Carbon dioxide high pressure centrifugal pump with sealed buffer chamber
By setting up a buffer chamber between the pump chamber and the mechanical seal mechanism and controlling the medium inside to be in a gaseous state, the problem of medium contamination by the isolation liquid in high-pressure carbon dioxide transfer pumps is solved, achieving stable and efficient liquid carbon dioxide transfer and reducing costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- EBARA GREAT PUMPS
- Filing Date
- 2025-07-24
- Publication Date
- 2026-06-16
Smart Images
Figure CN120667410B_ABST
Abstract
Description
Technical Field
[0001] This specification relates to the field of high-pressure pump technology, and in particular to a carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber. Background Technology
[0002] Carbon capture, utilization, and storage (CCUS) technology can effectively reduce carbon emissions from fossil fuel combustion and industrial processes. With the increasing prevalence of CCUS-related devices, the demand for high-pressure carbon dioxide centrifugal pumps, as key pumps in CCUS-related systems, is gradually increasing.
[0003] However, due to the extremely poor lubricity of carbon dioxide, users and pump manufacturers have been troubled when selecting a mechanical seal flushing solution for a high-pressure carbon dioxide centrifugal pump, especially in operating conditions where the medium cannot be contaminated, because the high-pressure isolation fluid inside the mechanical seal inevitably risks entering the pump chamber and contaminating the medium during operation. Summary of the Invention
[0004] In view of the shortcomings of the prior art, one object of this specification is to provide a high-pressure centrifugal pump for carbon dioxide with a sealed buffer chamber, which can efficiently transport liquid carbon dioxide and effectively prevent the high-pressure isolation liquid in the mechanical seal from entering the pump chamber.
[0005] To achieve the above objectives, this specification provides an embodiment of a high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber, comprising:
[0006] The outer casing has an internal pump chamber;
[0007] An inlet provided on the outer casing is used for introducing a medium;
[0008] An outlet provided on the outer casing is used to output the medium;
[0009] A rotating shaft rotatably passes through the pump chamber; support assemblies supporting the rotating shaft are respectively provided at both ends of the outer casing; a multi-stage impeller is fixedly connected to the rotating shaft, and the multi-stage impeller is located inside the pump chamber for pumping the medium from the inlet to the outlet;
[0010] A mechanical seal mechanism is disposed between the support assembly and the pump chamber. A buffer chamber is provided between the mechanical seal mechanism and the pump chamber. The buffer chamber is connected to the pump chamber and the mechanical seal mechanism respectively, and is used to collect the medium leaked in the pump chamber and the isolation liquid leaked in the mechanical seal mechanism.
[0011] An exhaust pipe connected to the buffer chamber is provided with an exhaust valve; the exhaust valve controls the medium in the buffer chamber to be in a gaseous state.
[0012] In a preferred embodiment, the support assembly includes a drive-side bearing assembly and a non-drive-side bearing assembly, with one end of the rotating shaft passing through the drive-side bearing assembly and connected to the motor; the mechanical seal mechanism is of two types, one located between the drive-side bearing assembly and the pump chamber, and the other located between the non-drive-side bearing assembly and the pump chamber; the buffer chamber is of two types.
[0013] In a preferred embodiment, the bottom of the buffer chamber is connected to a drain pipe for draining the isolation liquid in the buffer chamber; the drain pipe is equipped with a drain valve.
[0014] In a preferred embodiment, the exhaust pipe is connected to the top of the buffer chamber.
[0015] In a preferred embodiment, the buffer cavity is provided with an isolation bushing, one end of which is fixedly sleeved on the rotating shaft, and the other end has a first blocking portion extending toward the pump cavity.
[0016] In a preferred embodiment, the buffer cavity is further provided with an isolation ring, which is located between the isolation bushing and the pump cavity; a gap is provided between the first blocking part and the isolation ring.
[0017] In a preferred embodiment, the end of the isolation ring away from the isolation bushing is fixedly connected to the inner wall of the buffer cavity.
[0018] In a preferred embodiment, the isolation ring has a second blocking portion extending toward the mechanical sealing mechanism at one end near the isolation bushing. The second blocking portion is located inside the first blocking portion and has a gap between them.
[0019] In a preferred embodiment, the outer diameter of the first blocking part is smaller than the outer diameter of the buffer cavity, and the inner diameter of the second blocking part is larger than the inner diameter of the buffer cavity; both the first blocking part and the second blocking part extend axially.
