A high-parameter industrial steam supply system and method for combined production of steam and gas

Abstract

The present invention discloses a high-parameter industrial steam supply system and method for combined steam and gas production. The present invention provides an industrial steam supply solution capable of achieving more than 4 MPa. Compared with conventional main steam extraction, supplementary steam valve steam supply and other solutions, through two-stage heat exchange, the main steam and reheated steam are respectively used to heat the saturated condensate to the required high-parameter steam in sequence. First, a booster pump is used to boost the saturated condensate at the outlet of the deaerator to the required pressure, then the main steam heats the high-pressure saturated condensate into saturated steam, and finally the high-temperature reheated steam is used to heat the saturated steam into the required superheated steam for high-pressure steam supply. The reheated steam after temperature reduction drives the back-pressure steam turbine to drive the air compressor to produce compressed air again, which meets the daily use of the power plant and reduces the plant power consumption rate.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial steam supply, and particularly to a high-parameter industrial steam supply system and method for combined steam and gas production. Background Art

[0002] High-temperature and high-pressure steam is one of the raw materials required by the production processes of many industries. In particular, industries such as chemical engineering and petroleum require high-parameter steam above 4 MPa. The conventional solution is for steam-consuming enterprises to build small-scale steam boilers for production by themselves. At present, relevant national and local policies require accelerating the development of cogeneration of heat and power and centralized heating, implementing heating transformation by using existing cogeneration units, pure condensing generating units and low-grade waste heat around cities and industrial parks, and phasing out coal-fired boilers within the heating and steam supply scope. The boilers built by enterprises themselves are greatly restricted by policies, and a large number of steam-consuming enterprises have shifted from self-produced steam supply to steam supply by large-scale cogeneration units.

[0003] However, there is currently no relatively mature solution for high-parameter industrial steam supply above 4 MPa. Conventional solutions such as main steam supply and supplementary steam valve supply are generally adopted, but due to the over-temperature limitation of the boiler reheater, there are problems of small extraction steam volume. For 600,000-class units, it is generally not more than 100 t / h, and for 300,000-class units, it is only about half of that of 600,000-class 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-production of high-parameter industrial steam by steam-consuming enterprises.

[0004] For thermal power plants, there are a large number of instruments and equipment that need to be driven by high-pressure compressed air to operate normally during the production process. The driving power of existing conventional air compressors is driven by electric motors, and the power supply is taken from the plant power system. Due to the huge consumption of compressed air in the whole plant, the power load of the air compressor remains high, which requires a large amount of precious electric energy, resulting in a reduction in the on-grid power, an increase in the plant power consumption rate, and a decline in the operating income. Summary of the Invention

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

[0006] Therefore, an embodiment of the present invention provides a high-parameter industrial steam supply system and method for combined steam and gas production.

[0007] The present invention provides a high-parameter industrial steam supply system for combined steam and gas production, comprising:

[0008] A first-stage heat exchanger, the cold-side inlet of the first-stage heat exchanger is connected to the outlet of the deaerator, a booster pump is arranged on the pipeline between the deaerator and the cold-side inlet of the first-stage heat exchanger, the hot-side inlet of the first-stage heat exchanger is connected to the main steam extraction pipeline of the boiler, and the hot-side outlet of the first-stage heat exchanger is connected to the inlet of the deaerator;

[0009] A second-stage heat exchanger disposed downstream of the first-stage heat exchanger, wherein the cold-side inlet of the second-stage heat exchanger is connected to the cold-side outlet of the first-stage heat exchanger, the cold-side outlet of the second-stage heat exchanger is connected to the high-pressure industrial steam supply system, the hot-side inlet of the second-stage heat exchanger is connected to the reheated steam extraction pipeline of the boiler, and the hot-side outlet of the second-stage heat exchanger is connected to the steam inlet of the back-pressure steam turbine;

[0010] The back-pressure steam turbine, the exhaust port of the back-pressure steam turbine is connected to the inlet of the low-pressure cylinder, the output shaft end of the back-pressure steam turbine is connected to the gearbox coupling, the output shaft end of the gearbox coupling is connected to the overrunning clutch, the output shaft end of the overrunning clutch is connected to the motor, and the output shaft end of the motor is connected to the air compressor.

