Energy storage peak regulation system and method coupling waste heat recovery and water body heat storage

Abstract

The embodiment of the invention provides an energy storage peak regulation system and method coupling waste heat recovery and water body heat storage. The system comprises a thermal power generation subsystem, a circulating water waste heat utilization subsystem, a water body heat storage subsystem and a heating subsystem. By recycling waste heat of circulating water, the heat efficiency of the unit can be improved under the same combined heat and power generation capacity, the coal consumption rate is reduced, and energy-saving and carbon-reducing transformation is assisted to be achieved. After the water body heat storage technology is coupled, the system can participate in peak regulation and peak service all the year round, and flexible transformation is assisted to be achieved; the diversified heat supply modes of steam extraction heat supply, circulating water waste heat recovery heat supply and heat storage water body heat supply assist in achieving heat supply transformation. The circulating water waste heat utilization technology and the water heat storage technology are deeply coupled with an existing combined heat and power generation unit, and energy-saving and carbon-reducing transformation, flexible transformation and heat supply transformation of the combined heat and power generation unit can be achieved at the same time.

Description

Technical Field

[0001] The embodiments of the present disclosure belong to the technical field of thermal storage and peak regulation, and specifically relate to an energy storage and peak regulation system and method that couples waste heat recovery and water body thermal storage. Background Art

[0002] In the new power system, the contradiction between electricity and heat faced by the traditional cogeneration unit's "heat-based electricity" operation mode is becoming increasingly prominent. If the thermal power unit exerts its maximum heating capacity, the power output cannot be adjusted. If the power output is reduced to meet the peak demand of electricity, the heating capacity will decrease accordingly. This operation mode in which thermal and electric outputs are coupled and constrained makes it difficult for cogeneration units to fully adapt to the new power system, facing the dilemma of not being able to achieve both peak-shaving benefits and heating guarantees. This is also the significance of the country's vigorous promotion of the "three reforms and linkages". Energy saving and carbon reduction, flexibility and heating cannot be neglected. In order to achieve a comprehensive balance of the three, it is urgent to develop new transformation technologies suitable for thermal power units.

[0003] At present, there are two main directions for the technical transformation of thermal power units: the boiler and steam turbine body side and external heat storage technology. The transformation technologies on the boiler and steam turbine body side mainly include low-load stable combustion technology, high back pressure operation technology, low-pressure cylinder zero output technology, etc. The minimum output load of most units is reduced to 30-40% of the rated load, but it has gradually failed to meet the power grid's demand for peak-shaving and frequency-regulating power sources. Although it can alleviate the contradiction between adjustment flexibility and heating to a certain extent, it brings about the problem of increased coal consumption rate and cannot meet the energy conservation and carbon reduction needs at the same time. External heat storage technology mainly includes electrode boiler + hot water storage tank, molten salt heat storage and solid heat storage technologies. By storing electricity or steam in the form of heat during the peak-shaving period, the effect of peak shaving and valley filling can be achieved. However, the electrode boiler converts high-grade electricity into low-grade heat, and the quality loss of thermal energy is large. Molten salt or solid thermal storage technology also converts high-grade electricity or higher-grade steam into heat. The heat storage range is usually between 200 and 500°C, which does not match the temperature required for heating. It can usually be combined with industrial steam supply needs. These technologies are still in the promotion stage. Heat pump technology based on circulating water waste heat recovery can recover part of the low-grade waste heat of circulating water for heating, reduce steam extraction for heating, and achieve energy saving and carbon reduction. However, current heat pump equipment can only be used in the heating season, and the use time throughout the year is limited, and it has not yet been combined with the peak-shaving and frequency-regulating technology of thermal power units.

[0004] In summary, the above technologies can only achieve one or two of the energy-saving and carbon-reduction transformation, flexibility transformation and heating transformation of thermal power units, and it is difficult to take both into account at the same time. Therefore, how to achieve the "three-in-one linkage" of energy-saving and carbon-reduction, flexibility and heating for cogeneration units is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The present disclosure aims to solve at least one of the technical problems existing in the prior art, and provides an energy storage peak-shaving system and method that couples waste heat recovery and water body heat storage. In the non-heating season, it is possible to perform heat storage peak-shaving by recovering the waste heat of circulating water, and to release heat by heating the feed water for peak supply. In the heating season, it is also possible to perform heat storage peak-shaving by recovering the waste heat of circulating water, and to release heat by heating the return water of the heating network for peak supply. The energy storage peak-shaving system and operation method provided by the present invention enable the cogeneration unit to recover the waste heat of circulating water for heat storage and to increase the peak-shaving depth during peak-shaving throughout the year. The stored heat can assist the unit in reaching its peak and alleviate the thermal-electric contradiction of the thermal power unit.

[0006] To achieve the above objectives, the present invention adopts the following technical solutions:

[0007] A energy storage peak-shaving system coupling waste heat recovery and water body heat storage, comprising: a thermal power generation subsystem, a circulating water waste heat utilization subsystem, a water body heat storage subsystem and a heating subsystem;

[0008] The evaporator inlet of the circulating water waste heat utilization subsystem is connected to the circulating water cooling outlet in the condenser of the thermal power generation subsystem, and the circulating water cools the condenser again through the pipeline after releasing the waste heat in the evaporator, thus completing the cycle;

[0009] The water heat exchanger of the water heat storage subsystem is connected to the outlet pipeline of the condensate pump of the thermal power generation subsystem, and part of the condensate flows into the water heater to be heated and then flows into the inlet side of the low-pressure heater downstream of the condensate pump of the thermal power generation subsystem through the pipeline;

[0010] The low-temperature water in the lower layer of the hot water storage body in the water body heat storage subsystem flows into the absorber and condenser of the circulating water waste heat utilization subsystem in sequence through the pipeline for heat exchange, and the high-temperature water formed by the heat exchange returns to the upper high-temperature layer of the hot water storage body through the pipeline;

[0011] The heat network heater in the heating subsystem is connected to the intermediate pressure cylinder of the thermal power generation subsystem. After the intermediate pressure cylinder extracts steam and flows into the heat network heater to release heat, the formed condensed water returns to the inlet side of the low pressure heater through the pipeline;

[0012] The return water on the return water side of the heating network of the heating subsystem enters the water heat exchanger through a pipeline; the return water after absorbing the heat stored in the hot water body by the water heat exchanger enters the heating network heater through a pipeline and then flows into the water supply side of the heating network;

[0013] The return water on the return water side of the heating network of the heating subsystem enters the absorber and condenser of the circulating water waste heat utilization subsystem through pipelines in sequence to absorb low-temperature heat, and the high-temperature water formed by heat exchange flows into the heating network heater through pipelines and then into the water supply side of the heating network.