[0020] In a preferred embodiment, a volute is provided inside the pump chamber and sleeved outside the impeller; an inner shell is fixed to the inner wall of the outer shell, and the volute is fixedly connected to the inner shell; the volute, the inner wall of the inner shell, and the rotating shaft form a flow channel for the medium. Beneficial effects
[0021] The high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber provided in this embodiment collects leaked media from the pump chamber and leaked isolation fluid from the mechanical seal by setting a buffer chamber between the pump chamber and the mechanical seal mechanism. An exhaust pipe is connected to the buffer chamber, and an exhaust valve on the exhaust pipe controls the pressure inside the buffer chamber, causing the medium entering the buffer chamber to change from a liquid to a gaseous state. Since the buffer chamber contains a gaseous medium rather than a liquid, even if the isolation fluid from the mechanical seal mechanism leaks, it will not enter the pump body (i.e., the pump chamber). The leaked isolation fluid accumulates at the bottom of the buffer chamber. When the mechanical seal mechanism's replenishment cycle expires, the buffer chamber can be drained while replenishing the mechanical seal mechanism, thus ensuring the normal and stable operation of the pump. Therefore, the high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber provided in this application can efficiently transport liquid carbon dioxide and effectively prevent the high-pressure isolation fluid from the mechanical seal from entering the pump chamber.
[0022] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the invention can be employed. It should be understood that the embodiments of the present invention are not limited in scope as a result.
[0023] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.
[0024] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of the present 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 This is a cross-sectional structural diagram of a high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber provided in this embodiment.
[0027] Figure 2 for Figure 1 Enlarged structural diagram at point A;
[0028] Figure 3 for Figure 2 A schematic diagram of the structure of the middle isolation bushing and isolation ring on one side.
[0029] Explanation of reference numerals in the attached figures:
[0030] 1. Outer shell; 2. Pump chamber; 3. Inlet; 4. Outlet; 5. Rotating shaft; 6. Drive-side bearing assembly; 7. Non-drive-side bearing assembly; 8. Impeller; 9. Mechanical seal mechanism; 10. Volute; 11. Inner shell; 12. Buffer chamber; 13. Exhaust pipe; 14. Exhaust valve; 15. Drain pipe; 16. Drain valve; 17. Isolation bushing; 171. First blocking part; 18. Isolation ring; 181. Second blocking part; 19. Clearance; X, Axial direction. Detailed Implementation
[0031] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.
[0032] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or may be interposed with another element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.
[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0034] Please see Figures 1 to 3 This application provides a high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber 12, comprising: an outer casing 1, an inlet 3, an outlet 4, a rotating shaft 5, a mechanical seal mechanism 9, and an exhaust pipe 13.
[0035] The outer casing 1 contains a pump chamber 2. An inlet 3 is located on the outer casing 1 for introducing the medium. An outlet 4 is located on the outer casing 1 for discharging the medium. A rotating shaft 5 rotatably passes through the pump chamber 2. Support assemblies supporting the rotating shaft 5 are located at both ends of the outer casing 1. A multi-stage impeller 8 is fixedly connected to the rotating shaft 5, located within the pump chamber 2, for pumping the medium from the inlet 3 to the outlet 4. A mechanical seal mechanism 9 is located between the support assemblies and the pump chamber 2. A buffer chamber 12 is located between the mechanical seal mechanism 9 and the pump chamber 2, communicating with both the pump chamber 2 and the mechanical seal mechanism 9, for collecting leaked medium from the pump chamber 2 and leaked isolation fluid from the mechanical seal mechanism 9. An exhaust pipe 13 is connected to the buffer chamber 12. An exhaust valve 14 is located on the exhaust pipe 13. The exhaust valve 14 controls the medium in the buffer chamber 12 to be in a gaseous state.
[0036] It should be noted that the high-pressure carbon dioxide centrifugal pump with sealed buffer chamber 12 is mainly used to transport liquid CO2, i.e., the aforementioned medium is liquid CO2. Of course, this high-pressure carbon dioxide centrifugal pump can also be used to transport other easily vaporized light hydrocarbon media to improve efficiency. The embodiments of this application do not limit the number of impellers 8.
[0037] Due to the extremely poor lubricity of carbon dioxide, only Plan 53B, where the dynamic and static rings rely on a separator fluid for lubrication, can be selected when choosing a mechanical seal flushing solution. However, because the high-pressure separator fluid in Plan 53B inevitably enters the pump chamber 2 and contaminates the medium during operation, this solution is not suitable for pumping carbon dioxide where contamination is unacceptable.
[0038] Therefore, the carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber 12 provided in this embodiment separates the easily vaporizable pumping medium from the isolation liquid of the mechanical seal 9 by setting the buffer chamber 12 between the pump chamber 2 and the mechanical seal mechanism 9, ensuring that the pumping medium is not contaminated. It can also collect the medium leaking from the pump chamber 2 and the isolation liquid leaking from the mechanical seal mechanism 9. Furthermore, an exhaust pipe 13 is connected to the buffer chamber 12, and the pressure inside the buffer chamber 12 is controlled by an exhaust valve 14 on the exhaust pipe 13, causing the medium entering the buffer chamber 12 to change from a liquid state to a gaseous state. Since the buffer chamber 12 contains a gaseous medium rather than a liquid medium, even if the isolation liquid of the mechanical seal mechanism 9 leaks, it will not enter the pump body (i.e., the pump chamber 2). The leaked isolation liquid will accumulate at the bottom of the buffer chamber 12. When the replenishment cycle of the mechanical seal mechanism 9 expires, the buffer chamber 12 can be drained while replenishing the mechanical seal mechanism 9, thus ensuring the normal and stable operation of the pump.
