Greening materials

Abstract

To provide a greening material using a substitute material which is inexpensive and can be easily secured.SOLUTION: In a greening material 1, neutralized combustion ash, which is neutralized by bringing a carbon dioxide gas containing carbon dioxide into contact with biomass combustion ash generated by combustion of biomass, a dehydrated purified water generating soil, and bark compost are mixed. The greening material has a pH of 6 or more and 9 or less, an electric conductivity of less than 0.15 S / m, a saturation water permeability coefficient exceeding 10-4 m / s, and an effective water content exceeding 120 L / m3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This disclosure relates to greening materials.

Background Art

[0002] Conventionally, there is known a greening material obtained by mixing purified water generation soil generated at a water purification plant, coconut shell fibers as a moisture adjusting material, and clinker ash (coal ash) as a drainage material. For example, Patent Document 1 discloses a vegetation base material added with purified water generation soil, bark compost, peat moss, crushed coconut, and charcoal.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the coconut shell fibers used in conventional greening materials are expensive because they are imported and purchased from overseas. In addition, it is expected that clinker ash will be difficult to secure as coal-fired power generation is reduced in the future.

[0005] This disclosure has been made in view of the above problems, and an object thereof is to provide a greening material using alternative materials that are low-cost and easy to secure.

Means for Solving the Problems

[0006] To achieve the above object, a greening material according to one aspect of the present disclosure is kneaded with neutralized combustion ash obtained by neutralizing biomass combustion ash generated by burning biomass by bringing it into contact with a carbon dioxide-containing carbon gas, dehydrated purified water generation soil, and bark compost, and has a pH of 6 or more and 9 or less, an electrical conductivity of less than 0.15 S / m, and a saturated hydraulic conductivity of 10 , ,

[0006] , , , , , , , ,

[0004] , , , , , , , , , , -4 , ,

[0003] ,

[0005] , m / s exceeded, effective moisture content was 120 L / m³ 3 It is excessive.

[0007] In a desirable form of the greening material, the biomass combustion ash is the main ash.

[0008] A desirable form of greening material is the addition of acidic fertilizer.

[0009] In a desirable form of the greening material, the acidic fertilizer includes a phosphate fertilizer, a nitrogen fertilizer, or an organic fertilizer, and has a pH of 6 or higher and 8 or lower. [Effects of the Invention]

[0010] According to this disclosure, it is possible to provide greening materials that use alternative materials that are low cost and easy to obtain. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic diagram showing a manufacturing system for producing greening materials according to the embodiment. [Figure 2] Figure 2 is a schematic diagram showing an example of a test apparatus equivalent to the neutralization treatment apparatus shown in Figure 1. [Figure 3] Figure 3 is a graph showing the results of the pH-dependent test of biomass combustion ash. [Figure 4] Figure 4 is a graph showing the relationship between the amount of acidic fertilizer added and pH. [Figure 5] Figure 5 shows the germination status on the 7th day after sowing in the plant damage test. [Figure 6] Figure 6 is a graph showing the plant height 21 days after sowing in the plant damage experiment. [Figure 7] Figure 7 shows the growth status of the plants in the plant damage experiment 21 days after sowing. [Modes for carrying out the invention]

[0012] The present disclosure will be described in detail below with reference to the drawings. However, the present disclosure is not limited to the following embodiments. Furthermore, some components in the following embodiments are substituted and easily replaceable by those skilled in the art, or are substantially identical. In addition, various omissions, substitutions, or modifications of the components in the embodiments described below can be made without departing from the spirit of the present disclosure. In the following embodiments, components necessary for illustrating the embodiments of the present disclosure will be described, and other components will be omitted.

