Comprehensive treatment process for zero-carbon well site petroleum associated gas

Abstract

The invention relates to a comprehensive treatment process for zero-carbon well site petroleum associated gas. Comprising the following steps that 1, associated gas from an oil well and a multifunctional tank is fed into a movable associated gas purification device to be treated, removed water and hydrocarbon return to the multifunctional tank to achieve yield increase and cost reduction, and removed CO2 is guided into a CCUS system; 2, if the amount of removed CO2 is large, the removed CO2 is conveyed to a chemical methanol or potassium bicarbonate preparation process, purified associated gas generates steam through low-temperature catalytic oxidation equipment to push a screw expander to generate power, and high-temperature gas and liquid discharged from the screw expander return to the multifunctional tank to be used for heating crude oil; and thirdly, power is generated through the screw expander, and the generated power is stored in the skid-mounted movable power storage cabinet and can be adjusted and transferred to other power utilization units through the movable energy storage vehicle. Effective comprehensive utilization, micro-grid closed circulation, zero emission and safe production of energy in the island type area of the oil field are achieved, and the problem of remote well site production is solved.

Description

Technical Field

[0001] This invention relates to the field of associated gas technology, and in particular to a comprehensive treatment process for associated gas in a zero-carbon well site. Background Technology

[0002] Currently, in the petroleum industry, newly developed remote oil and gas blocks lack supporting oil pipeline networks and power grids, so they can only use multi-functional tanks for on-site oil storage and timed oil hauling. For associated gas with large production volume and complex composition, most of it is vented, which not only pollutes the environment but also causes considerable waste in the development of oil and gas fields.

[0003] Furthermore, with the gradual development of shale oil and gas extraction and the application of carbon dioxide enhanced oil recovery (CEOR) technology, the production process of these oil wells is accompanied by a large amount of associated gas. This gas is abundant, complex in composition, and difficult to process, posing numerous challenges to the further development of the oilfield. The problems include: first, the large gas volume can easily cause gas blockage in the gathering and transportation pipelines, leading to system disorder; second, the gas composition is complex, containing water, hydrocarbons, carbon dioxide, etc., causing pollution of the pipeline network and making it impossible to transport or sell externally; third, direct ignition and combustion or external discharge can lead to environmental pollution, failing to meet emission standards and violating environmental regulations; and fourth, the equipment requires a large footprint, has high costs, complex processes, and many uncertainties.

[0004] In response to the above situation, traditionally, chemical / physical methods, or a combination of both, are used to dehydrate, dehydrocarbonize, and decarbonize associated gas. Then, internal combustion engines / gas turbines are used to generate electricity on-site, forming an isolated power grid ("island") power supply mode to ensure the development and operation of the oil field. However, this technical solution is complex, requires large investments, has generator emissions that do not meet standards, and leaves excess natural gas with nowhere to go. As a result, many oil wells still use on-site venting and combustion of associated gas, wasting a large amount of associated gas resources.

[0005] Therefore, we need to develop a zero-carbon well site associated gas integrated treatment process to meet the needs of these oilfields for high efficiency, emission reduction, and energy conservation. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned deficiencies in existing technologies by providing a zero-carbon integrated treatment process for associated gas in oil well sites. This invention combines a clever process design with the integrated configuration of gas purification equipment, low-temperature catalytic oxidation, screw expander generator, power storage, hot potassium alkali decarbonization, and wind, solar, and geothermal energy. This achieves the effective and comprehensive utilization of energy in isolated areas, enabling closed-loop microgrid circulation, zero emissions, and safe production, thus solving the production challenges in remote well sites.

[0007] The zero-carbon well site associated gas integrated treatment process mentioned in this invention includes the following technical solution: 1. Associated gas from oil well (a1) and multi-functional tank (a2) is sent to a mobile associated gas purification device (a3) ​​for treatment. The removed water and hydrocarbons are returned to the multi-functional tank (a2) to increase production and reduce costs, and the removed CO2 is introduced into the CCUS system. 2. If the amount of CO2 removed is large, it will be transported to the methanol or potassium bicarbonate production process (a4). The purified associated gas will be used to generate steam using a low-temperature catalytic oxidation device to drive a screw expander (a5) to generate electricity. The high-temperature gas and liquid from the screw expander will be returned to the multi-functional tank (a2) for heating crude oil. Third, electricity is generated through a screw expander (a5) and stored in a skid-mounted mobile energy storage cabinet (a6). On the one hand, it is used to meet the power needs of various equipment on site. On the other hand, in the event of insufficient gas supply, the skid-mounted mobile energy storage cabinet (a6) can be combined with local wind turbines and solar power generation equipment (a7), or the peak-valley difference can be used to smooth out peaks and valleys and generate green electricity to ensure the power needs of the oilfield. If the gas supply is large and there is surplus power generation, the mobile energy storage vehicle (a8) can be fully utilized to transfer the electricity to other power-consuming units (a9).

