Method and device for producing organic material with enhanced nitrogen content, plant cultivation method, and method for improving soil

Abstract

This method for producing an organic material comprises: a step (A) in which a first gas containing nitrogen and oxygen is converted into arc plasma by arc discharge to obtain a second gas containing nitrogen oxides; and a step (B) in which the second gas is supplied to a solid organic material. In the step (A), the first gas may be converted into arc plasma and ejected in a plasma jet flow state, and in the step (B), the second gas after ejection thereof may be cooled to a temperature of 50°C or less and supplied to the organic material.

Description

Method and apparatus for producing nitrogen-enhanced organic materials, as well as method for cultivating plants and method for improving soil.

[0001] The present invention relates to a method and apparatus for producing an organic material with enhanced nitrogen content, as well as a method for cultivating plants and a method for improving soil. This application claims priority pursuant to U.S. Provisional Application No. 63 / 695,859, filed in the United States on September 18, 2024, the contents of which are incorporated herein by reference.

[0002] Conventionally, nitrogen (N ２ A known technique involves plasma-generating ) and bringing it into contact with organic matter to increase the nitrogen content of organic materials.

[0003] For example, Patent Document 1 discloses experimental results showing that by using a low-pressure plasma generator or a dielectric barrier discharge (DBD) plasma generator, plasma-generated nitrogen was reacted with organic fertilizer, and the nitrate ion concentration and nitrite ion concentration of the organic fertilizer could be increased.

[0004] Japanese Patent Publication No. 2022-65924

[0005] However, the technology disclosed in Patent Document 1, as shown in Tables 1 and 2 of Patent Document 1, had the problem that even after plasma irradiation, the nitrate ion concentration and nitrite ion concentration were both in the μmol / L range, resulting in a small nitrogen enhancement effect.

[0006] This invention has been made in view of these circumstances, and aims to provide a novel technology that can significantly increase the nitrogen content of organic materials compared to conventional methods.

[0007] To solve the above problems, one aspect of the present invention includes the following aspects: [1] A method for producing an organic material with enhanced nitrogen content, comprising the steps of (A) generating an arc plasma from a first gas containing nitrogen and oxygen by arc discharge to obtain a second gas containing nitrogen oxides, and (B) supplying the second gas to a solid organic material.

[0008] [2] The manufacturing method according to [1], wherein in step (A), the first gas is converted into an arc plasma and ejected in the form of a plasma jet, and in step (B), the ejected second gas is supplied to the organic material after being cooled to a temperature of 50°C or lower.

[0009] [3] The above step (A) involves temporarily heating the arc plasma gas to 10 ３ The manufacturing method according to [2], comprising a step of high-speed cooling at a rate of K (Kelvin) / s or higher.

[0010] [4] The manufacturing method according to [1] or [2], which includes a step of passing the first gas through water to add water to the first gas prior to step (A).

[0011] [5] The manufacturing method according to any one of [1] to [4], wherein the nitrogen content to be enhanced includes at least one selected from the group consisting of ammonia, nitrate, nitrite, urea, and ions thereof.

[0012] [6] The manufacturing method according to any one of [1] to [5], wherein the organic material comprises one or more selected from the group consisting of plant compost, leaf mold, bagasse, and livestock manure compost.

[0013] [7] The manufacturing method according to any one of [1] to [6], wherein in step (B), the second gas is supplied into a container containing the organic material, and the container is left standing for 100 seconds or more with the second gas filling it.

[0014] A method for cultivating plants, comprising the steps of: producing a nitrogen-enriched solid organic material by a manufacturing method described in any one of items [8], [1], to [7]; and cultivating plants in soil to which the nitrogen-enriched solid organic material has been applied.

[0015] A soil improvement method comprising the steps of: producing a solid organic material with enhanced nitrogen content by a manufacturing method described in any one of items [9], [1], to [7]; and applying the solid organic material with enhanced nitrogen content to soil.

[0016]

[10] A manufacturing apparatus for nitrogen-enhanced organic materials, comprising: an arc plasma generation unit having an arc plasma generation space surrounded by a plurality of electrodes, which generates arc plasma by performing an arc discharge in the arc plasma generation space; a first gas supply unit which supplies a first gas containing nitrogen and oxygen to the arc plasma generation space; and an organic material arrangement unit where solid organic materials are arranged, wherein a second gas containing nitrogen oxides obtained by arc plasmaization of the first gas in the arc plasma generation unit is supplied to the organic material arrangement unit.

[0017]

[11] The manufacturing apparatus according to

[10] , comprising a plasma jet ejection unit that ejects gas that has been turned into arc plasma in the arc plasma generation unit in the form of a plasma jet stream, and a conduit that transfers the gas ejected from the plasma jet ejection unit to the organic material placement unit, wherein the gas ejected from the plasma jet ejection unit is cooled to a temperature of 50°C or less in the conduit before being supplied to the organic material placement unit.

[0018]

[12] The conduit is surrounded by a cooling pipe for transferring cooling water, and at least a portion of the conduit and the cooling pipe is made of metal, and the gas ejected from the plasma jet nozzle is at least temporarily 10 ３ The manufacturing apparatus described in

[11] , configured to enable high-speed cooling at a rate of K (Kelvin) / s or higher.

[0019]

[13] A manufacturing apparatus according to any one of

[10] to

[12] , comprising a tank for containing water, a water addition unit for adding water to the first gas in the tank, wherein the first gas to which water has been added by the water addition unit is supplied to the arc plasma generation space by a first gas supply unit.

[0020]

[14] The manufacturing apparatus according to any one of

[10] to

[13] , wherein the arc plasma generating unit is configured as an arc thermal plasma torch.

[0021]

[15] The manufacturing apparatus according to any one of

[11] to

[14] , wherein the organic material is arranged in the organic material arrangement section, separated from the tip of the plasma jet stream by a second gas flow path of at least 150 mm.

[16] The manufacturing apparatus according to any one of

[10] to

[15] , wherein the organic material is arranged in the organic material arrangement section, separated from the tip of the plasma jet stream by a second gas flow path of at least 1000 mm.

[0022]

[17] The manufacturing apparatus according to any one of

[10] to

[16] , wherein the organic material arrangement section is a container for containing the organic material and the second gas.

[0023]

[18] The manufacturing apparatus according to

[14] , further comprising a cooling mechanism for the plurality of electrodes and a gas flow rate adjustment mechanism, wherein the arc thermal plasma torch is a non-transition type DC arc.

[0024] The present invention may also include the following embodiments: [P1] A method for producing an organic fertilizer with enhanced nitrogen content, comprising the steps of: converting at least a portion of a nitrogen-containing gas into an arc plasma by arc discharge; and supplying the nitrogen modified by the arc plasma to a mainly solid organic fertilizer located downstream of the arc plasma.

[0025] [P2] The manufacturing method according to the method, wherein the nitrogen content to be enhanced is at least one selected from the group consisting of ammonia, nitrate, nitrite, urea, and ions thereof.

[0026] [P3] The manufacturing method according to [P1] or [P2], wherein the organic fertilizer includes plant compost.

[0027] A method for cultivating plants, comprising the steps of: producing a mainly solid organic fertilizer with enhanced nitrogen content by a manufacturing method described in any one of the items [P4], [P1] to [P3]; and cultivating plants in soil to which the nitrogen-enhanced organic fertilizer has been applied.

[0028] A method for improving soil, comprising the steps of: producing a mainly solid organic fertilizer with enhanced nitrogen content by a manufacturing method described in any one of the items [P5], [P1] to [P3]; and applying the nitrogen-enhanced organic fertilizer to soil.

