass solid fuel.

In the moisture adjustment method of the present embodiment, the biomass solid fuel to be subject to the moisture adjustment is, for example, 1) the biomass solid fuel produced by the production method of the first embodiment, which is exemplified in the first embodiment. Biomass solid fuel whose water content has decreased due to drying during "transportation of biomass solid fuel" or "storage of biomass solid fuel" (for example, biomass solid fuel whose water content has decreased to less than 5% by mass), 2) No. A biomass solid fuel produced by a method different from the production method of one embodiment, that is, a biomass solid fuel in which the water content is not adjusted can be mentioned.

In the water content adjusting method of the present embodiment, for example, the water content can be adjusted to 5% by mass or more and 25% by mass or less by carrying out the above water content adjusting step on the biomass solid fuel of 1) or 2) above. it can. As a result, it is possible to obtain a biomass solid fuel that is less likely to cause a dust explosion.

The water content adjusting step is preferably a step of adjusting the water content of the biomass solid fuel to preferably 5% by mass or more and 20% by mass or less, more preferably 5% by mass or more and 10% by mass or less.

The "adding water" in the water content adjusting method of the present embodiment is not particularly limited, but the step of immersing the biomass solid fuel in water, the step of spraying water on the biomass solid fuel, or the step described in the first embodiment, or The step of storing the biomass solid fuel in a humidified space is preferable.

In the water content adjusting method of the present embodiment, the biomass solid fuel to be the target of the water content adjustment is preferably the biomass solid fuel obtained by the production method of the first embodiment. That is, the biomass solid fuel of 1) above is preferable.

The water content of biomass solid fuel may change over time. Therefore, even when the biomass solid fuel having an adjusted water content is produced by the production method of the first embodiment, the water content may change over time.
For example, a biomass solid fuel having a water content of 5% by mass or more (preferably 10% by mass or more) is unlikely to cause a dust explosion, so that a biomass solid fuel having a reduced water content after drying (for example, having a water content of 5% by mass) By implementing the water content adjusting method of the present embodiment for a biomass solid fuel (less than%) or a biomass solid fuel having a tendency to decrease in water content, it is possible to obtain a biomass solid fuel that is less likely to cause dust explosion.
In addition, the biomass solid fuel having a water content of less than 5% by mass may be destroyed in the process of transportation, storage, and utilization and may be blown up as dust in the immovable part of the apparatus. Dust that has accumulated on the immovable parts of the device and dried can cause a dust explosion.
Therefore, the moisture adjusting method of the present embodiment is also effective in that it is possible to suppress the accumulation of dust on the immovable portion of the device, which may cause a dust explosion.

In the water content adjusting method of the present embodiment, in the water content adjusting step, the means for detecting the water content of the biomass solid fuel (hereinafter, also referred to as "water content detecting means") detects that the water content is less than 5% by mass. When this is done, it is preferable that the step is to adjust the water content of the biomass solid fuel to 5% by mass or more and 25% by mass or less.
The water content detecting means is not particularly limited, and for example, an optical detector or an electrical detector can be used. Examples of the optical detector include an infrared moisture meter and the like. Examples of the electric detector include a capacitance type moisture meter and the like.

In the water content adjusting method of the present embodiment, in the water content adjusting step, the means for detecting the water content of the biomass solid fuel detects the water content and controls the water content based on the detected water content ( Hereinafter, also referred to as "moisture content control means") determines whether or not to add water to the biomass solid fuel, and adjusts the moisture content to 5% by mass or more and 25% by mass or less based on the determined result. It is preferable that the step is to perform.
The water content control means is not particularly limited, but for example, a known control device can be used.
That is, in the water content adjusting method of the present embodiment, when the water content (moisture content) of the biomass solid fuel is detected to be less than 5% by mass by the water content detecting means, the water content is sprayed by the water content controlling means. It is preferable to operate the apparatus or the equipment for spraying water to add water (for example, water) to the biomass solid fuel so that the water content of the biomass solid fuel is 5% by mass or more and 25% by mass or less.
In other words, in the water content adjusting method of the present embodiment, when the water content (moisture content) of the biomass solid fuel is detected to be 5% by mass or more by the water content detecting means, the water content is sprayed by the water content controlling means. It is preferable not to operate the equipment or the equipment for spraying water.
As a result, the water content of the biomass solid fuel can be continuously monitored, so that the biomass solid fuel can be handled more safely. As a result, the use of biomass solid fuel can be expanded, and the demand for increasing the amount of biomass solid fuel used can be met.
It is preferable that the device for spraying water or the equipment for spraying water be installed in a part where dust easily collects, specifically, in the vicinity of an immovable part of the device or in a part where it is difficult to clean.

