Fused salt auxiliary system and method for gas turbine

Abstract

The invention discloses a molten salt auxiliary system and method for a gas turbine, an outlet of the gas turbine is communicated with a flue gas inlet of a waste heat boiler and a heat release side inlet of a molten salt module, and a main steam outlet of the waste heat boiler is communicated with an inlet of a high-pressure cylinder through a high-pressure main steam valve; an outlet of the high-pressure cylinder is communicated with a reheating side inlet of the waste heat boiler through a high-emission check valve, a reheating side outlet of the waste heat boiler is communicated with an inlet of the medium-pressure cylinder through a medium-pressure main steam valve, and a steam outlet of the medium-pressure cylinder is communicated with a low-pressure steam outlet of the waste heat boiler and an inlet of the low-pressure main steam valve. A steam outlet of the molten salt module communicates with a steam outlet of the high-pressure cylinder through a high-pressure cylinder reverse warming valve, the steam outlet of the molten salt module communicates with a reheating side outlet of the waste heat boiler through a medium-pressure cylinder pre-warming valve, and the system and method are short in pre-warming time, capable of reducing energy consumption of natural gas and good in reliable operability and energy-saving effect.

Description

Technical Field

[0001] The invention belongs to the technical field of energy-saving transformation of gas turbines and relates to a molten salt auxiliary system and method for gas turbines. Background Art

[0002] When the existing gas turbine is working, the flue gas is directly sent into the chimney for discharge after being treated. At the same time, when the turbine is shut down and started, it is necessary to preheat the turbine first. The preheating time is relatively long. At the same time, a large amount of natural gas is consumed during the preheating process, which leads to increased startup costs and poor operability and energy-saving effects. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a molten salt auxiliary system and method for a gas turbine. The system and method have a short preheating time, can reduce the energy consumption of natural gas, and have good reliable operability and energy-saving effect.

[0004] To achieve the above-mentioned object, the present invention discloses a molten salt auxiliary system for a gas turbine, including a gas turbine, a waste heat boiler, a molten salt module, a high-pressure main steam valve, a high-pressure cylinder, a high-exhaust check valve, a medium-pressure main steam valve, a medium-pressure cylinder, a low-pressure main steam valve, a molten salt module, a high-pressure cylinder reverse warming valve and a medium-pressure cylinder pre-warming valve;

[0005] The outlet of the gas turbine is connected with the flue gas inlet of the waste heat boiler and the heat release side inlet of the molten salt module, the main steam outlet of the waste heat boiler is connected with the inlet of the high-pressure cylinder through the high-pressure main steam valve, the outlet of the high-pressure cylinder is connected with the reheat side inlet of the waste heat boiler through the high-exhaust check valve, the reheat side outlet of the waste heat boiler is connected with the inlet of the medium-pressure cylinder through the medium-pressure main steam valve, the steam outlet of the medium-pressure cylinder is connected with the low-pressure steam outlet of the waste heat boiler and the inlet of the low-pressure main steam valve, the steam outlet of the molten salt module is connected with the steam outlet of the high-pressure cylinder through the high-pressure cylinder reverse warming valve, and the steam outlet of the molten salt module is connected with the reheat side outlet of the waste heat boiler through the medium-pressure cylinder preheating valve.

[0006] Furthermore, it also includes an air input pipeline and a natural gas input pipeline, and the air input pipeline and the natural gas input pipeline are connected to the inlet of the gas turbine.

[0007] Furthermore, it also includes a chimney, and the flue gas outlet of the waste heat boiler and the heat release side outlet of the molten salt module are connected to the inlet of the chimney.

[0008] Furthermore, it also includes a low-pressure cylinder, a condenser and a condensate pump. The outlet of the low-pressure main steam valve is connected to the inlet of the low-pressure cylinder, and the outlet of the low-pressure cylinder is connected to the water inlet of the waste heat boiler via the condenser and the condensate pump in turn.

[0009] Furthermore, the outlet of the condensate pump is connected to the heat absorption side inlet of the molten salt module through the molten salt user water inlet gate.

[0010] Furthermore, the reheat side outlet of the waste heat boiler is connected to the condenser inlet via a center side hydraulic door.

[0011] Furthermore, the inlet of the low-pressure main steam valve is connected to the inlet of the condenser through the low bypass hydraulic valve; the main steam outlet of the waste heat boiler is connected to the reheat side inlet of the waste heat boiler through the high bypass hydraulic valve.

