Carbon dioxide high-pressure centrifugal pump with sealing buffer cavity

Abstract

The invention discloses a carbon dioxide high-pressure centrifugal pump with a sealing buffer cavity, and relates to the field of high-pressure pumps. The inlet is formed in the outer shell and is used for introducing a medium; the outlet is formed in the outer shell and used for outputting a medium; the rotating shaft rotatably penetrates through the pump cavity; supporting assemblies for supporting the rotating shaft are arranged at the two ends of the outer shell respectively; the rotating shaft is fixedly connected with multiple stages of impellers located in the pump cavity and used for pumping media from the inlet to the outlet. The mechanical sealing mechanism is arranged between the supporting assembly and the pump cavity, a buffering cavity is formed between the mechanical sealing mechanism and the pump cavity, and the buffering cavity communicates with the pump cavity and the mechanical sealing mechanism and is used for collecting media leaked in the pump cavity and spacer fluid leaked in the mechanical sealing mechanism; the exhaust pipeline is connected with the buffer cavity, and an exhaust valve is arranged on the exhaust pipeline; and the medium in the buffer cavity is controlled to be gaseous through the exhaust valve. The centrifugal pump can efficiently convey liquid carbon dioxide and effectively prevent high-pressure spacer fluid in the mechanical seal from entering the pump cavity.

Description

Technical Field

[0001] The present invention relates to the technical field of high-pressure pumps, and in particular to a high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber. Background Art

[0002] Carbon capture, utilization, and storage (CCUS) technology can effectively reduce carbon emissions from fossil fuel combustion and industrial processes. As CCUS-related devices become increasingly prevalent, demand for high-pressure carbon dioxide transfer centrifugal pumps, key pumps in CCUS-related systems, is steadily increasing.

[0003] However, due to the extremely poor lubricity of carbon dioxide as a medium, users and pump manufacturers have been troubled when choosing a mechanical seal flushing solution for high-pressure carbon dioxide transfer centrifugal pumps. This is especially true under working conditions where the medium cannot be contaminated, as there is an inevitable risk that the high-pressure isolation fluid in the mechanical seal will enter the pump cavity and contaminate the medium during operation. Summary of the Invention

[0004] In view of the deficiencies in the prior art, one purpose of this specification is to provide a carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber, which can efficiently transport liquid carbon dioxide and effectively prevent the high-pressure isolation fluid in the mechanical seal from entering the pump chamber.

[0005] To achieve the above objectives, embodiments of the present specification provide a method of: 1. A high-pressure centrifugal pump for carbon dioxide with a sealed buffer chamber, comprising: an outer housing having a pump cavity therein; An inlet provided on the outer shell, for introducing a medium; An outlet provided on the outer shell, for outputting 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 shell; a multi-stage impeller is fixedly connected to the rotating shaft, and the multi-stage impeller is located in the pump chamber and is used to pump the medium from the inlet to the outlet; A mechanical seal mechanism is provided between the support assembly and the pump chamber, wherein a buffer chamber is provided between the mechanical seal mechanism and the pump chamber, the buffer chamber being in communication with the pump chamber and the mechanical seal mechanism, respectively, and being used to collect the medium leaked from the pump chamber and the isolation liquid leaked from the mechanical seal mechanism; An exhaust pipe connected to the buffer chamber is provided with an exhaust valve; the medium in the buffer chamber is controlled to be in a gaseous state by the exhaust valve.

[0006] As a preferred embodiment, the support assembly includes a driving side bearing assembly and a non-driving side bearing assembly, and one end of the rotating shaft passes through the driving side bearing assembly and is connected to the motor; the number of the mechanical sealing mechanisms is two, one is located between the driving side bearing assembly and the pump chamber, and the other is located between the non-driving side bearing assembly and the pump chamber; the number of the buffer chambers is two.

[0007] As a preferred embodiment, the bottom of the buffer cavity is connected to a drain pipe for discharging the isolation liquid in the buffer cavity; and a drain valve is provided on the drain pipe.

