Biodiesel fuel production plant

Abstract

To provide a biodiesel fuel production plant that can perform production of biodiesel fuel and production of nutrient source required for heterotrophic culture of euglena in the same facility, and is capable of being self-sufficient of the biodiesel fuel.SOLUTION: A biodiesel fuel production plant according to the present invention comprises: a hydroponics unit which performs hydroponics of rice plant by using sunlight as an energy source; an euglena culture unit which performs heterotrophic culture of euglena in a culture tank by using saccharide obtained by degenerating rice cropped by the hydroponics unit; and a fuel generating unit which generates biodiesel fuel from euglena cultured by the euglena culture unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a biodiesel fuel production plant that produces biodiesel fuel using Euglena.

Background Art

[0002] In recent years, in order to reduce CO2, which is considered to be one of the causes of global warming, the use of biofuels is expected to expand as an alternative fuel to petroleum fuels. For example, attempts have been made to replace part of the gas oil used in trucks, buses, ships, etc. with a biofuel called biodiesel fuel. As a method for producing biodiesel fuel, a method of using animal and vegetable oils as raw materials and removing glycerin by an ester exchange reaction is common, but various methods of using wax esters obtained by culturing Euglena instead of animal and vegetable oils have also been studied.

[0003] For example, Patent Documents 1 and 2 describe methods for producing wax esters by culturing Euglena. Patent Document 1 describes that when Euglena is cultured under aerobic conditions and then held under anaerobic conditions, paramylon, which is a storage polysaccharide, is decomposed to produce wax esters composed of fatty acids and fatty alcohols. Further, Patent Document 2 describes that by culturing Euglena aerobically and then adding a carbon source such as glucose or fructose to the culture solution and culturing under heterotrophic conditions before holding under anaerobic conditions, Euglena with a high content of wax esters can be produced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] To reduce the production cost of biodiesel fuel using Euglena, it is necessary to maximize the efficiency of wax ester production through Euglena cultivation. Therefore, heterotrophic cultivation, as described in Patent Document 2, can be considered as a method for culturing Euglena. When performing heterotrophic cultivation, it is necessary to add sugar sources such as glucose to the culture medium, but when producing biodiesel fuel on a certain scale, the amount of sugar source used becomes large, and procuring the sugar source requires time and cost.

[0006] Therefore, the present invention aims to provide a biodiesel fuel production plant that enables self-sufficiency in biodiesel fuel by allowing the production of biodiesel fuel and the production of nutrients necessary for heterotrophic cultivation of Euglena to be carried out in the same facility. [Means for solving the problem]

[0007] The biodiesel fuel production plant according to the present invention comprises a hydroponic cultivation unit that performs hydroponic cultivation of rice using sunlight as an energy source, a Euglena cultivation unit that performs heterotrophic cultivation of Euglena in a culture tank using sugars obtained by decomposing the rice harvested in the hydroponic cultivation unit, and a fuel production unit that produces biodiesel fuel from the Euglena cultivated in the Euglena cultivation unit. [Effects of the Invention]

[0008] According to the present invention, the production of biodiesel fuel and the production of nutrients necessary for heterotrophic cultivation of Euglena can be carried out in the same facility, and a biodiesel fuel production plant that enables self-sufficiency in biodiesel fuel can be provided. [Brief explanation of the drawing]

[0009] [Figure 1] Block diagram showing the schematic configuration of a biodiesel fuel production plant according to this embodiment. [Figure 2]Block diagram showing the schematic configuration of a biodiesel fuel production plant according to a modified example. [Modes for carrying out the invention]

[0010] (Embodiment) Figure 1 is a block diagram showing the schematic configuration of a biodiesel fuel production plant according to an embodiment.

[0011] The biodiesel fuel production plant 100 is a facility that produces biodiesel fuel from wax esters obtained from cultivating Euglena (a type of microalgae), and comprises a hydroponic cultivation unit 1, a Euglena cultivation unit 2, a fuel production unit 3, solar lighting 4, solar panels 5, and a storage battery 6.

