Algae reef and manufacturing method thereof

Abstract

The algal reef contains: ash powder obtained by burning coal or biomass; and a curing agent which chemically reacts with the ash powder and is cured in a state in which the ash powder and the curing agent are mixed together. The curing agent may include at least one of slaked lime and semi-hydrated gypsum. The algal reef may contain, as an aggregate, at least one of a granular material containing calcium carbonate and grit. The calcium carbonate-containing granules may also be produced by reacting calcium hydroxide with carbon dioxide in a carbon dioxide absorption device. In the algal reef, the powder containing the ash and the particles of the curing agent can also be contained in a bag through which the liquid can pass.

Description

Technical Field

[0001] The invention relates to an algal reef and a manufacturing method thereof. Background Art

[0002] The coal ash discharged from thermal power plants, steel mills, etc. is mainly used as a raw material for cement, but in recent years, the demand for cement has decreased, so research is being conducted on its use for other purposes. As an example, attempts are being made to use coal ash in algal reef blocks that prevent rocky-shore denudation, a phenomenon that causes biological extinction in coastal waters. Patent Document 1 discloses an algal reef block that includes coal ash granular materials as aggregates and has gaps between the coal ash granular materials.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-229489 Summary of the invention

[0006] Problems to be solved by the invention

[0007] The algae reef block of Patent Document 1 is formed by mixing blast furnace cement mixed with blast furnace slag and the granular material of coal ash after manufacturing the granular material of coal ash. Therefore, there is a problem that the cost required for manufacturing is high and it is not suitable for mass production. Such a problem also exists when using biomass combustion ash instead of coal ash.

[0008] The present invention has been accomplished based on such a background, and an object of the present invention is to provide an algal reef that can be produced at low cost using ash obtained by burning coal or biomass, and a method for producing the same.

[0009] Solutions for solving problems

[0010] In order to achieve the above-mentioned object, the algal reef of the present invention comprises: ash powder obtained by burning coal or biomass and a curing agent that undergoes a chemical reaction and solidifies when mixed with the ash powder.

[0011] Effects of the Invention

[0012] According to the present invention, an algal reef that can be produced at low cost using ash obtained by burning coal or biomass and a method for producing the same can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram showing a situation where an algal reef according to an embodiment of the present invention is installed on the seabed.

[0014] Figure 2This is a flowchart showing the flow of a method for producing particles according to an embodiment of the present invention.

[0015] Figure 3 The present invention is a flowchart showing the process of using the algae reef according to the embodiment of the present invention.

[0016] Figure 4 This is a diagram showing the composition and production method of each matrix in Example 1.

[0017] Figure 5 These are photographs showing the appearance of Laminaria japonica spores attached to the surfaces of various substrates in filtered seawater in Example 1.

[0018] Figure 6 These are photographs showing the appearance of Laminaria japonica spores attached to the surfaces of various substrates in the PES modified medium in Example 1.

[0019] Figure 7 This is a graph showing the number of Laminaria japonica spores attached to the surface of each substrate per unit area in Example 1.

[0020] Fig. 8A This is a photograph of a state where one substrate in Example 1 is fixed to a rope.

[0021] Figure 8B It is for the general Fig. 8A The image was taken of the situation where the matrix was moored in the sea.

[0022] Fig. 9 These are photographs of the appearance of Japanese mazewort, Gracilaria, and laver attached to the surfaces of the respective substrates in Example 2.

[0023] Fig.10 This is a graph showing the number of individuals of Mazewort japonicum and Gracilaria japonica attached to the surface of each substrate in Example 2 and the coverage of Porphyra. DETAILED DESCRIPTION

[0024] Hereinafter, the algal reef and the manufacturing method thereof according to the embodiment of the present invention will be described in detail with reference to the accompanying drawings. In each of the drawings, the same or equivalent parts are marked with the same reference numerals.