[0008] Preferably, the above-mentioned portable associated gas purification device includes a natural gas system, a sewage system, and a refrigeration system. The natural gas system includes a filter, a booster, a natural gas air-cooled radiator (22), and a natural gas heat exchanger (21). The filter is used to filter impurities in the scattered gas, and the booster is used to increase the pressure of the scattered gas. The output end of the booster is connected to the tube inlet of the natural gas heat exchanger (21) through a pipeline and the natural gas air-cooled radiator (22). The tube outlet of the natural gas heat exchanger (21) is connected to the shell inlet of the first evaporator (13) and the second evaporator (14) of the refrigeration system through a pipeline and the natural gas proportional adjustment electric three-way valve (18). The shell outlets of the first evaporator (13) and the second evaporator (14) are respectively connected to the shell inlet of the natural gas heat exchanger (21) through pipelines. The shell outlet of the natural gas heat exchanger (21) discharges the cooled scattered gas.

[0009] Preferably, the above-mentioned refrigeration system includes a cryogenic compressor (1), an oil separator (2), a four-way valve, a first solenoid valve (6), a second solenoid valve (7), a condenser (8), a dryer filter (9), a first electronic expansion valve (11), a second electronic expansion valve (12), a first evaporator (13), and a second evaporator (14). The outlet of the cryogenic compressor (1) is connected to the condenser (8) through a pipeline, the oil separator (2), and the four-way valve. The output end of the condenser (8) is connected to the first electronic expansion valve (11) or the second electronic expansion valve (12) through a pipeline and the dryer filter (9). The output end of the first electronic expansion valve (11) is connected to the first electronic expansion valve (11) or the second electronic expansion valve (12) through a pipeline. The tube side inlet of the first evaporator (13) is connected by a line, and the output end of the second electronic expansion valve (12) is connected to the tube side inlet of the second evaporator (14) through a line; the tube side outlet of the first evaporator (13) is connected to the inlet end of the condenser (8) through a line and the second solenoid valve (7), and is connected to the inlet end of the cryogenic compressor (1) through a second line and the first loop solenoid valve (19); the tube side outlet of the second evaporator (14) is connected to the inlet end of the condenser (8) through a line and the first solenoid valve (6), and is connected to the inlet end of the cryogenic compressor (1) through a second line and the second loop solenoid valve (20).

[0010] Preferably, the above-mentioned sewage system includes a sewage storage tank (23), a first sewage control valve (24), a second sewage control valve (25), and a third sewage control valve (26). The lower shell end of the first evaporator (13) is connected to the side line of the sewage storage tank (23) through a pipeline and the first sewage control valve (24). The lower shell end of the second evaporator (14) is connected to the side line of the sewage storage tank (23) through a pipeline and the second sewage control valve (25). The lower shell end of the natural gas heat exchanger (21) is connected to the side line of the sewage storage tank (23) through a pipeline and the third sewage control valve (26).

[0011] Preferably, under the condition that the first evaporator (13) freezes and the second evaporator (14) heats to melt the ice, the purification process includes the following: The high-temperature and high-pressure refrigerant gas, after being compressed by the low-temperature compressor (1), enters the tube-side inlet of the second evaporator (14) through the oil separator (2), the first four-way valve (3), and the second four-way valve (4), respectively, and starts the heating and de-icing mode. The gas-liquid mixture flows out through the tube-side outlet of the second evaporator (14), and enters the condenser (8) through the pipeline and the first solenoid valve (6) for further cooling and liquefaction. Then, the medium-temperature and high-pressure liquid enters the tube-side inlet of the first evaporator (13) through the dryer filter (9), the liquid level indicator (10), and the first electronic expansion valve (11), where it evaporates and absorbs heat, cooling the natural gas from the natural gas heat exchanger (21) from 0 to 5°C to -25 to -30°C. The refrigerant flows back from the tube-side outlet of the first evaporator (13) through the first loop solenoid valve (19) to the air inlet of the low-temperature compressor (1) to achieve refrigerant circulation.

