A high-parameter industrial steam supply system for cascade utilization and its usage method

Abstract

The present invention discloses a high-parameter industrial steam supply system for cascade utilization and its usage method, comprising: a thermal steam supply system including a deaerator; a high-parameter steam supply system including a main steam supply system and a thermoelectric system; wherein, the main steam supply system includes a variable-frequency booster pump connected in pipeline communication with the outlet of the deaerator, the variable-frequency booster pump is connected in pipeline communication with a first-stage heat exchanger, the outlet of the first heat exchanger is connected in pipeline communication with a second-stage heat exchanger, and the outlet of the second-stage heat exchanger is connected in pipeline communication with a high-pressure industrial steam supply system; the thermoelectric system includes a back-pressure steam turbine, a pipeline is connected between the back-pressure steam turbine and the second-stage heat exchanger for extracting reheat steam from the second-stage heat exchanger to the back-pressure steam turbine, the back-pressure steam turbine is connected with a power generation assembly, and the power generation assembly is electrically connected with the plant power system. The present invention significantly improves the high-parameter industrial steam supply capacity of the unit above 4 MPa by more than double, and expands the cogeneration capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of cogeneration, and particularly relates to a high-parameter industrial steam supply system for cascade utilization and a using method thereof. Background Art

[0002] At present, the country requires to accelerate the development of cogeneration and central heating, implement heating transformation by using existing cogeneration units, pure condensing generator sets and low-grade waste heat around cities and industrial parks, eliminate coal-fired boilers within the heating and gas supply scope, and the self-built boilers of enterprises are greatly restricted. A large number of steam-consuming enterprises have shifted from self-produced steam supply to steam supply by large-scale cogeneration units. However, there is no relatively mature solution for high-parameter industrial steam supply above 4 MPa, such as conventional main steam supply and supplementary steam supply. However, restricted by the reheat over-temperature of the boiler, there are problems of small extraction steam volume. For 600,000-level units, it is generally not more than 100 t / h, and for 300,000-level units, it is only about half of that of 600,000-level units. If facing deep peak shaving, the actual steam supply capacity will further decline, making it difficult to meet the needs of the high-parameter industrial steam supply market and unable to completely replace the self-produced high-parameter industrial steam of steam-consuming enterprises. At the same time, for power production enterprises, there are a large number of electrical equipment inside during the production process. In addition to most of the generated electricity being transmitted to the power grid, a part of the generated electricity must be allocated to maintain the normal operation of the internal power-consuming equipment. Usually, the proportion of this part of internal power consumption is 3-5%, and the proportion will increase for some air-cooled units. Due to the high internal power load of this part of electricity consumption, a large amount of precious electric energy needs to be consumed, resulting in a reduction in the on-grid electricity of the plant available for sale, an increase in the plant electricity rate, and a decline in the operating income.

[0003] The present invention provides an industrial steam supply solution, which can not only realize industrial steam supply with parameters above 4 MPa, but also realize the cascade utilization of steam capacity and reduce the plant electricity rate. Compared with conventional main steam extraction and supplementary steam valve supply, etc., through two-stage heat exchange, the main steam and hot reheat extraction steam are respectively used to heat saturated condensate to the required high-parameter steam in sequence. Summary of the Invention

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

[0005] To achieve the above object, the present invention provides a high-parameter industrial steam supply system for cascade utilization, including:

[0006] A thermal steam supply system, including a deaerator, the outlet of the deaerator is connected to a feed water pump, and the inlet of the deaerator is connected to a low-pressure heater;

[0007] A high-parameter steam supply system, including a main steam supply system and a thermoelectric system;

[0008] Among them, the main steam supply system includes a variable-frequency booster pump connected in series with the outlet of the deaerator through a pipeline. The variable-frequency booster pump is connected in series with a first-stage heat exchanger through a pipeline. The outlet of the first heat exchanger is connected in series with a second-stage heat exchanger through a pipeline. The outlet of the second-stage heat exchanger is connected with the high-pressure industrial steam supply system through a pipeline;

[0009] The thermoelectric system includes a back-pressure steam turbine. The back-pressure steam turbine is connected in series with the second-stage heat exchanger through a pipeline to extract hot re-extracted steam from the second-stage heat exchanger to the back-pressure steam turbine. The back-pressure steam turbine is connected with a power generation component, and the power generation component is electrically connected to the plant power system.