[0011] In some embodiments, the first path of condensate on the cold side of the first-stage heat exchanger is heated to saturated steam by the first path of main steam, the saturated steam is introduced into the second-stage heat exchanger and then heated to superheated steam at a certain temperature by the first path of reheated steam, the condensate after heat exchange of the first path of main steam returns to the inlet of the deaerator through a pipeline, and the first path of reheated steam enters the back-pressure steam turbine to do work to drive the air compressor to produce compressed air after heat exchange.

[0012] In some embodiments, the motor is electrically connected to the plant power system. When the output of the back-pressure steam turbine is surplus, the motor converts the surplus power output by the back-pressure steam turbine into electric energy and supplies it to the plant power system; when the output of the back-pressure steam turbine is insufficient, the motor draws power from the plant power system, and the back-pressure steam turbine and the motor jointly drive the air compressor.

[0013] In some embodiments, a first valve is provided on the pipeline between the booster pump and the outlet of the deaerator, a second valve is provided on the pipeline between the hot-side outlet of the first-stage heat exchanger and the inlet of the deaerator, a third valve is provided on the pipeline between the cold-side outlet of the second-stage heat exchanger and the high-pressure industrial steam supply system, a fourth valve and a first valve group are provided on the pipeline between the hot-side outlet of the second-stage heat exchanger and the inlet of the back-pressure steam turbine, the first valve group is disposed close to the back-pressure steam turbine, and a fifth valve is provided on the pipeline between the outlet of the back-pressure steam turbine and the inlet of the low-pressure cylinder.

[0014] In some embodiments, a second valve group is provided on the pipeline between the hot-side inlet of the first-stage heat exchanger and the main steam extraction pipeline, and a third valve group is provided on the pipeline between the hot-side inlet of the second-stage heat exchanger and the reheated steam extraction pipeline.

[0015] In some embodiments, the exhaust steam of the low-pressure cylinder enters the condenser and condenses into condensate. The condensate is divided into two paths after passing through a condensate pump, a low-pressure heater, and the deaerator in sequence. The first path of condensate enters the cold-side inlet of the first-stage heat exchanger after passing through the first valve and the booster pump, and the second path of condensate enters the boiler to be heated into main steam after being pressurized by a feed pump and heated by a high-pressure heater.

[0016] In some embodiments, the main steam at the outlet of the boiler is divided into two paths. The first path of main steam enters the first-stage heat exchanger through the hot-side inlet of the first-stage heat exchanger, and the second path of main steam enters the high-pressure cylinder to do work.

[0017] In some embodiments, the exhaust steam of the high-pressure cylinder enters the boiler again for secondary heating. The reheated steam at the outlet of the boiler is divided into two paths. The first path of reheated steam enters the second-stage heat exchanger through the hot-side inlet of the second-stage heat exchanger, and the second path of reheated steam enters the intermediate-pressure cylinder to do work.

[0018] In some embodiments, the exhaust steam of the intermediate-pressure cylinder enters the low-pressure cylinder to do work, and a butterfly valve is arranged on the pipeline between the outlet of the intermediate-pressure cylinder and the inlet of the low-pressure cylinder.

