A steam turbine heat recovery system capable of achieving turbine-boiler decoupling

Abstract

A steam turbine heat recovery system capable of achieving decoupling of the turbine and boiler comprises a condensate bypass arranged in parallel with the low-pressure heater between the upstream and downstream of the low-pressure heater; a main feedwater bypass is arranged in parallel with the high-pressure heater between the upstream and downstream of the high-pressure heater; the main extraction steam system also comprises a main steam decoupling bypass pipe, part of the high-temperature and high-pressure main steam from the main steam pipe enters the high-pressure cylinder of the steam turbine, and the other part enters the main steam decoupling bypass pipe for decoupling the turbine and boiler; the main steam extraction bypass is led from the main steam decoupling bypass pipe, and after passing through the first desuperheating and pressure reducing device, is connected to the #1 high-pressure heater as a heating steam source; the problem of heat recovery system mismatch during deep decoupling of the turbine and boiler is solved.

Description

Technical Field

[0001] The present invention belongs to the field of flexibility of thermal power plants, and in particular relates to a steam turbine heat recovery system capable of realizing decoupling of a turbine and a boiler. Background Art

[0002] With the implementation of the dual carbon goals, the demand for cogeneration of thermal power units has increased, and the calls for heat and power decoupling and thermal power flexibility have become increasingly louder. Boiler-turbine decoupling technologies are emerging in an endless stream, but when the boiler load rate is significantly different from the turbine load rate, the turbine's heat recovery system cannot operate normally: due to the large amount of water, the amount of extraction steam required for the heat recovery heater is large, but the turbine load is relatively low, which makes the pressure after the extraction stage too low and the pressure difference before and after the blades too large; at the same time, due to the large amount of water, insufficient extraction steam leads to insufficient feed water heating, reduced deoxidation efficiency, and affected the metal life of the heating surface; insufficient extraction steam will also lead to insufficient outlet of the feed water pump; or lead to insufficient feed water temperature, affecting efficiency.

[0003] To sum up, when the load gap between the turbine and boiler is large, the turbine heat recovery system cannot operate normally according to the original design, and the current heat recovery system cannot meet the working conditions of deep decoupling of the turbine and boiler. Summary of the Invention

[0004] The purpose of the present invention is to provide a steam turbine heat recovery system that can achieve deep decoupling of the turbine and boiler.

[0005] A steam turbine heat recovery system capable of achieving turbine-boiler decoupling comprises a return water system and a steam extraction system. The return water system comprises a condensate pump, a condensate main line, a low-pressure heater, a deaerator, a feed water pump, a feed water main line, a high-pressure heater, and a boiler main feed water main pipe; the steam extraction system comprises steam extraction pipes of each section of the steam turbine, connected to the low-pressure heater and the high-pressure heater; the system is characterized in that: a condensate bypass is arranged in parallel with the low-pressure heater between the upstream and downstream of the low-pressure heater; a regulating valve is installed on the condensate bypass, and the regulating valve is used to control the condensate bypass switching and flow rate; and a regulating valve is installed between the upstream and downstream of the high-pressure heater and the high-pressure heater. The main feed water bypass is arranged in parallel with the high-pressure heater; a regulating valve is installed on the main feed water bypass, which is used to control the main feed water bypass switching and adjust the flow; the steam extraction system also includes a main steam decoupling bypass pipe, the main steam decoupling bypass pipe is connected to the main steam pipe, and the main steam pipe is connected to the high-pressure cylinder of the steam turbine; part of the high-temperature and high-pressure main steam from the main steam pipe enters the high-pressure cylinder of the steam turbine, and the other part enters the main steam decoupling bypass pipe for decoupling of the machine and boiler; the main steam extraction bypass is led from the main steam decoupling bypass pipe, and is connected to the No. 1 high-pressure heater as a heating steam source after passing through the first desuperheater and pressure reducer.

[0006] The beneficial effects of this invention are as follows: a bypass is added on the water side to introduce excess water, ensuring that the water volume entering the LP and HP heaters matches the turbine load factor T%. Simultaneously, two extraction steam sources are added to supplement the turbine's extraction steam supply: the main steam decoupling bypass and the high-pressure cylinder exhaust pipe. This ensures that boiler feedwater maintains high parameters while the turbine's existing heat recovery system maintains normal operating conditions, achieving deep boiler-turbine decoupling.

