Thermal power station circulating cooling water waste heat recycling system and working method thereof

Abstract

According to the thermal power station circulating cooling water waste heat recycling system and the working method thereof, waste heat generated by cooling of thermal power station equipment is used for heating raw water or desalted water, the water production capacity of the desalted water is improved, and circulating water pollution discharge is reduced. The coagulative precipitation tank, the filter tank and the water storage tank are sequentially connected, and a temperature detector is mounted on a water inlet pipe of the filter tank; the water storage tank is respectively connected with the production water supply system, the desalted water production system and the desalted circulating water supply pipe; the water outlet by-pass pipe is connected with the coagulative precipitation tank and the cooling tower, the water return by-pass pipe is connected with the coagulative precipitation tank and the circulating water return main pipe, and the water outlet by-pass pipe and the water return by-pass pipe are respectively provided with a temperature detector and a regulating valve; the desalted water circulating water return pipe is connected with the desalted water production system and the circulating water return main pipe; the desalting circulating water supply pipe is connected with the circulating water supply main pipe; isolating valves are mounted on the desalting circulating water supply pipe, the desalting circulating water return pipe, the circulating water supply main pipe and the circulating water return main pipe.

Description

Technical Field

[0001] The invention relates to a thermal power station circulating cooling water waste heat recovery and utilization system and a working method thereof. Background Art

[0002] At present, energy conservation and carbon reduction, low carbonization and waste heat recovery and utilization technology are one of the important means to promote my country's energy utilization and help achieve the "dual carbon" goal. The cogeneration power station such as the park's centralized heating eliminates inefficient small boilers and improves coal-fired efficiency, which is encouraged and supported by national policies.

[0003] Thermal power stations supply steam to the outside, so the recovery rate of desalted water is low, and a large amount of desalted water needs to be newly produced. In order to reduce the pollution of acid and alkali to the environment, the desalted water preparation system usually adopts membrane method, and the membrane treatment process has strict requirements for the raw water temperature at the inlet, requiring a suitable working temperature range (generally 25℃±5℃). If it is lower than or higher than this temperature range, especially in winter, the raw water temperature is only 5℃, the system water production rate is greatly reduced, and the water production will not be guaranteed, resulting in insufficient water replenishment in the thermal system, which will force the operating load to be reduced, and in severe cases, it will endanger the safe operation of the system. In order to meet the output requirements of the desalted water preparation system, it is generally necessary to set up a raw water steam heating system to heat the raw water to a certain temperature in the season with lower water temperature. According to calculations, a 500 tons / hour raw water, in the northern winter, requires nearly 10 million yuan in heating energy.

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

[0005] At present, back pressure machines are often used in cogeneration power plants. The cooling capacity of a single steam turbine generator and auxiliary equipment is 300~400t / h, which matches the raw water volume of desalination water production and has the conditions to fully utilize the waste heat of cooling water.

[0006] Therefore, it is necessary to design a cooling water system waste heat recovery system for heating and controlling raw water and desalted water, so as to realize waste heat recovery and achieve energy and water conservation. Summary of the invention

[0007] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a thermal power plant circulating cooling water waste heat recovery and utilization system with a rational structural design and a working method thereof, which utilizes the waste heat generated by the cooling of thermal power plant equipment to heat raw water or desalted water, thereby improving the water production capacity of desalted water, reducing circulating water discharge, and achieving energy and water conservation.

