Offshore amine decarburization energy recovery and dense-phase pressurized reinjection technology process package

Abstract

The invention provides an offshore amine decarburization energy recovery and dense-phase pressurized reinjection technical process package. An integrated process is adopted to combine amine decarburization, heat pump pressurization energy recovery and dense-phase reinjection. The method is characterized in that carbon dioxide gas at the top of an absorption tower exchanges heat with amine-rich liquid entering a regeneration tower when being pressurized through a heat pump pipeline, cold energy / heat energy is recovered, and the heat load of the regeneration tower and the cold load of a heat pump system are remarkably reduced; pressurized carbon dioxide is directly treated to be in a dense-phase state through the dense-phase pressurizing pipeline to be reinjected into the stratum, a traditional compressor is replaced, and investment and space are saved. Secondary pregnant solution flash evaporation equipment is arranged, hydrocarbon gas is separated and recycled through primary flash evaporation, primary pregnant solution is treated through secondary flash evaporation, the content and total amount of carbon dioxide in flash evaporation gas are greatly reduced, and hydrocarbon loss is effectively reduced; and the high-carbon-dioxide-content gas of the second-stage flash evaporation is mixed with the carbon dioxide at the top of the regeneration tower and then enters a reinjection process, so that zero carbon emission is realized. Decarburization and reinjection are efficiently integrated, and energy conservation, consumption reduction, emission reduction and economic benefits are considered.

Description

Technical Field

[0001] This invention relates to the field of amine decarbonization technology, and in particular to a process package for energy recovery and dense-phase pressurized reinjection technology for marine amine decarbonization. Background Technology

[0002] As the development scale of offshore oil and gas fields with high carbon dioxide content continues to expand, and to meet the increasingly stringent requirements of downstream markets for product carbon content, amine decarbonization technology, due to its mature and efficient characteristics, is gradually being applied to the process flow of offshore oil and gas production and processing platforms. However, the large-scale application of this technology at sea faces significant challenges.

[0003] First, in conventional processes, the enormous steam consumption required for lean amine regeneration is the main source of energy consumption, directly driving up platform operating costs. With tight energy supply and high costs, the high energy consumption for decarbonization will severely weaken the economic benefits of oil and gas field development. Therefore, there is an urgent need for in-depth optimization of key process parameters such as absorption pressure, lean solution circulation volume, regeneration temperature, and reflux ratio to reduce overall energy consumption.

[0004] Secondly, traditional onshore designs typically treat the amine decarbonization unit as a relatively isolated system for research and optimization, failing to fully consider its close process correlation and complex energy coupling with subsequent key processes (such as natural gas dehydration, light hydrocarbon recovery, liquefaction processes, or reinjection compression systems). This "fragmented" design ignores the cascading effects of decarbonization unit operating conditions (such as regenerated lean amine solution temperature and system pressure) on downstream unit energy consumption, equipment size, and overall process efficiency, resulting in suboptimal overall energy efficiency and failing to fully exploit the synergistic optimization potential of integrated offshore facilities.

[0005] Furthermore, offshore platforms typically maintain high system operating pressures to reduce equipment size and platform footprint. However, under high pressure, the co-absorption effect of the solvent on hydrocarbon components (especially heavy hydrocarbons) is significantly enhanced in traditional amine processes, leading to increased loss of valuable hydrocarbons. This not only reduces product yield and economic efficiency but may also affect the operational stability of subsequent processing units. Simultaneously, during desorption of the high-pressure amine-rich solution in the regeneration tower, achieving the same CO2 desorption rate often requires higher regeneration temperatures or longer residence times. This not only further increases regeneration energy consumption but also results in the CO2 gas emitted from the top of the regeneration tower carrying more volatile organic compounds (VOCs) and trace hydrocarbons generated by solvent degradation, indirectly increasing the total greenhouse gas emissions of the entire process.

[0006] In conclusion, developing an amine-based decarbonization process and system design method that is adapted to the high-pressure offshore environment, has low energy consumption, low hydrocarbon loss, low emissions, and achieves full-process synergistic optimization is of urgent need and great significance for promoting the green and economical development of offshore high-CO2 oil and gas fields. Summary of the Invention

[0007] This invention aims to address at least one of the technical problems existing in the prior art. To this end, this invention provides a process package for energy recovery and dense-phase pressurization reinjection of marine amine decarbonization technology, aiming to solve the problems of high energy consumption in conventional onshore amine decarbonization processes, the traditional onshore process design only studying the amine decarbonization unit as an independent unit and ignoring the process correlation of related subsequent processes, resulting in insufficient optimization of related process design, and the high pressure of marine decarbonization leading to large hydrocarbon loss and CO2 emissions during the regeneration process using traditional amine decarbonization processes.

[0008] This invention provides an amine-based decarbonization system, comprising a decarbonization filter separator, a gas-to-gas heat exchanger, an absorption tower, a purified gas treatment pipeline, a regeneration tower, a lean-rich liquid heat exchanger, a lean liquid pumping pipeline, an amine liquid recovery pipeline, a primary pressure-reducing pipeline, a primary rich liquid flash evaporation device, a secondary pressure-reducing pipeline, a secondary rich liquid flash evaporation device, a carbon dioxide heat pump pipeline, and a carbon dioxide dense-phase pressurization pipeline.

