Flexible peak regulation and steam supply system for thermal power

Abstract

A flexible peak regulation and steam supply system for thermal power comprises a steam turbine unit, a compressor unit and an energy storage system. The steam turbine set comprises a boiler and a steam turbine, and the steam turbine is connected with and drives a power generator to generate power; the number of the compressor units is one or more, each compressor unit comprises a motor and a compressor, and after low-pressure saturated steam output by the steam turbine enters the compressors, the low-pressure saturated steam is pressurized and heated to generate high-temperature and high-pressure steam; the energy storage system comprises a high-temperature storage tank and a low-temperature storage tank and is used for storing heat energy in high-temperature and high-pressure steam generated by the compressor. The system has the advantages of being high in heating efficiency, simple in system operation, high in system flexibility and safe.

Description

Technical Field

[0001] The utility model relates to the technical field of energy, and in particular to a system for flexible peak regulation and steam supply for thermal power. Background Art

[0002] In recent years, the photovoltaic and wind power fields have developed vigorously, but with the changeable weather conditions, the stability of the power grid has also been greatly affected. Therefore, thermal power units are needed as base load power sources, and they are transformed for flexibility. When photovoltaic and wind power are generated, active load reduction is currently the most effective means to stabilize the volatility of the power grid. At present, the means of transforming the flexibility of thermal power include turbine bypass transformation, low-load boiler stable combustion technology, high-temperature heat pump molten salt energy storage technology, electric heating molten salt energy storage technology, etc., but they all have their own shortcomings. For example, turbine bypass transformation and boiler stable combustion technology cannot reduce the power generation of thermal power units to zero, the electric heating molten salt energy storage technology has an electric-to-electric conversion efficiency of less than 50%, and the electric-to-electric conversion efficiency of high-temperature heat pump molten salt energy storage technology is slightly higher, about 60%, but the system operation is complex, the initial investment of equipment is high, and the main steam pipeline needs to be modified, which affects the operation safety of the power plant itself.

[0003] Steam is the "blood" of industry. It is widely used in various manufacturing industries such as petroleum, chemical, electric power, machinery, textile, metallurgy, food, and pharmaceuticals. At present, for steam supply, most people use coal-to-steam. However, due to the continuous rise in coal prices in recent years and the difficulty in obtaining new coal-burning indicators, there are many technologies for electric steam generation, such as high-temperature heat pump technology and heat pump steam unit technology, but they all have their own defects, such as low COP of high-temperature heat pump technology and inability of heat pump steam unit technology to store energy. In summary, the industry is in urgent need of a new type of system that can be used for both thermal power peak regulation and industrial steam supply, and it needs to be more flexible in thermal power peak regulation. Utility Model Content

[0004] In view of the deficiencies in the prior art, the utility model provides a system for flexible peak regulation and steam supply of thermal power, which has the advantages of high heating efficiency, simple system operation, high system flexibility and safety.

[0005] The above technical objectives of the utility model are achieved through the following technical solutions:

[0006] A system for flexible peak regulation and steam supply of thermal power, characterized by comprising a steam turbine unit, a compressor unit and an energy storage system;

[0007] Steam turbine unit: includes a boiler and a steam turbine, the steam turbine is connected to and drives a generator to generate electricity;

[0008] Compressor unit: The compressor unit is provided in one or more groups, each of which includes an electric motor and a compressor. The low-pressure saturated steam output by the steam turbine enters the compressor and is pressurized and heated to generate high-temperature and high-pressure steam. The compressor is further connected to the steam turbine. The high-temperature and high-pressure steam generated after pressurization and heating is introduced into the steam turbine together with the high-temperature and high-pressure steam generated in the boiler for power generation;

[0009] Energy storage system: includes high-temperature storage tanks and low-temperature storage tanks, which are used to store the thermal energy in the high-temperature and high-pressure steam generated by the compressor.

[0010] Furthermore, when the compressor unit is configured as a group, the compressor is also connected to a first heat exchanger, and the high-temperature and high-pressure steam after heat exchange is incorporated into the industrial steam supply network, and the first heat exchanger is connected to a high-temperature storage tank and a low-temperature storage tank.

[0011] Furthermore, when the compressor group is set to multiple groups, the multiple compressor groups are connected in series to form a multi-stage compressor group, each compressor group is connected to a first heat exchanger, and the high-temperature and high-pressure steam after heat exchange is incorporated into the industrial steam supply network. Several of the first heat exchangers are connected to high-temperature storage tanks and low-temperature storage tanks at the same time.

