Thermal power unit heating system and method

Abstract

A thermal power unit heating system and method includes: main steam generated from a boiler superheater enters a high-pressure bypass heating network heater via a high-pressure bypass heating pipe, heating circulating water from the heating network to cool the main steam and condense it into high-pressure bypass drain; high-pressure bypass drain flowing out of the high-pressure bypass heating network heater enters a heating network drain cooler via a high-pressure bypass heating network heater drain pipe, allowing the high-pressure bypass drain to heat water from the condensate system; and high-pressure bypass drain flowing out of the heating network drain cooler enters a condenser via a heating network drain pipe. The present invention achieves thermoelectric decoupling, directly drawing a heating pipe connected in parallel with the high-pressure bypass pipe from the main steam pipe. The main steam is subjected to two stages of temperature and pressure reduction before being used for heating. When the bypass heating is put into operation, the turbine flow ratio is not changed, thereby "decoupling" the unit operation from the bypass heating. A separate high-pressure bypass heating network heater is configured to prevent the impact of high-pressure bypass heating pressure fluctuations on the intermediate discharge pressure. The control method is simple, and the heating mode is flexible and changeable.

Description

Technical Field

[0001] The present invention relates to the field of thermal power generation units, and in particular to a heating system and method for thermal power generation units. Background Art

[0002] In recent years, the generation of renewable energy sources such as wind power and photovoltaics has increased rapidly. However, the instability and cyclical nature of these power generation sources pose significant challenges to the safe and stable operation of power systems. To accommodate this growing demand for renewable energy, coal-fired power plants have undergone a series of technical upgrades for deep peak-shaving. However, thermal power plants, constrained by their "heat-based electricity" operation, have poor peak-shaving capabilities, leading to significant wind and solar curtailment in regions with a high concentration of cogeneration units.

[0003] Currently, research is underway on a number of thermal-electrical decoupling technologies for cogeneration units, including turbine bypass heating, heat removal from the low-pressure cylinder, hot water and molten salt energy storage, and electric boiler and heat pump heating. Turbine bypass heating has been adopted in many units because it maximizes thermal-electrical decoupling, enabling "shutdown without stopping the boiler." However, this technology also presents numerous challenges. For example, since bypass heating retrofits utilize the unit's existing high- and low-pressure bypasses, this can affect the unit's flow rate distribution. Improper handling can lead to axial thrust imbalance. Commissioning bypass heating requires the high-pressure bypass to be activated. Faulty regulation can result in excessively high high-discharge pressure, causing draft problems in the high-pressure cylinder. Excessive opening of the low-pressure bypass can lead to excessively low recooling pressure, posing a safety risk to the high-pressure cylinder's last-stage blades.

[0004] All of these issues will impact the safe and stable operation of the unit. While bypass heating retrofits have achieved the greatest possible decoupling of heating and power generation, they utilize the unit's existing high- and low-pressure bypass piping, impacting the unit's safe and stable operation and failing to achieve "decoupling" of heating and unit operation. While these issues can be addressed through design optimization and high- and low-pressure bypass logic modifications, the threat to the unit's safe and stable operation remains. Summary of the Invention

[0005] In response to the problems existing in the prior art, the main purpose of the embodiments of the present invention is to provide a heating system and method for a thermal power unit to achieve thermal and electrical decoupling and avoid the impact of high-side heating pressure fluctuations on the middle row pressure.

[0006] To achieve the above-mentioned object, an embodiment of the present invention provides a thermal power unit heating system, comprising: a boiler, a high-pressure bypass heating pipe, a high-pressure bypass heating network heater, a high-pressure bypass heating network heater drain pipe, a heating network drain cooler, a heating network drain pipe, and a condenser;

[0007] The main steam generated from the superheater of the boiler enters the high-pressure bypass heating network heater through the high-pressure bypass heating pipe, heating the circulating water from the heating network to cool the main steam and condense it into high-pressure bypass water;

[0008] The high bypass drain water flowing out of the high bypass heating network heater enters the heating network drain cooler through the high bypass heating network heater drain pipe, so that the high bypass drain water heats the water from the condensate water system;

[0009] The high bypass drain flowing out of the heat network drain cooler enters the condenser through the heat network drain pipe.

