Flexible operation system of thermal power generating units based on molten salt thermal storage

Abstract

A flexible operation system of a thermal power generation unit based on molten salt thermal storage is proposed, which includes a boiler device, a low-temperature tank, a high-temperature tank, a first heat exchanger and a second heat exchanger, in which the inlet end of the heat absorption passage of the first heat exchanger is connected to the outlet end of the low-temperature tank, the outlet end of the heat absorption passage of the first heat exchanger is connected to the inlet end of the high-temperature tank, the inlet end of the heat dissipation passage of the first heat exchanger is connected to the exhaust end of the steam-water separator of the boiler device, and the outlet end of the heat dissipation passage of the first heat exchanger is connected to the inlet end of the water-cooled wall of the boiler device.

Description

[Technical field]

[0001] <Cross-reference of related applications> This application claims priority to Chinese Patent Application No. 202210703817.X, filed in China on June 21, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to the field of thermal power unit technology, and in particular to a flexible operation system for thermal power units based on molten salt thermal storage. [Background technology]

[0003] In recent years, the scale and proportion of renewable energy power generation, such as wind power and solar power, has increased significantly. However, renewable energy is characterized by variability and intermittency, and when connected to the power grid, conventional thermal power generation units need to be able to add auxiliary services such as peak adjustment and peaking. Under the dual background of coal-fired power generation units taking the position of the main power source and at the same time the grid connection of large-scale, unstable renewable energy is urgently required, it is urgent to improve the load adjustment capability of China's thermal power generation units.

[0004] At present, the method of realizing deep peak regulation of thermal power generation units by lowering the minimum output of the boiler unit is often limited by the minimum stable combustion load of the boiler unit. If the stable combustion load of the boiler unit is too low, the equipment such as burner, coal pulverizer, fan and the like cannot operate stably at a load that is too low, so that the thermal power generation unit cannot operate for a long time at a load that is too low. In addition, the method of realizing deep peak regulation of thermal power generation units by lowering the minimum output of the boiler unit is also limited by the minimum inlet smoke temperature of the denitration device. If the stable combustion load of the boiler unit is too low, the flue gas side temperature of the boiler unit will also be low, so that the catalytic activity in the denitration device will be reduced, and the denitration efficiency of the denitration device will be rapidly reduced, and the flue gas requirements of the thermal power generation unit cannot be met. Therefore, the present disclosure proposes a flexible operation system of a thermal power generation unit based on molten salt heat storage to improve the peak regulation ability of the thermal power generation unit. Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure aims to solve at least one of the technical problems in the related art to some extent.

[0006] Therefore, the objective of the present disclosure is to propose a flexible operation system for thermal power generation units based on molten salt thermal storage. [Means for solving the problem]

[0007] In order to achieve the above object, an embodiment of the present disclosure provides a flexible operation system for a thermal power generation unit based on molten salt thermal storage, comprising a boiler device, a low-temperature tank, a high-temperature tank, a first heat exchanger and a second heat exchanger, wherein an inlet end of a heat absorption passage of the first heat exchanger is connected to an outlet end of the low-temperature tank, an outlet end of a heat absorption passage of the first heat exchanger is connected to an inlet end of the high-temperature tank, and an inlet end of a heat dissipation passage of the first heat exchanger is connected to an exhaust end of a steam-water separator of the boiler device. a liquid outlet end of a heat dissipation passage of the first heat exchanger connected to a liquid inlet end of a water-cooled wall of the boiler equipment, a liquid inlet end of a heat dissipation passage of the second heat exchanger connected to a liquid outlet end of the high-temperature tank, a liquid outlet end of a heat dissipation passage of the second heat exchanger connected to a liquid inlet end of the low-temperature tank, a liquid inlet end of a heat absorption passage of the second heat exchanger connected to a liquid outlet end of a feedwater pump of the boiler equipment, and a liquid outlet end of a heat absorption passage of the second heat exchanger connected to a liquid inlet end of a coal economizer of the boiler equipment.

[0008] In some embodiments, the boiler apparatus includes a furnace body, a water-cooled wall provided on an inner wall of the furnace body, the steam-water separator having an outlet end connected to the inlet end of the water-cooled wall and an inlet end connected to the outlet end of the water-cooled wall, the economizer provided within the flue gas end of the furnace body and having an outlet end connected to the inlet end of the water-cooled wall, a high-pressure heater having an outlet end connected to the inlet end of the economizer and an inlet end connected to an exhaust end of a high-pressure cylinder of a steam turbine and an exhaust end of an intermediate-pressure cylinder of the steam turbine, respectively, the feedwater pump having an outlet end connected to the inlet end of the high-pressure heater, and a superheater group provided within the furnace body and having an inlet end connected to the exhaust end of the steam-water separator and an exhaust end connected to the inlet end of the high-pressure cylinder.

[0009] In some embodiments, the flexible operation system of the thermal power unit further includes a recirculation pump provided between the outlet end of the heat absorption passage of the first heat exchanger and the inlet end of the water-cooled wall, the inlet end of which is connected to the outlet end of the heat absorption passage of the first heat exchanger and the outlet end of which is connected to the inlet end of the water-cooled wall.

