Air-cooling unit antifreeze system and method based on continuous exhaust steam waste heat from deaerator

Abstract

The present invention relates to an antifreeze system and method for an air-cooled unit based on waste heat from a continuous deaerator exhaust. The antifreeze device includes an air supply pipeline, an air jet, a primary heat exchanger, and a deaerator exhaust heating pipe connected to the deaerator continuous exhaust pipeline. The deaerator exhaust heating pipe is used to draw all the deaerator continuous exhaust steam from the deaerator continuous exhaust pipeline. The air supply pipeline exchanges heat with the deaerator exhaust heating pipe via the primary heat exchanger to increase the gas temperature within the air supply pipeline. Several air jets are positioned in a low-temperature area of ​​the air-cooled unit, and the nozzles of the air jets spray heated gas toward the low-temperature area. The present invention does not require heat from outside the thermal power unit, but instead improves energy utilization by readjusting heat distribution. It is relatively simple to implement, has a good antifreeze effect, and can effectively reduce the operating back pressure of the steam turbine unit in winter, effectively improving the unit's economic efficiency, safety, and stability during winter operation.

Description

Technical Field

[0001] The present invention relates to the technical field of direct air cooling, and in particular to an antifreeze system and method for an air-cooling island of an air-cooling unit. Background Art

[0002] In recent years, with the rapid development of my country's power industry, large-capacity, high-parameter thermal power generating units have been built all over the country. For the vast areas of northwest my country, due to the severe shortage of water resources and the country's environmental protection requirements for new units, the use of air-cooled units has become a relatively common way to cool the exhaust steam of steam turbine units. There are generally two types of air-cooled units, one is direct air-cooled units and the other is indirect air-cooled units. The structure of the direct air-cooled unit is shown in the attached figure. Figure 1 As shown, the exhaust steam of the steam turbine directly enters the cooling system of the unit's air-cooling island, and the air is driven by the air-cooling fan to cool the exhaust steam of the unit by convection heat exchange; the indirect air-cooling unit uses the circulating medium to exchange heat with the exhaust steam of the steam turbine unit for cooling.

[0003] However, the cooling characteristics of air-cooled units mean that their operation is significantly affected by ambient temperature. This is particularly true in winter, when extremely low ambient temperatures can easily cause freezing and cracking of the heat exchange tubes in the cooling island of an air-cooled unit, seriously impacting the safety and stability of the unit. Existing antifreeze systems typically incorporate shielding devices such as blinds, but these are not ideal. Therefore, a new antifreeze system and method for air-cooled units is needed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects in the prior art, thereby providing an air-cooling unit antifreeze system and method based on continuous exhaust steam waste heat from a deaerator.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] An air-cooling unit antifreeze system based on the waste heat of continuous exhaust steam from a deaerator, comprising a deaerator continuous exhaust steam pipe, an air-cooling unit and an antifreeze device, wherein the deaerator continuous exhaust steam pipe is connected to the continuous exhaust port of the deaerator;

[0007] The antifreeze device includes an air supply pipe, an ejector, a primary heat exchanger, and a deaerator exhaust heating pipe connected to the deaerator continuous exhaust pipe. The deaerator exhaust heating pipe is used to draw out at least part of the deaerator continuous exhaust from the deaerator continuous exhaust pipe. The air supply pipe exchanges heat with the deaerator exhaust heating pipe through the primary heat exchanger to increase the gas temperature in the air supply pipe. The ejector is arranged at the terminal end of the air supply pipe. Several of the ejectors are arranged in the low-temperature area of ​​the air-cooling unit, and the nozzles of the ejectors spray the heated gas toward the low-temperature area.

[0008] Preferably, the antifreeze system also includes a control module and several low-temperature area temperature detection modules. The low-temperature area temperature detection modules are dispersedly arranged in the tube bundle of the low-temperature area of ​​the air-cooling unit and are communicatively connected to the control module. The control module is communicatively connected to the antifreeze device and is used to control the gas temperature in the air supply pipe and the injection range of the injector based on the temperature of the low-temperature area.

[0009] Preferably, the antifreeze device also includes a secondary hot steam pipe and a secondary heat exchanger connected to the heat source, the temperature of the steam in the secondary hot steam pipe is higher than the temperature of the deaerator continuous exhaust steam in the deaerator exhaust heating pipe, the secondary heat exchanger is arranged between the primary heat exchanger and the ejector, the air supply pipe exchanges heat with the secondary hot steam pipe through the secondary heat exchanger, and the terminal of the secondary hot steam pipe is connected to the condensate recovery tank.

[0010] Preferably, a first regulating valve is provided on the deaerator exhaust steam heating pipe; the control module is communicatively connected to the first regulating valve, and is used to regulate the deaerator continuous exhaust steam flow in the deaerator exhaust steam heating pipe based on the temperature of the low temperature area;

[0011] The antifreeze system also includes a back pressure detection module for detecting the back pressure of the steam turbine, and the back pressure detection module is communicatively connected to the control module; the secondary hot steam pipe is provided with an on-off unit, and the on-off unit is communicatively connected to the control module, and is used to conduct the secondary hot steam pipe when the back pressure of the steam turbine is higher than the set back pressure and the opening of the first regulating valve is at the maximum; the secondary hot steam pipe is provided with a second regulating valve for adjusting the gas temperature in the gas supply pipe based on the temperature of the low-temperature area.

[0012] Preferably, the antifreeze device also includes a first temperature detector and a second temperature detector, the first temperature detector is located between the first-level heat exchanger and the second-level heat exchanger, and the second temperature detector is located between the second-level heat exchanger and the ejector, the first temperature detector and the second temperature detector are respectively connected to the control module, and are used to adjust the deaerator continuous exhaust flow in the deaerator exhaust heating pipe and the steam flow in the second-level hot steam pipe based on the detected temperature.

[0013] Preferably, the terminal end of the deaerator exhaust heating pipe is connected to the condensate recovery tank, and the condensate recovery tank is connected to the unit hot well through a multi-stage water seal, and the condensate recovery tank is provided with a drain pipe and a drain pipe isolation valve;

[0014] The terminal end of the secondary hot steam pipe is communicated with the condensate recovery tank.

[0015] Preferably, the air cooling unit is an indirect air cooling unit or a direct air cooling unit;

[0016] When the air-cooling unit is a direct air-cooling unit, the direct air-cooling unit includes an air-cooling island and a condensate tank. The air-cooling island is connected to the steam turbine through an exhaust pipe. The air-cooling island includes a plurality of triangular cooling units. The triangular cooling unit is in an inverted "V" shape and includes two inclined condensing units. The condensing unit includes a downstream tube bundle and a countercurrent tube bundle. The downstream tube bundle is connected to the condensate tank. The plurality of ejectors are located between the two inclined condensing units and are respectively located at the lower end of the downstream tube bundle and the upper end of the countercurrent tube bundle. The lower end of the downstream tube bundle and the upper end of the countercurrent tube bundle are low-temperature areas. The low-temperature area temperature detection module includes a temperature sensor located in the condensate header at the lower end of the downstream tube bundle and a temperature sensor located in the vacuum header at the upper end of the countercurrent tube bundle.

