A heating system of a coal-fired power unit coupled with a heat pump

Abstract

The present invention relates to the field of power generation technology, and in particular to a heating system for a coal-fired power unit coupled with a heat pump. Currently, coal-fired power generation cannot meet the centralized heating needs of the power grid under different load conditions. Conventional transformation lines are numerous, costly, and prone to problems. To this end, the present invention provides a heating system for a coal-fired power unit coupled with a heat pump, comprising a steam device with a cylinder and a steam pipeline, a heat exchange device with a heat exchanger, and a heating device with a heating pipeline and a return water pipeline. The heating pipeline and the steam pipeline are connected to the heat exchange device for heat exchange, the outlet of the heating pipeline is connected to the heating area, and the inlet of the return water pipeline is connected to the heating area to recover hot water and return it to the heating pipeline for recycling. The heating system also includes a heat pump device with an absorption heat pump, a condenser, and a cooling tower. The present invention couples a heat pump into the heating system to improve the utilization rate of hot steam and reduce losses. The present invention can respectively select a heat pump device and a heat exchange device to heat water under both normal load and peak load conditions of the unit to reduce steam waste.

Description

Technical Field

[0001] The present invention relates to the technical field of power generation, in particular to a heating system of a coal-fired power unit coupled with a heat pump. Background Art

[0002] Thermal power plants are a key component of industrial energy conservation. Retrofitting centralized heating systems with thermal power plants can help reduce energy consumption and improve energy utilization. However, because thermal power plants also need to meet the grid's deep peak-shaving requirements, retrofitting these plants for centralized heating would be costly and complex. Furthermore, the resulting system is overly complex, prone to operational issues, and lacks stability. Currently, there is a lack of a heating system in the coal-fired power generation sector that can effectively integrate heating with coal-fired power plants, meet the grid's deep peak-shaving requirements, provide centralized heating, and offer simplified wiring modifications, reducing energy consumption and improving efficiency. Summary of the Invention

[0003] The technical problems to be solved and the technical tasks proposed by the present invention are aimed at the lack of integration of heating and coal-fired power units in the existing thermal power generation field, the technical problems of numerous lines, high costs, easy problems in later operation, and poor stability. The present invention provides a heating system for coal-fired power units coupled with heat pumps. The system couples the heat pump with the cylinder of the thermal power generation coal-fired power unit, improves the utilization rate of hot steam in the condenser, reduces losses and improves efficiency, and can adopt flexible heating methods according to the peak-shaving conditions to ensure that the unit meets the peak-shaving application of the power grid and reduces steam waste.

[0004] The technical solution adopted by the present invention to solve the technical problem is as follows: a heating system of a coal-fired power unit coupled with a heat pump, comprising a steam device with a cylinder and a steam pipeline, a heat exchange device with a heat exchanger, and a heating device with a heating pipeline and a return water pipeline. The heating pipeline and the steam pipeline are connected to the heat exchange device for heat exchange. The outlet of the heating pipeline is connected to the heating area, and the inlet of the return water pipeline is connected to the heating area to recover hot water and send it back to the heating pipeline for recycling. The heating system is characterized in that it also includes a heat pump device with an absorption heat pump, a condenser and a cooling tower. The cylinder is connected to the condenser and the absorption heat pump through the steam pipeline output. The heat medium inlet of the heat pump and the condenser are connected to the cooling tower via a circulating cooling water pipeline. A circulating water pump is provided on the cooling water pipeline. The cooling water pipeline is divided into two branches before entering the cooling tower to connect to the heat medium inlet and outlet of the absorption heat pump. The absorption heat pump is connected to an exhaust pipe to discharge the steam after heat exchange. A bypass is branched from the return water pipeline to connect to the heat supply pipeline connected to the absorption heat pump. The bypass is provided with a return water bypass valve. The return water pipeline outlet is connected to the cold medium inlet of the absorption heat pump and is provided with a heat pump inlet valve. The heat supply pipeline inlet is connected to the cold medium outlet of the absorption heat pump and is provided with a heat pump outlet valve. The present invention adds a heat pump device to the existing steam heat exchange heating structure, further improving the hot steam utilization rate of the condenser, reducing steam loss and improving efficiency. The system can choose to use either the heat exchange device or the heat pump device to provide hot water under different working conditions. The absorption heat pump can use steam as a driving heat source to provide hot water, thereby increasing the efficiency of thermal energy utilization. When the coal-fired power unit is operating at normal load, a heat pump device is used to provide hot water. Steam is fed into the absorption heat pump in two ways: directly through the steam pipeline, and first into the condenser and then through a branch pipe extending from the cooling water pipeline to provide the driving heat source. When the coal-fired power unit is operating at peak load, the absorption heat pump does not participate in the heat supply. Simply closing the heat pump inlet and outlet valves can prevent water from flowing into the heat pump. The water in the return pipe flows back to the heating pipeline through a bypass, not passing through the absorption heat pump. The system then heats the water by sending steam into the heat exchanger. Two branches on the cooling water pipeline connect to the absorption heat pump to feed the condensate treated by the condenser into the absorption heat pump for reuse. After use, it is returned to the cooling water pipeline for circulation. The function of the circulating water pump is to ensure the circulation of water in the cooling water pipeline.