In the present embodiment, as the biomass contained in the biomass raw material, the same biomass as that described in the first embodiment can be used. As the coal contained in the biomass raw material, the same coal as that described in the first embodiment can be used.
In the present embodiment, the “biomass content in the biomass raw material” and the “ratio of coal to biomass in the biomass raw material (coal / biomass)” are the same as in the first embodiment.

[Third Embodiment]
[Biomass solid fuel]
The biomass solid fuel according to the third embodiment is a pellet-shaped or briquette-shaped biomass solid fuel containing biomass.
The content of the biomass is 25% by mass or more and less than 95% by mass with respect to the biomass solid fuel, and the water content of the biomass solid fuel is 5% by mass or more and 25% by mass or less.
When the water content of the biomass solid fuel is 5% by mass or more, the effect of increasing the minimum ignition energy and suppressing the ignition of the biomass is exhibited.
When the water content of the biomass solid fuel is 25% by mass or less, the calorific value as the fuel is secured.
When the content of biomass is 25% by mass or more and less than 95% by mass with respect to the solid biomass fuel, the effect of suppressing ignition of the biomass due to the inclusion of water in the solid biomass fuel is likely to be exhibited.
Therefore, according to the biomass solid fuel of the present embodiment, even if dust is generated due to a mechanical impact or the like during transportation and storage, the dust explosion is less likely to occur.

The water content of the biomass solid fuel of the present embodiment is preferably 5% by mass or more and 20% by mass or less, more preferably 5% by mass or more and 10 from the viewpoint of further suppressing ignition of the biomass and further securing the calorific value. It is less than mass%.
Further, the water content of the biomass solid fuel of the present embodiment is preferably 8.0% by mass or more and 25% by mass or less, and 9.1% by mass or more and 25% by mass or less, from the viewpoint of further suppressing ignition of the biomass. It is also preferable that it is as follows.

The ratio of coal to biomass (coal / biomass) in the biomass solid fuel of the present embodiment is preferably more than 0/100 and 75/25 or less in terms of mass ratio.

The biomass solid fuel of the present embodiment is preferably a biomass solid fuel produced by the production method of the first embodiment. That is, the biomass solid fuel of the present embodiment is obtained by pelletizing or pelletizing a biomass raw material containing powdery (powder) biomass and crushed coal among the biomass solid fuel produced by the production method of the first embodiment. It is preferably obtained by compression molding into a briquette shape.
In the present embodiment, as the biomass contained in the biomass solid fuel, the same biomass as that described in the first embodiment can be used. As the coal contained in the biomass solid fuel, the same coal as that described in the first embodiment can be used.

The biomass solid fuel of the present embodiment is preferably a biomass solid fuel whose water content has been adjusted by the water content adjusting method of the second embodiment.

[Other Embodiments]
The present invention is not limited to the above-described embodiment, and changes, improvements, etc. within the scope of achieving the object of the present invention are included in the present invention.

Hereinafter, examples according to the present invention will be described. The present invention is not limited to these examples.

Table 1 shows the properties of coal and biomass used in Examples and Comparative Examples.

-Explanation of Table 1 The industrial analysis values are values measured in accordance with JIS M8812 (2004).
Of the elemental analysis values, carbon, hydrogen, nitrogen and sulfur are values measured in accordance with JIS M8819 (1997), and oxygen is a value calculated from other analysis values in accordance with JIS M8813 (2004). is there.
The high calorific value is a value measured in accordance with JIS M8814 (2003).
The fuel ratio is "fixed carbon / volatile matter".
"Ar" is an abbreviation for As Received Base, which represents an arrival base and indicates an untouched state. The same applies to Table 2.
"Ad" is an abbreviation for Air Dry Basis, which represents an air-drying base and represents a state of being dried in the air. The same applies to Table 2.
"Daf" is an abbreviation for Dry Ash Free, and represents an anhydrous ash-free base, and represents a virtual state assuming that coal does not contain water and ash. Obtained by conversion from the analyzed value.
“<0.01” represents “less than 0.01”.

