A thermal power plant circulating cooling water waste heat recycling system and a working method thereof

Abstract

The application provides a thermal power station circulating cooling water waste heat recycling system and a working method thereof. The system uses waste heat generated by cooling of thermal power station equipment to heat raw water or desalted water, improves water production capacity of the desalted water, and reduces circulating water pollution. A coagulation sedimentation tank, a filter tank and a water storage tank are connected in sequence. A temperature detector is installed on an inlet pipe of the filter tank. The water storage tank is connected with a production water supply system, a desalted water production system and a desalted circulating water supply pipe. An outlet bypass pipe is connected with the coagulation sedimentation tank and a cooling tower. A backwater bypass pipe is connected with the coagulation sedimentation tank and a circulating water backwater main pipe. Temperature detectors and regulating valves are installed on the outlet bypass pipe and the backwater bypass pipe. A desalted circulating backwater pipe is connected with the desalted water production system and the circulating water backwater main pipe. A desalted circulating water supply pipe is connected with a circulating water supply main pipe. Isolation valves are installed on the desalted circulating water supply pipe, the desalted circulating backwater pipe, the circulating water supply main pipe and the circulating water backwater main pipe.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of thermal power station circulating cooling water waste heat recycling system and its working method. BACKGROUND

[0002] At present, energy-saving and carbon reduction promote low carbonization and waste heat recovery technology, is one of important means to promote energy utilization in China and help achieve the "double carbon" goal. Central heating and other cogeneration power plants in park eliminate inefficient small boilers, improve coal efficiency, and are encouraged and supported by national policy projects.

[0003] Because thermal power station supplies steam to the outside, the recovery rate of desalted water is low, and a large amount of desalted water needs to be prepared. To reduce the pollution of acid and alkali to the environment, the desalted water preparation system usually uses membrane method, and the membrane method process has strict requirements for the temperature of the inlet raw water, which needs a suitable working temperature range (generally 25℃±5℃). If the temperature is lower than or higher than this temperature range, especially in winter, the raw water temperature is only 5℃, the water production rate of the system is greatly reduced, and the water production cannot be guaranteed, which will force the operation load to be reduced, and in severe cases, it will endanger the safe operation of the system. To meet the output requirements of the desalted water preparation system, a raw water steam heating system needs to be set up to heat the raw water to a certain temperature in the season when the water temperature is low. According to the calculation, a 500 tons / hour raw water needs to consume nearly 10 million yuan in heating energy in the winter in the north.

[0004] On the other hand, the cooling water of the park heating power station cools down high-temperature equipment or condenser exhaust steam to produce a large amount of high-temperature circulating water (20~30℃ in winter, about 40℃ in summer), which is currently cooled by mechanical or natural cooling towers, and the heat is directly discharged into the air, which not only causes waste of heat and evaporation water resources, but also brings about the operation power consumption of circulating water pumps and cooling towers and other equipment.

[0005] At present, back pressure machines are commonly used in cogeneration power plants, and the cooling of a single steam turbine generator and auxiliary equipment is 300~400t / h, which matches the raw water quantity of desalted water preparation, and has the condition of fully utilizing the waste heat of cooling water.

[0006] Therefore, it is necessary to design a cooling water system waste heat recycling system for raw water and desalted water heating and control system, realize waste heat recycling, and achieve energy saving and water saving. SUMMARY

[0007] The present application aims to overcome the above-mentioned deficiencies in the prior art, and provides a kind of thermal power station circulating cooling water waste heat recycling system and its working method with reasonable structure design, which uses the waste heat generated by the cooling of thermal power station equipment to heat raw water or desalted water, improves the desalted water preparation capacity, reduces the circulating water pollution, and realizes energy saving and water saving.