[0010] In the present invention, saturated condensate is led out from the deaerator of the thermal steam supply system, and the saturated condensate is subjected to multi-stage heat exchange treatment through the first-stage heat exchanger and the second-stage heat exchanger, so that the original thermal steam supply system doubles or more its ability to supply steam to a high-parameter industrial steam supply system above 4 MPa, and the hot re-extracted steam is used for power generation, realizing the multi-stage utilization of steam and expanding the cogeneration capacity.

[0011] Optionally, the thermal steam supply system further includes a boiler, a low-pressure cylinder, a medium-pressure cylinder, and a high-pressure cylinder. The boiler is connected with the high-pressure cylinder through a main steam pipeline, and the boiler is connected with the medium-pressure cylinder through a hot re-extracted steam pipeline. The first-stage heat exchanger is connected with the main steam pipeline, and the second-stage heat exchanger is connected with the hot re-extracted steam pipeline.

[0012] Further, a first valve group and a second valve group for controlling the on-off and flow rate of the corresponding pipelines are respectively arranged on the main steam pipeline and the hot re-extracted steam pipeline.

[0013] Further, a steam recovery pipeline is arranged between the medium-pressure cylinder and the low-pressure cylinder. The back-pressure steam turbine is connected with the steam recovery pipeline through a branch recovery pipeline, and a third valve group is arranged at the inlet of the low-pressure cylinder on the steam recovery pipeline.

[0014] Further, a first control valve is arranged at the inlet pipeline of the variable-frequency booster pump, a second control valve is arranged at the outlet pipeline of the second-stage heat exchanger, a third control valve is arranged on the connecting pipeline between the second-stage heat exchanger and the back-pressure steam turbine, and a fourth control valve is arranged on the branch recovery pipeline.

[0015] Further, the first-stage heat exchanger is provided with a condensate return circuit, and the condensate return circuit is connected with the inlet of the deaerator to enable the main steam condensate in the first-stage heat exchanger to flow back to the deaerator, and a fifth control valve is arranged on the condensate return circuit.

[0016] Further, the connecting pipe between the second-stage heat exchanger and the back-pressure steam turbine is a cooling pipe, so that the internal heat extraction steam in the second-stage heat exchanger is cooled and then enters the back-pressure steam turbine, and a fourth valve group is arranged at one end of the cooling pipe close to the low-pressure cylinder.

[0017] Further, the power generation assembly includes a gearbox drivingly connected to the back-pressure steam turbine, and an output shaft of the gearbox is connected with an asynchronous generator set to drive the asynchronous generator set to perform power generation operations, and the asynchronous generator set is electrically connected to the plant power system.

[0018] A method for using a high-parameter industrial steam supply system for cascade utilization includes the following steps:

[0019] S1. Control the frequency conversion booster pump to work, extract saturated condensate from the deaerator, and pressurize the saturated condensate for supply to the first-stage heat exchanger.

[0020] S2. The main steam is extracted along the main steam pipe into the first-stage heat exchanger to perform a heat exchange operation with the saturated condensate, and saturated steam is generated in the first-stage heat exchanger for supply to the second-stage heat exchanger.

[0021] S3. The internal heat extraction steam passes through the internal heat extraction steam pipe into the second-stage heat exchanger, and performs a heat exchange operation with the saturated hot steam in the second-stage heat exchanger to reheat the saturated hot steam.

[0022] S4. The saturated hot steam heated in S3 enters the high-pressure industrial steam supply system, and the internal heat extraction steam in the second-stage heat exchanger enters the back-pressure steam turbine through the cooling pipe to drive it to work, driving the power generation assembly to perform power generation operations for power supplementary supply to the plant power system.

[0023] Further, in S2, after the main steam exchanges heat with the saturated condensate in the first-stage heat exchanger, it forms condensate, which flows back to the inlet of the deaerator through the condensate return circuit. After being processed by the deaerator to become saturated condensate, under the action of the frequency conversion booster pump, the saturated condensate flows through the pipeline again into the frequency conversion high-pressure pump to perform step S1.

[0024] Further, in S4, the internal heat extraction steam from the second-stage heat exchanger entering the back-pressure steam turbine drives the back-pressure steam turbine to work and then flows back into the low-pressure cylinder along the branch recovery pipeline.

