Electric boiler flexible operation system and method under thermoelectric composite requirement

Abstract

The invention discloses a system and a method for flexible operation of an electric boiler under thermoelectric composite requirements, an outlet of the electric boiler is divided into two paths through an electric boiler steam supply pipeline, one path is communicated with a steam turbine industrial steam extraction pipeline through an electric boiler industrial steam supply valve, and the other path is divided into two paths through an electric boiler steam supply steam turbine rotating pipeline and an electric heater; wherein one path is communicated with a main steam pipeline through an electric boiler high-pressure cylinder steam supply pipeline, the other path is communicated with a reheat steam pipeline through an electric boiler medium-pressure cylinder steam supply pipeline, an outlet of a medium-pressure cylinder is divided into two paths, one path is communicated with an inlet of a low-pressure cylinder, and the other path is communicated with a steam turbine industrial steam extraction pipeline through a steam turbine industrial steam extraction valve. According to the system and method, when the peak load regulation load of the steam turbine is low or the steam turbine is shut down during peak regulation, the industrial steam extraction flow meets the user requirement, and meanwhile, the unit can consider two-shift peak regulation and industrial steam extraction parameters.

Description

Technical Field

[0001] The present invention belongs to the field of flexible operation of thermal power units under peak load regulation-heating conditions, and relates to a system and method for flexible operation of electric boilers under thermal power composite demand. Background Art

[0002] At present, with the annual increase in installed capacity of new energy, thermal power generation has become the ballast stone to ensure the stability of the power grid, so higher requirements are placed on the operational flexibility of thermal power units. In terms of peak-shaving operation, especially for the two-shift peak-shaving operation of thermal power units, the start-up and shutdown costs of the units are high, and the expansion difference of the steam turbine and the temperature difference between the upper and lower cylinders are difficult to control. In terms of industrial heating / steam, when the peak-shaving load of the steam turbine is low or the peak-shaving shutdown is in place, the industrial steam extraction flow cannot meet user needs. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and to provide a system and method for flexible operation of electric boilers under thermal power combined demand. The system and method can ensure that the industrial steam extraction flow meets user needs when the turbine peak load is low or the turbine is shut down for peak load regulation, and at the same time, the unit can take into account two-shift peak load regulation and industrial steam extraction parameters.

[0004] To achieve the above-mentioned purpose, the present invention discloses a flexible operation system of an electric boiler under the demand of heat and power combination, including a water supply pipeline from feed water to the electric boiler, a water supply pipeline from desalted water to the electric boiler, an electric boiler, a steam supply pipeline of the electric boiler, an industrial steam valve for the electric boiler, an industrial steam extraction pipeline of a steam turbine, a steam pipeline for the electric boiler to rotate the steam turbine, an electric heater, a main steam pipeline, a reheat steam pipeline, a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder;

[0005] The outlet of the water supply pipeline from the feed water to the electric boiler and the water supply pipeline from the desalted water to the electric boiler are connected to the inlet of the electric boiler. The outlet of the electric boiler is divided into two paths through the steam supply pipeline of the electric boiler, one of which is connected to the industrial steam extraction pipeline of the steam turbine through the industrial steam supply valve of the electric boiler, and the other is divided into two paths after passing through the steam supply pipeline for rotating steam of the steam turbine of the electric boiler and the electric heater, one of which is connected to the main steam pipeline through the steam supply pipeline for the high-pressure cylinder of the electric boiler, and the other is connected to the reheat steam pipeline through the steam supply pipeline for the medium-pressure cylinder of the electric boiler. The outlet of the main steam pipeline is connected to the inlet of the high-pressure cylinder, and the outlet of the reheat steam pipeline is connected to the inlet of the medium-pressure cylinder. The outlet of the medium-pressure cylinder is divided into two paths, one of which is connected to the inlet of the low-pressure cylinder, and the other is connected to the industrial steam extraction pipeline of the steam turbine through the industrial steam extraction valve of the steam turbine;

[0006] The electric boiler steam supply pipeline for supplying steam to the steam turbine is provided with an electric boiler steam supply turbine steam valve, and the electric boiler steam supply pipeline for industrial use is provided with an electric boiler industrial steam supply valve.