[0007] The present invention is not limited by the cooling method of the unit: whether it is air cooling or water cooling;

[0008] The present invention is not limited by the number of heat recovery stages of the unit;

[0009] The present invention is not limited by the flow direction of the heat network drain of the unit: no matter the heat network drain flows back to the condenser or the deaerator.

[0010] The present invention adopts the idea of ​​"adding a bypass on the water side and adding a steam source on the steam side", so that the heat recovery system can meet the working conditions of deep decoupling of the turbine and boiler.

[0011] This invention solves the problem of "excessive water and insufficient steam" in the heat regeneration system when the load difference between the boiler and turbine is significant. It also eliminates problems such as excessive pressure difference in the extraction stage, insufficient feedwater temperature, and insufficient feedwater pump power. It thus resolves the mismatch problem of the heat regeneration system when the boiler and turbine are deeply decoupled. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 : Schematic diagram of system composition.

[0013] Figure 2 : Schematic diagram of heat recovery system parameters when boiler load rate is 100% and turbine load rate is 50%.

[0014] In the figure: condensate pump (1), condensate main line (2), condensate bypass (3), condensate bypass heater (4), valve (5), pipeline (6), deaerator (7), feed water pump (8), feed water main line (9), main feed water bypass (10), main feed water bypass heater (11), valve (12), outlet main pipe (13), #0 high pressure heater (14), boiler main feed water main pipe (15), first desuperheater (16), second desuperheater (17), main steam extraction bypass (18), pipeline (19), first stage steam extraction valve (20), high pressure cylinder exhaust pipe (21), third desuperheater (22), first branch pipe (23), fourth stage steam supply valve (24), second branch pipe (25), fourth stage steam supply valve (26) DETAILED DESCRIPTION

[0015] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0016] The technical solution of the present invention is not limited by the capacity of the power plant units.

[0017] The technical solution of the present invention is not limited by the deep thermal-electric decoupling and the number of heating units in the power plant.

[0018] The technical solution of the present invention is not limited by the steam parameters of the power plant units.

[0019] The technical solution of the present invention is not limited by the exhaust steam cooling method of power plant units.

[0020] The technical solution of the present invention is not limited by the thermal system of the power plant.

[0021] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0022] like Figure 1 As shown, a steam turbine heat recovery system capable of realizing turbine-boiler decoupling, the turbine-boiler decoupling system includes a main steam pipe, a decoupling bypass pipe, a steam turbine high-pressure cylinder, a boiler reheater, and a hot compressor system;

[0023] The main steam pipe is connected to the decoupling bypass pipe, which is in turn connected to the high-pressure cylinder of the steam turbine. Part of the high-temperature, high-pressure main steam from the main steam pipe enters the high-pressure cylinder of the steam turbine, and the other part enters the decoupling bypass pipe.

[0024] The decoupling bypass pipe is connected to the motive steam inlet of the thermocompressor system, and the high-pressure cylinder exhaust pipe is connected to the suction steam port of the thermocompressor system. A first desuperheater (16) is provided on the decoupling bypass pipe. The steam from the desuperheater bypass pipe is desuperheated and decompressed by the first desuperheater (16) and then used as motive steam for the thermocompressor system; the high-pressure exhaust steam from the high-pressure cylinder exhaust pipe is used as suction steam for the thermocompressor system. The exhaust pipe of the thermocompressor system is connected to the cold end of the reheater.

[0025] The decoupling bypass pipeline is sequentially provided with a regulating valve and a first temperature reducing and pressure reducing device (16). The decoupling bypass pipeline after passing through the first temperature reducing and pressure reducing device (16) is connected to the power steam inlet pipeline of the hot compressor system.

[0026] The heat recovery system includes a return water system and a steam extraction system. The return water system includes a condensate pump (1), a condensate main line (2), a low-pressure heater, a deaerator (7), a feed water pump (8), a feed water main line (9), a high-pressure heater, and a boiler main feed water main pipe (15). The steam extraction sources of the low-pressure heater and the high-pressure heater are both from conventional steam turbine extraction.

[0027] A condensate bypass (3) is arranged between the upstream and downstream of the low-pressure heater and in parallel with the low-pressure heater; a condensate bypass heater (4) and a regulating valve are installed on the condensate bypass (3).

