An environmentally friendly method of hydraulic fracturing

Abstract

This invention belongs to the field of environmental protection in hydraulic fracturing, specifically relating to an environmental protection method for hydraulic fracturing, comprising the following steps: S1, collection and homogenization; S2, preliminary filtration; S3, primary preheating; S4, secondary preheating; S5, associated gas pressure stabilization; S6, catalytic combustion; S7, high-pressure atomization; S8, spray evaporation and pollutant incineration; S9, waste heat recovery; S10, condensation; S11, product water collection; S12, tail gas recirculation treatment; S13, reuse. This environmental protection method for hydraulic fracturing, through a technical approach combining catalytic combustion and spray evaporation incineration, completely decomposes organic pollutants in the return fluid into carbon dioxide and water at high temperatures, achieving complete mineralization of the pollutants. Compared to the hazardous sludge produced by traditional coagulation and sedimentation methods, or the high-concentration brine produced by membrane separation methods, this method eliminates the problem of solid waste or concentrated liquid discharge. The full recirculation treatment of tail gas ensures that non-condensable gases are returned to the burner for complete decomposition, achieving near-zero emissions of air pollutants.

Description

Technical Field

[0001] This invention relates to the field of environmental protection technology for hydraulic fracturing, specifically to an environmental protection method for hydraulic fracturing. Background Technology

[0002] Hydraulic fracturing technology is widely used globally as a key method for exploiting unconventional oil and gas resources such as shale gas and tight oil. However, this technology generates large quantities of complex flowback fluids containing various chemical additives, high concentrations of salts, and suspended solids. Improper handling of these fluids can pose a serious threat to soil, groundwater, and surface water environments.

[0003] Currently, common methods for treating backflow liquid also have some limitations. Although coagulation and sedimentation can remove suspended solids, they produce a large amount of sludge, resulting in high subsequent treatment costs. Membrane separation technology can purify water, but it produces concentrated brine, and the membrane modules are prone to fouling, requiring high levels of operation and maintenance. Evaporation and crystallization technology can separate water and salt, but it consumes a lot of energy and has relatively high operating costs. In view of this, we propose an environmental protection method for hydraulic fracturing. Summary of the Invention

[0004] The main objective of this invention is to provide an environmental protection method for hydraulic fracturing that can solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention proposes an environmental protection method for hydraulic fracturing, comprising the following steps: S1. Collection and Homogenization: The liquid discharged after hydraulic fracturing is collected into a homogenization tank and homogenized by mechanical stirring. S2. Preliminary filtration: The homogenized return liquid is filtered through a basket filter with a precision of not less than 100 mesh. S3, First-stage preheating: The filtered return liquid is pumped into the first-stage heat exchanger to exchange heat with the low-temperature purified flue gas from step S12, raising its temperature to 60-70℃. S4, Secondary Preheating: The return liquid after primary preheating is pumped into the second-stage heat exchanger to exchange heat with the high-temperature mixed gas from step S9, raising its temperature to 90-95℃. S5. Associated gas pressure stabilization: The associated gas produced by the oil and gas well is introduced into the pressure stabilizing tank to stabilize its pressure within the range of 0.1-0.5MPa; S6. Catalytic Combustion: After the pressure-stabilized associated gas is mixed with air, it is introduced into a catalytic combustion reactor filled with a precious metal catalyst and catalytic combustion is carried out at a temperature of 450-600℃ to produce high-temperature flue gas of 600-700℃. S7. High-pressure atomization: The high-pressure plunger pump is used to pressurize the secondary preheated return liquid to 2-4 MPa, and then atomizes it into droplets with an average particle size of 20-80 micrometers through a pressure swirl atomizing nozzle. S8. Spray evaporation and pollutant incineration: The atomized droplets are sprayed into the high-temperature flue gas generated in step S6 to evaporate the moisture and oxidize and decompose the organic pollutants at the same time; the residence time of the gaseous mixture in the evaporation and incineration chamber is controlled to be no less than 2 seconds. S9. Waste heat recovery: The high-temperature mixed gas generated in step S8 is introduced into the second-stage heat exchanger as a heat source for step S4. S10, Condensation: The mixed gas after waste heat recovery is passed into the condenser to condense the water vapor in it into liquid water; S11. Product water collection: Collect high-quality reclaimed water obtained from condensation; S12, exhaust gas recirculation treatment: the non-condensable gas remaining after condensation in step S10 is transported back to the inlet of the catalytic combustion reactor in step S6 by an induced draft fan. S13. Reuse: Use the high-quality recycled water collected in step S11 to prepare new fracturing fluid.