[0010] Optionally, in one embodiment of the present invention, a high bypass heating shut-off valve, a high bypass heating regulating valve, a high bypass heating first-stage temperature and pressure reducing device, a high bypass heating second-stage temperature and pressure reducing device and a high bypass heating network heater steam side inlet regulating valve are provided on the high bypass heating pipeline.

[0011] Optionally, in one embodiment of the present invention, the system further includes a high-bypass heating first-level cooling water regulating valve and a high-bypass heating first-level cooling water stop valve; wherein, one end of the high-bypass heating first-level cooling water regulating valve is connected to one end of the high-bypass heating first-level cooling water stop valve, the other end of the high-bypass heating first-level cooling water regulating valve is connected to the high-bypass heating first-level cooling and pressure reducing device, and the other end of the high-bypass heating first-level cooling water stop valve is connected to the water supply system.

[0012] Optionally, in one embodiment of the present invention, the system further comprises a heat recirculation pipe, a medium pressure cylinder, a middle row heat supply pipe, a middle row heat network heater and a middle row heat network heater drain pipe;

[0013] The reheated steam generated from the reheater of the boiler enters the intermediate pressure cylinder through the hot reheat pipe, and the exhaust steam of the intermediate pressure cylinder enters the intermediate exhaust heat network heater through the intermediate exhaust heat supply pipe to heat the circulating water from the heat network, so as to cool the exhaust steam of the intermediate pressure cylinder and condense it into intermediate exhaust water.

[0014] The middle drain water flowing out of the middle drain heat network heater enters the heat network drain cooler through the middle drain heat network heater drain pipe.

[0015] Optionally, in one embodiment of the present invention, a middle row heating check valve, a middle row heating regulating valve and a middle row heating network heater steam side inlet regulating valve are provided on the middle row heating pipe; a middle row heating network heater drain valve is provided on the middle row heating network heater drain pipe.

[0016] Optionally, in one embodiment of the present invention, the system further comprises a heating steam communication pipe, one end of the heating steam communication pipe is connected between the middle row heating regulating valve and the steam side inlet regulating valve of the middle row heating network heater, and the other end is connected between the high bypass heating secondary temperature and pressure reducing device and the steam side inlet regulating valve of the high bypass heating network heater;

[0017] Among them, the heating steam connecting pipeline is provided with a first heating steam connecting stop valve, a heating steam connecting regulating valve and a second heating steam connecting stop valve.

[0018] Optionally, in one embodiment of the present invention, the system also includes a medium- and low-pressure connecting pipe butterfly valve, a medium- and low-pressure connecting pipe bypass valve and a low-pressure cylinder; the medium- and low-pressure connecting pipe butterfly valve is connected in parallel with the medium- and low-pressure connecting pipe bypass valve; wherein, one end of the medium- and low-pressure connecting pipe butterfly valve is connected to the medium-pressure cylinder, and the other end is connected to the low-pressure cylinder.

[0019] Optionally, in one embodiment of the present invention, the system further comprises a drain communication pipe, which is arranged between the middle heat exhaust network heater and the high side heat network heater;

[0020] Among them, the drain communication pipeline is provided with a first drain communication stop valve, a drain communication regulating valve and a second drain communication stop valve.

[0021] Optionally, in one embodiment of the present invention, a high bypass heating network heater drain valve is provided on the high bypass heating network heater drain pipe; a drain-to-condenser stop valve and a drain-to-condenser regulating valve are provided on the heating network drain pipe.

[0022] Optionally, in one embodiment of the present invention, the system further comprises a high-pressure cylinder, a cold recirculation pipe, a high-bypass temperature and pressure reducing device, and a high-bypass regulating valve;

[0023] Among them, the main steam generated from the superheater in the boiler is divided into three paths. The first path enters the high-pressure bypass heating pipe; the second path enters the high-pressure cylinder, and after being discharged from the high-pressure cylinder, enters the reheater in the boiler through the cold reheat pipe; the third path passes through the high-pressure bypass temperature and pressure reducer and the high-bypass regulating valve, and then merges with the main steam discharged from the high-pressure cylinder in the cold reheat pipe and enters the reheater in the boiler.

