A drain steam exhaust structure for an extraction back-pressure type air-cooled steam turbine unit

Abstract

The application provides a drainage steam exhaust structure for an extraction back-pressure type air-cooled steam turbine unit, and belongs to the technical field of steam drainage and exhaust of air-cooled steam turbine generator units, to solve the problems of low-pressure cylinder back-steam of steam during exhaust, easy freezing damage of equipment and system by steam entering the air-cooled island, and influence on safe operation of the steam turbine of the existing steam turbine exhaust structure. The application comprises a steam inlet pipeline assembly, a hot well, a steam exhaust device, a baffle plate, a flow guide plate and a return pipe; the steam exhaust device is provided with the baffle plate, the flow guide plate, a steam exhaust port and a low-pressure steam port, the low-pressure steam port is communicated with a low-pressure cylinder of the steam turbine, the baffle plate is located between the low-pressure steam port and the steam exhaust port on the steam exhaust device and separates the low-pressure steam port and the steam exhaust port, the steam inlet pipeline assembly is arranged through the baffle plate, and the flow guide plate is arranged opposite the steam outlet of the steam inlet pipeline assembly, so that the steam exhausted from the steam inlet pipeline assembly can be exhausted from the steam exhaust port on the steam exhaust device along the flow guide plate. The application is suitable for steam turbines.

Description

Technical Field

[0001] This invention relates to a condensate drainage and exhaust structure for a condensing-to-back-pressure air-cooled turbine generator unit, belonging to the field of condensate drainage and exhaust technology for air-cooled turbine generator units. Background Technology

[0002] On March 22, 2016, the National Development and Reform Commission, the National Energy Administration, the Ministry of Finance, the Ministry of Housing and Urban-Rural Development, and the Ministry of Environmental Protection jointly issued the "Administrative Measures for Combined Heat and Power (CHP)". The document states that the electricity generated by CHP units will be prioritized for purchase by power grid companies based on the principle of "heat-driven power generation," and that back-pressure turbine generator units will be given priority for heating-type combined cycle projects.

[0003] With the continuous emergence of 600MW and 1000MW heating units, and encouraged and promoted by the national energy conservation and emission reduction policies, 200MW air-cooled condensing units are facing the danger of being phased out. It is inevitable that they will be transformed into back-pressure units. After the transformation, the heating capacity will be improved, the waste heat loss will be zero, and the energy-saving and consumption-reducing effects will be outstanding.

[0004] After being converted from an air-cooled condensing turbine to a back-pressure turbine, it only operates during the winter heating season. The low-pressure rotor is replaced with a smooth shaft or a counterweight impeller is added. The atmospheric valve is removed from the upper part of the low-pressure cylinder, while the lower part remains unchanged and connected to the exhaust pipe. The original structure is as follows: Figure 1 As shown, before the improvement, the wet steam generated by the low-pressure cylinder, condensate expansion tank 3, low-pressure heater 21, high-pressure heater 17, heat network heater 18 and shaft heater 19 on the steam turbine 1 all enter the exhaust device 4, enter the air-cooled island to condense into water, and flow back to the hot well 5 through the return pipe 14. Finally, the water in the hot well 5 returns to the boiler for reuse.

[0005] Even after back-pressure modification, the unit still utilizes exhaust pipes and hot wells during operation. The exhaust pipes contain humid steam generated by various condensate drains. This humid steam, along with steam generated by the low-pressure cylinder, enters the exhaust system. Due to pressure imbalances in the condensate drain lines, some of this humid steam flows to the air-cooled island, while the rest returns to the low-pressure cylinder. The steam flowing to the air-cooled island is prone to freezing and damaging equipment and systems in winter, while the steam returning to the low-pressure cylinder keeps it in a high-temperature, humid state for extended periods. Both of these phenomena significantly impact the safe operation of the unit. Currently, the common solution is to add a condenser. However, both methods increase investment or operating costs, increase plant power consumption, complicate the system, and pose a risk of freezing. Summary of the Invention

