JP6081733B2 - Oil production method and production system from microorganism capable of producing hydrocarbon - Google Patents

Description

  The present invention relates to a method for producing oil from a microorganism capable of producing hydrocarbons, and a production system.

  Biofuels are expected to replace petroleum fuels and are being developed and researched. For example, Patent Document 1 discloses, as a method for producing hydrocarbons, a heat treatment step in which an aqueous slurry of hydrocarbon-producing microorganisms is heated and maintained at a temperature of 45 ° C. or higher and lower than 150 ° C. And a recovery step of recovering an oily substance containing hydrocarbons produced by a productive microorganism. Patent Document 2 discloses a decomposition apparatus for decomposing organisms, a culture apparatus for culturing heterotrophic algae using the decomposed microorganism as a nutrient source, and an extraction apparatus for extracting fats and oils from heterotrophic algae. An oil and fat manufacturing system is disclosed.

JP 2010-111865 A JP 2010-246407 A

  Biofuel production began with the recovery of biodiesel oil from waste cooking oil, animal fats and oils. Terrestrial plants require a lot of water resources and vast cultivated land, but they can increase oil extraction efficiency because they accumulate oil in their seeds, but they have a competitive relationship as a raw material for food, feed and fuel. As a result, fuel production has begun to decline. On the other hand, bioethanol using a fermentation operation using waste wood and pulp as a starting material has been recognized as a fuel. On the other hand, attempts are being made today to use microalgae, which can be cultivated even in a small amount of water resources and wasteland, and are fast growing.

  The oil-producing ability per unit area of microalgae is higher than that of land plants. Among microalgae that inhabit freshwater, for example, Botryococcus brownies have a particularly high oil content per dry weight. Botryococcus brownie is also known as the only microalgae that releases oil extracellularly. Therefore, it has been verified that Botryococcus brownie produces hydrocarbon oil directly as Drop-in Fuel that can be used as fuel without purification.

However, as for microalgae, the actual situation is that the integrated oil production technology has not yet been established. In particular, there are many technical problems in each unit operation of the manufacturing process from harvesting of cultured algae to dehydration / concentration and oil extraction. For example, in the process of concentrating and harvesting microalgae (from harvesting of cultured algae to dehydrating and concentrating), conventionally, a technique of centrifuging microalgae cultured in a medium using a centrifuge has been employed. The density at the time of harvesting of microalgae is, for example, about 0.5 kg / m ³ (99.5% water content), and an ultracentrifuge that rotates faster than the centrifuge has been used on a laboratory scale. In industrial applications, the same centrifugal solid-liquid separator and screw decanter are used mechanically for the purpose of extracting high value-added materials and the like. In order to centrifuge the whole culture medium containing dilute microalgae, a very large power has been conventionally required. In addition, since most of the oil produced by microalgae is in the cells, a process for destroying the cells (cell walls and cell membranes) and extracting the cells containing oil out of the cells is necessary in order to increase the extraction efficiency. . Regarding the destruction of cell walls and cell membranes, for example, a French press is used on a laboratory scale, and destruction is performed by applying a stress of about 300 atm. However, in practice, enormous power is required for cell destruction. On the other hand, a device on a test scale has been developed that demonstrates both water absorption and oil extraction using DME (dimethyl ether), which dissolves both water and oil polar substances. However, because of the physical properties, the amount of liquefied DME necessary for water absorption needs to be about 10 times the amount of water absorption, so that a large amount of DME needs to be stored. Explosion-proof measures associated with the handling of flammable gas and liquid phases, procedures such as certification of high-pressure gas handling stations, etc. are the biggest barriers to equipment scale expansion and equipment operation.

  In view of the above problems, an object of the present invention is to provide a technique for producing oil from microorganisms capable of producing hydrocarbons with low energy consumption.

  In order to solve the above-mentioned problems, the present invention dehydrates and concentrates microalgae, and slowly freezes the cells of the concentrated microalgae by maintaining them in a predetermined freezing temperature zone where the cells are supercooled for a predetermined time. And cell membrane).

  Specifically, the present invention is a method for producing oil from a microorganism capable of producing hydrocarbons, a culture step of culturing the microorganism in a medium, and dehydrating a microorganism containing the medium cultured in the culture step. A concentration step for concentrating the cells, a cell destruction step for destroying the cells of the microorganisms by slow refrigeration maintained for a predetermined time in a predetermined freezing temperature zone where the cells of the microorganisms concentrated in the concentration step are supercooled, and the cells An oil separation and recovery step of separating and recovering oil from the microorganisms destroyed in the destruction step.