[0005] As a further improvement and supplement to the above technical solution, the present invention adopts the following technical measures: the cylinder includes a medium-pressure cylinder and a low-pressure cylinder connected by pipelines, the steam device also includes a steam cylinder, the medium-pressure cylinder is connected to two steam pipelines connected to the condenser and the steam cylinder respectively, a steam inlet stop valve is provided on the steam pipeline connected to the steam cylinder output from the medium-pressure cylinder, a second bypass steam pipe is branched out on the pipeline connected to the medium-pressure cylinder to connect to the heat medium inlet of the absorption heat pump, and a steam pipeline is connected to the low-pressure cylinder to connect the condenser; the heat exchange device includes a steam-water heat exchanger, a water-water heat exchanger and a recovery water tank connected in series from front to back through the steam pipeline, a steam pipe is connected between the steam-water heat exchanger and the steam cylinder and a steam outlet stop valve is provided, and the recovery water tank is connected to the condenser through the pipeline output. The steam cylinder consists of two cylinders, medium-pressure and low-pressure cylinders. Each cylinder has a steam pipeline output to the condenser. At the same time, the two cylinders are also connected by a pipeline. The steam output from the medium-pressure cylinder can be sent to the low-pressure cylinder to continue working. The steam cylinder can collect and store steam and adjust the steam pressure to ensure that the steam pressure is within a stable range and the amount of steam for heat exchange. At the same time, a stop valve is set on the inlet and outlet pipelines of the steam cylinder to control the steam in and out of the steam cylinder. The heat exchanger of the heat exchange device includes a steam-water exchanger connected in series along the steam supply direction. The two heat exchangers use the heat source in the same pipeline to heat the cold medium passing through the heat exchanger in sequence. The steam sent from the steam cylinder first enters the steam-water heat exchanger in the form of steam for heat exchange. After the heat exchange, the steam cools down and becomes water and then enters the water-water heat exchanger for heat exchange again. Both heat exchangers can heat the cold medium water flowing through it. The cold medium water flows through the water-water heat exchanger and the steam-water heat exchanger in turn to be heated; the water and steam coming out of the water-water heat exchanger are sent to the recovery water tank, and the water in the recovery water tank can be sent to the condenser for recycling.

[0006] The steam pipeline connecting the steam-water heat exchanger and the water-water heat exchanger is equipped with a steam-water heat exchanger drain valve, while the steam pipeline connecting the water-water heat exchanger and the recovery water tank is equipped with a water-water heat exchanger drain valve. Both drain valves automatically block steam and drain water, allowing water to flow through the pipeline while simultaneously converting steam within the pipeline into condensate and discharging it outside the pipeline. These two drain valves regulate the water flow for heat exchange.

[0007] The steam pipeline connecting the steam cylinder and the steam-water heat exchanger is provided with a stop valve in front of the steam-water heat exchanger electric valve, a steam-water heat exchanger electric valve and a stop valve behind the steam-water heat exchanger electric valve in sequence along the steam forward direction on one side of the steam-water heat exchanger. A parallel steam bypass pipe is forked out from the steam pipeline, and a steam-water heat exchanger bypass valve is provided on the steam bypass pipe. One end of the steam bypass pipe is connected to the steam pipeline between the steam outlet stop valve and the stop valve in front of the steam-water heat exchanger electric valve, and the other end is connected to the steam pipeline between the stop valve behind the steam-water heat exchanger electric valve and the steam-water heat exchanger. The steam output from the steam cylinder to the steam-water heat exchanger can be divided into two paths during its journey. When the steam volume is not large, the steam-water heat exchanger bypass valve is closed, the steam bypass pipe is in a closed state, and the steam can only be sent into the steam-water heat exchanger along the steam pipeline. The steam-water heat exchanger electric valve can adjust the steam volume, and the front and rear stop valves are used to cut off the throttling opening and closing passage; when the steam volume is too large, the steam-water heat exchanger bypass valve is opened, and the steam bypass pipe is also in an open state to divert part of the steam.