[0017] When the air-cooling unit is an indirect air-cooling unit, the indirect air-cooling unit includes an intercooling tower and a condenser. The condenser is connected to the turbine through an exhaust pipe, and the intercooling tower is connected to the condenser through a circulation pipeline. The intercooling tower includes a plurality of cooling triangle radiators. The cooling triangle radiators have a connected water inlet pipe and a return pipe inside. The water inlet pipe and the return pipe are respectively connected to the circulation pipeline. The lower end of the return pipe is a low-temperature area. The plurality of jets correspond to the plurality of cooling triangle radiators of the intercooling tower, and the jet direction of the jet is toward the lower end of the return pipe; the low-temperature area temperature detection module includes a temperature sensor located at the lower end of the return pipe.

[0018] Preferably, the air supply pipeline includes an air compressor, the gas in the air supply pipeline is compressed air, the air compressor is an adjustable pressure air compressor, and the control module is communicatively connected to the air compressor and is used to adjust the pressure of the air compressor based on the temperature of the low-temperature area;

[0019] The sprayer includes a first nozzle and a second nozzle, the spray range of the second nozzle is larger than the spray range of the first nozzle, and the control module is connected to the sprayer and is used to select to open the first nozzle or the second nozzle or open the first nozzle and the second nozzle at the same time based on the condensate temperature;

[0020] When the air-cooling unit is a direct air-cooling unit, at least two of the injectors are correspondingly provided for one downstream tube bundle, and at least two of the injectors are correspondingly provided for one upstream tube bundle;

[0021] In two adjacent air jets, the spraying ranges of the two second nozzles partially overlap, and the spraying range of the second nozzle touches or partially overlaps with the edge of the spraying range of the first nozzle of the other air jet;

[0022] The spray range of the second nozzle of the injector close to the edge of the downstream tube bundle exceeds the edge of the downstream tube bundle;

[0023] When the air-cooling unit is an indirect air-cooling unit, the plurality of injectors are vertically arranged at positions corresponding to the low-temperature area of ​​the cooling triangle radiator and the lower end of the return water pipe, and are controlled by the control module to be opened in sequence from bottom to top based on the return water temperature; the opening priority of all the first nozzles and the second nozzles of the injectors at the same height is higher than the opening priority of all the first nozzles and the second nozzles of the injectors at a higher height;

[0024] The spraying ranges of two upper and lower adjacent second nozzles partially overlap, and the spraying range of the second nozzle of one of the nozzles contacts or partially overlaps with the edge of the spraying range of the first nozzle in the other nozzle.

[0025] To achieve the above object, the present invention adopts the following technical solutions:

[0026] An antifreeze method for an air-cooled unit based on continuous exhaust steam waste heat from a deaerator, using the above-mentioned antifreeze system, comprises the following steps:

[0027] Opening the deaerator exhaust steam heating pipe to draw out at least a portion of the deaerator continuous exhaust steam from the deaerator continuous exhaust steam pipeline;

[0028] Open the gas supply pipeline. The gas in the gas supply pipeline passes through the first-stage heat exchanger and exchanges heat with the exhaust steam of the deaerator to increase the gas temperature. The exhaust steam of the deaerator condenses into water.

[0029] The ejector is started, and the gas with the increased temperature is injected into the low temperature area of ​​the air cooling unit.

[0030] Preferably,

[0031] When the air-cooling unit is a direct air-cooling unit, the antifreeze device adopts the following control logic:

[0032] Detecting the condensate temperature in the condensate header at the lower end of the downstream tube bundle, and controlling the gas temperature and injection range of the injector corresponding to the lower end of the downstream tube bundle according to the condensate temperature in the condensate header;

[0033] Detecting the condensate temperature of the vacuum header at the upper end of the counter-flow tube bundle, and controlling the gas temperature and injection range of the ejector corresponding to the upper end of the counter-flow tube bundle according to the condensate temperature of the vacuum header;

[0034] If the condensate temperature is lower than the first set value, the first regulating valve on the exhaust steam heating pipe of the deaerator is opened, the air compressor on the air supply pipe is turned on, and the first nozzle is turned on to heat the lower end of the downstream tube bundle and / or the upper end of the countercurrent tube bundle;

[0035] If the condensate temperature is lower than the second set value, the opening of the first regulating valve on the deaerator exhaust steam heating pipe is increased to increase the continuous exhaust steam flow of the deaerator in the deaerator exhaust steam heating pipe, increase the pressure of the air compressor on the air supply pipeline, close the first nozzle, and open the second nozzle to heat the lower end of the downstream tube bundle and / or the upper end of the countercurrent tube bundle;

[0036] If the condensate temperature is lower than the third set value, the first regulating valve on the deaerator exhaust steam heating pipe is adjusted to the maximum opening, the deaerator continuous exhaust steam flow in the deaerator exhaust steam heating pipe is increased, the pressure of the air compressor on the air supply pipe is increased, the first nozzle is opened, the second nozzle is opened, and the lower end of the downstream tube bundle and / or the upper end of the countercurrent tube bundle is heated;

[0037] If the condensate temperature is lower than the fourth set value and the back pressure of the steam turbine is detected to be higher than the set back pressure, the secondary hot steam pipe is opened to increase the pressure of the air compressor on the air supply pipe. The gas in the air supply pipe passes through the primary heat exchanger and the secondary heat exchanger in sequence for secondary heating. The first nozzle is opened and the second nozzle is opened to heat the lower end of the downstream tube bundle and / or the upper end of the countercurrent tube bundle.

[0038] When the air-cooling unit is an indirect air-cooling unit, the antifreeze device adopts the following control logic:

[0039] Detect the return water temperature at the lower end of the return water pipe, and control the gas temperature and injection range of the corresponding injector according to the return water temperature;

[0040] If the return water temperature is lower than the first set value, the first regulating valve on the exhaust steam heating pipe of the deaerator is opened, the air compressor on the air supply pipe is turned on, and the first nozzle in the air injector at the lowest end of the return water pipe is turned on to heat the lowest end of the return water pipe;

[0041] If the return water temperature is lower than the second set value, the opening of the first regulating valve on the deaerator exhaust steam heating pipe is increased to increase the continuous exhaust steam flow of the deaerator in the deaerator exhaust steam heating pipe, increase the pressure of the air compressor on the air supply pipe, close the first nozzle of the air injector at the bottom end of the return water pipe, and open the second nozzle to heat the bottom end of the return water pipe;

[0042] If the return water temperature is lower than the third set value, the first regulating valve on the deaerator exhaust steam heating pipe is adjusted to the maximum opening, the continuous exhaust steam flow of the deaerator in the deaerator exhaust steam heating pipe is increased, the pressure of the air compressor on the air supply pipe is increased, and the first nozzle and the second nozzle of the air injector at the lower end of the return water pipe are opened at the same time to heat the lower end of the return water pipe;

[0043] If the condensate temperature is lower than the fourth set value and the back pressure of the steam turbine is detected to be higher than the set back pressure, the secondary hot steam pipe is opened to increase the pressure of the air compressor on the air supply pipe. The gas in the air supply pipe passes through the primary heat exchanger and the secondary heat exchanger in sequence for secondary heating. At the same time, the first nozzle and the second nozzle of at least two groups of nozzles located at the height direction of the lower end of the return pipe are opened to heat the middle and lower end of the return pipe and heat the lower end of the downstream tube bundle and the upper end of the upstream tube bundle.

