A steam turbine exhaust steam recovery system

Abstract

This invention relates to the field of steam turbine technology, specifically disclosing a steam turbine exhaust steam recovery system. The recovery system includes a recovery unit, multiple steam pipelines connected to the outside of the recovery unit, and two sets of heat exchange units arranged inside the recovery unit. The two sets of heat exchange units inside the recovery unit can operate independently, and each set of heat exchange units is connected to a corresponding cooling water inlet pipe and cooling water outlet pipe located outside the recovery unit. This invention effectively recovers bypass exhaust steam, condensate system exhaust steam, feedwater pump exhaust steam, and overflow steam from the back-compression turbine during turbine start-up and shutdown, avoiding waste of working fluid and damage to the ecological environment, and ensuring the safe and stable operation of large back-compression turbines. Secondly, addressing the actual technical requirements of power plants for half-side condenser operation, it enables four-process half-side operation, making unit maintenance and repair more convenient for power plants.

Description

Technical Field

[0001] This invention relates to the field of steam turbine technology, specifically a steam turbine exhaust steam recovery system. Background Technology

[0002] Conventional back-pressure turbine units directly release bypass steam, condensate system exhaust steam, and other waste steam into the atmosphere. This not only wastes a significant amount of working fluid but also damages the ecological environment, especially in large back-pressure units. This is because the large main steam flow rate in large back-pressure units exacerbates the problems of working fluid waste and environmental damage. Recovering this steam has become a crucial technical challenge for the development of larger back-pressure units. Furthermore, given current realities, many power plants require partial-side operation during unit maintenance or repair, for which there are currently no effective technical solutions.

[0003] In the prior art, CN203132382U discloses a condenser that can switch between dual-flow and four-flow modes, which focuses on switching between dual-flow and four-flow modes. Four-flow operation requires the use of external valves. CN209214394U discloses a condenser with four-flow modes, which adopts a single-inlet and single-outlet structure and cannot achieve half-side operation. CN107462082A discloses a condenser four-flow cooling water system and its usage method, which uses external pipeline valves to switch to achieve four-flow modes. None of these discloses any literature reports related to this invention. Summary of the Invention

[0004] The technical objective of this invention is to provide a turbine exhaust steam recovery system that can effectively solve the problem of working fluid waste in back-pressure turbine units and meet the requirements of half-side operation, taking into account the technical special characteristics and technical requirements of the operation of the aforementioned back-pressure turbine units and the shortcomings of the existing technology.

[0005] The technical objective of this invention is achieved through the following technical solution: a turbine exhaust steam recovery system, the recovery system comprising a recovery unit, multiple steam pipelines connected to the outside of the recovery unit, and two sets of heat exchange units arranged inside the recovery unit;

[0006] The two sets of heat exchange units inside the recovery unit can operate independently. Each set of heat exchange units is connected to a corresponding cooling water inlet pipe and cooling water outlet pipe located outside the recovery unit.

[0007] Furthermore, each heat exchange unit of the recoverer has a four-flow structure, having a front water chamber, a rear water chamber, a front turning water chamber, and multiple heat exchange tubes arranged between the front water chamber and the rear water chamber, and between the front turning water chamber and the rear water chamber.

[0008] The front water chamber has a cooling water inlet and a cooling water outlet;

[0009] The lower / upper part of the rear water chamber is used to redirect the incoming cooling water between the first and second flow processes;

[0010] The front turning water chamber is used to turn the incoming cooling water between the second and third processes;

[0011] The upper / lower part of the rear water chamber is used to divert the incoming cooling water between the third and fourth flow processes.

[0012] Furthermore, the recycler has a housing, a throat at the top of the housing, a front water chamber 1, a front turning water chamber 1, a front water chamber 2 and a front turning water chamber 2 arranged at one end of the housing, and a rear water chamber 1 and a rear water chamber 2 arranged at the other end of the housing.

[0013] The first front water chamber, the first rear water chamber, the first front turning water chamber, and the corresponding heat exchange tubes arranged in the shell form the first heat exchange unit.

[0014] The second front water chamber, the second rear water chamber, the second front turning water chamber, and the corresponding heat exchange tubes arranged in the shell form the second heat exchange unit.