[0014] Optionally, the thermal power generation subsystem includes a boiler, a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder, a generator, a condenser, a condensate pump, a low-pressure heater, a deaerator, a feed water pump, a high-pressure heater, a circulating water pump and a cooling tower;

[0015] The boiler is connected to the high-pressure cylinder; the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder are connected in sequence; the output end of the low-pressure cylinder is connected to the generator and the condenser respectively; the condenser, the condensate pump, the low-pressure heater, the deaerator, the feed water pump and the high-pressure heater are connected in sequence; the output end of the high-pressure heater is connected to the input end of the boiler; the circulating water pump is used to connect the condenser and the cooling tower.

[0016] Optionally, the circulating water waste heat utilization subsystem includes a generator, a condenser, an absorber, an evaporator, a solution heat exchanger, a solution pump, a refrigerant pump and an expansion valve;

[0017] The evaporator, the absorber, the generator and the condenser are connected in sequence; the solution heat exchanger is arranged between the absorber and the generator; the solution pump is arranged between the absorber and the solution heat exchanger; the refrigerant pump is arranged between the external pipelines of the evaporator; and the expansion valve is arranged in the pipeline between the evaporator and the condenser.

[0018] Optionally, the water body heat storage subsystem includes a hot water storage body, a water body heat exchanger, a hot water user and a water replenishment device;

[0019] The hot water storage body is respectively connected to the water body heat exchanger, the hot water user and the water replenishment device.

[0020] Optionally, the heating subsystem includes a heating network return water side, a heating network supply water side and a heating network heater; the heating network return water side, the heating network heater and the heating network supply water side are connected in sequence.

[0021] Furthermore, it also includes:

[0022] A No. 10 valve and a No. 12 valve are provided on the pipeline between the condenser in the thermal power generation subsystem and the evaporator in the circulating water waste heat utilization subsystem;

[0023] Among them, part of the circulating water flowing through the condenser in the thermal power generation subsystem flows into the evaporator through the pipeline and the No. 10 valve under the drive of the circulating water pump; and the circulating water after releasing the waste heat enters the condenser again through the pipeline and the No. 12 valve to complete the cycle.

[0024] Optionally, the steam extracted from the intermediate pressure cylinder enters the generator through the pipeline and valve No. 24, and the condensed water formed after releasing the heat returns to the inlet side of the low-pressure heater through the pipeline and valve No. 25.

[0025] Optionally, the condensate at the outlet side of the condensate pump flows into the water heat exchanger through the pipeline, valve No. 1 and valve No. 3; and the condensate after heating flows into the inlet side of the low-pressure heater through the pipeline, valve No. 4 and valve No. 2.

[0026] The present invention provides a method for energy storage peak regulation by coupling waste heat recovery and water body heat storage. The method is implemented according to the above-mentioned system. S1. In the non-heating season, when the system needs to participate in peak regulation:

[0027] Extract the exhaust steam from the intermediate pressure cylinder in the thermal power generation subsystem, and the exhaust steam enters the generator in the circulating water waste heat utilization subsystem through the pipeline and valve No. 24; the low-temperature water in the lower layer of the hot water storage body in the water body heat storage subsystem enters the absorber and condenser in the circulating water waste heat utilization subsystem through the pipeline, valve No. 21 and valve No. 23 in sequence for heating; the high-temperature water formed after heating returns to the hot water storage body through the pipeline, valve No. 16 and valve No. 15 for heat storage; part of the circulating water in the thermal power generation subsystem that flows through the condenser enters the evaporator in the circulating water waste heat utilization subsystem through the pipeline and valve No. 10, and returns to the condenser through the pipeline and valve No. 12 for heat absorption after heat release;

[0028] S2, non-heating season, when the system needs peak:

[0029] The condensed water in the thermal power generation subsystem enters the water heat exchanger in the water heat storage subsystem through the pipeline, valve No. 1 and valve No. 3 for heating, and the heated condensed water returns to the inlet side of the low-pressure heater through the pipeline, valve No. 4 and valve No. 2; the high-temperature water in the upper layer of the hot water storage body enters the water heat exchanger through the pipeline and valve No. 13 to release heat; the water after heat release returns to the low-temperature side of the lower layer of the hot water storage body through the pipeline and valve No. 20;

[0030] S3, Heating season, when the system needs to load peak:

[0031] The steps are the same as those for the non-heating season peak load regulation of S1, and the exhaust steam from the medium-pressure cylinder of the thermal power generation subsystem enters the heating heater of the heating subsystem through the pipeline and the No. 7 valve, and the drain water after heat release enters the inlet side of the low-pressure heater through the pipeline, the No. 6 valve and the No. 2 valve; the return water from the return water side of the heating network is heated by the heating network heater and enters the water supply side of the heating network;

[0032] S4, Heating season, when the system needs peak:

[0033] The high-temperature water in the upper layer of the hot water storage body in the circulating water waste heat utilization subsystem enters the water body heat exchanger through the pipeline and valve No. 13 to release heat, and then returns to the lower layer of the hot water storage body through the pipeline and valve No. 20; part of the return water from the return water side of the heating network of the heating subsystem enters the water body heat exchanger through the pipeline, valve No. 8 and valve No. 9 for heating, and then enters the heating network heater through the pipeline and valve No. 5 for secondary heating, and then enters the water supply side of the heating network; part of the return water from the return water side of the heating network enters the absorber and condenser of the circulating water waste heat utilization subsystem through the pipeline, valve No. 19 and valve No. 23 to absorb heat, and then enters the heating network heater through valve No. 17 for secondary heating; the evaporator is the same as the peak regulation, and recovers part of the heat in the circulating water.

