A thermal energy storage power generation system and an operation method thereof

Abstract

The present invention relates to the field of power generation technology, and particularly relates to a heat storage power generation system and an operation method. The heat storage power generation system includes: a boiler, a first steam turbine, and a second steam turbine connected in sequence; a first heat storage tank is connected to the boiler through a first valve; a second heat storage tank is connected between the second steam turbine and the first steam turbine through a second valve; the operation method includes: making the rotational speed of the first steam turbine less than a first predetermined value through the first valve; making the rotational speed of the second steam turbine less than the first predetermined value through the second valve; in this application, part of the main steam is absorbed by the first heat storage tank to reduce the rotational speed of the first steam turbine; part of the reheated steam is absorbed by the second heat storage tank to reduce the rotational speed of the second steam turbine; the rotational speeds of the first steam turbine and the second steam turbine are stably coordinated to ensure the grid frequency.

Description

Technical Field

[0001] The present invention relates to the technical field of power generation, and particularly relates to a heat storage power generation system and an operation method thereof. Background Art

[0002] In the current power system, coal-fired generating units are important power supply sources. At present, the coal-fired boiler and the steam turbine are arranged at different heights. The main steam outlet of the boiler is at a high position, while the steam inlet of the steam turbine is at a low position. The main steam needs to pass through a long pipeline from the boiler to the steam turbine, and the resulting pressure loss and heat loss have a greater impact on the efficiency of the unit. As the maximum load of the unit continues to increase, the parameters of the main steam of the boiler also increase, and the resulting losses also increase. The measure of arranging the steam turbine at different heights can effectively avoid the above problems.

[0003] However, the high-pressure steam turbine and the low-pressure steam turbine are not coaxial, and their rotational speeds are independent and unstable, making it difficult to ensure the power grid frequency. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the rotational speeds of the high-pressure steam turbine and the low-pressure steam turbine in the prior art are independent and unstable, making it difficult to ensure the power grid frequency. Based on the above situation, it is very necessary to develop a heat storage power generation system that stabilizes the rotational speeds of the high-pressure steam turbine and the low-pressure steam turbine.

[0005] To achieve the above object, the present invention provides a heat storage power generation system, including:

[0006] A boiler, a first steam turbine, and a second steam turbine connected in sequence, and the first steam turbine and the second steam turbine are not coaxial;

[0007] A first heat storage tank, connected to the boiler through a first valve;

[0008] A second heat storage tank, connected to the pipeline between the second steam turbine and the first steam turbine through a second valve.

[0009] Optionally, it further includes:

[0010] A condenser, a low-pressure heater, a deaerator, and a high-pressure heater connected in sequence;

[0011] The condensate outlet of the condenser is communicated with the water inlet of the second heat storage tank through a fourth valve;

[0012] The water outlet of the second heat storage tank is communicated with the water inlet of the deaerator.

[0013] Optionally, the water outlet of the second heat storage tank is communicated with the water inlet of the first heat storage tank through a fifth valve;

[0014] The water inlet of the first heat storage tank is communicated with the water outlet of the deaerator through a third valve;

[0015] The water outlet of the first heat storage tank is communicated with the water inlet of the boiler through a sixth valve.

[0016] Optionally, the steam at the steam outlet of the first steam turbine forms reheated steam after passing through the boiler and then enters the steam inlet of the second steam turbine.

[0017] Optionally, heat storage media are provided in both the first heat storage tank and the second heat storage tank.

[0018] Optionally, temperature sensors are provided on both the first heat storage tank and the second heat storage tank;

[0019] The temperature range in the first heat storage tank is: 300 - 500 °C;

[0020] The temperature range in the second heat storage tank is: 200 - 350 °C.

[0021] Optionally, the steam inlet of the first heat storage tank is connected to a first valve, and the steam outlet of the first heat storage tank is communicated with the steam inlet of the deaerator;

[0022] The steam inlet of the second heat storage tank is connected to a second valve, and the steam outlet of the second heat storage tank is communicated with the steam inlet of the low-pressure heater.

