A system and process for removing oil and carbon dioxide by negative pressure gas lift from sewage

Abstract

The present invention discloses a system and process for removing oil and carbon dioxide by negative pressure gas lift, which relates to the technical field of sewage treatment, including a deoiling device, a decarbonation device and a carbon dioxide absorption device. The purpose of the present invention is to provide a process and system for removing oil and carbon dioxide by negative pressure gas lift to reduce the oil content and carbon dioxide content in sewage, effectively prevent carbon dioxide from being directly discharged into the environment, and recycle the purified gas lift gas to achieve environmental protection and energy saving, and realize zero carbon dioxide emission. The present invention uses the process of flotation oil removal, negative pressure gas lift decarbonation, and alkaline solution carbon fixation, which has the advantages of small size, low energy consumption, and high treatment efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a system and process for removing oil and carbon dioxide by negative pressure gas lift from sewage. Background Art

[0002] Some blocks of Zhongyuan Oilfield adopt CO2 flooding for oil production, that is, injecting CO2 into the oil layer to increase the recovery rate of crude oil. The CO2 flooding output liquid has high CO2 content and low pH value. The CO2 flooding output liquid is collected and transported to the joint station, enters the three-phase separator for separation, and then mixes with other produced water, resulting in the wastewater in the joint station containing both oil and carbon dioxide, large fluctuations in water quality, and great difficulty in water treatment. The oil content is about 50 mg / L and the pH is about 5.0, which has a great corrosion capacity on equipment and pipelines.

[0003] At present, the main treatment methods are flotation oil removal and acid-base neutralization CO2 removal. The above processes and equipment will cause a large amount of carbon dioxide to be directly discharged into the environment. At the same time, the two unrelated processes will result in a low degree of equipment integration, large size, and high energy consumption, which is also not conducive to energy conservation and environmental protection. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention aims to provide a system and process for removing oil and carbon dioxide by negative pressure gas lift from sewage.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A sewage negative pressure gas lift oil removal and carbon dioxide removal system comprises an oil removal device, a carbon removal device and a carbon dioxide absorption device, wherein the liquid inlet at the lower portion of the oil removal device is connected to a sewage input pipeline, the air inlet at the lower portion of the oil removal device is connected to a gas lift gas inlet pipeline, the liquid outlet at the upper portion of the oil removal device is connected to the liquid inlet at the upper portion of the carbon removal device, an oil discharge port is also provided at the upper portion of the oil removal device, the sewage discharge port at the bottom of the oil removal device is connected to a sewage external discharge pump, the air outlet at the top of the oil removal device is connected to an air suction port of an induced draft fan, the air inlet at the lower portion of the carbon removal device is connected to the gas lift gas inlet pipeline, the sewage discharge port at the bottom of the carbon removal device is connected to a sewage external discharge pump, the sewage external discharge pump is connected to the reflux port at the upper portion of the decarbonization device through a reflux pipe, the air outlet at the top of the decarbonization device is connected to the air suction port of the induced draft fan, the air inlet at the lower portion of the carbon dioxide absorption device is connected to the air outlet of the induced draft fan, A circulating liquid inlet and a circulating liquid outlet are respectively provided at the top and the bottom of the carbon dioxide absorption device, and a circulating pump is provided between the circulating liquid inlet and the circulating liquid outlet. The gas outlet at the top of the carbon dioxide absorption device is connected to the gas stripping gas inlet pipeline through the gas stripping gas reflux pipeline to form a circulation loop. A first aeration component connected to the gas stripping gas inlet pipeline is provided at the lower part of the deoiling device, a second aeration component connected to the gas stripping gas inlet pipeline is provided at the lower part of the decarbonization device, a third aeration component connected to the air inlet is provided at the lower part of the carbon dioxide absorption device, a spray component connected to the liquid inlet is provided at the upper part of the decarbonization device, and the other end of the spray component is connected to the reflux port. A rotating baffle component is provided on one side of the middle part of the spray component, and a plurality of drainage ribs are provided in the spray component. Defoggers are provided at the tops of the deoiling device, the decarbonization device and the carbon dioxide absorption device.

[0007] Furthermore, the stripping gas enters the stripping gas inlet pipe through the blower, and the stripping gas reflux pipe is connected to the stripping gas inlet pipe through the blower. By adjusting the speed of the blower and the induced draft fan, a negative pressure value is formed in the oil removal device and the decarbonization device, and the negative pressure value is maintained at (-15KPa) ~ (-5KPa).

[0008] Furthermore, a pipeline mixer is provided on the sewage input pipeline, the liquid inlet of the pipeline mixer is also connected to the demulsifier filling device, and the liquid outlet of the pipeline mixer is connected to the liquid inlet at the bottom of the oil removal device.

[0009] Furthermore, the first aeration component includes a first aeration pipe connected to the air stripping gas inlet pipe, a plurality of nozzles are arranged on the top of the first aeration pipe, a first spiral blade is rotatably installed in the nozzle, and a plurality of first micropores are opened on the top of the nozzle.

[0010] Furthermore, the second aeration component has the same structure as the third aeration component, and the second aeration component includes a second aeration tube connected to the air stripping gas inlet pipe, and a plurality of diverter columns are provided on the top of the second aeration tube, and a plurality of second micropores are evenly distributed on the side walls of the diverter columns.

[0011] Furthermore, the spray assembly includes a spray main pipe, one end of which is connected to the liquid inlet of the decarburization device, and the other end of which is connected to the reflux port of the decarburization device. Symmetrically arranged spray branches are provided on both sides of the spray main pipe, and there are multiple spray branches, one end of which is connected to the spray main pipe, and the other end is connected to the inner wall of the decarburization device. Several nozzles are provided at the bottom of the spray main pipe and the spray branch pipe, and several cyclones are provided in the spray main pipe and the spray branch pipe. The bottom of the cyclone is connected to the top of the nozzle, and several drainage ribs are provided in the spray main pipe and the spray branch pipe.

[0012] Furthermore, the nozzle includes a connecting pipe connected to the bottom of the cyclone, the bottom of the connecting pipe is connected to the hemispherical head, a threaded groove is provided on the inner wall of the connecting pipe, and a plurality of third microholes are evenly distributed on the connecting pipe and the hemispherical head, and the third microholes gradually change from a horizontal setting to a vertical setting from top to bottom.

[0013] Furthermore, the cyclone comprises an inner hole connected to the top of the nozzle, a plurality of cyclone chambers are evenly distributed on the side wall of the cyclone, the cyclone chambers are connected to the inner hole, and cyclone blades are formed between the cyclone chambers.

