Zero-discharge process system and method for cutting waste liquid

Abstract

The invention provides a zero-discharge process system and method for cutting waste liquid, and belongs to the technical field of green manufacturing. The system comprises a pretreatment unit, a low-temperature evaporation and concentration unit, a high-temperature oxidative degradation unit and a resource utilization unit. According to the system, the cutting waste liquid is subjected to multi-stage separation, low-temperature evaporation concentration, high-temperature oxidative degradation and resource recovery, so that full-process harmless treatment of the waste liquid and efficient recycling of resources are realized, and'zero emission 'of waste water, waste oil, waste residues and waste gas is really realized.

Description

Technical Field

[0001] This application belongs to the field of green manufacturing technology, specifically relating to a zero-discharge process system and method for cutting waste fluid. Background Technology

[0002] Cutting fluid, an indispensable process medium in the machining industry, plays a crucial role in lubrication, cooling, cleaning, and rust prevention. However, during its use, it becomes contaminated with large amounts of lubricating oil, hydraulic oil, metal shavings, grinding debris, and bacteria, gradually deteriorating and forming complex and difficult-to-treat cutting waste fluids. These waste fluids typically exhibit high chemical oxygen demand (COD), high oil content, and heavy metal content. Direct discharge without treatment can cause serious pollution to water bodies and soil, harming the ecological environment and human health. Therefore, effective treatment of cutting waste fluids is a critical issue that the machining industry must address to achieve green and sustainable development.

[0003] Currently, the main methods for treating cutting fluids include physical, chemical, and biological methods. Physical methods, such as sedimentation, centrifugation, and filtration, are commonly used to remove suspended solids and some floating oil, but they are difficult to treat emulsified oils and dissolved contaminants. Chemical methods, such as coagulation sedimentation, demulsification, and advanced oxidation, can break down emulsion systems and degrade some organic matter, but they often require the addition of chemicals, which may cause secondary pollution, and the operating costs are high. Biological methods utilize microorganisms to degrade organic matter, but the treatment cycle is long, and the system has limited tolerance to toxic substances and poor operational stability. Most of the above traditional methods have disadvantages such as incomplete treatment, low resource recovery rates, and easy generation of secondary pollution or sludge, making it difficult to meet the increasingly stringent environmental regulations and the construction requirements of "zero-waste factories."

[0004] With the deepening of the circular economy concept, the treatment of industrial waste has shifted from simple end-of-pipe treatment to a combination of pollution control and resource utilization throughout the entire process. Existing treatment technologies and systems often focus on harmlessness, failing to systematically recover and recycle water, oil, valuable metals, and energy and substances (such as carbon dioxide) generated during the reaction process, thus failing to truly achieve resource utilization of waste and "zero emissions" in the treatment process. Therefore, developing a new cutting fluid treatment process system that integrates multiple technological advantages, achieves deep integration of harmless treatment and resource utilization, and ultimately reaches the goal of zero emissions, has an extremely urgent practical need and broad application prospects. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to overcome the shortcomings of existing cutting fluid treatment technologies and provide a high-efficiency, environmentally friendly, and resource-recovery-rate zero-discharge treatment system and method for cutting fluid, which can effectively separate and utilize the three phases of water, oil, and solid in the waste fluid, reduce external emissions, and improve the economy and sustainability of the treatment process.

[0006] The present invention provides a zero-emission process system for the harmless treatment and resource utilization of cutting waste fluid, comprising the following implementation steps: Pretreatment stage: Waste liquid is transported from raw liquid tank 1 to pre-filter 3 via raw liquid transfer pump 2 to remove large particulate impurities and floating oil, and then enters water-oil-solid three-phase separator 4 for oil, water and solid three-phase separation.

