Cylinder seal low-resistance dense-phase carbon dioxide booster pump

Abstract

This invention discloses a cylinder-driven, sealed, low-resistance, dense-phase carbon dioxide booster pump, belonging to the field of plunger pump technology. It includes: a housing with an inlet chamber and an outlet chamber, the inlet chamber being connected to an inlet port on the housing; a movable cylinder housed within the housing; when the movable cylinder moves to one end, a negative pressure is created at the inlet port, allowing liquid carbon dioxide from the inlet chamber to enter the outlet chamber; when the movable cylinder reaches the other end, the outlet chamber is sealed; a plunger extends into the movable cylinder; when the plunger moves within the housing, a volume change is created, thereby drawing in and compressing liquid carbon dioxide; a spring is sleeved around the plunger and located between the movable cylinder and the housing, applying resistance or thrust to the movable cylinder. This invention has a wide range of applications, particularly suitable for the operating conditions of carbon dioxide flooding in oil fields, effectively reducing kinetic energy loss by more than 5%. It adopts a reciprocating working principle, possessing good controllability and low investment cost, thus ensuring the stability of the carbon dioxide flooding injection process.

Description

Technical Field

[0001] This invention relates to the field of plunger pump technology, specifically to a cylinder-driven, low-resistance, dense-phase carbon dioxide booster pump. Background Technology

[0002] With the goals of carbon peaking and carbon neutrality being set, China's carbon dioxide storage technology has entered a new stage of rapid development, with major oilfields exploring and developing carbon dioxide enhanced oil recovery (EOR) technologies. Currently, carbon dioxide injection methods mainly focus on liquid-phase and supercritical injection.

[0003] Existing domestic dense-phase pumps employ a negative pressure suction method during carbon dioxide injection. This method reduces the pump's volumetric efficiency, leading to low overall equipment operating efficiency. This inefficiency results in increased energy consumption during operation, raising operating costs and hindering energy conservation and emission reduction. More importantly, this negative pressure suction method is unsuitable for large-scale carbon dioxide flooding processes in oilfields, as it cannot meet the demands of large-scale, high-efficiency carbon dioxide injection, as illustrated in Chinese patent application CN116538428A.

[0004] In contrast, while there are relatively mature injection equipment abroad, their prices are exorbitant, often several times or even ten times higher than liquefied carbon dioxide injection pumps, and their operating efficiency is not high. Therefore, the demand for affordable and efficient carbon dioxide injection equipment is becoming increasingly urgent in China. Summary of the Invention

[0005] The purpose of this invention is to provide a cylinder-driven, low-resistance, dense-phase carbon dioxide booster pump that can effectively utilize kinetic energy, reduce the loss of ineffective kinetic energy, is suitable for carbon dioxide flooding operation in oil fields, has a wide range of applicable parameters, and is highly safe.

[0006] To achieve the above objectives, the technical solution of this application is: a cylinder-driven, sealed, low-resistance dense-phase carbon dioxide booster pump, comprising:

[0007] The housing has a liquid inlet chamber and a liquid outlet chamber, wherein the liquid inlet chamber is connected to the liquid inlet on the housing.

[0008] A movable cylinder is installed inside the housing; when the movable cylinder moves to one end, a negative pressure is formed at the inlet, and the liquid phase carbon dioxide in the inlet chamber enters the outlet chamber; when the movable cylinder reaches the other end, the outlet chamber is sealed.

[0009] A plunger extends into a movable cylinder; as the plunger moves within the housing, it creates a volume change, thereby drawing in and compressing liquid carbon dioxide.

[0010] A spring, fitted around the outer circumference of the plunger and located between the movable cylinder and the housing, applies resistance or thrust to the movable cylinder.

[0011] In one embodiment, one end of the plunger extends out of the housing and is connected to the electric motor via a crank connecting rod.

[0012] In one embodiment, the outer peripheral surface of the plunger and / or the inner wall surface of the movable cylinder are coated with a damping lubricating material.

[0013] In one embodiment, a damping lubrication block is provided between the outer wall of the movable cylinder and the inner wall of the housing.

[0014] In one embodiment, during movement, the displacement length of the movable cylinder is always less than the displacement length of the plunger.

[0015] In one embodiment, a cylinder cover is connected to one side of the housing, and a liquid outlet is provided on the cylinder cover, which is connected to the liquid outlet chamber.