[0029] [P6] An apparatus for producing nitrogen-enhanced organic fertilizer, comprising: an arc plasma generator having an arc plasma generation space surrounded by a plurality of electrodes; a nitrogen-containing gas supply unit for supplying nitrogen-containing gas to the arc plasma generation space; and an organic fertilizer placement unit provided downstream of the arc plasma generation space, where solid organic fertilizer is mainly placed, wherein nitrogen modified by the arc plasma generator is accumulated in the organic fertilizer in the organic fertilizer placement unit.

[0030] [P7] The apparatus for producing nitrogen-enhanced organic fertilizer according to [P6], wherein the organic fertilizer is arranged in the organic fertilizer arrangement section at a distance of at least 150 mm from the arc plasma generation space.

[0031] [P8] The apparatus for producing nitrogen-enhanced organic fertilizer according to [P6] or [P7], wherein the organic fertilizer is placed in the organic fertilizer placement section at a distance of at least 1000 mm from the arc plasma generation space.

[0032] [P9] The apparatus for producing nitrogen-enhanced organic fertilizer according to any one of [P6] to [P8], wherein the organic fertilizer placement section further includes a first placement section connected to the arc plasma generation space and a second placement section connected to the end of the first placement section opposite to the arc plasma generation space, and in which the organic fertilizer is placed, and the arc plasma generator is configured to stop generating the arc plasma when the second placement section is filled with modified nitrogen.

[0033] According to the present invention, it is possible to provide a novel technology that can significantly increase the nitrogen content of organic materials compared to conventional methods.

[0034] Figure 1 is a schematic side view showing the interior of a nitrogen-enhanced organic material manufacturing apparatus according to a preferred embodiment of the present invention. Figure 2 is a schematic overall configuration diagram showing a nitrogen-enhanced organic material manufacturing apparatus according to another preferred embodiment of the present invention. Figure 3 is a schematic side view showing the interior of the main body of the manufacturing apparatus shown in Figure 2. Figure 4 is a substantially perspective view showing the main body of the manufacturing apparatus shown in Figure 2 with the conduits removed. Figure 5 is a graph showing the energy consumption per unit amount of nitrogen fixed in leaf mold after the first irradiation in Experiment Example 1 using the manufacturing apparatus shown in Figure 1. Figure 6 is a graph showing the energy consumption per unit amount of nitrogen fixed in leaf mold after the second irradiation in Experiment Example 1 using the manufacturing apparatus shown in Figure 1. Figure 7 is a graph showing the amount of nitrogen fixed in the leaf mold in the first and second configurations in Experiment Example 1 using the manufacturing apparatus shown in Figure 1. Figure 8 is a graph showing the energy consumption per unit nitrogen fixation amount in the leaf mold in the first and second placement areas in Experiment Example 1 using the manufacturing apparatus shown in Figure 1. Figure 9 is a graph showing the amount of nitrogen fixation per unit nitrogen fixation for each residence time of the second gas in the plastic bag, which is the second placement area, in Experiment Example 2 using the manufacturing apparatus shown in Figure 1. Figure 10 is a graph showing the energy consumption per unit nitrogen fixation amount per unit nitrogen fixation for each residence time of the second gas in the plastic bag, which is the second placement area, in Experiment Example 2 using the manufacturing apparatus shown in Figure 1. Figure 11 is a graph showing the amount of nitrogen fixation per unit time for each residence time of the second gas in the plastic bag, which is the second placement area, in Experiment Example 2 using the manufacturing apparatus shown in Figure 1. Figure 12 is a graph showing the processing rate of the leaf mold for each residence time of the second gas in the plastic bag, which is the second placement area, in Experiment Example 2 using the manufacturing apparatus shown in Figure 1. Figure 13 is a graph showing the flow rate of the second gas and the nitrogen oxide concentration in the second gas at the position just before the second gas reaches the second placement section in Experiment Example 3 using the manufacturing apparatus shown in Figure 2. Figure 14 is a graph showing the relationship between the flow rate of the second gas and the nitrogen fixation rate in water at the position just before the second gas reaches the second placement section in Experiment Example 3 using the manufacturing apparatus shown in Figure 2.FIG. 15 is a graph showing the relationship between the flow rate of the second gas at a position immediately before the second gas reaches the second placement section and the energy consumption during nitrogen fixation with respect to water in Experimental Example 3 using the manufacturing apparatus shown in FIG. 2. FIG. 16 is a graph showing the relationship between the flow rate of the second gas at a position immediately before the second gas reaches the second placement section and the energy consumption during nitrogen fixation with respect to leaf mold in Experimental Example 3 using the manufacturing apparatus shown in FIG. 2. FIG. 17 is a graph showing the relationship between the flow rate of the second gas at a position immediately before the second gas reaches the second placement section and the energy consumption in Experimental Example 3 using the manufacturing apparatus shown in FIG. 2. FIG. 18 is an image showing Komatsuna cultivated with leaf mold nitrogen-fixed using the manufacturing apparatus shown in FIG. 2 in Experimental Example 4. FIG. 19 is a graph showing the nitrogen concentration in the dried state of nitrogen-fixed bamboo bagasse in Experimental Example 5 using the manufacturing apparatus shown in FIG. 2. FIG. 20 is a graph showing the energy consumption per unit nitrogen fixation amount during nitrogen fixation to bamboo bagasse in Experimental Example 5 using the manufacturing apparatus shown in FIG. 2.

[0035] In this specification, the term "comprise" means that other components may be included in addition to the target component. The term "consist of" means that no other components are included in addition to the target component. In this specification, when described as "comprise", it includes the "consist of" aspect and the "consist essentially of" aspect. The term "consist essentially of" means that other components are not included in a manner that exhibits a special function (such as a manner that completely loses the effects of the invention).

[0036] Also, in this specification, the numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value.

[0037] Hereinafter, with reference to the drawings as appropriate, a manufacturing apparatus for an organic material with enhanced nitrogen content, a manufacturing method for an organic material with enhanced nitrogen content, a plant cultivation method, and a soil improvement method according to preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In all the following drawings, for ease of viewing the drawings, the dimensions, ratios, etc. of each component are appropriately different.

[0038] [Manufacturing Apparatus for Organic Material with Enhanced Nitrogen Content] FIG. 1 is a schematic side view showing the interior of a manufacturing apparatus for an organic material with enhanced nitrogen content according to a preferred embodiment of the present invention. As shown in FIG. 1, the manufacturing apparatus 1 of the present embodiment has an arc plasma generation space 2a, an arc plasma generation unit 2 that generates arc plasma in the arc plasma generation space 2a, a power source 6 that supplies power to the arc plasma generation unit 2, a first gas supply unit 3 that supplies a first gas containing nitrogen (N ２ ) and oxygen (O ２ ) to the arc plasma generation space 2a, a water addition unit 4 that adds water to the first gas, an organic material placement unit 5 where the solid organic material 10 is placed, and a cooling water circulation mechanism 9 to be described later.

[0039] The arc plasma generation unit 2 includes an anode 2b and a cathode 2c and is composed of a quartz tube. The inner diameter of the quartz tube was 58 mm and the length was 300 mm. Hereinafter, for the convenience of explaining the manufacturing apparatus 1, the side of the anode 2b with respect to the cathode 2c will be described as "down" and the opposite side as "up". The anode 2b is supported by a scaffold material 11 on the left side of the drawing and a scaffold material 12 on the right side of the drawing. The scaffold material 12 has a lower part 12a formed of an insulator, and an upper part 12b also serves as a current path from the power source 6 to the anode 2b.