[0008] The application solves the above problems by adopting the technical scheme of a thermal power station circulating cooling water waste heat recycling system, which comprises a circulating cooling water system, the circulating cooling water system comprising a cooling tower, a circulating water supply main pipe, a circulating water return main pipe and a circulating water pump; one end of the circulating water supply main pipe is connected with a water outlet pipe of the cooling tower, and the other end is connected with a device needing to be cooled in the power station; the circulating water pump is installed on the circulating water supply main pipe; one end of the circulating water return main pipe is connected with a water return pipe of the cooling tower, and the other end is connected with the device needing to be cooled in the power station; the system is characterized in that it further comprises a desalted water raw water purification water supply system, the desalted water raw water purification water supply system comprising a raw water taking pump, a coagulation sedimentation tank, a filter tank, a water storage tank, a sedimentation tank water outlet pipe valve and a filter inlet pipe temperature detector; the circulating cooling water system further comprises a water outlet bypass pipe, a water outlet bypass pipe regulating valve, a water outlet bypass pipe temperature detector, a water return bypass pipe, a water return bypass pipe temperature detector, a water return bypass pipe regulating valve, a desalted circulating water supply pipe, a desalted circulating water supply pipe isolation valve, a desalted circulating water return pipe and a desalted circulating water return pipe isolation valve; the water inlet pipe of the coagulation sedimentation tank is connected with the raw water taking pump; the water outlet pipe of the coagulation sedimentation tank is connected with the water inlet pipe of the filter tank; the sedimentation tank water outlet pipe valve is installed on the water outlet pipe of the coagulation sedimentation tank; the filter inlet pipe temperature detector is installed on the water inlet pipe of the filter tank; the water outlet pipe of the filter tank is connected with the water inlet pipe of the water storage tank; the water outlet pipe of the water storage tank is divided into three routes; the first route is connected with a production water supply system; the second route is connected with a desalted water making system; and the third route is connected with the desalted circulating water supply pipe; one end of the water outlet bypass pipe is connected with the water outlet pipe of the coagulation sedimentation tank, and the other end is connected with the cooling tower; the water outlet bypass pipe regulating valve and the water outlet bypass pipe temperature detector are installed on the water outlet bypass pipe; one end of the water return bypass pipe is connected with the water outlet pipe of the coagulation sedimentation tank, and the other end is connected with the circulating water return main pipe; the water return bypass pipe temperature detector and the water return bypass pipe regulating valve are installed on the water return bypass pipe; one end of the desalted circulating water return pipe is connected with the desalted water making system, and the other end is connected with the circulating water return main pipe; the desalted circulating water return pipe isolation valve is installed on the desalted circulating water return pipe; the desalted circulating water supply pipe is connected with the circulating water supply main pipe; the desalted circulating water supply pipe isolation valve is installed on the desalted circulating water supply pipe; the circulating water supply main pipe isolation valve is installed on the circulating water supply main pipe; and the circulating water return main pipe isolation valve is installed on the circulating water return main pipe.

[0009] The coagulation sedimentation tank is provided with a dosing area and a flocculation area; the flocculation area is connected with a flocculant dosing system; and the dosing area is connected with a coagulant dosing system.

[0010] The circulating water return main pipe is provided with a circulating water return main pipe flow detector and a circulating water return main pipe temperature detector.

[0011] The water outlet pipe of the coagulation sedimentation tank is provided with a sedimentation tank water outlet pipe flow meter.

[0012] The application is characterized in that the water storage tank temperature detector is installed on the water storage tank.

[0013] The first water outlet pipe of the water storage tank is connected with the production water supply system through a production water supply pump, the second water outlet pipe is connected with the desalination water supply system through a desalination direct water supply pump, and the third water outlet pipe is connected with the desalination circulating water supply pipe through a desalination circulating water supply pump.

[0014] The application is characterized in that the backwater bypass pipe flow detector is installed on the backwater bypass pipe.

[0015] The application is characterized in that the backwater bypass pipe is also connected with the flocculant dosing system.

[0016] The application is characterized in that the desalination circulating backwater pipe temperature detector is installed on the desalination circulating backwater pipe.

[0017] A working method of a thermal power station circulating cooling water waste heat recycling system is characterized by comprising the following steps:

[0018] (1) In summer or spring and autumn, when the river water temperature is high, or the circulating cooling water quantity of the thermal power station exceeds the desalination water supply quantity, in order to control the water temperature of the water storage tank, part of the backwater of the circulating water system is mixed with the outlet water of the sedimentation tank through the backwater bypass pipe to improve the water temperature of the water storage tank; the outlet water bypass pipe temperature detector, the backwater bypass pipe temperature detector and the filter inlet pipe temperature detector are monitored, and the outlet water bypass pipe regulating valve and the backwater bypass pipe regulating valve are adjusted to realize the control of the water temperature on the filter inlet pipe.