[0025] Algae reefs are devices that allow algae to grow in water by attaching them to the surface. Algae reefs are set up in any place in water where you want to grow algae, such as the sea, river, lake, pond, or swamp. Algae reefs are preferably set up in water with algae seedlings attached to their surface. Algae attached to algae reefs can absorb carbon dioxide (CO2) in water through photosynthesis. 2), it can be any algae, for example, preferably brown algae such as kelp, wakame, hijiki and mozuku; red algae such as Japanese mazeweed, gracilaria, laver and agar.

[0026] As brown algae attached to the algae reef, seaweed of the Laminaria order, in particular, seaweed of the Laminariaceae, such as Saccharina japonica var. japonica, Saccharina japonica var. diabolica, Saccharina japonica var. ochotensis, Saccharina japonica var. religiosa, Mitsui kelp, Saccharina longissima, cat's foot kelp, and Kjellmaniella crassifolia, are preferred. Among the seaweeds of the Laminariaceae, spores that can swim in the sea, which are called zoospores, are attached to rocks and algae reefs. Then, the attached zoospores become male or female gametophytes, release sperm or eggs, and the two are fertilized and grow, thereby forming a sporophyte that can be observed visually. The following is an example of setting an algae reef on the seabed and growing the seaweed.

[0027] like Figure 1 As shown, the algae reef comprises: particles formed by forming and solidifying the kneaded material with a punching device and a bag through which a plurality of particles can pass. The particles can be in any shape, such as a cylindrical granular body, and the diameter and length thereof are preferably within the range of 5 mm to 20 mm, respectively.

[0028] The bag has an opening so that the algae attached to the particles extend outward, and is formed of, for example, a metal mesh. The bag is provided with an opening for the particles to be put in, and the opening is sealed with a rope-like member such as a rope before being placed in the sea. The algae reef formed by accommodating a plurality of particles in the bag is easier to lay on site than a block algae reef, and the size and shape can be adjusted, so the operation is also easy.

[0029] Next, the components contained in the pellets are described. The pellets are solidified by mixing a curing agent with the main component, coal ash. The curing agent is a material that solidifies by chemical reaction in a state containing coal ash. The curing agent solidifies itself to aggregate the coal ash and aggregate. The curing agent is preferably uniformly dispersed relative to the main component, coal ash.

[0030] Coal ash is a powder obtained by burning coal, and its main component is silicon dioxide (SiO 2 ), aluminum oxide (Al 2 O 3), mainly discharged from coal-fired power plants and steel plants. The weight ratio of coal ash in the particles is, for example, in the range of 60% to 90%, preferably in the range of 70% to 80%. Coal ash is, for example, fly ash. Fly ash is composed of fine spherical particles, which are ash generated by the combustion of coal and suspended together with the combustion gas and collected by a dust collector.

[0031] Coal ash can also be a powder of a desulfurizer that adsorbs nitrogen oxides in exhaust gas generated by the combustion of coal. The desulfurizer is a granular material formed by mixing coal ash and gypsum, and contains a large amount of coal ash. In addition to coal ash and gypsum, the desulfurizer that adsorbs nitrogen oxides also contains calcium oxide, silicate, and a trace amount of nitrogen.

[0032] The curing agent is, for example, powder of slaked lime or hemihydrate gypsum. It is also possible to mix either or both of them. The main component of slaked lime is calcium hydroxide, which has the property of curing in the air. The weight ratio of slaked lime in the particles is, for example, in the range of 5% to 20%, preferably in the range of 8% to 14%. Hemihydrate gypsum (calcined gypsum) is a kind of calcium sulfate (CaSO 4 ) is a mineral with gypsum as the main component, and has the property of reacting with water to be converted into dihydrate gypsum and solidified. The weight ratio of gypsum in the particles is, for example, in the range of 1% to 10%, preferably in the range of 2% to 6%.

[0033] In addition to the fly ash and the curing agent, the particles may also contain aggregates. Aggregates are materials that form the skeleton of the algae reef, such as granular bodies containing calcium carbonate and gravel. The particles may be composed of a single type of material or may contain multiple types of materials.

