Chemical wastewater treatment system based on catalytic wet oxidation reaction

Abstract

The utility model discloses a chemical wastewater treatment system based on catalytic wet oxidation reaction, and relates to the technical field of wastewater treatment. The chemical wastewater treatment system comprises a pretreatment unit, a heat exchanger, a hydrodynamic cavitation device, a catalytic wet oxidation reactor, a gas-liquid separator, a micro-nano bubble generator and a cyclone generator, at least two stages of catalyst bed layers are arranged in the catalytic wet oxidation reactor, the porosity is gradually reduced from top to bottom, and the catalyst activity is gradually increased. In order to solve the problems of low oxidation efficiency, incomplete pollutant removal and the like in the traditional chemical wastewater wet oxidation treatment technology, the in-situ coupling design of hydrodynamic cavitation, micro-nano bubbles and catalytic wet oxidation is matched with a gradient catalyst bed layer and a system energy recovery structure, so that the treatment efficiency of the chemical wastewater is greatly improved. And high-efficiency treatment of the high-concentration refractory chemical wastewater is realized.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology, specifically to a chemical wastewater treatment system based on catalytic wet oxidation reaction. Background Technology

[0002] As a core pillar industry of the national economy, the chemical industry generates large amounts of high-concentration organic wastewater during its production processes. This wastewater is extremely complex, containing not only benzene compounds, heterocyclic compounds, and halogenated hydrocarbons—all recalcitrant organic pollutants—but also high concentrations of COD (chemical oxygen demand) and ammonia nitrogen. Its biodegradability (B / C ratio) is generally below 0.2, classifying it as typical industrial recalcitrant wastewater. Direct discharge would cause irreversible damage to aquatic ecosystems. Traditional biological treatment processes are inefficient due to their inability to withstand the toxicity of the wastewater and their difficulty in degrading large organic molecules, making it difficult to meet discharge standards. Therefore, highly efficient pretreatment technologies are urgently needed to reduce the toxicity, improve standards, and enhance the biodegradability of the wastewater.

[0003] Wet oxidation technology, as a highly efficient advanced oxidation technology, can utilize oxygen to oxidize and decompose organic matter in wastewater into inorganic products such as CO2 and H2O under high temperature and high pressure conditions, while simultaneously removing ammonia nitrogen. It has become an important technological direction for the pretreatment of high-concentration chemical wastewater. However, traditional wet oxidation technology requires operation under harsh conditions above 200℃ and 3MPa, placing extremely high demands on the equipment's resistance to high temperatures, high pressures, and corrosion. Initial investment is large, and energy consumption remains high during operation, significantly increasing the operating costs of wastewater treatment. Low-temperature wet oxidation technology (<200℃) developed to reduce operating conditions alleviates equipment and energy consumption pressures, but due to insufficient oxidation reaction kinetics, it suffers from low oxidation efficiency and incomplete pollutant removal, making it unsuitable for the treatment needs of high-concentration chemical wastewater. Therefore, there is an urgent need to develop a low-temperature wet oxidation technology with high oxidation efficiency and high pollutant removal rate. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the shortcomings of the existing technology and provide a chemical wastewater treatment system based on catalytic wet oxidation reaction. Through the in-situ coupling design of hydraulic cavitation, micro-nano bubbles and catalytic wet oxidation, combined with a gradient catalyst bed and system energy recovery structure, high-concentration and recalcitrant chemical wastewater can be treated efficiently.

