Low-carbon zero-emission system for oil exploitation wastewater

Abstract

The utility model discloses a low-carbon zero-discharge system for oil exploitation wastewater, which comprises a wastewater pool, and further comprises a pretreatment unit, a biochemical unit, a membrane concentration unit, an electrocatalytic oxidation unit and an evaporation unit which are connected in sequence, and wastewater is treated along the units in sequence; according to the low-carbon zero-emission system for the oil exploitation wastewater, high-salt and high-concentration wastewater can be converted into biodegradability low-concentration wastewater through the biochemical unit, the evaporation multiple and the evaporation efficiency can be improved through electrocatalytic oxidation, and the evaporation energy consumption is reduced; the problems that ammonia nitrogen and COD in evaporated condensate water exceed the standard, organic matter of an evaporator scales, the evaporation capacity of membrane concentrated liquid is large, and the amount of liquid at the bottom of the kettle is large due to temperature rise caused by organic matter evaporation are solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of wastewater treatment, and in particular relates to a low-carbon zero-emission system for petroleum mining wastewater. Background Art

[0002] Oil is one of the energy sources necessary for the normal operation of today's society. Oil extraction technology is becoming more and more advanced, and the scale of extraction is also increasing. my country's oil extraction generally uses water injection to transport oil, which will produce a lot of wastewater. The wastewater contains a large amount of substances that are difficult to separate and degrade, which increases the viscosity of the wastewater and is not easy to remove by volatilization. Discharging it into the natural world will cause serious pollution. These wastewaters need to be treated before being discharged to promote the green development and sustainable development of the oil extraction industry.

[0003] The defects of the existing low-carbon zero-discharge system for oil production wastewater are:

[0004] 1. Patent document US09254453B2 discloses an economical method for removing hydrogen sulfide from fluids. However, the above document does not use renewable energy, and does not oxidize the organic and inorganic substances in the wastewater that are difficult to treat, which makes the wastewater less volatile, resulting in reduced evaporation efficiency and high energy consumption.

[0005] 2. Patent document KR101272875B1 discloses a zero-discharge wastewater treatment method and system. However, in the above document, in the process of filtering the wastewater, it is difficult to remove organic matter and ammonia nitrogen in the wastewater before evaporation treatment, which easily causes the water quality index after treatment to fail to meet the standard, and multiple treatments are required, which easily leads to technical problems such as increased treatment costs and energy consumption;

[0006] 3. Patent document US08048311B2 discloses a zero-discharge water treatment method and system, but the above document does not recover the reusable iron ions in the wastewater, and when filtering, it is only filtered through a single-layer filter membrane, which easily leads to poor water quality indicators;

[0007] 4. Patent document CN115845460B discloses a petrochemical wastewater discharge system and a discharge method thereof. However, the above document does not address the technical problem of recycling and reusing the produced water or condensed water that meets the standards during the wastewater treatment process. Summary of the invention

[0008] The purpose of the utility model is to design a low-carbon zero-emission system for oil production wastewater, to treat the wastewater used in oil production, to achieve the effect of zero wastewater discharge, and to reduce the waste of resources.

[0009] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0010] A low-carbon zero-emission system for oil production wastewater includes a wastewater pool, characterized in that the system includes a pretreatment unit, a biochemical unit, a membrane concentration unit, an electrocatalytic oxidation unit and an evaporation unit connected in sequence, and the wastewater is treated along the above-mentioned units in sequence. The pretreatment unit includes a flotation system and a high-density sedimentation tank, the biochemical unit includes a biochemical buffer tank and a PBR bioreactor, the membrane concentration unit includes sand filtration, ultrafiltration, low-pressure reverse osmosis, high-pressure reverse osmosis system and a reclaimed water reuse storage tank, the electrocatalytic unit includes an electrocatalytic buffer tank, a main reactor and a sand filter tank, and the evaporation unit includes an evaporator, and the condensed water of the evaporator flows into the reclaimed water reuse storage tank.

[0011] Furthermore, the air flotation system includes an air dissolving pump, an air dissolving water tank, a releaser and a scraping assembly.