[0034] The beneficial effects of the present invention include:

[0035] The new energy storage peak-shaving system proposed in the present invention can be used to solve the energy-saving and carbon-reduction transformation, flexibility transformation and heating transformation problems of cogeneration units at the same time by deeply coupling the circulating water waste heat utilization technology, water body heat storage technology and cogeneration units. First, by recovering the circulating water waste heat, the thermal efficiency of the unit can be improved under the same cogeneration capacity, the coal consumption rate can be reduced, and energy-saving and carbon-reduction transformation can be achieved. Second, after coupling the circulating water waste heat utilization technology with the water body heat storage technology, the system can participate in the peak and peak of the unit throughout the year. The long-term and even cross-season heat storage advantages of large-volume water bodies can solve the source-load mismatch problem to a certain extent, and help achieve flexibility transformation. Third, this technology can achieve the coordination of water body heating, circulating water waste heat recovery heating and original heat network heater heating, reduce coal consumption and deeply participate in the peak-shaving market under the premise of ensuring heating capacity, and help achieve heating transformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a structural schematic diagram of an energy storage peak-shaving system that couples waste heat recovery and water body heat storage in one embodiment of the present disclosure;

[0037] Figure 2 This is a schematic diagram of the system operation structure when the peak load is required during the off-heating season when the electricity consumption is low;

[0038] Figure 3 It is a schematic diagram of the system operation structure in the embodiment of the present disclosure when the peak power demand is at the peak state in the non-heating season;

[0039] Figure 4 This is a schematic diagram of the system operation structure in the embodiment of the present disclosure when the peak load is required during the low electricity consumption in the heating season;

[0040] Figure 5 It is a schematic diagram of the system operation structure when the peak electricity consumption in the heating season is at the peak state in the embodiment of the present disclosure.

[0041] In the figure, 1, boiler; 2, high-pressure cylinder; 3, medium-pressure cylinder; 4, low-pressure cylinder; 5, generator; 6, condenser; 7, condensate pump; 8, low-pressure heater; 9, deaerator;

[0042] 10. Feed water pump; 11. High pressure heater; 12. Circulating water pump; 13. Cooling tower; 14. Hot water storage body; 15. Water body heat exchanger; 16. Generator; 17. Condenser; 18. Absorber; 19. Evaporator; 20. Solution heat exchanger; 21. Solution pump; 22. Refrigerant pump; 23. Expansion valve; 24. Heating network heater; 25. Hot water user; 26. Make-up water device; 27. Heating network return water side; 28. Heating network feed water side; 29. ​​No. 1 valve; 30. No. 2 valve; 31. No. 3 valve; 32. No. 4 valve; 33. No. 5 valve; 34. No. 6 valve; 35. No. 7 valve; 36. No. 8 valve; 37. No. 9 valve; 38. No. 10 valve; 39. No. 11 valve; 40. No. 12 valve; 41. No. 13 valve;

[0043] 42, valve No. 14; 43, valve No. 15; 44, valve No. 16; 45, valve No. 17; 46, valve No. 18; 47, valve No. 19; 48, valve No. 20;

[0044] 49, valve No. 21; 50, valve No. 22; 51, valve No. 23; 52, valve No. 24; 53, valve No. 25. DETAILED DESCRIPTION

[0045] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the present disclosure is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0046] The following is a further detailed description of the implementation methods of the present application in conjunction with the accompanying drawings and examples. The detailed descriptions and drawings of the following examples are used to illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments. In the description of the present application, it should be noted that, unless otherwise specified, the meaning of "multiple" is more than two; the orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "inside", "outside", etc. is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the error tolerance range. "Parallel" is not parallel in the strict sense, but within the error tolerance range.

[0047] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0048] like Figure 1-5 As shown, a storage peak-shaving system that couples waste heat recovery and water heat storage includes a thermal power generation subsystem, a circulating water waste heat utilization subsystem, a water heat storage subsystem and a heating subsystem.

[0049] The inlet of the evaporator 19 of the circulating water waste heat utilization subsystem is connected to the circulating water cooling outlet of the condenser 6 of the thermal power generation subsystem. After the circulating water releases the waste heat in the evaporator 19, it cools the condenser 6 again through the pipeline to complete the cycle;

[0050] The water heat exchanger 15 of the water heat storage subsystem is connected to the outlet pipeline of the condensate pump 7 of the thermal power generation subsystem, and part of the condensate flows into the water heater to be heated and then flows into the inlet side of the low-pressure heater 8 downstream of the condensate pump 7 of the thermal power generation subsystem through the pipeline;

[0051] The lower layer of low-temperature water in the hot water storage body 14 in the water body heat storage subsystem flows into the absorber 18 and the condenser 17 of the circulating water waste heat utilization subsystem through the pipeline in turn for heat exchange, and the high-temperature water formed by the heat exchange returns to the upper layer of the hot water storage body 14 through the pipeline;

[0052] The heat network heater 24 in the heating subsystem is connected to the intermediate pressure cylinder 3 of the thermal power generation subsystem. After the intermediate pressure cylinder 3 extracts steam and flows into the heat network heater 24 to release heat, the formed condensed water returns to the inlet side of the low pressure heater 8 through the pipeline;

[0053] The return water of the heat network return side 27 of the heating subsystem enters the water body heat exchanger 15 through the pipeline; the return water after absorbing the heat stored in the hot water storage body 14 by the water body heat exchanger 15 enters the heat network heater 24 through the pipeline and then flows into the heat network water supply side 28;

[0054] The return water from the heat network return side 27 of the heating subsystem enters the absorber 18 and condenser 17 of the circulating water waste heat utilization subsystem through pipelines to absorb low-temperature heat, and the high-temperature water formed by heat exchange flows into the heat network heater 24 through pipelines and then flows into the heat network feed water side 28.