[0009] The inlet of the decarbonization filter separator is used to connect to a high carbon dioxide natural gas source, the liquid phase outlet of the decarbonization filter separator is used to connect to a condensate oil treatment system, the two ends of the first heat exchange channel of the gas-gas heat exchanger are respectively connected to the gas phase outlet of the decarbonization separator and the gas phase inlet of the absorption tower, and the two ends of the second heat exchange channel of the gas-gas heat exchanger are respectively connected to the gas phase outlet of the absorption tower and the purified gas treatment pipeline.

[0010] The liquid phase outlet of the regeneration tower is connected to the inlet of the first heat exchange channel of the lean-rich liquid heat exchanger. The outlet of the first heat exchange channel of the lean-rich liquid heat exchanger is connected to the liquid phase inlet of the absorption tower via the lean liquid pumping pipeline. The lean liquid pumping pipeline is also connected to the amine liquid recovery pipeline. The liquid phase outlet of the absorption tower is connected to the first-stage rich liquid flash evaporator via the first-stage pressure reduction pipeline. The gas phase outlet of the first-stage rich liquid flash evaporator is used to connect to the fuel system. The liquid phase outlet of the first-stage rich liquid flash evaporator is connected to the inlet of the second-stage rich liquid flash evaporator via the second-stage pressure reduction pipeline. The liquid phase outlet of the secondary rich liquid flash evaporator is connected to the inlet of the second heat exchange channel of the lean-rich liquid heat exchanger. The outlet of the second heat exchange channel of the lean-rich liquid heat exchanger is connected to the first heat exchange channel of the carbon dioxide heat pump pipeline. The outlet of the first heat exchange channel of the carbon dioxide heat pump pipeline is connected to the liquid phase inlet of the regeneration tower. The gas phase outlet of the secondary rich liquid flash evaporator and the gas phase outlet of the regeneration tower are both connected to the inlet of the second heat exchange channel of the carbon dioxide heat pump pipeline. The outlet of the second heat exchange channel of the carbon dioxide heat pump pipeline is connected to the wellhead through a carbon dioxide dense phase pressurization pipeline.

[0011] According to the marine amine decarbonization energy recovery and dense phase pressurization reinjection technology package provided by the present invention, the lean liquor pumping pipeline includes a lean liquor booster pump, a lean liquor cooler and a lean liquor booster pump connected in series. The inlet of the lean liquor booster pump is connected to the outlet of the first heat exchange channel of the lean and rich liquor heat exchanger, and the outlet of the lean liquor booster pump is connected to the liquid phase inlet of the absorption tower.

[0012] According to the marine amine decarbonization energy recovery and dense phase pressurization reinjection technology package provided by the present invention, a lean liquid turbine pump is also connected in series on the lean liquid pumping pipeline. The pump body of the lean liquid turbine pump is connected in series between the lean liquid cooler and the liquid phase inlet of the absorption tower, and the turbine of the lean liquid turbine pump is connected between the liquid phase outlet of the absorption tower and the upstream side of the first-stage pressure reduction pipeline.

[0013] According to the offshore amine decarbonization energy recovery and dense phase pressurization reinjection technology package provided by the present invention, the purified gas treatment pipeline includes a purified gas separator. The inlet of the purified gas separator is connected to the gas phase outlet of the absorption tower. The gas phase outlet of the purified gas separator is used to connect to the natural gas dehydration unit. The liquid phase outlet of the purified gas separator is connected to the inlet of the primary rich liquid flash evaporation equipment.

[0014] According to the marine amine decarbonization energy recovery and dense phase pressurization reinjection technology package provided by the present invention, the amine recovery pipeline includes an amine filtration facility skid and a solvent storage tank. The inlet of the amine filtration facility skid is connected between the lean liquid cooler and the lean liquid booster pump in the lean liquid pumping pipeline, and the outlet of the amine filtration facility skid is connected to the solvent storage tank.

[0015] According to the marine amine decarbonization energy recovery and dense-phase pressurized reinjection technology package provided by the present invention, the carbon dioxide heat pump pipeline includes a primary heat pump, a primary heat pump post-heat exchanger, a primary heat pump separator, a secondary heat pump, a secondary heat pump post-heat exchanger, and a secondary heat pump separator. The inlet of the primary heat pump is connected to the gas phase outlet of the secondary rich liquid flash evaporator and the gas phase outlet of the regeneration tower. The outlet of the primary heat pump is connected to the inlet of the second heat exchange channel of the primary heat pump post-heat exchanger. The outlet of the second heat exchange channel of the primary heat pump post-heat exchanger is connected to the inlet of the primary heat pump separator. The gas phase outlet of the primary heat pump separator is connected to the inlet of the secondary heat pump. The outlet of the secondary heat pump is connected to the secondary heat pump separator. The inlet of the second heat exchange channel of the post-pump heat exchanger is connected to the outlet of the second heat exchange channel of the post-secondary heat pump heat exchanger, which is connected to the inlet of the post-secondary heat pump separator. The gas phase outlet of the post-secondary heat pump separator is connected to the dense phase pressurization pipeline. The liquid phase outlets of both the post-first and post-secondary heat pump separators are connected to the liquid phase inlet of the regeneration tower. The inlet of the first heat exchange channel of the post-first heat pump heat exchanger is connected to the outlet of the second heat exchange channel of the lean-rich liquid heat exchanger. The outlet of the first heat exchange channel of the post-first heat pump heat exchanger is connected to the inlet of the first heat exchange channel of the post-secondary heat pump heat exchanger. The outlet of the first heat exchange channel of the post-secondary heat pump heat exchanger is connected to the liquid phase inlet of the regeneration tower.