[0040] The above-mentioned arc plasma generation space 2a is the space between the cathode 2c and the anode 2b where arc plasma is generated due to the voltage difference applied between the cathode 2c and the anode 2b, and is surrounded by the cathode 2c and the anode 2b. By performing arc discharge in the arc plasma generation space 2a, nitrogen and oxygen contained in the first gas become plasma. In this specification, "plasma" means a group of charged particles in which molecules constituting a gas are separated into positive (cations) and negative (electrons) by ionization, and is a collective of particles (ionized gas) that is electrically almost neutral as a whole. Also, in this specification, the plasma obtained by arc discharge is also referred to as "arc plasma", and the process of converting a gas into plasma by arc discharge is also referred to as "arc plasma conversion". The arc plasma generation unit 2 of the present embodiment includes one anode 2b and one cathode 2c, but the number of the anode 2b and the cathode 2c may each be 2 or more. The materials of the anode 2b and the cathode 2c are not particularly limited, and examples thereof include oxygen-free copper, tungsten, copper alloys, and the like. A tungsten wire (not shown) for efficiently emitting electrons is provided near the cathode 2c.

[0041] The anode 2b is in a ring shape and is arranged with the hole in the middle facing in the vertical direction. Since the first gas is supplied downward from a position near the cathode 2c toward the arc plasma generation space 2a by the first gas supply unit 3 described later, the gas converted into arc plasma in the arc plasma generation unit 2 jets downward in the state of the plasma jet flow 8 through the above hole of the anode 2b. Thus, the anode 2b serves as a nozzle (plasma jet ejection unit) for ejecting the plasma jet flow 8.

[0042] The first gas to be converted into arc plasma contains nitrogen molecules (N ２ ) and oxygen molecules (O ２ ). Therefore, by converting the first gas into arc plasma in the arc plasma generation unit 2, it dissociates into two nitrogen atoms and two oxygen atoms. Then, during and after the ejection as the plasma jet flow 8, the nitrogen atoms and oxygen atoms combine during the process of temperature decrease, and nitric oxide (NO) is generated. Also, a part of it is NO ２ , NO ３, N ２ Other NOx, such as oxygen, is also generated. A second gas containing at least one of these nitrogen oxides is supplied to the organic material placement section 5 and comes into contact with the organic material 10 placed in the organic material placement section 5, thereby increasing the nitrogen content of the organic material 10.

[0043] By converting a first gas containing nitrogen and oxygen into an arc plasma using an arc discharge, the nitrogen content of the organic material 10 can be increased more effectively than in conventional methods. Although it is not necessarily required to eject the arc plasma-converted gas as a plasma jet 8, ejecting the arc plasma-converted gas as a plasma jet 8 allows for the efficient generation of active species such as nitric oxide.

[0044] The type of nitrogen content enhanced by the organic material 10 is not particularly limited, but the enhanced nitrogen content may include, for example, at least one selected from the group consisting of ammonia, nitrate, nitrite, urea, and their ions.

[0045] The nitrogen-enhanced organic material 10 may contain, for example, 1.1 times, 2 times, 5 times, or 10 times the molar concentration of nitrate and nitrate ions compared to the untreated organic material 10. Furthermore, the nitrogen-enhanced organic material 10 may contain, for example, 1.1 times, 2 times, 5 times, or 10 times the molar concentration of nitrite and nitrite ions compared to the untreated organic material 10.

[0046] The distance L1 between the anode 2b and the cathode 2c is not particularly limited, but in the manufacturing apparatus 1, it is set to 230 mm.

[0047] The arc plasma generation unit 2 of this embodiment is configured as an arc thermal plasma torch. In this specification, "arc thermal plasma torch" means a torch that generates high heat in the arc plasma generation space 2a when generating plasma by arc discharge. The specific temperature of the high heat is not particularly limited, but for example, it can be 5,000°C or higher, or 10,000°C or higher. Furthermore, the arc plasma generation unit 2 is a non-transition type DC arc, and does not pass current between the organic material 10 and the electrodes, but generates an arc discharge by passing a DC current between the anode 2b and the cathode 2c.

[0048] As shown by the bold arrows in Figure 1 indicating the flow of cooling water, the manufacturing apparatus 1 has a cooling water circulation mechanism 9 as a cooling mechanism for electrodes 2b and 2c. The circulation mechanism 9 includes a cooling pipe 14 that transports cooling water 13 at a position horizontally outside the arc plasma generation space 2a. This prevents damage to electrodes 2b, 2c and their surroundings due to excessive heating. The same applies to the first arrangement section 5a, which will be described in detail later.

[0049] In addition, as described above, the manufacturing apparatus 1 is equipped with a cooling water circulation mechanism 9 near the arc plasma generation space 2a, so that the first gas is temporarily cooled at least 10 times before the gas that has been turned into arc plasma is supplied to the organic material placement section 5 as the second gas. ３ It can be cooled at a high speed of K (Kelvin) / s (seconds) or more. Here, the arc plasma of the first gas obtained by arc discharge is at a very high temperature of about 10,000 to 15,000°C. After that, the temperature of the plasmaized gas decreases, but if the rate of temperature decrease is low, the phenomenon occurs in which the obtained nitric oxide reverts back to nitrogen and oxygen. For this reason, the plasmaized gas is cooled by the cooling mechanism to 10 ３ By rapidly cooling at a speed of K / s or higher, the amount of nitric oxide can be maintained, and the amount of nitrogen oxides supplied to the organic material placement section 5 can be increased.

[0050] In this embodiment, the power supply 6 that supplies power to the arc plasma generation unit 2 is configured as a steady-state DC power supply. However, the power supply 6 may also be configured as an AC power supply.

[0051] The current value of the arc discharge (current value from power supply 6) is not particularly limited as long as it can generate an arc discharge, but may be, for example, 1 to 100 A, 5 to 50 A, or 8 to 15 A. In this embodiment, it is set to 10 A (amperes). Similarly, the voltage applied between the anode 2b and cathode 2c (voltage from power supply 6) is not particularly limited as long as it can generate an arc discharge, but is preferably 100 to 1000 V, and more preferably 300 to 500 V.

[0052] While there are no particular limitations on the time required to generate the arc plasma, from the viewpoint of reducing power consumption, it is preferable that it be 10 minutes or less, more preferably 5 minutes or less, and even more preferably 3 minutes or less.

[0053] The type of the first gas is not particularly limited as long as it includes nitrogen and oxygen. The first gas may be, for example, air, a mixture of nitrogen and oxygen gases, or it may contain other gas molecules. The proportion of nitrogen in the nitrogen-oxygen mixture is preferably 70 to 90% by volume. The first gas supply unit 3 in this embodiment is configured to supply air as an example of the first gas.

[0054] The first gas supply unit 3 may be composed of known pressurizing means such as a vacuum pump, propeller fan, blower, or compressor, or it may be a cylinder containing one or more of the various gases that make up the first gas as described above.

[0055] The amount of first gas supplied from the first gas supply unit 3 is not particularly limited, but for example, it can be in the range of 0.1 to 100 L / min, preferably 1 to 50 L / min, more preferably 10 to 40 L / min, and may also be 10 to 30 L / min or 15 to 30 L / min. At high flow rates, the residence time of the gas is shortened, so the nitrous oxide concentration in the second gas can be maintained at a high level.

[0056] The first gas supply unit 3 in this embodiment is configured to allow adjustment of the supply amount of the first gas within the above range, and by adjusting the supply amount of the first gas (in other words, the gas flow rate), the flow rate of the second gas to the organic material placement unit 5 can be adjusted in the same way. That is, the first gas supply unit 3 is equipped with a gas flow rate adjustment mechanism for the first gas. The gas flow rate adjustment mechanism can be configured by a known flow path adjustment mechanism, such as a valve opening and closing mechanism. For example, if the gas flow rate adjustment mechanism is configured by a valve opening and closing mechanism, the flow rate can be adjusted by adjusting the cross-sectional area of ​​the flow path of the first gas (in other words, the degree to which the valve is open or closed).

