Rotary machinery end seal leakage recovery device system and application thereof

Abstract

The invention provides a rotary machine end sealing leakage recovery device system and application thereof. The rotary machine end sealing leakage recovery device system comprises a labyrinth tooth type seal and a sealing machine room. The rotary machine comprises a turbine; the labyrinth tooth type seal is arranged on the connecting side of the turbine and the generator; the sealed machine room and the carbon dioxide gas storage device are connected in sequence; and a turbine and a generator are arranged in the sealed machine room. The leaked carbon dioxide is recovered and recycled in the system, full sealing of the carbon dioxide is achieved, and the manufacturing difficulty of key equipment is lowered.

Description

Technical Field

[0001] This invention relates to the field of rotating machinery end sealing technology, and more particularly to a rotating machinery end sealing leakage recovery device system and its application. Background Technology

[0002] Turbines (such as steam turbines, gas turbines, and compressors), as rotating devices that convert the thermal or kinetic energy of fluids into mechanical energy, typically contain high-temperature, high-pressure fluid media, such as steam or gas. Therefore, their safety, reliability, and economy are of paramount importance. Generally, a steam turbine consists of multiple stages of rotating and stationary blades, with relative rotational motion between the rotor and stator components. The high-temperature, high-pressure gas expands, driving the blades and shaft to move. The resulting mechanical energy is output outward through the rotation of the shaft, and then, through a magnetoelectric conversion mechanism, drives a generator to produce electrical energy.

[0003] The generator-motor connected to the blade shaft typically operates under normal temperature and pressure. The high-temperature, high-pressure gas inside the turbine should not escape through gaps in the rotating shaft, as this would affect the generator-motor's operation. The shaft sealing device is a core design challenge in high-temperature turbine design.

[0004] Normally, to ensure the turbine rotor and stator operate without vibration, friction, or scratches, a certain gap must be maintained between them. Under current design and manufacturing processes, this gap is approximately 0.8 mm. Due to this gap, secondary leakage of the working fluid is unavoidable. This not only reduces the amount of working fluid available for work but also affects the flow of the leaking fluid, significantly impacting the overall turbine efficiency. Losses due to this leakage can reach 22%-33% of the total turbine losses, greatly affecting turbine performance. Steam leakage in the cylinders also significantly impacts the safe and economical operation of the entire unit.

[0005] To reduce leakage losses and improve the overall efficiency of the steam turbine, a common practice is to add sealing devices at various clearance points. The effectiveness of the seal determines the safety, reliability, and economy of the mechanical equipment. Traditional rotary seals mainly include skeleton oil seals, labyrinth seals, and traditional mechanical seals. Traditional sealing technologies have the following technical disadvantages:

[0006] 1. Limitations in sealing performance: Labyrinth seals have inherent leakage and are extremely sensitive to gaps; mechanical seals require a lubrication and cooling system, are sensitive to impurities, and have high installation and maintenance requirements; brush seals have a short service life and have high requirements for shaft surfaces; floating ring seals require a stable fluid supply and have a complex structure.

[0007] 2. Insufficient adaptability of materials to working conditions: Sealing materials are prone to performance degradation, damage or corrosion under extreme working conditions such as high temperature, high pressure and strong corrosion, making it difficult to meet the needs of complex and ever-changing working environments.

[0008] 3. Design and Cost Issues: Sealing design involves multidisciplinary knowledge, is highly complex, and needs to adapt to the complex start-up, shutdown, and variable operating conditions of turbine machinery. High-performance sealing materials and complex sealing devices are expensive, increasing the manufacturing and maintenance costs of the equipment.

[0009] 4. With the development of steam turbine technology, the working load and operating parameters of steam turbines are constantly increasing, and the proportion of supercritical and ultra-supercritical units is increasing. The airflow excitation force of the corresponding sealing system is becoming more and more significant. The seal has become an important source of airflow excitation in the steam turbine. At the same time, achieving efficient and stable flow field inside the rotor seal is one of the guarantees for ensuring high performance and high safety of the turbomachinery.

[0010] 5. Insufficient development of technology for the recovery and utilization of gas sealing gases.

