A corrosion-resistant process and system for supercritical hydrothermal oxidation graded treatment of organic waste

Abstract

The present invention relates to the technical field of supercritical water oxidation treatment of organic hazardous waste, and specifically discloses a corrosion-resistant process and system for supercritical water thermal oxidation graded treatment of organic waste. The corrosion-resistant system for supercritical water thermal oxidation graded treatment of organic waste comprises a supercritical water oxidation unit, an oxygen supply unit and a waste heat utilization unit. Supercritical water thermal treatment of organic waste is carried out in the supercritical water oxidation unit, the oxygen supply unit provides oxygen to the supercritical water oxidation unit, and the waste heat utilization unit recovers waste heat. The present invention also designs a reactor structure to reduce the corrosion problem of the reactor under supercritical water thermal treatment conditions, obtains hydrogen-rich gas in the supercritical water oxidation unit, improves the corrosion resistance of the supercritical water thermal oxidation graded treatment system for organic waste, realizes deep degradation of ammonia nitrogen in the organic waste, and improves the efficiency and environmental friendliness of the entire system.

Description

Technical Field

[0001] The invention relates to the field of supercritical water oxidation treatment of organic hazardous waste, and specifically discloses a corrosion-resistant process and system for supercritical water thermal oxidation graded treatment of organic waste. Background Art

[0002] The critical temperature of water is 374.3°C, and the critical pressure is 22.1 MPa. Water with a temperature and pressure exceeding the critical point is called supercritical water (SCW). SCW is a good reaction medium due to its high heat transfer and minimal diffusion restrictions. Supercritical water oxidation (SCWO) is a method that uses the characteristics of supercritical water to achieve deep treatment of organic pollutants. SCWO reacts quickly, usually within a few seconds to a few minutes, it can degrade more than 99% of organic matter into benign compounds and small molecular compounds, such as CO2, N2, H2O, which are environmentally friendly substances. Various heteroatoms are also oxidized into corresponding acids or precipitated in the form of salts. Supercritical water oxidation technology for treating waste has the characteristics of high removal efficiency, short residence time, and no pollutants and by-products.

[0003] Despite its high efficiency and thoroughness in waste treatment, supercritical water oxidation technology still faces numerous challenges due to its demanding reaction conditions, including equipment corrosion, catalyst selection, lack of data, inorganic salt deposition, process exotherm, and the fact that thermodynamic research has yet to begin. The most immediate and significant issue is equipment corrosion. Supercritical water oxidation occurs under high temperature and pressure, causing severe corrosion to equipment such as reaction vessels. This is particularly true when halogen elements such as Cl, Br, and F, as well as S and P, are present in the reactant stream. Therefore, the equipment corrosion problem caused by these harsh reaction conditions urgently needs to be addressed. Currently, reactors are primarily manufactured using alloy materials such as nickel-based alloys, titanium alloys, and stainless steel. However, both generalized and localized corrosion can still occur, and in severe cases, this can cause reactor leakage or even explosion.

[0004] Furthermore, because the temperature and pressure of supercritical water treatment reactions are both higher than the critical point of water, both the preheating and cooling stages of liquid or slurry materials in supercritical water treatment systems must pass through the transcritical water system. However, the actual operation of supercritical water treatment demonstration and industrial plants has shown that the risk of corrosion failure of equipment in service in transcritical water systems is the highest, and this is a common bottleneck that restricts the industrialization of many supercritical water treatment technologies. Summary of the Invention

[0005] In response to the above-mentioned deficiencies in the prior art, the present invention provides a corrosion-resistant process and system for the graded treatment of organic waste by supercritical hydrothermal oxidation. The present invention designs the structure of the reactor to overcome the problem of reactor corrosion under supercritical hydrothermal treatment conditions, and sets up a supercritical water oxidation unit to obtain hydrogen-rich gas, thereby improving the corrosion resistance of the equipment. It also achieves deep degradation of ammonia nitrogen in organic waste, thereby improving the efficiency of the entire corrosion-resistant system for the graded treatment of organic waste by supercritical hydrothermal oxidation, ensuring the complete conversion of organic waste, and reducing the pollution of untreated organic matter to the environment.

