A load-adjustable back pressure unit

Abstract

The present disclosure proposes a load-adjustable back pressure unit, comprising: a steam turbine; an electric heater, the electric energy input end of the electric heater is connected to the electric energy output end of the steam turbine; a low-temperature tank, the molten salt output end of the low-temperature tank is connected to the molten salt input end of the electric heater; a high-temperature tank, the molten salt input end of the high-temperature tank is connected to the molten salt output end of the electric heater; a heat exchanger, the hot side passage input end of the heat exchanger is connected to the molten salt output end of the high-temperature tank, the hot side passage output end of the heat exchanger is connected to the molten salt input end of the low-temperature tank, the cold side passage input end of the heat exchanger is connected to the feed water input end of the steam turbine, and the cold side passage output end of the heat exchanger is connected to the steam input end of the steam-consuming equipment and the steam input end of the steam turbine. In a load-adjustable back pressure unit disclosed in the present disclosure, while ensuring the accuracy of electric load regulation, the rate and amplitude of electric load response are maximized to meet usage requirements.

Description

Technical Field

[0001] The present disclosure relates to the technical field of back pressure units, and in particular to a load-adjustable back pressure unit. Background Art

[0002] Backpressure units adjust their power generation load based on thermal load. This means their power generation varies with the amount of steam supplied, resulting in better economic efficiency. With the development of renewable energy sources like wind and photovoltaic power, and the large-scale integration of renewable energy into the grid, the volatility and intermittency of renewable energy sources have necessitated the rapid and frequent changes in power load required to maintain grid stability.

[0003] At present, there are many methods for quickly adjusting the electric load of units. For example, the method of using batteries, flywheels, supercapacitors and other energy storage means to adjust the load has problems such as high transformation cost, short life, and small capacity. It cannot be used on a large scale in power grids with scarce frequency regulation resources. For example, the method of using compressed air energy storage, pumped storage and other energy storage means to adjust the load, although it has the advantages of large capacity, long duration and long service life, its response rate is low and it cannot achieve accurate and rapid adjustment of the electric load. Summary of the Invention

[0004] The present disclosure aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, the purpose of the present disclosure is to provide a load-adjustable back pressure unit.

[0006] To achieve the above-mentioned objectives, the present disclosure provides a load-adjustable back pressure unit, comprising: a steam turbine, wherein the power output end of the steam turbine is connected to the power input end of the power grid, and the steam output end of the steam turbine is connected to the steam input end of the steam-consuming equipment; an electric heater, wherein the power input end of the electric heater is connected to the power output end of the steam turbine; a low-temperature tank, wherein the molten salt output end of the low-temperature tank is connected to the molten salt input end of the electric heater; a high-temperature tank, wherein the molten salt input end of the high-temperature tank is connected to the molten salt output end of the electric heater; a heat exchanger, wherein the hot side passage input end of the heat exchanger is connected to the molten salt output end of the high-temperature tank, the hot side passage output end of the heat exchanger is connected to the molten salt input end of the low-temperature tank, the cold side passage input end of the heat exchanger is connected to the feed water input end of the steam turbine, and the cold side passage output end of the heat exchanger is connected to the steam input end of the steam-consuming equipment and the steam input end of the steam turbine.

[0007] Optionally, the steam turbine includes: a boiler, wherein the feed water input end of the boiler is connected to the cold side passage input end of the heat exchanger; a high-pressure cylinder, wherein the steam input end of the high-pressure cylinder is connected to the main steam output end of the boiler, and the steam output end of the high-pressure cylinder is connected to the reheat steam input end of the boiler; an intermediate-pressure cylinder, wherein the steam input end of the intermediate-pressure cylinder is connected to the reheat steam output end of the boiler and the cold side passage output end of the heat exchanger, and the steam output end of the intermediate-pressure cylinder is connected to the steam input end of the steam-consuming equipment; a low-pressure cylinder, wherein the steam input end of the low-pressure cylinder is connected to the steam output end of the intermediate-pressure cylinder; a generator, wherein the power input end of the generator is connected to the power output ends of the high-pressure cylinder, the intermediate-pressure cylinder and the low-pressure cylinder, and the electric energy output end of the generator is connected to the electric energy input end of the power grid and the electric energy input end of the electric heater.

[0008] Optionally, the back pressure unit also includes: a first regulating valve, which is arranged on the pipeline between the steam input end of the intermediate pressure cylinder and the output end of the cold side passage of the heat exchanger; a first one-way valve, which is arranged on the pipeline between the steam input end of the intermediate pressure cylinder and the output end of the cold side passage of the heat exchanger, and the first one-way valve is conductive in the direction from the output end of the cold side passage of the heat exchanger to the steam input end of the intermediate pressure cylinder; a second regulating valve, which is arranged on the pipeline between the steam output end of the intermediate pressure cylinder and the steam input end of the steam-consuming equipment; a second one-way valve, which is arranged on the pipeline between the steam output end of the intermediate pressure cylinder and the steam input end of the steam-consuming equipment, and the second one-way valve is conductive in the direction from the steam output end of the intermediate pressure cylinder to the steam input end of the steam-consuming equipment; wherein, the switching states of the first regulating valve and the second regulating valve are opposite.

