Air injection development tail gas treatment method and treatment system

Abstract

The invention belongs to the technical field of oil reservoir development, and discloses an air injection development tail gas treatment method and system.The treatment method comprises the steps that firstly, air injection development tail gas is compressed and condensed, and light hydrocarbon in the tail gas is liquefied and then separated from the tail gas; then enabling the compressed and condensed tail gas to pass through a CO2 adsorbent and an N2 adsorbent respectively; mixing air into the tail gas treated by the CO2 adsorbent and the N2 adsorbent, and carrying out combustion treatment on the tail gas mixed with the air; and injecting the combusted tail gas into limestone slurry and / or spraying the limestone slurry into the tail gas. According to the air injection development tail gas treatment method and treatment system, the tail gas can be recycled and treated economically and efficiently, and the safety is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil reservoir development, and particularly relates to an air injection development tail gas treatment method and system. BACKGROUND

[0002] Compared with tail gas treatment of natural gas injection development of oil reservoirs, tail gas treatment of air injection (including reduced oxygen air) development of oil reservoirs is more difficult. In the process of air injection development of oil reservoirs, O2 in air and underground crude oil have low-temperature and high-temperature oxidation reactions, O2 is consumed, N2, CO2 and other hydrocarbon and non-hydrocarbon gases are discharged to form flue gas tail gas, in which the content of light hydrocarbon is only 5-10%, and other gases account for about 85-90%. Ordinary separation methods cannot completely separate hydrocarbon gases, resulting in waste of energy. Deep cold recovery as a relatively complete separation technology for low light hydrocarbon tail gas, the separated gas may contain H2S gas, which cannot be directly discharged into the atmosphere and needs to be further treated.

[0003] At present, there are several methods for further treatment of tail gas after deep cold recovery:

[0004] 1. Incineration technology: the commonly used combustion methods include flare combustion and incinerator combustion. Flare combustion is commonly used in the case of large tail gas discharge, containing part of fuel gas, and the components are difficult to separate and recover or the recovery is not economical. Incinerator combustion has the advantages of small occupied area, low operation cost and high recycling degree. The tail gas treatment method has the advantages of simple process and convenient operation. However, the lower explosion limit of light hydrocarbon contained in the tail gas after deep cold recovery is low, for example, the lower explosion limit of methane is 5%, and the lower explosion limit of ethane is 3%, which is easy to explode during combustion, and the heat value of tail gas is low, which is unstable.

[0005] 2. Dry / wet desulfurization technology: dry desulfurization technology is to concentrate desulfurization at the desulfurization point after the production well produced gas is metered at the wellhead. The desulfurization point adopts a three-tower desulfurization process integrating separation, cooling and desulfurization process, which can be operated in series and parallel, and the content of H2S after removal is ≤6mg / m3, and the effect of removing H2S is good; wet desulfurization technology, by referring to LO-CAT liquid phase oxidation catalysis technology, for the case of large amount of oilfield associated gas and relatively low sulfur potential, the gas containing H2S is introduced into the absorption device and contacted with the catalyst solution, and H2S is converted into elemental sulfur. Dry / wet desulfurization technology requires high cost of reagent and small treatment capacity.

[0006] 3. CO2 capture technology: common capture methods include adsorption, amine absorption, ionic liquid absorption, membrane separation and membrane-based absorption, etc. The principle of adsorption is to separate and recover CO2 by using the selective and reversible adsorption of solid adsorbents on CO2 in the raw gas mixture. According to the adsorption and desorption temperature, solid adsorption can be divided into low temperature (<200℃), medium temperature (200-400℃) and high temperature (>400℃). The advantages of amine absorption method are simple operation, large absorption capacity, and the disadvantages are high cost of absorbent regeneration, secondary pollution and large energy consumption. Compared with traditional organic solvents, ionic liquid absorption method has the advantages of low vapor pressure, recyclable, high CO2 absorption load, good thermal stability, etc. Membrane separation is based on the principle of selective separation of gases according to the permeation rate difference of each component gas in the raw gas. According to the different membrane materials, it is mainly divided into polymer membrane, inorganic membrane, etc. Membrane-based absorption is a new gas separation technology combining membrane contactor and solution absorption gas technology.