[0012] Preferably, in the condition of freezing in the first evaporator (13) and precooling in the second evaporator (14), the following is included: After the second evaporator (14) finishes heating and defrosting, instead of directly controlling the function switch between the first evaporator (13) and the second evaporator (14), the second electronic expansion valve (12) is opened slightly to inject a small amount of refrigerant into it. Before the natural gas enters the shell side of the second evaporator (14), the second evaporator (14) is pre-cooled to avoid the natural gas output from the shell side of the second evaporator (14) being substandard due to direct switching. During this period, the high-temperature and high-pressure refrigerant gas compressed by the cryogenic compressor (1) passes through the oil separator (2), the first four-way valve (3), and the second four-way valve (4) to enter the condenser (8) to cool and liquefy into a medium-temperature and high-pressure refrigerant liquid. Then, it passes through the dryer filter (9), and then through the first electronic expansion valve (11) and the second electronic expansion valve (12) to form a low-temperature and low-pressure refrigerant gas. It enters the first evaporator (13) and the second evaporator (14) to freeze the first evaporator (13). The second evaporator (14) is pre-cooled by opening the second electronic expansion valve (12) by a small amount. Finally, the low-temperature and low-pressure refrigerant gas flows from the tube outlet of the first evaporator (13) and the second evaporator (14) to the inlet of the cryogenic compressor (1) to realize the circulation of refrigerant.

[0013] Preferably, in the condition where the first evaporator (13) heats and melts the ice, and the second evaporator (14) freezes the ice, the following is included: When the first evaporator (13) has been in a long-term freezing condition, and the outer wall of the heat exchange coil forms a layer of frost and ice that affects the freezing efficiency, the first evaporator (13) and the second evaporator (14) are switched. At this time, the natural gas proportional regulation electric three-way valve (18) is gradually switched to the natural gas heat exchanger (21) to connect to the second evaporator (14) and to close the connection with the first evaporator (13). Then, the high-temperature and high-pressure refrigerant gas compressed by the low-temperature compressor (1) enters the first evaporator (13) through the oil separator (2), the first four-way valve (3) and the third four-way valve (5), respectively, and starts the de-icing mode. The high-temperature and high-pressure gas-liquid mixture flowing out of the first evaporator (13) enters the condenser (8) through the second solenoid valve (7), and is further cooled and liquefied to form a medium-temperature and high-pressure refrigerant liquid. Then, it passes through the dryer filter (9) and the second electronic expansion valve (12) to form a low-temperature and low-pressure refrigerant gas, which enters the second evaporator (14) to evaporate and absorb heat, cooling the natural gas from the natural gas heat exchanger (21) from 0 to 5°C to -25 to -30°C. The low-temperature and low-pressure refrigerant gas flows back from the tube outlet of the second evaporator (14) through the second loop solenoid valve (20) to the inlet of the low-temperature compressor (1) to realize the circulation of refrigerant.

[0014] Preferably, under the condition of pre-cooling in the first evaporator (13) and freezing in the second evaporator (14), the process includes the following: When ice or frost forms in the second evaporator (14), instead of directly switching the function between the first evaporator (13) and the second evaporator (14), the first electronic expansion valve (11) is opened gradually to inject a small amount of refrigerant into the first evaporator (13). Before the natural gas enters the shell side of the first evaporator (13), the first evaporator (13) is pre-cooled to avoid the sudden switching causing the output natural gas to be substandard. During this period, the high-temperature and high-pressure refrigerant gas compressed by the cryogenic compressor (1) passes through the oil separator (2), the first four-way valve (3) and the third four-way valve (5) respectively and enters the condenser (8) to cool down into a medium-temperature and high-pressure refrigerant liquid. Then it passes through the dryer filter (9), and then through the first electronic expansion valve (11) and the second electronic expansion valve (12) to form a low-temperature and low-pressure refrigerant gas. It enters the first evaporator (13) and the second evaporator (14) respectively to freeze the second evaporator (14). The first evaporator (13) is pre-cooled by opening the first electronic expansion valve (11) by a small amount. Finally, the low-temperature and low-pressure refrigerant gas flows from the tube outlet of the first evaporator (13) and the second evaporator (14) to the inlet of the cryogenic compressor (1) to realize the circulation of refrigerant.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: I. This invention combines a clever process design that integrates gas purification equipment, low-temperature catalytic oxidation, screw expander generator, electric energy storage, hot potassium alkali decarbonization, and wind, solar and geothermal energy. It achieves effective comprehensive utilization of energy in "isolated" areas, with microgrid closed-loop, zero emissions, and safe production. It solves the problem of production in remote well sites and can achieve zero emissions. The entire process has no solid or liquid emissions and no harmful gas emissions. Second, the processing technology of this invention is simple. The purification of associated gas only requires multi-stage cooling and physical separation to remove water, hydrocarbons and carbon dioxide respectively. In addition, the portable associated gas purification device is equipped with two evaporators, which operate alternately and have a pre-cooling function to ensure that the output of natural gas meets the standards. One evaporator removes water and heavy hydrocarbons of C4 and above by cooling, so that scattered natural gas can be effectively utilized. The other evaporator defrosts by heating. Furthermore, by introducing high-temperature refrigerant into the inner cavity of the heat exchange coil to heat the frost and ice layer on the outer wall of the heat exchange coil, the heat diffuses from the inside of the ice layer to the outside, resulting in better defrosting effect. Thus, it achieves continuous production without stopping, energy saving and consumption reduction, intelligent small modular skid-mounted equipment. Third, the present invention uses a low-temperature catalytic oxidation technology equipment to produce steam + screw expander generator set, which is safe and reliable. The CO2 after oxidation reaction is used to heat the multi-functional tank and then enters the potassium alkali reaction device. In the case of insufficient gas supply, geothermal energy can be considered to fill the heating demand. Fourth, this invention uses a mobile energy storage cabinet and a mobile energy storage vehicle to convert chemical energy into safe and high-quality electrical energy, avoiding VOC emissions, protecting the environment, and saving energy. At the same time, combined with light energy and peak-valley power, it can cope with various "island" situations in oilfield production, and fully guarantee the production needs of oilfields in terms of safety, environmental protection, energy saving and consumption reduction. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the entire process of Embodiment 1 of the present invention; Figure 2 This is a connection diagram of the portable associated gas purification device of the present invention; Figure 3 This is a schematic diagram of the entire process of Embodiment 2 of the present invention; In the diagram above: Oil well a1, multi-functional tank a2, mobile associated gas purification device a3, methanol or potassium bicarbonate production process a4, screw expander a5, skid-mounted mobile energy storage cabinet a6, wind turbine and solar power generation equipment a7, mobile energy storage vehicle a8, power unit a9, oil hauling vehicle a10, carbon dioxide activation device a11, cryogenic compressor 1, oil separator 2, first four-way valve 3, second four-way valve 4, third four-way valve 5, first solenoid valve 6, second solenoid valve 7, condenser 8, dry 9. Dry filter, 10. Liquid level indicator, 11. First electronic expansion valve, 12. Second electronic expansion valve, 13. First evaporator, 14. Second evaporator, 15. First pressure relief valve, 16. Second pressure relief valve, 17. Third pressure relief valve, 18. Natural gas proportional regulating electric three-way valve, 19. First circuit solenoid valve, 20. Second circuit solenoid valve, 21. Natural gas heat exchanger, 22. Natural gas air-cooled radiator, 23. Sewage storage tank, 24. First sewage discharge control valve, 25. Second sewage discharge control valve, 26. Third sewage discharge control valve. Detailed Implementation