[0044] After the set time, if it is detected that the back pressure of the steam turbine is lower than the set back pressure and the return water temperature is still lower than the fourth set value, it will continue to be maintained until the return water temperature is higher than the fourth set value.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The antifreeze system and method for an air-cooled unit based on the waste heat of the continuous exhaust steam of the deaerator provided in the above technical solution fully utilizes the continuous exhaust steam of the deaerator that would otherwise be wasted, and uses all the heat of the continuous exhaust steam of the deaerator to heat the gas in the gas supply pipe, and then sprays the gas into the low-temperature area of ​​the air-cooled unit, that is, the position with lower temperature, to increase the temperature of the tube bundle in the low-temperature area from the outside, thereby preventing the condensed water or return water therein from freezing in the tube bundle, and even freezing and cracking the tube bundle. Compared with the existing antifreeze methods of air-cooled units, such as the antifreeze method of increasing the operating back pressure, the antifreeze method of setting roller curtains or shutters, and the antifreeze method of setting electric heating pipes, the present invention does not require heat outside the thermal power unit, but instead improves energy utilization by readjusting the heat distribution of the entire thermal power unit. The implementation method is relatively simple and the antifreeze effect is good. At the same time, it can effectively reduce the operating back pressure of the turbine unit in winter. The use of the antifreeze system of the present invention can enable the thermal power unit to operate under lower back pressure without affecting the normal exhaust volume of the turbine entering the air-cooled unit, that is, ensuring the exhaust steam flow and temperature inside the air-cooled unit, and improving the economy and safety and stability of the unit operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are 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.

[0048] Figure 1 This is a structural diagram of an existing direct air cooling unit.

[0049] Figure 2 This is a structural schematic diagram of the antifreeze system of the direct air cooling unit according to the first embodiment of the present invention.

[0050] Figure 3 This is a structural schematic diagram of a triangular cooling unit according to a first embodiment of the present invention, showing the position of the injector in the downstream tube bundle.

[0051] Figure 4 This is a structural schematic diagram of a triangular cooling unit according to a first embodiment of the present invention, which shows the position of the injector in the counter-flow tube bundle.

[0052] Figure 5 Schematic diagram of the structure of the ejector according to an embodiment of the present invention.

[0053] Figure 6 This is a schematic diagram of the distribution of the ejectors on a single-side condensing unit according to the first embodiment of the present invention.

[0054] Figure 7 This is a structural diagram of the antifreeze system of the indirect air cooling unit according to the second embodiment of the present invention.

[0055] Figure 8 This is a schematic diagram of the distribution of the ejectors in the heat dissipation module of the indirect cooling tower according to the second embodiment of the present invention.

[0056] Figure 9 This is a schematic diagram of the distribution of the first nozzle and the second nozzle at the lower end of the return pipe in embodiment 2 of the present invention.

[0057] Description of reference numerals:

[0058] 10. Air-cooling island; 11. Condensing unit; 111. Downstream tube bundle; 112. Countercurrent tube bundle; 12. Condensate header; 13. Vacuum system; 131. Vacuum header; 14. Temperature sensor; 15. Exhaust pipe;

[0059] 20. Indirect cooling tower; 21. Cooling triangle radiator; 22. Return pipe; 23. Inlet pipe;

[0060] 30. Deaerator continuous exhaust pipe; 31. Drain pipe; 32. Drain pipe isolation valve; 33. Multi-stage water seal; 34. Eighth isolation valve; 35. Condensate recovery tank;

[0061] 40. Air supply pipeline; 41. Air compressor; 42. Third isolation valve; 43. Fourth isolation valve; 44. First temperature detector; 45. Second temperature detector; 46. Fifth isolation valve;

[0062] 50. Injector; 51. First nozzle; 52. Second nozzle; 53. First control valve; 54. Second control valve;

[0063] 60. Primary heat exchanger;

[0064] 70. Deaerator exhaust steam heating pipe; 71. First isolation valve; 72. Second isolation valve; 73. First regulating valve;

[0065] 80. Secondary hot steam pipe; 81. On / off unit; 82. Second regulating valve; 83. Sixth isolation valve; 84. Seventh isolation valve;

[0066] 90. Secondary heat exchanger. DETAILED DESCRIPTION

[0067] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all 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.

[0068] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0069] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0070] The antifreeze systems and methods of the present invention vary depending on the air-cooling unit, specifically in the nozzle placement and the temperature detected by the control module. The following briefly describes the integration of the antifreeze system with different air-cooling units to explain the working principles of the antifreeze system and method of the present invention.

[0071] Example 1

[0072] The air cooling unit in this embodiment is a direct air cooling unit. The existing direct air cooling unit is as shown in the attached Figure 1As shown, the exhaust steam of the steam turbine of the thermal power generator set is discharged to the air-cooling island 10 arranged outdoors through the exhaust pipe 15. The air-cooling island 10 includes a number of triangular cooling units. The triangular cooling units are in an inverted "V" shape and include two inclined condensing units 11. An axial cooling fan is set below the air-cooling island 10 to make air flow through the outer surface of the condensing unit 11, cooling the turbine exhaust steam in the condensing unit 11 into water. The condensed water flows into the condensate tank and is then sent back to the cooling system of the steam turbine. Each condensing unit 11 includes a downstream tube bundle 111 and a countercurrent tube bundle 112. The exhaust pipe is located at the top and the condensate header 12 is located at the bottom. The upper end of the downstream tube bundle 111 is connected to the exhaust pipe, and the lower end is connected to the condensate header 12. The flow direction therein is as shown in FIG. Figure 1 As shown by the arrow on the top, it is from top to bottom. Therefore, in cold weather, the lower end of the downstream tube bundle 111 is prone to freezing and cracking. The direct air cooling system also includes a vacuum system 13, which is used to establish and maintain the low back pressure (exhaust pressure) of the steam turbine unit and the vacuum of the condensing unit 11, to ensure that the exhaust steam of the steam turbine smoothly enters the air-cooling island 10 when the thermal power generator unit is started and operated, and to timely remove the air and other non-condensable gases in the direct air cooling system when the unit is operating normally, to maintain the vacuum of the air-cooled condenser, and to reduce the corrosion of the pipeline and the air-cooled condenser. Corrosion, reducing the volume of non-condensable gas in the air-cooled condenser, and reducing the back pressure of the unit. The lower the back pressure of the unit, the higher the economic efficiency. The function of the countercurrent tube bundle 112 is to connect the downstream tube bundle 111 and the vacuum system 13. The countercurrent tube bundle 112 is located in the middle of the condensing unit 11. The lower end of the countercurrent tube bundle 112 is connected to the downstream tube bundle 111, and the upper end is connected to the vacuum system 13. The temperature of the air flow inside the countercurrent tube bundle 112 decreases, and the small amount of water vapor contained in it will form condensate at the upper end of the countercurrent light beam, which will then freeze and cause freeze blockage and cracking. It can be seen that the low-temperature area of ​​the direct air-cooled unit is the lower end of the downstream tube bundle and the upper end of the countercurrent tube bundle.

