Green electricity production and storage heat utilization system capable of reducing coal electricity carbon emission intensity and capacity determination method

Abstract

The invention discloses a green power generation, storage and heat consumption system capable of reducing coal power carbon emission intensity and a capacity determination method, molten salt is used as a medium, redundant renewable energy electric power such as wind and light is converted into heat energy to be stored in the molten salt, and new energy electric power consumption is assisted. In the energy releasing stage, heat energy of the fused salt is converted into high-parameter steam, the high-parameter steam enters a high-pressure cylinder inlet or a certain-stage inlet of a steam turbine to do work to generate electricity, and the new steam amount of the coal-fired boiler is reduced. The carbon reduction effect and the proportion of the doped high-grade steam are in a positive phase relationship, and the system has the advantages of being simple, safe and reliable. The operation method of the coupling system is provided, the annual carbon reduction proportion is used as the target guide, high-proportion consumption of new energy electric power is effectively assisted, meanwhile, carbon reduction of a coal power unit can be promoted, transformation and high-quality development of coal power enterprises are assisted, and the application prospect is wide.

Description

Technical Field

[0001] The present application belongs to the technical field of reducing carbon emissions in coal-fired power generation and improving operational flexibility, and relates to a green electricity generation, storage and heat utilization system and a capacity determination method for reducing the carbon emission intensity of coal-fired power generation. Background Art

[0002] With the gradual advancement of energy transformation, the positioning and function of coal-fired power units in the power industry and industrial system are gradually changing. In the early days, the main body was electricity. With the rapid development of new energy power such as wind and solar, coal-fired power units with large installed capacity and dense geographical distribution have gradually transformed into regulation entities. They not only help the large-scale development and high-proportion consumption of renewable energy such as wind and solar with strong time-varying characteristics, but also gradually form a city solid waste consumption platform with coal-fired power as the core, and a centralized energy supply (heating for life, industrial steam, etc.) platform. With the frequent occurrence of extreme weather (high temperature, extreme cold, storms, heavy rain, etc.), the output of new energy has dropped sharply, and coal-fired power needs to peak quickly and fully. At the same time, low carbonization has become the main demand of coal-fired power in the near future. Low carbon, flexibility, efficiency, cleanliness, intelligence, and reliability are the main "performance labels" of coal-fired power in the new era.

[0003] However, the thermal cycle of coal-fired power units based on the Rankine cycle is the main way to improve cycle efficiency and reduce coal consumption (carbon emission intensity) by improving initial parameters and reducing exhaust parameters. Limited by high-temperature materials, the current highest level of initial parameters is 31MPa and 620-630℃; limited by cold source conditions, the best conditions are seawater cooling, and the turbine back pressure is about 2kPa. This is already the "ceiling" of coal-fired power, with rated load power supply coal consumption of about 260g / kWh, equivalent to a carbon emission intensity of 749g / kWh. It can be seen that there is little room to focus on the coal-fired steam-water thermal cycle to further reduce power supply energy consumption and carbon emission intensity.

[0004] Electricity generated by wind and solar power and other zero-carbon sources is called green electricity. Green electricity is used to heat the molten salt heat storage system, converting green electricity into thermal energy and storing it in the molten salt. In the energy release stage, high-temperature molten salt is used to heat the feed water of the coal-fired power unit to produce high-parameter steam, which enters the steam turbine to generate power, that is, to complete the heating and heat storage, referred to as storage. Some studies have proposed that the combustion of zero-carbon fuels such as green hydrogen, green ammonia, and biomass in boilers can reduce coal consumption while maintaining the power generation capacity of coal-fired power plants unchanged, which is equivalent to reducing coal consumption for power supply and carbon emission intensity. The key to this technical idea is that the hydrogen, ammonia and other fuels added must be zero-carbon sources (i.e. green hydrogen, green ammonia, etc.) to achieve true carbon reduction. From the perspective of the entire process chain, hydrogen, ammonia, etc. can only be produced from zero-carbon renewable electricity such as wind and solar power, which has zero-carbon properties. Through the adaptive transformation of the coal-fired power boiler combustion system and the addition of a certain proportion of zero-carbon green hydrogen, green ammonia, etc., the carbon reduction effect is positively correlated with the proportion of zero-carbon fuel added. However, there are problems such as complex process flow and large investment (taking green hydrogen as an example, it is necessary to add a hydrogen production system, a hydrogen storage system, and a hydrogen transportation system, and to carry out adaptive transformation of the boiler combustion system; in addition, hydrogen also has an explosive risk and needs to be controlled as a major hazard source). Summary of the invention