[0007] Low-temperature evaporation and concentration stage: The aqueous phase enters the demulsifier 5 via the on / off valve V1. After demulsification, it is sent to the relay tank 7 via the demulsifier transfer pump 6, and then to the low-temperature evaporator 9 for first-stage treatment and concentration by the evaporator transfer pump 8. The concentrated liquid enters the concentrated liquid tank 11, and the distilled water enters the greywater storage tank 24 after passing through the precision filter 10.

[0008] High-temperature oxidation degradation stage: After the oil phase and concentrate are mixed in the concentrate tank 11, they are transported by the high-pressure material pump 12 and heated sequentially through the preheater 13 and the regenerator 14 before entering the high-temperature oxidation reactor 15 for reaction. After the reaction, the high-temperature fluid is cooled by the regenerator 14 and the condenser 17, and then depressurized by the pressure reducer 18 before entering the gas-liquid-solid three-phase separator 19 for separation.

[0009] Resource utilization stage: Gaseous CO2 enters the microalgae carbon fixation tank 21; liquid phase enters the greywater storage tank 24; solid metal scraps enter the collection tank 25. Steam generated by the cooling water system enters the steam storage tank 23, which can be used for external heating or further utilization.

[0010] Compared with the prior art, the present invention has the following beneficial technical effects: This invention provides a zero-emission process system and method for the harmless treatment and resource utilization of cutting fluid. By integrating a pretreatment unit, a low-temperature evaporation and concentration unit, a high-temperature oxidation and degradation unit, and a resource utilization unit, a complete system for the full-process treatment and resource recovery of cutting fluid is constructed. Based on a technical approach combining multi-stage separation, evaporation and concentration, and high-temperature oxidation and degradation, efficient separation and harmless treatment of the oil, water, and solid phases in the waste fluid are achieved. Furthermore, the treated products are innovatively converted into reusable water resources, metal raw materials, and carbon dioxide resources. Compared to existing technologies, this invention completely solves the technical bottlenecks of incomplete cutting fluid treatment, severe secondary pollution, and low resource recovery rates. It not only significantly reduces the environmental risks during waste fluid treatment and eliminates the emission of harmful substances, but also achieves near-zero energy consumption and resource value-added through energy cascade utilization and material recycling. Simultaneously, the system possesses good engineering applicability and automation levels, improving overall economic efficiency while achieving environmental benefits, providing key technical support for the green upgrading of the machining industry. Attached Figure Description

[0011] Figure 1This is a schematic diagram of a zero-discharge process system for cutting waste fluid; The components include: 1. Raw material tank; 2. Raw material transfer pump; 3. Pre-filter; 4. Water-oil-solid three-phase separator; 5. Demulsifier; 6. Demulsifier transfer pump; 7. Relay tank; 8. Evaporator transfer pump; 9. Low-temperature evaporator; 10. Precision filter; 11. Concentrate tank; 12. High-pressure material pump; 13. Preheater; 14. Regenerator; 15. High-temperature oxidation reactor; 16. Cooling water jacket; 17. Condenser; 18. Pressure reducer; 19. Gas-liquid-solid three-phase separator; 20. Cutting fluid recycling tank; 21. Microalgae carbon fixation box; 22. Circulating cooling water tank; 23. Steam storage tank; 24. Greywater storage tank; 25. Metal scrap collection box; V1 switch valve; and V2 switch valve. Detailed Implementation

[0012] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0013] This invention provides a zero-emission process system for the harmless treatment and resource utilization of cutting waste fluid, such as... Figure 1 As shown, it includes a pretreatment unit, a low-temperature evaporation and concentration unit, a high-temperature oxidation and degradation unit, and a resource utilization unit.

