Elastic regenerative system and method for improving variable load rate of coal-fired generator set

Abstract

The application provides a flexible regenerative system and method for improving the variable load rate of a coal-fired power generating unit, and belongs to the field of heat storage peak regulation. The system comprises a steam turbine, a generator, a condenser, a steam extraction pipeline, an exhaust steam pipeline, a first regenerative unit, a heat storage tank, a sprayer, a spray water pipeline and a boiler. The generator is connected to the steam turbine, the inlet of the steam turbine is connected to the outlet of the boiler, the first outlet of the steam turbine is connected to the first inlet of the first regenerative unit through the steam extraction pipeline, the condenser is arranged between the second outlet of the steam turbine and the second inlet of the first regenerative unit, and the outlet of the first regenerative unit is connected to the inlet of the boiler. The sprayer is arranged in the heat storage tank, the spray water pipeline is connected to the sprayer, the inlet of the heat storage tank is connected to the first outlet of the steam turbine, and the first outlet of the heat storage tank is connected to the first inlet of the first regenerative unit. Through the system provided by the application, the deep peak regulation capacity and the rapid variable load capacity of the steam turbine generator unit can be further improved.

Description

Technical Field

[0001] This invention relates to the field of thermal energy storage and peak shaving technology, specifically to an elastic regenerative system and a method for improving the load change rate of coal-fired power generating units. Background Technology

[0002] Currently, coal-fired power generating units primarily control their load during load increases and decreases by adjusting the amount of fuel fed into the boiler and the opening of the main steam valve on the turbine side, thereby meeting the unit's load response rate requirements. This adjustment method is often accompanied by significant fluctuations in the unit's main steam parameters and reduced economic efficiency. Furthermore, the large inertia inherent in the boiler system itself limits the unit's ability to rapidly change load, resulting in peak-shaving rates of approximately 1.5% of rated load per minute for boilers of 300MW and above at 50% to 100% rated load, and generally less than 1% of rated load per minute at a deep peak-shaving state of around 30% load. However, with the increasing proportion of renewable energy sources, a load change rate of approximately 1% to 1.5% is no longer sufficient to meet the requirements for rapid peak shaving.

[0003] In summary, improving the load change rate of coal-fired power generating units is of great significance for ensuring the safe and stable operation of the power system. Summary of the Invention

[0004] To address the technical problem that the load change rate of existing coal-fired power generating units cannot meet the requirements of rapid peak shaving, this invention provides an elastic regenerative system and method for improving the load change rate of coal-fired power generating units. The system and method can flexibly and quickly adjust the load change rate of coal-fired power generating units, thereby improving the stability of the power system and the quality of power supply.

[0005] To achieve the above objectives, the present invention provides an elastic regenerative system for improving the load change rate of a coal-fired power generation unit. The system includes: a steam turbine, a generator, a condenser, an extraction steam pipe, an exhaust steam pipe, a first regenerative unit, a heat storage unit, and a boiler. The generator is connected to the steam turbine, the inlet of the steam turbine is connected to the outlet of the boiler, the first outlet of the steam turbine is connected to the first inlet of the first regenerative unit via the extraction steam pipe, the second outlet of the steam turbine is connected to the inlet of the condenser via the exhaust steam pipe, the outlet of the condenser is connected to the second inlet of the first regenerative unit, and the outlet of the first regenerative unit is connected to the inlet of the boiler. The first regenerative unit consists of at least one heater. The heat storage unit includes: a heat storage tank, a sprayer, and a spray water pipe. The sprayer is installed inside the heat storage tank, the spray water pipe is connected to the sprayer via the first inlet of the heat storage tank, the second inlet of the heat storage tank is connected to the first outlet of the steam turbine, and the first outlet of the heat storage tank is connected to the first inlet of the first regenerative unit.

[0006] In an exemplary embodiment of the present invention, the elastic regenerative system may further include: a second regenerative unit, the second regenerative unit including: a heat exchanger, a water supply pipe and a drain pipe; the heat source inlet of the heat exchanger is connected to the second outlet of the heat storage tank, the cold source inlet of the heat exchanger is connected to the outlet of the water supply pipe, the heat source outlet of the heat exchanger is connected to the inlet of the boiler, and the cold source outlet of the heat exchanger is connected to the inlet of the drain pipe.

[0007] In an exemplary embodiment of the present invention, the steam turbine is composed of multiple cylinders with different pressure levels. The number of first regenerative units, second regenerative units and / or heat storage units can be at least one. A single first regenerative unit and / or heat storage unit is connected to at least one cylinder in the steam turbine, and a single second regenerative unit is connected to at least one heat storage unit.

[0008] In an exemplary embodiment of the present invention, a deaerator and a pump set may be provided between the condenser and the first regenerative unit.

[0009] In an exemplary embodiment of the present invention, a check valve may be provided at the first outlet of the steam turbine.

[0010] In one exemplary embodiment of the present invention, the inlet of the condensate drain pipe and / or the water supply pipe may be connected to the outlet of the condenser.

[0011] In an exemplary embodiment of the present invention, the inlet of the spray water pipe may be connected to the cold source outlet of the unit reheater.