[0014] Furthermore, the rotating baffle assembly is located on one side of the connection between the middle part of the spray main pipe and the spray branch pipe, and the rotating baffle assembly includes a connecting rod installed in the spray main pipe, and a first baffle and a second baffle are rotatably provided on the connecting rod, the first baffle and the second baffle are both semicircular, and the first baffle and the second baffle can form a circle, a first torsion spring sleeved on the outer surface of the connecting rod is connected between the first baffle and the connecting rod, and a second torsion spring sleeved on the outer surface of the connecting rod is connected between the second baffle and the connecting rod, a stopper is provided on one side of the connecting rod, and the stopper can contact the side surfaces of the first baffle and the second baffle, and a sealing strip is installed on the arcuate edges of the first baffle and the second baffle.

[0015] A process for removing oil and carbon dioxide by negative pressure gas stripping of sewage, comprising the following steps:

[0016] 1) Oil removal: The oily carbon dioxide-containing sewage (oil content of about 50 mg / L, pH of about 5.0) enters the pipeline mixer through the boosting effect of the pump, and the demulsifier is added into the pipeline mixer through the demulsifier filling device, and enters the oil removal device with an operating pressure of (-15KPa) to (-5KPa) together with the oily carbon dioxide-containing sewage. The stripping gas enters the first aeration pipe of the oil removal device through the blower, and the stripping gas is sprayed from the first micropore of the nozzle to aerate the sewage for demulsification and flotation to remove oil. After demulsification, the oil in the sewage is carried to the upper layer of the sewage with the stripping gas and discharged from the oil discharge port, so that the oil content in the sewage is reduced from 50 mg / L to about 2.0 mg / L. At the same time, the stripping gas carries out part of the carbon dioxide dissolved in the sewage, passes through the demister at the top of the oil removal device, and is discharged from the top of the oil removal device through the negative pressure suction of the induced draft fan;

[0017] 2) Decarbonization: The sewage overflowing from the deoiling device enters the spray main pipe of the decarbonization device with an operating pressure of (-15KPa) ~ (-5KPa), and then enters the spray branch pipe. The sewage enters the nozzle through the cyclone and is sprayed out from the third micropore. The stripping gas enters the second aeration pipe of the decarbonization device from the air inlet at the bottom of the decarbonization device. The stripping gas is discharged from the second micropore on the diverter column. The stripping gas and the sewage are in gas-liquid countercurrent contact on the packing layer to extend the contact time between the stripping gas and the sewage. The stripping gas takes away the carbon dioxide on the surface of the sewage, so that the pH value of the sewage increases from about 5.0 to about 6.5. The sewage is continuously circulated and decarbonated through the reflux pipe to meet the sewage discharge standard. The stripping gas containing carbon dioxide passes through the demister at the top of the decarbonization device and is discharged from the top of the decarbonization device through the negative pressure suction of the induced draft fan;

[0018] 3) Circular absorption: The stripping gas containing carbon dioxide is introduced into the carbon dioxide absorption device through the induced draft fan. There is alkali liquid in the carbon dioxide absorption device. The carbon dioxide is fixed by utilizing the absorption of the stripping gas containing carbon dioxide by the alkali liquid, so that the stripping gas is purified. The purified stripping gas is re-inputted from the stripping gas return pipe into the stripping gas inlet pipe through the blower to form a circulation loop. After the alkali liquid is saturated, it can be exported to the downstream industries of sewage treatment for sewage hardness removal and other utilization, so as to meet the requirements of environmental protection. At the same time, new alkali liquid is added to the carbon dioxide absorption device.

[0019] Compared with the prior art, the present invention provides a system and process for removing oil and carbon dioxide by negative pressure gas stripping of sewage, which has the following beneficial effects:

[0020] 1. The present invention provides an oil removal device and a decarbonization device, and removes oil by flotation in the oil removal device, thereby greatly reducing the oil content in the sewage. By removing carbon dioxide by negative pressure in the decarbonization device, the corrosiveness of acidic sewage to equipment and pipelines is greatly reduced. The gas stripping gas containing carbon dioxide is transported to the carbon dioxide absorption device through an induced draft fan at the top of the oil removal device and the decarbonization device, and carbon dioxide is absorbed and fixed by alkali solution, effectively preventing carbon dioxide from being directly discharged into the environment. The absorbed carbon dioxide can also be further utilized, which is beneficial to environmental protection. The purified gas stripping gas is recycled, which is beneficial to energy saving. The sewage is connected to the reflux port on the upper part of the decarbonization device through a reflux pipe through a sewage external discharge pump, so that the sewage is discharged after it is qualified, thereby protecting the environment. Negative pressure gas stripping is used for the oil removal device and the decarbonization device, breaking the gas-liquid balance of the sewage containing carbon dioxide, improving the removal rate of carbon dioxide, and saving the amount of alkali solution. The present invention realizes zero carbon dioxide emission. The integrated device has the advantages of small size, low energy consumption, high treatment efficiency, etc. through the ability of flotation oil removal, negative pressure decarbonization, and alkali solution carbon fixation.

[0021] 2. The present invention provides a first aeration assembly at the lower part of the oil removal device. Through the pressurization of the blower, the first spiral blade rotates in the nozzle, which accelerates the flow of gas, increases the number of bubbles, and achieves uniform contact with sewage, thereby improving the mixing effect of sewage and demulsifier. The air stripping gas is attached to the oil droplets in the form of highly dispersed tiny bubbles, forming a state with a density far less than that of water, so that it floats to the surface and gathers, realizing oil-water separation, and can remove most of the floating oil, thereby improving the efficiency of oil-water separation. In addition, the bubbles can also carry more carbon dioxide, thereby improving the removal rate of carbon dioxide;

[0022] 3. The present invention provides a second aeration assembly at the lower part of the decarbonization device, and the stripping gas enters the second aeration pipe, and then enters the diverter column, and is discharged from the second micropores, so that the stripping gas is evenly distributed, and slowly rises on the packing layer, and contacts with the sewage in countercurrent, thereby extending the contact time between the stripping gas and the sewage and improving the removal rate of carbon dioxide;

[0023] 4. The present invention provides a third aeration assembly at the lower part of the carbon dioxide absorption device, and the stripping gas containing carbon dioxide enters the second aeration pipe, and then enters the diverter column, and is discharged from the second micropores, so that the stripping gas containing carbon dioxide is evenly distributed and rises slowly, which prolongs the contact time between the stripping gas containing carbon dioxide and the alkali solution, improves the purification effect of the stripping gas, and removes most of the CO2;

[0024] 5. The present invention provides a spray assembly at the upper part of the decarbonization device, and the sewage overflowing from the oil removal device enters the spray main pipe and the spray branch pipe. Since the sewage is overflowing and lacks pressure, when the sewage enters the inner hole through the cooperation of the drainage ribs and the cyclone cavity on the cyclone, a vortex will be formed, the flow rate will be increased, and the water pressure will be increased. When the sewage passes through the threaded groove of the connecting pipe, the rotation speed will be further increased, and the vortex sewage will be discharged from the third micropore. Since the third micropore is gradually changed from horizontal to vertical from top to bottom, the sewage is sprayed all around and evenly distributed, so that the sewage can be more quickly and evenly distributed on the packing layer and contact with the upward-flowing gas stripping gas, thereby improving the removal rate of carbon dioxide;