[0028] Condensate is divided into two paths from the outlet main pipe of the condensate pump (1): the main path enters the low-pressure heater for step-by-step heating, and the condensate bypass (3) enters the condensate bypass heater (4), whose outlet is connected to the outlet pipe (6) of the #5 low-pressure heater (before the inlet of the deaerator). The condensate is divided into two paths from the outlet of the condensate pump, one path goes to the conventional low-pressure heater, and the other path enters the condensate bypass heater. After that, the two paths reunite at the #5 low-pressure heater outlet and enter the deaerator together.

[0029] The 4th stage extraction steam of the intermediate pressure cylinder is connected to the condensate bypass heater as a heating source.

[0030] The condensate bypass heater is an optional device, and only the condensate bypass (3) can be set. The condensate bypass (3) is equipped with a corresponding bypass valve, which can be switched on and off and the flow rate can be adjusted according to system requirements.

[0031] A main feed water bypass (10) is arranged in parallel with the high-pressure heater between the upstream and downstream of the high-pressure heater; a main feed water bypass heater (11) and a regulating valve are installed on the main feed water bypass (10).

[0032] The water is divided into two paths from the outlet main pipe of the water pump (8): one path enters the high-pressure heater along the water supply main line (9), and the other path enters the main water supply bypass (10) and the main water supply bypass heater (11), and then merges into the water supply main line (9) at the #1 high-pressure heater outlet main pipe (13).

[0033] The feed water is divided into two paths from the feed water pump outlet, one path goes to the conventional high pressure heater, and the other path enters the feed water bypass heater, and then the two paths of water reunite at the #1 high pressure heater outlet.

[0034] The feedwater bypass heater is an optional device, and only the main feedwater bypass (10) can be set. The main feedwater bypass (10) is equipped with a corresponding bypass valve, which can be switched on and off and the flow rate can be adjusted according to system requirements.

[0035] The decoupled main steam is connected to the main feed water bypass heater as a heating source after being desuperheated and reduced in pressure.

[0036] A #0 high-pressure heater (14) is provided downstream of the #1 high-pressure heater. The feed water enters the #0 high-pressure heater (14) and is heated before entering the boiler economizer through the boiler main feed water main pipe (15).

[0037] Install the #0 HPH heater downstream of the #1 HPH heater to provide supplemental feedwater heating. The #0 HPH heater and the feedwater bypass heater complement each other, and both can be installed. If on-site layout is difficult or cost-constrained, only one or neither can be installed. If neither is installed, switch the steam source of the #1 HPH heater from the first stage extraction steam source to the main steam decoupling bypass to maintain the boiler feedwater temperature.

[0038] The steam extraction system includes a main steam decoupling bypass pipe and a high-pressure cylinder exhaust pipe (21). The main steam decoupling bypass pipe is connected to the hot compressor as power steam for decoupling the turbine and boiler.

[0039] The main steam extraction bypass (18) is connected from the main steam decoupling bypass pipe, and is divided into three routes after passing through the second desuperheater (17): the first route is connected to the #0 high-pressure heater, the second route is connected to the #1 high-pressure heater, and the third route is connected to the feedwater bypass heater as a heating steam source;

[0040] The high-pressure exhaust steam bypass is connected from the high-pressure cylinder exhaust pipe (21), passes through the third temperature and pressure reducer (22), and enters the auxiliary steam header. Then, it is divided into two paths: the first path goes to the deaerator through the first branch pipe (23), and the second path goes to the small steam turbine through the second branch pipe (25).

[0041] The first stage extraction pipe of the high-pressure cylinder is also connected to the #1 high-pressure heater. The steam source of the #1 high-pressure heater can be switched to the first stage extraction steam or the decoupled main steam after temperature reduction and pressure reduction to ensure the boiler feed water temperature. When the decoupled main steam after temperature reduction and pressure reduction is supplied to the #1 high-pressure heater through pipe (19), the original first stage extraction valve (20) must be closed.

[0042] The four-stage steam extraction pipes of the high-pressure cylinder are also connected to the deaerator and the small steam turbine respectively. When the high-pressure exhaust steam is supplied to the deaerator through the first branch pipe (23) after being cooled and reduced in pressure, the original four-stage steam supply valve (24) needs to be closed; when the high-pressure exhaust steam is supplied to the small steam turbine through the second branch pipe (25) after being cooled and reduced in pressure, the original four-stage steam supply valve (26) needs to be closed.