[0005] The purpose of this application is to solve the problems in the prior art and provide a green power generation, storage and heat use system and capacity determination method that reduces the carbon emission intensity of coal-fired power. The present invention provides an operation method of the coupling system, and with the annual carbon reduction ratio as the target orientation, proposes a capacity determination method for the green power generation, storage and heat use system.

[0006] In order to achieve the above objectives, this application adopts the following technical solutions: In a first aspect, the present application provides a green electricity storage and heat utilization system for reducing the carbon emission intensity of coal-fired power, comprising: A green electricity heat storage system, the green electricity heat storage system comprising a high-temperature molten salt storage tank and a low-temperature molten salt storage tank; the outlet of the high-temperature molten salt storage tank is connected to the hot side inlet of a molten salt-water heat exchanger, and the hot side outlet of the molten salt-water heat exchanger is connected to the inlet of the low-temperature molten salt storage tank; the outlet of the low-temperature molten salt storage tank is connected to the cold side inlet of a molten salt electric heater, and the cold side outlet of the molten salt electric heater is connected to the inlet of the high-temperature molten salt storage tank; the cold side of the molten salt-water heat exchanger is connected to a coal-fired steam-water thermal cycle system, and the hot side of the molten salt electric heater is connected to new energy electricity and / or coal-fired power generation unit electricity; A coal-fired power steam-water thermal cycle system, the coal-fired power steam-water thermal cycle system comprises a coal-fired boiler, a high-pressure cylinder and a low-pressure cylinder; the exhaust steam of the coal-fired boiler is connected to the steam inlet of the high-pressure cylinder, the exhaust steam of the high-pressure cylinder is connected to the low-pressure cylinder, and the exhaust steam of the low-pressure cylinder is returned to the coal-fired boiler after being heated by a heating component and a molten salt-water heat exchanger.

[0007] In a second aspect, the present application provides a capacity determination method, comprising the following steps: Determine the boundary constraints of the green electricity generation, storage and heat use system based on carbon reduction targets; Calculate the steam production load, annual operation time and single cycle heat storage time of the green electricity generation and storage heat system according to boundary constraints; The heat storage power and molten salt amount of the green electricity storage system are calculated based on the steam production load, annual operating hours and single-cycle heat storage time.

[0008] Compared with the prior art, this application has the following beneficial effects: The present invention uses molten salt as a medium to convert surplus wind and solar power and other renewable energy power into thermal energy and store it in molten salt, which helps to absorb new energy power. In the energy release stage, the thermal energy of the molten salt is converted into high-parameter steam, which enters the inlet or a certain stage of the high-pressure cylinder of the steam turbine to generate power, reduce the amount of new steam in the coal-fired boiler, and is equivalent to reducing the coal consumption of the boiler. The carbon reduction effect is positively correlated with the proportion of high-grade steam added, and has the advantages of simple system, safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0010] Figure 1 This is a schematic diagram of the process flow of the green electricity storage and heat utilization system for reducing the carbon emission intensity of coal-fired power in this application.

[0011] Among them: 1-new energy electricity, 2-coal-fired power unit electricity, 3-molten salt electric heater, 4-high-temperature molten salt storage tank, 5-high-temperature molten salt pump, 6-molten salt-water heat exchanger, 7-low-temperature molten salt tank, 8-low-temperature molten salt pump, 9-coal-fired boiler, 10-high and medium pressure cylinders, 11-low-pressure cylinder, 12-condenser, 13-condensate pump, 14-low-pressure heater group, 15-deaerator, 16-front pump, 17-feedwater pump, 18-high-pressure heater group, 19-first feedwater variable frequency booster pump, 20-first valve group, 21-second valve group, 22-second feedwater variable frequency booster pump. DETAILED DESCRIPTION

[0012] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0013] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0014] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0015] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the invented product is usually placed when used. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0016] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0017] In the description of the embodiments of the present application, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0018] The present application is further described in detail below with reference to the accompanying drawings: See also Figure 1The embodiment of the present application discloses a green electricity heat storage system for reducing the carbon emission intensity of coal-fired power, including a green electricity heat storage system and a coal-fired power steam-water thermal cycle system.