[0009] Optionally, the steam turbine further includes: a deaerator, wherein the feed water input end of the deaerator is connected to the steam output end of the low-pressure cylinder, and the feed water output end of the deaerator is connected to the feed water input end of the boiler and the cold side passage input end of the heat exchanger.

[0010] Optionally, the back pressure unit also includes: a first pump body, which is arranged on the pipeline between the water supply output end of the deaerator and the cold side passage input end of the heat exchanger, the water supply input end of the first pump body is connected to the water supply output end of the deaerator, and the water supply output end of the first pump body is connected to the cold side passage input end of the heat exchanger; a third regulating valve, which is arranged on the pipeline between the water supply output end of the deaerator and the water supply input end of the first pump body.

[0011] Optionally, the steam turbine also includes: a second pump body, the water feed input end of the second pump body is connected to the water feed output end of the deaerator; a high-pressure heater, the hot side passage input end of the high-pressure heater is connected to the steam output end of the high-pressure cylinder and the steam output end of the medium-pressure cylinder, the hot side passage output end of the high-pressure heater is connected to the water feed input end of the second pump body, the cold side passage input end of the high-pressure heater is connected to the water feed output end of the second pump body, and the cold side passage output end of the high-pressure heater is connected to the water feed input end of the boiler.

[0012] Optionally, the back pressure unit also includes: a transformer, the power input end of the transformer is connected to the power output end of the generator; a power regulator, the power input end of the power regulator is connected to the power output end of the transformer, and the power output end of the power regulator is connected to the power input end of the electric heater.

[0013] Optionally, the electric heater includes: a heating tank, the molten salt input end of the heating tank is connected to the molten salt output end of the low-temperature tank, and the molten salt output end of the heating tank is connected to the molten salt input end of the high-temperature tank; a heating tube, the heating tube is arranged in the heating tank, and the power input end of the heating tube is connected to the power output end of the power regulator.

[0014] Optionally, the back pressure unit also includes: a third pump body, which is arranged on the pipeline between the molten salt output end of the low-temperature tank and the molten salt input end of the electric heater, the molten salt input end of the third pump body is connected to the molten salt output end of the low-temperature tank, and the molten salt output end of the third pump body is connected to the molten salt input end of the electric heater; a fourth pump body, which is arranged on the pipeline between the hot side passage input end of the heat exchanger and the molten salt output end of the high-temperature tank, the molten salt input end of the fourth pump body is connected to the molten salt output end of the high-temperature tank, and the molten salt output end of the fourth pump body is connected to the hot side passage input end of the heat exchanger.

[0015] Optionally, the back pressure unit also includes: a fourth regulating valve, which is arranged on the pipeline between the molten salt output end of the third pump body and the molten salt input end of the electric heater; and a fifth regulating valve, which is arranged on the pipeline between the molten salt output end of the fourth pump body and the hot side passage input end of the heat exchanger.

[0016] The technical solution provided by the present disclosure may have the following beneficial effects:

[0017] Using an electric heater to heat molten salt as a controllable load for the steam turbine can not only improve the peak-shaving capability of the steam turbine, but also reduce the power of the electric heater so that the electrical load from the steam turbine to the power grid can be quickly increased. At the same time, the heat stored in the molten salt can be used to generate steam, thereby increasing the power generation of the steam turbine while meeting the steam demand, so that the electrical load from the steam turbine to the power grid can be increased more quickly. In this way, while ensuring the accuracy of electrical load regulation, the rate and amplitude of electrical load response can be maximized to meet usage requirements.

[0018] Additional aspects and advantages of the present disclosure will be given in part in the description below and in part will be obvious from the description below, or will be learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present disclosure will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0020] Figure 1 1 is a structural diagram of a load-adjustable back pressure unit proposed in one embodiment of the present disclosure;

[0021] in, Figure 1 The dotted line in is the circuit. Figure 1 The solid lines in the figure are pipelines;

[0022] As shown in the figure: 1. Steam turbine, 2. Electric heater, 3. Low-temperature tank, 4. High-temperature tank, 5. Heat exchanger, 6. Power grid, 7. Steam-using equipment, 8. Boiler, 9. High-pressure cylinder, 10. Medium-pressure cylinder, 11. Low-pressure cylinder, 12. Generator, 13. First regulating valve, 14. First one-way valve, 15. Second regulating valve, 16. Second one-way valve, 17. Deaerator, 18. First pump body, 19. Third regulating valve, 20. Second pump body, 21. High-pressure heater, 22. Heating tank, 23. Heating pipe, 24. Third pump body, 25. Fourth pump body, 26. Fourth regulating valve, 27. Fifth regulating valve. DETAILED DESCRIPTION

[0023] The following describes in detail embodiments of the present disclosure, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present disclosure and are not to be construed as limiting the present disclosure. On the contrary, the embodiments of the present disclosure include all variations, modifications, and equivalents that fall within the spirit and scope of the appended claims.

