JP4857459B2 - Hydrothermal reaction method and apparatus - Google Patents

Description

【００４５】
【表２】

【００４６】
【表３】

【００４７】
【表４】

【００４８】
比較例１
実施例１の反応器の噴射機構の噴射ノズルを、９ｍｍの噴射口径を持つノズルに変更した。実施例１と同じ有機性廃薬物を用いて、水、空気とともに、超臨界状態で水熱酸化反応を行った。
被反応物供給量を０．１２ｋｇ／ｍｉｎ、水供給量を１．００ｋｇ／ｍｉｎ、空気供給量を２．２２ｋｇ／ｍｉｎと実施例１と同じ条件として水熱反応を開始したが、反応が継続せず、不完全燃焼で生成したチャーと思われる黒い物質を含む流体が排出された。
本比較例では、噴射口の内径は反応器内径の１／１２、噴射速度は１．７ｍ／ｓｅｃであり、被反応物と酸化剤を含む被処理流体が十分に混合されないために、反応熱による温度上昇と反応の進行、供給された被処理物の反応開始が満足に実現しなかったと判断される。
【図面の簡単な説明】
【図１】実施形態の水熱反応装置の断面図である。
【符号の説明】
１ 反応器
２ 噴射機構
３ 噴射口
４ 噴射ノズル
５ 混合部
６ 被反応物導入部
７ 酸化剤導入部
８ 被反応物供給路
９ 酸化剤供給路
１１ ライナー
１２ スクレーパ
１３ 駆動機構
１４ 冷却水路
１５ 反応物取出部
１６ 反応物取出路
２１ 完全混合域
２２ プラグフロー域
２３ 冷却域[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydrothermal reaction method and apparatus for performing waste decomposition, energy generation or chemical production, in particular, a hydrothermal reaction method suitable for conducting a hydrothermal reaction under supercritical or subcritical conditions of water and It relates to the device.
[0002]
[Prior art]
The hydrothermal reaction is a method of decomposing waste, generating energy, or producing a chemical substance by subjecting a reaction object to an oxidation reaction or hydrolysis reaction in a supercritical or subcritical state of water.
In recent years, in particular, water that causes an oxidation reaction by reacting a reactant containing an organic substance in a supercritical or subcritical state of water with an oxidant, and that completely decomposes the organic substance in the reactant in a short time. Thermal reactions are attracting attention.
[0003]
In this way, when the organic matter in the reaction product is oxidatively decomposed by hydrothermal reaction, the reaction product, oxidant, and water are in a supercritical state at a pressure of 22 MPa or higher at a temperature of 374 ° C. or higher, or 374 ° C. or higher. Reacts in a subcritical state at a pressure of 2.5 MPa or more and less than 22 MPa. In this case, it is not necessary to supply water when the reaction object contains an appropriate amount of water in advance.
As a result of the reaction, the organic substance is oxidatively decomposed to obtain a reaction product containing a high-temperature and high-pressure fluid composed of water and carbon dioxide, and a solid such as ash and salts in a dry or slurry state. The solid of the reaction product is separated by a solid separation device. The fluid from which the solid has been separated is recovered for energy, or cooled and decompressed, and separated into a gas component and a liquid component.
[0004]
As such a hydrothermal reaction method, an object to be decomposed such as an organic waste liquid to be decomposed and an oxidizing agent are pressurized with a high-pressure pump, mixed and injected from above into the reactor by an injection mechanism, and backflowed into the top of the reactor. There has been proposed a method in which a mixing compartment with a water vapor is formed and a plug flow compartment is formed in the lower part to perform a hydrothermal reaction (Japanese Patent Laid-Open No. 11-156186).
In the above method, a hydrothermal reaction can be performed efficiently by forming a mixing section with backflow at the upper part and a plug flow section at the lower part. It is requested.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to uniformly disperse the workpiece and the oxidant to be introduced into the reactor immediately after the introduction, thereby increasing the reaction efficiency and decomposing the reactant with high efficiency by a small apparatus. It is to provide a hydrothermal reaction method and apparatus capable of this.
[0006]
[Means for Solving the Problems]
The present invention is the following hydrothermal reaction method and apparatus.