[0008] As a preferred embodiment, the exhaust pipe is connected to the top of the buffer chamber.

[0009] As a preferred embodiment, an isolation bushing is provided in the buffer cavity, one end of the isolation bushing is fixedly sleeved on the rotating shaft, and the other end of the isolation bushing has a first blocking portion extending toward the pump cavity.

[0010] As a preferred embodiment, an isolation ring is further provided in the buffer cavity, and the isolation ring is located between the isolation bushing and the pump cavity; and a gap is provided between the first blocking portion and the isolation ring.

[0011] As a preferred embodiment, one end of the isolation ring away from the isolation bushing is fixedly connected to the inner wall surface of the buffer cavity.

[0012] As a preferred embodiment, the isolation ring has a second blocking portion at one end close to the isolation bushing extending toward the mechanical sealing mechanism, and the second blocking portion is located inside the first blocking portion and a gap is provided between the second blocking portion and the first blocking portion.

[0013] As a preferred embodiment, the outer diameter of the first blocking portion is smaller than the outer diameter of the buffer cavity, and the inner diameter of the second blocking portion is larger than the inner diameter of the buffer cavity; both the first blocking portion and the second blocking portion extend in the axial direction.

[0014] As a preferred embodiment, a volute is provided in the pump chamber and is sleeved outside the impeller; an inner casing is fixed to the inner wall of the outer casing, and the volute is fixedly connected to the inner casing; a flow channel for the medium is formed between the volute, the inner wall of the inner casing and the rotating shaft. Beneficial effects

[0015] The carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber provided in this embodiment can collect the medium leaked from the pump chamber and the isolation liquid leaked from the mechanical seal mechanism by setting a buffer chamber between the pump chamber and the mechanical seal mechanism, and an exhaust pipe is set to be connected to the buffer chamber, and the pressure in the buffer chamber is controlled by the exhaust valve on the exhaust pipe, so that the medium entering the buffer chamber changes from liquid to gas. Since the buffer chamber contains not a liquid medium but a gaseous medium, even if the isolation liquid of the mechanical seal mechanism leaks, it will not enter the interior of the pump body (i.e., the pump chamber). The leaked isolation liquid will accumulate in the lower part of the buffer chamber. When the rehydration cycle of the mechanical seal mechanism expires, the buffer chamber can be drained while the mechanical seal mechanism is being rehydrated, thereby ensuring the normal and stable operation of the pump. Therefore, the carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber provided in this application can efficiently transport liquid carbon dioxide and can effectively prevent the high-pressure isolation liquid in the mechanical seal from entering the pump chamber.

[0016] With reference to the following description and the accompanying drawings, the specific embodiments of the present invention are disclosed in detail, indicating the manner in which the principles of the present invention can be employed. It should be understood that the embodiments of the present invention are not limited in scope thereby.

[0017] Features described and / or illustrated with respect to 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.

[0018] It should be emphasized that the term "include / comprising" when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 paying any creative labor.

[0020] Figure 1 Schematic diagram of the cross-sectional structure of a carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber provided in this embodiment; Figure 2 for Figure 1 Schematic diagram of the enlarged structure at A in the middle; Figure 3 for Figure 2 Schematic diagram of the structure of the isolation bushing and isolation ring on one side.

[0021] Description of reference numerals: 1. Outer casing; 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 casing; 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. Gap; X, axial direction. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0023] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be another element centered thereon. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be another element centered thereon. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] See also Figures 1 to 3 The embodiment of the present application provides a carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber 12 , comprising: an outer shell 1 , an inlet 3 , an outlet 4 , a rotating shaft 5 , a mechanical sealing mechanism 9 and an exhaust pipe 13 .