[0006] To achieve the above object, the present invention is implemented through the following technical solutions:

[0007] A corrosion-resistant system for treating organic waste by supercritical water thermal oxidation graded treatment comprises a supercritical water oxidation unit in which supercritical water thermal treatment of the organic waste is carried out.

[0008] The supercritical water oxidation unit includes a material buffer tank, a product separator, a first heat exchanger, a second heat exchanger, a reactor, a third heat exchanger, a product collector and a secondary reactor; the organic waste is stored in the material buffer tank; the product separator is used to separate the organic waste and obtain hydrogen-rich gas and hot fluid; the first heat exchanger and the second heat exchanger are used to heat the hot fluid and exchange heat with the mixed fluid; the supercritical water heat treatment of the organic waste is carried out in the reactor, that is, the organic waste is oxidized; the hydrogen-rich gas is exchanged with the impurities discharged from the bottom outlet of the reactor in the third heat exchanger; the product collector is used to collect the heat exchanged The impurities are cooled, and the secondary reactor is used for deep degradation reaction of ammonia nitrogen. The material buffer tank, the first heat exchanger and the product separator are connected through a first pipeline; the top outlet of the product separator is connected to the third heat exchanger through a second pipeline, the bottom outlet of the product separator is connected to the reactor through a third pipeline, and the product collector is connected to the third heat exchanger; the second heat exchanger is installed on the third pipeline; the third heat exchanger, the second heat exchanger and the third heat exchanger are connected through a fourth pipeline; the secondary reactor is installed between the fourth pipeline and the top outlet of the reactor through a fifth pipeline, and the connection between the fifth pipeline and the fourth pipeline is located between the second heat exchanger and the third heat exchanger.

[0009] The reactor includes an outer shell and a reaction unit. The reaction unit is arranged in the outer shell. The reaction unit includes a low-alloy rod and two ceramic separators. The low-alloy rod is installed in the reactor through a corrosion-resistant plug-in, and the two ceramic separators are arranged on both sides of the low-alloy rod. The low-alloy rod has good heat storage capacity, which is conducive to promoting the oxidation of organic waste. In addition, the low-alloy rod decomposes during the oxidation reaction and self-generates a catalyst, further realizing the degradation of ammonia nitrogen.

[0010] Multiple electrode nodes are provided on the corrosion-resistant plug-in and the shell of the reactor. The low-alloy rod is electrically connected to the electrode nodes on the reactor shell through the electrode nodes on the corrosion-resistant plug-in as needed. The low-alloy rod is easily corroded. The low-alloy rod is used as the anode and the reactor shell is used as the cathode. The shell of the reactor is protected by galvanic corrosion in the form of a sacrificial anode.

[0011] Preferably, the ceramic separator is selected from an alumina-stabilized zirconia separator or a ceria-stabilized zirconia separator. The ceramic separator allows the dilute fluid after the reaction to leave from the top outlet of the reactor, enter the secondary reactor through the fifth pipe, and perform deep degradation of ammonia nitrogen.

[0012] Preferably, the low alloy rod is selected from magnesium alloy rod, zinc alloy rod, aluminum alloy rod or carbon steel rod.

[0013] Preferably, a check valve is provided on the fifth pipeline between the secondary reactor and the fourth pipeline to prevent backflow of the dilute fluid.

[0014] Preferably, the corrosion-resistant system for supercritical water thermal oxidation graded treatment of organic waste also includes an oxygen supply unit and a waste heat utilization unit, which are jointly connected to the supercritical water oxidation unit. The oxygen supply unit provides oxygen to the supercritical water oxidation unit, and the waste heat utilization unit recovers waste heat.

[0015] Preferably, the waste heat utilization unit includes a first heat exchanger, a fourth heat exchanger and a solid-liquid separator. The first heat exchanger is installed on the first pipeline. A material pump is also provided on the first pipeline between the material buffer tank and the first heat exchanger to facilitate the discharge of material in the material buffer tank. The second heat exchanger, the first heat exchanger, the fourth heat exchanger and the solid-liquid separator are connected in sequence through the seventh pipeline. The fourth heat exchanger can effectively recover the heat of the mixed fluid coming out of the first heat exchanger and use it to heat the external water. The mixed fluid is separated into products through the solid-liquid separator.

