Coupling catalytic oxidation in-situ remediation device and method for petroleum-contaminated soil

Abstract

The invention discloses a coupling catalytic oxidation in-situ remediation device and method for petroleum-contaminated soil. The device comprises a chemical mixer, and the chemical mixer is connected with a liquid conveying pipe through a feeding pump; the ozone generator is connected with the gas conveying pipe through the gas pump; the gas conveying pipe is arranged in the liquid conveying pipe and is coaxial with the liquid conveying pipe; the liquid conveying pipe and the gas conveying pipe are connected with the injector, the injector sprays chemicals and ozone to the oil-contaminated soil, and the gas absorption film is flatly laid on the oil-contaminated soil; petroleum hydrocarbon components in the petroleum-contaminated soil are removed in situ in an efficient and environment-friendly mode, and safe disposal of the petroleum-contaminated soil is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of in-situ remediation of petroleum-contaminated soil, and in particular to a coupled catalytic oxidation in-situ remediation device and method for petroleum-contaminated soil. Background Art

[0002] As an important strategic energy source, with the rapid development of society, people's demand for petroleum products has increased dramatically, and the resulting oil pollution problem has become increasingly prominent. These pollutants will eventually enter the soil through various channels, causing oil pollution in the soil. Due to its special physical and chemical properties, oil pollutants will cause lasting and irreparable damage to the soil, water and atmospheric environment.

[0003] There are many different technologies for remediation of oil-contaminated soil. Due to the complexity of oil components, the physical and chemical properties of different types of oil-contaminated soil vary greatly, and the applicable remediation methods are also different. For oil-contaminated soil with heavy oil components such as colloids and aromatic hydrocarbons as the main pollutants, the existing physical remediation methods have low applicability and are greatly restricted by soil properties; heavy oil components are highly toxic to organisms, and biological remediation is difficult; chemical remediation efficiency is low and simple chemical remediation methods are difficult to efficiently remove oil and achieve harmlessness of oil-contaminated soil (Li Yuanning et al., Applied Chemical Engineering, 2022, 51(6): 1736-1739).

[0004] In order to ensure that the physical and chemical properties of petroleum-contaminated soil meet national standards and achieve its harmlessness, a more efficient and environmentally friendly in-situ remediation technology is urgently needed to destroy and remove heavy components in petroleum-contaminated soil. Summary of the invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a coupled catalytic oxidation in-situ remediation device and method for petroleum-contaminated soil, which can efficiently and environmentally friendly remove petroleum hydrocarbon components in petroleum-contaminated soil in situ and achieve safe disposal of petroleum-contaminated soil.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A coupled catalytic oxidation in-situ remediation device for petroleum contaminated soil comprises a reagent mixer 1, which is connected to a liquid delivery pipe 6 via a feed pump 2; an ozone generator 3 is connected to a gas delivery pipe 5 via an air pump 4; the gas delivery pipe 5 is placed in the liquid delivery pipe 6 and is coaxially arranged; the liquid delivery pipe 6, the gas delivery pipe 5 and an injector 7 are connected, the injector 7 sprays reagents and ozone on the petroleum contaminated soil, and a gas absorption membrane 8 is laid flat on the petroleum contaminated soil.

[0008] The pharmaceutical mixer 1 comprises a tank body 11, a first feed port 12 and a second feed port 13 provided at the top of the tank body 11 are respectively a catalyst inlet and a potassium persulfate solution inlet, a stirrer 14 is provided inside the tank body 11, a first discharge port 15 provided at the bottom of the tank body 11 is connected to the discharge port of the feed pump 2, and the stirring speed of the stirrer 14 is 400-600 rpm.

[0009] The ozone generator 3 comprises a gas generating chamber 32, wherein the air source inlet 31 provided in the gas generating chamber 32 is an air inlet, and the second discharge port 33 provided in the gas generating chamber 32 is connected to the inlet of the air pump 4, and the gas generating chamber 32 prepares ozone gas by using air.