(1) To a cylindrical reactor which is arranged substantially vertically and has a length not less than 6 times the inner diameter,
The mixture of the reactant and the oxidant is injected from the upper part of the reactor by an injection mechanism at an injection speed of 10 m / sec or more through an injection port having an inner diameter of 1/15 to 1/200 of the inner diameter of the reactor,
A hydrothermal reaction method characterized in that a substantially complete mixing zone and a plug flow zone are formed in the reactor thereby to perform a hydrothermal reaction in a supercritical or subcritical state of water.
(2) The method according to (1) above, wherein the reactant is a nitrogen-containing substance.
(3) a cylindrical reactor arranged in a substantially vertical direction for performing a hydrothermal reaction in a supercritical or subcritical state of water;
A reactant supply path for supplying the reactant to the upper part of the reactor;
An oxidant supply path for supplying an oxidant to the top of the reactor;
An injection mechanism for injecting the reactant supplied from the reactant supply path and the oxidant supplied from the oxidant supply path from the upper part of the reactor in a mixed state;
A reactant take-out path for taking out the reactant from the lower part of the reactor,
The reactor has a length of at least six times the inner diameter;
The injection mechanism is configured to inject a mixture of a reactant and an oxidant into the reactor at an injection speed of 10 m / sec or more from an injection port having an inner diameter of 1/15 to 1/200 of the inner diameter of the reactor. A hydrothermal reactor characterized in that a substantially complete mixing zone and a plug flow zone are formed therein.
(4) The apparatus according to (3) above, wherein a corrosion-resistant liner is provided on the inner wall of the reactor.
(5) The apparatus according to (3) or (4) above, comprising means for removing deposits from the inner wall of the reactor.
(6) The apparatus according to any one of (3) to (5) above, comprising means for cooling the reaction product in the reactor.
[0007]
In the present invention, the above-described configuration forms a substantially complete mixing zone in the reactor, and in this portion, the reactants and the oxidant are uniformly dispersed immediately after the introduction of the reactor. It is intended to form a plug flow zone underneath and react further to produce the desired hydrothermal reaction. The complete mixing zone is a zone where a completely mixed flow in which the reactants and oxidant immediately after introduction are uniformly dispersed in the zone is generated. In this way, in the complete mixing zone, the reactant and oxidant are uniformly mixed with the reactant in the zone immediately after the introduction, so that the reaction efficiency becomes high and most of the reactant (for example, 90 to 99% by weight) is absorbed. It can be decomposed in the complete mixing zone.
[0008]
The reaction product after the treatment of most of the reactants in such a substantially complete mixing region forms a plug flow region under the complete mixing region by increasing the length of the reactor. By continuing the hydrothermal reaction in the part, a reaction product obtained by decomposing the remaining reactant can be obtained.
[0009]
In the present invention, the hydrothermal reaction means that an object to be reacted is oxidized in the presence of high-temperature and high-pressure water in a supercritical or subcritical state. Here, the supercritical state is a state of 374 ° C. or higher and 22 MPa or higher. The subcritical state refers to a state of 374 ° C. or higher, 2.5 MPa or higher and lower than 22 MPa, or 374 ° C. or lower, 22 MPa or higher, or a high temperature and high pressure state close to the critical point even when 374 ° C. or lower and lower than 22 MPa.
[0010]
The to-be-reacted substance contains a substance that is a target of hydrothermal reaction such as oxidation reaction and hydrolysis reaction in a supercritical or subcritical state of water. Specific reactants include organic substances in waste liquids discharged from factories, etc., toxic substances such as PCBs, dioxins or organochlorine compounds such as trichlorethylene and environmental hormones, and water, oil, soil contaminated with them. Substances such as sludge, plastics, various inorganic substances, granular materials, their aqueous solutions or mixtures with water, human waste, sewage sludge, surplus sludge from activated sludge, and the like. Sewage sludge, human waste, surplus sludge from activated sludge, and reactants containing nitrogen such as nitrogen-containing organic substances such as amines, amino acids and proteins are suitable as objects of the present invention. This is because, in order to decompose these nitrogen-containing materials into nitrogen gas, the conventional hydrothermal reaction requires a higher reaction temperature and a longer reaction time. Such a reactant is introduced into the reactor in a state of being mixed with an oxidant, and undergoes a hydrothermal reaction. Examples of the oxidizing agent include oxygen-containing gases such as air and peroxides such as hydrogen peroxide.
