Cooling water waste heat utilization system and method

Abstract

The present application relates to cooling water waste heat utilization technical field and disclose a kind of cooling water waste heat utilization system and method, including steam assembly, absorption assembly, heat supply assembly and heat storage assembly, steam assembly includes steam turbine and condenser, and the exhaust outlet of steam turbine is connected with condenser;Absorption assembly includes evaporator, generator, absorber and condenser, and the cooling water outlet of condenser is connected with the cooling water inlet of evaporator, and the cooling water outlet of evaporator is connected with the cooling water inlet of condenser, and the exhaust outlet of steam turbine is also connected with generator;Heat supply assembly includes heat network backwater pipe and heat network water supply pipe, and the water outlet of heat network backwater pipe is connected with the heating medium inlet of generator and condenser respectively;Heat storage assembly includes heat storage water tank, and the heating medium outlet of absorber and condenser is connected with the hot water inlet of heat storage water tank respectively, and the hot water outlet of heat storage water tank is connected with heat network water supply pipe, realizes the recycling and heat energy storage of circulating water waste heat.

Description

Technical Field

[0001] This invention belongs to the field of cooling water waste heat utilization technology, specifically relating to a cooling water waste heat utilization system and method. Background Technology

[0002] During the operation of a combined heat and power (CHP) unit, the large amount of latent heat of vaporization carried by the turbine exhaust steam is usually carried away by circulating cooling water through the condenser and finally dissipated into the atmosphere through the cooling tower. This portion of heat is of low grade and enormous quantity, resulting in serious energy waste, also known as cold source loss. At the same time, water evaporation losses in the cooling tower also increase the power plant's water consumption.

[0003] Among existing waste heat recovery technologies, the direct heat exchange method using plate heat exchangers is greatly affected by the seasons, resulting in low recovery efficiency; while heat pump recovery can improve the quality of heat energy, it has problems such as short utilization time and lack of energy storage and peak shaving functions. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of the present invention propose a cooling water waste heat utilization system and method, which can efficiently extract and store the waste heat from low-grade circulating water.

[0005] The waste heat recovery system for cooling water according to an embodiment of the present invention includes a steam assembly, an absorption assembly, a heating assembly, and a heat storage assembly. The steam assembly includes a steam turbine and a condenser. The exhaust outlet of the steam turbine is connected to the condenser, which is used to condense the exhaust steam from the steam turbine using cooling water. The absorption assembly includes an evaporator, a generator, an absorber, and a condenser. The evaporator, absorber, generator, and condenser are connected in sequence to form an absorption heat pump loop. The cooling water outlet of the condenser is connected to the cooling water inlet of the evaporator, and the cooling water outlet of the evaporator is connected to the cooling water inlet of the condenser, so that the cooling water releases heat and cools down in the evaporator before returning to the condenser. The absorber absorbs heat, and the exhaust outlet of the steam turbine is also connected to the generator to provide driving steam to the generator. The absorber and the condenser are used to release heat during the absorption heat pump cycle. The heating assembly includes a heat network return water pipe and a heat network supply water pipe. The outlet of the heat network return water pipe is connected to the heating medium inlet of the generator and the condenser, respectively, to use the heat released by the generator and the condenser to heat the heat network return water. The heat storage assembly includes a hot water storage tank. The heating medium outlets of the absorber and the condenser are connected to the hot water inlet of the hot water storage tank, respectively. The hot water outlet of the hot water storage tank is connected to the heat network supply water pipe to release the stored heat when needed.

[0006] The cooling water waste heat utilization system of this invention extracts and heats the low-grade heat energy in the condenser outlet cooling water through the setting of an absorption heat pump circulation loop, and then uses it to heat the return water of the heating network. This effectively reduces the unit's cold source loss and realizes the recovery and utilization of circulating water waste heat. By storing excess heat in a hot water storage tank, thermal energy storage is achieved, which enables flexible adjustment of heating output when the grid load fluctuates, thereby improving the unit's ability to participate in grid peak shaving.

[0007] In some embodiments, the steam assembly further includes a generator and a cooling tower, the steam turbine being connected to the generator to drive the generator to generate electricity, the cooling water outlet of the condenser being connected to the inlet of the cooling tower, and the outlet of the cooling tower being connected to the cooling water inlet of the condenser, so as to cool and recycle a portion of the cooling water that does not enter the evaporator.

[0008] In some embodiments, the absorption assembly further includes a solution pump and a throttling device. The solution outlet of the absorber is connected to the solution inlet of the generator via the solution pump to send the refrigerant and absorbent mixture in the absorber into the generator. The refrigerant outlet of the condenser is connected to the refrigerant inlet of the evaporator via the throttling device to throttle and depressurize the condensed refrigerant and send it back to the evaporator for heat absorption and vaporization.

