A solid thermal storage power generation peak-shaving and frequency-regulating system and working method for a thermal power plant

Abstract

The present invention discloses a solid heat storage power generation peak-shaving and frequency-modulation system and a working method for a thermal power plant, including a solid heat storage electric boiler and its water supply pipeline and steam connection pipeline, and a unit peak-shaving control unit. The solid heat storage electric boiler includes a solid heat storage brick, a peak-shaving and frequency-modulation electric heater, a high-temperature resistant fan and a wind-water heat exchanger. During the valley power period, the peak-shaving and frequency-modulation electric heater supplies power to heat the solid heat storage brick, and during the non-valley power period, the high-temperature resistant fan draws air into the solid heat storage electric boiler to exchange heat with the solid heat storage brick to form hot air. The wind-water heat exchanger uses hot air to heat the water in the water supply pipeline into superheated steam, and the superheated steam is sent into the steam turbine to drive the generator to generate electricity. The beneficial effect of the present invention is that the excess electricity of the thermal power plant is stored in the solid heat storage bricks during the low power consumption period, and the power generation of the thermal power plant is assisted to increase during the peak power consumption period, thereby realizing the thermal storage peak-shaving and frequency modulation of the thermal power plant.

Description

Technical Field

[0001] The invention relates to the field of energy utilization, and in particular to a solid thermal storage power generation peak-shaving and frequency modulation system and a working method for a thermal power plant. Background Art

[0002] Energy storage power stations are urgently needed to improve the efficiency, safety and economy of conventional energy generation and transmission. In order to meet the requirements of power load, the current installed power generation capacity and grid capacity are built according to the maximum demand. As the peak-to-valley difference of the grid increases, it will inevitably lead to the shutdown or low-load operation of generators during non-peak power consumption and waste of grid capacity. In 2011, the total load factor of conventional coal-fired power generation units in China was only 51.8%, and the load utilization factor of the grid was also less than 55%. Using energy storage power stations to store energy can greatly improve the actual operating efficiency of thermal power units and enhance the transmission capacity of the grid. Taking 2011 as an example, if the system is increased to 80%, it can reduce the construction of 210 million kilowatts of thermal power installed capacity and 25% of grid capacity, which is equivalent to reducing investment by 1.05 trillion yuan, and saving 30 million tons of standard coal each year.

[0003] In the past 10 years, major developed countries have launched national research programs on power energy storage systems, including the United States, Japan, the United Kingdom, the European Union and Australia. It is expected that by 2050, the capacity of the world's power energy storage system will increase from the current 3.0% (128GW) of total power generation to 10% to 15%, or even higher. As of 2011, my country's energy storage installed capacity was 17GW, accounting for about 1.6% of the country's total power installed capacity, far below the world average of 2.6%; by 2020, my country's power energy storage installed capacity needs to reach more than 70GW, accounting for 4.0% to 5.0% of the country's total power installed capacity. Existing energy storage technologies include pumped storage, compressed air energy storage (CAES), thermal storage, batteries, superconductors, flywheels and supercapacitors. By comparing these energy storage technologies, we can find that except for pumped storage, compressed air energy storage and thermal storage, the single-unit capacity of three physical energy storage technologies can reach or exceed 100MW, the other energy storage technologies are all below 10MW or even 1MW. Only these three physical energy storage technologies have low costs, not exceeding US$100 / kw·h, and have a long energy storage life.

[0004] Common medium and high temperature heat storage materials include solid heat storage bricks, steam, water, thermal oil, liquid metal, air, molten salt, etc. If medium and high temperature solid heat storage bricks can be used, high temperature steam can be generated during peak electricity consumption periods to enter the steam turbine to increase power generation. During low electricity consumption periods, electric heaters can be used to heat the solid heat storage bricks to achieve peak and frequency regulation heat storage, thus realizing flexible peak and frequency regulation of thermal power plants and other auxiliary services. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention aims to provide a solid thermal storage power generation peak-shaving and frequency-regulating system and a working method for a thermal power plant.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a solid thermal storage power generation peak-shaving and frequency-regulating system for a thermal power plant, comprising a solid thermal storage electric boiler and its water supply pipeline and steam connection pipeline, and a unit peak-shaving control unit;

[0008] The solid heat storage electric boiler includes solid heat storage bricks, peak-shaving and frequency-modulating electric heaters, high-temperature resistant fans, and wind-water heat exchangers;