[0025] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, in which:

[0027] Figure 1 FIG. 4 is a schematic structural diagram of a high-parameter industrial steam supply system for cascade utilization according to the present invention;

[0028] Figure 2 FIG. 8 is a schematic flow diagram of a method for using a high-parameter industrial steam supply system for cascade utilization according to the present invention.

[0029] Description of the reference numerals:

[0030] 1. Boiler; 2. High-pressure cylinder; 3. Intermediate-pressure cylinder; 4. Low-pressure cylinder; 5. High-pressure heater; 6. Deaerator; 7. Feed water pump; 8. Low-pressure heater; 9. Condensate pump; 10. Condenser; 11. Third valve group; 12. First control valve; 13. First valve group; 14. Fifth control valve; 15. Second valve group; 16. Fourth control valve; 17. Variable-frequency booster pump; 18. First-stage heat exchanger; 19. Second-stage heat exchanger; 20. Back-pressure steam turbine; 21. Gearbox and coupling; 22. Asynchronous generator set; 23. Third control valve; 24. Second control valve; 25. Fourth valve group; 26. Plant power system. Detailed embodiments

[0031] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0032] The present invention discloses a high-parameter industrial steam supply system for cascade utilization, which will be elaborated in detail below with reference to Figure 1 for detailed elaboration

[0033] A high-parameter industrial steam supply system for cascade utilization includes a thermal steam supply system and a multi-stage utilization system for thermal steam supply:

[0034] The thermal steam supply system includes a deaerator 6. The outlet of the deaerator 6 is connected to a feed water pump 7, and the inlet of the deaerator 6 is connected to a low-pressure heater 8.

[0035] The high-parameter steam supply system includes a main steam supply system and a thermoelectric system;

[0036] Among them, the main steam supply system includes a variable-frequency booster pump 17 connected to the outlet of the deaerator 6 through a pipeline. The variable-frequency booster pump 17 is connected to a first-stage heat exchanger 18 through a pipeline. The pipeline at the outlet of the first heat exchanger is connected to a second-stage heat exchanger 19. The outlet of the second-stage heat exchanger 19 is connected to the high-pressure industrial steam supply system through a pipeline;

[0037] The thermoelectric system includes a back-pressure steam turbine 20. There is a pipeline connection between the back-pressure steam turbine 20 and the second-stage heat exchanger 19 to draw hot re-extracted steam from the second-stage heat exchanger 19 into the back-pressure steam turbine 20. The back-pressure steam turbine 20 is connected to a power generation assembly, and the power generation assembly is electrically connected to the plant power system 26.

[0038] In the present invention, saturated condensed water is led out from the deaerator 6 of the thermal steam supply system, and through the first-stage heat exchanger 18 and the second-stage heat exchanger 19, the saturated condensed water is subjected to multi-stage heat exchange treatment, so that the original thermal steam supply system's ability to supply steam to a high-parameter industrial steam supply system above 4 MPa is increased by more than one time, and the hot re-extracted steam is used for power generation, realizing the multi-stage utilization of steam, expanding the cogeneration capacity, and avoiding the throttling loss caused by direct desuperheating and pressure reduction of industrial steam, thus improving the energy utilization efficiency.

[0039] Among them, the thermal steam supply system further includes a boiler 1, a low-pressure cylinder 4, an intermediate-pressure cylinder 3, and a high-pressure cylinder 2. There is a main steam pipeline connecting the boiler 1 and the high-pressure cylinder 2, and a hot re-extracted steam pipeline connecting the boiler 1 and the intermediate-pressure cylinder 3. The first-stage heat exchanger 18 is connected to the main steam pipeline, and the second-stage heat exchanger 19 is connected to the hot re-extracted steam pipeline. First valve groups 13 and second valve groups 15 for controlling the on / off and flow rate of the corresponding pipelines are respectively arranged on the main steam pipeline and the hot re-extracted steam pipeline.