[0073] Based on this, the antifreeze system of this embodiment includes a deaerator continuous exhaust pipe 30 and an antifreeze device, wherein the antifreeze device includes an air supply pipe, an ejector, a primary heat exchanger, and a deaerator exhaust heating pipe connected to the deaerator continuous exhaust pipe 30. The deaerator exhaust heating pipe is used to lead out all the deaerator continuous exhaust steam from the deaerator continuous exhaust pipe 30, so as to utilize the deaerator continuous exhaust steam that was originally directly discharged; the air supply pipe exchanges heat with the deaerator exhaust heating pipe through the primary heat exchanger to increase the gas temperature in the air supply pipe, the ejector is arranged at the terminal of the air supply pipe, and the heated gas is ejected from the ejector, and a plurality of ejectors are arranged between two inclined condensing units 11, and are respectively located at the lower end of the downstream tube bundle 111 and the upper end of the countercurrent tube bundle 112, and the nozzles of the ejectors are directed toward the downstream tube bundle 111 and the countercurrent tube bundle 112, as shown in the attached figure. Figure 3 and attached Figure 4 shown.

[0074] In severe cold seasons, compared with existing antifreeze methods for direct air-cooling units, such as the antifreeze method of increasing the operating back pressure, the antifreeze method based on the temperature and humidity of the vacuum pipe, the antifreeze method of setting roller curtains or blinds, and the antifreeze method of setting electric heating pipes, this embodiment uses the deaerator's continuous exhaust steam that would otherwise be wasted to heat the gas in the gas supply pipe, and then injects the gas to a lower temperature position in the air-cooling island 10, thereby increasing the temperature of the lower end of the downstream tube bundle 111 and the upper end of the countercurrent tube bundle 112, thereby preventing the condensed water therein from freezing in the tube bundle, or even freezing and cracking the tube bundle. The present invention does not require heat from outside the thermal power unit, but improves energy utilization by readjusting the heat distribution of the entire thermal power unit. The implementation method is relatively simple and the antifreeze effect is good. At the same time, it can effectively reduce the operating back pressure of the turbine unit in winter. The use of the antifreeze system of the present invention can enable the thermal power unit to operate under lower back pressure without affecting the normal exhaust volume of the turbine entering the air-cooled unit, that is, ensuring the exhaust steam flow and temperature inside the air-cooled unit, and improving the economy, safety and stability of the unit operation.

[0075] More preferably, this embodiment sets the jet inside the air-cooling island 10, between two inclined condensing units 11, and uses the condensing units 11 to block the horizontal ambient wind, so that the hot air ejected by the jet covers more of the condensing units 11, thereby increasing the temperature of the specific area and improving the heat utilization rate.

[0076] As attached Figure 2 As shown, the starting end of the deaerator exhaust heating pipe is connected to the deaerator continuous exhaust pipe 30, and high-temperature steam is introduced. The middle section of the deaerator exhaust heating pipe is connected to the first-stage heat exchanger. The heat of the high-temperature steam is transferred to the gas in the gas supply pipe through the first-stage heat exchanger. The high-temperature steam is cooled and condensed. The terminal end of the deaerator exhaust heating pipe is connected to the condensate recovery tank 35. The condensate is recovered to the condensate recovery tank 35, and the condensate recovery tank 35 is connected to the unit hot well through a multi-stage water seal 33. The unit hot well is the place where the condensate of the entire system is gathered and reused. The multi-stage water seal 33 can effectively prevent vacuum leakage of the unit hot well. The condensate recovery tank 35 is provided with a drain pipe 31 and a drain pipe isolation valve 32. The drain pipe 31 is used to discharge non-condensable gas, and the drain pipe isolation valve 32 facilitates system maintenance and isolation.

[0077] The antifreeze device of this embodiment can be manually controlled, including manual start-up, manual adjustment of the gas flow in the gas supply pipeline, and manual adjustment of the flow of the deaerator continuous exhaust steam in the deaerator exhaust heating pipe to adjust the gas temperature in the gas supply pipeline. The injector can be manually replaced and the injection range of the injector can be adjusted as needed.

[0078] Of course, as a preferred embodiment, this embodiment can also adopt an automatic control method. Specifically, the antifreeze system of this embodiment also includes a control module and several low-temperature area temperature detection modules. The control module can be integrated into the DCS system of the thermal power generator set, and has a built-in control program to control the antifreeze device based on the temperature of the low-temperature area, the ambient temperature and the back pressure of the unit.

[0079] Specifically, the low-temperature zone temperature detection module in the direct air-cooling unit includes a temperature sensor located in the condensate manifold at the lower end of the downstream tube bundle and a temperature sensor located in the vacuum manifold at the upper end of the counterflow tube bundle. This module detects the condensate temperature at locations prone to freezing and is referred to as the condensate temperature detection module. Temperature sensors 14 are located in the condensate manifold 12 at the lower end of each downstream tube bundle 111 and in the vacuum manifold 131 at the upper end of the counterflow tube bundle 112, respectively. These sensors are positioned away from the ejector 50 to prevent the detection results from being affected by the hot gas ejected by the ejector 50. The temperature sensors transmit the detected temperature data to the control module, which communicates with the air supply pipeline 40 and adjusts the gas temperature within the pipeline 40 based on the condensate temperature. One or more temperature sensors 14 can be installed for each downstream tube bundle 111 or counterflow tube bundle 112. If multiple temperature sensors 14 are installed, the temperatures detected by these sensors 14 can be averaged to improve detection accuracy. The injectors 50 corresponding to each downstream tube bundle 111 or countercurrent tube bundle 112 can be independently controlled. Specifically, the injection range of each injector 50 is controlled based on the temperature detected by the temperature sensor 14 corresponding to each downstream tube bundle 111 or countercurrent tube bundle 112. Furthermore, additional temperature sensors can be installed inside or near the injectors 50 to monitor the temperature of the hot air injected by the injectors 50 in real time and determine whether the antifreeze device is functioning properly.

[0080] This embodiment has a multi-level control mode. Specifically, as shown in the attached Figure 2 As shown, a first regulating valve 73 is provided on the deaerator exhaust steam heating pipe 70; the control module is in communication with the first regulating valve 73 and is configured to regulate the deaerator continuous exhaust steam flow rate in the deaerator exhaust steam heating pipe 70 based on the condensate temperature. When the condensate temperature decreases, the opening of the first regulating valve 73 increases, more deaerator continuous exhaust steam flows into the deaerator exhaust steam heating pipe 70, and the temperature of the gas ejected by the ejector 50 increases. When the condensate temperature increases, the opening of the first regulating valve 73 decreases, less deaerator continuous exhaust steam flows into the deaerator exhaust steam heating pipe 70, and the temperature of the gas ejected by the ejector 50 decreases. When the condensate temperature exceeds a first set value, it is determined that the air-cooling island 10 is not prone to freezing, and the first regulating valve 73 can be closed. The specific value of the first set value is set according to the actual operating conditions of the steam turbine air-cooling unit.

[0081] Preferably, the antifreeze system of this embodiment further includes a backpressure detection module (not shown) for detecting turbine backpressure. This module is a conventional detection unit in the DCS system of a thermal power generator set and is therefore not described in detail here. The backpressure detection module is communicatively connected to the control module, transmitting turbine backpressure data to the control module for controlling the antifreeze device.