[0012] Further, the molten salt module includes a hot tank, a hot tank outlet door, a superheater, an evaporator, a cold tank, a cold tank outlet door and a flue gas-molten salt heat exchanger, wherein the outlet of the hot tank is sequentially connected to the inlet of the cold tank via the hot tank outlet door, the heat release side of the superheater, and the heat release side of the evaporator, and the outlet of the cold tank is sequentially connected to the inlet of the hot tank via the cold tank outlet door and the molten salt side of the flue gas-molten salt heat exchanger;

[0013] The flue gas outlet of the gas turbine is connected to the flue gas side inlet of the flue gas-molten salt heat exchanger through the gas turbine exhaust diverter valve, and the flue gas side outlet of the flue gas-molten salt heat exchanger is connected to the inlet of the chimney;

[0014] The outlet of the condensate pump is connected to the heat absorption side inlet of the evaporator through the molten salt user water inlet gate, the heat absorption side outlet of the evaporator is connected to the heat absorption side inlet of the superheater, and the heat absorption side outlet of the superheater is connected to the inlet of the medium pressure cylinder preheating valve and the high pressure cylinder.

[0015] Furthermore, the drain port of the low-pressure cylinder is connected to the inlet of the condenser through the low-pressure cylinder drain gate, the drain port of the medium-pressure cylinder is connected to the inlet of the condenser through the medium-pressure cylinder drain gate, and the drain port of the high-pressure cylinder is connected to the inlet of the condenser through the high-pressure cylinder drain gate.

[0016] The molten salt auxiliary method for a gas turbine described in the present invention comprises the following steps: a portion of the flue gas exhausted by the gas turbine is sent into a molten salt module, and after the gas turbine is shut down and waiting to be restarted, heat is released through the molten salt module to generate superheated steam, and the superheated steam is used to preheat the steam turbine in advance.

[0017] The present invention has the following beneficial effects:

[0018] During specific operation of the molten salt auxiliary system and method for a gas turbine described in the present invention, a separate path is arranged at the gas turbine exhaust pipe to flow into a heat storage module. Before the gas turbine is shut down, the molten salt stores part of the exhaust heat. When waiting to be restarted, the molten salt module can release heat to generate superheated steam, and the steam turbine can be preheated in advance. In this way, after the gas turbine is started with load, as long as the main steam and reheated steam meet the start-up requirements, the steam turbine can be directly connected to the grid to increase the load, reducing the energy loss of natural gas. After the transformation, the combined cycle performance can be effectively improved. The present invention has the characteristics of strong operability, flexible operation mode, and significant energy-saving effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 It is a structural diagram of the present invention;

[0021] Figure 2 It is a structural diagram of the molten salt module 6.

[0022] Among them, 1 is the gas turbine, 2 is the low-pressure cylinder, 3 is the medium-pressure cylinder, 4 is the high-pressure cylinder, 5 is the gas turbine exhaust diverter valve, 6 is the molten salt module, 7 is the waste heat boiler, 8 is the condensate pump, 9 is the condenser, 10 is the chimney, 11 is the high-pressure main steam valve, 12 is the high-pressure cylinder drain valve, 13 is the medium-pressure main steam valve, 14 is the medium-pressure cylinder drain valve, 15 is the low-pressure main steam valve, 16 is the low-pressure cylinder drain valve, 17 is the medium-pressure cylinder preheating valve, 18 is the high-pressure cylinder reverse warming valve, 19 is the high-exhaust check valve, 20 is the high-bypass hydraulic valve, 21 is the medium-bypass hydraulic valve, 22 is the low-bypass hydraulic valve, 23 is the molten salt user water inlet gate, 24 is the hot tank, 25 is the flue gas-molten salt heat exchanger, 26 is the cold tank outlet door, 27 is the cold tank, 28 is the evaporator, 29 is the superheater, and 30 is the hot tank outlet door. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0025] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0026] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0027] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0028] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0031] Embodiment 1