[0012] Another aspect of the present invention provides an elastic regenerative method for improving the load change rate of a coal-fired power generating unit. The elastic regenerative method is implemented through the elastic regenerative system described above, comprising: a normal operation phase, a load reduction phase, and a load increase phase. During the normal operation phase, a portion of the heat energy from the turbine extraction steam is used to heat the condensate formed by the turbine exhaust steam in a first regenerative unit, and the heated condensate is then used as boiler feedwater. During the load reduction phase, a portion of the turbine extraction steam is pre-stored in a heat storage tank, and the temperature inside the heat storage tank is maintained at the saturation temperature corresponding to the extraction steam pressure in the extraction steam pipeline by spraying water into the heat storage tank. During the load increase phase, a portion of the working fluid stored in the heat storage tank flows into the first regenerative unit by gravity due to the pressure difference between the working fluid and the liquid formed by the condensation of the working fluid in the first regenerative unit, and participates in the process of heating the condensate using the turbine extraction steam in the first regenerative unit. The working fluid is a mixture formed by the extraction steam and the sprayed water.

[0013] In another exemplary embodiment of the present invention, the elastic regenerative method may further include: during the load increase phase, transporting another portion of the working fluid stored in the heat storage tank to the second regenerative unit to exchange heat with cold water, and transporting the heat-exchanged hot water to the boiler as boiler feedwater, and transporting the heat-exchanged condensate to the first regenerative unit as condensate.

[0014] In another exemplary embodiment of the present invention, the water temperature at the outlet of the first regenerating unit may be the same as the water temperature at the heat source outlet of the second regenerating unit.

[0015] The present invention has at least the following technical effects through the technical solution provided by the present invention:

[0016] (1) The elastic regenerative system of the present invention can store the extracted steam heat energy in the steam turbine power generation system through the heat storage tank when the coal-fired power generation unit is under high load, and release the extracted steam heat energy stored in the heat storage tank to heat the boiler feedwater when the coal-fired power generation unit is under low load, thereby improving the load change rate of the coal-fired power generation unit and improving the stability and power supply quality of the power system.

[0017] (2) The design of the heat storage tank in this invention makes the storage and release of steam heat more efficient, reduces energy loss, and improves the economy of the elastic regenerative system.

[0018] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a schematic diagram of the structure of an elastic regenerative system for improving the variable load rate of a coal-fired power generation unit, provided in an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of another elastic regenerative system for improving the variable load rate of a coal-fired power generation unit, provided in an embodiment of the present invention.

[0022] Explanation of reference numerals in the attached figures

[0023] 11-Water supply bypass inlet, 12-Water supply bypass, 13-Water supply bypass heater, 14-High-pressure thermal storage tank power supply pipeline, 15-High-pressure thermal storage tank power supply pipeline regulating valve assembly, 16-High-pressure thermal storage tank, 17-High-pressure sprayer, 18-High-pressure spray regulating valve assembly, 19-High-pressure spray water supply pipeline, 110-Water supply bypass regulating valve assembly, 111-Water supply bypass intake, 112-High-pressure thermal storage tank storage pipe 113-High-pressure thermal accumulator energy storage pipeline regulating valve assembly; 114-High-pressure check valve; 115-High-pressure power supply pipeline drain; 116-Steam turbine high-pressure extraction pipe tee; 21-Condensate bypass inlet; 22-Condensate bypass; 23-Condensate bypass heater; 24-Low-pressure thermal accumulator energy supply pipeline; 25-Low-pressure thermal accumulator energy supply pipeline regulating valve assembly; 26-Low-pressure thermal accumulator; 27-Low-pressure sprayer. 28-Low-pressure spray water regulating valve assembly; 29-Low-pressure spray water pipeline; 210-Condensate bypass regulating valve assembly; 211-Condensate bypass intake; 212-Low-pressure thermal storage tank energy storage pipeline; 213-Low-pressure thermal storage tank energy storage pipeline regulating valve assembly; 214-Low-pressure check valve; 215-Low-pressure power supply pipeline drain; 216-Steam turbine low-pressure extraction pipe tee; 31-Boiler; 32-High-pressure steam pipeline; 33- 34-High-pressure steam cylinder of steam turbine, 35-Low-pressure steam pipeline, 36-Exhaust steam pipeline, 37-Condenser, 38-Condensate pump, 39-Condensate pipeline, 310-Low-pressure heater group, 311-Low-pressure extraction steam pipeline, 312-Deaerator, 313-Feed water pump, 314-Feed water pipeline, 315-High-pressure extraction steam pipeline, 316-High-pressure heater group, 317-Generator. Detailed Implementation

[0024] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0026] In this invention, terms such as "first" and "second" are used merely for ease of description and distinction, and should not be construed as indicating or implying relative importance.

[0027] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integrated connection; they can refer to a direct connection or an indirect connection; they can refer to a wired connection or a wireless connection. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] This invention provides an elastic regenerative system for improving the load change rate of a coal-fired power generating unit. The elastic regenerative system comprises a coal-fired power generation system and a thermal storage and peak-shaving subsystem. The coal-fired power generation system is used to generate electricity from coal and may include structures such as a steam turbine, generator, condenser, extraction steam pipe, exhaust steam pipe, first regenerative unit, and boiler. The thermal storage and peak-shaving subsystem is used to adjust the load capacity of the coal-fired power generating unit and may include a thermal storage unit.

[0030] Specifically, in the entire regenerative thermal system, the generator is connected to the steam turbine, the turbine inlet is connected to the boiler outlet, the first outlet of the steam turbine is connected to the first inlet of the first regenerative unit via an extraction steam pipe, the second outlet of the steam turbine is connected to the condenser inlet via an exhaust steam pipe, the condenser outlet is connected to the second inlet of the first regenerative unit, and the outlet of the first regenerative unit is connected to the boiler inlet. The function of the first regenerative unit is to use the heat energy of the steam extracted from the turbine to heat the condensate output from the condenser. The first regenerative unit can be configured as a heater, and the number of heaters can be one or more, depending on the regenerative requirements of the entire regenerative thermal system. In this way, while using the high-temperature and high-pressure steam generated by the boiler to drive the turbine to rotate and drive the generator to generate electricity, the condensate formed by the steam turbine exhaust steam can be recovered, and a portion of the heat energy of the steam extracted from the turbine can be used to heat the condensate. The heated condensate can then be used as boiler feedwater to regenerate high-temperature and high-pressure steam for subsequent power generation.

