A coking wastewater ozone catalytic oxidation deep treatment device and its operation mode

Abstract

A coking wastewater ozone catalytic oxidation deep treatment device and operating method belongs to the field of coking wastewater treatment technology. The device includes a pure oxygen storage tank, an ozone generator, an ozone compressor, an ozone catalytic oxidation tank B, and an ozone catalytic oxidation tank A, which are connected in sequence. High-concentration ozone is used in the ozone catalytic oxidation tank B to degrade low-concentration organic pollutants, achieving complete degradation of the organic pollutants. At the same time, low-concentration ozone is used in the ozone catalytic oxidation tank A to degrade high-concentration organic pollutants, achieving efficient utilization of ozone. The cyclic process of using high-concentration ozone to degrade low-concentration organic pollutants and low-concentration ozone to degrade high-concentration organic pollutants solves the problems of large ozone tail gas emissions, low ozone utilization rate, and difficult degradation of organic pollutants in coking wastewater, improves the effective utilization rate of ozone, and avoids the problem of ozone tail gas treatment, reducing the cost of sewage treatment and improving economic practicality.

Description

Technical Field

[0001] The present invention relates to the technical field of coking wastewater treatment, and in particular to a device and an operating method for deeply treating coking wastewater by pressurized enhanced ozone catalytic oxidation. Background Art

[0002] Coking wastewater generally refers to the collective term for wastewater generated in various stages of the coking process. Its main sources include condensate formed in the primary cooling stage during raw coal pyrolysis, washing wastewater generated during coal gas processing and purification, and wastewater generated during the recycling of chemical products such as tar and crude benzene. As a typical industrial high-concentration organic wastewater, coking wastewater is widely present with dissolved organic matter such as phenols, benzene, heterocyclic compounds, and polycyclic compounds. Among these substances, phenolic compounds are the most abundant, accounting for over half of the total organic matter content. These compounds include phenol, o-cresol, p-cresol, and xylenol. Benzene and its derivatives include benzene, toluene, xylene, naphthalene, anthracene, phenanthrene, and benzopyrene. Heterocyclic compounds include quinoline, pyridine, hydrazine, carbazole, furan, and thiophene. Inorganic compounds primarily include ammonia nitrogen, sulfate, chloride, carbonate (hydrogen), thiocyanate, cyanide-containing compounds (cyanide and ferrocyanide), and sulfide ions. Due to its complex composition, coking wastewater is highly toxic and difficult to degrade. If it is not handled properly, it will cause serious damage to the entire ecological environment.

[0003] Currently, biological methods are the most widely used in coking wastewater treatment. However, due to their high toxicity and low biodegradability, the COD and color of the effluent from these methods often fail to meet expected emission standards. Therefore, the search for advanced treatment methods is an urgent issue. Catalytic ozonation is widely known as a green and efficient water treatment technology. By promoting ozone decomposition to produce highly oxidizing, non-selective hydroxyl radicals, it can effectively remove recalcitrant and biotoxic organic compounds, such as phenols, polycyclic aromatic hydrocarbons, and nitrogen-containing heterocyclic compounds, from coking wastewater. Furthermore, this technology offers rapid reaction rates, virtually no residual chemicals, and minimal secondary pollution, making it an increasingly promising application in the treatment of recalcitrant organic wastewater. However, current catalytic ozonation processes still suffer from low gas-liquid mass transfer efficiency and low ozone utilization. According to Henry's law, the solubility of a gas in an aqueous solution is positively correlated with its pressure. Therefore, by pressurizing the dissolved gas to increase ozone solubility, the conventional gas-liquid heterogeneous oxidation process can be converted to a liquid-liquid homogeneous oxidation process, thereby improving the efficiency and utilization of the ozone oxidation reaction and enhancing the treatment of coking wastewater. Summary of the Invention

[0004] The present invention aims to address the problems of low mass transfer efficiency and low ozone utilization in the prior art by providing a device and operating method for deep treatment of coking wastewater by pressurizing and enhancing the catalytic oxidation capacity of ozone. The technical solution is as follows:

[0005] A coking wastewater ozone catalytic oxidation deep treatment device, characterized in that it comprises a pure oxygen storage tank (20), an ozone generator (19), an ozone compressor (18), an ozone catalytic oxidation tank B (12) and an ozone catalytic oxidation tank A (5) connected in sequence, wherein the ozone catalytic oxidation tank A (5) is provided with two independent ozone catalytic oxidation tank A circulating water inlets (8) and an ozone catalytic oxidation tank A water inlet (4) on the lower side, and an ozone catalytic oxidation tank A outlet (7) on the upper side; the ozone catalytic oxidation tank B (12) is provided with two independent ozone catalytic oxidation tank B circulating water outlets (11) and an ozone catalytic oxidation tank B outlet (15) on the upper side, and two independent ozone catalytic oxidation tank B outlets (16) on the lower side. The ozone catalytic oxidation tank B water inlet (10) and the ozone catalytic oxidation tank B ozone air inlet (14); the pure oxygen storage tank (20), the ozone generator (19), the ozone compressor (18) and the ozone catalytic oxidation tank B ozone air inlet (14) are sequentially connected through an ozone pipeline; the wastewater to be treated is connected to a high-pressure pump (1), the high-pressure pump (1) is connected to the ozone catalytic oxidation tank A water inlet (4) through a liquid flow meter and a valve through a sewage pipeline, the ozone catalytic oxidation tank A water outlet (7) is connected to the ozone catalytic oxidation tank B water inlet (10) through a valve, and the ozone catalytic oxidation tank B circulating water outlet (11) is connected to the ozone catalytic oxidation tank A circulating water inlet (8) through a valve, a circulating pump (9) and a liquid flow meter.

[0006] The ozone catalytic oxidation tank B (12) and the ozone catalytic oxidation tank A (5) are connected via a sewage pipe; the sewage pipe and the ozone pipe are equipped with one or more valves, liquid flow meters or gas flow meters as needed to monitor flow and control pressure.

[0007] The ozone catalytic oxidation tank A (5) and the ozone catalytic oxidation tank B (12) are both provided with a safety valve (6) on the top to ensure a safe pressure state during operation. A solid catalyst support layer (17) is provided near the bottom of each tank, and a solid catalyst is placed thereon. An ozone aeration disk (13) is provided below the solid catalyst support layer (17) of the ozone catalytic oxidation tank B. The aeration disk (13) is connected to the ozone compressor (18) via an ozone pipe and an ozone catalytic oxidation tank B ozone inlet (14). An ozone catalytic oxidation tank B water outlet (15) is also provided on the upper side of the ozone catalytic oxidation tank B for discharging sewage. The ozone catalytic oxidation tank B water inlet (10) is located between the solid catalyst support layer (17) and the aeration disk (13).

[0008] The lower part of the ozone catalytic oxidation tank B and the lower part of the ozone catalytic oxidation tank A both refer to positions below the solid catalyst supporting layer (17).

[0009] In addition, an ozone catalytic oxidation tank B water inlet (10) is provided on the lower side of the ozone catalytic oxidation tank B (12), which is connected to the ozone catalytic oxidation tank A water outlet (7). An ozone catalytic oxidation tank B ozone air inlet (14) is also provided on the lower side of the ozone catalytic oxidation tank B (12), which is used to connect the ozone pipeline. An oxygen catalytic oxidation tank B circulating water outlet (11) is provided on the upper side of the ozone catalytic oxidation tank B (12), which is connected to the water inlet of the circulation pump (9). The oxygen catalytic oxidation tank B circulating water outlet is connected to the circulation pump (9) and the ozone catalytic oxidation tank A circulating water inlet (8), thereby forming a circulation system of the device.

[0010] Specifically, the coking wastewater ozone catalytic oxidation deep treatment device operates as follows: the coking wastewater treated by physical and biological methods is sent into the ozone catalytic oxidation tank A through a high-pressure pump, and the wastewater is made to flow from the ozone catalytic oxidation tank A into the ozone catalytic oxidation tank B. When sewage flows into the ozone catalytic oxidation tank B, pressurized high-pressure ozone gas is introduced into the ozone catalytic oxidation tank B. The ozone dissolved in the sewage in the tank B first degrades the organic pollutants in the first step under the synergistic action of the solid catalyst, and then is sent back to the A tank through a circulation pump. In the ozone catalytic oxidation tank A, the remaining ozone in the water body degrades the organic pollutants in the second step under the synergistic action of the solid catalyst. This cycle is repeated until the sewage in the ozone catalytic oxidation tank B reaches the discharge effect and is discharged from the water outlet (15) of the ozone catalytic oxidation tank B.