[0019] (2) In winter, when the river water temperature is low, and the circulating water quantity of the circulating cooling water system is close to the desalination water supply quantity, the outlet water bypass pipe regulating valve and the backwater bypass pipe regulating valve are closed, the sedimentation tank outlet valve is opened, and all the outlet water of the sedimentation tank enters the filter tank; at the same time, the cooling tower and the circulating water backwater main pipe isolation valve, the circulating water pump and the circulating water supply main pipe isolation valve are closed, and the desalination circulating water supply pump, the desalination circulating water supply pipe isolation valve and the desalination circulating backwater pipe isolation valve are opened, so that the desalination water raw water in the water storage tank enters the circulating water supply main pipe through the desalination circulating water supply pipe, the equipment needing to be cooled in the thermal power station is cooled, the backwater enters the desalination water supply system through the desalination circulating backwater pipe, and the desalination water is directly supplied.

[0020] Compared with the prior art, the present application has the following advantages and effects: different water supply operation modes are adopted according to different circulating water quantity, water temperature and water quality conditions, water supply is heated, and the energy-saving and carbon-reducing function of fully utilizing equipment waste heat is achieved; the high-level water outlet of the coagulation sedimentation tank is directly discharged to the cooling water pool, the circulating water backwater is used to utilize the excess pressure head of the cooling tower, and the filter is passed, so that the water level and water pressure difference are fully utilized; the desalination circulating water pump directly supplies the equipment cooling and heating, the functions of the desalination direct water supply pump and the circulating water pump are combined, the cooling tower operation is cancelled, the water supply and air contact is reduced, the water quality is improved, the system operation efficiency is optimized, and the system power consumption is reduced; the desalination water raw water and the circulating water system are connected in series, the circulating water system is supplemented with a large amount of water, the circulating water concentration multiple is reduced, the circulating water quality is improved (especially the hardness and chloride ion in the circulating water in the north), the equipment corrosion prevention requirement is reduced, the equipment material selection is optimized, the consumption of the bactericide, stabilizer and acid adding agent and the like in the circulating water is reduced or even cancelled, and the system operation environment is improved; in addition, the circulating water blowdown and evaporation loss are directly reduced, and the purposes of reducing blowdown and saving water are achieved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the embodiment of the present application.

[0022] Figure 2 It is Figure 1 It is a structural schematic diagram of the left side of the middle partition line A.

[0023] Figure 3 It is Figure 1 It is a structural schematic diagram of the right side of the middle partition line A. DETAILED DESCRIPTION

[0024] The present application will be further described in detail below in combination with the drawings and through embodiments, and the following embodiments are an explanation of the present application and the present application is not limited to the following embodiments.

[0025] First, the thermal power plant circulating cooling water waste heat recycling system of the embodiment of the present application comprises a desalination water raw water purification water supply system, a circulating cooling water system and a centralized control system 28.

[0026] The desalination water raw water purification water supply system comprises a raw water taking pump 1-1, a coagulation sedimentation tank 1-2, a filter tank 1-3, a water storage tank 1-4, a flocculant dosing system 1-5, a coagulant dosing system 1-6, a production water supply pump 1-7, a desalination direct water supply pump 1-8, a water storage tank temperature detector 1-9, a sedimentation tank outlet pipe flowmeter 4, a sedimentation tank outlet pipe valve 5, a sedimentation tank outlet check valve 6, a filter inlet water pipe temperature detector 15 and a desalination circulating water supply pump 17.

[0027] The circulating cooling water system comprises a cooling tower 2-1, a circulating water pump 2-2, a circulating water supply main pipe 2-3, a circulating water return main pipe 2-8, a circulating water supply main pipe isolation valve 2-9, a circulating water return main pipe flow detector 2-10, a circulating water return main pipe isolation valve 2-11, a water outlet bypass pipe 7, a water outlet bypass pipe regulating valve 8, a water outlet bypass pipe temperature detector 9, a water return bypass pipe 10, a water return bypass pipe flow detector 11, a water return bypass pipe temperature detector 12, a water return bypass pipe regulating valve 13, a water return bypass pipe check valve 14, a desalination circulating water supply pipe 18, a desalination circulating water supply pipe temperature detector 19, a desalination circulating water supply pipe flow detector 20, a desalination circulating water supply pipe isolation valve 21, a desalination circulating water supply pipe check valve 22, a desalination circulating water return pipe 24, a circulating water return main pipe temperature detector 23, a desalination circulating water return pipe isolation valve 25 and a desalination circulating water return pipe temperature detector 26.