[0007] The CO2 content in the tail gas produced by fire flooding fluctuates greatly, and contains a part of sulfur-containing gas. It is difficult to meet the emission standard and the economy is poor to capture CO2 in the tail gas alone.

[0008] 4. Acid gas reinjection technology: acid gas reinjection refers to injecting the acid gas (mainly CO2 and H2S) captured from the oil and gas industry or other large emission sources into non-operating or non-economic formations (such as depleted oil and gas reservoirs) through wellbore pressurization for storage. This process is suitable for treating tail gas with high acid gas content, and acid gas leakage is prone to occur. SUMMARY

[0009] One of the purposes of the present application is to provide an air injection development tail gas treatment method which can effectively recover and reuse the associated gas in the air injection development tail gas and meet the safety and environmental protection emission requirements.

[0010] To achieve this purpose, the technical scheme adopted by the present application is as follows:

[0011] An air injection development tail gas treatment method, comprising the following steps:

[0012] S1, compressing and condensing the air injection development tail gas, so that the light hydrocarbon in the tail gas is liquefied and separated from the tail gas;

[0013] S2, passing the compressed and condensed tail gas through CO2 adsorbent and N2 adsorbent respectively;

[0014] S3, mixing air into the tail gas, and then burning the tail gas mixed with air;

[0015] S4, injecting the tail gas after burning into a limestone slurry and / or spraying the limestone slurry into the tail gas.

[0016] Another object of the present application is to provide an air injection development tail gas treatment system for implementing the air injection development tail gas treatment method described above, comprising:

[0017] a cryogenic recovery module, the cryogenic recovery module comprising a compression condensing device configured to condense low hydrocarbon in the tail gas into condensate, and a condensate recovery tank configured to recover the condensate;

[0018] a CO2 separation module, the CO2 separation module comprising a CO2 adsorbing device containing a CO2 adsorbent capable of adsorbing CO2 in the tail gas treated by the compression condensing device;

[0019] a N2 separation module, the N2 separation module comprising a N2 adsorbing device containing a N2 adsorbent capable of adsorbing N2 in the tail gas treated by the compression condensing device;

[0020] a combustion module, the combustion module comprising an air mixer, a combustion boiler and a fan, the fan being connected to the air mixer to pump air and the tail gas passing through the CO2 separation module and the N2 separation module into the air mixer at the same time, the air mixer being connected to the combustion boiler, and the combustion boiler being capable of burning the tail gas mixed with air;

[0021] a desulfurization tower connected to the combustion boiler, the desulfurization tower containing a limestone slurry.

[0022] Preferably, the combustion boiler is provided with a heat exchange pipe, one end of the heat exchange pipe being connected to an external water supply device, and the other end being connected to a heat user.

[0023] Preferably, the desulfurization tower is provided with a spraying assembly capable of spraying the limestone slurry.

[0024] Preferably, the cryogenic recovery module further comprises an oil-water separation device and an oil storage tank, the oil-water separation device being connected to the oil storage tank and the condensate recovery tank, and a first switch valve being provided between the oil-water separation device and the condensate recovery tank.

[0025] Preferably, the cryogenic recovery module further comprises an adjusting valve and a gas flow meter provided at the inlet end of the compression condensing device.

[0026] Preferably, the combustion module further comprises a single-flow valve and a gas pressure stabilizer, the gas pressure stabilizer and the single-flow valve being sequentially provided between the air mixer and the combustion boiler.

[0027] As preferred, the CO2 separation module further comprises a CO2 recovery tank, the CO2 recovery tank being connected with the CO2 adsorption device, and a second switch valve being arranged between the CO2 recovery tank and the CO2 adsorption device.

[0028] As preferred, the N2 separation module further comprises an N2 recovery tank, the N2 recovery tank being connected with the N2 adsorption device, and a third switch valve being arranged between the N2 recovery tank and the N2 adsorption device.