[0082] If the opening of the first regulating valve 73 reaches the maximum, and the ambient temperature or condensate temperature is still decreasing, it is generally necessary to increase the back pressure of the turbine, which will affect the economic efficiency of the unit operation. At this time, other heat sources can be introduced, such as partial low-pressure extraction steam from the unit (such as five-stage extraction steam), and the antifreeze device can be used for antifreeze. Compared with the traditional operation mode of increasing the back pressure of the turbine unit for antifreeze, it has less impact on the overall economic efficiency of the unit. Specifically, the system of this embodiment also includes a secondary hot steam pipe 80 and a secondary heat exchanger 90 connected to other heat sources. The secondary hot steam pipe 80 is provided with an on-off unit 81, which is communicatively connected to the control module and is used to conduct the secondary hot steam pipe 80 when the back pressure of the turbine is higher than the set back pressure and the opening of the first regulating valve 73 is maximum. The temperature of the steam in the secondary hot steam pipe 80 is higher than the temperature of the continuous exhaust steam of the deaerator in the deaerator exhaust heating pipe 70. The secondary heat exchanger 90 is arranged between the primary heat exchanger 60 and the ejector 50. The air supply pipe 40 exchanges heat with the secondary hot steam pipe 80 through the secondary heat exchanger 90. The gas in the air supply pipe 40 is first heated by the primary heat exchanger 60 to increase its temperature for the first time, and then exchanges heat with the secondary heat exchanger 90 to further increase its temperature, thereby increasing the temperature of the gas ejected from the ejector 50.

[0083] Preferably, the antifreeze device also includes a first temperature detector 44 and a second temperature detector 45. The first temperature detector 44 is located between the first heat exchanger 60 and the second heat exchanger 90, and is used to detect the temperature of the gas heated once by the first heat exchanger 60. The second temperature detector 45 is located between the second heat exchanger 90 and the ejector 50, and is used to detect the temperature of the gas heated for the second time by the second heat exchanger 90, that is, the temperature of the gas flowing to the ejector 50; a second regulating valve 82 is provided on the second hot steam pipe 80, and the first temperature detector 44 and the second temperature detector 45 are respectively connected to the control module, and are used to adjust the deaerator continuous exhaust flow in the deaerator exhaust heating pipe 70 and the steam flow in the second hot steam pipe 80 based on the detected temperature, so that the gas temperature in the gas supply pipe 40 reaches the required temperature.

[0084] As attached Figure 5As shown, the air jet 50 of this embodiment includes a first nozzle 51 and a second nozzle 52. The spray range of the second nozzle 52 is larger than the spray range of the first nozzle 51. The control module is connected to the air jet 50 and is used to select to open the first nozzle 51 or the second nozzle 52 or to open the first nozzle 51 and the second nozzle 52 at the same time based on the condensate temperature. That is, when the condensate temperature is low, the first nozzle 51 is opened. The first nozzle 51 is relatively closer to the condensing unit 11, and the spray range is smaller, but more accurate, and the gas temperature loss is less. When the condensate temperature is lower, the first nozzle 51 is closed and the second nozzle 52 is opened. Although the second nozzle 5 2 is relatively far away from the condensing unit 11, but the spray range of the second nozzle 52 is larger, and the gas temperature in the gas supply pipe 40 is higher at this time. Therefore, the gas temperature sprayed by the second nozzle 52 is higher, which can create a warmer environment and increase the temperature of the specific part of the condensing unit 11; when the condensate temperature drops further, indicating that the ambient temperature is even lower and there may be strong winds, the first nozzle 51 and the second nozzle 52 are opened at the same time. The gas sprayed by the second nozzle 52 is shielded by the gas sprayed by the first nozzle 51 to form a gas shield, which is conducive to retaining heat, reducing gas temperature loss, and better heating effect on the condensing unit 11.

[0085] As attached Figure 6 As shown, at least two ejectors 50 are correspondingly provided for a downstream tube bundle 111, and at least two ejectors 50 are correspondingly provided for a countercurrent tube bundle 112; when the first nozzle 51 and the second nozzle 52 need to be opened simultaneously, the condensate temperature and the ambient temperature are very low, and the ejected gas is easy to cool down quickly in such a cold environment. Therefore, in two adjacent ejectors 50, the ejection ranges of the two second nozzles 52 partially overlap, and the ejection range of the second nozzle 52 contacts or partially overlaps with the edge of the ejection range of the first nozzle 51 of the other ejector 50, thereby forming a multi-layer gas barrier, so that the gas temperature within the total ejection range of the ejector 50 is relatively uniform, and heat is not easily lost, which has a good heating effect on the condensing unit 11.

[0086] For the downstream tube bundle 111 located at the edge of the condensing unit 11, the spraying range of the second nozzle 52 provided in this embodiment exceeds the edge of the downstream tube bundle 111. Therefore, even if the hot air sprayed from the second nozzle 52 is affected by the ambient wind and moves toward the inside of the air-cooling island 10, it can be ensured that the edge of the downstream tube bundle 111 is within the spraying range of the second nozzle 52, so as to avoid the occurrence of local freezing and blockage of the downstream tube bundle 111.

[0087] The ejectors 50 corresponding to each column of the downstream tube bundle 111 or the countercurrent tube bundle 112 can be independently regulated. The ejection range of each ejector 50 is controlled according to the temperature detected by the temperature sensor 14 corresponding to each column of the downstream tube bundle 111 or the countercurrent tube bundle 112. That is, each ejector 50 can be controlled to individually open the first nozzle 51 or the second nozzle 52 or to open the first nozzle 51 and the second nozzle 52 at the same time, so as to eject more hot gas to a colder part, thereby achieving precise heating and improving heat utilization.

[0088] Specifically, a first regulating valve 53 is provided on the connecting pipe between the first nozzle 51 and the air supply pipe 40, and a second regulating valve 54 is provided on the connecting pipe between the second nozzle 52 and the air supply pipe 40. The first regulating valve 53 and the second regulating valve 54 are both electrically controlled valves, which are communicatively connected to the control module to realize remote selection and control of the injector 50.

[0089] The air supply pipeline 40 includes an air compressor 41. The gas in the air supply pipeline 40 is compressed air. The air compressor 41 is an adjustable pressure air compressor 41. The control module is in communication with the air compressor 41 and is used to adjust the pressure of the air compressor 41 based on the condensate temperature. When only the first nozzle 51 is turned on, the pressure of the air compressor 41 can be a first pressure. When only the second nozzle 52 is turned on, the pressure of the air compressor 41 needs to be increased to a second pressure due to the larger spray range and higher gas flow rate. When the first nozzle 51 and the second nozzle 52 are turned on simultaneously, the pressure of the air compressor 41 needs to be further increased to a third pressure. The specific data of the first pressure, the second pressure, and the third pressure are set according to the diameter of the air supply pipeline and the size of the nozzle.

[0090] When the on-off unit 81 of the secondary hot steam pipe 80 is turned on, at this time, the pressure of the air compressor 41 is greater than or equal to the third pressure, the gas flow rate in the air supply pipe 40 increases, and the contact time with the primary heat exchanger 60 is reduced, while the deaerator continuous exhaust flow in the deaerator exhaust heating pipe 70 cannot be further increased. Therefore, the first temperature detector 44 detects a slight decrease in temperature, and the second regulating valve 82 on the secondary hot steam pipe 80 can be controlled to open more. The secondary heat exchanger 90 can further increase the gas temperature in the air supply pipe 40, thereby improving the heating effect on the condensing unit 11.

