CN216691511U

CN216691511U - Compression expansion co-body machine for supercritical carbon dioxide Brayton system

Info

Publication number: CN216691511U
Application number: CN202121942142.1U
Authority: CN
Inventors: 王鹏亮; 金仕熙; 金鼎铭
Original assignee: Suzhou Eulerturbo Machinery Co ltd
Current assignee: Suzhou Eulerturbo Machinery Co ltd
Priority date: 2021-08-18
Filing date: 2021-08-18
Publication date: 2022-06-07
Anticipated expiration: 2031-08-18

Abstract

The utility model relates to a compression and expansion co-body machine for a supercritical carbon dioxide Brayton system, which comprises a compressor and an expander which are arranged in a cylinder body, wherein the compressor and the expander share a co-body impeller, the co-body impeller and the cylinder body form a compressor cavity and an expander cavity which are mutually independent and closed, the compressor cavity is provided with a compressor air inlet end and a compressor air outlet end, the expander cavity is provided with an expander air inlet end and an expander air outlet end, the co-body impeller is arranged on a main shaft of a supporting unit, the compressor is positioned between the expander and the supporting unit, one side of the compressor cavity and the expander cavity are sealed through a mechanical gap sealing element, and the other side of the compressor cavity and an external space are sealed through a mechanical dynamic sealing element. The utility model cancels the dynamic seal which has great design difficulty and prevents the high-temperature and high-pressure supercritical carbon dioxide gas of the expansion machine from leaking to the external space.

Description

Compression expansion co-body machine for supercritical carbon dioxide Brayton system

Technical Field

The utility model relates to a Brayton system, in particular to a compression-expansion co-body machine for a supercritical carbon dioxide Brayton system.

Background

The brayton cycle has no phase change in principle, and as an energy source, the thermal efficiency is far higher than about 40% of that of the current thermal power generation (rankine cycle), and theoretically can reach more than 75%. And the source of the required heat source is wide, and can be from petrochemical fuel, solar energy, biofuel, even waste heat and the like. The range of the heat source temperature is wide, and the heat source can be used generally only when the temperature reaches more than 500 ℃. The energy density is high, the installed power is the same, and the equipment is few and exquisite. The required auxiliary conditions are few, for example, the consumption of cooling water is far less than that of a thermal power plant, and the environment is protected. For the supercritical carbon dioxide brayton cycle, a great deal of research is put into both domestic and foreign experts and institutions.

In order to pursue the miniaturization and integration of the whole system structure, the arrangement of a compressor and an expander in the same cylinder is a feasible scheme, and the structure is that a compressor impeller and an expander impeller are installed on a cantilever on an extension shaft of a supporting system, and a sealing part is arranged between the impellers; the compressor and the expander are provided with through-flow static parts independently. How to shorten the extension section of the supporting system so as to improve the integral rigidity of the rotor has great significance for improving the rotor dynamics of the unit.

Meanwhile, the working temperature of the expander is above 500 ℃, the working pressure is above 20MPa, and at present, no mechanical dynamic seal meeting the conditions is available, so that even if a mechanical dynamic seal capable of bearing is researched in the future, the cost is high, and the method is one of the technical difficulties in researching the supercritical carbon dioxide Brayton cycle globally at present.

SUMMERY OF THE UTILITY MODEL

In order to overcome the defects, the utility model provides a compression and expansion co-body machine for a supercritical carbon dioxide Brayton system, wherein a compressor and an expander in the co-body machine share the same co-body impeller, so that a dynamic seal which is extremely difficult to design and prevents supercritical carbon dioxide gas with high temperature and high pressure of the expander from leaking to an external space is eliminated.

The technical scheme adopted by the utility model for solving the technical problem is as follows:

the utility model provides a supercritical carbon dioxide brayton system is with compression expansion intergral machine, is including installing compressor and the expander in the cylinder body, a intergral impeller of compressor and expander sharing, the intergral impeller forms mutually independent and confined compressor cavity and expander cavity with the cylinder body, it gives vent to anger the end to be equipped with compressor inlet end and compressor on the compressor cavity, it gives vent to anger the end to be equipped with expander inlet end and expander on the expander cavity, the intergral impeller is installed on the main shaft of supporting element, the compressor is located between expander and the supporting element, seal through mechanical type clearance sealing member between one side of compressor cavity and the expander cavity, move the sealing member through mechanical type between the opposite side of compressor cavity and the exterior space and seal.