[0014] The pretreatment unit consists of a raw liquid tank, a raw liquid transfer pump, a pre-filter, and a water-oil-solid three-phase separator. The inlet of the waste liquid raw liquid transfer pump is connected to the outlet of the waste liquid raw liquid tank, and the outlet is connected to the inlet of the pre-filter. The outlet of the pre-filter is connected to the inlet of the water-oil-solid three-phase separator. The water-oil-solid three-phase separator has four outlets: two liquid phase outlets are connected to the resource utilization unit and the low-temperature evaporation and concentration unit, respectively; one solid phase outlet is connected to the resource utilization unit; and one oil phase outlet is connected to the high-temperature oxidation and degradation unit. The low-temperature evaporation and concentration unit consists of a demulsifier, a demulsifier transfer pump and a relay tank, an evaporator delivery pump, a low-temperature evaporator, a precision filter, and a switching valve V1. The inlet of the low-temperature evaporation and concentration unit is connected to one of the liquid phase outlets of the pretreatment unit via the switching valve V1. Specifically, the inlet and outlet of the switching valve V1, the inlet and outlet of the demulsifier, the inlet and outlet of the demulsifier transfer pump, the inlet and outlet of the relay tank, the inlet and outlet of the evaporator delivery pump, and the inlet of the low-temperature evaporator are connected sequentially. The low-temperature evaporator has two outlets: one concentrated liquid outlet connected to the high-temperature oxidation and degradation unit, and one distilled water outlet connected to the precision filter inlet. The precision post-filter outlet is connected to the resource utilization unit. The high-temperature oxidation degradation unit consists of a concentrate tank, a high-pressure material pump, a preheater, a regenerator, a high-temperature oxidation reactor, a cooling water jacket, a condenser, a pressure reducer, and a gas-liquid-solid three-phase separator. The inlet of the high-temperature oxidation degradation unit is connected to the oil phase outlet of the water-oil-solid three-phase separator and the concentrate outlet of the low-temperature evaporator via the concentrate tank. Specifically, the inlet and outlet of the concentrate tank, the inlet and outlet of the high-pressure material pump, the inlet and outlet of the preheater, the inlet and outlet of the low-temperature waste liquid of the regenerator, the inlet and outlet of the high-temperature oxidation reaction material, the inlet and outlet of the high-temperature water outlet of the regenerator, the inlet and outlet of the high-temperature water outlet of the condenser, the inlet and outlet of the pressure reducer, and the inlet of the gas-liquid-solid three-phase separator are connected sequentially. The gas-liquid-solid three-phase separator has three outlets: one gas phase outlet, one liquid phase outlet, and one solid phase outlet, all of which are connected to the resource utilization unit. The resource utilization unit consists of a cooling water jacket, a condenser, a cutting fluid recycling unit, a microalgae carbon fixation box, a circulating cooling water box, a steam storage tank, a greywater storage tank, a metal scrap collection box, and a switching valve V2. The resource utilization unit has a total of 8 inlets, which are connected to the solid-liquid two-phase outlet of the water-oil-solid three-phase separator, the gas-liquid-solid three-phase outlet of the gas-liquid-solid three-phase separator, the precision filter outlet, the cooling water jacket outlet, and the condenser cooling water outlet, respectively. Among them, the cutting fluid recycling tank is connected to the liquid phase outlet of the water-oil-solid three-phase separator in the pretreatment unit through the switching valve V2; the microalgae carbon fixation box inlet is connected to the gas phase outlet of the gas-liquid-solid three-phase separator; the circulating cooling water tank has 2 outlets connected to the cooling water jacket inlet and the condenser cooling water inlet, respectively; the steam storage tank has 2 inlets connected to the cooling water jacket outlet and the condenser cooling water outlet, respectively; the greywater storage tank has 2 inlets connected to the precision filter outlet and the liquid phase outlet of the gas-liquid-solid three-phase separator, respectively; and the metal scrap collection box has 2 inlets connected to the solid phase outlet of the water-oil-solid three-phase separator and the solid phase outlet of the gas-liquid-solid three-phase separator, respectively.

[0015] The water-oil-solid three-phase separator has a total of 4 outlets. There are 2 liquid phase outlets, one of which is connected to the inlet of the demulsifier tank via switch valve V1, and the other is connected to the inlet of the cutting fluid recycling tank via switch valve V2; there is 1 oil phase outlet, which is connected to the inlet of the concentrate tank; and there is 1 solid phase outlet, which is connected to the inlet of the metal scrap collection box.