[0016] Preferably, a thermometer is provided on the first pipe between the first heat exchanger and the product separator, and a switch valve is provided on the fourth pipe bypass between the second heat exchanger and the first heat exchanger. The thermometer is interlocked with the switch valve, and the opening and closing of the switch valve is regulated by the temperature monitored by the thermometer.

[0017] Preferably, a COD meter is provided at the outlet end of the fourth heat exchanger, and a first control valve is provided on the second pipeline. The COD meter is interlocked with the first control valve. The purpose of measuring COD here is to better reduce the dissolved oxygen in the fluid after the reaction, thereby reducing the degree of corrosion of the fluid equipment.

[0018] Preferably, the oxygen supply unit includes a liquid oxygen storage tank, a liquid oxygen pump and a liquid oxygen vaporizer, the sixth pipeline is connected between the oxygen storage tank and the reactor, the liquid oxygen pump and the liquid oxygen vaporizer are installed together on the sixth pipeline, and the liquid oxygen pump is located between the liquid oxygen storage tank and the liquid oxygen vaporizer.

[0019] The present invention also provides a process for a corrosion-resistant system for treating organic wastes by supercritical water thermal oxidation, comprising the following steps:

[0020] The liquid oxygen in the liquid oxygen storage tank is transported to the liquid oxygen vaporizer by the liquid oxygen pump and vaporized, and then transported to the reactor.

[0021] The organic waste in the material buffer tank is first preheated by the first heat exchanger, and then enters the product separator for separation to obtain hydrogen-rich gas and hot fluid; the hot fluid enters the second heat exchanger through the bottom outlet of the product separator and is heated again, then enters the reactor, where it is mixed with oxygen and subjected to supercritical hydrothermal treatment of the organic waste to obtain impurities and dilute fluid.

[0022] The hydrogen-rich gas is discharged through the top outlet of the product separator and exchanges heat with the impurities discharged from the bottom outlet of the reactor in the third heat exchanger. The impurities that have been cooled after the exchange are discharged into the product collector. The impurities have a high solid content. Under the action of centrifugal force, they flow through the bottom of the reactor into the third heat exchanger to exchange heat with the hydrogen-rich gas, thereby achieving the purpose of increasing the heat and pressure of the hydrogen-rich gas and recovering the heat of the solid impurities. The impurities that have been cooled after the exchange are discharged into the product collector. The impurities discharged from the bottom of the reactor have a high solid content. The centrifugal force generated by the rotation or rapid change of direction of the fluid during the flow process causes the solid particles to move to the bottom due to their heavier mass, thereby achieving solid-liquid separation.

[0023] The dilute fluid flows out through the top outlet of the reactor and undergoes a deep degradation reaction of ammonia nitrogen in the secondary reactor to obtain a degraded fluid. The degraded fluid is mixed with the hydrogen-rich gas after heat exchange to obtain a mixed fluid. After the mixed fluid exchanges heat with the second heat exchanger, the first heat exchanger and the fourth heat exchanger in sequence, it enters the solid-liquid separator for solid-liquid separation.

[0024] While supercritical hydrothermal treatment of organic waste is being carried out in the reactor, ammonia nitrogen degradation reaction is also carried out under the catalytic action of low-alloy rods. The dilute fluid obtained by the reaction enters the secondary reactor through the top outlet of the reactor under the action of the ceramic separator, and undergoes deep degradation of ammonia nitrogen.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention solves the problem of equipment corrosion during the supercritical water treatment reaction from two perspectives. First, the present invention heats organic waste in a gas collector and separator to obtain hydrogen-rich gas, which is mixed with a degradation fluid. The hydrogen-rich gas is used to consume the dissolved oxygen in the degradation fluid, thereby reducing the degree of corrosion of the fluid on the equipment. Secondly, the reactor of the present invention uses a corrosive low-alloy rod as an anode and a reactor shell as a cathode. The shell of the reactor is provided with multiple electrode nodes. The low-alloy rod is electrically connected to the electrode node on the corrosion-resistant plug-in and the electrode node on the reactor shell. The shell of the reactor is protected by a sacrificial anode through galvanic corrosion, thereby reducing the degree of corrosion of the reactor.