[0009] In some embodiments, the heating assembly further includes a heat network heater and a heat network circulation pump. The heat network circulation pump is disposed on the heat network return water pipe to drive the flow of heat network return water. The heating medium outlets of the absorber and the condenser are both connected to the inlet of the heat network heater. The outlet of the heat network heater is connected to the heat network supply water pipe to further heat the heat network return water before supplying heat to the outside.

[0010] In some embodiments, the heat storage assembly further includes a first heating network water supply electric valve and a second heating network water supply electric valve. The heating medium outlets of the absorber and the condenser are connected to the heating network heater via the first heating network water supply electric valve and to the hot water inlet of the hot water storage tank via the second heating network water supply electric valve.

[0011] In some embodiments, the heat storage assembly further includes a first heating network return water electric valve and a second heating network return water electric valve. The cold water outlet of the hot water storage tank is connected to the heating network return water pipe via the first heating network return water electric valve to send the cold water at the bottom of the hot water storage tank back to the heating network return water side for circulation heating. The cold water outlet of the hot water storage tank is connected to an external drainage pipe via the second heating network return water electric valve to discharge the water accumulated in the tank when needed.

[0012] In some embodiments, the cooling water waste heat utilization system further includes a steam supply assembly, which includes a heat exchanger, a deaerator, an electrode boiler feed pump, an electrode boiler, and an electric heater. The hot water outlet of the hot water storage tank is connected to the heat source medium inlet of the heat exchanger to send the stored hot water into the heat exchanger for heat release. The heat source medium outlet of the heat exchanger is connected to the cold water inlet of the hot water storage tank so that the released cold water returns to the bottom of the hot water storage tank. The heated medium outlet of the heat exchanger is sequentially connected to the deaerator, the electrode boiler feed pump, the electrode boiler, and the electric heater to sequentially deaerate the heated demineralized water, generate saturated steam, heat it into superheated steam, and finally send it into the industrial steam supply pipe.

[0013] In some embodiments, the electrode boiler includes an inner cylinder and an outer cylinder, the inner cylinder being disposed inside the outer cylinder, and an electrode boiler internal circulation pump being disposed between the inner cylinder and the outer cylinder. The electrode boiler internal circulation pump is used to send deoxygenated water from the outer cylinder into the inner cylinder to contact the electrode rods and generate saturated steam.

[0014] In some embodiments, the steam supply assembly further includes a demineralized water pipe, the outlet of which is connected to the inlet of the heated medium of the heat exchanger to provide ambient temperature demineralized water.

[0015] The method for utilizing waste heat from cooling water according to embodiments of the present invention, using any of the above-described waste heat utilization systems for cooling water, includes the following steps:

[0016] Cooling water circulation steps: After absorbing the heat of the turbine exhaust steam in the condenser, part of the cooling water enters the evaporator to release heat and cool down, and then returns to the condenser to absorb heat again. Heat pump drive steps: The exhaust steam from the steam turbine enters the generator as driving steam, which enables the absorption heat pump circulation loop to run. The absorber and condenser release heat during the circulation process. Heating process of the heating network: The return water from the heating network enters the absorber and condenser respectively, and its temperature rises after absorbing the heat released by the absorber and condenser. Thermal storage and heating process: After the heating network return water is heated, part or all of it is sent to the hot water storage tank for storage, or the stored hot water is released from the hot water storage tank when needed, and used together with the heated heating network return water to provide heat to the outside. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention. Figure 1 .

[0018] Figure 2 This is a schematic diagram of the structure of the present invention. Figure 2 .

[0019] Figure 3 This is a schematic diagram of the structure of the present invention. Figure 3 .