[0013] (Embodiment) Figure 1 is a schematic diagram showing a manufacturing system for producing the greening material 1 of the embodiment. The greening material 1 is a soil mixture of neutralized combustion ash 10, which is obtained by neutralizing biomass combustion ash 12 generated by the combustion of biomass 11; water treatment soil 20 generated at a water treatment plant; bark compost 30; and acidic fertilizer 40. In the following description, along with the flow of manufacturing the greening material 1 using the manufacturing system shown in Figure 1, the neutralized combustion ash 10, water treatment soil 20, bark compost 30, and acidic fertilizer 40 that constitute the greening material 1 will also be described as appropriate.

[0014] In this embodiment, biomass 11 is woody biomass. Woody biomass includes forest residues such as branches, leaves, twigs, and stumps obtained from forests, sawdust, bark, scraps, backing boards and other waste materials from sawmills, and industrial waste such as construction waste and demolition materials. In this embodiment, the biomass power generation facility 50 is a facility that generates electricity by directly burning biomass 11 to turn a steam turbine, or a facility that generates electricity by operating an engine with combustible gas generated by directly burning biomass 11. In the biomass power generation facility 50, the burning of biomass 11 generates biomass combustion ash 12 and exhaust gas containing carbon dioxide (CO2).

[0015] The biomass combustion ash 12 is a residue recovered from a combustion furnace or the like that burns biomass 11. In an embodiment, the biomass combustion ash 12 represents the main ash recovered from the bottom of a combustion furnace or the like, and is distinguished from fly ash that is entrained with combustion gas and recovered by a dust collector. The components of the biomass combustion ash 12 mainly include calcium oxide (CaO), silicon dioxide (SiO2), aluminum oxide (Al2O3), and the like.

[0016] The biomass combustion ash 12 generated in the biomass power generation facility 50 is transported to the neutralization treatment device 60. Further, the exhaust gas containing carbon dioxide generated by the combustion of the biomass 11 is drawn from in front of the chimney of the combustion furnace or from an inspection hole of the chimney. The exhaust gas is sent to the neutralization treatment device 60 after removing acidic components in the exhaust gas with a treatment device such as a denitration device etc.

[0017] In the neutralization treatment device 60, a treatment is performed to lower the pH and neutralize by causing the biomass combustion ash 12 transported from the biomass power generation facility 50 to contact with exhaust gas containing carbon dioxide (hereinafter referred to as carbon dioxide gas) to carbonate it. In the following description, the neutralized biomass combustion ash 12 is referred to as neutralized combustion ash 10. The carbon dioxide gas that reacts with the biomass combustion ash 12 does not necessarily have to be the exhaust gas generated in the biomass power generation facility 50, and may be exhaust gas generated from a thermal power plant that uses coal, oil, natural gas, etc. as fuel, a factory such as a cement manufacturing factory, a chemical plant, an incineration facility, etc.

[0018] The neutralization treatment device 60 includes, for example, a container type, a yard pit type, a mechanical stirring type, etc. The container type neutralization treatment device 60 is, for example, a substantially rectangular parallelepiped portable container that can be placed on the loading platform of a vehicle, and is useful when the transportation distance is long. The container includes a double - floor treatment tank having a partition wall that divides the internal space in the vertical direction. The partition wall is a plate - like member parallel to the bottom surface of the treatment tank and has a plurality of ventilation holes. In the container type neutralization treatment device 60, the loaded biomass combustion ash 12 is placed on the partition wall. The carbon dioxide gas is introduced into the space below the partition wall and contacts the biomass combustion ash 12 from below through the ventilation holes of the partition wall.

[0019] The yard-pit type carbonation treatment device 60 includes, for example, a large treatment yard capable of stacking biomass combustion ash 12, and a gas supply nozzle for injecting carbon dioxide into the stacked layers of biomass combustion ash 12. The yard-pit type carbonation treatment device 60 is useful when the amount of biomass combustion ash 12 discharged is large. Alternatively, the treatment yard may be installed indoors with walls and a ceiling, and carbon dioxide may be introduced indoors to bring the carbon dioxide into contact with the stacked biomass combustion ash 12 from above.