[0006] Preferably, in step S2, the metal filter screen of the basket filter has a precision of 100 mesh, and its bottom is provided with an openable slag discharge port for periodically removing the trapped solid impurities. This effectively intercepts particulate matter that may cause blockage of subsequent equipment, and the bottom slag discharge port enables non-stop cleaning, ensuring the continuous and stable operation of the pretreatment process.

[0007] Preferably, the first-stage heat exchanger in step S3 is a stainless steel tubular heat exchanger; the second-stage heat exchanger in steps S4 and S9 is a titanium plate heat exchanger with a design pressure resistance of not less than 1.0 MPa. Stainless steel tubular heat exchangers have excellent pressure resistance and are suitable for initial heat exchange with flue gas; titanium plate heat exchangers, with their excellent corrosion resistance and high heat transfer efficiency, are very suitable for handling high-temperature and potentially corrosive process gases, and their clearly defined pressure resistance ensures the safety and reliability of the equipment under system pressure fluctuations.

[0008] Preferably, in step S5, the pressure stabilizing tank is equipped with a self-regulating pressure regulating valve to stabilize the associated gas pressure at 0.2 MPa, with a fluctuation range not exceeding ±0.02 MPa. Precise pressure control provides stable and uniform gas intake conditions for the downstream catalytic combustion reactor, which is a key prerequisite for ensuring stable combustion conditions and efficient and complete catalytic reaction.

[0009] Preferably, in step S6, the precious metal catalyst is a three-way catalyst with cordierite honeycomb ceramic as a support and palladium and platinum loaded in a weight ratio of 1:1. The pore density of the support is 400 pores / square inch. This specific catalyst formulation and structure can achieve complete combustion of associated gas at a relatively low temperature, while significantly inhibiting the generation of secondary pollutants such as nitrogen oxides, ensuring the production of high-temperature and clean heat source flue gas.

[0010] Preferably, in step S7, the outlet pressure of the high-pressure plunger pump is set to 3 MPa. Under this pressure, the pressure swirl atomizing nozzle generates a group of droplets with an average particle size of 50 micrometers. This parameter combination can achieve the best balance between energy consumption and atomization effect. The generated micrometer-sized droplets have a large specific surface area, which greatly enhances the heat and mass transfer process with high-temperature flue gas, creating conditions for instantaneous evaporation of moisture and rapid decomposition of pollutants.

[0011] Preferably, in step S8, the evaporation and incineration chamber is a vertical cylindrical structure with its inner wall lined with refractory material. The atomizing nozzle is tangentially arranged at the top, and the high-temperature flue gas is tangentially introduced at the bottom to form a swirling flow field, ensuring the residence time. The strong swirling flow field formed by tangential feeding not only effectively prolongs the residence time of the material in the reaction zone, ensuring the complete incineration of pollutants, but also avoids coking and corrosion problems caused by droplets directly impacting the container wall. The refractory material lining ensures the durability of the equipment under long-term high-temperature conditions.

[0012] Preferably, in step S11, the conductivity of the high-quality recycled water is less than 50 μS / cm, and its total organic carbon content is less than 10 ppm. These two key water quality indicators clearly define the produced water as high-purity water, which contains almost no soluble salts and organic pollutants, providing a fundamental guarantee that it can be directly used as a high-quality base liquid for the preparation of stable fracturing fluids.

[0013] Preferably, in step S12, the induced draft fan is a frequency-controlled corrosion-resistant fan, whose speed is automatically adjusted according to the back pressure at the condenser outlet to maintain a slightly negative pressure operating environment for the system. By maintaining a slightly negative pressure in the system through frequency conversion automatic control, it is possible to effectively prevent the leakage of any harmful gases, ensure operational safety, and at the same time ensure that the exhaust gas is completely drawn back and treated, thereby achieving closed-loop control of gaseous pollutants throughout the entire process.