[0010] In some embodiments, the superheater group includes a horizontal low-temperature superheater having an inlet end connected to an exhaust end of the steam separator, a vertical low-temperature superheater having an inlet end connected to an exhaust end of the horizontal low-temperature superheater, a partition superheater having an inlet end connected to the exhaust end of the vertical low-temperature superheater, a high-temperature superheater having an inlet end connected to the exhaust end of the partition superheater, and a final stage superheater having an inlet end connected to the exhaust end of the high-temperature superheater and an exhaust end connected to an inlet end of a high-pressure cylinder of a steam turbine, and the partition superheater, the high-temperature superheater, the final stage superheater, the vertical low-temperature superheater, the horizontal low-temperature superheater and the economizer are sequentially distributed along a direction from the combustion chamber of the furnace body to the flue gas end of the furnace body.

[0011] In some embodiments, the flexible operation system for the thermal power unit further includes a first valve body provided in a pipeline between the exhaust end of the steam-water separator and the inlet end of a heat dissipation passage of the first heat exchanger, a second valve body provided in a pipeline between the exhaust end of the steam-water separator and the inlet end of the horizontal low-temperature superheater, a third valve body provided in a pipeline between the outlet end of the feedwater pump and the inlet end of the high-pressure heater, and a fourth valve body provided in a pipeline between the outlet end of the feedwater pump and the inlet end of a heat absorption passage of the second heat exchanger.

[0012] In some embodiments, the boiler apparatus further includes a high-temperature reheater provided within the furnace body, located between the final stage superheater and the vertical low-temperature superheater, and having an inlet end connected to the exhaust end of the high-pressure cylinder; and a final stage reheater provided within the furnace body, located between the final stage superheater and the high-temperature reheater, having an inlet end connected to the exhaust end of the high-temperature reheater and an exhaust end connected to the inlet end of the intermediate-pressure cylinder.

[0013] In some embodiments, the flexible operation system of the thermal power unit further includes a third heat exchanger, wherein the heat absorption passage of the third heat exchanger is provided between the outlet end of the heat absorption passage of the first heat exchanger and the inlet end of the high-temperature tank, the inlet end of the heat absorption passage of the third heat exchanger is connected to the outlet end of the heat absorption passage of the first heat exchanger, the outlet end of the heat absorption passage of the third heat exchanger is connected to the inlet end of the high-temperature tank, the heat dissipation passage of the third heat exchanger is provided between the inlet end of the final stage reheater and the exhaust end of the high-temperature reheater, the inlet end of the heat dissipation passage of the third heat exchanger is connected to the exhaust end of the high-temperature reheater, and the inlet end of the final stage reheater is connected to the exhaust end of the heat dissipation passage of the third heat exchanger and the exhaust end of the high-temperature reheater, respectively.

[0014] In some embodiments, the flexible operation system of the thermal power generation unit further includes a fifth valve body provided in a pipe between the inlet end of the heat dissipation passage of the third heat exchanger and the exhaust end of the high-temperature reheater, and a sixth valve body provided in a pipe between the inlet end of the final stage reheater and the exhaust end of the high-temperature reheater.

[0015] In some embodiments, the flexible operation system of the thermal power unit further includes: a low-temperature molten salt pump provided between an inlet end of the heat absorption passage of the first heat exchanger and an outlet end of the low-temperature tank, the inlet end being connected to the outlet end of the low-temperature tank and the outlet end being connected to the inlet end of the heat absorption passage of the first heat exchanger; a seventh valve body provided in a pipeline between the inlet end of the heat absorption passage of the first heat exchanger and the outlet end of the low-temperature molten salt pump; a high-temperature molten salt pump provided between the inlet end of the heat dissipation passage of the second heat exchanger and the outlet end of the high-temperature tank, the inlet end being connected to the outlet end of the high-temperature tank and the outlet end being connected to the inlet end of the heat dissipation passage of the second heat exchanger; and an eighth valve body provided in a pipeline between the inlet end of the heat dissipation passage of the second heat exchanger and the outlet end of the high-temperature molten salt pump.

[0016] In some embodiments, the flexible operation system for the thermal power unit further includes a denitration device having a smoke suction end connected to a smoke exhaust end of the boiler unit. Effect of the Invention

[0017] The technical solutions provided by the present disclosure can include the following beneficial effects: When the demand for electricity is low and the thermal power unit needs to be at its peak, the minimum stable combustion load of the boiler unit can be guaranteed, and the output of the boiler unit can be reduced by the molten salt heat storage, thereby increasing the peak adjustment depth of the thermal power unit and improving the peak adjustment ability of the thermal power unit; the heat stored in the molten salt can be used to increase the inlet water temperature of the economizer, thereby increasing the flue gas end temperature of the boiler unit, and further ensuring the denitration efficiency of the denitration device, so as to meet the flue gas requirements of the thermal power unit; when the demand for electricity is high and the thermal power unit needs to be at its peak, the heat stored in the molten salt can be used to guarantee the inlet water temperature of the economizer, thereby reducing the amount of heating caused by the steam turbine discharged from the steam turbine to the discharge water of the feed water pump, thereby improving the functional capacity of the steam turbine, and realizing the power generation peak of the thermal power unit. This can realize the flexible operation of the thermal power unit and effectively improve the peak adjustment ability of the thermal power unit.

[0018] Additional features and advantages of the present application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the disclosure. [Brief description of the drawings]

[0019] The above and / or additional aspects and advantages of the present disclosure will become more apparent and understandable from the following detailed description of the embodiments taken in conjunction with the drawings. [Figure 1] FIG. 1 is a schematic diagram of a flexible operation system for a thermal power unit based on molten salt thermal storage proposed according to one embodiment of the present disclosure. [Diagram 2] FIG. 1 is a schematic diagram of a flexible operation system for a thermal power unit based on molten salt thermal storage proposed according to one embodiment of the present disclosure. [Diagram 3] FIG. 1 is a schematic diagram of a flexible operation system for a thermal power unit based on molten salt thermal storage proposed according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, the embodiments of the present disclosure will be described in detail, examples of which are shown in the accompanying drawings, in which the same or similar reference numerals throughout indicate the same or similar elements, or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are illustrative and are only intended to illustrate the present disclosure, and are not to be understood as limitations on the present disclosure. Rather, the embodiments of the present disclosure include all changes, modifications, and equivalents contained within the spirit and scope of the appended claims.