[0011] CN115726846A discloses a self-circulating dry sealing device for a supercritical carbon dioxide turbine generator, used for the dynamic sealing of a high-specific-power, compact supercritical carbon dioxide power system turbine generator set. It includes a labyrinth seal ring, a sealing cavity, and a dry sealing body. The labyrinth seal, as the primary sealing structure of the self-circulating dry sealing device, can significantly reduce the pressure of carbon dioxide discharged into the sealing cavity. The dry sealing body is used to suppress the leakage of carbon dioxide from the sealing cavity to the low-pressure side. The sealing cavity is connected to the low-pressure node of the main unit to form a self-circulating loop. Through the self-circulating loop, not only is the high-pressure CO2 retained in the sealing cavity recovered to the circulation system, but the negative feedback effect of the self-circulating loop also reduces the temperature and pressure of CO2 in the sealing cavity, thereby improving the protection of the dry sealing body from the high-temperature and high-pressure environment. This significantly reduces the technical requirements and construction costs of the dynamic sealing system for the supercritical fluid power system turbine generator.

[0012] CN111237468A discloses a combined hydrodynamic type rear isolation seal device for dry gas sealing of turbine machinery. The rear isolation seal device is disposed between the dry gas sealing assembly and the bearing housing, including a carbon ring sealing unit and a hydrodynamic type sealing unit. The carbon ring sealing unit is disposed between the dry gas sealing assembly and the hydrodynamic type sealing unit. The hydrodynamic type sealing unit includes a rotating assembly and a stationary assembly. The rotating assembly is sleeved on the outside of the main shaft and rotates at high speed with the main shaft. The stationary assembly is arranged around the main shaft and fixed to the housing. One end face of the rotating assembly and one end face of the stationary assembly are attached to form a sealing surface. The sealing surface is perpendicular to the axis of the main shaft. A hydrodynamic groove is provided on the end face of the rotating assembly.

[0013] CN104197020A discloses a radially dynamically adjustable contact seal device for a shaft end. The device is used to seal a rotating shaft and includes a sealing ring, a tension spring, and a mounting base. The tension spring is mounted on the sealing ring, which is nested within the mounting base and then assembled onto the rotating shaft to be sealed. Using a radially dynamically adjustable contact seal, the gap between the rotating shaft and the sealing ring is unaffected by temperature. Under the action of the circumferential tension spring, it automatically adjusts with changes in the diameter of the rotating shaft, maintaining contact with the shaft. Furthermore, even after prolonged operation, the sealing ring will not experience wear due to friction between the shaft and the sealing ring, thus preventing further leakage.

[0014] However, none of the aforementioned turbine sealing devices recovered and reused the leaked working fluid. Summary of the Invention

[0015] In view of the problems existing in the prior art, the present invention provides a rotary machinery end seal leakage recovery device system and its application. Through the synergistic cooperation of labyrinth tooth seal and sealing chamber, the sealing effect achieved by labyrinth tooth seal + dry gas seal is realized, and the leakage rate is less than 0.05% of the gas circulation flow rate. When applied to a direct-fired heating carbon dioxide circulation thermal system, carbon dioxide is recycled in the sealed circuit, which improves the system's economy and reliability and achieves the environmental protection goal of "zero carbon emissions".

[0016] To achieve this objective, the present invention adopts the following technical solution:

[0017] In a first aspect, the present invention provides a rotating machinery end seal leakage recovery device system, the rotating machinery end seal leakage recovery device system comprising a labyrinth tooth seal and a sealing chamber;

[0018] The rotating machinery includes a turbine; the labyrinth seal is disposed on the connection side between the turbine and the generator;

[0019] The sealed machine room and the carbon dioxide gas storage device are connected in sequence;

[0020] The pressure in the sealed machine room is 500-1000 Pa higher than the pressure of the carbon dioxide gas storage device;

[0021] The sealed machine room is equipped with a turbine and a generator.

[0022] The rotating machinery end seal leakage recovery device system of this invention features a labyrinth tooth seal on the connection side between the turbine and generator, and houses the turbine and generator within a sealed chamber, improving the sealing performance of the turbine shaft end. By sequentially connecting the sealed chamber and a carbon dioxide gas storage device, the leaked gas recovered from the labyrinth seal can be recycled, allowing for a reduction in the labyrinth tooth seal rating. This reduces the manufacturing difficulty of the labyrinth seal, improves its safety and lifespan, and eliminates the need for additional carbon capture equipment, thus enhancing the system's economic efficiency. The rotating machinery end seal leakage recovery device system reduces the sealing difficulty of the shaft seal, thereby reducing the manufacturing difficulty of the equipment.