[0015] The heat exchange tubes of the two heat exchange units form eight tube bundle regions inside the shell, and each set of four tube bundle regions forms a four-pass heat exchange unit.

[0016] Furthermore, the recycler has a throat located at the top of the housing, above the two sets of heat exchange units;

[0017] At the top of the throat, a low-pressure bypass interface is provided for connecting the low-pressure bypass exhaust pipe.

[0018] Furthermore, the recycler has a throat located at the top of the housing, above the two sets of heat exchange units;

[0019] At the top of the throat, there is a steam vent interface for connecting the steam vent pipe of the water supply pump.

[0020] Furthermore, the recycler has a throat located at the top of the housing, above the two sets of heat exchange units;

[0021] An overflow steam inlet is provided on the side of the throat for connecting the overflow steam pipe.

[0022] Furthermore, the recycler has a throat located at the top of the housing, above the two sets of heat exchange units;

[0023] A condensate venting port, serving as a condensate venting pipe, is provided on the side of the throat.

[0024] Furthermore, the recycler has a throat located at the top of the housing, above the two sets of heat exchange units;

[0025] A vacuum port is provided on the side of the throat.

[0026] Furthermore, the recycler also includes a hot well, which is integrated inside the shell and located at the bottom of the shell, for collecting and recycling condensate from the two sets of heat exchange units;

[0027] The side of the hot well is equipped with a liquid level measuring element for monitoring the operating water level inside the recovery unit.

[0028] Furthermore, the recycling system has two operating modes;

[0029] During normal operation, the recovery unit serves as a condenser for the feedwater pump turbine, used to recover the exhaust steam discharged from the feedwater pump, the exhaust steam from the turbine condensate system, and to receive the exhaust steam from the turbine bypass system when the back compressor bypass is in operation.

[0030] Under certain operating conditions, the recoverer serves as a condenser for the feedwater pump turbine, used to recover the exhaust steam discharged from the feedwater pump, the exhaust steam from the turbine condensate system, and, when the back compressor bypass is in operation, to receive the exhaust steam from the turbine bypass system and the overflow steam from the back compressor exhaust system.

[0031] The beneficial technical effects of this invention are as follows: Firstly, the above-mentioned technical measures can effectively recover bypass exhaust steam, condensate system exhaust steam, feedwater pump exhaust steam, and overflow steam from the back pressure turbine during start-up and shutdown, avoiding waste of working fluid and damage to the ecological environment, and ensuring the safe and stable operation of large back pressure turbines. Secondly, in response to the actual technical requirements of power plants for half-side operation of condensers, it can form a four-process half-side operation, making it more convenient for power plants to carry out unit overhaul or operation and maintenance. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the recycler of the present invention on one side.

[0033] Figure 2 for Figure 1 The left view.

[0034] Figure 3 for Figure 2 Top view.

[0035] Figure 4 for Figure 1 A schematic diagram of the operation process of the two heat exchange units.

[0036] The symbols in the diagram have the following meanings: 1—throat; 11—drainage and steam venting interface; 12—overflow steam interface; 13—feed water pump steam venting interface; 14—low-pressure bypass interface; 15—bypass desuperheater and pressure reducer; 16—vacuum interface; 2—shell; 3—first group of heat exchange units; 31—front water chamber one; 311—cooling water inlet one; 312—cooling water outlet one; 32—rear water chamber one; 33—front turning water chamber one; 4—second group of heat exchange units; 41—front water chamber two; 411—cooling water inlet two; 412—cooling water outlet two; 42—rear water chamber two; 43—front turning water chamber two. Detailed Implementation

[0037] This invention relates to the field of steam turbine technology, specifically a steam turbine exhaust steam recovery system, as described below with reference to the accompanying drawings. Figure 1 , Figure 2 , Figure 3 and Figure 4 The technical solution of the present invention will be clearly and thoroughly explained.

[0038] See Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the present invention is a waste steam recovery system for a back pressure unit, which includes a recovery unit, multiple steam pipelines connected to the outside of the recovery unit, and two sets of heat exchange units arranged inside the recovery unit.