[0028] The raw water intake pump 1-1 takes water from a river, the water inlet pipe of the coagulation sedimentation tank 1-2 is connected with the raw water intake pump 1-1, the water outlet pipe 3 of the coagulation sedimentation tank 1-2 is connected with the water inlet pipe 16 of the filter tank 1-3, and the sedimentation tank outlet pipe flow meter 4, the sedimentation tank outlet pipe valve 5 and the sedimentation tank outlet check valve 6 are installed on the water outlet pipe 3 of the coagulation sedimentation tank 1-2, and the filter inlet pipe temperature detector 15 is installed on the water inlet pipe 16 of the filter tank 1-3. The water outlet pipe of the filter tank 1-3 is connected with the water inlet pipe of the water storage tank 1-4, the water outlet pipe of the water storage tank 1-4 is divided into three routes, the first route is connected with the production water supply system of the thermal power plant through the production water supply pump 1-7, the second route is connected with the desalination water making system of the thermal power plant through the desalination direct water supply pump 1-8, and the third route is connected with the desalination circulating water supply pipe 18 through the desalination circulating water supply pump 17. The water storage tank temperature detector 1-9 is installed on the water storage tank 1-4.

[0029] The desalination circulating water supply pump 17 should be configured according to the circulating water flow, at least two sets of desalination circulating water supply pumps 17 should be provided for the purpose of ensuring the reliability of the system operation, and one set of desalination circulating water supply pump 17 is a backup. In addition to meeting the resistance of the cooling system such as the steam turbine oil cooler and the generator air cooler, the desalination circulating water supply pump 17 also needs to add the head of the desalination direct water supply pump 1-8 to realize the water supply to the desalination water making system. According to the desalination water making flow, the desalination direct water supply pump 1-8 is preferably operated in multiple sets, and when the water supply of the desalination circulating water supply pump 17 is insufficient, part of the desalination direct water supply pump 1-8 can be started to supplement.

[0030] The coagulation sedimentation tank 1-2 is a high-efficiency coagulation sedimentation treatment equipment, which is provided with a dosing area, a flocculation area, a sedimentation area and a sludge concentration area to ensure that the water quality meets the water quality requirements of the circulating water. The flocculant dosing system 1-5 is connected with the flocculation area of the coagulation sedimentation tank 1-2, and the coagulant dosing system 1-6 is connected with the dosing area of the coagulation sedimentation tank 1-2.

[0031] The one end of the outlet water bypass pipe 7 is connected with the outlet pipe 3 of the coagulation sedimentation tank 1-2, and the other end is connected with the water collecting tank of the cooling tower 2-1. The outlet water bypass pipe regulating valve 8 and the outlet water bypass pipe temperature detector 9 are installed on the outlet water bypass pipe 7. The high-level outlet water of the coagulation sedimentation tank 1-2 is used to supplement the water of the water collecting tank of the cooling tower 2-1 through the outlet water bypass pipe 7, so as to realize the water supplement of the circulating cooling water system, reduce the investment of the water pump for water supply, and save the energy consumption in operation.

[0032] The one end of the circulating water supply main pipe 2-3 is connected with the outlet pipe of the cooling tower 2-1, and the other end is connected with the equipment needing to be cooled in the power station. The circulating water pump 2-2 and the circulating water supply main pipe isolation valve 2-9 are installed on the circulating water supply main pipe 2-3. The one end of the circulating water return main pipe 2-8 is connected with the return pipe of the cooling tower 2-1, and the other end is connected with the equipment needing to be cooled in the power station. The circulating water return main pipe flow detector 2-10, the circulating water return main pipe isolation valve 2-11 and the circulating water return main pipe temperature detector 23 are installed on the circulating water return main pipe 2-8. In the embodiment, the equipment needing to be cooled in the power station is the power station auxiliary machine cooling system 2-4, the power station air compressor cooling system 2-5, the generator air cooler 2-6, the turbine oil cooler 2-7 and the like.