[0032] The molten salt auxiliary system for a fuel engine of the present invention comprises a gas turbine 1, a waste heat boiler 7, a molten salt module 6, a high-pressure main steam valve 11, a high-pressure cylinder 4, a high-exhaust check valve 19, a medium-pressure main steam valve 13, a medium-pressure cylinder 3, a low-pressure main steam valve 15, a molten salt module 6, a high-pressure cylinder reverse warming valve 18 and a medium-pressure cylinder preheating valve 17; the outlet of the gas turbine 1 is connected to the flue gas inlet of the waste heat boiler 7 and the heat release side inlet of the molten salt module 6, and the main steam outlet of the waste heat boiler 7 is connected to the inlet of the high-pressure cylinder 4 via the high-pressure main steam valve 11 The outlet of the high-pressure cylinder 4 is connected to the reheat side inlet of the waste heat boiler 7 through the high-discharge check valve 19, the reheat side outlet of the waste heat boiler 7 is connected to the inlet of the intermediate-pressure cylinder 3 through the intermediate-pressure main steam valve 13, the steam outlet of the intermediate-pressure cylinder 3 and the low-pressure steam outlet of the waste heat boiler 7 are connected to the inlet of the low-pressure main steam valve 15, the steam outlet of the molten salt module 6 is connected to the steam outlet of the high-pressure cylinder 4 through the high-pressure cylinder reverse warming valve 18, and the steam outlet of the molten salt module 6 is connected to the reheat side outlet of the waste heat boiler 7 through the intermediate-pressure cylinder preheating valve 17.

[0033] Correspondingly, the molten salt auxiliary method for a gas turbine described in the present invention comprises the following steps: part of the flue gas exhausted by the gas turbine 1 is sent into the molten salt module 6, and after the gas turbine 1 is shut down and waiting to be restarted, heat is released through the molten salt module 6 to generate superheated steam, and the superheated steam is used to preheat the steam turbine in advance.

[0034] Embodiment 2

[0035] refer to Figure 1 The molten salt auxiliary system for a gas turbine of the present invention comprises a gas turbine 1, a low-pressure cylinder 2, a medium-pressure cylinder 3, a high-pressure cylinder 4, a gas turbine exhaust diverter valve 5, a molten salt module 6, a waste heat boiler 7, a condensate pump 8, a condenser 9, a chimney 10, a high-pressure main steam valve 11, a high-pressure cylinder drain valve 12, a medium-pressure main steam valve 13, a medium-pressure cylinder drain valve 14, a low-pressure main steam valve 15, a low-pressure cylinder drain valve 16, a medium-pressure cylinder preheating valve 17, a high-pressure cylinder reverse warming valve 18, a high-discharge check valve 19, a high-bypass hydraulic valve 20, a medium-bypass hydraulic valve 21, a low-bypass hydraulic valve 22 and a molten salt user water inlet gate 23; the molten salt module 6 comprises a hot tank 24, a flue gas-molten salt heat exchanger 25, a cold tank outlet door 26, a cold tank 27, an evaporator 28, a superheater 29 and a hot tank outlet door 30;

[0036] The air input pipeline and the natural gas input pipeline are connected to the inlet of the gas turbine 1, the outlet of the gas turbine 1 is connected to the flue gas inlet of the waste heat boiler 7 and the heat release side inlet of the molten salt module 6, the flue gas outlet of the waste heat boiler 7 and the heat release side outlet of the molten salt module 6 are connected to the inlet of the chimney 10; the main steam outlet of the waste heat boiler 7 is connected to the inlet of the high-pressure cylinder 4 through the high-pressure main steam valve 11, the outlet of the high-pressure cylinder 4 is connected to the reheat side inlet of the waste heat boiler 7 through the high-discharge check valve 19, the reheat side outlet of the waste heat boiler 7 is connected to the inlet of the medium-pressure cylinder 3 through the medium-pressure main steam valve 13, the steam outlet of the medium-pressure cylinder 3 and the low-pressure steam outlet of the waste heat boiler 7 are connected to the inlet of the low-pressure main steam valve 15, and the outlet of the low-pressure main steam valve 15 is connected to the low-pressure The inlet of the low-pressure cylinder 2 is connected, the outlet of the low-pressure cylinder 2 is connected to the water inlet of the waste heat boiler 7 through the condenser 9 and the condensate pump 8 in turn, the outlet of the condensate pump 8 is connected to the heat absorption side inlet of the molten salt module 6 through the molten salt user water inlet gate 23, the steam outlet of the molten salt module 6 is connected to the steam outlet of the high-pressure cylinder 4 through the high-pressure cylinder reverse warming valve 18, the steam outlet of the molten salt module 6 is connected to the reheat side outlet of the waste heat boiler 7 through the medium-pressure cylinder preheating valve 17; the reheat side outlet of the waste heat boiler 7 is connected to the inlet of the condenser 9 through the medium bypass hydraulic valve 21; the inlet of the low-pressure main steam valve 15 is connected to the inlet of the condenser 9 through the low bypass hydraulic valve 22; the main steam outlet of the waste heat boiler 7 is connected to the reheat side inlet of the waste heat boiler 7 through the high bypass hydraulic valve 20.

