Method for producing biomass fuel and system for producing biomass fuel

Abstract

This method for producing a biomass fuel includes: a management step S130 for managing a carry-in date for a biomass to be carried into a stock yard; a dispensing step S140 for dispensing the biomass from the stock yard on the basis of the carry-in date; a squeezing step S160 for squeezing the biomass that has been dispensed by the dispensing step S140 to remove a squeeze liquid from the biomass; a first washing step S170 for washing the biomass that has been squeezed by the squeezing step 160 with water; and a first dehydrating step S180 for squeezing the biomass that has been washed by the first washing step S170 to dehydrate the biomass.

Description

Biomass fuel production method and biomass fuel production system

[0001] This disclosure relates to a method and system for producing biomass fuel. This application claims the benefit of priority from Japanese Patent Application No. 2023-143226, filed on September 4, 2023, the contents of which are incorporated herein by reference.

[0002] To reduce carbon dioxide emissions, which contribute to global warming, technologies that use biomass such as agricultural waste as fuel are attracting attention. Most biomass tends to contain more ash, such as potassium and sodium, than coal.

[0003] Therefore, if biomass is fed directly into a boiler without processing, ash will adhere to the inner walls of the furnace and the outer surfaces of the heat exchanger, such as heat transfer tubes. This will hinder the flow of gas within the boiler and reduce the heat exchange efficiency of the heat exchanger. Furthermore, if the boiler is a circulating fluidized bed boiler, in addition to the ash adhering to the inner walls of the furnace and the outer surfaces of the heat exchanger, the ash will cause the bed material, such as sand, that forms the fluidized bed to agglomerate. This will cause poor fluidity of the bed material, preventing the formation of a fluidized bed, and may result in the boiler and equipment connected to the boiler being clogged by the agglomerated bed material.

[0004] Therefore, as a technique for removing ash from biomass, for example, Patent Document 1 discloses a technique in which oil palm fronds (OPF) are heated with saturated steam at 100°C to 200°C for 15 to 60 minutes to soften the OPF, and then washed with water.

[0005] Patent No. 6289789

[0006] However, in the conventional technology of heating biomass before washing with water as in Patent Document 1, energy is consumed for heating, which results in unnecessary energy consumption when producing biomass fuel that generates energy, resulting in a problem of low energy efficiency.

[0007] In view of these problems, the present disclosure aims to provide a biomass fuel production method and a biomass fuel production system that can improve energy efficiency.

[0008] In order to solve the above problems, a method for producing biomass fuel according to one embodiment of the present disclosure includes a management process for managing the delivery date of biomass delivered to a stockyard; a discharge process for discharging the biomass from the stockyard based on the delivery date; a pressing process for removing juice from the biomass by compressing the biomass discharged in the discharge process; a first washing process for washing the biomass compressed in the pressing process with water; and a first dehydration process for dehydrating the biomass by compressing the biomass washed in the first washing process.

[0009] Furthermore, the method for producing biomass fuel does not necessarily have to include a heating step of heating the biomass before the pressing step.

[0010] In addition, in the unloading step, biomass that has been unloaded within four days from the day of delivery may be unloaded from the stockyard.

[0011] In addition, in the pressing step, the moisture content of the biomass to be pressed may be 50% by mass or more and 80% by mass or less.

[0012] Furthermore, in the compression step, the compression force when compressing the biomass may be 30 MPa or more and 60 MPa or less.

[0013] Furthermore, the biomass is EFB produced when oil palm is extracted, and the date of delivery may be the date on which the EFB is discharged from the oil palm oil extraction factory.

[0014] Alternatively, the biomass may be OPT left at a palm plantation, and the delivery date may be the date on which the OPT was removed from the palm plantation.

[0015] The method for producing biomass fuel may further include a second washing step in which the biomass dehydrated in the first dehydration step is washed with water, and a second dehydration step in which the biomass washed in the second washing step is compressed to dehydrate the biomass.

[0016] In order to solve the above problems, a biomass fuel production system according to one embodiment of the present disclosure includes a management device that manages the delivery date of biomass delivered to a stockyard, a discharge device that discharges biomass from the stockyard based on the delivery date, a compression device that removes juice from the biomass by compressing the biomass discharged by the discharge device, a washing device that washes the biomass compressed by the compression device with water, and a dehydration device that dehydrates the biomass by compressing the biomass washed by the washing device.