[0011]
When supplying a to-be-reacted substance, a hydrothermal reaction is performed by supplying organic substances and oxides separately or mixed to the reactor. In such a hydrothermal reaction system, water is present in addition to the reactant, and if necessary, a catalyst, a neutralizing agent, etc. may be added, but these may also be mixed with the reactant or separately. The reactor can be fed.
[0012]
The reactor used in the present invention is formed of a cylindrical vessel arranged in a substantially vertical direction by a heat-resistant and pressure-resistant material so as to perform a hydrothermal reaction in a supercritical or subcritical state. When the supercritical or subcritical state is not reached due to the reaction heat, the workpiece can be preheated before being introduced into the reactor, or auxiliary fuel can be added to the workpiece. The shape of the container can be a cylinder, an elliptic cylinder, or a polygonal cylinder, and the lower end is preferably a cone. When a hydrothermal reaction is carried out in a supercritical or subcritical state using such a reactor, the organic substance to be reacted is oxidized by an oxidizing agent and finally decomposed into water and carbon dioxide, or reduced in molecular weight by hydrolysis. To do. The reaction product is cooled and decompressed, and separated into a gas component and a liquid component.
[0013]
In order to supply the reactant and the oxidizing agent to the reactor that performs the hydrothermal reaction in the supercritical or subcritical state, the reactant supply path and the oxidizing agent supply path for supplying the reactant and the oxidizing agent are respectively provided. It is provided so as to communicate with the upper part of the reactor through a high-pressure feed pump. When the reactant and the oxidant are mixed, a common supply path can be used. In order to perform the hydrothermal reaction in the reactor in a steady state, each supply pump is configured to supply the reactant and the oxidizing agent at a constant flow rate. At the bottom of the reactor, a reactant take-out path for taking out the reactant is provided in communication.
[0014]
The injection mechanism is provided so as to inject downward from the upper part of the reactor in a state where the reactant supplied from the reactant supply path and the oxidant supplied from the oxidant supply path are mixed. The injection mechanism is formed by an injection nozzle having an injection port, but there may be a plurality of injection ports. The injection port is usually installed near the center of the upper lid of the reaction vessel so that the injection flow is not directly injected onto the inner wall of the reactor, but piping is introduced from the upper side wall of the reaction vessel toward the lower side inside the vessel. The form to inject may be sufficient.
[0015]
In the above configuration, the reactor has a length that is 6 times or more, preferably 6 to 20 times, more preferably 6 to 15 times the inner diameter (the inner diameter of the region in which the hydrothermal reaction is substantially performed). Formed. In the present invention, when the reactor has a shape other than a cylinder, an equivalent diameter corresponding to the diameter of a hydraulically equivalent cylinder is used.
[0016]
The injection device has an inner diameter of 1/15 to 1/200, preferably 1/20 to 1/150, more preferably 1/30 to 1/100 of the inner diameter of the reactor (substantially in the region where the hydrothermal reaction takes place. The mixture of the reactant and the oxidizing agent is injected downward into the reactor at an injection speed of 10 m / sec or more, preferably 10 to 500 m / sec, more preferably 15 to 300 m / sec. Configured to do. When there are a plurality of injection ports, the inner diameter ratio is obtained by converting into the diameter of a circle having a total cross-sectional area.
[0017]
When a mixture of the reactant and the oxidant is injected downward from the injection mechanism into the reactor, a substantially complete mixing zone is formed in the reactor. The substantially complete mixing zone is usually formed in a region 4 to 8 times the inner diameter from the upper end of the reactor. In a substantially complete mixing region, a uniform circulating flow is produced in which the central portion of the reactor has a downward flow and the peripheral portion has an upward flow. When the mixture of the reactant and the oxidant is injected in the direction of the downward flow in the center, the injection flow is mixed with the circulation flow and circulated, and is uniformly dispersed in the circulation flow. For this reason, the mixture of the reactant and the oxidant injected into the substantially complete mixing zone is uniformly dispersed in the fluid in the complete mixing zone immediately after the injection and mixed with the reactant, thereby reducing the heat in the reactant. In response, the supercritical or subcritical state is reached immediately, and the hydrothermal reaction is carried out efficiently.
