A kind of industrial steam supply system is adjusted by reducing load under the restriction of high parameter large-scale steam

Abstract

The application discloses an industrial steam supply system capable of reducing load and saving energy under the limitation of high parameters and large-scale steam use of unit load lower limit, and belongs to the technical field of industrial steam supply systems. In order to solve the problem that the commonly used mode of reducing load and supplementing industrial steam supply usually selects high bypass or main steam of a unit as a steam source, high-grade energy is wasted, and the demand of large-scale steam use and power grid dispatching for the unit load lower limit cannot be met, the application adopts heat re-extraction steam in cooperation with middle connection door participation regulation, so that the steam supply mode can be flexibly switched according to different demands of electric and heat loads, the original industrial steam supply mode is adopted when high power generation load and large steam supply load occur, the heat re-extraction steam mode is adopted when small steam supply load occurs, and the heat re-extraction adjustable steam mode is adopted when middle-low power generation load and large steam supply load occur. Finally, the unit can meet the steam demand of high parameters and large-scale extreme conditions of heat users by using a heat source with a lower main steam grade, ensure safe operation of the unit, and reduce the load to the demand of power grid dispatching.

Description

Technical Field

[0001] This invention belongs to the technical field of industrial steam supply systems, specifically relating to an industrial steam supply system for load reduction and energy saving adjustment where the lower limit of unit load is limited by large-scale steam consumption with high parameters. Background Technology

[0002] The parameters of steam used in industrial production are generally higher than those used for heating, and the scale of steam consumption is huge during the heating season. When the unit is the only heat source for district heating, it is necessary to ensure stable heating pressure and flow to guarantee the production and facilities of important users. If the unit trips and the heating is interrupted during operation, it will have an immeasurable impact on important users and will seriously threaten the safe and stable operation of important users' production and production facilities. Therefore, it is generally not involved in the regional power grid dispatch, that is, the original design conditions of the unit did not take into account the steam supply requirements when the grid is heavily dispatched.

[0003] However, to meet the demands of new energy development, during the heating season when industrial steam demand is high (peak demand of 300-350 tons / hour, steam source pressure requirement above 1.2MPa), if the unit reduces its load by less than 60% in response to grid dispatch, it cannot guarantee the user's steam consumption and parameters. Furthermore, some steam-consuming equipment within the unit's internal system may experience reduced parameters, affecting the overall safe and stable operation of the unit. Simultaneously, because the unit's load cannot meet grid dispatch requirements, it also faces high spot market allocation and performance evaluation costs.

[0004] Currently, the commonly used methods for load reduction and supplementing industrial steam supply mostly use high-voltage bypass or main steam from the unit as the steam source, which results in the waste of high-grade energy and cannot meet the lower limit requirements of large-scale steam consumption and grid dispatch for unit load. Summary of the Invention

[0005] This invention addresses the problem that current methods for load reduction and supplementing industrial steam supply often use high-voltage bypass or main steam from the generating unit as the steam source, resulting in the waste of high-grade energy and failing to meet the requirements of large-scale steam consumption and grid dispatch for the lower limit of generating unit load. Therefore, this invention provides a load reduction and energy-saving adjustment industrial steam supply system that limits the lower limit of generating unit load to large-scale steam consumption with high parameters.

[0006] An industrial steam supply system for load reduction and energy saving adjustment, where the lower limit of unit load is limited by large-scale steam consumption with high parameters, is disclosed. The system includes a steam turbine unit comprising a high-pressure cylinder, an intermediate-pressure cylinder, and a low-pressure cylinder. The system also includes an existing hot reheat header, a hot reheat extraction pipeline, a four-stage extraction pipeline for internal supply, a four-stage extraction pipeline for external supply, a hot reheat extraction tee, and a No. 1 interface tee. The existing hot reheat header is located at the inlet end of the intermediate-pressure cylinder and connected to it, with its outlet end connected to the steam turbine unit. A hot reheat extraction tee is installed on the existing hot reheat header, and the inlet end of the hot reheat extraction pipeline connects to the existing hot reheat header via the hot reheat extraction tee. The main pipe is connected to the internal steam supply pipeline and the external steam supply pipeline of the four-section extraction steam are both set on the extraction end of the intermediate pressure cylinder. The steam inlet end of the internal steam supply pipeline of the four-section extraction steam is connected to the extraction end of the intermediate pressure cylinder. The steam outlet end of the internal steam supply pipeline of the four-section extraction steam is connected to the small steam turbine and the heater of the plant's heating network. The steam inlet end of the external steam supply pipeline of the four-section extraction steam is connected to the extraction end of the intermediate pressure cylinder. The steam outlet end of the external steam supply pipeline of the four-section extraction steam is connected to the heat users outside the plant. The external steam supply pipeline of the four-section extraction steam is equipped with a No. 1 interface tee. The steam outlet end of the hot re-extraction steam pipeline is connected to the external steam supply pipeline of the four-section extraction steam through the No. 1 interface tee.

