Steam-driven induced draft fan waste heat utilization system and thermal generator set

Abstract

The utility model relates to a steam-driven induced draft fan waste heat utilization system and a thermal generator set, and the steam-driven induced draft fan waste heat utilization system comprises an induced draft fan steam turbine used for driving an induced draft fan; a first inlet end of the steam turbine condenser is communicated with a steam exhaust outlet of the induced draft fan steam turbine; a first outlet end, communicated with the first inlet end, of the turbine condenser is communicated with a second inlet end of the main engine condenser through a water conveying pipeline; the heat recovery pipeline comprises a water inlet pipeline and a water return pipeline, the water inlet pipeline is used for conveying cooling water to the second inlet end of the steam turbine condenser, and the second outlet end, communicated with the second inlet end, of the steam turbine condenser is communicated with a low-pressure heater set through the water return pipeline. By means of the technical scheme, waste heat of the steam turbine condenser can be recycled so as to reduce hot end loss.

Description

Technical Field

[0001] The present disclosure relates to the technical field of thermal power generation, and in particular to a steam-driven induced draft fan waste heat utilization system and a thermal power generator set. Background Art

[0002] With the improvement of steam parameters and unit capacity in thermal power plants, as well as the expansion of the overall scale of the power grid, the number of supercritical and ultra-supercritical units in the 600MW class and even higher capacity (1000MW) with increasingly mature technology has gradually increased in China. At the same time, the capacity of auxiliary equipment for high-parameter, large-capacity units has also increased, and induced draft fans have become one of the largest auxiliary power loads in power plants.

[0003] In the related art, in thermal power plants using steam-driven induced draft fans in production enterprises, the induced draft fan steam turbine is of condensing type and the cooling method adopts circulating water cooling. The exhaust steam enthalpy value of the induced draft fan steam turbine is relatively high, and the exhaust steam heat is carried into the cooling tower through the circulating water, resulting in a large heat loss. Utility Model Content

[0004] The purpose of the present disclosure is to provide a steam-driven induced draft fan waste heat utilization system and a thermal power generator set, which can realize the heat recycling of the induced draft fan steam turbine, so as to at least partially solve the above technical problems.

[0005] In order to achieve the above-mentioned object, according to a first aspect of the present disclosure, a steam-driven induced draft fan waste heat utilization system is provided, comprising:

[0006] Induced draft fan steam turbine, used to drive the induced draft fan;

[0007] a steam turbine condenser, wherein a first inlet end of the steam turbine condenser is connected to an exhaust outlet of the induced draft fan steam turbine;

[0008] A main engine condenser, wherein the first outlet end of the turbine condenser, which is in communication with the first inlet end, is in communication with the second inlet end of the main engine condenser via a water pipeline;

[0009] The heat recovery pipeline includes an inlet pipeline and a return pipeline. The second outlet end of the main engine condenser connected to the second inlet end is connected to the second inlet end of the turbine condenser through the inlet pipeline, and the second outlet end of the turbine condenser connected to the second inlet end is connected to the low-pressure heater group through the return pipeline.

[0010] Optionally, the first outlet end of the main engine condenser is connected to the second inlet end of the turbine condenser through a water inlet pipeline.

[0011] Optionally, the low-pressure heater group includes a plurality of low-pressure heaters connected in sequence, and the return water pipeline is connected to the low-pressure heater arranged at the front end.

[0012] Optionally, a shaft seal cooler is provided on the water inlet pipeline.

[0013] Optionally, the steam-driven induced draft fan waste heat utilization system includes a water storage structure, which is connected to the first outlet end of the main engine condenser to store cooling water.

[0014] Optionally, the water storage structure is connected in parallel to the water inlet pipeline through a water storage pipeline.

[0015] Optionally, the water storage pipeline includes a first branch and a second branch, the first branch is used to draw water from the water inlet pipeline to the water storage structure, and the second branch is used to return water from the water storage structure to the water inlet pipeline, a first stop valve is provided on the first branch, and a second stop valve is provided on the second branch, and the first stop valve and the second stop valve are in a normally closed state.

