Coal-fired unit and electric boiler combined peak shaving system and peak shaving method

Abstract

The invention relates to the technical field of peak regulation of cogeneration units, in particular to a coal-fired unit and electric boiler combined peak regulation system and method. The system comprises a coal-fired unit steam-water module and a peak shaving module. The coal-fired unit steam-water module comprises a coal-fired boiler, a steam turbine and a condensed water treatment unit, a steam outlet of the coal-fired boiler is connected with the steam turbine, a steam exhaust port of the steam turbine is connected with the condensed water treatment unit, and a water outlet of the condensed water treatment unit is connected with the coal-fired boiler. The peak regulation module comprises a heat storage unit and a heat exchange unit, the heat storage unit comprises a generator, an electric boiler and a water storage tank, a first water circulation unit is arranged between the electric boiler and the water storage tank, and the water storage tank is connected with the condensed water treatment unit through the heat exchange unit. The electric boiler is used for peak regulation, heat stored in the water storage tank is converted into heat of condensation water, space-time transfer of electric quantity is achieved in the non-heat-supply season, the utilization rate of equipment is increased, and the income of a power plant is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of peak shaving for combined heat and power units, in particular to a combined peak shaving system and method for a coal-fired unit and an electric boiler. Background Art

[0002] Currently, combined heat and power units are the main heating heat sources in northern cities in winter. The rapidly growing heating demand in urban development and construction makes the heat load of the units in the heating season often at a relatively high level. Due to the inherent constraints of thermoelectric coupling in combined heat and power units, the electric output of the units in the heating season is relatively high. In winter, the wind resources in the northern region are rich, and the power generation of new energy such as wind power is high, which brings great difficulties to the consumption of new energy. Therefore, each power generation enterprise has successively taken a series of measures to decouple heat and electricity in combined heat and power units, and on the basis of ensuring the heating needs of the people's livelihood, reduce the power generation output of the units to make the units have flexible peak shaving capabilities.

[0003] Some power generation enterprises have adopted the technical route of electric boiler peak shaving, that is, installing high-power electro-thermal conversion equipment on the side of combined heat and power units, using the self-provided power in the factory, and converting the deeply peak-shaved power of the factory into heat energy before the gateway meter, which can effectively solve the contradiction between grid peak shaving and ensuring the supply of people's livelihood, and resolve the problems of wind abandonment and light abandonment in the "Three-North" regions. However, currently, the additional installation of electric boilers in power plants is only used for heat and electricity decoupling in the heating season, and the equipment is shut down in the non-heating season, resulting in low equipment utilization rate.

[0004] With the rapid development of new energy power such as wind and light, the demand for flexible regulation of coal-fired units for the safe and stable operation of the power system is more urgent. Currently, power spot trading markets have been implemented in multiple regional power grids, and the force of forcing coal power to further improve its flexible power generation capacity through the power spot trading market will be greater. How to improve profitability under the rules of the power spot trading market is a practical problem faced by power generation enterprises. Summary of the Invention

[0005] The technical problem to be solved by the embodiments of the present invention is to provide a combined peak shaving system and method for a coal-fired unit and an electric boiler to solve the problems of low utilization rate and low income of combined heat and power units in power plants in the non-heating season in the prior art.

[0006] The present invention discloses a combined peak shaving system for a coal-fired unit and an electric boiler, including: A steam and water module of the coal-fired unit, including a coal-fired boiler, a steam turbine, a generator, and a condensate treatment unit. The steam outlet of the coal-fired boiler is connected to the steam turbine, the exhaust port of the steam turbine is connected to the condensate treatment unit, and the extraction port of the steam turbine is connected to the condensate treatment unit, so that the exhaust steam of the steam turbine enters the condensate treatment unit to be condensed into condensate, and is heated by the steam extracted from the steam turbine. The water outlet of the condensate treatment unit is connected to the coal-fired boiler; The peak shaving module includes a heat storage unit and a heat exchange unit. The heat storage unit includes an electric boiler and a water storage tank. The generator is connected to the work output end of the steam turbine, and the generator is electrically connected to the electric boiler. A first water circulation unit is arranged between the electric boiler and the water storage tank, and the water storage tank is connected to the condensate treatment unit through the heat exchange unit.