[0023] The rotating machinery end seal leakage recovery device system described in this invention, through the coordinated cooperation of labyrinth tooth seal and sealing chamber, achieves a leakage rate of only one-thousandth compared to the current mainstream rotating machinery end seal technology where the internal working fluid of the high-pressure turbine leaks outward from the gap between the rotating shaft at a rate of 0.05%. The efficiency loss is only about 0.1%.

[0024] The pressure of the sealed machine room described in this invention is 500~1000Pa higher than the pressure of the carbon dioxide gas storage device, for example, it can be 500Pa, 610Pa, 730Pa, 850Pa, 980Pa or 1000Pa.

[0025] The sealing machine room and the carbon dioxide gas storage device of the present invention are connected by a valve on the connecting pipe; the carbon dioxide gas storage device includes a carbon dioxide gas bag, which is at atmospheric pressure, 101.325 kPa.

[0026] Preferably, the labyrinth tooth seal encloses the turbine's rotating mechanical rotor and gearbox.

[0027] Preferably, a combustion chamber is also provided inside the sealed machine room.

[0028] Preferably, the sealed machine room is also equipped with a temperature monitoring device and a pressure monitoring device.

[0029] The temperature monitoring device described in this invention monitors the temperature inside the sealed machine room to prevent abnormal temperature rise due to working fluid leakage. When the pressure monitoring device detects that the pressure in the sealed machine room is 500 Pa higher than the pressure of the carbon dioxide gas storage device, it can open the valve connecting the sealed machine room and the carbon dioxide gas storage device without the need for an additional pump set, thereby achieving the recovery of leaked working fluid and the complete sealing of the system. The pressure of the carbon dioxide gas storage device is approximately one atmosphere.

[0030] Preferably, the labyrinth tooth seal includes an interlaced labyrinth seal.

[0031] In a second aspect, the present invention also provides an application of the rotating machinery end seal leakage recovery device system as described in the first aspect, wherein the rotating machinery end seal leakage recovery device system is applied to a direct-fired heating type carbon dioxide cycle thermal system.

[0032] The rotary machinery end seal leakage recovery device system described in this invention is applied to a direct-fired heating carbon dioxide cycle thermal system to recover the carbon dioxide working fluid discharged from the labyrinth seal into a carbon dioxide gas storage device. It can then be applied to a carbon dioxide compression device, ensuring the recycling of the carbon dioxide working fluid and effectively promoting the economy and safety of the thermal system.

[0033] Preferably, the direct-fired heating type carbon dioxide cycle thermodynamic system includes a multi-stage intercooled compression unit for carbon dioxide, a liquid carbon dioxide storage device, a regenerative heating device, a combustion chamber, a turbine, and a carbon dioxide gas storage device, all connected in a cycle.

[0034] Preferably, the turbine is connected to the generator; the turbine and the generator are housed in a sealed machine room.

[0035] Preferably, the direct-fired heating type carbon dioxide cycle thermal system further includes an oxygen multi-stage intercooling and compression unit connected to the regenerative heating device; the liquid carbon dioxide storage device is connected to the oxygen multi-stage intercooling and compression unit via an oxygen recovery bypass pipeline.

[0036] Preferably, the direct-fired heating carbon dioxide cycle thermodynamic system further includes a heat storage medium circulation unit disposed between the carbon dioxide multi-stage intercooling compression unit and the regenerative heating device.

[0037] Preferably, the multi-stage intercooled carbon dioxide compression unit includes a carbon dioxide compression device and a carbon dioxide cooling device connected in sequence.

[0038] Preferably, a carbon dioxide capture pipeline is also provided between the multi-stage intercooled compression unit for carbon dioxide and the liquid carbon dioxide storage device.

[0039] Preferably, the oxygen multi-stage intercooled compression unit includes an oxygen compression device and an oxygen cooling device connected in sequence.

[0040] Preferably, the heat storage medium circulation unit includes a heat storage medium hot tank, a first transfer pump, a heat storage medium cold tank, and a second transfer pump that are connected in a circulating manner.

[0041] Preferably, the second delivery pump, the carbon dioxide cooling device, and the heat storage medium tank are connected in sequence.

[0042] Preferably, the first delivery pump, the regenerative heating device, and the heat storage medium cold tank are connected in sequence.