[0039] Specifically, the recycler has a housing 2, a throat 1 arranged at the top of the housing 2, a front water chamber 31, a front turning water chamber 33, a front water chamber 41 and a front turning water chamber 43 arranged at one end of the housing 2, and a rear water chamber 32 and a rear water chamber 42 arranged at the other end of the housing 2.

[0040] The first heat exchange unit 3 consists of the first water chamber 31, the second water chamber 32, the first front turning water chamber 33, and the corresponding heat exchange tubes arranged within the shell 2. The second heat exchange unit 4 consists of the second water chamber 41, the second rear water chamber 42, the second front turning water chamber 43, and the corresponding heat exchange tubes arranged within the shell 2. The heat exchange tubes of the two heat exchange units form eight relatively independent tube bundle regions within the shell 2, with each group of four tube bundle regions forming a four-pass heat exchange unit. This allows the two heat exchange units within the recoverer to operate independently.

[0041] To ensure that the two sets of heat exchange units inside the heat exchanger can operate independently, each set of heat exchange units is connected to a corresponding cooling water inlet pipe and cooling water outlet pipe located outside the heat exchanger. Specifically, the first set of heat exchange units 3 has a cooling water inlet 311 located on the lower side and a cooling water outlet 312 located on the upper side in the front water chamber 31; the second set of heat exchange units 4 has a cooling water inlet 411 located on the lower side and a cooling water outlet 412 located on the upper side in the front water chamber 41.

[0042] With the above structure, each heat exchange unit of the heat recovery unit has a four-flow structure. The cooling water inlet of the front water chamber allows cooling water to enter and generate the first flow. The lower part of the rear water chamber turns the incoming cooling water left and right between the first and second flows. The front turning water chamber turns the incoming cooling water up and down between the second and third flows. The upper part of the rear water chamber turns the incoming cooling water left and right between the third and fourth flows. Finally, the cooling water is discharged through the cooling water outlet of the front water chamber.

[0043] The aforementioned recovery unit also includes a hot well, which is integrated inside the housing 2 and located at the bottom of the housing 2, for collecting and recovering condensate from the two sets of heat exchange units. A level measuring element—such as a level gauge—is installed on the side of the hot well to monitor the operating water level within the recovery unit.

[0044] The throat 1 of the aforementioned recovery unit is located at the top of the housing 2, above the two sets of heat exchange units, and serves as a connection to each exhaust pipe, thereby forming an interface for each exhaust pipe, including:

[0045] A low-pressure bypass interface 14 is provided for connecting the low-pressure bypass exhaust pipe, and the low-pressure bypass interface 14 is also connected to a bypass desuperheating and pressure reducing device 15.

[0046] A feedwater pump exhaust port 13 is provided for connecting the feedwater pump exhaust pipe;

[0047] An overflow steam inlet 12 is provided for connecting the overflow steam pipe;

[0048] It is equipped with a condensate venting port 11 for use as a condensate venting pipe;

[0049] It is equipped with a vacuum port 16, through which uncondensed gas is drawn away.

[0050] The exhaust steam recovery system of the back-pressure turbine unit with the above structure has the following two operating modes;

[0051] During normal operation, the recovery unit acts as a condenser for the feedwater pump turbine, used to recover the exhaust steam discharged from the feedwater pump, the exhaust steam from the turbine condensate system, and to receive the exhaust steam from the turbine bypass system when the back compressor bypass is in operation.

[0052] Under certain operating conditions, the recovery unit acts as a condenser for the feedwater pump turbine, used to recover the exhaust steam discharged from the feedwater pump, the exhaust steam from the turbine condensate system, and, when the back compressor bypass is in operation, to receive the exhaust steam from the turbine bypass system and the overflow steam from the back compressor exhaust system.

[0053] When the above-mentioned recycling system requires half-side operation, the first / second group of heat exchange units can be operated to cool the system.

[0054] The above specific technical solutions are only used to illustrate the present invention, and are not intended to limit it.

[0055] Although the present invention has been described in detail with reference to the specific technical solutions described above, those skilled in the art should understand that modifications can still be made to the specific technical solutions described above, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the present invention.