  The microorganism capable of producing hydrocarbons may be any microorganism that produces hydrocarbons by photosynthesis. Microalgae are exemplified as microorganisms capable of producing microbial hydrocarbons. Examples of microalgae include Botryococcus brownies and Aurantiochytrium. According to the present invention, in the cell destruction step, slow freezing is performed, water is first frozen due to the difference in freezing point of water, cytoplasm, medium, etc. contained in the microorganism, then, the water containing the medium is frozen, The microbial cytoplasm freezes at the end. On the other hand, oil in microorganisms does not freeze. The cell membrane with low water permeability does not sufficiently transfer water due to freezing, and ice is formed inside and outside the cell due to the presence of the cell membrane. As a result, the coarse ice crystals formed in the cells cause cell deposition and expansion, and the cells (cell walls and cell membranes) are also destroyed. This makes it possible to efficiently extract the oil produced inside the cell by photosynthesis during the logarithmic growth phase. As a freezing method different from slow freezing, quick freezing is known in which a cell is passed through a freezing temperature zone in which cells are supercooled in as short a time as possible and maintained at a temperature of, for example, -20 ° C to -30 ° C. In the quick freezing, the ice in the cell grows larger than the quick freezing. Therefore, oil can be separated from microorganisms more efficiently. In the present invention, since it is not necessary to use a French press, for example, as in the prior art, energy consumption when separating oil from microorganisms can be suppressed. Further, by performing the concentration step before the cell destruction step and sufficiently dehydrating the microorganisms, it is possible to further reduce the refrigeration load in the slow freezing.

  Here, in the concentration step, the microorganism may be dehydrated by heating under reduced pressure. It can dehydrate more efficiently by heating in a state where the pressure is lower than the normal pressure. As a result, the refrigeration load in slow refrigeration can be further reduced.

  The concentration step includes a primary concentration step of pressure-filtering and dehydrating microorganisms containing the medium, and a secondary concentration step of heating and dehydrating microorganisms including the medium dehydrated in the primary concentration step under reduced pressure. May be included. By performing dehydration / concentration step by step in this way, the moisture content of the microorganisms containing the medium can be efficiently reduced.

In the cell destruction step, slow freezing may be performed while maintaining at a freezing temperature range of −2 ° C. to −5 ° C. for at least 2 hours. Although the conditions of the cell destruction step are not limited to the above, for example, cell walls and cell membranes of microorganisms can be more effectively destroyed by slow freezing under the above conditions.

  In the primary concentration step, the moisture content of the microorganisms containing the medium may be dehydrated to 70%, and in the secondary concentration step, the moisture content of the microorganisms containing the medium may be further dehydrated to 40%. By dehydrating stepwise as described above, the water content of the microorganisms containing the medium can be efficiently reduced. The moisture content is not limited to the above.

  Here, the present invention can be specified as a system for producing oil from microorganisms capable of producing hydrocarbons. For example, the present invention relates to a production system for producing oil from a microorganism capable of producing hydrocarbons, a culture means for culturing the microorganism in a medium, and a microorganism containing the medium cultured in the culture means. Concentration means for concentrating the cells, cell destruction means for destroying the cells of the microorganisms by slow refrigeration for maintaining for a predetermined time in a predetermined freezing temperature zone where the microorganism cells concentrated by the concentration means are supercooled, and the cell destruction Oil separation and recovery means for separating and recovering oil from microorganisms destroyed by the means.

  According to the present invention, slow freezing is performed by the cell destruction means, oil in the microorganism is not frozen, and ice formation inside and outside the cell due to a decrease in water permeability of the cell membrane of the microorganism is induced. By forming ice inside and outside the microorganism cell, the cell wall and cell membrane can be destroyed, and the oil produced inside the cell by photosynthesis during the logarithmic growth phase can be extracted outside the cell. As described above, in the slow freezing, the ice in the cell grows larger than in the quick freezing. Therefore, oil can be separated from microorganisms more efficiently. In the present invention, since it is not necessary to use a French press, for example, as in the prior art, energy consumption when separating oil from microorganisms can be suppressed. In addition, since the microorganisms sufficiently dehydrated by the concentration means are supplied to the cell destruction means, the refrigeration load in the slow freezing can be further reduced.