[0025] 6. The present invention provides a rotating baffle assembly on one side of the connection between the middle part of the spray main pipe and the spray branch pipe. When the overflowing sewage flows through the first baffle and the second baffle through the spray main pipe, the overflowing sewage will drive the first baffle and the second baffle to rotate, so that the overflowing sewage flows to the other end of the spray main pipe, and then enters the spray branch pipe at the other end, so that the overflowing sewage can flow out of the nozzles on the spray main pipe and all the spray branches; when the sewage discharge pump re-inputs the sewage into the spray main pipe through the return pipe, the water pressure of the return sewage is greater than the water pressure of the overflowing sewage. Therefore, the return sewage drives the first baffle and the second baffle to rotate in the opposite direction, and the first torsion spring and the second torsion spring are connected. Under the action of the spring, the first baffle and the second baffle can quickly rotate in the opposite direction and return to the initial position. Since the block blocks the first baffle and the second baffle, they stop rotating when they return to the initial position. The sealing strips of the first baffle and the second baffle form a tight seal on the spray main pipe, and the spray main pipe is divided into two parts, one part flows through the overflow sewage, and the other part flows through the return sewage, so that when the return sewage flows back and sprays, it will not collide with the overflow sewage, and will not cause turbulence to the overflow sewage, affecting the spraying of the overflow sewage, and avoiding the excessive water pressure of the return sewage from flowing back into the oil removal device through the liquid inlet of the decarbonization device, affecting the operation of the entire device.

[0026] 7. The present invention provides a plurality of drainage ribs in the spray main pipe and the spray branch pipe, and the longitudinal cross-sectional area at both ends of the drainage ribs is smaller than the longitudinal cross-sectional area in the middle of the drainage ribs, so as to enhance the drainage and pressurization speed-up effect. During the flow of overflow sewage in the spray main pipe and the spray branch pipe, the overflow sewage will first flow from one end of the drainage rib to the middle of the drainage rib, and then flow from the middle of the drainage rib to the other end of the drainage rib. In this process, the drainage rib first divides the overflow sewage into two parts, and then brings the two parts of overflow sewage together to increase the flow rate of the overflow sewage, so that the overflow sewage reaches the first baffle and the second baffle. When the baffle is opened, it can overcome the action force of the first torsion spring and the second torsion spring, drive the first baffle and the second baffle to rotate, which can increase the flow rate of the overflow sewage in the spray main pipe and the spray branch pipe, and make the overflow sewage have a certain flow rate before entering the cyclone chamber for acceleration. The flow rate will be further increased by passing through the cyclone chamber, and the spraying of the overflow sewage will be accelerated, thereby improving the treatment efficiency of the decarbonization device; when the sewage external discharge pump re-inputs the sewage into the spray main pipe through the return pipe, the return sewage will be further increased under the action of the drainage ribs. The flow rate will be accelerated and the spraying of the return sewage will be improved, thereby improving the treatment efficiency of the decarbonization device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0028] Figure 2 It is a schematic diagram of the front cross-sectional structure of the oil removal device of the present invention;

[0029] Figure 3 It is a schematic diagram of the front cross-sectional structure of the decarburization device of the present invention;

[0030] Figure 4 is a schematic diagram of a front cross-sectional structure of a carbon dioxide absorption device;

[0031] Figure 5 yes Figure 2 A schematic diagram of the enlarged structure at A in the middle;

[0032] Figure 6 yes Figure 3 A schematic diagram of the enlarged structure at B in the middle;

[0033] Figure 7 yes Figure 3 Schematic diagram of the enlarged structure at C in the middle;

[0034] Figure 8 It is a schematic diagram of the top cross-sectional structure of the nozzle body of the present invention;

[0035] Fig. 9 1 is a schematic diagram of a top cross-sectional structure of a cyclone of the present invention;

[0036] Fig.101 is a schematic diagram of the structure of the spray assembly of the present invention when viewed from above;

[0037] Fig.11 yes Fig.10 Schematic diagram of the enlarged structure at D in the middle;

[0038] Fig.12 It is a right side cross-sectional structural schematic diagram of the rotary baffle assembly of the present invention;

[0039] Fig.13 yes Fig.12 Schematic diagram of the enlarged structure at E in the middle;

[0040] Fig.14 It is a front view cross-sectional structural schematic diagram of the rotary baffle assembly of the present invention.

[0041] Markings in the figure: 1. oil removal device; 2. decarbonization device; 3. carbon dioxide absorption device; 4. pipeline mixer; 5. blower; 6. induced draft fan; 7. sewage effluent pump; 8. circulation pump; 9. demulsifier filling device; 10. liquid flow meter; 11. gas flow meter; 12. first aeration component; 121. first aeration pipe; 122. nozzle; 123. first spiral blade; 124. first micropore; 13. second aeration component; 131. second aeration pipe; 132. diverter column; 133. second micropore; 14. third aeration component; 1 5. demister; 16. spray assembly; 161. spray main pipe; 162. spray branch pipe; 163. nozzle; 1631. connecting pipe; 1632. hemispherical head; 1633. threaded groove; 1634. third micropore; 164. cyclone; 1641. inner hole; 1642. swirl chamber; 1643. swirl blade; 17. rotating baffle assembly; 171. connecting rod; 172. first baffle; 173. second baffle; 174. first torsion spring; 175. second torsion spring; 176. block; 177. sealing strip; 18. drainage rib. DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0043] The standard parts used in the present invention can all be purchased from the market, and special-shaped parts can be customized according to the description in the specification and the drawings. The specific connection methods of each part adopt conventional means such as mature bolts, rivets, welding, etc. in the prior art. Machinery, parts and equipment all adopt conventional models in the prior art, and the circuit connection adopts the conventional connection method in the prior art, which will not be described in detail here.