[0007] Optionally, the first water circulation unit includes a first hot water delivery pipeline and a first cold water delivery pipeline. The first hot water delivery pipeline and the first cold water delivery pipeline are respectively connected to the electric boiler and the water storage tank, and a cold water pump is arranged on the first cold water delivery pipeline; A first valve is arranged on the first hot water delivery pipeline, and a second valve is arranged on the first cold water delivery pipeline.

[0008] Optionally, the heat exchange unit includes a heat exchanger, a second hot water delivery pipeline, a second cold water delivery pipeline and a hot water pump. One end of the second hot water delivery pipeline is connected to the water outlet of the water storage tank, and the other end of the second hot water delivery pipeline is connected to the shell side inlet of the heat exchanger. The hot water pump is arranged on the second hot water delivery pipeline. One end of the second cold water delivery pipeline is connected to the water inlet of the water storage tank, and the other end of the second cold water delivery pipeline is connected to the shell side outlet of the heat exchanger.

[0009] Optionally, a third valve is arranged on the second hot water delivery pipeline, and a fourth valve is arranged on the second cold water delivery pipeline.

[0010] Optionally, the condensate treatment unit includes a condenser and a condensate heater. The exhaust port of the steam turbine, the condenser and the condensate inlet of the condensate heater are connected in sequence, and the extraction port of the steam turbine is connected to the heating steam inlet of the condensate heater; The heat exchange unit further includes a third hot water delivery pipeline and a third cold water delivery pipeline. One end of the third cold water delivery pipeline is connected to the pipeline between the condensate heater and the condenser, and the other end of the third cold water delivery pipeline is connected to the tube side inlet of the heat exchanger. One end of the third hot water delivery pipeline is connected to the tube side outlet of the heat exchanger, and the other end of the third hot water delivery pipeline is connected to the water return port of the condensate heater.

[0011] Optionally, the condensate treatment unit further includes a condensate pump. The exhaust port of the steam turbine, the condenser, the condensate pump and the condensate inlet of the condensate heater are connected in sequence; A fifth valve is provided on the connecting pipeline between the condensate pump and the condensate heater, a sixth valve is provided on the third hot water delivery pipeline, and a seventh valve is provided on the third cold water delivery pipeline.

[0012] Optionally, the steam-water module of the coal-fired unit further includes a feed water pump and a feed water heater. The condensate outlet of the condensate heater, the feed water pump, the feed water heater, and the water return port of the coal-fired boiler are connected in sequence, and the extraction port of the steam turbine is connected to the heating steam inlet of the feed water heater.

[0013] Optionally, the steam-water module of the coal-fired unit further includes a deaerator. The condensate outlet of the condensate heater, the deaerator, and the feed water pump are connected in sequence, and the extraction port of the steam turbine is connected to the heating steam inlet of the deaerator.

[0014] Optionally, the combined peak shaving system of the coal-fired unit and the electric boiler further includes a heat network circulation unit. The heat network circulation unit includes a heat network supply water pipeline and a heat network return water pipeline. One end of the heat network supply water pipeline is connected to the water inlet of the electric boiler, and the other end of the heat network supply water pipeline is connected to the hot water pipe network. An eighth valve is provided on the heat network supply water pipeline. One end of the heat network return water pipeline is connected to the water outlet of the electric boiler, and the other end of the heat network supply water pipeline is connected to the hot water pipe network. A ninth valve is provided on the heat network return water pipeline.

[0015] The present invention also discloses a peak shaving method, which uses the above-mentioned combined peak shaving system of the coal-fired unit and the electric boiler, and includes: Controlling the outlet steam of the coal-fired boiler to enter the steam turbine to expand and do work. After the exhaust steam of the steam turbine is condensed by the condensate treatment unit, controlling a part of the steam in the steam turbine to be extracted to heat the condensate, and the heated condensate returns to the coal-fired boiler; In response to the low electricity price period of the power grid in the non-heating season, the generator supplies power to the electric boiler, and the aqueous solution in the water storage tank enters the electric boiler through the first water circulation unit to be heated, and controlling the heated aqueous solution to return to the water storage tank; In response to the high electricity price period of the power grid in the non-heating season, the heated aqueous solution in the water storage tank and the condensate in the condensate treatment unit exchange heat in the heat exchange unit, and controlling the heated condensate to return to the condensate treatment unit to displace the steam drawn in.