[0023] The present invention also provides an operation method for the heat storage power generation system, including:

[0024] When the rotational speed of the first steam turbine is greater than a first predetermined value and the rotational speed of the second steam turbine is less than a second predetermined value, open the first valve so that part of the main steam in the boiler enters the first heat storage tank, and close the first valve until the rotational speed of the first steam turbine is less than the first predetermined value;

[0025] When the rotational speed of the second steam turbine is greater than a first predetermined value and the rotational speed of the first steam turbine is less than a first predetermined value, open the second valve so that part of the reheated steam in the boiler enters the second heat storage tank, and close the second valve until the rotational speed of the second steam turbine is less than the first predetermined value;

[0026] When the rotational speeds of both the first steam turbine and the second steam turbine are greater than a first predetermined value, first open the first valve so that part of the main steam in the boiler enters the first heat storage tank, and then open the second valve so that part of the reheated steam in the boiler enters the second heat storage tank, and close the first valve and the second valve until the rotational speeds of both the first steam turbine and the second steam turbine are less than the first predetermined value.

[0027] Optionally, when the rotational speed of the first steam turbine is greater than a first predetermined value and the rotational speed of the second steam turbine is less than a second predetermined value, open the first valve so that a part of the main steam in the boiler enters the first heat storage tank until the rotational speed of the first steam turbine is less than the first predetermined value, then close the first valve;

[0028] When the rotational speed of the second steam turbine is greater than the first predetermined value and the rotational speed of the first steam turbine is less than the first predetermined value, open the second valve so that a part of the reheated steam in the boiler enters the second heat storage tank until the rotational speed of the second steam turbine is less than the first predetermined value, then close the second valve;

[0029] When the rotational speeds of both the first steam turbine and the second steam turbine are greater than the first predetermined value, first open the first valve so that a part of the main steam in the boiler enters the first heat storage tank, and then open the second valve so that a part of the reheated steam in the boiler enters the second heat storage tank until the rotational speeds of both the first steam turbine and the second steam turbine are less than the first predetermined value, then close the first valve and the second valve;

[0030] When the rotational speeds of both the first steam turbine and the second steam turbine are less than a third predetermined value, or when it is necessary to increase the system load, open the fourth valve so that a part of the condensed water in the condenser enters the second heat storage tank to be heated.

[0031] Optionally, when the temperature in the first heat storage tank is greater than the set temperature, open the fifth valve and close the sixth valve, so that the water flowing out of the second heat storage tank enters the first heat storage tank to be further heated into steam and enters the deaerator;

[0032] When the temperature in the first heat storage tank is less than the set temperature, close the fifth valve, open the sixth valve and the third valve, so that the water flowing out of the second heat storage tank passes through the deaerator and the first heat storage tank in sequence and returns to the boiler.

[0033] The above technical solution of the present invention has the following advantages compared with the prior art:

[0034] 1. The thermal energy storage power generation system provided by the present invention includes: a boiler, a first steam turbine, and a second steam turbine connected in sequence, where the first steam turbine and the second steam turbine are not coaxially arranged; a first thermal energy storage tank connected to the boiler through a first valve; a second thermal energy storage tank connected to the pipeline between the second steam turbine and the first steam turbine through a second valve. By adopting the above technical solution, the present application absorbs the steam volume entering the first steam turbine through the first thermal energy storage tank to reduce the rotational speed of the first steam turbine; releases the heat of the first thermal energy storage tank to increase the steam volume entering the first steam turbine and improve the rotational speed of the first steam turbine; absorbs the steam volume entering the second steam turbine through the second thermal energy storage tank to reduce the rotational speed of the second steam turbine; releases the heat of the second thermal energy storage tank to increase the steam volume entering the second steam turbine and improve the rotational speed of the second steam turbine; thereby coordinately regulating and stabilizing the rotational speeds of the first steam turbine and the second steam turbine to ensure the grid frequency and the high efficiency of the unit; the modification of the unit is small, there is no need to modify the unit body, and the cost is relatively low.

[0035] 2. The thermal energy storage power generation system provided by the present invention further includes: a condenser, a low-pressure heater, a deaerator, and a high-pressure heater connected in sequence; the condensate outlet of the condenser is communicated with the water inlet of the second thermal energy storage tank through a fourth valve; the water outlet of the second thermal energy storage tank is communicated with the water inlet of the deaerator. By adopting the above technical solution, not only the reheated steam stores and releases heat in the second thermal energy storage tank, but also the condensate of the condenser is used for heat storage and release, improving the heat storage and release efficiency.