[0020] Figure label: 1. Steam turbine; 2. Condenser; 3. Evaporator; 4. Generator; 5. Absorber; 6. Condenser; 7. Heat network return water pipe; 8. Heat network supply water pipe; 9. Hot water storage tank; 10. Generator; 11. Cooling tower; 12. Solution pump; 13. Throttling device; 14. Heat network heater; 15. Heat network circulation pump; 16. First heat network supply water electric valve; 17. Second heat network supply water electric valve; 18. First heat network return water electric valve; 19. Second heat network return water electric valve; 20. Heat exchanger; 21. Deaerator; 22. Electrode boiler feed water pump; 23. Electrode boiler; 231. Inner cylinder; 232. Outer cylinder; 233. Electrode boiler internal circulation pump; 24. Electric heater; 25. Industrial steam supply pipe; 26. Demineralized water pipe. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0022] like Figures 1-3 As shown, the waste heat recovery system for cooling water in this embodiment of the invention includes a steam assembly, an absorption assembly, a heating assembly, and a heat storage assembly. The steam assembly includes a steam turbine 1 and a condenser 2. The exhaust outlet of the steam turbine 1 is connected to the condenser 2, which is used to condense the exhaust steam from the steam turbine 1 using cooling water. The absorption assembly includes an evaporator 3, a generator 4, an absorber 5, and a condenser 6. The evaporator 3, absorber 5, generator 4, and condenser 6 are connected in sequence to form an absorption heat pump loop. The cooling water outlet of the condenser 2 is connected to the cooling water inlet of the evaporator 3, and the cooling water outlet of the evaporator 3 is connected to the cooling water inlet of the condenser 2, so that the cooling water releases heat and cools down in the evaporator 3. After being heated, the steam returns to the condenser 2 to absorb heat. The exhaust outlet of the turbine 1 is also connected to the generator 4 to provide driving steam to the generator 4. The absorber 5 and condenser 6 are used to release heat during the absorption heat pump cycle. The heating assembly includes a heat network return water pipe 7 and a heat network supply water pipe 8. The outlet of the heat network return water pipe 7 is connected to the heating medium inlet of the generator 4 and the condenser 6, respectively, to use the heat released by the generator 4 and the condenser 6 to heat the heat network return water. The heat storage assembly includes a hot water storage tank 9. The heating medium outlets of the absorber 5 and the condenser 6 are connected to the hot water inlet of the hot water storage tank 9, respectively. The hot water outlet of the hot water storage tank 9 is connected to the heat network supply water pipe 8 to release the stored heat when needed.

[0023] The cooling water waste heat utilization system of this invention extracts and heats the low-grade heat energy in the condenser outlet cooling water through the setting of an absorption heat pump circulation loop, and then uses it to heat the return water of the heating network. This effectively reduces the unit's cold source loss and realizes the recovery and utilization of circulating water waste heat. By storing excess heat in a hot water storage tank, thermal energy storage is achieved, which enables flexible adjustment of heating output when the grid load fluctuates, thereby improving the unit's ability to participate in grid peak shaving.

[0024] Specifically, the steam discharged from turbine 1 enters condenser 2, where it exchanges heat with cooling water and condenses to maintain turbine back pressure. The cooling water absorbs heat from the exhaust steam in condenser 2, increasing in temperature. Part of the cooling water enters evaporator 3 in the absorption heat pump loop, acting as a low-temperature heat source to release heat to the refrigerant. After its temperature decreases, the cooling water returns to condenser 2 to absorb heat again, forming a cooling water circulation. A portion of the exhaust steam from turbine 1 enters generator 4, serving as the driving steam for the absorption heat pump. This heats the refrigerant-absorbent solution in generator 4, causing the lower-boiling-point refrigerant to vaporize into a high-pressure gaseous refrigerant, which then enters condenser 6. The remaining absorbent solution returns to absorber 5. The high-pressure gaseous refrigerant releases heat to the heat network return water in condenser 6, condensing into a high-pressure liquid refrigerant. After being depressurized by throttling device 13, it becomes a low-pressure liquid refrigerant and enters evaporator 3. The low-pressure liquid refrigerant absorbs heat from the cooling water in evaporator 3, vaporizing into a low-pressure gaseous refrigerant, which then enters absorber 5. In absorber 5, low-pressure gaseous refrigerant is absorbed by absorbent from generator 4. This process is exothermic. The refrigerant mixes with absorbent again to form a refrigerant-absorbent solution, which is then pressurized by solution pump 12 and sent back to generator 4, completing the absorption heat pump cycle. Absorber 5 and condenser 6 continuously release heat during the cycle. Heat network return water, driven by heat network circulation pump 15, enters absorber 5 and condenser 6 sequentially via heat network return water pipe 7, absorbing the heat released by absorber 5 and condenser 6 as a cooling medium, and its temperature gradually increases. The heated heat network return water is partially or entirely stored in hot water storage tank 9, or, when needed, the stored hot water is released from hot water storage tank 9 and further heated by heat network heater 14 together with the heated heat network return water before being supplied to the outside through heat network supply water pipe 8.

[0025] In some embodiments, the steam assembly further includes a generator 10 and a cooling tower 11. The steam turbine 1 is connected to the generator 10 to drive the generator 10 to generate electricity. The cooling water outlet of the condenser 2 is connected to the inlet of the cooling tower 11, and the outlet of the cooling tower 11 is connected to the cooling water inlet of the condenser 2, so as to cool down and recycle a portion of the cooling water that does not enter the evaporator 3.

[0026] The waste heat recovery system for cooling water in this embodiment of the invention converts the mechanical energy of a steam turbine into electrical energy through a generator, realizing the conversion and utilization of thermal energy into electrical energy. Cooling water that does not enter the evaporator is cooled by a cooling tower and then recycled, ensuring that the condenser maintains good condensation efficiency. By diverting the cooling water to the absorption heat pump and the cooling tower, both the amount of waste heat recovered and the safe and stable operation of the system are guaranteed.