[0043] When the decoupling range between the turbine and boiler is small, the system can be shut down and returned to normal regenerative operation. Alternatively, the water bypass can be disabled, while the system's decoupling steam extraction and / or high-pressure cylinder exhaust steam extraction can be activated. When the decoupling range is small, the water bypass is disabled, the deaerator is heated using four-stage extraction steam, the small steam turbine is driven by high-pressure cylinder exhaust steam, or both are interchanged.

[0044] The system's water circuit consists of a condensate pump, low-pressure heater, condensate bypass heater, deaerator, feedwater pump, high-pressure heater, feedwater bypass heater, #0 HP heater, and boiler economizer. The condensate bypass is drawn from the condensate pump's outlet main pipe, and the condensate bypass heater's outlet is connected to the #5 LP heater's outlet pipe (before the deaerator's inlet). The feedwater bypass heater's inlet is connected to the feedwater pump's outlet pipe, and its outlet is connected to the #1 HP heater's outlet pipe. The #0 HP heater is connected to the downstream main feedwater pipeline of the #1 HP heater, and its outlet enters the boiler economizer.

[0045] The system's steam extraction consists of a main steam decoupling bypass line, a high-pressure cylinder exhaust line, extraction steam piping and valves, and the existing extraction line. After a second desuperheating and pressure reduction, the main steam decoupling bypass line is divided into three directions: Direction 1 goes to the #0 high-pressure heater as heating steam, Direction 2 goes to the #1 high-pressure heater as heating steam, and Direction 3 goes to the feedwater bypass heater as a heating steam source. After desuperheating and pressure reduction, the high-pressure exhaust steam extraction port enters the auxiliary steam header and then goes to the small steam turbine and deaerator.

[0046] Condensate is divided into two main and bypass branches: the main line flows through the existing pipeline into the LP heater at a flow rate Mt corresponding to the turbine load factor T%. Excess condensate flows into the condensate bypass. Because the LP heater water volume is controlled, the steam extraction rate matches the turbine load factor T%. The bypass water is then merged into the main line at the #5 LP heater outlet and enters the deaerator for heating.

[0047] The feedwater is also divided into two branches: a main and a bypass. The main feedwater flows along the existing pipeline to the HPHJ at a flow rate Mt' corresponding to the turbine load factor T%. Excess feedwater flows into the feedwater bypass. Because the HPHJ water flow is controlled, its steam extraction capacity matches the turbine load factor T%. The feedwater bypass finally merges into the main feedwater at the outlet of HPHJ #1. All feedwater is then combined and flows into the #0 HPHJ, and then into the boiler economizer.

[0048] Take the decoupling of the boiler and turbine of a 300MW subcritical unit as an example: when the boiler operates at 100% load, the main feed water volume is 928t, and when the turbine operates at 50% load, the main steam inlet volume is 450t. At this time, after the heat network drain returns to the condenser hot well, the condensate volume is 837t / h, and the contradiction of "more water and less steam" in the heat recovery system is very prominent.

[0049] When this system is put into operation, the condensate pump outlet water volume is divided into two routes: the main route is used to enter the low-temperature heater according to the reheated water volume of 368t / h at the turbine load rate of 50%, and the outlet water temperature of #5 low-temperature heater is the same as the 50% initial condensation condition of the turbine, which is 120℃; the remaining 469 tons of water goes through the bypass and enters the condensate bypass heater. The bypass heater is connected to the four-stage extraction steam and heats the water to 141℃ according to the requirement of 100% boiler load rate. After the two water routes are merged, the mixed temperature is 132℃ and enters the deaerator.

[0050] The 53t / h steam extraction of the deaerator comes from the main steam decoupling bypass. After secondary desuperheating and pressure reduction, the feed water is heated to 163℃ according to the parameters when the boiler load rate is 100% and enters the feed water pump. The ~40t steam source of the feed water pump also comes from the main steam decoupling bypass. Part of the flow of the feed water pump is needed to increase the desuperheating water. The remaining 928t enters the main feed water main pipe and is divided into two routes: 447t enters the original main pipe and passes through the high-temperature heater to heat the feed water to 229℃ according to the turbine load rate of 50%; the remaining 481t enters the feed water bypass heater to heat the feed water to 269℃ according to the boiler load rate of 100%. The combined mixed temperature of the two is 250℃ and enters the boiler economizer.

