JP5815931B2 - Useful substance production system by culturing algae - Google Patents

Description

  In recent years, there are concerns about the increase in atmospheric carbon dioxide concentration, air pollution, and depletion of resources due to the massive use of fossil fuels, and development of alternative energy that can supply energy stably and continuously without relying on fossil fuels. Is an urgent need. As one such alternative energy, the use of biofuel produced from biomass resources has begun. However, since biofuel-producing crops such as rice, wheat, and corn are edible plants, the use of these biomass resources as raw materials for biofuels causes competition with the supply and demand of food, and the supply of food in developing countries. New problems such as these have arisen.

On the other hand, algae has recently attracted attention as a biofuel production system. It has become clear that some algae have a high lipid accumulation capacity, various hydrocarbons, saccharides, and the like, and many characteristics not found in terrestrial biomass. For example,
Botryococcus braunii, Chlorella sp.,
Cryptothecodinium cohnii, Cylidrotheca sp.,
Dunaliella primolecta, Isochrysis sp.,
Monallanthus salina, Nannochloris sp.,
Nannochloropsis sp.,
Neochloris oleoabundans., Nitzschia sp.,
Phaeodactylum tricornutum, Schizochytrium sp.,
Tetraselmis suieia
Produce hydrocarbon substances such as oil inside and outside the cell. When producing biofuel from algae, there is no problem with the above-mentioned edible plants, and the costs of irrigation equipment and fertilization are low, especially marine algae can be grown without using fresh water Moreover, it has the merit that it is possible to use the ocean that occupies 70% of the surface area of the earth, not limited to land.

  Furthermore, when producing biofuel from rice, wheat and corn, the annual production per hectare of cultivated land is 1.6 kL / ha / yr, 0.7 kL / ha / yr and 2.1 kL / ha / yr, respectively. On the other hand, it is known that algae is 11 to 90 kL / ha / yr, which is several tens of times higher than that of conventional raw material species. Based on such a background, research and development of biofuel production by algae is actively conducted in various parts of the world mainly in the United States. In addition, as a biofuel production technique using algae, the following patent document 1 is known.

  In addition to biofuels, some algal species are also known to produce useful physiologically active substances that serve as raw materials for pharmaceuticals and the like. For example, Parachlorella sp. Binos produces alginate-like extracellular secreted polysaccharides, fatty acids, vitamins, and the like. Therefore, in recent years, a lot of researches have been conducted with the focus on the development and use of various materials such as useful materials such as functional foods, pharmaceuticals, domestication, plastics, and pigments by extracting useful substances from algae.

Special table 2010-518850 gazette

  However, for the cultivation of algae that produce useful substances such as hydrocarbons, it is necessary to prevent contamination of other algal species, supply high concentrations of carbon dioxide, supply light, maintain proper water temperature, and nutrients necessary for growth. Production processes such as the addition of fertilizer (fertilization), separation of algae from water, extraction and purification of useful substances from algae are still necessary, and the production cost of biofuel from algae is still high, and most production systems are practical The current situation is that it has not reached the conversion phase.

  The present invention has been made in view of the above points, and the technical problem is that it is possible to perform cultivation of algae and extraction of useful substances such as biofuel from algae at a low cost. Is to provide a secure system.

As a means for effectively solving the technical problem described above, a useful substance production system by culturing algae according to the invention of claim 1 includes a culturing means for algae cultivating useful substance, and algae cultured by the culturing means. Useful from solid-liquid separation means for separating from culture water, first return means for returning culture water separated from algae by this solid-liquid separation means to said culture means, and algae separated by said solid-liquid separation means Useful component extraction means for separating and extracting components, a methane fermentation apparatus for mineralizing or solubilizing the residue after separating and extracting useful components, and the components mineralized or solubilized by the methane fermentation apparatus for culturing the components a second returning means for returning to the unit, provided with nutrients replenishing means for replenishing the decrease of nutrients necessary for cultivation of algae in the culture unit, the methane generated by the methane fermentation The carbon dioxide generated by converting the energy or electric energy is characterized in that the supply to the culture means.

