Air turbine air seal system and method of operation thereof

Abstract

The present application belongs to the field of compressed air energy storage, and discloses an air turbine gas seal system and a working method thereof, aiming at solving the problems of large air leakage, high air leakage temperature and large air leakage energy loss of the existing air turbine structure. The present application is provided with a one-grade medium-pressure air inlet shaft seal loop, a two-grade low-pressure air inlet shaft seal loop, a three-grade medium-pressure exhaust shaft seal loop, a four-grade normal-pressure atmospheric shaft seal, a five-grade airtight shaft seal loop and a filtering pressure reducing valve on the air turbine gas seal system, so that the shaft seal leakage before high pressure and medium pressure is fully utilized, only a small amount of leakage is discharged into the atmosphere, the problem of affecting personnel safety caused by a large amount of high-temperature working medium leaking from the end gas seal is solved through the five-grade airtight shaft seal loop and the filtering pressure reducing valve, and the air consumption rate is reduced. The system provided by the present application has simple structure, less auxiliary equipment, less working medium leakage and high efficiency, and no high-enthalpy high-temperature working medium leakage.

Description

Technical Field

[0001] This invention relates to the field of compressed air energy storage, and in particular to an air turbine air seal system and its working method. Background Technology

[0002] To adapt to the new energy structure, the application of compressed air energy storage technology has been vigorously developed, and medium-temperature air turbines with multiple reheat functions have also been applied in many projects. Unlike traditional steam turbines, medium-temperature air turbines use air as the working fluid, which has a low temperature and multiple reheat cycles. Therefore, the requirements for their air sealing system are significantly different from those of steam turbines. The air working fluid used in air turbines allows for shaft seal leakage to the environment; the back pressure is atmospheric pressure, eliminating the need for low-pressure shaft seals to maintain a vacuum. Nevertheless, under actual operating conditions, air turbine air seals still need to minimize shaft seal leakage, reduce compressed air losses, and prevent high-temperature air from leaking from the shaft seals.

[0003] To reduce shaft seal leakage in multi-stage heated air turbines, it is urgent to design a new air turbine sealing system that can be used in medium-temperature three-stage heating, three-cylinder two-exhaust, high-power air turbines, reducing working fluid leakage and preventing leakage of working fluid at high temperatures. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an air turbine air seal system and its operating method, which solves the problems of limited number of gears and large air leakage in existing air turbine structures. Without multiple pressure distribution gears, high-temperature air may leak out when the blower is under low load, resulting in leakage of high-temperature working fluid and energy loss. Therefore, a high-power shaft seal fan is required.

[0005] To achieve the objective of this invention, the technical solution adopted is as follows: An air turbine sealing system includes a first-stage medium-pressure intake shaft seal circuit 1, a second-stage low-pressure intake shaft seal circuit 2, a third-stage medium-pressure exhaust shaft seal circuit 3, a fourth-stage atmospheric shaft seal 4, a fifth-stage airtight shaft seal circuit 5, and a filter pressure reducing valve 6.

[0006] Among them, a filter pressure reducing valve 6 is provided between the medium-pressure exhaust and the five-stage airtight shaft seal circuit 5.

[0007] The high-pressure front shaft seal first gear is connected to the medium-pressure intake pipe through the first gear medium-pressure intake shaft seal circuit 1; the high-pressure front shaft seal second gear and the medium-pressure front shaft seal first gear are connected to the low-pressure intake pipe through the second gear low-pressure intake shaft seal circuit 2.

[0008] Among them, the first gear of the high-pressure rear shaft seal, the third gear of the high-pressure front shaft seal, and the second gear of the medium-pressure front shaft seal are connected to the three-gear medium-pressure exhaust shaft seal circuit 3.

[0009] Among them, the fourth gear of the high-pressure front shaft seal, the second gear of the high-pressure rear shaft seal, the third gear of the medium-pressure front shaft seal, and the first gear of the medium-pressure rear shaft seal are connected to the fourth gear of the atmospheric shaft seal circuit 4, and are connected to the atmosphere.

[0010] Among them, the five-stage airtight shaft seal circuit 5 is connected to the medium-pressure exhaust pipe.

[0011] Among them, the five-stage airtight shaft seal circuit 5 connects the outermost stage of the high-pressure front shaft seal, the outermost stage of the high-pressure rear shaft seal, the outermost stage of the medium-pressure front shaft seal, the outermost stage of the medium-pressure rear shaft seal, and the low-pressure shaft seal circuit.

[0012] How air turbine air seal system works: (1) When the air turbine is running, the high-pressure front shaft seal has a high temperature and pressure. It enters the medium-pressure intake air with a similar temperature and enthalpy value through the first-stage medium-pressure intake shaft seal circuit. At the same time, the high-pressure front second-stage leakage and the medium-pressure front first-stage leakage enter the low-pressure intake air with a similar temperature and enthalpy value through the second-stage low-pressure intake shaft seal circuit. The high-temperature shaft seal leakage before high pressure and medium pressure is used to do work.