[0017] According to the present disclosure, it is possible to improve energy efficiency.

[0018] Fig. 1 is a diagram illustrating a biomass fuel production system according to an embodiment. Fig. 2 is a flowchart showing the process flow of a biomass fuel production method according to an embodiment. Fig. 3 is a graph showing the relationship between the amount of squeezed juice and the amount of residual potassium. Fig. 4 is a graph showing the amounts of sparingly soluble potassium and readily soluble potassium when no squeezing is performed and when a compressive force of 20 MPa and a compressive force of 40 MPa are used. Fig. 5 is a graph showing the elution rates of sparingly soluble potassium and readily soluble potassium when no squeezing is performed and when a compressive force of 20 MPa and a compressive force of 40 MPa are used.

[0019] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples for ease of understanding and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation. Elements not directly related to the present disclosure are not shown.

[0020] [Biomass fuel production system 100] Figure 1 is a diagram illustrating a biomass fuel production system 100 according to this embodiment. In Figure 1, solid arrows indicate the flow of biomass. Also, in Figure 1, dashed arrows indicate the flow of gas.

[0021] The biomass fuel production system 100 is installed, for example, near the oil palm oil mill 10, such as on the premises of the oil palm oil mill 10. In this embodiment, the biomass fuel production system 100 produces biomass fuel by removing ash from biomass, for example, empty fruit bunches (EFBs) that are generated when oil palms are pressed.

[0022] As shown in FIG. 1, the biomass fuel production system 100 includes, for example, a management device 110, a discharge device 120, a primary cutting device 130, a pressing device 140, a first cleaning device 150, a first dehydration device 160, a second cleaning device 170, a second dehydration device 180, a drying device 190, a secondary cutting device 200, and a molding device 210.

[0023] The management device 110 is composed of a semiconductor integrated circuit including a CPU (central processing unit). The management device 110 reads programs and parameters for operating the CPU from ROM. The management device 110 manages and controls the entire biomass fuel production system 100 in cooperation with RAM as a work area and other electronic circuits.

[0024] In this embodiment, the management device 110 manages the delivery date of biomass delivered to the stockyard 20. The management device 110 may manage the delivery date of biomass delivered to the stockyard 20 based on, for example, an operation input by an operator of the biomass fuel production system 100.

[0025] The stockyard 20 has, for example, a plurality of compartments 22. Biomass discharged from the oil expression factory 10 is piled up in each compartment 22 for each delivery date. For example, in the stockyard 20, a delivery date is assigned to each compartment 22, and biomass successively delivered to the stockyard 20 is stored separately in the compartments 22 for each delivery date. Therefore, in the stockyard 20, biomass piles 30 for each delivery date are formed in each compartment 22.

[0026] The discharge device 120 discharges the biomass from the stockyard 20 based on the carry-in date. The discharge device 120 includes, for example, either one or both of a power shovel and a conveyor.

[0027] The primary cutting device 130 cuts the biomass discharged by the discharge device 120. The primary cutting device 130 cuts the biomass into pieces of, for example, about 5 cm (primary cutting).

[0028] The compression device 140 removes juice from the biomass by compressing the biomass that has been discharged by the discharge device 120 and primarily cut by the primary cutting device 130. The compression device 140 includes, for example, a hydraulic press.

[0029] The first washing device 150 (washing device) washes with water the biomass compressed by the compressing device 140. In this embodiment, the first washing device 150 includes, for example, a storage tank 152 and a bubbling section 154.

[0030] Water at room temperature is stored in the storage tank 152. Room temperature is, for example, 20° C. or higher and 35° C. or lower. The biomass compressed by the compression device 140 is introduced into the storage tank 152. The storage tank 152 stores a solid-liquid mixture of biomass and water.

[0031] The bubbling unit 154 bubbles (supplies) a gas into the solid-liquid mixture contained in the storage tank 152. In this embodiment, the bubbling unit 154 bubbles the gas used to dry the biomass in, for example, a drying device 190 described below.

[0032] The first dewatering device 160 (dewatering device) dewaters the biomass by squeezing the biomass washed by the first washing device 150. The first dewatering device 160 includes, for example, either or both of a filter press and a screw press.