[0019] The present invention provides a high-parameter industrial steam supply method for steam-gas co-production, including the following steps:

[0020] (1) Open the first valve, and use the booster pump to boost the pressure of the first path of condensate at the outlet of the deaerator to the required pressure and then enter the cold-side inlet of the first-stage heat exchanger;

[0021] (2) The first path of main steam heats the first path of condensate into saturated steam. After heat exchange, the first path of main steam condenses and returns to the deaerator, and the saturated steam enters the cold-side inlet of the second-stage heat exchanger;

[0022] (3) The first path of reheated steam heats the saturated steam into superheated steam at a certain temperature. After heat exchange, the first path of reheated steam enters the back-pressure steam turbine to do work, and the superheated steam enters the high-pressure industrial steam supply system;

[0023] (4) The back-pressure steam turbine is connected to the motor through a gearbox coupling and an overrunning clutch, and the back-pressure steam turbine and the motor jointly drive the air compressor to operate to produce compressed air;

[0024] (5) The exhaust steam of the back-pressure steam turbine enters the low-pressure cylinder to do work.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] The present invention provides an industrial steam supply solution that can achieve a steam supply pressure above 4 MPa. Compared with conventional main steam extraction and supplementary steam valve steam supply solutions, through two-stage heat exchange, the main steam and reheated steam are respectively used to heat the saturated condensate water to the required high-parameter steam in sequence. First, a booster pump is used to boost the saturated condensate water at the outlet of the deaerator to the required pressure, then the main steam heats the high-pressure saturated condensate water into saturated steam, and finally, the high-temperature reheated steam is used to heat the saturated steam into the required superheated steam for high-pressure steam supply. The reheated steam after temperature reduction drives the back-pressure steam turbine to drive the air compressor to produce compressed air to meet the daily use of the power plant and reduce the plant power consumption rate.

[0027] By using the steam at the boiler outlet as the heat source, the present invention avoids the limitation of the extraction amount of superheated steam due to the over-temperature limitation of the boiler reheater, doubles the steam supply capacity, greatly improves the high-parameter industrial steam supply capacity of the cogeneration unit, and at the same time can produce compressed air, reduces the plant power consumption rate, realizes multi-generation of heat, electricity and gas, and further improves the economic benefits of cogeneration.

[0028] While realizing high-parameter industrial steam supply, the present invention makes use of the cascade utilization of the residual pressure of steam to reduce the plant power consumption rate, increase the on-grid power, and improve the economic efficiency of the unit's heat supply operation.

[0029] The present invention can reduce the power consumption rate of the whole plant's air compressors. The increased power generation can be supplied to the plant power system, increasing the on-grid power and improving the economic efficiency of the unit operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the drawings, wherein:

[0031] Figure 1 is a schematic diagram of the high-parameter industrial steam supply system for steam-gas co-generation of the present invention;

[0032] DESCRIPTION OF THE REFERENCE NUMERALS

[0033] 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. Butterfly valve; 12. First valve; 13. Second valve group; 14. Second valve; 15. Third valve group; 16. Fifth valve; 17. Booster pump; 18. First-stage heat exchanger; 19. Second-stage heat exchanger; 20. Back-pressure steam turbine; 21. Gearbox coupling; 22. Overrunning clutch; 23. Motor; 24. Air compressor; 25. Fourth valve; 26. Third valve; 27. First valve group; 28. High-pressure industrial steam supply system; 29. Main steam extraction pipeline; 30. Reheated steam extraction pipeline; 31. Plant power system. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where 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 by referring to the accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0035] The high-parameter industrial steam supply system and method for combined steam and gas production according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0036] As Figure 1 shown, the high-parameter industrial steam supply system for combined steam and gas production of the present invention includes a first-stage heat exchanger 18, a second-stage heat exchanger 19, a back-pressure steam turbine 20, a boiler 1, and a low-pressure cylinder 4.

[0037] The exhaust steam of the low-pressure cylinder 4 enters the condenser 10 and condenses into condensate. The condensate passes through a condensate pump 9, a low-pressure heater 8, and a deaerator 6 in sequence and then is divided into two paths. The first path of condensate enters the cold-side inlet of the first-stage heat exchanger 18 after passing through a first valve 12 and a booster pump 17. The second path of condensate is pressurized by a feed pump 7 and heated by a high-pressure heater 5 and then enters the boiler 1 to be heated into high-temperature main steam.