[0021] As shown in FIG. 1 , an embodiment of the present disclosure proposes a flexible operation system for a thermal power generation unit based on molten salt thermal storage, the system includes a boiler device 1, a low-temperature tank 2, a high-temperature tank 3, a first heat exchanger 4 and a second heat exchanger 5, in which the inlet end of the heat absorption passage of the first heat exchanger 4 is connected to the outlet end of the low-temperature tank 2, the outlet end of the heat absorption passage of the first heat exchanger 4 is connected to the inlet end of the high-temperature tank 3, and the inlet end of the heat dissipation passage of the first heat exchanger 4 is connected to the steam-water separator of the boiler device 1. 8, the outlet end of the heat dissipation passage of the first heat exchanger 4 is connected to the inlet end of the water-cooled wall 7 of the boiler equipment 1, the inlet end of the heat dissipation passage of the second heat exchanger 5 is connected to the outlet end of the high-temperature tank 3, the outlet end of the heat dissipation passage of the second heat exchanger 5 is connected to the inlet end of the low-temperature tank 2, the inlet end of the heat absorption passage of the second heat exchanger 5 is connected to the outlet end of the feedwater pump 11 of the boiler equipment 1, and the outlet end of the heat absorption passage of the second heat exchanger 5 is connected to the inlet end of the coal economizer 9 of the boiler equipment 1.

[0022] As a result, as shown in FIG. 2, when the demand for electricity use is small, the boiler equipment 1 is at the minimum stable combustion load, and the low-temperature molten salt passes from the low-temperature tank 2 through the heat absorption passage of the first heat exchanger 4 and then enters the high-temperature tank 3, and some of the steam in the steam separator 8 passes through the heat dissipation passage of the first heat exchanger 4 and then enters the water-cooled wall 7, so that the heat in some of the steam in the steam separator 8 is released to the low-temperature molten salt, the low-temperature molten salt turns into high-temperature molten salt, and the high-temperature molten salt is stored in the high-temperature tank 3; Here, as shown in FIG. 1, when the flue gas end temperature of the boiler equipment 1 is low, the low-temperature molten salt is heated by a portion of the steam in the steam separator 8, and the high-temperature molten salt in the high-temperature tank 3 passes through the heat release passage of the second heat exchanger 5 before entering the low-temperature tank 2, and a portion of the discharge water of the feed water pump 11 passes through the heat absorption passage of the second heat exchanger 5 before entering the economizer 9, so that the heat of the high-temperature molten salt is released to a portion of the discharge water of the feed water pump 11, and this portion of the discharge water enters the economizer 9 after being heated.

[0023] As shown in FIG. 3, when the demand for electricity is high, the steam in the steam separator 8 does not enter the heat dissipation passage of the first heat exchanger 4, the high-temperature molten salt in the high-temperature tank 3 passes through the heat dissipation passage of the second heat exchanger 5 before entering the low-temperature tank 2, and all the discharge water of the feedwater pump 11 passes through the heat absorption passage of the second heat exchanger 5 before entering the economizer 9, so that the heat of the high-temperature molten salt is released to all the discharge water of the feedwater pump 11, and all the discharge water of the feedwater pump 11 enters the economizer 9 after being heated.

[0024] In addition, when the demand for electricity is low and the thermal power unit needs to be at its peak, the minimum stable combustion load of the boiler unit 1 can be guaranteed, and the output of the boiler unit 1 can be reduced by the molten salt heat storage, thereby increasing the peak adjustment depth of the large thermal power unit, and improving the peak adjustment ability of the thermal power unit. The heat stored in the molten salt can be used to increase the inlet water temperature of the economizer 9, thereby increasing the flue gas end temperature of the boiler unit 1, and further ensuring the denitration efficiency of the denitration device, and meeting the flue gas requirements of the thermal power unit. When the demand for electricity is high and the thermal power unit needs to be at its peak, the heat stored in the molten salt can be used to guarantee the inlet water temperature of the economizer 9, thereby reducing the amount of heating of the discharged steam of the steam turbine to the discharged water of the feed water pump 11, thereby improving the functional capacity of the steam turbine, and realizing the power generation peak of the thermal power unit. This realizes the flexible operation of the thermal power unit, and effectively improves the peak adjustment ability of the thermal power unit.

[0025] Here, some of the steam in the steam separator 8 enters the water-cooled wall 7 after heat dissipation, thereby increasing the working fluid flow rate in the water-cooled wall 7, reducing the steam amount of the boiler unit 1, reducing the output of the boiler unit 1, and further increasing the peak adjustment depth of the large thermal power generation unit.

[0026] Both the first heat exchanger 4 and the second heat exchanger include a heat absorption passage and a heat dissipation passage for heat exchange, and direct heat exchange is possible between the heat absorption passage and the heat dissipation passage, and indirect heat exchange is possible between the heat absorption passage and the heat dissipation passage via a heat conductive medium.