[0008] The technical solution adopted by the present invention to solve the above-mentioned problem is: a thermal power plant circulating cooling water waste heat recovery and utilization system, including a circulating cooling water system, the circulating cooling water system including 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 to the outlet pipe of the cooling tower, and the other end is connected to the equipment to be cooled in the power station, and a circulating water pump is installed on the circulating water supply main pipe; one end of the circulating water return main pipe is connected to the return pipe of the cooling tower, and the other end is connected to the equipment to be cooled in the power station; it is characterized in that: it also includes a desalted raw water purification water supply system, The desalted water raw water purification water supply system includes a raw water intake pump, a coagulation sedimentation tank, a filter tank, a water storage tank, a sedimentation tank outlet pipe valve and a filter inlet pipe temperature detector; the circulating cooling water system also includes an outlet bypass pipe, an outlet bypass pipe regulating valve, an outlet bypass pipe temperature detector, a return water bypass pipe, a return water bypass pipe temperature detector, a return water bypass pipe regulating valve, a desalination circulation water supply pipe, a desalination circulation water supply pipe isolation valve, a desalination circulation return pipe and a desalination circulation return pipe isolation valve; the inlet pipe of the coagulation sedimentation tank is connected to the raw water intake pump, and the outlet pipe of the coagulation sedimentation tank is connected to the inlet pipe of the filter tank , a sedimentation tank outlet pipe valve is installed on the outlet pipe of the coagulation sedimentation tank, and a filter inlet pipe temperature detector is installed on the inlet pipe of the filter tank; the outlet pipe of the filter tank is connected to the inlet pipe of the water storage tank, and the outlet pipe of the water storage tank is divided into three routes, the first route is connected to the production water supply system, the second route is connected to the desalted water water making system, and the third route is connected to the desalination circulation 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 of the coagulation sedimentation tank One end of the desalination circulation return pipe is connected to the desalination water water production system, and the other end is connected to the circulating water return main pipe, and a return water bypass pipe temperature detector and a return water bypass pipe regulating valve are installed on the return bypass pipe; one end of the desalination circulation return pipe is connected to the desalination water water production system, and the other end is connected to the circulating water return main pipe, and a desalination circulation return pipe isolation valve is installed on the desalination circulation return pipe; the desalination circulation water supply pipe is connected to the circulating water supply main pipe, and a desalination circulation water supply pipe isolation valve is installed on the desalination circulation 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.

[0009] The coagulation sedimentation tank of the present invention is provided with a dosing zone and a flocculation zone; the flocculation zone is connected with a flocculant dosing system, and the dosing zone is connected with a coagulant aid dosing system.

[0010] The present invention installs a circulating water return main pipe flow detector and a circulating water return main pipe temperature detector on the circulating water return main pipe.

[0011] The present invention installs a sedimentation tank outlet pipe flowmeter on the outlet pipe of the coagulation sedimentation tank.

[0012] The present invention installs a water tank temperature detector on the water tank.

[0013] The outlet pipe of the water storage tank described in the present invention is connected to the production water supply system through a production water supply pump on the first route, connected to the desalted water water production system on the second route through a desalination direct supply water pump on the third route through a desalination circulation water supply pump on the desalination circulation water supply pipe on the third route.

[0014] The invention discloses that a return water bypass pipe flow detector is installed on the return water bypass pipe.

[0015] The water return bypass pipe of the present invention is also connected to a flocculant dosing system.

[0016] The present invention provides a desalination circulation water return pipe temperature detector on the desalination circulation water return pipe.

[0017] A working method of a thermal power station circulating cooling water waste heat recovery system, characterized in that it comprises the following steps: (1) In summer or spring and autumn, when the river water temperature is high, or the circulating cooling water volume of the thermal power station exceeds the desalted water production volume, in order to control the water temperature of the water storage tank, the return water of part of the circulating water of the circulating cooling water system is mixed with the outlet water of the sedimentation tank through the return water bypass pipe to increase the water temperature of the water storage tank; by monitoring the outlet water bypass pipe temperature detector, the return water bypass pipe temperature detector and the filter water inlet pipe temperature detector, the outlet water bypass pipe regulating valve and the return water bypass pipe regulating valve are adjusted to achieve the control of the water temperature on the filter water 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 desalted water supply volume. Close the outlet bypass pipe regulating valve and the return bypass pipe regulating valve, open the sedimentation tank outlet valve, and allow all the sedimentation tank outlet water to enter the filter tank; at the same time, close the cooling tower and the circulating water return main pipe isolation valve, the circulating water pump, and the circulating water supply main pipe isolation valve, open the desalination circulating water supply pump, the desalination circulating water supply pipe isolation valve, and the desalination circulating water return pipe isolation valve, and allow the desalination water in the storage tank to enter the circulating water supply main pipe through the desalination circulating water supply pipe to cool the equipment that needs to be cooled in the power station. The return water enters the desalination water production system through the desalination circulating water return pipe and directly supplies the desalination water production.