[0038] Specifically, the exhaust steam of the low-pressure cylinder 4 enters the condenser 10 through an exhaust steam pipeline. The exhaust steam of the low-pressure cylinder 4 condenses into condensate in the condenser 10. The outlet end of the condenser 10 is connected to the condensate pump 9. The condensate enters the low-pressure heater 8 under the action of the condensate pump 9. The outlet end of the low-pressure heater 8 is connected to the deaerator 6. The condensate enters the deaerator 6 after being heated in the low-pressure heater 8. The deaerator 6 is used to remove oxygen in the condensate to ensure the quality of the condensate. The condensate at the outlet of the deaerator 6 is divided into two paths. The first path of condensate passes through the first valve 12 and is boosted to the required pressure under the action of the booster pump 17. The boosted first path of condensate enters the first-stage heat exchanger 18 from the cold-side inlet of the first-stage heat exchanger 18. The second path of condensate is boosted under the action of the feed pump 7 and then enters the high-pressure heater 5. The second path of condensate is heated by the high-pressure heater 5 and then enters the boiler 1 for heating. The second path of condensate is heated into high-temperature main steam in the boiler 1. Among them, the outlet end of the feed pump 7 is connected to the high-pressure heater 5, the outlet end of the high-pressure heater 5 is connected to the boiler 1, and the first valve 12 is arranged on the pipeline between the booster pump 17 and the outlet of the deaerator 6. It can be understood that the flow rate of the first path of condensate can be adjusted by adjusting the first valve 12. Among them, the booster pump 17 can be a variable-frequency booster pump.

[0039] The main steam at the outlet of the boiler 1 is divided into two paths. The first path of main steam enters the first-stage heat exchanger 18 through the hot-side inlet of the first-stage heat exchanger 18. The second path of main steam enters the high-pressure cylinder 2 to do work.

[0040] Specifically, a second valve group 13 is provided on the pipeline between the hot-side inlet of the first-stage heat exchanger 18 and the main steam extraction pipeline 29. The first main steam enters the hot-side inlet of the first-stage heat exchanger 18 as a heat source after passing through the second valve group 13. After heat exchange, the first main steam condenses and returns to the deaerator 6 through the second valve 14. The second valve 14 is provided on the pipeline between the hot-side outlet of the first-stage heat exchanger 18 and the inlet of the deaerator 6. It can be understood that the flow rate of the first main steam can be adjusted by adjusting the second valve group 13. The second main steam enters the high-pressure cylinder 2 from the inlet end of the high-pressure cylinder 2 to do work.

[0041] The exhaust steam of the high-pressure cylinder 2 enters the boiler 1 again for secondary heating. The reheated steam at the outlet of the boiler 1 is divided into two paths. The first path of reheated steam enters the second-stage heat exchanger 19 through the hot-side inlet of the second-stage heat exchanger 19. The second path of reheated steam enters the intermediate-pressure cylinder 3 to do work.

[0042] Specifically, after the second main steam enters the high-pressure cylinder 2 to do work, it becomes the exhaust steam of the high-pressure cylinder 2. The exhaust steam of the high-pressure cylinder 2 is discharged from the outlet end of the high-pressure cylinder 2. The exhaust steam of the high-pressure cylinder 2 enters the boiler 1 again for secondary heating. After being heated, the exhaust steam of the high-pressure cylinder 2 becomes reheated steam and is discharged from the outlet of the boiler 1. The reheated steam at the outlet of the boiler 1 is divided into two paths. Among them, the first path of reheated steam enters the second-stage heat exchanger 19 as a heat source through the hot-side inlet of the second-stage heat exchanger 19. After heat exchange, the first path of reheated steam enters the back-pressure steam turbine 20 to do work. The second path of reheated steam enters the intermediate-pressure cylinder 3 to do work. The exhaust steam of the intermediate-pressure cylinder 3 enters the low-pressure cylinder 4 to do work through the butterfly valve 11. Among them, a third valve group 15 is provided on the pipeline between the hot-side inlet of the second-stage heat exchanger 19 and the hot reheat extraction pipeline. A fourth valve 25 and a first valve group 27 are provided on the pipeline between the hot-side outlet of the second-stage heat exchanger 19 and the inlet of the back-pressure steam turbine 20. The first valve group 27 is arranged close to the back-pressure steam turbine 20. The butterfly valve 11 is provided on the pipeline between the outlet of the intermediate-pressure cylinder 3 and the inlet of the low-pressure cylinder 4.