[0036] 3. The water outlet of the second thermal energy storage tank of the present invention is communicated with the water inlet of the first thermal energy storage tank through a fifth valve; the water inlet of the first thermal energy storage tank is communicated with the water outlet of the deaerator through a third valve; the water outlet of the first thermal energy storage tank is communicated with the water inlet of the boiler through a sixth valve. By adopting the above technical solution, not only the first thermal energy storage tank and the second thermal energy storage tank store and release heat independently, but also by using the connection between the first thermal energy storage tank and the second thermal energy storage tank, the thermal energy of the first thermal energy storage tank and the second thermal energy storage tank is reasonably utilized, improving the heat storage and release efficiency.

[0037] 4. The steam at the steam outlet of the first steam turbine of the present invention forms reheated steam after passing through the boiler and then enters the steam inlet of the second steam turbine. By adopting the above technical solution, by reheating the steam at the steam outlet of the first steam turbine through the boiler and then introducing it into the steam inlet of the second steam turbine, the steam temperature at the steam outlet of the first steam turbine is effectively increased, and then the steam temperature of the second steam turbine is increased.

[0038] 5. Heat storage media are provided in both the first thermal energy storage tank and the second thermal energy storage tank of the present invention. By adopting the above technical solution, it is avoided that the heat storage media leak due to flow, and at the same time, the pipeline cost for setting the flow of the heat storage media is reduced.

[0039] 6. Temperature sensors are provided on both the first heat storage tank and the second heat storage tank of the present invention; the temperature range in the first heat storage tank is: 300 - 500 °C; the temperature range in the second heat storage tank is: 200 - 350 °C; by adopting the above technical solution in this application, through the setting of the first heat storage tank and the second heat storage tank with different temperatures, energy can be released in a stepped manner, while increasing the output power of the steam turbine, reducing the irreversibility of heat exchange, and further improving the utilization efficiency of thermal energy.

[0040] 7. The steam inlet of the first heat storage tank of the present invention is connected to a first valve, and the steam outlet of the first heat storage tank is communicated with the steam inlet of the deaerator; the steam inlet of the second heat storage tank is connected to a second valve, and the steam outlet of the second heat storage tank is communicated with the steam inlet of the low-pressure heater; by adopting the above technical solution in this application, through the communication of the steam outlet of the first heat storage tank with the steam inlet of the deaerator, the heat storage in the first heat storage tank can flow back through the deaerator, reducing the extraction steam volume of the second steam turbine and increasing the rotational speed of the second steam turbine; by communicating the steam outlet of the second heat storage tank with the steam inlet of the low-pressure heater, the heat storage in the second heat storage tank can flow back through the low-pressure heater, reducing the extraction steam volume of the second steam turbine and increasing the rotational speed of the second steam turbine.

[0041] 8. The operation method of the heat storage power generation system provided by the present invention includes: when the rotational speed of the first steam turbine is greater than a first predetermined value and the rotational speed of the second steam turbine is less than a second predetermined value, open the first valve to allow a part of the main steam in the boiler to enter the first heat storage tank until the rotational speed of the first steam turbine is less than the first predetermined value, then close the first valve; when the rotational speed of the second steam turbine is greater than the first predetermined value and the rotational speed of the first steam turbine is less than the first predetermined value, open the second valve to allow a part of the reheated steam in the boiler to enter the second heat storage tank until the rotational speed of the second steam turbine is less than the first predetermined value, then close the second valve; when the rotational speeds of both the first steam turbine and the second steam turbine are greater than the first predetermined value, first open the first valve to allow a part of the main steam in the boiler to enter the first heat storage tank, and then open the second valve to allow a part of the reheated steam in the boiler to enter the second heat storage tank until the rotational speeds of both the first steam turbine and the second steam turbine are less than the first predetermined value, then close the first valve and the second valve; by adopting the above technical solution in this application, through the setting of the first heat storage tank, the steam volume entering the first steam turbine is absorbed, reducing the rotational speed of the first steam turbine; through the setting of the second heat storage tank, the steam volume entering the second steam turbine is absorbed, reducing the rotational speed of the second steam turbine; thereby coordinately regulating and stabilizing the rotational speeds of the first steam turbine and the second steam turbine, ensuring the grid frequency and the high efficiency of the unit; the modification of the unit is small, without the need to modify the unit body, and the cost is relatively low.