  The algae here is a general term for organisms that perform oxygen-generating photosynthesis, excluding moss plants, fern plants, and seed plants that mainly live on the ground. That is, from eubacteria cyanobacteria (cyanophyceae) to eukaryotes that are unicellular organisms (diatoms, yellow green algae, dinoflagellates, etc.) and multicellular organisms algae (red algae, brown algae, green algae), etc. It is. And the algae targeted in the useful substance production system by culturing algae according to the present invention is a floating algae (phytoplankton) algae having a size of 1 to 1000 μm that inhabit freshwater and seawater, excluding large algae such as seaweed, The type is not limited.

  The useful substance production system by culturing algae according to the invention of claim 2 is characterized in that, in the configuration described in claim 1, high concentration carbon dioxide generated in a thermal power plant or factory is supplied to the culture means. To do.

The useful substance production system by culturing algae according to the invention of claim 3 is characterized in that, in the configuration described in claim 1, the culture means is an open pond water tank or pond.

The useful substance production system by culturing algae according to the invention of claim 4 is the structure described in claim 1, wherein the useful component extraction means for the useful component from the solid part comprises a fuel oil extraction device and a purification device. It is characterized by.

The system for producing useful substances by culturing algae according to the invention of claim 5 is the structure described in claim 1, wherein the energy required for the operation of each means is converted into the fuel oil extraction device described in claim 4 and It is characterized by being covered by part of the biofuel extracted by the refiner.

The system for producing useful substances by culturing algae according to the invention of claim 6 provides that in the configuration described in claim 1, the energy required for the operation of each means is provided by biogas produced by the methane fermentation apparatus. It is a feature.

According to the useful substance production system by culturing algae according to the present invention, nutrient elements necessary for the growth of algae in the culturing means are returned from the solid-liquid separation means to the culturing means via the first return means. Water and the solubilized component returned from the methane fermentation apparatus to the culture means via the second return means are recycled and used, and the water necessary for algae growth is also supplied by the first and second return means. Since it is recycled and only the loss is replenished from the outside, useful substances such as hydrocarbons that can be used as biofuel can be obtained at low cost, and the use of chemicals and the like can be greatly reduced.

In addition, the high concentration of carbon dioxide necessary for the growth of algae can be reduced in this respect by using the one generated from the methane fermentation apparatus in the system or one generated at the thermal power plant or factory. At the same time, it can contribute to the reduction of the amount of carbon dioxide released into the atmosphere.

In addition, the biogas generated by mineralizing the residue after extraction of useful substances from algal cells using a methane fermentation apparatus and a part of the extracted biofuel cover the energy required for the operation of each means. In other words, energy can be saved.

It is schematic structure explanatory drawing which shows the useful substance production system by culture | cultivation of the algae concerning this invention. It is explanatory drawing which shows the culture | cultivation means in the useful substance production system by culture | cultivation of the algae concerning this invention. It is a schematic structure explanatory drawing which shows the precoat-type rotary drum apparatus used as a solid-liquid separation means in the useful substance production system by culture | cultivation of the algae concerning this invention. It is IV-IV sectional drawing in FIG. It is a schematic structure explanatory view showing a preferred example of a useful substance production system by cultivation of algae according to the present invention.

  Hereinafter, a useful substance production system by algae culture according to the present invention will be described with reference to the drawings. First, FIG. 1 is a schematic configuration explanatory diagram of this system.

  In FIG. 1, reference numeral 1 is a culture means for culturing algae, reference numeral 2 is a solid-liquid separation means for separating algae cultured by the culture means 1 from culture water, and reference numeral 3 is a solid-liquid separation means 2. First return means for returning culture water separated from algae to the culture means 1, reference numeral 4 is useful component extraction means for separating and extracting useful components from algae separated by the solid-liquid separation means 2, see Reference numeral 5 is a residue processing means for solubilizing the residue after separating and extracting useful components, and reference numeral 6 is a second means for returning the mineralized or solubilized components to the culture means by the residue processing means 5. The reference numeral 7 is a nutrient component replenishment unit for replenishing the culture unit 1 with a decrease in nutrient components necessary for algae culture.

As the algae to be cultured, for example, as described above, a hydrocarbon-based substance such as oil is produced inside and outside the cell.
Botryococcus braunii, Chlorella sp.,
Cryptothecodinium cohnii, Cylidrotheca sp.,
Dunaliella primolecta, Isochrysis sp.,
Monallanthus salina, Nannochloris sp.,
Nannochloropsis sp.,
Neochloris oleoabundans., Nitzschia sp.,
Phaeodactylum tricornutum, Schizochytrium sp.,
Tetraselmis suieia
However, the type is not particularly limited as long as it is an algae having a size of 1 to 1000 μm inhabiting freshwater and seawater.