[0031] The function of the thermal storage unit is to store a portion of the turbine extraction steam when the coal-fired power unit is under high load, and to release the pre-stored turbine extraction steam for condensate heating when the coal-fired power unit is under low load. The thermal storage unit may include a heat storage tank, a sprayer, and spray water pipes. The sprayer is installed inside the heat storage tank, and the spray water pipes are connected to the sprayer through the first inlet of the heat storage tank. The first outlet of the turbine is connected to the second inlet of the heat storage tank through the extraction steam pipe, and the first outlet of the heat storage tank is connected to the first inlet of the first regenerative unit. Thus, when the coal-fired power unit needs to reduce load, the turbine extraction steam enters the heat storage tank through the extraction steam pipe, and water is sprayed into the heat storage tank through the sprayer to cool it down, maintaining the temperature inside the heat storage tank at the saturation temperature corresponding to the extraction steam pressure in the extraction steam pipe. t1. As the extracted steam continuously condenses into water, a pressure difference is created within the heat storage tank. Therefore, the extracted steam from the extraction pipeline can continuously enter the heat storage tank until it reaches its maximum storage capacity. When the coal-fired power generation unit needs to increase its load, the working fluid stored in the heat storage tank (i.e., the mixture formed by the extracted steam and sprayed water) can flow into the first regenerative unit by gravity due to the pressure difference between it and the liquid formed by the condensation of the working fluid in the first regenerative unit. In the first regenerative unit, it heats the condensate output from the condenser.

[0032] Furthermore, in one possible implementation, the elastic regenerative system may further include a second regenerative unit. The second regenerative unit recovers the heat energy from the steam extracted from the heat storage tank for heating boiler feedwater. The second regenerative unit may include a heat exchanger, a water supply pipeline, and a drain pipeline. The heat source inlet of the heat exchanger is connected to the second outlet of the heat storage tank, the cold source inlet of the heat exchanger is connected to the outlet of the water supply pipeline, the heat source outlet of the heat exchanger is connected to the boiler inlet, and the cold source outlet of the heat exchanger is connected to the inlet of the drain pipeline. Thus, when the coal-fired power generation unit needs to increase its load, the steam extracted from the heat storage tank can not only flow by gravity into the first regenerative unit to participate in condensate heating, but also enter the heat exchanger to exchange heat with the bypass condensate. The hot water obtained through both methods can be supplied to the boiler as boiler feedwater, thereby rapidly reducing the amount of steam extracted from the turbine.

[0033] Furthermore, in one possible implementation, the steam turbine comprises multiple cylinders with different pressure levels, and the number of first regenerative units, second regenerative units, and heat storage units can all be one or more. A single first regenerative unit can be connected to at least one cylinder within the steam turbine, a single heat storage unit can be connected to at least one cylinder within the steam turbine, and a single second regenerative unit can be connected to at least one heat storage unit. In other words, the first regenerative unit, used in conjunction with multiple cylinders within the steam turbine, can be arranged in a one-to-one or one-to-many manner; similarly, the heat storage units, also used in conjunction with multiple cylinders within the steam turbine, can be arranged in a one-to-one or one-to-many manner; and the second regenerative unit, used in conjunction with the heat storage units, can be arranged in a one-to-one or one-to-many manner.

[0034] Furthermore, in one possible implementation, a deaerator and a pump set can be installed between the condenser and the first regenerative unit. The deaerator is used to remove oxygen from the condensate to prevent it from corroding and damaging the turbine and related equipment. The pump set is used to increase the condensate pressure.

[0035] Furthermore, in one possible implementation, a check valve is provided at the first outlet of the steam turbine to prevent the extracted steam in the extraction pipe from flowing back into the steam turbine.

[0036] Furthermore, in one possible implementation, the inlet of the condensate drain pipe and / or water supply pipe can be connected to the outlet of the condenser. When the coal-fired power generating unit needs to increase its load, the condensate supplied by the condenser can enter the heat exchanger through the water supply pipe to exchange heat with the extracted steam released from the heat storage tank. The condensate after heat exchange is used as boiler feedwater, and the drain water after heat exchange can flow into the first regenerative unit through the drain pipe to participate in the heating process of other condensates. In this way, the condensate can be recycled, improving energy utilization efficiency and reducing energy consumption and emissions of coal-fired power plants.

[0037] Furthermore, in one possible implementation, the inlet of the spray water pipe can be connected to the cold source outlet of the unit's reheater.

[0038] This invention also provides an elastic regenerative method for increasing the load change rate of a coal-fired power generation unit. This elastic regenerative method is implemented through the elastic regenerative system for increasing the load change rate of a coal-fired power generation unit described in the above embodiments, and includes three stages: normal operation stage, load reduction stage, and load increase stage.

[0039] Specifically, during normal operation, a portion of the heat energy from the steam extracted from the turbine is used to heat the condensate formed by the steam exhaust from the turbine in the first regenerative unit, and the heated condensate is then used as boiler feedwater to the boiler.

[0040] During the load reduction phase, a portion of the turbine extraction steam is pre-stored in a heat storage tank, and the temperature inside the heat storage tank is maintained at the saturation temperature corresponding to the extraction steam pressure in the extraction pipeline by spraying water into the heat storage tank.