[0010] The gas delivery pipe 5 comprises a first tube body 52, one end of which is a gas feed port 51, which is connected to the outlet of the air pump 4; the other end of the first tube body 52 is closed and has a spiral structure cast on the outside, which is connected to the liquid delivery pipe 6 through the spiral structure; the first tube body 52 is provided with a plurality of gas outlets 53;

[0011] The liquid delivery pipe 6 includes a second pipe body 62, one end of which is a liquid feed port 61, which is connected to the discharge port of the feed pump 2; the other end of the second pipe body 62 is closed and has a spiral structure cast inside, which is connected to the gas delivery pipe 5 through the spiral structure; the second pipe body 62 is provided with a plurality of liquid discharge ports 63;

[0012] The gas outlet 53 and the liquid outlet 63 are coaxially arranged; the center distance between the gas outlet 53 and the liquid outlet 63 is 0.5-1.5m, and the diameter of the first tube body 52 is 40-60mm.

[0013] The injector 7 comprises an injection tube outer tube 72 and an injection tube inner tube 75, wherein the injection tube inner tube 75 is placed inside the injection tube outer tube 72 and is coaxially arranged; one end of the injection tube inner tube 75 is a gas inlet 74, which is connected to the gas outlet 53 through a quick connector, and the other end of the injection tube inner tube 75 is a gas injection hole 76, and the gas injection hole 76 discharges ozone gas; one end of the injection tube outer tube 72 is a liquid inlet 71, which is connected to the liquid outlet 63 through a quick connector, and a plurality of liquid injection holes 73 are arranged on the injection tube outer tube 72, and the liquid injection holes 73 discharge a mixed solution of a catalyst and potassium sulfate.

[0014] The outer tube 72 of the injection tube has a diameter of 30 to 50 mm, a length of 0.8 to 1.2 m, an opening at the bottom and a spiral structure inside, and is connected to the inner tube 75 of the injection tube through the spiral structure; the inner tube 75 of the injection tube has a diameter of 10 to 20 mm, a spiral structure on the outside of the bottom, and is connected to the outer tube 72 of the injection tube through the spiral structure; the diameter of the liquid injection hole 73 needs to be greater than 0.6 mm, and the hole should be evenly opened.

[0015] The ozone generator 3, gas delivery pipe 5, liquid delivery pipe 6 and injector 7 are made of ferrochrome alloy (stainless steel) containing 25% Cr.

[0016] The gas absorption membrane 8 is a carbon nanofiber film whose surface coating is titanium dioxide.

[0017] A method for using a coupled catalytic oxidation in-situ remediation device for petroleum-contaminated soil comprises the following steps:

[0018] The first step is to divide the oil contaminated site into modules. According to the geology, topography and area of ​​the oil contaminated site, the site is divided into several regular restoration units. First, an injection well with a depth of 0.8 to 1.2 m and a diameter of 40 to 50 mm is vertically drilled in the first restoration unit, and the interval between each injection well is 0.5 to 1.5 m. After the injection well is drilled, an injection pipe outer pipe 72 with the same depth as the injection well is installed in each injection well, and then the injection pipe inner pipe 75 is extended into the injection pipe outer pipe 72, and the injection pipe inner pipe 75 and the injection pipe outer pipe 72 are connected by a spiral structure.

[0019] The second step is to connect the gas delivery pipe 5 to the inside of the liquid input pipe 6, and then connect the gas outlet 53 to the inner tube 75 of the injection pipe through a quick connector, and at the same time connect the liquid outlet 63 to the outer tube 72 of the injection pipe; connect the gas feed port 51 to the outlet of the air pump 4, and then connect the inlet of the air pump 4 to the second outlet 33 of the ozone generator 3; then connect the liquid feed port 61 to the outlet of the feed pump 2, and connect the feed port of the feed pump 2 to the first outlet 15 of the pharmaceutical mixer 1; check the air tightness of each pipeline, and lay the gas absorption membrane 8 flat on the repair unit where the pipeline has been laid;

[0020] In the third step, the catalyst is fed into the reagent mixer 1 through the first feed port 12, and the potassium persulfate solution with a mass concentration of 2-4% is fed into the reagent mixer 1 through the second feed port 13, and the stirrer 14 is started to stir and mix. The mixed reagent is discharged from the first discharge port 15 of the reagent mixer 1, and then fed into the liquid feed port 61 of the liquid delivery pipe 6 through the feed pump 2; at the same time, the ozone generator 3 is turned on, and air enters the ozone generating chamber 32 from the air source inlet 31 of the ozone generator 3 to prepare an ozone generating chamber 32 with a concentration of 2-3 mg / L ozone, ozone is discharged from the second discharge port 33 of the ozone generator 3, and is sent to the gas feed port 51 of the gas delivery pipe 5 through the air pump 4; the ozone gas in the gas delivery pipe 5 is sent to the injection pipe inner tube 75 of the injector 7, and then sent to the petroleum contaminated soil from the gas injection hole 76, and at the same time, the mixed agent is sent from the liquid delivery pipe 6 to the injection pipe outer tube 72 of the injector 7, and then evenly sent to the petroleum contaminated soil from the liquid injection hole 73 of the injection pipe outer tube 72, and the oxidation treatment is carried out for 2.5-3.5 hours;