[0042] 9. When the rotational speed of the first steam turbine is greater than a first predetermined value and the rotational speed of the second steam turbine is less than a second predetermined value, the first valve is opened to allow part of the main steam in the boiler to enter the first heat storage tank until the rotational speed of the first steam turbine is less than the first predetermined value, at which point the first valve is closed; when the rotational speed of the second steam turbine is greater than the first predetermined value and the rotational speed of the first steam turbine is less than the first predetermined value, the second valve is opened to allow part of the reheated steam in the boiler to enter the second heat storage tank until the rotational speed of the second steam turbine is less than the first predetermined value, at which point the second valve is closed; when the rotational speeds of both the first steam turbine and the second steam turbine are greater than the first predetermined value, the first valve is first opened to allow part of the main steam in the boiler to enter the first heat storage tank, and then the second valve is opened to allow part of the reheated steam in the boiler to enter the second heat storage tank until the rotational speeds of both the first steam turbine and the second steam turbine are less than the first predetermined value, at which point the first valve and the second valve are closed; when the rotational speeds of both the first steam turbine and the second steam turbine are less than a third predetermined value, or when it is necessary to increase the system load, the fourth valve is opened to allow part of the condensed water in the condenser to enter the second heat storage tank to be heated; by adopting the above technical solution, this application absorbs the steam volume entering the first steam turbine by setting the first heat storage tank to reduce the rotational speed of the first steam turbine; releases the heat of the first heat storage tank to increase the steam volume entering the first steam turbine and increase the rotational speed of the first steam turbine; absorbs the steam volume entering the second steam turbine by setting the second heat storage tank to reduce the rotational speed of the second steam turbine; releases the heat of the second heat storage tank to increase the steam volume entering the second steam turbine and increase the rotational speed of the second steam turbine; thereby coordinately regulating and stabilizing the rotational speeds of the first steam turbine and the second steam turbine to ensure the power grid frequency and the high efficiency of the unit; the modification of the unit is small, there is no need to modify the unit body, and the cost is relatively low.

[0043] 10. When the temperature in the first heat storage tank is greater than the set temperature, the fifth valve is opened and the sixth valve is closed to allow the water flowing out of the second heat storage tank to enter the first heat storage tank for further heating into steam and then enter the deaerator; when the temperature in the first heat storage tank is less than the set temperature, the fifth valve is closed, the sixth valve and the third valve are opened to allow the water flowing out of the second heat storage tank to flow through the deaerator and the first heat storage tank in sequence and then return to the boiler; by adopting the above technical solution, this application improves the heat storage and release efficiency by using the condensed water in the condenser for heat storage and release in the second heat storage tank; by using the connection between the first heat storage tank and the second heat storage tank, the heat energy of the first heat storage tank and the second heat storage tank is reasonably utilized to improve the heat storage and release efficiency. Description of the Drawings

[0044] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0045] Figure 1 Schematic diagram of the connection structure of the thermal energy storage power generation system provided in the embodiment of the present invention;

[0046] Figure 2 Schematic diagram of the deviation comparison curve of the rotational speed of the thermal energy storage power generation system provided in the embodiment of the present invention and the power generation system without thermal energy storage with respect to the standard value;

[0047] Figure 3 Schematic diagram of the comparison of the load change rates of the thermal energy storage power generation system provided in the embodiment of the present invention and the power generation system without thermal energy storage.

[0048] Explanation of reference numerals:

[0049] 1. Boiler; 2. First steam turbine; 3. Second steam turbine; 4. Condenser; 5. Low-pressure heater; 6. Deaerator; 7. High-pressure heater; 8. First valve; 9. First thermal energy storage tank; 10. Second valve; 11. Second thermal energy storage tank; 12. Third valve; 13. Fourth valve; 14. Fifth valve; 15. Sixth valve. Specific embodiments

[0050] The following will clearly and completely describe the technical solutions of the present invention with reference to the drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0051] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention 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 should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0052] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" 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 a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0053] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0054] As Figure 1 A specific embodiment of the heat storage power generation system shown is used to coordinately regulate and stabilize the speeds of the first steam turbine and the second steam turbine, and includes: a boiler 1, a first steam turbine 2, a second steam turbine 3, a condenser 4, a low-pressure heater 5, a deaerator 6, and a high-pressure heater 7 that are connected in sequence, a first heat storage tank 9 connected to the boiler 1, and a second heat storage tank 11 connected to the condenser 4, etc.