[0016] The high-temperature oxidation reactor has two inlets, one for the oxidant and the other for the high-temperature material. A cooling water jacket is installed on the outer wall of the high-temperature oxidation reactor and is coaxial with the outer wall. The inlet is located at the bottom of the water jacket and the outlet is located at the top of the water jacket.

[0017] The regenerator is a shell-and-tube heat exchanger through which two fluids pass. One is the effluent after high-temperature oxidation and degradation, which enters the outer tube section; the other is the preheated waste liquid, which enters the inner tube section via the preheater.

[0018] The zero-emission process system for harmless treatment and resource utilization of cutting waste fluid is characterized in that the condenser is a shell-and-tube heat exchanger through which two fluids pass. One fluid is water that has been oxidized and degraded at high temperature and enters the high-pressure side pipe section after reheating. The other fluid is circulating cooling water that enters the low-pressure side pipe section from the circulating cooling water tank.

[0019] This invention also discloses a zero-emission process for the harmless treatment and resource utilization of cutting waste fluid, comprising the following steps: 1) The raw cutting fluid waste is stored in the raw fluid tank. After being pumped by the raw fluid transfer pump, it enters the pre-filter to filter out large-sized residues and surface oil. Then, it enters the water-oil-solid three-phase separator to separate the oil, liquid, and solid phases. The liquid phase is tested. If it meets the cutting fluid operation quality requirements, it is stored in the cutting fluid reuse tank by closing valve V1 and opening valve V2. If it does not meet the cutting fluid operation quality requirements, it enters the low-temperature evaporation and concentration unit for primary volume reduction treatment by closing valve V2 and opening valve V1. The oil phase is stored in the concentrate tank, and the solid metal chips are stored in the metal chip collection box for metal chip recycling. 2) Switch valve V1 is normally open and switch valve V2 is normally closed. Only when the quality test of the liquid phase material in the water-oil-solid three-phase separator meets the reuse requirements, switch valves V1 and V2 are switched to start the cutting fluid reuse bypass. 3) The liquid waste entering the low-temperature evaporation and concentration unit passes through the demulsifier tank for demulsification, the demulsifier transfer pump for transportation, and the relay tank for buffering. Then, it enters the low-temperature evaporator for treatment via the evaporator transfer pump. The treated distilled water enters the precision filter for secondary filtration and is then stored in the greywater storage tank for use in the preparation of new cutting fluid. The remaining concentrate after treatment in the low-temperature evaporator enters the concentrate tank for storage and will subsequently enter the high-temperature oxidation degradation unit for further harmless treatment. 4) The oil phase from the water-oil-solid three-phase separator and the concentrate from the low-temperature evaporator are stored in the concentrate tank. They are then pressurized and transported to the preheater by a high-pressure material pump to complete the preheating and temperature rise. After that, they enter the outer pipe section of the regenerator and are further heated to the target temperature before entering the high-temperature oxidation reactor. There, they react with the oxidant and are oxidized and degraded into harmless small molecule components such as H2O and CO2. 5) After high-temperature oxidation treatment, the effluent enters the inner tube section of the regenerator to release heat and cool down. Then, it enters the high-pressure side tube section of the condenser for further cooling to room temperature. After being depressurized to atmospheric pressure by the pressure reducer, it enters the gas-liquid-solid three-phase separator to separate into gas, liquid, and solid products. The gas phase (mainly CO2) product enters the microalgae carbon fixation tank for algae slurry cultivation and external sales; the liquid phase product enters the greywater storage tank for storage and is used to prepare new cutting fluid; the solid phase product, metal scrap, enters the metal scrap collection tank for storage and is used for metal scrap recycling. 6) Part of the circulating cooling water enters the bottom of the cooling water jacket to cool and protect the wall of the high-temperature oxidation reactor. The heat-absorbing cooling water turns into steam and enters the steam storage tank from the top of the cooling water tank for storage. The other part enters the condenser shell side to cool the water after the high-temperature reaction. The heat-absorbing cooling water turns into steam and enters the steam storage tank from the top of the cooling water tank for storage. The steam in the steam storage tank is sold externally.