[0034] Granular bodies containing calcium carbonate are, for example, granular bodies obtained by crushing shells or limestone. Shells such as scallops, pearl oysters (Pinctada fucata), and oysters are mainly composed of calcium carbonate (CaCO 3 ). Limestone is a mineral with calcium carbonate as its main component. Granular bodies containing calcium carbonate may also contain calcium carbonate discharged after carbon dioxide is absorbed by a carbon dioxide absorption device. The calcium carbonate discharged by the carbon dioxide absorption device is placed in the exhaust system of a thermal power plant, etc., and is converted into calcium carbonate by calcium hydroxide (Ca(OH) 2 The weight ratio of the aggregate in the particles is, for example, in the range of 5% to 30%, preferably in the range of 10% to 20%.

[0035] A binder and water as needed may also be added to the pellets. The binder is a material that agglomerates fly ash and aggregates, and is, for example, clay, cement, soda ash, or an organic compound such as alginic acid or polyvinyl alcohol. The weight ratio of the binder in the pellets is, for example, in the range of 10% to 30%, preferably in the range of 15% to 25%. In addition, the amount of water added during the molding of the pellets may be appropriately set in consideration of the ease of molding and the strength of the pellets.

[0036] The particles may also be mixed with materials containing nutrient salts of algae, such as chicken manure combustion ash. Nutrient salts are salts necessary for algae growth, such as phosphates, nitrates, nitrites, ammonium salts, and silicates. Chicken manure combustion ash is ash obtained by burning chicken manure, and contains nutrient salts such as phosphates and potassium.

[0037] The algae reef of the embodiment has particles with the above technical characteristics, so kelp and other seaweeds can be attached to the surface, and carbon dioxide in the water can be efficiently absorbed. In addition, compared with the previous concrete algae reef, it can also promote the growth of seaweed, so it is preferred as a countermeasure for rocky reef coastal erosion in coastal waters.

[0038] The above are the technical characteristics of algal reefs and particles.

[0039] Next, refer to Figure 2 , the process of the method for manufacturing particles constituting algal reefs according to the embodiment is described. First, a mixer is used to mix materials including fly ash and a curing agent (step S11). When the materials contain water, the other materials except water are first air-mixed, and then water is added to the air-mixed materials, and further mixed.

[0040] Next, the material mixed in step S11 is formed into granules (step S12). The forming process may be any method, for example, it may be extrusion forming using an extrusion forming machine. In extrusion forming, the mixed material is passed through a plurality of holes formed in a plate and cut into a certain length by a cutter, thereby forming a cylindrical granular body.

[0041] Next, in order to solidify the molded body formed in the process of step S12, curing is performed (step S13). In the curing process, for example, a suitable method can be selected from water curing, steam curing, and calcining. In water curing, the strength of the particles is improved by curing by sinking the particles in water. In steam curing, the strength of the particles is improved earlier than curing in water by exposing the particles to high-temperature steam. In calcining, the particles are sintered at a high temperature of about 1000°C, for example.

[0042] The above is the flow of the method for producing pellets.

[0043] (How to use)

[0044] Next, refer to Figure 3 , the flow of the method for using the algae reef of the embodiment is described. First, algae seedlings, such as spores of kelp, are attached to the surface of particles and grown to a certain size in a water tank storing seawater (step S21).

[0045] Next, the plurality of particles that have been used to root the algae seedlings in step S21 are placed in a mesh bag that allows water to pass through, thereby making an algae reef with the algae seedlings attached to the surface (step S22). The amount of particles placed in the bag can be determined according to the shape of the seabed and the strength of the water flow. The process of placing the particles in the bag can be carried out in the facility where the algae seedlings are attached, or can be carried out near the site where the algae reef is set.

[0046] Next, the algae reef made in the process of step S22 is placed in water (step S23). At this time, the algae reef can be fixed to the seabed with anchors etc. as needed.

[0047] The above is the process of using algae reef.