[0014] Preferably, in step S13, when reusing the high-quality recycled water, the water ion composition is first analyzed, and then corrosion and scale inhibitors and clay stabilizers are added in a targeted manner for chemical conditioning to ensure its compatibility with formation fluids. This precise conditioning strategy based on water quality analysis can add the most necessary and appropriate amount of chemicals, ensuring the performance of fracturing fluid and its compatibility with the formation while minimizing the introduction of new chemicals, reflecting the concept of refined and green engineering management.

[0015] This invention provides an environmental protection method for hydraulic fracturing. It has the following beneficial effects: (1) This hydraulic fracturing environmental protection method, through a combination of catalytic combustion and spray evaporation incineration, completely decomposes organic pollutants in the return liquid into carbon dioxide and water at high temperatures, achieving complete mineralization of the pollutants. Compared with the hazardous sludge produced by traditional coagulation sedimentation methods or the high-concentration brine produced by membrane separation methods, this method has no solid waste or concentrated liquid discharge problems. At the same time, the full recirculation treatment of the exhaust gas ensures that non-condensable gases are sent back to the burner for complete decomposition, achieving near-zero emissions of air pollutants. This whole-process treatment method cuts off the pollutant transfer pathway at the source, achieving truly clean production.

[0016] (2) This hydraulic fracturing environmental protection method uses associated gas that needs to be processed in the oil and gas field as the main fuel of the system, realizing the energy utilization of waste resources. Through a two-stage preheating and waste heat recovery system, the heat energy generated in the process is efficiently used to preheat the feed, which greatly reduces the system's dependence on external energy. This design makes the fuel cost of the core processing unit approach zero, while the system energy consumption is significantly reduced. It breaks through the bottleneck of the traditional evaporation technology, which is limited by high energy consumption, and has significant economic and promotional value.

[0017] (3) The water produced by this hydraulic fracturing method meets high standards, with an electrical conductivity of <50 μS / cm and total organic carbon of <10 ppm. It can be directly used as the base water for fracturing fluid preparation, effectively avoiding fluctuations in additive dosage and performance uncertainty caused by unstable water quality. The entire system forms a complete closed-loop cycle of "flowback fluid - high-purity water - fracturing fluid", with no liquid discharge, minimizing the consumption of fresh water resources and providing an environmentally friendly and resource-saving sustainable solution for oil and gas field development in water-scarce areas. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the overall process flow of this invention is provided. Figure 2 This is a schematic diagram of some steps in the present invention; Figure 3 This is a schematic diagram of some steps in the present invention; Figure 4 This is a schematic diagram of some steps in the present invention; Figure 5 This is a schematic diagram of some steps in the present invention; Figure 6 This is a schematic diagram of some steps in the present invention; Figure 7 This is a schematic diagram of some steps in the present invention; Figure 8 This is a schematic diagram of some steps in the present invention; The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figure 1 - Figure 8 This invention proposes a specific implementation process for an environmental protection method for hydraulic fracturing: Step S1: Collection and Homogenization After hydraulic fracturing, the fluid returned from the wellhead is collected through a pipeline system into a 50m³ homogenizing tank. The tank is equipped with a mechanical agitator, with the agitation speed controlled at 30-60 rpm. Continuous agitation for 2-4 hours ensures that the fluid returned at different times, which exhibits significant quality fluctuations, is thoroughly mixed and reaches a stable state. In practical engineering applications, the volume of the homogenizing tank can be flexibly adjusted according to the amount of fluid returned on site, generally designed to be 1.2-1.5 times the daily processing capacity. The agitator's power configuration must ensure that the fluid inside the tank can form a sufficiently turbulent state to prevent solid particles from settling at the bottom of the tank.

[0022] Step S2: Preliminary Filtering The homogenized return liquid is then fed into a basket filter for filtration. This filter is made of 316 stainless steel with a 100-mesh screen and a quick-opening slag discharge valve at the bottom. In actual operation, solid impurities are removed through the slag discharge port every 200 m³ of liquid treated or when the inlet / outlet pressure difference reaches 0.1 MPa, effectively preventing clogging of downstream equipment and nozzles. To further improve the filtration effect, a coarse screen can be installed before the basket filter to intercept larger debris. The filter cleaning cycle should be adjusted according to the actual water quality. An automatic alarm will sound when the pressure difference reaches the set value, prompting for cleaning and maintenance.

