Shaft seal steam sealing system of saturated backpressure steam turbine

Abstract

The utility model discloses a saturated backpressure steam turbine shaft seal steam sealing system which comprises a backpressure machine, a front steam seal section and a rear steam seal section, a steam inlet pipeline and a steam exhaust pipeline are connected to the backpressure machine, a steam turbine rotor is installed in the backpressure machine, the steam outlet end of the front steam seal section is communicated with the steam exhaust pipeline through a first pipeline, and the steam outlet end of the rear steam seal section is communicated with the steam exhaust pipeline through a second pipeline. The steam outlet end of the second front steam seal section is communicated with the steam outlet end of the first rear steam seal section through a second pipeline, the second pipeline is connected with a steam inlet in the upper portion of the surface cooler through a second branch pipe, the surface cooler is provided with a first cooling water pipeline and a first atmosphere discharging pipe, and the bottom of the surface cooler is connected with the water collecting tank through a first drainage pipe. Furthermore, the front steam seal section can be designed into five sections, and the rear steam seal section can be designed into four sections, so that the use of a shaft seal cooler and compressed air is increased. Based on the technical scheme, the solar water heater has the advantages of being reasonable in design, low in cost, high in energy efficiency, safe, environmentally friendly and wide in application range.

Description

Technical Field

[0001] The utility model belongs to the technical field of steam turbines, and in particular relates to a shaft seal steam sealing system for a saturated back pressure steam turbine. Background Art

[0002] A steam turbine with an exhaust pressure greater than atmospheric pressure is called a back-pressure steam turbine. During the operation of a back-pressure steam turbine, since the exhaust pressure is higher than the atmospheric pressure, steam and water leakage often occurs at the turbine shaft end, especially in saturated back-pressure units, where the steam and water leakage is very obvious. During the operation of a saturated unit, water will gradually be generated, and part of the water will be brought into the shaft seal by steam, and then carried out of the front and rear steam seals when rotating with the main shaft, and finally encounter the atmosphere to form water mist. Utility Model Content

[0003] In order to solve the above technical defects, the purpose of the utility model is to provide a saturated back pressure steam turbine shaft seal steam system to solve the above back pressure machine shaft seal steam leakage problem, especially the saturated back pressure machine shaft seal steam leakage problem.

[0004] The technical solution of the utility model is:

[0005] A saturated back-pressure steam turbine shaft seal steam system comprises a back-pressure machine, a front steam seal section and a rear steam seal section, the back-pressure machine is connected to a steam inlet pipeline and an exhaust pipeline, a steam turbine rotor is installed in the back-pressure machine, the front steam seal section comprises a front steam seal section 1 and a front steam seal section 2 arranged from the inside to the outside, the rear steam seal section comprises a rear steam seal section 1, a steam outlet end of the front steam seal section 1 is connected to the exhaust pipeline through a first pipeline, a steam outlet end of the front steam seal section 2 is connected to the steam outlet end of the rear steam seal section 1 through a second pipeline, and the second pipeline is connected to the steam inlet at the top of a surface cooler through a second branch pipe, a first row of atmospheric pipes is provided on the top of the surface cooler, a first cooling water pipeline is arranged in the surface cooler, a water outlet end of the first cooling water pipeline is connected to a deaerator through an external water outlet pipeline, and the bottom of the surface cooler is connected to a water collecting tank through a first drain pipe.

[0006] Preferably, the front steam seal section also includes a front steam seal section 3 arranged on the outside of the front steam seal section 2, and the rear steam seal section also includes a rear steam seal section 2 arranged on the outside of the rear steam seal section 1, the steam outlet end of the front steam seal section 3 is connected with the steam outlet end of the rear steam seal section 2 through a third pipeline, and the third pipeline is connected to the steam inlet on the upper part of the shaft seal cooler through a third branch pipe, a second row of atmospheric pipes is provided on the top of the shaft seal cooler, a second cooling water pipeline is arranged in the shaft seal cooler, the water outlet end of the second cooling water pipeline is connected to the water inlet end of the first cooling water pipeline through an intermediate cooling water pipeline, the water inlet end of the second cooling water pipeline is connected to the softened water system through an external water inlet pipeline, and the bottom of the shaft seal cooler is connected to the water collecting tank through a second drain pipe.