[0055] The beneficial effects of the present disclosure include: 1. The present disclosure couples the circulating water waste heat recovery technology and the water body heat storage technology, which can simultaneously achieve energy saving and carbon reduction, flexibility and heating transformation. 2. The heat source of this patent is divided into two parts, one part is the heating extraction steam, and the other part is the waste heat in the recovered circulating water. Compared with traditional electric heat storage or high-temperature heat storage, it has the advantage of reducing the coal consumption rate of the unit. 3. The present patent utilizes a large-volume hot water storage body 14 (hot water storage tank) for long-term heat storage of low-grade heat, which is more thermally economical, and the larger the water volume, the larger the heat storage capacity, the higher the heat storage efficiency, the longer the heat storage time, and the lower the construction cost.

[0056] In some embodiments, the thermal power generation subsystem includes a boiler 1, a high-pressure cylinder 2, a medium-pressure cylinder 3, a low-pressure cylinder 4, a generator 5, a condenser 6, a condensate pump 7, a low-pressure heater 8, a deaerator 9, a feed water pump 10, a high-pressure heater 11, a circulating water pump 12 and a cooling tower 13.

[0057] The boiler 1 is connected to the high-pressure cylinder 2. The high-pressure cylinder 2, the medium-pressure cylinder 3 and the low-pressure cylinder 4 are connected in sequence. The output end of the low-pressure cylinder 4 is connected to the generator 5 and connected to the condenser 6. The condenser 6, the condensate pump 7, the low-pressure heater 8, the deaerator 9, the feed water pump 10 and the high-pressure heater 11 are connected in sequence. The output end of the high-pressure heater 11 is connected to the input end of the boiler 1, and the cooling tower 13 is set in the pipeline between the condenser 6 and the circulating water pump 12.

[0058] In some embodiments, the circulating water waste heat utilization subsystem includes a generator 16 , a condenser 17 , an absorber 18 , an evaporator 19 , a solution heat exchanger 20 , a solution pump 21 , a refrigerant pump 22 and an expansion valve 23 .

[0059] The evaporator 19, the absorber 18, the solution heat exchanger 20, the generator 16 and the condenser 17 are connected in sequence. The solution pump 21 is arranged in the pipeline between the absorber 18 and the solution heat exchanger 20. The refrigerant pump 22 is arranged in the evaporator 19, and the expansion valve 23 is arranged in the pipeline between the evaporator 19 and the condenser 17.

[0060] In some embodiments, the water body heat storage subsystem includes a hot water storage body 14, a water body heat exchanger 15, a hot water user 25 and a water replenishing device 26. The hot water storage body 14 is connected to the water body heat exchanger 15, the hot water user 25 and the water replenishing device 26 respectively.

[0061] In some embodiments, the heating subsystem includes a heating network return water side 27, a heating network supply water side 28 and a heating network heater 24. The heating network return water side 27 is respectively connected to the inlet pipeline of the absorber 18 in the circulating water waste heat utilization subsystem and the inlet pipeline of the water heat exchanger 15 in the water body heat storage subsystem, and is also connected to the heating network heater 24 and the heating network supply water side 28.

[0062] In some embodiments, the energy storage peak regulation system further includes: a No. 10 valve 38 and a No. 12 valve 40 are arranged on the pipeline between the condenser 6 and the evaporator 19. Part of the circulating water of the thermal power generation subsystem flowing through the condenser 6 flows into the evaporator 19 through the pipeline and the No. 10 valve 38 driven by the circulating water pump 12, and the circulating water after releasing the waste heat enters the condenser 6 again through the pipeline and the No. 12 valve 40 to complete the cycle.

[0063] In some embodiments, the medium-pressure cylinder 3 is connected to the input end of the generator 16 through a pipeline, and the output end of the generator 16 is connected to the inlet side of the low-pressure heater 8 through a pipeline.

[0064] The unit also includes: a No. 24 valve 52 is arranged on the pipeline between the medium-pressure cylinder 3 and the input end of the generator 16, and a No. 25 valve 53 is arranged on the pipeline between the output end of the generator 16 and the inlet end of the low-pressure heater 8.

[0065] Among them, the steam extracted from the medium-pressure cylinder 3 enters the generator 16 through the pipeline and the No. 24 valve 52, and the condensed water formed after releasing the heat returns to the inlet side of the low-pressure heater 8 through the pipeline and the No. 25 valve 53.

[0066] In some embodiments, the outlet of the condensate pump 7 is connected to the input end of the water heat exchanger 15 through a pipeline, and the output end of the water heat exchanger 15 is connected to the inlet side of the low-pressure heater 8 through a pipeline.

[0067] The unit also includes: a No. 1 valve 29 and a No. 3 valve 31 are sequentially arranged on the pipeline between the condensate pump 7 and the water heat exchanger 15, and a No. 4 valve 32 and a No. 2 valve 30 are sequentially arranged on the pipeline between the water heat exchanger 15 and the low-pressure heater 8.

[0068] Among them, the condensate at the outlet side of the condensate pump 7 flows into the water heat exchanger 15 through the pipeline, valve No. 1 29 and valve No. 31, and the condensate after heating flows into the inlet side of the low-pressure heater 8 through the pipeline, valve No. 4 32 and valve No. 2 30.

[0069] The beneficial effects of the present disclosure include: 1) The present disclosure can simultaneously realize energy-saving and carbon-reduction transformation, flexibility transformation and heating transformation of the cogeneration unit.

[0070] 2) It can realize the recovery of waste heat of circulating water, reduce the temperature of circulating water, and improve the vacuum degree of condenser 6.

[0071] 3) Use steam extraction to drive water source heat pump technology for heat storage and assist in peak load regulation of the unit.