  Here, the concentration means may dehydrate the microorganisms by heating them under reduced pressure. It can dehydrate more efficiently by heating in a state where the pressure is lower than the normal pressure. As a result, the refrigeration load in slow refrigeration can be further reduced.

  In addition, the concentration means includes a primary concentration means for dehydrating the microorganisms containing the medium by pressure filtration, and a secondary concentration means for heating and dewatering the microorganisms containing the medium dehydrated by the primary concentration means under reduced pressure. It is good also as a structure containing these. By performing dehydration / concentration step by step in this way, the moisture content of the microorganisms containing the medium can be efficiently reduced.

  Further, the cell disruption means may be slowly frozen by maintaining at a freezing temperature range of −2 ° C. to −5 ° C. for at least 2 hours. By slow freezing under the above conditions, the cell wall and cell membrane of the microorganism can be more effectively destroyed.

  Further, the primary concentration means may dehydrate the moisture content of the microorganisms including the medium to 70%, and the secondary concentration means may further dehydrate the moisture content of the microorganisms including the medium to 40%. By dehydrating stepwise as described above, the water content of the microorganisms containing the medium can be efficiently reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which manufactures oil from the microorganisms which can produce a hydrocarbon with little energy consumption can be provided.

The process for producing oil derived from microalgae according to the embodiment is shown. An example of the oil production system derived from micro algae is shown. An example of the photoculture apparatus in an oil manufacturing system is shown. An example of structures other than the photoculturing apparatus in an oil manufacturing system is shown. An example of the temperature drop pattern by quick freezing and slow freezing is shown. The other example of structures other than the photoculture apparatus in an oil manufacturing system is shown.

  Next, as an example of an embodiment of the present invention, a case where oil is produced from microalgae that are examples of microorganisms capable of producing hydrocarbons will be described with reference to the drawings. The embodiment described below is merely an example, and the present invention is not limited to the embodiment described below.

<Oil production method>
FIG. 1 shows an oil production process derived from microalgae (hereinafter also simply referred to as an oil production process) according to an embodiment. The oil production process according to the embodiment includes a photoculture process (S01), a primary concentration process (S02), a secondary concentration process (S03), a cell disruption process (S04), and an oil separation process (S05). Through these steps, hydrocarbon oil is extracted (produced) from microalgae.

  In this embodiment, microalgae are used as microorganisms capable of producing hydrocarbons, but microorganisms capable of producing hydrocarbons may be microorganisms that produce hydrocarbons by photosynthesis. Examples of microalgae include Botryococcus brownies, aurantiochytrium, chlorella, cyanobacteria, spirulina, aoko.

  In the light culture step (S01), microalgae are cultured. Specifically, light is irradiated in a state where a microalgae strain is dispersed in a medium (culture solution). The type of the culture solution, the light irradiation time, the temperature during the culture and the state of the atmosphere are appropriately set depending on the type of microalgae. When light is irradiated, microalgae photosynthesize and produce hydrocarbons. The produced hydrocarbon accumulates in the cells of microalgae. Moreover, when microalgae gather and form a colony, hydrocarbon accumulates in the space between cells of the microalgae forming the colony. When the photoculture process is completed, the process proceeds to the primary concentration process (S02).

  In the primary concentration step (S02), microalgae containing the medium are pressure filtered, dehydrated and concentrated. In the primary concentration step, for example, the water content of the microalgae including the medium is dehydrated and concentrated to 70%. The filtrate discharged in the primary concentration step can be collected and used in the photoculture step. When the primary concentration step ends, the process proceeds to the secondary concentration step (S03).

  In the secondary concentration step (S03), the microalgae dehydrated and concentrated in the primary concentration step is heated and dehydrated under reduced pressure. In the secondary concentration step, for example, the water content of the microalgae containing the medium is further dehydrated and concentrated to 40%. The filtrate discharged in the secondary concentration step can be collected and used in the photoculture step. By performing the primary concentration step and the secondary concentration step, and dehydrating and concentrating the microalga including the culture medium step by step, the water content of the microalga including the culture medium can be efficiently reduced. In addition, by performing the primary concentration step and the secondary concentration step, it is possible to further reduce the refrigeration load in the slow freezing performed in the cell destruction step as the next step. When the secondary concentration step ends, the process proceeds to the cell destruction step (S04).