[0027] Specifically, the steam turbine 1 rotates under the drive of steam, which in turn drives the generator 10 connected to it to generate electricity, converting thermal energy into electrical energy and feeding it into the power grid. The steam after performing work enters the condenser 2 from the exhaust outlet of the steam turbine 1, where it exchanges heat with cooling water and condenses. The cooling water absorbs heat from the exhaust steam in the condenser 2, causing its temperature to rise. It then splits into two paths: one path enters the evaporator 3 of the absorption heat pump loop, where it acts as a low-temperature heat source, releasing heat to the refrigerant, and then returns to the condenser 2 to absorb heat again; the other path enters the cooling tower 11, where it is further cooled through air convection and evaporative cooling, and then returns to the condenser 2 to absorb heat again.

[0028] In some embodiments, the absorption assembly further includes a solution pump 12 and a throttling device 13. The solution outlet of the absorber 5 is connected to the solution inlet of the generator 4 via the solution pump 12 to send the refrigerant and absorbent mixture in the absorber 5 into the generator 4. The refrigerant outlet of the condenser 6 is connected to the refrigerant inlet of the evaporator 3 via the throttling device 13 to throttle and depressurize the condensed refrigerant and send it back to the evaporator 3 for heat absorption and vaporization.

[0029] The waste heat recovery system for cooling water in this embodiment of the invention uses a solution pump to pressurize the refrigerant and absorbent mixture in the absorber and then send it to the generator, overcoming the pressure difference barrier in the system circulation and ensuring the continuous and stable operation of the absorption heat pump. A throttling device reduces the pressure of the condensed high-pressure liquid refrigerant, allowing it to absorb heat and vaporize at a low temperature in the evaporator, thus maintaining the refrigerant's heat absorption capacity in the evaporator.

[0030] Specifically, in absorber 5, low-pressure gaseous refrigerant is absorbed by the absorbent, forming a mixed solution of refrigerant and absorbent. Solution pump 12 draws this solution from the solution outlet of absorber 5, pressurizes it, and sends it to generator 4. In generator 4, exhaust steam from turbine 1 heats the solution, causing the refrigerant with a lower boiling point to vaporize and separate, becoming high-pressure gaseous refrigerant that enters condenser 6. The remaining absorbent solution returns to absorber 5. After releasing heat to the heat network return water in condenser 6, the high-pressure gaseous refrigerant condenses into high-pressure liquid refrigerant. The high-pressure liquid refrigerant flows through throttling device 13, where it is throttled and depressurized, becoming low-pressure liquid refrigerant, and enters evaporator 3. In evaporator 3, the low-pressure liquid refrigerant absorbs heat from the cooling water of condenser 2, vaporizes into low-pressure gaseous refrigerant, and re-enters absorber 5 to be absorbed by the absorbent, completing the entire cycle.

[0031] In some embodiments, the heating assembly further includes a heat network heater 14 and a heat network circulation pump 15. The heat network circulation pump 15 is disposed on the heat network return water pipe 7 to drive the flow of heat network return water. The heating medium outlets of the absorber 5 and the condenser 6 are both connected to the inlet of the heat network heater 14. The outlet of the heat network heater 14 is connected to the heat network supply water pipe 8 to further heat the heat network return water before supplying heat to the outside.

[0032] The cooling water waste heat utilization system of this invention provides stable power for the circulation of heat network water through a heat network circulation pump, ensuring that the heat network return water can continuously flow through the absorber and condenser to absorb heat, thus guaranteeing the reliable operation of the heating system. A heat network heater further heats the heat network return water after it has been heated by the absorption heat pump, allowing the supply water temperature to be flexibly adjusted to the heating demand value. This solves the problem of insufficient temperature rise that may occur when the absorption heat pump is used alone, ensuring the quality of heating.

[0033] Specifically, the heating network circulation pump 15 provides power for the entire heating network water circulation, driving the low-temperature heating network return water from the return water side to the absorber 5 and condenser 6. Under the action of the heating network circulation pump 15, the heating network return water flows sequentially through the absorber 5 and condenser 6, absorbing the heat released by the absorber 5 and condenser 6 during the absorption heat pump cycle, and its temperature gradually increases. After being heated by the absorber 5 and condenser 6, the heating network return water flows out from the heating medium outlet of the absorber 5 and condenser 6 and enters the heating network heater 14. In the heating network heater 14, the heating network return water is further heated to the supply water temperature that meets the heating requirements, and then sent to the heating network supply water side for external heating through the heating network supply water pipe 8.

[0034] In some embodiments, the heat storage assembly further includes a first heating network water supply electric valve 16 and a second heating network water supply electric valve 17. The heating medium outlets of the absorber 5 and the condenser 6 are connected to the heating network heater 14 via the first heating network water supply electric valve 16 and to the hot water inlet of the hot water storage tank 9 via the second heating network water supply electric valve 17.