[0005] The technical solution of this utility model is as follows:

[0006] The chemical wastewater treatment system based on catalytic wet oxidation includes a pretreatment unit, a heat exchanger, a hydraulic cavitation device, a catalytic wet oxidation reactor, and a gas-liquid separator. The pretreatment unit is connected to the wastewater inlet of the heat exchanger via a pretreatment discharge pipeline. The wastewater outlet of the heat exchanger is connected to the inlet of the hydraulic cavitation device via a pipeline. The hydraulic cavitation device is also connected to a micro / nano bubble generator via a pipeline. The inlet of the micro / nano bubble generator is connected to a water inlet pipeline, through which an aqueous solution of oxidizing gas is introduced. The outlet of the hydraulic cavitation device is connected to the top inlet of the catalytic wet oxidation reactor via a cyclone generator. The catalytic wet oxidation reactor contains at least two stages of catalyst beds arranged from top to bottom, with the porosity of the catalyst beds decreasing sequentially from top to bottom and the catalyst activity increasing sequentially from top to bottom. The bottom outlet of the catalytic wet oxidation reactor is connected to the inlet of the gas-liquid separator via a pipeline. The liquid outlet of the gas-liquid separator is connected to the heat exchange medium inlet of the heat exchanger via a heat exchange pipeline.

[0007] Preferably, the pretreatment unit includes an adjustment tank.

[0008] Preferably, a feed pump is installed on the pretreatment discharge pipeline.

[0009] Preferably, the catalyst bed in the catalytic wet oxidation reactor is arranged in three stages from top to bottom: a primary catalyst bed, a secondary catalyst bed, and a tertiary catalyst bed. The primary catalyst bed has a porosity of 65% and a catalyst active component loading of 1-2 wt.%; the secondary catalyst bed has a porosity of 55% and a catalyst active component loading of 3-5 wt.%; and the tertiary catalyst bed has a porosity of 45% and a catalyst active component loading of 5-8 wt.%.

[0010] Preferably, a temperature sensor is installed at the top feed inlet of the catalytic wet oxidation reactor, and a regulating valve is installed on the heat exchange pipeline.

[0011] Preferably, the catalytic wet oxidation reactor is equipped with a temperature sensor and a pressure sensor.

[0012] Preferably, the hydraulic cavitation device employs a Venturi mixer, and the outlet of the micro-nano bubble generator is connected to the throat of the Venturi mixer.

[0013] This invention addresses the problems of low oxidation efficiency and incomplete pollutant removal in traditional wet oxidation treatment technologies for chemical wastewater. Through an in-situ coupling design of hydraulic cavitation, micro / nano bubbles, and catalytic wet oxidation, combined with a gradient catalyst bed and system energy recovery structure, it achieves highly efficient treatment of high-concentration, recalcitrant chemical wastewater. The overall beneficial effects are as follows:

[0014] 1. This invention couples in situ and in real time the mechanical pyrolysis and free radical generation of hydraulic cavitation, the efficient mass transfer and continuous oxygen supply of micro-nano bubbles, and the directional catalytic degradation of wet oxidation, forming a synergistic effect of "1+1+1>3". Hydraulic cavitation creates an activation environment for micro-nano bubbles and catalytic reactions, lowering the cavitation threshold and pyrolyzing large organic molecules; micro-nano bubbles, as "pre-fabricated cavitation nuclei", enhance cavitation efficiency and provide a continuous and stable oxygen supply for catalytic reactions, while their interfacial oxidation can supplement the free radical oxidation pathway; the catalytic reaction fully utilizes the activation energy and active species generated in the preceding steps to accelerate pollutant degradation. The triple effect superposition achieves efficient decomposition of recalcitrant organic matter and ammonia nitrogen, solving the problems of insufficient kinetics and incomplete degradation in traditional low-temperature wet oxidation reactions.

[0015] 2. This invention utilizes multiple oxidation pathways, including free radical oxidation, catalytic oxidation, and micro / nano bubble interface oxidation, to gradually break down recalcitrant macromolecular organic matter in wastewater into easily biodegradable small molecule organic matter. This significantly improves the B / C ratio of the wastewater, enabling high-concentration chemical wastewater that could not be directly treated biochemically to be directly connected to conventional biochemical treatment units after being treated by this invention's system. This achieves the standard degradation of the wastewater and opens up a complete treatment path of "advanced oxidation pretreatment + deep biochemical treatment".