[0021] The fourth step is to perform the first step on the second repair unit while repairing the first repair unit, drill an injection well and install the injector 7. After the first repair unit is repaired, remove the gas absorption membrane 8 and all pipelines laid on the ground, and complete the installation and air tightness inspection of all pipelines according to the second step, and lay the gas absorption membrane 8 flat on top of the repair unit with the laid pipelines; then repair the second repair unit according to the third step, and so on, to complete the repair of the entire oil contaminated site.

[0022] The catalyst is a carbon-supported iron catalyst with a particle size of 0.15-0.25 mm, and the mass ratio of the potassium persulfate solution to the catalyst is 100-120:1.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention is the first to use a coupled oxidation method of carbon-supported iron catalyzed persulfate and ozone in the in-situ remediation of petroleum-contaminated soil. The coupling mechanism of the two oxidants can increase the concentration and stability of free radicals to efficiently degrade petroleum pollutants in the soil.

[0025] 2. The oxygen produced by ozone decomposition can also increase the oxygen content in the soil, which is beneficial to plant growth. At the same time, the oxidation product of potassium persulfate is potassium sulfate, which can be used as potassium fertilizer to increase soil fertility. In addition, the sulfate ions produced after repair can increase soil acidity and adjust the soil pH for alkaline soils.

[0026] 3. The gas delivery pipe 5 and the liquid delivery pipe 6 of the present invention are arranged in sleeves and are respectively connected to the injection pipe inner pipe 75 and the injection pipe outer pipe 72 of the injector 7 through quick connectors, which is convenient for construction. At the same time, the mixed agent is discharged from the liquid injection hole 73 of the injection pipe outer pipe 72, and the ozone is discharged from the gas injection hole 76 of the injection pipe inner pipe 75, which increases the coupling action time and utilization efficiency of the two oxidants and effectively reduces the diffusion pollution of the two oxidants.

[0027] 4. The present invention adopts an advanced oxidation method of iron-carbon activated potassium persulfate coupled with ozone, which can not only oxidize and remove petroleum hydrocarbons and aromatic compounds in polluted soil, especially the removal of heavy petroleum hydrocarbon components, but also achieve the stabilization / immobilization of heavy metals therein; in addition, activated carbon itself is a good soil conditioner, which is beneficial to improving soil structure.

[0028] 5. The in-situ petroleum-contaminated soil remediation device of the present invention minimizes the disturbance and damage to the soil layer, reduces the impact on soil functions, and reduces the remediation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1Schematic diagram of a device according to an embodiment of the present invention.

[0030] Figure 2 It is a schematic diagram of the gas delivery pipe 5, the interior of the liquid input pipe 6 and the injector 7 of the device according to an embodiment of the present invention.

[0031] Figure 3 This is a schematic diagram of the layout of the petroleum-contaminated soil injection well in Example 1 of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0033] Example 1 takes the treatment of an oil-contaminated site with a soil oil pollution concentration of 5000 mg / kg, a pollution depth of 50 cm, a length of 100 m, and a width of 25 m as an example.

[0034] Reference Figure 1 , Figure 2 A coupled catalytic oxidation in-situ remediation device for petroleum contaminated soil includes a reagent mixer 1, which is connected to a liquid delivery pipe 6 via a feed pump 2; an ozone generator 3 is connected to a gas delivery pipe 5 via an air pump 4; the gas delivery pipe 5 is placed in the liquid delivery pipe 6 and is coaxially arranged; the liquid delivery pipe 6, the gas delivery pipe 5 and an injector 7 are connected, the injector 7 sprays reagents and ozone on the petroleum contaminated soil, and a gas absorption membrane 8 is laid flat on the petroleum contaminated soil.