[0016] Optionally, a temperature sensor is provided on the steam turbine condenser, and / or a flow sensor is provided on the water inlet pipeline.

[0017] Optionally, the steam-driven induced draft fan waste heat utilization system also includes a controller, the temperature sensor is connected to the first stop valve and the second stop valve through the controller signal, and / or the flow sensor is connected to the first stop valve and the second stop valve through the controller signal.

[0018] According to a second aspect of the present disclosure, a thermal power generating set is provided, comprising a main steam turbine, a boiler, a generator, an induced draft fan, a low-pressure heater group, and the above-mentioned steam-driven induced draft fan waste heat utilization system.

[0019] Through the above technical solution, the waste heat of the steam turbine condenser can be recycled to reduce heat-end losses. Specifically, the exhaust outlet of the induced draft fan steam turbine is connected to the first inlet end of the steam turbine condenser so that higher-temperature steam can enter the first heat exchange flow channel of the steam turbine condenser. The water inlet pipeline is connected to the second inlet end of the steam turbine condenser to transport cooling water into the second heat exchange flow channel of the steam turbine condenser, thereby allowing the cooling water in the second heat exchange flow channel to exchange heat with the higher-temperature steam in the first heat exchange flow channel. The return water pipeline is then connected to the second outlet end of the steam turbine condenser and the low-pressure heater group to transport this part of the heat-exchanged cooling water to the low-pressure heater group, thereby reducing the amount of heat added to the water in the preheating boiler of the low-pressure heater group, improving thermal efficiency, and reducing energy consumption. In addition, the higher temperature steam in the first heat exchange flow channel of the turbine condenser is cooled into water after heat exchange and transported to the second inlet end of the main engine condenser through the water pipeline, and then this part of the cooling water enters the second heat exchange flow channel of the main engine condenser to be used for heat exchange of the main engine condenser, thereby realizing the cooling and reuse of this part of the cooling water to reduce losses.

[0020] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0022] Figure 1 1 is a flow chart of a steam-driven induced draft fan waste heat utilization system provided in an exemplary embodiment of the present disclosure.

[0023] Description of Reference Numerals

[0024] 1. Induced draft fan turbine; 2. Turbine condenser; 21. Temperature sensor; 3. Heat recovery pipeline; 31. Water inlet pipeline; 311. Flow sensor; 32. Return water pipeline; 4. Main engine condenser; 5. Shaft seal cooler; 6. Water storage structure; 7. Water storage pipeline; 71. First branch; 711. First stop valve; 72. Second branch; 721. Second stop valve; 8. Controller; 9. Induced draft fan; 10. Low-pressure heater group. DETAILED DESCRIPTION

[0025] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0026] In this disclosure, unless otherwise specified, "inside" and "outside" refer to the inside and outside of the corresponding component's outline; "far" and "near" refer to the spatial distance of the corresponding component relative to another component. Furthermore, the terms "first," "second," and so on, used in this disclosure, are intended to distinguish one element from another and do not convey sequential or significant meanings. In the following description, unless otherwise indicated, identical numerals in different figures represent identical or similar elements.

[0027] According to the first aspect of the present disclosure, referring to Figure 1 As shown, the present disclosure provides a waste heat utilization system of a steam-driven induced draft fan 9, comprising:

[0028] An induced draft fan steam turbine 1, used to drive an induced draft fan 9;

[0029] The steam turbine condenser 2 has a first inlet end connected to the exhaust outlet of the induced draft fan steam turbine 1;

[0030] The main engine condenser 4, the first outlet end of the turbine condenser 2 connected to the first inlet end is connected to the second inlet end of the main engine condenser 4 through a water pipeline;

[0031] The heat recovery pipeline 3 includes an inlet pipeline 31 and a return pipeline 32. The second outlet end of the main engine condenser 4 connected to the second inlet end is connected to the second inlet end of the turbine condenser 2 through the inlet pipeline 31, and the second outlet end of the turbine condenser 2 connected to the second inlet end is connected to the low-pressure heater group 10 through the return pipeline 32.