[0026] Among them, the outer shell 1 has a pump chamber 2 inside. The inlet 3 is arranged on the outer shell 1 for introducing the medium. The outlet 4 is arranged on the outer shell 1 for outputting the medium. The rotating shaft 5 is rotatably passed through the pump chamber 2. Support assemblies for supporting the rotating shaft 5 are respectively provided at both ends of the outer shell 1. A multi-stage impeller 8 is fixedly connected to the rotating shaft 5, and the multi-stage impeller 8 is located in the pump chamber 2 and is used to pump the medium from the inlet 3 to the outlet 4. The mechanical seal mechanism 9 is arranged between the support assembly and the pump chamber 2. A buffer chamber 12 is provided between the mechanical seal mechanism 9 and the pump chamber 2. The buffer chamber 12 is respectively connected to the pump chamber 2 and the mechanical seal mechanism 9, and is used to collect the medium leaked from the pump chamber 2 and the isolation liquid leaked from the mechanical seal mechanism 9. The exhaust pipe 13 is connected to the buffer chamber 12. An exhaust valve 14 is provided on the exhaust pipe 13. The medium in the buffer chamber 12 is controlled to be gaseous by the exhaust valve 14.

[0027] It should be noted that the high-pressure carbon dioxide centrifugal pump with a sealed buffer chamber 12 is primarily used for transporting liquid CO2, i.e., the medium is liquid CO2. Of course, the 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.

[0028] Due to the extremely poor lubricity of carbon dioxide, the only mechanical seal flushing solution available was Plan 53B, which relies on barrier fluid for lubrication of the dynamic and static rings. However, since Plan 53B's high-pressure barrier fluid inevitably risks entering pump chamber 2 and contaminating the medium during operation, this solution is unsuitable for pumping carbon dioxide in applications where contamination is unacceptable.

[0029] To this end, the carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber 12 provided in this embodiment can separate the easily vaporized pumping medium from the isolation liquid of the mechanical seal mechanism 9 by setting the buffer chamber 12 between the pump chamber 2 and the mechanical seal mechanism 9, thereby ensuring that the pumping medium is not contaminated, and can collect the medium leaked in the pump chamber 2 and the isolation liquid leaked in the mechanical seal mechanism 9, and an exhaust pipe 13 is set to be connected to the buffer chamber 12, and the pressure in the buffer chamber 12 is controlled by the exhaust valve 14 on the exhaust pipe 13, so that the medium entering the buffer chamber 12 changes from liquid to gas. Since the medium in the buffer chamber 12 is not a liquid medium but a gaseous medium, even if the isolation liquid of the mechanical seal mechanism 9 leaks, it will not enter the interior of the pump body (i.e., the pump chamber 2). The leaked isolation liquid will accumulate in the lower part of the buffer chamber 12. When the rehydration cycle of the mechanical seal mechanism 9 expires, the buffer chamber 12 can be drained while the mechanical seal mechanism 9 is being rehydrated, thereby ensuring the normal and stable operation of the pump.

[0030] 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 within the mechanical seal from entering the pump chamber 2. Furthermore, unlike the mechanical seals used in conventional centrifugal pumps for transporting carbon dioxide, the mechanical seal mechanism 9 required by the present invention requires a common mechanical seal structure and can be used with a commonly available commercial isolation fluid, significantly reducing design and operating costs.

[0031] 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. Two mechanical seals 9 are provided: one between the drive-side bearing assembly 6 and the pump chamber 2, and the other between the non-drive-side bearing assembly 7 and the pump chamber 2. Accordingly, two buffer chambers 12 are provided. Each buffer chamber 12 is generally annular in shape.

[0032] like Figure 1 As shown, a drain pipe 15 is connected to the bottom of the buffer chamber 12 for draining the barrier liquid within the buffer chamber 12. A drain valve 16 is provided on the drain pipe 15. When the barrier liquid collected in the buffer chamber 12 needs to be drained, the drain valve 16 is opened. The barrier liquid entering the buffer chamber 12 can be recycled after discharge, reducing barrier liquid consumption.

[0033] Specifically, the exhaust pipe 13 is connected to the top of the buffer chamber 12 to prevent the isolation liquid in the buffer chamber 12 from entering the exhaust pipe 13 .