[0041] During the load ramp-up phase, a portion of the working fluid stored in the heat storage tank (i.e., the mixture formed by steam extraction and water spray) flows into the first regenerative unit by gravity due to the pressure difference between it and the liquid formed by the condensation of the working fluid in the first regenerative unit, and participates in the process of heating condensate by steam extraction from the turbine in the first regenerative unit.

[0042] Furthermore, in one possible implementation, the elastic regenerative method further includes: during the load increase phase, while releasing a portion of the working fluid in the heat storage tank to heat the boiler feedwater, transporting another portion of the working fluid stored in the heat storage tank to the second regenerative unit to exchange heat with cold water, and transporting the heat-exchanged hot water to the boiler as boiler feedwater, and transporting the heat-exchanged condensate to the first regenerative unit as condensate.

[0043] Furthermore, in one possible implementation, the water temperature at the outlet of the first regenerating unit can be the same as the water temperature at the heat source outlet of the second regenerating unit.

[0044] To better understand the exemplary embodiments of the present invention described above, they will be further described below in conjunction with specific examples and accompanying drawings.

[0045] Example 1

[0046] like Figure 1 As shown, a flexible regenerative system for improving the load change rate of a coal-fired power generation unit consists of a high-pressure storage / heat supply flexible regulation section, a low-pressure storage / heat supply flexible regulation section, and the original coal-fired power generation unit section. The high-pressure storage / heat supply flexible regulation section comprises a high-pressure storage tank, a feedwater bypass heater, and corresponding pipes, valves, tees, and other equipment. The low-pressure storage / heat supply flexible regulation section comprises a high-pressure storage tank, a condensate bypass heater, and corresponding pipes, valves, tees, and other equipment. The original coal-fired power generation unit section can be any type of coal-fired power generation unit, with typical components including a boiler, turbine, generator, condenser, heater, regenerative pipes, pumps, etc.

[0047] Specifically, in the high-pressure heat storage / supply flexible regulation section, the high-pressure heat storage tank 16 is connected to the turbine high-pressure extraction steam pipe tee 116 via the high-pressure heat storage tank storage pipe 112. The other end of the turbine high-pressure extraction steam pipe tee 116 is connected to the high-pressure extraction steam pipe 315 of the turbine high-pressure cylinder 33. To prevent extraction steam from flowing back into the turbine, a high-pressure check valve 114 is added to the high-pressure extraction steam pipe 315. The high-pressure heat storage tank storage pipe 112 is equipped with a high-pressure heat storage tank storage pipe regulating valve group 113, which includes any number of shut-off valves, regulating valves, and pressure reducing valves.

[0048] A high-pressure sprayer 17 is installed inside the high-pressure heat storage tank 16, and the high-pressure sprayer 17 is connected to the spray water through a high-pressure spray water supply pipe 19. A high-pressure spray regulating valve group 18 is installed on the high-pressure spray water supply pipe 19, which includes any number of shut-off valves, regulating valves, and pressure reducing valves. The spray water on the high-pressure spray water supply pipe 19 is preferably reheat desuperheating water or superheated desuperheating water from the unit, matched according to the pressure of the high-pressure heat storage tank 16.

[0049] In addition, the high-pressure heat storage tank 16 is connected to the feedwater bypass heater 13 via the high-pressure heat storage tank power supply pipeline 14. The feedwater bypass heater is preferably a plate heat exchanger, and the heat exchange medium is steam from the high-pressure heat storage tank 16 and water from the feedwater bypass 12. The high-pressure heat storage tank power supply pipeline 14 is equipped with a high-pressure heat storage tank power supply pipeline regulating valve assembly 15, which includes any number of shut-off valves, regulating valves, and pressure reducing valves.

[0050] After the steam in the high-pressure heat storage tank 16 transfers heat to the water in the feedwater bypass heater 13, it enters the deaerator 312 through the high-pressure power supply pipeline drain 115.

[0051] The water in the feedwater bypass 12 originates from the bypass feedwater intake (tee) 111 at the outlet of the feedwater pump 313. After being heated by steam in the high-pressure heat storage tank 16, the water enters the bypass feedwater inlet (tee) 11 and finally enters the boiler 31. The feedwater bypass 12 is equipped with a feedwater bypass regulating valve group 110, which includes any number of shut-off valves, regulating valves, and pressure reducing valves.

[0052] In the low-pressure storage / heat supply flexible regulation section, the low-pressure heat storage tank 26 is connected to the turbine low-pressure extraction steam pipe tee 216 via the low-pressure heat storage tank storage pipe 212. The other end of the turbine low-pressure extraction steam pipe tee 216 is connected to the low-pressure extraction steam pipe 311 of the turbine low-pressure cylinder 35. To prevent extraction steam from flowing back into the turbine, a low-pressure check valve 214 is added to the low-pressure extraction steam pipe 311. The low-pressure heat storage tank storage pipe 212 is equipped with a low-pressure heat storage tank storage pipe regulating valve group 213, which includes any number of shut-off valves, regulating valves, and pressure reducing valves.

[0053] The low-pressure heat storage tank 26 includes a low-pressure sprayer 27, which is connected to spray water via a low-pressure spray water pipe 29. A low-pressure spray water regulating valve assembly 28 is installed on the low-pressure spray water pipe 29, which includes any number of shut-off valves, regulating valves, and pressure reducing valves. The spray water on the low-pressure spray water pipe 29 is preferably condensate from the outlet of the condenser 37.

[0054] In addition, the low-pressure heat storage tank 26 is connected to the condensate bypass heater 23 via the low-pressure heat storage tank power supply pipeline 24. The condensate bypass heater is preferably a plate heat exchanger, and the heat exchange medium is steam from the low-pressure heat storage tank 26 and water from the condensate bypass 22. The low-pressure heat storage tank power supply pipeline 24 is equipped with a low-pressure heat storage tank power supply pipeline regulating valve assembly 25, which includes any number of shut-off valves, regulating valves, and pressure reducing valves.