The ignition test and the explosion test performed in this example were performed on the assumption that the fine powder generated from the biomass solid fuel flies in the air and causes a dust explosion. Therefore, powder was used in both the ignition test and the explosion test. Biomass powder and pulverized coal as powder were prepared as follows.

[Example 1]
<Making biomass powder>
Semi-carbonized pelletized biomass (woody biomass (rubber tree) manufactured by Siambiomas) was pulverized by a pulverizer and sieved through a sieve having a mesh size of 105 μm (140 mesh) to prepare biomass powder having a particle size of 105 μm or less.

<Making pulverized coal>
Coal (brown coal from Indonesia) was crushed by a crusher and sieved to 105 μm (140 mesh) like biomass to prepare pulverized coal having a particle size of 105 μm or less.

<Preparation of biomass raw materials>
50 parts by mass of biomass powder and 50 parts by mass of pulverized coal were mixed to obtain a mixed powder of biomass powder and pulverized coal. This was used as a biomass raw material.

<Water added to biomass raw materials>
Using a closed container, add 5 parts by mass of water to 100 parts by mass of the biomass raw material, put it in the container, cover it tightly so that it will not spill even if shaken, and use a shaker for 2 hours. The mixture was mixed to obtain a hydrous biomass raw material having a water content of 12.2% by mass (hereinafter, also referred to as “hydrogen biomass raw material”).
The water content of the hydrated biomass raw material was calculated as follows in consideration of the total water content of the biomass (4.9 wt%) and the total water content of coal (10.8 wt%) shown in Table 1.
Moisture content [mass%] = (5 + 2.45 + 5.4) /105=12.2

[Example 2]
In the "watering to the biomass raw material" of Example 1, the water content was 16.2 mass by the same method as in Example 1 except that 10 parts by mass of water was sprayed on 100 parts by mass of the biomass raw material. % Of the hydrobiomass raw material of Example 2 was obtained.
The water content of the hydrated biomass raw material was calculated as follows in consideration of the total water content of the biomass (4.9 wt%) and the total water content of coal (10.8 wt%) shown in Table 1.
Moisture content [mass%] = (10 + 2.45 + 5.4) /110=16.2

[Comparative Example 1]
The biomass powder and pulverized coal used in Example 1 were mixed by mass in parts shown in Table 2, and the mixed powder was used as the biomass raw material of Comparative Example 1. In Comparative Example 1, "watering the biomass raw material" was not performed. Similarly, in Comparative Examples 2 and Reference Examples 1 to 3 described later, water was not added to the biomass raw material.
The water content of the biomass raw material of Comparative Example 1 was calculated from the total water content of the biomass (4.9 wt%) and the total water content of coal (10.8 wt%) shown in Table 1.

[Comparative Example 2]
The biomass powder used in Example 1 was used as the biomass raw material of Comparative Example 2.
The water content of the biomass raw material of Comparative Example 2 corresponds to the total water content (4.9 wt%) of the biomass shown in Table 1.

[Reference Example 1]
The pulverized coal used in Example 1 was used as the coal raw material of Reference Example 1.
The water content of the coal raw material of Reference Example 1 corresponds to the total water content (10.8 wt%) of the coal shown in Table 1.

[Reference Examples 2-3]
The biomass powder and pulverized coal used in Example 1 were mixed by mass in parts shown in Table 2 and used as the biomass raw materials of Reference Examples 2 and 3, respectively.
The water content of the biomass raw materials of Reference Examples 2 and 3 was calculated from the total water content of the biomass (4.9 wt%) and the total water content of coal (10.8 wt%) shown in Table 1.

[Evaluation]
The following evaluations were made using the hydrated biomass raw materials obtained in Examples 1 and 2, the biomass raw materials obtained in Comparative Examples 1 and 2 and Reference Examples 2 and 3, and the coal raw materials obtained in Reference Example 1 as samples. Was done.

[Minimum ignition energy]
The minimum ignition energy was measured using the minimum ignition energy measuring device (MIKE3 type manufactured by Adolf Kuhner AG) shown in FIG.
The minimum ignition energy measuring device (made by Adolf Kuhner AG, MIKE3 type) complies with the international standard "ISO / IEC 80079-20-2 Edition 1.0 2016-02: 8.3 Method for determining minimum ignition energy of dust / airsample". ..