[0034] like Figure 1 and Figure 2 As shown, an isolation sleeve 17 is provided within the buffer chamber 12. One end of the isolation sleeve 17 is fixedly mounted on the rotating shaft 5, and the other end has a first blocking portion 171 extending toward the pump chamber 2. The extension direction of the first blocking portion 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 injected isolation fluid is blocked by the first blocking portion 171 and cannot enter the pump body (inside the pump chamber 2), thereby further effectively preventing the high-pressure isolation fluid in the mechanical seal from entering the pump chamber 2.

[0035] like Figure 2 and Figure 3 As shown, an isolation ring 18 is further provided in the buffer chamber 12, and is located between the isolation bushing 17 and the pump chamber 2. A gap 19 is provided between the first blocking portion 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 this gap 19, and the isolation liquid entering the buffer chamber 12 can flow downward through this gap 19 to avoid blockage.

[0036] In this embodiment, the end of the isolation ring 18 away from the isolation bushing 17 is fixedly connected to the inner wall surface of the buffer chamber 12 , and the medium in the pump chamber 2 can leak into the buffer chamber 12 from the space between the isolation ring 18 and the rotating shaft 5 .

[0037] Specifically, the end of the isolation ring 18 close to the isolation bushing 17 has a second blocking portion 181 extending toward the mechanical sealing mechanism 9. Figure 3 As shown, the second blocking portion 181 is located inside the first blocking portion 171 and a gap 19 is provided between the second blocking portion 181 and the first blocking portion 171. The isolation ring 18 and the isolation bushing 17 are both made of stainless steel.

[0038] In this embodiment, the outer diameter of the first blocking portion 171 is smaller than the outer diameter of the buffer cavity 12, meaning that the isolation bushing 17 does not contact the outer wall of the buffer cavity 12. Thus, any isolation fluid leaking from the mechanical seal 9 is not 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 that the isolation ring 18 does not contact the inner wall of the buffer cavity 12. Both the first blocking portion 171 and the second blocking portion 181 extend along the axial direction X, which corresponds to the axial direction X of the rotating shaft 5.

[0039] like Figure 1 As shown, the pump chamber 2 is equipped with a volute 10 that is sleeved over the impeller 8. An inner casing 11 is fixed to the inner wall of the outer casing 1, with the volute 10 fixedly connected to the inner casing 11. The medium flow path is formed between the volute 10, the inner wall of the inner casing 11, and the rotating shaft 5. The inner casings 11 are stacked, with two adjacent inner casings 11 stacked together to form a sub-chamber that accommodates the impeller 8 and volute 10. The impeller 8 rotates within the sub-chamber, driving the medium flow.

[0040] The carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber 12 provided in this embodiment can be a horizontal centrifugal pump or a vertical centrifugal pump. It is a key pump in CCUS-related devices and has far-reaching significance for the promotion of CCUS devices and the national energy conservation and emission reduction strategy.

[0041] It should be noted that, in the description of this specification, the terms "first," "second," etc., are used solely for descriptive purposes and to distinguish similar objects. There is no order of precedence between the two, nor should they be understood to indicate or imply relative importance. Furthermore, in the description of this specification, unless otherwise specified, "plurality" means two or more.

[0042] Any numerical value cited herein includes all values ​​of the lower and upper values ​​in increments of one unit from the lower value to the upper value, provided that there is at least a two-unit interval between any lower value and any higher value. For example, if the value of a component quantity or process variable (e.g., temperature, pressure, time, etc.) is stated to be from 1 to 90, preferably from 20 to 80, and more preferably from 30 to 70, it is intended to illustrate that values ​​such as 15 to 85, 22 to 68, 43 to 51, 30 to 32, etc. are also explicitly listed in this specification. For values ​​less than 1, one unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1. These are merely examples intended to be clearly stated, and it is to be understood that all possible combinations of the values ​​listed between the minimum and maximum values ​​are explicitly stated in this specification in a similar manner.

[0043] Unless otherwise indicated, all ranges include the endpoints and all numbers between the endpoints. When used with a range, "about" or "approximately" applies to both endpoints of the range. Thus, "about 20 to 30" is intended to cover "about 20 to about 30," including at least the specified endpoints.