[0048] As described above, the algae reef of the embodiment includes: ash powder obtained by burning coal and a curing agent that solidifies by chemical reaction when mixed with the ash powder. Therefore, the algae reef that effectively utilizes the coal ash discharged by burning coal can be manufactured in a simple procedure, and as a result, the algae reef can be manufactured at a low cost.

[0049] In addition, the algae reef of the embodiment can absorb a large amount of carbon dioxide in the water on the surface of the algae reef, so that the kelp forming a wide algae field can be attached, and the carbon dioxide emission in the power industry, etc. can be reduced. Compared with concrete algae reefs, the growth of various seaweeds is promoted, so it is also suitable for the coastal erosion phenomenon of rock reefs in coastal waters.

[0050] The algae reef of the embodiment may also contain calcium carbonate discharged after carbon dioxide is absorbed by the carbon dioxide absorption device as aggregate. By reusing such discharge from the carbon dioxide absorption device in the algae reef, it can further contribute to the reduction of carbon dioxide emissions in the power industry and the like.

[0051] The present invention is not limited to the above-described embodiment, and modifications as described below are possible.

[0052] (Variation Example)

[0053] In the above embodiment, coal ash obtained by burning coal is used as the main raw material, but the present invention is not limited thereto. Powder of biomass fuel ash obtained by burning biomass may also be used. Biomass includes, for example, wood, livestock manure, sewage sludge, and agricultural residues.

[0054] In the above embodiment, the algae reef is made by putting many particles into a metal mesh, but the present invention is not limited thereto. For example, a block having the same or equivalent composition as the particles may be used as the algae reef. The shape of the block may be any shape, for example, a cubic shape, a tetrapod shape (wave-breaking block shape).

[0055] In the above embodiment, the pellets are manufactured by extrusion molding, but the present invention is not limited thereto. For example, the pellets may be manufactured by methods other than extrusion molding, such as stamping molding, tumbling granulation, and stirring granulation.

[0056] In the above embodiment, the algae reef is placed in the water with the algae seedlings attached to the surface of the algae reef, but the present invention is not limited thereto. If the algae are growing vigorously in the water area, the algae reef may be placed in the water without attaching the algae seedlings to the surface of the algae reef.

[0057] In the above embodiment, the algae reef is set in water in a natural environment, but the present invention is not limited thereto. For example, a gas dissolving device may be used to absorb carbon dioxide in water, and the algae reef may be set in water with the carbon dioxide concentration in the water increased, thereby allowing algae to absorb carbon dioxide and further promoting the growth of algae.

[0058] The above embodiments are examples, and the present invention is not limited thereto. Various embodiments can be implemented within the scope of the subject matter of the invention described in the claims. The constituent elements described in the embodiments and modifications can be freely combined. In addition, the present invention also includes inventions equivalent to the inventions described in the claims.

[0059] Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples.

[0060] (Example 1)

[0061] In Example 1, block-shaped substrates A to E containing coal ash as a main component were prepared, and a culture test of Kamiyuki rishiri attached to the substrates A to E was conducted. The substrates A to E respectively had Figure 4 The composition shown is produced by kneading the raw materials and then curing them in water, steam or calcining. In water curing, for example, the mixture is stored at 20°C and 90% humidity for 2 weeks, or immersed in water at 20°C for 2 weeks. In steam curing, the mixture is sealed in a plastic bag immediately after molding and stored for 24 to 48 hours in a state of being exposed to steam at 90°C.

[0062] Next, two substrates A to E are immersed in the zoospore liquid of Laminaria japonica at a time to allow the zoospores to adhere to the surface. The zoospore liquid is prepared in the following order. First, slices of the sorus-forming part are cut from the collected Laminaria japonica spores, filtered with a cartridge filter, and washed with filtered seawater. Filtered seawater is seawater treated at a temperature of 121°C for 15 minutes. Next, after wiping the surface of the slice with a paper towel, wrap it with a paper towel, put it in a plastic bag and seal it, and store it in a cool and dark place overnight. The next day, the slices are immersed in filtered seawater to release the zoospores. Then, the number of zoospores is adjusted to 5000 / L.