[0055] The steam from the low-pressure heat storage tank 26 transfers its heat to the water in the condensate bypass heater 23, and then enters the condenser 37 through the low-pressure power supply pipeline drain 215.

[0056] The water in the condensate bypass 22 originates from the condensate inlet (tee) 211 at the outlet of the condensate pump 37. After being heated by steam in the low-pressure heat storage tank 26, the water enters the condensate manifold (tee) 21 and finally flows into the deaerator 312. The condensate bypass 22 is equipped with a condensate bypass regulating valve assembly 210, which includes any number of shut-off valves, regulating valves, and pressure reducing valves.

[0057] In the original coal-fired power generation unit section, the steam turbine includes a high-pressure cylinder 33 and a low-pressure cylinder 35. The high-pressure cylinder 33 is the high-pressure part of the steam turbine system and can be the ultra-high-pressure cylinder or high-pressure cylinder of the coal-fired power generation unit; the low-pressure cylinder 35 is the low-pressure part of the steam turbine system and can be the intermediate-pressure cylinder or low-pressure cylinder of the coal-fired power generation unit.

[0058] The high-pressure heater assembly 316 is arranged on the feedwater pipeline 314 and connected to the high-pressure cylinder 33 of the steam turbine via the high-pressure extraction steam pipeline 315. The low-pressure heater assembly 310 is arranged on the condensate pipeline 39 and connected to the low-pressure cylinder 35 of the steam turbine via the low-pressure extraction steam pipeline 311.

[0059] High-pressure steam pipe 32 connects boiler 31 and turbine high-pressure cylinder 33. Low-pressure steam pipe 34 connects turbine high-pressure cylinder 33 and turbine low-pressure cylinder 35. Exhaust pipe 36 connects turbine low-pressure cylinder 35 and condenser 37. Condensate pipe 39 connects condenser 37 and deaerator 312. Feedwater pipe 314 connects deaerator 312 and boiler 31.

[0060] Condensate pump 38 is located between condenser 37 and low-pressure heater group 310. Feedwater pump 313 is located between deaerator 312 and high-pressure heater group 316.

[0061] The principle behind the flexible regenerative system in this example for regulating the load change rate of a coal-fired power generator unit is as follows: The high-pressure and low-pressure flexible storage / heat supply sections are used to rapidly adjust the turbine's steam extraction rate, thereby changing the turbine's output and thus adjusting the load. Specifically, when the unit needs to reduce load, the steam extraction from the turbine is increased using the heat storage tank and stored there, thus increasing the unit's load reduction rate. When the unit needs to increase load, steam is released from the heat storage tank and simultaneously enters the first and second regenerative units, reducing the turbine's steam extraction and thus increasing the unit's load increase rate.

[0062] When it is necessary to increase the load reduction rate of coal-fired units, the specific process of using the elastic regenerative system in this example for heat storage and peak shaving is as follows.

[0063] Step A1: When the coal-fired unit is running at high load, a load reduction command is received.

[0064] Step A2: Charge the high-pressure storage / heat supply flexible adjustment section, specifically: Open the regulating valve group 113 of the high-pressure heat storage tank's energy storage pipeline, and store the extracted steam in the high-pressure heat storage tank 16 through the turbine high-pressure extraction steam pipe tee 116. Simultaneously with the extraction steam entering the high-pressure heat storage tank 16, open the high-pressure spray regulating valve group 18 to spray water into the high-pressure heat storage tank 16 for cooling, maintaining the temperature inside the high-pressure heat storage tank 16 at the saturation temperature corresponding to the extraction steam pressure in the high-pressure extraction steam pipeline 315. t1. As the extracted steam continuously condenses into water, a pressure difference is formed inside the high-pressure heat storage tank 16. Therefore, the extracted steam in the turbine high-pressure extraction pipe tee 116 can continuously enter the high-pressure heat storage tank 16 until the high-pressure heat storage tank 16 reaches its maximum heat storage volume.

[0065] Step A3: Charge the low-pressure storage / heating flexible adjustment section, specifically: Open the regulating valve group 213 of the low-pressure heat storage tank's energy storage pipeline, and store the extracted steam in the low-pressure heat storage tank 26 through the turbine low-pressure extraction steam pipe tee 216. Simultaneously with the extraction steam entering the low-pressure heat storage tank 26, open the low-pressure spray water regulating valve group 28 to spray water into the low-pressure heat storage tank 26 for cooling, maintaining the temperature inside the low-pressure heat storage tank 26 at the saturation temperature corresponding to the extraction steam pressure in the low-pressure extraction steam pipeline 311. t 2. As the extracted steam continuously condenses into water, a pressure difference is formed inside the low-pressure heat storage tank 26. Therefore, the extracted steam in the turbine low-pressure extraction steam pipe tee 216 can continuously enter the low-pressure heat storage tank 26 until the low-pressure heat storage tank 26 reaches its maximum heat storage volume.

[0066] Steps A2 and A3 can be performed simultaneously or independently. Steps A2 and A3 increase the steam extraction rate from the turbine and store it in the resilient regenerative system, enhancing the load-reducing capacity of the coal-fired power unit. Simultaneously, the increased steam extraction rate reduces cold source losses, improving the economic efficiency of the coal-fired power unit.

[0067] When it is necessary to increase the load increase rate of coal-fired power units, the specific process of using the elastic regenerative system in this example for heat storage and peak shaving is as follows.

[0068] Step B1: When the coal-fired unit is running at low load, a load increase command is received.