[0016] According to the marine amine decarbonization energy recovery and dense phase pressurization reinjection technology package provided by the present invention, the carbon dioxide dense phase pressurization pipeline includes a secondary heat pump aftercooler, a secondary heat pump afterwash tank, a carbon dioxide pressurization compressor skid, a molecular sieve dehydration skid, a lithium bromide cooler, a buffer tank, and a carbon dioxide reinjection pump connected in series. The inlet of the secondary heat pump aftercooler is connected to the gas phase outlet of the secondary heat pump separator, and the outlet of the carbon dioxide reinjection pump is used to connect to the wellhead.

[0017] According to the marine amine decarbonization energy recovery and dense phase pressurization reinjection technology package provided by the present invention, a first-stage throttling valve is provided on the first-stage throttling pipeline, and the first-stage throttling valve is used to throttle the rich liquid to 2000 kPa.

[0018] According to the marine amine decarbonization energy recovery and dense phase pressurization reinjection technology package provided by the present invention, a secondary throttling valve is provided on the secondary throttling pipeline, and the secondary throttling valve is used to throttle the rich liquid to 600 kPa.

[0019] The present invention has the following advantages due to the adoption of the above technical solutions:

[0020] This invention provides a marine amine-based decarbonization energy recovery and dense-phase pressurization reinjection technology package. It employs an integrated process for marine amine-based decarbonization and pressurization reinjection, achieving decarbonization, heat pump pressurization energy recovery, and dehydration followed by cooling and dense-phase reinjection. This invention comprehensively considers the marine decarbonization and reinjection pressurization processes. While the top gas from the absorber is pressurized using a carbon dioxide heat pump pipeline, it exchanges heat with the inlet stream of the regeneration tower, achieving energy recovery and reducing the regeneration heat load and the heat pump system's cooling load. The pressurized carbon dioxide is processed into a dense phase using a carbon dioxide dense-phase pressurization pipeline and then reinjected back into the formation, saving the high investment and large footprint problems of traditional carbon dioxide reinjection compressors. A two-stage rich-liquid flash evaporation device is installed to solve the problems of high carbon dioxide content and large flash vapor volume caused by traditional single-stage flash evaporation, which cannot be consumed by the fuel gas system, thus significantly reducing hydrocarbon loss. The high-carbon dioxide gas from the gas phase outlet of the two-stage rich-liquid flash evaporation device and the carbon dioxide gas discharged from the top of the regeneration tower are mixed and enter the carbon dioxide reinjection process, achieving zero carbon emissions. Therefore, this invention can be widely applied in the field of CCS technology for high-carbon dioxide associated gas on offshore platforms. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the flash evaporation system process in the marine amine decarbonization energy recovery and dense phase pressurization reinjection technology process package provided in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the regeneration system process in the marine amine decarbonization energy recovery and dense phase pressurized reinjection technology process package provided in an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the carbon dioxide reinjection system process in the marine amine decarbonization energy recovery and dense phase pressurization reinjection technology process package provided in an embodiment of the present invention.

[0025] Figure label:

[0026] 1: Decarbonization filter separator; 2: Gas-gas heat exchanger; 3: Absorber; 4: Lean liquor turbine pump; 5: Lean liquor booster pump; 6: Lean liquor cooler; 7: First-stage rich liquor flash tank; 8: Second-stage rich liquor flash tank; 9: Amine liquid filtration facility skid; 10: Purified gas separator; 11: Lean liquor lift pump; 12: Lean-rich liquor heat exchanger; 13: Regeneration tower; 14: Regeneration tower bottom reboiler; 15: First-stage heat pump; 16: First-stage heat pump post-heat exchanger; 17: First-stage heat pump separator; 18: Second-stage heat pump; 19: Second-stage heat pump post-heat exchanger; 20: Second-stage heat pump separator; 21: Second-stage heat pump post-cooler; 22: Second-stage heat pump post-gas scrubbing tank; 23: Carbon dioxide booster compressor skid; 24: Molecular sieve dehydration skid; 25: Lithium bromide cooler; 26: Buffer tank; 27: Carbon dioxide reinjection pump. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0028] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0030] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0031] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0032] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0033] This invention provides a marine amine-based decarbonization energy recovery and dense-phase pressurization reinjection technology package, comprising a decarbonization filter separator, a gas-to-gas heat exchanger, an absorption tower, purified gas treatment pipelines, a regeneration tower, lean and rich liquid heat exchangers, lean liquid pumping pipelines, amine liquid recovery pipelines, a primary pressure-reducing pipeline, a primary rich liquid flash evaporation device, a secondary pressure-reducing pipeline, a secondary rich liquid flash evaporation device, a carbon dioxide heat pump pipeline, and a carbon dioxide dense-phase pressurization pipeline. This marine amine-based decarbonization energy recovery and dense-phase pressurization reinjection technology package adopts an integrated process for marine amine-based decarbonization and pressurization reinjection, achieving energy recovery through decarbonization and heat pump pressurization, and subsequent cooling and dense-phase reinjection after dehydration. This invention comprehensively considers the marine decarbonization and reinjection pressurization process. While the top gas of the absorption tower is pressurized using the carbon dioxide heat pump pipeline, it exchanges heat with the inlet stream of the regeneration tower, achieving energy recovery and reducing the regeneration heat load and the heat pump system cooling load. The pressurized carbon dioxide is processed into a dense phase using a dense phase pressurization pipeline before being reinjected into the formation, saving the high investment and large footprint problems associated with traditional carbon dioxide reinjection compressors. A two-stage rich-liquid flash evaporation unit is installed to solve the problems of high carbon dioxide content and large flash volume caused by traditional single-stage flash evaporation, which cannot be consumed by the fuel gas system, thus significantly reducing hydrocarbon loss. The high-carbon dioxide gas from the gas phase outlet of the two-stage rich-liquid flash evaporation unit and the carbon dioxide gas discharged from the top of the regeneration tower are mixed and enter the carbon dioxide reinjection process, achieving zero carbon emissions. Therefore, this invention can be widely applied in the field of CCS technology for high-carbon dioxide associated gas on offshore platforms.