[0018] Compared with the prior art, the present invention has the following advantages and effects: according to different circulating water volumes, water temperatures and water qualities, different water supply operation modes are adopted to realize water supply temperature rise, so as to fully utilize the waste heat of the equipment for energy saving and carbon reduction; high-level water discharge from the coagulation sedimentation tank is adopted and directly discharged to the cooling water pool, and the circulating water return water is used to return to the cooling tower with sufficient pressure head and enter the filter, so as to fully utilize the water level and water pressure difference; a desalination circulating water supply pump is used to directly supply equipment for cooling and temperature rise, and the functions of the desalination direct supply water pump and the circulating water pump are combined, so as to cancel the operation of the cooling tower and reduce the contact between the water supply and the air , improve water quality, optimize system operation efficiency, and reduce system power consumption; use desalted raw water and circulating water system in series to achieve a large amount of water replenishment in the circulating water system, thereby reducing the concentration multiples of circulating water, improving the water quality of circulating water (especially reducing the hardness and chloride ions in circulating water in the north), reducing equipment anti-corrosion requirements, optimizing equipment material selection, and at the same time reducing or even eliminating the consumption of circulating water sterilizers, stabilizers, acidification and other agents, thereby improving the system's operating environment; in addition, it also directly reduces the discharge of pollutants and evaporation losses of circulating water, thereby achieving the purpose of reducing pollution and saving water. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of an embodiment of the present invention.

[0020] Figure 2 for Figure 1 Schematic diagram of the structure on the left side of the center dividing line A.

[0021] Figure 3 for Figure 1 Schematic diagram of the structure on the right side of the center dividing line A. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and by way of examples. The following examples are intended to explain the present invention but the present invention is not limited to the following examples.

[0023] 1. The thermal power plant circulating cooling water waste heat recovery and utilization system according to an embodiment of the present invention comprises a desalted raw water purification and water supply system, a circulating cooling water system and a centralized control system 28.

[0024] The desalted water raw water purification water supply system includes a raw water intake 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 aid dosing system 1-6, a production water supply pump 1-7, a desalination direct supply water pump 1-8, a water storage tank temperature detector 1-9, a sedimentation tank outlet pipe flow meter 4, a sedimentation tank outlet pipe valve 5, a sedimentation tank outlet check valve 6, a filter inlet pipe temperature detector 15 and a desalination circulation water supply pump 17.

[0025] The circulating cooling water system includes 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, an outlet bypass pipe 7, an outlet bypass pipe regulating valve 8, an outlet bypass pipe temperature detector 9, a return bypass pipe 10, a return bypass pipe flow detector 11, a return bypass pipe temperature detector 12, a return bypass pipe temperature detector 13, a return bypass pipe temperature detector 14, a return bypass pipe temperature detector 15, a return bypass pipe temperature detector 16, a return bypass pipe temperature detector 17, a return bypass pipe temperature detector 18, a return bypass pipe temperature detector 19, a return bypass pipe temperature detector 20, a return bypass pipe temperature detector 21, a return bypass pipe temperature detector 22, a return bypass pipe temperature detector 23, a return bypass pipe temperature detector Temperature detector 12, return water bypass pipe regulating valve 13, return water bypass pipe check valve 14, desalination circulating water supply pipe 18, desalination circulating water supply pipe temperature detector 19, desalination circulating water supply pipe flow detector 20, desalination circulating water supply pipe isolation valve 21, desalination circulating water supply pipe check valve 22, desalination circulating water return pipe 24, circulating water return main pipe temperature detector 23, desalination circulating water return pipe isolation valve 25 and desalination circulating water return pipe temperature detector 26.

[0026] The raw water intake pump 1-1 takes water from the river water, the water inlet pipe of the coagulation sedimentation tank 1-2 is connected to the raw water intake pump 1-1, the water outlet pipe 3 of the coagulation sedimentation tank 1-2 is connected to the water inlet pipe 16 of the filter tank 1-3, the water outlet pipe flow meter 4 of the sedimentation tank, the water outlet pipe valve 5 of the sedimentation tank and the water outlet check valve 6 of the sedimentation tank 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 to the water inlet pipe of the water storage tank 1-4, and the water outlet pipe of the water storage tank 1-4 is divided into three routes, the first route is connected to the production water supply system of the thermal power station through the production water supply pump 1-7, the second route is connected to the desalted water production system of the thermal power station through the desalination direct supply water pump 1-8, and the third route is connected to the desalination circulation water supply pipe 18 through the desalination circulation water supply pump 17. A water tank temperature detector 1-9 is installed on the water tank 1-4.