[0069] Step B2: Flexible adjustment of high-pressure storage / heat supply energy release, specifically: opening the regulating valve group 15 of the high-pressure heat storage tank supply pipeline and the regulating valve group 110 of the feedwater bypass, releasing the heat stored in the high-pressure heat storage tank 16 to the water in the feedwater bypass, controlling the feedwater bypass water flow and the heat release of the high-pressure heat storage tank supply pipeline, so that the outlet water temperature of the feedwater bypass heater 13 is consistent with the outlet water temperature of the high-pressure heater group 316. After the working fluid in the high-pressure heat storage tank 16 releases heat, the resulting condensate enters the deaerator 312 through the high-pressure supply pipeline condensate 115.

[0070] Step B3: Flexible adjustment of low-pressure heat storage / supply to release energy, specifically: opening the regulating valve group 25 of the low-pressure heat storage tank supply pipeline and the regulating valve group 210 of the condensate bypass, releasing the heat stored in the low-pressure heat storage tank 26 to the water in the condensate bypass, controlling the condensate bypass water flow rate and the heat release of the low-pressure heat storage tank supply pipeline, so that the outlet water temperature of the condensate bypass heater 23 is consistent with the outlet water temperature of the low-pressure heater group 310. After the working fluid in the low-pressure heat storage tank 26 releases heat, the resulting condensate enters the condenser 37 through the low-pressure supply pipeline condensate 215.

[0071] Steps B2 and B3 can be operated simultaneously or independently. Through steps B2 and B3, the heat stored in the elastic regenerative system can be released to the regenerative unit of the steam turbine, thereby reducing the amount of steam extracted by the steam turbine and enhancing the load-up capacity of the coal-fired power generation unit.

[0072] Example 2

[0073] like Figure 2 As shown, a flexible regenerative system for improving the load change rate of a coal-fired power generation unit consists of a high-pressure storage / heat supply flexible regulation section, a low-pressure storage / heat supply flexible regulation section, and the original coal-fired power generation unit section. The high-pressure storage / heat supply flexible regulation section comprises a high-pressure heat storage tank, along with corresponding pipes, valves, tees, and other equipment. The low-pressure storage / heat supply flexible regulation section also comprises a high-pressure heat storage tank, along with corresponding pipes, valves, tees, and other equipment. The original coal-fired power generation unit section can be any type of coal-fired power generation unit, with typical components including a boiler, turbine, generator, condenser, heater, regenerative pipes, pumps, etc. Compared to the flexible regenerative system in the previous example, this example does not include a feedwater bypass heater 13 and a condensate bypass heater 23, nor their corresponding pipes and valves.

[0074] Specifically, in the high-pressure heat storage / supply flexible regulation section, the high-pressure heat storage tank 16 is connected to the turbine high-pressure extraction steam pipe tee 116 via the high-pressure heat storage tank storage pipe 112. The other end of the turbine high-pressure extraction steam pipe tee 116 is connected to the high-pressure extraction steam pipe 315 of the turbine high-pressure cylinder 33. To prevent extraction steam from flowing back into the turbine, a high-pressure check valve 114 is added to the high-pressure extraction steam pipe 315. The high-pressure heat storage tank storage pipe 112 is equipped with a high-pressure heat storage tank storage pipe regulating valve group 113, which includes any number of shut-off valves, regulating valves, and pressure reducing valves.

[0075] A high-pressure sprayer 17 is installed inside the high-pressure heat storage tank 16, and the high-pressure sprayer 17 is connected to the spray water through a high-pressure spray water supply pipe 19. A high-pressure spray regulating valve group 18 is installed on the high-pressure spray water supply pipe 19, which includes any number of shut-off valves, regulating valves, and pressure reducing valves. The spray water on the high-pressure spray water supply pipe 19 is preferably reheat desuperheating water or superheated desuperheating water from the unit, matched according to the pressure of the high-pressure heat storage tank 16.

[0076] In the low-pressure heat storage / heat supply flexible regulation section, the low-pressure heat storage tank 26 is connected to the turbine low-pressure extraction steam pipe tee 216 via the low-pressure heat storage tank energy storage pipe 212. The other end of the turbine low-pressure extraction steam pipe tee 216 is connected to the low-pressure extraction steam pipe 311 at the outlet of the turbine low-pressure cylinder 35. To prevent extraction steam from flowing back into the turbine, a low-pressure check valve 214 is added to the low-pressure extraction steam pipe 311. The low-pressure heat storage tank energy storage pipe 212 is equipped with a low-pressure heat storage tank energy storage pipe regulating valve group 213, which includes any number of shut-off valves, regulating valves, and pressure reducing valves.

[0077] The low-pressure heat storage tank 26 includes a low-pressure sprayer 27, which is connected to spray water via a low-pressure spray water pipe 29. The low-pressure spray water pipe 29 is equipped with a low-pressure spray water regulating valve assembly 28, which includes any number of shut-off valves, regulating valves, and pressure reducing valves. The spray water on the low-pressure spray water pipe 29 is preferably condensate from the outlet of the unit's condenser 37.

[0078] In the original coal-fired power generation unit section, the steam turbine includes a high-pressure cylinder 33 and a low-pressure cylinder 35. The high-pressure cylinder 33 is the high-pressure part of the steam turbine system and can be the ultra-high-pressure cylinder or high-pressure cylinder of the coal-fired power generation unit; the low-pressure cylinder 35 is the low-pressure part of the steam turbine system and can be the intermediate-pressure cylinder or low-pressure cylinder of the coal-fired power generation unit.