[0032] Through the above technical solution, the waste heat of the steam turbine condenser 2 can be recycled to reduce the loss at the hot end. Specifically, the exhaust outlet of the induced draft fan steam turbine 1 is connected to the first inlet end of the steam turbine condenser 2 so that the higher temperature steam can enter the first heat exchange flow channel of the steam turbine condenser 2. The water inlet pipe 31 is connected to the second inlet end of the steam turbine condenser 2 for conveying cooling water into the second heat exchange flow channel of the steam turbine condenser 2, thereby allowing the cooling water in the second heat exchange flow channel to exchange heat with the higher temperature steam in the first heat exchange flow channel. Then, the return water pipe 32 is connected to the second outlet end of the steam turbine condenser 2 and the low-pressure heater group 10 to convey this part of the heat-exchanged cooling water to the low-pressure heater group 10, thereby reducing the amount of heat used by the low-pressure heater group 10 to preheat the water in the boiler, improving thermal efficiency and reducing energy consumption. In addition, the higher temperature steam in the first heat exchange flow channel of the turbine condenser 2 is cooled into water after heat exchange and transported to the second inlet end of the main engine condenser 4 through the water pipeline, and then this part of the cooling water enters the second heat exchange flow channel of the main engine condenser 4 to be used for heat exchange in the main engine condenser 4, thereby realizing the cooling and reuse of this part of the cooling water to reduce losses.

[0033] In some embodiments, reference Figure 1 As shown, the first outlet end of the main engine condenser 4 can be connected to the second inlet end of the turbine condenser 2 through the water inlet pipeline 31. In this way, the cooling water used for heat exchange with the higher temperature steam in the first heat exchange flow channel of the turbine condenser 2 comes from the main engine condenser 4. It can be understood that the first outlet end of the main engine condenser 4 is connected to the first heat exchange flow channel of the main engine condenser 4. The higher temperature steam in the first heat exchange flow channel of the turbine condenser 2 is cooled into water after heat exchange and is transported to the second inlet end of the main engine condenser 4 through the water pipeline. Then, this part of the cooling water enters the second heat exchange flow channel of the main engine condenser 4 for heat exchange with the higher temperature steam in the first heat exchange flow channel of the main engine condenser 4. Then, the higher temperature steam in the first heat exchange flow channel of the main engine condenser 4 is cooled into water after heat exchange and is transported to the second inlet end of the turbine condenser 2 through the water inlet pipeline 31 for heat exchange with the higher temperature steam in the first heat exchange flow channel of the turbine condenser 2 to recover the waste heat of the turbine condenser 2.

[0034] It is understandable that the cooling water delivered to the second inlet end of the steam turbine condenser 2 through the water inlet pipe 31 may also be external water, such as seawater, etc., and the present disclosure is not limited thereto.

[0035] In some embodiments, reference Figure 1 As shown, the low-pressure heater group 10 may include multiple low-pressure heaters connected in sequence, and the return water pipe 32 is connected to the low-pressure heater arranged at the front end. In this way, the thermal efficiency and economy of the entire system can be improved by the low-pressure heater group 10. Specifically, multiple low-pressure heaters can be arranged in series in the thermal cycle system of thermal power generation. Multiple low-pressure heaters reduce the amount of water heated in the boiler by preheating the feed water, thereby improving the efficiency of the entire thermal cycle. At the same time, by reducing the amount of water heated, the evaporation pressure inside the boiler can be reduced, thereby improving the steam quality. The present disclosure exemplarily connects the return water pipe 32 to the low-pressure heater arranged at the front end, that is, the low-pressure heater at the most upstream among the multiple low-pressure heaters in the low-pressure heater group 10, so as to make full use of the higher temperature water transported through the return water pipe 32 after self-heating in the turbine condenser 2.

[0036] Furthermore, in some other possible alternative embodiments not shown in the drawings, the return water line 32 may also be connected to any one or more of the multiple low-pressure heaters in the low-pressure heater group 10, and the present disclosure is not limited thereto. Of course, multiple low-pressure heaters may also be arranged in parallel in the thermal cycle system of a thermal power generation system, and the present disclosure is not specifically limited thereto.

