Biofuel production method

Abstract

To provide a biofuel production method that does not require pH adjustment as pretreatment.SOLUTION: A biofuel production method according to the present disclosure includes a step (step S104) of mixing a terrestrial-derived raw material, i.e., a terrestrial biomass 30, with a marine-derived raw material, i.e., a marine biomass 20, and a step (step S105) of performing fermentation using the mixed raw material to produce ethanol.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing biofuel. [Background technology]

[0002] When producing biomass fuel, it is necessary to increase productivity, such as the yield and rate of the target product, in accordance with the characteristics of the biomass used. For example, Patent Document 1 discloses a technique for improving productivity, such as parallel side fermentation, which uses lignocellulose, a type of terrestrial biomass, and adjusts the saccharification process to an optimal state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-039295 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors have found the following problems with respect to biofuel production methods. In the technology disclosed in Patent Document 1, pH adjustment is performed as a pretreatment depending on the biomass feedstock. However, from the perspective of improving life cycle assessment (LCA), there has been a demand for the development of a biofuel production method that does not require pH adjustment as a pretreatment.

[0005] The present disclosure has been made in consideration of such problems, and aims to provide a method for producing biofuel that does not require pH adjustment as a pretreatment. [Means for solving the problem]

[0006] One aspect of the present invention to achieve the above object is to 1. A method for producing biofuel, comprising: mixing a terrestrially derived raw material with a marine-derived raw material; and a step of fermenting the mixed raw material to produce ethanol. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a method for producing biofuel that does not require pH adjustment as a pretreatment. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is an enlarged schematic view of an example of mixed biomass according to an embodiment. [Figure 2] 1 is a flowchart showing an example of a biofuel production method according to an embodiment. [Figure 3] 1 is a graph showing an example of the surface potential and particle diameter of biomass. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or corresponding elements are designated by the same reference numerals, and for clarity of explanation, duplicate explanations will be omitted as necessary. In addition, for ease of understanding, the scale of each part in the drawings may differ from the actual scale.

[0010] First, referring to Figure 1, an example of the configuration of the mixed biomass used in the biofuel production method according to this embodiment, i.e., the mixed biomass according to this embodiment, will be described. The mixed biomass 10 according to this embodiment is a mixture produced using multiple biomass raw materials and is suitable for ethanol brewing. As shown in Figure 1, the mixed biomass includes marine biomass 20 (20a, 20b, 20c, 20d) and terrestrial biomass 30.

[0011] The marine biomass 20 is a raw material of marine origin. The marine biomass 20 is produced using, for example, seaweed. The terrestrial biomass 30 is a raw material of terrestrial origin. The terrestrial biomass 30 is produced using, for example, bamboo or sugarcane. The marine biomass 20 and the terrestrial biomass 30 have different particle sizes. There is no particular limitation on the method for measuring the particle sizes of the terrestrial biomass 30 and the marine biomass 20. The particle sizes of the terrestrial biomass 30 and the marine biomass 20 may be measured as, for example, a median diameter. For example, the median particle size diameter of the marine biomass 20 may be about ¼ that of the terrestrial biomass 30.

[0012] 1 illustrates a case where the marine biomass 20 has a smaller particle size than the terrestrial biomass 30. However, the marine biomass 20 may have a larger particle size than the terrestrial biomass 30. Because the marine biomass 20 and the terrestrial biomass 30 have different particle sizes, the marine biomass 20 and the terrestrial biomass 30 are more uniformly mixed and composited than if the marine biomass 20 and the terrestrial biomass 30 had approximately the same particle size.

[0013] The marine biomass 20 and the terrestrial biomass 30 are made of different materials and therefore usually have different pH values. Therefore, the pH of the mixed biomass 10 can be adjusted by adjusting the ratio of the mixed marine biomass 20 and terrestrial biomass 30. Furthermore, since the mixed biomass 10 is a composite of the marine biomass 20 and the terrestrial biomass 30, there is no internal pH imbalance. Therefore, the mixed biomass 10 as a whole has a target pH suitable for ethanol fermentation. The mixing ratio of the marine biomass 20 and the terrestrial biomass 30 is determined so that the pH of the mixed biomass 10 is, for example, about 5 to 8.

[0014] Next, the flow of the biofuel production method according to this embodiment will be described with reference to Figure 2. In the biofuel production method according to this embodiment, first, the marine biomass 20 and the terrestrial biomass 30 are pulverized (step S101). In step S101, the marine biomass 20 and the terrestrial biomass 30 are pulverized to predetermined particle sizes, i.e., different particle sizes. Specifically, for example, the marine biomass 20 may be pulverized to a median particle size diameter of 100 µm or more and 300 µm or less. The terrestrial biomass 30 may be pulverized to a median particle size diameter of 300 µm or more.