[0029] As preferred, a component monitor is further arranged at the outlet end of the combustion boiler, the component monitor being configured to monitor the content of each component in the tail gas, including SO2.

[0030] The air injection development tail gas treatment method and treatment system in the present application can condense most of the light hydrocarbon into condensate liquid for recovery by means of compression and condensation, and separate CO2 and N2 from the tail gas by means of CO2 adsorbent and N2 adsorbent, so that the tail gas can be subjected to combustion treatment, the risk of explosion during combustion of the tail gas is reduced by means of mixing with air before combustion treatment, H2S in the tail gas is converted into SO2 by combustion, and SO2 can be removed by passing into limestone slurry with low cost, so that the tail gas can reach the emission standard, the whole tail gas treatment process is economical and efficient, and the safety is high. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a structural schematic view of the air injection development tail gas treatment system in the embodiment of the present application.

[0032] In the figure:

[0033] 1, compression and condensation device; 2, condensate liquid recovery tank; 3, oil-water separation device; 4, oil storage tank; 5, CO2 adsorption device; 6, CO2 recovery tank; 7, N2 adsorption device; 8, N2 recovery tank; 9, air mixer; 10, pressure stabilizer; 11, single-flow valve; 12, combustion boiler; 13, heat exchange pipe; 14, desulfurization tower; 15, component monitor; 16, regulating valve; 17, gas flow meter. DETAILED DESCRIPTION

[0034] The present application will be further described in detail below in combination with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, but not all the structures.

[0035] In the description of the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] In the present application, unless otherwise explicitly specified and limited, "on" or "under" the first feature of the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0037] In the description of the present embodiment, the terms "up", "down", "left", "right" and other orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the modules or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only used to distinguish in description, and have no special meaning.

[0038] Embodiment one:

[0039] The present embodiment proposes a method for treating tail gas generated by air injection development, which is used for treating tail gas generated by air injection development, and mainly includes the following steps:

[0040] S1, the tail gas of air injection development is compressed and condensed, so that the light hydrocarbon in the tail gas is liquefied, thereby separating from the tail gas.

[0041] According to the dew point of light hydrocarbon, in order to reduce the operating energy consumption while taking into account the effective separation of gas, the preset gas pressure is preferably 0.8-1.2 MPa, and the precooling temperature is preferably 0-30℃. When the preset gas pressure and precooling temperature range, the light hydrocarbon in the tail gas except methane can be condensed into liquid and precipitated, such as ethane, propane and the like. When specifically setting, the above range can be adjusted according to the change of component content.

[0042] It can be understood that, in the compression condensation process, the water vapor in the air injection development tail gas will also be condensed into liquid water. In order to realize the recovery of light hydrocarbons, the condensed liquid obtained after compression condensation is subjected to oil-water separation operation, so as to separate the condensed oil (light hydrocarbons except methane) and water.

[0043] After compression condensation, most of the light hydrocarbon substances are recovered, at this time, the main components of the tail gas are CO2, N2, a small amount of hydrocarbon gas (mainly methane) and H2S.

[0044] S2, the compressed and condensed tail gas is respectively introduced into a CO2 adsorbent and a N2 adsorbent, and CO2 and N2 are adsorbed.

[0045] It should be noted that the CO2 adsorbent is still in a pressurized environment when adsorbing CO2, and the gas pressure is in the range of 0.8-1.2 MPa. After the tail gas treatment is completed, it needs to be promptly depressurized and desorbed, for example, the gas pressure is reduced to below 0.1 kpa, so as to recover and utilize CO2 and realize the reuse of CO2 adsorbent, thereby reducing the CO2 recovery cost. The N2 adsorbent is the same, and the adsorption of N2 is realized in a pressurized environment, and the desorption is realized after the gas pressure is reduced, so as to realize the recovery and utilization of N2.