[0008] The pipeline connecting the recovery water tank to the condenser is equipped with a condensate pump inlet stop valve, a condensate pump, and a condensate pump outlet check valve in sequence from the recovery water tank side to the condenser side. Water in the recovery water tank can be pumped into the condenser by the condensate pump for recycling. The condensate pump inlet stop valve is used to cut off the water flow, and the condensate pump outlet check valve is used to prevent water backflow.

[0009] The branch pipe connecting to the absorption heat pump's heat medium inlet is equipped with a heat pump inlet valve and a booster pump, with the booster pump located on one side of the absorption heat pump. The branch pipe connecting to the absorption heat pump's heat medium outlet is equipped with a heat pump outlet valve. The booster pump boosts the pressure of water in the cooling water pipeline and delivers it to the absorption heat pump. Both the heat pump inlet valve and the heat pump outlet valve can cut off the water flow in their respective pipelines.

[0010] A water distributor is installed on the heating pipeline between the steam-water heat exchanger and the heating zone. A heating booster pump inlet valve, a heating booster pump, and a heating booster pump outlet valve are sequentially arranged along the direction of hot water flow. A steam-water heat exchanger outlet electric valve is installed on the heating pipeline between the water distributor and the steam-water heat exchanger, and a water-to-water heat exchanger outlet electric valve is installed on the heating pipeline between the steam-water heat exchanger and the water-to-water heat exchanger. A water-to-water heat exchanger inlet electric valve is installed on the water-to-water heat exchanger inlet side of the heating pipeline. The water distributor is responsible for stabilizing water volume and pressure. The heating booster pump inlet and outlet valves are used to cut off hot water from entering the heating booster pump and to cut off hot water from being supplied outward by the heating booster pump. The heating booster pump can pressurize the hot water exiting the water distributor and deliver it to the heating zone. The steam-water heat exchanger outlet electric valve can turn on and off the steam-water heat exchanger to supply hot water to the water distributor. The water-water heat exchanger outlet electric valve is used to turn on and off the heated water sent by the water-water heat exchanger. The water-water heat exchanger inlet electric valve is used to turn on and off the cold water entering the water-water heat exchanger for heating.

[0011] The heating pipeline, located on the water inlet side of the water-to-water heat exchanger's electric inlet valve, is equipped with a hot water circulation pump inlet valve, a hot water circulation pump, and a hot water circulation pump outlet valve in the order of cold water flow. The hot water circulation pump ensures continuous water circulation within the heating pipeline, while the hot water circulation pump inlet valve and hot water circulation pump outlet valve control the water inlet and outlet of the hot water circulation pump.

[0012] The circulating water pump is installed on the cooling water pipeline on the water inlet side of the cooling tower. The cooling water pipelines entering and exiting the circulating water pump are equipped with a circulating water pump inlet valve and a circulating water pump outlet valve. A cooling return valve is installed on the cooling water pipeline exiting the cooling tower. The circulating water pump is installed on the cooling water pipeline entering the cooling tower. The circulating water pump accelerates the cooling water into the cooling tower, improving the cooling effect. Two valves on either side of the circulating water pump's inlet and outlet are used to shut off the flow of cooling water in and out of the circulating water pump. The cooling return valve is installed on the pipeline on the cooling tower's outlet side, corresponding to the condenser's water inlet, to regulate the flow of cooling water returning to the condenser.

[0013] The return water pipeline, located on the side exiting the heating area, is equipped with a heating return main valve, a sludge remover, a water collector, and a recovery pipe main valve, in the order of water flow. Return water from the heating area enters the return water pipeline, passes through the sludge remover to remove impurities, and then enters the water collector for storage before returning to the heating pipeline for continued use.

[0014] The present invention adds a heat pump device to the existing steam heat exchange structure for heating, thereby improving the hot steam utilization rate of the condenser, reducing steam loss and improving efficiency. This system can choose to use a heat exchange device or a heat pump device to provide hot water under different working conditions; the absorption heat pump can use steam as a driving heat source to provide hot water, thereby increasing the thermal energy utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 : Schematic diagram of the structure of the present invention.