[0009] The peak-shaving and frequency-modulating electric heater utilizes the surplus power of peak-shaving or frequency-modulating power from the thermal power plant to heat the solid heat storage bricks;

[0010] The high temperature resistant fan draws air from the power plant boiler into the solid thermal storage electric boiler to exchange heat with the solid thermal storage bricks to form hot air;

[0011] The water supply pipeline is connected to the deaerator or condenser of the thermal power plant, and the feed water or condensed water is sent to the wind-water heat exchanger after being pressurized by a low-pressure feed water pump;

[0012] The wind-water heat exchanger transfers the heat of the hot air to the water supply pipeline, causing the water supply to evaporate and become superheated steam;

[0013] The steam connection pipeline delivers the superheated steam generated by the solid thermal storage electric boiler into the steam turbine to perform work and drive the generator to generate electricity.

[0014] Furthermore, the power supply for the peak-shaving and frequency-regulating electric heater arranged in the solid thermal storage electric boiler comes from the generator export bus, the plant power bus or the plant bus after the booster station, and the peak-shaving or frequency-regulating electricity of the thermal power plant is used to meet the power supply of the peak-shaving and frequency-regulating electric heater.

[0015] Furthermore, the peak-shaving and frequency-modulating electric heater is an electric heating plate or electric heating wire arranged in a solid heat storage brick.

[0016] Furthermore, the superheated steam generated by the solid heat storage electric boiler is sent to a small heat storage steam turbine through a steam connecting pipeline, and the small heat storage steam turbine drives a small generator to generate electricity, or is sent to any of the inlets of the power station boiler reheater, the medium-pressure cylinder inlet or the low-pressure cylinder inlet, and the superheated steam generated by the solid heat storage electric boiler is used to do work in the turbine to drive the generator to generate electricity.

[0017] Furthermore, the exhaust steam of the small heat storage steam turbine enters the condenser of the small heat storage steam turbine for condensation or is sent to the large condenser of the thermal power plant for condensation.

[0018] Furthermore, the peak-shaving and frequency-regulating system participates in any one or combination of auxiliary services such as peak-shaving, frequency regulation, interruptible load, and black start of thermal power plants.

[0019] Furthermore, a high-temperature flue gas heat exchanger is arranged in the solid thermal storage electric boiler, connected to the flue gas supply and return pipeline of the power station boiler, and the high-temperature flue gas of the power station boiler is extracted to heat the solid thermal storage bricks.

[0020] Furthermore, a high-temperature steam heat exchanger is arranged in the solid thermal storage electric boiler, connected to a high-temperature steam pipeline, and the solid thermal storage bricks are heated by high-temperature steam. The high-temperature steam comes from any one of the main steam of the power station boiler, reheated steam or turbine extraction steam.

[0021] Furthermore, the heat storage material of the solid heat storage brick includes any one of concrete, solid magnesia brick, solid heat-resistant brick, solid heat-resistant sand, sand, and soil.

[0022] Furthermore, the solid thermal storage electric boiler has single-stage, two-stage, three-stage or multi-stage thermal storage; the temperature inside the single-stage solid thermal storage electric boiler is above 350 degrees.

[0023] A second aspect of the present invention provides a working method of a solid thermal storage power generation peak-shaving and frequency-modulating system in a thermal power plant, comprising the following steps:

[0024] S1. According to the site conditions in the thermal power plant, design and select the best solid thermal storage material for the solid thermal storage electric boiler, and design the number of thermal storage stages and the thermal storage temperature working range of the solid thermal storage material of each stage of the solid thermal storage electric boiler;

[0025] S2. According to the temperature of the solid thermal storage material of each stage of the solid thermal storage electric boiler, the corresponding thermal storage heat source is selected, and the peak-shaving frequency-modulating electric heater driven by the peak-shaving frequency-modulating electricity is used as the thermal storage heat source; or the high-temperature flue gas, main steam, reheated steam or large steam turbine extraction steam of the power station boiler is used as the thermal storage heat source;

[0026] S41. According to the current operation status of the thermal power plant, if there is surplus peak-shaving and frequency-regulating power to drive the peak-shaving and frequency-regulating electric heater, then jump to step S42; if the power plant boiler allows the extraction of high-temperature flue gas for heating the solid thermal storage bricks, then jump to step S43; if the thermal power plant has surplus main steam, reheat steam or large steam turbine extraction steam for heating the solid thermal storage bricks, then jump to step S44;