[0018]
In such a substantially complete mixing zone, most of the reactants (for example, 90 to 99% by weight) are decomposed. In order to further increase the decomposition rate, a plug flow zone is provided in the reactor under a substantially complete mixing zone. In the plug flow zone, a downward substantially parallel flow is formed by the weight of the reactant and the drawing force from the reactant take-out path, and the hydrothermal reaction proceeds and remains because it moves in a supercritical or subcritical state. The reactant is decomposed. It is believed that the plug flow zone below the substantially complete mixing zone needs to be at least twice as long as the inner diameter. Therefore, in order to have a substantially complete mixing zone and plug flow zone in one reactor, it is considered that the length is at least 6 times the inner diameter. The length / inner diameter ratio of this reactor to obtain a favorable mixing condition is supported by hydrodynamic analysis.
[0019]
If the ratio between the inner diameter of the reactor and the length of the reactor, the ratio of the inner diameter of the reactor to the inner diameter of the injection port, and the injection speed are out of the above ranges, uniform and substantially complete mixing even when backflow occurs in the reactor It is very difficult to get a range. In this case, it is very difficult to obtain uniform dispersion even when the mixed flow of the reactant and the oxidizing agent is injected into such a mixing zone. In such a mixing zone, the hydrothermal reaction cannot continue stably. Even if a hydrothermal reaction occurs, the reaction efficiency is not sufficiently high, and it is very difficult to decompose most of the reactants.
[0020]
In the present invention, the hydrothermal reaction can be efficiently performed by performing the hydrothermal reaction in the substantially complete mixing zone and the plug flow zone, and thereby the reactants can be decomposed with high efficiency by a small reactor. Can do. Reactants obtained by decomposing most of the reactants in the substantially complete mixing zone are continuously removed in the plug flow zone below the substantially complete mixing zone, and the remaining reactants are decomposed and removed at a high rate. The reaction product can be decomposed and removed at a high rate.
[0021]
The material for forming the reactor is not limited as long as it can withstand a hydrothermal reaction, but Hastelloy, Inconel, stainless steel and the like can be used.
[0022]
When the reactant includes a corrosive substance such as an acid or when the reaction generates a corrosive substance such as an acid, the reactor can be provided with a corrosion-resistant liner. The corrosion-resistant liner is not particularly limited, and the reactor inner surface is coated with a corrosion-resistant material such as titanium, platinum, iridium, zirconia, and titania, or a cover-like member made of the same material is directly applied to the reactor inner surface. Or the thing arrange | positioned at intervals is mention | raise | lifted. By providing such a liner, corrosion of the reactor is prevented and a hydrothermal reaction over a long period of time is possible.
[0023]
In the present invention, a solid such as an inorganic salt or an oxide generated by the reaction and an object to be processed moves downward in the reactor by the action of gravity and is discharged from the reactant outlet. It is preferable to prevent the sprayed fluid from directly contacting the inner wall of the reactor in order to prevent solid adhesion.
When the stickiness of the solid is remarkable, a removing means for removing the solid adhering to the inner wall of the reaction vessel can be provided. The solid removal means may be a mechanical device, and is not particularly limited, but is preferably a rotating frame type or a substantially cylindrical scraper having a notch window portion as disclosed in JP-A-11-156186. It is. By providing such solid matter removing means, the solid matter adhering to the inner surface of the reactor can be removed and the hydrothermal reaction can be continued for a long time.
[0024]
In the present invention, it is possible to provide a cooling means for cooling the reactant before discharging it from the reactant outlet. The cooling means is not particularly limited, but water can be introduced into the lower part of the reactor for cooling, and the inorganic salt can be dissolved in water to facilitate its discharge. In addition, water containing acid or alkali can be introduced into the reactor and cooled, and the alkali or acid can be neutralized. By providing such a cooling means, the inside of the reactor can be cooled to produce a liquid to dissolve soluble components, and it can be taken out in a neutral state by neutralization. They can be taken out and their discharge becomes easy.