[0019] The green electricity heat storage system includes a high-temperature molten salt storage tank 4 and a low-temperature molten salt storage tank 7; the outlet of the high-temperature molten salt storage tank 4 is connected to the hot side inlet of the molten salt-water heat exchanger 6, and the hot side outlet of the molten salt-water heat exchanger 6 is connected to the inlet of the low-temperature molten salt storage tank 7; the outlet of the low-temperature molten salt storage tank 7 is connected to the cold side inlet of the molten salt electric heater 3, and the cold side outlet of the molten salt electric heater 3 is connected to the inlet of the high-temperature molten salt storage tank 4; the cold side of the molten salt-water heat exchanger 6 is connected to the coal-fired steam-water thermal cycle system, and the hot side of the molten salt electric heater 3 is connected to the new energy power 1 and / or coal-fired power 2; a high-temperature molten salt pump 5 is arranged on the pipeline between the high-temperature molten salt storage tank 4 and the molten salt-water heat exchanger 6; a low-temperature molten salt pump 8 is arranged on the pipeline between the low-temperature molten salt storage tank 7 and the molten salt electric heater 3.

[0020] The coal-fired power steam-water thermal cycle system includes a coal-fired boiler 9, a high and medium pressure cylinder 10 and a low pressure cylinder 11; the exhaust steam of the coal-fired boiler 9 is connected to the steam inlet of the high and medium pressure cylinder 10, the exhaust steam of the high and medium pressure cylinder 10 is connected to the low pressure cylinder 11, and the exhaust steam of the low pressure cylinder 11 is returned to the coal-fired boiler 9 after being heated by a heating component and a molten salt-water heat exchanger 6.

[0021] The main steam outlet of the coal-fired boiler 9 is connected to the high-pressure cylinder steam inlet of the high- and medium-pressure cylinders 10, the exhaust port of the high-pressure cylinder is connected to the reheat steam inlet of the coal-fired boiler 9 through the cold re-maining pipe, the reheat steam outlet of the coal-fired boiler 9 is connected to the intermediate-pressure cylinder steam inlet of the high- and medium-pressure cylinders 10, the exhaust port of the intermediate-pressure cylinder is connected to the steam inlet of the low-pressure cylinder 11 through a ground-pressure connecting pipe, the exhaust steam of the low-pressure cylinder 11 is returned to the coal-fired boiler 9 after being heated and pressurized by the boost heating component and the molten salt-water heat exchanger 6, completing the steam-water thermal cycle.

[0022] The boost heating assembly includes a condenser 12, a condensate pump 13, a low-pressure heater group 14, a deaerator 15, a pre-pump 16, a feed water pump 17 and a high-pressure heater group 18 which are connected in sequence. The inlet of the condenser 12 is connected to the exhaust port of the low-pressure cylinder 11, and the outlet of the high-pressure heater group 18 is connected to the steam inlet of the coal-fired boiler 9; the outlet of the pre-pump 16 is also connected to the first feed water variable frequency booster pump 19 through the first valve group 20, and the outlet of the high-pressure heater group 18 is also connected to the second feed water variable frequency booster pump 22 through the second valve group 21; the outlets of the first feed water variable frequency booster pump 19 and the second feed water variable frequency booster pump 22 are both connected to the cold side inlet of the molten salt-water heat exchanger 6; the cold side outlet of the molten salt-water heat exchanger 6 is divided into three routes, the first route is connected to the high-pressure cylinder supplementary steam port, the second route is connected to the high-pressure cylinder inlet, and the third route is used as industrial steam output.

