Integrated device and process for heterogeneous ozonation advanced oxidation of sulfur-containing wastewater

Abstract

The present application relates to the technical field of sulfur-containing sewage treatment of gas field, and discloses a sulfur-containing sewage heterogeneous ozone advanced oxidation integrated treatment device and process. The device has a structure of a sewage buffer tank and an ozone oxidation reactor, and utilizes the liquid level fluctuation in the buffer tank to ensure the relative stability of the liquid amount of the subsequent process. The sewage in the buffer tank is transported to the ozone oxidation reactor by a sewage lifting pump, and the sulfur-containing sewage is subjected to advanced oxidation reaction with ozone under the action of a catalyst, so that the sulfur ions in the sulfur-containing sewage are rapidly oxidized into SO 2‑ ions, thereby achieving the purposes of purifying the sewage and eliminating odor. Since a selenium-rich catalyst is used, it can be used for a long time after being added once. In addition, under the action of the selenium-rich catalyst, the catalyst catalyzes the ozone to generate ·OH (hydroxyl radicals), which has extremely strong oxidation ability and no selectivity, so as to promote the advanced oxidation of sulfides in the sewage with ozone, thereby achieving more thorough oxidation and higher ozone utilization rate. Finally, the device has small investment and small land occupation.

Description

Technical Field

[0001] This invention relates to the field of sulfur-containing wastewater treatment technology in gas fields, specifically to an integrated treatment device and process for heterogeneous ozone advanced oxidation of sulfur-containing wastewater. Background Technology

[0002] Sulfur-containing gas fields generate large amounts of sulfur-containing wastewater during development and production, causing soil pollution and pipeline corrosion. Furthermore, the H2S gas emitted from the wastewater poses health risks and pollutes the environment. Therefore, sulfur-containing wastewater cannot be directly discharged and must be treated to meet discharge or reinjection standards. Currently, there are many methods for treating sulfur-containing wastewater, such as air oxidation, chemical precipitation, and air stripping. Air oxidation has good treatment effects, but requires high temperature and high pressure conditions, resulting in high energy consumption and high construction and operating costs. Chemical precipitation involves adding ferrous or ferric salts to the wastewater to form insoluble substances for removal; however, when the sulfur content in the wastewater is high, the system produces a large amount of sludge, leading to high treatment costs. Air stripping involves countercurrent contact between the stripping gas and wastewater in a stripping tower, reducing the partial pressure of H2S within the tower and accelerating the desorption of H2S from the wastewater to achieve desulfurization. This method is greatly affected by pressure, pH value, and gas-liquid mass transfer, and its desulfurization effect is poor when the pH value of the sulfur-containing wastewater is high. Summary of the Invention

[0003] To address the aforementioned shortcomings of existing technologies, an integrated treatment device and process for heterogeneous ozone advanced oxidation of sulfur-containing wastewater is provided. This device is suitable for desulfurization treatment of sulfur-containing produced water from sulfur-containing gas fields and can solve problems such as high energy consumption, high investment and operating costs, and poor desulfurization effect.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0005] An integrated treatment device for heterogeneous ozone advanced oxidation of sulfur-containing wastewater is characterized by comprising: a wastewater buffer tank connected to an external sulfur-containing wastewater pipeline; an ozone oxidation reactor connected to the wastewater buffer tank via a pipeline; and a tail gas processor and an ozone generator connected to the ozone oxidation reactor; the ozone oxidation reactor is connected to an external drainage pipeline, and a selenium-enriched catalyst is provided inside the ozone oxidation reactor; a wastewater lift pump is provided between the pipelines of the ozone oxidation reactor and the wastewater buffer tank.

[0006] According to the above technical solution, the connection between the exhaust gas processor and the ozone oxidation reactor is located at the top of the ozone oxidation reactor; the connection between the external drain pipe and the ozone oxidation reactor is located on the upper part of the side wall of the ozone oxidation reactor, and the connection between the external drain pipe and the ozone oxidation reactor is lower than the connection between the exhaust gas processor and the ozone oxidation reactor; the connection between the ozone generator and the ozone oxidation reactor, as well as the connection between the sewage buffer tank and the ozone oxidation reactor, are all located on the lower part of the side wall of the ozone oxidation reactor.