[0037] As an embodiment of the present invention, the molten salt module 6 includes a hot tank 24, a hot tank outlet door 30, a superheater 29, an evaporator 28, a cold tank 27, a cold tank outlet door 26 and a flue gas-molten salt heat exchanger 25, wherein the outlet of the hot tank 24 is connected to the inlet of the cold tank 27 through the hot tank outlet door 30, the heat release side of the superheater 29, and the heat release side of the evaporator 28, and the outlet of the cold tank 27 is connected to the inlet of the hot tank 24 through the cold tank outlet door 26, the molten salt side of the flue gas-molten salt heat exchanger 25, and the hot tank 24. The flue gas outlet of the gas turbine 1 is connected to the flue gas side inlet of the flue gas-molten salt heat exchanger 25 through the gas turbine exhaust diverter valve 5, and the flue gas side outlet of the flue gas-molten salt heat exchanger 25 is connected to the inlet of the chimney 10; the outlet of the condensate pump 8 is connected to the heat absorption side inlet of the evaporator 28 through the molten salt user water inlet gate 23, the heat absorption side outlet of the evaporator 28 is connected to the heat absorption side inlet of the superheater 29, and the heat absorption side outlet of the superheater 29 is connected to the inlet of the medium-pressure cylinder preheating valve 17 and the high-pressure cylinder 4.

[0038] As an implementation scheme of the present invention, the drain port of the low-pressure cylinder 2 is connected to the inlet of the condenser 9 through a low-pressure cylinder drain gate 16 .

[0039] As an implementation scheme of the present invention, the drain port of the intermediate pressure cylinder 3 is connected to the inlet of the condenser 9 through the intermediate pressure cylinder drain gate 14 .

[0040] As an implementation scheme of the present invention, the drain port of the high-pressure cylinder 4 is connected to the inlet of the condenser 9 through a high-pressure cylinder drain gate 12 .

[0041] Accordingly, the molten salt auxiliary method for a gas turbine according to the present invention comprises the following steps:

[0042] Air enters the compressor, and the compressed air and natural gas burn in the combustion chamber to produce high-temperature flue gas. The high-temperature flue gas enters the gas turbine 1 to expand and do work. The exhaust gas of the gas turbine 1 enters the waste heat boiler 7 to heat the boiler feed water, forming main steam with different pressure parameters, which enter the high-pressure cylinder 4, the medium-pressure cylinder 3 and the low-pressure cylinder 2 respectively. The main steam enters the steam turbine unit to expand and do work. The exhaust steam of the steam turbine enters the condenser 9 to form condensed water, which is pressurized by the condensate pump 8 to the waste heat boiler 7, forming a steam-water cycle, and the heat of the condenser 9 is taken away by the circulating water.

[0043] After the system transformation, the exhaust pipe of the gas turbine is divided into one path to flow to the molten salt module 6. Before the gas unit is shut down, the gas turbine exhaust diverter valve 5 is opened. Figure 2 As shown, the low-temperature molten salt flows out from the cold tank 27, flows through the flue gas-molten salt heat exchanger 25 and is heated by the waste heat of the flue gas. After the heating is completed, the gas turbine exhaust diverter valve 5 is closed, the high-temperature molten salt is stored in the hot tank 24, and the flue gas is discharged through the chimney 10. Before the gas turbine 1 is ready to start again, the molten salt module 6 is put into use, and the molten salt can be used to heat the condensate in advance to generate superheated steam to preheat the cylinder.

