Liquid carbon dioxide injection pump

Abstract

The utility model discloses a liquid carbon dioxide injection pump, and belongs to the technical field of injection pumps, and the liquid carbon dioxide injection pump comprises a pressurizing assembly used for pressurizing input liquid carbon dioxide. The plunger assembly comprises a plunger body, a plunger shell, first sealing filler and second sealing filler, a containing cavity is defined by the plunger shell, the plunger body is located in the containing cavity and comprises a first sub-plunger and a second sub-plunger which are connected, and the cross section area of the first sub-plunger is larger than that of the second sub-plunger; a flow channel is formed between the second sub-plunger and the plunger shell, the first sealing filler is clamped between the first sub-plunger and the plunger shell, and the second sealing filler is clamped between the second sub-plunger and the plunger shell. The liquid carbon dioxide can take away heat along the flow channel, impurities or solid dry ice on the surface of the plunger body are washed away, the pressing force of the first sealing filler and the friction force between the first sealing filler and the first sub-plunger can be reduced, and the service life of the plunger assembly is effectively prolonged.

Description

Technical Field

[0001] This application belongs to the technical field of injection pumps, and particularly relates to a liquid carbon dioxide injection pump. Background Art

[0002] Carbon dioxide capture, utilization, and storage technology is an important means to reduce carbon dioxide emissions, ensure energy security, and achieve sustainable development. The current main method is to inject liquid carbon dioxide underground through a carbon dioxide injection pump. The carbon dioxide can flow into the micro-pores of the formation and dissolve in the crude oil, reducing the viscosity of the crude oil and expanding its volume, thereby reducing the difficulty of crude oil extraction and increasing the production volume to achieve the purpose of improving the crude oil recovery rate. At the same time, during the carbon dioxide flooding process, a part of the carbon dioxide will be sealed in the formation, achieving carbon dioxide emission reduction while improving the recovery rate. Liquid carbon dioxide injection pumps operate under high pressure and low temperature conditions. Coupled with the characteristics of liquid carbon dioxide, it will rapidly expand and gasify when absorbing heat or reducing pressure, and produce very hard low-temperature carbon dioxide solid dry ice and ice cubes. To prevent carbon dioxide leakage, the pressing force between the packing and the plunger will be very large. Due to friction, the liquid carbon dioxide gasifies on the working surface of the plunger and forms solid dry ice. Such a complex and harsh working environment is more likely to wear the packing and the plunger, resulting in a larger leakage volume, forming more solid dry ice on the plunger surface, and continuously causing a vicious cycle of working conditions. Currently, it is usually adopted to improve the materials of the plunger and the packing, or reduce the friction coefficient between the plunger and the packing to increase the service life of the plunger, but the actual effect is not good. Summary of the Utility Model

[0003] Purpose of the Utility Model: The embodiments of this application provide a liquid carbon dioxide injection pump, aiming to solve the technical problem of the short service life of the plunger caused by liquid carbon dioxide leakage.

[0004] Technical Solution: A liquid carbon dioxide injection pump according to the embodiments of this application includes:

[0005] A boosting assembly for boosting the input liquid carbon dioxide;

[0006] A plunger assembly including a plunger body, a plunger housing, a first sealing packing, and a second sealing packing. The plunger housing encloses a receiving cavity. The plunger body is located in the receiving cavity. The plunger body includes a first sub-plunger and a second sub-plunger connected to each other. The cross-sectional area of the first sub-plunger is larger than that of the second sub-plunger. A flow channel is formed between the second sub-plunger and the plunger housing. The first sealing packing is clamped between the first sub-plunger and the plunger housing, and the second sealing packing is clamped between the second sub-plunger and the plunger housing;

[0007] A first pipeline connecting the boosting assembly and the plunger assembly for inputting the boosted liquid carbon dioxide into the flow channel;

[0008] A second pipeline, which is communicated with the plunger assembly and is used for discharging the liquid carbon dioxide in the flow channel.