[0012] Furthermore, a raw water inlet is provided at the input end of the raw water pool, and the output end of the raw water pool is connected to the input end of the flotation system through a hose. An air dissolving pump is installed on the side of the outer wall of the flotation system, and the air dissolving pump is connected to the air dissolving water tank. A releaser is installed at the outlet of the air dissolving water tank, and the output end of the releaser is installed through the side of the inner wall of the sedimentation water production pool, and a scraper assembly is installed on the top of the sedimentation water production pool.

[0013] Furthermore, the biochemical buffer tank is specifically a secondary sedimentation tank, and the PBR bioreactor converts high-salt and high-concentration organic matter in the wastewater into low-concentration organic matter.

[0014] Furthermore, the sand filter in the membrane concentration unit is prepared by one or more of natural quartz sand, manganese sand and anthracite; the high-pressure reverse osmosis produced water is transported to the low-pressure reverse osmosis through the first reflux pipe; the low-pressure reverse osmosis concentrated water directly enters the high-pressure reverse osmosis, and the low-pressure reverse osmosis produced water enters the front end for reuse; the high-pressure reverse osmosis produced water returns to the low-pressure reverse osmosis, and the concentrated water enters the next unit for oxidation treatment.

[0015] Furthermore, the membrane concentration unit adopts membrane separation technology, which includes ultrafiltration membrane, reverse osmosis membrane and high-pressure reverse osmosis membrane. The ultrafiltration membrane is used to remove suspended matter, colloids, bacteria, and viral macromolecules in water. The reverse osmosis membrane is used to separate the solvent and solute in the solution. The high-pressure reverse osmosis membrane is used to achieve desalination and purification of wastewater. The ultrafiltration membrane and the reverse osmosis membrane are installed in the first membrane separation tank, and the high-pressure reverse osmosis membrane is installed in the second membrane separation tank. The ultrafiltration membrane is installed at the top of the inner wall of the first membrane separation tank, the reverse osmosis membrane is installed at the bottom of the inner wall of the first membrane separation tank, and the high-pressure reverse osmosis membrane is installed in the middle of the inner wall of the second membrane separation tank. The outer wall of the first membrane separation tank is installed with a concentrated water delivery pipe through a water pump, and the other end of the concentrated water delivery pipe is installed through the top of the outer wall of the second membrane separation tank. The bottom of the outer wall of the second membrane separation tank is installed with a produced water delivery pipe through a water pump, and the other end of the produced water delivery pipe is installed through the middle of the outer wall of the first membrane separation tank.

[0016] Furthermore, the electrocatalytic buffer tank is specifically a membrane concentrate water storage tank, a membrane concentrate water storage tank connected to high-pressure reverse osmosis, the outlet water of the main reactor is connected to the water inlet of the sand filter tank, and the sand filter tank is filled with catalyst.

[0017] Furthermore, the wastewater treated by the electrocatalytic oxidation unit directly enters the evaporator for evaporation treatment. The evaporator also includes a water storage tank connected to the electrocatalytic device. The processing capacity of the electrocatalytic oxidation device is equivalent to that of the evaporator.

[0018] The following beneficial effects can be obtained through the above technical solution:

[0019] The utility model low-carbon zero-emission system for petroleum extraction wastewater can convert high-salt and high-concentration wastewater into biodegradable low-concentration wastewater through a biochemical unit. Electrocatalytic oxidation can increase the evaporation multiple and evaporation efficiency, reduce evaporation energy consumption, and solve the problems of excessive ammonia nitrogen and COD in evaporated condensed water, scaling of organic matter in the evaporator, large evaporation of membrane concentrate, and temperature rise caused by evaporating organic matter, resulting in a large amount of liquid at the bottom of the kettle.

[0020] The utility model biochemical unit converts high-salt and high-concentration wastewater that cannot be directly treated by activated sludge into low-concentration wastewater with higher biodegradability. The active groups such as hydroxyl free radicals, superoxide free radicals, H2O2 and hypochlorite generated in the reaction process with the wastewater through the special electrode plates and single flow channels of the electrocatalytic unit oxidize the difficult-to-degrade organic matter and ammonia nitrogen in the water body through the active groups, thereby achieving the effect of oxidative removal of most of the organic matter and ammonia nitrogen. After the electrocatalytic oxidation treatment, the evaporation multiple and evaporation efficiency can be improved, the evaporation energy consumption can be reduced, and the problems of excessive ammonia nitrogen and COD in the evaporated condensed water, the scaling problem of organic matter in the evaporator, the large evaporation amount of the membrane concentrate and the temperature rise caused by the evaporation of organic matter, resulting in a large amount of liquid at the bottom of the kettle, can be solved.