[0007] Preferably, the front steam seal section also includes a front steam seal section 4 arranged on the outside of the front steam seal section 3, and the rear steam seal section also includes a rear steam seal section 3 arranged on the outside of the rear steam seal section 2, the steam outlet end of the front steam seal section 4 is connected to the steam outlet end of the rear steam seal section 3 through a fourth pipeline, and the fourth pipeline is connected to a compressed air source through a compressed air pipe.

[0008] Preferably, the front steam seal section also includes a front steam seal section 5 arranged outside the front steam seal section 4, and the rear steam seal section also includes a rear steam seal section 4 arranged outside the rear steam seal section 3, which plays a role in isolating the atmosphere.

[0009] Preferably, a regulating valve is installed on the air inlet end of the compressed air pipe to reduce the pressure of the compressed air at the air inlet end.

[0010] Preferably, the second branch pipe and the first row of atmospheric pipes are both equipped with switch valves to achieve flow regulation of the gas in the pipes.

[0011] Preferably, the third branch pipe and the second row of atmospheric pipes are both equipped with switch valves to achieve flow regulation of the gas in the pipes.

[0012] Preferably, an exhaust fan is installed on the second row of atmospheric pipes to improve exhaust efficiency.

[0013] Preferably, the water inlet pipeline, the intermediate cooling water pipeline and the water outlet pipeline are all equipped with switch valves to achieve flow control of softened water in the pipes.

[0014] Preferably, a U-shaped water seal is provided at the water inlet end of the second drain pipe to isolate the water from the atmosphere.

[0015] The utility model has the following beneficial effects:

[0016] 1. The utility model effectively reduces the steam leakage and water leakage of the shaft seal of the saturated back pressure steam turbine through the design of the number of steam seals of the front steam seal section and the rear steam seal section, as well as the use of surface coolers, shaft seal coolers and compressed air, and also recycles the heat energy and water source of the steam leakage;

[0017] 2. The saturated back-pressure steam turbine shaft seal steam sealing system provided can also be modified and used on high back-pressure back-pressure units and units with steam leakage during on-site operation;

[0018] 3. The utility model has reasonable design, low cost, high energy efficiency, safety, environmental protection and wide application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a structural schematic diagram of a saturated back-pressure steam turbine shaft seal steam sealing system of the utility model;

[0020] In the figure: 1-back compressor, 2-front steam seal section 1, 3-front steam seal section 2, 4-front steam seal section 3, 5-front steam seal section 4, 6-front steam seal section 5, 7-rear steam seal section 1, 8-rear steam seal section 2, 9-rear steam seal section 3, 10-rear steam seal section 4, 11-surface cooler, 12-shaft seal cooler, 13-exhaust fan, 14-U-type water seal, 15-compressed air source, 16-regulating valve. DETAILED DESCRIPTION

[0021] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0022] like Figure 1 As shown, the utility model provides a saturated back-pressure steam turbine shaft seal steam sealing system, comprising a back-pressure machine 1, a front steam seal section and a rear steam seal section, the back-pressure machine 1 is connected to a steam inlet pipeline and an exhaust pipeline, a steam turbine rotor is installed in the back-pressure machine 1, the front steam seal comprises five sections, the rear steam seal comprises four sections, and the rear leakage steam of the front steam seal section 1 2 is connected to the exhaust steam, the rear leakage steam of the front steam seal section 2 3 and the rear steam seal section 1 7 is connected to the surface cooler 11, the rear leakage steam of the front steam seal section 3 4 and the rear steam seal section 2 8 is connected to the shaft seal cooler 12 and the exhaust fan 13, the compressed air is connected to the rear sides of the front steam seal section 4 5 and the rear steam seal section 3 9 through a regulating valve, and the front steam seal section 5 6 and the rear steam seal section 4 10 are used to isolate the atmosphere.

[0023] Specifically, the front steam seal section includes front steam seal section 1 2, front steam seal section 2 3, front steam seal section 3 4, front steam seal section 4 5, and front steam seal section 5 6, which are arranged from the inside to the outside, and the rear steam seal section includes rear steam seal section 1 7, rear steam seal section 2 8, rear steam seal section 3 9, and rear steam seal section 4 10, which are arranged from the inside to the outside. The steam outlet end of the front steam seal section 1 2 is connected to the exhaust pipeline through the first pipeline, so as to discharge the higher pressure steam on the left side of the back pressure machine 1 close to the steam inlet pipeline through the exhaust pipeline.