[0009] In some embodiments, the plunger housing includes a first housing and a second housing. The first housing is connected to the first sub-plunger, the second housing is connected to the second sub-plunger, a flow channel is formed between the second housing and the second sub-plunger, and at least a part of the first housing overlaps the outer periphery of the second housing.

[0010] In some embodiments, a first sealing packing is clamped between the first sub-plunger and the first housing; a second sealing packing is clamped between the second sub-plunger and the second housing.

[0011] In some embodiments, the plunger housing further includes:

[0012] A first adjusting member, which is arranged at the connection of the first housing and the second housing and is respectively connected to the first housing and the second housing;

[0013] A second adjusting member, which is arranged at one end of the second housing far from the first housing and is respectively connected to the second sub-plunger and the second housing.

[0014] In some embodiments, the plunger assembly includes a first seal, and the first seal is clamped between the first housing and the second housing.

[0015] In some embodiments, the boosting assembly has a first inlet and a first outlet, the plunger housing has a second inlet and a second outlet, the second inlet and the second outlet are respectively communicated with the flow channel, a first pipeline communicates the first outlet and the second inlet, and a second pipeline communicates the first inlet and the second outlet.

[0016] In some embodiments, the boosting assembly further includes a boosting flow channel and a plurality of one-way valves arranged on the boosting flow channel, and the boosting flow channel is communicated with the accommodating cavity.

[0017] In some embodiments, the one-way valve includes a first valve seat, a second valve seat and a ball valve. The first valve seat has a guiding hole, the second valve seat has a liquid discharge hole, a containing space is formed by enclosing the first valve seat and the second valve seat, and the ball valve is located in the containing space and is movably arranged in the guiding hole.

[0018] In some embodiments, the one-way valve includes a second seal, and the second seal is clamped between the first valve seat and the second valve seat.

[0019] In some embodiments, the number of the plunger assemblies is multiple, each plunger assembly is correspondingly provided with a first pipeline and a second pipeline, and the multiple plunger assemblies are connected in parallel to the boosting assembly.

[0020] Beneficial effects: The present application provides a liquid carbon dioxide injection pump, comprising a boosting assembly, a plunger assembly, a first pipeline and a second pipeline, wherein the boosting assembly is used to boost the input liquid carbon dioxide. The plunger assembly comprises a plunger body, a plunger shell, a first sealing filler and a second sealing filler, the plunger shell is enclosed to form a receiving chamber, the plunger body is located in the receiving chamber, the plunger body comprises a first sub-plunger and a second sub-plunger connected to each other, the cross-sectional area of ​​the first sub-plunger is greater than the cross-sectional area of ​​the second sub-plunger, a flow channel is formed between the second sub-plunger and the plunger shell, the first sealing filler is sandwiched between the first sub-plunger and the plunger shell, and the second sealing filler is sandwiched between the second sub-plunger and the plunger shell; the first pipeline is used to input the pressurized liquid carbon dioxide into the flow channel. The second pipeline is connected to the plunger assembly, and the second pipeline is used to discharge the liquid carbon dioxide in the flow channel. By setting a second sub-plunger with a smaller cross-sectional area to form a flow channel with the plunger shell, the pressurized liquid carbon dioxide can take away part of the heat along the flow channel and flush out impurities or solid dry ice on the surface of the plunger body. In addition, the pressing force of the first sealing filler and the friction between the first sealing filler and the first sub-plunger can be reduced, thereby effectively extending the service life of the first sealing filler and the first sub-plunger. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 is a schematic diagram of a liquid carbon dioxide injection pump according to an embodiment of the present application;

[0023] Figure 2 It is a structural schematic diagram of a plunger body in an embodiment of the present application;

[0024] Figure 3 is a cross-sectional view of a liquid carbon dioxide injection pump according to an embodiment of the present application;

[0025] Figure 4 yes Figure 3 A magnified view of part A;

[0026] Figure 5 yes Figure 3 A magnified view of part B;

[0027] Figure 6 It is a schematic structural diagram of a liquid carbon dioxide injection pump according to an embodiment of the present application.