[0016] In the figure: 1. Intermediate pressure cylinder, 2. Low pressure cylinder, 3. First bypass steam pipe, 3-1. Steam main valve, 4. Second bypass steam pipe, 4-1. Steam manifold valve, 5. Steam inlet stop valve, 6. Steam outlet stop valve, 7. Steam cylinder, 8. Stop valve before electric valve of steam-water heat exchanger, 9. Electric valve of steam-water heat exchanger, 10. Stop valve after electric valve of steam-water heat exchanger, 11. Bypass valve of steam-water heat exchanger, 12. Steam-water heat exchanger, 13. Water-water exchanger Heat exchanger, 14. Steam-water heat exchanger drain valve, 15. Water-water heat exchanger drain valve, 16. Recovery water tank, 17. Condensate pump, 18. Condensate pump inlet stop valve, 19. Condensate pump outlet check valve, 20. Extraction pipe, 21. Condenser, 22. Exhaust pipe, 23. Absorption heat pump, 24. Heat pump inlet valve, 25. Cooling return valve, 26. Heat pump outlet valve, 27. Booster pump, 28. Circulating water pump, 29. . Circulating water pump inlet valve, 30. Circulating water pump outlet valve, 31. Cooling tower, 32. Hot water circulating pump, 33. Hot water circulating pump inlet valve, 34. Hot water circulating pump outlet valve, 35. Water-to-water heat exchanger inlet electric valve, 36. Water-to-water heat exchanger outlet electric valve, 37. Steam-to-water heat exchanger outlet electric valve, 38. Water distributor, 39. Heating pipeline, 40. Heating booster pump, 41. Heating booster pump inlet valve, 42. Heating booster pump Pump outlet valve, 43. Heating return water main valve, 44. Sludge remover, 45. Water collector, 45-1. Recovery pipe main valve, 45-2. Heat pump inlet valve, 45-3. Heat pump outlet valve, 45-4. Return water bypass valve, 46. Return water pipeline, 47. Demineralized water, 48. Make-up water tank, 49. Make-up water pump, 50. Make-up water pump outlet valve, 51. Make-up water pump inlet valve, 52. Heating area, 53. Make-up water pipe, 54. Cooling water pipeline. DETAILED DESCRIPTION

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1As shown, a heating system of a coal-fired power unit coupled with a heat pump includes a steam device with a cylinder and a steam pipeline, a heat exchange device with a heat exchanger, and a heating device with a heating pipeline 39 and a return water pipeline 46. The heating pipeline 39 and the steam pipeline are connected to the heat exchange device for heat exchange. The outlet of the heating pipeline 39 is connected to the heating area 52, and the inlet of the return water pipeline 46 is connected to the heating area 52 to recover hot water and send it back to the heating pipeline 39 for recycling. The return water pipeline 46 is on the side of the heating area 52 along the water flow direction in sequence. A heating return water main valve 43, a decontaminator 44, a water collector 45 and a recovery pipe main valve 45-1 are provided; the heating system also includes a heat pump device with an absorption heat pump 23, a condenser 21 and a cooling tower 31. The cylinder is connected to the condenser 21 and the heat medium inlet of the absorption heat pump 23 through a steam pipeline output. The condenser 21 is connected to the cooling tower 31 through a circulating cooling water pipeline 54. A circulating water pump 28 is provided on the cooling water pipeline 54. The circulating water pump 28 is provided on the cooling water pipeline 54 on the water inlet side of the cooling tower 31. 4, a circulating water pump inlet valve 29 and a circulating water pump outlet valve 30 are provided on the cooling water pipeline 54 entering and exiting the circulating water pump 28. A cooling return valve 25 is provided on the cooling water pipeline 54 on the outlet side of the cooling tower 31. The cooling water pipeline 54 is divided into two branches before entering the cooling tower 31 to connect the heat medium inlet and outlet of the absorption heat pump 23. The branch pipe connecting the heat medium inlet of the absorption heat pump 23 is provided with a heat pump inlet valve 24 and a booster pump 27, and the booster pump 27 is located on the side of the absorption heat pump 23. A heat pump outlet valve 26 is provided on the branch pipe connected to the hot medium outlet of the absorption heat pump 23; the absorption heat pump 23 is connected to the exhaust pipe 22 to discharge the steam after heat exchange, and a bypass is branched from the return pipe 46 to connect to the heating pipe 39 connected to the absorption heat pump 23, and a return water bypass valve 45-4 is provided on the bypass; the outlet of the return pipe 46 is connected to the cold medium inlet of the absorption heat pump 23 and is provided with a heat pump water inlet valve 45-2, and the inlet of the heating pipe 39 is connected to the cold medium outlet of the absorption heat pump 23 and is provided with a heat pump water outlet valve 45-3.

