Supercritical CO2 expander based on integrated cooling system

Abstract

The present invention provides a supercritical carbon dioxide expander based on an integrated cooling system, comprising: a rotor part, comprising: a turbine, a main shaft, and a dry gas sealing moving part; a casing part, arranged outside the rotor part, comprising: a volute, a dry gas sealing static part, arranged around the dry gas sealing moving part, and fixedly connected to the sealed casing outside; a heat-insulating casing, forming a first annular gap between the casing and the dry gas sealing moving part, a second annular gap between the casing and the main shaft, and a third annular gap between the casing and the turbine; and a cooling ring sleeve, arranged around the surface of the heat-insulating casing, used for introducing a certain flow of high-pressure and low-temperature supercritical carbon dioxide, and performing flow heat exchange in the cooling ring sleeve, and a sealed gas channel, used for inputting the carbon dioxide discharged from the cooling ring sleeve outlet and adjusted by the sealer control system into the first annular gap from the sealed gas channel inlet, and then flowing through the second annular gap and then flowing to the third annular gap, so as to realize simultaneous series cooling of the rotor part and the casing part.

Description

Technical Field

[0001] The present disclosure relates to the technical field of turbine power generation technology, and in particular to a supercritical carbon dioxide expander based on an integrated cooling system. Background Art

[0002] Supercritical carbon dioxide (SCO2) turbine power generation technology is a new type of power generation technology that uses supercritical CO2 as a working fluid to convert thermal energy into electrical energy through turbine machinery. It is suitable for power generation or power conversion from a variety of heat sources and has broad application prospects in the fields of thermal power, nuclear power, and solar power generation. SCO2 power generation equipment has the characteristics of high energy conversion efficiency and compact structure, and its advantages have attracted widespread attention.

[0003] The SCO2 expander has the characteristics of high speed, high temperature, high energy density and high compactness. When the high-temperature and high-pressure working fluid flows through the turbine, the heat will be transferred axially through the rotor and the casing. Since the SCO2 expander is very compact, the distance between the turbine and seals, bearings, motors and other components is very short, and high temperature can easily cause them to fail and be damaged. Therefore, it must be equipped with a cooling and heat insulation system to achieve high-temperature heat insulation of the turbine in a limited space.

[0004] At present, there are data indicating that an air injection pipeline is added between the turbine and the seal, and the seal and bearing are cooled by the air injection system (such as: patent "A turbine generator set with supercritical carbon dioxide as working fluid", announcement number CN106014509A), but the additional air injection system and the corresponding temperature and pressure regulating equipment make the turbine unit structure more complicated, and also increase the main shaft length to a certain extent, affecting its vibration performance. In addition, the patent "Supercritical Carbon Dioxide Brayton Cycle Power Component Cooling Sealing and Insulation System" (Announcement No. CN208564662U) proposes a structure for cooling and isolating the compressor impeller back leakage gas for the coaxial integrated structure of the compressor-motor-expander: the compressor leakage gas reaches the isolation ring cavity at the back of the expander impeller after passing through the annular gap between the casing and the main shaft, and is discharged after mixing with the expander leakage gas, which plays a cooling and isolating role. Although there is no additional cooling system, which reduces the complexity of the unit, the cooling effect is difficult to ensure because the flow rate of the compressor leakage gas is small. For supercritical carbon dioxide turbines with working fluids above 200°C, it cannot meet the cooling requirements. Moreover, the above-mentioned existing technical solutions can only realize the cooling of the main shaft, and cannot meet the cooling requirements of the casing at the same time. Therefore, for the compact supercritical carbon dioxide turbine, it is urgent to propose an efficient, simple and compact cooling and insulation method that can simultaneously meet the thermal conductivity problems of the rotor and the casing.

[0005] Public Content

[0006] 1. Technical issues to be resolved

[0007] Based on the above problems, the present disclosure provides a supercritical carbon dioxide expander based on an integrated cooling system to alleviate technical problems in the prior art such as the complex structure of the turbine unit when cooling the seals and bearings through the gas injection system, or the poor cooling effect when using the compressor leakage gas for cooling and isolation.