[0021] The manganese sand added in the sand filtration can be used to adsorb the iron ions in the wastewater, and then recycle the iron ions. Through the setting of the first membrane separation tank, the ultrafiltration membrane and the reverse osmosis membrane, the incoming wastewater can be subjected to multiple filtrations. The wastewater separated and concentrated by the low-pressure reverse osmosis membrane is transported to the second membrane separation tank through a water pump and a concentrate delivery pipe, and is further separated and concentrated by a high-pressure reverse osmosis membrane to remove soluble organic matter, inorganic salts and trace harmful substances, thereby reducing the amount of membrane concentrate and increasing the salinity of the membrane concentrate. The wastewater is transported to the first membrane separation tank through a water pump and a produced water delivery pipe for re-filtration to improve the water quality indicators of the produced water.

[0022] Through the setting of the water reuse storage pool, the produced water obtained from the first membrane separation tank and the condensed water obtained from the condenser can be recycled and reused through pipelines, and used in projects that require the use of clean water, such as dilution of wastewater, to achieve the effect of zero wastewater discharge and reduce waste of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a system schematic.

[0024] In the figure:

[0025] In the figure: 1. flotation system; 2. high-density sedimentation tank; 3. biochemical buffer tank; 4. PBR bioreactor; 5. sand filtration; 6. ultrafiltration; 7. low-pressure reverse osmosis; 8. reclaimed water reuse storage tank; 9. high-pressure reverse osmosis; 10. electrocatalytic buffer tank; 11. sand filter tank; 12. main reactor; 13. evaporator. DETAILED DESCRIPTION

[0026] The utility model is further described below in conjunction with the accompanying drawings:

[0027] like Figure 1 As shown, a low-carbon zero-emission system for oil production wastewater includes a wastewater pool, the system includes a pretreatment unit, a biochemical unit, a membrane concentration unit, an electrocatalytic oxidation unit and an evaporation unit connected in sequence, and the wastewater is treated in sequence along the above-mentioned units;

[0028] The pretreatment unit includes an air flotation system 1 and a high-density sedimentation tank 2, which are used to remove suspended matter and a small amount of floating oil from oil production wastewater. The air flotation system includes an air dissolving pump, an air dissolving water tank, a releaser and a scraper assembly. The input end of the raw water tank is provided with a raw water inlet, and the output end of the raw water tank is connected to the input end of the air flotation system through a hose. An air dissolving pump is installed on the side of the outer wall of the air flotation system, and the air dissolving pump is connected to the air dissolving water tank. A releaser is installed at the outlet of the air dissolving water tank. The output end of the releaser is installed on the side of the inner wall of the sedimentation water production tank, and a scraper assembly is installed on the top of the sedimentation water production tank. The pump head of the air dissolving water pump is made of 316L stainless steel, polytetrafluoroethylene or fiberglass; the material of the air dissolving tank is one of 304, 316, and 316L stainless steel.

[0029] The above-mentioned raw water pool is used to store and regulate the amount and quality of raw water, providing a stable water source for subsequent treatment. The flotation system uses micro-nano bubbles to introduce air into the wastewater so that suspended matter attaches to the bubbles and floats to the water surface, thereby separating the suspended matter. The dissolved air pump is used to pressurize and dissolve air or oxygen in water to form high-pressure dissolved air water. The releaser is used to quickly release the gas in the dissolved air water under a specific pressure to form tiny bubbles. The scraper assembly is used to scrape off the floating body floating to the water surface, including suspended matter and grease.

[0030] The biochemical unit includes a biochemical buffer tank 3 and a PBR bioreactor 4. The biochemical buffer tank is specifically a secondary sedimentation tank. The PBR bioreactor converts high-salt and high-concentration organic matter in the wastewater into low-concentration organic matter.