[0024] The steam outlet end of the second section of the front steam seal 3 is connected to the steam outlet end of the first section of the rear steam seal 7 through a second pipeline, and a second branch pipe is provided on the second pipeline, and the second branch pipe is connected to the steam inlet at the top of the surface cooler 11. The top of the surface cooler 11 is provided with a first row of atmospheric pipes, and a first cooling water pipeline is arranged inside the surface cooler 11. The water outlet end of the first cooling water pipeline is connected to the deaerator through an external water outlet pipeline, and a first drain pipe is provided at the bottom of the surface cooler 11, and the first drain pipe is connected to the water collecting tank. For the second section of the front steam seal 3 and the first section of the rear steam seal 7, since the non-condensable gas in the surface cooler 11 is connected to the atmosphere through the first row of atmospheric pipes, the exhaust side pressure of the surface cooler 11 is close to the atmospheric pressure, which will increase the pressure difference between the second section of the front steam seal 3 and the first section of the rear steam seal 7, and increase the steam leakage. When designing, it is necessary to increase the number of steam seals of the second section of the front steam seal 3 and the first section of the rear steam seal 7, so as to reduce the steam leakage of the second section of the front steam seal 3 and the first section of the rear steam seal 7.

[0025] The steam outlet end of the front steam seal section 3 4 is connected to the steam outlet end of the rear steam seal section 2 8 through a third pipeline, and a third branch pipe is provided on the third pipeline, and the third branch pipe is connected to the steam inlet on the upper part of the shaft seal cooler 12, and a second row of atmospheric pipes is provided on the top of the shaft seal cooler 12, and a second cooling water pipeline is arranged in the shaft seal cooler 12, and the water outlet end of the second cooling water pipeline is connected to the water inlet end of the first cooling water pipeline through an intermediate cooling water pipeline, and the water inlet end of the second cooling water pipeline is connected to the softened water system through an external water inlet pipeline, and a second drain pipe is provided at the bottom of the shaft seal cooler 12, and the second drain pipe is connected to the water collecting tank. For the front steam seal section 3 4 and the rear steam seal section 2 8, since the front steam seal section 2 3 and the rear steam seal section 1 7 are connected to the surface cooler 11 through pipelines, and the exhaust side pressure of the surface cooler 11 is close to the atmospheric pressure, the front and rear pressure difference of the front steam seal section 2 3 and the rear steam seal section 1 7 is increased, and the front and rear pressure difference of the front shaft seal section 3 and the rear shaft seal section 2 is also reduced, thereby reducing the steam leakage to the shaft seal cooler 12. In addition, the condensation effect of the shaft seal cooler 12 further reduces the steam leakage of the subsequent axial sections of the turbine, and the recycling of the leaked steam is also realized.

[0026] The steam outlet end of the front steam seal section 4 5 is connected to the steam outlet end of the rear steam seal section 3 9 through the fourth pipeline, and a compressed air pipe is arranged on the fourth pipeline, and the compressed air pipe is connected to the compressed air source 15, and a regulating valve 16 is installed on the air inlet end of the compressed air pipe to reduce the pressure of the compressed air at the air inlet end. For the front steam seal section 4 5 and the rear steam seal section 3 9, the compressed air from the compressed air source 15 is reduced in pressure by the regulating valve 16 to produce compressed air of ~0.03mpa(g), and after entering the front steam seal section 4 5 and the rear steam seal section 3 9 respectively, its main function is to prevent isolation from the atmosphere, and to prevent the front steam seal section 3 4 and the rear steam seal section 2 8 from leaking steam, and also reduce water leakage when the rotor rotates.

[0027] The second branch pipe and the first row of large air pipes are both equipped with switch valves to achieve flow regulation of the gas in the pipes.

[0028] The third branch pipe and the second row of large air pipes are both equipped with switch valves to achieve flow regulation of the gas in the pipes.

[0029] An exhaust fan 13 is installed on the second row of atmospheric pipes to improve exhaust efficiency.

[0030] The water inlet pipeline, the intermediate cooling water pipeline and the water outlet pipeline are all equipped with switch valves to realize the flow control of the softened water in the pipeline.

[0031] A U-shaped water seal 14 of a certain height is provided at the water inlet end of the second drain pipe to isolate the water from the atmosphere.