[0008] (II) Technical solution

[0009] The present invention provides a supercritical carbon dioxide expander based on an integrated cooling system, comprising: a rotor part, including: a turbine; a main shaft, one end of which is connected to the turbine; and a dry gas sealing moving component, which is arranged on the other end of the main shaft; a casing part, which is arranged around the rotor part, and comprises: a volute, which is arranged on the periphery of the turbine; a dry gas sealing static component, which is arranged around the dry gas sealing moving component and is fixedly connected to the sealing casing outside; a heat-insulating casing, which is arranged between the volute and the sealing casing, and forms a first annular gap with the dry gas sealing moving component, a second annular gap with the main shaft, and a third annular gap with the turbine; and a cooling ring sleeve, which is arranged around the surface of the sealing casing. , which is used to transport carbon dioxide and cool the sealed casing. A cooling ring inlet and a cooling ring outlet are arranged at relative positions. The cooling ring inlet is used to introduce a certain flow of high-pressure and low-temperature supercritical carbon dioxide from the compressor side or other suitable positions of the system, flow heat exchange inside the cooling ring, and discharge from the cooling ring outlet after cooling the sealed casing; and a sealed air channel is used to input the carbon dioxide discharged from the cooling ring outlet and adjusted by the sealer control system into the first annular gap from the sealed air channel inlet, and then flow through the second annular gap and then flow to the third annular gap, so as to realize simultaneous series cooling of the rotor part and the casing part.

[0010] In the embodiment of the present disclosure, the sealing gas control system includes: a storage tank connected to the outlet of the cooling ring sleeve, used to stabilize the pressure of the discharged carbon dioxide fluid; a pressure regulating module, used to regulate the pressure of the carbon dioxide fluid, including three fluid pipelines arranged in parallel, any two of which are respectively provided with a throttling and pressure reducing device and a booster pump, and each fluid pipeline is respectively provided with a stop valve; a heat exchanger, used to adjust the temperature of the carbon dioxide according to the cooling requirements and then flow into the first annular gap of the expander through the inlet of the sealing gas channel; and a flow regulating valve, used to regulate the flow of the sealing gas.

[0011] In the disclosed embodiment, the turbine comprises: any one of a centrifugal impeller and an axial impeller.

[0012] In the disclosed embodiment, the turbine structure is a single-stage structure or a multi-stage structure.

[0013] In the disclosed embodiment, the sealed casing and the dry gas sealed static component are connected together by bolt fastening components.

[0014] In the disclosed embodiment, the cooling ring is arranged on the surface of the sealing casing.

[0015] In an embodiment of the present disclosure, the sealer control system is used to adjust at least one of the pressure, temperature or flow rate of carbon dioxide.

[0016] In the embodiment of the present disclosure, the sealing gas channel directly inputs the carbon dioxide discharged from the outlet of the cooling ring sleeve into the first annular gap from the inlet of the sealing gas channel without adjusting the flow rate and / or pressure.

[0017] In the embodiment of the present disclosure, the sealing gas control system includes: a storage tank connected to the outlet of the cooling ring sleeve, used to stabilize the pressure of the discharged carbon dioxide fluid; and a heat exchanger, used to adjust the temperature of the carbon dioxide according to the cooling requirements and then flow it into the first annular gap of the expander through the inlet of the sealing gas channel.

[0018] (III) Beneficial effects

[0019] It can be seen from the above technical solutions that the supercritical carbon dioxide expander based on the integrated cooling system disclosed in the present invention has at least one or part of the following beneficial effects:

[0020] (1) It can realize two purposes with one system, with simpler system structure and higher integration, which is conducive to improving the compactness of the unit;

[0021] (2) The series cooling of the casing and the main shaft is realized, which not only reduces the heating power consumption of the sealed air control system by utilizing the casing heating, but also satisfies the cooling of the casing and the shaft system at the same time, thus simplifying the cooling system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the cross-sectional structure of a supercritical carbon dioxide expander based on an integrated cooling system according to an embodiment of the present disclosure.

[0023] Figure 2 Schematic diagram of the structure of the sealing gas control system according to the embodiment of the present disclosure.

[0024] Figure 3 It is a schematic cross-sectional structure diagram of another supercritical carbon dioxide expander based on an integrated cooling system according to an embodiment of the present disclosure.

[0025] [Description of the main component symbols of the embodiment of the present disclosure in the accompanying drawings]

[0026] 101-Turbine;

[0027] 102-dry gas seal moving parts;

[0028] 103-spindle;

[0029] 201-volute;

[0030] 202- heat-insulating casing;

[0031] 203-sealed housing;

[0032] 204-dry gas seal static parts;

[0033] 205-cooling ring;

[0034] 301-first annular gap;

[0035] 302 - second annular gap;

[0036] 303 - third annular gap;

[0037] 401-Storage tank;

[0038] 402-Throttling and pressure reducing device;

[0039] 403-boosting pump;

[0040] 404-heat exchanger;

[0041] 405-flow regulating valve;

[0042] 406~408-stop valve;

[0043] A-seal gas channel inlet;

[0044] B1-cooling ring inlet;

[0045] B2-Cooling ring outlet. DETAILED DESCRIPTION

[0046] The present disclosure provides a supercritical carbon dioxide expander based on an integrated cooling system, specifically a structure of a turbine expander with supercritical carbon dioxide as the working fluid and a design of a cooling system. It adopts a casing and shaft system integrated cooling solution, and is integrated with a dry gas sealing system. There is no need to introduce additional sealing gas, which reduces redundant equipment and has a more compact structure. At the same time, the cooling gas flow, pressure, and temperature can be adjusted to meet the cooling requirements of the casing and the shaft system.