[0016] 3. The catalytic wet oxidation reactor of this invention employs a gradient bed structure with decreasing porosity and increasing catalyst activity from top to bottom. The first-stage catalyst bed utilizes its low activity and high porosity characteristics to complete the initial cracking of large molecular organics using residual cavitation energy, reducing the energy barrier for subsequent reactions. The second-stage catalyst bed achieves deep oxidation of medium-molecular-weight organics. The third-stage catalyst bed, through its high activity and low porosity characteristics, thoroughly mineralizes recalcitrant small molecules. This staged degradation design allows for precise matching of the catalyst with different forms of pollutants, avoiding the degradation bottleneck of a single catalyst bed and improving catalyst utilization and overall catalytic oxidation efficiency.

[0017] 4. A swirl generator is added between the hydraulic cavitation device and the catalytic wet oxidation reactor of this utility model, so that the gas-liquid mixture forms a stable swirling state and flows spirally downward along the inner wall of the reactor. This allows the free radicals and micro-nano bubbles generated by cavitation to form a radial gradient distribution in the centrifugal force field, effectively avoiding the rapid quenching of active species, greatly extending their residence time in the reactor, ensuring that active species fully participate in the catalytic oxidation reaction, solving the problems of active species loss and bubble aggregation in non-in-situ coupling, and ensuring the full play of the system's synergistic effect.

[0018] 5. This utility model uses a Venturi mixer as a hydraulic cavitation device and directly connects the outlet of the micro-nano bubble generator to the throat of the Venturi mixer, integrating the cavitation effect and micro-nano bubble injection function into the pipeline. This eliminates the need for a large independent cavitation tank or a complex gas dispersion system, simplifying the process. At the same time, the various units of the system are connected in series through a closed pipeline, resulting in a compact overall structure, small footprint, and suitability for installation and application in industrial sites. It also facilitates the upgrading and transformation of existing wastewater treatment systems.

[0019] 6. This utility model utilizes the high-temperature effluent from the gas-liquid separator as the heat exchange medium of the heat exchanger to preheat the pretreated low-temperature chemical wastewater, thereby realizing the recovery and reuse of waste heat from the reaction within the system. This reduces the energy consumption of external heating sources, improves the system's energy utilization rate, meets the energy-saving and environmental protection requirements of industrial production, and further reduces the overall operating cost of wastewater treatment. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the chemical wastewater treatment system based on catalytic wet oxidation reaction according to this utility model.

[0021] In the diagram, 1. Pretreatment unit; 101. Pretreatment discharge pipeline; 2. Heat exchanger; 3. Venturi mixer; 301. Throat; 4. Catalytic wet oxidation reactor; 401. Primary catalyst bed; 402. Secondary catalyst bed; 403. Tertiary catalyst bed; 5. Gas-liquid separator; 501. Heat exchange pipeline; 6. Micro / nano bubble generator; 601. Water inlet pipeline; 7. Cyclone generator; 8. Feed pump; 9. Temperature sensor one; 10. Control valve; 11. Temperature sensor two; 12. Pressure sensor. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions of this utility model, the technical solutions of this utility model will be clearly and completely described below in conjunction with the embodiments of this utility model.

[0023] Example 1

[0024] like Figure 1 As shown, this embodiment provides a chemical wastewater treatment system based on catalytic wet oxidation reaction. The system is a closed-loop pipeline connection structure. The core includes a pretreatment unit 1, a heat exchanger 2, a hydraulic cavitation device, a catalytic wet oxidation reactor 4, and a gas-liquid separator 5. It is also equipped with a micro-nano bubble generator 6, a cyclone generator 7, and 10 sets of various sensors and regulating valves. The end is connected to the biochemical treatment unit and the waste gas treatment unit to realize the integrated and efficient treatment and resource recovery of chemical wastewater.