[0033] The second washing device 170 washes with water the biomass dewatered by the first dewatering device 160. In this embodiment, the second washing device 170 includes, for example, a storage tank 172 and a bubbling section 174.

[0034] Water at room temperature is stored in the storage tank 172. The biomass that has been dehydrated by the first dehydration device 160 is introduced into the storage tank 172. The storage tank 172 stores a solid-liquid mixture of biomass and water.

[0035] The bubbling unit 174 bubbles a gas into the solid-liquid mixture contained in the storage tank 172. In this embodiment, the bubbling unit 174 bubbles the gas used to dry the biomass in the drying device 190, for example.

[0036] The second dewatering device 180 dewaters the biomass by squeezing the biomass washed by the second washing device 170. The second dewatering device 180 includes, for example, either or both of a filter press and a screw press.

[0037] The drying device 190 dries the biomass dehydrated by the second dehydration device 180. In this embodiment, the drying device 190 dries the biomass using, for example, high-temperature air or high-temperature gas such as combustion exhaust gas. The combustion exhaust gas is gas generated when fuel is burned in a combustion device (not shown). The drying device 190 dries the primarily chopped biomass until the moisture content is about 10% by mass, for example.

[0038] The secondary cutting device 200 cuts the biomass dried by the drying device 190. The secondary cutting device 200 cuts the biomass into pieces of, for example, about 1 cm (secondary cutting).

[0039] The molding device 210 generates pellets by molding the biomass that has been secondarily cut by the secondary cutting device 200. The pellets have, for example, a cylindrical shape. In this way, biomass fuel (pellets) is produced.

[0040] [Biomass Fuel Production Method] Next, a method for producing biomass fuel will be described. FIG. 2 is a flowchart showing the process flow of the biomass fuel production method according to this embodiment. As shown in FIG. 2, the biomass fuel production method according to this embodiment includes, for example, a discharge step S110, a carry-in step S120, a management step S130, a discharge step S140, a primary cutting step S150, a pressing step S160, a first cleaning step S170, a first dehydration step S180, a second cleaning step S190, a second dehydration step S200, a drying step S210, a secondary cutting step S220, and a molding step S230. Each step will be described below.

[0041] [Discharge step S110] In the discharge step S110, biomass (e.g., EFB) is discharged from the oil palm oil mill 10. EFB is the residue of oil palm bunches that remains after the fruits are removed from the oil palm bunches in the oil mill 10. Therefore, when oil is extracted in the oil mill 10, EFB is sequentially discharged from the oil mill 10 as waste.

[0042] [Carry-in Step S120] In the carry-in step S120, the biomass discharged in the discharge step S110 is carried into the stockyard 20.

[0043] [Management Step S130] In the management step S130, the delivery date of the biomass delivered to the stockyard 20 is managed. In the management step S130, by managing the delivery date of the biomass delivered to the stockyard 20, it becomes possible to manage the freshness of the biomass.

[0044] The delivery date may also be, for example, the date on which the biomass is removed from the biomass generation site. The delivery date may also be, for example, the date on which the biomass (EFB) is discharged from the oil palm oil mill 10. As described above, the biomass fuel production system 100 according to this embodiment is installed near the oil palm oil mill 10. Therefore, transportation from the oil mill 10 to the stockyard 20 does not require a long time. Therefore, the delivery date generally coincides with the date on which the biomass is discharged from the oil palm oil mill 10. The freshness of the biomass discharged from the oil palm oil mill 10 is generally constant. Therefore, by using the date on which the biomass is discharged from the oil palm oil mill 10 as the delivery date, the freshness of the biomass can be managed with high accuracy.

[0045] The management step S130 is performed by, for example, the management device 110 described above.

[0046] [Discharge Step S140] In the discharge step S140, fresh biomass is discharged from the stockyard 20 based on the delivery date managed in the management step S130. This allows juice to be efficiently squeezed out of the biomass in the squeezing step S160, which will be described later.

[0047] Furthermore, in the unloading step S140, for example, it is preferable to unload biomass from the stockyard 20 within four days of the date of delivery, more preferably within three days of the date of delivery, and even more preferably within two days of the date of delivery. This allows juice to be squeezed out from the biomass more efficiently in the squeezing step S160. Note that biomass within four days of the date of delivery can also be said to be biomass that has been stored in the stockyard 20 for four days or less.