[0012] Furthermore, when the compressor groups are arranged as multiple groups, the multiple compressor groups are connected in parallel, each compressor group is respectively connected to a first heat exchanger or all the compressor groups are connected to the same first heat exchanger, and the high-temperature and high-pressure steam after heat exchange is incorporated into the industrial steam supply network, and the first heat exchanger is connected to a high-temperature storage tank and a low-temperature storage tank.

[0013] Furthermore, the high-temperature storage tank and the low-temperature storage tank are also commonly connected to a second heat exchanger, and the second heat exchanger generates high-temperature and high-pressure steam after being fed with water, and is incorporated into the industrial steam supply network.

[0014] Furthermore, the high-temperature storage tank and the low-temperature storage tank are also commonly connected to a second heat exchanger, which generates high-temperature and high-pressure steam after being fed with water, and then further pressurized and heated, and then merged into the steam pipe from the boiler to the turbine.

[0015] Furthermore, the steam turbine unit also includes a condenser and a feed water pump. The condenser is connected to the steam turbine. The condenser converts the low-temperature and low-pressure steam output by the steam turbine into liquid water, which is input into the boiler together with the feed water from the feed water pump.

[0016] Furthermore, the high-temperature storage tank and the low-temperature storage tank are molten salt storage tanks.

[0017] The utility model has the following beneficial effects:

[0018] 1. The utility model proposes a system with a wider application range and richer functions, which can be used for flexible peak regulation of thermal power and industrial steam supply.

[0019] 2. The system provided by the utility model greatly improves the heating efficiency and economy. At the same time, due to the addition of a molten salt energy storage device as a flexible energy source, the difficulty of the compressor to adapt to different loads is reduced.

[0020] 3. The system provided by the utility model has a simple structure and operation, low equipment investment cost, and does not require modification of the main steam pipeline of the thermal power plant. It is safer and has good practical feasibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of Example 1 of the utility model;

[0022] Figure 2 It is a schematic diagram of Example 2 of the present utility model;

[0023] Figure 3 This is a schematic diagram of Example 3 of the present utility model. DETAILED DESCRIPTION

[0024] The technical solution of the present utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0025] Embodiment 1:

[0026] A system for flexible peak regulation and steam supply for thermal power generation, including a steam turbine unit, a compressor unit and an energy storage system. The steam turbine unit includes a boiler and a steam turbine. The high-temperature and high-pressure gas generated by the boiler is used to drive the steam turbine. The steam turbine is connected to a generator and drives the generator to generate electricity. At the same time, the steam turbine is also connected to a condenser. After the high-temperature and high-pressure steam in the thermal power plant expands and works through the steam turbine, the low-pressure saturated steam with a large amount of latent heat enters the condenser, thereby converting the low-temperature and low-pressure steam into liquid water and passing it into the feed water pump of the thermal power plant and finally into the boiler.

[0027] The compressor unit includes an electric motor and a compressor. In this embodiment, multiple compressor units are provided to form a multi-stage compressor unit. Figure 1 As shown, there are three compressor groups, including motor A and compressor A, motor B and compressor B, motor C and compressor C, and the compressor groups are connected in series, that is, compressor A, compressor B and compressor C are connected in sequence, and the low-pressure saturated steam discharged from the turbine is first introduced into compressor A.

[0028] Each compressor is connected to a corresponding first heat exchanger, and the steam is heated and pressurized in the compressor to form high-temperature and high-pressure steam, and then heat is exchanged in the first heat exchanger. Each first heat exchanger is connected to an energy storage system, which includes a high-temperature storage tank and a low-temperature storage tank. In this embodiment, the high-temperature storage tank and the low-temperature storage tank are molten salt storage tanks, that is, hot salt tanks and cold salt tanks, which are used to store the heat energy in the high-temperature and high-pressure steam generated by the compressor.

[0029] In this embodiment, the first heat exchanger includes heat exchanger A, heat exchanger B and heat exchanger C. That is, compressor A is connected to heat exchanger A, heat exchanger A is connected to compressor B, compressor B is connected to heat exchanger B, heat exchanger B is connected to compressor C, and compressor C is connected to heat exchanger C. Heat exchanger A, heat exchanger B and heat exchanger C are all connected to the hot salt tank and the cold salt tank.

[0030] The hot salt tank and the cold salt tank are also connected to a second heat exchanger. In this embodiment, the second heat exchanger is heat exchanger D. Water is supplied at heat exchanger D. At this time, a large amount of thermal energy is stored in the energy storage system. The hot salt tank and the cold salt tank provide heat, and the water is heated to form high-temperature and high-pressure steam for incorporation into the industrial steam supply network, or combined with the high-temperature and high-pressure steam generated in the boiler and then continued to be introduced into the steam turbine for driving power generation.