[0047] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0048] In an embodiment of the present disclosure, a supercritical carbon dioxide expander based on an integrated cooling system is provided. Figure 1 As shown, the supercritical carbon dioxide expander based on the integrated cooling system comprises:

[0049] The rotor part comprises:

[0050] Turbine 101;

[0051] A main shaft 103, one end of which is connected to the turbine 101; and

[0052] The dry gas seal moving component 102 is arranged on the other end of the main shaft 103 .

[0053] The casing part is arranged outside the rotor part, and includes:

[0054] The volute 201 is arranged at the periphery of the turbine;

[0055] A dry gas sealing static component 204 is arranged around the dry gas sealing dynamic component 102, and the dry gas sealing static component 204 is fixedly connected to the sealing housing 203;

[0056] The heat-insulating casing 202 is disposed between the volute 201 and the sealing casing 203, and forms a first annular gap 301 with the dry gas sealing moving part 102; a second annular gap 302 with the main shaft 103, and a third annular gap 303 with the turbine 101;

[0057] A cooling ring 205 is provided on the surface of the casing 203 for transmitting carbon dioxide and cooling the sealed casing 203. A cooling ring inlet B1 and a cooling ring outlet B2 are provided at opposite positions thereof. The cooling ring inlet B1 is used to introduce a certain flow of high-pressure and low-temperature supercritical carbon dioxide from the compressor side or other suitable positions of the system, flow heat exchange is performed inside the cooling ring 205, and the sealed casing 203 is cooled and then discharged from the cooling ring outlet B2; and

[0058] The sealed gas channel is used to input the carbon dioxide discharged from the cooling ring sleeve outlet B2 and adjusted by the sealer control system into the first annular gap 301 from the sealed gas channel inlet A, and then flow through the second annular gap 302 and then flow to the third annular gap 303, so as to realize simultaneous series cooling of the rotor part and the casing part.

[0059] The turbine comprises: a centripetal impeller or an axial flow impeller.

[0060] The turbine structure is a single-stage structure or a multi-stage structure.

[0061] The sealed casing 203 and the dry gas sealed static component 204 are connected together by fastening components such as bolts.

[0062] The seal is generally placed between the turbine and the bearing to prevent leaked gas from damaging the working environment of the bearing. Both the dry gas seal and the bearing have temperature limits, so cooling and heat insulation must be achieved between the turbine 101 and the dry gas seal 102. The specific cooling process is: a certain flow of high-pressure and low-temperature supercritical carbon dioxide fluid is introduced from the compressor side or other suitable positions of the system, and flows into the cooling ring 205 from the cooling ring inlet B1, thereby cooling the sealed casing 203 by convection heat exchange; then enters the cooling ring outlet B2 and flows out of the cooling ring 205, and then enters the external sealing gas control system to adjust its pressure, temperature, and flow, and then enters the sealing gas channel inlet A as the sealing gas of the dry gas seal, of which a small part of the sealing gas leaks out after being throttled by the friction pair, and most of the sealing gas will flow into the first annular gap 301, and then through the second annular gap 302, and after flowing to the third annular gap 303 on the turbine side, it will be mixed with the turbine inlet fluid, and discharged after doing work in the turbine, or it can be discharged through the drainage hole inside the insulation casing 202. The flow of sealing gas in the first annular gap 301 can cool and isolate the dry gas sealing moving parts 102 and the stationary parts 204 , the flow in the second annular gap 302 can directly perform convection cooling on the main shaft 103 , and the flow in the third annular gap 303 can cool and isolate the insulating casing 202 .

[0063] The sealing gas control system heats the sealing gas to a certain temperature to ensure that the sealing gas does not freeze after passing through the friction pair throttling.