[0027] S42, using the surplus peak-shaving and frequency-modulating electricity to power the peak-shaving and frequency-modulating electric heater of the solid thermal storage electric boiler, and using electric heating to make the solid thermal storage bricks reach their thermal storage temperature;

[0028] S43, opening the heating smoke outlet valve of the flue gas heat exchanger, the high-temperature flue gas from the power station boiler enters the heat release gas inlet valve of the high-temperature flue gas heat exchanger and is then discharged from the outlet valve back to the flue of the power station boiler; the solid heat storage bricks in the solid heat storage electric boiler absorb the heat of the high-temperature flue gas and reach their heat storage temperature;

[0029] S44, opening the heating steam inlet valve and outlet valve of the high-temperature steam heat exchanger, and the high-temperature steam drawn from the main steam, reheated steam or steam extraction of the power plant boiler of the thermal power plant enters the high-temperature steam heat exchanger to release heat, and then is discharged from the outlet valve back to the thermal system of the thermal power plant; the solid heat storage bricks in the solid heat storage electric boiler absorb the heat of the high-temperature steam and reach their heat storage temperature;

[0030] S5. The steam generated by heating with solid thermal storage electric boiler enters the large steam turbine of the thermal power plant to drive the generator to increase the power generation, thereby increasing the peak capacity of the thermal power plant during the peak period of power demand and reducing the use of coal in its power station boiler.

[0031] The beneficial effects of the present invention are:

[0032] 1) In the solid thermal storage power generation peak-shaving and frequency-modulation system of the thermal power plant of the present invention, the solid thermal storage electric boiler uses the peak-shaving and frequency-modulation power through the electric heater to achieve heat storage, saving energy, and can assist in increasing the power generation of the thermal power plant during the peak load period of electricity consumption. During the low electricity consumption period, the excess electricity of the thermal power plant can be stored in the solid thermal storage bricks, thereby realizing the thermal storage peak-shaving and frequency modulation of the thermal power plant.

[0033] 2) The solid thermal storage power generation peak-shaving and frequency regulation system of thermal power plants is set up in thermal power plants, making full use of existing thermal power unit equipment, without the need to build new generating units, thus saving huge investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a general schematic diagram of the solid thermal storage power generation peak-shaving and frequency-regulating system of a thermal power plant in Example 1 of the present invention;

[0035] Figure 2 This is a schematic diagram of a solid thermal storage power generation peak-shaving and frequency-regulating system for a thermal power plant in Example 2 of the present invention;

[0036] Figure 3 This is a schematic diagram of a solid thermal storage power generation peak-shaving and frequency-regulating system for a thermal power plant in Example 3 of the present invention;

[0037] Figure 4 It is a flow chart of the working method of the solid thermal storage power generation peak-shaving and frequency modulation system of a thermal power plant in Example 4 of the present invention.

[0038] Reference numerals

[0039] 1-power station boiler, 2-large steam turbine, 3-generator, 4-large condenser, 5-low-pressure heater, 6-deaerator, 7-high-pressure heater, 8-low-pressure feedwater pump, 9-solid heat storage electric boiler, 10-peak-shaving and frequency-regulating electric heater, 11-small heat storage steam turbine, 12-wind-water heat exchanger, 13-high-temperature flue gas heat exchanger, 14-high-temperature steam heat exchanger, 15-unit peak-shaving and frequency-regulating control unit, 16-small generator, 17-high-temperature resistant fan, 18-solid heat storage bricks, 19-water supply pipeline, 20-steam communication pipeline, 21-small heat storage steam turbine condenser. DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with the accompanying drawings. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to this embodiment.