[0055] The first steam turbine 2 and the second steam turbine 3 are not coaxially arranged. Specifically, the first steam turbine 2 is a high-pressure steam turbine, and the second steam turbine 3 is a low-pressure steam turbine; the high-pressure steam turbine is arranged at a high position, and its height is the same as the steam outlet of the boiler 1, and the low-pressure steam turbine is arranged at a low position on the ground. The steam at the steam outlet of the first steam turbine 2 forms reheated steam after passing through the boiler 1 and then enters the steam inlet of the second steam turbine 3; specifically, the boiler 1 is a coal-fired boiler; the steam inlet of the first steam turbine 2 is connected to the steam outlet of the boiler 1 (i.e., the main steam outlet) through a pipeline; specifically, the temperature of the reheated steam is greater than 520 °C and the pressure is greater than 20 bar; the temperature of the main steam is greater than 520 °C and the pressure is greater than 100 bar.

[0056] The steam outlet of the second steam turbine 3 is connected to the steam inlet of the condenser 4 through a pipeline; the condensate outlet of the condenser 4 is connected to the condensate inlet of the low-pressure heater 5 through a pipeline; the condensate outlet of the low-pressure heater 5 is connected to the condensate inlet of the deaerator 6 through a pipeline; the feed water outlet of the deaerator 6 is connected to the feed water inlet of the high-pressure heater 7 through a pipeline; the feed water outlet of the high-pressure heater 7 is connected to the feed water inlet of the boiler 1 through a pipeline.

[0057] The extraction steam outlet of the first steam turbine 2 is connected to the steam inlet of the high-pressure heater 7 through a pipeline; the first-stage extraction steam outlet of the second steam turbine 3 is connected to the steam inlet of the deaerator 6 through a pipeline; the second-stage extraction steam outlet of the second steam turbine 3 is connected to the steam inlet of the low-pressure heater 5 through a pipeline.

[0058] The first heat storage tank 9 is connected to the boiler 1 through the first valve 8. Specifically, the first valve 8 is a main steam diversion valve, and the steam inlet of the first heat storage tank 9 is connected to the main steam outlet of the boiler 1 through the first valve 8; the second heat storage tank 11 is connected to the pipeline between the second steam turbine 3 and the first steam turbine 2 through the second valve 10. Specifically, the second valve 10 is a reheated steam diversion valve, and the steam inlet of the second heat storage tank 11 is connected to the reheated steam outlet of the boiler 1 through the second valve 10; the first heat storage tank 9 is a high-temperature heat storage tank, and the second heat storage tank 11 is a medium-temperature heat storage tank. Heat storage media are provided in both the first heat storage tank 9 and the second heat storage tank 11. Specifically, the heat storage medium in the high-temperature heat storage tank is molten salt, heat-conducting oil, liquid metal, concrete, or ceramic, etc.; the heat storage medium in the medium-temperature heat storage tank is molten salt, heat-conducting oil, or organic material, etc. Temperature sensors are provided on both the first heat storage tank 9 and the second heat storage tank 11; the temperature range in the first heat storage tank 9 is: 300 - 500 °C; the temperature range in the second heat storage tank 11 is: 200 - 350 °C. Specifically, heat exchange pipelines are provided in the first heat storage tank 9 and the second heat storage tank 11 for heat exchange between steam and the heat storage medium, and between water and the heat storage medium.

[0059] The condensate outlet (i.e., the water working medium outlet) of the condenser 4 is connected to the water inlet (i.e., the water working medium inlet) of the second heat storage tank 11 through the fourth valve 13. Specifically, the fourth valve 13 is a condensate diversion valve; the water outlet (i.e., the water working medium outlet) of the second heat storage tank 11 is connected to the water inlet (i.e., the water working medium inlet) of the deaerator 6; the water outlet (i.e., the water working medium outlet) of the second heat storage tank 11 is connected to the water inlet (i.e., the water working medium inlet) of the first heat storage tank 9 through the fifth valve 14. Specifically, the fifth valve 14 is a medium-temperature heat storage tank outlet diversion valve; the water inlet (i.e., the water working medium inlet) of the first heat storage tank 9 is connected to the water outlet (i.e., the water working medium outlet) of the deaerator 6 through the third valve 12. Specifically, the third valve 12 is a high-pressure feed water diversion valve; the water outlet (i.e., the water working medium outlet) of the first heat storage tank 9 is connected to the water inlet (i.e., the feed water inlet) of the boiler 1 through the sixth valve 15. Specifically, the sixth valve 15 is a high-temperature heat storage tank outlet diversion valve. The steam inlet of the first heat storage tank 9 is connected to the first valve 8, the steam outlet (i.e., the steam outlet) of the first heat storage tank 9 is connected to the steam inlet (i.e., the steam inlet) of the deaerator 6, and the steam outlet of the first heat storage tank 9 is also connected to the water outlet of the first heat storage tank 9; the steam inlet of the second heat storage tank 11 is connected to the second valve 10, and the steam outlet (i.e., the steam outlet) of the second heat storage tank 11 is connected to the steam inlet (i.e., the steam inlet) of the low-pressure heater 5.