[0034] The following combination Figures 1 to 3 This invention describes the marine amine decarbonization energy recovery and dense-phase pressurized reinjection technology process package.

[0035] The embodiments of the present invention provide a process package for marine amine decarbonization energy recovery and dense phase pressurization reinjection technology, including a decarbonization filter separator 1, a gas-to-gas heat exchanger 2, an absorption tower 3, a purified gas treatment pipeline, a regeneration tower 13, a lean and rich liquid heat exchanger 12, a lean liquid pumping pipeline, an amine liquid recovery pipeline, a primary pressure reduction pipeline, a primary rich liquid flash evaporation device, a secondary pressure reduction pipeline, a secondary rich liquid flash evaporation device, a carbon dioxide heat pump pipeline, and a carbon dioxide dense phase pressurization pipeline.

[0036] The connection between the marine amine-based decarbonization energy recovery and dense-phase pressurized reinjection technology package is as follows:

[0037] The inlet of the decarbonization filter separator 1 is connected to a high-carbon dioxide natural gas source, and the liquid phase outlet of the decarbonization filter separator 1 is connected to a condensate oil treatment system. The two ends of the first heat exchange channel of the gas-gas heat exchanger 2 are connected to the gas phase outlet of the decarbonization separator and the gas phase inlet of the absorption tower 3, respectively. The two ends of the second heat exchange channel of the gas-gas heat exchanger 2 are connected to the gas phase outlet of the absorption tower 3 and the purified gas treatment pipeline, respectively. The liquid phase outlet of the regeneration tower 13 is connected to the inlet of the first heat exchange channel of the lean-rich liquid heat exchanger 12. The outlet of the first heat exchange channel of the lean-rich liquid heat exchanger 12 is connected to the liquid phase inlet of the absorption tower 3 via a lean liquid pumping pipeline. The lean liquid pumping pipeline is also connected to an amine recovery pipeline. The liquid phase outlet of the absorption tower 3 is connected to the first-stage rich liquid flash evaporator via a first-stage pressure reduction pipeline. The gas phase outlet of the first-stage rich liquid flash evaporator is connected to a fuel system. The liquid phase outlet of the first-stage rich liquid flash evaporator is connected to the inlet of the second-stage rich liquid flash evaporator via a second-stage pressure reduction pipeline. The liquid phase outlet of the evaporation equipment is connected to the inlet of the second heat exchange channel of the lean-rich liquid heat exchanger 12. The outlet of the second heat exchange channel of the lean-rich liquid heat exchanger 12 is connected to the first heat exchange channel of the carbon dioxide heat pump pipeline. The outlet of the first heat exchange channel of the carbon dioxide heat pump pipeline is connected to the liquid phase inlet of the regeneration tower 13. The gas phase outlet of the secondary rich liquid flash evaporation equipment and the gas phase outlet of the regeneration tower 13 are both connected to the inlet of the second heat exchange channel of the carbon dioxide heat pump pipeline. The outlet of the second heat exchange channel of the carbon dioxide heat pump pipeline is connected to the wellhead through a carbon dioxide dense phase pressurization pipeline.

[0038] Natural gas with a CO2 content of approximately 34% from the gas phase outlet of the upstream sluice trap enters the decarbonization filter separator 1. The separated liquid phase goes to the condensate oil treatment system through the liquid phase outlet, while the gas phase enters the first heat exchange channel of the gas-gas heat exchanger 2. After heat exchange, it enters the absorption tower 3 through the gas phase inlet.

[0039] The liquid phase inlet of the absorption tower 3 is used to receive the lean amine liquid from the regeneration tower 13. Inside the absorption tower 3, the lean amine liquid processes the gas phase from the first heat exchange channel of the gas-gas heat exchanger 2 into purified gas with a CO2 content of 3%. The purified gas is discharged through the gas phase outlet at the top of the tower and enters the second heat exchange channel of the gas-gas heat exchanger 2. After exchanging heat with the fluid in the first heat exchange channel, the purified gas is cooled and processed in the pipeline.

[0040] The primary rich liquid flash evaporation equipment can be a primary rich liquid flash evaporator 7, and the secondary rich liquid flash evaporation equipment can be a secondary rich liquid flash evaporator 8.