[0040] And in the thermal steam supply system, there is a pipeline connection between the intermediate-pressure cylinder 3 and the boiler 1. The outlet of the low-pressure cylinder 4 is connected to a condenser through a pipeline. The low-pressure steam in the low-pressure cylinder 4 is condensed into condensed water by the condenser. The outlet of the condenser is connected to a low-pressure heater 8 through a pipeline, and a condensate pump 9 is arranged on the pipeline between the condenser and the low-pressure heater 8. The condensed water condensed by the condenser is supplied to the low-pressure heater 8 for heating treatment through the condensate pump 9. The outlet of the low-pressure heater 8 is connected to the deaerator 6 through a pipeline. After being heated by the low-pressure heater 8, the condensed water flows to the deaerator 6 for processing. The outlet of the deaerator 6 is connected to the boiler 1 through a pipeline, and a feed water pump 7 and a high-pressure heater 5 are arranged on this section of the pipeline, which are used to supply the saturated condensed water processed by the deaerator 6 to the boiler 1. That is, a part of the saturated condensed water processed by the deaerator 6 is supplied to the boiler 1, and the other part is diverted into the variable-frequency booster pump 17.

[0041] Among them, a steam recovery pipeline is arranged between the intermediate-pressure cylinder 3 and the low-pressure cylinder 4; further considering that when hot re-extracted steam is generated in the high-parameter steam supply system and enters the back-pressure steam turbine to do work, it is also necessary to recover this steam. Therefore, a branch recovery pipeline is connected between the back-pressure steam turbine 20 and the steam recovery pipeline. A third valve group 11 is arranged at the inlet of the low-pressure cylinder 4 of the steam recovery pipeline. And in this embodiment, this valve group is set as a butterfly valve. It is used to introduce the steam in the back-pressure steam turbine 20 into the low-pressure cylinder 4 for synchronous recovery and reuse. And in the thermoelectric system, the pipeline connecting the second-stage heat exchanger 19 and the back-pressure steam turbine 20 is a cooling pipeline. By allowing the steam to cool naturally during pipeline transportation, the hot re-extracted steam in the second-stage heat exchanger 19 is cooled and then enters the back-pressure steam turbine 20. And a fourth valve group 25 is arranged at one end of the cooling pipeline close to the low-pressure cylinder 4.

[0042] Further, in the thermoelectric system, the power generation assembly includes a gearbox that is drivingly connected to the back-pressure steam turbine 20. The output shaft of the gearbox is connected to an asynchronous generator set 22, which is used to drive the asynchronous generator set 22 to perform power generation operations. The step generator set is electrically connected to the plant power system 26.

[0043] In order to control the steam flow rate and on-off of each pipeline in a targeted manner, a first control valve 12 is arranged at the inlet pipeline of the variable-frequency booster pump 17, a second control valve 24 is arranged at the outlet pipeline of the second-stage heat exchanger 19, a third control valve 23 is arranged on the pipeline connecting the second-stage heat exchanger 19 and the back-pressure steam turbine 20, and a fourth control valve 16 is arranged on the branch recovery pipeline.

[0044] Further, considering that after the steam in the main steam pipeline exchanges heat with the condensed water entering the first-stage heat exchanger 18, the temperature of the main steam decreases and condensed water is generated. The condensed water generated by the main steam in the first-stage heat exchanger 18 needs to be recovered and reused. Therefore, a condensate return circuit is arranged in the first-stage heat exchanger 18. The condensate return circuit is connected to the inlet of the deaerator 6, so that the main steam condensate in the first-stage heat exchanger 18 flows back to the deaerator 6. A fifth control valve 14 is arranged on the condensate return circuit.

[0045] The working principle of the present invention is as follows:

[0046] The main steam at the outlet of the boiler 1 is divided into two paths. One path enters the first-stage heat exchanger 18 through the main steam pipeline, and the other path enters the high-pressure cylinder 2 through the main steam pipeline to do work. The exhaust steam of the high-pressure cylinder 2 enters the boiler 1 again through the pipeline for secondary heating as reheated steam;

[0047] The reheated steam at the outlet of the boiler 1 is divided into two paths. One path enters the hot-side fluid inlet of the second-stage heat exchanger 19 through the hot re-extraction pipeline, and the second path enters the intermediate-pressure cylinder 3 through the pipeline to do work;

[0048] The exhaust steam of the medium-pressure cylinder 3 enters the low-pressure cylinder 4 through the recovery pipeline to do work. After the steam does work in the low-pressure cylinder 4, it successively passes through the condenser 10 to form condensate, and under the action of the condensate pump 9, it reaches the deaerator 6 through the low-pressure heater 8, and saturated condensate is formed after the operation of the deaerator 6;