In the cell destruction step (S04), the microalgae dehydrated and concentrated in the secondary concentration step are slowly frozen and the microalgae cells (cell walls and cell membranes) are destroyed. Slow freezing is performed, for example, by maintaining microalgae in a freezing temperature range of −2 ° C. to −5 ° C. for at least 2 hours. Thereby, the oil produced by the microalgae by performing the photoculturing step can be extracted outside the cell by destroying the cell wall and the cell membrane. When the cell destruction step is completed, the process proceeds to the oil separation step (S05).

  In the oil separation step (S05), oil is separated and recovered from the microalgae destroyed in the cell destruction step. For example, the oil can be separated and recovered from the mixture of the oil, the medium, and the cells by a gravity separation operation using the difference in coagulation temperature and density of microalgae containing the medium. Through the steps described above, hydrocarbon oil is extracted (produced) from microalgae.

<Oil production system>
Next, the apparatus which can be used with the oil manufacturing method mentioned above is demonstrated. FIG. 2 shows an example of an oil production system for producing oil from microalgae (hereinafter also simply referred to as an oil production system). An oil production system 10 shown in FIG. 2 includes an optical culture apparatus 1 for cultivating microalgae, a primary concentration apparatus 2 for pressure-filtering and dehydrating microalgae containing a medium, and a microalgae including a medium dehydrated by the primary concentration apparatus. A secondary concentrating device 3 for heating and dehydrating under reduced pressure, a cell disrupting device 4 for slowly freezing concentrated microalgae to destroy cells, and an oil separating device 5 for separating and recovering oil from the destroyed microorganisms .

  FIG. 3 shows an example of a light culture apparatus in the oil production system. The photoculture device 1 shown in FIG. 3 is an example of the culture means of the present invention, and can be used for the above-described photoculture step (S01). The photo-cultivating apparatus 1 shown in FIG. 3 is a photo-culturing tank for culturing microalgae, a carbon dioxide source for storing carbon dioxide and supplying it to the photo-cultivating tank, a medium is sterilized and stored, and the sterilized medium is stored in a medium adjustment tank Medium sterilization tank to supply to, medium adjustment tank to store culture medium and supply to light culture tank, cultured storage layer for storing microalgae containing culture medium, medium added to cultured microalgae and fine Includes a tube-type fed-batch photoculture tank for culturing algae.

  In the medium sterilization tank, the medium collected by the primary concentration device 2 and the secondary concentration device 3 can be used. The tube-type fed-batch photocultivation tank is connected to a tube through which microalgae containing the medium flows so that microalgae containing the medium circulate, and the tube is provided with a pump for circulating the microalgae containing the medium. . Further, in the example shown in FIG. 3, four layers of tube type fed-batch photocultivation tanks are provided. The number of tube-type fed-batch photoculture tanks installed is merely an example, and is not limited thereto. Each tank is provided with a thermometer (T), an absorptiometer (OD), an electric conductivity meter (EC), and a dissolved oxygen meter (DO) as measuring instruments, and supplied to a tube-type fed-batch photoculture tank. The supply amount of cultured microalgae, the supply amount of the added medium, the amount and time of light to be irradiated, the supply amount of carbon dioxide, the state of the atmosphere (temperature, etc.) are appropriately adjusted. The microalgae cultured in the tube-type fed-batch photoculture tank is supplied to the primary concentration device 2. In addition, the arrow of FIG. 3 shows the flow of a carbon dioxide, a culture medium, and a micro algae. Each tank shown with the arrow of FIG. 3 or a carbon dioxide source and each tank can be connected by piping. Note that the photoculture system shown in FIG. 3 is an example, and known techniques can be appropriately used for culturing microalgae.

  FIG. 4 shows an example of the configuration of the oil production system other than the photoculture device. The primary concentration apparatus 2 corresponds to the primary concentration means of the present invention, and is constituted by a filter press. The primary concentration apparatus 2 can be used in the primary concentration step described above. The secondary concentrating device 3 corresponds to the secondary concentrating means of the present invention, and is constituted by a vacuum type low temperature heating concentrating device. The secondary concentration apparatus 3 can be used in the secondary concentration step described above. The cell disruption device 4 corresponds to the cell disruption means of the present invention, and is constituted by a slow freezing device. The cell disruption device 4 can be used in the above-described cell disruption step. The oil separation device 5 corresponds to the oil separation and recovery means of the present invention, and is constituted by a separation tank. The oil separation device 5 can be used in the oil separation step described above.