[0007] According to the above technical solution, the ozone oxidation reactor includes a tank and a catalyst packing located inside the tank. The catalyst packing is located in the middle of the tank and divides the tank into upper and lower spaces. An ozone exhaust gas outlet connected to the exhaust gas processor is provided at the top of the tank. A liquid drain is provided on the side of the upper space. A sewage drain is provided at the bottom of the tank. A sewage inlet and an ozone inlet are provided on the side wall of the lower space. The ozone inlet adopts a lotus-shaped structure with several upward-facing pores spaced apart on the lotus-shaped structure.

[0008] According to the above technical solution, the selenium-enriched catalyst uses a catalyst with selenium supported by aluminum and titanium oxides, and the catalyst adopts a spherical structure.

[0009] According to the above technical solution, sewage discharge pipelines are installed at the bottom of both the sewage buffer tank and the ozone oxidation generator.

[0010] According to the above technical solution, a sewage flow meter is installed on the pipeline between the sewage buffer tank and the ozone oxidation reactor, and an ozone flow meter is installed on the pipeline between the ozone generator and the ozone oxidation reactor.

[0011] A heterogeneous ozone advanced oxidation treatment process for sulfur-containing wastewater is characterized by: adjusting the pH value of the sulfur-containing wastewater to a range of 8.0–10.0; subsequently, simultaneously introducing the sulfur-containing wastewater and ozone into a tank containing a selenium-enriched catalyst to carry out an advanced oxidation-reduction reaction, based on the sulfur content in the wastewater... 2- The concentration of ozone is adjusted by controlling the concentration of ozone introduced into the wastewater. During this process, the liquid inlet pressure is maintained at 0.1 MPa to 0.2 MPa. A selenium-rich catalyst is used to catalyze the generation of hydroxyl radicals from the ozone, thereby removing sulfur dioxide from the wastewater. 2- Oxidized to SO 2- .

[0012] According to the above technical solution, based on the S content of sulfur-containing wastewater from the gas field 2- The concentration and flow rate of ozone are controlled to maintain the ozone concentration at 25 mg / L to 35 mg / L. In addition to controlling the concentration of introduced ozone, the flow rates of wastewater and ozone entering the tank are controlled using wastewater flow meters and ozone flow meters within the device, thus controlling the concentration of ozone within the reaction tank. 2- And the amount of ozone.

[0013] According to the above technical solution, the optimal operating conditions of this process are a pH of 9.0 for sulfur-containing wastewater, an ozone concentration of 30 mg / L, and a liquid phase inlet pressure of 0.15 MPa.

[0014] The present invention has the following beneficial effects:

[0015] 1. The system adopts a structure of a wastewater buffer tank + ozone oxidation reactor. The wastewater buffer tank smooths out liquid level fluctuations within the tank, ensuring a relatively stable influent flow rate to subsequent processes. A wastewater lift pump transports wastewater from the buffer tank to the ozone oxidation reactor. Under the action of a catalyst, the sulfur-containing wastewater undergoes an advanced oxidation reaction with ozone, rapidly oxidizing sulfur ions in the wastewater into SO₂. 2- Ions are used to purify wastewater and eliminate odors. The purified wastewater is discharged from the external drain pipe connected to the ozone oxidation reactor. The tail gas emitted by the ozone oxidation reactor is ozone. Through the tail gas processor connected to the ozone oxidation generator, the ozone can be decomposed into oxygen and then released into the atmosphere without polluting the environment.

[0016] Based on the above measures, wastewater is connected to the integrated heterogeneous ozone advanced oxidation treatment device for sulfur-containing wastewater of this invention. The selenium-enriched catalyst and ozone oxidize sulfur ions within the ozone oxidation reactor, thereby achieving wastewater purification. Because a selenium-enriched catalyst is used, it can be used for a long time with a single addition, requiring replacement only every 3-5 years. Secondly, under the action of the selenium-enriched catalyst, ozone is catalyzed to produce ·OH (hydroxyl radicals), which have extremely strong and non-selective oxidizing power, promoting advanced oxidation of sulfides in wastewater with ozone, resulting in more thorough oxidation and higher ozone utilization. Finally, the equipment investment of this invention is small, and it occupies a small area.

