High pressure carbon dioxide delivery centrifugal pump

Abstract

The present application discloses a high-pressure carbon dioxide delivery centrifugal pump, comprising: an outer shell having a pump cavity inside; an intermediate guide body is provided in the outer shell to separate the pump cavity into a front cavity and a rear cavity; the rear cavity is connected to the downstream of the front cavity; 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 passing through the pump cavity; supporting assemblies supporting the rotating shaft are respectively provided at both ends of the outer shell; a multi-stage impeller fixedly connected to the rotating shaft, the multi-stage impeller sequentially including a first-stage impeller, a plurality of intermediate-stage impellers and a final-stage impeller from upstream to downstream, the first-stage impeller is located in the front cavity and connected to the inlet, the final-stage impeller is located in the rear cavity and connected to the outlet; the impeller size gradually decreases from the first-stage impeller to the final-stage impeller. The high-pressure carbon dioxide delivery centrifugal pump provided in this specification can improve the efficiency of the centrifugal pump.

Description

Technical Field

[0001] The present specification relates to the technical field of centrifugal pumps, and in particular to a high-pressure carbon dioxide delivery centrifugal pump. Background Art

[0002] Carbon capture, utilization and storage technology, referred to as CCUS, can effectively reduce carbon emissions from fossil energy combustion and industrial processes, and is one of the main technologies for achieving carbon neutrality. As CCUS-related devices become increasingly popular, high-pressure carbon dioxide delivery centrifugal pumps, as key pumps in CCUS-related devices, are seeing an increasing demand for applications.

[0003] Although the prior art will perform partial structural fine-tuning on general centrifugal pumps based on the physical properties of liquid carbon dioxide, liquid carbon dioxide is different from ordinary incompressible fluids. As the volume flow rate of liquid carbon dioxide inside the pump changes, the pump does not operate at the optimal efficiency point in the multi-stage impeller, and the optimal efficiency potential of the centrifugal pump has not been fully developed. Summary of the invention

[0004] After further research by the inventors, the main reason for the above problems is that, unlike conventional pumping media, low-temperature liquid CO 2 is a compressible fluid, so liquid CO 2 The density in a multi-stage high-pressure pump increases as the pressure rises. This results in the volume flow of each impeller being very different, although the pump's inlet and outlet mass flow remains constant. However, the best efficiency point of a centrifugal pump is determined by the volume flow.

[0005] In view of the above problems found in the research, an object of the present invention is to provide a high-pressure carbon dioxide delivery centrifugal pump which can improve the efficiency of the centrifugal pump.

[0006] To achieve the above-mentioned purpose, the embodiments of this specification provide a high-pressure carbon dioxide delivery centrifugal pump, comprising:

[0007] An outer shell having a pump cavity inside; an intermediate guide body is arranged inside the outer shell to separate the pump cavity into a front cavity and a rear cavity; the rear cavity is connected to the downstream of the front cavity;

[0008] An inlet provided on the outer shell, for introducing a medium;

[0009] An outlet provided on the outer shell, for outputting the medium;

[0010] A rotating shaft rotatably passes through the pump chamber; support components for supporting the rotating shaft are respectively provided at both ends of the outer shell;

[0011] A multi-stage impeller is fixedly connected to the rotating shaft, and the multi-stage impeller includes a first-stage impeller, a plurality of intermediate-stage impellers and a final-stage impeller from upstream to downstream. The first-stage impeller is located in the front cavity and is connected to the inlet, and the final-stage impeller is located in the rear cavity and is connected to the outlet; the impeller size gradually decreases from the first-stage impeller to the final-stage impeller.

[0012] As a preferred implementation, the size ratio of the m-th stage impeller to the n-th stage impeller is equal to the ratio of the medium density in the n-th stage impeller to the medium density in the m-th stage impeller, and m and n are positive integers.

[0013] As a preferred implementation, the size ratio of the last-stage impeller to the first-stage impeller is 0.75-0.9.

[0014] As a preferred implementation, the impeller size decreases proportionally from the first-stage impeller to the last-stage impeller.