[0020] The mechanically agitated neutralization treatment device 60 is a device that can automatically agitate the inside of a treatment tank containing biomass combustion ash 12 while supplying carbon dioxide gas to it. Alternatively, a container-type neutralization treatment device 60 may also be provided with an agitation mechanism. By agitating the biomass combustion ash 12 during the treatment process in which it is exposed to carbon dioxide gas, the biomass combustion ash 12 can be uniformly exposed to carbon dioxide gas.

[0021] The biomass combustion ash 12 undergoes carbonate formation by absorbing carbon dioxide. Specifically, calcium components such as calcium oxide contained in the biomass combustion ash 12 undergo carbonate formation, producing calcium carbonate (CaCO3). In other words, in the neutralization treatment device 60, carbon dioxide is fixed to the biomass combustion ash 12 as carbonate. Furthermore, the neutralization treatment makes heavy metals such as lead (Pb) contained in the biomass combustion ash 12 less soluble and reduces its electrical conductivity (EC). The neutralized biomass combustion ash 12, i.e., the neutralized combustion ash 10, is transported to the kneader 90.

[0022] Here, the results of the inventors' verification of the change in pH buffering capacity due to the neutralization treatment will be explained with reference to Figures 2 and 3. Figure 2 is a schematic diagram showing an example of a test apparatus 60A corresponding to the neutralization treatment apparatus 60 shown in Figure 1. Figure 3 is a graph showing the results of the pH dependence test of biomass combustion ash 12.

[0023] In this verification, the change in pH was measured when nitric acid was added to neutralized combustion ash 10, which had undergone neutralization treatment, and to biomass combustion ash 12, which had not undergone neutralization treatment. The neutralized combustion ash 10 used in this verification was prepared by adding water to biomass combustion ash 12 to a moisture content of 15 wt%, kneading it, and then filling the test apparatus 60A shown in Figure 2 with a weight of 2500 g DW and performing neutralization treatment. The biomass combustion ash 12 that had not undergone neutralization treatment used in this verification was prepared by adding water to a moisture content of 15 wt% and kneading it.

[0024] In one embodiment, the test apparatus 60A includes a column made of polyvinyl chloride. The test apparatus 60A comprises a reaction section 61, a resin mesh 62, and an air supply section 63. The reaction section 61 is a cylindrical shape extending vertically and is the part filled with biomass combustion ash 12. The resin mesh 62 is a resinous mesh that closes the lower end of the reaction section 61 and allows the biomass combustion ash 12 to be placed on top of it.

[0025] The air supply section 63 is located below the reaction section 61 and the resin mesh 62, and communicates with the reaction section 61 via the resin mesh 62. The air supply section 63 is filled with a lower support material 64. In this embodiment, the lower support material 64 is gravel. The air supply section 63 has an air inlet 65, which receives carbon dioxide gas. The air inlet 65 supplies carbon dioxide gas to the air supply section 63 via an air supply line 66. A flow meter 67 is provided in the air supply line 66. The flow meter 67 measures the flow rate of carbon dioxide gas supplied to the air supply section 63.

[0026] In the test apparatus 60A, with biomass combustion ash 12 placed on a resin mesh 62, carbon dioxide gas is introduced into the air supply section 63, and the carbon dioxide gas passes through the resin mesh 62 and comes into contact with the biomass combustion ash 12 from below. In this verification, neutralization treatment was carried out under the conditions of a carbon dioxide concentration of 10%, an airflow rate of 0.7 L / m, an airflow time of 24 hours, and a carbon dioxide supply amount of 80 g-CO2 / kgDW.