[0033] The one end of the return water bypass pipe 10 is connected with the outlet pipe 3 of the coagulation sedimentation tank 1-2, and the other end is connected with the circulating water return main pipe 2-8. The return water bypass pipe flow detector 11, the return water bypass pipe temperature detector 12, the return water bypass pipe regulating valve 13 and the return water bypass pipe check valve 14 are installed on the return water bypass pipe 10. Due to the influence of different seasonal temperatures on the circulating cooling water of the thermal power station, the required cooling water quantity is different. The return water bypass pipe regulating valve 13 is arranged on the return water bypass pipe 10, and the water quantity of the return water is adjusted, so that the water temperature of the water entering the filtering system is not more than 30℃, so as to realize that the water temperature of the water storage tank 1-4 is not over temperature, and the water production effect of the membrane is guaranteed. The return water bypass pipe check valve 14 arranged on the return water bypass pipe 10 prevents the filtered water from flowing back to the circulating water return main pipe 2-8.

[0034] The circulating water heated by the cooling systems of the equipment in the power station is mixed with the outlet water of the coagulation sedimentation tank 1-2, and then enters the filtering tank 1-3 for filtering treatment. The filtered clean water is discharged to the water storage tank 1-4. The return water bypass pipe 10 is also connected with the flocculant dosing system 1-5. When the DCS control system 28 monitors that the flow of the circulating water return main pipe flow detector 2-10 and the flow of the return water bypass pipe flow detector 11 are relatively large, that is, when the concentration ratio of the circulating water system is relatively high, the flocculant is regularly added to the return water bypass pipe 10. After being mixed through the pipeline, the flocculant enters the filtering tank 1-3, so as to improve the filtering effect.

[0035] The desalination circulating backwater pipe 24 is connected with the desalination water making system at one end and connected with the circulating water backwater main pipe 2-8 at the other end, and the desalination circulating backwater pipe isolation valve 25 and the desalination circulating backwater pipe temperature detector 26 are installed on the desalination circulating backwater pipe 24.

[0036] The desalination circulating water supply pipe 18 is connected with the circulating water supply main pipe 2-3, and the desalination circulating water supply pipe temperature detector 19, the desalination circulating water supply pipe flow detector 20, the desalination circulating water supply pipe isolation valve 21 and the desalination circulating water supply pipe check valve 22 are installed on the desalination circulating water supply pipe 18.

[0037] The centralized control system 28 is connected with the production water supply pump 1-7, the desalination direct water supply pump 1-8, the storage pool temperature detector 1-9, the cooling tower 2-1, the circulating water pump 2-2, the circulating water supply main pipe electric isolation valve 2-9, the circulating water backwater main pipe flow detector 2-10, the circulating water backwater main pipe electric isolation valve 2-11, the sediment pool outlet pipe flow meter 4, the sediment pool outlet pipe valve 5, the outlet bypass pipe regulating valve 8, the outlet bypass pipe temperature detector 9, the backwater bypass pipe flow detector 11, the backwater bypass pipe temperature detector 12, the backwater bypass pipe regulating valve 13, the filtration inlet pipe temperature detector 15, the desalination circulating water supply pump 17, the desalination circulating water supply pipe temperature detector 19, the desalination circulating water supply pipe flow detector 20, the desalination circulating water supply pipe isolation valve 21, the circulating water backwater main pipe temperature detector 23, the desalination circulating backwater pipe isolation valve 25 and the desalination circulating backwater pipe temperature detector 26, according to the feedback temperature and flow on each detector, the opening degree of the regulating valve on the bypass pipe is controlled, and the start and stop of various water pumps and the running state are monitored. The centralized control system 28 adopts the DCS system.

[0038] Secondly, the working method of the thermal power plant circulating cooling water waste heat recycling system of the embodiment of the present application comprises the following steps:

[0039] (1) In summer or spring and autumn, especially in summer, when the river water temperature is high (about 20℃), or the circulating cooling water quantity of the thermal power plant exceeds the desalination water making quantity, because the circulating water cooling water backwater temperature is about 30~40℃, in order to control the water temperature of the storage pool 1-4 at about 25℃, so as to realize the best water making efficiency of the desalination water, the backwater of part of the circulating water of the circulating cooling water system is mixed with the outlet water of the sediment pool 1-2 through the backwater bypass pipe 10, so as to improve the water temperature of the storage pool 1-4. The DCS control system 28 adjusts the outlet bypass pipe regulating valve 8 and the backwater bypass pipe regulating valve 13 by monitoring the outlet bypass pipe temperature detector 9, the backwater bypass pipe temperature detector 12 and the filtration inlet pipe temperature detector 15, so that the water temperature on the filtration inlet pipe 16 is not more than 30℃, and is preferably about 25℃.