[0027] As shown in FIG. 1, in some embodiments, the boiler apparatus 1 includes a furnace body 6, a water-cooled wall 7, a steam-water separator 8, a coal economizer 9, a high-pressure heater 10, a feed water pump 11, and a superheater group, the water-cooled wall 7 is provided on the inner wall of the furnace body 6, the outlet end of the steam-water separator 8 is connected to the inlet end of the water-cooled wall 7, the inlet end of the steam-water separator 8 is connected to the outlet end of the water-cooled wall 7, the coal economizer 9 is provided in the flue gas end of the furnace body 6, and the outlet end of the coal economizer 9 is connected to the inlet end of the water-cooled wall 7. The outlet end of the high-pressure heater 10 is connected to the inlet end of the coal economizer 9, the inlet end of the high-pressure heater 10 is connected to the exhaust end of the high-pressure cylinder of the steam turbine and the exhaust end of the intermediate-pressure cylinder of the steam turbine, the outlet end of the feed water pump 11 is connected to the inlet end of the high-pressure heater 10, the superheater group is provided in the furnace body 6, the inlet ends of the superheater group are connected to the exhaust end of the steam-water separator 8, and the exhaust ends of the superheater group are connected to the inlet end of the high-pressure cylinder.

[0028] The water-cooled wall 7 absorbs the radiant heat emitted from the flame and high-temperature smoke in the furnace body 6, and the water or steam in the water-cooled wall 7 enters the steam-water separator 8 to separate the steam and water. The water in the steam-water separator 8 returns to the water-cooled wall and continues to be used. When the demand for electricity is low, as shown in FIG. 2, part of the steam in the steam-water separator 8 enters the heat dissipation passage of the first heat exchanger 4 to dissipate heat and reduce the output of the boiler unit 1. When the demand for electricity is high, as shown in FIG. 3, all of the steam in the steam-water separator 8 enters the superheater group to increase the output of the boiler unit 1.

[0029] When the demand for electricity is small and the flue gas end temperature of the boiler unit 1 is high, as shown in Fig. 2, the external water or deoxygenated water is pressurized and transported by the feed water pump 11, and passes through the high pressure heater 10 and the economizer 9 in sequence before entering the water wall 7, thereby ensuring the use of water in the boiler unit 1. When the demand for electricity is small and the flue gas end temperature of the boiler unit 1 is low, as shown in Fig. 1, some of the external water or deoxygenated water is pressurized and transported by the feed water pump 11, and passes through the high pressure heater 10 and the economizer 9 in sequence before entering the water wall 7, and the remaining external water or deoxygenated water is heated and transported by the feed water pump 11, and passes through the heat absorption passage of the second heat exchanger 5 and the economizer 9 before entering the water wall 7, thereby increasing the flue gas end temperature of the boiler unit 1. When the demand for electricity is high, as shown in FIG. 3, external water or deoxygenated water is heated and transported by the feed water pump 11, passes through the heat absorption passage of the second heat exchanger 5 and the economizer 9, and then enters the water wall 7, thereby increasing the output of the boiler unit 1.

[0030] The steam turbine includes a high-pressure cylinder, a medium-pressure cylinder, and a low-pressure cylinder, and the main steam generated in the boiler unit 1 passes through the high-pressure cylinder, the medium-pressure cylinder, and the low-pressure cylinder in order to perform work before entering the condenser, which cools and condenses the steam after work into condensate, which is heated by the low-pressure heater before entering the deaerator, and the water from the deaerator becomes deoxygenated water. Here, the low-pressure heater heats the condensate with the discharge steam from the medium-pressure cylinder and the low-pressure cylinder, and the heated steam enters the outlet end of the condenser, and the high-pressure heater 10 heats the deoxygenated water with the discharge steam from the high-pressure cylinder and the medium-pressure cylinder, and the heated steam enters the inlet end of the deaerator.

[0031] As shown in FIG. 1 , in some embodiments, the flexible operation system of the thermal power unit further includes a recirculation pump 12 arranged between the outlet end of the heat absorption passage of the first heat exchanger 4 and the inlet end of the water cooling wall 7, with the inlet end connected to the outlet end of the heat absorption passage of the first heat exchanger 4 and the outlet end connected to the inlet end of the water cooling wall 7.

[0032] The recirculation pump 12 pressurizes the discharge water from the heat absorption passage of the first heat exchanger 4 and transports it to the water-cooled wall 7, thereby ensuring stable heat dissipation from a portion of the steam in the steam separator 8.

[0033] As shown in FIG. 1 , in some embodiments, the superheater group includes a horizontal low-temperature superheater 13, a vertical low-temperature superheater 14, a partition superheater 15, a high-temperature superheater 16 and a final stage superheater 17, and the inlet end of the horizontal low-temperature superheater 13 is connected to the exhaust end of the steam separator 8, the inlet end of the vertical low-temperature superheater 14 is connected to the exhaust end of the horizontal low-temperature superheater 13, the inlet end of the partition superheater 15 is connected to the exhaust end of the vertical low-temperature superheater 14, the inlet end of the high-temperature superheater 16 is connected to the exhaust end of the partition superheater 15, the inlet end of the final stage superheater 17 is connected to the exhaust end of the high-temperature superheater 16, and the exhaust end of the final stage superheater 17 is connected to the inlet end of the high-pressure cylinder of the steam turbine; Here, the partition plate superheater 15, the high-temperature superheater 16, the final stage superheater 17, the vertical low-temperature superheater 14, the horizontal low-temperature superheater 13 and the economizer 9 are sequentially distributed along the direction from the combustion chamber of the furnace body 6 to the flue gas end of the furnace body 6.