[0043] The cold-side inlet of the first-stage heat exchanger 18 is connected to the outlet of the deaerator 6. A booster pump 17 is provided on the pipeline between the deaerator 6 and the cold-side inlet of the first-stage heat exchanger 18. The hot-side inlet of the first-stage heat exchanger 18 is connected to the main steam extraction pipeline 29 of the boiler 1. The hot-side outlet of the first-stage heat exchanger 18 is connected to the inlet of the deaerator 6.

[0044] Specifically, the first path of condensate water at the outlet of the deaerator 6 enters the first-stage heat exchanger 18 from the cold-side inlet of the first-stage heat exchanger 18 after being boosted by the booster pump 17. The first main steam enters the first-stage heat exchanger 18 from the hot side of the first-stage heat exchanger 18. The first main steam heats the first path of condensate water as a heat source. The first path of condensate water on the cold side of the first-stage heat exchanger 18 is heated to saturated steam by the first main steam. The first main steam condenses into condensate water after heat exchange and flows out from the hot-side outlet of the first-stage heat exchanger 18 and then enters the deaerator 6.

[0045] The cold-side inlet of the second-stage heat exchanger 19 is connected to the cold-side outlet of the first-stage heat exchanger 18, the cold-side outlet of the second-stage heat exchanger 19 is connected to the high-pressure industrial steam supply system 28, the hot-side inlet of the second-stage heat exchanger 19 is connected to the reheated steam extraction pipeline 30 of the boiler 1, and the hot-side outlet of the second-stage heat exchanger 19 is connected to the steam inlet of the back-pressure steam turbine 20.

[0046] Specifically, the second-stage heat exchanger 19 is arranged downstream of the first-stage heat exchanger 18. The cold-side inlet of the second-stage heat exchanger 19 is connected to the cold-side outlet of the first-stage heat exchanger 18. The saturated steam flows out from the cold-side outlet of the first-stage heat exchanger 18 and enters the second-stage heat exchanger 19 from the cold-side inlet of the second-stage heat exchanger 19. The first path of reheated steam enters the second-stage heat exchanger 19 from the hot-side inlet of the second-stage heat exchanger 19 through the third valve group 15 to heat the saturated steam. In the second-stage heat exchanger 19, the saturated steam is heated into superheated steam at a certain temperature. The superheated steam flows out from the cold-side outlet end of the second-stage heat exchanger 19 and is supplied to the high-pressure industrial steam supply system 28 through the third valve 26. The first path of reheated steam after heat exchange successively passes through the fourth valve 25 and the first valve group 27 and enters the back-pressure steam turbine 20 to do work. The back-pressure steam turbine 20 drives the air compressor 24 to operate to produce compressed air.

[0047] The exhaust port of the back-pressure steam turbine 20 is connected to the inlet of the low-pressure cylinder 4. The output shaft end of the back-pressure steam turbine 20 is connected to the gearbox coupling 21. The output shaft end of the gearbox coupling 21 is connected to the overrunning clutch 22. The output shaft end of the overrunning clutch 22 is connected to the motor 23. The output shaft end of the motor 23 is connected to the air compressor 24.