[0040] In summer, especially when a large amount of backwater is in contact with air, or the concentration ratio of circulating cooling water exceeds 2, the quality of backwater is poor, and coagulant should be added in time to filter the raw water to improve the quality of the effluent.

[0041] (2) In winter, the river water temperature is low, and the circulating water quantity of the circulating cooling water system is close to the desalinated water supply quantity. The control system 28 closes the effluent bypass pipe regulating valve 8 and the backwater bypass pipe regulating valve 13, fully opens the sedimentation tank effluent valve 5, so that all the sedimentation tank effluent enters the filter tank 1-3; at the same time, the cooling tower 2-1 and the circulating water backwater main pipe isolation valve 2-11, the circulating water pump 2-2 and the circulating water supply main pipe isolation valve 2-9 are closed, the desalination circulating water supply pump 17, the desalination circulating water supply pipe isolation valve 21 and the desalination circulating water return pipe isolation valve 25 are opened, so that the desalinated water raw water in the water storage tank 1-4 enters the circulating water supply main pipe 2-3 through the desalination circulating water supply pipe 18, directly cools the equipment needing to be cooled in the power plant, avoids contact with air, improves the water temperature, and the backwater enters the desalinated water preparation system through the desalination circulating water return pipe 24, directly supplies desalinated water preparation, and achieves the purpose of waste heat backwater.

[0042] When the circulating water quantity is less than the desalinated water supply quantity in winter, the desalination direct water supply pump 1-8 can be opened to mix and combine with the hot water generated by the desalination circulating water supply pump 17 to supply water to the desalinated water preparation system, and guarantee the water supply.

[0043] In addition, it should be noted that the specific embodiments described in the specification, the shape of the components, the name taken, etc. can be different, and the above described in the specification is only an example of the structure of the present application. Any equivalent changes or simple changes made according to the structure, features and principles described in the patent concept of the present application are included in the protection scope of the present application. Those skilled in the art can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, as long as they do not deviate from the structure of the present application or exceed the scope defined by the present claims, which shall belong to the protection scope of the present application.

Claims

1. A waste heat recovery and utilization system for circulating cooling water in a thermal power plant, comprising a circulating cooling water system, the circulating cooling water system including a cooling tower, a circulating water supply header, a circulating water return header, and a circulating water pump; one end of the circulating water supply header is connected to the outlet pipe of the cooling tower, and the other end is connected to the equipment in the power plant that needs to be cooled; a circulating water pump is installed on the circulating water supply header; one end of the circulating water return header is connected to the return pipe of the cooling tower, and the other end is connected to the equipment in the power plant that needs to be cooled; characterized in that: It also includes a demineralized raw water purification and supply system, which includes a raw water intake pump, a coagulation sedimentation tank, a filter tank, a storage tank, a sedimentation tank outlet valve, and a filter inlet temperature sensor. The circulating cooling water system also includes an outlet bypass pipe, an outlet bypass regulating valve, an outlet bypass temperature sensor, a return bypass pipe, a return bypass temperature sensor, a return bypass regulating valve, a demineralized circulating water supply pipe, a demineralized circulating water supply pipe isolation valve, a demineralized circulating return water pipe, and a demineralized circulating return water pipe isolation valve. The inlet pipe of the coagulation sedimentation tank is connected to the raw water intake pump, and the coagulation sedimentation... The outlet pipe of the coagulation sedimentation tank is connected to the inlet pipe of the filtration tank. A sedimentation tank outlet pipe valve is installed on the outlet pipe of the coagulation sedimentation tank, and a filtration inlet pipe temperature detector is installed on the inlet pipe of the filtration tank. The outlet pipe of the filtration tank is connected to the inlet pipe of the water storage tank. The outlet pipe of the water storage tank is divided into three branches: the first branch is connected to the production water supply system, the second branch is connected to the demineralized water production system, and the third branch is connected to the demineralized circulating water supply pipe. One end of the outlet bypass pipe is connected to the outlet pipe of the coagulation sedimentation tank, and the other end is connected to the cooling tower. An outlet bypass pipe regulating valve and an outlet bypass pipe temperature detector are installed on the outlet bypass pipe. One end of the return water bypass pipe is connected to the outlet pipe of the coagulation sedimentation tank, and the other end is connected to the circulating water return main pipe. A return water bypass pipe temperature detector and a return water bypass pipe regulating valve are installed on the return water bypass pipe. One end of the desalination circulating return water pipe is connected to the desalination water treatment system, and the other end is connected to the circulating water return main pipe. A desalination circulating return water pipe isolation valve is installed on the desalination circulating return water pipe. The desalination circulating water supply pipe is connected to the circulating water supply main pipe. A desalination circulating water supply pipe isolation valve is installed on the desalination circulating water supply pipe. A circulating water supply main pipe isolation valve is installed on the circulating water supply main pipe, and a circulating water return main pipe isolation valve is installed on the circulating water return main pipe.