[0072] 4) After coupling the water body heat storage subsystem, the heat pump unit in the circulating water waste heat utilization subsystem can be put into operation throughout the year, and the amount of recoverable circulating water waste heat is greatly increased. At the same time, it can participate in the peak load regulation of the unit throughout the year.

[0073] A specific example provided by the present disclosure provides an energy storage peak-shaving system that simultaneously achieves energy conservation and carbon reduction, flexibility and heating transformation, and the unit includes a thermal power generation subsystem, a circulating water waste heat utilization subsystem, a water body heat storage subsystem and a heating subsystem.

[0074] The thermal power generation subsystem includes a boiler 1, a high-pressure cylinder 2, a medium-pressure cylinder 3, a low-pressure cylinder 4, a generator 5, a condenser 6, a condensate pump 7, a low-pressure heater 8, a deaerator 9, a feed water pump 10, a high-pressure heater 11, a circulating water pump 12 and a cooling tower 13.

[0075] The circulating water waste heat utilization subsystem includes a generator 16 , a condenser 17 , an absorber 18 , an evaporator 19 , a solution heat exchanger 20 , a solution pump 21 , a refrigerant pump 22 and an expansion valve 23 .

[0076] The water body heat storage subsystem mainly includes a hot water storage body 14 , a water body heat exchanger 15 , a hot water user 25 and a water replenishment device 26 .

[0077] The heating subsystem mainly includes the heat network return water side 27 , the heat network feed water side 28 and the heat network heater 24 .

[0078] The thermal power generation subsystem and the circulating water waste heat utilization subsystem are connected in the following manner: part of the circulating water flowing through the condenser 6 flows into the evaporator 19 through the pipeline and the No. 10 valve 38 driven by the circulating water pump 12, and after releasing the waste heat, it enters the condenser 6 again through the pipeline and the No. 12 valve 40 to complete the cycle. Furthermore, the steam extraction from the intermediate pressure cylinder 3 enters the generator 16 through the pipeline and the No. 24 valve 52, and returns to the inlet side of the low-pressure heater 8 through the pipeline and the No. 25 valve 53 after releasing the heat.

[0079] The connection mode between the thermal power generation subsystem and the water heat storage subsystem is as follows: the condensate at the outlet side of the condensate pump 7 flows into the water heat exchanger 15 through the pipeline, valve No. 1 29 and valve No. 3 31, and after heating, flows into the inlet side of the low-pressure heater 8 through the pipeline, valve No. 4 32 and valve No. 2 30.

[0080] The connection between the thermal power generation subsystem and the heating subsystem is as follows: the steam extracted from the medium-pressure cylinder 3 flows into the heat network heater 24 through the pipeline and the No. 7 valve 35 to release heat, and then returns to the inlet side of the low-pressure heater 8 through the pipeline, the No. 6 valve 34 and the No. 2 valve 30.

[0081] The connection mode between the circulating water waste heat utilization subsystem and the water body heat storage subsystem is as follows: the low-temperature water in the lower layer of the hot water storage body 14 flows into the absorber 18 to absorb low-temperature heat through the pipeline, the No. 21 valve 49 and the No. 23 valve 51. Further, it flows into the condenser 17 to absorb high-temperature heat, and then returns to the high-temperature layer above the hot water storage body 14 through the pipeline, the No. 16 valve 44 and the No. 15 valve 43.

[0082] The connection between the water body heat storage subsystem and the heating subsystem is as follows: the return water from the return water side 27 of the heating network enters the water body heat exchanger 15 through the pipeline, valve No. 8 36 and valve No. 9 37, absorbs the heat stored in the hot water storage body 14, enters the heating network heater 24 through the pipeline and valve No. 5 33, and then flows into the water supply side 28 of the heating network.

[0083] The connection between the circulating water waste heat utilization subsystem and the heating subsystem is as follows: the return water from the return water side 27 of the heating network enters the absorber 18 to absorb low-temperature heat through the pipeline, the 19th valve 47 and the 23rd valve 51. Further, it flows into the condenser 17 to absorb high-temperature heat, flows into the heating network heater 24 through the pipeline and the 17th valve 45, and then flows into the heating network water supply side 28.

[0084] In some embodiments, the hot water storage body 14 is an artificial or natural hot water storage pool with a volume of tens of thousands to millions of cubic meters. Combined with insulation materials, anti-seepage materials, water distributors and other materials and equipment, it can achieve long-term or even cross-season heat storage. Further, the hot water storage body 14 has a pipeline directly connected to the hot water user 25 and a No. 14 valve 42, as well as a corresponding pipeline connected to the water replenishment device 26 and a No. 22 valve 50.

[0085] In some embodiments, the circulating water waste heat utilization subsystem adopts water source absorption heat pump technology. The dilute solution composed of refrigerant and absorbent is driven by the solution pump 21 through the solution heat exchanger 20 to enter the generator 16, and absorbs the heat in the extraction steam from the thermal power generation subsystem in the generator 16. The refrigerant evaporates and enters the condenser 17. The concentrated solution with a higher temperature heats the dilute solution in the solution heat exchanger 20 and then flows into the absorber 18. The high-temperature and high-pressure refrigerant heats the return water of the heat network or the water body in the condenser 17, and then flows through the expansion valve 23 to reduce the pressure, enters the evaporator 19 to absorb the waste heat of the circulating water from the thermal power generation subsystem to complete the evaporation process, and finally enters the absorber 18 to mix with the concentrated solution to form a dilute solution. The released absorption heat is used to preliminarily heat the return water of the heat network or the water body.