[0007] Furthermore, from the steam inlet to the steam outlet, the hot re-extraction steam pipeline is connected in series with a No. 1 pneumatic quick-closing valve, a pneumatic check valve, an electric gate valve, a desuperheating and pressure reducing device, an electric butterfly valve, and a hot re-extraction steam flow meter.

[0008] Furthermore, the four-section steam extraction external steam supply pipeline is connected in series from the steam inlet end to the steam outlet end with an electric regulating valve, a pneumatic check valve, an electric gate valve, and a desuperheater.

[0009] Furthermore, the four-section extraction steam supply pipeline includes an internal turbine steam supply branch pipe and a heating network branch pipe. The steam inlet end of the internal turbine steam supply branch pipe is connected to the extraction end of the intermediate pressure cylinder, and the steam outlet end of the internal turbine steam supply branch pipe is connected to the small steam turbine in the plant. The steam inlet end of the heating network branch pipe is connected to the internal turbine steam supply branch pipe through the heating network heater and the small turbine diversion tee, and the steam outlet end of the heating network branch pipe is connected to the heating network heater in the plant.

[0010] Furthermore, the internal steam supply branch pipe is connected in series from the steam inlet end to the steam outlet end with an internal steam supply pipeline pneumatic check valve, an internal steam supply pipeline pneumatic check valve, and an internal steam supply pipeline electric gate valve.

[0011] The heating network heater and the small turbine diversion tee are located between the electric gate valve of the internal steam supply pipeline and the small steam turbine in the plant;

[0012] An electric gate valve for the steam supply pipeline of the heating network heater is connected in series on the heating branch pipeline of the heating network.

[0013] Furthermore, a No. 1 intermediate regulating valve is connected in series on the original hot reheat main pipe. The No. 1 intermediate regulating valve is located between the turbine unit and the hot reheat extraction steam tee. A No. 2 intermediate regulating valve is connected in parallel on the No. 1 intermediate regulating valve. The reheat steam passes through the original hot reheat main pipe and the No. 1 and No. 2 intermediate regulating valves and enters the intermediate pressure cylinder.

[0014] Furthermore, the steam supply system also includes a steam replenishment pipeline. The steam inlet end of the steam replenishment pipeline is connected to the external steam supply pipeline of the fourth section through the No. 1 steam replenishment interface tee. The steam outlet end of the steam replenishment pipeline is connected to the heating branch pipeline of the heating network through the No. 2 steam replenishment interface tee. The steam replenishment pipeline is connected in series with a steam replenishment pipeline electric butterfly valve and a steam replenishment pipeline flow meter from the steam inlet end to the steam outlet end.

[0015] Furthermore, a new pneumatic quick-connect valve is connected in series on the heating branch pipeline of the heating network, and the new pneumatic quick-connect valve is located between the No. 2 steam injection interface tee and the heating network heater and the small turbine diversion tee.

[0016] Furthermore, the steam supply system also includes a steam replenishment pipeline. The steam inlet end of the steam replenishment pipeline is connected to the hot re-extraction steam pipeline through the No. 3 steam replenishment interface tee, and the steam outlet end of the steam replenishment pipeline is connected to the internal small unit steam supply branch pipe through the No. 4 steam replenishment interface tee. The steam replenishment pipeline is connected in series with a steam replenishment pipeline electric butterfly valve and a steam replenishment pipeline flow meter from the steam inlet end to the steam outlet end.

[0017] Furthermore, a No. 2 pneumatic quick-closing valve is connected in series on the four-section extraction steam supply pipeline. The No. 2 pneumatic quick-closing valve is located between the electric gate valve of the internal steam supply pipeline and the heat network heater and the small turbine diversion tee.