[0035] Reference Figure 1 The pharmaceutical mixer 1 comprises a tank body 11, a first feed port 12 and a second feed port 13 provided on the top of the tank body 11 are respectively a catalyst inlet and a potassium persulfate solution inlet, a stirrer 14 is provided inside the tank body 11, and the stirrer 14 is placed in the middle of the tank body 11, a first discharge port 15 provided at the bottom of the tank body 11 is connected to the discharge port of the feed pump 2, and the stirring speed of the stirrer 14 is 500 rpm, and its purpose is to fully mix the catalyst and the potassium sulfate solution.

[0036] Reference Figure 1 The ozone generator 3 includes a gas generating chamber 32, the gas generating chamber 32 is provided with an air source inlet 31 as an air inlet, the gas generating chamber 32 is provided with a second discharge port 33 connected to the inlet of the air pump 4, and the gas generating chamber 32 uses air to prepare ozone gas.

[0037] Reference Figure 2 The gas delivery pipe 5 includes a first tube body 52, one end of which is a gas feed port 51, and the gas feed port 51 is connected to the outlet of the air pump 4; the other end of the first tube body 52 is closed and has a spiral structure cast on the outside, and is connected to the liquid delivery pipe 6 through the spiral structure; a plurality of gas outlets 53 are provided on the first tube body 52.

[0038] Reference Figure 2 The liquid delivery pipe 6 includes a second tube body 62, one end of which is a liquid feed port 61, and the liquid feed port 61 is connected to the discharge port of the feed pump 2; the other end of the second tube body 62 is closed and has a spiral structure cast inside, which is connected to the gas delivery pipe 5 through the spiral structure; a plurality of liquid discharge ports 63 are provided on the second tube body 62.

[0039] The gas outlet 53 and the liquid outlet 63 are coaxially arranged; the center distance between the gas outlet 53 and the liquid outlet 63 is 1m, and the diameter of the first tube body 52 is 50mm.

[0040] Reference Figure 2 The injector 7 comprises an injection tube outer tube 72 and an injection tube inner tube 75, wherein the injection tube inner tube 75 is placed inside the injection tube outer tube 72 and arranged coaxially; one end of the injection tube inner tube 75 is a gas inlet 74, which is connected to the gas outlet 53 through a quick connector, and the other end of the injection tube inner tube 75 is a gas injection hole 76, and the gas injection hole 76 discharges ozone gas; one end of the injection tube outer tube 72 is a liquid inlet 71, which is connected to the liquid outlet 63 through a quick connector, and a plurality of liquid injection holes 73 are arranged on the injection tube outer tube 72, and the liquid injection holes 73 discharge a mixed solution of catalyst and potassium sulfate.

[0041] The outer tube 72 of the injection tube has a diameter of 40 mm, a length of 1 m, an open bottom and a spiral structure inside, which is connected to the inner tube 75 of the injection tube via the spiral structure; the inner tube 75 of the injection tube has a diameter of 15 mm, a spiral structure on the outside of the bottom, and is connected to the outer tube 72 of the injection tube via the spiral structure.

[0042] The diameter of the liquid injection hole 73 should be larger than 0.6 mm and the holes should be opened evenly.

[0043] The ozone generator 3, gas delivery pipe 5, liquid delivery pipe 6 and injector 7 are made of ferrochrome alloy (stainless steel) containing 25% Cr.

[0044] The gas absorption membrane 8 is a carbon nanofiber film whose surface coating is titanium dioxide.

[0045] A method for using a coupled catalytic oxidation in-situ remediation device for petroleum-contaminated soil comprises the following steps:

[0046] The first step is to refer to Figure 3, the oil contaminated site is divided into 4 25×25m restoration units, firstly, an injection well with a depth of 1m and a diameter of 45mm is vertically drilled in the first restoration unit, and each injection well is spaced 1m apart; after the injection well is drilled, an injection pipe outer tube 72 with the same depth as the injection well is installed into each injection well, and then the injection pipe inner tube 75 is extended into the injection pipe outer tube 72, and the injection pipe inner tube 75 and the injection pipe outer tube 72 are fixed by the spiral structure at the bottom of the injection pipe inner tube 75 and the injection pipe outer tube 72;