[0049] The saturated condensate is divided into two paths at the outlet of the deaerator 6. One path enters the boiler 1 to do work to generate main steam, and the other path is pressurized by the variable-frequency booster pump 17 and then supplied to the first-stage heat exchanger 18;

[0050] In the first-stage heat exchanger 18, the main steam exchanges heat with the saturated condensate to generate saturated steam and main steam condensate. The main steam condensate flows out from the hot-side fluid outlet of the first-stage heat exchanger 18 and re-enters the deaerator 6 through the condensate water circuit. The saturated steam enters the second-stage heat exchanger 19 through the cold-side fluid outlet of the first-stage heat exchanger 18. In the second-stage heat exchanger, the saturated steam exchanges heat with the hot re-extracted steam entering the second-stage heat exchanger 19. The superheated steam at the cold-side fluid outlet of the second-stage heat exchanger 19 after heat exchange is supplied to the high-parameter industrial steam supply system. The steam at the hot-side fluid outlet of the second-stage heat exchanger 19 enters the back-pressure steam turbine 20 through the cooling pipeline, drives the back-pressure steam turbine 20 to do work, and thus drives the power generation component to perform power generation operations. The power generated by the power generation operations is supplied to the plant power system 26;

[0051] After the steam does work in the back-pressure steam turbine 20, it enters the low-pressure cylinder 4 through the branch recovery pipeline to do work. After the steam completes the work in the low-pressure cylinder 4, it will enter the condenser 10 again to form condensate, and under the action of the condensate pump 9, it reaches the deaerator 6 through the low-pressure heater 8, forming a thermal cycle.

[0052] The present invention also provides a method for using a high-parameter industrial steam supply system for cascade utilization, which is described in detail below with reference to Figure 2 for elaboration.

[0053] A method for using a high-parameter industrial steam supply system for cascade utilization includes the following steps:

[0054] S1. Control the variable-frequency booster pump 17 to work, extract saturated condensate from the deaerator 6, and pressurize the saturated condensate, and supply it to the first-stage heat exchanger 18;

[0055] S2. The main steam is extracted along the main steam pipeline into the first-stage heat exchanger 18 to perform heat exchange operations with the saturated condensate, and saturated steam is generated in the first-stage heat exchanger 18 to be supplied to the second-stage heat exchanger 19;

[0056] S3. The hot re-extracted steam enters the second-stage heat exchanger 19 through the hot re-extracted steam pipeline, and performs heat exchange operations with the saturated hot steam in the second-stage heat exchanger 19 to reheat the saturated hot steam;

[0057] S4. The saturated hot steam heated in S3 enters the high-pressure industrial gas supply system, and the internal re-extracted steam in the second-stage heat exchanger 19 enters the back-pressure steam turbine 20 through the cooling pipeline to drive it to work, driving the power generation assembly to perform power generation operations for power supplementary supply to the plant power system 26.

[0058] Among them, in S2, after the main steam exchanges heat with the saturated condensed water in the first-stage heat exchanger 18, it forms condensed water, which flows back to the inlet of the deaerator 6 through the condensed water circuit. After being treated by the deaerator 6 to become saturated condensed water, under the action of the variable-frequency booster pump 17, the saturated condensed water flows through the pipeline again to the variable-frequency high-pressure pump for step S1.

[0059] Among them, in S4, the internal re-extracted steam from the second-stage heat exchanger 19 entering the back-pressure steam turbine 20 drives the back-pressure steam turbine 20 to work and then flows back into the low-pressure cylinder 4 along the branch recovery pipeline.