[0039] Therefore, the high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber 12 provided in this application can efficiently transport liquid carbon dioxide and effectively prevent the high-pressure isolation fluid in the mechanical seal from entering the pump chamber 2. Furthermore, the mechanical seal mechanism 9 required by this invention does not require a special design like the mechanical seals used in general centrifugal pumps for transporting carbon dioxide; its structure can be a common mechanical seal, and the applicable isolation fluid can be a general-purpose commercial isolation fluid, thereby greatly reducing design and operating costs.
[0040] In this embodiment, the support assembly includes a drive-side bearing assembly 6 and a non-drive-side bearing assembly 7. One end of the rotating shaft 5 passes through the drive-side bearing assembly 6 and is connected to the motor. There are two mechanical seal mechanisms 9, one located between the drive-side bearing assembly 6 and the pump chamber 2, and the other located between the non-drive-side bearing assembly 7 and the pump chamber 2. Correspondingly, there are two buffer chambers 12. The buffer chambers 12 are approximately annular in shape.
[0041] like Figure 1 As shown, a drain pipe 15 is connected to the bottom of the buffer chamber 12 for draining the isolation fluid inside the buffer chamber 12. A drain valve 16 is installed on the drain pipe 15; when the isolation fluid collected in the buffer chamber 12 needs to be drained, the drain valve 16 is opened. The isolation fluid entering the buffer chamber 12 can be recycled after discharge, reducing the consumption of the isolation fluid.
[0042] Specifically, the exhaust pipe 13 is connected to the top of the buffer chamber 12 to prevent the isolation fluid in the buffer chamber 12 from entering the exhaust pipe 13.
[0043] like Figure 1 and Figure 2 As shown, an isolation bushing 17 is provided inside the buffer chamber 12. One end of the isolation bushing 17 is fixedly sleeved on the rotating shaft 5, and the other end has a first blocking part 171 extending toward the pump chamber 2. The extending direction of the first blocking part 171 is consistent with the flow direction of the isolation fluid leaking from the mechanical seal mechanism 9. When the mechanical seal mechanism 9 leaks over a large area, the sprayed isolation fluid can be blocked by the first blocking part 171 and cannot enter the pump body (pump chamber 2), thereby further effectively preventing the high-pressure isolation fluid in the mechanical seal from entering the pump chamber 2.
[0044] like Figure 2 and Figure 3 As shown, an isolation ring 18 is also provided inside the buffer chamber 12, and the isolation ring 18 is located between the isolation bushing 17 and the pump chamber 2. A gap 19 is provided between the first blocking part 171 and the isolation ring 18. This gap 19 provides flow space for the medium and isolation liquid entering the buffer chamber 12. The medium entering the buffer chamber 12 can flow upward through the gap 19, and the isolation liquid entering the buffer chamber 12 can flow downward through the gap 19 to avoid blockage.
[0045] In this embodiment, the end of the isolation ring 18 away from the isolation bushing 17 is fixedly connected to the inner wall of the buffer chamber 12, and the medium in the pump chamber 2 can leak from the space between the isolation ring 18 and the rotating shaft 5 into the buffer chamber 12.
[0046] Specifically, the end of the isolation ring 18 near the isolation bushing 17 has a second blocking portion 181 extending toward the mechanical sealing mechanism 9. For example... Figure 3 As shown, the second blocking part 181 is located inside the first blocking part 171 and has a gap 19 between them. Both the isolation ring 18 and the isolation bushing 17 are made of stainless steel.
[0047] In this embodiment, the outer diameter of the first blocking portion 171 is smaller than the outer diameter of the buffer cavity 12, meaning the isolation bushing 17 does not contact the outer wall surface of the buffer cavity 12, thus preventing the isolation fluid leaking from the mechanical seal mechanism 9 from being blocked by the isolation bushing 17. The inner diameter of the second blocking portion 181 is larger than the inner diameter of the buffer cavity 12, meaning the isolation ring 18 does not contact the inner wall surface of the buffer cavity 12. Both the first blocking portion 171 and the second blocking portion 181 extend along the axial direction X, which is the axial direction X of the rotating shaft 5.