[0048] The dispensing step S140 is performed by, for example, the dispensing device 120 described above.

[0049] [Primary Cutting Step S150] In the primary cutting step S150, the biomass discharged in the discharging step S140 is primarily cut. The primary cutting step S150 is performed by, for example, the primary cutting device 130 described above.

[0050] [Compressing Step S160] In the compressing step S160, the biomass discharged in the discharging step S140 and primarily cut in the primary cutting step S150 is compressed to remove the squeezed juice (extract) from the biomass. This makes it possible to reduce the ash concentration remaining in the biomass after the second dehydration step S200 (described later) to a target value at low cost. The target value is the upper limit of the ash concentration required in a furnace that combusts biomass fuel. The target value is, for example, 2000 ppm.

[0051] The compressing step S160 is performed by, for example, the compressing device 140 described above.

[0052] It should be noted that the method for producing biomass fuel according to this embodiment does not include a heating step of heating the biomass before the pressing step S160. For example, in the method for producing biomass fuel according to this embodiment, the biomass is not heated from the time it is brought into the stockyard 20 until the time the pressing step S160 is performed. It should be noted that this heating is performed using either or both of electrical energy and combustion energy, and does not include the heating of the biomass caused by sunlight while it is stored in the stockyard 20. This makes it possible to reduce unnecessary energy used for heating.

[0053] Furthermore, in the pressing step S160, the moisture content of the biomass to be pressed is, for example, 50% by mass or more and 80% by mass or less. If the moisture content of the biomass to be pressed is less than 50% by mass, the amount of juice pressed from the biomass will be small due to low freshness. In this case, even if the subsequent steps from the first washing step S170 to the second dehydration step S200 are performed, the concentration of ash remaining in the biomass cannot be reduced to the target value. Furthermore, due to the nature of biomass, the moisture content of biomass will not exceed 80% by mass. Therefore, by setting the moisture content of the biomass to be pressed to 50% by mass or more and 80% by mass or less, the juice can be more efficiently pressed from the biomass in the pressing step S160.

[0054] Furthermore, in the compressing step S160, the compression force when compressing the biomass is, for example, 30 MPa or more and 60 MPa or less. If the compression force when compressing the biomass is less than 30 MPa, the degree of destruction of the biomass tissue is low, and the amount of juice squeezed out from the biomass is small. As a result, even if the subsequent steps from the first washing step S170 to the second dehydration step S200 are performed, the ash concentration remaining in the biomass cannot be reduced to the target value. On the other hand, if the compression force when compressing the biomass exceeds 60 MPa, the equipment cost of the compression device 140 increases. Therefore, by setting the compression force when compressing the biomass in the compressing step S160 to 30 MPa or more and 60 MPa or less, the biomass tissue can be efficiently destroyed, and the ash concentration remaining in the biomass after the second dehydration step S200 can be reduced to the target value at low cost.

[0055] [First Washing Step S170] In the first washing step S170, the biomass compressed in the compressing step S160 is washed with water, thereby allowing ash remaining in the biomass to be eluted into the water.

[0056] The first washing step S170 is performed, for example, by the first washing device 150 described above. In this case, in the first washing step S170, the bubbling unit 154 bubbles gas when washing the biomass with water. This allows the biomass to be loosened and stirred by the bubbled gas. This makes it possible to promote the elution (dissolution) of ash contained in the biomass into water. Therefore, compared to the conventional technology in which biomass is washed with only water without bubbling, more ash can be removed.

[0057] Furthermore, the bubbling unit 154 preferably bubbles the combustion exhaust gas after drying the biomass in the drying device 190. The combustion exhaust gas contains more carbon dioxide (CO ２) content is high. Therefore, the more the combustion exhaust gas is bubbled, the more the pH of the water used to wash the biomass can be lowered to 7 or less (for example, about pH 5 to pH 6). In other words, by bubbling the combustion exhaust gas, the water used to wash the biomass can be made acidic. The more acidic the washing water becomes, the more ash elutes, so by bubbling the combustion exhaust gas, it is possible to efficiently remove ash from the biomass.