[0060] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0061] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0062] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A high-parameter industrial steam supply system for cascade utilization, characterized in that, Including: A thermal steam supply system including a deaerator. The outlet of the deaerator is connected to a feed water pump, and the inlet of the deaerator is connected to a low-pressure heater; A high-parameter steam supply system including a main steam supply system and a thermoelectric system; Wherein, the main steam supply system includes a variable-frequency booster pump connected in series with the outlet of the deaerator through a pipeline. The variable-frequency booster pump is connected to a first-stage heat exchanger through a pipeline. The outlet of the first-stage heat exchanger is connected to a second-stage heat exchanger through a pipeline. The outlet of the second-stage heat exchanger is connected to a high-pressure industrial steam supply system through a pipeline; The thermoelectric system includes a back-pressure steam turbine. A pipeline is connected between the back-pressure steam turbine and the second-stage heat exchanger to extract hot re-extracted steam from the second-stage heat exchanger into the back-pressure steam turbine. The back-pressure steam turbine is connected to a power generation assembly, and the power generation assembly is electrically connected to the plant power system; The thermal steam supply system further includes a boiler, a low-pressure cylinder, an intermediate-pressure cylinder, and a high-pressure cylinder. A main steam pipeline is connected between the boiler and the high-pressure cylinder, and a hot re-extracted steam pipeline is connected between the boiler and the intermediate-pressure cylinder. The first-stage heat exchanger is connected to the main steam pipeline, and the second-stage heat exchanger is connected to the hot re-extracted steam pipeline; A steam recovery pipeline is provided between the intermediate-pressure cylinder and the low-pressure cylinder. A branch recovery pipeline is connected between the back-pressure steam turbine and the steam recovery pipeline. A third valve group is provided at the inlet of the low-pressure cylinder where the steam recovery pipeline is located; The first-stage heat exchanger is provided with a condensate water circuit, and the condensate water circuit is connected to the inlet of the deaerator so that the main steam condensate in the first-stage heat exchanger flows back to the deaerator. A fifth control valve is provided on the condensate water circuit; 2. The high-parameter industrial steam supply system for cascade utilization according to claim 1, wherein A first valve group and a second valve group for controlling the on / off and flow rate of the corresponding pipelines are respectively provided on the main steam pipeline and the hot re-extracted steam pipeline; 3. The high-parameter industrial steam supply system for cascade utilization according to claim 1, characterized in that, A first control valve is provided at the inlet pipeline of the variable-frequency booster pump, a second control valve is provided at the outlet pipeline of the second-stage heat exchanger, a third control valve is provided on the pipeline connecting the second-stage heat exchanger and the back-pressure steam turbine, and a fourth control valve is provided on the branch recovery pipeline; 4. The high-parameter industrial steam supply system for cascade utilization according to claim 1, characterized in that, The pipeline connecting the second-stage heat exchanger and the back-pressure steam turbine is a cooling pipeline so that the hot re-extracted steam in the second-stage heat exchanger is cooled and then enters the back-pressure steam turbine. A fourth valve group is provided at one end of the cooling pipeline close to the low-pressure cylinder; 5. The high-parameter industrial steam supply system for cascade utilization according to claim 1, characterized in that, The power generation assembly includes a gearbox drivingly connected to the back-pressure steam turbine. The output shaft of the gearbox is connected to an asynchronous generator set to drive the asynchronous generator set to perform power generation operations. The asynchronous generator set is electrically connected to the plant power system; 6. A method for using a high-parameter industrial steam supply system for cascade utilization, characterized in that, Using the high-parameter industrial steam supply system for cascade utilization according to any one of claims 1-5, including the following steps: S1. Control the variable-frequency booster pump to operate, extract saturated condensate water from the deaerator, and perform pressurization treatment on the saturated condensate water, and supply it to the first-stage heat exchanger; S2. The main steam is extracted along the main steam pipeline into the first-stage heat exchanger to perform heat exchange operation with the saturated condensate water, and saturated steam is generated in the first-stage heat exchanger to be supplied to the second-stage heat exchanger; S3. The hot re-extracted steam enters the second-stage heat exchanger through the hot re-extracted steam pipeline and exchanges heat with the saturated hot steam in the second-stage heat exchanger to reheate the saturated hot steam again. S4. The saturated hot steam heated in S3 enters the high-pressure industrial gas supply system, and the hot re-extracted steam in the second-stage heat exchanger enters the back-pressure steam turbine through the cooling pipeline to drive it to work, driving the power generation component to perform power generation operations to supplement the power supply of the plant's power system. In S4, the hot re-extracted steam from the second-stage heat exchanger entering the back-pressure steam turbine flows back into the low-pressure cylinder along the branch recovery pipeline after driving the back-pressure steam turbine to work.

7. The usage method of a high-parameter industrial steam supply system for cascade utilization as claimed in claim 6, wherein In S2, after the main steam exchanges heat with the saturated condensed water in the first-stage heat exchanger, it forms condensed water, which flows back to the inlet of the deaerator through the condensed water circuit. After being processed by the deaerator to become saturated condensed water, the saturated condensed water flows through the pipeline again under the action of the variable-frequency booster pump and enters the variable-frequency high-pressure pump for step S1.

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