[0044] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "longitudinal", "horizontal", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0045] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] The embodiment of the present invention provides a wastewater negative pressure gas lift oil removal and carbon dioxide removal system, referring to Figures 1 to 4 , including an oil removal device 1, a decarbonization device 2 and a carbon dioxide absorption device 3;

[0047] The liquid inlet at the bottom of the oil removal device 1 is connected to the sewage input pipeline, the air inlet at the bottom of the oil removal device 1 is connected to the air stripping gas inlet pipeline, the liquid outlet at the top of the oil removal device 1 is connected to the liquid inlet at the top of the decarbonization device 2, and the top of the oil removal device 1 is also provided with an oil discharge port, the sewage discharge port at the bottom of the oil removal device 1 is connected to the sewage external discharge pump 7, and the air outlet at the top of the oil removal device 1 is connected to the air suction port of the induced draft fan 6;

[0048] The air inlet at the bottom of the decarbonization device 2 is connected to the air stripping air inlet pipeline, the sewage outlet at the bottom of the decarbonization device 2 is connected to the sewage effluent pump 7, and the sewage effluent pump 7 is connected to the reflux port at the top of the decarbonization device 2 through a reflux pipeline. By setting the reflux pipeline, the sewage at the bottom of the decarbonization device 2 is fully refluxed and mixed until the sewage is qualified before it can be discharged, which is convenient for the lower level (such as a sewage treatment plant) to treat the sewage and reduce pollution. The air outlet at the top of the decarbonization device 2 is connected to the air suction port of the induced draft fan 6;

[0049] Preferably, an oil drain valve is provided at the oil outlet of the oil removal device 1, a sewage overflow valve is provided at the liquid outlet of the oil removal device 1, the liquid inlet of the decarbonization device 2 is 150 mm higher than the liquid outlet of the oil removal device 1, and the oil drain port of the oil removal device 1 is 100 mm higher than the liquid inlet of the decarbonization device 2, so that the floating oil is always stored in the 150 mm space above the liquid outlet of the oil removal device 1. When the oil needs to be drained, the oil drain valve is opened and the sewage overflow valve is closed, so that the overall liquid level in the oil removal device 1 rises to the oil drain port, and the oil is continuously discharged until the oil drain valve is closed when there is water, and then the sewage overflow valve is opened to resume the process steps; an overflow weir plate is provided on the upper part of the oil removal device 1, so that the sewage can flow out evenly.

[0050] Preferably, a pH probe is installed between the liquid outlet at the top of the oil removal device 1 and the liquid inlet at the top of the decarbonization device 2 to perform online real-time detection of the pH value of the wastewater flowing from the oil removal device 1 into the decarbonization device 2;

[0051] A PH probe is provided between the sewage outlet at the bottom of the decarbonization device 2 and the sewage discharge pump 7, which can detect the PH value of the sewage online in real time, monitor the effluent quality, and check whether the sewage meets the discharge standard through the PH value data.

[0052] By comparing the value of the PH probe between the liquid outlet at the top of the oil removal device 1 and the liquid inlet at the top of the decarbonization device 2 with the value of the PH probe between the sewage outlet at the bottom of the decarbonization device 2 and the sewage discharge pump 7, the difference is calculated and the decarbonization capacity of the decarbonization device 2 can be evaluated.

[0053] Preferably, the stripping gas is nitrogen.

[0054] Preferably, liquid level meters are also provided at the air inlet and the pH probe of the decarbonization device 2 to accurately measure and monitor in real time the volume, liquid height and weight of the bottom liquid in the decarbonization device 2 .

[0055] The air inlet at the lower part of the carbon dioxide absorption device 3 is connected to the air outlet of the induced draft fan 6, and the upper part and the bottom part of the carbon dioxide absorption device 3 are respectively provided with a circulating liquid inlet and a circulating liquid outlet, and a circulating pump 8 is provided between the circulating liquid inlet and the circulating liquid outlet. The air outlet at the top of the carbon dioxide absorption device 3 is connected to the gas stripping gas inlet pipeline through the gas stripping gas reflux pipeline to form a circulation loop.

[0056] Preferably, a liquid level meter is also provided below the air inlet of the carbon dioxide absorption device 3 and at the bottom of the packing layer to accurately measure and monitor in real time the volume, liquid height and weight of the liquid in the carbon dioxide absorption device 3; the air inlet at the bottom of the carbon dioxide absorption device 3 is connected to the air outlet of the induced draft fan 6 through an induced draft duct.

[0057] Preferably, both the lift gas inlet pipe and the induced air pipe are provided with a one-way valve.

[0058] Reference Figures 2 to 4 The lower part of the oil removal device 1 is provided with a first aeration assembly 12 connected to the stripping gas inlet pipeline, the lower part of the decarbonization device 2 is provided with a second aeration assembly 13 connected to the stripping gas inlet pipeline, and the lower part of the carbon dioxide absorption device 3 is provided with a third aeration assembly 14 connected to the air inlet;

[0059] Specifically, by providing the first aeration component 12, the mixing effect on the sewage and the demulsifier is improved, thereby improving the efficiency of oil-water separation; by providing the second aeration component 13, the stripping gas is evenly distributed, and is slowly rising on the packing layer, and countercurrently contacts the sewage, thereby prolonging the contact time between the stripping gas and the sewage, and improving the removal rate of carbon dioxide; by providing the third aeration component 14, the stripping gas containing carbon dioxide is evenly distributed and slowly rising, thereby prolonging the contact time between the stripping gas containing carbon dioxide and the alkali solution, and improving the purification effect of the stripping gas.

[0060] Reference Figure 2 and Fig.10 A spray assembly 16 connected to the liquid inlet is provided at the upper part of the decarburization device 2, the other end of the spray assembly 16 is connected to the reflux port, a rotating baffle assembly 17 is provided on one side of the middle part of the spray assembly 16, and a plurality of drainage ribs 18 are provided in the spray assembly 16;

[0061] Specifically, by setting up a spray assembly 16 to spray the sewage, the contact time between the gas lift gas and the sewage is prolonged, and the removal rate of carbon dioxide is improved; by setting up a rotating baffle assembly 17, it is prevented that the backflow sewage will collide with the overflow sewage and cause turbulence to the overflow sewage, thereby affecting the spraying of the overflow sewage, and it is prevented that the backflow sewage has too high a water pressure and flows back into the oil removal device through the liquid inlet of the decarbonization device, thereby affecting the operation of the entire device; by setting up a drainage rib 18, the drainage and pressurization speed-up effects are enhanced, the sewage flow rate is increased, the spraying of the sewage is accelerated, and the treatment efficiency of the decarbonization device 2 is improved.

[0062] The tops of the oil removal device 1 , the carbon removal device 2 and the carbon dioxide absorption device 3 are all provided with demisters 15 .

[0063] Specifically, refer to Figures 2 to 4 The demister 15 is a flat-plate demister currently available on the market. When the gas passes through the demister 15, the mist droplets entrained in the gas will be thrown onto the blades of the demister 15, thereby achieving gas-liquid separation, preventing sewage from entering the carbon dioxide absorption device 3 through the induced draft fan 6 to cause pollution, and preventing alkali liquid from entering the oil removal device 1 and the decarbonization device 2 through the gas stripping gas reflux pipeline to cause pollution.

[0064] Reference Figure 1In this embodiment, the stripping gas enters the stripping gas inlet pipe through the blower 5, and the stripping gas reflux pipe is connected to the stripping gas inlet pipe through the blower 5. By adjusting the speed of the blower 5 and the induced draft fan 6, a negative pressure value is formed in the oil removal device 1 and the decarbonization device 2, and the negative pressure value is maintained at (-15KPa) ~ (-5KPa).