[0018] The beneficial effects of this application compared to the prior art are:

[0019] This application provides an industrial steam supply system for load reduction and energy saving adjustment when the lower limit of unit load is limited by high-parameter, large-scale steam consumption. While retaining the original large-scale, high-parameter industrial steam supply system, it allows for flexible switching of the steam supply mode according to different electricity and heat load demands. During the heating season when industrial steam demand is high (peak 300-350 tons / hour, steam source pressure requirement above 1.2 MPa), the unit can reduce its load from the restricted 60% lower limit to 30%-40%. Ultimately, the unit can meet the high-parameter and large-scale steam demand of heat users under extreme conditions by using heat sources with a lower grade than the main steam, while ensuring the safe operation of the unit and adapting to the load dispatching requirements of the power grid for units of the same capacity.

[0020] This application provides an industrial steam supply system for load reduction and energy saving adjustment when the lower limit of unit load is limited by high-parameter, large-scale steam consumption. It employs hot reheat extraction combined with intermediate valve regulation, allowing for flexible switching of the steam supply mode according to different electricity and heat load demands. Under high power generation and large steam supply loads, the original industrial steam supply mode is used; under low steam supply loads, a hot reheat extraction mode without adjustment is used; and under medium-low power generation and large steam supply loads, a hot reheat adjustable extraction mode is used. Ultimately, this enables the unit to meet the steam demand of heat users under extreme conditions of high parameters and large-scale operation using heat sources with a lower grade than main steam, while ensuring safe unit operation and reducing the load to meet grid dispatch requirements. Attached Figure Description

[0021] Figure 1 The following is a general diagram of the industrial steam supply system for load reduction and energy saving adjustment, where the lower limit of the unit load is limited by high-parameter large-scale steam consumption, as described in this application (specific implementation method one);

[0022] Figure 2 The following is a general diagram of the industrial steam supply system for load reduction and energy saving adjustment, where the lower limit of the unit load is limited by high-parameter large-scale steam consumption, as described in this application (specific implementation method two);

[0023] In the diagram: 1. High-pressure cylinder; 2. Medium-pressure cylinder; 3. Low-pressure cylinder; 4. No. 1 medium-pressure regulating valve; 5. No. 2 medium-pressure regulating valve; 6. Existing hot reheat main pipe; 7. Hot reheat extraction steam tee; 8. No. 1 pneumatic quick-closing valve; 9. Pneumatic check valve; 10. Electric gate valve; 11. Desuperheater and pressure reducer; 12. Electric butterfly valve; 13. Hot reheat extraction steam flow meter; 14. No. 1 interface tee; 15. No. 1 make-up steam interface tee; 16. Make-up steam pipeline electric butterfly valve; 17. Make-up steam pipeline flow meter; 18. No. 2 make-up steam interface tee; 19. External steam supply pipeline electric regulating valve; 20. External steam supply pipeline pneumatic check valve. Valves: 21 Electric gate valve for external steam supply pipeline; 22 Desuperheater for external steam supply pipeline; 23 Pneumatic check valve for internal steam supply pipeline; 24 Pneumatic check valve for internal steam supply pipeline; 25 Electric gate valve for internal steam supply pipeline; 26 Diverter tee for heating network heater and small unit; 27 Steam supply branch pipe for internal small unit; 28 Heating network branch pipeline; 29 Newly added pneumatic quick-connect valve for heating network heater steam supply pipeline; 30 Electric gate valve for heating network heater steam supply pipeline; 31 No. 2 pneumatic quick-closing valve; 32 No. 4 steam replenishment interface tee; 33 No. 3 steam replenishment interface tee. Detailed Implementation