First, the minimum ignition energy measuring device 100 will be described.
The minimum ignition energy measuring device 100 includes a cylindrical combustion container 10 (inner diameter 7 cm, internal volume 1.2 L), a first support 30 for supporting the combustion container 10, and a second support 32. I have. A filter paper 28 is arranged on the upper part of the combustion container 10.
Inside the combustion container 10, a pair of ignition electrodes 12 arranged so as to face each other are provided. The pair of ignition electrodes 12 extend from the inside to the outside of the combustion container 10 and are covered with electrical insulating materials 26a and 26b outside the combustion container 10. The pair of ignition electrodes 12 are connected to a capacitance discharge type ignition device (not shown). When a voltage is applied from the ignition device, a discharge is generated between the ignition electrodes 12, and the generated discharge energy forms a discharge spark between the ignition electrodes 12.
The combustion container 10 has a dispersion plate 14 on the bottom side, and a sample (hydromass raw material, biomass raw material, or coal raw material) is introduced into the dispersion plate 14. Further, the dispersion plate 14 is provided with a reflector 16.
The dispersion pan 14 of the combustion vessel 10 is connected to a pipe 18 for blowing compressed air into the combustion vessel 10. The pipe 18 passes through the inside of the first support base 30 and the second support base 32, and is connected to the pipe 20 having an outer diameter smaller than that of the pipe 18. Compressed air supplied from a compressor (not shown) is stored in the compressed air reservoir 24. Compressed air is introduced into the inside from the bottom side of the combustion container 10. The supply and stop of the compressed air to the combustion container 10 is controlled by the solenoid valve 22 provided in the pipe 20.
The height H (FIG. 1) from the upper part of the first support base 30 to the ignition electrode 12 is 7.6 cm.

The minimum ignition energy was determined by conducting an ignition test. The following ignition test was carried out by connecting an inductance of 1 mH in the discharge circuit.

<Ignition test of Example 1>
First, the dust concentration of the combustion chamber ^{10, 750g / m 3, 1000g} / m 3, 1250g / m 3, 1500g / m 3, so that the 1750 g / ^{m 3} and 2000 g / ^{m 3,} samples were prepared. The sample amounts for each dust concentration are 0.9 g, 1.2 g, 1.5 g, 1.8 g, 2.1 g and 2.4 g, respectively.
Next, 0.9 g of a sample (a sample prepared so that the dust concentration was 750 g / m ³ ) was placed on a dispersion dish 14 of the combustion vessel 10. Compressed air was supplied from the compressed air reservoir 24 to the combustion vessel 10, and the sample was blown up into the combustion vessel 10 and dispersed. With a capacitance discharge type ignition device, the discharge energy is changed to 7 stages of 1 mJ, 3 mJ, 10 mJ, 30 mJ, 100 mJ, 300 mJ and 1 J to determine the presence or absence of ignition by each discharge energy, and if necessary, the ignition delay time is changed. I asked for the presence or absence of ignition.
In the ignition test, a test with a sample amount of 0.9 g and each discharge energy is performed 10 times to check for ignition, and if the sample ignites even once out of 10 times, the ignition property is "Yes" under that condition. When the sample did not ignite even once, it was determined that the ignitability was "none" under that condition.

Next, the sample amount of 0.9 g is changed in order to the sample amounts of 1.2 g, 1.5 g, 1.8 g, 2.1 g and 2.4 g, and each sample is ignited in the same manner as described above. The test was conducted.
The results are shown in Table 2.

-Explanation of Table 2 The test under the conditions not shown in Table 2 (for example, sample amount 0.9 g, discharge energy 1 mJ) is not performed because the result is predicted. The same applies to Tables 3 to 4 described later.

-Minimum ignition energy of Example 1 Fig. 2 was created from the results in Table 2. FIG. 2 is a graph showing the relationship between the dust concentration and the discharge energy.
From FIG. 2, the minimum ignition energy (E _min ) of the hydrated biomass raw material of Example 1 is 10 mJ <E _min <30 mJ, and the statistical minimum ignition energy (Es) is 19 mJ.
The statistical minimum ignition energy (Es) was calculated from the probability of ignition by the following mathematical formula (1) in accordance with EN13821: 2002 and SAP12-10-2010 (standard of Japan Powder Industry Technology Association). In this test, this statistical minimum ignition energy (Es) was used as the minimum ignition energy (mJ).