[0027] The desalination circulating water supply pump 17 should be configured according to the amount of circulating water. To ensure the reliability of system operation, there should be at least 2 pumps, and 1 pump should be a spare. In addition to overcoming the resistance of cooling systems such as turbine oil coolers and generator air coolers, the desalination circulating water supply pump 17 also needs to add the head of the desalination direct supply water pump 1-8 to supply water to the desalination water production system. According to the amount of desalination water production, it is advisable to operate multiple desalination direct supply water pumps 1-8. When the desalination circulating water supply pump 17 is insufficient, some desalination direct supply water pumps 1-8 can be activated for supplementation.

[0028] The coagulation sedimentation tank 1-2 is a high-efficiency coagulation sedimentation treatment equipment, which is equipped with a dosing area, a flocculation area, a sedimentation area and a sludge concentration area to ensure that the effluent water quality meets the water quality requirements of circulating water. The flocculant dosing system 1-5 is connected to the flocculation area of ​​the coagulation sedimentation tank 1-2, and the coagulant dosing system 1-6 is connected to the dosing area of ​​the coagulation sedimentation tank 1-2.

[0029] One end of the water outlet bypass pipe 7 is connected to the water outlet pipe 3 of the coagulation sedimentation tank 1-2, and the other end is connected to the water collection tank of the cooling tower 2-1. A water outlet bypass pipe regulating valve 8 and a water outlet bypass pipe temperature detector 9 are installed on the water outlet bypass pipe 7. The high-level water outlet of the coagulation sedimentation tank 1-2 is used to replenish the water collection tank of the cooling tower 2-1 through the water outlet bypass pipe 7, thereby replenishing the circulating cooling water system, reducing the investment in setting up a water pump for water supply, and saving energy consumption in operation.

[0030] One end of the circulating water supply main pipe 2-3 is connected to the outlet pipe of the cooling tower 2-1, and the other end is connected to the equipment that needs to be cooled in the power station. A circulating water pump 2-2 and a circulating water supply main pipe isolation valve 2-9 are installed on the circulating water supply main pipe 2-3. One end of the circulating water return main pipe 2-8 is connected to the return pipe of the cooling tower 2-1, and the other end is connected to the equipment that needs to be cooled in the power station. A circulating water return main pipe flow detector 2-10, a circulating water return main pipe isolation valve 2-11 and a circulating water return main pipe temperature detector 23 are installed on the circulating water return main pipe 2-8. In this embodiment, the equipment that needs to be cooled in the power station is the power station auxiliary equipment 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, etc.

[0031] One end of the return bypass pipe 10 is connected to the outlet pipe 3 of the coagulation sedimentation tank 1-2, and the other end is connected to the circulating water return main pipe 2-8. A return bypass pipe flow detector 11, a return bypass pipe temperature detector 12, a return bypass pipe regulating valve 13 and a return bypass pipe check valve 14 are installed on the return bypass pipe 10. Since the circulating cooling water of the thermal power station is affected by the temperature in different seasons, the required amount of cooling water is different. By setting the return bypass pipe regulating valve 13 on the return bypass pipe 10, the amount of return water is adjusted to achieve a water temperature of no more than 30°C entering the filtration system, so as to ensure that the water temperature of the water storage tank 1-4 does not exceed the temperature and ensure the water production effect of the membrane. The return bypass pipe check valve 14 set on the return bypass pipe 10 prevents the filtered water from flowing back to the circulating water return main pipe 2-8.

[0032] The circulating water heated by the cooling system of each equipment in the power station is mixed with the effluent of the coagulation sedimentation tank 1-2 and then enters the filter tank 1-3 for filtration treatment, and the filtered clean water is discharged to the water storage tank 1-4. The return water bypass pipe 10 is also connected to the flocculant dosing system 1-5. When the DCS control system 28 detects that the flow rate of the circulating water return main pipe flow detector 2-10 is significantly different from the flow rate of the return water bypass pipe flow detector 11, that is, when the concentration ratio of the circulating water system is relatively high, flocculants are regularly added to the return water bypass pipe 10, and after mixing in the pipeline, they enter the filter tank 1-3 to improve the filtering effect.