[0027] 2. The present invention provides a reactor, which is equipped with corroded low-alloy rods, which react during the corrosion process and produce a catalyst for degrading ammonia nitrogen. The present invention also provides a secondary reactor, which deeply degrades the ammonia nitrogen in the dilute fluid. The reduction in ammonia nitrogen content can improve the efficiency of the entire corrosion-resistant system for supercritical hydrothermal oxidation graded treatment of organic waste, promote the further transformation of organic waste, and reduce the pollution of untreated organic matter to the environment.

[0028] 3. While realizing the supercritical water thermal treatment of organic waste, the present invention reduces the degree of fluid corrosion on equipment during the supercritical water treatment reaction, realizes the deep degradation of ammonia nitrogen in organic waste, realizes the recovery and utilization of waste heat, and has economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is an overall flow chart of the corrosion-resistant system for the supercritical water thermal oxidation graded treatment of organic wastes of the present invention.

[0030] Description of reference numerals:

[0031] 1-Liquid oxygen storage tank, 2-Liquid oxygen pump, 3-Liquid oxygen vaporizer, 4-Sixth pipeline, 5-Second pipeline, 6-First control valve, 7-Material buffer tank, 8-Material pump, 9-First heat exchanger, 10-First pipeline, 11-Thermometer, 12-Product separator, 13-Third pipeline, 14-Secondary reactor, 15-Check valve, 16-Fifth pipeline, 17-Electrode node, 18-Corrosion-resistant plug-in, 19-Ceramic separator, 20-Low alloy rod, 21-Reactor, 22-Third heat exchanger, 23-Fourth pipeline, 24-Second heat exchanger, 25-Switch valve, 26-Fourth heat exchanger, 27-COD meter, 28-Seventh pipeline, 29-Solid-liquid separator, 30-Second control valve, 31-Product collector. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "one side", "one end", "one side" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0034] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0035] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0036] It should also be understood that the terms used in the present specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0037] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0038] The accompanying drawings illustrate various schematic diagrams of structures according to embodiments disclosed herein. These figures are not drawn to scale; for clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0039] Hereinafter, the corrosion-resistant process and system for treating organic waste by supercritical hydrothermal oxidation classification according to the present invention will be described in detail with reference to the accompanying drawings and embodiments.

[0040] A corrosion-resistant system for supercritical hydrothermal oxidation graded treatment of organic waste, such as Figure 1 As shown, it includes a supercritical water oxidation unit, which includes a material buffer tank 7, a first heat exchanger 9, a product separator 12, a second heat exchanger 24, a reactor 21, a third heat exchanger 22, a product collector 31 and a secondary reactor 14; the material buffer tank 7 is connected to the product separator 12 through a first pipe 10; the top outlet of the product separator 12 is connected to the third heat exchanger 22 through a second pipe 5, and the product collector 31 is also connected to the third heat exchanger 22; the bottom outlet of the product separator 12 is connected to the reactor 21 through a third pipe 13, and the second heat exchanger 24 is installed on the third pipe 13; the third heat exchanger 22 and the second heat exchanger 24 are connected through a fourth pipe 23; the secondary reactor 14 is installed between the fourth pipe 23 and the top outlet of the reactor 21 through a fifth pipe 16, and the connection between the fifth pipe 16 and the fourth pipe 23 is located between the second heat exchanger 24 and the third heat exchanger 22.

[0041] The reactor 21 includes an outer shell and a reaction unit. The reaction unit is arranged in the outer shell. The reaction unit includes a low-alloy rod 20 and two ceramic separators 19. The low-alloy rod 20 is installed in the reactor 21 through a corrosion-resistant plug-in 18. The two ceramic separators 19 are arranged on both sides of the low-alloy rod 20.

[0042] A plurality of electrode nodes 17 are provided on both the corrosion-resistant insert 18 and the shell of the reactor 21 , and the low-alloy rod 20 is electrically connected to the electrode nodes on the shell of the reactor 21 via the electrode nodes on the corrosion-resistant insert 18 .

[0043] Furthermore, a check valve 15 is provided on the fifth pipeline 16 between the secondary reactor 14 and the fourth pipeline 23 .