[0024] An embodiment of the present invention further provides a method for providing heat to a thermal power unit, the method comprising: providing heat by utilizing the heating steam generated by the heating system of the thermal power unit as described above.

[0025] The present invention realizes thermoelectric decoupling, and directly leads out a heating pipeline connected in parallel with the high bypass pipeline from the main steam pipeline. The main steam is used for heating after two-stage temperature and pressure reduction. When the bypass heating is put into operation, the turbine flow ratio is not changed, and the unit operation is "decoupled" from the bypass heating, avoiding the potential threat of existing bypass heating technology to the safe and stable operation of the unit. In addition, a high bypass heating network heater is separately configured to avoid the impact of high bypass heating pressure fluctuations on the middle row pressure. The control method is simple and the heating mode is flexible and changeable. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 The figure is a schematic structural diagram of a heating system for a thermal power unit according to an embodiment of the present invention.

[0028] Explanation of symbols:

[0029] 1- High-pressure bypass heating stop valve; 20- High-pressure bypass heating network heater water side inlet regulating valve;

[0030] 2-High bypass heating regulating valve; 21-Intermediate exhaust heat network heater water side inlet regulating valve;

[0031] 3-high bypass regulating valve; 22-high bypass heating network heater emergency drain valve;

[0032] 4- High bypass heating first-stage desuperheater and pressure reducer; 23- Middle exhaust heat network heater emergency drain valve;

[0033] 5-High bypass temperature and pressure reducer; 24-High bypass heating network heater steam trap;

[0034] 6- High bypass heating first-stage desuperheating water regulating valve; 25- Middle exhaust heat network heater drain valve;

[0035] 7-High bypass desuperheating water regulating valve; 26-Middle row heating check valve;

[0036] 8-High bypass heating first-stage desuperheating water stop valve; 27-Middle row heating regulating valve;

[0037] 9-High bypass desuperheating water stop valve; 28-Intermediate exhaust heat network heater steam side inlet regulating valve;

[0038] 10-High bypass heating two-stage desuperheater and pressure reducer; 29-Medium and low pressure connecting pipe bypass valve;

[0039] 11-First heating steam connection stop valve; 30-Medium and low pressure connecting pipe butterfly valve;

[0040] 12-heating steam connecting regulating valve; 31-low bypass regulating valve;

[0041] 13-Second heating steam connection stop valve; 32-Low bypass desuperheating water stop valve;

[0042] 14- High bypass heating network heater steam side inlet regulating valve; 33- Low bypass desuperheating water regulating valve;

[0043] 15-High bypass heating network heater water side outlet regulating valve; 34-Low bypass desuperheater and pressure reducer;

[0044] 16-water outlet regulating valve of the middle heat exhaust network heater; 35-water drain to condenser stop valve;

[0045] 17-First drain connection stop valve; 36-Drain to condenser regulating valve;

[0046] 18-drainage communication regulating valve; 37-high bypass heating secondary desuperheating water stop valve;

[0047] 19-The second drain connection stop valve; 38-The high bypass heating secondary desuperheating water regulating valve. DETAILED DESCRIPTION

[0048] The embodiments of the present invention provide a thermal power unit heat supply system and method.

[0049] 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. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0050] like Figure 1 FIG2 is a schematic diagram of the structure of a thermal power unit heating system according to an embodiment of the present invention. The system shown in the figure includes: a boiler, a high-pressure bypass heating pipe, a high-pressure bypass heating network heater, a high-pressure bypass heating network heater drain pipe, a heating network drain cooler, a heating network drain pipe, and a condenser.

[0051] The main steam generated from the superheater of the boiler enters the high-pressure bypass heating network heater through the high-pressure bypass heating pipe, heating the circulating water from the heating network to cool the main steam and condense it into high-pressure bypass water;

[0052] The high bypass drain water flowing out of the high bypass heating network heater enters the heating network drain cooler through the high bypass heating network heater drain pipe, so that the high bypass drain water heats the water from the condensate water system;

[0053] The high bypass drain flowing out of the heat network drain cooler enters the condenser through the heat network drain pipe.