[0041] The high-pressure rich liquid separated from the absorber 3 is discharged through the liquid phase outlet of the absorber 3, and then the pressure is reduced from 9000 kPa to 2000 kPa through the first-stage pressure reduction pipeline before being discharged into the first-stage rich liquid flash tank 7. The gas phase flashed out of the first-stage rich liquid flash tank 7 enters the fuel gas system for user use, and the liquid phase is then reduced to 600 kPa through the second-stage throttling pipeline before entering the second-stage rich liquid flash tank 8. In this way, the gas phase hydrocarbon content of the second-stage rich liquid flash tank 8 can be reduced.

[0042] The high-temperature liquid phase separated by the secondary rich liquid flash tank 8 enters the inlet of the second heat exchange channel of the lean-rich liquid heat exchanger 12, and then enters the first heat exchange channel of the carbon dioxide heat pump pipeline through the outlet of the second heat exchange channel of the lean-rich liquid heat exchanger 12. The lean amine liquid discharged from the liquid phase outlet of the regeneration tower 13 enters the inlet of the first heat exchange channel of the lean-rich liquid heat exchanger 12, and then is discharged to the absorption tower 3 through the outlet of the first heat exchange channel of the lean-rich liquid heat exchanger 12. It can be seen that when the lean amine liquid discharged from the liquid phase outlet of the regeneration tower 13 passes through the first heat exchange channel of the lean-rich liquid heat exchanger 12, it exchanges heat with the high-temperature liquid phase separated by the secondary rich liquid flash tank 8 in the second heat exchange channel of the lean-rich liquid heat exchanger 12 to raise its temperature, thus utilizing the waste heat of the high-temperature liquid phase separated by the secondary rich liquid flash tank 8.

[0043] The rich liquid from the secondary rich liquid flash tank 8 and the lean amine liquid from the bottom of the regeneration tower 13 exchange heat through the lean-rich liquid heat exchanger 12, and then enter the inlet of the first heat exchange channel of the carbon dioxide heat pump pipeline. The liquid then returns to the regeneration tower 13 through the outlet of the first heat exchange channel. The carbon dioxide gas obtained from the regeneration tower 13 and the gas from the gas phase outlet of the secondary rich liquid flash tank 8 enter the second heat exchange channel of the carbon dioxide heat pump pipeline. The gas then enters the carbon dioxide dense phase pressurization pipeline through the outlet of the second heat exchange channel, and finally is reinjected into the carbon dioxide reinjection well.

[0044] In the carbon dioxide heat pump pipeline, the rich liquid from the secondary rich liquid flash tank 8 exchanges heat with the carbon dioxide gas from the regeneration tower 13 and the gas from the gas phase outlet of the secondary rich liquid flash tank 8 to raise its temperature. Finally, it enters the regeneration tower 13, which can reduce the heat load of the reboiler.

[0045] Meanwhile, the CO2 gas from the top of the regeneration tower 13 exchanges heat with the gas phase from the secondary rich liquid flash tank 8 to reduce the cooling load after the heat pump and realize energy recovery.

[0046] In some embodiments, the lean liquor pumping pipeline includes a lean liquor booster pump 11, a lean liquor cooler 6, and a lean liquor booster pump 5. The inlet end of the lean liquor booster pump 11 is connected to the outlet of the first heat exchange channel of the lean-rich liquor heat exchanger 12, the inlet end of the lean liquor cooler 6 is connected to the outlet end of the lean liquor booster pump 11, the inlet end of the lean liquor booster pump 5 is connected to the outlet end of the lean liquor cooler 6, and the outlet end of the lean liquor booster pump 5 is connected to the liquid phase inlet of the absorption tower 3.

[0047] In some embodiments, a lean liquid turbine pump 4 is connected in series in the lean liquid pumping pipeline. The inlet end of the lean liquid turbine pump 4 is connected to the outlet of the lean liquid cooler 6, and the outlet end of the lean liquid turbine pump 4 is connected to the liquid phase inlet of the absorption tower 3. The turbine of the lean liquid turbine pump 4 is connected between the liquid phase outlet of the absorption tower 3 and the upstream side of the primary pressure reduction pipeline.

[0048] In this way, the lean liquid turbine pump 4 replaces the traditional pressure regulating valve, and uses the pressure of the rich liquid at the bottom of the absorption tower 3 to drive the lean liquid turbine pump 4 to rotate, converting pressure energy into mechanical energy and recovering the pressure energy of the rich liquid at the bottom of the tower.

[0049] In some embodiments, the purified gas treatment pipeline includes a purified gas separator 10, the inlet of which is connected to the outlet of the second heat exchange channel of the gas-gas heat exchanger 2, the gas phase outlet of the purified gas separator 10 is used to connect to the natural gas dehydration unit, and the liquid phase outlet of the purified gas separator 10 is connected to the inlet of the primary rich liquid flash tank 7.

[0050] In some embodiments, the amine recovery pipeline includes an amine filtration skid 9 and a solvent storage tank. The inlet of the amine filtration skid 9 is connected to the pipeline between the lean liquid cooler 6 and the lean liquid booster pump 5, and the solvent storage tank is connected to the outlet of the amine filtration skid 9. The lean amine solution from the regeneration tower 13 passes through the lean-rich liquid heat exchanger 12 and the lean liquid booster pump 11, then through the lean liquid cooler 6. Part of it enters the absorption tower 3 through the lean liquid booster pump 5, and the other part is filtered through the amine filtration skid 9 and then enters the solvent storage tank.