[0023] Example In order to clearly describe the implementation process of a green electricity generation, storage and heat use system and capacity determination method proposed in this application to reduce the carbon emission intensity of coal-fired power, a 1000 MW ultra-supercritical grade, a pure condensing unit with a steam replenishment valve after the fifth stage of the high-pressure cylinder and no external heating is used as an example, and the operation process of this example is as follows. In addition, regarding the selection of molten salt medium, the three molten salt formulas that comply with GB / T36376-2018 are Hitec salt, Class I ternary salt and Class II low-melting point salt, and the operating temperature ranges are 260-560°C, 190-400°C, and 190-400°C, respectively. At this stage, Hitec salt can be selected, and the steam production parameters of the green electricity heating system can be benchmarked against the ultra-supercritical high-pressure cylinder steam replenishment parameters. After the successful development of molten salts with high parameters, wide temperature range and in compliance with national standards, the steam production parameters of the green electricity heating system can be benchmarked against the high-pressure cylinder inlet parameters.

[0024] Reference: High parameters, large capacity, full load high efficiency, high flexibility and intelligence are the development direction of new coal-fired machines. The main steam pressure of the steam turbine of the primary reheat unit is 28MPa and the temperature is 600℃, and the main steam pressure of the steam turbine of the secondary reheat unit is 32MPa and the temperature is 620℃. The steam supply position is generally after the fifth stage (1000 MW unit) or the sixth stage (600 MW unit) of the high-pressure cylinder, such as 25MPa / 600℃ / 600℃ million ultra-supercritical primary reheat units, rated steam supply parameters are 16MPa, 525℃, 280t / h; 25MPa / 600℃ / 600℃ million ultra-supercritical primary reheat units, rated steam supply parameters are 16MPa, 527℃, 160t / h; 31MPa / 605℃ / 622 / 620℃ ultra-supercritical secondary reheat units, rated steam supply parameters are basically close to those of primary reheat units.

[0025] Figure 1 This is a process system flow diagram of a green electricity heat storage system for reducing the carbon emission intensity of coal-fired power proposed in this application. Among them, new energy power 1, coal-fired power unit power 2, molten salt electric heater 3, high-temperature molten salt storage tank 4, high-temperature molten salt pump 5, molten salt-water heat exchanger 6, low-temperature molten salt tank 7 and low-temperature molten salt pump 8 constitute a green electricity heat storage system, and a coal-fired boiler 9, a high- and medium-pressure cylinder 10, a low-pressure cylinder 11, a condenser 12, a condensate pump 13, a low-pressure heater group 14, a deaerator 15, a pre-pump 16, a feed water pump 17 and a high-pressure heater group 18 are a coal-fired power steam-water thermal cycle system, and the green electricity heat storage system and the coal-fired power steam-water thermal cycle system are coupled through a first feed water variable frequency booster pump 19, a first valve group 20, a second valve group 21 and a second feed water variable frequency booster pump 22.

[0026] How this application works: (1) Separate operation of the coal-fired power steam-water thermal cycle system. The main steam generated by the coal-fired boiler 9 enters the high-pressure cylinder inlet of the high- and medium-pressure cylinders 10 to perform work. The exhaust steam enters the coal-fired boiler 9 through the cold re-maining pipe for secondary temperature increase and then enters the medium-pressure cylinder inlet of the high- and medium-pressure cylinders 10 to perform work. The exhaust steam enters the low-pressure cylinder 11 through the medium- and low-pressure connecting pipe to perform work and generate electricity. The exhaust steam enters the condenser 12 to condense into condensate and is pressurized by the condensate pump 13. It then flows through the low-pressure heater group 14, the deaerator 15, the pre-pump 16, the feed water pump 17, and the high-pressure heater 18 group in sequence and enters the boiler to complete the steam-water thermal cycle.

[0027] (2) The heat storage part of the green electricity generation and storage heat system is in operation. During the period of high-energy generation of wind and solar power, part of the surplus wind and solar power 1 is used for the molten salt electric heater 3. The cold salt (temperature of about 280°C) is driven by the low-temperature molten salt pump 8 from the low-temperature molten salt storage tank 7, enters the molten salt electric heater 3, and is heated by electricity (temperature of about 540°C) before entering the high-temperature molten salt storage tank 4 for storage. Generally speaking, the cold salt in the low-temperature molten salt storage tank 7 is emptied, while the high-temperature molten salt storage tank 4 is filled, which is called the completion of the heat storage process. In the heat release stage, generally when the output of new energy is not high, the high-temperature hot salt in the high-temperature molten salt storage tank 4 is driven by the high-temperature molten salt pump 5 and enters the molten salt-water heat exchanger 6. The outlet water of the pre-pump 16 and the high-pressure heater 18 group is pressurized by the feed water variable frequency booster pump 19 and enters the molten salt-water heat exchanger 6, absorbing the heat of the high-temperature molten salt and vaporizing it. It enters the steam supplement valve of the high-pressure cylinder of the steam turbine in the form of high parameters (16MPa, 525℃), while maintaining the output power of the steam turbine unchanged, reducing the outlet steam volume of the coal-fired boiler 9, that is, reducing the coal consumption of the coal-fired power unit. After the high-temperature molten salt releases heat in the molten salt-water heat exchanger 6, it returns to the low-temperature molten salt storage tank 7 in the form of cold salt for storage, waiting for the next cycle.