[0007] The further improvement of the electric boiler flexible operation system under the heat and power composite demand of the present invention is:

[0008] Furthermore, a desalted water supply valve is provided on the water supply pipeline from the desalted water to the electric boiler.

[0009] Furthermore, a water supply valve is provided on the water supply pipeline from the water supply to the electric boiler.

[0010] Furthermore, a steam supply valve from the electric boiler to the intermediate pressure cylinder is provided on the steam pipeline from the electric boiler to the intermediate pressure cylinder.

[0011] Furthermore, a steam supply valve from the electric boiler to the high-pressure cylinder is provided on the steam pipeline from the electric boiler to the high-pressure cylinder.

[0012] Furthermore, the high-pressure cylinder, the medium-pressure cylinder, the low-pressure cylinder and the generator are coaxially arranged, and the output end of the generator is connected to the power interface of the electric boiler.

[0013] The method for flexible operation of electric boilers under heat and power composite demand described in the present invention includes normal operation, deep peak regulation and two-shift start-stop peak regulation.

[0014] The further improvement of the method for flexible operation of electric boilers under heat and power composite demand of the present invention is:

[0015] Furthermore, under normal operation, the main steam and reheated steam from the boiler enter the high-pressure cylinder and the medium-pressure cylinder respectively through the main steam pipe and the reheated steam pipe to perform work, and industrial steam is provided to industrial steam users by opening the industrial steam extraction valve of the steam turbine.

[0016] Furthermore, under deep peak regulation, the electric boiler is started. The power supply of the electric boiler is taken from the export bus of the generator, and the water source of the electric boiler comes from the unit feed water pump. Water is supplied to the electric boiler by opening the feed water supply valve. The feed water is heated by the electric boiler to become steam, and then industrial steam is provided to industrial steam users through the electric boiler industrial steam pipeline.

[0017] Furthermore, under the two-shift start-stop peak-shaving system, the electricity consumed by the electric boiler is taken from the power grid via the generator outlet bus, and the water supply to the electric boiler comes from the desalted water to the electric boiler water supply pipeline. The desalted water is heated to achieve superheated steam parameters matching those of industrial extraction steam. The electric boiler's industrial steam supply valve and the electric boiler's steam turbine supply valve are opened respectively to supply steam to industrial steam users and the steam turbine respectively. Since there is a gap between the steam parameters of industrial extraction steam and the steam parameters of the turbine rotor and cylinder, the electric heater is turned on to reheat the steam at the outlet of the electric boiler to match its parameters with the turbine rotor and cylinder temperature parameters. Then the electric boiler to high-pressure cylinder steam supply valve and the electric boiler to medium-pressure cylinder steam supply valve are opened to allow steam to enter the turbine.

[0018] The present invention has the following beneficial effects:

[0019] The electric boiler flexible operation system and method under the combined heat and power demand described in the present invention, during specific operation, can, with the help of the characteristics of the electric boiler, not only provide industrial users with industrial extraction steam with stable parameters, but also provide the steam turbine with unit hot rotary steam when the unit has a low peak load or is shut down for peak load regulation. This enables the unit to take into account both two-shift peak load regulation and industrial extraction steam parameters, greatly improving the unit's operating flexibility and enhancing the operating efficiency of the power generation company under the background of combined heat and power demand.

[0020] Furthermore, since the water supply of the electric boiler comes from the outlet of the feed water pump, the outlet feed water of the feed water pump has a relatively high temperature. Therefore, when the feed water is heated to parameters matching those of industrial steam, the power consumption of the electric boiler is relatively small. Under this operating condition, the steam demand of industrial users is guaranteed, and the deep adjustment capability of the unit can be relatively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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:

[0022] Figure 1 It is a structural diagram of the present invention.