[0044] The preheating process of the steam turbine cylinder is as follows: before the single gas turbine is connected to the grid, the molten salt user water inlet gate 23 is put into operation, so that part of the condensate is heated by the high-temperature molten salt released from the hot tank 24, and the condensate is heated into superheated steam after passing through the evaporator 28 and the superheater 29, and the steam pressure is about 1.5MPa. The high-pressure cylinder reverse warming valve 18 and the main body drain valve of each cylinder of the steam turbine unit are opened in advance, and the high-pressure main steam valve 11 and the high-discharge check valve 19 are confirmed to be closed, and the high-pressure cylinder 4 is reverse warmed to allow the warm cylinder steam to enter the high-pressure cylinder 4. The steam enters the drain system through the high-pressure cylinder drain gate 12 and is finally discharged to the condenser 9. When the cylinder body of the high-pressure cylinder 4 is preheated to about 150℃, the reverse warming is stopped and the high-pressure cylinder reverse warming valve 18 is closed. An electric heater is built into the hot tank 24. After the reverse warming of the high-pressure cylinder 4 is completed, the high-pressure cylinder reverse warming valve 18 is closed, and the medium-pressure cylinder preheating valve 17 is opened. Part of the power of the factory DC battery is used to heat the molten salt to raise the molten salt temperature to a higher temperature. The high-temperature molten salt then heats the condensate to produce superheated steam with a higher superheat degree. When the steam meets the parameters for the intermediate-pressure cylinder 3, the intermediate-pressure main steam valve 13 and the low-bypass hydraulic valve 22 are opened, and the low-pressure main steam valve 15 is closed. A certain opening is given to the intermediate-pressure main steam valve 13 through the speed control mode. , preheat the intermediate pressure cylinder 3 in stages, and finally maintain the turbine speed at 2800-3000r / min, fully warm up the machine, then close the intermediate pressure cylinder preheating valve 17 and the intermediate pressure main steam valve 13, and the turbine speed idling to the cranking speed. During the preheating of the intermediate pressure cylinder 3, the gas turbine can be connected to the grid with load at the same time, and the exhaust gas of the gas turbine 1 enters the waste heat boiler 7 to heat the boiler feed water to produce superheated steam of different pressures, ensuring that the high-pressure and medium-pressure superheated steam meet the turbine run-up parameters before the turbine speed idling to the cranking speed. In this way, after the superheated steam parameters generated by the waste heat boiler 7 meet the turbine run-up parameters, the intermediate pressure main steam valve 13 and the intermediate pressure regulating steam valve can be opened to directly run the turbine to 3000r / min, and then connected to the grid. After the grid connection, it enters the load increase control, further increases the load of the intermediate pressure regulating steam valve, and gradually closes the low-pressure bypass at the same time. After the low-pressure bypass is fully closed, the load is maintained unchanged and low-load warm-up is performed. After the low-load warm-up is completed, the high-pressure cylinder 4 and the medium-pressure cylinder 3 are switched, that is, the high-pressure regulating valve is opened to allow steam to flow through the high-pressure cylinder 4, and the high-discharge check valve 19 is automatically opened, and the ventilation valve is closed at the same time. After the cylinder switching is completed, the high-bypass hydraulic valve 20 is gradually closed. When the sliding point is reached, the unit starts to slide along with the waste heat boiler 7 to the target load. In this way, the time for the steam turbine to be connected to the grid is greatly saved and the waste of natural gas energy is reduced.

[0045] A skilled person will readily conceive of other embodiments of the invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be regarded as exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0046] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0047] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A molten salt auxiliary system for a gas turbine, characterized in that: It comprises a gas turbine (1), a waste heat boiler (7), a molten salt module (6), a high-pressure main steam valve (11), a high-pressure cylinder (4), a high-exhaust check valve (19), a medium-pressure main steam valve (13), a medium-pressure cylinder (3), a low-pressure main steam valve (15), a molten salt module (6), a high-pressure cylinder reverse warming valve (18) and a medium-pressure cylinder pre-warming valve (17); The outlet of the gas turbine (1) is connected to the flue gas inlet of the waste heat boiler (7) and the heat release side inlet of the molten salt module (6); the main steam outlet of the waste heat boiler (7) is connected to the inlet of the high pressure cylinder (4) via the high pressure main steam valve (11); the outlet of the high pressure cylinder (4) is connected to the reheat side inlet of the waste heat boiler (7) via the high discharge check valve (19); the reheat side outlet of the waste heat boiler (7) is connected to the inlet of the medium pressure cylinder (3) via the medium pressure main steam valve (13); the steam outlet of the medium pressure cylinder (3) is connected to the low pressure steam outlet of the waste heat boiler (7) and the inlet of the low pressure main steam valve (15); the steam outlet of the molten salt module (6) is connected to the steam outlet of the high pressure cylinder (4) via the high pressure cylinder reverse warming valve (18); the steam outlet of the molten salt module (6) is connected to the reheat side outlet of the waste heat boiler (7) via the medium pressure cylinder preheating valve (17).