[0047] The second step is to place the gas delivery pipe 5 inside the liquid input pipe 6, clamp the spiral structure at the end of the first tube body 52 of the gas delivery pipe 5 and the second tube body 62 of the liquid input pipe 6 to fix the gas delivery pipe 5 and the liquid input pipe 6, then connect the gas outlet 53 of the gas delivery pipe 5 to the injection pipe inner pipe 75 of the injector 7 through a quick connector, and at the same time connect the liquid outlet 63 of the liquid delivery pipe 6 to the injection pipe outer pipe 72 of the injector 7; connect the gas feed port 51 of the gas delivery pipe 5 to the outlet of the air pump 4 through a pipeline, and then connect the inlet of the air pump 4 to the second discharge port 33 of the ozone generator 3; then connect the liquid feed port 61 of the liquid delivery pipe 6 to the outlet of the feed pump 2 through a pipeline, and connect the feed port of the feed pump 2 to the first discharge port 15 of the pharmaceutical mixer 1; after all pipelines are connected, check the air tightness of each pipeline, and lay a 27×27m gas absorption membrane 8 flat on the top of the repair unit where the pipeline has been laid;

[0048] In the third step, a carbon-supported iron catalyst with a particle size of 0.2 mm and a carbon loading rate of 10% is fed into the first feed port 12 of the reagent mixer 1 at a feed rate of 0.36 t / h, and a potassium persulfate solution with a mass concentration of 3% is fed into the second feed port 13 of the reagent mixer 1 at a flow rate of 39.96 t / h, and the stirrer 14 is started to stir and mix at a stirring speed of 500 rpm. The mixed reagent is discharged from the first discharge port 15 of the reagent mixer 1, and then fed into the liquid feed port 61 of the liquid delivery pipe 6 through the feed pump 2; at the same time, the ozone generator 3 is turned on, and air enters the ozone generating chamber 32 from the air source inlet 31 of the ozone generator 3 to produce ozone with a concentration of 2.5 mg / L, and then the ozone is discharged from the second discharge port 33 of the ozone generator 3 at a flow rate of 840 m 3 / h flow rate discharge, and then sent to the gas feed port 51 of the gas delivery pipe 5 through the air pump 4; the ozone gas in the gas delivery pipe 5 is sent to the injection pipe inner tube 75 of the injector 7, and then sent to the petroleum contaminated soil from the gas injection hole 76, and at the same time, the mixed agent is sent from the liquid delivery pipe 6 to the injection pipe outer tube 72 of the injector 7, and then evenly sent to the petroleum contaminated soil from the liquid injection hole 73 of the injection pipe outer tube 72, and the oxidation remediation treatment is carried out for 3 hours;

[0049] The fourth step is to perform the first step on the second repair unit while repairing the first repair unit, drill an injection well and install the injector 7. After the first repair unit is repaired, remove the gas absorption membrane 8 and all pipelines laid on the ground, and complete the installation and air tightness inspection of all pipelines according to the second step, and lay the gas absorption membrane 8 flat on the top of the repair unit with the laid pipeline; then repair the second repair unit according to the third step, and repair the four repair units in turn to complete the repair of the entire oil contaminated site.

[0050] According to this embodiment, the total petroleum hydrocarbon concentration in the petroleum contaminated soil after oxidation treatment for 3 hours can be removed by more than 50%, thereby achieving efficient and harmless treatment of the petroleum contaminated soil. The total petroleum hydrocarbon residue in the soil after treatment is lower than the total petroleum hydrocarbon (TPH) concentration standard for Class II construction land in China (4500 mg / kg soil) (GB3660-2018).

[0051] Example 2: The oil contaminated site is the same as Example 1, and the difference between the repair device and Example 1 is that the stirring speed of the stirrer 14 is 400rpm, the center distance between the gas outlet 53 and the liquid outlet 63 is 0.5m, and the diameter of the first pipe 52 is 40mm. The difference between the repair method and Example 1 is that in the first step, the first repair unit vertically drills an injection well with a depth of 0.8m and a diameter of 40mm, and each injection well is spaced 0.5m apart; in the third step, the mass concentration of the potassium persulfate solution is 2%, the ozone production concentration is 2mg / L, and the oxidation treatment is 2.5h; the catalyst particle size is 0.15mm; the mass ratio of the potassium persulfate solution to the catalyst is 100:1.