  The filter press is provided with a submerged MF (Micro-filter) flat membrane that requires only the power of the air compressor for cleaning the membrane. The submerged MF flat membrane and the filter press allow microalgae containing the medium to be contained. Is dehydrated and concentrated. The filter press is connected to the photoculture device 1 by piping (not shown in FIG. 4). The piping connecting the filter press and the photoculture device 1 is provided with an electromagnetic valve, and the amount of microalgae including the medium supplied to the filter press can be adjusted by adjusting the opening.

The treatment amount of the submerged MF flat membrane is a parameter that determines the concentration rate, and can be set as appropriate. Here, for example, the range of the treatment amount in the sludge treatment technology field is 5 to 15 kg / m ³ , and the average colony diameter is cultivated as a single species of microalgae having a class of 30 to 50 μm, so that the submerged MF suitable for microalgae is used. The target throughput of the flat membrane can be 20 kg / m ³ as a value larger than sludge. The flux is a parameter that determines the required area of the MF membrane. For example, in the sludge treatment technology field, 0.50 m ³ / m ² / day is applied. Therefore, the flux of the submerged MF membrane can be set to 0.75 m ³ / m ² / day as a larger value than the sludge. On the other hand, the filtration flux of the filter press is a parameter that determines the required area of the filter from the processing speed. For example, 0.5 to 1.0 kg / m ² · h is applied in the sludge treatment technology field. Therefore, the flux can be set to, for example, 0.75 kg / m ² · h. In this way, in the primary concentration process and the secondary concentration process of microalgae, for example, the apparatus may be designed using parameters suitable for one kind of microalgae based on the rule of thumb in the sludge treatment field. .

  The decompression type low temperature heating and concentrating apparatus shown in FIG. 4 has a configuration including a heating tank, a condenser, a venturi tube, and a heat pump type blownler (condenser, evaporator, caprary, compressor). The heating tank is connected to a filter press and contains microalgae containing a medium having a moisture content of 70%. The heating tank is provided with a heating device and can heat microalgae including the culture medium accommodated in the heating tank. The heating device for heating the heating tank and the condenser of the branchler are connected by a pipe through which a heat medium (for example, hot water) flows, and the heating medium supplied from the condenser of the branchler is used for heating the heating tank. Is used. The piping through which the heat medium flows is provided with a pump, and the supply amount of the heat medium supplied to the heating device can be adjusted. When the microalgae containing the culture medium in the heating tank is heated, water vapor is generated, and the generated water vapor mainly accumulates at the top of the heating tank.

  The condenser is connected to a lower water tank provided below the heating tank and the venturi pipe by respective pipes. Water vapor collected at the top of the heating tank is guided to the condenser, cooled by a cooling device that cools the condenser, condensed into water, and stored in the lower water tank. A cooling device for cooling the condenser and an evaporator are connected via a pipe, and a refrigerant discharged from the evaporator (for example, cooling water) is used for cooling the condenser. The piping connected to the evaporator is provided with a pump, and the supply amount of the refrigerant supplied to the cooling device for cooling the condenser can be adjusted.

  The lower water tank stores water supplied via the condenser. The lower water tank is provided with a borer weir and has a two-tank structure. Specifically, the upstream tank stores the drainage water from the condenser and the air from the venturi pipe, and the downstream tank crosses the mooring weir and stores the hydrostatic water. The Venturi tube is supplied with water stored in a downstream tank with suppressed water surface disturbance.

The venturi tube is connected to the heating tank and depressurizes the heating tank. Specifically, a venturi pipe and a downstream tank are connected via a pipe, and a pump is provided in this pipe, and water stored in the downstream tank is pumped up as a working fluid of the venturi pipe. When water as a working fluid passes through the contracted flow portion of the venturi pipe at a high speed, the air in the heating tank is drawn and the inside of the heating tank is depressurized. The pressure tank is provided with a pressure gauge (P), and the pressure of the venturi pump can be adjusted based on the pressure measured by the pressure gauge. By heating and depressurizing the heating tank, the microalgae containing the medium accommodated in the heating tank is dehydrated and concentrated to a moisture content of 40%.