[0034] The steam in the steam separator 8 passes through the horizontal low-temperature superheater 13, the vertical low-temperature superheater 14, the partition plate superheater 15, the high-temperature superheater 16 and the final stage superheater 17 in sequence, before being heated to main steam sufficient to fill the high-pressure cylinder of the steam turbine. The main steam then enters the high-pressure cylinder of the steam turbine to perform work, thereby generating electricity in the thermal power generation unit.

[0035] As shown in FIG. 1 , in some embodiments, the flexible operation system of the thermal power unit further includes a first valve body 18, a second valve body 19, a third valve body 20 and a fourth valve body 21, where the first valve body 18 is provided in a pipeline between the exhaust end of the steam-water separator 8 and the inlet end of the heat dissipation passage of the first heat exchanger 4, the second valve body 19 is provided in a pipeline between the exhaust end of the steam-water separator 8 and the inlet end of the horizontal low-temperature superheater 13, the third valve body 20 is provided in a pipeline between the outlet end of the feedwater pump 11 and the inlet end of the high-pressure heater 10, and the fourth valve body 21 is provided in a pipeline between the outlet end of the feedwater pump 11 and the inlet end of the heat absorption passage of the second heat exchanger 5.

[0036] In addition, when the demand for electricity is low, the openings of the first valve body 18 and the second valve body 19 are adjusted so that part of the steam in the steam separator 8 enters the heat dissipation passage of the first heat exchanger 4 to dissipate heat, and the remaining steam enters the horizontal low-temperature superheater 13, the vertical low-temperature superheater 14, the partition plate superheater 15, the high-temperature superheater 16, and the final stage superheater 17 in sequence to absorb heat, as shown in Figure 2. In addition, when the exhaust end temperature of the boiler unit 1 is high, the third valve body 20 is opened and the fourth valve body 21 is closed so that all the discharge water of the feed water pump 11 enters the high-pressure heater 10 to absorb heat, as shown in Figure 2. When the exhaust end temperature of the boiler unit 1 is low, the openings of the third valve body 20 and the fourth valve body 21 are adjusted so that part of the discharge water of the feed water pump 11 enters the high-pressure heater 10 to absorb heat, and the remaining discharge water enters the heat absorption passage of the second heat exchanger 5 to absorb heat, as shown in Figure 1.

[0037] When the demand for electricity is high, as shown in FIG. 3, the first valve body 18 and the third valve body 20 are closed and the second valve body 19 and the fourth valve body 21 are opened so that all the steam in the steam-water separator 8 sequentially enters the horizontal low-temperature superheater 13, the vertical low-temperature superheater 14, the partition plate superheater 15, the high-temperature superheater 16 and the final stage superheater 17 to absorb heat, and all the discharge water from the feed water pump 11 enters the heat absorption passage of the second heat exchanger 5 to absorb heat.

[0038] As a result, the installation of the first valve body 18, the second valve body 19, the third valve body 20 and the fourth valve body 21 facilitates the distribution of steam in the steam separator 8 between the heat dissipation passage of the first heat exchanger 4 and the horizontal low-temperature superheater 13, and the distribution of the discharge water of the feedwater pump 11 between the high-pressure heater 10 and the heat absorption passage of the second heat exchanger 5, making the overall use more convenient.

[0039] As shown in FIG. 1, in some embodiments, the boiler apparatus 1 further includes a high-temperature reheater 22 and a final stage reheater 23, where the high-temperature reheater 22 is installed in the furnace body 6, the high-temperature reheater 22 is located between the final stage superheater 17 and the vertical low-temperature superheater 14, the inlet end of the high-temperature reheater 22 is connected to the exhaust end of the high-pressure cylinder, the final stage reheater 23 is installed in the furnace body 6, the final stage reheater 23 is located between the final stage superheater 17 and the high-temperature reheater 22, the inlet end of the final stage reheater 23 is connected to the exhaust end of the high-temperature reheater 22, and the exhaust end of the final stage reheater 23 is connected to the inlet end of the intermediate pressure cylinder.

[0040] In addition, the steam discharged from the high-pressure cylinder of the steam turbine passes through the high-temperature reheater 22 and the final stage reheater 23 in sequence, and is then heated to a level that satisfies the demand of the medium-pressure cylinder of the steam turbine. The reheated steam then enters the medium-pressure cylinder of the steam turbine to perform work, thereby generating electricity in the thermal power generation unit.

[0041] As shown in FIG. 1, in some embodiments, the flexible operation system of the thermal power unit further includes a third heat exchanger 24, the heat absorption passage of the third heat exchanger 24 is arranged between the outlet end of the heat absorption passage of the first heat exchanger 4 and the inlet end of the high-temperature tank 3, the inlet end of the heat absorption passage of the third heat exchanger 24 is connected to the outlet end of the heat absorption passage of the first heat exchanger 4, the outlet end of the heat absorption passage of the third heat exchanger 24 is connected to the inlet end of the high-temperature tank 3, the heat dissipation passage of the third heat exchanger 24 is arranged between the inlet end of the final stage reheater 23 and the exhaust end of the high-temperature reheater 22, the inlet end of the heat dissipation passage of the third heat exchanger 24 is connected to the exhaust end of the high-temperature reheater 22, and the inlet end of the final stage reheater 23 is connected to the exhaust end of the heat dissipation passage of the third heat exchanger 24 and the exhaust end of the high-temperature reheater 22 respectively.