[0017] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0018] Example 1, referring to Figure 1 The zero-carbon well site associated gas integrated treatment process mentioned in this invention includes the following steps: 1. The associated gas from oil well a1 and multi-functional tank a2 is sent to the mobile associated gas purification device a3 for treatment. The removed water and hydrocarbons are returned to multi-functional tank a2 to increase production and reduce costs, and the removed CO2 is introduced into the CCUS system. 2. If the amount of CO2 removed is large, it will be transported to the methanol or potassium bicarbonate production process a4. The purified associated gas will be used to generate steam using a low-temperature catalytic oxidation device to drive the screw expander a5 to generate electricity. The high-temperature gas and liquid from the screw expander will be returned to the multi-functional tank a2 for heating crude oil. Third, electricity is generated through the screw expander a5 and stored in the skid-mounted mobile energy storage cabinet a6. On the one hand, it is used to meet the power needs of various equipment on site. On the other hand, when the gas supply is insufficient, the skid-mounted mobile energy storage cabinet a6 can be combined with local wind turbines and solar power generation equipment a7, or the peak-valley difference can be used to smooth out peaks and valleys and generate green electricity to ensure the power needs of the oilfield. If the gas supply is large and the power generation is sufficient, the mobile energy storage vehicle a8 can be fully utilized to transfer the electricity to other power-consuming units a9.

[0019] Reference Figure 2The portable associated gas purification device mentioned in this invention includes a natural gas system, a sewage system, and a refrigeration system. The natural gas system includes a filter, a booster compressor, a natural gas air-cooled radiator 22, and a natural gas heat exchanger 21. The filter is used to filter impurities in the scattered gas, and the booster compressor is used to increase the pressure of the scattered gas. The output end of the booster compressor is connected to the tube-side inlet of the natural gas heat exchanger 21 through a pipeline and the natural gas air-cooled radiator 22. The tube-side outlet of the natural gas heat exchanger 21 is connected to the shell-side inlet of the first evaporator 13 and the second evaporator 14 of the refrigeration system through a pipeline and a natural gas proportional adjustment electric three-way valve 18. The shell-side outlets of the first evaporator 13 and the second evaporator 14 are respectively connected to the shell-side inlet of the natural gas heat exchanger 21 through pipelines. The shell-side outlet of the natural gas heat exchanger 21 discharges the cooled scattered gas.