[0019] Furthermore, the cylinder includes an intermediate pressure cylinder 1 and a low pressure cylinder 2 connected by pipelines, and the steam device also includes a steam cylinder 7. The intermediate pressure cylinder 1 is connected to two steam pipelines connected to the condenser 21 and the steam cylinder 7 respectively, one of which is a first bypass steam pipe 3 connected to the steam cylinder 7. The first bypass steam pipe 3 is provided with a steam main valve 3-1 to open and close the steam output of the intermediate pressure cylinder 1. A second bypass steam pipe 4 is branched from the first bypass steam pipe 3 to connect to the heat medium inlet of the absorption heat pump 23. The second bypass steam pipe 4 is provided with a steam valve 4 for controlling steam delivery. -1, a steam inlet stop valve 5 is provided on the steam pipeline connecting the steam cylinder 7 to the output of the intermediate pressure cylinder 1, a second bypass steam pipe is branched out on the pipeline connecting the steam cylinder 7 to the intermediate pressure cylinder 1 to connect to the heat medium inlet of the absorption heat pump 23, a steam pipeline is connected to the low pressure cylinder 2 to connect to the condenser 21, and the steam pipeline is a steam extraction pipeline 20; the heat exchange device includes a steam-water heat exchanger 12, a water-water heat exchanger 13 and a recovery water tank 16 connected in series in sequence from front to back through the steam pipeline, and a steam-water heat exchanger dredging valve is provided on the steam pipeline connecting the steam-water heat exchanger 12 and the water-water heat exchanger 13. A water electric valve 14 is provided on the steam pipeline connected to the water-water heat exchanger 13 and the recovery water tank 16. A water-water heat exchanger drain valve 15 is provided. A steam pipe is connected between the steam-water heat exchanger 12 and the steam cylinder 7 and a steam outlet stop valve 6 is provided. The steam pipeline connecting the steam cylinder 7 and the steam-water heat exchanger 12 is provided with a steam-water heat exchanger electric valve front stop valve 8, a steam-water heat exchanger electric valve 9 and a steam-water heat exchanger electric valve rear stop valve 10 in sequence on one side of the steam-water heat exchanger 12 along the steam forward direction. A parallel steam bypass pipe is forked out from the steam pipeline. The steam-water heat exchanger bypass valve 11, one end of the steam bypass pipe is connected to the steam pipeline between the steam outlet stop valve 6 and the stop valve 8 before the steam-water heat exchanger electric valve, and the other end is connected to the steam pipeline between the stop valve 10 after the steam-water heat exchanger electric valve and the steam-water heat exchanger 12. The recovery water tank 16 is connected to the condenser 21 through the pipeline output. On the pipeline connecting the recovery water tank 16 to the condenser 21, a condensate pump inlet stop valve 18, a condensate pump 17 and a condensate pump outlet check valve 19 are sequentially arranged from the side of the recovery water tank 16 to the side of the condenser 21.

[0020] Furthermore, a water distributor 38 is provided on the heating pipe 39 between the steam-water heat exchanger 12 and the heating area 52, and a heating booster pump inlet valve 41, a heating booster pump 40 and a heating booster pump outlet valve 42 are provided on the heating pipe 39 between the water distributor 38 and the heating area 52 in the direction of hot water flow; a steam-water heat exchanger outlet electric valve 37 is provided on the heating pipe 39 between the water distributor 38 and the steam-water heat exchanger 12, and the steam-water heat exchanger outlet electric valve 37 is provided on the heating pipe 39 between the water distributor 38 and the steam-water heat exchanger 12. A water-to-water heat exchanger outlet electric valve 36 is provided on the heating pipeline 39 between the heat exchanger 12 and the water-to-water heat exchanger 13. A water-to-water heat exchanger inlet electric valve 35 is provided on the pipe section on the water inlet side of the water-to-water heat exchanger 13 of the heating pipeline 39. A hot water circulation pump inlet valve 33, a hot water circulation pump 32 and a hot water circulation pump outlet valve 34 are provided in sequence along the forward direction of cold water on the pipe section on the water inlet side of the water-to-water heat exchanger inlet electric valve 35 of the heating pipeline 39.