[0024] Specific implementation method one: Combining Figure 1This embodiment describes an industrial steam supply system for load reduction and energy saving adjustment, where the lower limit of unit load is limited by large-scale steam consumption with high parameters. The steam supply system includes a steam turbine unit, which includes a high-pressure cylinder 1, an intermediate-pressure cylinder 2, and a low-pressure cylinder 3. The steam supply system also includes an existing hot reheat header 6, a hot reheat extraction steam pipeline, a four-stage extraction steam pipeline for internal supply, a four-stage extraction steam pipeline for external supply, a hot reheat extraction steam tee 7, and a No. 1 interface tee 14. The existing hot reheat header 6 is located on the steam inlet end of the intermediate-pressure cylinder 2 and is connected to the intermediate-pressure cylinder 2. The steam outlet end of the existing hot reheat header 6 is connected to the steam turbine unit. The existing hot reheat header 6 is equipped with a hot reheat extraction steam tee 7. The steam inlet end of the hot reheat extraction steam pipeline is connected to the steam turbine unit. The re-extraction steam tee 7 is connected to the original hot re-extraction main pipe 6. The four-stage extraction steam internal supply pipeline and the four-stage extraction steam external supply pipeline are both set on the extraction end of the intermediate pressure cylinder 2. The steam inlet end of the four-stage extraction steam internal supply pipeline is connected to the extraction end of the intermediate pressure cylinder 2. The steam outlet end of the four-stage extraction steam internal supply pipeline is connected to the small steam turbine in the plant and the heater of the plant's heating network. The steam inlet end of the four-stage extraction steam external supply pipeline is connected to the extraction end of the intermediate pressure cylinder 2. The steam outlet end of the four-stage extraction steam external supply pipeline is connected to the heat user outside the plant. The four-stage extraction steam external supply pipeline is equipped with a No. 1 interface tee 14. The steam outlet end of the hot re-extraction steam pipeline is connected to the four-stage extraction steam external supply pipeline through the No. 1 interface tee 14.

[0025] The hot re-extraction steam pipeline is connected in series from the steam inlet end to the steam outlet end with a pneumatic quick-closing valve 8, a pneumatic check valve 9, an electric gate valve 10, a desuperheating and pressure reducing device 11, an electric butterfly valve 12, and a hot re-extraction steam flow meter 13.

[0026] The four-section steam extraction external steam supply pipeline is connected in series from the steam inlet end to the steam outlet end with an electric regulating valve 19, a pneumatic check valve 20, an electric gate valve 21, and a desuperheater 22.

[0027] The four-stage extraction steam supply pipeline includes an internal turbine steam supply branch pipe 27 and a heating network branch pipe 28. The steam inlet end of the internal turbine steam supply branch pipe 27 is connected to the extraction end of the intermediate pressure cylinder 2, and the steam outlet end of the internal turbine steam supply branch pipe 27 is connected to the small steam turbine in the plant. The steam inlet end of the heating network branch pipe 28 is connected to the internal turbine steam supply branch pipe 27 through the heating network heater and the small turbine diversion tee 26, and the steam outlet end of the heating network branch pipe 28 is connected to the heating network heater in the plant.

[0028] The internal steam supply branch pipe 27 is connected in series from the steam inlet end to the steam outlet end with the internal steam supply pipeline pneumatic check valve 23, the internal steam supply pipeline pneumatic check valve 24, and the internal steam supply pipeline electric gate valve 25.

[0029] The heating network heater and the small turbine diversion tee 26 is located between the electric gate valve 25 of the internal steam supply pipeline and the small steam turbine in the plant;

[0030] An electric gate valve 30 for the steam supply pipeline of the heating network heater is connected in series on the heating network branch pipeline 28.

[0031] A No. 1 intermediate regulating valve 4 is connected in series on the original hot reheat main pipe 6. The No. 1 intermediate regulating valve 4 is located between the turbine unit and the hot reheat extraction steam tee 7. A No. 2 intermediate regulating valve 5 is connected in parallel on the No. 1 intermediate regulating valve 4. The reheat steam passes through the original hot reheat main pipe 6, the No. 1 intermediate regulating valve 4 and the No. 2 intermediate regulating valve 5 and enters the intermediate pressure cylinder 2.

[0032] The steam supply system also includes a steam replenishment pipeline. The steam inlet end of the steam replenishment pipeline is connected to the external steam supply pipeline of the fourth section through the No. 1 steam replenishment interface tee 15. The steam outlet end of the steam replenishment pipeline is connected to the heating branch pipeline 28 of the heating network through the No. 2 steam replenishment interface tee 18. The steam replenishment pipeline is connected in series with the steam replenishment pipeline electric butterfly valve 16 and the steam replenishment pipeline flow meter 17 from the steam inlet end to the steam outlet end.