[0042] As a result, when the demand for electricity is small, as shown in Figure 2, the boiler equipment 1 is at the minimum stable combustion load, and the low-temperature molten salt passes from the low-temperature tank 2 sequentially through the heat absorption passage of the first heat exchanger 4 and the heat absorption passage of the third heat exchanger 24 before entering the high-temperature tank 3, a part of the discharged steam from the high-temperature reheater 22 passes through the heat dissipation passage of the third heat exchanger 24 before entering the final stage reheater 23, and the remaining discharged steam directly enters the final stage reheater 23, so that the heat of a part of the discharged steam from the high-temperature reheater 22 is discharged to the high-temperature molten salt in the heat absorption passage of the third heat exchanger 24, and the high-temperature molten salt is further heated and then stored in the high-temperature tank 3.

[0043] When the demand for electricity usage is high, as shown in FIG. 3, all the discharge steam of the high temperature reheater 22 directly enters the final stage reheater 23, thereby increasing the output of the boiler unit 1.

[0044] In addition, when the demand for electricity is low and deep peak adjustment of the thermal power generation unit is required, the minimum stable combustion load of the boiler device 1 is guaranteed and the output of the boiler device 1 is further reduced by molten salt thermal storage, the peak adjustment depth of the large thermal power generation unit is increased again, and the peak adjustment capability of the thermal power generation unit is further improved.

[0045] The third heat exchanger 24 includes a heat absorption passage and a heat dissipation passage for heat exchange, and direct heat exchange is possible between the heat absorption passage and the heat dissipation passage, and indirect heat exchange is possible between the heat absorption passage and the heat dissipation passage via a heat conductive medium.

[0046] As shown in FIG. 1 , in some embodiments, the flexible operation system of the thermal power unit further includes a fifth valve body 25 and a sixth valve body 26, where the fifth valve body 25 is installed in the pipe between the inlet end of the heat dissipation passage of the third heat exchanger 24 and the exhaust end of the high-temperature reheater 22, and the sixth valve body 26 is installed in the pipe between the inlet end of the final stage reheater 23 and the exhaust end of the high-temperature reheater 22.

[0047] In addition, when the demand for electricity is low, as shown in Figure 2, the opening degrees of the fifth valve body 25 and the sixth valve body 26 are adjusted so that a portion of the discharged steam from the high-temperature reheater 22 enters the third heat exchanger 24 to release heat, and the remaining discharged steam enters directly into the final stage reheater 23 to absorb heat.

[0048] When the demand for electricity is high, as shown in FIG. 3, the fifth valve body 25 is closed and the sixth valve body 26 is opened so that all the discharged steam from the high temperature reheater 22 directly enters the final stage reheater 23 to absorb heat.

[0049] As a result, the installation of the fifth valve body 25 and the sixth valve body 26 facilitates the distribution of steam within the high-temperature reheater 22 between the heat dissipation passage of the third heat exchanger 24 and the final stage reheater 23, making the overall use more convenient.

[0050] As shown in FIG. 1 , in some embodiments, the flexible operation system of the thermal power unit further includes a low-temperature molten salt pump 27, a seventh valve body 28, a high-temperature molten salt pump 29 and an eighth valve body 30, where the low-temperature molten salt pump 27 is disposed between the inlet end of the heat absorption passage of the first heat exchanger 4 and the outlet end of the low-temperature tank 2, the inlet end of the low-temperature molten salt pump 27 is connected to the outlet end of the low-temperature tank 2, and the outlet end of the low-temperature molten salt pump 27 is connected to the inlet end of the heat absorption passage of the first heat exchanger 4; the seventh valve body 28 is disposed between the inlet end of the heat absorption passage of the first heat exchanger 4 and the outlet end of the low-temperature tank 2; The eighth valve body 30 is provided in the pipeline between the inlet end of the heat absorption passage of the first heat exchanger 4 and the outlet end of the low-temperature molten salt pump 27, the high-temperature molten salt pump 29 is provided between the inlet end of the heat dissipation passage of the second heat exchanger 5 and the outlet end of the high-temperature tank 3, the inlet end of the high-temperature molten salt pump 29 is connected to the outlet end of the high-temperature tank 3 and the outlet end of the high-temperature molten salt pump 29 is connected to the inlet end of the heat dissipation passage of the second heat exchanger 5, and the eighth valve body 30 is provided in the pipeline between the inlet end of the heat dissipation passage of the second heat exchanger 5 and the outlet end of the high-temperature molten salt pump 29.

[0051] In addition, the low-temperature molten salt in the low-temperature tank 2 is pressurized and transported by the low-temperature molten salt pump 27, and then passes through the heat absorption passage of the first heat exchanger 4 and the heat absorption passage of the third heat exchanger 24 before entering the high-temperature tank 3, thereby ensuring stable heat absorption by the low-temperature molten salt, and the high-temperature molten salt in the high-temperature tank 3 is pressurized and transported by the high-temperature molten salt pump 29, and then passes through the heat dissipation passage of the third heat exchanger 24 before entering the low-temperature tank 2, thereby ensuring stable heat dissipation by the high-temperature molten salt.

[0052] The seventh valve body 28 and the eighth valve body 30 are provided to facilitate the opening and closing control of the passage between the low temperature tank 2 and the high temperature tank 3, and make the whole system more convenient to use.

[0053] When the demand for electricity is small, as shown in FIG. 2, the low-temperature molten salt pump 27 and the seventh valve body 28 are opened, so that the low-temperature molten salt in the low-temperature tank 2 flows into the high-temperature tank 3; when the flue gas end temperature of the boiler equipment 1 is low, the high-temperature molten salt pump 29 and the eighth valve are opened, so that the high-temperature molten salt in the high-temperature tank 3 flows into the low-temperature tank 2; when the flue gas end temperature of the boiler equipment 1 is high, the high-temperature molten salt pump 29 and the eighth valve are closed.