[0015] As a preferred embodiment, the front cavity and the rear cavity are respectively provided with a volute body sleeved outside the impeller; the size of the volute body gradually decreases from upstream to downstream.

[0016] As a preferred embodiment, an upstream flow channel is formed between the volute body located in the front cavity and the rotating shaft; a connecting flow channel is formed between the volute body located in the rear cavity and the inner wall of the outer shell, and a downstream flow channel is formed between the volute body located in the rear cavity and the rotating shaft; and a first flow channel and a second flow channel isolated from each other are provided on the intermediate flow guide body, the first flow channel connects the upstream flow channel with the connecting flow channel, and the second flow channel connects the downstream flow channel with the outlet.

[0017] As a preferred embodiment, the high-pressure carbon dioxide delivery centrifugal pump also includes an inner casing fixed to the inner wall of the outer casing, the volute is fixedly connected to the inner casing, and the intermediate flow guide is fixedly connected to the inner casing; the connecting flow channel is formed between the outer wall of the inner casing located in the rear cavity and the inner wall of the outer casing.

[0018] As a preferred embodiment, a mouth ring is provided between the impeller and the volute body; and the size of the mouth ring gradually decreases from upstream to downstream.

[0019] As a preferred implementation, the first-stage impeller is located at an end of the front cavity away from the rear cavity, and the last-stage impeller is located at an end of the rear cavity close to the front cavity.

[0020] As a preferred implementation, the impeller located in the front chamber is oriented in the opposite direction to the impeller located in the rear chamber.

[0021] Beneficial Effects

[0022] The high-pressure carbon dioxide delivery centrifugal pump provided in this embodiment takes into account the low-temperature liquid CO 2 As a compressible fluid, liquid CO 2 In a multi-stage high-pressure pump, the density will gradually increase as the pressure rises, and the volume flow of the impeller is inversely proportional to the medium density. The optimal efficiency point is determined according to the volume flow, so the size of the impeller is designed, and the impeller size gradually decreases from the first stage to the last stage, so that each stage of the impeller can operate at the optimal efficiency point, thereby improving the efficiency of the centrifugal pump. In addition, as the impeller size decreases, the disc friction is also reduced accordingly, thereby correspondingly improving the efficiency of the pump.

[0023] 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 adopted. It should be understood that the embodiments of the present invention are not limited in scope thereby.

[0024] 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.

[0025] It should be emphasized that the term “include / comprises” 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

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description 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 creative labor.

[0027] Figure 1 This is a schematic cross-sectional structure diagram of a high-pressure carbon dioxide delivery centrifugal pump provided in this embodiment.

[0028] Description of reference numerals:

[0029] 1. Outer shell; 2. Front cavity; 3. Rear cavity; 4. Intermediate guide body; 5. Inlet; 6. Outlet; 7. Rotating shaft; 81. First-stage impeller; 82. Last-stage impeller; 83. Intermediate-stage impeller; 9. Volute; 10. Connecting flow channel; 11. First flow channel; 12. Second flow channel; 13. Inner shell; 14. Mouth ring; 15. Drive side bearing assembly; 16. Non-drive side bearing assembly. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments 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 creative work should fall within the scope of protection of the present invention.

[0031] 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 considered to be "connected to" another element, it may be directly connected to the other element or there may be another element centered thereon at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0033] See also Figure 1 The embodiment of the present application provides a high-pressure carbon dioxide delivery centrifugal pump, comprising: an outer shell 1, an inlet 5, an outlet 6, a rotating shaft 7 and a multi-stage impeller.