[0021] In addition, the heating system of the present invention is further provided with a water replenishment device, comprising a water replenishment pipe 53, a water replenishment tank 48, a water replenishment pump inlet valve 51, a water replenishment pump 49, and a water replenishment pump outlet valve 50. The outlet end of the water replenishment pipe 53 is connected to the heating pipeline after water flows through the heat pump outlet valve, while the inlet end of the water replenishment pipe 53 is connected to the water replenishment tank 48. The water replenishment pump inlet valve 51, the water replenishment pump 49, and the water replenishment pump outlet valve 50 are sequentially arranged on the water replenishment pipe 53 in the direction of water flow. The water replenishment device is connected to the heating pipeline to replenish the hot water supply. During operation, the water replenishment tank 48 needs to be filled with desalted water 47. The water replenishment pipe 53 is connected to the heating pipeline after water flows through the heat pump outlet valve. The desalted water 47 in the water replenishment tank 48 is pumped into the heating pipeline by the water replenishment pump 49. The water replenishment pump inlet valve 51 and outlet valve are used to cut off the inlet and outlet of the water replenishment pump 49.

[0022] This invention increases the utilization rate of the condenser's hot steam by adding a heat pump, reducing steam loss and improving efficiency. Depending on the operating conditions, hot water can be provided using either a heat exchanger or a heat pump. The absorption heat pump utilizes steam as a driving heat source to provide hot water, increasing thermal energy utilization efficiency. During operation, the invention has two operating modes. The first is when the heat pump alone provides heat. In this mode, the coal-fired power unit is operating at normal load, using the heat pump alone for heating.

[0023] First, desalted water 47 is activated to enter the makeup water tank 48. The makeup water pump inlet valve 51 and outlet valve 50 are opened, and makeup water pump 49 is started. The desalted water flows through the pipes into the heat supply line 39. During normal operation, exhaust steam from the intermediate pressure cylinder 1 and low pressure cylinder 2 enters the condenser 21. The condenser's circulating water pump inlet valve 29, circulating water pump 28, and circulating water pump outlet valve 30 are opened. The circulating water pump 28 is started to deliver water to the cooling tower 31 for circulation and cooling. When heat supply is required, the heat pump inlet valve 24 and heat pump outlet valve 26 are opened, and the booster pump 27 is started. Cooling circulating water flows through two branch pipes into and out of the absorption heat pump 23 for heat exchange. The absorption heat pump 23 is started, and the first bypass steam pipe 3-1 and steam manifold valve 4-1 are opened. Steam from the intermediate pressure cylinder 1 enters the absorption heat pump 23. Open both the hot water circulation pump inlet valve 33 and the hot water circulation pump outlet valve 34, and start the hot water circulation pump 32. Hot water heated in the heat pump is delivered via the heating pipeline 39 to the water distributor 38 for user heating. The heated water then flows from the water distributor through the heating booster pump inlet valve 41, the heating booster pump 40, and the heating booster pump outlet valve 42, entering the heating zone 52 for user heating. The heated water then flows through the return pipeline 46, the heating return main valve 43, and the decontamination device 44 for impurity removal. It is then stored in the manifold 45. Open the heat pump inlet valve 45-2 and the heat pump outlet valve 45-3, and simultaneously close the return bypass valve 45-4 to prevent the water in the return pipeline from returning directly to the heating pipeline 39 without passing through the absorption heat pump 23. The water in the manifold 45 is then delivered to the absorption heat pump 23 via the recovery pipe main valve 45-1 for circulation and heating. When the amount of water in the pipeline is sufficient, the water supply pump inlet valve 51, the water supply pump 49 and the water supply pump outlet valve 50 are closed.

[0024] The second type is that the heat exchange device provides heat alone. The steam system provides hot steam to the heat exchange device, and the cold water is heated alone through the heat exchanger for heating. At this time, the coal-fired power unit is in peak-shaving operation, and the pipelines on both sides of the cold medium inlet and outlet of the absorption heat pump of the heat pump device are closed. Water will not flow into the absorption heat pump for heat exchange, and the absorption heat pump does not participate in heating.