[0020] The aforementioned refrigeration system includes a cryogenic compressor 1, an oil separator 2, a four-way valve, a first solenoid valve 6, a second solenoid valve 7, a condenser 8, a dryer filter 9, a first electronic expansion valve 11, a second electronic expansion valve 12, a first evaporator 13, and a second evaporator 14. The outlet of the cryogenic compressor 1 is connected to the condenser 8 via a pipeline, the oil separator 2, and the four-way valve. The output end of the condenser 8 is connected to either the first electronic expansion valve 11 or the second electronic expansion valve 12 via a pipeline and the dryer filter 9. The output end of the first electronic expansion valve 11 is connected to the first... The tube-side inlet of the evaporator 13 and the output of the second electronic expansion valve 12 are connected to the tube-side inlet of the second evaporator 14 via a pipeline; the tube-side outlet of the first evaporator 13 is connected to the pipeline at the inlet of the condenser 8 via a pipeline and the second solenoid valve 7, and is connected to the inlet of the cryogenic compressor 1 via a second pipeline and the first circuit solenoid valve 19; the tube-side outlet of the second evaporator 14 is connected to the pipeline at the inlet of the condenser 8 via a pipeline and the first solenoid valve 6, and is connected to the inlet of the cryogenic compressor 1 via a second pipeline and the second circuit solenoid valve 20.

[0021] In addition, the above-mentioned sewage system includes a sewage storage tank 23, a first sewage control valve 24, a second sewage control valve 25, and a third sewage control valve 26. The lower end of the shell side of the first evaporator 13 is connected to the side line of the sewage storage tank 23 through a pipeline and the first sewage control valve 24. The lower end of the shell side of the second evaporator 14 is connected to the side line of the sewage storage tank 23 through a pipeline and the second sewage control valve 25. The lower end of the shell side of the natural gas heat exchanger 21 is connected to the side line of the sewage storage tank 23 through a pipeline and the third sewage control valve 26.

[0022] The portable associated gas purification device mentioned in this invention includes four operating conditions, specifically as follows: First, under the condition that the first evaporator 13 is used for freezing and the second evaporator 14 is used for heating and de-icing, the purification process includes the following: The high-temperature, high-pressure refrigerant gas, compressed by the cryogenic compressor 1, enters the tube-side inlet of the second evaporator 14 through the oil separator 2, the first four-way valve 3, and the second four-way valve 4, respectively, to activate the heating and de-icing mode. The gas-liquid mixture flows out through the tube-side outlet of the second evaporator 14, passes through pipelines and the first solenoid valve 6, and enters the condenser 8 for further cooling and liquefaction. Then, the medium-temperature, high-pressure liquid enters the tube-side inlet of the first evaporator 13 through the dryer filter 9, the liquid level indicator 10, and the first electronic expansion valve 11, where it evaporates and absorbs heat, cooling the natural gas from the natural gas heat exchanger 21 from 0 to 5°C to -25 to -30°C. The refrigerant then flows back from the tube-side outlet of the first evaporator 13 to the inlet of the cryogenic compressor 1 through the first loop solenoid valve 19, thus achieving refrigerant circulation.

[0023] Second, under the condition of freezing in the first evaporator 13 and precooling in the second evaporator 14, the following applies: After the second evaporator 14 finishes heating and defrosting, instead of directly controlling the function switch between the first evaporator 13 and the second evaporator 14, the second electronic expansion valve 12 is slightly opened to inject a small amount of refrigerant. Before the natural gas enters the shell side of the second evaporator 14, the second evaporator 14 is pre-cooled to avoid the natural gas output from the shell side of the second evaporator 14 being substandard due to direct switching. During this period, the high-temperature and high-pressure refrigerant gas, after being compressed by the cryogenic compressor 1, passes through the oil separator 2, the first four-way valve 3, and the second four-way valve 4, and enters the condenser 8 to cool and liquefy into a medium-temperature and high-pressure refrigerant liquid. Then, it passes through the dryer filter 9, and then through the first electronic expansion valve 11 and the second electronic expansion valve 12 to form a low-temperature and low-pressure refrigerant gas, which enters the first evaporator 13 and the second evaporator 14, respectively, to freeze the first evaporator 13. The second evaporator 14 is pre-cooled by slightly opening the second electronic expansion valve 12. Finally, the low-temperature and low-pressure refrigerant gas flows from the tube outlet of the first evaporator 13 and the second evaporator 14 to the inlet of the cryogenic compressor 1 to achieve refrigerant circulation.