[0065] Preferably, the air volume of the blower 5 can be adjusted according to the value of the PH probe between the sewage outlet at the bottom of the decarbonization device 2 and the sewage discharge pump 7 by adjusting the valve between the air inlet at the bottom of the decarbonization device 2 and the blower 5. The larger the air volume of the blower 5, the greater the blowing efficiency, and the stronger the decarbonization capacity of the decarbonization device 2; the smaller the air volume of the blower 5, the lower the blowing efficiency, and the weaker the decarbonization capacity of the decarbonization device 2.

[0066] By controlling the speed of the motor, the speed of the blower 5 and the induced draft fan 6 are different, so that a negative pressure value is formed in the oil removal device 1 and the decarbonization device 2. The carbon dioxide in the sewage is removed in time through this negative pressure value, and the balance of carbon dioxide in the gas-liquid two-phase in the sewage is destroyed, so that carbon dioxide is separated from the sewage gas-liquid, and the decarbonation efficiency is improved. Because carbon dioxide exists in water mainly in the form of carbonic acid, bicarbonate, and carbonate, and carbon dioxide gas is an acidic gas. When the content is high, the water is acidic. Through negative pressure gas stripping, the solubility of carbon dioxide in sewage will be destroyed, so that more carbon dioxide is separated, and the remaining content reaches a balance at about PH 6.5, mainly existing in bicarbonate, which is an allowable value. When there is too much carbon dioxide, the sewage becomes acidic, there are many hydrogen ions, and there are a large number of chloride ions in the sewage, which is highly corrosive to equipment and pipelines. After a part of carbon dioxide is removed, the pH rises to about 6.5, which is close to neutral, and the hydrogen ions are relatively much smaller, so the corrosion to equipment and pipelines is small.

[0067] Reference Figure 1 In this embodiment, a pipeline mixer 4 is provided on the sewage input pipeline, the liquid inlet of the pipeline mixer 4 is also connected to the demulsifier filling device 9, and the liquid outlet of the pipeline mixer 4 is connected to the liquid inlet at the bottom of the oil removal device 1.

[0068] Among them, a liquid flow meter 10 is provided on the sewage input pipeline between the liquid outlet of the pipeline mixer 4 and the liquid inlet at the lower part of the oil removal device 1, for real-time online detection and observation of the sewage treatment volume; a gas flow meter 11 is provided on the gas lift gas inlet pipeline connected to the air inlet at the lower part of the decarbonization device 2, for real-time online detection and observation of the gas lift gas treatment volume; the liquid flow meter 10 and the gas flow meter 11 can be used to count the gas-liquid ratio in detail, and analyze and evaluate the effect of negative pressure removal of carbon dioxide by the gas lift gas.

[0069] Among them, refer to Figure 1In this embodiment, the oil removal device 1 is an oil removal tower, the decarbonization device 2 is a decarbonization tower, and the carbon dioxide absorption device 3 is a carbon dioxide absorption tower.

[0070] Reference Figure 1 , Figure 3 and Figure 4 In this embodiment, both the decarbonization device 2 and the carbon dioxide absorption device 3 are provided with a packing layer.

[0071] The stripping gas enters the decarbonization device 2, and the stripping gas contacts the sewage in countercurrent. The contact area between the sewage and the stripping gas is increased through the packing layer, thereby improving the CO2 removal rate, accelerating the reaction rate, and reducing the equipment volume.

[0072] Preferably, the reflux port on the upper part of the decarbonization device 2 is arranged above the packing layer, and the return sewage is decarbonized again through the packing, and can only be discharged after the sewage is qualified.

[0073] The stripping gas containing carbon dioxide enters the carbon dioxide absorption device 3, passes through the packing layer, and fully contacts with the circulating alkali solution from bottom to top, so that the residual CO2 is completely removed, and the stripping gas is purified and recycled.

[0074] The packing layer adopts ceramic ball ring packing, which is an open-hole ring-shaped packing with equal height and diameter developed on the basis of ceramic Raschig ring. Each layer of window holes has 5 tongues, and each tongue blade bends inwardly to point to the center of the ring. The positions of the upper and lower layers of window holes are opposite and staggered. Generally, the open hole area accounts for about 30% of the total area of ​​the ring wall, so that the gas and liquid in the tower can pass freely through the window holes, which improves the gas-liquid distribution, makes full use of the inner surface of the ring, and increases the mass transfer efficiency.

[0075] Reference Figure 2 and Figure 5 In this embodiment, the first aeration component 12 includes a first aeration tube 121 connected to the air stripping gas inlet pipeline, a plurality of nozzles 122 are provided on the top of the first aeration tube 121, a first spiral blade 123 is rotatably installed in the nozzle 122, and a plurality of first micropores 124 are opened on the top of the nozzle 122.

[0076] Specifically, the first spiral blade 123 is vertically arranged to facilitate the airflow to drive the first spiral blade 123 to rotate; the first microhole 124 is vertically arranged.

[0077] Through the pressurization of the blower 5, the first spiral blade 123 rotates in the nozzle 122, which accelerates the flow of gas, increases the number of bubbles, achieves uniform contact with sewage, and improves the mixing effect on sewage and demulsifier. The air stripping gas is attached to the oil droplets in the form of highly dispersed tiny bubbles, forming a state with a density far less than that of water, so that it floats to the surface and gathers, realizing oil-water separation, and can remove most of the floating oil, thereby improving the efficiency of oil-water separation. In addition, the bubbles can also carry more carbon dioxide, thereby improving the removal rate of carbon dioxide.

[0078] Reference Figure 3 , Figure 4 and Figure 6 In this embodiment, the second aeration component 13 has the same structure as the third aeration component 14. The second aeration component 13 includes a second aeration tube 131 connected to the gas stripping gas inlet pipe. A plurality of diverter columns 132 are provided on the top of the second aeration tube 131. A plurality of second micropores 133 are evenly distributed on the side walls of the diverter columns 132.

[0079] Specifically, the second microholes 133 are arranged horizontally.

[0080] By providing a second aeration assembly 13 at the lower part of the decarbonization device 2, the stripping gas enters the second aeration pipe 131, then enters the diverter column 132, and is discharged from the second micropores 133, so that the stripping gas is evenly distributed and slowly rises on the packing layer, and contacts with the sewage in countercurrent, thereby extending the contact time between the stripping gas and the sewage and improving the removal rate of carbon dioxide;

[0081] By providing a third aeration assembly 14 at the lower part of the carbon dioxide absorption device 3, the stripping gas containing carbon dioxide enters the second aeration pipe 131, then enters the diverter column 132, and is discharged from the second micropores 133, so that the stripping gas containing carbon dioxide is evenly distributed and rises slowly, thereby extending the contact time between the stripping gas containing carbon dioxide and the alkali solution, improving the purification effect of the stripping gas, and removing most of the CO2.