[0052] The effect of this embodiment on petroleum contaminated soil is similar to that of embodiment 1.

[0053] Example 3: The oil contaminated site is the same as Example 1, and the difference between the repair device and Example 1 is that the stirring speed of the stirrer 14 is 600rpm, the center distance between the gas outlet 53 and the liquid outlet 63 is 1.5m, and the diameter of the first pipe 52 is 60mm. The difference between the repair method and Example 1 is that in the first step, the first repair unit vertically drills an injection well with a depth of 1.2m and a diameter of 50mm, and each injection well is spaced 1.5m apart; in the third step, the mass concentration of the potassium persulfate solution is 4%, the ozone production concentration is 3mg / L, and the oxidation treatment is 3.5h; the catalyst particle size is 0.25mm; the mass ratio of the potassium persulfate solution to the catalyst is 120:1.

[0054] The effect of this embodiment on petroleum contaminated soil is similar to that of embodiment 1.

[0055] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field shall fall within the protection scope of the claims of the present invention.

Claims

1. A coupled catalytic oxidation in-situ remediation device for petroleum-contaminated soil, comprising a reagent mixer (1), characterized in that: The reagent mixer (1) is connected to a liquid delivery pipe (6) via a feed pump (2); the ozone generator (3) is connected to a gas delivery pipe (5) via an air pump (4); the gas delivery pipe (5) is placed inside the liquid delivery pipe (6) and is coaxially arranged; the liquid delivery pipe (6), the gas delivery pipe (5) and an injector (7) are connected, the injector (7) sprays the reagent and ozone onto the petroleum contaminated soil, and the gas absorption film (8) is spread on the petroleum contaminated soil.

2. The device according to claim 1, characterized in that The pharmaceutical mixer (1) comprises a tank body (11), a first feed port (12) and a second feed port (13) provided on the top of the tank body (11) are respectively a catalyst inlet and a potassium persulfate solution inlet, a stirrer (14) is provided inside the tank body (11), a first discharge port (15) provided on the bottom of the tank body (11) is connected to the discharge port of a feed pump (2), and the stirring speed of the stirrer (14) is 400-600 rpm.

3. The device according to claim 1, characterized in that The ozone generator (3) comprises a gas generating chamber (32), the air source inlet (31) provided in the gas generating chamber (32) is an air inlet, the second discharge port (33) provided in the gas generating chamber (32) is connected to the inlet of the air pump (4), and the gas generating chamber (32) uses air to prepare ozone gas.

4. The device according to claim 1, characterized in that The gas delivery pipe (5) comprises a first pipe body (52), one end of the first pipe body (52) is a gas feed port (51), and the gas feed port (51) is connected to the outlet of the air pump (4); the other end of the first pipe body (52) is closed and has a spiral structure cast on the outside, and is connected to the liquid delivery pipe (6) through the spiral structure; the first pipe body (52) is provided with a plurality of gas outlets (53); The liquid delivery pipe (6) comprises a second pipe body (62), one end of the second pipe body (62) is a liquid feed port (61), and the liquid feed port (61) is connected to the discharge port of the feed pump (2); the other end of the second pipe body (62) is closed and has a spiral structure cast inside, and is connected to the gas delivery pipe (5) through the spiral structure; the second pipe body (62) is provided with a plurality of liquid discharge ports (63); The gas outlet (53) and the liquid outlet (63) are coaxially arranged; the center distance between the gas outlet (53) and the liquid outlet (63) is 0.5 to 1.5 m, and the diameter of the first tube body (52) is 40 to 60 mm.

5. The device according to claim 4, characterized in that The injector (7) comprises an injection tube outer tube (72) and an injection tube inner tube (75), wherein the injection tube inner tube (75) is placed inside the injection tube outer tube (72) and is coaxially arranged; one end of the injection tube inner tube (75) is a gas inlet (74), which is connected to a gas outlet (53) via a quick connector, and the other end of the injection tube inner tube (75) is a gas injection hole (76), and ozone gas is discharged from the gas injection hole (76); one end of the injection tube outer tube (72) is a liquid inlet (71), which is connected to a liquid outlet (63) via a quick connector, and a plurality of liquid injection holes (73) are arranged on the injection tube outer tube (72), and a mixed solution of a catalyst and potassium sulfate is discharged from the liquid injection holes (73).