[0046] In this embodiment, the CO2 adsorbent and the N2 adsorbent are both selected from metal organic framework compounds containing unsaturated nitrogen atoms. The metal organic framework compound containing unsaturated nitrogen atoms has strong adsorption capacity for N2 and CO2, and the purity can reach 99%, and it can be reused. The principle of the metal organic framework compound containing unsaturated nitrogen atoms adsorbing gas belongs to the prior art, and will not be described here. It should be emphasized that, since the pore size of the metal organic framework compound containing unsaturated nitrogen atoms used in the N2 adsorbent is smaller than that of the CO2 adsorbent, the tail gas is first introduced into the CO2 adsorbent and then introduced into the N2 adsorbent.

[0047] S3, air is mixed into the tail gas discharged from step S2 to reduce the concentration of combustible gas to below 25% of the lower explosive limit, and the tail gas mixed with air is subjected to combustion treatment.

[0048] In the combustion process, the light hydrocarbons and H2S in the tail gas are oxidized to generate SO2, CO2 and H2O and generate a large amount of heat, and the generated heat can be used to heat cold water and supply heat to heat users.

[0049] S4, the tail gas after combustion treatment is injected into a limestone slurry and / or limestone slurry is sprayed into the tail gas, so that the SO2 generated by the conversion of the sulfur component of H2S after combustion is absorbed to form calcium sulfite, and the calcium sulfite can be continuously produced for gypsum use. The excess limestone slurry can also be recycled. The concentration of the limestone slurry is preferably 25%.

[0050] It should be noted that when the limestone slurry is sprayed to the tail gas, the spraying direction of the limestone slurry is opposite to the flowing direction of the tail gas, so as to increase the contact area of the tail gas and the limestone slurry, and further improve the desulfurization effect.

[0051] S5, component monitoring is performed on the tail gas after the treatment in step S4, if the light hydrocarbon or H2S is still over standard, the treatment speed of the tail gas can be reduced, or the air mixing amount is increased and the combustion temperature is increased; if the SO2 is over standard, the concentration or spraying amount of the limestone slurry is increased, of course, the SO2 in the tail gas can also be fully contacted with the limestone slurry by reducing the tail gas treatment speed, so as to reduce the SO2 content in the finally discharged gas.

[0052] The above air injection development tail gas treatment method adopts a gas comprehensive utilization and recovery process of "condensation compression + decarburization + denitrification + mixing with air and then combustion + desulfurization", first, a large amount of light hydrocarbon is recovered by condensation compression, then CO2 and N2 are adsorbed respectively, the heat value of the tail gas is increased, then the part of the light hydrocarbon and H2S in the tail gas which is difficult to be recovered is converted into CO2 and SO2 by combustion and then absorbed by the limestone slurry, so that the tail gas reaches the emission standard, and the combustion safety is improved by the way of air injection before combustion. The whole treatment process ensures the effective recycling of the associated gas in the tail gas, safe and environmentally friendly emission, and a large amount of heat is generated during gas combustion, therefore, the combustion method is adopted to treat the waste gas (mainly H2S) and the small amount of methane which cannot be recycled twice, not only can the gas concentration be reduced to below the explosion risk value, but also the cost of tail gas treatment can be reduced, at the same time, the heat generated during combustion can be used to heat cold water for heating, which is economic and efficient. After the combustion of H2S, the S component is converted into SO2, and the limestone slurry with low cost can realize desulfurization, the generated calcium sulfite can continue to produce gypsum, and the remaining limestone slurry can also be recycled, further reducing the cost of tail gas treatment.