[0016] Compared with the prior art, the beneficial effects of the combined peak shaving system and the peak shaving method of the coal-fired unit and the electric boiler provided by the embodiments of the present invention are as follows: By setting up the steam-water module and peak shaving module of the coal-fired unit, the outlet steam of the coal-fired boiler is controlled to enter the steam turbine for expansion work, so that the steam turbine drives the generator to generate electricity. The exhaust steam of the steam turbine is controlled to be condensed through the condensate treatment unit, and the condensate is heated by the steam extracted from the steam turbine, so that the heated condensate returns to the coal-fired boiler for reheating to generate steam, so as to complete the steam-water cycle of the coal-fired power generation unit. When it is in the non-heating season, during the low electricity price period of the power grid, the electric boiler is used to consume part of the electricity of the generator to heat the circulating water led out from the water storage tank and return it to the water storage tank for storage, so as to reduce the grid-connected electricity of the steam-water module of the coal-fired unit during the low electricity price period; during the high electricity price period of the power grid, the heated aqueous solution in the water storage tank and the condensate in the condensate treatment unit are heat-exchanged in the heat exchange unit, and the heated condensate is controlled to return to the condensate treatment unit, so as to convert the heat stored in the water storage tank into condensate heat, thereby displacing the extraction steam originally used to heat the condensate in the condensate treatment unit, so that the displaced extraction steam still continues to do work in the steam turbine, improving the external power generation of the steam-water module of the coal-fired unit. Thus, the time-space transfer of electricity is realized through the electric boiler in the non-heating season, that is, the utilization rate of the equipment in the non-heating season is improved, and the power plant revenue is also increased by realizing the "low storage and high release" of electricity. Brief Description of the Drawings

[0017] The technical solutions of the present invention will be further described in detail below in conjunction with the drawings and embodiments. In the drawings: Figure 1 It is a schematic diagram of the overall structure of the combined peak shaving system of the coal-fired unit and the electric boiler provided by the embodiment of the present invention.

[0018] Each reference numeral in the figure is: 1. Steam-water module of coal-fired unit; 11. Coal-fired boiler; 12. Steam turbine; 13. Generator; 14. Condensate treatment unit; 141. Condenser; 142. Condensate heater; 15. Feed water pump; 16. Feed water heater; 17. Deaerator; 2. Peak shaving module; 21. Electric boiler; 22. Water storage tank; 23. Heat exchange unit; 231. Heat exchanger; 232. Second hot water delivery pipeline; 2321. Third valve; 233. Second cold water delivery pipeline; 2331. Fourth valve; 234. Hot water pump; 235. Third hot water delivery pipeline; 2351. Sixth valve; 236. Third cold water delivery pipeline; 2361. Seventh valve; 24. First hot water delivery pipeline; 241. First valve; 25. First cold water delivery pipeline; 251. Second valve; 26. Cold water pump; 27. Fifth valve; 3. Heat network supply water pipeline; 31. Eighth valve; 4. Heat network return water pipeline; 41. Ninth valve. Detailed Embodiments

[0019] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. Now, in conjunction with the accompanying drawings, detailed description will be given to the preferred embodiments of the present invention.

[0020] The present invention discloses a combined peak shaving system for a coal-fired unit and an electric boiler, as Figure 1 shown, which includes a steam-water module 1 of the coal-fired unit and a peak shaving module 2. The steam-water module 1 of the coal-fired unit includes a coal-fired boiler 11, a steam turbine 12, a generator 13, and a condensate treatment unit 14. The steam outlet of the coal-fired boiler 11 is connected to the steam turbine 12. The exhaust port of the steam turbine 12 is connected to the condensate treatment unit 14, and the extraction port of the steam turbine 12 is also connected to the condensate treatment unit 14, so that the exhaust steam of the steam turbine 12 enters the condensate treatment unit 14 to be condensed into condensate, and is heated by the steam extracted from the steam turbine 12 through heat exchange. The water outlet of the condensate treatment unit 14 is connected to the coal-fired boiler 11. The peak shaving module 2 includes a heat storage unit and a heat exchange unit 23. The heat storage unit includes an electric boiler 21 and a water storage tank 22. The generator 13 is connected to the power output end of the steam turbine 12, and the generator 13 is electrically connected to the electric boiler 21. A first water circulation unit is provided between the electric boiler 21 and the water storage tank 22, and the water storage tank 22 is connected to the condensate treatment unit 14 through the heat exchange unit 23.