2. The molten salt auxiliary system for a gas turbine according to claim 1, characterized in that: It also includes an air input pipeline and a natural gas input pipeline, and the air input pipeline and the natural gas input pipeline are connected to the inlet of the gas turbine (1).

3. The molten salt auxiliary system for a gas turbine according to claim 1, characterized in that: It also includes a chimney (10), and the flue gas outlet of the waste heat boiler (7) and the heat release side outlet of the molten salt module (6) are connected to the inlet of the chimney (10).

4. The molten salt auxiliary system for a gas turbine according to claim 1, characterized in that: It also includes a low-pressure cylinder (2), a condenser (9) and a condensate pump (8); the outlet of a low-pressure main steam valve (15) is connected to the inlet of the low-pressure cylinder (2); and the outlet of the low-pressure cylinder (2) is connected to the water inlet of a waste heat boiler (7) via the condenser (9) and the condensate pump (8) in sequence.

5. The molten salt auxiliary system for a gas turbine according to claim 4, characterized in that: The outlet of the condensate pump (8) is connected to the heat absorption side inlet of the molten salt module (6) through the molten salt user water inlet gate (23).

6. The molten salt auxiliary system for a gas turbine according to claim 4, characterized in that: The reheating side outlet of the waste heat boiler (7) is connected to the inlet of the condenser (9) via the middle side hydraulic gate (21).

7. The molten salt auxiliary system for a gas turbine according to claim 4, characterized in that: The inlet of the low-pressure main steam valve (15) is connected to the inlet of the condenser (9) via the low bypass hydraulic valve (22); the main steam outlet of the waste heat boiler (7) is connected to the reheat side inlet of the waste heat boiler (7) via the high bypass hydraulic valve (20).

8. The molten salt auxiliary system for a gas turbine according to claim 4, characterized in that: The molten salt module (6) comprises a hot tank (24), a hot tank outlet door (30), a superheater (29), an evaporator (28), a cold tank (27), a cold tank outlet door (26) and a flue gas-molten salt heat exchanger (25), wherein the outlet of the hot tank (24) is sequentially connected to the inlet of the cold tank (27) via the hot tank outlet door (30), the heat release side of the superheater (29) and the heat release side of the evaporator (28), and the outlet of the cold tank (27) is sequentially connected to the inlet of the hot tank (24) via the cold tank outlet door (26) and the molten salt side of the flue gas-molten salt heat exchanger (25); The flue gas outlet of the gas turbine (1) is connected to the flue gas side inlet of the flue gas-molten salt heat exchanger (25) through the gas turbine exhaust diverter valve (5), and the flue gas side outlet of the flue gas-molten salt heat exchanger (25) is connected to the inlet of the chimney (10); The outlet of the condensate pump (8) is connected to the heat absorption side inlet of the evaporator (28) through the molten salt user water inlet gate (23), the heat absorption side outlet of the evaporator (28) is connected to the heat absorption side inlet of the superheater (29), and the heat absorption side outlet of the superheater (29) is connected to the inlet of the medium-pressure cylinder preheating valve (17) and the high-pressure cylinder (4).

9. The molten salt auxiliary system for a gas turbine according to claim 4, characterized in that: The drain port of the low-pressure cylinder (2) is connected to the inlet of the condenser (9) via a low-pressure cylinder drain valve (16), the drain port of the medium-pressure cylinder (3) is connected to the inlet of the condenser (9) via an medium-pressure cylinder drain valve (14), and the drain port of the high-pressure cylinder (4) is connected to the inlet of the condenser (9) via a high-pressure cylinder drain valve (12).

10. A molten salt auxiliary method for a gas turbine, characterized in that: The following steps are involved: Part of the flue gas discharged by the gas turbine (1) is sent to the molten salt module (6). After the gas turbine (1) is shut down and waiting to be restarted, heat is released through the molten salt module (6) to generate superheated steam, and the superheated steam is used to preheat the steam turbine in advance.

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