[0044] Furthermore, the corrosion-resistant system for supercritical water thermal oxidation graded treatment of organic waste also includes an oxygen supply unit and a waste heat utilization unit, and the oxygen supply unit and the waste heat utilization unit are jointly connected to the supercritical water oxidation unit.

[0045] Furthermore, the waste heat utilization unit includes a first heat exchanger 9, a fourth heat exchanger 26 and a solid-liquid separator 29. The first heat exchanger 9 is installed on the first pipeline 10. A material pump 8 is also provided on the first pipeline 10 between the material buffer tank 7 and the first heat exchanger 9. The second heat exchanger 24, the first heat exchanger 9, the fourth heat exchanger 26 and the solid-liquid separator 29 are connected in sequence through the seventh pipeline 28.

[0046] Furthermore, a thermometer 11 is provided on the first pipe 10 between the first heat exchanger 9 and the product separator 12 , and a switch valve 25 is provided on the bypass of the fourth pipe 23 between the second heat exchanger 24 and the first heat exchanger 9 , and the thermometer 11 is interlocked with the switch valve 25 .

[0047] Furthermore, a COD meter 27 is provided at the outlet end of the fourth heat exchanger 26 , and a first control valve 6 is provided on the second pipeline 5 . The COD meter 27 is interlocked with the first control valve 6 .

[0048] Furthermore, the oxygen supply unit includes a liquid oxygen storage tank 1, a liquid oxygen pump 2 and a liquid oxygen vaporizer 3. The sixth pipeline 4 is connected between the oxygen storage tank 1 and the reactor 21. The liquid oxygen pump 2 and the liquid oxygen vaporizer 3 are installed together on the sixth pipeline 4, and the liquid oxygen pump 2 is located between the liquid oxygen storage tank 1 and the liquid oxygen vaporizer 3.

[0049] Example 1

[0050] A process for a corrosion-resistant system for treating organic waste by supercritical hydrothermal oxidation graded treatment comprises the following steps:

[0051] In the sixth pipeline 4 , liquid oxygen is transported from the liquid oxygen storage tank 1 to the liquid oxygen vaporizer 3 via the liquid oxygen pump 2 . After the liquid oxygen is vaporized in the liquid oxygen vaporizer 3 , it is transported to the reactor 21 .

[0052] In the first pipeline 10, the organic waste is first preheated by the first heat exchanger 9, and then enters the product separator 12 for separation to obtain hot fluid and hydrogen-rich gas.

[0053] In the third pipe 13, part of the hot fluid leaves the bottom outlet of the product separator 12 and enters the second heat exchanger 24. After being heated again, it enters the reactor 21, mixes with oxygen and performs supercritical hydrothermal treatment on the organic waste.

[0054] In the second pipeline 5 , the hydrogen-rich gas passes through the first control valve 6 from the top outlet of the product separator 12 and then exchanges heat with the impurities discharged from the bottom outlet of the reactor 21 in the third heat exchanger 22 .

[0055] In the fifth pipe 16 , the dilute fluid flows out through the top outlet of the reactor 21 and undergoes a deep degradation reaction of ammonia nitrogen in the secondary reactor 14 to obtain a degraded fluid.

[0056] In the fourth pipeline 23, the degradation fluid is mixed with the hydrogen-rich gas after heat exchange to obtain a mixed fluid. The hydrogen-rich gas consumes the residual dissolved oxygen in the degradation fluid. The mixed fluid then returns to the first heat exchanger 9 through the second heat exchanger 24 and transfers heat to the organic waste. After leaving the first heat exchanger 9, the mixed fluid enters the fourth heat exchanger 26 to exchange heat with the feed water outside the system to achieve the purpose of cooling and reducing pressure. Then, it enters the solid-liquid separator 29 for solid-liquid separation to obtain a recovered product.

[0057] The solid-liquid separator 29 is provided with a solid outlet and a liquid outlet. A second control valve 30 is provided at the solid outlet to control the discharge of the material.