[0057] The flow rate of the second gas is not particularly limited, but from the viewpoint of increasing the nitrogen fixation rate and / or reducing the energy consumption required for nitrogen fixation, it may be 4 L / m or more, 6 L / m or more, 7 L / m or more, 4 to 10 L / m, 5 to 9 L / m, or 7 to 9 L / m.

[0058] Furthermore, if the energy input per unit flow rate of gas is high, the high temperature range is maintained for a longer period, which increases the amount of nitric oxide produced. However, the amount remaining changes due to competition with the decomposition reaction of nitric oxide.

[0059] The first gas supplied from the first gas supply unit 3 is diluted with water by the water dilution unit 4, and then supplied into the arc plasma generation space 2a under the pressure of the air pumped from the first gas supply unit 3. The first gas supply unit 3 may be positioned between the water dilution unit 4 and the arc plasma generation unit 2 in the flow of the first gas so as to pump the air after it has been diluted with water by the water dilution unit 4.

[0060] The water supply unit 4 includes a tank 4a for storing water, a supply pipe 4b for supplying the first gas supplied from the first gas supply unit 3 into the water contained in the tank 4a, and a discharge pipe 4c for discharging the first gas supplied into the water from the tank 4a. Under the pressure of the air pumped from the first gas supply unit 3, the first gas is supplied to the arc plasma generation space 2a through the supply pipe 4b, the water, and the discharge pipe 4c. In other words, the first gas is supplied to the arc plasma generation space 2a after being diluted with water in the tank 4a.

[0061] In this way, by adding water (water vapor) to the first gas supplied to the arc plasma generation space 2a beforehand, hydroxyl radicals are generated by the subsequent arc plasma formation. Since these hydroxyl radicals act as an oxidation accelerator for nitric oxide, after irradiation as a plasma jet 8, nitric oxide is converted to NO ２ and / or NO ３ It can efficiently oxidize to that point. Therefore, it can suppress the situation where nitric oxide obtained by arc plasma formation reverts back to oxygen and nitrogen.

[0062] The type of water stored in tank 4a is not particularly limited, but may be distilled water, tap water, irrigation water, etc.

[0063] The organic material placement section 5, where the solid organic material 10 is placed, has a first placement section 5a that is relatively close to the arc plasma generation space 2a, and a second placement section 5b that is further from the arc plasma generation space 2a than the first placement section 5a. However, it is not necessarily required that the manufacturing apparatus 1 have multiple placement locations for the organic material 10 as the organic material placement section 5; it may have only the first placement section 5a, or only the second placement section 5b. The second placement section 5b is a container for housing the organic material 10.

[0064] With the organic material 10 contained in the second container section 5b, a second gas containing nitrogen oxides is supplied to the second container section 5b and the container is left to stand. This allows nitrogen oxides to efficiently adhere to the organic material 10, increasing its nitrogen content and reducing energy consumption used to increase the nitrogen content. At this time, the second container section 5b may be removed from the conduit 7 (described later) and left to stand in a sealed state, or it may be left to stand while connected to the conduit 7.

[0065] The standing time (residence time of the second gas in the container) is not particularly limited, but may be 5 seconds or more, 10 seconds or more, 30 seconds or more, 60 seconds or more, 80 seconds or more, 100 seconds or more, 3 minutes or more, 5 minutes or more, 10 minutes or more, 30 minutes or more, 1 hour or more, or 2 hours or more (lower limit of standing time).

[0066] Furthermore, the standing time may be, for example, 2 minutes or less, 5 minutes or less, 10 minutes or less, 30 minutes or less, 1 hour or less, 3 hours or less, or 5 hours or less (upper limit of standing time). The lower and upper limits of the standing time mentioned above can be combined arbitrarily.

[0067] The type of container is not particularly limited, but examples include resin bags (plastic bags), rigid resin containers such as containers, and flexible container bags. Resin bags are particularly suitable for use. Containers that can be sealed are preferred.

[0068] In addition to the opening 5b1 for filling with the second gas, the second arrangement section 5b, which is configured as a container, may also have an opening 5b2 for discharging the second gas.

[0069] The manufacturing apparatus 1 of this embodiment further includes a conduit 7 for transferring the second gas containing nitrogen oxides obtained by arc plasma generation to the second placement section 5b. The length of the conduit 7 is designed so that the temperature of the second gas drops to 50°C or below while it is being transferred through the conduit 7. In this way, by supplying the second gas to the second placement section 5b at a temperature of 50°C or below, excessive drying of the organic material 10 placed in the second placement section 5b can be prevented. As a result, the nitrogen oxides contained in the second gas can be dissolved into the moisture contained in the organic material 10, thereby enhancing the nitrogen content enhancement effect of the organic material 10.

[0070] In addition, by supplying the second gas to the second placement section 5b at a temperature of 50°C or lower, it is possible to prevent the death of beneficial microorganisms contained in the organic material 10.

[0071] As described above, from the viewpoint of improving the effect of nitrogen enhancement and protecting beneficial microorganisms, the temperature of the second gas supplied to the organic material placement section 5 is preferably 50°C or lower (in other words, cooled to 50°C or lower), more preferably 40°C or lower, and may also be 30°C or lower (upper limit of the second gas temperature).

[0072] Furthermore, as the transport distance of the second gas to the organic material placement section 5 increases, nitrogen oxides may dissolve into condensation water that may be present during transport, weakening the nitrogen-enhancing effect on the organic material 10. Therefore, it is preferable that the second gas be supplied to the organic material placement section 5 while maintaining a temperature of 20°C or higher, preferably 25°C or higher, and may also be supplied to the organic material placement section 5 while maintaining a temperature of 30°C or higher (lower limit of the second gas temperature). The upper and lower limits of the second gas temperature mentioned above can be combined arbitrarily.

[0073] Furthermore, from the viewpoint of lowering the supply temperature of the second gas, the organic material placement section 5 may be positioned at least 150 mm away from the visible tip 8a (lower end in this embodiment) of the plasma jet stream 8, at least 500 mm away from the second gas flow path, or at least 1000 mm away from the second gas flow path. In this case, the distance along the flow path from the lower end 8a of the plasma jet stream 8 to the organic material placement section 5 may be the shortest distance that can be taken along the flow path.

[0074] As described above, the organic material 10 needs to contain water in order to dissolve the nitrogen oxides contained in the second gas into the water. The water content of the organic material 10, which is the percentage of water contained in the organic material 10, is not particularly limited, but may be, for example, 0.1 to 80% by mass, 1 to 50% by mass, 5 to 50% by mass, 30 to 100% by mass, 30 to 80% by mass, or 35 to 100% by mass. Furthermore, the water content may be, for example, 15% by mass or more, 30% by mass or more, 35% by mass or more, 40% by mass or more, 50% by mass or more, or 60% by mass or more (lower limit of water content). Furthermore, the water content may be, for example, 90% by mass or less, 80% by mass or less, 70% by mass or less, 60% by mass or less, or 50% by mass or less (upper limit of water content). The lower and upper limits of the moisture content mentioned above can be combined in any way.

[0075] The type of organic material 10 is not particularly limited, but may include, for example, soil, coco peat, rice hulls, peat moss, or other organic growing media used in plant cultivation, or organic fertilizers. It is preferable to use organic material 10 that has a low nitrogen content compared to other nutrients (phosphorus, potassium).