[0006] In order to solve the problem that in the existing steam turbine exhaust structure, steam is prone to backflow into the low-pressure cylinder during exhaust, and the steam introduced into the air-cooled island is prone to freezing and damaging equipment and systems, and affecting the safe operation of the steam turbine, the present invention provides a multi-degree-of-freedom indexing anti-vibration connector.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0008] A condensate exhaust structure for a modified back-pressure air-cooled steam turbine unit includes an inlet pipe assembly, a hot well, an exhaust device, a plug plate, a guide plate, and a return pipe.

[0009] The exhaust device is equipped with a plug plate, a guide plate, an exhaust port, and a low-pressure steam port. The low-pressure steam port is connected to the low-pressure cylinder of the steam turbine. The plug plate is located between the low-pressure steam port and the exhaust port on the exhaust device, and isolates the low-pressure steam port and the exhaust port. The steam inlet pipeline assembly is installed through the plug plate. The guide plate is set relative to the steam outlet of the steam inlet pipeline assembly, so that the steam discharged from the steam inlet pipeline assembly can be discharged from the exhaust port on the exhaust device along the guide plate. The exhaust device is connected to the hot well through a return pipe.

[0010] Preferably, the guide vane is arc-shaped, with its concave surface facing the exhaust pipe plug.

[0011] Preferably, the steam inlet pipeline assembly includes a turbine drain pipe, a drain expansion tank, and a steam exhaust pipe. The turbine drain pipe is connected to the drain expansion tank. The steam outlet on the drain expansion tank is connected to the steam exhaust device through the steam exhaust pipe, and the steam exhaust pipe is set through a blockage plate. The steam exhaust pipe is set opposite to the guide plate. The drain expansion tank is connected to the hot well through a drain pipe.

[0012] Preferably, the steam inlet pipeline assembly further includes a high-pressure heater and a high-pressure heater exhaust pipe. The high-pressure heater is connected to the exhaust device through the high-pressure heater exhaust pipe, and the high-pressure heater exhaust pipe passes through the blockage plate.

[0013] Preferably, the steam inlet pipeline assembly further includes a low-pressure heater and a low-pressure heater exhaust pipe. The low-pressure heater is connected to the exhaust device through the low-pressure heater exhaust pipe, and the low-pressure heater exhaust pipe is installed through a blockage plate.

[0014] Preferably, the steam inlet pipeline assembly further includes a heat network heater and a heat network heater exhaust pipe. The heat network heater is connected to the exhaust device through the heat network heater exhaust pipe, and the heat network heater exhaust pipe passes through the blockage plate.

[0015] Preferably, the steam inlet pipeline assembly further includes a sealing water protection water pipe, which passes through the plug plate and is connected to the steam exhaust device.

[0016] Preferably, the steam inlet pipeline assembly further includes a shaft-mounted drain valve and a shaft-mounted drain pipe, wherein the shaft-mounted drain valve is connected to the hot well via the shaft-mounted drain pipe.

[0017] Preferably, the water inlet of the return pipe is located on the steam side of the guide plate.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. Shutting down the air-cooled island saves a significant amount of plant power. With the unit operating smoothly and the air-cooled island shut down, a substantial amount of plant power is saved, achieving energy conservation and emission reduction, and enhancing the power plant's profitability.

[0020] 2. No need to add a condenser, saving investment. The system is simple, requiring no additional condensing system or equipment, is not constrained by space, reduces investment and operating costs, and ensures stable unit operation.

[0021] 3. No backflow of steam into the low-pressure cylinder occurs. After the back pressure modification of the air-cooled unit, since the steam still flows to the exhaust device, a new blocking plate is added to the exhaust device. Each exhaust pipe passes through the blocking plate, which blocks the steam and prevents the steam from returning to the low-pressure cylinder chamber from the low-pressure steam port, thus maintaining the stable operation of the unit.