  Algae absorb inorganic nutrients, synthesize organic matter and oxygen from carbon dioxide and water by photosynthesis, and grow. For this reason, as the culture means 1, a culture tank or a culture pond filled with culture water is used, and the light supply means 11 and the carbon dioxide supply means 12 are provided.

  FIG. 2 is an explanatory diagram showing culture means in the useful substance production system by culturing algae according to the present invention. The culture means 1 may be a bioreactor system (closed system) or an outdoor system (direct use of the ocean, lakes, and rivers), but since this system is a material circulation system, an open pond system or a bioreactor system can be used. desirable. In the example shown in FIG. 2, an open pond (open system) pond or water tank (hereinafter referred to as a culture tank) 10 is employed as the culture means 1. The culture tank 10 is formed in an endless circulation channel shape, and the culture water W in the culture tank 10 circulates and flows in a certain direction by a water flow generator 13 such as a rotor or an underwater mixer.

  The shape of the open pond culture tank 10 may be similar to that of a reaction tank (aeration tank) in activated sludge for general wastewater treatment, but the water depth is compared so that the algae that has grown are sufficiently exposed to light. It is desirable to be shallow (about 20 cm to 1 m). In the case of a bioreactor system, light can be evenly supplied to algae by cultivation in a transparent tube-type cylinder.

  The nutrient source supplied to the culture tank 10 is composed of nitrogen (N), phosphorus (P), and metal salts that are trace elements, which are necessary in large quantities for the growth of algae. As will be described later, nitrogen, phosphorus and inorganic nutrient sources are residues (algae) after extracting useful substances in the useful component extraction means 4 from algae separated from the culture water by the solid-liquid separation means 2 shown in FIG. Body) is obtained by decomposing and mineralizing or solubilizing in the residue treatment means 5.

  As the light supply means 11 to the culture tank 10, it is conceivable to supply sunlight or artificial light. However, using sunlight which is natural energy contributes to cost reduction and reduction of carbon dioxide in the atmosphere. This is desirable.

As the means 12 for supplying carbon dioxide (CO ₂ ) to the culture water W in the culture tank 10, those supplied from the atmosphere or those supplied from exhaust gas are applicable. In particular, it is possible to supply high-concentration carbon dioxide by using exhaust gas after combustion of a hydrocarbon-based liquid (oil-based) or gas, which can increase the growth rate of algae, and carbon dioxide. Can contribute to reducing emissions. Moreover, when the culture tank 10 is an open pond system, since the culture water W is in contact with the atmosphere, carbon dioxide in the atmosphere is supplied separately from the carbon dioxide in the exhaust gas, which is efficient.

  As a method of supplying carbon dioxide to the culture water W, since the efficiency of the method relying only on dissolution / diffusion from the water surface is poor, air or exhaust gas containing carbon dioxide is contained in the culture water W as shown in FIG. It is desirable that the culture water W is aerated by being discharged by an aeration device (or a fine bubble generation device) 12a installed in the apparatus. According to this method, the bubble of carbon dioxide released into water can also serve as a stirring function for preventing algae from settling. If stirring is insufficient with only the air diffuser (or fine bubble generator) 12a, a mechanical stirrer (not shown) may be used in combination.

  Moreover, when the culture tank 10 is an open pond system, carbon dioxide in the atmosphere can be supplied to the culture water W by using a surface aeration apparatus (not shown) such as a water wheel.

  Depending on the algae, it may be necessary to adjust the temperature of the culture water W by the heating device 14. In this case, a large amount of the culture water W is heated. It is desirable to use the heat source. The heating device 14 shown in FIG. 2 exchanges heat with the culture water W by passing a heat medium (liquid or gas) heated by a heat source through a heat radiating tube 14 a such as a snake tube installed in the culture tank 10. As a heat source, for example, it is conceivable to introduce waste heat from a factory or the like. Moreover, as the heating apparatus 14, the system which supplies and heats the carbon dioxide to the culture water W simultaneously with the high temperature exhaust gas from a factory etc. is also employable.

  As will be described later, since the culture water W containing nutrient components necessary for culturing algae is supplied to the culture tank 10 in a timely manner by the nutrient component supply means 7, an amount of culture water corresponding to the supply amount is provided. It will overflow. Then, the algae cultured in the culture tank 10 are sent to the solid-liquid separation means 2 together with the overflowing culture water, where the algae and the culture water are separated.