[0023] Among them, 1 is the electric boiler, 2 is the electric heater, 3 is the electric boiler steam supply pipeline, 4 is the electric boiler steam supply pipeline for turbine rotation, 5 is the electric boiler steam supply pipeline for industrial use, 6 is the steam extraction pipeline for steam turbine, 7 is the electric boiler steam supply pipeline for high-pressure cylinder, 8 is the electric boiler steam supply pipeline for medium-pressure cylinder, 9 is the main steam pipeline, 10 is the reheat steam pipeline, 11 is the feed water to electric boiler water supply pipeline, 12 is the desalted water to electric boiler water supply pipeline, 13 is the electric boiler industrial steam valve, 14 is the electric boiler steam valve for steam turbine, 15 is the steam extraction valve for steam turbine, 16 is the electric boiler to medium-pressure cylinder steam supply valve, 17 is the electric boiler to high-pressure cylinder steam supply valve, 18 is the desalted water supply valve, and 19 is the feed water supply valve. DETAILED DESCRIPTION

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] Embodiment 1

[0033] The electric boiler flexible operation system under the heat and power composite demand described in the present invention comprises a water supply pipeline 11 from feed water to the electric boiler, a water supply pipeline 12 from desalted water to the electric boiler, an electric boiler 1, an electric boiler steam supply pipeline 3, an electric boiler industrial steam valve 13, a steam turbine industrial extraction pipeline 6, an electric boiler steam supply pipeline 4 for turbine rotation, an electric heater 2, a main steam pipeline 9, a reheat steam pipeline 10, a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder; the outlet of the water supply pipeline 11 from feed water to the electric boiler and the water supply pipeline 12 from desalted water to the electric boiler are connected to the inlet of the electric boiler 1, and the outlet of the electric boiler 1 is divided into two paths through the electric boiler steam supply pipeline 3, one of which is connected to the electric boiler The industrial steam supply valve 13 is connected to the industrial steam extraction pipeline 6 of the steam turbine, and the other route is divided into two routes after passing through the electric boiler steam supply turbine rotation steam pipeline 4 and the electric heater 2. One route is connected to the main steam pipeline 9 through the electric boiler steam supply high-pressure cylinder steam pipeline 7, and the other route is connected to the reheat steam pipeline 10 through the electric boiler steam supply medium-pressure cylinder steam pipeline 8. The outlet of the main steam pipeline 9 is connected to the inlet of the high-pressure cylinder, and the outlet of the reheat steam pipeline 10 is connected to the inlet of the medium-pressure cylinder. The outlet of the medium-pressure cylinder is divided into two routes, one of which is connected to the inlet of the low-pressure cylinder, and the other route is connected to the industrial steam extraction pipeline 6 of the steam turbine through the steam turbine industrial steam extraction valve 15.

[0034] As an embodiment of the present invention, a steam valve 14 for supplying steam to the steam turbine from an electric boiler is provided on the steam pipe 4 for supplying steam to the steam turbine from an electric boiler.

[0035] As an embodiment of the present invention, an electric boiler industrial steam valve 13 is provided on the electric boiler industrial steam pipeline 5 .

[0036] The flexible operation method of the electric boiler under the heat and power composite demand described in the present invention includes normal operation, deep peak regulation and two-shift start-stop peak regulation.

[0037] As an embodiment of the present invention, under normal operation, the main steam and reheated steam from the boiler enter the high-pressure cylinder and the medium-pressure cylinder respectively through the main steam pipe 9 and the reheated steam pipe 10 to perform work, and industrial steam is provided to industrial steam users by opening the steam turbine industrial steam extraction valve 15.

[0038] As an embodiment of the present invention, under deep peak regulation, the electric boiler 1 is started, the power supply of the electric boiler 1 is taken from the outlet bus of the generator, the water source of the electric boiler 1 comes from the unit feed water pump, and water is supplied to the electric boiler 1 by opening the feed water supply valve 19. The feed water is heated by the electric boiler 1 to become steam, and then industrial steam is provided to industrial steam users through the electric boiler industrial steam supply pipeline 5.