[0021] Through the implementation of the above embodiments of the combined peak shaving system of the coal-fired unit and the electric boiler, the outlet steam of the coal-fired boiler 11 is controlled to enter the steam turbine 12 for expansion work, so that the work done by the steam turbine 12 directly drives the generator 13 to generate electricity. The exhaust steam during the work process of the steam turbine 12 is introduced into the condensate treatment unit 14 for condensation. Thus, by recovering the condensate, the makeup water volume of the coal-fired boiler 11 is reduced, and the efficiency of the entire thermal cycle is improved. Since the thermal energy of the condensed condensate is relatively low, a part of the steam extracted from the steam turbine 12 is used to heat the condensate to increase its temperature, and the heated condensate is returned to the coal-fired boiler 11 for reheating to generate steam, which can effectively reduce the heating time in the coal-fired boiler 11, reduce the load of the coal-fired boiler 11, and thus complete the steam-water cycle of the coal-fired generator 13 set. When it is in the non-heating season, during the low electricity price period of the power grid, the generator 13 is used to drive the electric boiler 21 to operate, so that the electric boiler 21 consumes part of the electricity of the generator 13 to heat the circulating water led out from the water storage tank 22, and the heated aqueous solution is returned to the water storage tank 22 for storage, and the heating of the aqueous solution in the water storage tank 22 is stopped at the end of the low electricity price period to reduce the grid-connected electricity volume of the steam-water module 1 of the coal-fired unit during the low electricity price period. During the high electricity price period of the power grid, the heated aqueous solution in the water storage tank 22 and the condensate in the condensate treatment unit 14 are heat-exchanged in the heat exchange unit 23, and the heated condensate is controlled to return to the condensate treatment unit 14, so as to convert the heat stored in the water storage tank 22 into condensate heat, thereby displacing the extraction steam originally used to heat the condensate in the condensate treatment unit 14, and enabling the displaced extraction steam to continue to do work in the steam turbine 12, increasing the external power generation of the steam-water module 1 of the coal-fired unit. That is, less electricity is generated during the low electricity price period and more electricity is generated during the high electricity price period. Thus, through the electric boiler 21, the time-space transfer of electricity is realized in the non-heating season, which not only improves the utilization rate of the equipment in the non-heating season, but also improves the power plant's revenue by realizing the "low storage and high release" of electricity.

[0022] Further, the first water circulation unit includes a first hot water delivery pipeline 24 and a first cold water delivery pipeline 25. The first hot water delivery pipeline 24 and the first cold water delivery pipeline 25 are respectively connected to the electric boiler 21 and the water storage tank 22, and a cold water pump 26 is provided on the first cold water delivery pipeline 25. A first valve 241 is provided on the first hot water delivery pipeline 24, and a second valve 251 is provided on the first cold water delivery pipeline 25.

[0023] Through the implementation of the above embodiments of the combined peak shaving system of the coal-fired unit and the electric boiler, using the first cold water delivery pipeline 25 and the cold water pump 26, the aqueous solution in the water storage tank 22 is delivered into the electric boiler 21 to be heated, and the heated aqueous solution returns to the water storage tank 22 along the first hot water delivery pipeline 24 for storage. In addition, by setting the first valve 241 and the second valve 251, independent delivery of cold water and heated water between the water storage tank 22 and the electric boiler 21 can be achieved, so as to optimize the heating efficiency of the aqueous solution in the water storage tank 22. Specifically, the first valve 241 and the second valve 251 are opened during the low electricity price period of the power grid, and the first valve 241 and the second valve 251 are closed at the end of the low electricity price period, reducing the on-grid power of the steam-water module 1 of the coal-fired unit during the low electricity price period.