[0064] In the embodiments of the present disclosure, Figure 2 As shown, the sealing gas control system comprises:

[0065] The storage tank 401 is connected to the cooling ring outlet B2 and is used to stabilize the pressure of the discharged carbon dioxide fluid;

[0066] The pressure regulating module includes three fluid pipelines arranged in parallel, wherein a throttling and pressure reducing device 402 and a booster pump 403 are respectively arranged on any two pipelines, and a stop valve (stop valve 406, stop valve 407, stop valve 408) is respectively arranged on each fluid pipeline;

[0067] The heat exchanger 404 is used to adjust the temperature of the carbon dioxide according to the cooling requirement and then flow into the first annular gap 301 of the expander through the sealed gas channel inlet A;

[0068] The flow regulating valve 405 is used to regulate the flow of the sealing gas.

[0069] The supercritical carbon dioxide after the cooling casing flows out from the cooling ring outlet B2 enters the sealing gas control system. After the pressure is stabilized by the storage tank 401, it can be pressurized by the booster pump 403 according to the flow requirements, or the throttling pressure reduction device 402 can be reduced, or the pressure does not need to be adjusted, and it can be directly circulated to the heat exchanger 404, and the temperature is adjusted according to the cooling requirements. Finally, the adjusted sealing gas flows into the sealed casing through the A channel. In addition to maintaining a sealed clean environment, the sealing gas also has a cooling function. The flow control valve 405 is used to regulate the flow of the sealing gas entering the casing; when the stop valve 406 is opened and the stop valve 407 and the stop valve 408 are closed, the sealing gas does not adjust the pressure; when the stop valve 406 and the stop valve 408 are closed, and the stop valve 407 is opened, the sealing gas is pressurized by the booster pump 403; when the stop valve 406 and the stop valve 407 are closed, and the stop valve 408 is opened, the sealing gas is reduced in pressure by the throttling pressure reduction device 402.

[0070] Figure 1 The middle seal gas is connected with the turbine inlet medium after passing through the annular gaps 301, 302, and 303. In addition, it can also be connected with the turbine outlet medium after work, such as Figure 3 As shown: the cooling gas passes through the annular gaps 301 and 302 and then radially flows into the working medium outlet annular cavity, and is discharged after being mixed with the outlet working medium.

[0071] Taking into account the cooling gas flow rate and temperature required for cooling, as well as the flow rate, pressure, temperature and other requirements required for the sealing gas, the parameters of the supercritical carbon dioxide at the cooling ring inlet B1 are optimized, so that it can flow directly into channel A without adjusting the flow rate and pressure, simplifying the sealing gas control system. Figure 2 The flow regulating valve 405, the stop valve 406, the stop valve 407, the stop valve 408, the throttling and pressure reducing device 402 and the boosting pump 403 can all be omitted.

[0072] The present disclosure introduces the heated supercritical carbon dioxide that has passed through the casing cooling ring 205 into the sealing system as sealing gas (wind), which can reduce the power consumption of heating. In addition, because the flow rate of the sealing gas does not affect the sealing effect of the dry gas seal, the flow rate of the sealing gas can be determined according to the cooling requirements of the casing and the spindle. The present disclosure integrates the cooling gas and the dry gas seal control system into one, which greatly simplifies the cooling system.

[0073] So far, the embodiments of the present disclosure have been described in detail in conjunction with the accompanying drawings. It should be noted that the implementation methods not shown or described in the drawings or the body of the specification are all forms known to ordinary technicians in the relevant technical field and are not described in detail. In addition, the above definitions of each element and method are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and ordinary technicians in the field can simply change or replace them.

[0074] According to the above description, those skilled in the art should have a clear understanding of the supercritical carbon dioxide expander based on the integrated cooling system of the present disclosure.

[0075] In summary, the present disclosure provides a supercritical carbon dioxide expander based on an integrated cooling system, wherein the cooling gas and dry gas sealing systems are integrated into one, realizing two purposes of one system, and the system structure is simpler and the integration is higher, which is conducive to improving the compactness of the unit. The series cooling of the casing and the main shaft is realized, which not only reduces the heating power consumption of the sealing air control system by utilizing the casing heating, but also can satisfy the cooling of the casing and the shaft system at the same time, simplifying the cooling system.

[0076] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only reference directions of the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present disclosure.

[0077] Moreover, the shapes and sizes of the components in the figures do not reflect the real size and proportion, but only illustrate the contents of the embodiments of the present disclosure. In addition, in the claims, any reference symbols between brackets shall not be constructed as limiting the claims.

[0078] Unless otherwise indicated, the numerical parameters in this specification and the appended claims are approximate values ​​and can vary according to the desired properties obtained through the content of the present disclosure. Specifically, all numbers used in the specification and claims to express the content of the composition, reaction conditions, etc., should be understood to be modified by the term "about" in all cases. In general, the meaning of the expression is to include a variation of ±10% in some embodiments, ±5% in some embodiments, ±1% in some embodiments, and ±0.5% in some embodiments by a specific number.