[0058] One possible technique for lowering the pH of the water being washed is to add chemicals such as nitric acid or sulfuric acid. However, adding chemicals adds extra nitrogen and sulfur components to the biomass (biomass fuel) after washing. This generates nitrogen oxides (NOx) and sulfur oxides (SOx) when burned, so adding chemicals should be avoided as much as possible.

[0059] In response to this, the bubbling unit 154 bubbles a gas containing carbon dioxide, such as combustion exhaust gas, into the water used to wash the biomass, lowering the pH. This makes it possible to avoid the generation of air pollutants such as nitrogen oxides and sulfur oxides even when burning biomass fuel produced from the washed biomass. It also makes it possible to reduce the cost of chemicals.

[0060] Furthermore, the combustion exhaust gas after drying the biomass is at a temperature higher than room temperature (e.g., 25°C). Therefore, by bubbling the combustion exhaust gas with the bubbling unit 154, the temperature of the water can be raised above room temperature. The higher the temperature of the water used for washing, the faster the ash dissolution rate, making it possible to efficiently remove ash from the biomass.

[0061] [First Dehydration Step S180] In the first dehydration step S180, the biomass washed in the first washing step S170 is compressed to dehydrate the biomass, thereby further reducing the concentration of ash remaining in the biomass.

[0062] The first dehydration step S180 is performed by, for example, the first dehydration device 160 described above.

[0063] Furthermore, in the first dehydration step S180, the compression force when compressing the biomass is, for example, 30 MPa or more and 60 MPa or less. If the compression force when compressing the biomass is less than 30 MPa, the amount of waste liquid squeezed out from the biomass is small, and even if the subsequent second washing step S190 and second dehydration step S200 are performed, the ash concentration remaining in the biomass cannot be reduced to the target value. On the other hand, if the compression force when compressing the biomass exceeds 60 MPa, the equipment cost of the first dehydration device 160 increases. Therefore, by setting the compression force when compressing the biomass in the first dehydration step S180 to 30 MPa or more and 60 MPa or less, it is possible to reduce the ash concentration remaining in the biomass after the second dehydration step S200 to the target value at low cost.

[0064] [Second Washing Step S190] In the second washing step S190, the biomass dewatered in the first dewatering step S180 is washed with water, thereby allowing the ash remaining in the biomass to be further eluted into the water.

[0065] The second washing step S190 is performed, for example, by the second washing device 170 described above. In this case, in the second washing step S190, the bubbling unit 174 bubbles gas when washing the biomass with water. Therefore, similar to the first washing step S170 described above, it is possible to promote the dissolution of ash contained in the biomass into water. Also, similar to the bubbling unit 154 described above, it is preferable that the bubbling unit 174 bubbles the combustion exhaust gas after drying the biomass in the drying device 190. This makes it possible to lower the pH of the water used to wash the biomass to 7 or less. Therefore, it is possible to more efficiently remove ash from the biomass.

[0066] [Second Dehydration Step S200] In the second dehydration step S200, the biomass washed in the second washing step S190 is compressed to dehydrate the biomass, thereby further reducing the concentration of ash remaining in the biomass.

[0067] The second dehydration step S200 is performed by, for example, the second dehydration device 180 described above.

[0068] Furthermore, in the second dehydration step S200, the compression force when compressing the biomass is, for example, 30 MPa or more and 60 MPa or less. If the compression force when compressing the biomass is less than 30 MPa, the amount of waste liquid squeezed out from the biomass is small, and the ash concentration remaining in the biomass after the second dehydration step S200 cannot be reduced to the target value. On the other hand, if the compression force when compressing the biomass exceeds 60 MPa, the equipment costs for the second dehydration device 180 will increase. Therefore, by setting the compression force when compressing the biomass in the second dehydration step S200 to 30 MPa or more and 60 MPa or less, it is possible to reduce the ash concentration remaining in the biomass after the second dehydration step S200 to the target value at low cost.

[0069] [Drying Step S210] In the drying step S210, the biomass dewatered in the second dewatering step S200 is dried. The drying step S210 is performed by, for example, the drying device 190 described above.

[0070] [Secondary Cutting Step S220] In the secondary cutting step S220, the biomass dried in the drying step S210 is secondarily cut. The secondary cutting step S220 is performed by, for example, the secondary cutting device 200 described above.

[0071] [Molding Step S230] In the molding step S230, the biomass secondarily cut in the secondary cutting step S220 is molded. The molding step S230 is performed by, for example, the molding device 210 described above.