[0020] The entire system uses an intelligent control system to automatically adjust parameters such as valves, pumps, temperature, and pressure, ensuring efficient, stable, and safe processing.

Claims

1. A zero-discharge process system for cutting waste fluid, characterized in that, The process system includes a pretreatment unit, a low-temperature evaporation and concentration unit, a high-temperature oxidation and degradation unit, and a resource utilization unit. 1) Pretreatment stage: The waste liquid is separated into oil, water and solid phases through the pretreatment unit; 2) Low-temperature evaporation and concentration stage: The aqueous phase is concentrated by low-temperature evaporation in this stage; 3) High-temperature oxidative degradation stage: The oil phase is subjected to high-temperature oxidative degradation. 4) Resource utilization stage: The gas phase is reused through the resource utilization stage.

2. The zero-discharge process system for cutting waste fluid according to claim 1, characterized in that, The pretreatment unit consists of a raw liquid tank (1), a raw liquid transfer pump (2), a pre-filter (3), and a water-oil-solid three-phase separator (4). The inlet of the waste liquid raw liquid transfer pump (2) is connected to the outlet of the waste liquid raw liquid tank (1), and the outlet is connected to the inlet of the pre-filter (3). The outlet of the pre-filter (3) is connected to the inlet of the water-oil-solid three-phase separator (4). The water-oil-solid three-phase separator (4) has a total of 4 outlets, of which 2 liquid phase outlets are connected to the resource utilization unit and the low-temperature evaporation and concentration unit, respectively, 1 solid phase outlet is connected to the resource utilization unit, and 1 oil phase outlet is connected to the high-temperature oxidation and degradation unit.

3. The zero-discharge process system for cutting waste fluid according to claim 2, characterized in that, The low-temperature evaporation and concentration unit consists of a demulsifier (5), a demulsifier transfer pump (6), a relay tank (7), an evaporator transfer pump (8), a low-temperature evaporator (9), a precision filter (10), and a switching valve V1. The inlet of the low-temperature evaporation and concentration unit is connected to one of the liquid phase outlets of the pretreatment unit through the switching valve V1. The inlet and outlet of the switching valve V1, the inlet and outlet of the demulsifier (5), the inlet and outlet of the demulsifier transfer pump (6), the inlet and outlet of the relay tank (7), the inlet and outlet of the evaporator transfer pump (8), and the inlet of the low-temperature evaporator (9) are connected in sequence. The low-temperature evaporator (9) has two outlets: one concentrated liquid outlet is connected to the high-temperature oxidation and degradation unit, and one distilled water outlet is connected to the inlet of the precision filter (10). The outlet of the precision post-filter (10) is connected to the resource utilization unit.

4. The zero-discharge process system for cutting waste fluid according to claim 3, characterized in that, The high-temperature oxidation degradation unit consists of a concentrate tank (11), a high-pressure material pump (12), a preheater (13), a regenerator (14), a high-temperature oxidation reactor (15), a condenser (17), a pressure reducer (18), and a gas-liquid-solid three-phase separator (19). The inlet of the high-temperature oxidation degradation unit is connected to the oil phase outlet of the water-oil-solid three-phase separator (4) and the concentrate outlet of the low-temperature evaporator (9) through the concentrate tank (11). The inlet and outlet of the concentrate tank (11) and the inlet of the high-pressure material pump (12) are connected to the oil phase outlet of the water-oil-solid three-phase separator (4) and the concentrate outlet of the low-temperature evaporator (9). The inlet and outlet of the preheater (13), the inlet and outlet of the regenerator (14), the inlet and outlet of the low-temperature waste liquid, the inlet and outlet of the high-temperature oxidation reactor (15), the inlet and outlet of the regenerator (14), the inlet and outlet of the high-temperature water outlet, the inlet and outlet of the condenser (17), the inlet and outlet of the high-temperature water outlet, the inlet and outlet of the pressure reducer (18), and the inlet of the gas-liquid-solid three-phase separator (19) are connected in sequence; the gas-liquid-solid three-phase separator (19) has a total of 3 outlets, of which 1 gas phase outlet, 1 liquid phase outlet and 1 solid phase outlet are all connected to the resource utilization unit.