[0039] As an embodiment of the present invention, under the two-shift start-stop peak regulation, the electricity consumption of the electric boiler 1 is taken from the power grid through the generator outlet bus, and the water supply of the electric boiler 1 comes from the desalted water to the electric boiler water supply pipeline 12. The desalted water is heated to achieve superheated steam parameters matching the industrial extraction steam, and the electric boiler industrial steam supply valve 13 and the electric boiler steam supply valve 14 are opened respectively to supply steam to industrial steam users and the steam turbine respectively. Since there is a gap between the steam parameters of the industrial extraction steam and the steam parameters of the turbine rotor and cylinder, the electric heater 2 is turned on to reheat the steam at the outlet of the electric boiler 1 to make its parameters match the temperature parameters of the turbine rotor and cylinder, and then the electric boiler to the high-pressure cylinder steam supply valve 17 and the electric boiler to the medium-pressure cylinder steam supply valve 16 are opened to allow the steam to enter the turbine.

[0040] Embodiment 2

[0041] The electric boiler flexible operation system under the heat and power composite demand of the present invention comprises an electric boiler 1, an electric heater 2, an electric boiler steam supply pipeline 3, an electric boiler steam supply pipeline 4 for steam turbine rotation, an electric boiler steam supply pipeline 5 for industrial use, a steam extraction pipeline 6 for steam turbine, an electric boiler steam supply pipeline 7 for high-pressure cylinders, an electric boiler steam supply pipeline 8 for medium-pressure cylinders, a main steam pipeline 9, a reheat steam pipeline 10, a water supply pipeline 11 to the electric boiler, a water supply pipeline 12 to the electric boiler from desalted water, an industrial steam supply valve 13 to the electric boiler, a steam supply valve 14 to the steam turbine from the electric boiler, an industrial steam extraction valve 15 to the steam turbine, a steam supply valve 16 to the medium-pressure cylinder from the electric boiler, a steam supply valve 17 to the high-pressure cylinder from the electric boiler, a desalted water supply valve 18 and a water supply valve 19;

[0042] A desalted water supply valve 18 is provided on the desalted water to electric boiler water supply pipeline 12; a feed water valve 19 is provided on the water supply to electric boiler water supply pipeline 11; the outlet of the water supply to electric boiler water supply pipeline 11 and the desalted water to electric boiler water supply pipeline 12 are connected with the inlet of the electric boiler 1; the outlet of the electric boiler 1 is divided into two paths through the electric boiler steam supply pipeline 3, one of which is connected with the steam turbine industrial steam extraction pipeline 6 through the electric boiler industrial steam supply valve 13, and the other is connected with the steam turbine rotation steam pipeline 4 and the electric boiler through the electric boiler steam supply pipeline 4. After the heater 2, it is divided into two paths, one of which is connected to the main steam pipeline 9 through the electric boiler to supply the high-pressure cylinder steam pipeline 7, and the other is connected to the reheat steam pipeline 10 through the electric boiler to supply the medium-pressure cylinder steam pipeline 8. The outlet of the main steam pipeline 9 is connected to the inlet of the high-pressure cylinder, and the outlet of the reheat steam pipeline 10 is connected to the inlet of the medium-pressure cylinder. The outlet of the medium-pressure cylinder is divided into two paths, one of which is connected to the inlet of the low-pressure cylinder, and the other is connected to the industrial steam extraction pipeline 6 of the turbine through the steam turbine to supply the industrial steam extraction valve 15.

[0043] As an embodiment of the present invention, an electric boiler steam supply valve 14 is provided on the electric boiler steam supply pipeline 4 for turbine rotation; an electric boiler to medium-pressure cylinder steam supply valve 16 is provided on the electric boiler steam supply pipeline 8 for medium-pressure cylinder; an electric boiler to high-pressure cylinder steam supply valve 17 is provided on the electric boiler steam supply pipeline 7 for high-pressure cylinder; and an electric boiler to industrial steam supply valve 13 is provided on the electric boiler industrial steam supply pipeline 5.

[0044] As an implementation mode of the present invention, the high-pressure cylinder, the medium-pressure cylinder, the low-pressure cylinder and the generator are coaxially arranged, and the output end of the generator is connected to the power interface of the electric boiler 1.

[0045] The operation of the present invention is divided into three working conditions, namely normal operation, deep peak regulation, and two-shift start-stop peak regulation.