Preferably, the common impeller comprises a wheel disc, compressor blades and expander blades, and the compressor blades and the expander blades are respectively and fixedly installed on two sides of the wheel disc.

Preferably, the integrated impeller further comprises a compressor wheel cover and an expander wheel cover, the compressor blades are fixedly installed between the wheel disc and the compressor wheel cover, and the expander blades are fixedly installed between the wheel disc and the expander wheel cover.

Preferably, the rim plate includes compressor wheel dish, expander wheel dish and well dish, compressor wheel dish and expander wheel dish are located respectively the both sides of well dish, the rim plate is integrated into one piece spare, or welds in at least one in compressor wheel dish and the expander wheel dish in the well dish, radial or the axial cover of mechanical type clearance seal is located the well dish.

Preferably, the wheel disc comprises a compressor wheel disc, an expander wheel disc and a spacer bush, the compressor wheel disc and the expander wheel disc are respectively installed on two sides of the spacer bush, and the mechanical clearance sealing element is radially or axially sleeved on the spacer bush.

Preferably, the mechanical gap sealing element is a comb tooth sealing element, the mechanical dynamic sealing element is a series dry gas sealing structure, and the supporting unit is a high-speed generator or a bearing seat.

Preferably, the expander inlet end is arranged along a radial direction of the cylinder block, the expander outlet end is arranged along an axial direction of the cylinder block, and the compressor inlet end and the compressor outlet end are both arranged along the radial direction of the cylinder block.

The utility model has the beneficial effects that: the compressor and the expander share the same impeller, and the compressor and the expander are arranged in the same cylinder body, so that on one hand, the requirement on the length of a main shaft of a unit is greatly reduced, the significance on improving the dynamic characteristic of a rotor is great, and the possibility of further improving the working rotating speed and increasing the installed power of a system is provided; on the other hand, for the expansion end, one side is an exhaust end of the expander, dynamic sealing is not needed, and the other side is in clearance type sealing through a mechanical clearance sealing element and the compression end, so that a small amount of high-temperature and high-pressure supercritical carbon dioxide leaks from a cavity of the expander to a cavity of the compressor, the work of the compressor is not influenced, and the dynamic sealing which is extremely difficult to design and prevents the high-temperature and high-pressure supercritical carbon dioxide gas of the expander from leaking to an external space is cancelled; for the external dynamic sealing of the expander and the compressor, only the mechanical dynamic sealing element on the compressor side is needed for sealing, and the carbon dioxide on the compressor side is low in temperature, so that the mechanical dynamic sealing element with mature technology is adopted for sealing, the problem of high-temperature and high-pressure dynamic sealing is converted into the problem of low-temperature sealing, a great problem of a supercritical carbon dioxide Brayton cycle system is solved, and the implementation and application of the system are realized; in the working state of the system, the impeller of the expansion machine directly drives the impeller of the compressor, so that the driving energy conversion of a compression end is avoided, and the system efficiency is improved.

Drawings

FIG. 1 is a schematic structural view of embodiment 1 of the present invention;

FIG. 2 is a schematic view of the flow direction of the media of FIG. 1;

FIG. 3 is a schematic view of the structure employing the axial gap seal in embodiment 1;

FIG. 4 is a schematic structural view of example 2 of the present invention;

FIG. 5 is a simplified diagram of the Brayton system of the present invention;

in the figure: 10-compressor, 11-compressor inlet, 12-compressor outlet, 20-expander, 21-expander inlet, 22-expander outlet, 30-co-body impeller, 31-compressor disk, 32-compressor blade, 33-compressor wheel cover, 34-expander disk, 35-expander blade, 36-expander wheel cover, 37-center disk, 38-spacer, 40-cylinder, 41-mechanical gap seal, 42-mechanical dynamic seal, 50-support unit, 51-main shaft, 61-heat source, 62-cooler, 63-gas control unit, 64-regulating valve, 65-preheater.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Spatially relative terms, such as "above … …," "above … …," "above … … surface," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

As shown in fig. 1 to 5, a compression-expansion co-machine for a supercritical carbon dioxide brayton system, comprises a compressor 10 and an expander 20 installed in a cylinder 40, the compressor 10 and the expander 20 share a common impeller 30, the common impeller 30 and the cylinder block 40 form a compressor chamber and an expander chamber which are independent and closed, the compressor cavity is provided with a compressor inlet end 11 and a compressor outlet end 12, the expander cavity is provided with an expander inlet end 21 and an expander outlet end 22, the common body impeller 30 is mounted on the main shaft 51 of the support unit 50, the compressor 10 is located between the expander 20 and the support unit 50, one side of the compressor chamber is sealed with the expander chamber by a mechanical clearance seal 41, and the other side of the compressor chamber is sealed with the external space by a mechanical dynamic seal 42.