[0041] Example 1

[0042] like Figure 1 As shown, a solid thermal storage power generation peak-shaving and frequency-regulating system for a thermal power plant includes a solid thermal storage electric boiler 9 and its water supply pipeline 19, a steam connection pipeline 20 and a unit peak-shaving and frequency-regulating control unit 15. The solid thermal storage electric boiler includes a solid thermal storage brick 18, a peak-shaving and frequency-regulating electric heater 10, a high-temperature resistant fan 17 and a wind-water heat exchanger 12. The solid thermal storage power generation peak-shaving and frequency-regulating system for a thermal power plant is arranged in a thermal power plant. The power station boiler 1 in the thermal power plant burns pulverized coal to heat the water in the boiler, generates water vapor, drives the large steam turbine 2 to move and generate kinetic energy, and the large steam turbine drives the rotor of the generator 3 to move, cuts the magnetic lines of force and generates electricity. The steam that releases the thermal potential energy is discharged from the exhaust port of the large steam turbine 2, sent to the condenser 4 for cooling, and re-condensed into water. The condensed water is sent to the low-pressure heater 5 by the condensate pump and finally returns to the deaerator 6. Part of the water in the deaerator 6 is sent to the high-pressure heater 7 and returned to the power station boiler. Part of the water is sent to the water supply pipeline 19 in the solid thermal storage electric boiler 9 through the low-pressure feed water pump 8, and then sent to the wind-water heat exchanger 12 for heat exchange. The high-temperature resistant fan 17 in the solid thermal storage electric boiler draws the air of the power station boiler 1 into the solid thermal storage electric boiler 9 and exchanges heat with the solid thermal storage bricks 18 to become hot air, and then sends it to the wind-water heat exchanger 12. The wind-water heat exchanger 12 receives the hot air and transfers the heat of the hot air to the water supplied by the water supply pipeline 19, causing it to evaporate and become superheated steam. The superheated steam enters the steam connection pipeline 20.

[0043] The steam connection pipeline 20 connects the reheater (not shown) and the small heat storage steam turbine 11 in the thermal power plant, the reheater is connected to the large steam turbine 2, and the small heat storage steam turbine 11 is connected to the small generator 16, the small heat storage steam turbine condenser 21 and the large condenser 4. The large steam turbine 2 and the generator 3 are existing units in the thermal power plant, and the small heat storage steam turbine 11 and the small generator 16 can be newly invested and constructed thermal power units, and the power generation capacity is smaller than the large steam turbine 2 and the generator 3 of the thermal power plant.

[0044] The solid heat storage electric boiler 9 includes a solid heat storage brick 18, a peak frequency modulation electric heater 10, a high temperature resistant fan 17 and a wind and water heat exchanger 12. The solid heat storage brick is a rectangular parallelepiped, and the sensible heat storage material used in this embodiment is used to make the solid heat storage brick, and the sensible heat storage material includes any one of concrete, solid heat storage magnesium brick, solid heat resistant brick, solid heat resistant sand, and high temperature resistant heat transfer oil. Preferably, the solid heat storage brick in this embodiment is a solid heat storage magnesium brick, which is arranged in multiple layers in the furnace body of the solid heat storage electric boiler, and the peak frequency modulation electric heater 10 is arranged between each layer of solid heat storage bricks. The peak frequency modulation electric heater 10 is composed of an electric heating plate or an electric heating wire, and the electric heating plate or the electric heating wire is made of a high-voltage heating resistor. The high-voltage alternating current generates heat after passing through the electric heating plate or the electric heating wire, heating the solid heat storage brick to achieve heat storage. There is a gap for air to pass between each solid heat storage brick and the solid heat storage brick and the furnace body of the solid heat storage electric boiler. During the period of low electricity consumption, the unit peak-shaving and frequency-regulating control unit 15 uses the surplus electricity to heat the solid heat storage bricks to a certain temperature through the peak-shaving and frequency-regulating electric heater 10 for energy storage.

[0045] The unit peak-shaving and frequency-modulation control unit 15 controls the charging of the solid thermal storage electric boiler 9 according to the dispatching instructions of the power plant centralized control system of the upper power grid. When the power supply is surplus, the power plant centralized control system controls the unit peak-shaving and frequency-modulation control unit 15 to charge and store heat in the solid thermal storage electric boiler 9. The peak-shaving and frequency-modulation electric heater 10 uses the power supplied by the unit peak-shaving and frequency-modulation control unit 15 to heat the solid thermal storage brick 18. The peak-shaving and frequency-modulation electric heater 10 arranged in the solid thermal storage electric boiler is powered by the generator export bus, the plant power bus or the plant bus after the booster station, and the peak-shaving and frequency-modulation power of the thermal power plant is used to meet the power supply of the electric heater. The generator export bus is the generator terminal voltage bus, and the generator export bus is connected to the plant power bus through a reactor.