[0063] Next, each substrate A to F was placed one at a time in 1 L of filtered seawater and PES (Provasoli Enriched Seawater) modified medium for culture, and cultured for 5 weeks at a water temperature of 10°C, an illumination of 5000 Lux, and a photoperiod of 12L:12D (12 hours light period, 12 hours dark period). PES modified medium is a nutrient-enriched medium made with seawater as the base to promote the growth of seaweed. The cultured individuals were observed once a week during the culture period, and the number of spores attached and the changes in the surface of the substrate were observed. In order to inhibit the reproduction of diatoms until the second week after the start of culture, 1 mg of germanium oxide was added to the culture solution. In addition, a portion of the culture solution was collected for each observation, and the concentrations of nitrogen and phosphorus, which are essential nutrients for the growth and development of seaweed, were measured using an automatic analyzer (BLTEC). For comparison, the same experiment was also conducted on substrate F made from commercially available concrete.

[0064] Figure 5 and Figure 6 The images are photos of the appearance of the spore bodies of Kelp Rishiri in filtered seawater and PES modified medium at the fifth week from the start of culture. In either culture medium, it was confirmed that the spore bodies of Kelp Rishiri grew on the surface of each substrate A to E. In either culture medium, spore bodies of a size observable with the naked eye appeared on the surface of each substrate A to E at the third and fourth weeks from the start of culture.

[0065] like Figure 7 As shown in Figure 2, when cultured in filtered seawater, the number of attachments per unit area in the fifth week of culture was approximately 4.5 cells / cm in matrix A. 2 , about 3.4 / cm in matrix B 2 In other matrices, the number of attachments tended to decrease compared with matrices A and B. When cultured in PES modified medium, the number of attachments per unit area at the 5th week of culture was about 4 / cm2 except for matrices E. 2 .

[0066] No morphological abnormalities such as shrinkage or twisting were found in the fronds of the sporophytes in any of the culture solutions and substrates A to E. In substrate B, the growth was faster than in the other substrates, and the cultured individuals tended to become larger. This is believed to be because the PO in the culture solution in substrate B was 4 NO was detected at a high concentration in the culture solution of the test area using substrate E. 3 -NO 2 -N (nitrate and nitrite) and PO 4 -P, but contrary to expectations, the growth of the sporophyte was poor and some of the fronds faded. This is believed to be because the excessive nitrogen and phosphorus supplied by the matrix E inhibited the growth and development of the sporophyte. It should be noted that in the matrix E, despite the addition of germanium oxide, diatoms also proliferated significantly.

[0067] In order to investigate the growth and development status in the actual environment, such as Fig. 8A As shown in FIG. 1 , the substrate with the spores of Laminaria japonica attached was fixed to a rope and set up in a culture raft in a fishing port. One month after the installation, observation was carried out with an underwater camera, and the results confirmed that Figure 8B As shown, the matrix did not disintegrate and the sporophyte grew.

[0068] (Example 2)

[0069] In Example 2, it was verified whether seaweeds other than kelp can grow in substrates A to C containing coal ash as a main component. Japanese mazewort, laver, and Gracilaria, which live in the waters off the coast of Hokkaido, were attached to substrates A to C containing coal ash as a main component, and a cultivation test was carried out in the same procedure as in Example 1.

[0070] First, 150 tetraspores of Japanese mazewort and Gracilaria were respectively spread on the surface of each substrate A to C, and 2 mg of filaments of Porphyra were spread on the surface of each substrate A to C, which were immersed in 2L of seawater, and the tetraspores of Japanese mazewort and Gracilaria, and the filaments of Porphyra were cultured in the following order. First, the collected female gametophytes of Japanese mazewort, Gracilaria, and gametophytes of Porphyra were washed with filtered seawater. Then, the fruit-carrying parts of Japanese mazewort and Gracilaria were cut off, and the zygospore-forming parts of Porphyra were cut off, and the respective slices were immersed in filtered seawater. Then, the released fruit spores and zygospores were collected, respectively, and they were cultured for about 5 to 7 months, thereby obtaining tetraspores of Japanese mazewort and Gracilaria, and filaments of Porphyra. The tetraspore forming part was cut out from the tetraspore of Mazewort and Gracilaria japonica, and immersed in filtered seawater to obtain tetraspores. The filamentous body of Porphyra was carefully chopped with a sterilized scalpel.