[0043] Compared with the prior art, the present invention has at least the following beneficial effects:

[0044] (1) The rotating machinery end seal leakage recovery device system provided by the present invention uses labyrinth tooth seal to wrap the turbine rotating machinery rotor and gearbox, and connects the sealed machine room with the external carbon dioxide gas storage device and carbon dioxide compression device, which reduces the manufacturing difficulty of shaft connection equipment, reduces the leakage of working fluid of rotating machinery, realizes zero carbon emissions of thermal system, and recovers and utilizes the leaked carbon dioxide working fluid to promote the recycling of resources.

[0045] (2) The pressure of the sealing chamber in the rotating machinery end seal leakage recovery device system provided by the present invention is 500~1000Pa higher than the pressure of the carbon dioxide gas storage device. The sealing chamber is easy to manufacture and does not require a pump set to recover to the carbon dioxide gas storage device. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the rotary machinery end seal leakage recovery device system applied to a direct-fired heating carbon dioxide cycle thermal system in Embodiment 1 of the present invention.

[0047] Figure 2 This is a schematic diagram of the staggered labyrinth seal in Embodiment 1 of the present invention.

[0048] Figure 3 This is a schematic diagram of the rotary machinery end seal leakage recovery device system applied to a direct-fired heating carbon dioxide cycle thermal system in Embodiment 2 of the present invention.

[0049] Figure 4 This is a schematic diagram of the rotary machinery end seal leakage recovery device system applied to a direct-fired heating carbon dioxide cycle thermal system in Embodiment 3 of the present invention.

[0050] In the diagram: 1- Labyrinth seal; 2- Sealed machine room; 3- Turbine; 4- Generator; 5- Carbon dioxide gas storage device; 6- Liquid carbon dioxide storage device; 7- Regenerative heating device; 8- Combustion chamber; 9- Oxygen recovery bypass pipeline; 10- First carbon dioxide compression device; 11- Second carbon dioxide compression device; 12- Third carbon dioxide compression device; 13- First carbon dioxide cooling device; 14- Second carbon dioxide cooling device; 15- Third carbon dioxide cooling device; 16- Carbon dioxide capture pipeline; 17- First oxygen compression device; 18- Second oxygen compression device; 19- Third oxygen compression device; 20- First oxygen cooling device; 21- Second oxygen cooling device; 22- Heat storage medium hot tank; 23- First transfer pump; 24- Heat storage medium cold tank; 25- Second transfer pump; 26- Electric motor; 27- Gas fuel compression device; 28- Condensation device; 29- Carbon dioxide pressurization device; 30- Second turbine; 31- Second labyrinth seal. Detailed Implementation

[0051] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0052] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0053] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0054] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0055] Those skilled in the art should understand that the present invention necessarily includes the necessary pipelines, conventional valves and general pump equipment for achieving process integrity, but the above content is not the main inventive point of the present invention. Those skilled in the art can add layouts based on process flow and equipment structure selection, and the present invention does not make any special requirements or specific limitations in this regard.

[0056] Example 1

[0057] This embodiment provides a rotating machinery end-seal leakage recovery device system. A schematic diagram of the rotating machinery end-seal leakage recovery device system applied to a direct-fired heating carbon dioxide cycle thermal system is shown below. Figure 1 As shown.

[0058] The rotating machinery end seal leakage recovery device system includes a labyrinth tooth seal 1 and a sealing chamber 2;

[0059] The rotating machinery includes a turbine 3; the labyrinth tooth seal 1 is disposed on the connection side between the turbine 3 and the generator 4;

[0060] The sealed machine room 2 and the carbon dioxide gas storage device 5 are connected in sequence; a valve is installed on the connecting pipe between the sealed machine room 2 and the carbon dioxide gas storage device 5.

[0061] The pressure in the sealed machine room 2 is 500 Pa higher than the pressure in the carbon dioxide gas storage device 5.

[0062] The sealed machine room 2 is equipped with a turbine 3 and a generator 4.

[0063] The labyrinth tooth seal 1 encloses the turbine rotating mechanical rotor and gearbox of the turbine 3.

[0064] The sealed machine room 2 is also equipped with a temperature monitoring device and a pressure monitoring device (not shown in the figure).

[0065] The labyrinth tooth seal 1 is an interlaced labyrinth seal, and its schematic diagram is shown below. Figure 2 As shown.