[0079] The high-pressure heater assembly 316 is arranged on the feedwater pipeline 314 and connected to the high-pressure cylinder 33 of the steam turbine via the high-pressure extraction steam pipeline 315. The low-pressure heater assembly 310 is arranged on the condensate pipeline 39 and connected to the low-pressure cylinder 35 of the steam turbine via the low-pressure extraction steam pipeline 311.

[0080] High-pressure steam pipe 32 connects boiler 31 and turbine high-pressure cylinder 33. Low-pressure steam pipe 34 connects turbine high-pressure cylinder 33 and turbine low-pressure cylinder 35. Exhaust pipe 36 connects turbine low-pressure cylinder 35 and condenser 37. Condensate pipe 39 connects condenser 37 and deaerator 312. Feedwater pipe 314 connects deaerator 312 and boiler 31.

[0081] Condensate pump 38 is located between condenser 37 and low-pressure heater group 310. Feedwater pump 313 is located between deaerator 312 and high-pressure heater group 316.

[0082] The principle behind the flexible regenerative system in this example for regulating the load change rate of a coal-fired power generator unit is as follows: The high-pressure and low-pressure flexible storage / heat supply sections are used to rapidly adjust the turbine's steam extraction rate, thereby changing the turbine's output and thus adjusting the load. Specifically, when the unit needs to reduce load, the steam extraction from the turbine is increased using the heat storage tank and stored there, thus increasing the unit's load reduction rate. When the unit needs to increase load, steam is released from the heat storage tank into the first regenerative unit, reducing the turbine's steam extraction rate, thereby increasing the unit's load increase rate.

[0083] When it is necessary to increase the load reduction rate of coal-fired units, the process of using the flexible regenerative system in this example for thermal storage and peak shaving is the same as the process in the above examples, specifically:

[0084] Step A1: When the coal-fired unit is running at high load, a load reduction command is received.

[0085] Step A2: Charge the high-pressure storage / heat supply flexible adjustment section, specifically: Open the regulating valve group 113 of the high-pressure heat storage tank's energy storage pipeline, and store the extracted steam in the high-pressure heat storage tank 16 through the turbine high-pressure extraction steam pipe tee 116. Simultaneously with the extraction steam entering the high-pressure heat storage tank 16, open the high-pressure spray regulating valve group 18 to spray water into the high-pressure heat storage tank 16 for cooling, maintaining the temperature inside the high-pressure heat storage tank 16 at the saturation temperature corresponding to the extraction steam pressure in the high-pressure extraction steam pipeline 315. t 1.

[0086] Step A3: Charge the low-pressure storage / heating flexible adjustment section, specifically: Open the regulating valve group 213 of the low-pressure heat storage tank's energy storage pipeline, and store the extracted steam in the low-pressure heat storage tank 26 through the turbine low-pressure extraction steam pipe tee 216. Simultaneously with the extraction steam entering the low-pressure heat storage tank 26, open the low-pressure spray water regulating valve group 28 to spray water into the low-pressure heat storage tank 26 for cooling, maintaining the temperature inside the low-pressure heat storage tank 26 at the saturation temperature corresponding to the extraction steam pressure in the low-pressure extraction steam pipeline 311. t 2.

[0087] Steps A2 and A3 above can be performed simultaneously or independently.

[0088] When it is necessary to increase the load ramp-up rate of the coal-fired unit, since there is no feedwater bypass heater 13 and condensate bypass heater 23 in the flexible regenerative system of this example, during the load ramp-up phase, the heat stored in the high-pressure heat storage tank 16 and the low-pressure heat storage tank 26 needs to be returned to the high-pressure heater group 316 and the low-pressure heater group 310 via the high-pressure heat storage tank energy storage pipeline 112 and the low-pressure heat storage tank energy storage pipeline 212. The specific process of using the flexible regenerative system of this example for heat storage and peak shaving is as follows.

[0089] Step C1: When the coal-fired unit is running at low load, a load increase command is received.

[0090] Step C2: Flexible adjustment of high-pressure storage / heat supply energy release, specifically: opening the regulating valve group 113 of the high-pressure heat storage tank energy storage pipeline, the working fluid stored in the high-pressure heat storage tank 16 flows into the high-pressure heater group 316 by gravity due to the pressure difference caused by the condensation of the working fluid in the high-pressure heater group 316, and exchanges heat with the water in the feedwater pipeline 314 in the high-pressure heater group 316, displacing the extracted steam in the high-pressure cylinder 33 of the steam turbine, thereby increasing the unit's load increase rate.

[0091] Step C3: Low-pressure storage / heating flexible adjustment of partial energy release, specifically: open the regulating valve group 213 of the low-pressure heat storage tank energy storage pipeline, the working fluid stored in the low-pressure heat storage tank 26 flows into the low-pressure heater group 310 by gravity due to the pressure difference caused by the condensation of the working fluid in the low-pressure heater group 310, and exchanges heat with the water in the condensate pipeline 310 in the low-pressure heater group 310, displacing the extracted steam in the low-pressure cylinder 35 of the steam turbine, thereby increasing the unit's load increase rate.

[0092] Steps C2 and C3 above can be performed simultaneously or independently.

[0093] Compared to the elastic regenerative system in the above example, the elastic regenerative system in this example does not have a feedwater bypass heater 13 and a condensate bypass heater 23, as well as corresponding pipes and valves. Therefore, the heat stored in the elastic regenerative system is returned to the original heater through the energy storage pipe to exchange heat with the water, making the system simpler.