[0091] To facilitate maintenance, the antifreeze system of this embodiment includes several isolation valves. Specifically, a first isolation valve 71 is provided on the exhaust steam heating pipe of the deaerator. The first isolation valve 71 is located between the inlet of the primary heat exchanger and the exhaust steam heating pipe of the deaerator; a second isolation valve 72 is provided on the exhaust steam heating pipe of the deaerator. The second isolation valve 72 is located between the terminal of the primary heat exchanger and the exhaust steam heating pipe of the deaerator; a third isolation valve 42 is provided on the gas supply pipeline. The third isolation valve 42 is located between the starting end of the gas supply pipeline and the primary heat exchanger; the gas supply pipeline A fourth isolation valve 43 is provided on it, and the fourth isolation valve 43 is located between the first-level heat exchanger and the second-level heat exchanger; a fifth isolation valve 46 is provided on the gas supply pipeline, and the fifth isolation valve 46 is located between the second-level heat exchanger and the terminal of the gas supply pipeline; a sixth isolation valve 83 is provided on the second-level hot steam pipe, and the sixth isolation valve 83 is located upstream of the second-level heat exchanger; a seventh isolation valve 84 is provided on the second-level hot steam pipe, and the seventh isolation valve 84 is located downstream of the second-level heat exchanger; an eighth isolation valve 34 is provided on the pipeline between the multi-stage water seal 33 and the unit hot well.

[0092] Based on the antifreeze system of this embodiment, the present invention further provides an antifreeze method for an air-cooled unit based on continuous exhaust steam waste heat from a deaerator, comprising the following steps:

[0093] Open the deaerator exhaust steam heating pipe to draw out at least part of the deaerator continuous exhaust steam from the deaerator continuous exhaust steam pipe 30;

[0094] Open the gas supply pipeline. The gas in the gas supply pipeline passes through the first-stage heat exchanger and exchanges heat with the exhaust steam of the deaerator to increase the gas temperature. The exhaust steam of the deaerator condenses into water.

[0095] The ejector is started, and the gas with a raised temperature is injected onto the lower end of the downstream tube bundle 111 and the upper end of the countercurrent tube bundle 112, thereby heating the lower end of the downstream tube bundle 111 and the upper end of the countercurrent tube bundle 112 from the outside.

[0096] Preferably, the method of this embodiment further includes:

[0097] Detecting the condensate temperature in the condensate header 12 at the lower end of the downstream tube bundle 111, and controlling the gas temperature and injection range of the ejector corresponding to the lower end of the downstream tube bundle 111 according to the condensate temperature in the condensate header 12;

[0098] The condensate temperature of the vacuum header 131 at the upper end of the counter-flow tube bundle 112 is detected, and the gas temperature and injection range of the ejector corresponding to the upper end of the counter-flow tube bundle 112 are controlled according to the condensate temperature of the vacuum header 131 .

[0099] Specifically, the control logic of the gas temperature and injection range of the injector is as follows:

[0100] If the condensate temperature is lower than the first set value T1, the first regulating valve 73 on the deaerator exhaust steam heating pipe is opened, the air compressor on the air supply pipe is turned on, and the first nozzle is turned on to heat the lower end of the downstream tube bundle 111 and / or the upper end of the countercurrent tube bundle 112;

[0101] If the condensate temperature is lower than the second set value T2, the opening of the first regulating valve 73 on the deaerator exhaust steam heating pipe is increased to increase the continuous exhaust steam flow of the deaerator in the deaerator exhaust steam heating pipe, and the pressure of the air compressor on the air supply pipeline is increased. The first nozzle is closed and the second nozzle is opened to heat the lower end of the downstream tube bundle 111 and / or the upper end of the countercurrent tube bundle 112;

[0102] If the condensate temperature is lower than the third set value T3, the first regulating valve 73 on the deaerator exhaust steam heating pipe is opened to the maximum, the continuous exhaust steam flow of the deaerator in the deaerator exhaust steam heating pipe is increased, the pressure of the air compressor on the air supply pipe is increased, the first nozzle is opened, and the second nozzle is opened to heat the lower end of the downstream tube bundle 111 and / or the upper end of the countercurrent tube bundle 112;

[0103] If the condensate temperature is lower than the fourth set value T4, and the back pressure of the steam turbine is detected to be higher than the set back pressure, the secondary hot steam pipe is opened to increase the pressure of the air compressor on the air supply pipe. The gas in the air supply pipe passes through the primary heat exchanger and the secondary heat exchanger in sequence for secondary heating. The first nozzle is opened and the second nozzle is opened to heat the lower end of the downstream tube bundle 111 and / or the upper end of the countercurrent tube bundle 112.

[0104] T1 to T4 can be set according to the following rules: T1>T2>T3>T4. The specific values ​​are set by the actual environment and operating conditions of the unit.

[0105] Example 2

[0106] The air-cooled unit of this embodiment is an indirect air-cooled unit. Exhaust steam from the steam turbine of the thermal power generator is discharged to an indirect air-cooled unit located outdoors via an exhaust pipe. The indirect air-cooled unit includes a condenser and an intercooling tower 20. The exhaust pipe connects the exhaust port of the steam turbine to the condenser. A first circulation loop is provided between the condenser and the intercooling tower 20. The circulating medium may be water. Heat from the high-temperature circulating medium is transferred to the low-temperature circulating medium, which then becomes high-temperature circulating medium. The low-temperature circulating medium then flows back to the intercooling tower 20, where it is cooled to low-temperature circulating medium before flowing back to the condenser. The high-temperature circulating medium is cooled in the intercooling tower primarily by a cooling triangle radiator 21, which is generally located around the outer periphery of the intercooling tower. The circulation loop is connected to the cooling triangle radiator. When cold air passes through the cooling triangle radiator, heat exchange occurs. The resulting hot air is discharged upward from the center of the intercooling tower. The high-temperature circulating medium is cooled to low-temperature circulating medium in the cooling triangle radiator.

[0107] Based on this, the difference between this embodiment and the first embodiment is that the low-temperature region of the air-cooled unit in this embodiment exists in the cooling triangle radiator. Specifically, the cooling triangle radiator 21 has a connected water inlet pipe 23 and a return pipe 22, and the lower end of the return pipe 22 is the low-temperature region. The low-temperature region temperature detection module in the indirect air-cooled unit includes a temperature sensor 14 at the lower end of the return pipe 22, which detects the return water temperature at a location prone to freezing. This module is referred to as a return water temperature detection module. Several jets correspond to the several cooling triangle radiators of the indirect cooling tower, and the jets are oriented toward the lower end of the return pipe. The antifreeze device is controlled based on the return water temperature.

[0108] As attached Figure 8 and attached Figure 9 As shown, since the return pipe 22 is generally arranged vertically, multiple air jets 50 can be arranged in an up-and-down arrangement, with at least two air jets 50 disposed at the lower end of a return pipe 22. Controlled by the control module, they are activated sequentially from bottom to top based on the return water temperature. The activation priority of all first nozzles 51 and second nozzles 52 of air jets 50 at the same height is higher than the activation priority of all first nozzles 51 and second nozzles 52 of air jets 50 at a higher height. The spray ranges of two adjacent second nozzles 52 partially overlap, and the spray range of the second nozzle 52 of one air jet 50 touches or partially overlaps the edge of the spray range of the first nozzle 51 of the other air jet 50.