[0028] Reference numerals: 1, supercharging assembly; 2, plunger assembly; 3, first pipeline; 4, second pipeline; 5, driving member; 10, first inlet; 11, first outlet; 12, supercharging flow channel; 13, one-way valve; 20, plunger body; 21, plunger housing; 22, first sealing packing; 23, second sealing packing; 24, accommodating cavity; 25, first seal; 130, first valve seat; 131, second valve seat; 132, ball valve; 133, accommodating space; 134, second seal; 200, first sub-plunger; 201, second sub-plunger; 202, flow channel; 210, first housing; 211, second housing; 212, first adjusting member; 213, second adjusting member; 214, second inlet; 215, second outlet; 1300, guiding hole; 1310, liquid discharge hole. Detailed implementation manners

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present application.

[0030] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present application. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "a plurality of" means two or more, and "at least one" means one, two or more, unless otherwise specifically defined. In the description of the present application, "vertical" means completely vertical at 90° or almost completely vertical. For example, within the range of an included angle of 80° to 100°, it is considered vertical. Similarly, "parallel" means completely parallel or almost completely parallel. For example, within the range of 10° of complete parallelism, it is considered parallel.

[0031] Carbon dioxide capture, utilization and storage technology is an important means to reduce carbon dioxide emissions, ensure energy security and achieve sustainable development. The main means at present is to inject liquid carbon dioxide into the ground through a carbon dioxide injection pump. Carbon dioxide can flow into the micropores of the formation and dissolve in crude oil, reducing the viscosity of crude oil and expanding its volume, thereby reducing the difficulty of crude oil extraction, increasing production, and achieving the purpose of increasing crude oil recovery. At the same time, during the carbon dioxide flooding process, a part of the carbon dioxide will be sealed in the formation, which will achieve carbon dioxide emission reduction while increasing the recovery rate. Liquid carbon dioxide injection pumps are all high-pressure and low-temperature working conditions. In addition, the characteristics of liquid carbon dioxide will rapidly expand and gasify when absorbing heat or reducing pressure, and produce very hard low-temperature carbon dioxide solid dry ice and ice cubes. In order to prevent carbon dioxide leakage, the compression force between the packing and the plunger will be very large. Due to friction, the liquid carbon dioxide will gasify on the working surface of the plunger and form solid dry ice. Such a complex and harsh working environment is more likely to wear the packing and plunger, which will cause a larger leakage, so that more solid dry ice will form on the surface of the plunger, and constantly cause a vicious cycle of working conditions. At present, the usual approach is to improve the plunger and filler materials, or reduce the friction coefficient between the plunger and the filler to increase the service life of the plunger, but the actual effect is not good.

[0032] In view of this, the present application provides a liquid carbon dioxide injection pump, including a boosting component, a plunger component, a first pipeline and a second pipeline, and the boosting component is used to boost the input liquid carbon dioxide. The plunger component includes a plunger body, a plunger shell, a first sealing filler and a second sealing filler, the plunger shell is enclosed to form a receiving chamber, the plunger body is located in the receiving chamber, the plunger body includes a first sub-plunger and a second sub-plunger connected to each other, the cross-sectional area of ​​the first sub-plunger is greater than the cross-sectional area of ​​the second sub-plunger, a flow channel is formed between the second sub-plunger and the plunger shell, the first sealing filler is sandwiched between the first sub-plunger and the plunger shell, and the second sealing filler is sandwiched between the second sub-plunger and the plunger shell; the first pipeline is used to input the pressurized liquid carbon dioxide into the flow channel. The second pipeline is connected to the plunger component, and the second pipeline is used to discharge the liquid carbon dioxide in the flow channel. By setting a second sub-plunger with a smaller cross-sectional area to form a flow channel with the plunger shell, the pressurized liquid carbon dioxide can take away part of the heat along the flow channel and flush out impurities or solid dry ice on the surface of the plunger body. In addition, the pressing force of the first sealing filler and the friction between the first sealing filler and the first sub-plunger can be reduced, thereby effectively extending the service life of the first sealing filler and the first sub-plunger.