[0051] In summary, the present invention achieves parameter tuning of the heat regeneration system under decoupled turbine and boiler conditions by adding a bypass on the water side and a steam source on the steam side. This allows high boiler feedwater parameters to be maintained even when the turbine is operating at low load. It also addresses issues such as turbine extraction stage overload, insufficient feedwater temperature, poor deaeration, and feedwater pump output impairment, providing essential support for turbine and boiler decoupling.

[0052] A heat recovery method for a deep boiler decoupling system is as follows:

[0053] 1) Install a bypass at the condensate pump outlet to control the amount of water entering the LP heater, with excess water flowing into the bypass. These two lines reunite at the #5 LP heater outlet and flow into the deaerator. Install a bypass at the feedwater pump outlet to control the amount of water entering the HP heater, with excess water flowing into the bypass. These two lines reunite at the #1 HP heater outlet.

[0054] 2) Install #0 high pressure heater downstream of #1 high pressure heater to supplement the feed water heating and increase the feed water temperature.

[0055] 3) A steam source is drawn from the main steam decoupling bypass, which is desuperheated and depressurized to supply steam to the #0 high-pressure heater and the feedwater bypass heater. It can also serve as a backup steam source for the #1 high-pressure heater. A steam source is drawn from the high-pressure cylinder exhaust pipe, which is desuperheated and depressurized to provide driving steam for the deaerator and small steam turbine.

[0056] 4) Install a flow measurement and control system on the bypass pipeline of condensate and feed water. When the system is put into operation, the water flow in the bypass pipeline is controlled by the bypass valve.

[0057] 5) The steam extraction pipes leading from the main steam decoupling bypass and the high-pressure cylinder exhaust pipe are equipped with a temperature and pressure reducer and a pressure transmitter. The steam pressure entering the heater is controlled by a valve so that the outlet water temperature of the heater meets the requirements of the boiler load rate B%. For example, the outlet water temperature of the feedwater bypass heater needs to be set according to the outlet water temperature of #1 high-pressure heater when the unit load rate is B% under pure condensing conditions; the outlet water temperature of the condensate bypass heater needs to be set according to the outlet water temperature of #5 low-pressure heater when the unit load rate is B% under pure condensing conditions.

[0058] 6) When the decoupling amplitude is low, the boiler load rate B% ​​and the turbine load rate T% are not significantly different. At this time, the gap in the four-stage steam extraction volume is not large, and the steam source of the deaerator and the small steam turbine does not have to be switched to the high-pressure cylinder exhaust. The system can switch the feed water pump to the high-pressure cylinder exhaust according to actual conditions, and the deaerator still uses four-stage steam extraction.

[0059] 7) When the system is put into operation, the steam extraction rate of the fourth stage of the turbine will decrease, causing a slight change in the axial thrust of the high and medium pressure cylinders, but not enough to cause overload. The operating condition of the thrust bearings needs to be monitored. A similar problem occurs when the main steam decoupling bypass is used as the steam source for the #1 high pressure heater. However, this does not cause overload, so the operating condition of the thrust bearings needs to be monitored.

[0060] Finally, it should be noted that the foregoing description is merely an explanation of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail, those skilled in the art will be able to modify the aforementioned technical solutions or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A steam turbine heat recovery system capable of achieving turbine-boiler decoupling, comprising a return water system and a steam extraction system. The return water system includes a condensate pump, a condensate main line, a low-pressure heater, a deaerator, a feed water pump, a feed water main line, a high-pressure heater, and a boiler main feed water main. The steam extraction system includes steam extraction pipes from various sections of the steam turbine, connected to the low-pressure heater and the high-pressure heater. The system is characterized by: A condensate bypass is set up in parallel with the low-pressure heater between the upstream and downstream of the low-pressure heater; a regulating valve is installed on the condensate bypass, and the regulating valve is used to control the condensate bypass switching and adjust the flow; a main feed water bypass is set up in parallel with the high-pressure heater between the upstream and downstream of the high-pressure heater; a regulating valve is installed on the main feed water bypass, and the regulating valve is used to control the main feed water bypass switching and adjust the flow; the steam extraction system also includes a main steam decoupling bypass pipe, the main steam decoupling bypass pipe is connected to the main steam pipe, and the main steam pipe is connected to the high-pressure cylinder of the turbine; part of the high-temperature and high-pressure main steam from the main steam pipe enters the high-pressure cylinder of the turbine, and the other part enters the main steam decoupling bypass pipe for decoupling of the turbine and boiler; the main steam extraction bypass is led from the main steam decoupling bypass pipe, and is connected to the #1 high-pressure heater as a heating steam source after passing through the second desuperheater and pressure reducer.