[0013] (2) The leakage of the first gear of the high pressure rear shaft seal, the leakage of the third gear of the high pressure front shaft seal, and the leakage of the second gear of the medium pressure front shaft seal enter the third gear medium pressure exhaust shaft seal circuit. The pressure of the third gear medium pressure exhaust shaft seal circuit is slightly greater than the low pressure intake pressure, which can prevent the leakage of the second gear of the high pressure front shaft seal and the leakage of the first gear of the medium pressure front shaft seal from continuing to flow to the outside. All the leakage of the high pressure front shaft seal and the leakage of the medium pressure front shaft seal are introduced into the low pressure intake for use. At the same time, the temperature of the shaft seal leakage before and after the high pressure and the subsequent medium pressure is the shaft seal gas after the work is done, and the temperature is close to the ambient temperature.

[0014] (3) The pressure of the three-stage medium-pressure exhaust shaft seal circuit is about 0.4MPa, which is greater than atmospheric pressure. The high-pressure front shaft seal leaks in the fourth stage, the high-pressure rear shaft seal leaks in the second stage, the medium-pressure front shaft seal leaks in the third stage, and the medium-pressure rear shaft seal leaks in the first stage. The leaked air enters the four-stage normal pressure atmospheric shaft seal circuit and is then discharged into the atmosphere. The temperature of the discharged atmosphere is close to normal temperature, the pressure difference is small, and the flow rate is greatly reduced.

[0015] (4) The air source of the five-stage airtight shaft seal circuit comes from the medium-pressure exhaust. The five-stage airtight shaft seal circuit is equipped with a filter pressure reducing valve to filter impurities in the medium-pressure exhaust. The five-stage airtight shaft seal circuit connects the outermost leak of the high-pressure front shaft seal, the outermost leak of the high-pressure rear shaft seal, the outermost leak of the medium-pressure front shaft seal, the outermost leak of the medium-pressure rear shaft seal, and the low-pressure shaft seal circuit. Then, the pressure of the five-stage airtight shaft seal circuit is set to 0.15MPa, which is greater than atmospheric pressure. All the leaks in the high-pressure shaft seal circuit and the medium-pressure shaft seal circuit are discharged into the atmosphere outside the factory through the four-stage normal pressure atmospheric shaft seal circuit. The leak from the end seal is a small amount of clean, filtered and depressurized medium-pressure exhaust at room temperature.

[0016] The above technical solution has the following beneficial effects: 1. The air turbine sealing system provided by the present invention is suitable for medium-temperature three-stage heating, three-cylinder two-exhaust, high-power air turbines. Through the setting of a first-stage medium-pressure intake shaft seal circuit, a second-stage low-pressure intake shaft seal circuit, and a third-stage medium-pressure exhaust shaft seal circuit, the shaft seal leakage before high pressure and before medium pressure is fully utilized.

[0017] 2. A small amount of leaking air at near-normal temperature and with a small pressure difference is discharged into the atmosphere through the four-stage atmospheric shaft seal circuit.

[0018] 3. By setting up a five-stage airtight shaft seal circuit and a filter pressure reducing valve, all air leaks from the high-pressure shaft seal circuit and the medium-pressure shaft seal circuit are discharged into the atmosphere outside the plant through the four-stage atmospheric shaft seal circuit. The leak from the end seal is a small amount of clean, filtered, and depressurized medium-pressure exhaust gas at room temperature. This solves the problems of turbine pressure reduction, high-pressure module blowing, high exhaust temperature rise, and large air leaks from the end seal when the pressure of the four-stage atmospheric shaft seal circuit rises due to excessive wear of the outer seal. It also solves the problem of halogen elements entering the flow through the end seal and leaking into the plant due to improper salt cavern energy storage treatment.

[0019] 4. The system provided by this invention has a simple structure, fewer auxiliary devices, less working fluid leakage, high efficiency, and prevents leakage of high-temperature working fluids with high enthalpy values. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the air turbine gas seal system of the present invention; In the diagram: 1 - First gear medium-pressure intake shaft seal circuit, 2 - Second gear low-pressure intake shaft seal circuit, 3 - Third gear medium-pressure exhaust shaft seal circuit, 4 - Fourth gear normal pressure atmospheric shaft seal, 5 - Fifth gear airtight shaft seal circuit, 6 - Filter pressure reducing valve. Detailed Implementation

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0022] Example 1 An air turbine sealing system includes a first-stage medium-pressure intake shaft seal circuit 1, a second-stage low-pressure intake shaft seal circuit 2, a third-stage medium-pressure exhaust shaft seal circuit 3, a fourth-stage atmospheric shaft seal 4, a fifth-stage airtight shaft seal circuit 5, and a filter pressure reducing valve 6.