[0023] Step S3: First-stage preheating The filtered drain liquid is pumped into the first-stage heat exchanger. This heat exchanger is a stainless steel tubular heat exchanger with a heat exchange area of ​​50 m². The drain liquid flows in the tube side and exchanges heat countercurrently with the low-temperature purified flue gas from the subsequent treatment unit in the shell side, raising the drain liquid temperature from ambient temperature to 60-70℃. The heat exchanger design should consider the fouling coefficient and allow sufficient heat exchange area margin. In actual operation, the ash accumulation on the outer wall of the heat exchange tubes should be checked regularly and purged and cleaned in a timely manner to maintain high heat transfer efficiency.

[0024] Step S4: Secondary preheating The preheated return liquid is pumped into the second-stage heat exchanger. This heat exchanger is a titanium plate heat exchanger, designed to withstand a pressure of 1.6 MPa. The return liquid exchanges heat with the high-temperature mixed gas from the evaporation and incineration process, further raising the return liquid temperature to 90-95°C, creating favorable conditions for subsequent evaporation. The plate spacing and corrugation of the plate heat exchanger are specially designed to ensure heat transfer efficiency while reducing the risk of blockage. The system is equipped with an automatic temperature control system that adjusts the fluid flow rate according to the outlet temperature to ensure that the preheating temperature remains stable within the set range.

[0025] Step S5: Stabilize associated gas pressure Associated gas produced from oil and gas wells is fed into a pressure stabilizing tank. The tank is equipped with a self-regulating pressure regulating valve to stabilize the associated gas pressure at 0.2 MPa, with fluctuations controlled within ±0.02 MPa. This stable pressure provides a reliable gas source for downstream catalytic combustion. A gas-liquid separator is installed before the pressure stabilizing tank to remove liquid droplets and solid particles carried in the associated gas. A safety relief device is also provided to automatically release pressure in case of overpressure, ensuring safe system operation. The calorific value of the associated gas is monitored online to provide a basis for subsequent combustion control.

[0026] Step S6: Catalytic Combustion The stabilized associated gas and preheated air are mixed in a stoichiometric ratio and then introduced into a catalytic combustion reactor. The reactor is filled with a precious metal catalyst, using cordierite honeycomb ceramic as a carrier with a pore density of 400 pores / square inch. The active components are palladium and platinum loaded in a 1:1 weight ratio. Under the action of the catalyst, the mixed gas undergoes flameless catalytic combustion within a temperature range of 450-600℃, producing high-temperature clean flue gas at 600-700℃. The catalytic combustion reactor employs a multi-layer catalyst arrangement to ensure complete and thorough reaction. Temperature monitoring points are installed inside the reactor to monitor the temperature distribution at each point in real time, preventing localized overheating that could affect catalyst lifespan. During the start-up phase, electric heating is used for preheating; once the temperature reaches the catalyst ignition temperature, the reactor switches to normal combustion mode.

[0027] Step S7: High-pressure atomization The preheated return liquid is pressurized to 3 MPa using a high-pressure plunger pump, and then atomized into droplets with an average particle size of 50 micrometers through a pressure swirl atomizing nozzle. The atomization angle is controlled between 60-80° to ensure uniform droplet distribution within the evaporation and incineration chamber. The high-pressure plunger pump is frequency-controlled, automatically adjusting the output flow rate according to the throughput. The atomizing nozzles are made of wear-resistant materials to extend their service life. The system is equipped with a pressure buffer device to eliminate pulsation generated by the plunger pump and ensure atomization stability.