[0035] The cooling water waste heat utilization system of this invention, through the coordinated control of the first and second heating network water supply electric valves, achieves flexible allocation of heated heating network return water between direct heating and heat storage, allowing the system to dynamically adjust its operating mode according to changes in unit load and heat demand. When the unit load is low and the heating demand is small, excess heat is stored in the hot water storage tank by opening the second heating network water supply electric valve, avoiding heat waste; when the load is high or the heat demand increases, the stored heat is released to meet the heating demand, achieving an organic combination of waste heat utilization and energy storage peak shaving.

[0036] Specifically, after being heated by the absorber 5 and the condenser 6, the return water from the heating medium outlet flows out and faces two paths: one path flows through the first heating network water supply electric valve 16 to the heating network heater 14, where it is further heated and then supplied to the outside; the other path flows through the second heating network water supply electric valve 17 to the hot water inlet of the hot water storage tank 9, where the hot water is stored in the upper part of the hot water storage tank 9.

[0037] By adjusting the opening degree of the first heating network water supply electric valve 16 and the second heating network water supply electric valve 17, three operating modes can be achieved: Heat storage mode: The second heating network water supply electric valve 17 is partially opened, allowing a portion of the heated heating network return water to flow into the heat storage tank 9 to store heat; at the same time, the first heating network water supply electric valve 16 is partially opened, allowing the remaining portion to flow directly into the heating network heater 14 for further heating and then supplying heat to the outside.

[0038] Static mode: Fully open the first heating network water supply electric valve 16 and fully close the second heating network water supply electric valve 17, so that all the heated heating network return water flows directly into the heating network heater 14 for external heating, and the hot water storage tank 9 does not participate in the operation.

[0039] Heat release mode: When it is necessary to release the heat in the hot water storage tank 9, the first heating network water supply electric valve 16 can be closed or partially closed, and the stored hot water can be sent to the heating network heater 14 or the heating pipeline through the hot water outlet of the hot water storage tank 9.

[0040] In some embodiments, the heat storage assembly further includes a first heating network return water electric valve 18 and a second heating network return water electric valve 19. The cold water outlet of the hot water storage tank 9 is connected to the heating network return water pipe 7 via the first heating network return water electric valve 18 to send the cold water at the bottom of the hot water storage tank 9 back to the heating network return water side for circulation heating. The cold water outlet of the hot water storage tank 9 is connected to an external drainage pipe via the second heating network return water electric valve 19 to discharge the water accumulated in the tank when needed.

[0041] The cooling water waste heat recovery system of this invention uses a first heating network return water electric valve to return cold water from the bottom of the hot water storage tank to the heating network return water pipe for recirculation and heating, thus realizing the reuse of cold water and avoiding heat loss with the discharge of cold water. A second heating network return water electric valve connects to the external drainage pipeline, facilitating drainage operations during system maintenance, cleaning, or emergencies. The two return water electric valves, in conjunction with the two supply water electric valves, constitute a complete control system for the inlet and outlet water pipelines of the heat storage tank, enabling the hot water storage tank to flexibly switch between heat storage, static, and heat release modes and maintain long-term stable operation.

[0042] Specifically, the hot water storage tank 9 adopts a natural stratified design, with the upper part being the hot water side and the lower part the cold water side. When the hot water storage tank 9 is in heat release mode, the hot water in the upper part is extracted and sent to the heating network heater 14 or heat exchanger 20 for use, while the cold water in the lower part gradually accumulates. The first heating network return water electric valve 18 connects the cold water outlet of the hot water storage tank 9 to the heating network return water pipe 7. When the first heating network return water electric valve 18 is opened, the cold water at the bottom of the hot water storage tank 9 is sent back to the heating network return water pipe 7, mixes with the low-temperature return water from the heating network return water side, and re-enters the absorber 5 and condenser 6 for heating, realizing the recycling of cold water. This avoids heat loss and maintains the water balance of the hot water storage tank 9. The second heating network return water electric valve 19 connects the cold water outlet of the hot water storage tank 9 to the external drainage pipe. When the system needs maintenance, cleaning of the hot water storage tank 9, or when the water quality in the tank deteriorates and needs to be replaced, the second heating network return water electric valve 19 can be opened to discharge the accumulated water in the tank to the external drainage system.

[0043] In heat storage mode, the first heat network return water electric valve 18 is usually kept closed, allowing cold water to settle naturally in the tank and maintain the stratification effect. In heat release mode, the first heat network return water electric valve 18 is opened in a timely manner according to the water level in the tank to send the cold water back for circulation heating. The second heat network return water electric valve 19 is only opened for drainage operation under special working conditions.