[0033] One end of the desalination circulation return pipe 24 is connected to the desalination water production system, and the other end is connected to the circulating water return main pipe 2-8. A desalination circulation return pipe isolation valve 25 and a desalination circulation return pipe temperature detector 26 are installed on the desalination circulation return pipe 24.

[0034] The desalination circulating water supply pipe 18 is connected to the circulating water supply main pipe 2-3, and 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 and a desalination circulating water supply pipe check valve 22 are installed on the desalination circulating water supply pipe 18.

[0035] Centralized control system 28 and production water supply pump 1-7, desalination direct supply water pump 1-8, water storage tank temperature detector 1-9, cooling tower 2-1, circulating water pump 2-2, circulating water supply main pipe electric isolation valve 2-9, circulating water return main pipe flow detector 2-10, circulating water return main pipe electric isolation valve 2-11, sedimentation tank outlet pipe flow meter 4, sedimentation tank outlet pipe valve 5, outlet bypass pipe regulating valve 8, outlet bypass pipe temperature detector 9, return bypass pipe flow detector 11, return bypass pipe temperature detector 12 , return water bypass pipe regulating valve 13, filter water inlet pipe temperature detector 15, desalination circulation water supply pump 17, desalination circulation water supply pipe temperature detector 19, desalination circulation water supply pipe flow detector 20, desalination circulation water supply pipe isolation valve 21, circulating water return main pipe temperature detector 23, desalination circulation return pipe isolation valve 25 and desalination circulation return pipe temperature detector 26 are connected. According to the feedback temperature and flow from each detector, the opening degree of the regulating valve on the bypass pipe is controlled, and the start and stop and operation status of various water pumps are monitored. The centralized control system 28 adopts the DCS system.

[0036] 2. The working method of the thermal power plant circulating cooling water waste heat recovery and utilization system according to the embodiment of the present invention comprises the following steps: (1) In summer or spring and autumn, especially in summer, when the river water temperature is high (about 20°C), or the circulating cooling water volume of the thermal power station exceeds the desalted water production volume, since the circulating cooling water return water temperature is about 30~40°C, in order to control the water temperature of the water storage tank 1-4 at about 25°C to achieve the best desalted water production efficiency, the return water of part of the circulating water of the circulating cooling water system is mixed with the effluent of the sedimentation tank 1-2 through the return water bypass pipe 10 to increase the water temperature of the water storage tank 1-4. The DCS control system 28 monitors the outlet bypass pipe temperature detector 9, the return water bypass pipe temperature detector 12 and the filter inlet pipe temperature detector 15, and adjusts the outlet bypass pipe regulating valve 8 and the return water bypass pipe regulating valve 13 to achieve that the water temperature on the filter inlet pipe 16 does not exceed 30°C, preferably about 25°C.

[0037] In summer, especially when a large amount of return water comes into contact with air, or when the concentration ratio of circulating cooling water exceeds 2, the return water quality is poor. Coagulant should be added in time to coagulate and filter the raw water to improve the water quality of the effluent.

[0038] (2) In winter, the river water temperature is low, and the circulating water volume of the circulating cooling water system is close to the desalted water supply volume. The control system 28 closes the outlet bypass pipe regulating valve 8 and the return bypass pipe regulating valve 13, and fully opens the sedimentation tank outlet valve 5, so that all the sedimentation tank outlet water enters the filter tank 1-3; at the same time, the cooling tower 2-1 and the circulating water return 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, and 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 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 that needs to be cooled in the power station, avoids contact with the air, and increases the water temperature. The return water enters the desalination water production system through the desalination circulating water return pipe 24, and directly supplies the desalination water production system, thereby achieving the purpose of waste heat return water.

[0039] When the amount of circulating water is less than the amount of desalted water supply in winter, the desalination direct supply water pump 1-8 can be turned on to mix the hot water produced by the desalination circulating water supply pump 17 and supply it to the desalted water production system to ensure water supply.