[0060] The present invention also provides an operation method for the thermal energy storage power generation system. When the unit's load increase demand is within 20 MW, the energy release of the first heat storage tank 9 and the second heat storage tank 11 is preferentially used to achieve the purpose of adjusting the load. To ensure the grid frequency, the rotational speeds of the first steam turbine 2 and the second steam turbine 3 during operation need to be maintained at about 3000 r / min.

[0061] When the rotational speed of the first steam turbine 2 is greater than a first predetermined value. Specifically, the first predetermined value is (3000 + a, where a is an empirical value) r / min; and when the rotational speed of the second steam turbine 3 is less than a second predetermined value. Specifically, the second predetermined value is (3000 - a) r / min; open the first valve 8 to allow some of the main steam in the boiler 1 to enter the first heat storage tank 9 until the rotational speed of the first steam turbine 2 is less than the first predetermined value, then close the first valve 8.

[0062] When the rotational speed of the second steam turbine 3 is greater than the first predetermined value and the rotational speed of the first steam turbine 2 is less than the first predetermined value, open the second valve 10 to allow some of the reheated steam in the boiler 1 to enter the second heat storage tank 11 until the rotational speed of the second steam turbine 3 is less than the first predetermined value, then close the second valve 10.

[0063] When the rotational speeds of both the first steam turbine 2 and the second steam turbine 3 are greater than the first predetermined value, first open the first valve 8 to allow some of the main steam in the boiler 1 to enter the first heat storage tank 9, and then open the second valve 10 to allow some of the reheated steam in the boiler 1 to enter the second heat storage tank 11 until the rotational speeds of both the first steam turbine 2 and the second steam turbine 3 are less than the first predetermined value, then close the first valve 8 and the second valve 10.

[0064] When the rotational speeds of both the first steam turbine 2 and the second steam turbine 3 are less than a third predetermined value. Specifically, the third predetermined value is 3000 r / min; or when it is necessary to quickly increase the system load, open the fourth valve 13 to allow some of the condensate water in the condenser 4 to enter the second heat storage tank 11 to be heated.

[0065] When the temperature in the first heat storage tank 9 is greater than the set temperature. Specifically, the set temperature is 400 °C; open the fifth valve 14 and close the sixth valve 15 to allow the water flowing out of the second heat storage tank 11 to enter the first heat storage tank 9 to be further heated into steam and enter the deaerator 6.

[0066] When the temperature in the first heat storage tank 9 is less than the set temperature, close the fifth valve 14, open the sixth valve 15 and the third valve 12 to allow the water flowing out of the second heat storage tank 11 to flow through the deaerator 6 and the first heat storage tank 9 in sequence and return to the boiler 1.

[0067] As Figure 2The figure shows a schematic diagram of the deviation comparison curve of the rotational speed between the thermal energy storage power generation system and the power generation system without thermal energy storage provided in the embodiment of the present invention. Among them, the vertical coordinate is the deviation of the rotational speed from the standard value, expressed as a percentage; taking a 660MW ultra-supercritical coal-fired unit as an example, the standard value is set to 5r / min, that is, the horizontal line where the vertical coordinate is 0. From Figure 2 it can be seen that the rotational speed fluctuation of the thermal energy storage power generation system of the present invention is significantly smaller than that of the power generation system without thermal energy storage, and the rotational speed of the thermal energy storage power generation system described in this application is closer to the stable standard value.

[0068] As Figure 3 shown is a schematic diagram of the comparison of the load change rate between the thermal energy storage power generation system and the power generation system without thermal energy storage provided in the embodiment of the present invention. Among them, the load change rate is defined as the change amount of the unit output power of the unit in unit time, and the change amount of the power can be expressed as a percentage of the rated load. Assuming the rated load is Pe0, in Figure 3 it, the unit of the vertical coordinate is %Pe0 / min, that is, % rated load per minute. From Figure 3 it can be seen that the load change rate of the power generation system without thermal energy storage is 1.5% rated load per minute, and the load change rate of the thermal energy storage power generation system of the present invention is 2.5% rated load per minute; the load change rate of the thermal energy storage power generation system described in this application is significantly higher than that of the power generation system without thermal energy storage, that is, the response speed of the thermal energy storage power generation system described in this application is faster.