6. The device according to claim 5, characterized in that The outer tube (72) of the injection tube has a diameter of 30 to 50 mm, a length of 0.8 to 1.2 m, an opening at the bottom and a spiral structure inside, and is connected to the inner tube (75) of the injection tube via the spiral structure; the inner tube (75) of the injection tube has a diameter of 10 to 20 mm, a spiral structure on the outside of the bottom, and is connected to the outer tube (72) of the injection tube via the spiral structure; the diameter of the liquid injection hole (73) must be greater than 0.6 mm, and the hole must be evenly opened.

7. The device according to claim 1, characterized in that The ozone generator (3), gas delivery pipe (5), liquid delivery pipe (6) and injector (7) are made of chromium-iron alloy containing 25% Cr; the gas absorption membrane (8) is made of a carbon nanofiber film with a surface coating of titanium dioxide.

8. A method for using the coupled catalytic oxidation in-situ remediation device for petroleum-contaminated soil according to any one of claims 1 to 7, characterized in that: The following steps are involved: The first step is to divide the oil contaminated site into modules, and divide the site into a number of regular restoration units according to the geology, topography and area of ​​the oil contaminated site. First, an injection well with a depth of 0.8 to 1.2 m and a diameter of 40 to 50 mm is vertically drilled in the first restoration unit, and the interval between each injection well is 0.5 to 1.5 m. After the injection wells are drilled, an injection pipe outer tube (72) with the same depth as the injection well is installed in each injection well, and then the injection pipe inner tube (75) is extended into the injection pipe outer tube (72), and the injection pipe inner tube (75) and the injection pipe outer tube (72) are connected by a spiral structure. The second step is to connect the gas delivery pipe (5) to the inside of the liquid input pipe (6), and then connect the gas outlet (53) to the inner pipe (75) of the injection pipe through a quick connector, and at the same time connect the liquid outlet (63) to the outer pipe (72) of the injection pipe; connect the gas feed port (51) to the outlet of the air pump (4), and then connect the inlet of the air pump (4) to the outlet (33) of the ozone generator (3); then connect the liquid feed port (61) to the outlet of the feed pump (2), and connect the feed port of the feed pump (2) to the outlet (15) of the reagent mixer (1); check the air tightness of each pipeline, and lay the gas absorption membrane (8) flat on the repair unit where the pipeline has been laid; In the third step, the catalyst is introduced into the reagent mixer (1) through the first feed port (12), and at the same time, a potassium persulfate solution with a mass concentration of 2 to 4% is introduced into the reagent mixer (1) through the second feed port (13), and the stirrer (14) is started to stir and mix. The mixed reagent is discharged from the discharge port (15) of the reagent mixer (1) and then fed into the liquid feed port (61) of the liquid delivery pipe (6) through the feed pump (2); at the same time, the ozone generator (3) is turned on, and air enters the ozone generating chamber (32) from the air source inlet (31) of the ozone generator (3) to produce an ozone with a concentration of 2-3 mg / L of ozone is discharged from the discharge port (33) of the ozone generator (3) and fed into the gas feed port (51) of the gas delivery pipe (5) through the air pump (4); the ozone gas of the gas delivery pipe (5) is fed into the inner tube (75) of the injection pipe of the injector (7), and then fed into the petroleum-contaminated soil from the gas injection hole (76); at the same time, the mixed agent is fed from the liquid delivery pipe (6) into the outer tube (72) of the injection pipe of the injector (7), and then evenly fed into the petroleum-contaminated soil from the liquid injection hole (73) of the outer tube (72) of the injection pipe, and the oxidation treatment is carried out for 2.5-3.5 hours; The fourth step is to perform the first step on the second repair unit while repairing the first repair unit, drill an injection well and install an injector (7). After the first repair unit is repaired, remove the gas absorption membrane (8) and all pipelines laid on the ground, and complete the installation and air tightness inspection of all pipelines according to the second step, and lay the gas absorption membrane (8) flat on the top of the repair unit with the laid pipeline; then repair the second repair unit according to the third step, and so on, to complete the repair of the entire oil contaminated site.

9. The method according to claim 8, characterized in that: The catalyst is a carbon-supported iron catalyst with a particle size of 0.15-0.25 mm, and the mass ratio of the potassium persulfate solution to the catalyst is 100-120:1.

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