[0044] In some embodiments, the cooling water waste heat utilization system further includes a steam supply assembly, which includes a heat exchanger 20, a deaerator 21, an electrode boiler feed pump 22, an electrode boiler 23, and an electric heater 24. The hot water outlet of the hot water storage tank 9 is connected to the heat source medium inlet of the heat exchanger 20 to send the stored hot water into the heat exchanger 20 to release heat. The heat source medium outlet of the heat exchanger 20 is connected to the cold water inlet of the hot water storage tank 9 so that the released cold water returns to the bottom of the hot water storage tank 9. The heated medium outlet of the heat exchanger 20 is sequentially connected to the deaerator 21, the electrode boiler feed pump 22, the electrode boiler 23, and the electric heater 24 to sequentially deaerate the heated demineralized water, generate saturated steam, heat it into superheated steam, and finally send it into the industrial steam supply pipe 25.

[0045] The waste heat recovery system for cooling water in this invention transfers the heat energy stored in the hot water storage tank to the demineralized water via a heat exchanger, enabling the waste heat of the circulating water to be extended to the industrial steam supply field. A deaerator thermally deoxygenates the preheated demineralized water. The deoxygenated water is pressurized and fed into the electrode boiler via an electrode boiler feed pump, ensuring stable boiler inlet water pressure and guaranteeing the continuity and reliability of steam generation. The electrode boiler uses electricity to heat the deoxygenated water to generate saturated steam, allowing the system to maintain a stable industrial steam supply capacity even during peak shaving and reduced heating steam extraction. An electric heater further heats the saturated steam into superheated steam, eliminating condensation losses during long-distance transportation and ensuring the quality of steam for industrial users.

[0046] Specifically, when the system is in heat release mode, the hot water at the top of the hot water storage tank 9 flows out from the hot water outlet and splits into two paths: one path enters the heating network heater 14 for heating, and the other path enters the heat source medium inlet of the heat exchanger 20 to heat the demineralized water on the other side of the heat exchanger 20. In the heat exchanger 20, the hot water from the hot water storage tank 9 exchanges heat with the ambient temperature demineralized water from the plant area. After releasing heat, the hot water's temperature decreases, and it flows out from the heat source medium outlet of the heat exchanger 20, returning to the cold water inlet at the bottom of the hot water storage tank 9 to re-enter the circulation on the cold water side. The ambient temperature demineralized water absorbs heat and its temperature rises, flowing out from the heated medium outlet of the heat exchanger 20. The heated demineralized water then enters the deaerator 21. In the deaerator 21, the extracted steam from the turbine 1 is used as heating steam to thermally deoxygenate the demineralized water, removing dissolved oxygen and preventing corrosion of subsequent equipment and pipelines. The deoxygenated water is called deoxygenated water. Deoxygenated water is pressurized by electrode boiler feed pump 22 and then sent to electrode boiler 23. In electrode boiler 23, the deoxygenated water comes into contact with the electrode rods and is directly heated by electrical energy to generate saturated steam. The saturated steam flows out of electrode boiler 23 and enters electric heater 24. In electric heater 24, the saturated steam is further heated to become superheated steam to eliminate condensation losses during transportation, and is finally delivered to industrial users through industrial steam supply pipe 25.

[0047] In some embodiments, the electrode boiler 23 includes an inner cylinder 231 and an outer cylinder 232. The inner cylinder 231 is disposed inside the outer cylinder 232. An electrode boiler internal circulation pump 233 is disposed between the inner cylinder 231 and the outer cylinder 232. The electrode boiler internal circulation pump 233 is used to send deoxygenated water in the outer cylinder 232 into the inner cylinder 231 to contact the electrode rod and generate saturated steam.

[0048] The waste heat recovery system for cooling water in this embodiment of the invention separates the heating core from the water storage buffer through a double-layer structure design of an inner and outer cylinder. Forced water circulation via an internal circulation pump in the electrode boiler ensures that deoxygenated water from the outer cylinder is continuously supplied to the inner cylinder to contact the electrode rods, guaranteeing the continuity and stability of steam generation.

[0049] Specifically, when the electrode boiler is running, the internal circulation pump 233 starts, drawing deoxygenated water from the outer cylinder 232 and sending it into the inner cylinder 231. Upon entering the inner cylinder 231, the deoxygenated water comes into direct contact with the electrode rods and is rapidly heated under the influence of electric current, causing some of the water to vaporize and produce saturated steam. The saturated steam is then discharged from the top of the inner cylinder 231 and enters the electric heater 24 for further heating. Unvaporized hot water and newly added deoxygenated water overflow from the inner cylinder 231 or flow back to the outer cylinder 232, mixing with the water in the outer cylinder 232, and then are again sent back into the inner cylinder 231 by the internal circulation pump 233 for heating, forming a continuous cycle.

[0050] In some embodiments, the steam supply assembly further includes a demineralized water pipe 26, the outlet of which is connected to the inlet of the heated medium of the heat exchanger 20 to provide ambient temperature demineralized water.