[0076] Organic fertilizers refer to fertilizers made from organic matter. Examples of organic fertilizers include organic fertilizers and sludge compost specified in the official standards of the Fertilizer Control Law, special fertilizers made from organic matter specified in the Fertilizer Control Law, and fertilizers produced by farmers using organic materials such as agricultural waste and livestock waste as raw materials.Specific examples of organic fertilizers include, for example, fish fertilizers such as fish meal powder, fish scrap powder, dried fish fertilizer powder, and boiled fish residue; oilseed meals such as rapeseed oil meal and soybean oil meal; bone meal made by crushing the bones remaining after removing fat and gelatin from animal bones; dried microbial fertilizers; poultry manure fertilizers such as cow manure compost, pig manure compost, chicken manure compost, fermented chicken manure, and dried chicken manure; methane fermentation residue; plant-based composts such as rice husk compost, pruned branch compost, rice straw compost, bark compost, and leaf mold; sludge compost and food waste compost, but are not limited to these. "Leaf mold" refers to compost made from fallen leaves and branches. "Compost" refers to organic matter such as rice straw, fallen leaves, livestock manure, and food waste that has been decomposed by microorganisms.

[0077] The organic material 10 may include one or more selected from the group consisting of, for example, plant compost, leaf mold, bagasse, and livestock manure compost.

[0078] Figure 2 is a schematic overall diagram showing a manufacturing apparatus 1A for nitrogen-enhanced organic materials according to another preferred embodiment of the present invention. In the following description, components identical or equivalent to those in the manufacturing apparatus 1 shown in Figure 1 are denoted by the same reference numerals, and their descriptions are simplified or omitted.

[0079] As shown in Figure 2, the manufacturing apparatus 1A of this embodiment comprises a main body 15 for generating arc plasma, a power supply 6, a first gas supply unit 3, a flow meter 16, and an organic material placement unit 5 where solid organic material 10 is placed. The organic material placement unit 5 is configured as a container (for example, a plastic bag) in which the organic material and the second gas are contained or filled, similar to the second placement unit 5b of the embodiment shown in Figure 1.

[0080] Figure 3 is a schematic side view showing the inside of the main body 15 of the manufacturing apparatus 1A shown in Figure 2. Figure 4 is a substantially perspective view showing the manufacturing apparatus 1A shown in Figure 2 with the conduit 17 removed from the main body 15.

[0081] As shown in Figure 3, the apparatus body 15 comprises an arc plasma generation unit 2 having an arc plasma generation space 2a, a water addition unit 4 that adds water to the first gas supplied from the first gas supply unit 3, a conduit 17 that transfers the gas ejected in the form of a plasma jet stream 8 from a nozzle (anode 2b) that functions as a plasma jet ejection unit of the arc plasma generation unit 2 to the organic material placement unit 5 as a second gas, a cooling pipe 19 that cools the conduit 17 and the ejected gas, and a support base 18 that supports these components.

[0082] The arc plasma generation unit 2 of this embodiment is also configured as an arc thermal plasma torch.

[0083] In this embodiment, the water addition unit 4 is located below the arc plasma generation unit 2. The first gas supplied from the first gas supply unit 3 is supplied from below into the tank 4a, water (water vapor) is added, and then it is converted into an arc plasma in the arc plasma generation space 2a. After that, the gas is injected in the form of a plasma jet stream 8 and transported through the conduit 17, and supplied to the organic material placement unit 5 as a second gas containing nitrogen oxides. Furthermore, since water is contained in the tank 4a of the water addition unit 4, the electrodes 2b and 2c can be cooled. Thus, in the manufacturing apparatus 1A according to this embodiment, the water addition unit 4 also serves as a cooling mechanism for the electrodes 2b and 2c.

[0084] In this embodiment, the first gas supply unit 3 is configured to adjust the supply amount of the first gas (and consequently the flow rate of the second gas) within a range of 2 to 10 L, but the supply amount of the first gas is not limited to this range.

[0085] The conduit 17 comprises a metal upstream conduit 17a, a downstream conduit 17b with one end (the lower end in Figure 3) connected to the organic material placement section 5, and a relay pipe 17c connecting the upstream conduit 17a and the downstream conduit 17b. However, the conduit 17 may consist of a single pipe, two pipes, or four or more pipes. In this embodiment, the downstream conduit 17b is made of polytetrafluoroethylene tubing, and the upstream conduit 17a is made of brass, but the material of the conduit 17 is not particularly limited.

[0086] The cooling pipe 19 transports the cooled cooling water. The cooling pipe 19 surrounds the conduit 17 (in other words, it is wrapped around the conduit 17). From the viewpoint of improving thermal conductivity, it is preferable that at least a portion of the conduit 17 and the cooling pipe 19 (especially the upstream portion in the gas flow path) is made of metal.

[0087] In this way, by forming at least a portion of the conduit 17 and the cooling pipe 19 from metal, and by wrapping the cooling pipe 19 around the conduit 17 that transports the gas ejected in the state of a plasma jet 8, the gas ejected as a plasma jet 8 and after ejection is at least temporarily supplied to the organic material placement section 5 as a second gas, 10 ３ High-speed cooling is possible at a rate of K (Kelvin) / s or higher. The cooling tube 19 in this embodiment is made of copper, but is not limited to this.

[0088] The maximum cooling temperature range per second is preferably 10 ４ It is K / s or higher, and more preferably 10 ５ The pressure is K / s or higher. By rapidly cooling the ejected gas, the amount of nitric oxide can be maintained, and the amount of nitrogen oxides supplied to the organic material placement section 5 can be increased.

[0089] Furthermore, the length of the downstream conduit 17b is set such that the gas ejected in the plasma jet 8 state cools to a temperature of 50°C or less within the downstream conduit 17b. As a result, a second gas at a temperature of 50°C or less is supplied to the organic material placement section 5, thereby preventing drying and the death of beneficial microorganisms. The temperature of the second gas supplied to the organic material placement section 5 is as detailed in the embodiment shown in Figure 1.

[0090] As described above, the gas ejected in the plasma jet stream 8 may come into contact with condensation water and be lost while being transported through the conduit 17. For this reason, it is preferable to design the conduit 17 to be as short as possible while lowering the temperature of the second gas to the above temperature range. The conduit 17 may also be equipped with a drying mechanism to dry the condensation water inside. An example of a drying mechanism is a mechanism that supplies air or heated air into the conduit 17.

[0091] The organic material 10 produced by the manufacturing apparatus of each of the above embodiments can be used in ways such as spreading it on a field or mixing it with the soil in the field, but is not limited to these uses.

[0092] [Method for producing an organic material with enhanced nitrogen content] Another preferred embodiment of the present invention provides a method for producing an organic material 10 with enhanced nitrogen content, comprising the steps of (A) generating an arc plasma from a first gas containing nitrogen and oxygen by arc discharge to obtain a second gas containing nitrogen oxides, and (B) supplying the second gas to a solid organic material 10. The nitrogen content of the organic material can be enhanced by the contact of the second gas containing nitrogen oxides with the solid organic material 10.

[0093] In the manufacturing method of this embodiment, since the first gas containing nitrogen and oxygen is converted into an arc plasma by arc discharge, the second gas can be enriched with a high concentration of nitrogen oxides, and the nitrogen content of the organic material 10 can be significantly increased compared to conventional methods.

[0094] The type of organic material 10 is not particularly limited, but for example, the organic material 10 detailed in the embodiment shown in Figure 1 can be cited. The same applies to the moisture content of the organic material 10.

[0095] The type of nitrogen content enhanced by the manufacturing method of this embodiment is not particularly limited, but the enhanced nitrogen content may include, for example, at least one selected from the group consisting of ammonia, nitrate, nitrite, urea, and their ions. The enhanced amounts of nitrate and nitrate ions, and nitrite and nitrite ions contained in the organic material 10 are as detailed in the embodiment of Figure 1 in terms of molar concentration.