[0033] A new pneumatic quick-connect valve 29 is connected in series on the heating branch pipe 28 of the heating network heater steam supply pipe. The new pneumatic quick-connect valve 29 of the heating network heater steam supply pipe is located between the No. 2 steam injection interface tee 18 and the heating network heater and small turbine diversion tee 26.

[0034] This embodiment provides an industrial steam supply system for load reduction and energy saving adjustment when the lower limit of unit load is limited by high-parameter large-scale steam consumption. It is mainly for regional single heat source units. In order to ensure the production and facility heating needs of important users, when the lower limit of unit load cannot meet the peak-shaving needs of units of the same capacity and the stable operation of its own system (some pipelines overheat or small steam-consuming units cannot operate normally) under the condition of large-scale steam consumption and high parameters, appropriate quality heat sources are used to supplement steam supply while ensuring the original steam supply mode. This enables the unit to flexibly adjust industrial steam supply for energy saving according to different matching needs of heat load and electrical load. The working principle of this application is described below in three working conditions.

[0035] Operating Condition 1: Under high power generation load and large steam supply load, the original industrial steam supply method is adopted:

[0036] During periods of high power generation and large steam supply loads, the original industrial steam supply method is adopted: after the four-stage extraction steam is drawn from the intermediate pressure cylinder, part of it is supplied internally through the pneumatic check valve 23, the pneumatic check valve 24, and the electric gate valve 25 of the internal steam supply pipeline to ensure the steam supply for the plant's small turbines and heating network heaters; the other part is supplied externally through the electric regulating valve 19, the pneumatic check valve 20, the electric gate valve 21, and the desuperheater 22 of the external steam supply pipeline.

[0037] Operating Condition 2: Under low steam supply load, the extraction steam method without thermal re-adjustment is used:

[0038] When steam consumption is relatively low and electrical load needs to be appropriately reduced, steam is drawn from the hot re-extraction pipeline, passing through pneumatic quick-closing valve 8, pneumatic check valve 9, electric gate valve 10, desuperheating and pressurizing device 11, electric butterfly valve 12, hot re-extraction steam flow meter 13, and No. 1 interface tee 14 to connect to the original four-stage extraction steam external supply pipeline. Part of the steam is supplied externally, and the other part is connected to the steam supply pipeline for steam-consuming equipment in the plant through No. 1 makeup steam interface tee 15. The makeup steam passes through the makeup steam pipeline electric butterfly valve 1. 6. The steam supply pipeline flow meter 17 and the No. 2 steam supply interface tee 18 are connected to the heating network branch pipeline 28. During the non-heating season, the electric gate valve 30 of the heating network heater steam supply pipeline is closed. The pneumatic quick-connect valve 29, the heating network branch pipeline 28, and the heating network heater and small turbine diversion tee 26 are connected to the internal small turbine steam supply branch pipeline 27. During the heating season, the valve needs to be opened to supply steam to the plant's internal heating network heater, ensuring the safe and stable operation of the plant's steam-using equipment during low electrical load.

[0039] Operating Condition 3: The heat recovery adjustable steam extraction method is used under medium-low power generation load and high steam supply load conditions.

[0040] In this operating condition, based on operating condition 2, the newly added No. 1 intermediate regulating valve 4 and No. 2 intermediate regulating valve 5 cooperate to regulate the extraction steam volume, extraction steam parameters and unit inlet steam parameters, thereby ensuring the heat user's heat use safety and the unit's operating safety.