[0024] like Figure 1As shown, the embodiment of the present disclosure proposes a load-adjustable back pressure unit, including a steam turbine 1, an electric heater 2, a low-temperature tank 3, a high-temperature tank 4 and a heat exchanger 5, the power output end of the steam turbine 1 is connected to the power input end of the power grid 6, the steam output end of the steam turbine 1 is connected to the steam input end of the steam-consuming equipment 7, the power input end of the electric heater 2 is connected to the power output end of the steam turbine 1, the molten salt output end of the low-temperature tank 3 is connected to the molten salt input end of the electric heater 2, the molten salt input end of the high-temperature tank 4 is connected to the molten salt output end of the electric heater 2, the hot side passage input end of the heat exchanger 5 is connected to the molten salt output end of the high-temperature tank 4, the hot side passage output end of the heat exchanger 5 is connected to the molten salt input end of the low-temperature tank 3, the cold side passage input end of the heat exchanger 5 is connected to the feed water input end of the steam turbine 1, and the cold side passage output end of the heat exchanger 5 is connected to the steam input end of the steam-consuming equipment 7 and the steam input end of the steam turbine 1.

[0025] It can be understood that when the electricity demand of the power grid 6 is relatively small, the steam turbine 1 transmits electricity to the power grid 6 while transmitting steam to the steam-consuming equipment 7, so as to meet the steam demand of the steam-consuming equipment 7 and the electricity demand of the power grid 6 at the same time. Moreover, the power of the electric heater 2 increases rapidly and gradually to consume the excess electricity of the steam turbine 1. When the low-temperature molten salt in the low-temperature tank 3 passes through the electric heater 2, the electric heater 2 converts electrical energy into thermal energy and converts the low-temperature molten salt into high-temperature molten salt to be stored in the high-temperature tank 4.

[0026] When the electricity demand of the power grid 6 is large, more steam in the steam turbine 1 is used to generate electricity to meet the electricity demand of the power grid 6, and less steam is transmitted to the steam-consuming equipment 7. At the same time, the power of the electric heater 2 is rapidly and gradually reduced to increase the electric energy transmitted by the steam turbine 1 to the power grid 6. Moreover, when the high-temperature molten salt in the high-temperature tank 4 passes through the hot side passage of the heat exchanger 5 and the feed water of the steam turbine 1 passes through the cold side passage of the heat exchanger 5, the high-temperature molten salt is converted into low-temperature molten salt and the feed water is heated into steam to cooperate with the steam output by the steam turbine 1 for use by the steam-consuming equipment 7, thereby meeting the steam demand of the power grid 6 while meeting the steam demand of the steam-consuming equipment 7.

[0027] When the electricity demand of the power grid 6 is extremely high, all the steam in the steam turbine 1 is used to generate electricity for use in the power grid 6. At the same time, the power of the electric heater 2 is gradually reduced to increase the electric energy transmitted by the steam turbine 1 to the power grid 6. Moreover, when the high-temperature molten salt in the high-temperature tank 4 passes through the hot side passage of the heat exchanger 5 and the feed water of the steam turbine 1 passes through the cold side passage of the heat exchanger 5, the high-temperature molten salt is converted into low-temperature molten salt and the feed water is heated into steam. A larger part of the steam is transmitted to the steam-consuming equipment 7 to meet the steam demand of the steam-consuming equipment 7, and the remaining part of the steam is transmitted to the steam turbine 1 to increase the power generation of the steam turbine 1, thereby meeting the electricity demand of the power grid 6.

[0028] Therefore, using the electric heater 2 to heat the molten salt as a controllable load of the steam turbine 1 can not only improve the peak-shaving capacity of the steam turbine 1, but also reduce the power of the electric heater 2 so that the electric load from the steam turbine 1 to the power grid 6 can be quickly increased. At the same time, the heat stored in the molten salt can be used to generate steam, thereby increasing the power generation of the steam turbine 1 while meeting the steam demand, so that the electric load from the steam turbine 1 to the power grid 6 can be increased faster. Therefore, while ensuring the accuracy of electric load regulation, the rate and amplitude of electric load response are maximized to meet usage requirements.

[0029] It should be noted that the output power of the steam turbine 1 is equal to the sum of the input power of the power grid 6 and the input power of the electric heater 2. Therefore, when the output power of the steam turbine 1 is increased and the input power of the electric heater 2 is reduced, the increase in the input power of the power grid 6 can be greater, and since the power of the electric heater 2 is easy to adjust, the increase rate of the input power of the power grid 6 can be greater.

[0030] When the power of the electric heater 2 decreases rapidly and gradually, the molten salt flow from the low-temperature tank 3 to the electric heater 2 should be reduced to keep the molten salt temperature from the electric heater 2 to the high-temperature tank 4 constant. When the power of the electric heater 2 decreases rapidly and gradually until it reaches zero, the passages from the low-temperature tank 3 to the electric heater 2 and from the electric heater 2 to the high-temperature tank 4 can be closed.