[0096] The apparatus used to carry out the above steps (A) and (B) is not particularly limited, but for example, each apparatus 1 or 1A shown in Figures 1 to 4 can be suitably used. Steps (A) and (B) can be carried out by the methods detailed in each embodiment shown in Figures 1 to 4 above, but each step will be described below.

[0097] In step (A), preferably, the first gas is converted into an arc plasma and ejected in the form of a plasma jet. During and after the ejection, the temperature of the arc plasma gas decreases. During this time, nitrogen oxides such as nitric oxide are generated, and a second gas containing nitrogen oxides is obtained.

[0098] Step (A) involves temporarily 10 times the arc plasma gas before it is supplied to the organic material as the second gas. ３ It is preferable to include a step of high-speed cooling at a rate of K (Kelvin) / s (seconds) or higher. Examples of cooling rates during high-speed cooling include the rates detailed in each embodiment of Figures 1 to 4.

[0099] On the other hand, in process (B), it is preferable to supply the second gas, which has been converted into an arc plasma and ejected as a plasma jet, to the organic material 10 after it has cooled to a temperature of 50°C or lower. This prevents excessive drying of the organic material 10 and the death of beneficial microorganisms. The temperature of the second gas when supplied to the organic material 10 is as described above.

[0100] In step (B), it is preferable to supply a second gas into a container containing the organic material 10 and allow the container to stand for 100 seconds or more once the second gas has filled it. The standing method and standing time are described in detail in each embodiment of Figures 1 to 4. The container is the same as the container described in detail in each embodiment of Figures 1 to 4. Here, it is preferable to stop the generation of arc discharge in step (A) and the generation of arc plasma when the container is filled with the second gas. This makes it possible to reduce energy consumption.

[0101] A method for producing an organic material with enhanced nitrogen content preferably includes, in addition to steps (A) and (B), a step (C) prior to step (A), in which a first gas is passed through water to add water to the first gas (more specifically, steam is added). Including step (C) in the production method allows for further oxidation and stabilization of the generated nitric oxide, as described above.

[0102] [Method for cultivating plants] A method for cultivating plants according to yet another preferred embodiment of the present invention includes the steps of: producing a nitrogen-enhanced solid organic material 10 by the manufacturing method described above; and cultivating plants in soil to which the nitrogen-enhanced solid organic material 10 has been applied. The soil to which the organic material 10 is applied is not particularly limited. The soil may be a paddy field, a field, an orchard, or horticultural soil. The method of application is not particularly limited and can be carried out in the same way as ordinary organic materials, for example, by mixing it into the soil or by sprinkling it on the soil surface. The timing of application of the organic material 10 is also not particularly limited. It can be applied as appropriate depending on the type of plant, its growth stage, the condition of the soil, etc.

[0103] The plants grown in soil treated with organic fertilizer are not particularly limited. They should be selected appropriately depending on the type of soil. Examples of plants include, but are not limited to, grains, vegetables, fruit trees, and flowers. Plants can be cultivated using known methods, depending on the type of plant.

[0104] In this embodiment of plant cultivation methods, plants are grown using organic materials with enhanced nitrogen content, resulting in good plant growth. Furthermore, since no chemical fertilizers are used, it can be applied to organic farming.

[0105] [Soil Improvement Method] A soil improvement method according to yet another preferred embodiment of the present invention includes the steps of: producing a nitrogen-enhanced solid organic material 10 by a manufacturing method according to the embodiment of [Method for Manufacturing Nitrogen-Enhanced Organic Material], and applying the nitrogen-enhanced solid organic material 10 to the soil (D).

[0106] The soil to which the organic material 10 is applied in step (D) is not particularly limited as long as it is soil used for plant cultivation, but it may be, for example, a paddy field, a field, an orchard, or horticultural soil. The application method can be the same as for ordinary organic materials, for example, it may be mixed into the soil or spread on the soil surface.

[0107] In the soil improvement method of this embodiment, since an organic material 10 with enhanced nitrogen content is used, an appropriate amount of nitrogen can be supplied to the soil together with other nutrients contained in the organic material 10. Therefore, soil that is suitable for plant growth can be prepared.

[0108] The present invention is not limited to the embodiments described above, and it goes without saying that various modifications are possible within the scope of the invention as described in the claims, and these modifications are also included within the scope of the present invention.

[0109] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0110] [Experimental Example 1] In this experiment, using the manufacturing apparatus 1 shown in Figure 1, 2 kg of leaf mold was placed in both the first placement section 5a and the second placement section 5b, and air was supplied as the first gas to evaluate the nitrogen enhancement effect by arc discharge. The moisture content of the leaf mold before plasma irradiation was 30-40%. Calculating from the position of the lower end portion 8a (see Figure 1), which is the visible tip of the plasma jet stream, the first placement section 5a was located at a distance of 150 mm from the second gas flow path, and the second placement section 5b was located at a distance of 1000 mm from the second gas flow path.

[0111] <Materials and Methods> The irradiation (arc discharge) conditions were as follows: Discharge power: 3.7W Current: 10A Irradiation target: Leaf mold Irradiation time: 2 minutes, 5 minutes Gas flow rate: 30L / min

[0112] As an experimental area for the opening conditions of the second arrangement section 5b, leaf mold was placed in a 70L plastic bag (an example of the second arrangement section 5b), and an opening 5b1 for filling with the second gas and an opening 5b2 for discharging the second gas were made in the plastic bag. A conduit 7 was connected to opening 5b1 to create a system. The supply time of the second gas by arc discharge was set to 5 minutes.

[0113] As a semi-sealed experimental section of the second configuration area 5b, leaf mold was placed in a 70L plastic bag (an example of the second configuration area 5b), and a conduit 7 was connected to the plastic bag with only an opening 5b1 for filling with the second gas. When the plastic bag expanded with the second gas, the opening 5b2 was opened to create a system. The supply time of the second gas by arc discharge was set to 5 minutes.

[0114] As a sealed experimental section of the second arrangement 5b, leaf mold was placed in a 70L plastic bag (an example of the second arrangement 5b), and a conduit 7 was connected to the plastic bag with only an opening 5b1 for filling it with the second gas. When the plastic bag inflated with the second gas, the opening 5b1 was closed. The supply time of the second gas by arc discharge was set to 2 minutes.

[0115] The second gas supplied to the first configuration section 5a was above 50°C. The second gas supplied to the second configuration section 5b was between 40 and 50°C. The same was true for each experimental example from Experimental Example 2 onward.

[0116] (Nitrate Ion Concentration Measurement) 5 g of leaf mold sample was mixed with 20 mL of ultrapure water and 0.1 g of CaSO4, and the extract was obtained by stirring and filtering for 10 minutes. Subsequently, the nitrate ion concentration in the leaf mold was measured by a colorimetric method (reagent: Tongrentang; NO2 / NO3 assay kit-C II). Specifically, after incubation with enzymes for 2 hours, the reagent was added and allowed to stand for 10 minutes, and the concentration was measured from the degree of color development.

[0117] <Results> Figure 5 is a graph showing the energy consumption per unit amount of nitrogen fixed in leaf mold after the first irradiation of Experiment Example 1 using the manufacturing apparatus shown in Figure 1. Figure 6 is a graph showing the energy consumption per unit amount of nitrogen fixed in leaf mold after the second irradiation of Experiment Example 1 using the manufacturing apparatus shown in Figure 1. In Figure 5, "Inside" shows the energy consumption per unit amount of nitrogen fixed in leaf mold placed in the first placement section 5a, while the other systems show the energy consumption in the second placement section 5b. The second system (element) and the fourth system from the left in Figure 5 were under the same open conditions.