[0011] The present application has no special limitation on the solid catalyst, as long as it can achieve the degradation of the present application.

[0012] The beneficial effects brought about by the technical solution provided by the present invention are:

[0013] The coking wastewater ozone catalytic oxidation deep treatment device provided by the present invention, through the sequentially connected pure oxygen storage tank, ozone generator, ozone compressor, ozone catalytic oxidation tank B and ozone catalytic oxidation tank A, uses high-concentration ozone to degrade low-concentration organic pollutants in the ozone catalytic oxidation tank B, thereby achieving complete degradation of organic pollutants. At the same time, low-concentration ozone is used in the ozone catalytic oxidation tank A to degrade high-concentration organic pollutants, thereby achieving efficient utilization of ozone, and ultimately enabling the effluent to meet discharge standards. The recycling process of using high-concentration ozone to degrade low-concentration organic pollutants and using low-concentration ozone to degrade high-concentration organic pollutants solves the problems of large ozone tail gas emissions, low ozone utilization rate, and difficulty in degrading organic pollutants in coking wastewater, reduces ozone waste, improves the effective utilization rate of ozone, and avoids the problem of ozone tail gas treatment, reduces the cost of sewage treatment, and improves economic practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1This is a structural schematic diagram of the coking wastewater ozone catalytic oxidation deep treatment device provided by the present invention.

[0015] Among them, 1 is a high-pressure pump; 2 is a liquid flow meter; 3 is a valve; 4 is the water inlet of ozone catalytic oxidation tank A; 5 is the body of ozone catalytic oxidation tank A; 6 is a safety valve; 7 is the water outlet of ozone catalytic oxidation tank A; 8 is the circulating water inlet of ozone catalytic oxidation tank A; 9 is a circulating pump; 10 is the water inlet of ozone catalytic oxidation tank B; 11 is the circulating water outlet of ozone catalytic oxidation tank B; 12 is the body of ozone catalytic oxidation tank B; 13 is the ozone aeration plate; 14 is the ozone air inlet of ozone catalytic oxidation tank B; 15 is the water outlet of ozone catalytic oxidation tank B; 16 is a gas flow meter; 17 is the solid catalyst support layer; 18 is the ozone compressor; 19 is the ozone generator; 20 is the pure oxygen storage tank. DETAILED DESCRIPTION

[0016] The present invention will be further described below with reference to the accompanying drawings.

[0017] As attached Figure 1 As shown, the present invention provides a coking wastewater ozone catalytic oxidation deep treatment device, which includes a pure oxygen storage tank 20, an ozone generator 19, an ozone compressor 18, an ozone catalytic oxidation tank B 12, and an ozone catalytic oxidation tank A 5, which are connected in sequence. The pure oxygen storage tank 20, ozone generator 19, ozone compressor 18, and ozone catalytic oxidation tank B 12 are connected in sequence through an ozone pipeline, and the ozone catalytic oxidation tank A 5 is connected in sequence to the ozone catalytic oxidation tank B 12 through a sewage pipeline. Valves 3 and liquid flow meters 2 or gas flow meters 16 are installed on both the sewage pipeline and the ozone pipeline for monitoring flow and controlling pressure.

[0018] Both the ozone catalytic oxidation tank A 5 and tank B 12 are equipped with safety valves 6 at the top to ensure a safe pressure state during operation. A solid catalyst support layer 17 is provided near the bottom of the tank for placement of the solid catalyst. Specifically, a water inlet 4 is provided on the side of the bottom of the ozone catalytic oxidation tank A, which is connected to the valve 3, liquid flowmeter 2, and the outlet of the high-pressure pump 1 in sequence through a sewage pipe. A water outlet 7 is provided on the upper side of tank A for draining sewage to tank B. A circulating water inlet 8 is also provided on the side of the bottom of tank A, which is connected to the outlet of the circulating pump 9. An ozone aeration plate 13 is provided at the lower part of the solid catalyst supporting layer 17 of the ozone catalytic oxidation tank B. The aeration plate 13 is connected to the ozone compressor 18 through an ozone pipe. In addition, a water inlet 10 is provided on the bottom side of the B tank, which is connected to the water outlet 7 of the A tank. An ozone inlet 14 is also provided on the bottom side of the B tank for connecting to the ozone pipe. A circulating water outlet 11 is provided on the upper side of the B tank, which is connected to the water inlet of the circulating pump 9. The circulating water outlet 11 of the B tank is connected to the circulating pump 9 and the circulating water inlet 8 of the A tank, forming a circulation system of the device. A water outlet 15 is also provided on the upper side of the B tank for discharging sewage.