[0031] The low temperature tank 3 is used to store low temperature molten salt, and the high temperature tank 4 is used to store high temperature molten salt. The specific types of the low temperature tank 3 and the high temperature tank 4 can be set according to actual needs and are not limited to this.

[0032] The heat exchanger 5 includes a hot side passage and a cold side passage, and heat is exchanged between the hot side passage and the cold side passage. The heat exchange method can be set according to actual needs. For example, the hot side passage and the cold side passage can indirectly exchange heat through a medium; the hot side passage and the cold side passage can directly exchange heat through contact.

[0033] The power grid 6 refers to the electricity consumption network, which is an integral body consisting of various voltage substations, transmission and distribution lines, etc. The power grid 6 includes three units: transformation, transmission, and distribution.

[0034] The specific type of the steam-using equipment 7 can be set according to actual needs and is not limited thereto.

[0035] like Figure 1As shown, in some embodiments, the steam turbine 1 includes a boiler 8, a high-pressure cylinder 9, an intermediate-pressure cylinder 10, a low-pressure cylinder 11 and a generator 12, the feed water input end of the boiler 8 is connected to the cold side passage input end of the heat exchanger 5, the steam input end of the high-pressure cylinder 9 is connected to the main steam output end of the boiler 8, the steam output end of the high-pressure cylinder 9 is connected to the reheat steam input end of the boiler 8, the steam input end of the intermediate-pressure cylinder 10 is connected to the reheat steam output end of the boiler 8 and the cold side passage output end of the heat exchanger 5, the steam output end of the intermediate-pressure cylinder 10 is connected to the steam input end of the steam-consuming equipment 7, the steam input end of the low-pressure cylinder 11 is connected to the steam output end of the intermediate-pressure cylinder 10, the power input end of the generator 12 is connected to the power output ends of the high-pressure cylinder 9, the intermediate-pressure cylinder 10 and the low-pressure cylinder 11, and the electric energy output end of the generator 12 is connected to the electric energy input end of the power grid 6 and the electric energy input end of the electric heater 2.

[0036] It can be understood that the boiler 8 heats the feed water into main steam and transports it to the high-pressure cylinder 9. After the steam in the high-pressure cylinder 9 does work, it enters the boiler 8 to be heated into reheated steam. The reheated steam is transported to the intermediate-pressure cylinder 10 to do work. After the steam has done work in the intermediate-pressure cylinder 10, it enters the low-pressure cylinder 11 to continue doing work. The work done by the steam in the high-pressure cylinder 9, the intermediate-pressure cylinder 10 and the low-pressure cylinder 11 drives the generator 12 to generate electricity.

[0037] Among them, the electricity generated by the generator 12 is used to supply power to the power grid 6 and the electric heater 2. At the same time, when the power demand of the power grid 6 is relatively small, part of the steam after work in the intermediate pressure cylinder 10 supplies steam to the steam-consuming equipment 7. When the power demand of the power grid 6 is relatively large, part of the steam after work in the intermediate pressure cylinder 10 and the steam output from the hot side passage of the heat exchanger 5 jointly supply steam to the steam-consuming equipment 7. When the power demand of the power grid 6 is extremely large, all the steam after work in the intermediate pressure cylinder 10 enters the low pressure cylinder 11 to perform work, and the steam output from the hot side passage of the heat exchanger 5 not only supplies steam to the steam-consuming equipment 7, but also enters the intermediate pressure cylinder 10 to perform work, so as to increase the power generation of the generator 12.

[0038] It should be noted that the boiler 8 includes a main steam passage and a reheat steam passage, and the boiler 8 is used to burn fuel to heat the feed water and the steam after the high-pressure cylinder 9 has done work.

[0039] The high-pressure cylinder 9, the medium-pressure cylinder 10 and the low-pressure cylinder 11 use steam to do work. The specific types of the high-pressure cylinder 9, the medium-pressure cylinder 10 and the low-pressure cylinder 11 can be set according to actual needs and are not limited to this.

[0040] The generator 12 is used to convert mechanical energy into electrical energy. The specific type of the generator 12 can be set according to actual needs and is not limited to this.

[0041] like Figure 1As shown, in some embodiments, the back pressure unit further includes a first regulating valve 13, a first one-way valve 14, a second regulating valve 15 and a second one-way valve 16. The first regulating valve 13 is arranged on the pipeline between the steam input end of the intermediate pressure cylinder 10 and the output end of the cold side passage of the heat exchanger 5, the first one-way valve 14 is arranged on the pipeline between the steam input end of the intermediate pressure cylinder 10 and the output end of the cold side passage of the heat exchanger 5, the first one-way valve 14 is conducted in the direction from the output end of the cold side passage of the heat exchanger 5 to the steam input end of the intermediate pressure cylinder 10, the second regulating valve 15 is arranged on the pipeline between the steam output end of the intermediate pressure cylinder 10 and the steam input end of the steam-consuming equipment 7, the second one-way valve 16 is arranged on the pipeline between the steam output end of the intermediate pressure cylinder 10 and the steam input end of the steam-consuming equipment 7, the second one-way valve 16 is conducted in the direction from the steam output end of the intermediate pressure cylinder 10 to the steam input end of the steam-consuming equipment 7, wherein the switching states of the first regulating valve 13 and the second regulating valve 15 are opposite.