[0025] First, desalted water 47 is started to flow into the make-up water tank 48. The make-up water pump inlet valve 51 and the make-up water pump outlet valve 50 are opened, and the make-up water pump 49 is started. The desalted water flows through the pipes into the heat supply line 39. During normal operation of the unit, exhaust steam from the intermediate-pressure cylinder 1 and the low-pressure cylinder 2 enters the condenser 21. The condenser circulating water pump inlet valve 29, the circulating water pump 28, and the circulating water pump outlet valve 30 are opened. The circulating water pump 28 is started to send water to the cooling tower 31 for circulation and cooling. The condensed hot water from the condenser 21 does not enter the absorption heat pump 23 for heat exchange. Instead, it is sent to the outdoor cooling tower via the circulating water pump for cooling and then returned to the condenser for further condensation. The heat pump inlet valve 24 and the heat pump outlet valve 26 are closed. Open both the hot water circulation pump inlet valve 33 and the hot water circulation pump outlet valve 34, and start the hot water circulation pump 32. Hot water is delivered to the water distributor 38 through the heating pipeline 39. Open the bypass steam manifold 4-1 to open the second bypass steam pipe 4, allowing one path of the steam from the intermediate pressure cylinder 1 to enter the steam cylinder 7. Open the stop valve 8, the electric valve 9, and the stop valve 10 before the electric valve for the steam-water heat exchanger, allowing the steam from the steam cylinder 7 to enter the steam-water heat exchanger 12. The steam-water heat exchanger can then exchange heat with the water in the heating pipeline. The steam used up in the steam-water heat exchanger 12 will continue to enter the water-water heat exchanger 13 for further heat exchange. The pipelines exiting the steam-water heat exchanger 12 and the water-water heat exchanger 13 are respectively equipped with a steam-water heat exchanger drain valve 14 and a water-water heat exchanger drain valve 15 to drain the condensed steam. The water and steam after heat exchange enter the recovery water tank 16. The water in the recovery water tank 16 is fed into the condenser 21 via the condensate pump 17 for repeated recycling. The hot water used in the heating zone 52 is then fed through the return water line 46 and the heating return water main valve 43 to the decontaminator 44 for impurity treatment before entering the water collector 45 for storage. The return water bypass valve 45-4 is opened, and the heat pump inlet valve 45-2 and heat pump outlet valve 45-3 are simultaneously closed. The heating return water in the return water line 46 is now routed directly back to the heating line 39 via a bypass branched from the return water line 46. The return water bypass valve 45-4 is located on this bypass, and the water in the return water line does not pass through the absorption heat pump 23. When the water in the pipeline is sufficient, the feed water pump inlet valve 51, feed water pump 49, and feed water pump outlet valve 50 are closed, as in the first heating mode.

Claims

1. A heating system for a coal-fired power unit coupled with a heat pump, comprising a steam device with a cylinder and a steam pipeline, a heat exchange device with a heat exchanger, and a heating device with a heating pipeline (39) and a return water pipeline (46). The heating pipeline (39) and the steam pipeline are connected to the heat exchange device for heat exchange. The outlet of the heating pipeline (39) is connected to the heating area (52), and the inlet of the return water pipeline (46) is connected to the heating area (52). Hot water is recovered and sent back to the heating pipeline (39) for recycling. The heating system also includes a heat pump device with an absorption heat pump (23), a condenser (21) and a cooling tower (31). The cylinder is connected to the condenser (21) and the heat medium inlet of the absorption heat pump (23) through a steam pipeline output. The condenser (21) is connected to the cooling tower (31) through a circulating cooling water pipeline (54). A circulating water pump (28) is provided on the cooling water pipeline (54). The cooling water pipeline (54) is divided into two branches before entering the cooling tower (31) and connected to the absorption heat pump (23). The heat medium inlet and outlet of the absorption heat pump (23) are connected to the exhaust pipe (22) to discharge the steam after heat exchange. A bypass is branched from the return water pipeline (46) to connect to the heat supply pipeline (39) connected to the absorption heat pump (23), and a return water bypass valve (45-4) is provided on the bypass; the outlet of the return water pipeline (46) is connected to the cold medium inlet of the absorption heat pump (23) and is provided with a heat pump water inlet valve (45-2), and the inlet of the heat supply pipeline (39) is connected to the cold medium outlet of the absorption heat pump (23) and is provided with a heat pump water outlet valve (45-3); The cylinder comprises a medium-pressure cylinder (1) and a low-pressure cylinder (2) connected by pipelines, and the steam device further comprises a steam cylinder (7). The medium-pressure cylinder (1) is connected to two steam pipelines respectively connected to the condenser (21) and the steam cylinder (7). A steam inlet stop valve (5) is provided on the steam pipeline connected to the output of the medium-pressure cylinder (1) by the steam cylinder (7). A second bypass steam pipe is branched out from the pipeline connected to the medium-pressure cylinder (1) by the steam cylinder (7) to connect to the heat medium inlet of the absorption heat pump (23). The low-pressure cylinder (2) is connected to a steam pipeline connected to the condenser (21); the heat exchange device comprises A steam-water heat exchanger (12), a water-water heat exchanger (13) and a recovery water tank (16) are sequentially connected in series through a steam pipeline. A steam pipe is connected between the steam-water heat exchanger (12) and the steam cylinder (7) and a steam outlet stop valve (6) is provided. The recovery water tank (16) is connected to the condenser (21) through a pipeline output. A steam-water heat exchanger drain electric valve (14) is provided on the steam pipeline connecting the steam-water heat exchanger (12) and the water-water heat exchanger (13), and a water-water heat exchanger drain valve (15) is provided on the steam pipeline connecting the water-water heat exchanger (13) and the recovery water tank (16).