[0054] As an embodiment of the present invention, the high bypass heating pipeline is provided with a high bypass heating stop valve 1, a high bypass heating regulating valve 2, a high bypass heating first-level temperature and pressure reducing device 4, a high bypass heating second-level temperature and pressure reducing device 10 and a high bypass heating network heater steam side inlet regulating valve 14.

[0055] In this embodiment, the system also includes a high-side heating first-level cooling water regulating valve 6 and a high-side heating first-level cooling water stop valve 8; wherein, one end of the high-side heating first-level cooling water regulating valve 6 is connected to one end of the high-side heating first-level cooling water stop valve 8, the other end of the high-side heating first-level cooling water regulating valve 6 is connected to the high-side heating first-level cooling and pressure reducing device 4, and the other end of the high-side heating first-level cooling water stop valve 8 is connected to the water supply system.

[0056] In this embodiment, the system further includes a hot reheat pipe, a medium pressure cylinder, a middle row heating pipe, a middle row heat network heater, and a middle row heat network heater drain pipe;

[0057] Among them, the reheated steam generated from the boiler reheater enters the intermediate pressure cylinder through the hot reheat pipe, and the exhaust steam of the intermediate pressure cylinder enters the intermediate exhaust heat network heater through the intermediate exhaust heat supply pipe to heat the circulating water from the heat network, so that the exhaust steam of the intermediate pressure cylinder is cooled and condensed into intermediate exhaust water;

[0058] The middle drain water flowing out of the middle drain heat network heater enters the heat network drain cooler through the middle drain heat network heater drain pipe.

[0059] In this embodiment, a middle row heating check valve 26, a middle row heating regulating valve 27 and a middle row heating network heater steam side inlet regulating valve 28 are provided on the middle row heating network heater drain pipe; a middle row heating network heater drain valve 25 is provided on the middle row heating network heater drain pipe.

[0060] In this embodiment, the system further includes a heating steam communication pipe, one end of which is connected between the middle row heating regulating valve and the middle row heating network heater steam side inlet regulating valve 28, and the other end is connected between the high bypass heating secondary temperature and pressure reduction device 10 and the high bypass heating network heater steam side inlet regulating valve 14;

[0061] Among them, the heating steam connecting pipeline is provided with a first heating steam connecting stop valve 11, a heating steam connecting regulating valve 12 and a second heating steam connecting stop valve 13.

[0062] In this embodiment, the system also includes a medium- and low-pressure connecting pipe butterfly valve 30, a medium- and low-pressure connecting pipe bypass valve 29 and a low-pressure cylinder; the medium- and low-pressure connecting pipe butterfly valve 30 is connected in parallel with the medium- and low-pressure connecting pipe bypass valve 29; wherein, one end of the medium- and low-pressure connecting pipe butterfly valve 30 is connected to the medium-pressure cylinder, and the other end is connected to the low-pressure cylinder.

[0063] In this embodiment, the system further includes a drain communication pipe, which is arranged between the middle heat exhaust network heater and the high side heat network heater;

[0064] Among them, the drain communication pipeline is provided with a first drain communication stop valve 17, a drain communication regulating valve 18 and a second drain communication stop valve 19.

[0065] As an embodiment of the present invention, a high bypass heating network heater drain valve is provided on the high bypass heating network heater drain pipe; a drain-to-condenser stop valve and a drain-to-condenser regulating valve are provided on the heating network drain pipe.

[0066] As an embodiment of the present invention, the system further includes a high-pressure cylinder, a cold recirculation pipe, a high-bypass temperature and pressure reducing device 5 and a high-bypass regulating valve 3;

[0067] Among them, the main steam generated from the superheater in the boiler is divided into three paths. The first path enters the high-pressure bypass heating pipe; the second path enters the high-pressure cylinder, and after being discharged from the high-pressure cylinder, enters the reheater in the boiler through the cold reheat pipe; the third path passes through the high-pressure bypass temperature and pressure reducer 5 and the high-pressure bypass regulating valve 3, and then merges with the main steam discharged from the high-pressure cylinder in the cold reheat pipe and enters the reheater in the boiler.