[0024] Furthermore, the heat exchange unit 23 includes a heat exchanger 231, a second hot water delivery pipeline 232, a second cold water delivery pipeline 233, and a hot water pump 234. One end of the second hot water delivery pipeline 232 is connected to the water outlet of the water storage tank 22, and the other end of the second hot water delivery pipeline 232 is connected to the shell-side inlet of the heat exchanger 231. The hot water pump 234 is arranged on the second hot water delivery pipeline 232. One end of the second cold water delivery pipeline 233 is connected to the water inlet of the water storage tank 22, and the other end of the second cold water delivery pipeline 233 is connected to the shell-side outlet of the heat exchanger 231.

[0025] Furthermore, a third valve 2321 is arranged on the second hot water delivery pipeline 232, and a fourth valve 2331 is arranged on the second cold water delivery pipeline 233.

[0026] Furthermore, the condensate treatment unit 14 includes a condenser 141 and a condensate heater 142. The exhaust port of the steam turbine 12, the condenser 141, and the condensate inlet of the condensate heater 142 are connected in sequence. The extraction port of the steam turbine 12 is connected to the heating steam inlet of the condensate heater 142; The heat exchange unit 23 further includes a third hot water delivery pipeline 235 and a third cold water delivery pipeline 236. One end of the third cold water delivery pipeline 236 is connected to the pipeline between the condensate heater 142 and the condenser 141, and the other end of the third cold water delivery pipeline 236 is connected to the tube-side inlet of the heat exchanger 231. One end of the third hot water delivery pipeline 235 is connected to the tube-side outlet of the heat exchanger 231, and the other end of the third hot water delivery pipeline 235 is connected to the water return port of the condensate heater 142.

[0027] Furthermore, the condensate treatment unit 14 further includes a condensate pump. The exhaust port of the steam turbine 12, the condenser 141, the condensate pump, and the condensate inlet of the condensate heater 142 are connected in sequence; A fifth valve 27 is provided on the connecting pipeline between the condensate pump and the condensate heater 142, a sixth valve 2351 is provided on the third hot water delivery pipeline 235, and a seventh valve 2361 is provided on the third cold water delivery pipeline 236.

[0028] Through the implementation of the above embodiments of the combined peak shaving system of the coal-fired unit and the electric boiler, the low-pressure steam discharged from the steam turbine 12 is condensed into condensate by the condenser 141, and the condensate is pumped into the condensate heater 142 by the condensate pump. Since the thermal energy of the condensed condensate is relatively low, part of the steam extracted from the steam turbine 12 is used to heat the condensate in the condensate heater 142, so that the temperature of the condensate rises. The heated condensate returns to the coal-fired boiler 11 for reheating to generate steam. Thus, by recovering the condensate, the makeup water volume of the coal-fired boiler 11 is reduced, the efficiency of the entire thermal cycle is improved, and the heating time in the coal-fired boiler 11 can be effectively reduced to reduce the load of the coal-fired boiler 11.

[0029] In addition, using the heated aqueous solution in the water storage tank 22, the condensate at the outlet of the condenser 141 is introduced into the tube side of the heat exchanger 231 through the third cold water delivery pipeline 236, and the heated aqueous solution in the water storage tank 22 is introduced into the shell side of the heat exchanger 231 through the second hot water delivery pipeline 232 by the hot water pump 234, so that the heated aqueous solution in the water storage tank 22 heats the condensate in the heat exchanger 231. The heated condensate returns to the condensate heater 142 along the third hot water delivery pipeline 235, and the cooled aqueous solution returns to the water storage tank 22 along the second cold water delivery pipeline 233. Thus, the heat stored in the water storage tank 22 is converted into the heat of the condensate, so that the heated condensate returning to the condensate heater 142 displaces the steam that originally needed to be extracted from the steam turbine 12 in the condensate heater 142, and the displaced steam will still do work in the steam turbine 12 without being pumped into the condensate heater 142, greatly improving the work efficiency of the steam turbine 12, and further improving the external power generation of the generator 13, and increasing the power plant's revenue during the high electricity price period of the power grid in the non-heating season.