[0031] The operating principle of this embodiment is as follows: after the high-temperature and high-pressure steam generated in the boiler in the thermal power plant expands through the steam turbine to do work and drives the generator to generate electricity, the low-pressure saturated steam with a large amount of latent heat first enters the compressor A for pressurization and temperature increase, and then enters the heat exchanger A for heat exchange, and the heat energy in the high-temperature and high-pressure steam is transferred to the molten salt in the energy storage device and the heat energy is stored; the high-temperature and high-pressure steam after heat exchange continues to enter the compressor B, and after pressurization and temperature increase, it is passed into the heat exchanger B for heat exchange, and the heat energy is transferred to the molten salt for storage; the high-temperature and high-pressure steam after heat exchange continues to enter the compressor C, and after pressurization and temperature increase, it is passed into the heat exchanger C for heat exchange, and the heat energy is transferred to the molten salt for storage, and the high-temperature and high-pressure steam after heat exchange is incorporated into the industrial steam supply network for industrial steam supply. After the heat exchange work of heat exchangers A, B and C, a large amount of thermal energy is stored in the energy storage system. At this time, water is supplied at heat exchanger D, and the hot salt tank and the cold salt tank are used to supply heat. The water is heated to form high-temperature and high-pressure steam for incorporation into the industrial steam supply network, or combined with the high-temperature and high-pressure steam generated in the boiler and continued to be introduced into the turbine for driving power generation.

[0032] Of course, after the high-temperature and high-pressure steam is pressurized and heated in compressor A, compressor B or compressor C, it can be directly combined with the high-temperature and high-pressure steam generated in the boiler and then continue to be introduced into the turbine to drive the generator to generate electricity.

[0033] In addition, the number of compressor groups can be adjusted according to actual needs, and the number of first heat exchangers is also changed accordingly according to the adjustment of the number of compressor groups.

[0034] Through the above settings, a large amount of thermal energy can be stored in the energy storage system. This part of heat becomes a flexible energy source. When the thermal power plant is in peak demand or industrial steam needs to be supplied in large quantities, the heat can be released to cooperate with the thermal power plant to generate electricity or provide additional steam.

[0035] The heating COP of this process can be greater than 2.5 (when the high-temperature and high-pressure steam parameters are 0.8MPa and 200℃), which greatly improves the heating efficiency and economy compared with the high-temperature heat pump technology (COP<1.5). This is because there is a large amount of latent heat in the exhaust steam of the turbine. This part of energy originally needs to enter the condenser to take away the heat, thereby turning the low-temperature and low-pressure steam into liquid water and entering the feed water pump of the thermal power plant, but this process will cause a lot of energy waste. If this condensation and cooling process is omitted, the exhaust steam of the turbine is directly passed into the compressor to increase the pressure and temperature, and this large amount of latent heat can be directly utilized. Therefore, the heating COP of this system is relatively high. At the same time, due to the addition of molten salt energy storage as a flexible energy source, the design difficulty of the compressor to adapt to different loads is reduced. In addition, this system is simple to operate, the equipment investment cost is low, and the main steam pipeline of the thermal power plant will not be changed, which has good practical feasibility.

[0036] Embodiment 2:

[0037] The difference between this embodiment 2 and embodiment 1 is that Figure 2 As shown, in Example 2, the compressor group is divided into three groups, and the three compressor groups are connected in parallel. The compressor group includes motor A and compressor A, motor B and compressor B, and motor C and compressor C. Compressor A is connected to heat exchanger A, heat exchanger A is not connected to compressor B, and heat exchanger A is connected to hot salt tank and cold salt tank; compressor B is connected to heat exchanger B, heat exchanger B is not connected to compressor C, and heat exchanger B is connected to hot salt tank and cold salt tank; compressor C is connected to heat exchanger C, and heat exchanger C is connected to hot salt tank and cold salt tank.

[0038] The operating principle of this embodiment is as follows: after the high-temperature and high-pressure steam generated in the boiler in the thermal power plant expands through the steam turbine to do work and drives the generator to generate electricity, the low-pressure saturated steam with a large amount of latent heat enters compressor A, compressor B and compressor C at the same time. After being pressurized and heated by the compressor, the heat is transferred to the molten salt through heat exchanger A, heat exchanger B and heat exchanger C for storage. The steam after heat exchange is incorporated into the industrial steam supply network for industrial steam supply.

[0039] After the heat exchange work of heat exchangers A, B and C, a large amount of thermal energy is stored in the energy storage system. At this time, water is supplied at heat exchanger D, and the hot salt tank and the cold salt tank are used to supply heat. The water is heated to form high-temperature and high-pressure steam for incorporation into the industrial steam supply network, or combined with the high-temperature and high-pressure steam generated in the boiler and continued to be introduced into the turbine for driving power generation.