[0066] The gap between the sealing teeth of the staggered labyrinth seal is H. CL is the sealing length, a is the sealing height, Sg is the sealing groove width, b is the sealing tooth width, and S... in For sealing the inlet length, S out Ω represents the length of the sealing outlet and the pitch of the sealing teeth.

[0067] In this embodiment, the sealing tooth pitch Ω or sealing groove width Sg can be appropriately increased, or the sealing tooth tip gap can be increased, all of which can reduce the number of sealing teeth and reduce the manufacturing difficulty of the sealing equipment.

[0068] The direct-fired heating carbon dioxide circulating thermal system includes a circulating multi-stage intercooled compression unit for carbon dioxide, a liquid carbon dioxide storage device 6, a regenerative heating device 7, a combustion chamber 8, a turbine 3, and a carbon dioxide gas storage device 5. The combustion chamber 8 is connected to the gas fuel compression device 27.

[0069] The direct-fired heating carbon dioxide cycle thermal system also includes an oxygen multi-stage cold compression unit connected to the regenerative heating device 7; the liquid carbon dioxide storage device 6 is connected to the oxygen multi-stage cold compression unit via an oxygen recovery bypass pipe 9.

[0070] The direct-fired heating carbon dioxide circulating thermal system also includes a heat storage medium circulation unit located between the carbon dioxide multi-stage intercooling and compression unit and the regenerative heating device 7.

[0071] The multi-stage intercooled carbon dioxide compression unit includes a carbon dioxide compression device and a carbon dioxide cooling device connected in sequence.

[0072] In this embodiment, there are three sets of carbon dioxide compression devices, named the first carbon dioxide compression device 10, the second carbon dioxide compression device 11, and the third carbon dioxide compression device 12, respectively. The first carbon dioxide compression device 10 is connected to the electric motor 26.

[0073] In this embodiment, there are three sets of carbon dioxide cooling devices, which are named the first carbon dioxide cooling device 13, the second carbon dioxide cooling device 14, and the third carbon dioxide cooling device 15, respectively.

[0074] The first carbon dioxide compression device 10, the first carbon dioxide cooling device 13, the second carbon dioxide compression device 11, the second carbon dioxide cooling device 14, the third carbon dioxide compression device 12, and the third carbon dioxide cooling device 15 are connected in sequence.

[0075] A carbon dioxide capture pipeline 16 is also provided between the multi-stage intercooled compression unit for carbon dioxide and the liquid carbon dioxide storage device 6. A carbon dioxide pressurization device 29 is provided between the liquid carbon dioxide storage device 6 and the multi-stage intercooled compression unit for oxygen.

[0076] The oxygen multi-stage intercooled compression unit includes an oxygen compression device and an oxygen cooling device connected in sequence.

[0077] In this embodiment, there are three sets of oxygen compression devices, which are named the first oxygen compression device 17, the second oxygen compression device 18, and the third oxygen compression device 19, respectively.

[0078] In this embodiment, there are two sets of oxygen cooling devices, named the first oxygen cooling device 20 and the second oxygen cooling device 21, respectively.

[0079] The first oxygen compressor 17, the first oxygen cooler 20, the second oxygen compressor 18, the second oxygen cooler 21, and the third oxygen compressor 19 are connected in sequence.

[0080] The oxygen recovery bypass pipe 9 described in this embodiment is connected to the outlet of the second oxygen compression device 18 because the oxygen pressure at the top of the liquid carbon dioxide storage device 6 is 7 MPa, which is close to the outlet oxygen pressure of the second oxygen compression device 18.

[0081] The heat storage medium circulation unit includes a heat storage medium hot tank 22, a first delivery pump 23, a heat storage medium cold tank 24, and a second delivery pump 25, which are connected in a circulation manner.

[0082] The second delivery pump 25, the first carbon dioxide cooling device 13, and the heat storage medium tank 22 are connected in sequence;

[0083] The first delivery pump 23, the regenerative heating device 7, and the heat storage medium cold tank 24 are connected in sequence.

[0084] The direct-fired heating carbon dioxide cycle thermal system also includes a condensing device 28, and the regenerative heating device 7, the condensing device 28 and the first carbon dioxide compression device 10 are connected in sequence.