[0033] The liquid carbon dioxide injection pump of the present application is described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the features of the following embodiments and implementations can be combined with each other.

[0034] Figure 1It is a schematic diagram of a liquid carbon dioxide injection pump according to an embodiment of the present application; Figure 2 It is a schematic structural diagram of a plunger body according to an embodiment of the present application; Figure 3 It is a sectional view of a liquid carbon dioxide injection pump according to an embodiment of the present application; Figure 4 It is Figure 3 An enlarged view of part A; Figure 5 It is Figure 3 An enlarged view of part B; Figure 6 It is a schematic structural diagram of a liquid carbon dioxide injection pump according to an embodiment of the present application.

[0035] Referring to Figures 1 to 6 , the present application provides a liquid carbon dioxide injection pump, including a boosting component 1, a plunger component 2, a first pipeline 3 and a second pipeline 4. The boosting component 1 is used to boost the input liquid carbon dioxide. The plunger component 2 includes a plunger body 20, a plunger housing 21, a first sealing packing 22 and a second sealing packing 23. The plunger housing 21 encloses a receiving cavity 24. The plunger body 20 is located in the receiving cavity 24. The plunger body 20 includes a connected first sub-plunger 200 and a second sub-plunger 201. The cross-sectional area of the first sub-plunger 200 is larger than that of the second sub-plunger 201. A flow channel 202 is formed between the second sub-plunger 201 and the plunger housing 21. The first sealing packing 22 is clamped between the first sub-plunger 200 and the plunger housing 21. The second sealing packing 23 is clamped between the second sub-plunger 201 and the plunger housing 21. The first pipeline 3 is used to input the boosted liquid carbon dioxide into the flow channel 202. The second pipeline 4 is communicated with the plunger component 2. The second pipeline 4 is used to discharge the liquid carbon dioxide in the flow channel 202. By providing the second sub-plunger 201 with a smaller cross-sectional area to form the flow channel 202 with the plunger housing 21, the boosted liquid carbon dioxide can take away part of the heat along the flow channel 202, effectively preventing the liquid carbon dioxide from vaporizing. The liquid carbon dioxide in the flow channel 202 can also wash away the impurities or solid dry ice on the surface of the plunger body 20, thereby effectively extending the service life of the plunger component 2. In addition, by reducing the pressure difference on both sides of the first sealing packing 22 during the boosting process, the pressing force of the first sealing packing 22 and the friction force between the first sealing packing 22 and the first sub-plunger 200 can be reduced, improving the working conditions between the plunger body 20, the first sealing packing 22 and the second sealing packing 23, thereby further extending the service life of the plunger component 2.

[0036] In Figure 3In the illustrated embodiment, the plunger housing 21 includes a first housing 210 and a second housing 211. The first housing 210 is connected to the first sub-plunger 200, and the second housing 211 is connected to the second sub-plunger 201. A flow channel 202 is formed between the second housing 211 and the second sub-plunger 201. At least a part of the first housing 210 overlaps the outer periphery of the second housing 211. The first housing 210 and the second housing 211 enclose a receiving cavity 24 to enable the plunger body 20 to move within the receiving cavity 24 and prevent leakage of liquid carbon dioxide and entry of external impurities into the receiving cavity 24. The flow channel 202 formed between the second housing 211 and the second sub-plunger 201 allows the pressurized liquid carbon dioxide to carry away part of the heat along the flow channel 202, effectively preventing the liquid carbon dioxide from vaporizing. The liquid carbon dioxide in the flow channel 202 can also wash away impurities or solid dry ice on the surface of the plunger body 20, thereby effectively extending the service life of the plunger assembly 2.