[0017] 2. The optimal operating conditions for this process are: pH 9.0 for sulfur-containing wastewater, ozone concentration 30 mg / L, and liquid phase inlet pressure 0.15 MPa. Based on this process, under optimal operating conditions, S 2- The removal rate can reach over 99%, and the treated wastewater contains less sulfur. 2- The purification effect is significant when the concentration is below 0.5 mg / L. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of an embodiment provided by the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of the ozone oxidation reactor provided in an embodiment of the present invention;

[0020] In the diagram, 1. Sulfur wastewater pipeline; 2. Wastewater buffer tank; 3. Ozone oxidation reactor; 3-1. Tank body; 3-2. Catalyst packing; 3-3. Ozone tail gas outlet; 3-4. Drain outlet; 3-5. Sewage outlet; 3-6. Wastewater inlet; 3-7. Ozone inlet; 4. Tail gas processor; 5. Ozone generator; 6. Wastewater lift pump; 7. Sewage pipeline; 8. Wastewater flow meter; 9. Ozone flow meter. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] Reference Figures 1-2 As shown, the present invention provides an integrated treatment device for heterogeneous ozone advanced oxidation of sulfur-containing wastewater.

[0023] Example 1

[0024] It includes a sewage buffer tank 2 connected to an external sulfur-containing sewage pipeline 1, an ozone oxidation reactor 3 connected to the sewage buffer tank via a pipeline, and a tail gas processor 4 and an ozone generator 5 connected to the ozone oxidation reactor; the ozone oxidation reactor is connected to an external drainage pipeline, and a selenium-enriched catalyst is installed inside the ozone oxidation reactor; a sewage lift pump 6 is installed between the pipelines between the ozone oxidation reactor and the sewage buffer tank.

[0025] In this embodiment, a wastewater buffer tank + ozone oxidation reactor structure is adopted. The wastewater buffer tank smooths out liquid level fluctuations within the tank, ensuring a relatively stable influent flow rate for subsequent processes. A wastewater lift pump transports the wastewater from the buffer tank to the ozone oxidation reactor. Under the action of a catalyst, the sulfur-containing wastewater undergoes an advanced oxidation reaction with ozone, rapidly oxidizing sulfur ions in the wastewater into SO₂. 2- The ozone generator uses ions to purify wastewater and eliminate odors. The purified wastewater is discharged from the external drain pipe connected to the ozone oxidation reactor. The ozone emitted by the ozone oxidation reactor is ozone. Through the exhaust gas processor connected to the ozone oxidation generator, the ozone can be decomposed into oxygen and then released into the atmosphere without polluting the environment.

[0026] Based on the above measures, wastewater is connected to the integrated heterogeneous ozone advanced oxidation treatment device for sulfur-containing wastewater of this invention. The selenium-enriched catalyst and ozone oxidize sulfur ions within the ozone oxidation reactor, thereby achieving wastewater purification. Because a selenium-enriched catalyst is used, it can be used for a long time with a single addition, requiring replacement only every 3-5 years. Secondly, under the action of the selenium-enriched catalyst, ozone is catalyzed to produce ·OH (hydroxyl radicals), which have extremely strong and non-selective oxidizing power, promoting advanced oxidation of sulfides in wastewater with ozone, resulting in more thorough oxidation and higher ozone utilization. Finally, the equipment investment of this invention is small, and it occupies a small area.

[0027] Based on the above embodiments, a preferred arrangement of the treatment device is provided. Specifically, the connection between the exhaust gas processor and the ozone oxidation reactor is located at the top of the ozone oxidation reactor; the connection between the external drain pipe and the ozone oxidation reactor is located on the upper part of the side wall of the ozone oxidation reactor, and the connection between the external drain pipe and the ozone oxidation reactor is lower than the connection between the exhaust gas processor and the ozone oxidation reactor; the connection between the ozone generator and the ozone oxidation reactor, as well as the connection between the wastewater buffer tank and the ozone oxidation reactor, are all located on the lower part of the side wall of the ozone oxidation reactor.

[0028] In this embodiment, the height of the connection between the external drain pipe and the ozone oxidation reactor is the height inside the ozone oxidation reactor. The height of the connection between the ozone generator and the wastewater buffer tank and the ozone oxidation reactor is both below the liquid surface. The ozone entering from the ozone generator and the sulfur-containing wastewater entering from the wastewater buffer tank work together with the selenium-rich catalyst in the area below the liquid surface to undergo advanced oxidation.