[0042] It can be understood that when the electricity demand of the power grid 6 is relatively small, the second regulating valve 15 is opened and the first regulating valve 13 is closed. At this time, part of the steam after the work of the intermediate pressure cylinder 10 is transported to the steam-consuming equipment 7. When the electricity demand of the power grid 6 is relatively large, the second regulating valve 15 is opened and the first regulating valve 13 is closed. At this time, part of the steam after the work of the intermediate pressure cylinder 10 is transported to the steam-consuming equipment 7. When the electricity demand of the power grid 6 is extremely large, the first regulating valve 13 is opened and the second regulating valve 15 is closed. At this time, part of the steam output from the cold side passage of the heat exchanger 5 is transported to the intermediate pressure cylinder 10.

[0043] By setting the first regulating valve 13 and the second regulating valve 15, it is not only convenient to control the on-off between the intermediate pressure cylinder 10, the heat exchanger 5 and the steam-consuming equipment 7, but also convenient to adjust the steam flow between the intermediate pressure cylinder 10, the heat exchanger 5 and the steam-consuming equipment 7, thereby making the adjustment of the electrical load of the back pressure unit more accurate and convenient.

[0044] Among them, through the setting of the first one-way valve 14 and the second one-way valve 16, part of the steam output from the cold side passage of the heat exchanger 5 can be stably transported to the intermediate pressure cylinder 10, and part of the steam after the intermediate pressure cylinder 10 works can be stably transported to the steam-consuming equipment 7, avoiding the problem of reverse steam transportation and ensuring the precise regulation of the electrical load of the back-pressure unit.

[0045] It should be noted that the specific types of the first regulating valve 13 and the second regulating valve 15 can be set according to actual needs. For example, the first regulating valve 13 and the second regulating valve 15 can be electric regulating valves; the first regulating valve 13 and the second regulating valve 15 can be manual regulating valves.

[0046] In order to make the regulation of the electrical load of the back pressure unit more precise, regulating valves can be added to each passage. For example, a regulating valve is provided at the output end of the hot side passage of the heat exchanger 5, and a regulating valve is provided at the steam input end of the steam-consuming equipment 7. These two regulating valves are used to cooperate with the first regulating valve 13 or the second regulating valve 15 to accurately control the on-off and steam flow between the intermediate pressure cylinder 10, the heat exchanger 5 and the steam-consuming equipment 7.

[0047] The specific types of the first one-way valve 14 and the second one-way valve 16 can be set according to actual needs and are not limited thereto.

[0048] like Figure 1 As shown, in some embodiments, the steam turbine 1 further includes a deaerator 17, the feed water input end of the deaerator 17 is connected to the steam output end of the low-pressure cylinder 11, and the feed water output end of the deaerator 17 is connected to the feed water input end of the boiler 8 and the cold side passage input end of the heat exchanger 5.

[0049] It can be understood that the steam in the low-pressure cylinder 11 enters the deaerator 17 for deoxygenation after condensation, and the deoxygenated condensate is supplied to the boiler 8 and the heat exchanger 5, which not only realizes the water circulation of the back-pressure unit and reduces the operating cost of the back-pressure unit, but also reduces the corrosion of various equipment and pipelines in the back-pressure unit by deoxygenating the condensate, thereby effectively extending the service life of the back-pressure unit.

[0050] It should be noted that the specific type of the deaerator 17 can be set according to actual needs and is not limited thereto.

[0051] The steam turbine 1 also includes a condenser, a low-pressure heater, etc., wherein the hot side passage input end of the condenser is connected to the steam output end of the low-pressure cylinder 11, the hot side passage output end of the condenser is connected to the feed water input end of the deaerator 17, and cooling water is introduced into the cold side passage of the condenser.

[0052] like Figure 1 As shown, in some embodiments, the back pressure unit also includes a first pump body 18 and a third regulating valve 19. The first pump body 18 is arranged on the pipeline between the water supply output end of the deaerator 17 and the cold side passage input end of the heat exchanger 5. The water supply input end of the first pump body 18 is connected to the water supply output end of the deaerator 17, and the water supply output end of the first pump body 18 is connected to the cold side passage input end of the heat exchanger 5. The third regulating valve 19 is arranged on the pipeline between the water supply output end of the deaerator 17 and the water supply input end of the first pump body 18.

[0053] It can be understood that when the electricity demand of the power grid 6 is relatively small, the first pump body 18 and the third regulating valve 19 are both closed, and when the electricity demand of the power grid 6 is relatively large and extremely large, the first pump body 18 and the third regulating valve 19 are both opened. Therefore, through the setting of the third regulating valve 19 and the first pump body 18, it is not only convenient to control the on-off between the deaerator 17 and the heat exchanger 5, but also convenient to adjust the water feed flow between the deaerator 17 and the heat exchanger 5, thereby making the adjustment of the electrical load of the back pressure unit more accurate and convenient.