[0040] Similarly, after the high-temperature and high-pressure steam is pressurized and heated in compressor A, compressor B, or compressor C, it can be directly combined with the high-temperature and high-pressure steam generated in the boiler and then continue to be introduced into the steam turbine to drive the generator to generate electricity. In addition, the number of stages of the compressor group can be adjusted according to actual needs, and the number of the first heat exchangers is also changed accordingly according to the adjustment of the number of compressor groups.

[0041] Embodiment 3:

[0042] The difference between this embodiment 3 and embodiment 1 is that Figure 3 As shown, in embodiment 3, the compressor unit is only provided as one unit. The compressor unit comprises a motor A and a compressor A, the compressor A is connected to a heat exchanger A, and the heat exchanger A is connected to a hot salt tank and a cold salt tank.

[0043] After the heat exchange work of heat exchanger A, a large amount of thermal energy is stored in the energy storage system. At this time, water is fed to the heat exchanger D, and the hot salt tank and the cold salt tank are used for heat supply. The water is heated to form high-temperature and high-pressure steam for incorporation into the industrial steam supply network, or combined with the high-temperature and high-pressure steam generated in the boiler and continued to be introduced into the turbine for driving power generation.

[0044] Similarly, after the high-temperature and high-pressure steam is pressurized and heated in compressor A, it can be directly combined with the high-temperature and high-pressure steam generated in the boiler and then continue to be introduced into the steam turbine to drive the generator to generate electricity.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A system for flexible peak load regulation and steam supply of thermal power, characterized by: Including steam turbine unit, compressor unit and energy storage system; Steam turbine unit: includes a boiler and a steam turbine, the steam turbine is connected to and drives a generator to generate electricity; Compressor unit: The compressor unit is provided in one or more groups, each of which includes an electric motor and a compressor. The low-pressure saturated steam output by the steam turbine enters the compressor and is pressurized and heated to generate high-temperature and high-pressure steam. The compressor is further connected to the steam turbine. The high-temperature and high-pressure steam generated after pressurization and heating is introduced into the steam turbine together with the high-temperature and high-pressure steam generated in the boiler for power generation; Energy storage system: includes high-temperature storage tanks and low-temperature storage tanks, which are used to store the thermal energy in the high-temperature and high-pressure steam generated by the compressor.

2. The system for flexible peak load regulation and steam supply of thermal power according to claim 1, characterized in that: When the compressor unit is configured as a group, the compressor is also connected to a first heat exchanger, and the high-temperature and high-pressure steam after heat exchange is incorporated into the industrial steam supply network. The first heat exchanger is connected to a high-temperature storage tank and a low-temperature storage tank.

3. The system for flexible peak load regulation and steam supply of thermal power according to claim 1, characterized in that: When the compressor group is configured as multiple groups, the multiple compressor groups are connected in series to form a multi-stage compressor group, each compressor group is connected to a first heat exchanger, and the high-temperature and high-pressure steam after heat exchange is incorporated into the industrial steam supply network, and several of the first heat exchangers are connected to high-temperature storage tanks and low-temperature storage tanks at the same time.

4. The system for flexible peak load regulation and steam supply of thermal power according to claim 1, characterized in that: When the compressor groups are arranged in multiple groups, the multiple compressor groups are connected in parallel, each compressor group is respectively connected to a first heat exchanger or all the compressor groups are connected to the same first heat exchanger, and the high-temperature and high-pressure steam after heat exchange is incorporated into the industrial steam supply network, and the first heat exchanger is connected to a high-temperature storage tank and a low-temperature storage tank.

5. A system for flexible peak load regulation and steam supply for thermal power according to any one of claims 2 to 4, characterized in that: The high-temperature storage tank and the low-temperature storage tank are also commonly connected to a second heat exchanger, which generates high-temperature and high-pressure steam after being supplied with water and is incorporated into the industrial steam supply network.

6. A system for flexible peak load regulation and steam supply for thermal power generation according to any one of claims 2 to 4, characterized in that: The high-temperature storage tank and the low-temperature storage tank are also connected to a second heat exchanger. The second heat exchanger generates high-temperature and high-pressure steam after water is fed, and then further pressurized and heated, and then merged into the steam pipe from the boiler to the turbine.

7. The system for flexible peak load regulation and steam supply of thermal power according to claim 1, characterized in that: The steam turbine unit also includes a condenser and a feed water pump. The condenser is connected to the steam turbine. The condenser converts the low-temperature and low-pressure steam output by the steam turbine into liquid water, and inputs the liquid water into the boiler together with the feed water from the feed water pump.

8. The system for flexible peak load regulation and steam supply of thermal power according to claim 1, characterized in that: The high-temperature storage tank and the low-temperature storage tank are molten salt storage tanks.

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