[0048] Specifically, a fifth valve 16 is arranged on the pipeline between the outlet of the back-pressure steam turbine 20 and the inlet of the low-pressure cylinder 4. After the exhaust steam of the back-pressure steam turbine 20 passes through the fifth valve 16, it finally enters the low-pressure cylinder 4 through the butterfly valve 11 to do work. The output shaft end of the back-pressure steam turbine 20 is connected to the gearbox coupling 21. The output shaft end of the gearbox and the coupling is connected to the overrunning clutch 22. The output shaft end of the overrunning clutch 22 is connected to the motor 23. The output shaft end of the motor 23 is connected to the air compressor 24, so that the back-pressure steam turbine 20 can drive the air compressor 24 to operate. Thus, the air compressor 24 can be driven by both steam and electricity.

[0049] The motor 23 is electrically connected to the plant power system 31. When the output of the back-pressure steam turbine 20 is surplus, the motor 23 converts the surplus power output by the back-pressure steam turbine 20 into electric energy and supplies it to the plant power system 31. When the output of the back-pressure steam turbine 20 is insufficient, the motor 23 draws power from the plant power system 31, and the back-pressure steam turbine 20 and the motor 23 jointly drive the air compressor 24.

[0050] Specifically, the steam source of the back-pressure steam turbine 20 comes from the first reheat steam after temperature reduction by the second-stage heat exchanger 19 of the unit. The back-pressure steam turbine 20 drives the motor 23 and the air compressor 24 to operate simultaneously. The back-pressure steam turbine 20 undertakes the power consumption of the motor 23, thereby reducing the power consumption of the air compressor 24 system. When the output of the back-pressure steam turbine 20 is surplus, the motor 23 automatically changes to the power generation state, converting the surplus power output by the back-pressure steam turbine 20 into electric energy and supplying it to the unit's auxiliary power system 31. When the output of the back-pressure steam turbine 20 is insufficient to meet the working requirements of the air compressor 24, the back-pressure steam turbine 20 and the motor 23 jointly drive the air compressor 24 to work. The motor 23 changes to the power-consuming state, draws power from the auxiliary power system 31, and shares the remaining power consumption of the air compressor 24, thereby reducing the power consumption of the air compressor 24 system. When the back-pressure steam turbine 20 fails, it is disconnected from the operation, and the air compressor 24 is completely driven by the motor 23 to operate.

[0051] The high-parameter industrial steam supply method for steam-gas co-production using the steam-gas co-production high-parameter industrial steam supply system of the present invention includes the following steps:

[0052] (1) Open the first valve 12, and use the booster pump 17 to boost the pressure of the first condensate water at the outlet of the deaerator 6 to the required pressure and then enter the cold-side inlet of the first-stage heat exchanger 18;

[0053] (2) The first main steam heats the first condensate water into saturated steam. After heat exchange, the first main steam condenses and returns to the deaerator 6, and the saturated steam enters the cold-side inlet of the second-stage heat exchanger 19;

[0054] (3) The first reheat steam heats the saturated steam into superheated steam at a certain temperature. After heat exchange, the first reheat steam enters the back-pressure steam turbine 20 to do work, and the superheated steam enters the high-pressure industrial steam supply system 28;

[0055] (4) The back-pressure steam turbine 20 is connected to the motor 23 through the gearbox coupling 21 and the overrunning clutch 22. The back-pressure steam turbine 20 and the motor 23 jointly drive the air compressor 24 to operate to produce compressed air;

[0056] (5) The exhaust steam of the back-pressure steam turbine 20 enters the low-pressure cylinder 4 to do work.

[0057] Specifically, when the unit starts to supply heat extraction steam, open the first valve 12 and the booster pump 17. Use the booster pump 17 to boost the pressure of the first condensate water at the outlet of the deaerator 6 to the required pressure. The boosted first condensate water enters the cold side of the first-stage heat exchanger 18. The first main steam enters the first-stage heat exchanger 18 to exchange heat with the first condensate water. The first condensate water at the outlet of the deaerator 6 is heated into saturated steam. The first main steam condenses into condensate and returns to the inlet of the deaerator 6. The saturated steam at the outlet of the first-stage heat exchanger 18 enters the cold side of the second-stage heat exchanger 19.