[0028] (3) The green electricity heat storage system assists the peak and frequency regulation of coal-fired power units. When the coal-fired power unit has a deep peak regulation demand, the green electricity heat storage system enters the heat storage mode and consumes the power generated by the coal-fired power unit to heat the molten salt. When the coal-fired power unit has a demand to increase the variable load rate, the molten salt electric heater 3 of the green electricity heat storage system maintains 20% power operation, and assists the coal-fired power unit in increasing the variable load rate by quickly adding or subtracting the electric heating power of the molten salt electric heater.

[0029] The embodiment of the present application also discloses a method for determining the capacity of a green electricity heat storage system. The method is guided by the annual carbon reduction ratio. The main idea of ​​determining the capacity of the green electricity heat storage system is: based on the unchanged annual power generation of coal-fired power units, determine the steam production power of the green electricity heat storage system, and then calculate the annual operating time and single cycle heat storage time of the green electricity heat storage system in turn. ， Then the molten salt reserves can be obtained. Based on this, the process system design and equipment selection of the green electricity storage and heat system can be carried out. The specific capacity determination method includes the following steps: Step 1: Based on the carbon reduction target, clarify the boundary constraints of the green electricity storage and heat use system.

[0030] The nameplate output of coal-fired power units is , in MW. The annual power generation of coal-fired power units is , in kWh. Annual operating hours , in hours. The annual weighted average coal consumption for power generation is , unit is g / kWh. Calculate the total annual standard coal consumption , in tons. Converted annual carbon dioxide emissions , unit is tons.

[0031] The annual power generation of coal-fired power units remains unchanged, and the annual carbon reduction ratio is , then the annual steam production of the green electricity storage and heat system is equal to the power generation of the steam turbine. .

[0032] Step 2: Calculate the steam generation load of the green electricity storage and heat system

[0033] The unit is at 100% 、 90% 、 80% The three output conditions are compared by using the "with and without comparison method". Without adding the heat of the green power generation and storage system, the main steam flow of the boiler under the three output conditions is obtained by running the system on site. , and , the unit is t / h.

[0034] When the heat of the green power storage system is added, the power generation of the coal-fired power unit remains unchanged at 100%. 、 90% 、 80% Three output conditions, the main steam flow of the boiler under the three output conditions reaches , and When the carbon reduction ratio of the three output conditions reaches the guidance target The steam generation load of the green electricity storage heat system is calculated As follows, the unit is t / h.

[0035]

[0036] In the formula, , and are the main steam enthalpy of the boiler under three output conditions, kJ / kg; , and are the condenser outlet water enthalpy values ​​under three output conditions, kJ / kg; , and They are the feed water enthalpy values ​​under three output conditions, kJ / kg. It is the steam production enthalpy of the green electricity storage and heat system, kJ / kg.

[0037] At this time, the steam production load of the green electricity storage and heat system can be calculated Power generation As follows, the unit is MW.

[0038]

[0039] Step 3: Calculate the annual operating time of the green electricity storage and heat system

[0040] According to the carbon reduction ratio , the annual power generation of the green electricity storage and heat system in the coal-fired power unit is calculated to be , unit is kWh.

[0041] Calculate the annual operation time of the green electricity storage and heat system as follows.

[0042]

[0043] Step 4: Calculate the single cycle heat storage time of the green electricity heat storage system

[0044] Determine the daily cycle times of the green power generation, storage and heat utilization system based on the time-varying characteristics of renewable energy output in the area where coal-fired power is located For regions rich in new energy, such as the Three Norths or coastal wind energy-rich regions, the value is 2; for other regions, the value is 1.