[0046] When the power supply is tight, the solid thermal storage electric boiler 9 releases heat to generate electricity. The low-pressure heater 5 in the thermal power plant is connected to the deaerator or condenser, and the feed water or condensate is sent to the wind-water heat exchanger 12 arranged in the solid thermal storage electric boiler through the water supply pipeline 19 by the low-pressure feed water pump 8. The high-temperature resistant fan 17 pushes the air through the air duct to the solid thermal storage brick 18. The solid thermal storage brick heats the air passing through. The heated air flows into the fin tube of the wind-water heat exchanger 12, heats the liquid in the fin tube, and then enters the high-temperature resistant fan to continue to circulate. The high-temperature steam generated by the liquid in the fin tube after heating enters the steam connection pipeline 20. The superheated steam is sent to the small thermal storage steam turbine 11 through the steam connection pipeline 20 to generate power, or sent to the reheater of the thermal power unit. After the steam temperature is further increased, it enters the medium-pressure cylinder of the large steam turbine 2 to generate power. The steam after releasing heat in the small heat storage steam turbine 11 enters the small heat storage steam turbine condenser 21 for cooling or enters the large condenser 4 of the large steam turbine 2 for cooling.

[0047] In a preferred embodiment, the solid heat storage brick is a rectangular parallelepiped with multiple hollow through holes, and the electric heating wire passes through the hollow through holes to heat the solid heat storage brick and improve the heating efficiency.

[0048] The solid thermal storage electric boiler is a single-stage, two-stage, three-stage or multi-stage thermal storage device, and the temperature in the single-stage thermal storage device is above 300 degrees. When the solid thermal storage electric boiler is a two-stage thermal storage device, the two-stage thermal storage devices are connected in parallel or in series. When the solid thermal storage electric boiler is a three-stage thermal storage device or a multi-stage thermal storage device, the thermal storage devices at each stage are connected in parallel, in series or in series-parallel.

[0049] In this embodiment, the wind-water heat exchanger 12 is a low-pressure fin-tube heat exchanger. The high-temperature resistant fan 17 can circulate high-temperature air.

[0050] In a preferred embodiment, the exterior of the furnace body of the solid thermal storage electric boiler is also coated with a thermal insulation layer to reduce heat loss.

[0051] The solid heat storage peak-shaving and frequency regulation system of a thermal power plant can participate in any one or combination of auxiliary services such as peak-shaving, frequency regulation, interruptible load, and black start of the thermal power plant. When the thermal power plant needs to reduce the amount of electricity connected to the grid, the electric energy is stored in the solid heat storage bricks of the solid heat storage electric boiler. When the thermal power plant needs to increase the amount of electricity generated, the heat energy stored in the solid heat storage bricks of the solid heat storage electric boiler is converted into electric energy and connected to the power grid, thereby realizing power grid auxiliary services such as power frequency regulation and peak-shaving. When a power outage occurs, the present invention can also use the solid heat storage electric boiler as a black start power source. At this time, the heat energy stored in the solid heat storage bricks in the solid heat storage electric boiler heats the cooling water to generate high-temperature steam, which is sent to the small heat storage steam turbine 11. The small generator 16 generates alternating current, which is output to the bus of the booster station after boosting. After the transmission line is charged, the large units of the thermal power plant are started, and the started units are connected to the grid to restore the power generation capacity, thereby realizing a black start. When the power company must interrupt a certain amount of load, the power dispatching center of the power grid sends a dispatching instruction to the unit peak-shaving and frequency regulation control unit 15, converting part of the electricity into thermal energy and storing it in the solid thermal storage bricks in the solid thermal storage electric boiler. The thermal energy in the solid thermal storage bricks in the solid thermal storage electric boiler can be converted into electrical energy again and sold to users, thereby achieving peak-shaving electricity prices to regulate supply and demand, optimize the redistribution of limited market resources, and maximize social benefits.