[0118] As shown in Figure 5, the energy consumption per unit amount of nitrogen fixed was very high in the first configuration section 5a, while it was suppressed in the second configuration section 5b. Furthermore, as shown in Figures 5 and 6, the energy consumption per unit amount of nitrogen fixed was suppressed in the second configuration section 5b, especially under semi-sealed or sealed conditions.

[0119] These results suggest that under open conditions, nitrogen fixation efficiency varies; under semi-sealed conditions, stable and high nitrogen fixation efficiency (31-33 MJ / mol) can be achieved; and under sealed conditions, all nitrogen in the plastic bag was fixed, resulting in approximately 15% lower energy consumption compared to semi-sealed conditions.

[0120] Figure 7 is a graph showing the amount of nitrogen fixed in the leaf mold in the first placement section 5a and the leaf mold in the second placement section 5b in Experiment Example 1 using the manufacturing apparatus shown in Figure 1. Figure 8 is a graph showing the energy consumption per unit amount of nitrogen fixed in the leaf mold in the first placement section 5a and the leaf mold in the second placement section 5b in Experiment Example 1 using the manufacturing apparatus shown in Figure 1.

[0121] As shown in Figures 7 and 8, the second configuration 5b, which is further from the arc plasma generation space, fixed more nitrogen than the first configuration 5a, which is closer to the arc plasma generation space, and consequently consumed less energy. This result suggests that if the distance from the arc plasma generation space to the organic material is too short, the nitrogen fixation efficiency decreases.

[0122] [Experimental Example 2] In this experiment, using the manufacturing apparatus 1 shown in Figure 1, air was supplied as the first gas, and the conditions for the duration of retention of the second gas in the plastic bag, which is the second placement section 5b, were investigated. The irradiation conditions were the same as in Experimental Example 1, except that the irradiation time was set to 3 minutes. The opening 5b2 was kept closed. Specifically, two experimental sections were set up: one in which the second gas was retained in a plastic bag containing organic material for 10 seconds, and another in which the second gas was retained for 100 seconds.

[0123] Figure 9 is a graph showing the amount of nitrogen fixed per unit nitrogen fixed in the plastic bag, which is the second placement section 5b, for each residence time in Experimental Example 2 using the manufacturing apparatus shown in Figure 1. Figure 10 is a graph showing the energy consumption per unit nitrogen fixed amount per unit residence time in the plastic bag, which is the second placement section 5b, for each residence time in Experimental Example 2 using the manufacturing apparatus shown in Figure 1.

[0124] As shown in Figure 9, when the residence time of the second gas in the plastic bag was 10 seconds, the amount of nitrogen fixed was about 5 mmol, while when the residence time was 100 seconds, it increased to about 35 mmol. As a result, the energy consumption was about 30 MJ / mol-N. Under the condition of a residence time of 100 seconds, 0.8% of the second gas and about 15% of the generated nitric oxide were fixed in the leaf mold.

[0125] These results suggest that extending the residence time of the second gas in the container can significantly increase the amount of nitrogen fixed.

[0126] Figure 11 is a graph showing the amount of nitrogen fixed per unit time for each residence time of the second gas in the plastic bag, which is the second placement section 5b, in Experiment Example 2 using the manufacturing apparatus shown in Figure 1. Figure 12 is a graph showing the processing rate of leaf mold for each residence time of the second gas in the plastic bag, which is the second placement section 5b, in Experiment Example 2 using the manufacturing apparatus shown in Figure 1. Figure 12 shows the amount of leaf mold processed per hour when irradiation treatment is performed until the nitrogen concentration reaches 0.1 mass%, which is the nitrogen concentration at which a plant growth promoting effect was observed in a separate field experiment.

[0127] As shown in Figures 11 and 12, extending the residence time of the second gas in the container increased the amount of nitrogen fixed per unit time and the processing rate of the leaf mold.

[0128] [Experimental Example 3] In this experiment, using the manufacturing apparatus 1A shown in Figure 2, air was supplied as the first gas to perform nitrogen fixation on humus or water placed in the organic material placement section 5. The irradiation conditions were as follows: Power supply: DC 100V, approximately 6A. Compressed air was supplied at 2 to 10 L / min.

[0129] Figure 13 is a graph showing the flow rate of the second gas (specifically, the unit energy input (SEI) during nitrogen fixation) and the concentration of nitrogen oxides (NOx) in the second gas (exhaust gas) (in other words, the proportion of nitrogen oxides) at the position just before the second gas reaches the second placement section 5b in Experimental Example 3 using the manufacturing apparatus shown in Figure 2. The concentration of nitrogen oxides was quantified using FTIR (Fourier Transform Infrared Spectroscopy) and a detector tube.

[0130] As shown in Figure 13, it became clear that the concentration of nitrogen oxides in the second gas increases as the flow rate of the second gas increases, and then plateaus at around 3%.

[0131] Figure 14 is a graph showing the relationship between the flow rate of the second gas at the position just before it reaches the second placement section 5b and the nitrogen fixation rate in water in Experiment Example 3 using the manufacturing apparatus shown in Figure 2. Figure 14 shows data obtained when 0.5 L of ultrapure water was treated and nitrate nitrogen and nitrite nitrogen were detected.

[0132] As shown in Figure 14, it was suggested that the nitrogen fixation rate increases as the gas flow rate of the second gas increases.

[0133] Figure 15 is a graph showing the relationship between the flow rate of the second gas at the position just before it reaches the second placement section 5b and the energy consumption during nitrogen fixation in water, in Experiment Example 3 using the manufacturing apparatus shown in Figure 2. Figure 15 shows data obtained when 0.5 L of ultrapure water was treated and nitrate nitrogen and nitrite nitrogen were detected.

[0134] As shown in Figure 15, a V-shaped curve was formed in the relationship between the flow rate of the second gas and energy consumption. This result suggests that there may be an optimal value for the flow rate of the second gas when the objective is to reduce energy consumption.

[0135] Figure 16 is a graph showing the relationship between the flow rate of the second gas at the position just before it reaches the second placement section 5b and the energy consumption during nitrogen fixation in the leaf mold in Experiment Example 3 using the manufacturing apparatus shown in Figure 2. Figure 16 shows data obtained by processing 1 kg of leaf mold and detecting nitrate nitrogen and nitrite nitrogen.

[0136] As shown in Figure 16, it was suggested that even in the case of leaf mold, there may be a range of gas flow rates that can reduce energy consumption.

[0137] Figure 17 is a graph showing the relationship between the flow rate of the second gas (specifically, the unit energy input (SEI) during nitrogen fixation) and energy consumption at the position just before the second gas reaches the second placement section 5b in Experiment Example 3 using the manufacturing apparatus shown in Figure 2. Figure 17 shows data obtained by processing 1 kg of leaf mold and detecting nitrate nitrogen and nitrite nitrogen.

[0138] As shown in Figure 17, it was suggested that there may be an optimal value for the unit energy input, i.e., the ratio of organic materials, in order to reduce energy consumption.

[0139] [Experimental Example 4] In this experiment, during the winter, leaf mold that had undergone nitrogen fixation in Experimental Example 3 was placed in Jiffy Pots, komatsuna seeds were sown and cultivated for two weeks, then transplanted to larger pots and cultivated for 30 to 40 days from sowing. Two types of leaf mold were prepared: one that had been irradiated with arc plasma for 10 minutes and another that had been irradiated with arc plasma for 30 minutes. When transplanting to larger pots, the leaf mold inside the Jiffy Pot was left as is, and potting soil was placed on the outside. For comparison, a system using unirradiated leaf mold was also prepared separately.