[0069] The working principle process of the thermal energy storage power generation system described in this application is briefly described as follows: The main steam of the boiler 1 flows into the first steam turbine 2; the steam after being utilized by the first steam turbine 2 enters the boiler 1 for reheating to form reheated steam and is input into the second steam turbine 3; the steam after being utilized by the second steam turbine 3 enters the condenser 4 and condenses into condensate; the condensate flows into the low-pressure heater 5, and the low-pressure heater 5 uses the extraction steam of the second steam turbine 3 to heat the condensate to form preliminarily preheated water; the preliminarily preheated water flows into the deaerator 6, and the deaerator 6 uses the extraction steam of the second steam turbine 3 to remove oxygen; the water after removing oxygen flows into the high-pressure heater 7, and the high-pressure heater 7 uses the extraction steam of the first steam turbine 2 to heat the water; the heated water flows into the boiler 1 for recycling.

[0070] When thermal energy storage is required, open the first valve 8, and part of the main steam of the boiler 1 flows into the first thermal energy storage tank 9, and the heat is exchanged to the thermal energy storage medium, and the rotational speed of the first steam turbine 2 decreases; open the second valve 10, and part of the reheated steam flows into the second thermal energy storage tank 11, and the heat is exchanged to the thermal energy storage medium, and the rotational speed of the second steam turbine 3 decreases.

[0071] When heat release is required, the steam after heat exchange with the heat storage medium in the first heat storage tank 9 flows into the deaerator 6, reducing the extraction steam amount of the deaerator 6 for the second steam turbine 3, and the rotational speed of the second steam turbine 3 increases; the steam after heat exchange with the heat storage medium in the second heat storage tank 11 flows into the low-pressure heater 5, reducing the extraction steam amount of the low-pressure heater 5 for the second steam turbine 3, and the rotational speed of the second steam turbine 3 increases.

[0072] Meanwhile, the condensate water condensed in the condenser 4 flows into the second heat storage tank 11 and is heated through heat exchange with the heat storage medium. The heated water and the generated steam can flow to the deaerator 6 for recycling. At the same time, the steam can also flow into the subsequent high-pressure heater 7, reducing the extraction steam amount of the high-pressure heater 7 for the first steam turbine 2, and the rotational speed of the first steam turbine 2 increases; the heated water can also enter the first heat storage tank 9 and be reheated through heat exchange with the heat storage medium; the water after deaeration in the deaerator 6 can also flow into the first heat storage tank 9 and be heated through heat exchange with the heat storage medium; the steam after heat exchange and heating in the first heat storage tank 9 can be transported to the deaerator 6. At the same time, the steam can also flow into the subsequent high-pressure heater 7, reducing the extraction steam amount of the high-pressure heater 7 for the first steam turbine 2, and the rotational speed of the first steam turbine 2 increases; it can also be recycled to the boiler 1 for recycling, increasing the main steam amount, and the rotational speed of the first steam turbine 2 increases.

[0073] As an alternative embodiment, heat exchange pipelines are arranged in the first heat storage tank 9 and the second heat storage tank 11, and it is replaced by encapsulating the heat storage medium into capsules for heat exchange.

[0074] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A thermal energy storage power generation system, characterized in that, it includes: a boiler (1), a first steam turbine (2) and a second steam turbine (3) connected in sequence, and the first steam turbine (2) and the second steam turbine (3) are not coaxially arranged; a first heat storage tank (9), which is connected to the boiler (1) through a first valve (8); a second heat storage tank (11), which is connected to the pipeline between the second steam turbine (3) and the first steam turbine (2) through a second valve (10); It further includes: a condenser (4), a low-pressure heater (5), a deaerator (6) and a high-pressure heater (7) connected in sequence; the condensate outlet of the condenser (4) is communicated with the water inlet of the second heat storage tank (11) through a fourth valve (13); the water outlet of the second heat storage tank (11) is communicated with the water inlet of the deaerator (6); the water outlet of the second heat storage tank (11) is communicated with the water inlet of the first heat storage tank (9) through a fifth valve (14); the water inlet of the first heat storage tank (9) is communicated with the water outlet of the deaerator (6) through a third valve (12); the water outlet of the first heat storage tank (9) is communicated with the water inlet of the boiler (1) through a sixth valve (15); the steam inlet of the first heat storage tank (9) is connected to the first valve (8), and the steam outlet of the first heat storage tank (9) is communicated with the steam inlet of the deaerator (6); the steam inlet of the second heat storage tank (11) is connected to the second valve (10), and the steam outlet of the second heat storage tank (11) is communicated with the steam inlet of the low-pressure heater (5).