[0058] A COD meter 27 is provided at the outlet end of the fourth heat exchanger 26, and a first control valve 6 is provided on the second pipeline 5. The COD meter 27 is interlocked with the first control valve 6. The COD meter 27 is used to measure the organic pollutants in the mixed fluid. When the COD is too high, the first control valve 6 is opened wide to allow more hydrogen-rich gas to mix with the degradation fluid to reduce the COD; a thermometer 11 is provided on the first pipeline 10 between the first heat exchanger 9 and the product separator 12, and a switch valve 25 is provided on the bypass of the fourth pipeline 23 between the second heat exchanger 24 and the first heat exchanger 9. The thermometer 11 is interlocked with the switch valve 25. When the temperature measured by the thermometer 11 is higher than 350°C, the switch valve 25 is adjusted wide to discharge part of the mixed fluid to control the temperature of the organic waste in the first heat exchanger 9 below 350°C.

[0059] The hot fluid enters the reactor 21 for supercritical hydrothermal treatment, and ammonia nitrogen is degraded simultaneously under the catalytic action of the low-alloy rod 20. The low-alloy rod 20 is electrically connected to the electrode node of the outer shell of the reactor 21 through the electrode node on the corrosion-resistant plug 18 to protect the outer shell of the reactor 21 and reduce the corrosion of the outer shell of the reactor 21; the ceramic separator 19 allows the dilute fluid after supercritical hydrothermal treatment to be discharged from the top opening of the reactor 21, and enters the secondary reactor 14 through the fifth pipe 16 for deep degradation of ammonia nitrogen to obtain a degraded fluid, and then the degraded fluid leaves the secondary reactor 14 and merges with the hydrogen-rich gas coming out of the bottom outlet of the third heat exchanger 22 through the check valve 15.

[0060] Under the action of centrifugal force, the impurities after the reaction containing more solids are discharged through the bottom outlet of the reactor 21 and enter the third heat exchanger 22, and exchange heat with the hydrogen-rich gas. After leaving the third heat exchanger 22, the impurities after the reaction containing more solids enter the product collector 31 for collection.

[0061] Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims and their equivalents, such modifications and variations are intended to be included.

Claims

1. A corrosion-resistant system for treating organic waste by supercritical hydrothermal oxidation, characterized in that: The invention comprises a supercritical water oxidation unit, wherein the supercritical water oxidation unit comprises a material buffer tank (7), a product separator (12), a first heat exchanger (9), a second heat exchanger (24), a reactor (21), a third heat exchanger (22), a product collector (31) and a secondary reactor (14); the material buffer tank (7) is connected to the product separator (12) through a first pipe (10); the top outlet of the product separator (12) is connected to the third heat exchanger (22) through a second pipe (5); the bottom outlet of the product separator (12) is connected to the reactor (21) through a third pipe (1 3) connected, the product collector (31) is also connected to the third heat exchanger (22); the second heat exchanger (24) is installed on the third pipe (13); the third heat exchanger (22), the second heat exchanger (24) and the first heat exchanger (9) are connected through a fourth pipe (23); the secondary reactor (14) is installed between the fourth pipe (23) and the top outlet of the reactor (21) through a fifth pipe (16), and the connection point between the fifth pipe (16) and the fourth pipe (23) is located between the second heat exchanger (24) and the third heat exchanger (22); The reactor (21) comprises a shell and a reaction unit, wherein the reaction unit is arranged in the shell, and the reaction unit comprises a low alloy rod (20) and two ceramic separators (19), wherein the low alloy rod (20) is installed in the reactor (21) through a corrosion-resistant plug (18), and the two ceramic separators (19) are arranged on both sides of the low alloy rod (20); A plurality of electrode nodes (17) are provided on both the corrosion-resistant plug-in (18) and the shell of the reactor (21), and the low-alloy rod (20) is electrically connected to the electrode nodes on the shell of the reactor (21) through the electrode nodes (17) on the corrosion-resistant plug-in (18).

2. The corrosion-resistant system for treating organic waste by supercritical water thermal oxidation classification according to claim 1 is characterized in that: The material of the ceramic separator (19) is selected from alumina-stabilized zirconia or ceria-stabilized zirconia.

3. The corrosion-resistant system for treating organic waste by supercritical water thermal oxidation classification according to claim 2 is characterized in that: The low alloy rod (20) is selected from a magnesium alloy rod, a zinc alloy rod, an aluminum alloy rod or a carbon steel rod.

4. The corrosion-resistant system for treating organic waste by supercritical water thermal oxidation classification according to claim 3 is characterized in that: A check valve (15) is provided on the fifth pipeline (16) between the secondary reactor (14) and the fourth pipeline (23).