[0082] Reference Figure 1 In this embodiment, pressure gauges and pressure transmitters are provided on one side of the gas outlets at the tops of the oil removal device 1 , the decarbonization device 2 and the carbon dioxide absorption device 3 .

[0083] The pressure parameters of each device's operating conditions are displayed through a pressure gauge, and online observation and real-time control of pressure are achieved through a pressure transmitter.

[0084] Reference Figures 7 to 11In the present embodiment, the spray assembly 16 comprises a spray main pipe 161, one end of which is connected to the liquid inlet of the decarburization device 2, and the other end of which is connected to the reflux port of the decarburization device 2. Symmetrically arranged spray branches 162 are arranged on both sides of the spray main pipe 161, and there are multiple spray branches 162, one end of which is connected to the spray main pipe 161, and the other end is connected to the inner wall of the decarburization device 2. Several nozzles 163 are arranged at the bottom of the spray main pipe 161 and the spray branch pipe 162, and several cyclones 164 are arranged in the spray main pipe 161 and the spray branch pipe 162, and the bottom of the cyclone 164 is connected to the top of the nozzle 163, and several drainage ribs 18 are arranged in the spray main pipe 161 and the spray branch pipe 162.

[0085] Reference Fig.10 Specifically, the nozzles 163 are evenly arranged along concentric circles concentric with the inner wall of the decarbonization device 2, and each concentric circle is evenly arranged along the radial direction of the decarbonization device 2, and the nozzles 163 are evenly distributed to achieve the best spraying effect; by setting the cyclone 164, the sewage forms a vortex, the flow rate is increased, and the water pressure is increased; preferably, the longitudinal cross-sectional area at both ends of the drainage rib 18 is smaller than the longitudinal cross-sectional area in the middle of the drainage rib 18, and the drainage rib 18 is extended along the axial direction of the spray main pipe 161 and the spray branch pipe 162 to enhance the drainage and pressurization speed-up effect, increase the sewage flow rate, accelerate the spraying of sewage, and improve the treatment efficiency of the decarbonization device 2; the installation position of the drainage rib 18 can be adjusted according to actual conditions.

[0086] Reference Figure 7 and Figure 8 In this embodiment, the nozzle 163 includes a connecting pipe 1631 connected to the bottom of the cyclone 164, the bottom of the connecting pipe 1631 is connected to the hemispherical head 1632, and a threaded groove 1633 is provided on the inner wall of the connecting pipe 1631, which will further increase the rotation speed and improve the water pressure. A plurality of third micropores 1634 are evenly distributed on the connecting pipe 1631 and the hemispherical head 1632, and the third micropores 1634 are gradually changed from horizontal setting to vertical setting from top to bottom, so that the sewage is sprayed all around and evenly distributed, so that the sewage can be evenly distributed on the packing layer faster and contact with the upward-flowing gas stripping gas, thereby improving the removal rate of carbon dioxide.

[0087] Specifically, the connecting pipe 1631 and the hemispherical head 1632 are designed in an integrated manner; the thread direction of the thread groove 1633 is consistent with the swirl direction of the swirl chamber 1642, which is convenient for accelerating the sewage;

[0088] Preferably, the third micropore 1634 is also arranged in an arc shape, and the direction of the arc is consistent with the thread direction of the thread groove 1633, so that the sewage has a spiral motion after passing through the third micropore 1634, and is easier to disperse.

[0089] Reference Figure 7 and Fig. 9 In this embodiment, the cyclone 164 includes an inner hole 1641 connected to the top of the nozzle 163, and a plurality of swirl chambers 1642 are evenly distributed on the side wall of the cyclone 164. The swirl chambers 1642 are connected to the inner hole 1641, and swirl blades 1643 are formed between the swirl chambers 1642.

[0090] Specifically, the inner hole 1641 is opened at the bottom of the cyclone 164; a cyclone chamber 1642 is formed between two cyclone blades 1643, and the cyclone blades 1643 are evenly distributed along the circumferential direction of the cyclone 164. The cyclone blades 1643 are arc-shaped, and the number of the cyclone blades 1643 is 2-10. In the present embodiment, the number of the cyclone blades 1643 is 4.

[0091] Reference Figures 10 to 14 In this embodiment, the rotating baffle assembly 17 is located at one side of the connection between the middle part of the spray main pipe 161 and the spray branch pipe 162. The rotating baffle assembly 17 includes a connecting rod 171 installed in the spray main pipe 161. A first baffle 172 and a second baffle 173 are rotatably provided on the connecting rod 171. The first baffle 172 and the second baffle 173 are both semicircular, and the first baffle 172 and the second baffle 173 can form a circle. A first torsion spring 174 sleeved on the outer surface of the connecting rod 171 is connected between the first baffle 172 and the connecting rod 171, and a second torsion spring 175 sleeved on the outer surface of the connecting rod 171 is connected between the second baffle 173 and the connecting rod 171. A stopper 176 is provided on one side of the connecting rod 171, and the stopper 176 can contact the side surfaces of the first baffle 172 and the second baffle 173. A sealing strip 177 is installed on the arcuate edges of the first baffle 172 and the second baffle 173.

[0092] Specifically, the block 176 is located on the side of the connecting rod 171 away from the return port; the block 176 is arranged parallel to the connecting rod 171, and both ends of the block 176 are connected to the inner wall of the spray pipe 161; a sealing layer is provided on the side of the block 176 that contacts the first baffle 172 and the second baffle 173 to prevent the backflow sewage from flowing through the narrow gap at the connection between the first baffle 172 and the second baffle 173, causing disturbance to the overflow sewage;

[0093] Reference Fig.14 Preferably, the block 176 is triangular in shape. When the overflow sewage passes through the block 176 and drives the first baffle 172 and the second baffle 173 to rotate, the block 176 can divide the overflow sewage into two streams, and try not to affect the flow rate and water pressure of the overflow sewage; initially, the first baffle 172 and the second baffle 173 form a circle, dividing the spray main pipe 161 into two parts;

[0094] When the overflowing sewage flows through the first baffle 172 and the second baffle 173 through the spray main pipe 161, the overflowing sewage will drive the first baffle 172 and the second baffle 173 to rotate, so that the overflowing sewage flows to the other end of the spray main pipe 161, and then enters the spray branch pipe 162 at the other end, so that the overflowing sewage can flow out of the spray main pipe 161 and the nozzles 163 on all the spray branches 162; when the sewage effluent pump 7 re-inputs the sewage into the spray main pipe 161 through the return pipe, the water pressure of the return sewage is greater than the water pressure of the overflowing sewage. Therefore, the return sewage drives the first baffle 172 and the second baffle 173 to rotate in the opposite direction, and under the action of the first torsion spring 174 and the second torsion spring 175, the first baffle 1 72 and the second baffle 173 can quickly rotate in the opposite direction and return to the initial position. Since the block 176 blocks the first baffle 172 and the second baffle 173, the first baffle 172 and the second baffle 173 will no longer rotate when they return to the initial position. The sealing strip 177 of the first baffle 172 and the second baffle 173 forms a tight seal on the spray main pipe 161, and the spray main pipe 161 is divided into two parts, one part flows through the overflow sewage, and the other part flows through the return sewage, so that when the return sewage flows back and sprays, it will not collide with the overflow sewage, and will not cause turbulence to the overflow sewage, affecting the spraying of the overflow sewage, and avoiding the excessive water pressure of the return sewage from flowing back to the oil removal device 1 through the liquid inlet of the decarbonization device 2, affecting the operation of the entire device.