[0027] The horizontal axis of Figure 3 represents the amount (μL) of nitric acid (HNO3) added to biomass combustion ash 12 and neutralized combustion ash 10, respectively, and the vertical axis of Figure 3 represents the pH of biomass combustion ash 12 and neutralized combustion ash 10, respectively. In Figure 3, "Bottom Ash (Untreated)" is biomass combustion ash 12 that has not undergone neutralization treatment, and "Bottom Ash (Neutralized)" is neutralized combustion ash 10 in which biomass combustion ash 12 has undergone neutralization treatment using test apparatus 60A. As shown in Figure 3, the pH of neutralized combustion ash 10 is lower than that of biomass combustion ash 12. Furthermore, the pH decreases with the addition of nitric acid. In other words, the pH buffering capacity decreases with the implementation of neutralization treatment.

[0028] The water treatment soil 20 shown in Figure 1 is clayey soil generated during the water treatment process at a water treatment plant. At the water treatment plant, for example, in the sedimentation tank 70, the sludge 21 is separated by sedimentation together with suspended solids, powdered activated carbon, and coagulants. The sludge 21 is then transferred to a dewatering facility 80 for dewatering. The dewatering facility 80 may dewater by mechanical means such as a press, or by drying in the sun. The dewatered sludge 21 becomes water treatment soil 20 and is then transferred to a mixer 90.

[0029] In the mixing machine 90, neutralized combustion ash 10, purified water-generated soil 20, bark compost 30, and acidic fertilizer 40 are mixed to produce greening material 1. Bark compost 30 is an organic fertilizer made by fermenting tree bark. Acidic fertilizer 40 is, for example, a phosphate fertilizer or a nitrogen fertilizer. The pH value of greening material 1 is adjusted by adding acidic fertilizer 40.

[0030] Greening material 1 consists of neutralized combustion ash 10, purified water soil 20, and bark compost 30, which are put into a mixer 90 in a ratio of 4-10:3-5:0.3-1 and mixed by the mixer 90 for 5-10 seconds. Alternatively, the mixer 90 may first mix the neutralized combustion ash 10 and purified water soil 20 for 5-10 seconds, and then mix in the bark compost 30 for 5-10 seconds.

[0031] When mixing the neutralized combustion ash 10, purified water-generated soil 20, and bark compost 30 in the mixer 90, the pH value of the greening material 1 may be further adjusted by adding acidic fertilizer 40. Table 1 is a table showing the physical performance of the greening material 1 of the embodiment. As shown in Table 1, the greening material 1 has a pH of 6 or more and 9 or less, an electrical conductivity of less than 0.15 S / m, and a saturated water permeability coefficient of 10 -4 m / s exceeded, effective moisture content was 120 L / m³ 3 It is manufactured in excess.

[0032] [Table 1]

[0033] Here, the inventors of this disclosure will explain the results of their verification regarding the change in pH due to the addition of acidic fertilizer 40, with reference to Figure 4. Figure 4 is a graph showing the relationship between the amount of acidic fertilizer 40 added and pH. "Before addition" in Figure 4 refers to the pH of a prototype soil prepared by mixing neutralized combustion ash 10, purified water soil 20, and bark compost 30 in a ratio of 4-10:3-5:0.3-1.

[0034] Furthermore, the "phosphate fertilizer" shown in Figure 4 refers to the pH of the prototype soil after adding phosphate fertilizer as acid fertilizer 40 at addition rates of 0.5 wt%, 1 wt%, 3 wt%, and 5 wt%, respectively, to the prototype soil before addition and mixing. Furthermore, the "nitrogen fertilizer" shown in Figure 4 refers to the pH of the prototype soil after adding phosphate fertilizer as acid fertilizer 40 at the respective proportions to neutralized combustion ash 10, water purification soil 20, and bark compost 30 and mixing. Furthermore, the "organic fertilizer" shown in Figure 4 refers to the pH of the prototype soil after adding organic fertilizer as acid fertilizer 40 at addition rates of 0.1 wt%, 0.3 wt%, 0.5 wt%, and 1.0 wt%, respectively, and mixing.