5. The corrosion-resistant system for treating organic waste by supercritical water thermal oxidation classification according to claim 4 is characterized in that: The corrosion-resistant system for supercritical water thermal oxidation graded treatment of organic waste also includes an oxygen supply unit and a waste heat utilization unit, and the oxygen supply unit and the waste heat utilization unit are jointly connected to the supercritical water oxidation unit.

6. The corrosion-resistant system for treating organic waste by supercritical water thermal oxidation classification according to claim 5, characterized in that: The waste heat utilization unit comprises the first heat exchanger (9), a fourth heat exchanger (26) and a solid-liquid separator (29); the first heat exchanger (9) is installed on the first pipe (10); a material pump (8) is further provided on the first pipe (10) between the material buffer tank (7) and the first heat exchanger (9); the second heat exchanger (24), the first heat exchanger (9), the fourth heat exchanger (26) and the solid-liquid separator (29) are connected in sequence through a seventh pipe (28).

7. The corrosion-resistant system for treating organic waste by supercritical water thermal oxidation classification according to claim 6, characterized in that: A thermometer (11) is provided on the first pipe (10) between the first heat exchanger (9) and the product separator (12), and a switch valve (25) is provided on the bypass of the fourth pipe (23) between the second heat exchanger (24) and the first heat exchanger (9), and the thermometer (11) is interlocked with the switch valve (25).

8. The corrosion-resistant system for treating organic waste by supercritical water thermal oxidation classification according to claim 7, characterized in that: A COD meter (27) is provided at the outlet end of the fourth heat exchanger (26), a first control valve (6) is provided on the second pipeline (5), and the COD meter (27) is interlocked with the first control valve (6).

9. The corrosion-resistant system for treating organic waste by supercritical water thermal oxidation classification according to claim 8, characterized in that: The oxygen supply unit comprises a liquid oxygen storage tank (1), a liquid oxygen pump (2) and a liquid oxygen vaporizer (3); a sixth pipeline (4) is connected between the oxygen storage tank (1) and the reactor (21); the liquid oxygen pump (2) and the liquid oxygen vaporizer (3) are installed together on the sixth pipeline (4); and the liquid oxygen pump (2) is located between the liquid oxygen storage tank (1) and the liquid oxygen vaporizer (3).

10. A process for the corrosion-resistant system for treating organic waste by supercritical hydrothermal oxidation classification according to claim 9, characterized in that: The steps include: The liquid oxygen in the liquid oxygen storage tank (1) is transported to the liquid oxygen vaporizer (3) by the liquid oxygen pump (2) and is vaporized, and then transported to the reactor (21); The organic waste in the material buffer tank (7) is first preheated by the first heat exchanger (9), and then enters the product separator (12) for separation to obtain hydrogen-rich gas and hot fluid; the hot fluid enters the second heat exchanger (24) through the bottom outlet of the product separator (12) and is heated again, and then enters the reactor (21), where it is mixed with oxygen and subjected to supercritical hydrothermal treatment of the organic waste to obtain impurities and dilute fluid; The hydrogen-rich gas is discharged through the top outlet of the product separator (12) and undergoes heat exchange with the impurities discharged from the bottom outlet of the reactor (21) in the third heat exchanger (22). The impurities cooled after the heat exchange are discharged into the product collector (31); The dilute fluid flows out through the top outlet of the reactor (21) and undergoes a deep degradation reaction of ammonia nitrogen in the secondary reactor (14) to obtain a degraded fluid, and the degraded fluid is mixed with the hydrogen-rich gas after heat exchange to obtain a mixed fluid. The mixed fluid sequentially exchanges heat with the second heat exchanger (24), the first heat exchanger (9) and the fourth heat exchanger (26), and then enters the solid-liquid separator (29) for solid-liquid separation; While the supercritical hydrothermal treatment of organic waste is being carried out in the reactor (21), ammonia nitrogen degradation reaction is also carried out under the catalytic action of the low alloy rod (20). The dilute fluid obtained by the reaction enters the secondary reactor (14) through the top outlet of the reactor (21) under the action of the ceramic separator (19) and undergoes deep degradation of ammonia nitrogen.

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