[0051] In some embodiments, the carbon dioxide heat pump pipeline includes a primary heat pump 15, a primary heat pump downstream heat exchanger 16, a primary heat pump separator 17, a secondary heat pump 18, a secondary heat pump downstream heat exchanger 19, and a secondary heat pump separator 20. The inlet of the primary heat pump 15 is connected to the vapor phase outlet of the secondary rich liquid flash evaporator and the vapor phase outlet of the regeneration tower 13. The outlet of the primary heat pump 15 is connected to the inlet of the second heat exchange channel of the primary heat pump downstream heat exchanger 16. The outlet of the second heat exchange channel of the primary heat pump downstream heat exchanger 16 is connected to the inlet of the primary heat pump separator 17. The vapor phase outlet of the primary heat pump separator 17 is connected to the inlet of the secondary heat pump 18. The outlet of the secondary heat pump 18 is connected to the second heat exchange channel of the secondary heat pump downstream heat exchanger 19. The outlet of the second heat exchange channel of the secondary heat pump post-heat exchanger 19 is connected to the inlet of the secondary heat pump separator 20. The gas phase outlet of the secondary heat pump separator 20 is connected to the dense phase pressurization pipeline. The liquid phase outlets of the primary heat pump separator 17 and the secondary heat pump separator 20 are both connected to the liquid phase inlet of the regeneration tower 13. The inlet of the first heat exchange channel of the primary heat pump post-heat exchanger 16 is connected to the outlet of the second heat exchange channel of the lean and rich liquid heat exchanger 12. The outlet of the first heat exchange channel of the primary heat pump post-heat exchanger 16 is connected to the inlet of the first heat exchange channel of the secondary heat pump post-heat exchanger 19. The outlet of the first heat exchange channel of the secondary heat pump post-heat exchanger 19 is connected to the liquid phase inlet of the regeneration tower 13 through the lean liquid pumping pipeline.

[0052] The gas discharged from the vapor phase outlet of the secondary rich liquid flash evaporator and the gas discharged from the vapor phase outlet of the regeneration tower 13 are both pressurized by the primary heat pump 15 and then enter the second heat exchange channel of the heat exchanger 16 after the primary heat pump. There, they exchange heat with the rich liquid from the second heat exchange channel of the lean-rich liquid heat exchanger 12, which enters the first heat exchange channel of the heat exchanger 16 after the primary heat pump, thus heating the rich liquid from the lean-rich liquid heat exchanger 12. After heating, the rich liquid returns to the regeneration tower 13. The gas discharged from the vapor phase outlet of the secondary rich liquid flash evaporator and the gas discharged from the vapor phase outlet of the regeneration tower 13 enter the primary heat pump separator 17 after passing through the second heat exchange channel of the heat exchanger 16 after the primary heat pump. The separated gas phase enters the secondary heat pump 18, and the separated liquid phase returns to the regeneration tower 13 through the liquid phase inlet.

[0053] The gas phase discharged from the gas phase outlet of the primary heat pump separator 17 is pressurized by the secondary heat pump 18 and enters the second heat exchange channel of the secondary heat pump post-heat exchanger 19. It exchanges heat with the rich liquid from the second heat exchange channel of the lean-rich liquid heat exchanger 12, which enters the first heat exchange channel of the secondary heat pump post-heat exchanger 19, thus heating the rich liquid from the lean-rich liquid heat exchanger 12. After heating, the rich liquid returns to the regeneration tower 13. The gas phase discharged from the gas phase outlet of the primary heat pump separator 17 enters the secondary heat pump separator 20 after passing through the second heat exchange channel of the secondary heat pump post-heat exchanger 19. The separated gas phase enters the dense phase pressurization pipeline for pressurization and is then reinjected into the CO2 reinjection well. The separated liquid phase returns to the regeneration tower 13 through the liquid phase inlet.

[0054] The carbon dioxide gas discharged from the gas phase outlet of the regeneration tower 13 does not need to be cooled and is directly connected to the inlet of the first-stage heat pump 15 at high temperature. This can make full use of the heat of the top gas of the regeneration tower 13 and save the top cooler and reflux tank.

[0055] Before entering the regeneration tower 13, the rich liquid first passes through the second heat exchange channel of the first-stage heat pump after heat exchanger 16 and the second-stage heat pump after heat exchanger 19 to exchange heat and raise its temperature, thereby reducing the load on the reboiler 14 of the regeneration tower and saving the heat pump after cooler.

[0056] In some embodiments, the carbon dioxide dense-phase pressurization pipeline includes a secondary heat pump aftercooler 21, a secondary heat pump afterwash tank 22, a carbon dioxide booster compressor skid 23, a molecular sieve dehydration skid 24, a lithium bromide cooler 25, a buffer tank 26, and a carbon dioxide reinjection pump 27. The inlet of the secondary heat pump aftercooler 21 is connected to the gas phase outlet of the secondary heat pump separator 20, and cooling water is used to cool the carbon dioxide gas. The inlet of the secondary heat pump afterwash tank 22 is connected to the gas phase outlet of the secondary heat pump aftercooler 21. The inlet of the carbon dioxide booster compressor skid 23 is connected to the outlet of the secondary heat pump post-wash tank 22; the inlet of the molecular sieve dehydration skid 24 is connected to the outlet of the carbon dioxide booster compressor skid; the inlet of the lithium bromide cooler 25 is connected to the outlet of the molecular sieve dehydration skid 24; the inlet of the buffer tank 26 is connected to the outlet of the lithium bromide cooler 25; the inlet of the carbon dioxide reinjection pump 27 is connected to the outlet of the buffer tank 26; and the outlet of the carbon dioxide reinjection pump 27 is connected to the wellhead of the CO2 reinjection well.