[0030] As described above, by setting the third valve 2321 - the seventh valve 2361, the independent transportation of the liquid in each pipeline can be realized, so as to optimize the heat exchange efficiency of converting the heat stored in the water storage tank 22 into the heat of condensate. Specifically, during the period of high electricity prices on the power grid, the third valve 2321, the fourth valve 2331, the sixth valve 2351, and the seventh valve 2361 are opened, and the fifth valve 27 is closed. The hot water pump 234 passes the heated aqueous solution in the water storage tank 22 through the second hot water delivery pipeline 232 into the shell side of the heat exchanger 231 to be heated and then returns to the condensate heater 142. And at the end of the period of high electricity prices on the power grid, the third valve 2321, the fourth valve 2331, the sixth valve 2351, and the seventh valve 2361 are closed, and the fifth valve 27 is opened to achieve the purpose of generating more electricity during the period of high electricity prices.

[0031] Furthermore, the steam-water module 1 of the coal-fired unit further includes a feed water pump 15 and a feed water heater 16. The condensate outlet of the condensate heater 142, the feed water pump 15, the feed water heater 16, and the water return port of the coal-fired boiler 11 are connected in sequence, and the extraction port of the steam turbine 12 is connected to the heating steam inlet of the feed water heater 16.

[0032] Furthermore, the steam-water module 1 of the coal-fired unit further includes a deaerator 17. The condensate outlet of the condensate heater 142, the deaerator 17, and the feed water pump 15 are connected in sequence, and the extraction port of the steam turbine 12 is connected to the heating steam inlet of the deaerator 17.

[0033] Through the implementation of the above embodiments of the combined peak shaving system of the coal-fired unit and the electric boiler, the feed water pump 15 is used to transport the heated condensate at the outlet of the condensate heater 142 into the feed water heater 16, so that the condensate is recycled as feed water into the coal-fired boiler 11 to be reheated to generate steam, so as to reduce the fuel consumption of the coal-fired boiler 11 and improve the energy utilization efficiency. And by extracting part of the steam from the steam turbine 12 to heat the feed water to further increase its temperature, and using the reheated feed water to return to the coal-fired boiler 11, the heating time in the coal-fired boiler 11 can be effectively reduced further to reduce the load of the coal-fired boiler 11. In addition, by setting the deaerator 17, the oxygen and other dissolved gases in the condensate can be effectively removed, reducing oxygen corrosion and improving the quality of the feed water, thereby protecting equipment such as the coal-fired boiler 11 and the steam turbine 12. And by connecting the heating steam inlet of the deaerator 17 to the extraction port of the steam turbine 12 and using the heat of this part of the steam to preheat the condensate, the thermal efficiency of the system is further improved.

[0034] Further, the combined peak shaving system of the coal-fired unit and the electric boiler further includes a heat network circulation unit. The heat network circulation unit includes a heat network supply water pipeline 3 and a heat network return water pipeline 4. One end of the heat network supply water pipeline 3 is connected to the water inlet of the electric boiler 21, and the other end of the heat network supply water pipeline 3 is connected to the hot water pipe network. An eighth valve 31 is provided on the heat network supply water pipeline 3. One end of the heat network return water pipeline 4 is connected to the water outlet of the electric boiler 21, and the other end of the heat network supply water pipeline 3 is connected to the hot water pipe network. A ninth valve 41 is provided on the heat network return water pipeline 4.

[0035] Through the implementation of the above embodiments of the combined peak shaving system of the coal-fired unit and the electric boiler, peak shaving can be achieved by using the electric boiler 21 during the heating season, that is, using part of the electricity of the generator 13 to drive the operation of the electric boiler 21, which can reduce the grid-connected electricity of the steam-water module 1 of the coal-fired unit and realize the deep peak shaving operation of the steam-water module 1 of the coal-fired unit. When the heat network circulating water returns from the heat network users through the heat network return water pipeline 4 and enters the electric boiler 21, the electric boiler 21 converts electricity into heat to heat the heat network circulating water and supplies it to the outside through the heat network supply water pipeline 3, so that the heat energy can be conveniently distributed to each heat network user. By using the fast start and stop of the electric boiler 21 and combining with the heat network circulation, the changes in power demand and heat load can be quickly responded to, so as to realize the peak shaving of the power grid during the heating season to meet the needs of different users. In addition, by using the settings of the eighth valve 31 and the ninth valve 41, the switching between the heat network circulation unit and the first water circulation unit can be carried out according to the heating season and the non-heating season, so that the combined peak shaving system of the embodiments of the present invention can be put into operation in any season, greatly improving the equipment utilization rate.