[0079] Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0080] The ordinal numbers used in the specification and claims, such as "first", "second", "third", etc., to modify the corresponding elements, do not themselves mean that the elements have any ordinal numbers, nor do they represent the order of one element and another element, or the order in the manufacturing method. The use of these ordinal numbers is only used to clearly distinguish a component with a certain name from another component with the same name.

[0081] In addition, unless the steps are specifically described or must occur in sequence, the order of the above steps is not limited to the above list, and can be changed or rearranged according to the required design. And the above embodiments can be mixed and matched with each other or with other embodiments based on design and reliability considerations, that is, the technical features in different embodiments can be freely combined to form more embodiments.

[0082] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and set in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and in addition they may be divided into multiple submodules or subunits or subcomponents. All features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this manner may be combined in any combination, except that at least some of such features and / or processes or units are mutually exclusive. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose. Furthermore, in a unit claim that lists several devices, several of these devices may be embodied by the same hardware item.

[0083] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various disclosed aspects, in the above description of the exemplary embodiments of the present disclosure, the various features of the present disclosure are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the following intention: the claimed disclosure requires more features than the features explicitly recited in each claim. More specifically, as reflected in the claims below, the disclosed aspects are less than all the features of the single embodiment disclosed above. Therefore, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, with each claim itself serving as a separate embodiment of the present disclosure.

[0084] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above description is only a specific embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A supercritical carbon dioxide expander based on an integrated cooling system, comprising: The rotor part comprises: A turbine, wherein the turbine is any one of a centripetal impeller and an axial flow impeller; a main shaft, one end of which is connected to the turbine; and A dry gas seal moving part is arranged on the other end of the main shaft; The casing part is arranged outside the rotor part, and includes: The volute is arranged outside the turbine; The dry gas seal static component is arranged around the dry gas seal dynamic component and is fixedly connected to the sealing housing; A heat-insulating casing, disposed between the volute and the sealing casing, forming a first annular gap with the dry gas seal moving part, a second annular gap with the main shaft, and a third annular gap with the turbine; and A cooling ring sleeve is arranged on the surface of the sealed casing, and is used to transmit carbon dioxide and cool the sealed casing. A cooling ring sleeve inlet and a cooling ring sleeve outlet are arranged at opposite positions. The cooling ring sleeve inlet is used to introduce a certain flow of high-pressure and low-temperature supercritical carbon dioxide from the compressor side, flow heat exchange is performed inside the cooling ring sleeve, and the carbon dioxide is discharged from the cooling ring sleeve outlet after cooling the sealed casing; and A sealing gas channel is used to input the carbon dioxide discharged from the cooling ring sleeve outlet and adjusted by the sealing gas control system into the first annular gap from the sealing gas channel inlet, and then flow through the second annular gap and then flow to the third annular gap, so as to realize simultaneous series cooling of the rotor part and the casing part; The sealing gas control system comprises: A storage tank connected to the outlet of the cooling ring sleeve and used for stabilizing the pressure of the discharged carbon dioxide fluid; A pressure regulating module, used for regulating the pressure of the carbon dioxide fluid, comprising three fluid pipelines arranged in parallel, wherein a throttling pressure reducing device and a booster pump are respectively arranged on any two pipelines, and a stop valve is respectively arranged on each fluid pipeline; A heat exchanger, used for adjusting the temperature of the carbon dioxide according to the cooling requirement and then flowing the carbon dioxide into the first annular gap of the expander through the inlet of the sealed gas channel; and Flow control valve, used to regulate the flow of sealing gas.

2. According to the supercritical carbon dioxide expander based on the integrated cooling system according to claim 1, the turbine structure is a single-stage structure or a multi-stage structure.

3. According to the supercritical carbon dioxide expander based on the integrated cooling system of claim 1, the sealed casing and the dry gas sealing static component are connected together by bolt fastening components.

4. According to the supercritical carbon dioxide expander based on the integrated cooling system of claim 1, the cooling ring sleeve is arranged on the surface of the sealed casing.

5. According to the supercritical carbon dioxide expander based on the integrated cooling system of claim 1, the sealing gas control system is used to adjust at least one of the pressure, temperature or flow of the carbon dioxide.

6. According to the supercritical carbon dioxide expander based on the integrated cooling system of claim 1, the sealing gas channel directly inputs the carbon dioxide discharged from the cooling ring sleeve outlet into the first annular gap from the sealing gas channel inlet without adjusting the flow rate and / or pressure.

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