[0057] The carbon dioxide heat pump pipeline is pressurized by the heat pump, and after the CO2 gas is cooled and washed, it is pressurized to 5200 kPa by the carbon dioxide booster compressor skid 23 and then enters the molecular sieve dehydration skid 24 to be dehydrated to 200 ppm. After that, it enters the lithium bromide cooler 25 to be cooled to 15°C to the dense phase. After passing through the buffer tank 26, it is pressurized by the carbon dioxide reinjection pump 27 and reinjected into the CO2 reinjection well.

[0058] The lithium bromide cooler 25 cools gaseous carbon dioxide to a liquid state with a temperature not exceeding 10°C, preferably not exceeding 15°C, and a pressure below the critical pressure, thereby reducing the energy consumption of the pressurization and reinjection system. The lithium bromide cooler 25 uses lithium bromide-water, ammonia-water, or other suitable working fluid pairs as the refrigerant.

[0059] This dense-phase carbon dioxide booster line can handle dense-phase carbon dioxide fluids near or above the critical pressure. Buffer tank 26 is used to stabilize the flow rate and pressure of dense-phase carbon dioxide.

[0060] In some embodiments, a primary throttling valve is installed on the primary throttling pipeline, which can reduce the pressure of the rich liquid from approximately 9000 kPa to at least 2000 kPa. A secondary throttling valve is installed on the secondary throttling pipeline, which can reduce the pressure of the rich liquid from at least 2000 kPa to at least 600 kPa. This reduces the gaseous hydrocarbon content in the secondary rich liquid flash evaporation equipment.

[0061] It should be noted that the pressure reduction range of the primary throttle valve is determined by user requirements, and the 2000 kPa mentioned here is merely an illustrative example and does not limit the scope of protection of this invention. Similarly, the pressure reduction range of the secondary throttle valve is also determined by user requirements, and the 600 kPa mentioned here is also merely an illustrative example and does not limit the scope of protection of this invention.

[0062] The marine amine decarbonization energy recovery and dense phase pressurized reinjection technology package provided by this invention achieves zero carbon emissions in the decarbonization process of associated gas with high CO2 content on offshore platforms.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A process package for marine amine-based decarbonization energy recovery and dense-phase pressurized reinjection technology, characterized in that, It includes a decarbonization filter separator (1), a gas-gas heat exchanger (2), an absorption tower (3), a purified gas treatment pipeline, a regeneration tower (13), a lean and rich liquid heat exchanger (12), a lean liquid pumping pipeline, an amine liquid recovery pipeline, a primary pressure reduction pipeline, a primary rich liquid flash evaporation device, a secondary pressure reduction pipeline, a secondary rich liquid flash evaporation device, a carbon dioxide heat pump pipeline, and a carbon dioxide dense phase pressurization pipeline. The inlet of the decarbonization filter separator (1) is used to connect to a natural gas source with high carbon dioxide content, the liquid phase outlet of the decarbonization filter separator (1) is used to connect to a condensate oil treatment system, the two ends of the first heat exchange channel of the gas-gas heat exchanger (2) are respectively connected to the gas phase outlet of the decarbonization separator and the gas phase inlet of the absorption tower (3), and the two ends of the second heat exchange channel of the gas-gas heat exchanger (2) are respectively connected to the gas phase outlet of the absorption tower (3) and the purified gas treatment pipeline. The liquid phase outlet of the regeneration tower (13) is connected to the inlet of the first heat exchange channel of the lean-rich liquid heat exchanger (12). The outlet of the first heat exchange channel of the lean-rich liquid heat exchanger (12) is connected to the liquid phase inlet of the absorption tower (3) through the lean liquid pumping pipeline. The lean liquid pumping pipeline is also connected to the amine liquid recovery pipeline. The liquid phase outlet of the absorption tower (3) is connected to the first-stage rich liquid flash evaporator through the first-stage pressure reduction pipeline. The gas phase outlet of the first-stage rich liquid flash evaporator is used to connect to the fuel system. The liquid phase outlet of the first-stage rich liquid flash evaporator is connected to the inlet of the second-stage rich liquid flash evaporator through the second-stage pressure reduction pipeline. The liquid phase outlet of the secondary rich liquid flash evaporator is connected to the inlet of the second heat exchange channel of the rich-lean liquid heat exchanger (12). The outlet of the second heat exchange channel of the rich-lean liquid heat exchanger (12) is connected to the first heat exchange channel of the carbon dioxide heat pump pipeline. The outlet of the first heat exchange channel of the carbon dioxide heat pump pipeline is connected to the liquid phase inlet of the regeneration tower (13). The gas phase outlet of the secondary rich liquid flash evaporator and the gas phase outlet of the regeneration tower (13) are both connected to the inlet of the second heat exchange channel of the carbon dioxide heat pump pipeline. The outlet of the second heat exchange channel of the carbon dioxide heat pump pipeline is connected to the wellhead through a carbon dioxide dense phase pressurization pipeline.