[0019] The coking wastewater ozone catalytic oxidation deep treatment device comprises a pure oxygen storage tank, an ozone generator, an ozone compressor, an ozone catalytic oxidation tank B and an ozone catalytic oxidation tank A which are connected in sequence.

[0020] Specifically, the pure oxygen storage tank, ozone generator, ozone compressor and ozone catalytic oxidation tank B are connected in sequence through an ozone pipe, and the ozone catalytic oxidation tank A is connected in sequence with the ozone catalytic oxidation tank B through a sewage pipe.

[0021] Specifically, the coking wastewater ozone catalytic oxidation deep treatment device also includes a high-pressure pump connected to the water inlet of ozone catalytic oxidation tank A, a circulation pump connected to the return sewage pipeline between ozone catalytic oxidation tank B and ozone catalytic oxidation tank A, and several valves. The valves include at least five valves, all installed on the sewage pipeline and the ozone pipeline, for regulating flow and pressure.

[0022] Specifically, the ozone catalytic oxidation tank A includes a cylindrical tank body, a solid-phase catalyst bed, a pressure safety valve, a water inlet and a water outlet. The pressure safety valve is arranged at the top of the tank body, and the water inlets include a sewage inlet and a circulating water inlet, which are respectively arranged on both sides symmetrically on the bottom side of the tank body, and the sewage inlet is connected to the high-pressure pump outlet through a sewage pipe, and the circulating water inlet is connected to the circulating pump outlet through a sewage pipe. The water outlet is arranged on the upper side of the tank body, and the water outlet will be connected to the water inlet of the ozone catalytic oxidation tank B through the sewage pipe.

[0023] Specifically, the ozone catalytic oxidation tank B includes a cylindrical tank body, a solid catalyst bed, a pressure safety valve, a water inlet, a water outlet, an air inlet and an ozone aeration plate. The pressure safety valve is arranged at the top of the tank body, the ozone aeration plate is arranged at the lower part of the solid catalyst bed in the tank body, and the ozone aeration plate is connected to the air inlet through an ozone pipe. The water inlet is arranged on the bottom side of the tank body, and the water inlet is connected to the water outlet of the ozone catalytic oxidation tank A through a sewage pipe. The air inlet is arranged on the bottom side symmetrically with the water inlet, and the air inlet is connected to the air outlet box of the ozone compressor through the ozone pipe. The water outlet includes a circulating water outlet and a sewage drain, and the circulating water outlet is connected to the water inlet of the circulating pump through a sewage pipe. The sewage drain is used to discharge the sewage from the ozone catalytic oxidation tank B.

[0024] Specifically, the ozone catalytic oxidation tank, ozone compressor, sewage pipe, ozone pipe and valve are all made of corrosion-resistant and oxidation-resistant materials.

[0025] The specific operation process is as follows:

[0026] First, open the valve connected to high-pressure pump 1. Turn on high-pressure pump 1, allowing the wastewater to flow through liquid flowmeter 2 and valve into ozone catalytic oxidation tank A 5. Once the water level in tank A rises, the wastewater is fed into ozone catalytic oxidation tank B 12. Once the water level in tank B rises, turn on circulation pump 9 to allow the wastewater to begin circulating. At this point, oxygen from pure oxygen storage tank 20 is passed into ozone generator 19. The generated ozone is pressurized to 0.3-0.6 MPa by ozone compressor 18 and then passed through gas flowmeter 16 and valve 3. It is then fed into tank B through air inlet 14 on the bottom side of tank B. The ozone dosage in tank B is 400-600 mg / L. At this point, the coking wastewater and saturated dissolved ozone water, synergistically acting with the solid catalyst, perform the first step of degrading organic pollutants. The coking wastewater that has completed the first step of degradation is fed into Tank A from the circulating water outlet 11 of Tank B through the circulating water inlet 8 of Tank A under the action of the circulating pump 9. At this time, the circulating water still contains a small amount of dissolved ozone that has not yet reacted. This reacts with the untreated coking wastewater continuously fed into Tank A in the second step of degradation, completely consuming the remaining dissolved ozone. Afterwards, the coking wastewater with some organic pollutants already degraded is re-fed into Tank B to react with the sufficient dissolved ozone to completely degrade the remaining organic pollutants. Through the circulating treatment, while achieving complete degradation of organic pollutants, it also achieves efficient utilization of ozone, solving the problems of large ozone tail gas emissions, low ozone utilization rate, and the difficulty in degrading organic pollutants in the coking wastewater.