[0054] It should be noted that when the electricity demand of the power grid 6 is large, the opening of the third regulating valve 19 and the speed of the first pump body 18 are both small. When the electricity demand of the power grid 6 is extremely large, the opening of the third regulating valve 19 and the speed of the first pump body 18 are both large.

[0055] The specific type of the third regulating valve 19 can be set according to actual needs. For example, the third regulating valve 19 can be an electric regulating valve; the third regulating valve 19 can be a manual regulating valve.

[0056] The specific type of the first pump body 18 can be set according to actual needs and is not limited thereto.

[0057] like Figure 1 As shown, in some embodiments, the steam turbine 1 further includes a second pump body 20 and a high-pressure heater 21, the feed water input end of the second pump body 20 is connected to the feed water output end of the deaerator 17, the hot side passage input end of the high-pressure cylinder 9 and the steam output end of the intermediate-pressure cylinder 10 are connected, the hot side passage output end of the high-pressure heater 21 is connected to the feed water input end of the second pump body 20, the cold side passage input end of the high-pressure heater 21 is connected to the feed water output end of the second pump body 20, and the cold side passage output end of the high-pressure heater 21 is connected to the feed water input end of the boiler 8.

[0058] It can be understood that, through the setting of the second pump body 20, the feed water output by the deaerator 17 can be pressurized and transported to the boiler 8 to ensure the stable operation of the back pressure unit. Through the setting of the high-pressure heater 21, the steam after work in the high-pressure cylinder 9 and the medium-pressure cylinder 10 is used to preheat the feed water output by the deaerator 17, thereby reducing the fuel loss of the boiler 8 and improving the heating efficiency of the boiler 8.

[0059] It should be noted that the specific type of the second pump body 20 can be set according to actual needs and is not limited to this.

[0060] The specific type of the high-pressure heater 21 can be set according to actual needs and is not limited thereto.

[0061] In order to make the regulation of the electrical load of the back pressure unit more precise, regulating valves can be added to each passage. For example, a regulating valve is provided at the water feed output end of the deaerator 17. The regulating valve is used to cooperate with the third regulating valve 19 to accurately control the on-off and water feed flow between the deaerator 17, the boiler 8, and the heat exchanger 5.

[0062] In some embodiments, the back pressure unit also includes a transformer and a power regulator, the power input end of the transformer is connected to the power output end of the generator 12, the power input end of the power regulator is connected to the power output end of the transformer, and the power output end of the power regulator is connected to the power input end of the electric heater 2.

[0063] It can be understood that the transformer converts the electric energy output by the generator 12 into a voltage transformer, and the power regulator adjusts the power of the electric energy output by the transformer. Therefore, through the setting of the transformer and the power regulator, not only the power supply to the electric heater 2 is realized, but also the power of the electric heater 2 is easily adjusted, making the electric load adjustment of the back pressure unit more accurate and convenient.

[0064] It should be noted that the specific type of the transformer can be set according to actual needs and is not limited to this.

[0065] The power regulator is a panel-mounted power adjustment unit that uses thyristors and their trigger control circuits to adjust the load power. The specific type of the power regulator can be set according to actual needs and is not limited to this.

[0066] like Figure 1 As shown, in some embodiments, the electric heater 2 includes a heating tank 22 and a heating tube 23, the molten salt input end of the heating tank 22 is connected to the molten salt output end of the low-temperature tank 3, the molten salt output end of the heating tank 22 is connected to the molten salt input end of the high-temperature tank 4, the heating tube 23 is arranged in the heating tank 22, and the power input end of the heating tube 23 is connected to the power output end of the power regulator.

[0067] It can be understood that the generator 12 supplies power to the heating tube 23 so that the heating tube 23 converts electrical energy into thermal energy. After the low-temperature molten salt in the low-temperature tank 3 enters the heating tank 22, the heating tube 23 heats the low-temperature molten salt into high-temperature molten salt. The high-temperature molten salt enters the high-temperature tank 4 from the heating tank 22 for storage, thereby realizing the conversion and storage of electrical energy.

[0068] It should be noted that the heating tank 22 is used for the transfer of molten salt. The specific type of the heating tank 22 can be set according to actual needs and is not limited to this.

[0069] The heating tube 23 is used to heat the molten salt. The specific type of the heating tube 23 can be set according to actual needs and is not limited to this.

[0070] like Figure 1As shown, in some embodiments, the back pressure unit also includes a third pump body 24 and a fourth pump body 25. The third pump body 24 is arranged on the pipeline between the molten salt output end of the low-temperature tank 3 and the molten salt input end of the electric heater 2. The molten salt input end of the third pump body 24 is connected to the molten salt output end of the low-temperature tank 3, and the molten salt output end of the third pump body 24 is connected to the molten salt input end of the electric heater 2. The fourth pump body 25 is arranged on the pipeline between the hot side passage input end of the heat exchanger 5 and the molten salt output end of the high-temperature tank 4. The molten salt input end of the fourth pump body 25 is connected to the molten salt output end of the high-temperature tank 4, and the molten salt output end of the fourth pump body 25 is connected to the hot side passage input end of the heat exchanger 5.