  That is, most of the culture water W in the culture tank 10 is composed of water. Therefore, when extracting useful substances produced inside and outside the cells of algae in the culture water W, first, the solid-liquid separation means 2 is used. It is necessary to take out the algae from the culture water W. Solid-liquid separation methods include sedimentation separation method, flotation separation method, and filtration method. Which method is used depends on the characteristics of the algae to be collected. For example, in the case of algae that quickly settle, the sedimentation separation method is selected, and in the case of algae that float on the water surface in a scum shape, the floating separation method may be selected.

  In addition, since most of the algae are phytoplankton suspended in the culture water W, the sedimentation separation method and the flotation separation method cannot be adopted as they are, but flocculants (floats) are added by adding a flocculant. If it is an aggregate of the above, flotation separation or sedimentation separation can be achieved. However, in this case, since some drugs are accumulated in the system, there are concerns about adverse effects on useful substances extracted from algae. Therefore, in such a case, it is conceivable to perform solid-liquid separation by a centrifugal separation method without adding a chemical such as a flocculant. However, since the method using centrifugation has a large power consumption, it may not be profitable depending on the value of the product, and the energy balance may be severe.

  In addition, a general filtration method is a method generally selected when the liquid which does not contain solid content is required, and is unsuitable for collection | recovery of solid content.

  In consideration of these, in the illustrated embodiment, a precoat type rotary drum type solid-liquid separation device 20 as shown in FIGS. 3 and 4 is employed as the solid-liquid separation means 2. That is, FIG. 3 is an explanatory view showing a precoat type rotating drum type solid-liquid separation device suitably used in the useful substance production system by culturing algae according to the present invention, and FIG. is there.

  This precoat type rotary drum type solid-liquid separation device (hereinafter simply referred to as a solid-liquid separation device) 20 is supplied from the culture tank 10 of FIG. 2 and stores a culture water W1 in which algae are mixed in suspension. 21 and the solid-liquid separation drum 22 disposed in the treatment tank 21 and the precoat layer PC formed by adhesion of algae floating in the culture water W1 on the outer peripheral surface of the solid-liquid separation drum 22 are separated and collected. And a recovery means 23.

  That is, the culture water W1 overflowed from the culture tank 10 is supplied to the treatment tank 21 in the solid-liquid separator 20 through the water supply pipe 24 in a state where cultured algae are mixed. The treatment tank 21 in the separation device 20 is provided with a drain port 21b located at the lower portion of the surface facing the solid-liquid separation drum 22 on one side wall 21a.

  The solid-liquid separation drum 22 in the solid-liquid separator 20 is rotated at a low speed around a horizontal virtual axis while being immersed in the culture water W1 in the treatment tank 21, and is shown in FIG. Thus, it has a shape in which one side in the axial direction is opened. The cylindrical outer peripheral wall is made of a mesh 22a such as a wire cloth, and the outer diameter portion on the opened side slides on the inner side surface of one side wall (side wall where the drain port 21b is opened) 21a of the processing tank 21. A drainage storage chamber S is defined between the side wall 21a and the side wall 21a. Reference numeral 22 b is a seal member provided around the opened outer diameter portion of the solid-liquid separation drum 22.

  In FIG. 3, when the solid-liquid separation drum 22 rotates clockwise, the outer peripheral portion (mesh 22a and precoat layer PC) of the solid-liquid separation drum 22 floats from the surface of the culture water W1 on the left side in the figure. Then, immerse below the surface of the culture water W1 on the right side in the figure. And in the upper part of the processing tank 21, the water supply pipe 24 extended from the culture tank 10 in the culture | cultivation means 1 demonstrated previously is located in the drum immersion side, and in this inside of the processing tank 21, this water supply pipe 24 is opened. The culture water W1 supplied into the treatment tank 21 is moved forward in the rotational direction from the position where the outer periphery of the solid-liquid separation drum 22 is submerged below the water surface as it rotates, preferably the lowermost part of the solid-liquid separation drum 22 ( The flow guide member 25 is provided so as to be in contact with the outer periphery of the solid-liquid separation drum 22 for the first time in the forward direction of rotation with respect to the vertical line passing through the axis and to be supplied in the rotational direction (clockwise). It has been. In other words, the flow guide member 25 guides the culture water W1 supplied to the treatment tank 21 to a position unevenly distributed on the drum floating side.