[0037] In some embodiments, reference Figure 1 As shown, a shaft seal cooler 5 can be provided on the water inlet pipe 31. Thus, the shaft seal cooler 5 can cool and recover steam escaping from the shaft seal of the main engine condenser 4, thereby reducing steam loss and improving the thermal efficiency of the system. The shaft seal cooler 5 cools this steam and converts it into condensed water, thereby recovering the steam's energy, reducing the loss of steam directly discharged into the atmosphere, and improving the overall thermal efficiency of the system. At the same time, the shaft seal cooler 5 can reduce the potential danger of steam to personnel and equipment by cooling the escaping steam. Therefore, the provision of the shaft seal cooler 5 can reduce energy waste and help improve the overall performance, economy, and safety of the system.

[0038] In some embodiments, reference Figure 1As shown, the waste heat utilization system of the steam-driven induced draft fan 9 may include a water storage structure 6, which is connected to the first outlet end of the main engine condenser 4 to store cooling water. In this way, the water storage structure 6 can be used to temporarily store the cooling water output from the first outlet end of the main engine condenser 4, so as to store excess cooling water to the water storage structure 6 when the cooling water output from the first outlet end of the main engine condenser 4 meets and exceeds the heat exchange demand of the turbine condenser 2, and can release the stored cooling water to meet the heat exchange demand of the turbine condenser 2 when the cooling water output from the first outlet end of the main engine condenser 4 cannot meet the heat exchange demand of the turbine condenser 2.

[0039] It is understandable that the water storage structure 6 can be arranged in any suitable manner. In some exemplary embodiments, referring to Figure 1 As shown, the water storage structure 6 can be connected in parallel to the water inlet pipeline 31 via the water storage pipeline 7. In this way, when the cooling water output from the first outlet of the main engine condenser 4 can meet and exceed the heat exchange requirements of the steam turbine condenser 2, some of the cooling water in the water inlet pipeline 31 can be transported to the water storage structure 6 via the water storage pipeline 7 to be stored in the water storage structure 6 for future use. When the cooling water output from the first outlet of the main engine condenser 4 cannot meet the heat exchange requirements of the steam turbine condenser 2, the cooling water in the water storage structure 6 can be transported to the water inlet pipeline 31 via the water storage pipeline 7, and then transported together with the existing cooling water in the water inlet pipeline 31 to the second inlet of the steam turbine condenser 2 for heat exchange with higher temperature steam.

[0040] In some embodiments, reference Figure 1 As shown, the water storage pipeline 7 may include a first branch 71 and a second branch 72, wherein the first branch 71 is used to draw water from the water inlet pipeline 31 to the water storage structure 6, and the second branch 72 is used to return water from the water storage structure 6 to the water inlet pipeline 31. A first stop valve 711 is provided on the first branch 71, and a second stop valve 721 is provided on the second branch 72. The first stop valve 711 and the second stop valve 721 are in a normally closed state.

[0041] In this way, when the cooling water output from the first outlet of the main engine condenser 4 can normally meet the heat exchange demand of the turbine condenser 2, the first stop valve 711 and the second stop valve 721 are in a closed state. When the cooling water output from the first outlet of the main engine condenser 4 can meet and exceed the heat exchange demand of the turbine condenser 2, the first stop valve 711 is opened and the second stop valve 721 is closed, and a portion of the cooling water in the water inlet pipeline 31 is transported to the water storage structure 6 via the first branch 71 for storage in the water storage structure 6 for future use. When the cooling water output from the first outlet of the main engine condenser 4 cannot meet the heat exchange demand of the turbine condenser 2, the first stop valve 711 is closed and the second stop valve 721 is opened, and the cooling water in the water storage structure 6 is transported to the water inlet pipeline 31 via the second branch 72, and then transported together with the existing cooling water in the water inlet pipeline 31 to the second inlet of the turbine condenser 2 for heat exchange with higher temperature steam, thereby meeting the heat exchange demand of the turbine condenser 2.