[0022] 4. No risk of freezing in the air-cooled tower. After the back pressure modification of the air-cooled unit, since steam still flows to the exhaust device and condensate still flows to the hot well, a baffle plate is added to the exhaust port of the exhaust device. This allows the steam discharged from the exhaust pipe and the wet steam generated by the condensate flowing to the hot well to be discharged into the atmosphere through the exhaust port, while preventing a large amount of steam from entering the air-cooled island. Only a small amount of wet steam that is not discharged condenses into water during its entry into the air-cooled island, and is finally discharged to the hot well through the return pipe. The air-cooled island has no risk of freezing, and the unit can maintain stable operation. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the invention before its improvement;

[0024] Figure 2 This is a schematic diagram of the improved version of the present invention;

[0025] Figure 3 This is a schematic diagram of the air deflector;

[0026] The reference numerals in the diagram are as follows: 1 is the steam turbine, 2 is the steam turbine drain pipe, 3 is the drain expansion tank, 4 is the exhaust device, 5 is the hot well, 6 is the high-pressure heater exhaust pipe, 7 is the low-pressure heater exhaust pipe, 8 is the heating network heater exhaust pipe, 9 is the exhaust pipe, 10 is the sealing water protection water pipe, 11 is the plug plate, 12 is the guide plate, 13 is the exhaust port, 14 is the return pipe, 15 is the drain pipe, 16 is the drain pipe, 17 is the high-pressure heater, 18 is the heating network heater, 19 is the steam seal heater, 20 is the shaft drain valve, and 21 is the low-pressure heater. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings: This embodiment is implemented under the premise of the technical solution of the present invention, and a detailed implementation method is given, but the protection scope of the present invention is not limited to the following embodiment.

[0028] Example 1: As Figure 2 As shown, this embodiment relates to a condensate-to-back-pressure air-cooled turbine unit with a steam condensation-to-back-pressure configuration, including a steam inlet pipeline assembly, a hot well 5 and a steam exhaust device 4, a plug plate 11, a guide plate 12 and a return pipe 14.

[0029] The exhaust device 4 is equipped with a blockage plate 11, a guide plate 12, an exhaust port 13, and a low-pressure steam port. The low-pressure steam port is connected to the low-pressure cylinder of the steam turbine, and the exhaust port of the low-pressure cylinder of the steam turbine is open to the atmosphere. The blockage plate 11 is located between the low-pressure steam port and the exhaust port 13 on the exhaust device 4 and isolates the low-pressure steam port and the exhaust port 13. The steam inlet pipeline assembly is installed through the blockage plate 11. The guide plate 12 is set relative to the steam outlet of the steam inlet pipeline assembly so that the steam discharged from the steam inlet pipeline assembly can be discharged from the exhaust port 13 on the exhaust device 4 along the guide plate 12. The exhaust device 4 is connected to the hot well 5 through the return pipe 14.

[0030] In this embodiment, the blocking plate 11 serves to isolate the exhaust port 13 and the low-pressure steam port to prevent steam from returning to the low-pressure cylinder. The blocking plate 11 can be installed at an angle or vertically to divide the exhaust device 4 into two chambers.

[0031] The guide plate 12 is arc-shaped, with its concave surface facing the exhaust pipe 9 and the blocking plate 11. This serves to guide the steam to the atmosphere and at the same time block some steam from entering the air-cooled island, thus preventing a large amount of steam from entering the air-cooled island and causing freezing.

[0032] like Figure 3 As shown, optionally, the shape of the guide plate 13 can be a curved plate, consisting of a vertical section and an inclined section, with the vertical end facing the exhaust port 13 and the inclined end facing the exhaust port of the intake pipe assembly.