[0012] <Hydroponic cultivation unit 1> Hydroponic cultivation unit 1 is a unit that produces rice, which is a nutrient source (raw material for sugar) necessary for the heterotrophic cultivation of Euglena, and uses sunlight as an energy source to hydroponically cultivate rice. Hydroponic cultivation unit 1 has multiple cultivation shelves 11, multiple LED lights 12, a solution tank 13, a pump 14, and an air conditioning unit 15. Hydroponic cultivation unit 1 is configured as a closable room or chamber, and the cultivation shelves 11, LED lights 12, solution tank 13, pump 14, and air conditioning unit 15 are housed inside.

[0013] The cultivation shelf 11 is the part for cultivating rice and has a retaining material for holding the rice plants. The retaining material is made of a water-absorbing material such as urethane foam. The retaining material has pre-made slits and holes, and when sowing, rice seeds that have already rooted and germinated are inserted into the slits and holes. The retaining material is immersed in a cultivation solution containing nutrients and trace elements for growing rice, and the rice plants can absorb the cultivation solution through the retaining material. To increase the yield per unit area, it is preferable to arrange multiple cultivation shelves 11 in multiple tiers, stacked vertically at predetermined intervals.

[0014] The LED lights 12 are installed above each of the cultivation shelves 11, corresponding to each shelf, and illuminate the cultivation shelves 11 with light.

[0015] The solution tank 13 stores an aqueous solution (cultivation solution) containing various nutrients and trace elements necessary for hydroponic rice cultivation. The solution tank 13 is appropriately equipped with adjustment devices for adjusting fertilizer concentration, pH, temperature, etc., and stirring devices for agitating the stored cultivation solution.

[0016] The pump 14 is connected to the solution tank 13 and the cultivation shelf 11 via predetermined piping, and supplies the cultivation solution from the solution tank 13 to the cultivation shelf 11. On-off valves and check valves are appropriately provided along the piping, and by controlling the opening and closing of the on-off valves with a control device (not shown), a state is maintained in which the holding members of the cultivation shelf 11 absorb a certain amount of cultivation solution.

[0017] The air conditioning unit 15 adjusts the temperature and humidity inside the hydroponic cultivation unit 1 to conditions suitable for rice cultivation.

[0018] The biodiesel fuel production plant 100 according to this embodiment is equipped with a solar light source 4. One end of the light guide of the solar light source 4 is positioned above the cultivation shelves 11 of the hydroponic cultivation unit 1, so that sunlight collected by the solar light source 4 can be irradiated onto the cultivation shelves 11 during daylight hours. A light guide tube or optical fiber can be used as the light guide. When the biodiesel fuel production plant 100 is equipped with a solar light source 4, rice can be cultivated using the collected sunlight during daylight hours, thus reducing the cost required for the LED light source 12. At night when there is no sunlight, or on cloudy days when the amount of light is insufficient, the LED light source 12 can be used to irradiate the rice being cultivated with light 24 hours a day.

[0019] The rice variety cultivated in the hydroponic cultivation unit 1 is not particularly limited, but it is preferable to use a variety with a short plant height so that cultivation in a space-saving manner is possible. For example, the registered variety "Mizuno Yume" has a plant height of 20 cm or less, and is particularly suitable for a cultivation method in which the cultivation shelves 11 are stacked vertically in multiple stages. By optimizing the wavelength of the LED lighting 12 and the composition of the cultivation solution, and irradiating the LED lighting 12 for 24 hours, it becomes possible to harvest rice in about two months. By enabling six cropping seasons through optimization of cultivation conditions, it is possible to produce rice, which is a raw material for the sugar required for the cultivation of Euglena, in a space-saving and highly efficient manner.

[0020] The rice harvested in the hydroponic cultivation unit 1 is transported to a saccharification facility 8 provided at a location separate from the biodiesel fuel production plant 100, and is converted into sugar (glucose) using a saccharification device 9 in the saccharification facility. The method of saccharification is not particularly limited, and known methods such as enzymatic treatment and fermentation methods can be used. Further, the cellulose of rice straw and rice husks may be decomposed by enzymatic treatment, fermentation methods, etc. and converted into glucose. The sugar obtained by saccharification in the saccharification facility 8 is carried into the Euglena culture unit 2 and used as a nutrient for Euglena.

[0021] In addition, the technologies disclosed in JP-A-2021-185873, JP-A-2021-185874, and JP-A-2021-187719 can be applied to the hydroponic cultivation in the hydroponic cultivation unit 1.