[0016] In one embodiment, a one-way valve is provided at the inlet. When the movable cylinder moves away from the outlet, a negative pressure is formed at the inlet. At this time, the one-way valve opens, and the liquid carbon dioxide in the inlet chamber enters the outlet chamber. When the plunger compresses the liquid carbon dioxide to form a positive pressure, the one-way valve closes.

[0017] In one embodiment, the liquid outlet is equipped with a liquid outlet check valve. When the movable cylinder moves toward the liquid outlet and reaches the cylinder head, the liquid outlet chamber is sealed. The plunger continues to move toward the liquid outlet to compress the liquid phase carbon dioxide. When the required pressure of the liquid outlet chamber is reached, the liquid outlet check valve opens to complete the liquid outlet operation. As the plunger moves away from the liquid outlet, when the pressure of the liquid outlet chamber is less than the required pressure, the liquid outlet check valve closes.

[0018] In one embodiment, when the movable cylinder moves to its limit away from the outlet, it moves towards the outlet under the damping action of the plunger and the thrust of the spring.

[0019] In one embodiment, the liquid outlet check valve is positioned opposite to the movable cylinder.

[0020] This invention, by employing the above technical solutions, achieves the following technical effects: The cylinder-driven, sealed, low-resistance dense-phase carbon dioxide booster pump of this invention has a wide range of applications, particularly suitable for the operating conditions of carbon dioxide flooding in oil fields, effectively reducing kinetic energy loss by more than 5%. It adopts a reciprocating working principle, possessing good controllability, low investment cost, and ease of maintenance, thus ensuring the stability of the carbon dioxide flooding injection process. Furthermore, the pump body structure is equipped with complete safety facilities, enabling unattended operation or remote control management. This innovation not only stabilizes my country's energy supply but also effectively promotes the smooth achievement of the "dual carbon" target. Attached Figure Description

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

[0022] Figure 1 A schematic diagram of a low-resistance dense-phase carbon dioxide booster pump with a cylinder-driven seal during liquid inlet.

[0023] Figure 2 This is a schematic diagram of a cylinder-driven, low-resistance, dense-phase carbon dioxide booster pump with a sealed cylinder during liquid discharge.

[0024] The numbers in the diagram are explained as follows: 1. Housing; 2. Movable cylinder; 3. Plunger; 4. Inlet check valve; 5. Spring; 6. Outlet check valve; 7. Cylinder head; 8. Inlet chamber; 9. Outlet chamber. Detailed Implementation

[0025] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0026] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0027] In the description of this application, it should be understood that the terms "center", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not 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 application.

[0028] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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 application according to the specific circumstances.

[0029] This embodiment provides a cylinder-driven, sealed, low-resistance, dense-phase carbon dioxide booster pump, including an electric motor, a crank-connecting rod driven by the electric motor, a piston driven by the crank-connecting rod to reciprocate, a movable cylinder body that cooperates with the piston to form a booster chamber, a cylinder head provided at the end of the cylinder body, an outlet check valve located at the outlet of the cylinder head, and an inlet check valve located at the inlet of the housing. There is at least one inlet check valve and one outlet check valve.

[0030] A layer of damping lubricating material is coated between the plunger and the movable cylinder in the pressurization chamber. One end of the spring is connected to a spring seat on one side of the housing, and the other end is connected to the movable cylinder. The outer wall of the movable cylinder is connected to the inner wall of the housing, and a damping lubricating block is provided in the middle.

[0031] The aforementioned movable cylinder can move along with the plunger. When the crank connecting rod moves forward, the movable cylinder moves forward with the plunger until it reaches its limit position. The plunger continues to move forward to compress the liquid carbon dioxide. When the plunger moves backward, the movable cylinder moves backward with the plunger until it reaches the maximum value of the spring force and stops moving. At this point, it reaches the cylinder head position and the plunger continues to move. During the movement, the displacement length of the movable cylinder is always less than the displacement length of the plunger.

[0032] This invention improves the cavity by enlarging the inlet flow channel to more closely match the cylinder diameter, thereby reducing inlet resistance and ensuring inlet efficiency. Simultaneously, the outlet check valve faces directly onto the cylinder front, reducing cylinder clearance and increasing the pump's volumetric efficiency from the currently tested 80% to 93%, further enhancing pump efficiency. The packing pressure differential is dispersed, thus reducing the pressure difference between the cylinder interior and exterior, increasing the durability of the sealing packing, and extending its service life.