[0109] Based on this, the antifreeze method of this embodiment is also different from that of embodiment 1. When the air-cooling unit is an indirect air-cooling unit, the antifreeze device adopts the following control logic:

[0110] Detecting the return water temperature at the lower end of the return water pipe 22, and controlling the gas temperature and injection range of the corresponding injector 50 according to the return water temperature;

[0111] If the return water temperature is lower than the first set value T1, the first regulating valve 73 on the deaerator exhaust steam heating pipe 70 is opened, the air compressor 41 on the air supply pipe 40 is turned on, and the first nozzle 51 in the air injector at the lower end of the return water pipe 22 is turned on to heat the lower end of the return water pipe 22;

[0112] If the return water temperature is lower than the second set value T2, the opening of the first regulating valve 73 on the deaerator exhaust steam heating pipe 70 is increased to increase the continuous exhaust steam flow of the deaerator in the deaerator exhaust steam heating pipe 70, and the pressure of the air compressor 41 on the air supply pipe 40 is increased. The first nozzle 51 in the air injector at the lower end of the return water pipe 22 is closed, and the second nozzle 52 is opened to heat the lower end of the return water pipe 22.

[0113] If the return water temperature is lower than the third set value T3, the first regulating valve 73 on the deaerator exhaust steam heating pipe 70 is adjusted to the maximum opening, increasing the deaerator continuous exhaust steam flow in the deaerator exhaust steam heating pipe 70, increasing the pressure of the air compressor 41 on the air supply pipe 40, and simultaneously opening the first nozzle 51 and the second nozzle 52 in the air injector at the lowest end of the return water pipe 22 to heat the lowest end of the return water pipe 22;

[0114] If the return temperature is lower than the fourth set value T4 and the back pressure of the steam turbine is detected to be higher than the set back pressure, the secondary hot steam pipe is opened to increase the pressure of the air compressor 41 on the air supply pipe 40. The gas in the air supply pipe 40 passes through the primary heat exchanger 60 and the secondary heat exchanger 90 in sequence for secondary heating. At the same time, the first nozzle 51 and the second nozzle 52 of at least two groups of nozzles located at the height of the lower end of the return pipe 22 are opened to heat the middle and lower end of the return pipe 22.

[0115] After the set time, if it is detected that the back pressure of the steam turbine is lower than the set back pressure and the return water temperature is still lower than the fourth set value, it will continue to be maintained until the return water temperature is higher than the fourth set value.

[0116] T1, T2, T3, and T4 in this embodiment may be the same as those in the first embodiment, or may be reset according to the actual temperature of the indirect air-cooling unit in this embodiment, ensuring that the following conditions are met: T1>T2>T3>T4, and the specific values ​​are set by the actual environment and operating conditions of the unit.

[0117] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. An air-cooling unit antifreeze system based on continuous exhaust steam waste heat from a deaerator, characterized in that: It includes a deaerator continuous exhaust pipe, an air cooling unit and an antifreeze device, wherein the deaerator continuous exhaust pipe is connected to the continuous exhaust port of the deaerator; The antifreeze device includes an air supply pipe, an air jet, a primary heat exchanger, and a deaerator exhaust steam heating pipe connected to the deaerator continuous exhaust pipe, the deaerator exhaust steam heating pipe is used to lead all the deaerator continuous exhaust steam from the deaerator continuous exhaust pipe, the air supply pipe exchanges heat with the deaerator exhaust steam heating pipe through the primary heat exchanger to increase the gas temperature in the air supply pipe, the air jet is arranged at the terminal end of the air supply pipe, and several of the air jets are arranged in the low-temperature area of ​​the air-cooling unit, and the nozzles of the air jets spray the heated gas toward the low-temperature area; When the air-cooling unit is a direct air-cooling unit, the direct air-cooling unit includes an air-cooling island and a condensate tank. The air-cooling island is connected to the steam turbine through an exhaust pipe. The air-cooling island includes a plurality of triangular cooling units. The triangular cooling unit is in an inverted "V" shape and includes two inclined condensing units. The condensing unit includes a downstream tube bundle and a countercurrent tube bundle. The downstream tube bundle is connected to the condensate tank. The plurality of ejectors are located between the two inclined condensing units and are respectively located at the lower end of the downstream tube bundle and the upper end of the countercurrent tube bundle. The lower end of the downstream tube bundle and the upper end of the countercurrent tube bundle are low-temperature areas. The low-temperature area temperature detection module includes a temperature sensor located in the condensate manifold at the lower end of the downstream tube bundle and a temperature sensor located in the vacuum manifold at the upper end of the countercurrent tube bundle.

2. The air cooling unit antifreeze system according to claim 1, characterized in that: It also includes a control module and several low-temperature area temperature detection modules. The low-temperature area temperature detection modules are dispersedly arranged in the tube bundle of the low-temperature area of ​​the air-cooling unit and are communicatively connected to the control module. The control module is communicatively connected to the antifreeze device and is used to control the gas temperature in the air supply pipeline and the injection range of the injector based on the temperature of the low-temperature area.

3. The air cooling unit antifreeze system according to claim 2, characterized in that: The antifreeze device also includes a secondary hot steam pipe and a secondary heat exchanger connected to the heat source. The temperature of the steam in the secondary hot steam pipe is higher than the temperature of the deaerator continuous exhaust steam in the deaerator exhaust heating pipe. The secondary heat exchanger is arranged between the primary heat exchanger and the ejector. The air supply pipeline exchanges heat with the secondary hot steam pipe through the secondary heat exchanger.

4. The air cooling unit antifreeze system according to claim 3, characterized in that: The deaerator exhaust steam heating pipe is provided with a first regulating valve; the control module is communicatively connected to the first regulating valve, and is used to adjust the deaerator continuous exhaust steam flow in the deaerator exhaust steam heating pipe based on the temperature of the low temperature area; The antifreeze system further includes a back pressure detection module for detecting the back pressure of the steam turbine, the back pressure detection module being communicatively connected to the control module; an on-off unit is provided on the secondary hot steam pipe, the on-off unit being communicatively connected to the control module and being configured to open the secondary hot steam pipe when the back pressure of the steam turbine is higher than a set back pressure and the opening of the first regulating valve is at its maximum; The secondary hot steam pipe is provided with a second regulating valve for regulating the gas temperature in the gas supply pipe based on the temperature of the low-temperature area.

5. The air cooling unit antifreeze system according to claim 3, characterized in that: The antifreeze device also includes a first temperature detector and a second temperature detector, the first temperature detector is located between the first-level heat exchanger and the second-level heat exchanger, and the second temperature detector is located between the second-level heat exchanger and the ejector. The first temperature detector and the second temperature detector are respectively connected to the control module, and are used to adjust the deaerator continuous exhaust flow in the deaerator exhaust heating pipe and the steam flow in the second-level hot steam pipe based on the detected temperature.

6. The air cooling unit antifreeze system according to claim 3, characterized in that: The terminal end of the deaerator exhaust heating pipe is connected to the condensate recovery tank, and the condensate recovery tank is connected to the unit hot well through a multi-stage water seal. The condensate recovery tank is provided with a drain pipe and a drain pipe isolation valve; The terminal end of the secondary hot steam pipe is communicated with the condensate recovery tank.