Claims

1. A turbine exhaust steam recovery system, characterized in that: The recovery system includes a recovery unit, multiple steam pipelines connected to the outside of the recovery unit, and two sets of heat exchange units arranged inside the recovery unit. The two sets of heat exchange units inside the recovery unit can operate independently. Each set of heat exchange units is connected to a corresponding cooling water inlet pipe and cooling water outlet pipe located outside the recovery unit. Each heat exchange unit of the recovery unit has a four-flow structure, including a front water chamber, a rear water chamber, a front turning water chamber, and multiple heat exchange tubes arranged between the front water chamber and the rear water chamber, and between the front turning water chamber and the rear water chamber. The front water chamber has a cooling water inlet and a cooling water outlet; The lower / upper part of the rear water chamber is used to redirect the incoming cooling water between the first and second flow processes; The front turning water chamber is used to turn the incoming cooling water between the second and third processes; The upper / lower part of the rear water chamber is used to redirect the incoming cooling water between the third and fourth flow processes; The recycler has a housing (2), a throat (1) at the top of the housing (2), a front water chamber 1 (31), a front turning water chamber 1 (33), a front water chamber 2 (41) and a front turning water chamber 2 (43) at one end of the housing (2), and a rear water chamber 1 (32) and a rear water chamber 2 (42) at the other end of the housing (2). The front water chamber (31), the rear water chamber (32), the front turning water chamber (33) and the corresponding heat exchange tubes arranged in the shell (2) form the first heat exchange unit (3). The front water chamber 2 (41), the rear water chamber 2 (42), the front turning water chamber 2 (43) and the corresponding heat exchange tubes arranged in the shell (2) form the second heat exchange unit (4). The heat exchange tubes of the two sets of heat exchange units form eight sets of tube bundle regions inside the shell (2), and each set of four sets of tube bundle regions forms a four-pass heat exchange unit. The recycling system has two operating modes; During normal operation, the recovery unit serves as a condenser for the feedwater pump turbine, used to recover the exhaust steam discharged from the feedwater pump, the exhaust steam from the turbine condensate system, and to receive the exhaust steam from the turbine bypass system when the back compressor bypass is in operation. Under certain operating conditions, the recoverer serves as a condenser for the feedwater pump turbine, used to recover the exhaust steam discharged from the feedwater pump, the exhaust steam from the turbine condensate system, and, when the back compressor bypass is in operation, to receive the exhaust steam from the turbine bypass system and the overflow steam from the back compressor exhaust system.

2. The turbine exhaust steam recovery system according to claim 1, characterized in that: The recycler has a throat (1) located at the top of the housing (2) and above the two sets of heat exchange units; At the top of the throat (1), a low-pressure bypass interface (14) is provided for connecting the low-pressure bypass exhaust pipe.

3. The turbine exhaust steam recovery system according to claim 1, characterized in that: The recycler has a throat (1) located at the top of the housing (2) and above the two sets of heat exchange units; At the top of the throat (1), there is a water supply pump exhaust port (13) for connecting the water supply pump exhaust pipe.

4. The turbine exhaust steam recovery system according to claim 1, characterized in that: The recycler has a throat (1) located at the top of the housing (2) and above the two sets of heat exchange units; An overflow steam port (12) for connecting an overflow steam pipe is provided on the side of the throat (1).

5. The turbine exhaust steam recovery system according to claim 1, characterized in that: The recycler has a throat (1) located at the top of the housing (2) and above the two sets of heat exchange units; A condensate venting port (11) for use as a condensate venting pipe is provided on the side of the throat (1).

6. The turbine exhaust steam recovery system according to claim 1, characterized in that: The recycler has a throat (1) located at the top of the housing (2) and above the two sets of heat exchange units; A vacuum port (16) is provided on the side of the throat (1).

7. The turbine exhaust steam recovery system according to claim 1, characterized in that: The recycler also includes a hot well, which is integrated inside the shell (2) and located at the bottom of the shell (2) for collecting and recycling condensate from the two sets of heat exchange units; The side of the hot well is equipped with a liquid level measuring element for monitoring the operating water level inside the recovery unit.

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