[0035] As shown in Figure 4, the trial soil without added acidic fertilizer 40 had a pH of 8.1, slightly exceeding the target pH of 8.0 shown in Table 1. When phosphate fertilizer was added to the trial soil, the target pH was achieved at an addition rate of 1 wt% or more. When nitrogenous fertilizer was added to the trial soil, the target pH was achieved at an addition rate of 3 wt%. When organic fertilizer was added to the trial soil, the target pH was achieved at an addition rate of 0.3 wt% or more. It is preferable to determine the addition rate of acidic fertilizer 40 in the greening material 1 so as to achieve the target pH, depending on the mixing ratio of neutralized combustion ash 10, purified water soil 20, and bark compost 30, and the type of acidic fertilizer 40 added.

[0036] Next, the performance of the greening material 1 of the embodiment will be described by the inventors of this disclosure, with reference to Table 2 and Figures 5 to 7. In this verification, komatsuna was sown in masado soil W, kuroboku soil X, commercially available soil Y, commercially available soil Z, prototype soil A, prototype soil B, prototype soil C, and prototype soil D, and the germination status on the 3rd and 7th day after sowing, and the growth status on the 21st day after sowing were verified.

[0037] Prototype soil A is a mixture of 10 parts neutralized combustion ash (after neutralization treatment), 20 parts water treatment soil, 30 parts bark compost, 40 parts acidic fertilizer for pH adjustment, and fertilizer for plant growth. Prototype soil B is a mixture of 10 parts neutralized combustion ash (after neutralization treatment), 20 parts water treatment soil, 30 parts bark compost, and 40 parts acidic fertilizer for pH adjustment. Prototype soil C is a mixture of 10 parts neutralized combustion ash (after neutralization treatment), 20 parts water treatment soil, 30 parts bark compost, and fertilizer for plant growth. Prototype soil D is a mixture of 10 parts neutralized combustion ash (after neutralization treatment), 20 parts water treatment soil, and 30 parts bark compost. In addition, superphosphate of lime was added as the acidic fertilizer 40.

[0038] Table 2 shows the results of the germination test. Figure 5 shows the germination status on day 7 of sowing in the plant damage test. In Table 2, "pH adjustment treatment" indicates whether or not acidic fertilizer 40 was mixed in. Also in Table 2, "fertilization" indicates whether or not growth fertilizer was mixed in. As shown in Table 2 and Figure 5, the trial soils A and B, which underwent pH adjustment treatment, achieved germination rates comparable to those of masado soil W, kuroboku soil X, and commercially available soils Y and Z. In contrast, the trial soils C and D, which did not undergo pH adjustment treatment, did not exceed the general target value of 80% for germination rate.

[0039] [Table 2]

[0040] Figure 6 is a graph showing the plant height 21 days after sowing in the plant damage test. Figure 7 is a diagram showing the growth status 21 days after sowing in the plant damage test. As shown in Figures 6 and 7, comparable growth conditions were observed in the experimental soils A, B, C, and D compared to Kuroboku soil and commercially available soils X and Y. In particular, the average plant height in experimental soils A and B, which underwent pH adjustment treatment, grew higher than that of commercially available soils X and Y.

[0041] As described above, the greening material 1 of the embodiment is made by mixing neutralized combustion ash 10, which is obtained by neutralizing biomass combustion ash 12 generated by the combustion of biomass 11 by bringing it into contact with carbon dioxide gas, dewatered purified water soil 20, and bark compost 30, and has a pH of 6 to 9, an electrical conductivity of less than 0.15 S / m, and a saturated water permeability coefficient of 10 -4 m / s exceeded, effective moisture content was 120 L / m³ 3 It is in excess.