[0094] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0095] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0096] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A resilient regenerative system for improving the load change rate of a coal-fired power generating unit, characterized in that, The resilient regenerative system includes: a steam turbine, a generator, a condenser, extraction steam pipes, exhaust steam pipes, a first regenerative unit, a second regenerative unit, a thermal storage unit, and a boiler; The generator is connected to the steam turbine, the inlet of the steam turbine is connected to the outlet of the boiler, the first outlet of the steam turbine is connected to the first inlet of the first regenerative unit through the extraction steam pipe, the second outlet of the steam turbine is connected to the inlet of the condenser through the exhaust steam pipe, the outlet of the condenser is connected to the second inlet of the first regenerative unit, and the outlet of the first regenerative unit is connected to the inlet of the boiler. The first regenerative unit includes a high-pressure heater group and a low-pressure heater group. The high-pressure heater group is arranged on the feedwater pipe, and the low-pressure heater group is arranged on the condensate pipe. The condensate pipe connects the condenser and the deaerator, and the feedwater pipe connects the deaerator and the boiler. The thermal storage unit includes: a high-pressure thermal storage tank, a high-pressure sprayer, a high-pressure spray water pipeline, a low-pressure thermal storage tank, a low-pressure sprayer, and a low-pressure spray water pipeline. The high-pressure thermal storage tank contains the high-pressure sprayer. The high-pressure spray water supply pipeline connects to the high-pressure sprayer through the first inlet of the high-pressure thermal storage tank. The second inlet of the high-pressure thermal storage tank connects to the first outlet of the steam turbine. The first outlet of the high-pressure thermal storage tank connects to the first inlet of the high-pressure heater group. The low-pressure thermal storage tank contains the low-pressure sprayer. The low-pressure spray water supply pipeline connects to the low-pressure sprayer through the first inlet of the low-pressure thermal storage tank. The second inlet of the tank is connected to the first outlet of the steam turbine, and the first outlet of the low-pressure heat storage tank is connected to the first inlet of the low-pressure heater group. The high-pressure sprayer is used to maintain the temperature in the high-pressure heat storage tank at the saturation temperature corresponding to the extraction steam pressure in the extraction steam pipeline during the load reduction phase. The spray water on the high-pressure spray water supply pipeline is the desuperheating water of the reheater or the superheating desuperheating water of the unit. The low-pressure sprayer is used to maintain the temperature in the low-pressure heat storage tank at the saturation temperature corresponding to the extraction steam pressure in the extraction steam pipeline during the load reduction phase. The spray water on the low-pressure spray water supply pipeline is the condensate at the condenser outlet. The second regenerative unit includes: a condensate bypass heater and a feedwater bypass heater; The heat source inlet of the feedwater bypass heater is connected to the second outlet of the high-pressure heat storage tank, the cold source inlet of the feedwater bypass heater is connected to the feedwater bypass water intake, the heat source outlet of the feedwater bypass heater is connected to the inlet of the boiler, and the cold source outlet of the feedwater bypass heater is connected to the inlet of the deaerator. The heat source inlet of the condensate bypass heater is connected to the second outlet of the low-pressure heat storage tank, the cold source inlet of the condensate bypass heater is connected to the condensate bypass water intake, the heat source outlet of the condensate bypass heater is connected to the inlet of the deaerator, and the cold source outlet of the condensate bypass heater is connected to the outlet of the condenser.

2. The elastic regenerative system for increasing the variable load rate of a coal-fired power generating unit according to claim 1, characterized in that, The steam turbine consists of multiple cylinders with different pressure levels. The number of first regenerative units, second regenerative units and / or heat storage units is at least one. A single first regenerative unit and / or heat storage unit is connected to at least one cylinder in the steam turbine, and a single second regenerative unit is connected to at least one heat storage unit.

3. The elastic regenerative system for increasing the variable load rate of a coal-fired power generating unit according to claim 1, characterized in that, A pump set is installed between the condenser and the first regenerative unit.

4. The elastic regenerative system for increasing the variable load rate of a coal-fired power generating unit according to claim 1, characterized in that, A check valve is installed at the first outlet of the steam turbine.

5. A method for elastic regenerative heating to increase the load change rate of a coal-fired power generating unit, characterized in that, The elastic regenerative method is implemented by the elastic regenerative system for increasing the load change rate of a coal-fired power generating unit as described in any one of claims 1 to 4, and includes: a normal operation phase, a load reduction phase, and a load increase phase; During normal operation, a portion of the heat energy from the steam extracted from the turbine is used to heat the condensate formed by the steam exhaust from the turbine in the first regenerative unit, and the heated condensate is then used as boiler feedwater to the boiler. During the load reduction phase, a portion of the turbine extraction steam is pre-stored in a heat storage tank, and the temperature inside the heat storage tank is maintained at the saturation temperature corresponding to the extraction steam pressure in the extraction steam pipeline by spraying water into the heat storage tank. During the load increase phase, a portion of the working fluid stored in the heat storage tank flows into the first regenerative unit by gravity due to the pressure difference between it and the liquid formed by the condensation of the working fluid in the first regenerative unit. In the first regenerative unit, it participates in the process of heating condensate by steam extraction from the steam turbine. The working fluid is a mixture formed by steam extraction and water spraying.

6. The elastic regenerative method for increasing the load change rate of a coal-fired power generating unit according to claim 5, characterized in that, The elastic regenerative method further includes: During the load increase phase, another portion of the working fluid stored in the heat storage tank is transported to the second regenerative unit to exchange heat with the cold water, and the hot water after heat exchange is transported to the boiler as boiler feedwater, while the condensate after heat exchange is transported to the first regenerative unit as condensate.

7. The elastic regenerative method for increasing the load change rate of a coal-fired power generating unit according to claim 6, characterized in that, The water temperature at the outlet of the first regenerating unit is the same as the water temperature at the heat source outlet of the second regenerating unit.

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