[0034] The outer shell 1 is a cylindrical structure. The outer shell 1 has a pump cavity inside. The outer shell 1 is provided with an intermediate guide body 4 that divides the pump cavity into a front cavity 2 and a rear cavity 3. The rear cavity 3 is connected to the downstream of the front cavity 2. An inlet 5 is provided on the outer shell 1 for introducing a medium. An outlet 6 is provided on the outer shell 1 for outputting the medium. A rotating shaft 7 is rotatably provided through the pump cavity. Support assemblies for supporting the rotating shaft 7 are provided at both ends of the outer shell 1. A multi-stage impeller is fixedly connected to the rotating shaft 7, and the multi-stage impeller includes a first-stage impeller 81, a plurality of intermediate-stage impellers 83 and a final-stage impeller 82 from upstream to downstream. The first-stage impeller 81 is located in the front cavity 2 and is connected to the inlet 5, and the final-stage impeller 82 is located in the rear cavity 3 and is connected to the outlet 6. From the first-stage impeller 81 to the final-stage impeller 82, the impeller size gradually decreases.

[0035] It should be noted that the high-pressure carbon dioxide delivery centrifugal pump is mainly used to transport liquid CO 2, that is, the above medium is liquid CO 2 Of course, the high-pressure carbon dioxide delivery centrifugal pump can also be used to deliver other compressible fluids to improve efficiency. The impeller size in this application mainly refers to the outer diameter of the impeller. The implementation method of this application does not limit the number of impellers, and multi-stage impellers can be provided in the front cavity 2 and the rear cavity 3.

[0036] In a preferred embodiment, in order to make each stage of impeller operate at the optimal efficiency point, the operating point (volume flow rate) of each stage of impeller and flow channel can be calculated and allocated in advance, and the impeller size can be designed with the operating point as the optimal efficiency point, so as to ensure that the pump has extremely high hydraulic efficiency. The density of the medium in the centrifugal pump changes, so the volume flow rate of the pump changes, and the medium density and volume flow rate are inversely proportional. For example, if the ratio of the medium density in the two impellers is a, then in order to make each impeller operate at the optimal efficiency point, the geometric ratio of the two impellers is preferably 1 / a. That is, the size ratio of the mth stage impeller and the nth stage impeller is equal to the ratio of the medium density in the nth stage impeller to the medium density in the mth stage impeller, and m and n are positive integers.

[0037] In a specific embodiment, the size ratio of the final stage impeller 82 to the first stage impeller 81 is 0.75-0.9, that is, the ratio of the medium density at the inlet 5 to the medium density at the outlet 6 is 0.75-0.9. Of course, the size ratio of the two impellers is not necessarily related only to the medium density, but also to other parameters of the pump (such as pressure, temperature), and multiple parameters can be comprehensively referred to during specific design.

[0038] In one embodiment, the impeller size decreases proportionally from the first-stage impeller 81 to the last-stage impeller 82. From the perspective of hydraulic development, the impellers of each stage can be considered as similar hydraulic models, which greatly reduces the development cost and shortens the development cycle.

[0039] In this embodiment, the front chamber 2 and the rear chamber 3 are respectively provided with a volute 9 sleeved outside the impeller. An upstream flow channel is formed between the volute 9 located in the front chamber 2 and the rotating shaft 7, and a downstream flow channel is formed between the volute 9 located in the rear chamber 3 and the rotating shaft 7. As the outer diameter of the secondary impeller decreases, the size of the volute 9 gradually decreases from upstream to downstream to match the change of the impeller, so that the flow channel design meets the requirements.

[0040] like Figure 1 As shown, a connecting flow channel 10 is formed between the volute 9 located in the rear cavity 3 and the inner wall of the outer shell 1. The intermediate flow guide 4 is provided with a first flow channel 11 and a second flow channel 12 which are isolated from each other, that is, the first channel and the second channel are not connected to each other. The first flow channel 11 connects the upstream flow channel with the connecting flow channel 10, and the second flow channel 12 connects the downstream flow channel with the output port 6.

[0041] Specifically, the high-pressure carbon dioxide delivery centrifugal pump further includes an inner shell 13 fixed to the inner wall of the outer shell 1, and the front chamber 2 and the rear chamber 3 are both provided with the inner shell 13. The volute 9 is fixedly connected to the inner shell 13, and the two sides of the intermediate flow guide 4 are respectively fixedly connected to the inner shell 13 located in the front chamber 2 and the rear chamber 3. The connecting flow channel 10 is formed between the outer wall of the inner shell 13 located in the rear chamber 3 and the inner wall of the outer shell 1, the upstream flow channel is formed between the volute 9 located in the front chamber 2, the inner wall of the inner shell 13 and the rotating shaft 7, and the downstream flow channel is formed between the volute 9 located in the rear chamber 3, the inner wall of the inner shell 13 and the rotating shaft 7.