[0031] The membrane concentration unit includes sand filtration 5, ultrafiltration 6, low-pressure reverse osmosis 7, high-pressure reverse osmosis 9 and a reclaimed water reuse storage tank 8, which are used to separate organic matter and concentrate salt from the wastewater after treatment in the biochemical unit. The electrocatalytic unit further oxidizes the membrane concentrate through electrocatalytic oxidation to break the ring and chain, and then enters the evaporation unit for evaporation treatment. The sand filter in the membrane concentration unit is prepared by one or more of natural quartz sand, manganese sand and anthracite; the high-pressure reverse osmosis produced water is transported to the low-pressure reverse osmosis through the first reflux pipeline; the low-pressure reverse osmosis concentrated water directly enters the high-pressure reverse osmosis, and the low-pressure reverse osmosis produced water enters the front-end reuse; the high-pressure reverse osmosis produced water returns to the low-pressure reverse osmosis, and the concentrated water enters the next unit for oxidation treatment; the membrane concentration unit adopts membrane separation technology, and the membrane separation technology includes ultrafiltration membrane, reverse osmosis membrane and high-pressure reverse osmosis membrane, ultrafiltration The membrane is used to remove suspended matter, colloids, bacteria, and virus macromolecules in water. The reverse osmosis membrane is used to separate the solvent and solute in the solution. The high-pressure reverse osmosis membrane is used to achieve desalination and purification of wastewater. The ultrafiltration membrane and the reverse osmosis membrane are installed in the first membrane separation tank, and the high-pressure reverse osmosis membrane is installed in the second membrane separation tank. The ultrafiltration membrane is installed at the top of the inner wall of the first membrane separation tank, the reverse osmosis membrane is installed at the bottom of the inner wall of the first membrane separation tank, and the high-pressure reverse osmosis membrane is installed in the middle of the inner wall of the second membrane separation tank. The outer wall of the first membrane separation tank is installed with a concentrated water delivery pipe through a water pump, and the other end of the concentrated water delivery pipe is installed through the top of the outer wall of the second membrane separation tank. The bottom of the outer wall of the second membrane separation tank is installed with a produced water delivery pipe through a water pump, and the other end of the produced water delivery pipe is installed through the middle of the outer wall of the first membrane separation tank.

[0032] The electrocatalytic unit includes an electrocatalytic buffer tank 10, a main reactor 12 and a sand filter tank 11. The electrocatalytic buffer tank is specifically a membrane concentrate water storage tank, a membrane concentrate water storage tank connected to a high-pressure reverse osmosis, and the outlet water of the main reactor is connected to the water inlet of the sand filter tank, and the sand filter tank is filled with a catalyst. The electrocatalytic treatment technology uses a specific electrochemical reactor to remove pollutants in wastewater. The outlet water of the reactor is connected to the water inlet of the sand filter tank, and the sand filter tank is filled with a catalyst of a certain characteristic. The catalyst is selected from one or more of activated carbon, alumina, and molecular sieves, and the catalyst-loaded metal is one or more of iron, manganese, aluminum, cerium, etc.; the power supply can be selected from one or more of a high-frequency power supply, a DC power supply, a pulse power supply, etc.

[0033] The evaporation unit includes an evaporator 13. The wastewater treated by the electrocatalytic oxidation unit directly enters the evaporator for evaporation treatment. The evaporator also includes a water storage tank connected to the electrocatalytic device. The processing capacity of the electrocatalytic oxidation device is equivalent to that of the evaporator. The condensed water of the evaporator can directly enter the front end for use; the salt mud generated by the evaporator can be directly buried.

[0034] The above are all preferred implementations of the present invention. For ordinary technicians in this technical field, without departing from the principle of the present invention, various equivalent modifications to the present invention belong to the protection scope of the claims attached to this application.