[0086] The new energy storage peak-shaving system proposed in the present invention deeply couples the circulating water waste heat utilization technology, water body heat storage technology and the cogeneration unit, and can be used to achieve energy-saving and carbon-reduction transformation, flexibility transformation and heating transformation of the cogeneration unit at the same time. First, by recovering the circulating water waste heat, the thermal efficiency of the unit can be improved under the same cogeneration capacity, and the coal consumption rate can be reduced, which helps to achieve energy-saving and carbon-reduction transformation. Second, by coupling the circulating water waste heat recovery technology with the water body heat storage technology, the system can participate in peak-shaving throughout the year. The long-term or even cross-season heat storage of large-volume water bodies can solve the source-load mismatch problem to a certain extent, and help achieve flexibility transformation. Third, this technology can achieve the coordination of water body heating, circulating water waste heat recovery heating and original heat network heater 24 heating, reduce coal consumption and deeply participate in the peak-shaving market under the premise of ensuring heating capacity, and help achieve heating transformation.

[0087] A second aspect of the embodiments of the present disclosure provides a method for energy storage peak regulation by coupling waste heat recovery and water body heat storage. The method is implemented according to the above-mentioned unit and specifically includes:

[0088] In the non-heating season, when the energy storage peak-shaving system needs to participate in the peak-shaving state:

[0089] S101, extract the exhaust steam from the medium pressure cylinder 3 in the thermal power generation subsystem, and the exhaust steam enters the generator 16 in the circulating water waste heat utilization subsystem through the pipeline and the No. 24 valve 52. This setting method reduces the amount of steam entering the low pressure cylinder 4 to reduce the power generation load.

[0090] S102, the low-temperature water in the lower layer of the hot water storage body 14 in the water body heat storage subsystem enters the absorber 18 and the condenser 17 in the circulating water waste heat utilization subsystem through the pipeline, valve No. 21 49 and valve No. 23 51 in sequence for heating.

[0091] S103, the high-temperature water formed after heating is returned to the hot water storage body 14 through the pipeline and the sixteenth valve 44 to store heat.

[0092] In some embodiments, during the non-heating season, when the energy storage peak-shaving system needs to participate in the peak state:

[0093] S201, the condensate in the thermal power generation subsystem enters the water heat exchanger 15 in the water heat storage subsystem through the pipeline, the No. 1 valve 29 and the No. 3 valve 31 for heating, and the heated condensate returns to the inlet side of the low-pressure heater 8 through the pipeline, the No. 4 valve 32 and the No. 2 valve 30. This setting can reduce the heat recovery steam extraction of the low-pressure cylinder 4 and increase the power generation load of the unit.

[0094] S202, the high-temperature water in the upper layer of the hot water storage body 14 enters the water body heat exchanger 15 through the pipeline and the thirteenth valve 41 to release heat.

[0095] S203, returning the upper layer of high-temperature water after heat release to the lower layer of the hot water storage body 14 through the pipeline and valve No. 20 48.

[0096] In some embodiments, reference Figure 4 In the heating season, when the thermal power unit needs to be in peak load regulation state:

[0097] S301. Most of the steam extracted from the intermediate pressure cylinder 3 in the thermal power generation subsystem enters the heat network heater 24 in the heating subsystem through the pipeline and the No. 7 valve 35 to meet the heat load demand.

[0098] S302, a small amount of steam extracted from the intermediate pressure cylinder 3 enters the circulating water waste heat utilization subsystem through the pipeline and valve No. 24 52 to recover the circulating water waste heat, and the generated heat is stored in the hot water storage body 14.

[0099] Specifically, the extraction steam in the medium pressure cylinder 3 exchanges heat with the generator 16, and the condensed water formed flows through valve No. 25, valve No. 6 and valve No. 2 and returns to the inlet side of the low pressure heater 8. The condenser 17 in the circulating water waste heat utilization subsystem heats the low temperature water in the lower layer of the hot water storage body 14, and then returns to the upper layer of the hot water storage body 14 to achieve heat storage.

[0100] S303, the return water from the return water side 27 of the heating network enters the heating network heater 24 through the pipeline and the No. 18 valve 46 for heating, and finally flows into the heating network feed water side 28. In this scheme, the functions of steam extraction peak regulation, circulating water waste heat recovery and heat storage are realized in the non-heating season.

[0101] In some embodiments, reference Figure 5 , during the heating season, when the thermal power units need to be at peak status:

[0102] S401, the return water of the heat network return side 27 of the heating subsystem is distributed through the No. 8 valve 36, the No. 19 valve 47 and the No. 18 valve 46, wherein the No. 8 valve 36 controls the flow of the return water of the heat network into the water heat exchanger 15 of the water body heat storage subsystem to absorb the heat stored in the water body. Among them, the No. 19 valve 47 controls the flow of the return water of the heat network into the circulating water waste heat utilization subsystem, and recovers the waste heat of the circulating water for heating under the drive of extraction steam.

[0103] S402, the remaining return water flow on the return water side 27 of the heating network is merged with the return water from the circulating water waste heat recovery subsystem and the water body heat storage subsystem after heating through the pipeline and valve No. 18 46, enters the heating network heater 24 of the heating subsystem to be heated to the specified temperature, and finally enters the water supply side 28 of the heating network.

[0104] In the present disclosure, the heat stored in the water body and the waste heat of the circulating water are simultaneously used to heat the return water of the heat network, which can reduce the steam extraction for heating and improve the peak capacity of the unit at this time.

[0105] In the present disclosure, the off-heating season peak-shaving and heating season peak operation modes are provided. When the peak-shaving heat storage power of the hot water storage body 14 in the water body heat storage subsystem during the off-heating season is greater than the peak heat release power, the heat can be stored until the heating period and used to heat the heat network return water in the heating subsystem during the heating period, thereby improving the peak capacity of the heating period.

[0106] Furthermore, in the year-round auxiliary frequency regulation operation mode, the exhaust steam of the medium-pressure cylinder 3 of the thermal power generation subsystem is extracted into the circulating water waste heat utilization subsystem, which can quickly reduce the output of the low-pressure cylinder 4 and the power generation load of the unit, thereby assisting the frequency regulation of the cogeneration unit.

[0107] Furthermore, the stored heat in the non-heating season is used to heat the condensate, reducing the steam extraction of the condensate pump 7 and the low-pressure heater 8, thereby increasing the power generation of the unit.