[0058] The second main steam enters the high-pressure cylinder 2 from the inlet end of the high-pressure cylinder 2 to do work. The exhaust steam of the high-pressure cylinder 2 enters the boiler 1 again for secondary heating. The reheated steam at the outlet of the boiler 1 is divided into two paths. The first path of reheated steam enters the second-stage heat exchanger 19 to exchange heat with the saturated steam at the outlet of the first-stage heat exchanger 18. The saturated steam at the outlet of the first-stage heat exchanger 18 is heated to superheated steam at the required temperature and then enters the high-pressure industrial steam supply system 28. After the temperature of the first path of reheated steam in the second-stage heat exchanger 19 drops, it enters the back-pressure steam turbine 20 to drive it to do work. The second path of reheated steam enters the intermediate-pressure cylinder 3 to do work, and the exhaust steam of the intermediate-pressure cylinder 3 enters the low-pressure cylinder 4 to do work through the butterfly valve 11.

[0059] The back-pressure steam turbine 20 is connected to the motor 23 through the gearbox coupling 21 and the overrunning clutch 22 to jointly drive the air compressor 24 to operate. The electrical output end of the motor 23 is connected to the plant power system 31. When the output of the back-pressure steam turbine 20 has surplus in addition to driving the air compressor 24, at this time, the motor 23 automatically changes to the power generation state, converts the surplus power output by the back-pressure steam turbine 20 into electric energy, and supplies it to the plant power system 31 of the unit for supplying the auxiliary equipment in the plant. When the output of the back-pressure steam turbine 20 is insufficient, at this time, the motor 23 automatically changes to the power consumption state, takes power from the plant power system 31, supplements the remaining power consumption required by the air compressor 24, and jointly drives the air compressor 24 to operate with the back-pressure steam turbine 20. The exhaust steam of the back-pressure steam turbine 20 after doing work enters the low-pressure cylinder 4. When the back-pressure steam turbine 20 fails, the back-pressure steam turbine 20 is disconnected from the system, and the motor 23 of the air compressor 24 automatically changes to the power consumption state, takes power from the plant power system 31, and drives the air compressor 24 to operate alone.

[0060] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", 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 expressions of the above terms may be directed to different embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. 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 indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0062] Although 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 spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A high-parameter industrial steam supply system for combined production of steam and gas, characterized in that Comprising: A first-stage heat exchanger, the cold-side inlet of the first-stage heat exchanger is connected to the outlet of the deaerator, a booster pump is provided on the pipeline between the deaerator and the cold-side inlet of the first-stage heat exchanger, the hot-side inlet of the first-stage heat exchanger is connected to the main steam extraction pipeline of the boiler, and the hot-side outlet of the first-stage heat exchanger is connected to the inlet of the deaerator; A second-stage heat exchanger provided downstream of the first-stage heat exchanger, the cold-side inlet of the second-stage heat exchanger is connected to the cold-side outlet of the first-stage heat exchanger, the cold-side outlet of the second-stage heat exchanger is connected to the high-pressure industrial steam supply system, the hot-side inlet of the second-stage heat exchanger is connected to the reheated steam extraction pipeline of the boiler, and the hot-side outlet of the second-stage heat exchanger is connected to the steam inlet of the back-pressure steam turbine; The back-pressure steam turbine, the exhaust port of the back-pressure steam turbine is connected to the inlet of the low-pressure cylinder, the output shaft end of the back-pressure steam turbine is connected to the gearbox coupling, the output shaft end of the gearbox coupling is connected to the overrunning clutch, the output shaft end of the overrunning clutch is connected to the motor, and the output shaft end of the motor is connected to the air compressor; The exhaust steam of the low-pressure cylinder enters the condenser and condenses into condensate. The condensate passes through the condensate pump, low-pressure heater, and the deaerator in sequence and then is divided into two paths. The first path of condensate enters the cold-side inlet of the first-stage heat exchanger after passing through the first valve and the booster pump. The second path of condensate is pressurized by the feed water pump and heated by the high-pressure heater and then enters the boiler to be heated into main steam. The main steam at the outlet of the boiler is divided into two paths. The first path of main steam enters the first-stage heat exchanger through the hot-side inlet of the first-stage heat exchanger. The second path of main steam enters the high-pressure cylinder to do work. The exhaust steam of the high-pressure cylinder enters the boiler again for secondary heating. The reheated steam at the outlet of the boiler is divided into two paths. The first path of reheated steam enters the second-stage heat exchanger through the hot-side inlet of the second-stage heat exchanger. The second path of reheated steam enters the intermediate-pressure cylinder to do work.