[0045] Note: Cycle number 1 refers to the green electricity heat storage system completing one heat storage and release cycle.

[0046] Calculate the single cycle heat storage time of the green electricity generation and storage heat system as follows

[0047] In the formula The number of days the coal-fired power unit operates each year. Points to round up.

[0048] Step 5: Calculate the heat storage power of the green electricity heat storage system and molten salt

[0049] Thermal storage power It is equal to the heat release power of the molten salt in the molten salt-water heat exchanger 6 and is calculated as follows. The unit is MW.

[0050]

[0051] It is also equal to the heat absorption power of the molten salt in the molten salt electric heater, from which the circulation flow rate of the molten salt is calculated , calculated as follows, the unit is t / h.

[0052]

[0053] In the formula, and are the enthalpy values ​​of high-temperature molten salt and low-temperature molten salt, kJ / kg respectively.

[0054] Molten salt circulation flow Multiply it by the heat storage time of a single cycle , and then take the surplus coefficient of 10%, we can get the green electricity storage and heat system , calculated as follows, in tons.

[0055]

[0056] This application provides an operating method for the coupling system, and with the annual carbon reduction ratio as the goal orientation, proposes a capacity determination method for the green electricity storage and heat system. While effectively assisting in the high-proportion consumption of new energy electricity, this application can also promote carbon reduction in coal-fired power units, assist in the transformation and high-quality development of coal-fired power companies, and has broad application prospects.

[0057] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A green electricity storage and heat system that reduces the carbon emission intensity of coal-fired power, characterized in that: include: A green electricity heat storage system, the green electricity heat storage system comprising a high-temperature molten salt storage tank (4) and a low-temperature molten salt storage tank (7); the outlet of the high-temperature molten salt storage tank (4) is connected to the hot side inlet of a molten salt-water heat exchanger (6), and the hot side outlet of the molten salt-water heat exchanger (6) is connected to the inlet of the low-temperature molten salt storage tank (7); the outlet of the low-temperature molten salt storage tank (7) is connected to the cold side inlet of a molten salt electric heater (3), and the cold side outlet of the molten salt electric heater (3) is connected to the inlet of the high-temperature molten salt storage tank (4); the cold side of the molten salt-water heat exchanger (6) is connected to a coal-fired power steam-water thermal cycle system, and the hot side of the molten salt electric heater (3) is connected to new energy power (1) and / or coal-fired power generation unit power (2); A coal-fired power steam-water thermal cycle system, the coal-fired power steam-water thermal cycle system comprising a coal-fired boiler (9), a high and medium pressure cylinder (10) and a low-pressure cylinder (11); the exhaust steam of the coal-fired boiler (9) is connected to the steam inlet of the high and medium pressure cylinder (10), the exhaust steam of the high and medium pressure cylinder (10) is connected to the low-pressure cylinder (11), and the exhaust steam of the low-pressure cylinder (11) is returned to the coal-fired boiler (9) after being heated by a heating component and a molten salt-water heat exchanger (6).

2. The green electricity storage and heat utilization system for reducing the carbon emission intensity of coal-fired power according to claim 1 is characterized in that: A high-temperature molten salt pump (5) is provided on the pipeline between the high-temperature molten salt storage tank (4) and the molten salt-water heat exchanger (6); and a low-temperature molten salt pump (8) is provided on the pipeline between the low-temperature molten salt storage tank (7) and the molten salt electric heater (3).

3. The green electricity heat storage and utilization system for reducing the carbon emission intensity of coal-fired power according to claim 1 is characterized in that: The main steam outlet of the coal-fired boiler (9) is connected to the high-pressure cylinder steam inlet of the high- and medium-pressure cylinders (10); the exhaust port of the high-pressure cylinder is connected to the reheat steam inlet of the coal-fired boiler (9) through a cold reheating main pipe; the reheat steam outlet of the coal-fired boiler (9) is connected to the medium-pressure cylinder steam inlet of the high- and medium-pressure cylinders (10); the exhaust port of the medium-pressure cylinder is connected to the steam inlet of the low-pressure cylinder (11) through a medium- and low-pressure connecting pipe; the exhaust steam of the low-pressure cylinder (11) is heated and pressurized by a booster heating component and a molten salt-water heat exchanger (6) and then returns to the coal-fired boiler (9), completing the steam-water thermal cycle.