[0027] The solid catalyst used in the following Examples 1-3 is activated alumina, which may also be replaced by other solid catalysts in the art.

[0028] Example 1:

[0029] A sewage treatment plant treats coking wastewater through a combination of sedimentation, AAO, and HBAF processes, but the COD of the sewage at the discharge end is cr The value is still between 180-220 mg / L, which fails to meet the national urban sewage discharge standard. Therefore, the coking wastewater ozone catalytic oxidation deep treatment device provided by the present invention is used to further treat it. The specific operation process is as follows:

[0030] First, coking wastewater is pumped into ozone catalytic oxidation tank A using a high-pressure pump. After the water level is raised, it flows into tank B. The circulation pump is turned on to circulate the coking wastewater. Simultaneously, the pure oxygen storage tank is opened, allowing pure oxygen gas to flow into the ozone generator. The generated ozone is pressurized to 0.4 MPa by the ozone compressor and then passed from the bottom into ozone catalytic oxidation tank B. The ozone dosage is 500 mg / L. The fluids in both tanks A and B flow from bottom to top, passing through the solid catalyst bed that accounts for 30% of the tank volume. Valves control the wastewater and ozone flow rates, as well as the pressure in the reactor. Under the high pressure, the ozone gas in tank B fully dissolves in the coking wastewater. With the synergistic effect of the solid catalyst, the dissolved ozone performs the first step of degrading the difficult-to-degrade organic pollutants in the coking wastewater. The unreacted dissolved ozone flows into tank A through the circulation pump along the circulation route for the second step of degradation, reacts with the newly fed coking wastewater, and consumes the remaining ozone completely. The coking wastewater with some degraded organic pollutants is then sent to tank B to react with sufficient dissolved ozone to achieve full degradation of organic pollutants. The hydraulic retention time is 30 minutes, and the final effluent COD cr The value is between 35 and 41 mg / L, which meets the national urban sewage discharge standard.

[0031] Example 2:

[0032] Example 2 used the same coking wastewater as Example 1, but changed the volume of the solid catalyst bed in tanks A and B of the ozone catalytic oxidation to 20%, the ozone dosage to 400 mg / L, the operating pressure to 0.3 MPa, and the hydraulic retention time to 50 min. Under these conditions, the coking wastewater was treated as follows:

[0033] The high-pressure pump is turned on to feed the coking wastewater into Tank A, where it flows through the sewage pipe into Tank B. When the water level in Tank B reaches a certain level, the circulation pump is turned on to circulate the coking wastewater back into the tank. The pure oxygen storage tank is then opened to allow pure oxygen to flow into the ozone generator. The generated ozone is pressurized to 0.3 MPa by the ozone compressor and then fed from the bottom into Tank B, where the ozone dosage is 400 mg / L. Valves control the wastewater and ozone flow rates, as well as the pressure in the reactor. Under the high pressure, the ozone in Tank B is fully dissolved in the coking wastewater. With the synergistic effect of the solid catalyst, the dissolved ozone performs the first step of degradation of the recalcitrant organic pollutants in the coking wastewater. Unreacted dissolved ozone flows through the circulation pump into Tank A for the second step of degradation, where it reacts with the newly introduced coking wastewater, completely consuming any remaining ozone. The coking wastewater with partially degraded organic pollutants is then fed back into Tank B to react with the abundant dissolved ozone, achieving complete degradation of the organic pollutants. Hydraulic retention time 50min, final effluent COD cr The value is 48mg / L, which basically meets the national urban sewage discharge standards.