[0042] In this embodiment, a mouth ring 14 is provided between the impeller and the volute 9. As the outer diameter of the secondary impeller decreases, the size of the mouth ring 14 gradually decreases from upstream to downstream to maintain axial force balance. The reduction in the size of the mouth ring 14 can reduce the leakage of the mouth ring 14 and improve the efficiency of the pump.

[0043] like Figure 1 As shown, the support assembly is a driving side bearing assembly 15 and a non-driving side bearing assembly 16, and one end of the rotating shaft 7 passes through the driving side bearing assembly 15 and is connected to the motor. The front cavity 2 and the rear cavity 3 respectively have multi-stage impellers, and the inner casing 13 is a stacking structure. Two adjacent inner casings 13 are stacked to form a sub-cavity for accommodating the impeller and the volute body 9. The impeller rotates in the sub-cavity to drive the fluid to flow.

[0044] Specifically, the inlet 5 is arranged at one end of the outer shell 1. The first-stage impeller 81 is located at one end of the front chamber 2 away from the rear chamber 3, and the last-stage impeller 82 is located at one end of the rear chamber 3 close to the front chamber 2. Furthermore, the direction of the impeller located in the front chamber 2 is opposite to the direction of the impeller located in the rear chamber 3, that is, the impellers in the front chamber 2 and the rear chamber 3 are opposite to each other. Correspondingly, the fluid flow directions in the front chamber 2 and the rear chamber 3 are opposite. In this way, the present embodiment adopts a back-to-back impeller arrangement, and the axial force is balanced by the impellers arranged on both sides, thereby ensuring the continuous and stable operation of the pump body and improving the efficiency of the pump. In addition, the design of the high-efficiency guide vane flow channel also ensures the high efficiency of the pump.

[0045] The high-pressure carbon dioxide delivery centrifugal pump provided in this embodiment adopts a horizontal centerline installation structure, and the intermediate guide body 4 radially divides the outer shell 1 to form a front cavity 2 and a rear cavity 3, and the impellers of the front cavity 2 and the rear cavity 3 are arranged back to back. In the design of the flow channel and the impeller, the primary consideration is to improve the pump efficiency and minimize the liquid CO 2 Energy loss when flowing in the pump body. Specifically, considering the low temperature liquid CO 2 As a compressible fluid, liquid CO 2The density in a multi-stage high-pressure pump will gradually increase as the pressure rises, and the volume flow of the impeller is inversely proportional to the medium density. The optimal efficiency point is determined according to the volume flow. Therefore, the size of the impeller is designed, and the impeller size gradually decreases from the first-stage impeller 81 to the last-stage impeller 82, so that each stage of the impeller can operate at the optimal efficiency point, thereby improving the efficiency of the centrifugal pump. In addition, as the impeller size decreases, the disc friction is also reduced accordingly, thereby correspondingly improving the efficiency of the pump.

[0046] It should be noted that, in the description of this specification, the terms "first", "second", etc. are only used for descriptive purposes and to distinguish similar objects. There is no order of precedence between the two, and they cannot be understood as indicating or implying relative importance. In addition, in the description of this specification, unless otherwise specified, the meaning of "plurality" is two or more.

[0047] Any numerical value cited herein includes all values ​​of lower and upper values ​​that increase by one unit from the lower limit to the upper limit, and there is at least a two-unit interval between any lower value and any higher value. For example, if the value of the quantity of a component or a process variable (such as temperature, pressure, time, etc.) is set forth to be from 1 to 90, preferably from 20 to 80, and 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 the 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 that are intended to be clearly expressed, and it can be considered that all possible combinations of numerical values ​​listed between the lowest value and the highest value are clearly set forth in the specification in a similar manner.