[0024] Third, under the condition that the first evaporator 13 heats and melts ice while the second evaporator 14 freezes ice, the following applies: When the first evaporator 13 has been in a long-term freezing condition, and the outer wall of the heat exchange coil forms a layer of frost and ice that affects the freezing efficiency, the first evaporator 13 and the second evaporator 14 will switch. At this time, the natural gas proportional regulation electric three-way valve 18 will gradually switch to the natural gas heat exchanger 21 to connect to the second evaporator 14 and close the connection with the first evaporator 13. Then, the high-temperature and high-pressure refrigerant gas, compressed by the cryogenic compressor 1, enters the first evaporator 13 through the oil separator 2, the first four-way valve 3, and the third four-way valve 5, respectively, and starts the de-icing mode. The high-temperature and high-pressure gas-liquid mixture flowing out of the first evaporator 13 enters the condenser 8 through the second solenoid valve 7, where it is further cooled and liquefied to form a medium-temperature and high-pressure refrigerant liquid. Then, it passes through the dryer filter 9 and the second electronic expansion valve 12 to form a low-temperature and low-pressure refrigerant gas, which enters the second evaporator 14 to evaporate and absorb heat, cooling the natural gas from the natural gas heat exchanger 21 from 0 to 5°C to -25 to -30°C. The low-temperature and low-pressure refrigerant gas flows back from the tube outlet of the second evaporator 14 through the second loop solenoid valve 20 to the inlet of the cryogenic compressor 1 to achieve refrigerant circulation.

[0025] Fourth, under the condition of pre-cooling in the first evaporator 13 and freezing in the second evaporator 14, the following process is included: When ice or frost forms in the second evaporator 14, instead of directly switching the function between the first evaporator 13 and the second evaporator 14, the first electronic expansion valve 11 is opened gradually to introduce a small amount of refrigerant into the first evaporator 13. Before the natural gas enters the shell side of the first evaporator 13, the first evaporator 13 is pre-cooled to avoid the output of natural gas failing to meet the standard due to sudden switching. During this period, the high-temperature and high-pressure refrigerant gas, after being compressed by the cryogenic compressor 1, passes through the oil separator 2, the first four-way valve 3, and the third four-way valve 5, and enters the condenser 8 to be cooled into a medium-temperature and high-pressure refrigerant liquid. Then, it passes through the dryer filter 9, and then through the first electronic expansion valve 11 and the second electronic expansion valve 12 to form a low-temperature and low-pressure refrigerant gas, which enters the first evaporator 13 and the second evaporator 14 respectively, thereby freezing the second evaporator 14. The first evaporator 13 is pre-cooled by slightly opening the first electronic expansion valve 11. Finally, the low-temperature and low-pressure refrigerant gas flows from the tube outlet of the first evaporator 13 and the second evaporator 14 to the inlet of the cryogenic compressor 1 to achieve refrigerant circulation.

[0026] Example 2, a zero-carbon well site associated gas integrated treatment process mentioned in this invention, includes the following steps: 1. The associated gas from oil well a1 and multi-functional tank a2 is sent to the mobile associated gas purification device a3 for treatment. The removed water and hydrocarbons are returned to multi-functional tank a2 to increase production and reduce costs, and the removed CO2 is introduced into the CCUS system. 2. If the amount of CO2 removed is large, it will be transported to the methanol or potassium bicarbonate production process a4. The purified associated gas will be used to generate steam using a low-temperature catalytic oxidation device to drive the screw expander a5 to generate electricity. The high-temperature gas and liquid from the screw expander will be returned to the multi-functional tank a2 for heating crude oil. Third, electricity is generated through the screw expander a5 and stored in the skid-mounted mobile energy storage cabinet a6. On the one hand, it is used to meet the power needs of various equipment on site. On the other hand, when the gas supply is insufficient, the skid-mounted mobile energy storage cabinet a6 can be combined with local wind turbines and solar power generation equipment a7, or the peak-valley difference can be used to smooth out peaks and valleys and generate green electricity to ensure the power needs of the oilfield. If the gas supply is large and the power generation is sufficient, the mobile energy storage vehicle a8 can be fully utilized to transfer the electricity to other power-consuming units a9.

[0027] The difference from Example 1 is: Reference Figure 3 In this embodiment, potassium bicarbonate can also be recycled. By reacting the separated carbon dioxide with potassium carbonate and water to generate potassium bicarbonate, it can be sold as fertilizer. On the other hand, depending on the needs of the well site where carbon dioxide is injected, when it is necessary to replenish the carbon dioxide injection, the carbon dioxide activation device a11, that is, the heating device, can be used to regenerate potassium carbonate, water and carbon dioxide, and then the regenerated carbon dioxide can be injected into the well site, thus realizing the function of carbon dioxide injection for oil displacement.

[0028] The above description is merely a partial preferred embodiment of the present invention. Any person skilled in the art can modify the above-described technical solutions or modify them into equivalent technical solutions. Therefore, any simple modifications or equivalent transformations made based on the technical solutions of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A zero-carbon well site associated gas integrated treatment process, characterized by: Includes the following processes:

1. Associated gas from oil well (a1) and multi-functional tank (a2) is sent to a mobile associated gas purification device (a3) ​​for treatment. The removed water and hydrocarbons are returned to the multi-functional tank (a2) to increase production and reduce costs, and the removed CO2 is introduced into the CCUS system.