  The slow speed freezing apparatus is a semi-batch type slow speed freezing apparatus connected in series to a heating tank, and contains microalgae containing a medium having a moisture content of 70% and is slowly frozen. A cooling device for cooling the microalgae accommodated in the slow refrigeration apparatus and the evaporator are connected via a pipe, and the refrigerant discharged from the evaporator is used for cooling the slow refrigeration apparatus. . The piping connected to the evaporator is provided with a pump, and the supply amount of the refrigerant supplied to the cooling device for cooling the slow refrigeration device can be adjusted. The slow-speed refrigeration apparatus is provided with a thermometer (T), and the pressure of the pump of the pipe connected to the evaporator can be adjusted based on the temperature measured by the thermometer. Also, a pipe connecting the heating tank and the slow refrigeration apparatus is provided with a discharge valve, and the supply amount of microalgae including the medium supplied to the slow refrigeration apparatus can be adjusted. Also, a discharge valve is provided in a pipe connecting the slow-speed refrigeration apparatus and the separation tank, and the supply amount of microalgae including the medium supplied to the separation tank can be adjusted.

  In the slow freezing apparatus, the microalgae containing the contained medium is maintained at a temperature range of −2 ° C. to −5 ° C. for at least 2 hours. The temperature and time of slow freezing is different from that for quick freezing.Experiments for confirming that intracellular ice can grow larger and that cell walls and cell membranes of microalgae can be more effectively destroyed Experiments can be conducted and determined based on experimental data.

Here, FIG. 5 shows an example of the temperature drop pattern by quick freezing and slow freezing. FIG. 5 shows a temperature drop pattern when Botryococcus brownies are rapidly frozen and slowly frozen as microalgae. From FIG. 5, it can be confirmed that the maximum ice crystal growth temperature range in which growing ice in the cells grows is −2 ° C. to −5 ° C., and the elapsed time of freezing is at least 2 hours, compared to quick freezing . “Fast freezing” is, for example, a method conventionally practiced in the field of frozen food storage and frozen food manufacturing, and “rapid freezing” finely disperses ice that grows by freezing of cells in cells. . “Quick freeze” maintains the food temperature from −20 ° C. to −30 ° C. by passing the freezing temperature zone of −5 ° C. where the cells are supercooled as quickly as possible. On the other hand, “slow freezing” is a method in which ice in growing cells grows greatly by maintaining the temperature of the object in a freezing temperature range of −2 ° C. to −5 ° C. This is what was supposed to be. In the present embodiment, at least 2 microalgae in the range of −2 ° C. to −5 ° C. are used by using a heat pump type branchler whose heat output is 2 (coefficient of performance: 2) with respect to input power in the utilization temperature range. By maintaining the time, the cell wall and cell membrane of Botryococcus brownie are destroyed. By destroying the cell wall and cell membrane, it is possible to roughly separate the oil content extracted from the cell and the water containing the cells and the medium at the coagulation temperature. That is, in the slow freezing apparatus, in addition to the destruction of the cell walls and cell membranes of microalgae, it is possible to roughly separate the oil, the water containing the cells and the medium.

  The separation tank separates and recovers the oil roughly separated by the slow refrigeration apparatus using gravity separation using the solidification temperature difference and density difference.

<Effect>
According to the oil production method and the oil production system according to the embodiment, slow freezing is performed in the cell destruction step, and water is first frozen due to differences in freezing points of water, cells, culture medium, etc. contained in the microalgae, Next, impurities such as culture medium freeze, and microalgae cells finally freeze. On the other hand, oil in microalgae does not freeze. By freezing the cells of the microalgae, the cell wall and cell membrane of the microalgae can be destroyed, and the oil produced by the microalgae in the cells by photosynthesis can be extracted outside the cells. In slow-freezing, the ice in the cells grows larger than in quick-freezing. Therefore, oil can be separated from microorganisms more efficiently. In the oil manufacturing method according to the embodiment, since it is not necessary to use a French press, for example, as in the past, it is possible to suppress energy consumption when separating oil from microalgae. Further, by performing the primary concentration step and the secondary concentration step in steps before performing the cell destruction step and sufficiently dehydrating the microalgae, the freezing load in the slow freezing can be further reduced.

  When producing oil from microalgae, an increase in energy consumption in the cell concentration step and the secondary concentration step, which is the step immediately before, is a particular problem. However, according to the above-described embodiment, the load of slow freezing can be reduced by performing dehydration and concentration not only in the cell destruction step but also in the secondary concentration immediately before that. Evaporation of moisture is promoted under reduced pressure by using a heat pump type bronchiler having high efficiency heat production ability as a heating source and using a pressure reducing action of a Venturi tube using condensed water as a working fluid. Moreover, since the heat of vaporization is taken away by evaporation of water, the temperature of the microalgae is maintained near room temperature. Since the water vapor is condensed in the condenser and discharged as distilled water, this is pumped up as a working fluid for the venturi pipe and decompressed. By utilizing both the cold and hot exhaust heat of the branchler, highly efficient concentrating operation and slow refrigeration operation are realized.