[0071] Next, each substrate A to C attached with tetraspores of Japanese mazewort and Gracilaria or filaments of Porphyra was transferred to 1L of PES modified medium, and cultured for 8 weeks at a water temperature of 10°C for Japanese mazewort and 20°C for Gracilaria and Porphyra. The illumination was 5000Lux and the photoperiod was 12L:12D. The cultured individuals were observed once a week during the culture period, and the number of germinated individuals was counted for Japanese mazewort and Gracilaria. In addition, for Porphyra, the coverage of the substrate surface was calculated after the 4th week of culture when filament growth and improvement in color tone began to be observed. It should be noted that coverage refers to the proportion of the surface covered by a specific species in a plant community.

[0072] Fig. 9 The following is a photograph of the appearance of tetraspores of Japanese mazewort and Gracilaria, and filaments of Porphyra in the fifth week from the start of culture. Fig. 9 As shown, tetraspores of Mazewort japonicus and Gracilaria japonica and filaments of Porphyra rapa were confirmed to be growing on the surface of each substrate A to C.

[0073] Regarding the Japanese mazewort and Gracilaria, individuals of a size that can be observed with the naked eye appeared in each substrate A to C in the fourth week of cultivation. Fig.10 As shown, at the time point when the cultivation experiment ended, the largest number of individuals of Japanese mazewort was attached to substrate C, and the largest number of individuals of Gracilaria were attached to substrate B. No abnormalities in the morphology of Japanese mazewort and Gracilaria were found in each substrate A to C. Gracilaria was cultivated for about 2 to 3 weeks after the end of the cultivation experiment, and as a result, the maturation of male and female gametophytes was confirmed, and the formation of capsules was also observed. There was no significant difference in the coverage of Porphyra filaments between each substrate A to C, and no abnormalities were found in the tissue of Porphyra filaments when observed with an optical microscope.

[0074] This application is based on Japanese Patent Application No. 2022-83804 filed on May 23, 2022, and the specification, claims, drawings and abstract thereof are also included therein. The disclosure in the above Japanese Patent Application is incorporated herein by reference in its entirety.

[0075] Industrial Applicability

[0076] The algal reef and the method for producing the algal reef of the present invention are useful because they can be produced at low cost using ash obtained by burning coal or biomass.

Claims

1. An algal reef, wherein: The invention comprises: ash powder obtained by burning coal or biomass; and a curing agent which is cured by chemical reaction when mixed with the ash powder.

2. The algal reef according to claim 1, wherein: The curing agent includes at least one of slaked lime and hemihydrate gypsum.

3. The algal reef according to claim 1 or 2, wherein: The algal reef includes at least one of granular bodies containing calcium carbonate and gravel as aggregate.

4. The algal reef according to claim 3, wherein: The granular body containing calcium carbonate is produced by the reaction of calcium hydroxide with carbon dioxide in a carbon dioxide absorption device.

5. The algal reef according to any one of claims 1 to 4, wherein: In the algal reef, the powder including the ash and the granules of the curing agent are contained in a bag through which liquid can pass.

6. The algal reef according to claim 5, wherein: Seedlings of algae cultured in filtered seawater or culture medium are attached in advance to the surface of the particles.

7. A method for producing an algal reef, wherein: include: A step of kneading ash powder obtained by burning coal or biomass and a curing agent that is cured by chemical reaction when mixed with the ash powder; The process of molding the mixed material; and The process of solidifying the molded material.

Images