[0085] In this embodiment, the gas in the carbon dioxide gas storage device 5 sequentially enters the first carbon dioxide compression device 10, the first carbon dioxide cooling device 13, the second carbon dioxide compression device 11, the second carbon dioxide cooling device 14, the third carbon dioxide compression device 12, and the third carbon dioxide cooling device 15, where it is compressed and cooled into liquid carbon dioxide, which is then stored in the liquid carbon dioxide storage device 6. The heat of compression from the multi-stage interstage cooling and compression unit of carbon dioxide is stored in the heat storage medium circulation unit. The process includes: cold water in the heat storage medium cold tank 24 enters the first carbon dioxide cooling device 13 via the second transfer pump 25 to absorb the heat of compression, and then enters the heat storage medium hot tank 22 for storage; the first carbon dioxide compression device 10 is powered by an electric motor 26; the outlet of the third carbon dioxide cooling device 15 is also connected to the carbon dioxide capture pipeline 16 for carbon capture.

[0086] Afterwards, the liquid carbon dioxide in the liquid carbon dioxide storage device 6 is pressurized by the carbon dioxide pressurizing device 29, and the oxygen at the top of the liquid carbon dioxide storage device 6 enters the oxygen multi-stage cold compression unit through the oxygen recovery bypass pipe 9 to realize oxygen recovery; part of the carbon dioxide enters the regenerating heating device 7 for heating and then enters the combustion chamber 8 as a cooling medium to adjust the reaction temperature and prevent damage to the structure of the combustion chamber 8, and the other part enters the turbine 3 as a cooling medium to reduce the surface temperature of the blades.

[0087] At the multi-stage oxygen compression unit, external oxygen sequentially enters the first oxygen compression device 17, the first oxygen cooling device 20, the second oxygen compression device 18, the second oxygen cooling device 21, and the third oxygen compression device 19, becoming high-temperature, high-pressure oxygen at 20°C and 13.15 MPa. This oxygen then enters the regenerative heating device 7 for heating before entering the combustion chamber 8. Gaseous fuel is pressurized by the gaseous fuel compression device 27 and enters the combustion chamber 8 for combustion and heat release. The generated flue gas enters the turbine 3, expands, and performs work. The generator 4 converts the mechanical energy generated by the turbine 3 into electrical energy. The working fluid exiting the turbine 3 enters the regenerative heating device 7 to heat the high-pressure working fluid on the other side. Simultaneously, hot water from the heat storage medium tank 22 is sent to the regenerative heating device 7 via the first transfer pump 23 to supplement the heating of the regenerative heating device 7. After supplementary heating, cold water is generated and enters the heat storage medium cold tank 24 for recycling. The exhaust steam from the turbine 3 sequentially enters the regenerative heating device 7 and the condensation device 28, where water vapor is condensed into liquid water and separated, thus obtaining high-purity recycle carbon dioxide working fluid. The carbon dioxide leaked from turbine 3 enters the sealed machine room 2, and then enters the carbon dioxide gas storage device 5 for recycling.

[0088] This embodiment employs a labyrinth seal. Carbon dioxide gas flows from the high-pressure end to the low-pressure end under the influence of the pressure difference before and after sealing. As the carbon dioxide gas passes through the gaps, its velocity increases, and both pressure and temperature decrease; this process approximates an adiabatic throttling process. When the carbon dioxide gas enters the cavity between the sealing plates from the gaps, the sudden expansion of the flow area creates a strong vortex, causing the velocity to almost completely disappear, and all kinetic energy is converted into heat. This results in isobaric expansion within the cavity, where the pressure remains constant while the temperature rises, returning to the temperature before the sealing plate. This process repeats itself each time the carbon dioxide gas passes through a gap and cavity. The pressure decreases after each gap, and as the specific volume of the flowing carbon dioxide gas increases, its velocity through the gap continuously increases, resulting in a greater pressure drop as it passes downstream. This process repeats tooth by tooth until the entire seal is achieved, with decreasing pressure, increasing specific volume, and increasing carbon dioxide gas velocity. Finally, the pressure approaches the back pressure, while the temperature remains constant, thus achieving the sealing purpose.