5. The zero-discharge process system for cutting waste fluid according to claim 4, characterized in that, The resource utilization unit consists of a cooling water jacket (16), a cutting fluid recycling tank (20), a microalgae carbon fixation box (21), a circulating cooling water tank (22), a steam storage tank (23), a greywater storage tank (24), a metal scrap collection box (25), and a switch valve V2. The resource utilization unit has a total of 8 inlets, which are respectively connected to the solid-liquid two-phase outlet of the water-oil-solid three-phase separator (4), the gas-liquid-solid three-phase outlet of the gas-liquid-solid three-phase separator (19), the outlet of the precision filter (10), the outlet of the cooling water jacket (16), and the cooling water outlet of the condenser (17). Among them, the cutting fluid recycling tank (20) is connected to the liquid water of the water-oil-solid three-phase separator (4) in the pretreatment unit through the switch valve V2. The inlet of the microalgae carbon fixation box (21) is connected to the gas phase outlet of the gas-liquid-solid three-phase separator (19). The two outlets of the circulating cooling water tank (22) are connected to the inlet of the cooling water jacket (16) and the cooling water inlet of the condenser (17), respectively. The two inlets of the steam storage tank (23) are connected to the outlet of the cooling water jacket (16) and the cooling water outlet of the condenser (17), respectively. The two inlets of the greywater storage tank (24) are connected to the outlet of the precision filter (10) and the liquid phase outlet of the gas-liquid-solid three-phase separator (19), respectively. The two inlets of the metal scrap collection box (25) are connected to the solid phase outlet of the water-oil-solid three-phase separator (4) and the solid phase outlet of the gas-liquid-solid three-phase separator (19), respectively.

6. The zero-discharge process system for cutting waste fluid according to claim 2, characterized in that, The water-oil-solid three-phase separator (4) has a total of 4 outlets. There are 2 liquid phase outlets, one of which is connected to the inlet of the demulsifier (5) through the switch valve V1, and the other is connected to the inlet of the cutting fluid recycling tank (20) through the switch valve V2. There is 1 oil phase outlet, which is connected to the inlet of the concentrate tank (11). There is 1 solid phase outlet, which is connected to the inlet of the metal scrap collection box (25).

7. The zero-discharge process system for cutting waste fluid according to claim 2, characterized in that, The high-temperature oxidation reactor (15) has two inlets, one of which is the oxidant inlet and the other is the high-temperature material inlet; the cooling water jacket (16) is set on the outer wall of the high-temperature oxidation reactor (15), coaxial with the outer wall of the high-temperature oxidation reactor (15), with the inlet set at the bottom of the water jacket and the outlet set at the top of the water jacket.

8. The zero-discharge process system for cutting waste fluid according to claim 2, characterized in that, The regenerator (14) is a shell-and-tube heat exchanger through which two fluids pass. One of them is the effluent after high-temperature oxidation and degradation, which enters the outer tube section; the other is the preheated waste liquid, which enters the inner tube section through the preheater (13). The condenser (17) is a shell-and-tube heat exchanger through which two fluids pass. One is water that has been oxidized and degraded at high temperature and enters the high-pressure side pipe section via the regenerator (14); the other is circulating cooling water that enters the low-pressure side pipe section from the circulating cooling water tank (22).