[0023] Among them, a filter pressure reducing valve 6 is provided between the medium-pressure exhaust and the five-stage airtight shaft seal circuit 5.

[0024] The high-pressure front shaft seal first gear is connected to the medium-pressure intake pipe through the first gear medium-pressure intake shaft seal circuit 1; the high-pressure front shaft seal second gear and the medium-pressure front shaft seal first gear are connected to the low-pressure intake pipe through the second gear low-pressure intake shaft seal circuit 2.

[0025] Among them, the first gear of the high-pressure rear shaft seal, the third gear of the high-pressure front shaft seal, and the second gear of the medium-pressure front shaft seal are connected to the three-gear medium-pressure exhaust shaft seal circuit 3.

[0026] Among them, the fourth gear of the high-pressure front shaft seal, the second gear of the high-pressure rear shaft seal, the third gear of the medium-pressure front shaft seal, and the first gear of the medium-pressure rear shaft seal are connected to the fourth gear of the atmospheric shaft seal circuit 4, and are connected to the atmosphere.

[0027] Among them, the five-stage airtight shaft seal circuit 5 is connected to the medium-pressure exhaust pipe.

[0028] Among them, the five-stage airtight shaft seal circuit 5 connects the outermost stage of the high-pressure front shaft seal, the outermost stage of the high-pressure rear shaft seal, the outermost stage of the medium-pressure front shaft seal, the outermost stage of the medium-pressure rear shaft seal, and the low-pressure shaft seal circuit.

[0029] Example 2 How air turbine air seal system works: (1) When the air turbine is running, the high pressure front shaft seal has a high temperature and pressure. It enters the medium pressure intake air with a similar temperature and enthalpy value through the first medium pressure intake shaft seal circuit. At the same time, the high pressure front second gear leakage and the medium pressure front first gear leakage enter the low pressure intake air with a similar temperature and enthalpy value through the second low pressure intake shaft seal circuit. The high temperature shaft seal leakage before high pressure and medium pressure is used to do work. (2) The leakage of the first gear of the high pressure rear shaft seal, the leakage of the third gear of the high pressure front shaft seal, and the leakage of the second gear of the medium pressure front shaft seal enter the third gear medium pressure exhaust shaft seal circuit. The pressure of the third gear medium pressure exhaust shaft seal circuit is slightly greater than the low pressure intake pressure, which can prevent the leakage of the second gear of the high pressure front shaft seal and the leakage of the first gear of the medium pressure front shaft seal from continuing to flow to the outside. All the leakage of the high pressure front shaft seal and the leakage of the medium pressure front shaft seal are introduced into the low pressure intake for use. At the same time, the temperature of the shaft seal leakage before and after the high pressure and the subsequent medium pressure is the shaft seal gas after the work is done, and the temperature is close to the ambient temperature. (3) The pressure of the three-stage medium-pressure exhaust shaft seal circuit is about 0.4MPa, which is greater than atmospheric pressure. The high-pressure front shaft seal leaks in the fourth stage, the high-pressure rear shaft seal leaks in the second stage, the medium-pressure front shaft seal leaks in the third stage, and the medium-pressure rear shaft seal leaks in the first stage. The leaked air enters the four-stage normal pressure atmospheric shaft seal circuit and is then discharged into the atmosphere. The temperature of the discharged atmosphere is close to normal temperature, the pressure difference is small, and the flow rate is greatly reduced. (4) The air source of the five-stage airtight shaft seal circuit comes from the medium-pressure exhaust. The five-stage airtight shaft seal circuit is equipped with a filter pressure reducing valve to filter impurities in the medium-pressure exhaust. The five-stage airtight shaft seal circuit connects the outermost leak of the high-pressure front shaft seal, the outermost leak of the high-pressure rear shaft seal, the outermost leak of the medium-pressure front shaft seal, the outermost leak of the medium-pressure rear shaft seal, and the low-pressure shaft seal circuit. Then, the pressure of the five-stage airtight shaft seal circuit is set to 0.15MPa, which is greater than atmospheric pressure. All the leaks in the high-pressure shaft seal circuit and the medium-pressure shaft seal circuit are discharged into the atmosphere outside the factory through the four-stage normal pressure atmospheric shaft seal circuit. The leak from the end seal is a small amount of clean, filtered and depressurized medium-pressure exhaust at room temperature.