One end of the main shaft 51 is supported by the supporting unit 50, and the other end is fixedly provided with the integrated impeller 30; as shown in fig. 5, arrows indicate gas flow directions, the brayton system includes a compressor 10, a heat source 61, an expander 20 and a cooler 62 which are connected in sequence and form a gas loop, and high-temperature gas from the expander 20 preheats the gas before the compressor 10 enters the heat source 61 through a preheater 65, a gas control unit 63 is arranged on the gas loop, a regulating valve 64 is arranged between the gas control unit and the gas loop, and the gas control unit 63 is used for supplementing or discharging the gas.

In the utility model, the compressor 10 and the expander 20 are arranged in the same cylinder body 40, and two independent closed spaces are formed in the cylinder body, so that working media of the compressor and the expander circulate through mutually independent circulation paths, a chamber of the compressor and a chamber of the expander are sealed by a common mechanical clearance sealing element, the sealing requirement is not high, and even if a small amount of high-temperature high-pressure supercritical carbon dioxide leaks into the chamber of the compressor from the chamber of the expander, the normal work of the compressor cannot be influenced; the compressor 10 and the expander 20 share the same integrated impeller 30, so that on one hand, the requirement on the length of a main shaft of a unit is greatly reduced, the significance on improving the dynamic characteristic of a rotor is great, and the possibility of further improving the working rotating speed and increasing the installed power of a system is provided; on the other hand, the dynamic seal which has great design difficulty and prevents the high-temperature and high-pressure supercritical carbon dioxide gas of the expansion machine from leaking to the external space is eliminated; for external dynamic sealing of the expander and the compressor, only the mechanical dynamic sealing element on the compressor side is needed for sealing, and the carbon dioxide on the compressor side is low in temperature, so that the mechanical dynamic sealing element with mature technology is adopted for sealing, for example, a series dry gas sealing structure is adopted, the problem of high-temperature and high-pressure dynamic sealing is changed into the problem of low-temperature sealing, a great problem of a supercritical carbon dioxide Brayton circulation system is solved, and the implementation and application of the system are realized.

The integrated impeller 30 comprises a wheel disc, compressor blades 32 and expander blades 35, wherein the compressor blades 32 and the expander blades 35 are fixedly installed on two sides of the wheel disc respectively. In this embodiment, the common body impeller is a semi-open impeller.

The integrated impeller 30 further comprises a compressor shroud 33 and an expander shroud 36, the compressor blades 32 are fixedly mounted between the wheel disc and the compressor shroud 33, and the expander blades 35 are fixedly mounted between the wheel disc and the expander shroud 36. In this embodiment, the common body impeller is a shrouded impeller.

Example 1: as shown in fig. 1 to 3, the wheel disc includes a compressor wheel disc 31, an expander wheel disc 34 and a middle disc 37, the compressor wheel disc 31 and the expander wheel disc 34 are respectively located at two sides of the middle disc 37, the wheel disc is an integrally formed piece, or at least one of the compressor wheel disc 31 and the expander wheel disc 34 is welded to the middle disc 37, and the mechanical gap sealing element 41 is radially or axially sleeved on the middle disc 37. The compressor wheel disc 31, the compressor blades 32 and the compressor wheel cover 33 form a compressor impeller, the compressor impeller is located in a compressor seal cavity, the expander wheel disc 34, the expander blades 35 and the expander wheel cover 36 form an expander impeller, the expander impeller is located in an expander seal cavity, the compressor impeller and the expander impeller are arranged in a back direction, as shown in figure 1, working media of the compressor and the expander circulate through mutually independent circulation channels, a radial gap seal (as shown in figure 2) is arranged on the outer diameter of a middle disc of the compressor impeller and the expander impeller, or an axial gap seal (as shown in figure 3) can be adjusted to be arranged on the middle disc structure, the expander impeller is located between an expander air outlet end and the compressor impeller, and for the expansion end, one side is the expander air outlet end, so that no dynamic seal is needed, and the other side is a compression end, the expansion machine is characterized in that a common mechanical clearance sealing element is used for sealing between the expansion machine cavity and the compressor cavity, the sealing requirement is not high, and the normal work of the compressor cannot be influenced even if a small amount of high-temperature high-pressure supercritical carbon dioxide leaks into the compressor cavity from the expansion machine cavity.