[0095] A process for removing oil and carbon dioxide by negative pressure gas stripping of sewage, comprising the following steps:

[0096] 1) Oil removal: The oily carbon dioxide-containing sewage (oil content of about 50 mg / L, pH of about 5.0) enters the pipeline mixer 4 through the boosting effect of the pump, and the demulsifier is added into the pipeline mixer 4 through the demulsifier filling device 9, and enters the oil removal device 1 with an operating pressure of (-15 KPa) to (-5 KPa) together with the oily carbon dioxide-containing sewage. The stripping gas enters the first aeration pipe 121 of the oil removal device 1 through the blower 5, and the stripping gas is sprayed from the first micropore 124 of the nozzle 122 to aerate and demulsify the sewage, and the oil is removed by flotation. After demulsification, the oil in the sewage is carried to the upper layer of the sewage with the stripping gas and discharged from the oil discharge port, so that the oil content in the sewage is reduced from 50 mg / L to about 2.0 mg / L. At the same time, the stripping gas carries out part of the carbon dioxide dissolved in the sewage, passes through the demister 15 at the top of the oil removal device 1, and is discharged from the top of the oil removal device 1 through the negative pressure suction of the induced draft fan 6;

[0097] 2) Decarbonization: The sewage overflowing from the deoiling device 1 enters the spray main pipe 161 of the decarbonization device 2 with an operating pressure of (-15KPa) to (-5KPa), and then enters the spray branch pipe 162. The sewage enters the nozzle 163 through the cyclone 164 and is sprayed out from the third micropore 1634. The stripping gas enters the second aeration pipe 131 of the decarbonization device 2 from the air inlet at the bottom of the decarbonization device 2. The stripping gas is discharged from the second micropore 133 on the diverter column 132. The stripping gas and the sewage are in gas-liquid countercurrent contact on the packing layer to extend the contact time between the stripping gas and the sewage. The stripping gas takes away the carbon dioxide on the surface of the sewage, so that the pH value of the sewage increases from about 5.0 to about 6.5. The sewage is continuously circulated and decarbonated through the reflux pipe to meet the sewage discharge standard. The stripping gas containing carbon dioxide passes through the demister 15 at the top of the decarbonization device 2 and is discharged from the top of the decarbonization device 2 through the negative pressure suction of the induced draft fan 6;

[0098] 3) Circular absorption: the stripping gas containing carbon dioxide is introduced into the carbon dioxide absorption device 3 through the induced draft fan 6. There is alkali liquid in the carbon dioxide absorption device 3. The carbon dioxide is fixed by utilizing the absorption of the alkali liquid to the stripping gas containing carbon dioxide, so that the stripping gas is purified. The purified stripping gas is re-inputted from the stripping gas return pipe into the stripping gas inlet pipe through the blower 5 to form a circulation loop. After the alkali liquid is saturated, it can be exported to the downstream industry of sewage treatment for sewage hardness removal and other utilization, so as to meet the requirements of environmental protection. At the same time, new alkali liquid is added to the carbon dioxide absorption device 3.

[0099] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0100] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field can still combine, add, delete or make other adjustments to the features in the various embodiments of the present invention according to the circumstances without conflict, without making creative work, so as to obtain different other technical solutions that do not deviate from the concept of the present invention in essence, and these technical solutions also belong to the scope of protection of the present invention.

Claims

1. A wastewater negative pressure gas lift oil removal and carbon dioxide removal system, characterized in that: It comprises an oil removal device (1), a carbon removal device (2) and a carbon dioxide absorption device (3); The liquid inlet at the bottom of the oil removal device (1) is connected to the sewage input pipeline, the air inlet at the bottom of the oil removal device (1) is connected to the gas stripping gas inlet pipeline, the liquid outlet at the top of the oil removal device (1) is connected to the liquid inlet at the top of the decarbonization device (2), the oil removal device (1) is also provided with an oil discharge port at the top, the sewage discharge port at the bottom of the oil removal device (1) is connected to the sewage external discharge pump (7), and the air outlet at the top of the oil removal device (1) is connected to the air suction port of the induced draft fan (6); The air inlet at the bottom of the decarbonization device (2) is connected to the air stripping air inlet pipeline, the sewage outlet at the bottom of the decarbonization device (2) is connected to the sewage effluent pump (7), the sewage effluent pump (7) is connected to the reflux port at the top of the decarbonization device (2) through a reflux pipeline, and the air outlet at the top of the decarbonization device (2) is connected to the air suction port of the induced draft fan (6); The air inlet at the bottom of the carbon dioxide absorption device (3) is connected to the air outlet of the induced draft fan (6); the upper part and the bottom of the carbon dioxide absorption device (3) are respectively provided with a circulating liquid inlet and a circulating liquid outlet; a circulating pump (8) is provided between the circulating liquid inlet and the circulating liquid outlet; the air outlet at the top of the carbon dioxide absorption device (3) is connected to the stripping gas inlet pipeline via a stripping gas return pipeline to form a circulation loop; The oil removal device (1) has a first aeration assembly (12) in communication with a stripping gas inlet pipeline at its lower inner portion, the decarbonization device (2) has a second aeration assembly (13) in communication with a stripping gas inlet pipeline at its lower inner portion, and the carbon dioxide absorption device (3) has a third aeration assembly (14) in communication with an air inlet at its lower inner portion; A spray assembly (16) connected to the liquid inlet is provided at the upper part of the decarbonization device (2); the other end of the spray assembly (16) is connected to the reflux port; a rotating baffle assembly (17) is provided on one side of the middle part of the spray assembly (16); and a plurality of drainage ribs (18) are provided in the spray assembly (16); The oil removal device (1), the carbon removal device (2) and the carbon dioxide absorption device (3) are all provided with a demister (15) at the top; The spray assembly (16) comprises a spray main pipe (161), one end of the spray main pipe (161) being connected to a liquid inlet of the decarburization device (2), the other end of the spray main pipe (161) being connected to a reflux port of the decarburization device (2), symmetrically arranged spray branch pipes (162) being provided on both sides of the spray main pipe (161), a plurality of spray branch pipes (162) being provided, and one end of the spray branch pipe (162) being connected to the spray main pipe (161). The other end is connected to the inner wall of the decarburization device (2), the bottom of the spray main pipe (161) and the spray branch pipe (162) are provided with a plurality of nozzles (163), the spray main pipe (161) and the spray branch pipe (162) are provided with a plurality of cyclones (164), the bottom of the cyclone (164) is connected to the top of the nozzle (163), and the spray main pipe (161) and the spray branch pipe (162) are both provided with a plurality of drainage ribs (18); The rotating baffle assembly (17) is located at one side of the connection between the middle of the spray main pipe (161) and the spray branch pipe (162), and the rotating baffle assembly (17) comprises a connecting rod (171) installed in the spray main pipe (161), and a first baffle (172) and a second baffle (173) are rotatably provided on the connecting rod (171), and the first baffle (172) and the second baffle (173) are both semicircular, and the first baffle (172) and the second baffle (173) can form a circle, and the first baffle (172) and the connecting rod (171) are connected to the spray main pipe (161). A first torsion spring (174) sleeved on the outer surface of the connecting rod (171) is connected between the two rods (171); a second torsion spring (175) sleeved on the outer surface of the connecting rod (171) is connected between the second baffle plate (173) and the connecting rod (171); a stopper (176) is provided on one side of the connecting rod (171); and the stopper (176) is capable of contacting the side surfaces of the first baffle plate (172) and the second baffle plate (173); and sealing strips (177) are installed on the arcuate edges of the first baffle plate (172) and the second baffle plate (173).