2. The waste heat recovery and utilization system for circulating cooling water in a thermal power plant according to claim 1, characterized in that: The coagulation sedimentation tank is equipped with a dosing zone and a flocculation zone; a flocculant dosing system is connected to the flocculation zone, and a coagulant aid dosing system is connected to the dosing zone.

3. The waste heat recovery and utilization system for circulating cooling water in a thermal power plant according to claim 1, characterized in that: A circulating water return head pipe flow detector and a circulating water return head pipe temperature detector are installed on the circulating water return head pipe.

4. The waste heat recovery and utilization system for circulating cooling water in a thermal power plant according to claim 1, characterized in that: A flow meter for the sedimentation tank outlet pipe is installed on the outlet pipe of the coagulation sedimentation tank.

5. The waste heat recovery and utilization system for circulating cooling water in a thermal power plant according to claim 1, characterized in that: A water storage tank temperature detector is installed on the water storage tank.

6. The waste heat recovery and utilization system for circulating cooling water in a thermal power plant according to claim 1, characterized in that: The water outlet pipe of the water storage tank has a first branch connected to the production water supply system via a production water supply pump, a second branch connected to the desalination water production system via a desalination direct water supply pump, and a third branch connected to the desalination circulating water supply pipe via a desalination circulating water supply pump.

7. The waste heat recovery and utilization system for circulating cooling water in a thermal power plant according to claim 1, characterized in that: The aforementioned return water bypass pipe is equipped with a return water bypass pipe flow detector.

8. The waste heat recovery and utilization system for circulating cooling water in a thermal power plant according to claim 2, characterized in that: The aforementioned return water bypass pipe is also connected to the flocculant dosing system.

9. The waste heat recovery and utilization system for circulating cooling water in a thermal power plant according to claim 1, characterized in that: Temperature detector for desalination circulation return water pipe on the desalination circulation return water pipe.

10. A method for operating a waste heat recovery and utilization system for circulating cooling water in a thermal power plant according to any one of claims 1-9, characterized in that: Includes the following steps: (1) In summer or spring and autumn, when the river water temperature is high, or when the circulating cooling water volume of the thermal power plant exceeds the demineralized water production volume, in order to control the water temperature of the storage tank, the return water of part of the circulating cooling water system is mixed with the effluent of the sedimentation tank through the return water bypass pipe to increase the water temperature of the storage tank; by monitoring the temperature detectors of the outlet bypass pipe, the return water bypass pipe, and the filter inlet pipe, the outlet bypass pipe regulating valve and the return water bypass pipe regulating valve are adjusted to control the water temperature on the filter inlet pipe. (2) In winter, the river water temperature is low and the circulating water volume of the circulating cooling water system is close to the desalinated water supply volume. Close the outlet bypass pipe regulating valve and the return water bypass pipe regulating valve, and open the sedimentation tank outlet valve so that all sedimentation tank outlet water enters the filter tank. At the same time, close the cooling tower and circulating water return water main pipe isolation valve, circulating water pump, and circulating water supply main pipe isolation valve, and open the desalinated circulating water supply pump, desalinated circulating water supply pipe isolation valve and desalinated circulating return water pipe isolation valve so that the desalinated raw water in the storage tank enters the circulating water supply main pipe through the desalinated circulating water supply pipe to cool the equipment that the power station needs to cool. The return water enters the desalinated water production system through the desalinated circulating return water pipe and directly supplies desalinated water production.

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