[0054] When the demand for electricity is high, as shown in FIG. 3, the high-temperature molten salt pump 29 and the eighth valve are opened to allow the high-temperature molten salt in the high-temperature tank 3 to enter the low-temperature tank 2, and at the same time, the low-temperature molten salt pump 27 and the seventh valve body 28 are closed.

[0055] In addition, the first valve body 18, the second valve body 19, the third valve body 20, the fourth valve body 21, the fifth valve body 25, the sixth valve body 26, the seventh valve body 28 and the eighth valve body 30 may all be manual opening / closing valves or electromagnetic opening / closing valves.

[0056] In some embodiments, the flexible operation system of the thermal power unit further includes a denitration device, the smoke suction end of which is connected to the smoke exhaust end of the boiler unit 1 .

[0057] In addition, the smoke discharged from the boiler unit 1 is denitrified by the denitrification device before being discharged to the outside, which meets the smoke exhaust requirements of the thermal power generation unit. At the same time, by utilizing the energy stored in the molten salt, it is ensured that the temperature of the exhaust smoke at the end of the boiler unit 1 is always higher than the minimum inlet smoke temperature of the denitrification device, thereby ensuring high-efficiency denitrification by the denitrification device.

[0058] It should be noted that in the description of this disclosure, the terms "first," "second," etc. are used for descriptive purposes only and are not to be understood to denote or imply relative importance. In the description of this disclosure, "plurality" means two or more, unless otherwise specified.

[0059] Any process or method description depicted in a flowchart or otherwise herein may be understood to represent a module, fragment, or portion of code of one or more executable instructions comprising steps for implementing particular logical functions or processes, and those skilled in the art of the embodiments of the present disclosure will appreciate that the scope of the preferred embodiments of the present disclosure includes additional implementations that may not be in the order shown or discussed, including performing functions essentially simultaneously or in reverse order according to the associated functionality.

[0060] In the description herein, a description that refers to terms such as "one embodiment," "some embodiments," "examples," "particular examples," or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the disclosure. In the description herein, generalized versions of the terms do not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0061] Although the embodiments of the present disclosure have been shown and described above, the above embodiments are illustrative and should not be construed as limitations on the present disclosure. Those skilled in the art may change, modify, substitute, and alter the above embodiments within the scope of the present disclosure. [Explanation of symbols]

[0062] 1. Boiler equipment 2. Low temperature tank 3. High temperature tank 4. First heat exchanger 5. Second heat exchanger 6, Furnace body 7, water cooling wall 8, Steam water separator 9, Economizer 10. High pressure heater 11. Water supply pump 12. Recirculation pump 13, horizontal low temperature superheater 14, vertical low temperature superheater 15. Partition plate superheater 16, high temperature superheater 17, Final stage superheater 18. First valve body 19. Second valve body 20. Third valve body 21. Fourth valve body 22, high temperature reheater 23, final stage reheater 24. The third heat exchanger 25. Fifth valve body 26. 6th valve body 27. Low temperature molten salt pump 28. 7th valve body 29. High temperature molten salt pump 30. 8th valve body

Claims

1. A flexible operation system for a thermal power generation unit based on molten salt thermal storage, comprising: The present invention includes a boiler apparatus, a low-temperature molten salt tank, a high-temperature molten salt tank, a first heat exchanger, and a second heat exchanger, an inlet end of a heat absorption passage of the first heat exchanger is connected to an outlet end of the low temperature molten salt tank, an outlet end of a heat absorption passage of the first heat exchanger is connected to an inlet end of the high temperature molten salt tank, an inlet end of a heat dissipation passage of the first heat exchanger is connected to an exhaust end of a steam-water separator of the boiler apparatus, and an outlet end of a heat dissipation passage of the first heat exchanger is connected to an inlet end of a water-cooled wall of the boiler apparatus; an inlet end of a heat dissipation passage of the second heat exchanger is connected to an outlet end of the high temperature molten salt tank, an outlet end of a heat dissipation passage of the second heat exchanger is connected to an inlet end of the low temperature molten salt tank, an inlet end of a heat absorption passage of the second heat exchanger is connected to an outlet end of a feed water pump of the boiler apparatus, and an outlet end of a heat absorption passage of the second heat exchanger is connected to an inlet end of a coal economizer of the boiler apparatus; The molten salt circulates through a passage including the low-temperature molten salt tank, the first heat exchanger, the high-temperature molten salt tank, and the second heat exchanger; The boiler apparatus includes a furnace body, a water-cooled wall, the steam-water separator, the economizer, a high-pressure heater, the feed water pump, and a superheater group, The water-cooled wall is provided on the inner wall of the furnace body, The outlet end of the steam-water separator is connected to the inlet end of the water-cooled wall, and the inlet end of the steam-water separator is connected to the outlet end of the water-cooled wall, The economizer is provided in the flue gas end of the furnace body, and the liquid outlet end of the economizer is connected to the liquid inlet end of the water-cooled wall; a liquid outlet end of the high-pressure heater is connected to a liquid inlet end of the economizer, and an air inlet end of the high-pressure heater is connected to an exhaust end of a high-pressure cylinder of a steam turbine and an exhaust end of an intermediate-pressure cylinder of the steam turbine, The outlet end of the feedwater pump is connected to the inlet end of the high-pressure heater; the superheater group is provided in the furnace body, an inlet port of the superheater group is connected to an exhaust port of the steam-water separator, and an exhaust port of the superheater group is connected to an inlet port of the high-pressure cylinder; A flexible operation system for a thermal power generation unit based on molten salt thermal storage, characterized in that

2. The flexible operation system of a thermal power generation unit based on molten salt thermal storage comprises: a recirculation pump provided between the outlet end of the heat absorption passage of the first heat exchanger and the inlet end of the water-cooled wall, the inlet end being connected to the outlet end of the heat absorption passage of the first heat exchanger and the outlet end being connected to the inlet end of the water-cooled wall; The flexible operation system of a thermal power generation unit based on molten salt thermal storage as claimed in claim 1.