Example 2: as shown in fig. 4, the disk includes a compressor disk 31, an expander disk 34 and a spacer 38, the compressor disk 31 and the expander disk 34 are respectively installed on two sides of the spacer 38, and the mechanical gap seal 41 is radially or axially sleeved on the spacer 38. Compressor wheel disc 31 and expander wheel disc 34 are processed respectively and are formed, install two wheel discs respectively on spacer 38 and form an organic whole again, the spacer generally has thermal-insulated function, compressor wheel disc 31, compressor blade 32 and compressor wheel lid 33 form the compressor wheel, and this compressor wheel is located the sealed chamber of compressor, expander wheel disc 34, expander blade 35 and expander wheel lid 36 form the expander impeller, and this expander impeller is located the sealed chamber of expander, and compressor wheel and expander impeller are arranged dorsad, and the expander impeller is located the expander and gives vent to anger between end and the compressor wheel.

As shown in fig. 1, the mechanical gap seal 41 is a comb seal, the mechanical dynamic seal 42 is a series dry gas seal structure, and the support unit is a high-speed generator or a bearing seat. The tandem dry gas sealing structure is a container type structure formed by arranging medium side mechanical seal and atmosphere side dry gas seal in series front and back, the first-stage mechanical seal is a main seal, the second-stage dry gas seal is an auxiliary safety seal, the tandem dry gas sealing structure is a mature structure in the field and is not described in detail, and the tandem dry gas sealing structure is used for dynamic seal of a compressor and the outside and can meet the sealing requirement of the compressor; the broach is sealed also for the seal structure that uses always in compressor 10, sets up the broach of a mature technique between compressor cavity and expander cavity and seals, and as the dynamic seal of expander, can seal the most high-temperature gas in the expander cavity, even the high-temperature gas in a small amount of expander cavities leaks the admission that mixes into the compressor, gets into the compressor impeller, can not influence the normal operating of compressor yet, also can not bring harm for the environment simultaneously.

As shown in fig. 2, arrows indicate the flow direction of the medium, the expander inlet end 21 is arranged along the radial direction of the cylinder block 40, the expander outlet end 22 is arranged along the axial direction of the cylinder block 40, and the compressor inlet end 11 and the compressor outlet end 12 are both arranged along the radial direction of the cylinder block. Two independent closed spaces are formed in the cylinder body, so that working media of the compressor and the expander circulate through mutually independent circulation paths, the media in the compressor enter air through the air inlet end 11 of the compressor and exit air through the air outlet end of the compressor, and the media in the expander enter air through the air inlet end 21 of the expander and exit air through the air outlet end 22 of the expander; that is, the compressor 10 adopts the radial air intake and radial exhaust mode, and the expander adopts the radial air intake and axial exhaust mode, so for the impeller of the expander, one side is the exhaust end of the expander, no dynamic seal is needed, the other side realizes the clearance seal between the mechanical clearance seal 41 and the impeller of the compressor, a small amount of high-temperature and high-pressure supercritical carbon dioxide leaks to the chamber of the compressor from the chamber of the expander, the work of the compressor is not affected, and the dynamic seal for preventing the high-temperature and high-pressure supercritical carbon dioxide gas of the expander from leaking to the outside with great design difficulty is cancelled.