[0071] It can be understood that the third pump body 24 pressurizes the molten salt in the low-temperature tank 3 and transports it to the electric heater 2, and the fourth pump body 25 pressurizes the molten salt in the high-temperature tank 4 and transports it to the heat exchanger 5. Therefore, through the setting of the third pump body 24 and the fourth pump body 25, the stable circulation of the molten salt between the low-temperature tank 3, the electric heater 2, the high-temperature tank 4 and the heat exchanger 5 is guaranteed, and the stable storage of electric energy and the stable heating of the boiler 8 feed water are guaranteed.

[0072] It should be noted that the specific types of the third pump body 24 and the fourth pump body 25 can be set according to actual needs and are not limited thereto.

[0073] like Figure 1 As shown, in some embodiments, the back pressure unit also includes a fourth regulating valve 26 and a fifth regulating valve 27. The fourth regulating valve 26 is arranged on the pipeline between the molten salt output end of the third pump body 24 and the molten salt input end of the electric heater 2, and the fifth regulating valve 27 is arranged on the pipeline between the molten salt output end of the fourth pump body 25 and the hot side passage input end of the heat exchanger 5.

[0074] It is understandable that, according to the power demand of the power grid 6, when the electric heater 2 is running, the fourth regulating valve 26 and the third pump body 24 are both opened. When the power of the electric heater 2 is rapidly and gradually reduced to zero, the fourth regulating valve 26 and the third pump body 24 are both closed. When the power demand of the power grid 6 is relatively small, the fifth regulating valve 27 and the fourth pump body 25 are both closed. When the power demand of the power grid 6 is relatively large and extremely large, the fifth regulating valve 27 and the fourth pump body 25 are both opened. Thus, by setting the fourth regulating valve 26 and the fifth regulating valve 27, it is not only convenient to control the on-off between the low-temperature tank 3 and the electric heater 2 and between the high-temperature tank 4 and the heat exchanger 5, but also convenient to adjust the molten salt flow between the low-temperature tank 3 and the electric heater 2 and between the high-temperature tank 4 and the heat exchanger 5, thereby making the adjustment of the electrical load of the backpressure unit more accurate and convenient.

[0075] It should be noted that the specific types of the fourth regulating valve 26 and the fifth regulating valve 27 can be set according to actual needs. For example, the fourth regulating valve 26 and the fifth regulating valve 27 can be electric regulating valves; the fourth regulating valve 26 and the fifth regulating valve 27 can be manual regulating valves.

[0076] In the description of the present disclosure, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. In addition, in the description of the present disclosure, unless otherwise specified, the meaning of "plurality" is two or more.

[0077] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present disclosure includes additional implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present disclosure belong.