[0053] Example two

[0054] Reference Figure 1As shown, the air injection development tail gas treatment system in the embodiment is used to implement the air injection development tail gas treatment method mentioned in the above embodiment, and comprises a cryogenic recovery module, a CO2 separation module, an N2 separation module, a combustion module, and a desulfurization tower 14. The cryogenic recovery module comprises a compression condensation device 1 and a condensate recovery tank 2. The compression condensation device 1 is used to condense low hydrocarbon in the tail gas into condensate. The condensate recovery tank 2 is used to recover the condensate. The CO2 separation module comprises a CO2 adsorption device 5 containing a CO2 adsorbent, which can adsorb CO2 in the tail gas after compression condensation treatment. The N2 separation module comprises an N2 adsorption device 7 provided with an N2 adsorbent, which can adsorb N2 in the tail gas after compression condensation treatment. The combustion module comprises an air mixer 9, a combustion boiler 12, and a fan. The fan is connected with the air mixer 9 to pump air and the tail gas treated by the CO2 separation module and the N2 separation module into the air mixer 9 at the same time, so that the tail gas is mixed with the air, and the concentration of combustible gas in the tail gas is reduced to below 25% of the lower explosive limit. The air mixer 9 is communicated with the combustion boiler 12. The combustion boiler 12 can burn the tail gas mixed with the air. The desulfurization tower 14 is connected with the combustion boiler 12 and contains limestone slurry for absorbing SO2 generated by combustion.

[0055] The air injection development tail gas treatment system uses the compression condensation device 1 to separate light hydrocarbon in the tail gas into condensate, and then uses the CO2 separation module and the N2 separation module to separate CO2 from the tail gas. After the above treatment, a small amount of light hydrocarbon and H2S and other dangerous gases still exist in the tail gas, which cannot be directly discharged. Therefore, the fan and the air mixer 9 are used to mix the tail gas with air to improve the combustion heat value and reduce the concentration of dangerous gases below the dangerous value. Then, the SO2 formed after combustion is introduced into the desulfurization tower 14 to react with the limestone slurry, which greatly reduces the desulfurization cost. After various recovery and oxidation treatments, the tail gas can meet the standard for safe discharge and can be directly discharged into the air.

[0056] In the embodiment, in order to fully utilize the heat generated in the combustion process of the combustion boiler 12, the combustion boiler 12 is provided with heat exchange pipes 13 arranged in the form of coils in the combustion boiler 12. One end of the heat exchange pipes 13 is connected with an external water supply device, and the other end is connected with a heat user.

[0057] After the tail gas mixed with air enters the combustion boiler 12, high-temperature oxidation reaction occurs under the action of the burner of the combustion boiler 12 to form SO2+CO2+H2O. The generated high temperature heats the cold water in the heat exchange pipes 13, and the heat generated by the combustion of combustible gas is fully utilized.

[0058] In this embodiment, the desulfurization tower 14 is provided with a spraying assembly, which can spray the limestone slurry to make the tail gas fully contact with the limestone slurry to react. Specifically, the spraying assembly includes a water pump, a water pipe and a spray head, the water pipe is connected with the water pump and the spray head, the water pump can suck the limestone slurry in the desulfurization tower 14 and spray the limestone slurry through the spray head.

[0059] To further improve the reaction efficiency, the direction in which the spray head sprays the limestone slurry is opposite to the direction in which the tail gas flows in the desulfurization tower 14. That is, the spray head is located above the air inlet of the desulfurization tower 14.

[0060] Reference Figure 1 As shown, the cryogenic recovery module further includes an oil-water separation device 3 and an oil storage tank 4, the oil-water separation device 3 is connected with the oil storage tank 4 and the condensate recovery tank 2, and a first switch valve is arranged between the oil-water separation device 3 and the condensate recovery tank 2. After the tail gas treatment is completed, the oil-water separation device 3 is communicated with the condensate recovery tank 2 to separate the condensate produced after being compressed and condensed by the compression and condensation device 1, and the light hydrocarbon obtained after the separation is stored in the oil storage tank 4.

[0061] In this embodiment, the cryogenic recovery module further includes an adjusting valve 16 arranged at the inlet end of the compression and condensation device 1 and a gas flow meter 17, the gas flow meter 17 is used to measure the flow of the tail gas entering the compression and condensation device 1, and the adjusting valve 16 can adjust the speed of the tail gas entering the cryogenic recovery module to adjust the tail gas treatment speed.