[0037] In Figure 3 In the illustrated embodiment, the first sealing packing 22 is clamped between the first sub-plunger 200 and the first housing 210, and the second sealing packing 23 is clamped between the second sub-plunger 201 and the second housing 211. The functions of the first sealing packing 22 and the second sealing packing 23 are to form a seal between the plunger body 20 and the plunger housing 21 to prevent leakage of liquid carbon dioxide. By filling the gap between the plunger housing 21 and the plunger body 20, the first sealing packing 22 and the second sealing packing 23 can reduce the direct contact between the first sub-plunger 200 and the plunger housing 21. When the plunger body 20 moves, the presence of the first sealing packing 22 and the second sealing packing 23 can reduce the frictional resistance of the plunger body 20 within the plunger housing 21 and reduce energy loss. In this application, by providing the second sub-plunger 201, the pressure difference on both sides of the first sealing packing 22 is reduced during the pressurization process, greatly reducing the pressing force of the first sealing packing 22, improving the working conditions of the friction working surfaces of the first sub-plunger 200 and the first sealing packing 22, greatly reducing the frictional force between the first sub-plunger 200 and the first sealing packing 22, and reducing the heat generated by friction. In addition, transferring the leakage between the first sub-plunger 200 and the first sealing packing 22 to the second sealing packing 23 can effectively extend the service lives of the plunger body 20, the first sealing packing 22, and the second sealing packing 23.

[0038] In Figure 3In the illustrated embodiment, the plunger housing 21 further includes a first adjusting member 212 and a second adjusting member 213. The first adjusting member 212 is disposed at the connection between the first housing 210 and the second housing 211 and is connected to the first housing 210 and the second housing 211 respectively. The first adjusting member 212 is disposed at the overlapping portion of the first housing 210 and the second housing 211. The pre-tightening force between the first sealing packing 22 and the first sub-plunger 200 can be adjusted through the first adjusting member 212 to ensure close contact between the first sealing packing 22 and the first sub-plunger 200, thereby preventing liquid carbon dioxide from leaking from the connection between the first housing 210 and the second housing 211 and improving the sealing performance of the plunger assembly 2. The second adjusting member 213 is disposed at one end of the second housing 211 away from the first housing 210 and is connected to the second sub-plunger 201 and the second housing 211 respectively. The pre-tightening force between the second sealing packing 23 and the second sub-plunger 201 can be adjusted through the second adjusting member 213 to ensure close contact between the second sealing packing 23 and the second sub-plunger 201, thereby preventing liquid carbon dioxide from leaking between the first housing 210 and the second sub-plunger 201 and improving the sealing performance of the plunger assembly 2.

[0039] In Figure 4 In the illustrated embodiment, the plunger assembly 2 includes a first seal 25, and the first seal 25 is clamped between the first housing 210 and the second housing 211. Disposing the first seal 25 at the overlapping portion of the first housing 210 and the second housing 211 can further improve the sealing performance of the plunger assembly 2 and prevent liquid carbon dioxide from leaking from the overlapping portion of the first housing 210 and the second housing 211.