[0036] The present invention also discloses a peak shaving method, which adopts the above combined peak shaving system of the coal-fired unit and the electric boiler, and includes: Controlling the outlet steam of the coal-fired boiler 11 to enter the steam turbine 12 to expand and do work. After the exhaust steam of the steam turbine 12 is condensed by the condensate treatment unit 14, controlling part of the steam in the steam turbine 12 to be extracted to heat the condensate, and the heated condensate returns to the coal-fired boiler 11; In response to the low electricity price period of the power grid in the non-heating season, the steam turbine 12 does work to drive the generator 13 to generate electricity, controlling the generator 13 to start the electric boiler 21. The aqueous solution in the water storage tank 22 enters the electric boiler 21 through the first water circulation unit and is heated, and controlling the heated aqueous solution to return to the water storage tank 22; In response to the high electricity price period of the power grid in the non-heating season, the heated aqueous solution in the water storage tank 22 and the condensate in the condensate treatment unit 14 are heat-exchanged in the heat exchange unit 23, and controlling the heated condensate to return to the condensate treatment unit 14 to displace the steam drawn in.

[0037] Through the implementation of the above embodiments of the peak shaving method, the spatio-temporal transfer of electricity can be achieved in the non-heating season, realizing the "low storage and high release" of electricity, that is, generating less electricity during low electricity price periods and more electricity during high electricity price periods, which can greatly increase the revenue of the power plant and meet the operation in the non-heating season, improving the equipment utilization rate.

[0038] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. For those skilled in the art, the technical solutions recorded in the above embodiments can be modified, or some of the technical features can be equivalently replaced; and all such modifications and replacements should fall within the protection scope of the present invention.

Claims

1. A coal-fired unit and electric boiler combined peak load regulation system, characterized in that: The coal-fired unit and electric boiler combined peak-shaving system comprises: A steam-water module of a coal-fired unit, comprising a coal-fired boiler, a steam turbine, a generator, and a condensate treatment unit, wherein the steam outlet of the coal-fired boiler is connected to the steam turbine, the exhaust port of the steam turbine is connected to the condensate treatment unit, and the steam extraction port of the steam turbine is connected to the condensate treatment unit, so that the exhaust steam of the steam turbine enters the condensate treatment unit to be condensed to form condensate, and is heated by heat exchange with the steam extracted from the steam turbine, and the water outlet of the condensate treatment unit is connected to the coal-fired boiler; The peak-shaving module includes a heat storage unit and a heat exchange unit, the heat storage unit includes an electric boiler and a water storage tank, the generator is connected to the work output end of the steam turbine, and the generator is electrically connected to the electric boiler, a first water circulation unit is arranged between the electric boiler and the water storage tank, and the water storage tank and the condensate treatment unit are connected through the heat exchange unit.

2. The combined peak load regulation system of coal-fired units and electric boilers according to claim 1 is characterized in that: The first water circulation unit comprises a first hot water delivery pipeline and a first cold water delivery pipeline, the first hot water delivery pipeline and the first cold water delivery pipeline are connected to the electric boiler and the water storage tank respectively, and a cold water pump is provided on the first cold water delivery pipeline; The first hot water delivery pipeline is provided with a first valve, and the first cold water delivery pipeline is provided with a second valve.

3. The coal-fired unit and electric boiler combined peak load regulation system according to claim 1 is characterized in that: The heat exchange unit includes a heat exchanger, a second hot water delivery pipeline, a second cold water delivery pipeline and a hot water pump, one end of the second hot water delivery pipeline is connected to the water outlet of the water storage tank, and the other end of the second hot water delivery pipeline is connected to the shell side inlet of the heat exchanger, the hot water pump is arranged on the second hot water delivery pipeline, one end of the second cold water delivery pipeline is connected to the water inlet of the water storage tank, and the other end of the second cold water delivery pipeline is connected to the shell side outlet of the heat exchanger.