<Industrial applicability>
For example, after 2030, when 20 years have passed since the oil peak, fossil fuel prices are expected to increase from today's 121 $ / B to 240 $ / B due to further economic development in emerging countries. On the other hand, if the exchange rate against the US dollar recovers from the current 80 yen / $ level to the 100 yen / $ level, the refinery shipment price will rise from today's 70 yen / L class to 160 yen / L class. That is expected. During this period, research on microalgae has progressed and it is expected that the Southeast Asian region will be recognized as an industry that creates cheap unit prices of electricity and demand for nighttime electricity. The unit price of oil production from microalgae is expected to be 40 yen / L.

In Japan, oil derived from microalgae has been recognized and entered into the diffusion period after the verification of safety and fuel efficiency as an alternative fuel has been completed in the transportation sector. Due to such changes in the socio-economic environment, oil derived from microalgae is expected to prevail in the transportation and industrial sectors, starting at 40 yen / L, which is overwhelmingly cheaper than fossil fuels. The The current primary energy consumption in terms of oil is 500 million tons / year, 24% in the transport sector (of which 95%
Is fossil fuel), and the industrial sector consumes 43% (of which 60% is fossil fuel). In addition, energy consumption is almost proportional to GDP, and GDP is proportional to population. Therefore, even if GDP is maintained, energy consumption is expected to decrease to 90% due to population decline. Even if electric vehicles are expected to spread during this period, it is expected that a 20% fossil fuel replacement market will be created in the transport and industrial sectors. Therefore, the market size is expected to be 49 million tons / year in terms of oil-converted primary energy. Microalgae absorb carbon dioxide that is 1,000 to 3,000 times the amount of energy required for production and produce oil through photosynthesis, so the carbon neutral effect is very high among greenhouse gases. Carbon emission credits are also expected to be obtained from the United Nations.

<Modification>
In the above-described embodiment, the primary concentration step and the secondary concentration step are performed in order to dehydrate and concentrate the microalgae including the culture medium. However, in a modified example, only dehydration and concentration by a filter press is performed.

FIG. 6 shows another example of the configuration of the oil production system other than the photoculture device. In the example shown in FIG. 6, two slow refrigeration devices as the cell disruption device 4 are arranged in parallel downstream of the filter press as the primary concentration device 2. The filter press is provided with a submerged MF (Micro-filter) flat membrane that requires only the power of the air compressor for cleaning the membrane. The submerged MF flat membrane and the filter press allow microalgae containing the medium to be contained. Is dehydrated and concentrated. Each slow-speed refrigeration apparatus is provided with a cooling device that uses a refrigerant (for example, cooling water) of −15 ° C. or lower from an evaporator of a heat pump type blownler as a heat source for refrigeration. Slow freezing of algae is possible. Further, in the vicinity of the upstream of the slow freezing tank, there is an electromagnetic valve for controlling the amount of microalgae containing the medium supplied to the slow freezing tank, and a moisture meter (M ) Is provided. In addition, the temperature of the heat medium (for example, warm water) from the condenser of a heat pump type branchler is 32 degreeC, for example. A pipe is connected to each of the evaporator and the condenser, and a thermometer (T) is provided in each pipe. The slow refrigeration apparatus is also provided with a thermometer (T), and the slow refrigeration temperature can be adjusted by appropriately adjusting the temperature of the refrigerant.

  In the example shown in FIG. 6, a filter press is provided on the downstream side of the slow refrigeration apparatus, and the microalgae further dehydrated and concentrated by the filter press is separated in a separation tank as the oil separation apparatus 5. The pipe through which the hydrocarbons discharged from the separation tank flow is provided with a density meter that measures the density of the discharged hydrocarbons. A pipe connecting the slow speed refrigeration apparatus and the filter press is provided with a discharge valve, and the supply amount of microalgae supplied to the filter press on the downstream side of the slow speed refrigeration apparatus can be adjusted.