[0041] Specific Implementation Method Two: Combining Figure 2 This embodiment describes an industrial steam supply system for load reduction and energy saving adjustment, where the lower limit of unit load is limited by large-scale steam consumption with high parameters. The steam supply system includes a steam turbine unit, which includes a high-pressure cylinder 1, an intermediate-pressure cylinder 2, and a low-pressure cylinder 3. The steam supply system also includes an existing hot reheat header 6, a hot reheat extraction steam pipeline, a four-stage extraction steam pipeline for internal supply, a four-stage extraction steam pipeline for external supply, a hot reheat extraction steam tee 7, and a No. 1 interface tee 14. The existing hot reheat header 6 is located on the steam inlet end of the intermediate-pressure cylinder 2 and is connected to the intermediate-pressure cylinder 2. The steam outlet end of the existing hot reheat header 6 is connected to the steam turbine unit. The existing hot reheat header 6 is equipped with a hot reheat extraction steam tee 7. The steam inlet end of the hot reheat extraction steam pipeline is connected to the steam turbine unit. The re-extraction steam tee 7 is connected to the original hot re-extraction main pipe 6. The four-stage extraction steam internal supply pipeline and the four-stage extraction steam external supply pipeline are both set on the extraction end of the intermediate pressure cylinder 2. The steam inlet end of the four-stage extraction steam internal supply pipeline is connected to the extraction end of the intermediate pressure cylinder 2. The steam outlet end of the four-stage extraction steam internal supply pipeline is connected to the small steam turbine in the plant and the heater of the plant's heating network. The steam inlet end of the four-stage extraction steam external supply pipeline is connected to the extraction end of the intermediate pressure cylinder 2. The steam outlet end of the four-stage extraction steam external supply pipeline is connected to the heat user outside the plant. The four-stage extraction steam external supply pipeline is equipped with a No. 1 interface tee 14. The steam outlet end of the hot re-extraction steam pipeline is connected to the four-stage extraction steam external supply pipeline through the No. 1 interface tee 14.

[0042] The hot re-extraction steam pipeline is connected in series from the steam inlet end to the steam outlet end with a pneumatic quick-closing valve 8, a pneumatic check valve 9, an electric gate valve 10, a desuperheating and pressure reducing device 11, an electric butterfly valve 12, and a hot re-extraction steam flow meter 13.

[0043] The four-section steam extraction external steam supply pipeline is connected in series from the steam inlet end to the steam outlet end with an electric regulating valve 19, a pneumatic check valve 20, an electric gate valve 21, and a desuperheater 22.

[0044] The four-stage extraction steam supply pipeline includes an internal turbine steam supply branch pipe 27 and a heating network branch pipe 28. The steam inlet end of the internal turbine steam supply branch pipe 27 is connected to the extraction end of the intermediate pressure cylinder 2, and the steam outlet end of the internal turbine steam supply branch pipe 27 is connected to the small steam turbine in the plant. The steam inlet end of the heating network branch pipe 28 is connected to the internal turbine steam supply branch pipe 27 through the heating network heater and the small turbine diversion tee 26, and the steam outlet end of the heating network branch pipe 28 is connected to the heating network heater in the plant.

[0045] The internal steam supply branch pipe 27 is connected in series from the steam inlet end to the steam outlet end with the internal steam supply pipeline pneumatic check valve 23, the internal steam supply pipeline pneumatic check valve 24, and the internal steam supply pipeline electric gate valve 25.

[0046] The heating network heater and the small turbine diversion tee 26 is located between the electric gate valve 25 of the internal steam supply pipeline and the small steam turbine in the plant;

[0047] An electric gate valve 30 for the steam supply pipeline of the heating network heater is connected in series on the heating network branch pipeline 28.

[0048] A No. 1 intermediate regulating valve 4 is connected in series on the original hot reheat main pipe 6. The No. 1 intermediate regulating valve 4 is located between the turbine unit and the hot reheat extraction steam tee 7. A No. 2 intermediate regulating valve 5 is connected in parallel on the No. 1 intermediate regulating valve 4. The reheat steam passes through the original hot reheat main pipe 6, the No. 1 intermediate regulating valve 4 and the No. 2 intermediate regulating valve 5 and enters the intermediate pressure cylinder 2.

[0049] The steam supply system also includes a steam replenishment pipeline. The steam inlet end of the steam replenishment pipeline is connected to the hot re-extraction steam pipeline through the No. 3 steam replenishment interface tee 33. The steam outlet end of the steam replenishment pipeline is connected to the internal small turbine steam supply branch pipe 27 through the No. 4 steam replenishment interface tee 32. The steam replenishment pipeline is connected in series with the steam replenishment pipeline electric butterfly valve 16 and the steam replenishment pipeline flow meter 17 from the steam inlet end to the steam outlet end.

[0050] The No. 2 pneumatic quick-closing valve 31 is connected in series on the four-section steam extraction and internal steam supply pipeline. The No. 2 pneumatic quick-closing valve 31 is located between the electric gate valve 25 of the internal steam supply pipeline and the heat network heater and the small unit diversion tee 26.