[0108] Furthermore, the water body disclosed in the present invention can store heat for a long time across seasons, storing in summer and releasing in winter, thus solving the problem of mismatch between peak load regulation and heating time.

[0109] Furthermore, during the heating season, the hot water storage body 14 and the water source heat pump are given priority in heating, which reduces the steam extraction for heating of the unit and assists the peak operation of the unit.

[0110] In the present disclosure, in the non-heating season, it is possible to store heat and shave peak loads by recovering the waste heat of circulating water, and to release heat by heating the feed water for peak loads. In the heating season, it is also possible to store heat and shave peak loads by recovering the waste heat of circulating water, and to release heat by heating the return water of the heat network for peak loads. The energy storage and peak-shaving system and operation method provided by the present invention enable the cogeneration unit to recover the waste heat of circulating water for heat storage and increase the depth of peak-shaving during peak loads throughout the year. The stored heat can help the unit reach its peak and alleviate the thermal-electric contradiction of the thermal power unit.

[0111] Specifically, S1, in the non-heating season, when the system needs to participate in peak load regulation:

[0112] Extract exhaust steam from the intermediate pressure cylinder in the thermal power generation subsystem, and the exhaust steam enters the generator in the circulating water waste heat utilization subsystem through the pipeline and valve No. 24; the low-temperature water in the lower layer of the hot water storage body in the water body heat storage subsystem enters the absorber and condenser in the circulating water waste heat utilization subsystem through the pipeline, valve No. 21 and valve No. 23 in sequence for heating; the high-temperature water formed after heating returns to the hot water storage body through the pipeline, valve No. 16 and valve No. 15 for heat storage; part of the circulating water in the thermal power generation subsystem that flows through the condenser enters the evaporator in the circulating water waste heat utilization subsystem through the pipeline and valve No. 10, and returns to the condenser through the pipeline and valve No. 12 for heat absorption after releasing heat.

[0113] S2, non-heating season, when the system needs peak:

[0114] The condensate in the thermal power generation subsystem enters the water heat exchanger in the water heat storage subsystem through pipelines, valve No. 1 and valve No. 3 for heating, and the heated condensate returns to the inlet side of the low-pressure heater through pipelines, valve No. 4 and valve No. 2; the high-temperature water in the upper layer of the hot water storage body enters the water heat exchanger through pipelines and valve No. 13 to release heat; the water after heat release returns to the low-temperature side of the lower layer of the hot water storage body through pipelines and valve No. 20.

[0115] S3, Heating season, when the system needs to load peak:

[0116] The steps are the same as those for peak load regulation of the non-heating season system of S1, and the exhaust steam from the medium-pressure cylinder of the thermal power generating subsystem enters the heating heater of the heating subsystem through the pipeline and valve No. 7, and the drain water after heat release enters the inlet side of the low-pressure heater through the pipeline, valve No. 6 and valve No. 2; the return water from the return water side of the heating network is heated by the heating network heater and then enters the feed water side of the heating network.

[0117] S4, Heating season, when the system needs peak:

[0118] The high-temperature water in the upper layer of the hot water storage body in the circulating water waste heat utilization subsystem enters the water body heat exchanger through the pipeline and valve No. 13 to release heat, and then returns to the lower layer of the hot water storage body through the pipeline and valve No. 20; part of the return water from the return water side of the heating network of the heating subsystem enters the water body heat exchanger through the pipeline, valve No. 8 and valve No. 9 for heating, and then enters the heating network heater through the pipeline and valve No. 5 for secondary heating, and then enters the water supply side of the heating network; part of the return water from the return water side of the heating network enters the absorber and condenser of the circulating water waste heat utilization subsystem through the pipeline, valve No. 19 and valve No. 23 to absorb heat, and then enters the heating network heater through valve No. 17 for secondary heating; the evaporator is the same as the peak regulation, and recovers part of the heat in the circulating water.

[0119] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. An energy storage peak regulation system coupling waste heat recovery and water body heat storage, characterized in that: include: Thermal power generation subsystem, circulating water waste heat utilization subsystem, water body heat storage subsystem and heating subsystem; The evaporator inlet of the circulating water waste heat utilization subsystem is connected to the circulating water cooling outlet in the condenser of the thermal power generation subsystem, and the circulating water cools the condenser again through the pipeline after releasing the waste heat in the evaporator, thus completing the cycle; The water heat exchanger of the water heat storage subsystem is connected to the outlet pipeline of the condensate pump of the thermal power generation subsystem, and part of the condensate flows into the water heater to be heated and then flows into the inlet side of the low-pressure heater downstream of the condensate pump of the thermal power generation subsystem through the pipeline; The low-temperature water in the lower layer of the hot water storage body in the water body heat storage subsystem flows into the absorber and condenser of the circulating water waste heat utilization subsystem in sequence through the pipeline for heat exchange, and the high-temperature water formed by the heat exchange returns to the upper high-temperature layer of the hot water storage body through the pipeline; The heat network heater in the heating subsystem is connected to the intermediate pressure cylinder of the thermal power generation subsystem. After the intermediate pressure cylinder extracts steam and flows into the heat network heater to release heat, the formed condensed water returns to the inlet side of the low pressure heater through the pipeline; The return water on the return water side of the heating network of the heating subsystem enters the water heat exchanger through a pipeline; the return water after absorbing the heat stored in the hot water body by the water heat exchanger enters the heating network heater through a pipeline and then flows into the water supply side of the heating network; The return water on the return water side of the heating network of the heating subsystem enters the absorber and condenser of the circulating water waste heat utilization subsystem through pipelines in sequence to absorb low-temperature heat, and the high-temperature water formed by heat exchange flows into the heating network heater through pipelines and then into the water supply side of the heating network.