2. If the amount of CO2 removed is large, it will be transported to the methanol or potassium bicarbonate production process (a4). The purified associated gas will be used to generate steam using a low-temperature catalytic oxidation device to drive a screw expander (a5) to generate electricity. The high-temperature gas and liquid from the screw expander will be returned to the multi-functional tank (a2) for heating crude oil. Third, electricity is generated through a screw expander (a5) and stored in a skid-mounted mobile energy storage cabinet (a6). On the one hand, it is used to meet the power needs of various equipment on site. On the other hand, in the event of insufficient gas supply, the skid-mounted mobile energy storage cabinet (a6) can be combined with local wind turbines and solar power generation equipment (a7), or the peak-valley difference can be used to smooth out peaks and valleys and generate green electricity to ensure the power needs of the oilfield. If the gas supply is large and there is surplus power generation, the mobile energy storage vehicle (a8) can be fully utilized to transfer the electricity to other power-consuming units (a9).

2. The zero-carbon well site associated gas integrated treatment process according to claim 1, characterized in that: The portable associated gas purification device includes a natural gas system, a sewage system, and a refrigeration system. The natural gas system includes a filter, a booster, a natural gas air-cooled radiator (22), and a natural gas heat exchanger (21). The filter is used to filter impurities in the scattered gas. The booster is used to increase the pressure of the scattered gas. The output end of the booster is connected to the tube inlet of the natural gas heat exchanger (21) through a pipeline and the natural gas air-cooled radiator (22). The tube outlet of the natural gas heat exchanger (21) is connected to the shell inlet of the first evaporator (13) and the second evaporator (14) of the refrigeration system through a pipeline and the natural gas proportional adjustment electric three-way valve (18). The shell outlets of the first evaporator (13) and the second evaporator (14) are respectively connected to the shell inlet of the natural gas heat exchanger (21) through pipelines. The shell outlet of the natural gas heat exchanger (21) discharges the cooled scattered gas.

3. The zero-carbon well site associated gas integrated treatment process according to claim 2, characterized in that: The refrigeration system includes a cryogenic compressor (1), an oil separator (2), a four-way valve, a first solenoid valve (6), a second solenoid valve (7), a condenser (8), a dryer filter (9), a first electronic expansion valve (11), a second electronic expansion valve (12), a first evaporator (13), and a second evaporator (14). The outlet of the cryogenic compressor (1) is connected to the condenser (8) via a pipeline, the oil separator (2), and the four-way valve. The output end of the condenser (8) is connected to the first electronic expansion valve (11) or the second electronic expansion valve (12) via a pipeline and the dryer filter (9). The output end of the first electronic expansion valve (11) is connected via a pipeline to... The tube side inlet of the first evaporator (13) is connected to the tube side inlet of the second evaporator (14) via a pipeline; the tube side outlet of the first evaporator (13) is connected to the pipeline at the inlet of the condenser (8) via a pipeline and the second solenoid valve (7), and is connected to the inlet of the cryogenic compressor (1) via a second pipeline and the first loop solenoid valve (19); the tube side outlet of the second evaporator (14) is connected to the pipeline at the inlet of the condenser (8) via a pipeline and the first solenoid valve (6), and is connected to the inlet of the cryogenic compressor (1) via a second pipeline and the second loop solenoid valve (20).

4. The zero-carbon well site associated gas integrated treatment process according to claim 3, characterized in that: The sewage system includes a sewage storage tank (23), a first sewage control valve (24), a second sewage control valve (25), and a third sewage control valve (26). The lower shell end of the first evaporator (13) is connected to the side line of the sewage storage tank (23) through a pipeline and the first sewage control valve (24). The lower shell end of the second evaporator (14) is connected to the side line of the sewage storage tank (23) through a pipeline and the second sewage control valve (25). The lower shell end of the natural gas heat exchanger (21) is connected to the side line of the sewage storage tank (23) through a pipeline and the third sewage control valve (26).

5. The zero-carbon well site associated gas integrated treatment process according to claim 4, characterized in that: in Under the condition that the first evaporator (13) freezes and the second evaporator (14) heats to melt the ice, the purification process includes the following: The high-temperature and high-pressure refrigerant gas, after being compressed by the low-temperature compressor (1), enters the tube-side inlet of the second evaporator (14) through the oil separator (2), the first four-way valve (3), and the second four-way valve (4), respectively, and starts the heating and de-icing mode. The gas-liquid mixture flows out through the tube-side outlet of the second evaporator (14), and enters the condenser (8) through the pipeline and the first solenoid valve (6) for further cooling and liquefaction. Then, the medium-temperature and high-pressure liquid enters the tube-side inlet of the first evaporator (13) through the dryer filter (9), the liquid level indicator (10), and the first electronic expansion valve (11), where it evaporates and absorbs heat, cooling the natural gas from the natural gas heat exchanger (21) from 0 to 5°C to -25 to -30°C. The refrigerant flows back from the tube-side outlet of the first evaporator (13) through the first loop solenoid valve (19) to the air inlet of the low-temperature compressor (1) to achieve refrigerant circulation.