[0051] This embodiment provides an industrial steam supply system for load reduction and energy saving adjustment, where the lower limit of unit load is limited by high-parameter large-scale steam consumption. Its working principle is similar to that of Specific Embodiment 1, except that the arrangement of the supplementary steam pipeline is different. The design provided in this embodiment adjusts the arrangement of the No. 2 supplementary steam interface tee 18 and the newly added pneumatic quick-closing valve 29 in the steam supply pipeline of the heating network heater in Specific Embodiment 1 when the original external steam supply pipeline is not used for supplementary steam. The No. 2 supplementary steam interface tee 18 is removed and a No. 4 supplementary steam interface tee 32 is added. The newly added pneumatic quick-closing valve 29 in the steam supply pipeline of the heating network heater is removed and a No. 2 pneumatic quick-closing valve 31 is added. The supplementary steam for the original steam-using equipment by the hot re-extraction is connected to the original plant area's four-section extraction steam supply pipeline to the small turbine through the No. 4 supplementary steam interface tee 32. During the heating season, it enters the plant area's heating network heater through the internal small turbine supply branch pipe 27, the heating network heater and small turbine diversion tee 26, the heating network heating branch pipe 28, and the electric gate valve 30 of the heating network heater supply pipeline.

Claims

1. A load-reducing and energy-saving industrial steam supply system for adjusting the lower limit of unit load due to high-parameter large-scale steam consumption, the steam supply system comprising a steam turbine unit, the steam turbine unit comprising a high-pressure cylinder (1), an intermediate-pressure cylinder (2), and a low-pressure cylinder (3), characterized in that: The steam supply system also includes the original hot reheat main pipe (6), hot reheat extraction steam pipeline, four-stage extraction internal steam supply pipeline, four-stage extraction external steam supply pipeline, hot reheat extraction tee (7), and No. 1 interface tee (14). The original hot reheat main pipe (6) is set on the steam inlet end of the intermediate pressure cylinder (2) and connected to the intermediate pressure cylinder (2). The steam outlet end of the original hot reheat main pipe (6) is connected to the turbine unit. The original hot reheat main pipe (6) is equipped with a hot reheat extraction tee (7). The steam inlet end of the hot reheat extraction steam pipeline is connected to the original hot reheat main pipe (6) through the hot reheat extraction tee (7). The four-stage extraction internal steam supply pipeline and the four-stage extraction external steam supply pipeline are connected to the turbine unit. All external steam supply pipelines are set on the extraction end of the intermediate pressure cylinder (2). The steam inlet end of the four-section extraction steam supply pipeline is connected to the extraction end of the intermediate pressure cylinder (2). The steam outlet end of the four-section extraction steam supply pipeline is connected to the small steam turbine and the heater of the plant's heat network. The steam inlet end of the four-section extraction steam supply pipeline is connected to the extraction end of the intermediate pressure cylinder (2). The steam outlet end of the four-section extraction steam supply pipeline is connected to the heat users outside the plant. The four-section extraction steam supply pipeline is equipped with a No. 1 interface tee (14). The steam outlet end of the hot re-extraction steam pipeline is connected to the four-section extraction steam supply pipeline through the No. 1 interface tee (14). The four-section extraction steam supply pipeline includes an internal small turbine steam supply branch pipe (27) and a heating network branch pipe (28). The steam inlet end of the internal small turbine steam supply branch pipe (27) is connected to the extraction end of the intermediate pressure cylinder (2). The steam outlet end of the internal small turbine steam supply branch pipe (27) is connected to the small turbine in the plant. The steam inlet end of the heating network branch pipe (28) is connected to the internal small turbine steam supply branch pipe (27) through the heating network heater and the small turbine diversion tee (26). The steam outlet end of the heating network branch pipe (28) is connected to the heating network heater in the plant. The internal steam supply branch pipe (27) is connected in series from the steam inlet end to the steam outlet end with a first internal steam supply pipeline pneumatic check valve (23), a second internal steam supply pipeline pneumatic check valve (24), and an internal steam supply pipeline electric gate valve (25). The heating network heater and the small turbine diversion tee (26) are located between the electric gate valve (25) of the internal steam supply pipeline and the small steam turbine in the plant; An electric gate valve (30) for the steam supply pipeline of the heating network heater is connected in series on the heating network branch pipeline (28). A