[0048] like Figure 1 As shown, a volute 10 is fitted inside the pump chamber 2, surrounding the impeller 8. An inner shell 11 is fixed to the inner wall of the outer shell 1, and the volute 10 is fixedly connected to the inner shell 11. The volute 10, the inner wall of the inner shell 11, and the rotating shaft 5 form a flow channel for the medium. The inner shell 11 has a stacked structure, with two adjacent inner shells 11 stacked to form a sub-cavity accommodating the impeller 8 and the volute 10. The impeller 8 rotates within the sub-cavity, driving the medium flow.
[0049] The high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber 12 provided in this embodiment can be a horizontal or vertical centrifugal pump. It is a key pump in CCUS-related devices and has profound significance for the promotion of CCUS devices.
[0050] It should be noted that in the description of this specification, the terms "first," "second," etc., are used only for descriptive purposes and to distinguish similar objects; there is no order between them, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of this specification, unless otherwise stated, "a plurality of" means two or more.
[0051] Any numerical values cited herein include all values ranging from a lower limit to an upper limit, increasing by one unit, with at least two units between any lower and any higher value. For example, if the quantity of a component or the value of a process variable (e.g., temperature, pressure, time, etc.) is described as being from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, the purpose is to illustrate that values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 are also explicitly listed in this specification. For values less than 1, a unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1, etc. These are merely examples intended for explicit expression, and it can be assumed that all possible combinations of values listed between the minimum and maximum values are explicitly described in this specification in a similar manner.
[0052] Unless otherwise stated, all ranges include the endpoints and all numbers between them. The terms "approximately" or "about" used with ranges apply to both endpoints of the range. Thus, "approximately 20 to 30" is intended to cover "approximately 20 to approximately 30," including at least the specified endpoints.
[0053] All articles and references disclosed herein, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute included by “may” is optional.
[0054] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.
[0055] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the inventors have not considered that subject matter as part of the disclosed inventive subject matter.
Claims
1. A high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber, characterized in that, include: The outer casing has an internal pump chamber; An inlet provided on the outer casing is used for introducing a medium; An outlet provided on the outer casing is used to output the medium; A rotating shaft rotatably passes through the pump chamber; support assemblies supporting the rotating shaft are respectively provided at both ends of the outer casing; a multi-stage impeller is fixedly connected to the rotating shaft, and the multi-stage impeller is located inside the pump chamber for pumping the medium from the inlet to the outlet; A mechanical seal mechanism is disposed between the support assembly and the pump chamber. A buffer chamber is provided between the mechanical seal mechanism and the pump chamber. The buffer chamber is connected to the pump chamber and the mechanical seal mechanism respectively, and is used to collect the medium leaked in the pump chamber and the isolation liquid leaked in the mechanical seal mechanism. An exhaust pipe connected to the buffer chamber is provided with an exhaust valve; the exhaust valve controls the medium in the buffer chamber to be in a gaseous state.
2. The high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber according to claim 1, characterized in that, The support assembly includes a drive-side bearing assembly and a non-drive-side bearing assembly. One end of the rotating shaft passes through the drive-side bearing assembly and is connected to the motor. There are two mechanical seals, one located between the drive-side bearing assembly and the pump chamber, and the other located between the non-drive-side bearing assembly and the pump chamber. There are two buffer chambers.
3. The high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber according to claim 1, characterized in that, The bottom of the buffer chamber is connected to a drain pipe for draining the isolation liquid inside the buffer chamber; the drain pipe is equipped with a drain valve.
4. The high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber according to claim 3, characterized in that, The exhaust pipe is connected to the top of the buffer chamber.
5. The high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber according to claim 1, characterized in that, The buffer chamber is provided with an isolation bushing. One end of the isolation bushing is fixedly sleeved on the rotating shaft, and the other end has a first blocking part extending toward the pump chamber.
6. The high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber according to claim 5, characterized in that, The buffer cavity is also provided with an isolation ring, which is located between the isolation bushing and the pump cavity; a gap is provided between the first blocking part and the isolation ring.
7. The high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber according to claim 6, characterized in that, The end of the isolation ring furthest from the isolation bushing is fixedly connected to the inner wall of the buffer cavity.
8. The high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber according to claim 7, characterized in that, The isolation ring has a second blocking portion extending toward the mechanical sealing mechanism at one end near the isolation bushing. The second blocking portion is located inside the first blocking portion and has a gap between it and the first blocking portion.
9. The high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber according to claim 8, characterized in that, The outer diameter of the first blocking part is smaller than the outer diameter of the buffer cavity, and the inner diameter of the second blocking part is larger than the inner diameter of the buffer cavity; both the first blocking part and the second blocking part extend axially.
10. The high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber according to claim 1, characterized in that, The pump chamber is provided with a volute body sleeved outside the impeller; an inner shell is fixed to the inner wall of the outer shell, and the volute body is fixedly connected to the inner shell; the volute body, the inner wall of the inner shell, and the rotating shaft form a flow channel for the medium.