[0040] In some embodiments, the pressurizing assembly 1 has a first inlet 10 and a first outlet 11, the plunger housing 21 has a second inlet 214 and a second outlet 215, the second inlet 214 and the second outlet 215 are respectively communicated with the flow channel 202, the first pipeline 3 communicates the first outlet 11 and the second inlet 214, and the second pipeline 4 communicates the first inlet 10 and the second outlet 215. In some embodiments, the pressurizing assembly 1 further includes a pressurizing flow channel 12 and a plurality of one-way valves 13 arranged on the pressurizing flow channel 12, and the pressurizing flow channel 12 is communicated with the accommodating cavity 24. The plunger body 20 reciprocates in the accommodating cavity 24 and at least part of the pressurizing flow channel 12 under the drive of the driving member 5. The liquid carbon dioxide enters the pressurizing assembly 1 through the first inlet 10. The plunger body 20 moves in the accommodating cavity 24 and at least part of the pressurizing flow channel 12 to generate negative pressure. The liquid carbon dioxide forms high-pressure and low-temperature liquid carbon dioxide under the action of pressure. The high-pressure and low-temperature liquid carbon dioxide is discharged from the pressurizing assembly 1 through the plurality of one-way valves 13 and the first outlet 11 and enters the accommodating cavity 24 through the first pipeline 3 and the second inlet 214 on the plunger housing 21. The high-pressure and low-temperature liquid carbon dioxide flows in the flow channel 202, which can take away the heat generated by the friction between the plunger body 20, the first sealing packing 22 and the second sealing packing 23, and can also wash away the impurities or solid dry ice on the surface of the plunger body 20. The liquid carbon dioxide in the flow channel 202 is discharged from the plunger assembly 2 through the second outlet 215 on the plunger housing 21 and flows to the first inlet 10 of the pressurizing assembly 1 through the second pipeline 4. With such a setting, the service lives of the plunger body 20, the first sealing packing 22 and the second sealing packing 23 can be effectively prolonged.

[0041] In Figure 3 and Figure 5 In the embodiment shown, the one-way valve 13 includes a first valve seat 130, a second valve seat 131 and a ball valve 132. The first valve seat 130 has a guiding hole 1300, the second valve seat 131 has a liquid discharge hole 1310. The first valve seat 130 and the second valve seat 131 enclose an accommodating space 133. The ball valve 132 is located in the accommodating space 133 and is movably arranged in the guiding hole 1300. The ball valve 132 is installed in the accommodating space formed by the enclosure of the first valve seat 130 and the second valve seat 131. The lower end of the ball valve 132 contacts the guiding hole 1300 of the first valve seat 130 to play a sealing role. The ball valve 132 can move up and down in the accommodating space 133. When moving upward, it opens and the liquid carbon dioxide can flow through; when moving downward, it closes and the liquid carbon dioxide cannot flow through. As Figure 2As shown, when the plunger body 20 moves away from the supercharging assembly 1, a negative pressure is generated in the accommodation cavity 24 and at least part of the supercharging flow channel 12. Under the action of the pressure, the check valve 13 below the supercharging assembly 1 opens, and the check valve 13 above closes. The liquid carbon dioxide is sucked into the accommodation cavity 24. When the plunger moves towards the side close to the supercharging assembly 1, a positive pressure is generated in the accommodation cavity 24 and at least part of the supercharging flow channel 12. The pressure closes the check valve 13 below the supercharging assembly 1 and opens the check valve 13 above, and the high-pressure liquid carbon dioxide is discharged from the accommodation cavity 24.

[0042] In Figure 3 and Figure 5 In the embodiment shown, the check valve 13 includes a second seal 134, and the second seal 134 is clamped between the first valve seat 130 and the second valve seat 131. Arranging the second seal 134 between the first valve seat 130 and the second valve seat 131 can effectively improve the sealing performance of the supercharging assembly 1 and prevent the leakage of liquid carbon dioxide.

[0043] In Figure 1 and Figure 6 In the embodiment shown, the number of the plunger assemblies 2 is multiple, and each plunger assembly 2 is correspondingly provided with a first pipeline 3 and a second pipeline 4. The multiple plunger assemblies 2 are connected in parallel to the supercharging assembly 1. Increasing the plunger assemblies 2 can increase the flow rate and pressure of the liquid carbon dioxide injection pump and improve the stability of the system.