Es: Statistical minimum ignition energy E ₁ : Minimum ignited discharge energy E ₂ : Maximum non-ignited discharge energy I [E ₂ ]: Number of ignited dust concentrations in E ₂ (NI + I) [E ₂ ]: The total number of dust concentrations tested Es, E ₁ and E ₂ are all in units of (mJ).

<Ignition test of Example 2>
Dust concentration of the combustion chamber ^{10, 750g / m 3, 1000g /} m 3, 1500g / m 3, 2000g / m 3, so that 2250 g / ^{m 3} and 2500 g / ^{m 3,} samples were prepared. The sample amounts for each dust concentration are 0.9 g, 1.2 g, 1.8 g, 2.4 g, 2.7 g and 3.0 g, respectively.
Other than that, the ignition test was carried out in the same procedure as in Example 1. The results are shown in Table 3.

-Minimum ignition energy of Example 2 Fig. 3 was created from the results in Table 3. FIG. 3 is a graph showing the relationship between the dust concentration and the discharge energy.
From FIG. 3, the minimum ignition energy (E _min ) of the hydrated biomass raw material of Example 2 is 30 mJ <E _min <100 mJ, and the statistical minimum ignition energy (Es) is 60 mJ. The statistical minimum ignition energy (Es) was determined by the same method as in Example 1.

<Ignition test of Comparative Example 1>
Dust concentration of the combustion chamber ^{10, 1000g / m 3, 1500g /} m 3, 1750g / m 3, 2000g / m 3, so that 2250 g / ^{m 3} and 2500 g / ^{m 3,} samples were prepared. The sample amounts for each dust concentration are 1.2 g, 1.8 g, 2.1 g, 2.4 g, 2.7 g and 3.0 g, respectively.
The ignition test was carried out in the same procedure as in Example 1. The results are shown in Table 4.

-Minimum ignition energy of Comparative Example 1 Fig. 4 was created from the results in Table 4. FIG. 4 is a graph showing the relationship between the dust concentration and the discharge energy.
From FIG. 4, the minimum ignition energy (E _min ) of the biomass raw material of Comparative Example 1 was 3 mJ <E _min <10 mJ, and the statistical minimum ignition energy (Es) was 6.0 mJ. The statistical minimum ignition energy (Es) was determined by the same method as in Example 1.

<Ignition test and minimum ignition energy of Comparative Examples 2 and Reference Examples 1 to 3>
Instead of the hydrated biomass raw material of Example 1, the biomass powder of Comparative Example 2, the coal powder of Reference Example 1, and the biomass raw materials of Reference Examples 2 and 3 were changed, respectively, and each example was subjected to the same procedure as in Example 1. An ignition test was performed to determine the statistical minimum ignition energy (Es).

<Relationship between the mixing ratio of biomass powder and the minimum ignition energy>
FIG. 5 shows the relationship between the mixing ratio of biomass powder in the biomass raw material and the minimum ignition energy.
Areas A, B, and C shown in FIG. 5 are "countermeasures for each minimum ignition energy of powder" described in the determination diagram of ignition risk due to electrostatic charge (dust explosion fire countermeasures, Japanese powder corporation). Based on "R. Siwek and C. Cesana: Ignition behavior of dusts: Meaning and interpretation, Process Safety Progress, 14, 2, pp.107-119 (1995)", edited by the Dust Explosion Committee of the Institute of Physical and Industrial Technology. It was defined as follows.
-Area A: An area that can be dealt with by avoiding electrostatic charge due to grounding measures such as containers.
-Area B: An area where explosion danger and explosion control are required, such as installation of a human body. Region B is a "region that requires attention".
-Region C: An area where measures for inactivating the entire container and control of the carry-in speed are required. Area C is an "extremely sensitive area".

[Lower explosion concentration]
As a blow-up test device defined in "Method for measuring the lower limit concentration of flammable dust explosion" of JIS Z8818 (2002), a test device having the same configuration as the minimum ignition energy measuring device 100 shown in FIG. 1 was used. The lower limit of explosion concentration was calculated.