  The recovery means 23 in the solid-liquid separation apparatus 20 has a surface level of the precoat layer PC formed by algae attached to the outer peripheral surface of the mesh 22a of the solid-liquid separation drum 22 from the water surface level L1 of the culture water W1 in the treatment tank 21. The roller 231 for transferring and adhering the precoat layer PC from the mesh 22a of the solid-liquid separation drum 22 by being rotated in the opposite direction to the solid-liquid separation drum 22 while being in contact with the upper side, and the transfer and adhesion to the roller 231 And a scraper 232 that scrapes off the solid matter C made of algae.

  In the solid-liquid separation device 20 configured as described above, the culture water W1 from the culture tank 10 shown in FIG. 2 is supplied together with algae into the treatment tank 21 through the water supply pipe 24. The culture water W1 supplied to the treatment tank 21 is solidified by a water head difference H (= L1-L2) from the filtrate W2 in the filtrate storage chamber S of the solid-liquid separation drum 22 immersed in the culture water W1. The filtered water storage chamber S between the solid-liquid separation drum 22 and the side wall 21a is filtered by the mesh 22a on the outer peripheral wall of the liquid separation drum 22 and the precoat layer PC formed by attaching and depositing floating algae on the outer peripheral surface thereof. It flows in as filtered water W2.

  When the solid-liquid separation drum 22 rotates in the clockwise direction in FIG. 3, the mesh 22a of the solid-liquid separation drum 22 is in a state where the precoat layer PC has been removed by the recovery means 23 above the surface of the culture water W1. Then, on the drum immersion side, the culture water W1 is immersed below the surface of the culture water W1, and from this position, the formation of the precoat layer PC is started by the adhesion and deposition of algae contained in the culture water W1, and the culture water W1 is rotated clockwise. As it moves, the layer thickness of the precoat layer PC increases, rises from the water surface on the drum floating side, and this precoat layer PC is peeled and collected as a solid C by the collecting means 23. Such an operation is repeated continuously.

  The filtrate W2 filtered through the mesh 22a on the outer peripheral wall of the solid-liquid separation drum 22 and the precoat layer PC and flowing into the filtrate storage chamber S contains nutrient elements necessary for algae growth and a part of fine algae. include. The filtrate W2 is returned to the culture means 1 (culture tank 10) from the drain port 21b opened in the treatment tank 21 via the first return means 3 shown in FIG. The first return means 3 is constituted by, for example, a pipe line and a pump.

  Meanwhile, the algae scraped as the solid C from the solid-liquid separation drum 22 by the recovery means 23 in the solid-liquid separation apparatus 20 are separated and extracted by the useful component extraction means 4 by a physical technique or a chemical technique. Is done.

  Here, depending on the algal species, there are species that accumulate useful components in cells, and species that secrete extracellularly as well as intracellularly and accumulate a large amount of secretions in colonies. Therefore, in order to separate useful substances from the collected algae, the method differs depending on whether the existence is intracellular or extracellular. That is, in the case of an algal species having a large amount of extracellular secretion, the cells may be separated without breaking the cells. For example, in algae that produces fats and oils as useful components, the fats and oils can be extracted by processing such as pressing and oil-water separation. In the case of algae accumulating in cells, the cell wall should be destroyed with acid, pulverization, ultrasonic waves, etc., and then the oil and fat should be extracted with an organic solvent such as hexane or acetone to separate the organic solvent from the oil. Purify with. In addition, a technique for extracting oil at low cost by simplifying the process up to extraction using ethanol or dimethyl ether has been developed, and the extract can be methylesterified and used as biodiesel.

  The algal body residue after the useful substance is separated and extracted by the useful component extraction means 4 is mineralized or solubilized by the residue processing means 5.

  Specifically, a large amount of nutrient sources necessary for algae growth remain in the algal body residue after extraction of useful components. Especially in hydrocarbon-based algae, the elements contained in the extract are carbon and hydrogen, and the residue from which they are extracted contains almost all the nitrogen, phosphorus, and metal salts that are essential for the growth of the algae. Yes. However, since many of the nutrient elements contained in the residue are composed of organisms, they cannot be used for algae growth as they are. For this reason, the residue processing means 5 performs the mineralization processing of the extraction residue, or performs the solubilization (low molecular organic conversion) processing so as to easily become mineralized and become a nutrient element in the culture tank 10. The treated water W3 containing nitrogen, phosphorus and metal salt obtained in the residue treatment means 5 is returned to the culture means 1 (culture tank 10) via the second return means 6. The 2nd return means 6 is comprised by a pipe line, a pump, etc., for example.