[0068] The embodiment of the present invention provides a thermal power unit heating system and operation method suitable for deep peak regulation. Figure 1 The system shown here includes two heating steam circuits: one is main steam, which is desuperheated and decompressed, and the other is exhaust steam from the intermediate-pressure cylinders. A connecting pipe heating bypass valve is provided to allow operation without the low-pressure cylinders. Depending on the unit's operating mode and heating requirements, these two heating methods can be interconnected or operate independently without affecting each other.

[0069] Compared with the currently used bypass heating reconstruction technology, the present invention can also achieve thermal and electrical decoupling to the greatest extent, and does not use the original high- and low-pressure bypass pipes of the unit, but directly leads out the heating pipe connected in parallel with the high bypass pipe from the main steam pipe. The main steam is used for heating after two-stage temperature and pressure reduction. When the bypass heating is put into operation, the turbine flow ratio is not changed, and the unit operation is "decoupled" from the bypass heating, avoiding the potential threat posed by the existing bypass heating technology to the safe and stable operation of the unit. In addition, a high-bypass heating network heater is separately configured. When the unit is operated in the low-pressure cylinder cut-off mode, the connection between the high-bypass heating and the middle-row heating can be disconnected to avoid the impact of high-bypass heating pressure fluctuations on the middle-row pressure. The control method is simple and the heating mode is flexible and changeable.

[0070] In this embodiment, if Figure 1 As shown, the main process of the system of the present invention is described in detail as follows:

[0071] The main steam generated from the boiler superheater is divided into three routes: one enters the high-pressure cylinder, one enters the cold recirculation pipe through the high-pressure bypass control valve 3 and the desuperheater and pressure reducer 5, and one enters the high-pressure bypass heating pipe connected to the high-pressure bypass pipe. The following describes these three processes separately.

[0072] 1. After the main steam enters the high-pressure cylinder, it performs work externally inside the high-pressure cylinder, and the temperature and pressure decrease. It is then discharged into the cold reheat pipe and enters the boiler reheater for heating.

[0073] 2. The main steam entering the high-pressure bypass passes through the high-pressure bypass desuperheater and pressure reducer 5, where its temperature and pressure are reduced. It then enters the cold reheat pipe, where it merges with the steam discharged from the high-pressure cylinder and enters the boiler reheater for heating. It should be noted that the high-pressure bypass is only used for turbine startup. After the unit is connected to the grid for power generation, the high-pressure bypass control valve 3 is closed.

[0074] 3. The main process of main steam for heating is described as follows:

[0075] The main steam enters the high-pressure bypass heating network heater through the high-pressure bypass heating pipe, which is equipped with a high-pressure bypass heating stop valve 1, a high-pressure bypass heating regulating valve 2, a high-pressure bypass heating primary desuperheater and pressure reducer 4, a high-pressure bypass heating secondary desuperheater and pressure reducer 10, and a high-pressure bypass heating network heater steam-side inlet regulating valve 14. The steam heats the circulating water from the heating network, lowering the steam temperature and condensing it into drain water. The drain water then flows through the high-pressure bypass heating network heater drain pipe and the high-pressure bypass heating network heater drain valve 24 installed thereon, into the heating network drain cooler. After heating the condensate system water, the drain water is discharged into the condenser through the heating network drain pipe. The heat network drain pipe is equipped with a drain-to-condenser stop valve 35 and a drain-to-condenser regulating valve 36.

[0076] The above-mentioned high bypass heating first-level desuperheating water comes from the water supply system, on which are arranged the high bypass heating first-level desuperheating water regulating valve 6 and the high bypass heating first-level desuperheating water stop valve 8; the high bypass heating second-level desuperheating water comes from the middle tap of the water supply pump or the condensate water system, on which are arranged the high bypass heating second-level desuperheating water regulating valve 38 and the high bypass heating second-level desuperheating water stop valve 37.