[0025]
【Effect of the invention】
According to the present invention, since the hydrothermal reaction is performed by forming a substantially complete mixing zone in the reactor, the object to be treated and the oxidizing agent can be uniformly dispersed immediately after the introduction of the reactor. High efficiency can be achieved.
Furthermore, since the plug flow zone is provided under the substantially complete mixing zone and the hydrothermal reaction is continued, it can be decomposed with high efficiency in a small reactor. In this way, the object to be treated can be decomposed with high efficiency and a small reactor.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a vertical sectional view showing a hydrothermal reaction apparatus according to an embodiment.
[0027]
In FIG. 1, 1 is a reactor, which is composed of a cylindrical container having a conical portion 1a at the bottom made of a heat and pressure resistant material, and an injection mechanism 2 is provided at the top. The injection mechanism 2 includes a small cylindrical injection nozzle 4 having an injection port 3 at the lower end and a mixing unit 5. The injection nozzle 4 is attached from the upper part of the reactor 1 so that the injection port 3 opens downward into the reactor 1. A reactant supply path 8 and an oxidant supply path 9 are in communication with the reactant introduction section 6 and the oxidant introduction section 7 provided on the upper portion and the side wall of the mixing section 5, respectively.
[0028]
A corrosion-resistant liner 11 is formed on the inner wall of the reactor 1. A scraper 12 made of a cylinder having a conical portion 12a at a lower portion is provided inside the liner 11 of the reactor 1 so as to be rotatable, and a small diameter inserted into the small diameter portion 1b at the lower end portion of the reactor 1. It is made to rotate by the drive mechanism 13 connected to the part 12b. A cooling water channel 14 rises from below through the center of the small-diameter portion 1b of the reactor 1. A reactant outlet 15 is provided in the small diameter portion 1b at the lower end of the reactor 1, and a reactant outlet 16 communicates therewith.
[0029]
In the above configuration, the length of the reactor 1 (effective length in which the hydrothermal reaction is substantially performed in the reactor 1) H is the inner diameter of the reactor 1 (the hydrothermal reaction is substantially performed in the reactor 1). Effective diameter) 6 times or more than R. The inner diameter r of the injection port 3 of the injection nozzle 4 of the injection mechanism 2 is set to 1/15 to 1/200 of R, and the injection speed of the injection flow a injected from the injection port 3 is 10 m / sec or more. .
[0030]
In the hydrothermal reaction in the above apparatus, the reactant is supplied from the reactant supply path 8, the oxidant is supplied from the oxidant supply path 9 and mixed in the mixing unit 5 of the injection mechanism 2, and the mixture is injected into the injection nozzle. The hydrothermal reaction is carried out in a supercritical or subcritical state by injecting downward into the reactor 1 from the injection port 4. During this time, the scraper 12 is rotated by the driving device 13 to separate the solid matter adhering to the inner wall of the reactor 1, and cooling water is blown from the cooling water channel 14 into the lower part of the reactor 1 to cool and / or neutralize, The soluble component is dissolved in the liquefied liquid and allowed to flow down. The reactant is withdrawn from the reactant outlet 16 along with the fluid and solids.
[0031]
In the above hydrothermal reaction, a substantially complete mixing zone 21 is formed at the top of the reactor 1, a plug flow zone 22 is formed at the bottom thereof, and a cooling zone 23 is formed at the bottom thereof.
[0032]
In the substantially complete mixing zone 21, a uniform circulation flow composed of the downward flow b and the upward flow c is formed, and the injection flow a injected from the injection port 3 is mixed with the circulating downward flow b. The mixture of the reactant and the oxidant is uniformly dispersed in the circulation flow of the substantially complete mixing zone 21 immediately after injection. For this reason, the mixture receives a heat from the circulating flow and immediately becomes a supercritical or subcritical state, so that a hydrothermal reaction proceeds, and most of the reactant is decomposed while circulating in the substantially complete mixing zone 21. .
[0033]
Of the circulating flow in the substantially complete mixing zone 21, the amount corresponding to the jet flow a moves to the plug flow zone 22 and forms a downward flow d by gravity. The downward flow in the plug flow region 22 is a substantially parallel flow and flows down as a slow flow, while the hydrothermal reaction continues, and the remaining reactants are decomposed.