[0044] In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0045] The above has introduced in detail a liquid carbon dioxide injection pump provided by the embodiments of the present application, and specific examples are used to elaborate the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of the present application; those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A liquid carbon dioxide injection pump, characterized in that: include: A pressurizing component (1), the pressurizing component (1) being used to pressurize input liquid carbon dioxide; A plunger assembly (2), comprising a plunger body (20), a plunger shell (21), a first sealing filler (22) and a second sealing filler (23), wherein the plunger shell (21) encloses a receiving cavity (24), the plunger body (20) is located in the receiving cavity (24), the plunger body (20) comprises a first sub-plunger (200) and a second sub-plunger (201) connected to each other, the cross-sectional area of ​​the first sub-plunger (200) is greater than the cross-sectional area of ​​the second sub-plunger (201), a flow channel (202) is formed between the second sub-plunger (201) and the plunger shell (21), the first sealing filler (22) is sandwiched between the first sub-plunger (200) and the plunger shell (21), and the second sealing filler (23) is sandwiched between the second sub-plunger (201) and the plunger shell (21); a first pipeline (3) connected to the pressurizing assembly (1) and the plunger assembly (2), the first pipeline (3) being used to input the pressurized liquid carbon dioxide into the flow channel (202); A second pipeline (4) is connected to the plunger assembly (2), and the second pipeline (4) is used to discharge the liquid carbon dioxide in the flow channel (202).

2. The liquid carbon dioxide injection pump according to claim 1, characterized in that: The plunger housing (21) comprises a first housing (210) and a second housing (211); the first housing (210) is connected to the first sub-plunger (200); the second housing (211) is connected to the second sub-plunger (201); the flow channel (202) is formed between the second housing (211) and the second sub-plunger (201); and at least a portion of the first housing (210) overlaps the outer periphery of the second housing (211).

3. The liquid carbon dioxide injection pump according to claim 2, characterized in that: The first sealing filler (22) is sandwiched between the first sub-plunger (200) and the first housing (210); the second sealing filler (23) is sandwiched between the second sub-plunger (201) and the second housing (211).

4. The liquid carbon dioxide injection pump according to claim 3, characterized in that: The plunger housing (21) further comprises: a first adjusting member (212), the first adjusting member (212) being arranged at a connection between the first shell (210) and the second shell (211), and being connected to the first shell (210) and the second shell (211) respectively; A second adjusting member (213), wherein the second adjusting member (213) is disposed at one end of the second housing (211) away from the first housing (210), and is respectively connected to the second sub-plunger (201) and the second housing (211).

5. The liquid carbon dioxide injection pump according to claim 2, characterized in that: The plunger assembly (2) comprises a first sealing member (25), wherein the first sealing member (25) is sandwiched between the first housing (210) and the second housing (211).

6. The liquid carbon dioxide injection pump according to claim 1, characterized in that: The booster assembly (1) has a first inlet (10) and a first outlet (11), the plunger housing (21) has a second inlet (214) and a second outlet (215), the second inlet (214) and the second outlet (215) are respectively connected to the flow channel (202), the first pipeline (3) is connected to the first outlet (11) and the second inlet (214), and the second pipeline (4) is connected to the first inlet (10) and the second outlet (215).

7. The liquid carbon dioxide injection pump according to claim 1, characterized in that: The boosting assembly (1) further comprises a boosting flow channel (12) and a plurality of one-way valves (13) arranged on the boosting flow channel (12); the boosting flow channel (12) is in communication with the accommodating chamber (24).

8. The liquid carbon dioxide injection pump according to claim 7, characterized in that: The one-way valve (13) includes a first valve seat (130), a second valve seat (131) and a ball valve (132); the first valve seat (130) has a guide hole (1300), the second valve seat (131) has a drainage hole (1310), the first valve seat (130) and the second valve seat (131) enclose a receiving space (133); the ball valve (132) is located in the receiving space (133) and can be movably arranged in the guide hole (1300).

9. The liquid carbon dioxide injection pump according to claim 8, characterized in that: The one-way valve (13) comprises a second sealing member (134), wherein the second sealing member (134) is sandwiched between the first valve seat (130) and the second valve seat (131).

10. The liquid carbon dioxide injection pump according to claim 1, characterized in that: There are a plurality of plunger assemblies (2), each of which is provided with a corresponding first pipeline (3) and a corresponding second pipeline (4), and a plurality of plunger assemblies (2) are connected in parallel to the boosting assembly (1).

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