[0051] The cooling water waste heat recovery system of this invention provides a stable source of demineralized water at room temperature through a demineralized water pipe, ensuring the continuous operation of the steam supply components.

[0052] Specifically, one end of the demineralized water pipe 26 is connected to the plant's demineralized water supply system, and the other end is connected to the inlet of the heated medium in the heat exchanger 20. The ambient temperature demineralized water supplied by the plant is continuously supplied through the demineralized water pipe 26 and enters the heat exchanger 20. In the heat exchanger 20, the ambient temperature demineralized water from the demineralized water pipe 26 exchanges heat with the hot water from the hot water storage tank 9. After absorbing heat from the hot water, the ambient temperature demineralized water's temperature rises and flows out from the outlet of the heated medium in the heat exchanger 20, entering subsequent equipment such as the deaerator 21 and the electrode boiler 23 for further processing.

[0053] The method for utilizing waste heat from cooling water according to embodiments of the present invention, using any of the above-described waste heat utilization systems for cooling water, includes the following steps: Cooling water circulation steps: After absorbing the heat of the turbine exhaust steam in the condenser, part of the cooling water enters the evaporator to release heat and cool down, and then returns to the condenser to absorb heat again. Heat pump drive steps: The exhaust steam from the steam turbine enters the generator as driving steam, which enables the absorption heat pump circulation loop to run. The absorber and condenser release heat during the circulation process. Heating process of the heating network: The return water from the heating network enters the absorber and condenser respectively, and its temperature rises after absorbing the heat released by the absorber and condenser. Thermal storage and heating process: After the heating network return water is heated, part or all of it is sent to the hot water storage tank for storage, or the stored hot water is released from the hot water storage tank when needed, and used together with the heated heating network return water to provide heat to the outside.

[0054] The waste heat utilization method for cooling water in this invention, through a cooling water circulation step, introduces the condensation heat of turbine exhaust steam into an absorption heat pump system via cooling water, realizing the recovery and utilization of cold source losses that were originally discharged through the cooling tower, significantly reducing energy waste. Through a heat pump drive step, a portion of the turbine exhaust steam is used as driving energy to propel the absorption heat pump in circulation, upgrading the low-grade heat energy in the cooling water into high-grade heat energy usable for heating. Through a heating network step, the heat released by the absorber and condenser is directly transferred to the heating network return water, completing the conversion of waste heat into heating. Through a heat storage heating step, heat energy is stored, storing surplus heat during low-load periods and releasing it during high-load or peak heat demand periods, effectively solving the problem of time mismatch between waste heat utilization and heat demand, and significantly improving the unit's energy storage and peak-shaving capacity.

[0055] Specifically, Cooling water circulation steps: The exhaust steam from the steam turbine condenses in the condenser, and the released heat is absorbed by the cooling water, causing the cooling water temperature to rise. Some of the high-temperature cooling water enters the evaporator, where it acts as a low-temperature heat source for the absorption heat pump, releasing heat to the refrigerant. After its own temperature decreases, it returns to the condenser to absorb heat again.

[0056] Heat pump drive steps: Exhaust steam from the turbine enters the generator, where it acts as driving steam to heat the refrigerant and absorbent mixture, causing the refrigerant to vaporize and separate. The absorption heat pump cycle continues to operate under the action of the driving steam, with the absorber and condenser continuously releasing heat during the cycle.

[0057] Heating process of the heating network: The return water of the heating network flows through the absorber and condenser in sequence, and absorbs the heat released by both as a cooling medium, and its own temperature gradually increases.

[0058] Thermal storage heating process: After heating, the return water from the heating network can be used to supply heat directly to the outside, or part or all of it can be stored in a hot water storage tank, depending on the system's operational needs. During peak heat demand or when unit load fluctuates, the stored hot water in the hot water storage tank is released to supply heat to the outside together with the real-time heated return water from the heating network.

[0059] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0061] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0062] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0063] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0064] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A cooling water waste heat recovery system, characterized in that, include: A steam assembly, comprising a steam turbine and a condenser, wherein the exhaust outlet of the steam turbine is connected to the condenser, and the condenser is used to condense the exhaust steam of the steam turbine using cooling water; An absorption assembly, comprising an evaporator, a generator, an absorber, and a condenser, is sequentially connected to form an absorption heat pump loop. The cooling water outlet of the condenser is connected to the cooling water inlet of the evaporator, and the cooling water outlet of the evaporator is also connected to the cooling water inlet of the condenser, so that the cooling water releases heat and cools down in the evaporator before returning to the condenser to absorb heat. The exhaust outlet of the steam turbine is also connected to the generator to provide driving steam to the generator. The absorber and the condenser are used to release heat during the absorption heat pump cycle. A heating assembly, comprising a heat network return water pipe and a heat network supply water pipe, wherein the outlet of the heat network return water pipe is connected to the heating medium inlet of the generator and the condenser respectively, so as to use the heat released by the generator and the condenser to heat the heat network return water; A heat storage assembly includes a hot water storage tank. The heating medium outlets of the absorber and the condenser are respectively connected to the hot water inlet of the hot water storage tank. The hot water outlet of the hot water storage tank is connected to the heating network water supply pipe to release the stored heat when needed.