[0072] As described above, the biomass fuel production method according to this embodiment can efficiently remove ash from biomass by simply managing the date of delivery (freshness) of the biomass and compressing fresh biomass, without performing a heating step. Therefore, the biomass fuel production method according to this embodiment can produce biomass fuel with improved energy efficiency.

[0073] [Example 1] The potassium concentration in the squeezed juice obtained from the EFB of the example in the pressing step S160 was measured. The EFB of the example was EFB delivered within four days. As a result, it was confirmed that the potassium concentration in the squeezed juice of the EFB of the example was approximately the same.

[0074] [Example 2] The amount of juice obtained in the squeezing step S160 (squeezed juice amount) and the amount of potassium remaining in the EFB after squeezing (residual potassium amount) were measured for the EFB of the example and the EFB of the comparative example. The EFB of the comparative example was an EFB that had been delivered for 5 days or more, to which water was added and then left overnight.

[0075] Figure 3 is a graph showing the relationship between the amount of squeezed juice and the amount of residual potassium. The horizontal axis of Figure 3 represents the amount of squeezed juice per unit mass of EFB. The vertical axis of Figure 3 represents the amount of residual potassium per unit mass of EFB. In Figure 3, white squares represent EFBs of Examples, and black squares represent EFBs of Comparative Examples.

[0076] As shown in Figure 3, it was confirmed that the residual potassium amount decreased with increasing amount of squeezed juice in the EFB of the Example. On the other hand, it was confirmed that the residual potassium amount could not be reduced to the same level as that of the EFB of the Example unless the amount of squeezed juice in the EFB of the Comparative Example was larger than that of the EFB of the Example.

[0077] From the above results, it was confirmed that even if the moisture content during the pressing step S160 is about the same, the amount of residual potassium does not decrease unless the freshness is high.

[0078] [Example 3] The amount of residual potassium was measured for the EFB of the example when the first cleaning step S170 was performed after the pressing step S160, and when the first cleaning step S170 was performed without the pressing step S160. The compression force in the pressing step S160 was set to 30 MPa and 60 MPa.

[0079] As a result, the amount of residual potassium when the compressing force was 30 MPa was about the same as when the first washing step S170 was performed without performing the squeezing step S160.

[0080] On the other hand, it was confirmed that the amount of residual potassium when the compressive force was 60 MPa was lower than the amount of residual potassium when the compressive force was 30 MPa.

[0081] From the above results, it was confirmed that the amount of residual potassium can be reduced by setting the compression force when compressing the biomass in the compression step S160 to 30 MPa or more.

[0082] Example 4 The amounts of sparingly soluble potassium and readily soluble potassium contained in the EFB of the example when the compressing step S160 was performed were calculated by simulation. The amounts and dissolution rates of sparingly soluble potassium and readily soluble potassium contained in the EFB of the example when the compressing step S160 was not performed were also calculated by simulation. The compressing forces in the compressing step S160 were set to 30 MPa and 60 MPa.

[0083] Figure 4 is a graph showing the amounts of poorly soluble potassium and readily soluble potassium when no compression is performed, and when compression forces are applied of 30 MPa and 60 MPa. Figure 5 is a graph showing the dissolution rates of poorly soluble potassium and readily soluble potassium when no compression is performed, and when compression forces are applied of 30 MPa and 60 MPa. In Figures 4 and 5, white squares represent readily soluble potassium, and black squares represent poorly soluble potassium.

[0084] As shown in Figure 4, it was confirmed that when the compression force was 30 MPa, the EFB contained sparingly soluble potassium at a rate similar to that when no compression was performed. On the other hand, when the compression force was 60 MPa, it was confirmed that the amount of sparingly soluble potassium contained in the EFB decreased and the amount of readily soluble potassium increased compared to when the compression force was 30 MPa.

[0085] 5, it was confirmed that the dissolution rates of both sparingly soluble potassium and readily soluble potassium increased when the compressive force was 30 MPa compared to when no compression was performed. It was also confirmed that the dissolution rate of readily soluble potassium increased further when the compressive force was 60 MPa compared to when the compressive force was 30 MPa.