[0040] In addition, it should be noted that the shapes and names of the parts and components of the specific embodiments described in this specification may be different, and the above content described in this specification is only an example of the structure of the present invention. All equivalent changes or simple changes made based on the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. Technicians in the technical field of the present invention can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A thermal power station circulating cooling water waste heat recovery and utilization system, comprising 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 to the outlet pipe of the cooling tower, and the other end is connected to the equipment to be cooled in the power station, and a circulating water pump is installed on the circulating water supply main pipe; one end of the circulating water return main pipe is connected to the return pipe of the cooling tower, and the other end is connected to the equipment to be cooled in the power station; the characteristics are: It also includes a desalted water raw water purification water supply system, which includes a raw water intake pump, a coagulation sedimentation tank, a filter tank, a water storage tank, a sedimentation tank outlet pipe valve and a filter inlet pipe temperature detector; the circulating cooling water system also includes an outlet bypass pipe, an outlet bypass pipe regulating valve, an outlet bypass pipe temperature detector, a return bypass pipe, a return bypass pipe temperature detector, a return bypass pipe regulating valve, a desalination circulation water supply pipe, a desalination circulation water supply pipe isolation valve, a desalination circulation return pipe and a desalination circulation return pipe isolation valve; the inlet pipe of the coagulation sedimentation tank is connected to the raw water intake pump, and ... The outlet pipe of the pool is connected to the inlet pipe of the filter pool, a sedimentation tank outlet pipe valve is installed on the outlet pipe of the coagulation sedimentation tank, and a filter inlet pipe temperature detector is installed on the inlet pipe of the filter pool; the outlet pipe of the filter pool is connected to the inlet pipe of the water storage tank, and the outlet pipe of the water storage tank is divided into three routes, the first route is connected to the production water supply system, the second route is connected to the desalted water making system, and the third route is connected to the desalination circulation 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, and 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 circulation return pipe is connected to the desalination water water production system, and the other end is connected to the circulating water return main pipe. A desalination circulation return pipe isolation valve is installed on the desalination circulation return pipe; the desalination circulation water supply pipe is connected to the circulating water supply main pipe, and a desalination circulation water supply pipe isolation valve is installed on the desalination circulation 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 thermal power station circulating cooling water waste heat recovery and utilization system according to claim 1 is characterized in that: 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 aid dosing system.

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

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

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

6. The thermal power station circulating cooling water waste heat recovery and utilization system according to claim 1 is characterized by: The first outlet pipe of the water storage tank is connected to the production water supply system through a production water supply pump, the second outlet pipe is connected to the desalted water production system through a desalination direct supply water pump, and the third outlet pipe is connected to the desalination circulation water supply pipe through a desalination circulation water supply pump.

7. The thermal power station circulating cooling water waste heat recovery and utilization system according to claim 1 is characterized in that: A return water bypass pipe flow detector is installed on the return water bypass pipe.

8. The thermal power station circulating cooling water waste heat recovery and utilization system according to claim 2 is characterized by: The water return bypass pipe is also connected to the flocculant dosing system.

9. The thermal power station circulating cooling water waste heat recovery and utilization system according to claim 1, characterized in that: Desalination cycle return pipe temperature probe on the desalination cycle return pipe.

10. A working method of a thermal power plant circulating cooling water waste heat recovery system according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) In summer or spring and autumn, when the river water temperature is high, or the circulating cooling water volume of the thermal power station exceeds the desalted water production volume, in order to control the water temperature of the water storage tank, the return water of part of the circulating water of the circulating cooling water system is mixed with the outlet water of the sedimentation tank through the return water bypass pipe to increase the water temperature of the water storage tank; by monitoring the outlet water bypass pipe temperature detector, the return water bypass pipe temperature detector and the filter water inlet pipe temperature detector, the outlet water bypass pipe regulating valve and the return water bypass pipe regulating valve are adjusted to achieve the control of the water temperature on the filter water 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 desalted water supply volume. Close the outlet bypass pipe regulating valve and the return bypass pipe regulating valve, open the sedimentation tank outlet valve, and allow all the sedimentation tank outlet water to enter the filter tank; at the same time, close the cooling tower and the circulating water return main pipe isolation valve, the circulating water pump, and the circulating water supply main pipe isolation valve, open the desalination circulating water supply pump, the desalination circulating water supply pipe isolation valve, and the desalination circulating water return pipe isolation valve, and allow the desalination water in the storage tank to enter the circulating water supply main pipe through the desalination circulating water supply pipe to cool the equipment that needs to be cooled in the power station. The return water enters the desalination water production system through the desalination circulating water return pipe and directly supplies the desalination water production.

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