[0077] 2. Steam discharged from the high-pressure bypass and high-pressure cylinder enters the reheater for heating and then flows through the hot reheat pipe, where it is split into two paths: one entering the intermediate-pressure cylinder and the other entering the low-pressure bypass pipe. The steam then flows through the low-pressure bypass regulating valve 31 and the low-pressure bypass desuperheater and pressure reducer 34 and is discharged into the condenser. The low-pressure bypass desuperheating water is derived from condensate, and the desuperheating water pipe is equipped with a low-pressure bypass desuperheating water stop valve 32 and a low-pressure bypass desuperheating water regulating valve 33.

[0078] 3. The steam entering the intermediate pressure cylinder performs work inside the intermediate pressure cylinder. After the temperature and pressure drop, it is discharged from the intermediate pressure cylinder and divided into two paths. One path enters the low pressure cylinder through the intermediate and low pressure connecting pipe to perform work and finally enter the condenser; the other path enters the intermediate discharge heating pipe to provide heat. The following is a detailed introduction to the intermediate discharge heating process:

[0079] The exhaust steam from the intermediate pressure cylinder enters the intermediate heat supply pipe, passing through the intermediate heat supply check valve 26, the intermediate heat supply regulating valve 27, and the intermediate heat supply network heater steam inlet regulating valve 28. It then enters the intermediate heat supply network heater, heating the circulating water from the heat supply network. This lowers the steam temperature and condenses it into drain water. The drain water then passes through the intermediate heat supply network heater drain pipe and the intermediate heat supply network heater drain valve 25 located thereon, and enters the heat supply network drain cooler to heat the condensate before being discharged through the heat supply network drain pipe into the condenser.

[0080] The intermediate and low-pressure connecting pipes are equipped with intermediate and low-pressure connecting pipe butterfly valves 30 and intermediate and low-pressure connecting pipe bypass valves 29. When the intermediate exhaust heat supply is high, the intermediate exhaust pressure is maintained by closing the intermediate and low-pressure connecting pipe butterfly valves 30. The low-pressure cylinder is shut off by closing the intermediate and low-pressure connecting pipe butterfly valves 30 and opening the intermediate and low-pressure connecting pipe bypass valves 29.

[0081] The present invention is also designed with a heating steam connecting pipeline, which can realize the connection between the high bypass heating steam and the middle row heating steam. The first heating steam connecting stop valve 11, the heating steam connecting regulating valve 12 and the second heating steam connecting stop valve 13 are arranged on the pipeline.

[0082] A drain communication pipeline is also designed, on which a first drain communication stop valve 17, a drain communication regulating valve 18, and a second drain communication stop valve 19 are arranged.

[0083] In order to prevent the water level in the high bypass heating network heater and the middle exhaust heating network heater from being too high, emergency drainage pipes are also designed. The pipes are designed with an emergency drainage valve 22 for the high bypass heating network heater and an emergency drain valve 23 for the middle exhaust heating network heater.

[0084] 1. Since the middle exhaust heating and the operation with the low-pressure cylinder removed only achieve thermal and electrical decoupling to a certain extent, when the unit is operated with the low-pressure cylinder removed, the middle exhaust heating cannot meet the external heat load requirements and the heat load cannot be increased by increasing the steam inlet to the turbine, high-pressure bypass heating is required to meet the external requirements for the unit's electrical load and heating load at the same time.

[0085] 2. The unit gives priority to using the middle row for heating, because although high-side heating achieves thermal and electrical decoupling to the greatest extent, high-side heating uses high-quality heat sources for heating, which is less economical.

[0086] 3. When the unit is running with the low-pressure cylinder cut off and the high-pressure bypass heating is put into operation, because only the bypass of the medium- and low-pressure connecting pipes is open at this time, the pipe diameter is small and only provides cooling flow for the low-pressure cylinder. If the high-pressure bypass heating is connected to the medium-pressure exhaust heating, then the medium-pressure cylinder exhaust pressure (medium-pressure exhaust pressure) is greatly affected by the high-pressure bypass heating pressure. At this time, the valve on the heating connecting pipe should be closed to make the high-pressure bypass heating and the medium-pressure exhaust heating operate independently to prevent the high-pressure bypass heating pressure fluctuation from causing a sudden increase in the medium-pressure exhaust pressure, affecting the safe and stable operation of the unit.