[0034] Example 3:

[0035] Example 3 used the same coking wastewater as Example 1, but changed the volume of the solid catalyst bed in the ozone catalytic oxidation tank A and tank B to 30%, the ozone dosage to 600 mg / L, the operating pressure to 0.6 MPa, and the hydraulic retention time to 40 min. Under these conditions, the coking wastewater was treated as follows:

[0036] First, open the valve and start the high-pressure pump, allowing the wastewater to be fed sequentially through the liquid flow meter and valve into the ozone catalytic oxidation tank A. Once the water level in tank A rises, the wastewater is fed into the ozone catalytic oxidation tank B. Once the water level in tank B rises, turn on the circulation pump to allow the wastewater to circulate internally. At this time, the oxygen in the pure oxygen storage tank is passed into the ozone generator. The generated ozone is pressurized to 0.6MPa by the ozone compressor and then passed through the gas flow meter and valve, and fed into the tank from the air inlet on the bottom side of tank B. At this point, the coking wastewater and saturated dissolved ozone water, under the synergistic action of the solid catalyst, carry out the first step of degradation of organic pollutants. The coking wastewater that has completed the first step of degradation flows from the circulating water outlet of tank B through the circulating water inlet of tank A into tank A under the action of the circulating pump. At this time, the circulating water still contains a small amount of dissolved ozone that has not yet reacted. It undergoes the second step of degradation reaction with the untreated coking wastewater continuously fed into tank A, completely consuming the remaining dissolved ozone. Afterwards, the coking wastewater with some organic pollutants that have been degraded is re-sent into tank B to react with sufficient dissolved ozone to completely degrade the remaining organic pollutants. The ozone dosage is 600mg / L, the hydraulic retention time is 40min, and the final effluent COD cr The value is 32mg / L, which meets the national urban sewage discharge standard.

[0037] The recycling process of using high-concentration ozone to degrade low-concentration organic pollutants and low-concentration ozone to degrade high-concentration organic pollutants solves the problems of large ozone tail gas emissions, low ozone utilization rate and difficult degradation of organic pollutants in coking wastewater, reduces ozone waste, improves the effective utilization rate of ozone, and saves time.

[0038] The principles and implementation methods of the present invention have been described in detail above to help understand the core idea of ​​the present invention. Those skilled in the art will appreciate that modifications and improvements may be made to the present invention without departing from the principles of the present invention, and such modifications and improvements fall within the scope of protection of the present invention.