Combustion or biological treatment can be applied as a mineralization treatment method for organic matter, but the extraction residue is a wet biomass containing a large amount of moisture, so the mineralization method by combustion requires a large amount of oil in the residue. Not suitable except. On the other hand, biological treatment includes a treatment method by aerobic decomposition using aerobic microorganisms and a treatment method by anaerobic decomposition using anaerobic microorganisms. Among these, aerobic decomposition has a high organic matter decomposition rate, but on the other hand, the supply of oxygen is indispensable and the amount of sludge generated is high, so the running cost is high. On the other hand, in the case of anaerobic decomposition, the decomposition rate of organic matter is slower than that of aerobic decomposition and the decomposition rate of organic matter is low, but on the other hand, together with carbon dioxide (CO ₂ ), methane (CH ₄ ) and hydrogen Biofuel such as gas (H ₂ ) is produced, and the amount of sludge produced is small, which is preferable.

  In general, anaerobic decomposition treatment using anaerobic microorganisms is advantageous for high concentration organic wastewater, and aerobic decomposition treatment is advantageous for low concentration organic wastewater. In addition, biogas recovery equipment using anaerobic decomposition treatment has a high initial concentration of equipment because the tank structure is sealed and equipment such as a gas holder is required separately. Running costs will be lower if drainage is used. That is, when the amount of processing is small, the initial value of the anaerobic processing is high, so the aerobic processing is cheaper as the life cycle cost, and when the amount of processing is large, the life cycle cost is cheaper with the anaerobic processing. For this reason, it is necessary to select an anaerobic process or an aerobic process in consideration of these.

  In this way, by returning the treated water W3 mineralized or solubilized (low molecular weight) by biological treatment to the algae culture tank 10, a new supply of a large amount of nutrient sources for culturing algae is greatly increased. It is possible to construct a useful substance production system using low-cost material-circulating algae that can be reduced.

  In addition, biogas produced by anaerobic treatment, such as biogas produced by the methane fermentation method, is composed of 60% methane and 40% carbon dioxide. When converted to electricity, methane is converted to carbon dioxide, and the exhaust gas becomes high-concentration carbon dioxide. Therefore, by using this exhaust gas as a carbon dioxide source necessary for algae growth for aeration of the culture tank 10, a highly efficient system with a high carbon dioxide reduction effect can be realized.

  The nutrient component replenishment means 7 replenishes the culture means 1 (culture tank 10) with a decrease in nutrient components necessary for algae culture. That is, as described above, the nutrient components necessary for the cultivation of algae are inorganic nutrient sources such as nitrogen, phosphorus and metal salts, which are usefully separated and extracted by the useful component extraction means 4. It is inevitable that the material is slightly lost in the treatment process, such as being slightly transferred to the substance, or disappearing (denitrification / sludge) in the process of decomposing the algal body residue in the residue treatment means 5. For this reason, the nutrient component loss is newly replenished from the outside by the nutrient component replenishing means 7. As a replenishment method, supply with chemicals, supply of water rich in nutrient sources such as factory effluent, river water, seawater and the like is possible.

  That is, the useful substance production system according to the present invention returns nutrients such as nitrogen, phosphorus and metal salts that are necessary for algae growth in a large amount, and a solution obtained by decomposing and solubilizing the residue obtained by extracting useful substances from algae. It is characterized by the fact that it is a circulation type that can be supplied by the process, and because it produces useful substances that are raw materials such as biofuel from algae, it does not cause competition with the supply and demand of food and is useful per unit area Since the production amount of the substance is high, a useful substance can be obtained efficiently at low cost.

  FIG. 5 is a schematic configuration explanatory view showing a preferred embodiment in which the useful substance production system by culturing algae according to the present invention is an oil production system using hydrocarbon-based algae.