[0033] The steam inlet pipeline assembly includes a steam turbine drain pipe 2, a drain expansion tank 3, and a steam exhaust pipe 9. The steam turbine drain pipe 2 is connected to the drain expansion tank 3. The steam outlet on the drain expansion tank 3 is connected to the steam exhaust device 4 through the steam exhaust pipe 9. The steam exhaust pipe 9 is installed through the blockage plate 11. The steam exhaust pipe 9 is installed opposite to the guide plate 12. The drain expansion tank 3 is connected to the hot well 5 through the drain pipe 16.

[0034] After the condensate from each stage of the steam turbine is depressurized and cooled by the condensate expansion tank 3, part of it is converted into steam with a relatively low pressure and temperature and discharged through the exhaust device 4. The other part of the unvaporized high-temperature water is discharged into the hot well 5 through the drain pipe 16 and returned to the boiler water circulation system for reuse.

[0035] This embodiment provides a condensate exhaust structure for a condensing-to-back-pressure air-cooled turbine unit. The steam inlet pipeline assembly also includes a high-pressure heater 17 and a high-pressure heater exhaust pipe 6. The high-pressure heater is connected to the exhaust device 4 through the high-pressure heater exhaust pipe 6, and the high-pressure heater exhaust pipe 6 passes through the blockage plate 11.

[0036] This embodiment provides a condensate exhaust structure for a condensing-to-back-pressure air-cooled turbine unit. The inlet pipeline assembly also includes a low-pressure heater 16 and a low-pressure heater exhaust pipe 7. The low-pressure heater 16 is connected to the exhaust device 4 through the low-pressure heater exhaust pipe 7, and the low-pressure heater exhaust pipe 7 passes through the blockage plate 11.

[0037] This embodiment provides a condensate drainage structure for a condensing-to-back-pressure air-cooled turbine unit. The inlet pipeline assembly also includes a heat network heater 18 and a heat network heater exhaust pipe 8. The heat network heater 18 is connected to the exhaust device 4 through the heat network heater exhaust pipe 8, and the heat network heater exhaust pipe 8 passes through the blockage plate 11.

[0038] This embodiment provides a condensate drainage structure for a modified back-pressure air-cooled steam turbine unit. The steam inlet pipeline assembly also includes a sealing water protection water pipe 10, which passes through a plug plate 11 and is connected to the exhaust device 4.

[0039] This embodiment provides a condensate drain structure for a condensing-to-back-pressure air-cooled turbine unit, which also includes a shaft-mounted drain valve and a shaft-mounted drain pipe 15. The shaft-mounted drain valve is connected to the hot well 5 through the shaft-mounted drain pipe 15.

[0040] The inlet of the return pipe 14 is located on the side of the guide plate 12 away from the steam, so that the water after the steam is condensed can be collected and flow into the hot well 5.

[0041] Example 2: The only difference between this example and Example 1 is that the exhaust port of the steam inlet pipe assembly is flush with the side of the plug plate 11 adjacent to the guide plate 12.

[0042] After the back pressure modification, the condensate from each stage of the turbine 1 is discharged into the condensate expansion tank 3 through the turbine condensate drain pipe 2. The condensate flash steam in the expansion tank 3 is discharged into the exhaust device 4 through the exhaust pipe 9, the high-pressure heater 17 through the high-pressure heater exhaust pipe 6, the low-pressure heater 21 through the low-pressure heater exhaust pipe 7, the heat network heater 18 through the heat network heater exhaust pipe 8, and the sealing water protection water device through the sealing water protection water pipe 10. Each pipe passes through the blocking plate 11 in the exhaust device 4. The blocking plate 11 isolates the exhaust port 13 from the low-pressure steam port, preventing steam from returning to the low-pressure cylinder of the turbine 1 from the low-pressure steam port on the exhaust device 4. The steam generated in the low-pressure cylinder of the turbine 1 is directly discharged into the atmosphere, avoiding backflow from the low-pressure cylinder and maintaining stable unit operation. Most of the steam that cannot return to the low-pressure cylinder passes through the guide plate 12 and is discharged into the atmosphere through the exhaust port 13. A small amount of steam that is not discharged into the atmosphere condenses into water through the air-cooled island, flows into the return pipe 14, and then flows to the hot well 5. The condensate drain expansion tank 3 is connected to the hot well 5 through the drain pipe 16, and the shaft-mounted condensate drain 20 is connected to the hot well 5 through the shaft-mounted condensate drain pipe 15. Finally, the condensate and drained water in the hot well 5 enter the regenerative system of the steam turbine 1.