[0044] All articles and references disclosed herein, including patent applications and publications, are incorporated herein by reference for all purposes. The term "consisting essentially of..." when describing a combination should include the identified elements, ingredients, components, or steps and other elements, ingredients, components, or steps that do not materially affect the basic novel characteristics of the combination. The use of the terms "comprising" or "including" to describe a combination of elements, ingredients, components, or steps herein also contemplates embodiments consisting essentially of these elements, ingredients, components, or steps. By using the term "may," it is intended to indicate that any attribute described as "may" be optional.

[0045] Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure of "a" or "an" to describe an element, ingredient, part or step is not intended to exclude other elements, ingredients, parts or steps.

[0046] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the appended claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein from the foregoing claims is not intended to be a disclaimer of such subject matter, nor should it be assumed that the inventors did not consider such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber, characterized in that: include: an outer housing having a pump cavity therein; An inlet provided on the outer shell, for introducing a medium; An outlet provided on the outer shell, for outputting 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 shell; a multi-stage impeller is fixedly connected to the rotating shaft, and the multi-stage impeller is located in the pump chamber and is used to pump the medium from the inlet to the outlet; A mechanical seal mechanism is provided between the support assembly and the pump chamber, wherein a buffer chamber is provided between the mechanical seal mechanism and the pump chamber, the buffer chamber being in communication with the pump chamber and the mechanical seal mechanism, respectively, and being used to collect the medium leaked from the pump chamber and the isolation liquid leaked from the mechanical seal mechanism; An exhaust pipe connected to the buffer chamber is provided with an exhaust valve; the medium in the buffer chamber is controlled to be in a gaseous state by the exhaust valve.

2. The carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber according to claim 1, characterized in that: The support assembly includes a driving side bearing assembly and a non-driving side bearing assembly, and one end of the rotating shaft passes through the driving side bearing assembly and is connected to the motor; the number of the mechanical sealing mechanisms is two, one is located between the driving side bearing assembly and the pump chamber, and the other is located between the non-driving side bearing assembly and the pump chamber; the number of the buffer chambers is two.

3. The carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber according to claim 1, characterized in that: The bottom of the buffer cavity is connected to a drainage pipe for discharging the isolation liquid in the buffer cavity; a drainage valve is provided on the drainage pipe.

4. The carbon dioxide high-pressure 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 carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber according to claim 1, characterized in that: An isolation bushing is provided in the buffer cavity. One end of the isolation bushing is fixedly sleeved on the rotating shaft, and the other end of the isolation bushing has a first blocking portion extending toward the pump cavity.

6. The carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber according to claim 5, characterized in that: An isolation ring is further provided in the buffer cavity, and the isolation ring is located between the isolation bushing and the pump cavity; a gap is provided between the first blocking portion and the isolation ring.

7. The carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber according to claim 6, characterized in that: One end of the isolation ring away from the isolation bushing is fixedly connected to the inner wall surface of the buffer cavity.

8. The carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber according to claim 7, characterized in that: One end of the isolation ring close to the isolation bushing has a second blocking portion extending toward the mechanical sealing mechanism. The second blocking portion is located inside the first blocking portion and a gap is provided between the second blocking portion and the first blocking portion.

9. The carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber according to claim 8, characterized in that: The outer diameter of the first blocking portion is smaller than the outer diameter of the buffer cavity, and the inner diameter of the second blocking portion is larger than the inner diameter of the buffer cavity; both the first blocking portion and the second blocking portion extend in the axial direction.

10. The carbon dioxide high-pressure centrifugal pump with a sealed buffer chamber according to claim 1, characterized in that: The pump chamber is provided with a volute sleeved outside the impeller; an inner casing is fixed to the inner wall of the outer casing, and the volute is fixedly connected to the inner casing; a flow channel for the medium is formed between the volute, the inner wall of the inner casing and the rotating shaft.

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