[0048] Unless otherwise indicated, all ranges include the endpoints and all numbers between the endpoints. "About" or "approximately" used with a range 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.

[0049] All articles and references disclosed, including patent applications and publications, are incorporated herein by reference for all purposes. The term "consisting essentially of..." to describe a combination should include the identified elements, ingredients, parts or steps and other elements, ingredients, parts or steps that do not substantially affect the basic novel characteristics of the combination. The use of the terms "comprising" or "including" to describe a combination of elements, ingredients, parts or steps herein also contemplates embodiments that consist essentially of these elements, ingredients, parts or steps. By using the term "may", it is intended to indicate that any attribute described that "may" include is optional.

[0050] 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 "one" or "an" used to describe an element, ingredient, part or step is not intended to exclude other elements, ingredients, parts or steps.

[0051] 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 should be determined with reference to the appended claims and the full scope of equivalents possessed by such claims. 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 in the preceding claims is not intended to be a waiver of the subject matter, nor should it be considered that the inventors did not consider the subject matter to be part of the disclosed inventive subject matter.

Claims

1. A high-pressure liquid carbon dioxide delivery centrifugal pump, characterized in that: include: An outer housing having a pump chamber therein; The outer shell is provided with an intermediate guide body which divides the pump cavity into a front cavity and a rear cavity; The rear chamber is connected to the downstream of the front chamber; 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 components for supporting the rotating shaft are respectively provided at both ends of the outer shell; A multi-stage impeller fixedly connected to the rotating shaft, the multi-stage impeller comprises a first-stage impeller, a plurality of intermediate-stage impellers and a final-stage impeller from upstream to downstream, the first-stage impeller is located in the front chamber and communicated with the inlet, the final-stage impeller is located in the rear chamber and communicated with the outlet; the impeller size gradually decreases from the first-stage impeller to the final-stage impeller; the size ratio of the m-th stage impeller and the n-th stage impeller is equal to the ratio of the medium density in the n-th stage impeller to the medium density in the m-th stage impeller, and m and n are positive integers; the front chamber and the rear chamber are respectively provided with a volute body sleeved outside the impeller; the size of the volute body gradually decreases from upstream to downstream; a mouth ring is provided between the impeller and the volute body; the size of the mouth ring gradually decreases from upstream to downstream.

2. The high-pressure liquid carbon dioxide delivery centrifugal pump according to claim 1, characterized in that: The size ratio of the final stage impeller to the first stage impeller is 0.75-0.

9.

3. The high-pressure liquid carbon dioxide delivery centrifugal pump according to claim 1, characterized in that: The impeller size decreases proportionally from the first-stage impeller to the last-stage impeller.

4. The high-pressure liquid carbon dioxide delivery centrifugal pump according to claim 1, characterized in that: An upstream flow channel is formed between the volute body located in the front cavity and the rotating shaft; a connecting flow channel is formed between the volute body located in the rear cavity and the inner wall of the outer shell, and a downstream flow channel is formed between the volute body located in the rear cavity and the rotating shaft; a first flow channel and a second flow channel separated from each other are provided on the intermediate flow guide body, the first flow channel connects the upstream flow channel with the connecting flow channel, and the second flow channel connects the downstream flow channel with the outlet.

5. The high-pressure liquid carbon dioxide delivery centrifugal pump according to claim 4, characterized in that: It also includes an inner shell fixed to the inner wall of the outer shell, the volute is fixedly connected to the inner shell, and the intermediate flow guide is fixedly connected to the inner shell; the connecting flow channel is formed between the outer wall of the inner shell located in the rear cavity and the inner wall of the outer shell.

6. The high-pressure liquid carbon dioxide delivery centrifugal pump according to claim 1, characterized in that: The first-stage impeller is located at one end of the front cavity away from the rear cavity, and the last-stage impeller is located at one end of the rear cavity close to the front cavity.

7. The high-pressure liquid carbon dioxide delivery centrifugal pump according to claim 6, characterized in that: The impeller located in the front chamber has an opposite direction to the impeller located in the rear chamber.

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