[0052] Example 2

[0053] like Figure 2 As shown, in this embodiment, a high-temperature flue gas heat exchanger 13 is also arranged in the solid thermal storage electric boiler 9, which is connected to the flue gas supply and return pipeline of the power station boiler 1 of the thermal power plant. The flue gas supply and return pipeline includes a flue gas supply pipeline and a flue gas return pipeline. An inlet valve is arranged on the flue gas supply pipeline, and an outlet valve is arranged on the flue gas return pipeline. When it is necessary to store heat for the solid thermal storage bricks, the inlet valve on the flue gas supply pipeline is opened, and the high-temperature resistant fan 17 draws the high-temperature flue gas of the power station boiler of the thermal power plant through the flue gas supply pipeline to heat the solid thermal storage bricks. After the solid thermal storage bricks in the solid thermal storage electric boiler absorb the heat of the high-temperature flue gas, they reach their heat storage temperature. After the heat exchange is completed, the low-temperature flue gas is discharged from the outlet valve, returned to the power station boiler 1 through the flue gas return pipeline, and discharged through the exhaust pipe of the power station boiler. When the solid heat storage bricks are required to release heat energy to generate electricity, the high temperature resistant fan 17 pushes the air through the air duct to the solid heat storage bricks, and the solid heat storage bricks heat the air passing through. The heated air flows into the finned tubes of the wind-water heat exchanger 12, heats the liquid in the finned tubes, and then enters the high temperature resistant fan to continue circulating. The high temperature steam generated by the heated liquid in the finned tubes enters the steam connection pipeline 20. The high temperature steam drives the large steam turbine 2 or the small heat storage steam turbine to rotate and generate electricity, and the low temperature steam after heat exchange is sent to the condenser 4 of the large steam turbine 2 or the small heat storage steam turbine condenser 21 of the small heat storage steam turbine for cooling.

[0054] Example 3

[0055] like Figure 3 As shown, in this embodiment, a high-temperature steam heat exchanger 14 is also arranged in the solid thermal storage electric boiler. The high-temperature steam heat exchanger 14 is connected to the high-temperature steam pipeline. The high-temperature steam pipeline is connected to the main steam pipeline of the power station boiler of the thermal power plant through the inlet valve, the reheater pipeline and the steam extraction pipeline of the steam turbine, and extracts any one of the high-temperature steam from the main steam, reheated steam or steam turbine extraction of the power station boiler of the thermal power plant. After the solid thermal storage bricks in the solid thermal storage electric boiler absorb the heat of the high-temperature steam, they reach their heat storage temperature. When the solid thermal storage bricks are required to release heat energy to generate electricity, the high-temperature resistant fan 17 pushes the air through the air duct to the solid thermal storage bricks, and the solid thermal storage bricks heat the air flowing through. The heated air flows to the fin tubes of the wind-water heat exchanger 12, heats the liquid in the fin tubes, and then enters the high-temperature resistant fan to continue to circulate. The high-temperature steam generated after the liquid in the fin tubes is heated enters the steam connection pipeline 20 through the outlet valve. The steam connection pipeline 20 sends high-temperature steam to the large steam turbine 2 or the small heat storage steam turbine 11. The high-temperature steam drives the large steam turbine 2 or the small heat storage steam turbine to rotate and generate electricity, and the low-temperature steam after heat exchange is sent to the condenser 4 of the large steam turbine 2 or the small heat storage steam turbine condenser 21 of the small heat storage steam turbine for cooling.

[0056] Example 4

[0057] like Figure 4 As shown, this embodiment provides a working method of the solid thermal storage power generation peak-shaving and frequency-regulating system of a thermal power plant as described above, comprising the following steps:

[0058] S1. According to the site conditions in the thermal power plant, design and select the best solid thermal storage material for the solid thermal storage electric boiler, and design the thermal storage stages and the thermal storage temperature working range of the solid thermal storage material of each stage of the solid thermal storage electric boiler; the thermal storage material includes any one of concrete, solid magnesium bricks, solid heat-resistant bricks, solid heat-resistant sand, sand, and soil. According to the peak-shaving and frequency-regulating capabilities of the thermal power plant, as well as the selected solid thermal storage material of the solid thermal storage electric boiler and the thermal storage temperature working range of the solid thermal storage material, design the thermal storage stages of the solid thermal storage electric boiler.

[0059] S2. According to the temperature of the solid thermal storage material of each stage of the solid thermal storage electric boiler 9, a corresponding thermal storage heat source is selected, and a peak-shaving and frequency-modulating electric heater driven by peak-shaving and frequency-modulating electricity is used as a thermal storage heat source; or high-temperature flue gas, main steam, reheated steam or large steam turbine extraction steam of a power station boiler is used as a thermal storage heat source;

[0060] S41. According to the current operation status of the thermal power plant, if there is surplus peak-shaving and frequency-regulating power to drive the peak-shaving and frequency-regulating electric heater, then jump to step S42; if the power plant boiler allows the extraction of high-temperature flue gas for heating the solid heat storage bricks 18, then jump to step S43; if the thermal power plant has surplus main steam, reheat steam or large steam turbine extraction steam for heating the solid heat storage bricks 18, then jump to step S44;