[0015] Next, the characteristics of the marine biomass 20 and the terrestrial biomass 30 are measured (step S102). Specifically, in step S102, the pH of each of the marine biomass 20 and the terrestrial biomass 30 is measured. Based on the pH measurement results in step S102, the mixing ratio of the marine biomass 20 and the terrestrial biomass 30, etc., is determined. In step S102, it is also preferable to measure the electric charges of each of the marine biomass 20 and the terrestrial biomass 30. Based on the electric charge measurement results in step S102, it may be determined whether or not static elimination processing of the marine biomass 20 and the terrestrial biomass 30 is necessary.

[0016] Next, at least one of the marine biomass 20 and the terrestrial biomass 30 may be de-electrified (step S103). Step S103 may be performed when it is determined in step S102 that de-electrification processing is necessary. In the example shown in FIG. 1, step S103 is performed after step S102, but step S103 may be performed in parallel with step S102 or may be performed before step S102. The means for de-electrification is not particularly limited, and may be, for example, de-electrified by electrostatic adsorption using an ionizer.

[0017] FIG. 3 shows the relationship between the surface potential and particle size of each biomass when only the terrestrial biomass 30 is destaticized. In the example shown in FIG. 3, the terrestrial biomass 30 has a larger particle size than the marine biomass 20. Therefore, in order to reduce the amount of energy required for destaticization, only the terrestrial biomass 30 is destaticized in the example shown in FIG. 3. The terrestrial biomass 30 is usually positively charged. Therefore, by destaticizing using an ionizer, the terrestrial biomass 30 is brought closer to electrical neutrality. The marine biomass 20 is also usually positively charged. By performing step S103, the marine biomass 20 and the terrestrial biomass 30 can be more uniformly mixed and composited due to the charging caused by the potential difference between the marine biomass 20 and the terrestrial biomass 30.

[0018] 3, only the terrestrial biomass 30 is neutralized, but only the marine biomass 20 may be neutralized, or both the marine biomass 20 and the terrestrial biomass 30 may be neutralized. Furthermore, in order to further strengthen the particle combination, the terrestrial biomass 30 may be negatively charged and the marine biomass 20 may be uniformly positively charged. In this case, the electrostatic bond between the terrestrial biomass 30 and the marine biomass 20 becomes stronger.

[0019] Returning to Figure 2, the explanation continues. Next, the marine biomass 20 and the terrestrial biomass 30 are mixed (step S104). In step S104, the marine biomass 20 and the terrestrial biomass 30 are mixed in a mixing ratio determined based on the pH measured in step S102 to form a mixed biomass 10. Because the marine biomass 20 and the terrestrial biomass 30 have different particle sizes, the mixed biomass 10 is a composite in which the marine biomass 20 and the terrestrial biomass 30 are uniformly mixed. Therefore, the mixed biomass 10 does not have a bias in pH.

[0020] Generally, biomass contains various components, and these components are often localized. Because the charging characteristics change depending on the content ratio and localization of the components, simply mixing different biomass particles often results in particles coming into contact with each other and exerting a positive electrical influence on each other, causing particle aggregation, etc. Therefore, in order to reliably combine different biomass particles, it is preferable to adjust the charging state of each biomass before mixing them.

[0021] Next, ethanol is produced by fermenting the mixed biomass 10 (step S105). In step S105, typically, a saccharification step using an enzymatic reaction is performed followed by a fermentation step using yeast. The detailed procedure for performing step S105 may be performed by a known method. In the biofuel production method according to this embodiment, the pH of the mixed biomass is adjusted by mixing marine biomass 20 and terrestrial biomass 30. Therefore, it is possible to prepare a mixed biomass with a pH suitable for the saccharification step and the fermentation step without adding an alkali or acid to the mixed biomass. In this way, the biofuel production method according to this embodiment does not require pH adjustment as a pretreatment. This improves LCA and reduces production costs.

[0022] Furthermore, in the biofuel production method according to this embodiment, the marine biomass 20 and the terrestrial biomass 30 are combined, and therefore the reactions in the saccharification and fermentation processes proceed while maintaining a predetermined overall pH. As a result, reaction inhibition due to local alkalinity or local acidity does not occur in each process, and ethanol can be produced efficiently.

[0023] The present disclosure is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the present disclosure. [Explanation of symbols]

[0024] 10 Mixed Biomass 20 Marine Biomass 30 Terrestrial biomass

Claims

1. mixing a terrestrially derived raw material with a marine-derived raw material; and a step of fermenting the mixed raw material to produce ethanol. Biofuel production methods.

2. The median particle size of the terrestrially derived raw material is 300 μm or more; The median particle size of the marine-derived raw material is 100 μm or more and 300 μm or less. The method for producing biofuel according to claim 1 .

3. The method further includes a step of destaticizing at least one of the terrestrial-derived raw material and the marine-derived raw material prior to the mixing step. The method for producing biofuel according to claim 1 or 2.

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