  The oil-containing algae cultured in the open pond culture tank 10 as shown in FIG. 2 described above overflows from the culture tank 10 by an amount corresponding to the amount of culture water supplied by the nutrient component supply means 7. Along with water, it is sent to the precoat type rotary drum type solid-liquid separator 20 through the water supply pipe 24. The solid-liquid separator 20 divides the oil-containing algae and the culture water (filtered water) W2, and the culture water W2 is returned to the culture tank 10 by a pump 31 serving as a first return means. The oil-containing algae recovered by the recovery means 23 in the solid-liquid separator 20 (in this case, it is assumed that the seeds are secreted outside the cells and form colonies) are compressed into oil and algae by the pressing device 41 that is a useful component extraction means. Divided into residues. The recovered oil is refined by the oil refining device 42 and, for example, as driving energy of a boiler or gas turbine 8 serving as a driving source or heat source of each facility in the system, or conveyed outside the system, and is used for an automobile or a thermal power plant. It can be used as fuel.

On the other hand, the algal residue is sent to a methane fermentation apparatus (biogasification facility) 51 as a residue treatment means, and the organic matter in the residue together with carbon dioxide (CO ₂ ) is methane (CH ₄ ) or hydrogen gas (H ₂ ). Converted into biogas. This biogas can be used as driving energy for the boiler and gas turbine 8 in the system, in other words, can be used as a power source and heat source for the system.

  Digestive fluid (high-concentration wastewater of inorganic elements and low-molecular soluble organic matter), which is a residue of methane fermentation in the methane fermentation apparatus 51, contains inorganic nutrient sources such as nitrogen (N), phosphorus (P) and metal salts at high concentrations. Since it contains, it is returned to the culture tank 10 by the pump 61 which is a 2nd return means. If the sludge generated in the methane fermentation apparatus 51 is soluble, it is sent to the culture tank 10, otherwise it is taken out of the system and incinerated at a thermal power plant or the like, or incinerated in the system. Further, carbon dioxide generated in the boiler, gas turbine 8, thermal power plant, factory, etc. is cultured through a diffuser (or fine bubble generator) 12a which is a carbon dioxide supply means described in FIG. It is supplied to the culture water W in the tank 10.

  According to this embodiment, a part of biogas or refined oil produced in the system is used to convert it into electric energy or heat energy to cover 100% of the power of the system. And what subtracted the self-consumption in the refined oil system is the production amount (supply amount outside the system).

  Therefore, since it is an oil production system based on algae culture using a solar energy-utilizing substance, it is possible to provide a revolutionary system that can produce fuel oil only by supplementing nutrient elements and water that are slightly lost in the system. Can do.

DESCRIPTION OF SYMBOLS 1 Culture | cultivation means 10 Culture tank 11 Light supply means 12 Carbon dioxide supply means 2 Solid-liquid separation means 20 Precoat type rotary drum type solid-liquid separation apparatus 3 First return means 31 Pump 4 Useful component extraction means 41 Squeezing apparatus 5 Residue Material processing means 51 Methane fermentation equipment (biogasification equipment)
6 Second return means 61 Pump 7 Nutritional component supply means

Claims (6)

Means for culturing useful substance-producing algae, solid-liquid separation means for separating algae cultured by this culture means from culture water, and returning culture water separated from algae by this solid-liquid separation means to the culture means One return means, useful component extraction means for separating / extracting useful components from algae separated by the solid-liquid separation means, and a methane fermentation apparatus for mineralizing or solubilizing the residue after separating / extracting useful components And a second returning means for returning the mineralized or solubilized component by the methane fermentation apparatus to the culturing means, and a nutrient component supplying means for supplying a reduced amount of nutrient components necessary for culturing algae in the culturing means. the provided, algae, characterized in that for supplying the carbon dioxide generated by the methane generated by the methane fermentation is converted into heat energy or electric energy to said culture means Useful substance production system by the culture.   The useful substance production system by culturing algae according to claim 1, wherein high concentration carbon dioxide generated in a thermal power plant or factory is supplied to the culture means. The useful substance production system according to claim 1, wherein the culture means is an open pond water tank or pond . 2. The useful substance production system by culturing algae according to claim 1, wherein the means for extracting useful components from the solid portion comprises a fuel oil extraction device and a purification device . The algae culture according to claim 1, wherein the energy required for the operation of each means is covered by a part of the biofuel extracted by the fuel oil extraction device and the purification device according to claim 4. By useful substance production system. The useful substance production system by culturing algae according to claim 1, wherein the energy required for the operation of each means is covered with biogas produced by a methane fermentation apparatus .

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