[0062] The combustion module further includes a single-flow valve 11 and a gas pressure stabilizer 10, the gas pressure stabilizer 10 and the single-flow valve 11 are sequentially arranged between the air mixer 9 and the combustion boiler 12, the fan pumps air into the air mixer 9 to mix with the tail gas, the tail gas mixed with air passes through the gas pressure stabilizer 10 and the single-flow valve 11, the gas pressure stabilizer 10 keeps the pressure of the tail gas at 0.5 Mpa, and the single-flow valve 11 can avoid backflow of the tail gas after high-temperature oxidation and expansion in the combustion boiler 12.

[0063] In this embodiment, the CO2 separation module further includes a CO2 recovery tank 6, the CO2 recovery tank 6 is connected with the CO2 adsorption device 5, and a second switch valve is arranged between the CO2 recovery tank 6 and the CO2 adsorption device 5. After the tail gas treatment is completed, the second switch valve is opened to communicate the CO2 recovery tank 6 and the CO2 adsorption device 5, the gas pressure in the CO2 adsorption device 5 decreases, and the CO2 desorption enters the CO2 recovery tank 6.

[0064] Similarly, the N2 separation module includes an N2 recovery tank 8, the N2 recovery tank 8 is connected with the N2 adsorption device 7, and a third switch valve is arranged between the N2 recovery tank 8 and the N2 adsorption device 7. After the tail gas treatment is completed, the third switch valve is opened to communicate the N2 recovery tank 8 and the N2 adsorption device 7, the gas pressure in the N2 adsorption device 7 decreases, and the N2 desorption enters the N2 recovery tank 8.

[0065] With reference to the foregoing description Figure 1 As shown, the air injection development tail gas treatment system further comprises a component monitor 15 arranged at the outlet end of the combustion boiler 12, which is used to monitor the content of each component in the tail gas, including SO2. If the content of light hydrocarbon or H2S exceeds the standard, the air quantity entering the air mixer 9 can be increased by increasing the fan speed, or the combustion speed of the combustion boiler 12 can be increased, and the tail gas flow rate can also be reduced by adjusting the regulating valve 16. If the content of SO2 exceeds the standard, the limestone slurry concentration or spraying speed in the desulfurization tower 14 can be increased, or the tail gas flow rate can be reduced by adjusting the regulating valve 16.

[0066] The air injection development tail gas treatment system further comprises a component monitor 15 arranged at the outlet end of the combustion boiler 12, which is used to monitor the content of each component in the tail gas, including SO2. If the content of light hydrocarbon or H2S exceeds the standard, the air quantity entering the air mixer 9 can be increased by increasing the fan speed, or the combustion speed of the combustion boiler 12 can be increased, and the tail gas flow rate can also be reduced by adjusting the regulating valve 16. If the content of SO2 exceeds the standard, the limestone slurry concentration or spraying speed in the desulfurization tower 14 can be increased, or the tail gas flow rate can be reduced by adjusting the regulating valve 16.

[0067] The air injection development tail gas treatment system further comprises a controller and an alarm module, both of which are electrically connected to the component monitor 15. When the controller receives a signal that the content of light hydrocarbon or H2S or SO2 exceeds the standard from the component monitor 15, the controller sends an instruction to the alarm module, and the alarm module sends an alarm. Specifically, the alarm module can be selected from a sound alarm and / or a light alarm.

[0068] Further, in order to realize automatic adjustment, the regulating valve 16 is selected to be an electromagnetic valve, and the controller is electrically connected to the water pump in the desulfurization tower 14 and the combustion boiler 12. When the controller receives a signal that the content of light hydrocarbon or H2S exceeds the standard from the component monitor 15, the controller can directly send an instruction to the regulating valve 16 and / or the combustion boiler 12 to reduce the speed of the tail gas entering the deep cooling recovery module and increase the combustion speed of the combustion boiler 12. When the controller receives a signal that the content of SO2 exceeds the standard from the component monitor 15, the controller can send an instruction to the regulating valve 16 and / or the water pump to reduce the speed of the tail gas entering the deep cooling module and increase the efficiency of the spraying module spraying the limestone slurry.