[0030] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An air turbine gas seal system, characterized in that: Includes a first-gear medium-pressure intake shaft seal circuit (1), a second-gear low-pressure intake shaft seal circuit (2), a third-gear medium-pressure exhaust shaft seal circuit (3), a fourth-gear normal pressure atmospheric shaft seal (4), a fifth-gear airtight shaft seal circuit (5), and a filter pressure reducing valve (6). A filter pressure reducing valve (6) is provided between the five-stage airtight shaft seal circuit (5) and the medium-pressure exhaust. The first gear of the high-pressure front shaft seal is connected to the medium-pressure intake pipe through the first gear medium-pressure intake shaft seal circuit (1); The second gear of the high-pressure front shaft seal and the first gear of the medium-pressure front shaft seal are connected to the low-pressure intake pipe through the two-gear low-pressure intake shaft seal circuit (2); The high-pressure rear shaft seal first gear, the high-pressure front shaft seal third gear and the medium-pressure front shaft seal second gear are connected to the three gears of the medium-pressure exhaust shaft seal return (3); The high-pressure front shaft seal fourth gear, the high-pressure rear shaft seal second gear, the medium-pressure front shaft seal third gear, and the medium-pressure rear shaft seal first gear are connected to the four gears of the normal pressure atmospheric shaft seal circuit (4), and are connected to the atmosphere; The five-stage airtight shaft seal circuit (5) is connected to the medium-pressure exhaust pipe; The five-stage airtight shaft seal circuit (5) connects the outermost stage of the high-pressure front shaft seal, the outermost stage of the high-pressure rear shaft seal, the outermost stage of the medium-pressure front shaft seal, the outermost stage of the medium-pressure rear shaft seal, and the low-pressure shaft seal circuit.

2. A method for operating the air turbine gas seal system as described in claim 1, characterized in that, Including the following steps: (1) When the air turbine is running, the first-stage leakage of the high-pressure front shaft seal enters the medium-pressure intake air with a similar temperature and enthalpy value through the first-stage medium-pressure intake shaft seal circuit. At the same time, the second-stage leakage of the high-pressure front and the first-stage leakage of the medium-pressure front enter the low-pressure intake air with a similar temperature and enthalpy value through the second-stage low-pressure intake shaft seal circuit. The high-temperature shaft seal leakage of the high-pressure front and the medium-pressure front are both used to do work. (2) The leakage of the first gear of the high pressure rear shaft seal, the leakage of the third gear of the high pressure front shaft seal, and the leakage of the second gear of the medium pressure front shaft seal enter the third gear medium pressure exhaust shaft seal circuit. The pressure of the third gear medium pressure exhaust shaft seal circuit is greater than the low pressure intake pressure, which can prevent the leakage of the second gear of the high pressure front shaft seal and the leakage of the first gear of the medium pressure front shaft seal from continuing to flow to the outside. All the leakage of the high pressure front shaft seal and the leakage of the medium pressure front shaft seal are introduced into the low pressure intake for use. At the same time, the temperature of the shaft seal leakage before and after the high pressure and the subsequent medium pressure is the shaft seal gas after the work is done, and the temperature is close to the ambient temperature. (3) The pressure of the three-stage medium-pressure exhaust shaft seal circuit is greater than atmospheric pressure. The high-pressure front shaft seal leaks in the fourth stage, the high-pressure rear shaft seal leaks in the second stage, the medium-pressure front shaft seal leaks in the third stage, and the medium-pressure rear shaft seal leaks in the first stage. The leaked air enters the four-stage normal pressure atmospheric shaft seal circuit and is then discharged into the atmosphere. The temperature of the discharged atmosphere is close to normal temperature, the pressure difference is small, and the flow rate is greatly reduced. (4) The air source of the five-stage airtight shaft seal circuit comes from the medium-pressure exhaust. The five-stage airtight shaft seal circuit is equipped with a filter pressure reducing valve to filter impurities in the medium-pressure exhaust. The five-stage airtight shaft seal circuit connects the outermost leak of the high-pressure front shaft seal, the outermost leak of the high-pressure rear shaft seal, the outermost leak of the medium-pressure front shaft seal, the outermost leak of the medium-pressure rear shaft seal, and the low-pressure shaft seal circuit. Then, the pressure of the five-stage airtight shaft seal circuit is set to be greater than atmospheric pressure. All the leaks in the high-pressure shaft seal circuit and the medium-pressure shaft seal circuit are discharged into the atmosphere outside the factory through the four-stage normal pressure atmospheric shaft seal circuit. The leak from the end seal is a small amount of clean, filtered and depressurized medium-pressure exhaust at room temperature.

3. The working method of the air turbine gas seal system according to claim 2, characterized in that: The pressure of the three-stage medium-pressure exhaust shaft seal circuit described in step (3) is approximately 0.4 MPa.

4. The working method of the air turbine gas seal system according to claim 2, characterized in that: The pressure of the five-stage airtight shaft seal circuit in step (4) is 0.15 MPa.

Images