[0025] In this embodiment, the pretreatment unit 1 is an equalization tank with an effective volume of 50m³.3 The system is equipped with a stirring device and a level gauge, which can homogenize and regulate the flow of chemical wastewater, eliminating the impact of water quality and quantity fluctuations on subsequent treatment units. A screen filter is installed at the outlet of the equalization tank to intercept suspended impurities with a particle size greater than 5mm in the wastewater. The equalization tank is connected to the wastewater inlet of the heat exchanger 2 through a pretreatment discharge pipeline 101. A feed pump 8 is installed on the pretreatment discharge pipeline 101 to steadily pump the pretreated wastewater into the heat exchanger 2 for heat exchange.

[0026] Heat exchanger 2 is a shell-and-tube heat exchanger, with wastewater flowing through the tubes and the heat exchange medium flowing through the shell. The high-temperature effluent after subsequent gas-liquid separation is used to preheat the wastewater, realizing the recovery and utilization of system energy and reducing the energy consumption of external heating sources. The wastewater outlet of heat exchanger 2 is connected to the inlet of the hydraulic cavitation device through a pipeline. In this embodiment, the hydraulic cavitation device adopts a Venturi mixer 3 (inlet pipe diameter DN80, throat pipe 301 diameter DN12, contraction section cone angle 20°, diffuser section cone angle 8°). The wastewater preheated by heat exchanger 2 enters the Venturi mixer 3 and flows sequentially through the inlet section, contraction section, throat pipe 301, and diffuser section.

[0027] like Figure 1 As shown, the throat 301 of the Venturi mixer 3 is connected to the micro / nano bubble generator 6 via a pipeline. The inlet of the micro / nano bubble generator 6 is connected to a water inlet pipeline 601, through which an oxygen-saturated aqueous solution is introduced. The oxygen-saturated aqueous solution is delivered to the micro / nano bubble generator 6, where it is treated to form a micro / nano bubble water flow. At the throat 301 of the Venturi mixer 3, the flow velocity of the wastewater increases sharply and the pressure drops to a minimum, forming a negative pressure zone that rapidly draws in the micro / nano bubble water flow. The two fluids collide and mix thoroughly in the diffusion section, and as the pressure gradually recovers, a strong hydraulic cavitation effect is generated during this process, simultaneously achieving uniform fusion of micro / nano bubbles and wastewater.

[0028] like Figure 1 As shown, the outlet of the Venturi mixer 3 is connected to the cyclone generator 7 via a pipeline. The outlet of the cyclone generator 7 is connected to the top inlet of the catalytic wet oxidation reactor 4. The mixed gas-liquid fluid forms a stable cyclone feed after passing through the cyclone generator 7, and flows downward in a spiral shape along the inner wall of the catalytic wet oxidation reactor 4. This allows the free radicals and micro-nano bubbles generated by cavitation to achieve radial gradient distribution in the centrifugal force field, which greatly prolongs the effective residence time of active species in the catalytic wet oxidation reactor 4 and avoids the rapid quenching of active species.

[0029] In this embodiment, the catalytic wet oxidation reactor 4 is a vertical high-pressure reactor, such as... Figure 1 As shown, the catalyst bed in the catalytic wet oxidation reactor 4 is arranged in three stages from top to bottom, with a height ratio of 2:3:1. Wherein:

[0030] Primary catalyst bed 401: porosity 65%, catalyst active component loading 2wt.%, mainly utilizes residual cavitation energy to perform preliminary cracking of macromolecular organic matter in wastewater, reducing the energy barrier of subsequent oxidation reactions.

[0031] Secondary catalyst bed 402: porosity 55%, catalyst active component loading 4wt.%, for deep oxidation and decomposition of medium molecular weight organic matter after primary cracking;

[0032] The tertiary catalyst bed 403 has a porosity of 45% and a catalyst active component loading of 6 wt.%, which thoroughly mineralizes recalcitrant small molecule organic matter and decomposes it into inorganic products such as CO2 and H2O.