9. A zero-discharge process system for cutting waste fluid according to claim 2, characterized in that, The gas-liquid-solid three-phase separator (19) has three outlets: one gas outlet, which is connected to the inlet of the microalgae carbon fixation box (21); one liquid outlet, which is connected to the inlet of the greywater storage tank (24); and one solid outlet, which is connected to the inlet of the metal scrap collection box (25).

10. A zero-discharge process method for cutting waste fluid, said method being applied to the process system as described in any one of claims 1-9, characterized in that, Includes the following steps: 1) The raw cutting fluid waste liquid is stored in the raw liquid tank (1), and after passing through the raw liquid transfer pump (2), it enters the pre-filter (3) to filter out large-sized residues and surface oil. Then it enters the water-oil-solid three-phase separator (4) for oil, liquid and solid phase separation. The liquid phase material is tested. If it meets the cutting fluid operation quality requirements, it enters the cutting fluid recycling tank (20) for storage by closing the switch valve V1 and opening the switch valve V2 for cutting fluid recycling. If it does not meet the cutting fluid operation quality requirements, it enters the low temperature evaporation and concentration unit for primary volume reduction treatment by closing the switch valve V2 and opening the switch valve V1. The oil phase enters the concentrate tank (11) for storage, and the solid phase metal chips enter the metal chip collection box (25) for storage for metal chip recycling. 2) Switch valve V1 is normally open and switch valve V2 is normally closed. Only when the quality test of the liquid phase material in the water-oil-solid three-phase separator (4) meets the reuse requirements, switch valves V1 and V2 are switched to start the cutting fluid reuse bypass. 3) The liquid waste liquid entering the low-temperature evaporation and concentration unit passes through the demulsifier (5) for demulsification, the demulsifier transfer pump (6) for transportation, and the relay tank (7) for buffering. Then, it enters the low-temperature evaporator (9) through the evaporator transfer pump (8) for treatment. The treated distilled water enters the precision filter (10) for secondary filtration and is then stored in the greywater storage tank (24) for use in the preparation of new cutting fluid. The remaining concentrate after being processed by the low-temperature evaporator (9) is stored in the concentrate tank (11) and will be further treated in the high-temperature oxidation degradation unit to render it harmless. 4) The oil phase from the water-oil-solid three-phase separator (4) and the concentrate from the low-temperature evaporator (9) are stored in the concentrate tank (11). The concentrate is then pumped to the preheater (13) by the high-pressure material pump (12) to complete the preheating and temperature rise. After that, it enters the outer pipe section of the regenerator (14) to be further heated to the target temperature and then enters the high-temperature oxidation reactor (15) to react with the oxidant and be oxidized and degraded into harmless small molecule components. 5) After being treated by high-temperature oxidation, the effluent enters the inner pipe section of the regenerator (14) to release heat and cool down. Then, it enters the high-pressure side pipe section of the condenser (17) for further cooling to room temperature. After being depressurized to atmospheric pressure by the pressure reducer (18), it enters the gas-liquid-solid three-phase separator (19) and is separated into gas, liquid and solid three-phase products. The gas phase product enters the microalgae carbon fixation box (21) for the cultivation of algae slurry and external sales; the liquid phase product enters the greywater storage tank (24) for storage and is used to prepare new cutting fluid; the solid phase product metal scrap enters the metal scrap collection box (25) for storage and is used for metal scrap recycling. 6) Part of the cooling water in the circulating cooling water tank (22) enters the bottom of the cooling water jacket (16) to cool and protect the wall of the high-temperature oxidation reactor (15). The heat-absorbing cooling water turns into steam and enters the steam storage tank (23) from the top of the cooling water jacket (16) for storage. The other part enters the shell side of the condenser (17) to cool the water after the high-temperature reaction. The heat-absorbing cooling water turns into steam and enters the steam storage tank (23) from the top of the cooling water tank (22) for storage. The steam in the steam storage tank (23) is sold externally.

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