[0046] 1. Normal operation

[0047] When the unit operates normally, the main steam and reheated steam from the boiler enter the high-pressure cylinder and the medium-pressure cylinder respectively through the main steam pipe 9 and the reheated steam pipe 10 to perform work, and industrial steam is provided to industrial steam users by opening the steam turbine industrial steam extraction valve 15.

[0048] 2. Deep peak load operation

[0049] When the unit is in deep peak-shaving operation, as the unit load decreases, the steam parameters provided by the unit to industrial steam users cannot meet the normal use requirements of users. At this time, the electric boiler 1 is started, and the power supply of the electric boiler 1 is taken from the outlet bus of the generator. The water source of the electric boiler 1 comes from the unit feed water pump. By opening the feed water supply valve 19, the water is supplied to the electric boiler 1. The feed water is heated by the electric boiler 1 to become steam, and then the industrial steam is provided to the industrial steam users through the electric boiler industrial steam supply pipeline 5. Since the electricity used by the electric boiler 1 is taken from the outlet of the generator, the amount of electricity connected to the grid by the generator is reduced, and the peak-shaving depth of the thermal power unit is relatively improved. In addition, since the water supply of the electric boiler 1 comes from the outlet of the feed water pump, the outlet feed water of the feed water pump has a relatively high temperature. Therefore, when the feed water is heated to the parameters matching the industrial steam, the power consumption of the electric boiler 1 is relatively small. Under this condition, the steam demand of industrial users is guaranteed, and the deep regulation capability of the unit can be relatively improved.

[0050] 3. Two-shift start-stop peak load regulation

[0051] When the thermal power unit is started and stopped in two shifts for peak load regulation, after the unit is shut down, the cooling speed of the turbine rotor is relatively fast compared with the cooling speed of the cylinder, and the upper half of the cylinder is faster than the lower half, so the industrial steam extraction is interrupted. Therefore, in order to ensure the safe operation of the unit when it is restarted, slow down the cooling speed of the rotor and the upper half of the cylinder, and provide uninterrupted industrial steam supply when the unit is shut down, the electric boiler 1 is used to provide superheated steam. At this time, the electricity used by the electric boiler 1 is taken from the power grid through the generator outlet bus. The water supply of the electric boiler 1 comes from the desalted water to the electric boiler water supply pipeline 12. By heating the desalted water to achieve the superheated steam parameters that match the industrial steam extraction, the electric boiler industrial steam valve 13 and the electric boiler steam turbine steam valve 14 are opened respectively to supply steam to industrial steam users and steam turbines respectively. Since there is a certain gap between the parameters of industrial extraction steam and the steam parameters of the turbine rotor and cylinder, the electric heater 2 is turned on to reheat the steam at the outlet of the electric boiler 1 to make its parameters match the temperature parameters of the turbine rotor and cylinder, and then the steam supply valve 17 from the electric boiler to the high-pressure cylinder and the steam supply valve 16 from the electric boiler to the medium-pressure cylinder are opened to allow steam to enter the turbine to maintain a low temperature drop rate for the rotor and cylinder.

[0052] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present 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 considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0053] 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.

[0054] 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 flexible operation system for electric boilers under heat and power composite demand, characterized in that: It includes a water supply pipeline from feed water to electric boiler (11), a water supply pipeline from desalted water to electric boiler (12), an electric boiler (1), a steam supply pipeline from electric boiler (3), an industrial steam valve for electric boiler (13), an industrial steam extraction pipeline for steam turbine (6), a steam pipeline for electric boiler to supply steam for turbine rotation (4), an electric heater (2), a main steam pipeline (9), a reheat steam pipeline (10), a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder; The outlet of the feed water to electric boiler water supply pipeline (11) and the desalted water to electric boiler water supply pipeline (12) are connected to the inlet of the electric boiler (1). The outlet of the electric boiler (1) is divided into two paths through the electric boiler steam supply pipeline (3), one of which is connected to the industrial steam extraction pipeline (6) of the steam turbine through the electric boiler industrial steam supply valve (13), and the other is divided into two paths after passing through the electric boiler steam supply pipeline (4) for rotating steam for the steam turbine and the electric heater (2). One of which is connected to the main steam pipeline (9) through the electric boiler steam supply pipeline for high-pressure cylinder (7), and the other is connected to the reheat steam pipeline (10) through the electric boiler steam supply pipeline for medium-pressure cylinder (8). The outlet of the main steam pipeline (9) is connected to the inlet of the high-pressure cylinder, and the outlet of the reheat steam pipeline (10) is connected to the inlet of the medium-pressure cylinder. The outlet of the medium-pressure cylinder is divided into two paths, one of which is connected to the inlet of the low-pressure cylinder, and the other is connected to the industrial steam extraction pipeline (6) of the steam turbine through the steam turbine industrial steam extraction valve (15); The electric boiler steam supply pipeline (4) for supplying steam to the steam turbine is provided with an electric boiler steam supply valve (14), and the electric boiler steam supply pipeline (5) for supplying steam to industry is provided with an electric boiler steam supply valve (13).