[0033] This invention utilizes the reciprocating principle, enabling a movable cylinder and a plunger to reciprocate in close cooperation, compressing a dense-phase carbon dioxide medium to achieve pressurization. Specifically, it includes...

[0034] Shell 1: Protects internal components and has a liquid inlet chamber and a liquid outlet chamber, wherein the liquid inlet chamber is connected to the liquid inlet on the shell;

[0035] Movable cylinder 2: The key feature of this invention is that the cylinder is different from the previous plunger pump. The hydraulic end is designed as a movable cylinder, which is closely matched with the plunger 3. With the damping effect between the cylinder and the plunger 3 and the resistance effect of the spring 5, it moves away from the liquid outlet. At this time, the liquid inlet forms a negative pressure, the liquid inlet check valve 4 opens, and the liquid in the liquid inlet chamber 8 enters the liquid outlet chamber 9. When the movable cylinder 2 moves to the limit, it moves towards the liquid outlet under the damping effect of the plunger 3 and the thrust effect of the spring 5, and reaches the vicinity of the liquid outlet before the plunger 3. The plunger 3 continues to move to compress the liquid inlet to achieve the purpose of pressurization.

[0036] Piston 3: It is closely fitted with movable cylinder 2. Under the action of crank connecting rod, it moves to form a volume change, thereby drawing in and compressing liquid carbon dioxide.

[0037] Inlet check valve 4: When a negative pressure is formed in the inlet chamber, the inlet check valve opens; when a positive pressure is formed by the plunger compressing the inlet liquid, the inlet check valve closes.

[0038] Spring 5: It is sleeved on the outer periphery of the plunger 3. As the plunger 3 moves with the movable cylinder 2, it applies resistance or thrust to the movable cylinder.

[0039] Discharge check valve 6: When the discharge chamber reaches the required pressure, the discharge check valve opens; when the pressure in the discharge chamber is less than the required pressure as the plunger moves away from the discharge port, the discharge check valve closes.

[0040] Cylinder head 7: Protects internal components and has a liquid outlet on it;

[0041] Inlet chamber 8: When a negative pressure is formed in the inlet chamber 8, the inlet check valve 4 opens, and liquid enters the inlet chamber 8;

[0042] Discharge chamber 9: When the liquid in the discharge chamber 9 is compressed to the required pressure, the discharge check valve 6 opens;

[0043] It should be noted that the principle of the cylinder-driven, low-resistance dense-phase carbon dioxide booster pump is the same as that of a plunger pump. It relies on a plunger driving a movable cylinder to reciprocate, causing a change in the volume of the sealed working cavity to pressurize the dense-phase carbon dioxide. Specifically, this includes...

[0044] ① During the liquid inlet operation, the plunger moves away from the liquid outlet under the drive of the crank connecting rod. Due to the friction between the movable cylinder and the plunger, the movable cylinder also moves away from the liquid outlet along with the plunger under the action of friction. The liquid inlet chamber generates negative pressure, and the liquid inlet check valve opens. Under the action of the spring, the opening range of the chamber is limited, and the plunger continues to move to the limit with the crank connecting rod. At this time, the liquid inlet is completed.

[0045] ② During the liquid discharge operation, the plunger moves towards the liquid outlet under the drive of the crank connecting rod. The movable cylinder also moves towards the liquid outlet under the combined action of friction between the plunger and the spring. When it reaches the cylinder head, it seals the liquid outlet chamber. At this time, the plunger continues to move towards the liquid outlet to compress the liquid phase carbon dioxide. When the required pressure of the liquid outlet chamber is reached, the liquid outlet check valve opens, completing the liquid discharge operation.

[0046] Based on the later-stage carbon dioxide injection plan of a certain oilfield, the outlet pressure is set at 25 MPa, and the flow rate is 15 cubic meters per hour. According to the actual usage conditions at the oilfield, the stable state is as follows: motor frequency 37 Hz, inlet pressure stable at 7.6 MPa, outlet pressure 18.8 MPa, flow rate approximately 10 cubic meters per hour, and pump outlet temperature below 60℃. Compared with existing plunger pumps, this pump operates stably. By reducing volumetric losses, kinetic energy loss is reduced by more than 5%. Preliminary calculations show a pump efficiency >76.6% (mechanical efficiency, excluding thermal efficiency), with a unit power consumption of 7.7-9.1 kW·h / m³. 3 It improves production efficiency while reducing energy consumption, and is very suitable for pressurized injection of easily compressible gases such as carbon dioxide.