[0033] like Figure 1 As shown, a temperature sensor 9 is installed at the top inlet of the catalytic wet oxidation reactor 4 to monitor the temperature of the fluid entering the reactor 4 in real time; a regulating valve 10 is installed on the heat exchange pipeline 501 to adjust the flow rate of the heat exchange medium according to the temperature monitoring data. A temperature sensor 11 and a pressure sensor 12 are installed inside the catalytic wet oxidation reactor 4 to monitor the reaction temperature and pressure inside the reactor 4 in real time, and to stably control the reaction conditions at 175℃ and 2MPa.

[0034] like Figure 1 As shown, the bottom outlet of the catalytic wet oxidation reactor 4 is connected to the inlet of the gas-liquid separator 5 via a pipeline to achieve gas-liquid separation of the fluid. The liquid outlet of the gas-liquid separator 5 is connected to the heat exchange medium inlet of the heat exchanger 2 via a heat exchange pipeline 501. The separated high-temperature effluent enters the heat exchanger 2 as the heat exchange medium to preheat the pretreated low-temperature wastewater, achieving efficient heat recovery of the system and reducing energy waste.

[0035] The heat exchange medium outlet of heat exchanger 2 is connected to the biochemical treatment unit via a pipeline, and the effluent after heat exchange enters the biochemical treatment unit for further degradation; the gas outlet of gas-liquid separator 5 is connected to the waste gas treatment unit via a pipeline, and the separated gaseous products are discharged after meeting the standards in the waste gas treatment unit. Both the biochemical treatment unit and the waste gas treatment unit use existing mature treatment equipment, which will not be described in detail here.

[0036] The chemical wastewater treatment method of this embodiment specifically includes the following steps:

[0037] S1 Pretreatment and Preheating

[0038] After being homogenized and equalized in the equalization tank and impurities are intercepted by the screen, the chemical wastewater is transported by the feed pump 8 at a pressure of 2MPa and enters the tube side of the shell-and-tube heat exchanger 2 to exchange heat with the high-temperature effluent from the gas-liquid separator 5 in the shell side, thus completing the preheating.

[0039] S2 In-situ Coupling of Hydraulic Cavitation and Micro / Nano Bubbles

[0040] The preheated wastewater flows through the Venturi mixer 3 at a pressure of 2 MPa, generating a strong hydraulic cavitation effect at the throat 301, creating a localized high-temperature and high-pressure environment. Water molecules break down to produce a large number of active free radicals, while simultaneously generating strong microjets and shear forces. At the same time, an oxygen-saturated aqueous solution rich in micro-nano bubbles, generated by the micro-nano bubble generator 6, is directly injected into the core region of the water flow undergoing hydraulic cavitation through the throat 301 of the Venturi mixer 3. The two processes have a significant synergistic effect.

[0041] 1) Cavitation pretreatment effect: The microjets and shear forces generated by hydraulic cavitation directly break down large molecular organic matter in wastewater into small molecular intermediates, thereby reducing the energy barrier of subsequent catalytic oxidation reactions.

[0042] 2) Micro-nano bubble cavitation nucleus effect: Micro-nano bubbles, as "pre-fabricated cavitation nuclei", significantly reduce the threshold of hydraulic cavitation, improve cavitation intensity and cavitation efficiency, and micro-nano bubbles collapse in the cavitation environment, generating secondary oxidation, which further increases the concentration of active free radicals;

[0043] 3) In-situ mass transfer enhancement effect: The micro-jet and micro-stirring effect generated by cavitation greatly enhances the contact and mass transfer efficiency between micro-nano bubbles and organic matter in wastewater and the surface of subsequent catalyst beds.