[0061] S42, using the surplus peak-shaving and frequency-modulating electricity to power the peak-shaving and frequency-modulating electric heater of the solid thermal storage electric boiler, and using electric heating to make the solid thermal storage bricks reach their thermal storage temperature;

[0062] S43, opening the heating flue gas inlet valve of the high-temperature flue gas heat exchanger, the high-temperature flue gas from the power station boiler enters the high-temperature flue gas heat exchanger to release heat, and then is discharged from the outlet valve back to the flue of the power station boiler; the solid heat storage bricks in the solid heat storage electric boiler absorb the heat of the high-temperature flue gas and reach their heat storage temperature;

[0063] S44, opening the heating steam inlet valve and outlet valve of the high-temperature steam heat exchanger, and the high-temperature steam drawn from the main steam, reheated steam or steam extraction of the power plant boiler of the thermal power plant enters the high-temperature steam heat exchanger to release heat, and then is discharged from the outlet valve back to the thermal system of the thermal power plant; the solid heat storage bricks in the solid heat storage electric boiler absorb the heat of the high-temperature steam and reach their heat storage temperature;

[0064] S5. The steam generated by heating with solid thermal storage electric boiler enters the large steam turbine of the thermal power plant to drive the generator to increase the power generation, thereby increasing the peak capacity of the thermal power plant during the peak period of power demand and reducing the use of coal in its power station boiler.

[0065] For those skilled in the art, various corresponding changes and modifications can be made according to the above technical solutions and concepts, and all of these changes and modifications should be included in the protection scope of the claims of the present invention.

Claims

1. A solid thermal storage power generation peak-shaving and frequency modulation system for a thermal power plant, characterized in that: It includes a solid heat storage electric boiler (9) and its water supply pipeline (19) and steam connection pipeline (20), and a unit peak regulation control unit (15); The solid heat storage electric boiler (9) comprises a solid heat storage brick (18), a peak-shaving and frequency-modulating electric heater (10), a high-temperature resistant fan (17), and a wind-water heat exchanger (12); A high-temperature flue gas heat exchanger (13) is also arranged in the solid thermal storage electric boiler (9), connected to the power station boiler flue gas supply and return pipeline, and extracts the high-temperature flue gas of the power station boiler to heat the solid thermal storage bricks (18); The peak-shaving and frequency-modulating electric heater (10) utilizes the peak-shaving or frequency-modulating surplus power of a thermal power plant to heat the solid heat storage brick (18); The high temperature resistant blower (17) draws air from the power station boiler (1) of the thermal power plant into the solid heat storage electric boiler (9) to exchange heat with the solid heat storage bricks (18) to generate hot air; The water supply pipeline (19) is connected to the deaerator (6) or condenser (4) of the thermal power plant, and the feed water or condensed water is pressurized by the low-pressure feed water pump (8) and sent to the air-water heat exchanger (12); The air-water heat exchanger (12) transfers the heat of the hot air to the water supply pipeline (19), causing the water supply to evaporate into superheated steam; The steam connection pipeline (20) sends the superheated steam generated by the solid thermal storage electric boiler (9) into the steam turbine to perform work and drive the generator to generate electricity; The superheated steam generated by the solid heat storage electric boiler (9) is fed into a small heat storage steam turbine (11) through a steam connecting pipe (20), and the small heat storage steam turbine (11) drives a small generator (16) to generate electricity, or is fed into any one of the inlet of the power station boiler reheater, the inlet of the intermediate pressure cylinder, or the inlet of the low pressure cylinder, and the superheated steam generated by the solid heat storage electric boiler (9) is used to perform work in the steam turbine (2) to drive the generator (3) to generate electricity.

2. The solid thermal storage power generation peak-shaving and frequency modulation system of a thermal power plant according to claim 1, characterized in that: The power supply for the peak-shaving and frequency-modulating electric heater (10) arranged in the solid heat storage electric boiler (9) is from the generator outlet bus, the plant power bus or the factory bus after the booster station, and the peak-shaving or frequency-modulating power of the thermal power plant is used to meet the power supply of the peak-shaving and frequency-modulating electric heater (10).

3. The solid thermal storage power generation peak-shaving and frequency modulation system of a thermal power plant according to claim 1, characterized in that: The peak-shaving and frequency-modulating electric heater (10) is an electric heating plate or electric heating wire arranged in a solid heat storage brick (18).