4. The coal-fired unit and electric boiler combined peak load regulation system according to claim 3 is characterized in that: The second hot water delivery pipeline is provided with a third valve, and the second cold water delivery pipeline is provided with a fourth valve.

5. The combined peak load regulation system of coal-fired units and electric boilers according to claim 3 is characterized in that: The condensate treatment unit comprises a condenser and a condensate heater, the exhaust port of the steam turbine, the condenser, and the condensate inlet of the condensate heater are connected in sequence, and the steam extraction port of the steam turbine is connected to the heating steam inlet of the condensate heater; The heat exchange unit also includes a third hot water delivery pipeline and a third cold water delivery pipeline, one end of the third cold water delivery pipeline is connected to the pipeline between the condensate heater and the condenser, and the other end of the third cold water delivery pipeline is connected to the pipe inlet of the heat exchanger, one end of the third hot water delivery pipeline is connected to the pipe outlet of the heat exchanger, and the other end of the third hot water delivery pipeline is connected to the return water outlet of the condensate heater.

6. The coal-fired unit and electric boiler combined peak load regulation system according to claim 5 is characterized in that: The condensate treatment unit further includes a condensate pump, and the exhaust port of the steam turbine, the condenser, the condensate pump, and the condensate inlet of the condensate heater are connected in sequence; A fifth valve is provided on the connecting pipeline between the condensate pump and the condensate heater, a sixth valve is provided on the third hot water delivery pipeline, and a seventh valve is provided on the third cold water delivery pipeline.

7. The combined peak load regulation system of coal-fired units and electric boilers according to claim 5 is characterized in that: The steam-water module of the coal-fired unit also includes a feedwater pump and a feedwater heater. The condensate outlet of the condensate heater, the feedwater pump, the feedwater heater and the return water inlet of the coal-fired boiler are connected in sequence, and the steam extraction port of the steam turbine is connected to the heating steam inlet of the feedwater heater.

8. The coal-fired unit and electric boiler combined peak load regulation system according to claim 7 is characterized in that: The steam-water module of the coal-fired unit also includes a deaerator, the condensate outlet of the condensate heater, the deaerator and the feed water pump are connected in sequence, and the steam extraction port of the steam turbine is connected to the heating steam inlet of the deaerator.

9. The coal-fired unit and electric boiler combined peak load regulation system according to claim 1, characterized in that: The coal-fired unit and electric boiler combined peak-shaving system also includes a heat network circulation unit, which includes a heat network water supply pipeline and a heat network return pipeline. One end of the heat network water supply pipeline is connected to the water inlet of the electric boiler, and the other end of the heat network water supply pipeline is connected to the hot water network, and an eighth valve is arranged on the heat network water supply pipeline, one end of the heat network return pipeline is connected to the water outlet of the electric boiler, and the other end of the heat network water supply pipeline is connected to the hot water network, and a ninth valve is arranged on the heat network return pipeline.

10. A peak load regulation method, using the coal-fired unit and electric boiler combined peak load regulation system according to any one of claims 1 to 9, characterized in that: The peak shaving method comprises: Control the outlet steam of the coal-fired boiler to enter the steam turbine to expand and do work, and after the exhaust steam of the steam turbine is condensed by the condensate treatment unit, control part of the steam in the steam turbine to be extracted to heat the condensate, and the heated condensate is returned to the coal-fired boiler; In response to a low electricity price period of the power grid during a non-heating season, the generator supplies power to the electric boiler, the aqueous solution in the water storage tank enters the electric boiler through the first water circulation unit to be heated, and the heated aqueous solution is controlled to return to the water storage tank; In response to the high electricity price period of the power grid in the non-heating season, the heated aqueous solution in the water storage tank and the condensate in the condensate treatment unit are heat exchanged in the heat exchange unit, and the heated condensate is controlled to return to the condensate treatment unit to expel the drawn-in steam.

Images