[0044] S3 catalytic wet oxidation reaction

[0045] The gas-liquid mixture, after being treated by the Venturi mixer 3, carries high-density micro-nano bubbles, high-concentration active free radicals, and activated organic molecules. After being swirled by the vortex generator 7, it enters the catalytic wet oxidation reactor 4 from the top, spiraling downwards along the inner wall and passing sequentially through a three-stage catalyst bed 403. Under mild operating conditions of 175℃ and 2MPa, utilizing dissolved oxygen in the wastewater and oxygen continuously released from the micro-nano bubbles, a highly efficient catalytic wet oxidation reaction occurs under the catalytic action of the catalyst: the primary catalyst bed 401 completes macromolecular cleavage, the secondary catalyst bed 402 completes medium-molecular oxidation, and the tertiary catalyst bed 403 completes deep mineralization. The long residence time of the micro-nano bubbles provides a continuous and stable supply of oxidant for the catalytic oxidation reaction, and the active free radicals generated by hydraulic cavitation further accelerate the catalytic wet oxidation process, achieving efficient degradation of recalcitrant organic matter.

[0046] S4 Gas-Liquid Separation, Energy Recovery and Subsequent Processing

[0047] The gas-liquid mixture after the catalytic wet oxidation reaction is discharged from the bottom and enters the gas-liquid separator 5 to achieve effective separation of the gas and liquid phases. The high-temperature effluent after separation enters the heat exchanger 2 as a heat exchange medium to exchange heat with the pretreated low-temperature wastewater. After energy recovery, it enters the biochemical treatment unit for further degradation. The separated gas is discharged after meeting the standards in the waste gas treatment unit, achieving simultaneous treatment of wastewater and waste gas to meet the standards.

[0048] Example 2

[0049] This embodiment utilizes the chemical wastewater treatment system from Example 1 to treat high-concentration organic wastewater from a pesticide intermediate production enterprise. The system operating parameters and treatment results are as follows:

[0050] The catalyst uses CuO and Fe2O3 composite oxide supported on Al2O3 (Shandong Longantai Environmental Protection Technology Co., Ltd.).

[0051] Raw water quality indicators: COD=15000mg / L, ammonia nitrogen content=800mg / L, B / C=0.15.

[0052] System treatment results: effluent COD decreased to 1800 mg / L, removal rate 88%; ammonia nitrogen content decreased to 120 mg / L, removal rate 85%; B / C ratio increased to 0.52.

[0053] Comparative Example 1

[0054] The difference from Example 2 is that the micro / nano bubble generator 6 is turned off. The processing conditions are the same as in Example 2.

[0055] Treatment results: effluent COD decreased to 10200 mg / L, removal rate 32%; ammonia nitrogen content decreased to 358 mg / L, removal rate 55%; B / C ratio increased to 0.22.

[0056] Comparing Example 2 with Comparative Example 1, it can be seen that hydraulic cavitation alone can only break down a small amount of large-molecule organic matter through mechanical shearing and local cavitation effects, and cannot provide a continuous supply of oxidant. It has no effective degradation effect on recalcitrant organic matter and ammonia nitrogen in wastewater. Moreover, the active free radicals generated by cavitation are easily quenched quickly and cannot form a continuous oxidation capacity. The improvement of the biodegradability of wastewater is limited, and subsequent biochemical treatment is difficult. This proves that the injection of micro-nano bubbles is the key to achieving efficient oxidative degradation.

[0057] Comparative Example 2

[0058] The difference from Example 2 is that the outlet of the Venturi mixer 3 is directly connected to the top inlet of the catalytic wet oxidation reactor 4 via a pipeline, and the transmission time is controlled within 10 seconds. The processing conditions are the same as in Example 2.

[0059] Treatment results: effluent COD decreased to 5850 mg / L, removal rate 61%; ammonia nitrogen content decreased to 389 mg / L, removal rate 51%; B / C ratio increased to 0.33.