2. The cooling water waste heat recovery system according to claim 1, characterized in that, The steam assembly also includes a generator and a cooling tower. The steam turbine is connected to the generator to drive the generator to generate electricity. The cooling water outlet of the condenser is connected to the inlet of the cooling tower, and the outlet of the cooling tower is connected to the cooling water inlet of the condenser, so as to cool and recycle some of the cooling water that does not enter the evaporator.

3. The cooling water waste heat recovery system according to claim 1, characterized in that, The absorption assembly also includes a solution pump and a throttling device. The solution outlet of the absorber is connected to the solution inlet of the generator via the solution pump to send the refrigerant and absorbent mixture in the absorber into the generator. The refrigerant outlet of the condenser is connected to the refrigerant inlet of the evaporator via the throttling device to throttle and depressurize the condensed refrigerant and send it back to the evaporator to absorb heat and vaporize.

4. The cooling water waste heat recovery system according to claim 1, characterized in that, The heating assembly also includes a heating network heater and a heating network circulation pump. The heating network circulation pump is installed on the heating network return water pipe to drive the flow of heating network return water. The heating medium outlets of the absorber and the condenser are both connected to the inlet of the heating network heater. The outlet of the heating network heater is connected to the heating network supply water pipe to further heat the heating network return water before supplying heat to the outside.

5. The cooling water waste heat recovery system according to claim 4, characterized in that, The heat storage assembly also includes a first heating network water supply electric valve and a second heating network water supply electric valve. The heating medium outlets of the absorber and the condenser are connected to the heating network heater via the first heating network water supply electric valve and to the hot water inlet of the hot water storage tank via the second heating network water supply electric valve.

6. The cooling water waste heat recovery system according to claim 5, characterized in that, The heat storage component also includes a first heating network return water electric valve and a second heating network return water electric valve. The cold water outlet of the hot water storage tank is connected to the heating network return water pipe via the first heating network return water electric valve to send the cold water at the bottom of the hot water storage tank back to the heating network return water side for circulation and heating. The cold water outlet of the hot water storage tank is connected to an external drainage pipe via the second heating network return water electric valve to discharge the water accumulated in the tank when needed.

7. The cooling water waste heat recovery system according to claim 1, characterized in that, It also includes a steam supply assembly, which includes a heat exchanger, a deaerator, an electrode boiler feed pump, an electrode boiler, and an electric heater. The hot water outlet of the hot water storage tank is connected to the heat source medium inlet of the heat exchanger to send the stored hot water into the heat exchanger for heat release. The heat source medium outlet of the heat exchanger is connected to the cold water inlet of the hot water storage tank so that the released cold water returns to the bottom of the hot water storage tank. The heated medium outlet of the heat exchanger is connected in sequence to the deaerator, the electrode boiler feed pump, the electrode boiler, and the electric heater to sequentially deaerate the heated demineralized water, generate saturated steam, heat it into superheated steam, and finally send it into the industrial steam supply pipe.

8. The cooling water waste heat recovery system according to claim 7, characterized in that, The electrode boiler includes an inner cylinder and an outer cylinder. The inner cylinder is located inside the outer cylinder. An internal circulation pump for the electrode boiler is provided between the inner cylinder and the outer cylinder. The internal circulation pump is used to send deoxygenated water from the outer cylinder into the inner cylinder to contact the electrode rods and generate saturated steam.

9. The cooling water waste heat recovery system according to claim 7, characterized in that, The steam supply assembly also includes a demineralized water pipe, the outlet of which is connected to the inlet of the heated medium of the heat exchanger to provide demineralized water at room temperature.

10. A method for utilizing waste heat from cooling water, comprising a waste heat utilization system for cooling water according to any one of claims 1-9, characterized in that, Includes the following steps: Cooling water circulation steps: After absorbing the heat of the turbine exhaust steam in the condenser, part of the cooling water enters the evaporator to release heat and cool down, and then returns to the condenser to absorb heat again. Heat pump drive steps: The exhaust steam from the steam turbine enters the generator as driving steam, which enables the absorption heat pump circulation loop to run. The absorber and condenser release heat during the circulation process. Heating process of the heating network: The return water from the heating network enters the absorber and condenser respectively, and its temperature rises after absorbing the heat released by the absorber and condenser. Thermal storage and heating process: The heated return water from the heating network is sent to a hot water storage tank for storage. When needed, the stored hot water is released from the hot water storage tank and used together with the heated return water from the heating network to provide heat to the outside.

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