7. The air cooling unit antifreeze system according to any one of claims 2 to 6, characterized in that: The air cooling unit is an indirect air cooling unit or a direct air cooling unit; When the air-cooling unit is an indirect air-cooling unit, the indirect air-cooling unit includes an intercooling tower and a condenser. The condenser is connected to the turbine through an exhaust pipe, and the intercooling tower is connected to the condenser through a circulation pipeline. The intercooling tower includes a plurality of cooling triangle radiators. The cooling triangle radiators have a connected water inlet pipe and a return pipe inside. The water inlet pipe and the return pipe are respectively connected to the circulation pipeline. The lower end of the return pipe is a low-temperature area. The plurality of jets correspond to the plurality of cooling triangle radiators of the intercooling tower, and the jet direction of the jet is toward the lower end of the return pipe; the low-temperature area temperature detection module includes a temperature sensor located at the lower end of the return pipe.

8. The air cooling unit antifreeze system according to claim 7, characterized in that: The air supply pipeline includes an air compressor, the gas in the air supply pipeline is compressed air, the air compressor is an adjustable pressure air compressor, and the control module is in communication with the air compressor and is used to adjust the pressure of the air compressor based on the temperature of the low temperature area; The sprayer includes a first nozzle and a second nozzle, the spray range of the second nozzle is larger than the spray range of the first nozzle, and the control module is connected to the sprayer and is used to select to open the first nozzle or the second nozzle or open the first nozzle and the second nozzle at the same time based on the temperature of the low-temperature area; When the air-cooling unit is a direct air-cooling unit, at least two of the injectors are correspondingly provided for one downstream tube bundle, and at least two of the injectors are correspondingly provided for one upstream tube bundle; In two adjacent air jets, the spraying ranges of the two second nozzles partially overlap, and the spraying range of the second nozzle touches or partially overlaps with the edge of the spraying range of the first nozzle of the other air jet; The spray range of the second nozzle of the injector close to the edge of the downstream tube bundle exceeds the edge of the downstream tube bundle; When the air-cooling unit is an indirect air-cooling unit, the plurality of injectors are vertically arranged at positions corresponding to the low-temperature area of ​​the cooling triangle radiator and the lower end of the return water pipe, and are controlled by the control module to be opened in sequence from bottom to top based on the return water temperature; the opening priority of all the first nozzles and the second nozzles of the injectors at the same height is higher than the opening priority of all the first nozzles and the second nozzles of the injectors at a higher height; The spraying ranges of two upper and lower adjacent second nozzles partially overlap, and the spraying range of the second nozzle of one of the nozzles contacts or partially overlaps with the edge of the spraying range of the first nozzle in the other nozzle.

9. A method for antifreezing an air-cooling unit based on continuous exhaust heat from a deaerator, characterized in that: The antifreeze system according to any one of claims 1 to 8 comprises the following steps: Opening the deaerator exhaust steam heating pipe to draw out at least a portion of the deaerator continuous exhaust steam from the deaerator continuous exhaust steam pipeline; Open the gas supply pipeline. The gas in the gas supply pipeline passes through the first-stage heat exchanger and exchanges heat with the exhaust steam of the deaerator to increase the gas temperature. The exhaust steam of the deaerator condenses into water. The ejector is started, and the gas with the increased temperature is injected into the low temperature area of ​​the air cooling unit.

10. The antifreeze method for an air cooling unit according to claim 9, characterized in that: When the air-cooling unit is a direct air-cooling unit, the antifreeze device adopts the following control logic: Detecting the condensate temperature in the condensate header at the lower end of the downstream tube bundle, and controlling the gas temperature and injection range of the injector corresponding to the lower end of the downstream tube bundle according to the condensate temperature in the condensate header; Detecting the condensate temperature of the vacuum header at the upper end of the counter-flow tube bundle, and controlling the gas temperature and injection range of the ejector corresponding to the upper end of the counter-flow tube bundle according to the condensate temperature of the vacuum header; If the condensate temperature is lower than the first set value, the first regulating valve on the exhaust steam heating pipe of the deaerator is opened, the air compressor on the air supply pipe is turned on, and the first nozzle is turned on to heat the lower end of the downstream tube bundle and / or the upper end of the countercurrent tube bundle; If the condensate temperature is lower than the second set value, the opening of the first regulating valve on the deaerator exhaust steam heating pipe is increased to increase the continuous exhaust steam flow of the deaerator in the deaerator exhaust steam heating pipe, increase the pressure of the air compressor on the air supply pipeline, close the first nozzle, and open the second nozzle to heat the lower end of the downstream tube bundle and / or the upper end of the countercurrent tube bundle; If the condensate temperature is lower than the third set value, the first regulating valve on the deaerator exhaust steam heating pipe is adjusted to the maximum opening, the deaerator continuous exhaust steam flow in the deaerator exhaust steam heating pipe is increased, the pressure of the air compressor on the air supply pipe is increased, the first nozzle is opened, the second nozzle is opened, and the lower end of the downstream tube bundle and / or the upper end of the countercurrent tube bundle is heated; If the condensate temperature is lower than the fourth set value and the back pressure of the steam turbine is detected to be higher than the set back pressure, the secondary hot steam pipe is opened to increase the pressure of the air compressor on the air supply pipe. The gas in the air supply pipe passes through the primary heat exchanger and the secondary heat exchanger in sequence for secondary heating. The first nozzle is opened and the second nozzle is opened to heat the lower end of the downstream tube bundle and / or the upper end of the countercurrent tube bundle. When the air-cooling unit is an indirect air-cooling unit, the antifreeze device adopts the following control logic: Detect the return water temperature at the lower end of the return water pipe, and control the gas temperature and injection range of the corresponding injector according to the return water temperature; If the return water temperature is lower than the first set value, the first regulating valve on the exhaust steam heating pipe of the deaerator is opened, the air compressor on the air supply pipe is turned on, and the first nozzle in the air injector at the lowest end of the return water pipe is turned on to heat the lowest end of the return water pipe; If the return water temperature is lower than the second set value, the opening of the first regulating valve on the deaerator exhaust steam heating pipe is increased to increase the continuous exhaust steam flow of the deaerator in the deaerator exhaust steam heating pipe, increase the pressure of the air compressor on the air supply pipe, close the first nozzle of the air injector at the bottom end of the return water pipe, and open the second nozzle to heat the bottom end of the return water pipe; If the return water temperature is lower than the third set value, the first regulating valve on the deaerator exhaust steam heating pipe is adjusted to the maximum opening, the continuous exhaust steam flow of the deaerator in the deaerator exhaust steam heating pipe is increased, the pressure of the air compressor on the air supply pipe is increased, and the first nozzle and the second nozzle of the air injector at the lower end of the return water pipe are opened at the same time to heat the lower end of the return water pipe; If the return water temperature is lower than the fourth set value and the back pressure of the steam turbine is detected to be higher than the set back pressure, the secondary hot steam pipe is opened to increase the pressure of the air compressor on the air supply pipe. The gas in the air supply pipe passes through the primary heat exchanger and the secondary heat exchanger in sequence for secondary heating. At the same time, the first and second nozzles of at least two groups of nozzles located at the height direction of the lower end of the return water pipe are opened to heat the middle and lower end of the return water pipe. After the set time, if it is detected that the back pressure of the steam turbine is lower than the set back pressure and the return water temperature is still lower than the fourth set value, it will continue to be maintained until the return water temperature is higher than the fourth set value.

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