2. The marine amine decarbonization energy recovery and dense-phase pressurization reinjection technology package according to claim 1, characterized in that, The lean liquid pumping pipeline includes a lean liquid booster pump (11), a lean liquid cooler (6), and a lean liquid booster pump (5) connected in series. The inlet of the lean liquid booster pump (11) is connected to the outlet of the first heat exchange channel of the lean-rich liquid heat exchanger (12), and the outlet of the lean liquid booster pump (5) is connected to the liquid phase inlet of the absorption tower (3).

3. The marine amine decarbonization energy recovery and dense-phase pressurization reinjection technology package according to claim 2, characterized in that, A lean liquid turbine pump (4) is also connected in series on the lean liquid pumping pipeline. The pump body of the lean liquid turbine pump (4) is connected in series between the lean liquid cooler (6) and the liquid phase inlet of the absorption tower (3). The turbine of the lean liquid turbine pump (4) is connected between the liquid phase outlet of the absorption tower (3) and the upstream side of the primary pressure reduction pipeline.

4. The marine amine decarbonization energy recovery and dense-phase pressurization reinjection technology package according to claim 1, characterized in that, The purified gas treatment pipeline includes a purified gas separator (10), the inlet of which is connected to the gas phase outlet of the absorption tower (3), the gas phase outlet of which is connected to the natural gas dehydration unit, and the liquid phase outlet of which is connected to the inlet of the primary rich liquid flash evaporation equipment.

5. The marine amine decarbonization energy recovery and dense-phase pressurization reinjection technology package according to claim 2, characterized in that, The amine recovery pipeline includes an amine filtration facility skid and a solvent storage tank. The inlet of the amine filtration facility skid (9) is connected between the lean liquid cooler (6) and the lean liquid booster pump (5) in the lean liquid pumping pipeline, and the outlet of the amine filtration facility skid (9) is connected to the solvent storage tank.

6. The marine amine decarbonization energy recovery and dense-phase pressurization reinjection technology package according to claim 1, characterized in that, The carbon dioxide heat pump pipeline includes a primary heat pump (15), a primary heat pump downstream heat exchanger (16), a primary heat pump distribution tank (17), a secondary heat pump (18), a secondary heat pump downstream heat exchanger (19), and a secondary heat pump distribution tank (20). The inlet of the primary heat pump (15) is connected to the gas phase outlet of the secondary rich liquid flash evaporator and the gas phase outlet of the regeneration tower (13). The outlet of the primary heat pump (15) is connected to the inlet of the second heat exchange channel of the primary heat pump downstream heat exchanger (16). The outlet of the second heat exchange channel of the primary heat pump downstream heat exchanger (16) is connected to the inlet of the primary heat pump distribution tank (17). The gas phase outlet of the primary heat pump distribution tank (17) is connected to the inlet of the secondary heat pump (18). The outlet of the secondary heat pump (18) is connected to the inlet of the second heat exchange channel of the secondary heat pump downstream heat exchanger (19). The inlet of the two heat exchange channels is connected, the outlet of the second heat exchange channel of the secondary heat pump post-heat exchanger (19) is connected to the inlet of the secondary heat pump separator (20), the gas phase outlet of the secondary heat pump separator (20) is connected to the dense phase pressurization pipeline, the liquid phase outlets of the primary heat pump separator (17) and the secondary heat pump separator (20) are both connected to the liquid phase inlet of the regeneration tower (13), the inlet of the first heat exchange channel of the primary heat pump post-heat exchanger (16) is connected to the outlet of the second heat exchange channel of the lean and rich liquid heat exchanger (12), the outlet of the first heat exchange channel of the primary heat pump post-heat exchanger (16) is connected to the inlet of the first heat exchange channel of the secondary heat pump post-heat exchanger (19), and the outlet of the first heat exchange channel of the secondary heat pump post-heat exchanger (19) is connected to the liquid phase inlet of the regeneration tower (13).

7. The marine amine decarbonization energy recovery and dense-phase pressurization reinjection technology package according to claim 6, characterized in that, The carbon dioxide dense-phase pressurization pipeline includes a secondary heat pump aftercooler (21), a secondary heat pump afterwash tank (22), a carbon dioxide pressurization compressor skid (23), a molecular sieve dehydration skid (24), a lithium bromide cooler (25), a buffer tank (26), and a carbon dioxide reinjection pump (27) connected in series. The inlet of the secondary heat pump aftercooler (21) is connected to the gas phase outlet of the secondary heat pump separator (20), and the outlet of the carbon dioxide reinjection pump (27) is used to connect to the reinjection subsea pipeline or wellhead.

8. The marine amine decarbonization energy recovery and dense-phase pressurization reinjection technology package according to claim 1, characterized in that, The primary throttling pipeline is equipped with a primary throttling valve, which is used to throttle the rich liquid to at least 2000 kPa.

9. The marine amine decarbonization energy recovery and dense-phase pressurization reinjection technology package according to claim 1, characterized in that, The secondary throttling pipeline is equipped with a secondary throttling valve, which is used to throttle the rich liquid to at least 600 kPa.

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