4. The green electricity storage and heat system for reducing the carbon emission intensity of coal-fired power according to claim 3 is characterized in that: The boost heating assembly comprises a condenser (12), a condensate pump (13), a low-pressure heater group (14), a deaerator (15), a pre-pump (16), a feed water pump (17) and a high-pressure heater group (18) which are connected in sequence, the inlet of the condenser (12) being connected to the exhaust port of the low-pressure cylinder (11), and the outlet of the high-pressure heater group (18) being connected to the steam inlet of the coal-fired boiler (9); The outlet of the pre-pump (16) is also connected to the first water supply variable frequency booster pump (19) through the first valve group (20), and the outlet of the high-pressure heater group (18) is also connected to the second water supply variable frequency booster pump (22) through the second valve group (21); the outlets of the first water supply variable frequency booster pump (19) and the second water supply variable frequency booster pump (22) are both connected to the cold side inlet of the molten salt-water heat exchanger (6); the cold side outlet of the molten salt-water heat exchanger (6) is divided into three paths, the first path is connected to the high-pressure cylinder supplementary steam port, the second path is connected to the high-pressure cylinder inlet, and the third path is used as industrial steam supply output.

5. A method for determining the capacity of the system according to any one of claims 1 to 4, characterized in that: The following steps are involved: Determine the boundary constraints of the green electricity generation, storage and heat use system based on carbon reduction targets; Calculate the steam production load, annual operation time and single cycle heat storage time of the green electricity generation and storage heat system according to boundary constraints; The heat storage power and molten salt amount of the green electricity storage system are calculated based on the steam production load, annual operating hours and single-cycle heat storage time.

6. The capacity determination method according to claim 5, characterized in that: Determining the boundary constraints of the green electricity storage and heat utilization system includes: The annual steam production of the green electricity storage and heat system is equivalent to the power generation of the steam turbine: in, is the annual power generation of coal-fired power units, is the annual carbon reduction ratio.

7. The capacity determination method according to claim 6, characterized in that: The steam production load is calculated as follows: The unit is at 100% 、 90% 、 80% The main steam flow of the boiler under the three output conditions was obtained by using the "with and without comparison method" without adding the heat of the green power generation and storage system through on-site operation of the system. , and , the unit is t / h; When the heat of the green power storage system is added, the power generation capacity of the coal-fired power unit is maintained at 100%. 、 90% 、 80% The three output conditions remain unchanged, and the main steam flow of the boiler under the three output conditions reaches , and When the carbon reduction ratio of the three output conditions reaches the annual carbon reduction ratio of the guiding target ; From this, the steam production load of the green electricity storage and heat system is calculated as follows: In the formula, , and are the main steam enthalpy values ​​of the boiler under three output conditions; , and They are the condenser outlet water enthalpy values ​​under three output conditions; , and They are the feed water enthalpy values ​​under three output conditions; is the steam production enthalpy of the green electricity storage and heat system; At this time, the steam production load of the green electricity storage and heat system can be calculated Power generation capacity: in, Steam generation load for green electricity storage and heat system The power generation capacity, Contribute to the nameplate of coal-fired power units.

8. The capacity determination method according to claim 7, characterized in that: The annual operating hours are calculated as follows: in, The annual operating time of the green electricity storage and heat system.

9. The capacity determination method according to claim 8, characterized in that: The calculation method of the single cycle heat storage time is as follows: in, The single cycle heat storage time of the green electricity heat storage system. Points to the integer upwards, is the annual operating days of coal-fired power units, It is the daily cycle number of the green electricity storage and heat system.

10. The capacity determination method according to claim 9, characterized in that: The calculation method of the heat storage power and molten salt amount of the green electricity heat storage system is as follows: The heat storage power is as follows: in, is the heat storage power; The circulation flow is as follows: in, is the circulation flow, and are the enthalpy values ​​of high temperature molten salt and low temperature molten salt respectively; The amount of molten salt in the green electricity storage heat system is as follows: in, The amount of molten salt used in the green electricity storage and heat system.

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