[0042] Combustion ash has excellent hygroscopic and water-absorbing properties. That is, by using biomass combustion ash 12, obtained by burning biomass 11, as a substitute for conventional moisture-adjusting materials, a highly permeable greening material 1 can be obtained. Furthermore, by neutralizing the biomass combustion ash 12 by exposing it to carbon dioxide before mixing it with the water purification soil 20, heavy metals such as lead contained in the biomass combustion ash 12 can be made less soluble, thereby suppressing the leaching of heavy metals such as lead from the greening material 1 containing the neutralized combustion ash 10. In addition, since the carbon dioxide used in the neutralization treatment can be exhaust gas emitted when burning biomass 11, costs can be reduced by effectively utilizing carbon dioxide in addition to the biomass combustion ash 12 generated at the biomass power generation facility 50. Furthermore, by fixing the exhaust gas generated at the biomass power generation facility 50 as carbonate, the amount emitted into the atmosphere can be reduced, contributing to the formation of a decarbonized society.

[0043] Furthermore, in the greening material 1 of this embodiment, the biomass combustion ash 12 is bottom ash. Bottom ash has a porous structure, and this porous structure provides excellent moisture absorption, water absorption, drainage, and air permeability. In other words, by using bottom ash from the biomass combustion ash 12 obtained by burning biomass 11 as a substitute for conventional drainage material, a greening material 1 with high drainage can be obtained.

[0044] Furthermore, the greening material 1 of the embodiment has acidic fertilizer 40 added to it. The neutralized combustion ash 10 has its pH lowered by neutralizing the alkaline biomass combustion ash 12. If the pH does not reach the target value (pH ≤ 8) depending on the components and mixing ratio of the neutralized combustion ash 10, purified water soil 20, and bark compost 30, the pH can be adjusted by adding acidic fertilizer 40. The greening material 1 of the embodiment in which pH adjustment treatment has been performed by adding acidic fertilizer 40 has a pH of 6 or more and 8 or less.

[0045] Furthermore, in the greening material 1 of the embodiment, the acidic fertilizer 40 includes a phosphate fertilizer, a nitrogen fertilizer, or an organic fertilizer, and has a pH of 6 to 8. Adding a phosphate fertilizer or a nitrogen fertilizer is particularly useful when the soil, which is a mixture of neutralized combustion ash 10, purified water soil 20, and bark compost 30, has low levels of phosphorus or nitrogen, thereby allowing for a suitable adjustment of the pH. In addition, since organic fertilizers do not contain heavy metals, heavy metal content can be reduced.

[0046] Furthermore, each configuration described in each embodiment may be combined with other configurations within each embodiment, without departing from the spirit of the invention. These configurations may also be combined with configurations in other embodiments different from those in each embodiment, without departing from the spirit of the invention. Additionally, various modifications may be made without departing from the spirit of the invention. [Explanation of symbols]

[0047] 1. Greening materials 10 Neutralized combustion ash 11. Biomass 12. Biomass combustion ash 20. Water treatment sludge 21 Sludge 30 bark compost 40 Acid fertilizer 50 Biomass power generation facilities 60 Neutralization treatment device 60A Test Apparatus 61 Reaction section 62 Resin mesh 63 Air supply section 64 Lower support material 65 Air supply port 66 Air intake line 67 Flow meter 70 Sedimentation Tank 80 Dehydration equipment 90 Mixing machine

Claims

1. Neutralized combustion ash, which is obtained by neutralizing the bottom ash (after removing fly ash) from biomass combustion ash by exposing it to carbon dioxide to reduce its pH buffering capacity and electrical conductivity, is mixed with dewatered treated water purification soil and bark compost. pH is between 6 and 9, electrical conductivity is less than 0.15 S / m, and saturated water permeability coefficient is 10 －４ m / s exceeding, effective moisture content 120 L / m ３ Excess greening materials.

2. Acidic fertilizer is added further. Greening material according to claim 1.

3. The aforementioned acidic fertilizer includes phosphate fertilizer, nitrogen fertilizer, or organic fertilizer. The pH is between 6 and 8. The greening material according to claim 2.

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