[0034]
In the cooling zone 23, the liquid component in the reaction product is liquefied by being cooled by the cooling water e blown from the cooling water channel 14 to a temperature below the supercritical temperature, solubilizing soluble components such as salts and dispersing solids. In this state, the reactant is taken out from the reactant outlet 16 together with the reactant.
[0035]
In the hydrothermal oxidation reaction, the reaction heat that is generated brings about a rise in sensible heat of the fluid. Since a substantially complete mixed state is formed, it is possible to keep the reaction vessel at a predetermined reaction temperature without external heating and realize a stable continuation of the reaction by appropriately selecting the amount of heat of the organic waste liquid. . Note that the reactant may be supplied intermittently. To achieve a high reaction rate, as in the case of complete decomposition of hazardous substances, the reactor length can be set to give the required residence time in the plug flow zone to achieve the target reaction rate. .
[0036]
The reactant to be supplied to the reactor 1 is normally held in a storage tank, pressurized by a high pressure pump, and supplied from the reactant supply path 8. When the object to be treated does not contain water, it can be mixed with water in advance and supplied as an aqueous solution or water slurry. Moreover, you may mix with water in the piping of the to-be-reacted material supply path 8. FIG. In the case of the hydrothermal oxidation reaction, the oxidant is similarly pressurized and supplied by a high-pressure pump or a compressor. As the oxidizing agent, air, oxygen, liquid oxygen, hydrogen peroxide solution, nitric acid, nitrous acid, nitrate, or nitrite can be used. The oxidizing agent may be supplied after being mixed with the reactant or water containing the reactant, or may be supplied as a multilayer flow with the injection nozzle 4 as a double tube nozzle.
[0037]
In particular, in the case of a hydrothermal oxidation reaction, it is preferable that the reactor 1 is kept in an adiabatic state as much as possible, and the amount of heat of the reactant is adjusted so as to reach a predetermined reaction temperature with the amount of heat generated by the reaction. However, for the reactant with a relatively low calorific value, preheat the reactant and the fluid containing the reactant and supply it, and add kerosene, alcohol, waste organic solvent, etc. to adjust the calorie Alternatively, the reaction temperature may be adjusted with an external heat source.
[0038]
The procedure for starting the reaction is not particularly limited. For example, the pressurized reactant and oxidant are preheated and introduced into the reactor 1 through the mixing section 5 of the injection mechanism 2. Preheating is accomplished with an electric heater, a heating means with combustion, or a combination thereof. Since the reaction mixture is well mixed, a hydrothermal reaction occurs, generating reaction heat, and the temperature of the fluid rises. Once a steady state is obtained in the reactor 1, preheating may be stopped if the reaction object has a sufficient amount of heat.
[0039]
The reactant taken out from the reactant outlet 16 is usually cooled and decompressed. Solid separation and gas-liquid separation processes can be performed in the course of cooling and decompression. The finally generated water, gas, and solid are recovered as they are, recovered as energy, reused as substances, or discarded as they are or after additional processing.
[0040]
【Example】
Examples of the present invention will be described below. In each example,% is% by weight.
[0041]
Example 1
From an injection nozzle 4 having an injection port 3 having an inner diameter of 1.4 mm in the center of the upper lid of the vertical cylindrical reactor 1 having a length of 1640 mm and an inner diameter of 108 mm, water, Injected with air, a hydrothermal oxidation reaction was performed in a supercritical state, the reactant was taken out from the reactant outlet 16 at the lower end, gas-liquid separated, and the water quality and decomposition rate of the separated liquid were measured. Table 2 shows the operating conditions and results. In the operation, the reactor 1 was preheated to the reaction temperature with an external heat source in advance.
As shown in Table 2, the hydrothermal oxidation reaction was possible at 640 ° C., 22.5 MPa, and a residence time of 22 seconds, and the organic matter was completely decomposed. The stable reaction continued for about 3 hours. Although observed after the reaction, no scale formation or clogging was observed due to the generated inorganic substance.
[0042]
Example 2
Using the same reactor and organic waste as in Example 1, a hydrothermal oxidation reaction was performed in a subcritical state together with water and air. Table 2 shows the operating conditions and results.