[0028] Step S8: Spray Evaporation and Pollutant Incineration The atomized droplets are sprayed into the evaporation incineration chamber. This chamber is a vertical cylindrical structure with a 200mm thick refractory lining. Atomizing nozzles are tangentially positioned at the top, and high-temperature flue gas is tangentially introduced at the bottom, creating a strong swirling flow field. The residence time of the gaseous mixture within the chamber is controlled to 2-3 seconds to ensure complete oxidation and decomposition of organic pollutants into carbon dioxide and water. The design of the evaporation incineration chamber fully considers thermal expansion factors, incorporating expansion joints to compensate for thermal displacement. Multiple temperature monitoring points and observation ports are installed within the chamber for real-time monitoring of combustion and internal coking. The refractory material is a high-alumina castable, possessing excellent thermal stability and corrosion resistance.

[0029] Step S9: Waste Heat Recovery The mixed gas is introduced into the second-stage plate heat exchanger. The high-temperature gas temperature drops from 300-400℃ to 120-150℃, and the recovered heat is used for secondary preheating in step S4, significantly improving the system's thermal efficiency. The waste heat recovery system is equipped with a bypass regulating valve to flexibly adjust the heat exchange capacity according to process requirements. A temperature alarm is installed at the heat exchanger outlet to prevent acid corrosion caused by excessively low flue gas temperature. The heat exchange surfaces are cleaned regularly to maintain optimal heat transfer performance.

[0030] Step S10: Condensation The mixed gas, after waste heat recovery, is passed into a stainless steel shell-and-tube condenser. Circulating cooling water is used as the refrigerant to condense the water vapor in the mixed gas into liquid water. The condenser outlet gas temperature is reduced to below 40°C. The condenser is designed with a multi-pass structure to improve cooling efficiency. The cooling water system is equipped with a water treatment device to prevent scaling and corrosion. The condensate collection system features automatic level control to ensure a continuous and stable water output.

[0031] Step S11: Permeate collection High-quality recycled water is collected from condensation. Testing shows that the product water meets the requirements of conductivity less than 50 μS / cm, total organic carbon content less than 10 ppm, and turbidity less than 1 NTU, satisfying the standards for high-performance fracturing fluid preparation. The product water storage tank is made of food-grade corrosion-resistant materials and equipped with a nitrogen sealing system to prevent secondary pollution. Online water quality monitoring instruments monitor key indicators in real time to ensure stable compliance of the effluent quality. The product water system is equipped with multi-stage security filtration to further guarantee water purity.

[0032] Step S12: Exhaust gas recirculation treatment The remaining non-condensable gases after condensation are returned to the inlet of the catalytic combustion reactor via an induced draft fan. The induced draft fan is a frequency converter-controlled corrosion-resistant fan, with its speed automatically adjusted according to the condenser outlet back pressure to maintain the system operating pressure within a slightly negative pressure range of -100 to -500 Pa, ensuring zero emissions of gaseous pollutants. Pressure monitoring is installed before and after the induced draft fan for precise pressure control. A check valve is installed in the return pipeline to prevent gas backflow. The system is equipped with an emergency discharge device to ensure safe discharge in abnormal situations.

[0033] Step S13: Reuse When reusing the water, a comprehensive water quality analysis is first performed on the high-quality reclaimed water. Then, based on the analysis results, corrosion and scale inhibitors and clay stabilizers are added selectively. The dosage is precisely controlled according to the water's ionic composition, with the corrosion and scale inhibitor concentration ranging from 5 to 20 mg / L and the clay stabilizer concentration from 0.1% to 0.5%, ensuring good compatibility with formation fluids. The dosing system uses a precision metering pump to achieve precise control of the dosage. An online mixer is equipped to ensure thorough mixing of the chemicals and water. The mixing ratio of reclaimed water and additives is automatically adjusted based on real-time water quality analysis results to achieve optimal fracturing fluid preparation.