2. The thermal energy storage power generation system according to claim 1, characterized in that, the steam at the steam outlet of the first steam turbine (2) forms reheated steam after passing through the boiler (1), and then enters the steam inlet of the second steam turbine (3).

3. The thermal energy storage power generation system according to claim 1, characterized in that, heat storage media are provided in both the first heat storage tank (9) and the second heat storage tank (11).

4. The thermal energy storage power generation system according to claim 1, characterized in that, temperature sensors are provided on both the first heat storage tank (9) and the second heat storage tank (11); the temperature range in the first heat storage tank (9) is: 300 - 500 °C; the temperature range in the second heat storage tank (11) is: 200 - 350 °C.

5. An operation method of the thermal energy storage power generation system according to claim 1, characterized in that, it includes: when the rotational speed of the first steam turbine (2) is greater than a first predetermined value and the rotational speed of the second steam turbine (3) is less than a second predetermined value, open the first valve (8) so that part of the main steam in the boiler (1) enters the first heat storage tank (9) until the rotational speed of the first steam turbine (2) is less than the first predetermined value, then close the first valve (8); when the rotational speed of the second steam turbine (3) is greater than a first predetermined value and the rotational speed of the first steam turbine (2) is less than a first predetermined value, open the second valve (10) so that part of the reheated steam in the boiler (1) enters the second heat storage tank (11) until the rotational speed of the second steam turbine (3) is less than the first predetermined value, then close the second valve (10); When the rotational speeds of both the first steam turbine (2) and the second steam turbine (3) are greater than the first predetermined value, first open the first valve (8) to allow part of the main steam in the boiler (1) to enter the first heat storage tank (9), and then open the second valve (10) to allow part of the reheated steam in the boiler (1) to enter the second heat storage tank (11), until the rotational speeds of both the first steam turbine (2) and the second steam turbine (3) are less than the first predetermined value, then close the first valve (8) and the second valve (10).

6. A method for operating a heat storage power generation system according to any one of claims 2-4, characterized in that, when the rotational speed of the first steam turbine (2) is greater than the first predetermined value and the rotational speed of the second steam turbine (3) is less than the second predetermined value, open the first valve (8) to allow part of the main steam in the boiler (1) to enter the first heat storage tank (9), until the rotational speed of the first steam turbine (2) is less than the first predetermined value, then close the first valve (8); when the rotational speed of the second steam turbine (3) is greater than the first predetermined value and the rotational speed of the first steam turbine (2) is less than the first predetermined value, open the second valve (10) to allow part of the reheated steam in the boiler (1) to enter the second heat storage tank (11), until the rotational speed of the second steam turbine (3) is less than the first predetermined value, then close the second valve (10); when the rotational speeds of both the first steam turbine (2) and the second steam turbine (3) are greater than the first predetermined value, first open the first valve (8) to allow part of the main steam in the boiler (1) to enter the first heat storage tank (9), and then open the second valve (10) to allow part of the reheated steam in the boiler (1) to enter the second heat storage tank (11), until the rotational speeds of both the first steam turbine (2) and the second steam turbine (3) are less than the first predetermined value, then close the first valve (8) and the second valve (10); when the rotational speeds of both the first steam turbine (2) and the second steam turbine (3) are less than the third predetermined value, or when it is necessary to increase the system load, open the fourth valve (13) to allow part of the condensate water in the condenser (4) to enter the second heat storage tank (11) to be heated.

7. The method for operating a heat storage power generation system according to claim 6, characterized in that, when the temperature in the first heat storage tank (9) is greater than the set temperature, open the fifth valve (14) and close the sixth valve (15) to allow the water flowing out of the second heat storage tank (11) to enter the first heat storage tank (9) to be further heated into steam and enter the deaerator (6); when the temperature in the first heat storage tank (9) is less than the set temperature, close the fifth valve (14), open the sixth valve (15) and the third valve (12) to allow the water flowing out of the second heat storage tank (11) to flow through the deaerator (6) and the first heat storage tank (9) in sequence and return to the boiler (1).

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