Claims

1. A low-carbon zero-emission system for oil production wastewater, comprising a wastewater pool, characterized in that: The system includes a pretreatment unit, a biochemical unit, a membrane concentration unit, an electrocatalytic oxidation unit and an evaporation unit which are connected in sequence, and wastewater is treated along the above-mentioned units in sequence. The pretreatment unit includes a flotation system and a high-density sedimentation tank, the biochemical unit includes a biochemical buffer tank and a PBR bioreactor, the membrane concentration unit includes sand filtration, ultrafiltration, low-pressure reverse osmosis, high-pressure reverse osmosis system and a reclaimed water reuse storage tank, the electrocatalytic unit includes an electrocatalytic buffer tank, a main reactor and a sand filter tank, and the evaporation unit includes an evaporator, and the condensed water of the evaporator flows into the reclaimed water reuse storage tank.

2. A low-carbon zero-emission system for oil production wastewater according to claim 1, characterized in that: The air flotation system comprises an air-dissolving pump, an air-dissolving water tank, a releaser and a scraping assembly.

3. A low-carbon zero-emission system for oil production wastewater according to claim 2, characterized in that: A raw water inlet is provided at the input end of the raw water pool, and the output end of the raw water pool is connected to the input end of the flotation system through a hose. An air dissolving pump is installed on the side of the outer wall of the flotation system, and the air dissolving pump is connected to the air dissolving water tank. A releaser is installed at the outlet of the air dissolving water tank, and the output end of the releaser is installed through the side of the inner wall of the sedimentation water production pool, and a scraper assembly is installed on the top of the sedimentation water production pool.

4. The low-carbon zero-emission system for oil production wastewater according to claim 1 is characterized by: The biochemical buffer tank is specifically a secondary sedimentation tank, and the PBR bioreactor converts high-salt and high-concentration organic matter in the wastewater into low-concentration organic matter.

5. The low-carbon zero-emission system for oil production wastewater according to claim 1 is characterized by: The sand filter in the membrane concentration unit is made of one or more of natural quartz sand, manganese sand and anthracite; the high-pressure reverse osmosis water is transported to the low-pressure reverse osmosis through the first reflux pipeline; the low-pressure reverse osmosis concentrated water directly enters the high-pressure reverse osmosis, and the low-pressure reverse osmosis water enters the front-end reuse; the high-pressure reverse osmosis water returns to the low-pressure reverse osmosis, and the concentrated water enters the next unit for oxidation treatment.

6. A low-carbon zero-emission system for oil production wastewater according to claim 1, characterized in that: The membrane concentration unit adopts membrane separation technology, which includes ultrafiltration membrane, reverse osmosis membrane and high-pressure reverse osmosis membrane. The ultrafiltration membrane is used to remove suspended matter, colloids, bacteria, and virus macromolecules in water. The reverse osmosis membrane is used to separate the solvent and solute in the solution. The high-pressure reverse osmosis membrane is used to achieve desalination and purification of wastewater. The ultrafiltration membrane and the reverse osmosis membrane are installed in the first membrane separation tank, and the high-pressure reverse osmosis membrane is installed in the second membrane separation tank. The ultrafiltration membrane is installed at the top of the inner wall of the first membrane separation tank, the reverse osmosis membrane is installed at the bottom of the inner wall of the first membrane separation tank, and the high-pressure reverse osmosis membrane is installed in the middle of the inner wall of the second membrane separation tank. The outer wall of the first membrane separation tank is installed with a concentrated water delivery pipe through a water pump, and the other end of the concentrated water delivery pipe is installed through the top of the outer wall of the second membrane separation tank. The bottom of the outer wall of the second membrane separation tank is installed with a produced water delivery pipe through a water pump, and the other end of the produced water delivery pipe is installed through the middle of the outer wall of the first membrane separation tank.

7. The low-carbon zero-emission system for oil production wastewater according to claim 1 is characterized by: The electrocatalytic buffer tank is specifically a membrane concentrate water storage tank, a membrane concentrate water storage tank connected to a high-pressure reverse osmosis, the outlet water of the main reactor is connected to the water inlet of the sand filter tank, and the catalyst is filled in the sand filter tank.

8. The low-carbon zero-emission system for oil production wastewater according to claim 1 is characterized by: After being treated by the electrocatalytic oxidation unit, the wastewater directly enters the evaporator for evaporation treatment. The evaporator also includes a water storage tank connected to the electrocatalytic device. The processing capacity of the electrocatalytic oxidation unit is equivalent to that of the evaporator.

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