The lower limit of explosion concentration was determined by conducting an explosion test. The measurement conditions are as follows.
-Measurement conditions-
-Temperature: 20.1 ° C to 20.3 ° C
・ Relative humidity: 13% to 14%
・ Blow-up pressure: 30 kPa or more and 50 kPa or less

<Explosion test of Example 1>
As a sample, the hydrobiomass raw material of Example 1 was used.
First, the dust concentration in the combustion vessel is 65 g / m ³ , 70 g / m ³ , 75 g / m ³ , 80 g / m ³ , 85 g / m ³ , 90 g / m ³ , 95 g / m ³ , 100 g / m ^3, and 110 g. / m so that the ^3, samples were prepared.

Next, a sample prepared so that the dust concentration was 65 g / m ³ (hereinafter, also referred to as “Sample A”) was placed on a dispersion dish of a combustion container.
Compressed air was supplied from the compressed air reservoir to the combustion vessel, and the sample was blown up into the combustion vessel to disperse it, and a dust cloud was generated. A neon transformer with a secondary output of 15 kV and a capacity of 20 mA was used as the ignition source.
When the sample was blown into the combustion vessel, a discharge spark was generated at the same time (discharge start time 0.1 seconds), and at this time, it was visually determined whether or not the dust cloud exploded. This operation was repeated by changing the air pressure and the like as necessary. The explosion test was repeated 5 times under the same conditions. The explosion test under the same conditions was stopped when the explosion was confirmed out of 5 times. The minimum dust concentration showing explosiveness, that is, the dust concentration at the time when the explosion was confirmed was defined as the "explosion lower limit concentration (apparent explosion lower limit concentration)".

Next, the dust concentration of sample A was adjusted to 70 g / m ³ , 75 g / m ³ , 80 g / m ³ , 85 g / m ³ , 90 g / m ³ , 95 g / m ³ , 100 g / m ³ and 110 g / m ³ . The samples were changed in order so that each sample was subjected to an explosion test in the same manner as described above. The results are shown in Table 5.

-Explanation of Table 5 (65) at a dust concentration of 65 g / m ³ means that the measurement was performed with reference to the presence or absence of an explosion of a dust cloud. The same applies to (60) in Table 6 described later.

-Explosion lower limit concentration of Example 1 From Table 5, the explosion lower limit concentration of the hydrated biomass raw material of Example 1 was 80 g / m ³ .

<Explosion test of Comparative Example 1>
As a sample, the mixed powder of Comparative Example 1 was used.
First, the dust concentration of the combustion vessel 10 is 60 g / m ³ , 65 g / m ³ , 70 g / m ³ , 75 g / m ³ , 80 g / m ³ , 85 g / m ³ , 90 g / m ³ , 95 g / m ³ , An explosion test was carried out in the same procedure as in Example 1 in which samples were prepared so as to be 100 g / m ³ and 110 g / m ³ , respectively. The results are shown in Table 6.

-Explosion lower limit concentration of Comparative Example 1 From Table 6, the explosion lower limit concentration of the mixed powder of Comparative Example 1 was 75 g / m ³ .

<Explosion lower limit concentration of Example 2, Comparative Example 2 and Reference Examples 1 to 3>
Instead of the hydrated biomass raw material of Example 1, the hydrated biomass raw material of Example 2, the biomass powder of Comparative Example 2, the coal powder of Reference Example 1, and the biomass raw material of Reference Examples 2 and 3 were changed, respectively, and Example 1 The explosion test of each example was carried out in the same procedure as in the above, and the lower limit explosion concentration was determined.
The results are shown in Table 7.

-Explanation of Table 7 "-" indicates that the measurement was not performed.

From Table 7 and FIG. 5, the hydrated biomass raw materials of Examples 1 and 2 produced by adding water so that the water content was 5% by mass or more and 25% by mass or less were compared with Comparative Examples 1 and 2 produced without adding water. The minimum ignition energy is higher than that of biomass raw materials.
In addition, the hydrous biomass raw material of Example 1 had a higher explosion lower limit concentration than the biomass raw materials of Comparative Examples 1 and 2.
In addition, the hydrated biomass raw materials of Examples 1 and 2 ensured a high calorific value on an arrival basis.
Further, according to the present embodiment, as shown in FIG. 5, by using the biomass raw material as the hydrous biomass raw material, the biomass raw material in the region C can be shifted toward the region A.
Therefore, when a biomass solid fuel is produced using the hydrated biomass raw material of this example, the water content of the obtained biomass solid fuel reflects the water content of the hydrated biomass raw material, so that the biomass solid fuel is less likely to cause dust explosion. Can be obtained.