2. The sewage negative pressure gas lift oil removal and carbon dioxide removal system according to claim 1, characterized in that: The stripping gas enters the stripping gas inlet pipeline through the blower (5), and the stripping gas return pipeline is connected to the stripping gas inlet pipeline through the blower (5). By adjusting the rotation speed of the blower (5) and the induced draft fan (6), a negative pressure value is formed in the oil removal device (1) and the decarbonization device (2), and the negative pressure value is maintained at -15KPa to -5KPa.

3. The sewage negative pressure gas lift oil removal and carbon dioxide removal system according to claim 2, characterized in that: A pipeline mixer (4) is provided on the sewage input pipeline, the liquid inlet of the pipeline mixer (4) is also connected to the demulsifier filling device (9), and the liquid outlet of the pipeline mixer (4) is connected to the liquid inlet at the bottom of the oil removal device (1).

4. The sewage negative pressure gas lift oil removal and carbon dioxide removal system according to claim 3, characterized in that: The first aeration component (12) comprises a first aeration pipe (121) connected to the air stripping gas inlet pipeline, a plurality of nozzles (122) are provided at the top of the first aeration pipe (121), a first spiral blade (123) is rotatably installed in the nozzle (122) of the first aeration pipe (121), and a plurality of first micropores (124) are opened at the top of the nozzle (122) of the first aeration pipe (121).

5. The sewage negative pressure gas lift oil removal and carbon dioxide removal system according to claim 4, characterized in that: The second aeration component (13) has the same structure as the third aeration component (14), the second aeration component (13) comprising a second aeration pipe (131) connected to the air stripping gas inlet pipe, a plurality of flow diversion columns (132) being provided at the top of the second aeration pipe (131), a plurality of second micropores (133) being evenly distributed on the side walls of the flow diversion columns (132).

6. The sewage negative pressure gas stripping oil removal and carbon dioxide removal system according to claim 5, characterized in that: The spray head (163) at the bottom of the spray branch pipe (162) comprises a connecting pipe (1631) connected to the bottom of the cyclone (164); the bottom of the connecting pipe (1631) is connected to the hemispherical head (1632); a threaded groove (1633) is provided on the inner wall of the connecting pipe (1631); a plurality of third micro-holes (1634) are evenly distributed on the connecting pipe (1631) and the hemispherical head (1632); and the third micro-holes (1634) are gradually arranged from horizontal to vertical from top to bottom.

7. The sewage negative pressure gas lift oil removal and carbon dioxide removal system according to claim 6, characterized in that: The cyclone (164) comprises an inner hole (1641) connected to the top of the spray head (163) at the bottom of the spray branch pipe (162); a plurality of swirl chambers (1642) are evenly distributed on the side wall of the cyclone (164); the swirl chambers (1642) are connected to the inner hole (1641); and swirl blades (1643) are formed between each pair of the swirl chambers (1642).

8. A process for the wastewater negative pressure gas stripping oil removal and carbon dioxide removal system according to claim 7, characterized in that: The steps include: 1) Oil removal: the oily and carbon dioxide-containing sewage is fed into the pipeline mixer (4) through the boosting effect of the pump, the demulsifier is added into the pipeline mixer (4) through the demulsifier filling device (9), and enters the oil removal device (1) together with the oily and carbon dioxide-containing sewage, the stripping gas enters the first aeration pipe (121) of the oil removal device (1) through the blower (5), and the stripping gas is sprayed from the first micropore (124) of the nozzle (122) to aerate the sewage to demulsify and remove oil by flotation. After demulsification, the oil in the sewage is carried to the upper layer of the sewage by the stripping gas and discharged from the oil discharge port. At the same time, the stripping gas carries out part of the carbon dioxide dissolved in the sewage, passes through the demister (15) at the top of the oil removal device (1), and is discharged from the top of the oil removal device (1) through the negative pressure suction of the induced draft fan (6); 2) Decarbonization: the sewage overflowing from the deoiling device (1) enters the spray main pipe (161) in the decarbonization device (2), and then enters the spray branch pipe (162). The sewage enters the spray head (163) through the cyclone (164) and is sprayed out from the third micropore (1634). The stripping gas enters the second aeration pipe (131) of the decarbonization device (2) from the air inlet at the bottom of the decarbonization device (2). The stripping gas is discharged from the second micropore (133) on the diverter column (132), so that the stripping gas and the sewage are in gas-liquid countercurrent contact. The stripping gas carries away the carbon dioxide on the surface of the sewage. The stripping gas containing carbon dioxide passes through the demister (15) at the top of the decarbonization device (2), and is discharged from the top of the decarbonization device (2) through the negative pressure suction of the induced draft fan (6); 3) Circulation absorption: The stripping gas containing carbon dioxide is introduced into the carbon dioxide absorption device (3) through the induced draft fan (6). The carbon dioxide absorption device (3) contains alkali solution. The alkali solution absorbs the stripping gas containing carbon dioxide to fix the carbon dioxide, thereby purifying the stripping gas. The purified stripping gas is re-inputted from the stripping gas return pipe into the stripping gas inlet pipe through the blower (5), thereby forming a circulation loop.

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