[0140] Figure 18 shows images of komatsuna (Japanese mustard spinach) grown in nitrogen-fixed leaf mold using the manufacturing apparatus 1A shown in Figure 2, in Experimental Example 4. The left side of Figure 18 shows an image of komatsuna viewed from above, and the right side shows an image of komatsuna viewed from diagonally above. As shown in Figure 18, 30 minutes of arc plasma irradiation resulted in a higher nitrogen content and better growth of komatsuna than 10 minutes of arc plasma irradiation. In the unirradiated system, the leaf mold contained almost no nitrogen, and therefore almost no komatsuna grew.

[0141] [Experimental Example 5] In this experiment, the nitrate nitrogen concentration and energy consumption for nitrogen fixation were evaluated for several bamboo bagasse systems with different moisture contents using the production apparatus 1A shown in Figure 2. The experimental conditions for each system were as follows: Run 1: Mixture of 200 g bamboo bagasse and 100 g water (moisture content 34-40%) Run 2: Mixture of 150 g bamboo bagasse and 150 g water (moisture content 50-55%) Run 3: Mixture of 100 g bamboo bagasse and 200 g water (moisture content 67-72%) In all systems, the flow rates of the first gas (air) and second gas were 5 L / min, the irradiation time was 10 minutes, and the power was 0.7 kW. After irradiation, nitrogen components were extracted from the bamboo bagasse of each system using an aqueous potassium chloride solution, and the nitrogen concentration was measured and then converted to the nitrogen concentration in the dry state of the bamboo bagasse.

[0142] Figure 19 is a graph showing the nitrogen concentration in the dried state of nitrogen-fixed bamboo bagasse in Experimental Example 5 using the manufacturing apparatus 1A shown in Figure 2. Figure 20 is a graph showing the energy consumption per unit amount of nitrogen fixed during nitrogen fixation in bamboo bagasse in Experimental Example 5 using the manufacturing apparatus 1A shown in Figure 2. In Figure 19, "Control" represents the nitrogen concentration in bamboo bagasse that has not been irradiated with plasma.

[0143] As shown in Figure 19, the nitrogen concentration increased as the moisture content of the bamboo bagasse increased. The nitrogen concentration was significantly higher in Run 3 compared to Run 1.

[0144] On the other hand, as shown in Figure 20, the effect of moisture content on nitrogen fixation efficiency was almost negligible, and energy consumption was comparable to that of leaf mold under all conditions.

[0145] These results suggest that by using arc discharge to create plasma from gases containing nitrogen and oxygen, nitrogen fixation can be achieved in bamboo bagasse with the same efficiency as in leaf mold, and that a significant increase in nitrogen content can be obtained regardless of the type of organic material.

[0146] According to the present invention, the nitrogen content can be significantly increased by arc discharge, making it suitable for industrial use.

[0147] 1...Manufacturing equipment, 1A...Manufacturing equipment, 2...Arc plasma generation unit, 2a...Arc plasma generation space, 2b...Anode, 2c...Cathode, 3...First gas supply unit, 4...Water addition unit, 4a...Tank, 4b...Supply pipe, 4c...Discharge pipe, 5...Organic material placement unit, 5a...First placement unit, 5b...Second placement unit, 5b1...Opening, 5b2...Opening, 6...Power supply, 7...Conduit, 8...Plasma jet stream, 9...Cooling water circulation mechanism, 10...Organic material, 11...Scaffolding material, 12...Scaffolding material, 12a...Lower part of scaffolding material, 12b...Upper part of scaffolding material, 13...Cooling water, 14...Cooling pipe, 15...Main unit, 16...Flow meter, 17...Conduit, 17a...Upstream conduit, 17b...Downstream conduit, 17c...Intermediate pipe, 18...Support base, 19...Cooling pipe, L1...Distance

Claims

1. A method for producing an organic material with enhanced nitrogen content, comprising the steps of: (A) generating an arc plasma from a first gas containing nitrogen and oxygen by arc discharge to obtain a second gas containing nitrogen oxides; and (B) supplying the second gas to a solid organic material.

2. The manufacturing method according to claim 1, wherein in step (A), the first gas is converted into an arc plasma and ejected in the form of a plasma jet, and in step (B), the ejected second gas is supplied to the organic material after being cooled to a temperature of 50°C or lower.

3. The above step (A) involves temporarily heating the arc plasma gas to 10 ３ The manufacturing method according to claim 2, comprising a step of high-speed cooling at a rate of K (Kelvin) / s or higher.

4. The manufacturing method according to claim 2, comprising the step of passing the first gas through water to add water to the first gas, prior to step (A).

5. The manufacturing method according to any one of claims 1 to 4, wherein the nitrogen content to be enhanced includes at least one selected from the group consisting of ammonia, nitrate, nitrite, urea, and ions thereof.

6. The manufacturing method according to any one of claims 1 to 4, wherein the organic material includes one or more selected from the group consisting of plant compost, leaf mold, bagasse, and livestock manure compost.

7. The manufacturing method according to any one of claims 1 to 4, wherein in step (B), the second gas is supplied into a container containing the organic material, and the container is left standing for 100 seconds or more with the second gas filling it.

8. A method for cultivating plants, comprising the steps of: producing a nitrogen-enriched solid organic material by a manufacturing method described in any one of claims 1 to 4; and cultivating plants in soil to which the nitrogen-enriched solid organic material has been applied.

9. A method for improving soil, comprising the steps of: producing a solid organic material with enhanced nitrogen content by a manufacturing method described in any one of claims 1 to 3; and applying the solid organic material with enhanced nitrogen content to soil.

10. A manufacturing apparatus for nitrogen-enhanced organic materials, comprising: an arc plasma generation unit having an arc plasma generation space surrounded by multiple electrodes, which generates arc plasma by arc discharge in the arc plasma generation space; a first gas supply unit which supplies a first gas containing nitrogen and oxygen to the arc plasma generation space; and an organic material placement unit where solid organic materials are placed, wherein a second gas containing nitrogen oxides obtained by arc plasmaization of the first gas in the arc plasma generation unit is supplied to the organic material placement unit.

11. The manufacturing apparatus according to claim 10, comprising: a plasma jet ejection unit that ejects gas that has been turned into arc plasma in the arc plasma generation unit in the form of a plasma jet stream; and a conduit for transferring the gas ejected from the plasma jet ejection unit to the organic material placement unit, wherein the gas ejected from the plasma jet ejection unit is cooled to a temperature of 50°C or less in the conduit before being supplied to the organic material placement unit.

12. The conduit is surrounded by a cooling pipe for transporting cooling water, and at least a portion of the conduit and the cooling pipe is made of metal, and the gas ejected from the plasma jet nozzle is at least temporarily 10 ３ The manufacturing apparatus according to claim 11, configured to enable high-speed cooling at a rate of K (Kelvin) / s or higher.

13. The manufacturing apparatus according to claim 11, comprising a tank for containing water, a water addition unit for adding water to the first gas in the tank, and configured such that the first gas, to which water has been added by the water addition unit, is supplied to the arc plasma generation space by a first gas supply unit.

14. The manufacturing apparatus according to claim 11, wherein the arc plasma generating unit is configured as an arc thermal plasma torch.

15. The manufacturing apparatus according to claim 11, wherein, within the organic material arrangement section, the organic material is arranged at least 150 mm away from the tip of the plasma jet stream through the second gas flow path.

16. The manufacturing apparatus according to claim 15, wherein, within the organic material arrangement section, the organic material is arranged at least 1,000 mm away from the tip of the plasma jet stream through the second gas flow path.

17. The manufacturing apparatus according to claim 11, wherein the organic material arrangement section is a container for containing the organic material and the second gas.

18. The manufacturing apparatus according to claim 14, further comprising a cooling mechanism for the plurality of electrodes and a gas flow rate adjustment mechanism, wherein the arc thermal plasma torch is a non-transition type DC arc.

Images