2. The steam turbine heat recovery system capable of achieving turbine-boiler decoupling according to claim 1, characterized in that: A condensate bypass heater is installed on the condensate bypass. The condensate pump outlet main pipe is divided into two routes: main and bypass. The main route enters the low-pressure heater for step-by-step heating, and the condensate bypass enters the condensate bypass heater, and its outlet is connected to the outlet pipe of the #5 low-pressure heater.

3. The steam turbine heat recovery system capable of achieving turbine-boiler decoupling according to claim 1, characterized in that: A main water supply bypass heater is installed on the main water supply bypass. The outlet main pipe of the water supply pump is divided into two routes. One route enters the high-pressure heater along the water supply main pipeline, and the other route enters the main water supply bypass heater, and then merges into the water supply main pipeline at the #1 high-pressure heater outlet main pipe.

4. The steam turbine heat recovery system capable of achieving turbine-boiler decoupling according to claim 2, characterized in that: The 4th stage extraction steam of the intermediate pressure cylinder is connected to the condensate bypass heater as a heating source.

5. The steam turbine heat recovery system capable of achieving turbine-boiler decoupling according to claim 3, characterized in that: The main steam extraction bypass is connected from the main steam decoupling bypass pipeline, and after passing through the first desuperheater and pressure reducer, it is also connected to the main feed water bypass heater as a heating steam source.

6. The steam turbine heat recovery system capable of achieving turbine-boiler decoupling according to claim 1, characterized in that: The steam extraction system includes a high-pressure cylinder exhaust pipe; the high-pressure exhaust steam bypass is connected from the high-pressure cylinder exhaust pipe, enters the auxiliary steam manifold after passing through the third temperature and pressure reducer, and then is divided into two paths, the first path goes to the deaerator through the first branch pipe, and the second path goes to the small steam turbine through the second branch pipe.

7. The steam turbine heat recovery system capable of achieving turbine-boiler decoupling according to claim 1, characterized in that: The first stage extraction pipe of the high-pressure cylinder is also connected to the #1 high-pressure heater; the steam source of the #1 high-pressure heater adopts the first stage extraction steam or the decoupled main steam after temperature reduction and pressure reduction; when the decoupled main steam supplies steam to the #1 high-pressure heater after temperature reduction and pressure reduction, the original first stage extraction valve needs to be closed.

8. The steam turbine heat recovery system capable of achieving turbine-boiler decoupling according to claim 6, characterized in that: The four-stage steam extraction pipes of the high-pressure cylinder are also connected to the deaerator and the small steam turbine respectively; when the high-exhaust extraction steam is supplied to the deaerator after being cooled and reduced in pressure, the original four-stage steam supply valve needs to be closed; when the high-exhaust extraction steam is supplied to the small steam turbine through the pipeline after being cooled and reduced in pressure, the original four-stage steam supply valve needs to be closed.

9. The steam turbine heat recovery system capable of achieving turbine-boiler decoupling according to claim 1, characterized in that: A #0 high-pressure heater is installed downstream of the #1 high-pressure heater. The feed water enters the #0 high-pressure heater and is heated up before entering the boiler economizer through the boiler main feed water main pipe. The main steam extraction bypass is connected from the main steam decoupling bypass pipe, and after passing through the second desuperheater and pressure reducer, it is also connected to the #0 high-pressure heater as a heating steam source.

10. The steam turbine heat recovery system capable of achieving turbine-boiler decoupling according to claim 1, characterized in that: The main steam decoupling bypass pipe is connected to the power steam inlet of the thermocompressor system, and the high-pressure cylinder exhaust pipe is connected to the suction steam port of the thermocompressor system; a first desuperheater and pressure reducer is provided on the main steam decoupling bypass pipe, and the steam from the main steam decoupling bypass pipe is used as the power steam of the thermocompressor system after being desuperheated and reduced in pressure by the first desuperheater and pressure reducer; the high exhaust steam from the high-pressure cylinder exhaust pipe is used as the suction steam of the thermocompressor system; the exhaust pipe of the thermocompressor system is connected to the cold end of the reheater.

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