[0078] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0079] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A load-adjustable back pressure unit, characterized in that: include: A steam turbine, wherein the power output terminal of the steam turbine is connected to the power input terminal of the power grid, and the steam output terminal of the steam turbine is connected to the steam input terminal of the steam-consuming equipment; an electric heater, wherein the power input end of the electric heater is connected to the power output end of the steam turbine; A low-temperature tank, wherein the molten salt output end of the low-temperature tank is connected to the molten salt input end of the electric heater; A high-temperature tank, wherein the molten salt input end of the high-temperature tank is connected to the molten salt output end of the electric heater; a heat exchanger, wherein the hot side passage input end of the heat exchanger is connected to the molten salt output end of the high temperature tank, the hot side passage output end of the heat exchanger is connected to the molten salt input end of the low temperature tank, the cold side passage input end of the heat exchanger is connected to the feed water input end of the steam turbine, and the cold side passage output end of the heat exchanger is connected to the steam input end of the steam-consuming equipment and the steam input end of the steam turbine; Wherein, the steam turbine includes: a boiler, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder and a generator, the feed water input end of the boiler is connected to the cold side passage input end of the heat exchanger, the steam input end of the high-pressure cylinder is connected to the main steam output end of the boiler, the steam output end of the high-pressure cylinder is connected to the reheat steam input end of the boiler, the steam input end of the intermediate-pressure cylinder is connected to the reheat steam output end of the boiler and the cold side passage output end of the heat exchanger, the steam output end of the intermediate-pressure cylinder is connected to the steam input end of the steam-consuming equipment, the steam input end of the low-pressure cylinder is connected to the steam output end of the intermediate-pressure cylinder, the power input end of the generator is connected to the power output ends of the high-pressure cylinder, the intermediate-pressure cylinder and the low-pressure cylinder, and the electric energy output end of the generator is connected to the electric energy input end of the power grid and the electric energy input end of the electric heater; The back pressure unit further includes: a first regulating valve, a first non-return valve, a second regulating valve and a second non-return valve, the first regulating valve being arranged on a pipeline between the intermediate pressure cylinder steam input end and the output end of the cold side passage of the heat exchanger, the first non-return valve being arranged on a pipeline between the intermediate pressure cylinder steam input end and the output end of the cold side passage of the heat exchanger, the first non-return valve being conducted in a direction from the output end of the cold side passage of the heat exchanger to the steam input end of the intermediate pressure cylinder, the second regulating valve being arranged on a pipeline between the steam output end of the intermediate pressure cylinder and the steam input end of the steam-consuming equipment, the second non-return valve being arranged on a pipeline between the steam output end of the intermediate pressure cylinder and the steam input end of the steam-consuming equipment, the second non-return valve being conducted in a direction from the steam output end of the intermediate pressure cylinder to the steam input end of the steam-consuming equipment, wherein the switching states of the first regulating valve and the second regulating valve are opposite; When the power demand of the power grid is relatively low, the second regulating valve is opened and the first regulating valve is closed, the steam turbine transmits steam to the steam-consuming equipment and simultaneously transmits electric energy to the power grid, the power of the electric heater is gradually increased, the electric heater converts electric energy into heat energy, and converts low-temperature molten salt into high-temperature molten salt to be stored in the high-temperature tank; When the power demand of the power grid is high, the second regulating valve is opened and the first regulating valve is closed, the proportion of steam used for power generation in the steam turbine is greater than the proportion of steam delivered to the steam-consuming equipment, the power of the electric heater is gradually reduced, the high-temperature molten salt is converted into low-temperature molten salt and the feed water is heated into steam, which is then delivered to the steam-consuming equipment in conjunction with the steam output of the steam turbine; When the power demand of the power grid is at a maximum, the first regulating valve is opened and the second regulating valve is closed, all the steam in the steam turbine is used for power generation, the power of the electric heater is gradually reduced, the high-temperature molten salt is converted into low-temperature molten salt and the feed water is heated into steam, part of the steam is delivered to the steam-consuming equipment, and the remaining part is delivered to the steam turbine; The back pressure unit further comprises: a transformer and a power regulator, wherein the power input end of the transformer is connected to the power output end of the generator, the power input end of the power regulator is connected to the power output end of the transformer, and the power output end of the power regulator is connected to the power input end of the electric heater; The electric heater includes: a heating tank and a heating tube, the molten salt input end of the heating tank is connected to the molten salt output end of the low-temperature tank, the molten salt output end of the heating tank is connected to the molten salt input end of the high-temperature tank, the heating tube is arranged in the heating tank, and the power input end of the heating tube is connected to the power output end of the power regulator.

2. The load-adjustable back pressure unit according to claim 1, characterized in that: The steam turbine further comprises: A deaerator, wherein the water feed input end of the deaerator is connected to the steam output end of the low-pressure cylinder, and the water feed output end of the deaerator is connected to the water feed input end of the boiler and the cold side passage input end of the heat exchanger.

3. The load-adjustable back pressure unit according to claim 2, characterized in that: The back pressure unit also includes: A first pump body, the first pump body is arranged on the pipeline between the water supply output end of the deaerator and the cold side passage input end of the heat exchanger, the water supply input end of the first pump body is connected to the water supply output end of the deaerator, and the water supply output end of the first pump body is connected to the cold side passage input end of the heat exchanger; A third regulating valve is provided on a pipeline between the water supply output end of the deaerator and the water supply input end of the first pump body.

4. The load-adjustable back pressure unit according to claim 2, characterized in that: The steam turbine further comprises: a second pump body, wherein a water feed input end of the second pump body is connected to a water feed output end of the deaerator; A high-pressure heater, the hot side passage input end of the high-pressure heater is connected to the steam output end of the high-pressure cylinder and the steam output end of the medium-pressure cylinder, the hot side passage output end of the high-pressure heater is connected to the water feed input end of the second pump body, the cold side passage input end of the high-pressure heater is connected to the water feed output end of the second pump body, and the cold side passage output end of the high-pressure heater is connected to the water feed input end of the boiler.

5. The load-adjustable back pressure unit according to any one of claims 1 to 4, characterized in that: The back pressure unit also includes: a third pump body, the third pump body being arranged on a pipeline between the molten salt output end of the cryogenic tank and the molten salt input end of the electric heater, the molten salt input end of the third pump body being connected to the molten salt output end of the cryogenic tank, and the molten salt output end of the third pump body being connected to the molten salt input end of the electric heater; The fourth pump body is arranged on the pipeline between the hot side passage input end of the heat exchanger and the molten salt output end of the high-temperature tank. The molten salt input end of the fourth pump body is connected to the molten salt output end of the high-temperature tank, and the molten salt output end of the fourth pump body is connected to the hot side passage input end of the heat exchanger.

6. The load-adjustable back pressure unit according to claim 5, characterized in that: The back pressure unit also includes: a fourth regulating valve, the fourth regulating valve being arranged on a pipeline between the molten salt output end of the third pump body and the molten salt input end of the electric heater; A fifth regulating valve is provided on the pipeline between the molten salt output end of the fourth pump body and the input end of the hot side passage of the heat exchanger.

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