[0086] Although the embodiments have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to the above-described embodiments. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0087] For example, in the above embodiment, EFB is used as an example of biomass. This allows for the effective use of EFB, which would have been discarded in the past. However, the biomass may also be OPT (Oil Palm Trunk, discarded old oil palm trees) left behind in palm plantations. This allows for the effective use of OPT, which would have been discarded in the past. Furthermore, when the biomass is OPT, the delivery date may be, for example, the date on which the OPT is transported from the palm plantation. The freshness of OPT transported from the palm plantation is generally constant. Therefore, by using the date on which the OPT is transported from the palm plantation as the delivery date, the freshness of the OPT can be managed with high precision.

[0088] Furthermore, the biomass may be herbaceous biomass, woody biomass, or agricultural waste biomass. Herbaceous biomass is, for example, biomass derived from bamboo, rice, or Japanese silver grass. Rice-derived biomass is, for example, sorghum. Woody biomass is wood, sawdust, bark, etc. Agricultural waste biomass is, for example, bagasse, palm kernel shell (PKS), etc.

[0089] In the above embodiment, the delivery date is the date on which the biomass is discharged from the oil palm oil mill 10. However, the delivery date may be the date on which the biomass is harvested. Alternatively, the delivery date may be the date on which fruits are extracted from the oil palm bunches at the oil palm oil mill 10.

[0090] In the above embodiment, the second cleaning step S190 and the second spin-drying step S200 are performed in addition to the first cleaning step S170 and the first spin-drying step S180. However, the second cleaning step S190 and the second spin-drying step S200 may be omitted depending on the target value.

[0091] It should be noted that the steps in the biomass fuel production method of this specification do not necessarily have to be processed in chronological order according to the order described in the flowchart, and may include parallel or subroutine processing.

[0092] The present disclosure can contribute, for example, to Sustainable Development Goals (SDGs) Goal 7 "Ensure access to affordable, reliable, sustainable and modern energy," Goal 13 "Take urgent action to combat climate change and its impacts," and Goal 15 "Sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss."

[0093] 10: Oil extraction plant 20: Stockyard 100: Biomass fuel production system 110: Management device 120: Discharge device 140: Compression device 150: First washing device (washing device) 160: First dehydration device (dehydration device) 170: Second washing device 180: Second dehydration device

Claims

1. A method for producing biomass fuel, comprising: a management process for managing the delivery date of biomass brought into a stockyard; a discharge process for discharging the biomass from the stockyard based on the delivery date; a squeezing process for removing juice from the biomass by squeezing the biomass discharged in the discharge process; a first washing process for washing the biomass compressed in the squeezing process with water; and a first dehydration process for dehydrating the biomass by squeezing the biomass washed in the first washing process.

2. The method for producing biomass fuel according to claim 1, which does not include a heating step of heating the biomass before carrying out the pressing step.

3. A method for producing biomass fuel as described in claim 1 or 2, wherein in the unloading step, the biomass is unloaded from the stockyard within four days from the date of delivery.

4. A method for producing biomass fuel as described in claim 1 or 2, wherein in the pressing step, the moisture content of the biomass to be pressed is 50 mass% or more and 80 mass% or less.

5. A method for producing biomass fuel as described in claim 1 or 2, wherein the compressive force used to compress the biomass in the compressing step is 30 MPa or more and 60 MPa or less.

6. A method for producing biomass fuel as described in claim 1 or 2, wherein the biomass is EFB produced during oil palm oil extraction, and the date of delivery is the date on which the EFB is discharged from the oil palm oil extraction factory.

7. The method for producing biomass fuel according to claim 1 or 2, wherein the biomass is OPT left in a palm plantation, and the date of delivery is the date on which the OPT is removed from the palm plantation.

8. A method for producing biomass fuel as described in claim 1 or 2, further comprising: a second washing step of washing the biomass dehydrated in the first dehydration step with water; and a second dehydration step of dehydrating the biomass by squeezing the biomass washed in the second washing step.

9. A biomass fuel production system comprising: a management device that manages the delivery dates of biomass brought into a stockyard; an unloading device that unloads the biomass from the stockyard based on the delivery date; a squeezing device that removes juice from the biomass by squeezing the biomass unloaded by the unloading device; a washing device that washes with water the biomass compressed by the squeezing device; and a dehydration device that dehydrates the biomass by squeezing the biomass washed by the washing device.

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