3. The superheater group includes: a horizontal low-temperature superheater having an inlet end connected to an exhaust end of the steam separator; a vertical low-temperature superheater having an inlet end connected to the exhaust end of the horizontal low-temperature superheater; a partition plate superheater having an inlet end connected to an exhaust end of the vertical low-temperature superheater; a high-temperature superheater having an inlet end connected to an exhaust end of the partition plate superheater; a final stage superheater having an inlet end connected to an exhaust end of the high-temperature superheater and an exhaust end connected to an inlet end of a high-pressure cylinder of a steam turbine; The partition plate superheater, the high-temperature superheater, the final stage superheater, the vertical low-temperature superheater, the horizontal low-temperature superheater and the economizer are sequentially distributed along a direction from the combustion chamber of the furnace body to the flue gas end of the furnace body; The flexible operation system of a thermal power generation unit based on molten salt thermal storage as claimed in claim 1.

4. The flexible operation system of a thermal power generation unit based on molten salt thermal storage comprises: a first valve body provided in a pipe between an exhaust end of the steam separator and an inlet end of a heat radiation passage of the first heat exchanger; a second valve body provided in a pipeline between an exhaust end of the steam separator and an inlet end of the horizontal low-temperature superheater; a third valve body provided in a pipeline between the outlet end of the feedwater pump and the inlet end of the high-pressure heater; a fourth valve body provided in a pipeline between the outlet end of the water supply pump and the inlet end of the heat absorption passage of the second heat exchanger, The flexible operation system of a thermal power generation unit based on molten salt thermal storage as claimed in claim 3.

5. The boiler device includes: a high-temperature reheater provided in the furnace body, located between the final stage superheater and the vertical low-temperature superheater, the high-temperature reheater having an inlet connected to an exhaust end of the high-pressure cylinder; a final stage reheater provided in the furnace body, located between the final stage superheater and the high-temperature reheater, the inlet end being connected to the exhaust end of the high-temperature reheater and the exhaust end being connected to the inlet end of the intermediate pressure cylinder; The flexible operation system of a thermal power generation unit based on molten salt thermal storage as claimed in claim 3.

6. The flexible operation system for a thermal power unit based on molten salt thermal storage further includes a third heat exchanger; the heat absorption passage of the third heat exchanger is provided between the outlet end of the heat absorption passage of the first heat exchanger and the inlet end of the high-temperature molten salt tank, the inlet end of the heat absorption passage of the third heat exchanger is connected to the outlet end of the heat absorption passage of the first heat exchanger, and the outlet end of the heat absorption passage of the third heat exchanger is connected to the inlet end of the high-temperature molten salt tank; the heat dissipation passage of the third heat exchanger is provided between the inlet end of the final stage reheater and the exhaust end of the high temperature reheater, the inlet end of the heat dissipation passage of the third heat exchanger is connected to the exhaust end of the high temperature reheater, and the inlet end of the final stage reheater is connected to the exhaust end of the heat dissipation passage of the third heat exchanger and the exhaust end of the high temperature reheater, respectively. The flexible operation system of a thermal power generation unit based on molten salt thermal storage as claimed in claim 5.

7. The flexible operation system of a thermal power generation unit based on molten salt thermal storage comprises: a fifth valve body provided in a pipe between an inlet end of a heat radiation passage of the third heat exchanger and an exhaust end of the high-temperature reheater; and a sixth valve body provided in a pipeline between the inlet end of the final stage reheater and the exhaust end of the high temperature reheater. The flexible operation system of a thermal power generation unit based on molten salt thermal storage as claimed in claim 6.

8. The flexible operation system of a thermal power generation unit based on molten salt thermal storage comprises: a low-temperature molten salt pump provided between an inlet end of the heat absorption passage of the first heat exchanger and an outlet end of the low-temperature molten salt tank, the inlet end being connected to the outlet end of the low-temperature molten salt tank and the outlet end being connected to the inlet end of the heat absorption passage of the first heat exchanger; a seventh valve body provided in a pipeline between an inlet end of the heat absorption passage of the first heat exchanger and an outlet end of the low-temperature molten salt pump; a high-temperature molten salt pump provided between an inlet end of the heat dissipation passage of the second heat exchanger and an outlet end of the high-temperature molten salt tank, the inlet end being connected to the outlet end of the high-temperature molten salt tank and the outlet end being connected to the inlet end of the heat dissipation passage of the second heat exchanger; and an eighth valve body provided in a pipeline between an inlet end of the heat dissipation passage of the second heat exchanger and an outlet end of the high-temperature molten salt pump. A system for flexible operation of a thermal power generation unit based on molten salt thermal storage according to any one of claims 1 to 7.

9. The flexible operation system of a thermal power generation unit based on molten salt thermal storage comprises: Further comprising a denitration device having a smoke suction end connected to the smoke exhaust end of the boiler apparatus; A system for flexible operation of a thermal power generation unit based on molten salt thermal storage according to any one of claims 1 to 7.

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