The implementation process of the utility model comprises the following steps: the method comprises the following steps:

the method comprises the following steps: machining of the conjoined impeller 30

The method comprises the following steps: directly processing an integral wheel disc, wherein one side of the wheel disc is a compressor wheel disc, the other side of the wheel disc is an expander wheel disc, and then processing blades and a wheel cover on the integral wheel disc to form a combined impeller 30;

the method 2 comprises the following steps: the compressor wheel disc 31 and the expander wheel disc 34 share one middle disc 37, the middle disc 37 is processed separately, or the middle disc comprises one of a compressor blade disc and an expander blade disc, then the compressor blade disc is welded on the middle disc, or the expander blade disc is welded on the middle disc, or the compressor blade disc and the expander blade disc are connected on the middle disc in a welding mode to form an integral wheel disc, and then blades and a wheel cover are processed on the integral wheel disc to form the integrated impeller 30;

the method 3 comprises the following steps: respectively processing a compressor wheel disc 31 and an expander wheel disc 34, installing the compressor wheel disc and the expander wheel disc on two sides of a spacer sleeve 38 to form an integral wheel disc, and processing blades and a wheel cover on the integral wheel disc to form a combined impeller 30;

in the combined impeller processed by the three processing methods, the compressor impeller and the expander impeller are arranged back to back along the axial direction;

step two: mounting the processed integrated impeller 30 on the extending end of the main shaft 51 of the supporting unit, and enabling the impeller side of the compressor to be close to the near end of the cantilever and the impeller side of the expander to be close to the far end of the cantilever;

step three: the common impeller 30 is installed in the common cylinder block 40, and the working medium flows through independent flow paths, and one side of the compressor chamber and the expander chamber are sealed by a mechanical gap seal 41, and the other side of the compressor chamber and the external space are sealed by a mechanical dynamic seal 42.

It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent should be subject to the appended claims.

Claims

1. A compression expansion co-body machine for a supercritical carbon dioxide Brayton system is characterized in that: comprises a compressor (10) and an expander (20) which are arranged in a cylinder body (40), the compressor (10) and the expander (20) share a common impeller (30), the common body impeller (30) and the cylinder body (40) form a compressor chamber and an expander chamber which are independent and closed, the compressor chamber is provided with a compressor inlet end (11) and a compressor outlet end (12), the expander cavity is provided with an expander inlet end (21) and an expander outlet end (22), the common body impeller (30) is mounted on a main shaft (51) of a support unit (50), the compressor (10) is located between the expander (20) and the support unit (50), one side of the compressor chamber and the expander chamber are sealed through a mechanical clearance sealing element (41), and the other side of the compressor chamber and the external space are sealed through a mechanical dynamic sealing element (42).

2. The compression-expansion co-machine for a supercritical carbon dioxide brayton system according to claim 1, characterized in that: the combined impeller (30) comprises a wheel disc, compressor blades (32) and expander blades (35), wherein the compressor blades (32) and the expander blades (35) are fixedly arranged on two sides of the wheel disc respectively.

3. The compression-expansion co-machine for a supercritical carbon dioxide brayton system according to claim 2, wherein: the integrated impeller (30) further comprises a compressor wheel cover (33) and an expander wheel cover (36), the compressor blades (32) are fixedly installed between the wheel disc and the compressor wheel cover (33), and the expander blades (35) are fixedly installed between the wheel disc and the expander wheel cover (36).

4. The compression-expansion co-machine for a supercritical carbon dioxide brayton system according to claim 2, characterized in that: the rim plate includes compressor rim plate (31), expander rim plate (34) and well dish (37), compressor rim plate (31) and expander rim plate (34) are located respectively the both sides of well dish (37), the rim plate is integrated into one piece, perhaps welds in at least one in compressor rim plate (31) and the expander rim plate (34) and coils (37), mechanical type clearance seal (41) are radially or axial to be located well dish (37).

5. The compression-expansion co-machine for a supercritical carbon dioxide brayton system according to claim 2, characterized in that: the wheel disc comprises a compressor wheel disc (31), an expander wheel disc (34) and a spacer bush (38), the compressor wheel disc (31) and the expander wheel disc (34) are respectively installed on two sides of the spacer bush (38), and the mechanical gap sealing piece (41) is radially or axially sleeved on the spacer bush (38).

6. The compression-expansion co-machine for a supercritical carbon dioxide brayton system according to claim 1, characterized in that: the mechanical gap sealing element (41) is a comb tooth sealing element, the mechanical dynamic sealing element (42) is a series dry gas sealing structure, and the supporting unit (50) is a high-speed generator or a bearing seat.

7. The compression-expansion co-machine for a supercritical carbon dioxide brayton system according to claim 1, wherein: the expander inlet end (21) is arranged along the radial direction of the cylinder body (40), the expander outlet end (22) is arranged along the axial direction of the cylinder body (40), and the compressor inlet end (11) and the compressor outlet end (12) are both arranged along the radial direction of the cylinder body.