[0032] In specific implementation, the utility model provides a saturated back-pressure steam turbine shaft seal steam sealing system, in which the shaft seal cooler 12 and the surface cooler 11 both use softened water. The softened water is first heated by the shaft seal cooler 12 and then heated by the surface cooler 11, and then enters the deaerator. At the same time, the drain water in the shaft seal cooler 12 and the drain water in the surface cooler 11 are collected in the water collecting tank, thereby achieving comprehensive energy utilization and improving system efficiency.

[0033] The present invention may also have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A saturated back pressure steam turbine shaft seal steam sealing system, characterized in that: It includes a back pressure machine, a front steam seal section and a rear steam seal section. The back pressure machine is connected to a steam inlet pipeline and a steam exhaust pipeline. A steam turbine rotor is installed in the back pressure machine. The front steam seal section includes a front steam seal section one and a front steam seal section two arranged from the inside to the outside. The rear steam seal section includes a rear steam seal section one. The steam outlet end of the front steam seal section one is connected with the exhaust pipeline through a first pipeline, the steam outlet end of the front steam seal section two is connected with the steam outlet end of the rear steam seal section one through a second pipeline, and the second pipeline is connected with the steam inlet at the top of the surface cooler through a second branch pipe. The top of the surface cooler is provided with a first row of atmospheric pipes, a first cooling water pipeline is arranged in the surface cooler, the water outlet end of the first cooling water pipeline is connected to a deaerator through an external water outlet pipeline, and the bottom of the surface cooler is connected to a water collecting tank through a first drain pipe.

2. A saturated back pressure steam turbine shaft seal steam sealing system according to claim 1, characterized in that: The front steam seal section also includes a front steam seal section 3 arranged on the outside of the front steam seal section 2, and the rear steam seal section also includes a rear steam seal section 2 arranged on the outside of the rear steam seal section 1. The steam outlet end of the front steam seal section 3 is connected with the steam outlet end of the rear steam seal section 2 through a third pipeline, and the third pipeline is connected to the steam inlet on the upper part of the shaft seal cooler through a third branch pipe. A second row of atmospheric pipes is provided on the top of the shaft seal cooler, and a second cooling water pipeline is arranged in the shaft seal cooler. The water outlet end of the second cooling water pipeline is connected to the water inlet end of the first cooling water pipeline through an intermediate cooling water pipeline, and the water inlet end of the second cooling water pipeline is connected to the softened water system through an external water inlet pipeline, and the bottom of the shaft seal cooler is connected to the water collecting tank through a second drain pipe.

3. A saturated back pressure steam turbine shaft seal steam sealing system according to claim 2, characterized in that: The front steam seal section also includes a front steam seal section 4 arranged on the outside of the front steam seal section 3, and the rear steam seal section also includes a rear steam seal section 3 arranged on the outside of the rear steam seal section 2. The steam outlet end of the front steam seal section 4 is connected to the steam outlet end of the rear steam seal section 3 through a fourth pipeline, and the fourth pipeline is connected to a compressed air source through a compressed air pipe.

4. A saturated back pressure steam turbine shaft seal steam sealing system according to claim 3, characterized in that: The front steam seal section also includes a front steam seal section 5 arranged outside the front steam seal section 4, and the rear steam seal section also includes a rear steam seal section 4 arranged outside the rear steam seal section 3.

5. A saturated back pressure steam turbine shaft seal steam sealing system according to claim 4, characterized in that: A regulating valve is installed on the air inlet end of the compressed air pipe.

6. A saturated back pressure steam turbine shaft seal steam sealing system according to claim 5, characterized in that: The second branch pipe and the first row of atmospheric pipes are both equipped with switch valves.

7. A saturated back pressure steam turbine shaft seal steam sealing system according to claim 6, characterized in that: The third branch pipe and the second row of atmospheric pipes are both equipped with switch valves.

8. A saturated back pressure steam turbine shaft seal steam sealing system according to claim 7, characterized in that: An exhaust fan is installed on the second row of atmospheric pipes.

9. A saturated back pressure steam turbine shaft seal steam sealing system according to claim 8, characterized in that: The water inlet pipeline, the intermediate cooling water pipeline and the water outlet pipeline are all equipped with switch valves.

10. A saturated back pressure steam turbine shaft seal steam sealing system according to claim 9, characterized in that: A U-shaped water seal is provided at the water inlet end of the second drain pipe.

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