6. The zero-carbon well site associated gas integrated treatment process according to claim 5, characterized in that: in In the case where the first evaporator (13) is used for freezing and the second evaporator (14) is used for pre-cooling, the following applies: After the second evaporator (14) finishes heating and defrosting, instead of directly controlling the function switch between the first evaporator (13) and the second evaporator (14), the second electronic expansion valve (12) is opened slightly to inject a small amount of refrigerant into it. Before the natural gas enters the shell side of the second evaporator (14), the second evaporator (14) is pre-cooled to avoid the natural gas output from the shell side of the second evaporator (14) being substandard due to direct switching. During this period, the high-temperature and high-pressure refrigerant gas compressed by the cryogenic compressor (1) passes through the oil separator (2), the first four-way valve (3), and the second four-way valve (4) to enter the condenser (8) to cool and liquefy into a medium-temperature and high-pressure refrigerant liquid. Then, it passes through the dryer filter (9), and then through the first electronic expansion valve (11) and the second electronic expansion valve (12) to form a low-temperature and low-pressure refrigerant gas. It enters the first evaporator (13) and the second evaporator (14) to freeze the first evaporator (13). The second evaporator (14) is pre-cooled by opening the second electronic expansion valve (12) by a small amount. Finally, the low-temperature and low-pressure refrigerant gas flows from the tube outlet of the first evaporator (13) and the second evaporator (14) to the inlet of the cryogenic compressor (1) to realize the circulation of refrigerant.

7. The zero-carbon well site associated gas integrated treatment process according to claim 6, characterized in that: in In the case where the first evaporator (13) heats and melts ice, and the second evaporator (14) freezes ice, the following applies: When the first evaporator (13) has been in a long-term freezing condition, and the outer wall of the heat exchange coil forms a layer of frost and ice that affects the freezing efficiency, the first evaporator (13) and the second evaporator (14) are switched. At this time, the natural gas proportional regulation electric three-way valve (18) is gradually switched to the natural gas heat exchanger (21) to connect to the second evaporator (14) and to close the connection with the first evaporator (13). Then, the high-temperature and high-pressure refrigerant gas compressed by the low-temperature compressor (1) enters the first evaporator (13) through the oil separator (2), the first four-way valve (3) and the third four-way valve (5), respectively, and starts the de-icing mode. The high-temperature and high-pressure gas-liquid mixture flowing out of the first evaporator (13) enters the condenser (8) through the second solenoid valve (7), and is further cooled and liquefied to form a medium-temperature and high-pressure refrigerant liquid. Then, it passes through the dryer filter (9) and the second electronic expansion valve (12) to form a low-temperature and low-pressure refrigerant gas, which enters the second evaporator (14) to evaporate and absorb heat, cooling the natural gas from the natural gas heat exchanger (21) from 0 to 5°C to -25 to -30°C. The low-temperature and low-pressure refrigerant gas flows back from the tube outlet of the second evaporator (14) through the second loop solenoid valve (20) to the inlet of the low-temperature compressor (1) to realize the circulation of refrigerant.

8. The zero-carbon well site associated gas integrated treatment process according to claim 7, characterized in that: in Under the condition of pre-cooling in the first evaporator (13) and freezing in the second evaporator (14), the following process is included: When ice or frost forms in the second evaporator (14), instead of directly switching the function between the first evaporator (13) and the second evaporator (14), the first electronic expansion valve (11) is opened gradually to inject a small amount of refrigerant into the first evaporator (13). Before the natural gas enters the shell side of the first evaporator (13), the first evaporator (13) is pre-cooled to avoid the sudden switching causing the output natural gas to be substandard. During this period, the high-temperature and high-pressure refrigerant gas compressed by the cryogenic compressor (1) passes through the oil separator (2), the first four-way valve (3) and the third four-way valve (5) respectively and enters the condenser (8) to cool down into a medium-temperature and high-pressure refrigerant liquid. Then it passes through the dryer filter (9), and then through the first electronic expansion valve (11) and the second electronic expansion valve (12) to form a low-temperature and low-pressure refrigerant gas. It enters the first evaporator (13) and the second evaporator (14) respectively to freeze the second evaporator (14). The first evaporator (13) is pre-cooled by opening the first electronic expansion valve (11) by a small amount. Finally, the low-temperature and low-pressure refrigerant gas flows from the tube outlet of the first evaporator (13) and the second evaporator (14) to the inlet of the cryogenic compressor (1) to realize the circulation of refrigerant.

Images