[0047] This invention, targeting the actual operating conditions of carbon dioxide flooding in oilfields, further explores and develops a cylinder-driven, sealed, low-resistance dense-phase carbon dioxide booster pump based on the plunger pump. This equipment effectively utilizes kinetic energy, reduces the loss of ineffective kinetic energy, and increases efficiency by 5%. With an inlet operating pressure of 10–25 MPa and a temperature of -40–60℃, it is suitable for the operating conditions of carbon dioxide flooding in oilfields. It offers good controllability, low investment, easy maintenance, and ensures the stability of carbon dioxide injection. Its parameters have a wide range of applications and high safety, enabling low-cost operation of carbon dioxide flooding in oilfields.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended 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 of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A cylinder-driven, low-resistance, dense-phase carbon dioxide booster pump, characterized in that, include: The housing has a liquid inlet chamber and a liquid outlet chamber, wherein the liquid inlet chamber is connected to the liquid inlet on the housing. The movable cylinder is housed within the casing; When the movable cylinder moves to one end, a negative pressure is formed at the inlet, and the liquid phase carbon dioxide in the inlet chamber enters the outlet chamber. When the movable cylinder reaches the other end, the liquid outlet chamber is sealed. The plunger extends into the movable cylinder body; As the plunger moves within the housing, it creates a volume change, thereby drawing in and compressing liquid carbon dioxide. A spring, fitted around the outer circumference of the plunger and located between the movable cylinder and the housing, applies resistance or thrust to the movable cylinder.

2. The cylinder-driven, low-resistance, dense-phase carbon dioxide booster pump according to claim 1, characterized in that, One end of the plunger extends out of the housing and is connected to the electric motor via a crank connecting rod.

3. The cylinder-driven, low-resistance, dense-phase carbon dioxide booster pump according to claim 1, characterized in that, The outer peripheral surface of the plunger and / or the inner wall surface of the movable cylinder are coated with a layer of damping lubricating material.

4. The cylinder-driven, low-resistance, dense-phase carbon dioxide booster pump according to claim 1, characterized in that, A damping lubrication block is provided between the outer wall of the movable cylinder and the inner wall of the housing.

5. The cylinder-driven, low-resistance, dense-phase carbon dioxide booster pump according to claim 1, characterized in that, During movement, the displacement length of the movable cylinder is always less than the displacement length of the plunger.

6. The cylinder-driven, low-resistance, dense-phase carbon dioxide booster pump according to claim 1, characterized in that, A cylinder cover is connected to one side of the housing, and a liquid outlet is provided on the cylinder cover, which is connected to the liquid outlet chamber.

7. The cylinder-driven, low-resistance, dense-phase carbon dioxide booster pump according to claim 6, characterized in that, The inlet is equipped with a one-way valve. When the movable cylinder moves away from the outlet, a negative pressure is formed at the inlet. At this time, the one-way valve opens, and the liquid carbon dioxide in the inlet chamber enters the outlet chamber. As the plunger compresses the liquid carbon dioxide to form a positive pressure, the one-way valve closes.

8. The cylinder-driven, low-resistance, dense-phase carbon dioxide booster pump according to claim 6, characterized in that, The outlet is equipped with a one-way valve. When the movable cylinder moves toward the outlet and reaches the cylinder head, the outlet chamber is sealed. The plunger continues to move toward the outlet to compress the liquid carbon dioxide. When the required pressure in the outlet chamber is reached, the one-way valve opens to complete the outlet operation. As the plunger moves away from the outlet, when the pressure in the outlet chamber is less than the required pressure, the one-way valve closes.

9. The cylinder-driven, low-resistance, dense-phase carbon dioxide booster pump according to claim 6, characterized in that, When the movable cylinder moves to its limit away from the outlet, it moves towards the outlet under the damping action of the plunger and the thrust of the spring.

10. The cylinder-driven, low-resistance, dense-phase carbon dioxide booster pump according to claim 8, characterized in that, The liquid outlet check valve is positioned opposite to the movable cylinder.

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