Claims

1. A method for deep treatment of coking wastewater by ozone catalytic oxidation, characterized in that: The device used includes a connected pure oxygen storage tank (20), an ozone generator (19), an ozone compressor (18), an ozone catalytic oxidation tank B (12) and an ozone catalytic oxidation tank A (5), wherein the ozone catalytic oxidation tank A (5) is provided with two independent ozone catalytic oxidation tank A circulating water inlets (8) and an ozone catalytic oxidation tank A water inlet (4) on the lower side, and an ozone catalytic oxidation tank A outlet (7) on the upper side, and the ozone catalytic oxidation tank A water inlet (4) and the ozone catalytic oxidation tank A circulating water inlet (8) are respectively provided on both sides of the bottom side of the tank body; the ozone catalytic oxidation tank B (12) The upper side is provided with two independent ozone catalytic oxidation tank B circulating water outlets (11) and ozone catalytic oxidation tank B outlets (15), and the lower side is provided with two independent ozone catalytic oxidation tank B water inlets (10) and ozone catalytic oxidation tank B ozone air inlets (14), respectively. The ozone catalytic oxidation tank B ozone air inlets (14) are provided on the bottom side and on the side opposite to the ozone catalytic oxidation tank B water inlet (10); the pure oxygen storage tank (20), the ozone generator (19), the ozone compressor (18) and the ozone catalytic oxidation tank B ozone air inlet (14) are connected in sequence through an ozone pipeline; The wastewater to be treated is connected to a high-pressure pump (1), which is connected to the water inlet (4) of the ozone catalytic oxidation tank A via a liquid flow meter and a valve through a sewage pipe. The water outlet (7) of the ozone catalytic oxidation tank A is connected to the water inlet (10) of the ozone catalytic oxidation tank B via a valve. Meanwhile, the circulating water outlet (11) of the ozone catalytic oxidation tank B is connected to the circulating water inlet (8) of the ozone catalytic oxidation tank A via a valve, a circulating pump (9), and a liquid flow meter. An ozone catalytic oxidation tank B water inlet (10) is provided on the lower side of the ozone catalytic oxidation tank B (12), which is connected to the ozone catalytic oxidation tank A water outlet (7). An ozone catalytic oxidation tank B ozone air inlet (14) is also provided on the lower side of the ozone catalytic oxidation tank B (12), which is used to connect the ozone pipeline. An ozone catalytic oxidation tank B circulating water outlet (11) is provided on the upper side of the ozone catalytic oxidation tank B (12), which is connected to the water inlet of the circulation pump (9). The ozone catalytic oxidation tank B circulating water outlet is connected to the circulation pump (9) and the ozone catalytic oxidation tank A circulating water inlet (8), thereby forming a circulation system. The deep processing method includes the following steps: First, open the valve connected to the high-pressure pump, turn on the high-pressure pump, and send the sewage into the ozone catalytic oxidation tank A through the liquid flow meter and valve in sequence. After the water level in tank A rises, the sewage is sent to the ozone catalytic oxidation tank B. After the water level in tank B rises, turn on the circulation pump to allow the sewage to start internal circulation. At this time, the oxygen in the pure oxygen storage tank is introduced into the ozone generator. The generated ozone is pressurized to 0.3-0.6MPa by the ozone compressor and then passed through the gas flow meter and valve in sequence. It is sent into tank B from the air inlet on the bottom side of tank B. The ozone dosage of tank B is 400-600mg / L; at this time, the coking wastewater and the saturated dissolved ozone water, under the synergistic action of the solid catalyst, carry out the first step of degradation of organic pollutants; the coking wastewater that has completed the first step of degradation flows into tank A from the circulating water outlet of tank B through the circulating water inlet of tank A under the action of the circulation pump. At this time, the circulating water still contains unreacted A small amount of dissolved ozone is used to carry out the second step degradation reaction with the untreated coking wastewater continuously fed into tank A, and the remaining dissolved ozone is completely consumed. After that, the coking wastewater with some organic pollutants degraded is re-sent into tank B to react with sufficient dissolved ozone to completely degrade the remaining organic pollutants; high-concentration ozone is used to degrade low-concentration organic pollutants in the ozone catalytic oxidation tank B, thereby achieving complete degradation of organic pollutants. At the same time, low-concentration ozone is used to degrade high-concentration organic pollutants in the ozone catalytic oxidation tank A, thereby achieving efficient utilization of ozone; the recycling process of using high-concentration ozone to degrade low-concentration organic pollutants and using low-concentration ozone to degrade high-concentration organic pollutants not only achieves complete degradation of organic pollutants, but also achieves efficient utilization of ozone, solving the problems of large ozone tail gas emissions, low ozone utilization rate and difficult degradation of organic pollutants in coking wastewater.

2. The method for deep treatment of coking wastewater by ozone catalytic oxidation according to claim 1, characterized in that: The ozone catalytic oxidation tank B (12) and the ozone catalytic oxidation tank A (5) are connected via a sewage pipe; the sewage pipe and the ozone pipe are equipped with one or more valves, liquid flow meters or gas flow meters as needed to monitor flow and control pressure.

3. The method for deep treatment of coking wastewater by ozone catalytic oxidation according to claim 1, characterized in that: The ozone catalytic oxidation tank A (5) and the ozone catalytic oxidation tank B (12) are both provided with a safety valve (6) at the top to ensure a safe pressure state during operation. A solid catalyst supporting layer (17) is provided near the bottom of each tank, and a solid catalyst is placed thereon. An ozone aeration plate (13) is provided below the solid catalyst supporting layer (17) of the ozone catalytic oxidation tank B. The aeration plate (13) is connected to the ozone compressor (18) via an ozone pipe and an ozone catalytic oxidation tank B ozone air inlet (14). An ozone catalytic oxidation tank B water outlet (15) is also provided on the upper side of the ozone catalytic oxidation tank B for discharging sewage.

4. The method for deep treatment of coking wastewater by ozone catalytic oxidation according to claim 3, characterized in that: The water inlet (10) of the ozone catalytic oxidation tank B is located between the solid catalyst support layer (17) and the aeration plate (13).

5. The method for deep treatment of coking wastewater by ozone catalytic oxidation according to claim 3, characterized in that: The lower part of the ozone catalytic oxidation tank B and the lower part of the ozone catalytic oxidation tank A both refer to positions below the solid catalyst supporting layer (17).

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