[0087] Compared with the existing bypass heating modification technology, the present invention does not utilize the original high and low bypass pipes of the unit. Instead, a heating pipe connected in parallel with the high bypass pipe is directly drawn out from the main steam pipe, and the heating is performed after the temperature and pressure are reduced, so that the high bypass heating is completely independent of the operation of the unit, and thermoelectric decoupling is achieved to the greatest extent, thus avoiding the potential threats to the safe and stable operation of the unit caused by the existing technology, such as axial thrust imbalance, high-pressure cylinder blasting, and increased force on the last-stage blades of the high-pressure cylinder. The high bypass heating and the middle row heating can be interconnected and operated independently, with a flexible heating method, which improves the heating capacity of the unit. When the equipment fails and the middle row heating cannot be put into use, the high bypass heating can be used, thereby improving the heating stability of the unit. The control method is simple, and there is no need to modify the logic of the original high and low bypass control valves.

[0088] An embodiment of the present invention further provides a method for providing heat to a thermal power unit, the method comprising: providing heat by utilizing the heating steam generated by the heating system of the thermal power unit as described above.

[0089] Based on the same application concept as the aforementioned thermal power unit heating system, the present invention also provides the aforementioned thermal power unit heating method. Because the principles underlying the thermal power unit heating method are similar to those of the thermal power unit heating system, the implementation of the thermal power unit heating method can be referenced to the implementation of the thermal power unit heating system, and any repetitions will not be repeated.

[0090] The present invention realizes thermoelectric decoupling, and directly leads out a heating pipeline connected in parallel with the high bypass pipeline from the main steam pipeline. The main steam is used for heating after two-stage temperature and pressure reduction. When the bypass heating is put into operation, the turbine flow ratio is not changed, and the unit operation is "decoupled" from the bypass heating, avoiding the potential threat of existing bypass heating technology to the safe and stable operation of the unit. In addition, a high bypass heating network heater is separately configured to avoid the impact of high bypass heating pressure fluctuations on the middle row pressure. The control method is simple and the heating mode is flexible and changeable.

[0091] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0092] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0093] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0094] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0095] Specific embodiments are used in the present invention to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas. At the same time, for those skilled in the art, according to the ideas of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A thermal power unit heating system, characterized in that: The system includes: a boiler, a high-pressure bypass heating pipe, a high-pressure bypass heating network heater, a high-pressure bypass heating network heater drain pipe, a heating network drain cooler, a heating network drain pipe and a condenser; The main steam generated from the superheater in the boiler enters the high bypass heating network heater through the high bypass heating pipe to heat the circulating water from the heating network, so that the main steam is cooled and condensed into high bypass water; The high bypass drain water flowing out of the high bypass heating network heater enters the heating network drain cooler through the high bypass heating network heater drain pipe, so that the high bypass drain water heats the condensate water system water; The high bypass drain water flowing out from the heat network drain cooler enters the condenser through the heat network drain pipe; The high bypass heating pipe is connected in parallel with the high bypass pipe; the system includes two heating steam lines and heating steam communication pipes, one of which is the main steam that is desuperheated and decompressed for heating; the other is the exhaust steam from the intermediate pressure cylinder for heating, wherein the intermediate and low pressure connecting pipes are provided with intermediate and low pressure connecting pipe butterfly valves and intermediate and low pressure connecting pipe bypass valves. When the intermediate exhaust heat supply is large, the intermediate exhaust pressure is maintained by closing the intermediate and low pressure connecting pipe butterfly valves; the low pressure cylinder operation is cut off by closing the intermediate and low pressure connecting pipe butterfly valves and opening the intermediate and low pressure connecting pipe bypass valves. Wherein, the high bypass heating pipeline is provided with a high bypass heating secondary temperature and pressure reduction device and a high bypass heating network heater steam side inlet regulating valve; the middle row heating pipeline is provided with the middle row heating regulating valve and the middle row heating network heater steam side inlet regulating valve; one end of the heating steam connecting pipeline is connected between the middle row heating regulating valve and the middle row heating network heater steam side inlet regulating valve, and the other end is connected between the high bypass heating secondary temperature and pressure reduction device and the high bypass heating network heater steam side inlet regulating valve; Wherein, the heating steam connecting pipeline is provided with a first heating steam connecting stop valve, a heating steam connecting regulating valve and a second heating steam connecting stop valve.