[0089] In this embodiment, a non-contact sealed chamber is arranged at the shaft connection between the turbine and the generator. The sealed chamber is only connected to a carbon dioxide gas storage device and is equipped with a valve. The valve can be opened according to the pressure of the carbon dioxide gas storage device and the sealed chamber, so that the leaked carbon dioxide is recovered to the carbon dioxide gas storage device, and then the carbon dioxide in the carbon dioxide gas storage device is connected to the inlet of the first carbon dioxide compression device.

[0090] In this embodiment, a temperature monitoring device is installed in the sealed machine room to monitor the temperature inside the sealed machine room and prevent abnormal temperature rise in the sealed machine room due to leakage of the working fluid. A pressure monitoring device is installed in the sealed machine room. When the pressure monitored in the sealed machine room is 500 Pa higher than the pressure of the carbon dioxide gas storage device, the valve connecting the sealed machine room and the carbon dioxide gas storage device can be opened without the need for an additional pump set, so as to realize the recovery of the leaked working fluid and the complete sealing of the system. The pressure of the carbon dioxide gas storage device is about one atmosphere.

[0091] Taking thermal power units as an example, the function of the high-pressure cylinder shaft seal (end steam seal) is to prevent steam from leaking out along the rotor. The pressure difference borne by the high-pressure cylinder end steam seal is relatively large. In order to prevent collision between moving and stationary parts, a certain gap must be left. The existence of the gap will inevitably lead to leakage, and the leakage amount is generally 0.5% of the total steam volume. In the currently published high-speed high-pressure sCO2 dry gas seal performance test, when the seal operates under the typical design conditions of 4MPa and 40000r / min, the measured shaft seal leakage is about 2.4g / s. Based on the main flow rate of a typical 100kW-class sCO2 turbine, the leakage of 2.4g / s accounts for about 0.08%-0.24% of the total flow rate, which is an extremely low leakage level, demonstrating the high efficiency of dry gas seals in sCO2 turbines. On a 100kW-5MW test bench, the measured leakage at the shaft end using labyrinth or dry gas seals is mostly in the range of 0.5g / s-4g / s; when the unit's circulating flow rate is 1-4kg / s, the mass flow rate corresponding to this value is approximately 0.05%-0.4%.

[0092] The rotary machinery end seal leakage recovery device system provided in this embodiment allows carbon dioxide to leak into the sealing chamber, and the pressure in the sealing chamber is 500 Pa higher than that of the carbon dioxide gas storage device. In this case, the carbon dioxide gas seal does not need to be of a higher grade, and the leakage of shaft seals of current horizontal rotary machinery can be increased by an order of magnitude, from the current range of 0.5 g / s-4 g / s to 5 g / s-40 g / s, which reduces the manufacturing difficulty of labyrinth seal equipment.

[0093] Example 2

[0094] This embodiment provides a rotating machinery end-seal leakage recovery device system. A schematic diagram of the rotating machinery end-seal leakage recovery device system applied to a direct-fired heating carbon dioxide cycle thermal system is shown below. Figure 3 As shown.

[0095] The rotating machinery end seal leakage recovery device system is the same as in Example 1, except that the combustion chamber 8 is also located in the sealed machine room 2.

[0096] Except for the connection between the oxygen recovery bypass pipe 9 and the outlet of the third oxygen compression device 19, the direct-fired heating carbon dioxide cycle thermal system is the same as that in Example 1.

[0097] In this embodiment, the combustion chamber is also located in a sealed machine room, which further reduces the leakage of carbon dioxide working fluid and improves the "zero carbon emission" of the direct-fired heating carbon dioxide cycle thermal system, which has a significant effect on energy conservation and emission reduction.

[0098] In this embodiment, the oxygen recovery bypass pipeline is connected to the outlet of the third oxygen compressor because the oxygen pressure at the top of the liquid carbon dioxide storage device is 7 MPa, which is similar to the outlet oxygen pressure of the third oxygen compressor.

[0099] Example 3

[0100] This embodiment provides a rotating machinery end-seal leakage recovery device system. A schematic diagram of the rotating machinery end-seal leakage recovery device system applied to a direct-fired heating carbon dioxide cycle thermal system is shown below. Figure 4 As shown.

[0101] The rotating machinery end seal leakage recovery device system also includes a second turbine 30, which is disposed between the turbine 3 and the engine 4. A second labyrinth seal 31 is provided between the second turbine 30 and the generator 4. The turbine 3, the second turbine 30, and the engine 4 are all located outside the sealed machine room 2, and the rest is the same as in Embodiment 1.