2. The electric boiler flexible operation system under heat and power composite demand according to claim 1 is characterized in that: A desalted water supply valve (18) is provided on the desalted water to electric boiler water supply pipeline (12).

3. The electric boiler flexible operation system under heat and power composite demand according to claim 1 is characterized in that: A water supply valve (19) is provided on the water supply pipeline (11) for supplying water to the electric boiler.

4. The electric boiler flexible operation system under heat and power composite demand according to claim 1 is characterized in that: The steam pipeline (8) from the electric boiler to the medium-pressure cylinder is provided with a steam supply valve (16) from the electric boiler to the medium-pressure cylinder.

5. The electric boiler flexible operation system under heat and power composite demand according to claim 1 is characterized in that: The electric boiler-to-high-pressure cylinder steam supply pipeline (7) is provided with an electric boiler-to-high-pressure cylinder steam supply valve (17).

6. The electric boiler flexible operation system under heat and power composite demand according to claim 1 is characterized in that: The high-pressure cylinder, the medium-pressure cylinder, the low-pressure cylinder and the generator are coaxially arranged, and the output end of the generator is connected to the power interface of the electric boiler (1).

7. A method for flexibly operating an electric boiler under heat and power composite demand, characterized in that: The electric boiler flexible operation system under the heat and power combined demand described in claim 1 includes normal operation, deep peak regulation and two-shift start and stop peak regulation.

8. The method for flexible operation of electric boilers under heat and power composite demand according to claim 7, characterized in that: Under normal operation, the main steam and reheated steam from the boiler enter the high-pressure cylinder and the medium-pressure cylinder respectively through the main steam pipeline (9) and the reheated steam pipeline (10) to perform work, and industrial steam is provided to industrial steam users by opening the industrial steam extraction valve (15) for the steam turbine.

9. The method for flexible operation of electric boilers under heat and power composite demand according to claim 7, characterized in that: Under deep peak load regulation, the electric boiler (1) is started. The power supply of the electric boiler (1) is taken from the outlet bus of the generator. The water source of the electric boiler (1) comes from the unit feed water pump. Water is supplied to the electric boiler (1) by opening the feed water supply valve (19). The feed water is heated by the electric boiler (1) to become steam, and then industrial steam is provided to industrial steam users through the electric boiler industrial steam supply pipeline (5).

10. The method for flexible operation of electric boilers under heat and power composite demand according to claim 7, characterized in that: In the two-shift start-stop peak load regulation, the electricity used by the electric boiler (1) is taken from the power grid via the generator outlet busbar, and the water supply to the electric boiler (1) comes from the desalted water to the electric boiler water supply pipeline (12). The desalted water is heated to achieve superheated steam parameters matching those of industrial extraction steam, and the electric boiler industrial steam supply valve (13) and the electric boiler steam supply valve (14) are opened to supply steam to industrial steam users and steam turbines respectively. Since the parameters of industrial extraction steam are different from the parameters of steam used by the turbine rotor and cylinder, the electric heater (2) is opened to reheat the steam at the outlet of the electric boiler (1) to match its parameters with the temperature parameters of the turbine rotor and cylinder, and then the electric boiler to high-pressure cylinder steam supply valve (17) and the electric boiler to medium-pressure cylinder steam supply valve (16) are opened to allow steam to enter the turbine.

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