[0029] Example 2

[0030] The structure and principle of Example 2 are similar to those of Example 1, except that the ozone oxidation reactor includes a tank 3-1 and a catalyst packing 3-2 located inside the tank. The catalyst packing is located in the middle of the tank and divides the tank into upper and lower spaces. An ozone exhaust gas outlet 3-3 connected to the exhaust gas processor is provided at the top of the tank. A drain outlet 3-4 is provided on the side of the upper space. A sewage outlet 3-5 is provided at the bottom of the tank. A sewage inlet 3-6 and an ozone inlet 3-7 are provided on the side wall of the lower space. The ozone inlet adopts a lotus-shaped structure with several upward-facing pores spaced apart on the lotus-shaped structure.

[0031] In the ozone oxidation reactor structure described in this embodiment, sulfur-containing wastewater enters through the wastewater inlet in the lower space, overflows the catalyst packing, and is discharged through the drain outlet. Ozone enters the tank through the ozone inlet, is evenly mixed into the wastewater by the lotus-shaped structure, and floats to the surface. During this process, the ozone is catalyzed by the catalyst packing to generate ·OH (hydroxyl radicals), which promotes the advanced oxidation of sulfides in the wastewater, thereby achieving the purpose of purifying the wastewater. During this process, residual solid impurities in the wastewater deposit at the bottom of the tank and are discharged through the drain outlet, while unreacted ozone enters the tail gas generator through the ozone tail gas outlet at the top of the tank for further treatment.

[0032] In the above Examples 1-2, preferably, the selenium-enriched catalyst is a catalyst in which selenium is supported by aluminum or titanium oxide, and the catalyst has a spherical structure.

[0033] In the above embodiments 1-2, the sulfur-containing wastewater entering from the external sulfur-containing wastewater pipeline contains solid impurities. In order to facilitate the discharge of solid impurities, a sewage discharge pipeline 7 is provided at the bottom of both the wastewater buffer tank and the ozone oxidation generator.

[0034] Example 3

[0035] The structure and principle of Example 3 are similar to those of Example 1, with the following differences: For ease of intelligent management, a wastewater flow meter 8 is installed on the pipeline between the wastewater buffer tank and the ozone oxidation reactor to measure the wastewater flow rate; an ozone flow meter 9 is installed on the pipeline between the ozone generator and the ozone oxidation reactor to measure the ozone flow rate. The ozone generation rate is adjusted according to the wastewater influent volume and the sulfide content in the wastewater, resulting in strong process adaptability and a wide treatment range, thereby improving automation and reducing operating costs.

[0036] This invention also provides a heterogeneous ozone advanced oxidation treatment process for sulfur-containing wastewater: adjusting the pH value of the sulfur-containing wastewater to control it between 8.0 and 10.0; then simultaneously introducing the sulfur-containing wastewater and ozone into a tank containing a selenium-enriched catalyst to carry out an advanced oxidation-reduction reaction, based on the sulfur content in the wastewater... 2- The concentration of ozone is adjusted by controlling the concentration of ozone introduced into the wastewater. During this process, the liquid inlet pressure is maintained at 0.1 MPa to 0.2 MPa. A selenium-rich catalyst is used to catalyze the generation of hydroxyl radicals from the ozone, thereby removing sulfur dioxide from the wastewater. 2- Oxidized to SO 2- .

[0037] Under the action of selenium-enriched catalyst, ozone is catalyzed to generate ·OH (hydroxyl radical), which has extremely strong oxidation ability and no selectivity. This promotes the advanced oxidation of sulfides in wastewater with ozone, resulting in more thorough oxidation and higher ozone utilization. The device has strong process adaptability and a wide treatment range. It requires less investment, occupies less space, has a high degree of automation, and has low operating costs.

[0038] In the above embodiments, based on the S of the sulfur-containing wastewater from the gas field 2- The concentration and flow rate of ozone are controlled to maintain the ozone concentration at 25 mg / L to 35 mg / L. In addition to controlling the concentration of introduced ozone, the flow rates of wastewater and ozone entering the tank are controlled using wastewater flow meters and ozone flow meters within the device, thus controlling the concentration of ozone within the reaction tank. 2- And the amount of ozone.

[0039] After extensive testing and verification, the optimal operating conditions for this process are: pH 9.0 for sulfur-containing wastewater, ozone concentration of 30 mg / L, and liquid phase inlet pressure of 0.15 MPa.