2. The heating system of the coal-fired power unit coupled with a heat pump according to claim 1 is characterized in that The steam pipeline connecting the steam cylinder (7) and the steam-water heat exchanger (12) is provided with a steam-water heat exchanger electric valve front stop valve (8), a steam-water heat exchanger electric valve (9) and a steam-water heat exchanger electric valve rear stop valve (10) in sequence along the steam forward direction on one side of the steam-water heat exchanger (12). A parallel steam bypass pipe is branched out from the steam pipeline, and a steam-water heat exchanger bypass valve (11) is provided on the steam bypass pipe. One end of the steam bypass pipe is connected to the steam pipeline between the steam outlet stop valve (6) and the steam-water heat exchanger electric valve front stop valve (8), and the other end is connected to the steam pipeline between the steam-water heat exchanger electric valve rear stop valve (10) and the steam-water heat exchanger (12).

3. The heating system of the coal-fired power unit coupled with a heat pump according to claim 1 is characterized in that A condensate pump inlet stop valve (18), a condensate pump (17) and a condensate pump outlet check valve (19) are sequentially provided on a pipeline connecting the recovery water tank (16) to the condenser (21) side.

4. The heating system of the coal-fired power unit coupled with a heat pump according to claim 1 is characterized in that A heat pump inlet valve (24) and a booster pump (27) are provided on the branch pipe connected to the heat medium inlet of the absorption heat pump (23), and the booster pump (27) is located on one side of the absorption heat pump (23). A heat pump outlet valve (26) is provided on the branch pipe connected to the heat medium outlet of the absorption heat pump (23).

5. The heating system of the coal-fired power unit coupled with a heat pump according to claim 1 is characterized in that A water distributor (38) is provided on the heating pipeline (39) between the steam-water heat exchanger (12) and the heating area (52); a heating booster pump inlet valve (41), a heating booster pump (40) and a heating booster pump outlet valve (42) are provided in sequence along the forward direction of hot water on the heating pipeline (39) between the water distributor (38) and the steam-water heat exchanger (12); a steam-water heat exchanger outlet electric valve (37) is provided on the heating pipeline (39) between the steam-water heat exchanger (12) and the water-water heat exchanger (13); and a water-water heat exchanger outlet electric valve (36) is provided on the heating pipeline (39) between the steam-water heat exchanger (12) and the water-water heat exchanger (13); and a water-water heat exchanger inlet electric valve (35) is provided on the pipe section of the heating pipeline (39) on the water inlet side of the water-water heat exchanger (13).

6. The heating system of the coal-fired power unit coupled with a heat pump according to claim 5 is characterized in that The heating pipeline (39) is provided with a hot water circulation pump inlet valve (33), a hot water circulation pump (32) and a hot water circulation pump outlet valve (34) in sequence along the cold water forward direction on the pipe section on the water inlet side of the water-to-water heat exchanger water inlet electric valve (35).

7. The heating system of the coal-fired power unit coupled with a heat pump according to claim 1 is characterized in that The circulating water pump (28) is arranged on the cooling water pipeline (54) on the water inlet side of the cooling tower (31), and the cooling water pipeline (54) entering and exiting the circulating water pump (28) is provided with a circulating water pump inlet valve (29) and a circulating water pump outlet valve (30), and the cooling water pipeline (54) on the water outlet side of the cooling tower (31) is provided with a cooling return water valve (25).

8. The heating system of the coal-fired power unit coupled with a heat pump according to claim 1 is characterized in that The return water pipeline (46) is provided with a heating return water main valve (43), a dirt remover (44), a water collector (45) and a recovery pipe main valve (45-1) in sequence along the forward direction of water flow on the pipe section on the side of the heat supply area (52).

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