[0022] <Euglena culture unit 2> The Euglena culture unit 2 is a unit for performing heterotrophic culture of Euglena using the sugar obtained by decomposing the rice harvested in the hydroponic cultivation unit 1 in the saccharification facility 8. The Euglena culture unit 2 includes a culture tank 21, a culture solution supply device 22, and a concentrate recovery device 23.

[0023] The culture tank 21 may be appropriately equipped with a stirring device or submersible pump for stirring the culture medium, a refractometer, a pH meter, a dissolved oxygen meter, a dissolved carbon dioxide meter, a water thermometer, a heater or chiller for adjusting the temperature of the culture medium, etc. It is preferable that the Euglena culture unit 2 be provided with multiple culture tanks 21. If cultivation is performed in only one culture tank 21, if the cultivation fails, the entire culture medium that has been set up will be wasted. In contrast, if Euglena is cultured in multiple culture tanks 21, the risk of the entire amount of culture medium being wasted can be reduced even if the cultivation in one of the culture tanks 21 fails. When multiple culture tanks 21 are provided in the Euglena culture unit 2, it is preferable to stagger the start dates of the cultivation. For example, if the cultivation period is 6 days, by providing 6 culture tanks 21 and performing cycle cultivation with the start dates staggered by one day each, the possibility of cultivation failure in multiple culture tanks 21 can be further reduced.

[0024] The culture medium supply device 22 supplies the culture tank 21 with a culture medium containing sugars derived from rice harvested in the hydroponic cultivation unit 1 and various nutrients necessary for culturing Euglena.

[0025] The concentrated liquid recovery device 23 filters the culture medium after cultivation is complete and recovers a concentrated liquid containing a high concentration of Euglena. The concentrated liquid recovery device 23 sends the recovered concentrated liquid to the fuel production unit 3 through piping (not shown). More specifically, in the final stage of cultivation, the stirring device and submersible pump of the culture tank 21 are stopped, and cultivation is carried out in a static state for a predetermined time (e.g., 24 hours) to allow Euglena to settle at the bottom of the culture tank 21. The concentrated liquid recovery device 23 recovers the concentrated liquid by filtering and withdrawing the culture medium containing the settled Euglena. The concentrated liquid recovery device 23 may also circulate the filtered culture medium back into the culture tank 21 or a culture medium tank (not shown). By reusing the filtered culture medium, the amount of water used can be reduced.

[0026] <Fuel Manufacturing Unit 3> The fuel production unit 3 generates biodiesel fuel from Euglena cultured in the Euglena cultivation unit 2. The fuel production unit 3 includes a centrifuge 31, a fuel conversion device 32, and a storage tank 33.

[0027] The centrifuge 31 centrifuges the concentrated Euglena liquid recovered by the concentrated liquid recovery device 23.

[0028] The fuel production unit 32 extracts wax esters from centrifuged Euglena and produces biodiesel fuel through a transesterification reaction between the extracted wax esters and alcohol. Methanol or ethanol can be used as the alcohol in the transesterification reaction. The fuel production unit 32 purifies the biodiesel fuel from the reaction solution of the transesterification reaction by distillation or other means, and stores the purified biodiesel fuel in the storage tank 33.

[0029] The biodiesel fuel production plant 100 according to this embodiment further comprises a solar panel 5, a storage battery 6, and a generator 7.

[0030] The solar panels 5 are located outside the building of the biodiesel fuel production plant 100 and supply the generated electricity to the electrical equipment inside the biodiesel fuel production plant 100. It is preferable to use solar panels 5 with the highest possible conversion efficiency so that they can meet the electricity consumption of the biodiesel fuel production plant 100. Furthermore, it is preferable to install the solar panels 5 over as large an area as possible, utilizing the space on the roof of the biodiesel fuel production plant 100. By providing solar panels 5, it becomes possible to cultivate rice in the hydroponic cultivation unit 1 with reduced energy consumption.

[0031] Any surplus electricity generated by the solar panel 5 is stored in the battery 6. In this embodiment, when the solar lighting 4 is installed together with the solar panel 5, during periods of sufficient sunlight, the light collected by the solar lighting 4 can be used to illuminate the cultivation shelves 11, while the surplus electricity generated by the solar panel 5 is stored in the battery 6. During periods of insufficient sunlight, such as at night or on cloudy days, the electricity stored in the battery 6 can be supplied to the LED lighting 12, enabling 24-hour light irradiation of the rice plants.