  Also in the modified example shown in FIG. 6, oil can be separated from the microalgae by slowly freezing the microalgae and destroying the cell walls and cell membranes of the microalgae. Since it is not necessary to use, for example, a French press as in the prior art, it is possible to suppress energy consumption when separating oil from microalgae. In addition, by performing dehydration and concentration before the cell destruction step and dehydrating microalgae, it is possible to reduce the refrigeration load in slow freezing.

  The preferred embodiments of the present invention have been described above, but the method for producing oil from microorganisms capable of producing hydrocarbons and the system for producing oil from microorganisms capable of producing hydrocarbons according to the present invention are not limited thereto. These combinations can be included as much as possible.

DESCRIPTION OF SYMBOLS 1 ... Photoculture apparatus 2 ... Primary concentration apparatus 3 ... Secondary concentration apparatus 4 ... Cell destruction apparatus 5 ... Oil separation apparatus 6 ... Oil manufacturing system

Claims (12)

A method for producing oil from microorganisms capable of producing hydrocarbons,
A cell destruction step of destroying the cells of the microorganism by slow freezing to maintain a predetermined freezing temperature range in which the cells of the microorganism are supercooled for a predetermined time;
An oil separation process for separating and recovering oil from microorganisms destroyed in the cell destruction process using a solidification temperature difference between the microorganism and oil, and a method for producing oil from microorganisms capable of producing hydrocarbons .   A culture step of culturing the microorganism in a medium;
  A concentration step of dehydrating and concentrating the microorganisms containing the medium cultured in the culture step,
  The method for producing oil from microorganisms capable of producing hydrocarbons according to claim 1, wherein the cell destruction step destroys the cells of the microorganisms concentrated in the concentration step. The method for producing oil from microorganisms capable of producing hydrocarbons according to claim 2 , wherein in the concentration step, the microorganisms are heated and dehydrated under reduced pressure. The concentration step includes a primary concentration step of pressure-filtering and dehydrating microorganisms containing the medium, and a secondary concentration step of heating and dehydrating microorganisms containing the medium dehydrated in the primary concentration step under reduced pressure. The manufacturing method of the oil from the microorganisms which can produce the hydrocarbon of Claim 2 or 3 containing. In the cell disruption step, to slow freezing and maintained for at least 2 hours at freezing temperature zone of -5 ° C. from -2 ° C., from the production microorganism capable of hydrocarbons according to any one of claims 1 4 Oil production method. Wherein the primary concentration step, the water content of the microorganism containing the medium was dewatered to 70%, the secondary concentration step, further dehydrating the moisture content of microorganisms, including the media up to 40%, according to claim 4 A method for producing oil from microorganisms capable of producing hydrocarbons. A production system for producing oil from microorganisms capable of producing hydrocarbons,
Cell destruction means for destroying the cells of the microorganisms by slow freezing that is maintained for a predetermined time in a predetermined freezing temperature zone where the cells of the microorganisms are supercooled,
An oil production system from microorganisms capable of producing hydrocarbons, comprising: oil separation and recovery means for separating and recovering oil from microorganisms destroyed by said cell destruction means using a difference in coagulation temperature between said microorganisms and oil .   A culture means for culturing the microorganism in a medium;
  A concentration means for dehydrating and concentrating the microorganisms containing the medium cultured by the culture means,
  8. The system for producing oil from microorganisms capable of producing hydrocarbons according to claim 7, wherein the cell destruction means destroys the cells of the microorganisms concentrated by the concentration means. 9. The system for producing oil from microorganisms capable of producing hydrocarbons according to claim 8 , wherein the concentration means dehydrates the microorganisms by heating under reduced pressure. The concentration means includes a primary concentration means for dehydrating the medium-containing microorganism by pressure filtration, and a secondary concentration means for heating and dewatering the microorganism-containing medium dehydrated by the primary concentration means under reduced pressure. A system for producing oil from a microorganism capable of producing a hydrocarbon according to claim 8 or 9 . The microorganism for producing a hydrocarbon according to any one of claims 7 to 10 , wherein the cell disruption means is slow-frozen while maintaining at a freezing temperature range of -2 ° C to -5 ° C for at least 2 hours. Oil manufacturing system. Said primary concentrating means, the water content of the microorganism containing the medium was dewatered to 70%, said secondary concentrating means further dehydrating the moisture content of microorganisms, including the media up to 40%, according to claim 10 A system for producing oil from microorganisms capable of producing hydrocarbons.

Images