4. The solid thermal storage power generation peak-shaving and frequency modulation system of a thermal power plant according to claim 1, characterized in that: The exhaust steam of the small heat storage steam turbine (11) enters the small heat storage steam turbine condenser (21) for condensation or is sent to the large condenser (4) of the thermal power plant for condensation.

5. The solid thermal storage power generation peak-shaving and frequency modulation system of a thermal power plant according to claim 1, characterized in that: The peak-shaving and frequency-regulating system participates in any one or combination of auxiliary services such as peak-shaving, frequency regulation, interruptible load, and black start of thermal power plants.

6. The solid thermal storage power generation peak-shaving and frequency modulation system of a thermal power plant according to claim 1, characterized in that: A high-temperature steam heat exchanger (14) is arranged in the solid thermal storage electric boiler (9), connected to a high-temperature steam pipeline, and uses high-temperature steam to heat the solid thermal storage bricks (18). The high-temperature steam comes from any one of the main steam of the power station boiler, reheated steam or steam extraction from the steam turbine.

7. The solid thermal storage power generation peak-shaving and frequency modulation system of a thermal power plant according to claim 1, characterized in that: The heat storage material of the solid heat storage brick (18) includes any one of concrete, solid magnesia brick, solid heat-resistant brick, solid heat-resistant sand, sand, and soil.

8. The solid thermal storage power generation peak-shaving and frequency modulation system of a thermal power plant according to claim 1, characterized in that: The solid heat storage electric boiler (9) is single-stage, two-stage, three-stage or multi-stage heat storage; the temperature inside the single-stage solid heat storage electric boiler is above 350 degrees.

9. A method for operating the solid thermal storage power generation peak-shaving and frequency modulation system of a thermal power plant according to any one of claims 1 to 8, characterized in that: The steps include: S1. Design and select the best solid thermal storage material for the solid thermal storage electric boiler (9) according to the site conditions in the thermal power plant, and design the number of thermal storage stages and the thermal storage temperature operating range of the solid thermal storage material for each stage of the solid thermal storage electric boiler (9); S2. According to the temperature of the solid thermal storage material of each stage of the solid thermal storage electric boiler (9), a corresponding thermal storage heat source is selected, and a peak-shaving frequency-modulating electric heater driven by peak-shaving frequency-modulating electricity is used as the thermal storage heat source; or high-temperature flue gas, main steam, reheated steam or large steam turbine extraction steam from a power station boiler is used as the thermal storage heat source; S41. Based on the current operating status of the thermal power plant, if there is surplus peak-shaving and frequency-regulating power to drive the peak-shaving and frequency-regulating electric heater, then jump to step S42; if the power plant boiler allows the extraction of high-temperature flue gas for heating the solid heat storage bricks (18), then jump to step S43; If the thermal power plant has surplus main steam, reheat steam or large steam turbine extraction steam for heating the solid heat storage bricks (18), then jump to step S44; S42, using the surplus peak-shaving and frequency-modulating electricity to power the peak-shaving and frequency-modulating electric heater of the solid thermal storage electric boiler (9), and using electric heating to make the solid thermal storage brick (18) reach its thermal storage temperature; S43, opening the heating flue gas outlet valve of the flue gas heat exchanger, and allowing the high-temperature flue gas from the power station boiler to enter the heat release gas inlet valve of the high-temperature flue gas heat exchanger and then be discharged from the outlet valve back to the flue of the power station boiler; the solid heat storage bricks (18) in the solid heat storage electric boiler (9) absorb the heat of the high-temperature flue gas and reach their heat storage temperature; S44, opening the heating steam inlet valve and outlet valve of the high-temperature steam heat exchanger, and the high-temperature steam drawn from the main steam, reheated steam or steam extraction of the power plant boiler enters the high-temperature steam heat exchanger to release heat, and then is discharged from the outlet valve back to the thermal system of the thermal power plant; the solid heat storage bricks (18) in the solid heat storage electric boiler (9) absorb the heat of the high-temperature steam and reach their heat storage temperature; S5. The steam generated by the solid thermal storage electric boiler (9) is fed into the large steam turbine of the thermal power plant to drive the generator to increase the power generation, thereby increasing the peak capacity of the thermal power plant during the peak period of power demand and reducing the use of coal in its power station boiler.

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