[0043] The above description is merely a preferred embodiment of the present invention. These specific embodiments are different implementations based on the overall concept of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A condensate drain structure for a converted condensing-type air-cooled turbine unit, comprising an inlet pipe assembly, a hot well (5), a drain device (4), and a return pipe (14), characterized in that, The exhaust device (4) is equipped with a plug plate (11), a guide plate (12), an exhaust port (13) and a low-pressure steam port. The low-pressure steam port is connected to the low-pressure cylinder of the steam turbine. The plug plate (11) is located between the low-pressure steam port and the exhaust port (13) on the exhaust device (4) and isolates the low-pressure steam port and the exhaust port (13). The steam inlet pipeline assembly is set through the plug plate (11). The guide plate (12) is set relative to the steam outlet of the steam inlet pipeline assembly so that the steam discharged from the steam inlet pipeline assembly can be discharged from the exhaust port (13) on the exhaust device (4) along the guide plate (12). The exhaust device (4) is connected to the hot well (5) through the return pipe (14).

2. The condensate exhaust structure for a modified condensing-back-pressure air-cooled turbine unit according to claim 1, characterized in that, The guide plate (12) is arc-shaped, and the concave surface of the guide plate (12) faces the block plate (11).

3. The condensate exhaust structure for a condensing-to-back-pressure air-cooled turbine unit according to claim 1, characterized in that, The steam inlet pipeline assembly includes a steam turbine drain pipe (2), a drain expansion container (3), and a steam exhaust pipe (9). The steam turbine drain pipe (2) is connected to the drain expansion container (3). The steam outlet on the drain expansion container (3) is connected to the steam exhaust device (4) through the steam exhaust pipe (9). The steam exhaust pipe (9) is set through the blockage plate (11). The steam exhaust pipe (9) is set opposite to the guide plate (12). The drain expansion container (3) is connected to the hot well (5) through the drain pipe (16).

4. The condensate exhaust structure for a condensing-to-back-pressure air-cooled turbine unit according to claim 3, characterized in that, The steam inlet pipeline assembly also includes a high-pressure heater (17) and a high-pressure heater exhaust pipe (6). The high-pressure heater is connected to the exhaust device (4) through the high-pressure heater exhaust pipe (6), and the high-pressure heater exhaust pipe (6) is installed through the blockage plate (11).

5. A condensate exhaust structure for a condensing-to-back-pressure air-cooled turbine unit according to claim 4, characterized in that, The steam inlet pipeline assembly also includes a low-pressure heater (16) and a low-pressure heater exhaust pipe (7). The low-pressure heater (21) is connected to the exhaust device (4) through the low-pressure heater exhaust pipe (7), and the low-pressure heater exhaust pipe (7) is installed through the blockage plate (11).

6. A condensate exhaust structure for a converted condensing to back-pressure air-cooled steam turbine unit according to claim 5, characterized in that, The steam inlet pipeline assembly also includes a heat network heater (18) and a heat network heater exhaust pipe (8). The heat network heater is connected to the exhaust device (4) through the heat network heater exhaust pipe (8), and the heat network heater exhaust pipe (8) is installed through the blockage plate (11).

7. A condensate exhaust structure for a condensing-to-back-pressure air-cooled turbine unit according to claim 6, characterized in that, The steam inlet pipeline assembly also includes a sealing water protection water pipe (10), which passes through a plug plate (11) and is connected to the exhaust device (4).

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