[0042] It can be understood that in some other possible alternative embodiments not shown in the accompanying drawings, the first branch 71 can be directly connected to the first outlet end of the main engine condenser 4 and the water storage structure 6, and the second branch 72 can be directly connected to the water storage structure 6 and the second inlet end of the turbine condenser 2, but the present disclosure is not limited to this.

[0043] In some embodiments, reference Figure 1 As shown, the steam turbine condenser 2 may be provided with a temperature sensor 21, and / or the water inlet pipe 31 may be provided with a flow sensor 311. Thus, the temperature of the first heat exchange flow channel of the steam turbine condenser 2 may be detected by the temperature sensor 21 to monitor the heat exchange between the cooling water in the second heat exchange flow channel of the steam turbine condenser 2 and the higher-temperature steam in the first heat exchange flow channel. Furthermore, the cooling water flow in the water inlet pipe may be detected by the flow sensor 311.

[0044] The present disclosure exemplarily provides a temperature sensor 21 on the steam turbine condenser 2 and a flow sensor 311 on the water inlet pipe 31. Exemplarily, when the temperature sensor 21 detects a low temperature in the first heat exchange channel and the flow sensor 311 detects a high cooling water flow in the water inlet pipe, the first stop valve 711 can be opened to transfer a portion of the cooling water in the water inlet pipe 31 to the water storage structure 6 via the first branch 71 for storage in the water storage structure 6 for future use. When the temperature sensor 21 detects a low temperature in the first heat exchange channel and the flow sensor 311 detects a low cooling water flow in the water inlet pipe, the first stop valve 711 and the second stop valve 721 remain normally closed. When the temperature sensor 21 detects that the temperature of the first heat exchange channel is high, the second stop valve 721 can be opened, and the cooling water in the water storage structure 6 can be transported to the water inlet pipe 31 through the second branch 72, and then transported together with the original cooling water in the water inlet pipe 31 to the second inlet end of the turbine condenser 2 for heat exchange of higher temperature steam, thereby meeting the heat exchange requirements of the turbine condenser 2.

[0045] In some embodiments, reference Figure 1 As shown, the waste heat utilization system of the steam-driven induced draft fan 9 may further include a controller 8, wherein the temperature sensor 21 is connected to the first stop valve 711 and the second stop valve 721 via signals from the controller 8, and / or the flow sensor 311 is connected to the first stop valve 711 and the second stop valve 721 via signals from the controller 8. Thus, by providing the controller 8 to facilitate control of the opening and closing of the first stop valve 711 and the second stop valve 721, the present disclosure exemplarily connects both the temperature sensor 21 and the flow sensor 311 to the first stop valve 711 and the second stop valve 721 via signals from the controller 8.

[0046] For example, when the temperature sensor 21 detects that the temperature of the first heat exchange channel is low and the flow sensor 311 detects that the cooling water flow in the water inlet pipe is large, the temperature sensor 21 and the flow sensor 311 transmit signals to the controller 8, and then the controller 8 transmits signals to the first stop valve 711 and the second stop valve 721, so that the first stop valve 711 changes from a closed state to an open state, and the second stop valve 721 remains in a closed state, so as to transport part of the cooling water in the water inlet pipe 31 to the water storage structure 6 through the first branch 71, so as to be stored in the water storage structure 6 for standby use. When the temperature sensor 21 detects that the temperature of the first heat exchange channel is high, the temperature sensor 21 and the flow sensor 311 transmit signals to the controller 8, and then the controller 8 transmits signals to the first stop valve 711 and the second stop valve 721, so that the second stop valve 721 changes from a closed state to an open state, and the first stop valve 711 remains in a closed state, and the cooling water in the water storage structure 6 is transported to the water inlet pipe 31 through the second branch 72, and then transported together with the original cooling water in the water inlet pipe 31 to the second inlet end of the turbine condenser 2 for heat exchange of higher temperature steam, thereby meeting the heat exchange requirements of the turbine condenser 2.