The biomass solid fuel obtained by the production method of the present invention is less likely to cause a dust explosion, so that the biomass can be handled safely. As a result, the use of biomass can be expanded in power plants, steelworks, factories, and the like.

10 ... Combustion container, 12 ... Ignition electrode, 14 ... Dispersion plate, 16 ... Reflector, 18 ... Pipe, 20 ... Piping, 22 ... Solenoid valve, 24 ... Compressed air reservoir, 26a, 26b ... Electrical insulation, 28 ... Filter paper, 30 ... 1st support, 32 ... 2nd support, 100 ... Minimum ignition energy measuring device.

Claims (14)

A method for producing a biomass solid fuel obtained by molding a biomass raw material containing biomass into a lump.
A method for producing a biomass solid fuel, which comprises a step of adding water to at least one of the biomass raw material and the agglomerate so that the water content of the biomass solid fuel is 5% by mass or more and 25% by mass or less. In the method for producing a biomass solid fuel according to claim 1,
The step of imparting water is a step of immersing the biomass raw material in water, a step of spraying water on the biomass raw material, or a step of storing the biomass raw material in a humidified space, which is a method for producing a biomass solid fuel. In the method for producing a biomass solid fuel according to claim 1,
The step of imparting water is a step of immersing the lump in water, a step of spraying water on the lump, or a step of storing the lump in a humidified space, which is a method for producing a biomass solid fuel. In the method for producing a biomass solid fuel according to any one of claims 1 to 3.
The biomass is a method for producing a solid biomass fuel, which is at least one selected from the group consisting of woody biomass, vegetation-based biomass, crop residue-based biomass, and palm palm biomass. In the method for producing a biomass solid fuel according to any one of claims 1 to 4.
A method for producing a solid biomass fuel, wherein the biomass is a powder and the major axis diameter of the powder is 5 mm or less. In the method for producing a biomass solid fuel according to any one of claims 1 to 5.
A method for producing a biomass solid fuel, wherein the lump is a pellet or a briquette. The method for producing a biomass solid fuel according to any one of claims 1 to 6.
The biomass raw material is a method for producing a biomass solid fuel further containing coal. In the method for producing a biomass solid fuel according to claim 7,
A method for producing a biomass solid fuel, wherein the coal has a particle size of 1 mm or less. In the method for producing a biomass solid fuel according to claim 7 or 8.
A method for producing a solid biomass fuel, wherein the ratio of the coal to the biomass (coal / biomass) in the biomass raw material is 0/100 or more and 75/25 or less in terms of mass ratio. A method for adjusting the water content of a biomass solid fuel obtained by molding a biomass raw material containing biomass into a lump.
A method for adjusting the water content of a biomass solid fuel, which comprises a water content adjusting step of adjusting the water content of the biomass solid fuel to 5% by mass or more and 25% by mass or less by adding water to the biomass solid fuel. In the method for adjusting the water content of a biomass solid fuel according to claim 10.
The method for adjusting the water content of a biomass solid fuel, wherein the biomass solid fuel is a biomass solid fuel obtained by the method for producing a biomass solid fuel according to any one of claims 1 to 9. In the method for adjusting the water content of a biomass solid fuel according to claim 10 or 11.
In the water content adjusting step, when the means for detecting the water content of the biomass solid fuel detects that the water content is less than 5% by mass, the water content of the biomass solid fuel is increased by 5% by mass or more and 25% by mass. A method for adjusting the water content of biomass solid fuel, which is a step of adjusting below. In the method for adjusting the water content of a biomass solid fuel according to claim 10 or 11.
In the water content adjusting step, the means for detecting the water content of the biomass solid fuel detects the water content, and the means for controlling the water content based on the detected water content is the biomass solid fuel. A method for adjusting the water content of a biomass solid fuel, which is a step of determining whether or not to add water and adjusting the water content to 5% by mass or more and 25% by mass or less based on the determined result. Pellet-like or briquette-like biomass solid fuel containing biomass,
A biomass solid fuel having a biomass content of 25% by mass or more and less than 95% by mass and a water content of 5% by mass or more and 25% by mass or less with respect to the biomass solid fuel.