2. The energy storage peak-shaving system coupling waste heat recovery and water body heat storage according to claim 1 is characterized in that: The thermal power generation subsystem includes a boiler, a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder, a generator, a condenser, a condensate pump, a low-pressure heater, a deaerator, a feed water pump, a high-pressure heater, a circulating water pump and a cooling tower; The boiler is connected to the high-pressure cylinder; the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder are connected in sequence; the output end of the low-pressure cylinder is connected to the generator and the condenser respectively; the condenser, the condensate pump, the low-pressure heater, the deaerator, the feed water pump and the high-pressure heater are connected in sequence; the output end of the high-pressure heater is connected to the input end of the boiler; the circulating water pump is used to connect the condenser and the cooling tower.

3. The energy storage peak-shaving system coupling waste heat recovery and water body heat storage according to claim 2 is characterized in that: The circulating water waste heat utilization subsystem includes a generator, a condenser, an absorber, an evaporator, a solution heat exchanger, a solution pump, a refrigerant pump and an expansion valve; The evaporator, the absorber, the generator and the condenser are connected in sequence; the solution heat exchanger is arranged between the absorber and the generator; the solution pump is arranged between the absorber and the solution heat exchanger; the refrigerant pump is arranged between the external pipelines of the evaporator; and the expansion valve is arranged in the pipeline between the evaporator and the condenser.

4. The energy storage peak-shaving system coupling waste heat recovery and water body heat storage according to claim 3 is characterized in that: The water body heat storage subsystem includes a hot water storage body, a water body heat exchanger, a hot water user and a water replenishment device; The hot water storage body is respectively connected to the water body heat exchanger, the hot water user and the water replenishment device.

5. The energy storage peak-shaving system coupling waste heat recovery and water body heat storage according to claim 4 is characterized in that: The heating subsystem includes a heat network return water side, a heat network supply water side and a heat network heater; the heat network return water side, the heat network heater and the heat network supply water side are connected in sequence.

6. The energy storage peak-shaving system coupling waste heat recovery and water body heat storage according to claim 5 is characterized in that: Also includes: A No. 10 valve and a No. 12 valve are provided on the pipeline between the condenser in the thermal power generation subsystem and the evaporator in the circulating water waste heat utilization subsystem; Among them, part of the circulating water flowing through the condenser in the thermal power generation subsystem flows into the evaporator through the pipeline and the No. 10 valve under the drive of the circulating water pump; and the circulating water after releasing the waste heat enters the condenser again through the pipeline and the No. 12 valve to complete the cycle.

7. The energy storage peak-shaving system coupling waste heat recovery and water body heat storage according to claim 5 is characterized in that: The steam extracted from the medium-pressure cylinder enters the generator through the pipeline and valve No. 24, and the condensed water formed after releasing the heat returns to the inlet side of the low-pressure heater through the pipeline and valve No.

25.

8. The energy storage peak-shaving system coupling waste heat recovery and water body heat storage according to claim 5 is characterized in that: The condensate at the outlet side of the condensate pump flows into the water heat exchanger through the pipeline, valve No. 1 and valve No. 3; and the condensate after heating flows into the inlet side of the low-pressure heater through the pipeline, valve No. 4 and valve No.

2.

9. A method for energy storage peak regulation by coupling waste heat recovery and water body heat storage, the method is implemented according to the system according to any one of claims 1 to 8, characterized in that: S1. In the non-heating season, when the system needs to participate in peak load regulation: Extract the exhaust steam from the intermediate pressure cylinder in the thermal power generation subsystem, and the exhaust steam enters the generator in the circulating water waste heat utilization subsystem through the pipeline and valve No. 24; the low-temperature water in the lower layer of the hot water storage body in the water body heat storage subsystem enters the absorber and condenser in the circulating water waste heat utilization subsystem through the pipeline, valve No. 21 and valve No. 23 in sequence for heating; the high-temperature water formed after heating returns to the hot water storage body through the pipeline, valve No. 16 and valve No. 15 for heat storage; part of the circulating water in the thermal power generation subsystem that flows through the condenser enters the evaporator in the circulating water waste heat utilization subsystem through the pipeline and valve No. 10, and returns to the condenser through the pipeline and valve No. 12 for heat absorption after heat release; S2, non-heating season, when the system needs peak: The condensed water in the thermal power generation subsystem enters the water heat exchanger in the water heat storage subsystem through the pipeline, valve No. 1 and valve No. 3 for heating, and the heated condensed water returns to the inlet side of the low-pressure heater through the pipeline, valve No. 4 and valve No. 2; the high-temperature water in the upper layer of the hot water storage body enters the water heat exchanger through the pipeline and valve No. 13 to release heat; the water after heat release returns to the low-temperature side of the lower layer of the hot water storage body through the pipeline and valve No. 20; S3, Heating season, when the system needs to load peak: The steps are the same as those for the non-heating season peak load regulation of S1, and the exhaust steam from the medium-pressure cylinder of the thermal power generation subsystem enters the heating heater of the heating subsystem through the pipeline and the No. 7 valve, and the drain water after heat release enters the inlet side of the low-pressure heater through the pipeline, the No. 6 valve and the No. 2 valve; the return water from the return water side of the heating network is heated by the heating network heater and enters the water supply side of the heating network; S4, Heating season, when the system needs peak: The high-temperature water in the upper layer of the hot water storage body in the circulating water waste heat utilization subsystem enters the water body heat exchanger through the pipeline and valve No. 13 to release heat, and then returns to the lower layer of the hot water storage body through the pipeline and valve No. 20; part of the return water from the return water side of the heating network of the heating subsystem enters the water body heat exchanger through the pipeline, valve No. 8 and valve No. 9 for heating, and then enters the heating network heater through the pipeline and valve No. 5 for secondary heating, and then enters the water supply side of the heating network; part of the return water from the return water side of the heating network enters the absorber and condenser of the circulating water waste heat utilization subsystem through the pipeline, valve No. 19 and valve No. 23 to absorb heat, and then enters the heating network heater through valve No. 17 for secondary heating; the evaporator is the same as the peak regulation, and recovers part of the heat in the circulating water.

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