[0047] According to a second aspect of the present disclosure, a thermal power generator set is provided, comprising a main steam turbine, a boiler, a generator, an induced draft fan 9, a low-pressure heater group 10, and the aforementioned waste heat recovery system for the steam-driven induced draft fan 9. Thus, high-temperature flue gas is generated by the combustion of fuel in the boiler. During this process, the induced draft fan 9 introduces fresh air from outside into the boiler furnace, providing the necessary oxygen for the combustion of the fuel. The high-temperature flue gas then heats water in the boiler to generate high-temperature, high-pressure steam. The high-temperature steam drives the main steam turbine, which in turn drives the generator to generate electricity. The steam exhausted from the main steam turbine is then cooled and condensed into water in the main engine condenser 4. This water is transported via the water inlet pipe 31 of the waste heat recovery system for the steam-driven induced draft fan 9 to the second inlet end of the steam turbine condenser 2 for heat exchange with the exhaust steam from the induced draft fan steam turbine 1 to recover this waste heat. This heat-exchanged water is then transported via the return water pipe 32 to the low-pressure heater group 10, which preheats this water for recycling back into the boiler for reuse.

[0048] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0049] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0050] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A steam-driven induced draft fan waste heat utilization system, characterized in that: include: Induced draft fan steam turbine, used to drive the induced draft fan; a steam turbine condenser, wherein a first inlet end of the steam turbine condenser is connected to an exhaust outlet of the induced draft fan steam turbine; A main engine condenser, wherein the first outlet end of the turbine condenser, which is in communication with the first inlet end, is in communication with the second inlet end of the main engine condenser via a water pipeline; as well as The heat recovery pipeline includes an inlet pipeline and a return pipeline. The inlet pipeline is used to transport cooling water to the second inlet end of the turbine condenser. The second outlet end of the turbine condenser connected to the second inlet end is connected to the low-pressure heater group through the return pipeline.

2. The steam-driven induced draft fan waste heat utilization system according to claim 1, characterized in that: The first outlet end of the main engine condenser is connected to the second inlet end of the turbine condenser through a water inlet pipeline.

3. The steam-driven induced draft fan waste heat utilization system according to claim 2, characterized in that: The low-pressure heater group includes a plurality of low-pressure heaters connected in sequence, and the return water pipeline is connected to the low-pressure heater arranged at the front end.

4. The steam-driven induced draft fan waste heat utilization system according to claim 2, characterized in that: A shaft seal cooler is provided on the water inlet pipeline.

5. The steam-driven induced draft fan waste heat utilization system according to claim 2, characterized in that: The steam-driven induced draft fan waste heat utilization system includes a water storage structure, which is connected to the first outlet end of the main engine condenser to store cooling water.

6. The steam-driven induced draft fan waste heat utilization system according to claim 5, characterized in that: The water storage structure is connected in parallel to the water inlet pipeline through a water storage pipeline.

7. The steam-driven induced draft fan waste heat utilization system according to claim 6, characterized in that: The water storage pipeline includes a first branch and a second branch. The first branch is used to draw water from the water inlet pipeline to the water storage structure, and the second branch is used to return water from the water storage structure to the water inlet pipeline. A first stop valve is provided on the first branch, and a second stop valve is provided on the second branch. The first stop valve and the second stop valve are in a normally closed state.

8. The steam-driven induced draft fan waste heat utilization system according to claim 7, characterized in that: The steam turbine condenser is provided with a temperature sensor, and / or the water inlet pipeline is provided with a flow sensor.

9. The steam-driven induced draft fan waste heat utilization system according to claim 8, characterized in that: The steam-driven induced draft fan waste heat utilization system also includes a controller, the temperature sensor is connected to the first stop valve and the second stop valve through the controller signal, and / or the flow sensor is connected to the first stop valve and the second stop valve through the controller signal.

10. A thermal power generating set, characterized in that: The invention comprises a main steam turbine, a boiler, a generator, an induced draft fan, a low-pressure heater group and the steam-driven induced draft fan waste heat utilization system according to any one of claims 1 to 9.

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