[0032] If the solar panels 5 and storage battery 6 cannot supply the electricity necessary to operate the biodiesel fuel production plant 100, electricity can be supplied by operating the generator 7. The electricity generated by the generator 7 may also be used to charge the storage battery 6. The generator 7 is preferably a diesel generator, in which case it can generate electricity using biodiesel fuel stored in the storage tank 33.

[0033] Furthermore, since the amount of electricity generated by the solar panels 5 is affected by the season and weather, it is preferable to connect the biodiesel fuel production plant 100 to the commercial power supply in order to ensure a stable supply of electricity.

[0034] The biodiesel fuel production plant 100 may further include one or both of the CO2 emission device 24 and the O2 supply device 25.

[0035] The CO2 emission device 24 can discharge air with a relatively high CO2 concentration generated in the culture tank 21 and supply it to the hydroponic cultivation unit 1. By installing the CO2 emission device 24, the CO2 generated in the culture tank 21 can be used for hydroponic rice cultivation, thereby reducing CO2 emissions.

[0036] The O2 supply device 25 can discharge air with a relatively high oxygen concentration, generated by photosynthesis within the hydroponic cultivation unit 1, and supply it to the culture tank 21. By providing the O2 supply device 25, the oxygen generated in the hydroponic cultivation unit 1 can be effectively utilized whenever oxygen is required at any stage of heterotrophic cultivation of Euglena.

[0037] The following describes a method for producing biodiesel fuel using the biodiesel fuel production plant 100.

[0038] In the hydroponic cultivation unit 1, rice seeds are sown on the cultivation shelves 11. As described above, sowing is performed by inserting rice seeds, which have been disinfected and soaked in water to induce rooting and germination, into the holes and slits of the holding material of the cultivation shelves 11. Subsequently, a computer is used to monitor various parameters using various sensors such as thermometers, hygrometers, and pH meters installed in the hydroponic cultivation unit 1, and controls the temperature, humidity, temperature of the cultivation solution, and the supply rate of the cultivation solution to the cultivation shelves 11 to achieve predetermined cultivation conditions, and cultivation is performed for a predetermined period (e.g., 60 days). After the cultivation period has elapsed and the rice ears have ripened, the rice is harvested. The setting of the rice seeds on the cultivation shelves 11 and the harvesting of the rice are done manually, but they may also be automated using machinery. The harvested rice is transported to the saccharification facility 8, where the rice is converted into sugar (glucose) using the saccharification device 9. The obtained sugar may also be stored in a storage tank (not shown) that can also be received by the Euglena cultivation unit 2. Furthermore, the sugar obtained from the saccharification apparatus 9 may be stored in solid or liquid form.

[0039] In Euglena cultivation unit 2, heterotrophic culture of Euglena is performed. After adding the culture medium to the culture tank 21, Euglena is added. The culture medium contains sugar, nitrogen source, phosphorus source, minerals, etc. Then, the culture medium is stirred using a stirring device or submersible pump. Subsequently, various parameters are monitored using various sensors installed in the culture tank 21, such as a refractometer, pH meter, dissolved oxygen meter, dissolved carbon dioxide meter, and water thermometer, using a computer. Sugar content, pH, water temperature, residual O2 concentration, residual CO2 concentration, etc. are controlled to achieve predetermined culture conditions, and cultivation is performed for a predetermined period. Heterotrophic culture of Euglena may be performed under anaerobic conditions, aerobic conditions, or a combination of aerobic and anaerobic conditions. In addition, oxygen or carbon dioxide may be supplied to the culture tank as needed during heterotrophic culture. After the cultivation period has elapsed, stirring of the culture medium is stopped, and the cultured Euglena is allowed to settle. As described above, if the Euglena culture unit 2 is equipped with multiple culture tanks 21, it is preferable to stagger the start of culture by one day each. Known methods can be used as the heterotrophic culture method for Euglena.

[0040] The cultivation of rice in hydroponic unit 1 and the cultivation of Euglena in Euglena cultivation unit 2 can be carried out in parallel.

[0041] In the fuel production unit 3, biodiesel fuel is produced each time the cultivation of Euglena is completed in the Euglena cultivation unit 2. In the fuel production unit 3, Euglena is centrifuged from the concentrated Euglena liquid recovered from the cultivation tank 21, wax esters are extracted from the separated Euglena, a transesterification reaction is carried out between the wax esters and alcohol, and then the biodiesel fuel is refined and stored in the storage tank 33.