[0069] Obviously, the above embodiments of the present application are only examples for clear illustration of the present application, and are not intended to limit the embodiments of the present application. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present application. It is unnecessary and impossible to enumerate all the embodiments. Any modification, equivalent substitution and improvement within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. An air injection exhaust gas treatment method, characterized in that, Includes the following steps: S1. The exhaust gas from the air injection process is compressed and condensed to liquefy the light hydrocarbons in the exhaust gas and remove them from the exhaust gas. S2. The exhaust gas after compression and condensation is passed through CO2 adsorbent and N2 adsorbent respectively; S3. Introduce air into the exhaust gas and then combust the exhaust gas containing the air. S4. Inject the exhaust gas after combustion treatment into limestone slurry and / or spray limestone slurry into the exhaust gas.

2. An air-injection development exhaust gas treatment system, used to implement the air-injection development exhaust gas treatment method of claim 1, characterized in that, include: The cryogenic recovery module includes a compression condensation device (1) and a condensate recovery tank (2). The compression condensation device (1) is configured to condense low hydrocarbons in the exhaust gas into condensate, and the condensate recovery tank (2) is configured to recover the condensate. The CO2 separation module includes a CO2 adsorption device (5), which contains a CO2 adsorbent and is capable of adsorbing CO2 in the exhaust gas after being treated by the compression and condensation device (1). The N2 separation module includes an N2 adsorption device (7), which contains an N2 adsorbent and is capable of adsorbing N2 in the exhaust gas after it has been treated by the compression and condensation device (1). The combustion module includes an air mixer (9), a combustion boiler (12), and a fan. The fan is connected to the air mixer (9) to simultaneously pump air and exhaust gas processed by the CO2 separation module and the N2 separation module into the air mixer (9). The air mixer (9) is connected to the combustion boiler (12), which is capable of burning the exhaust gas mixed with air. A desulfurization tower (14) is connected to the combustion boiler (12), and the desulfurization tower (14) contains limestone slurry.

3. The air injection exhaust gas treatment system according to claim 2, characterized in that, The combustion boiler (12) is equipped with a heat exchange tube (13), one end of which is used to connect to an external water supply device and the other end is used to connect to a heat user.

4. The air injection exhaust gas treatment system according to claim 2, characterized in that, The desulfurization tower (14) is equipped with a spraying component, which can spray limestone slurry.

5. The air injection exhaust gas treatment system according to claim 2, characterized in that, The cryogenic recovery module also includes an oil-water separation device (3) and an oil storage tank (4). The oil-water separation device (3) is connected to the oil storage tank (4) and the condensate recovery tank (2). A first switching valve is provided between the oil-water separation device (3) and the condensate recovery tank (2).

6. The air injection exhaust gas treatment system according to claim 2, characterized in that, The cryogenic recovery module also includes a regulating valve (16) and a gas flow meter (17) located at the inlet of the compression condensation device (1).

7. The air injection exhaust gas treatment system according to claim 2, characterized in that, The combustion module also includes a one-way valve (11) and a gas regulator (10), which are arranged sequentially between the air mixer (9) and the combustion boiler (12).

8. The air injection exhaust gas treatment system according to claim 2, characterized in that, The CO2 separation module also includes a CO2 recovery tank (6), which is connected to the CO2 adsorption device (5). A second switching valve is provided between the CO2 recovery tank (6) and the CO2 adsorption device (5).

9. The air injection exhaust gas treatment system according to claim 2, characterized in that, The N2 separation module also includes an N2 recovery tank (8), which is connected to the N2 adsorption device (7), and a third switching valve is provided between the N2 recovery tank (8) and the N2 adsorption device (7).

10. The air injection exhaust gas treatment system according to claim 2, characterized in that, It also includes a component monitor (15) installed at the outlet end of the combustion boiler (12), the component monitor (15) being configured to monitor the content of each component, including SO2, in the exhaust gas.

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