[0102] Except for the connection between the oxygen recovery bypass pipe 9 and the outlet of the third oxygen compression device 19, the direct-fired heating carbon dioxide cycle thermal system is the same as that in Example 1.

[0103] This embodiment includes two turbines, both equipped with labyrinth tooth seals, and both are located in a sealed machine room, achieving the same technical effect as Embodiment 1, reducing carbon dioxide working fluid leakage.

[0104] In this embodiment, the oxygen recovery bypass pipeline is connected to the outlet of the third oxygen compressor because the oxygen pressure at the top of the liquid carbon dioxide storage device is 7 MPa, which is similar to the outlet oxygen pressure of the third oxygen compressor.

[0105] In summary, the labyrinth tooth seal design in the rotating machinery end seal leakage recovery device system provided by this invention reduces the manufacturing difficulty of rotating shaft components and recovers the carbon dioxide working fluid leaked from the labyrinth seal. Moreover, the connection between the sealing machine room and the carbon dioxide gas storage device enables the recovery and utilization of leaked carbon dioxide, reduces turbine shaft end leakage in direct-fired systems, improves economic efficiency, and has significant practical application value.

[0106] The present invention is described in detail through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0107] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A system for recovering leakage from the end seal of rotating machinery, characterized in that, The rotating machinery end seal leakage recovery device system includes a labyrinth tooth seal and a sealing chamber; The rotating machinery includes a turbine; the labyrinth seal is disposed on the connection side between the turbine and the generator; The sealed machine room and the carbon dioxide gas storage device are connected in sequence; The pressure in the sealed machine room is 500-1000 Pa higher than the pressure of the carbon dioxide gas storage device; The sealed machine room is equipped with a turbine and a generator.

2. The rotating machinery end seal leakage recovery device system according to claim 1, characterized in that, The labyrinthine tooth seal encloses the turbine's rotating mechanical rotor and gearbox.

3. The rotating machinery end seal leakage recovery device system according to claim 1, characterized in that, The sealed machine room is also equipped with a combustion chamber.

4. The rotating machinery end seal leakage recovery device system according to claim 1, characterized in that, The sealed machine room is also equipped with temperature monitoring devices and pressure monitoring devices.

5. The rotary machinery end seal leakage recovery device system according to claim 1, characterized in that, The labyrinth tooth seal includes an interlaced labyrinth seal.

6. The application of a rotary machinery end seal leakage recovery device system as described in any one of claims 1 to 5, characterized in that, The rotating machinery end seal leakage recovery device system is applied to a direct-fired heating type carbon dioxide cycle thermal system.

7. The application according to claim 6, characterized in that, The direct-fired heating carbon dioxide cycle thermodynamic system includes a multi-stage intercooled compression unit for carbon dioxide, a liquid carbon dioxide storage device, a regenerative heating device, a combustion chamber, a turbine, and a carbon dioxide gas storage device, all connected in a cycle. The turbine is connected to the generator; the turbine and generator are housed in a sealed engine room. The direct-fired heating carbon dioxide cycle thermodynamic system also includes an oxygen multi-stage cold compression unit connected to the regenerative heating device; the liquid carbon dioxide storage device is connected to the oxygen multi-stage cold compression unit via an oxygen recovery bypass pipeline. The direct-fired heating carbon dioxide cycle thermal system also includes a heat storage medium circulation unit located between the multi-stage intercooling and compression unit of carbon dioxide and the regenerative heating device.

8. The application according to claim 7, characterized in that, The multi-stage inter-stage carbon dioxide cold compression unit includes a carbon dioxide compression device and a carbon dioxide cooling device connected in sequence. A carbon dioxide capture pipeline is also provided between the multi-stage intercooled compression unit for carbon dioxide and the liquid carbon dioxide storage device.

9. The application according to claim 7, characterized in that, The oxygen multi-stage intercooled compression unit includes an oxygen compression device and an oxygen cooling device connected in sequence.

10. The application according to claim 7, characterized in that, The heat storage medium circulation unit includes a heat storage medium hot tank, a first delivery pump, a heat storage medium cold tank, and a second delivery pump that are connected in a circulation manner. The second delivery pump, the carbon dioxide cooling device, and the heat storage medium tank are connected in sequence; The first delivery pump, the regenerative heating device, and the heat storage medium cold tank are connected in sequence.

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