[0034] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An environmental protection method for hydraulic fracturing, comprising the following steps: S1. Collection and Homogenization: The liquid discharged after hydraulic fracturing is collected into a homogenization tank and homogenized by mechanical stirring. S2. Preliminary filtration: The homogenized return liquid is filtered through a basket filter with a precision of not less than 100 mesh. S3, First-stage preheating: The filtered return liquid is pumped into the first-stage heat exchanger to exchange heat with the low-temperature purified flue gas from step S12, raising its temperature to 60-70℃. S4, Secondary Preheating: The return liquid after primary preheating is pumped into the second-stage heat exchanger to exchange heat with the high-temperature mixed gas from step S9, raising its temperature to 90-95℃. S5. Associated gas pressure stabilization: The associated gas produced by the oil and gas well is introduced into the pressure stabilizing tank to stabilize its pressure within the range of 0.1-0.5 MPa; S6. Catalytic Combustion: After the pressure-stabilized associated gas is mixed with air, it is introduced into a catalytic combustion reactor filled with a precious metal catalyst and catalytic combustion is carried out at a temperature of 450-600℃ to produce high-temperature flue gas of 600-700℃. S7. High-pressure atomization: The high-pressure plunger pump is used to pressurize the secondary preheated return liquid to 2-4 MPa, and then atomizes it into droplets with an average particle size of 20-80 micrometers through a pressure swirl atomizing nozzle. S8. Spray evaporation and pollutant incineration: The atomized droplets are sprayed into the high-temperature flue gas generated in step S6 to evaporate the moisture and oxidize and decompose the organic pollutants at the same time; the residence time of the gaseous mixture in the evaporation and incineration chamber is controlled to be no less than 2 seconds. S9. Waste heat recovery: The high-temperature mixed gas generated in step S8 is introduced into the second-stage heat exchanger as a heat source for step S4. S10, Condensation: The mixed gas after waste heat recovery is passed into the condenser to condense the water vapor in it into liquid water; S11. Product water collection: Collect high-quality reclaimed water obtained from condensation; S12, exhaust gas recirculation treatment: the non-condensable gas remaining after condensation in step S10 is transported back to the inlet of the catalytic combustion reactor in step S6 by an induced draft fan. S13. Reuse: Use the high-quality recycled water collected in step S11 to prepare new fracturing fluid.

2. The environmental protection method for hydraulic fracturing according to claim 1, characterized in that: In step S2, the metal filter screen of the basket filter has a precision of 100 mesh, and its bottom is provided with a switchable slag discharge port for periodically removing trapped solid impurities.

3. The environmental protection method for hydraulic fracturing according to claim 1, characterized in that: The first-stage heat exchanger in step S3 is a stainless steel tubular heat exchanger; the second-stage heat exchanger in steps S4 and S9 is a titanium plate heat exchanger, designed to withstand a pressure of not less than 1.0 MPa.

4. The environmental protection method for hydraulic fracturing according to claim 1, characterized in that: In step S5, the pressure stabilizing tank is equipped with a self-regulating pressure regulating valve to stabilize the associated gas pressure at 0.2 MPa, with a fluctuation range not exceeding ±0.02 MPa.

5. The environmental protection method for hydraulic fracturing according to claim 1, characterized in that: In step S6, the noble metal catalyst is a three-way catalyst with cordierite honeycomb ceramic as a support and palladium and platinum loaded in a weight ratio of 1:1, and the support pore density is 400 pores / square inch.

6. The environmental protection method for hydraulic fracturing according to claim 1, characterized in that: In step S7, the outlet pressure of the high-pressure plunger pump is set to 3 MPa, and the pressure swirl atomizing nozzle generates a group of droplets with an average particle size of 50 micrometers under this pressure.

7. The environmental protection method for hydraulic fracturing according to claim 1, characterized in that: In step S8, the evaporation incineration chamber is a vertical cylindrical structure with its inner wall lined with refractory material. The atomizing nozzle is tangentially arranged at the top, and the high-temperature flue gas is tangentially introduced at the bottom to form a swirling flow field and ensure the residence time.

8. The environmental protection method for hydraulic fracturing according to claim 1, characterized in that: In step S11, the high-quality recycled water has a conductivity of less than 50 μS / cm and a total organic carbon content of less than 10 ppm.

9. The environmental protection method for hydraulic fracturing according to claim 1, characterized in that: In step S12, the induced draft fan is a frequency-controlled corrosion-resistant fan, and its speed is automatically adjusted according to the back pressure at the condenser outlet to maintain a slightly negative pressure operating environment for the system.

10. The environmental protection method for hydraulic fracturing according to claim 1, characterized in that: In step S13, when reusing the water, the water quality ionic composition of the high-quality recycled water is first analyzed, and then corrosion and scale inhibitors and clay stabilizers are added in a targeted manner for chemical conditioning to ensure its compatibility with the formation fluid.

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