[0042] As described above, the biodiesel fuel production plant 100 according to this embodiment includes a hydroponic cultivation unit 1 for cultivating rice, located within the same facility as the Euglena cultivation unit 2 and fuel production unit 3 for heterotrophic cultivation of Euglena. Therefore, glucose can be cultivated using sugars obtained by decomposing rice harvested in the hydroponic cultivation unit 1, without having to separately purchase the nutrients necessary for heterotrophic cultivation of Euglena. Thus, according to the biodiesel fuel production plant 100 according to this embodiment, it is possible to achieve self-sufficiency in biodiesel fuel using Euglena.

[0043] Furthermore, in hydroponic cultivation unit 1, rice can be cultivated with extremely high efficiency by arranging cultivation shelves 11 in multiple tiers and providing 24-hour light irradiation using LED lighting 12. In other words, compared to cultivation in paddy fields, hydroponic cultivation unit 1 can dramatically increase the amount of rice harvested per unit period (e.g., one year), and therefore the yield of sugar obtained from the harvested rice is also increased. The increased sugar yield allows for an increase in the amount of Euglena that can be cultivated, thereby improving the production volume of biodiesel fuel.

[0044] Furthermore, by combining the highly efficient rice cultivation using the hydroponic cultivation unit 1 with the highly efficient production of wax esters through heterotrophic cultivation, it becomes possible to reduce the cost required for the production of biodiesel fuel. As in this embodiment, when solar panels 5 are installed, at least a portion of the electricity required to operate the biodiesel fuel production plant 100 can be supplied, thereby further reducing the cost of biodiesel fuel production.

[0045] (modified version) Figure 2 is a block diagram showing the schematic configuration of a biodiesel fuel production plant according to a modified example.

[0046] The modified biodiesel fuel production plant 101 differs from the biodiesel fuel production plant 100 shown in Figure 1 in that it has a saccharification device 9 for converting harvested rice into sugar located within the same facility. While installing the saccharification device 9 within the plant, as in the modified example, incurs costs for its installation, it is more advantageous from the standpoint of self-sufficiency in biodiesel fuel because sugar can be produced within the plant without transporting the harvested rice.

[0047] The biodiesel fuel production plants 100 and 101 according to the present invention are preferably installed on the premises of companies that use vehicles, such as transportation companies, bus companies, taxi companies, and construction companies, or on the premises of companies that use ships or in port areas. In this case, the biodiesel fuel produced by the biodiesel fuel production plants 100 and 101 can be easily provided to consumers. The biodiesel fuel production plants 100 and 101 according to the present invention are equipped with a hydroponic cultivation unit 1 that produces nutrients necessary for heterotrophic cultivation of Euglena, in addition to the Euglena cultivation unit 2 and the fuel production unit 3. Therefore, almost all the components necessary for producing biodiesel fuel using Euglena are available, and operation after construction near consumers of biodiesel fuel is easy. [Industrial applicability]

[0048] This invention can be used as a plant for producing biodiesel fuel. [Explanation of symbols]

[0049] 1 Hydroponic cultivation unit 2. Euglena culture unit 3. Fuel Production Unit 4. Solar lighting 5. Solar panels 6. Storage Battery 12 LED lights 21 Culture tank

Claims

1. A hydroponic cultivation unit that uses sunlight as an energy source to hydroponically cultivate rice, A Euglena cultivation unit that uses sugars obtained by decomposing rice harvested from the aforementioned hydroponic cultivation unit to perform heterotrophic cultivation of Euglena in a culture tank, A biodiesel fuel production plant comprising a fuel production unit that produces biodiesel fuel from Euglena cultured in the aforementioned Euglena culture unit.

2. The hydroponic cultivation unit is equipped with a solar lighting system that collects sunlight, A solar panel capable of supplying power to a lighting device installed within the hydroponic cultivation unit, The biodiesel fuel production plant according to claim 1, further comprising a storage battery capable of storing electricity generated by the aforementioned solar panels.

3. The biodiesel fuel production plant according to claim 1 or 2, wherein the Euglena cultivation unit comprises a plurality of culture tanks.

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