2. The system according to claim 1, wherein: The high bypass heating pipeline is also provided with a high bypass heating stop valve, a high bypass heating regulating valve and a high bypass heating first-level temperature and pressure reducing device.

3. The system according to claim 2, characterized in that The system also includes a high-side heating first-level cooling water regulating valve and a high-side heating first-level cooling water stop valve; wherein, one end of the high-side heating first-level cooling water regulating valve is connected to one end of the high-side heating first-level cooling water stop valve, the other end of the high-side heating first-level cooling water regulating valve is connected to the high-side heating first-level cooling and pressure reducing device, and the other end of the high-side heating first-level cooling water stop valve is connected to the water supply system.

4. The system according to claim 2, wherein: The system also includes a heat recirculation pipe, a medium pressure cylinder, a middle row heating pipe, a middle row heat network heater and a middle row heat network heater drain pipe; The reheated steam generated from the reheater of the boiler enters the intermediate pressure cylinder via the hot reheat pipe, and the exhaust steam of the intermediate pressure cylinder enters the intermediate exhaust heat network heater via the intermediate exhaust heat supply pipe to heat the circulating water from the heat network, so as to cool the exhaust steam of the intermediate pressure cylinder and condense it into intermediate exhaust water. The middle drain water flowing out of the middle drain heat network heater enters the heat network drain cooler through the middle drain heat network heater drain pipe.

5. The system according to claim 4, characterized in that The middle row heating pipe is also provided with a middle row heating check valve; the middle row heating network heater drain pipe is provided with a middle row heating network heater drain valve.

6. The system according to claim 4, characterized in that The system also includes a medium- and low-pressure connecting pipe butterfly valve, a medium- and low-pressure connecting pipe bypass valve and a low-pressure cylinder; the medium- and low-pressure connecting pipe butterfly valve is connected in parallel with the medium- and low-pressure connecting pipe bypass valve; wherein one end of the medium- and low-pressure connecting pipe butterfly valve is connected to the medium-pressure cylinder, and the other end is connected to the low-pressure cylinder.

7. The system according to claim 4, wherein: The system further comprises a drain communication pipe, which is arranged between the middle heat exhaust network heater and the high bypass heat network heater; Wherein, the drain communication pipeline is provided with a first drain communication stop valve, a drain communication regulating valve and a second drain communication stop valve.

8. The system according to claim 1, wherein: The high bypass heating network heater drain pipe is provided with a high bypass heating network heater drain valve; the heating network drain pipe is provided with a drain-to-condenser stop valve and a drain-to-condenser regulating valve.

9. The system according to claim 1, wherein: The system also includes a high-pressure cylinder, a cold recirculation pipe, a high-bypass temperature and pressure reducer, and a high-bypass regulating valve; Among them, the main steam generated from the superheater in the boiler is divided into three paths. The first path enters the high-pressure bypass heating pipe; the second path enters the high-pressure cylinder, and after being discharged from the high-pressure cylinder, enters the reheater in the boiler through the cold reheat pipe; the third path passes through the high-pressure bypass temperature and pressure reducing device and the high-pressure bypass regulating valve, and then merges with the main steam discharged from the high-pressure cylinder through the cold reheat pipe and enters the reheater in the boiler.

10. A method for providing heat to a thermal power unit, characterized in that: The method comprises: utilizing the heating steam generated by the thermal power unit heating system according to any one of claims 1 to 9 to provide heat.

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