[0060] Comparing Example 2 with Comparative Example 2 reveals that the in-situ coupling of cavitation and micro / nano bubbles causes a significant amount of active free radicals generated in the Venturi mixer 3 to be quenched during pipeline transport. Furthermore, the micro / nano bubbles coalesce during transport, increasing their particle size and drastically reducing stability and mass transfer efficiency. This results in a substantial decrease in the content of active species and effective oxidant entering the catalytic wet oxidation reactor 4, leading to a significant drop in catalytic oxidation reaction efficiency. Simultaneously, without the swirling feed effect of the swirling generator 7, the residence time of active species in the catalytic wet oxidation reactor 4 is significantly shortened, further reducing the treatment effect. This demonstrates that in-situ coupling combined with swirling stabilization is the core design element ensuring the system's synergistic effect.

Claims

1. A chemical wastewater treatment system based on catalytic wet oxidation reaction, characterized in that, The system includes a pretreatment unit (1), a heat exchanger (2), a hydraulic cavitation device, a catalytic wet oxidation reactor (4), and a gas-liquid separator (5). The pretreatment unit (1) is connected to the wastewater inlet of the heat exchanger (2) via a pretreatment discharge pipeline (101). The wastewater outlet of the heat exchanger (2) is connected to the inlet of the hydraulic cavitation device via a pipeline. The hydraulic cavitation device is also connected to a micro / nano bubble generator (6) via a pipeline. The inlet of the micro / nano bubble generator (6) is connected to a water inlet pipeline (601). Oxidizing gas water solution is introduced into the water inlet pipeline (601). The outlet of the hydraulic cavitation device is connected to the top inlet of the catalytic wet oxidation reactor (4) via a cyclone generator (7). The catalytic wet oxidation reactor (4) has at least two stages of catalyst beds arranged from top to bottom. The porosity of the catalyst beds decreases from top to bottom and the catalyst activity increases from top to bottom. The bottom outlet of the catalytic wet oxidation reactor (4) is connected to the inlet of the gas-liquid separator (5) via a pipeline. The liquid outlet of the gas-liquid separator (5) is connected to the heat exchange medium inlet of the heat exchanger (2) via a heat exchange pipeline (501).

2. The chemical wastewater treatment system based on catalytic wet oxidation reaction as described in claim 1, characterized in that, The pretreatment unit (1) includes an adjustment tank.

3. The chemical wastewater treatment system based on catalytic wet oxidation reaction as described in claim 1, characterized in that, A feed pump (8) is installed on the pretreatment discharge pipeline (101).

4. The chemical wastewater treatment system based on catalytic wet oxidation reaction as described in claim 1, characterized in that, The catalyst bed in the catalytic wet oxidation reactor (4) is arranged in three stages from top to bottom: a primary catalyst bed (401), a secondary catalyst bed (402), and a tertiary catalyst bed (403). The primary catalyst bed (401) has a porosity of 65% and a catalyst active component loading of 1-2 wt.%; the secondary catalyst bed (402) has a porosity of 55% and a catalyst active component loading of 3-5 wt.%; and the tertiary catalyst bed (403) has a porosity of 45% and a catalyst active component loading of 5-8 wt.%.

5. The chemical wastewater treatment system based on catalytic wet oxidation reaction as described in claim 1, characterized in that, A temperature sensor (9) is installed at the top feed inlet of the catalytic wet oxidation reactor (4), and a regulating valve (10) is installed on the heat exchange pipeline (501).

6. The chemical wastewater treatment system based on catalytic wet oxidation reaction as described in claim 5, characterized in that, The catalytic wet oxidation reactor (4) is equipped with a temperature sensor (11) and a pressure sensor (12).

7. The chemical wastewater treatment system based on catalytic wet oxidation reaction as described in claim 5, characterized in that, The hydraulic cavitation device uses a Venturi mixer (3), and the outlet of the micro-nano bubble generator (6) is connected to the throat (301) of the Venturi mixer (3).

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