As shown in Table 2, the hydrothermal oxidation reaction was possible at 650 ° C., 14.8 MPa, residence time 19 seconds, and the organic matter was completely decomposed. The stable reaction continued for about 3 hours. In addition, although observed after the reaction, scale generation or clogging due to the generated inorganic substance was not observed.
[0043]
Example 3
The sewage sludge having the composition shown in Table 3 was subjected to a hydrothermal reaction in a supercritical state using the reactor used in Example 1. Sewage sludge was injected with air and water after preheating. The injection nozzle adjusted the diameter of the opening to 3.0 mm.
As shown in Table 4, a hydrothermal reaction was performed at 615 ° C., 22.3 MPa, and a residence time of 19 seconds, and organic carbon (TOC) and nitrogen (TN) were completely decomposed. The reaction continued stably for 3 hours. In the observation after the reaction, scale generation or clogging due to the generated inorganic substance was not observed.
[0044]
[Table 1]

[0045]
[Table 2]

[0046]
[Table 3]

[0047]
[Table 4]

[0048]
Comparative Example 1
The injection nozzle of the injection mechanism of the reactor of Example 1 was changed to a nozzle having an injection port diameter of 9 mm. Using the same organic waste drug as in Example 1, a hydrothermal oxidation reaction was performed in a supercritical state with water and air.
The hydrothermal reaction was started under the same conditions as in Example 1 with the reactant supply rate of 0.12 kg / min, water supply rate of 1.00 kg / min, and air supply rate of 2.22 kg / min, but the reaction continued Without this, a fluid containing black material that seems to be char generated by incomplete combustion was discharged.
In this comparative example, the inner diameter of the injection port is 1/12 of the inner diameter of the reactor, the injection speed is 1.7 m / sec, and the reaction fluid containing the reactant and the oxidizing agent is not sufficiently mixed. It is determined that the temperature rise due to the reaction, the progress of the reaction, and the start of the reaction of the supplied workpiece were not realized satisfactorily.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a hydrothermal reactor according to an embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Reactor 2 Injection mechanism 3 Injection port 4 Injection nozzle 5 Mixing part 6 Reactant introduction part 7 Oxidant introduction part 8 Reactant supply path 9 Oxidant supply path 11 Liner 12 Scraper 13 Drive mechanism 14 Cooling water path 15 Reactant Extraction section 16 Reactant extraction path 21 Complete mixing zone 22 Plug flow zone 23 Cooling zone

Claims (6)

To a cylindrical reactor which is arranged in a substantially vertical direction and has a length of more than 6 times the inner diameter,
The mixture of the reactant and the oxidant is injected from the upper part of the reactor by an injection mechanism at an injection speed of 10 m / sec or more through an injection port having an inner diameter of 1/15 to 1/200 of the inner diameter of the reactor,
A hydrothermal reaction method characterized in that a substantially complete mixing zone and a plug flow zone are formed in the reactor thereby to perform a hydrothermal reaction in a supercritical or subcritical state of water. 2. The method according to claim 1, wherein the reactant is a nitrogen-containing substance. A cylindrical reactor arranged in a substantially vertical direction to perform a hydrothermal reaction in a supercritical or subcritical state of water;
A reactant supply path for supplying the reactant to the upper part of the reactor;
An oxidant supply path for supplying an oxidant to the top of the reactor;
An injection mechanism for injecting the reactant supplied from the reactant supply path and the oxidant supplied from the oxidant supply path from the upper part of the reactor in a mixed state;
A reactant take-out path for taking out the reactant from the lower part of the reactor,
The reactor has a length of at least six times the inner diameter;
The injection mechanism is configured to inject a mixture of a reactant and an oxidant into the reactor at an injection speed of 10 m / sec or more from an injection port having an inner diameter of 1/15 to 1/200 of the inner diameter of the reactor. A hydrothermal reactor characterized in that a substantially complete mixing zone and a plug flow zone are formed therein. The apparatus of claim 3 having a corrosion resistant liner on the inner wall of the reactor. The apparatus according to claim 3 or 4, further comprising means for removing deposits from the inner wall of the reactor. The apparatus according to any one of claims 3 to 5, further comprising means for cooling the reaction product in the reactor.

Images