No. 1 intermediate regulating valve (4) is connected in series on the original hot reheat main pipe (6). The No. 1 intermediate regulating valve (4) is located between the turbine unit and the hot reheat extraction steam tee (7). A No. 2 intermediate regulating valve (5) is connected in parallel on the No. 1 intermediate regulating valve (4). The reheat steam passes through the original hot reheat main pipe (6), the No. 1 intermediate regulating valve (4), and the No. 2 intermediate regulating valve (5) and enters the intermediate pressure cylinder (2). The hot re-extraction steam pipeline is connected in series from the steam inlet end to the steam outlet end with a pneumatic quick-closing valve (8), a pneumatic check valve (9), an electric gate valve (10), a desuperheating pressure reducer (11), an electric butterfly valve (12), and a hot re-extraction steam flow meter (13). The four-section steam extraction external steam supply pipeline is connected in series from the steam inlet end to the steam outlet end with an electric regulating valve (19), a pneumatic check valve (20), an electric gate valve (21), and a desuperheater (22). The steam supply system also includes a steam replenishment pipeline. The steam inlet end of the steam replenishment pipeline is connected to the external steam supply pipeline of the fourth section through the No. 1 steam replenishment interface tee (15). The steam outlet end of the steam replenishment pipeline is connected to the heating branch pipeline (28) of the heating network through the No. 2 steam replenishment interface tee (18). The steam replenishment pipeline is connected in series with a steam replenishment pipeline electric butterfly valve (16) and a steam replenishment pipeline flow meter (17) from the steam inlet end to the steam outlet end. A new pneumatic quick-connect valve (29) for the steam supply pipeline of the heating network heater is connected in series on the heating network heating branch pipeline (28). The new pneumatic quick-connect valve (29) for the steam supply pipeline of the heating network heater is located between the No. 2 steam injection interface tee (18) and the heating network heater and small machine diversion tee (26). When power generation load and steam supply load are high, the original industrial steam supply method is adopted: After the four-stage extraction steam is drawn from the intermediate pressure cylinder, part of it is supplied internally through the pneumatic check valve (23) of the No. 1 internal steam supply pipeline, the pneumatic check valve (24) of the No. 2 internal steam supply pipeline, and the electric gate valve (25) of the internal steam supply pipeline, ensuring the steam supply for the small turbines and heating network heaters in the plant; the other part is supplied externally through the electric regulating valve (19) of the external steam supply pipeline, the pneumatic check valve (20) of the external steam supply pipeline, the electric gate valve (21) of the external steam supply pipeline, and the desuperheater (22) of the external steam supply pipeline. When the steam supply load is small, the extraction steam method without thermal re-adjustment is used; When the steam consumption is relatively small and the electrical load needs to be appropriately reduced, the steam is drawn out through the hot re-extraction pipeline and successively passes through the No. 1 pneumatic quick-closing valve (8), pneumatic check valve (9), electric gate valve (10), desuperheater and pressure reducer (11), electric butterfly valve (12), hot re-extraction steam flow meter (13), and No. 1 interface tee (14) to connect to the original four-stage extraction steam external supply pipeline. Part of it is supplied to the outside, and the other part is connected to the steam supply pipeline for steam-consuming equipment in the plant through the No. 1 supplementary steam interface tee (15). The supplementary steam passes through the electric butterfly valve (16) of the supplementary steam pipeline. The steam supply pipeline flow meter (17) and the No. 2 steam supply interface tee (18) are connected to the heating network heating branch pipeline (28). During the non-heating season, the electric gate valve (30) of the heating network heater steam supply pipeline is closed. The pneumatic quick pipe valve (29), the heating network heating branch pipeline (28), and the heating network heater and small machine diversion tee (26) are connected to the internal small machine steam supply branch pipeline (27). During the heating season, the valve needs to be opened to supply steam to the plant's internal heating network heater, ensuring the safe and stable operation of the plant's steam-using equipment when the power load is low. The heat re-adjustable steam extraction method is used during low to medium power generation loads and high steam supply loads. Under this operating condition, the newly added No. 1 medium-regulating valve (4) and No. 2 medium-regulating valve (5) are used to coordinate and regulate the steam extraction volume, steam extraction parameters and unit steam inlet parameters, thereby ensuring the heat user's heat safety and the unit's operating safety.

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