[0040] Based on this process, under optimal operating conditions, S 2- The removal rate can reach over 99%, and the treated wastewater contains less sulfur. 2- The purification effect is significant when the concentration is below 0.5 mg / L.

[0041] The above are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent changes made in accordance with the claims of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An integrated treatment device for heterogeneous ozone advanced oxidation of sulfur-containing wastewater, characterized in that: It includes a wastewater buffer tank connected to an external sulfur-containing wastewater pipeline, an ozone oxidation reactor connected to the wastewater buffer tank via a pipeline, and a tail gas processor and an ozone generator connected to the ozone oxidation reactor; the ozone oxidation reactor is connected to an external drainage pipeline and contains a selenium-enriched catalyst; a wastewater lift pump is installed between the pipelines of the ozone oxidation reactor and the wastewater buffer tank. The ozone oxidation reactor includes a tank and a catalyst packing located inside the tank. The catalyst packing is located in the middle of the tank and divides the tank into upper and lower spaces. An ozone exhaust gas outlet connected to the exhaust gas processor is provided at the top of the tank. A liquid drain is provided on the side of the upper space. A sewage drain is provided at the bottom of the tank. A sewage inlet and an ozone inlet are provided on the side wall of the lower space. The ozone inlet adopts a lotus-shaped structure with several upward-facing pores spaced apart on the lotus-shaped structure. The selenium-enriched catalyst uses aluminum and titanium oxides as supports to support selenium, and the catalyst has a spherical structure.

2. The integrated treatment device for heterogeneous ozone advanced oxidation of sulfur-containing wastewater according to claim 1, characterized in that: The connection between the exhaust gas processor and the ozone oxidation reactor is located at the top of the ozone oxidation reactor; the connection between the external drain pipe and the ozone oxidation reactor is located on the upper part of the side wall of the ozone oxidation reactor, and the connection between the external drain pipe and the ozone oxidation reactor is lower than the connection between the exhaust gas processor and the ozone oxidation reactor; the connection between the ozone generator and the ozone oxidation reactor, as well as the connection between the wastewater buffer tank and the ozone oxidation reactor, are all located on the lower part of the side wall of the ozone oxidation reactor.

3. The integrated treatment device for heterogeneous ozone advanced oxidation of sulfur-containing wastewater according to claim 1, characterized in that: Both the wastewater buffer tank and the ozone oxidation reactor are equipped with sewage discharge pipelines at the bottom.

4. The integrated treatment device for heterogeneous ozone advanced oxidation of sulfur-containing wastewater according to claim 1, characterized in that: A wastewater flow meter is installed on the pipeline between the wastewater buffer tank and the ozone oxidation reactor, and an ozone flow meter is installed on the pipeline between the ozone generator and the ozone oxidation reactor.

5. A heterogeneous ozone advanced oxidation treatment process for sulfur-containing wastewater, characterized in that: The integrated treatment device for heterogeneous ozone advanced oxidation of sulfur-containing wastewater as described in any one of claims 1-4 is used to adjust the pH value of the sulfur-containing wastewater to a range of 8.0-10.

0. Subsequently, the sulfur-containing wastewater and ozone are simultaneously introduced into a tank containing a selenium-rich catalyst to carry out an advanced oxidation-reduction reaction. The pH value is determined based on the sulfur content in the wastewater. 2- The concentration of ozone is adjusted by regulating the concentration of the liquid phase inlet; during this process, the liquid phase inlet pressure is maintained at 0.1MPa~0.2MPa.

6. The heterogeneous ozone advanced oxidation treatment process for sulfur-containing wastewater according to claim 5, characterized in that: Based on the sulfur-containing wastewater from the gas field 2- The concentration and flow rate of ozone are controlled to maintain the ozone concentration at 25 mg / L~35 mg / L. In addition to controlling the concentration of introduced ozone, the flow rates of wastewater and ozone entering the tank are controlled using wastewater flow meters and ozone flow meters within the device, thus controlling the concentration of ozone within the reaction tank. 2- And the amount of ozone.

7. The heterogeneous ozone advanced oxidation treatment process for sulfur-containing wastewater according to claim 5, characterized in that: The operating conditions for this process are: pH of sulfur-containing wastewater is 9.0, ozone concentration is 30 mg / L, and liquid phase inlet pressure is 0.15 MPa.

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