2. The system according to claim 1, wherein The first path of condensate on the cold side of the first-stage heat exchanger is heated into saturated steam by the first path of main steam. The saturated steam is introduced into the second-stage heat exchanger and then heated into superheated steam at a certain temperature by the first path of reheated steam. The condensed water after heat exchange of the first path of main steam returns to the inlet of the deaerator through the pipeline. The first path of reheated steam after heat exchange enters the back-pressure steam turbine to do work and drives the air compressor to operate to produce compressed air.

3. The system according to claim 1, characterized in that, The motor is electrically connected to the plant power system. When the output of the back-pressure steam turbine is surplus, the motor converts the surplus power output by the back-pressure steam turbine into electric energy and supplies it to the plant power system; when the output of the back-pressure steam turbine is insufficient, the motor draws power from the plant power system, and the back-pressure steam turbine and the motor jointly drive the air compressor.

4. The system according to claim 2, wherein A first valve is provided on the pipeline between the booster pump and the outlet of the deaerator. A second valve is provided on the pipeline between the hot-side outlet of the first-stage heat exchanger and the inlet of the deaerator. A third valve is provided on the pipeline between the cold-side outlet of the second-stage heat exchanger and the high-pressure industrial steam supply system. A fourth valve and a first valve group are provided on the pipeline between the hot-side outlet of the second-stage heat exchanger and the inlet of the back-pressure steam turbine. The first valve group is arranged close to the back-pressure steam turbine. A fifth valve is provided on the pipeline between the outlet of the back-pressure steam turbine and the inlet of the low-pressure cylinder.

5. The system according to claim 1, wherein A second valve group is provided on the pipeline between the hot-side inlet of the first-stage heat exchanger and the main steam extraction pipeline. A third valve group is provided on the pipeline between the hot-side inlet of the second-stage heat exchanger and the reheat steam extraction pipeline.

6. The system according to claim 5, wherein The exhaust steam of the medium-pressure cylinder enters the low-pressure cylinder to do work. A butterfly valve is provided on the pipeline between the outlet of the medium-pressure cylinder and the inlet of the low-pressure cylinder.

7. A high-parameter industrial steam supply method for combined production of steam and gas, characterized in that, Using the system according to any one of claims 1-6, comprising the following steps: (1) Open the first valve, and use the booster pump to boost the pressure of the first path of condensate water at the outlet of the deaerator to the required pressure and then enter the cold-side inlet of the first-stage heat exchanger; (2) The first path of main steam heats the first path of condensate water into saturated steam. After heat exchange, the first path of main steam condenses and returns to the deaerator, and the saturated steam enters the cold-side inlet of the second-stage heat exchanger; (3) The first path of reheat steam heats the saturated steam into superheated steam at a certain temperature. After heat exchange, the first path of reheat steam enters the back-pressure steam turbine to do work, and the superheated steam enters the high-pressure industrial steam supply system; (4) The back-pressure steam turbine is connected to the motor through a gearbox coupling and an overrunning clutch. The back-pressure steam turbine and the motor jointly drive the air compressor to operate to produce compressed air; (5) The exhaust steam of the back-pressure steam turbine enters the low-pressure cylinder to do work.

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