System and method for increasing secondary air temperature

Abstract

The invention provides a system and method for increasing the temperature of secondary air, and relates to the technical field of steam turbines, the system comprises an assembly structure and a control system, the assembly structure comprises an air feeder, an air pre-heater, a hot secondary air heat exchanger and a hot secondary air bellow, the output end of the air feeder is connected with the air pre-heater, and the output end of the air pre-heater is connected with the hot secondary air heat exchanger; the output end of the hot secondary air heat exchanger is connected with a hot secondary air box, and a heat source opening of the secondary air heat exchanger is connected with triple extraction steam through a main pipeline. The triple-extraction steam is led to the hot secondary air heat exchanger to heat the hot secondary air and then returns to the external steam cooler and the # 3 high-pressure heater to heat and supply water, and the steam parameters of the triple-extraction steam entering the external steam cooler and the # 3 high-pressure heater are reduced, so that the steam-water side temperature difference of the # 3 high-pressure heater is reduced, the heat exchange environment of the high-pressure heater is ensured, and the heat exchange efficiency of the high-pressure heater is improved. And the temperature of the part is used for further increasing the hot secondary air temperature, coal consumption is reduced, and the combustion efficiency of the boiler is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of steam turbines, and in particular to a system and method for increasing secondary air temperature. Background Art

[0002] Steam turbine, also known as steam turbine engine, is a rotary steam power device that uses high-temperature and high-pressure steam as a power source. Its working principle is that high-temperature and high-pressure steam is reduced in pressure, increased in speed, and turned through the nozzle chamber to form a high-speed airflow that is sprayed onto the blades, driving the rotor equipped with blade rows to rotate, thereby converting the thermal energy of the steam into mechanical energy. Steam turbines are widely used in modern thermal power plants, as well as in metallurgy, chemical industry, and ship power devices. It is mainly composed of two parts: the stator and the rotor. The stator includes components such as the cylinder, partition, and static blade grid, while the rotor includes rotating components such as the main shaft, impeller, and moving blades. Steam turbines have the advantages of high single-unit power, high efficiency, and long life, and are an indispensable and important equipment in modern industry. The steam turbine tertiary extraction is connected after the 7th stage of the intermediate pressure cylinder, and enters the #3 high pressure heater to heat the feed water after passing through the external steam cooler. During operation, the #3 high pressure heater inlet steam temperature overheats, and the difference between the #3 high pressure heater inlet steam temperature and the feed water temperature is the largest, which can easily lead to leakage of the #3 high pressure heater. Therefore, the present invention proposes a system and method for increasing the secondary air temperature to solve the problems existing in the prior art. Summary of the invention

[0003] In view of the above problems, the present invention proposes a system and method for increasing the temperature of secondary air. The system and method for increasing the temperature of secondary air lead the tertiary extraction steam to the hot secondary air heat exchanger to heat the hot secondary air, and then return it to the external steam cooler and #3 high pressure heater to heat the feed water. The steam parameters of the tertiary extraction steam entering the external steam cooler and #3 high pressure heater are reduced, thereby reducing the temperature difference between the steam and water sides of the #3 high pressure heater, ensuring the heat exchange environment of the high pressure heater, and using this part of the temperature to further increase the temperature of the hot secondary air, reduce coal consumption, and improve boiler combustion efficiency.

[0004] To achieve the purpose of the present invention, the present invention is implemented through the following technical solutions: a system for increasing the temperature of secondary air, including a component structure and a control system, the component structure including an air blower, an air preheater, a hot secondary air heat exchanger and a hot secondary air box, the output end of the air blower is connected to the air preheater, and the output end of the air preheater is connected to the hot secondary air heat exchanger, the output end of the hot secondary air heat exchanger is connected to the hot secondary air box, the heat source port of the secondary air heat exchanger is connected to three-extraction steam through a main pipeline, and the heat source port of the secondary air heat exchanger is connected to an external steam cooler, and a steam bypass pipeline is added between the three-extraction steam and the external steam cooler; The control system includes a data acquisition module, a temperature difference calculation module and a compensation module. The acquisition module is used to collect the real-time temperature of the current three-extraction steam. The temperature difference calculation module is used to calculate the load value for controlling the temperature of the three-extraction steam according to the preset three-extraction steam specified temperature. Therefore, the connection of the main pipeline or the steam bypass pipeline is first switched, and then the heat exchange source amount supplied by other sources of the hot secondary air heat exchanger or the air supply amount of the blower is adjusted to control the temperature of the three-extraction steam to the specified temperature. The compensation module is used to compensate for the error after the temperature difference calculation module is adjusted multiple times.

[0005] Further improvements are: a first electromagnetic regulating valve is provided on the steam bypass pipeline, a second electromagnetic regulating valve is provided on the main pipeline, and the heat source ports of the secondary air heat exchanger are provided with multiple groups, one group of heat source ports is connected to the main pipeline, and the heat source ports of other groups are connected to other supplied heat sources.

[0006] A further improvement is that: the blower, air preheater and hot secondary air heat exchanger are provided in multiple groups, and the output ends of the multiple groups of hot secondary air heat exchangers are connected to the hot secondary air box.

[0007] A further improvement is that the data acquisition module includes a temperature sensor, an air volume sensor, a three-extraction steam flow sensor and a storage module. The temperature sensor and the three-extraction steam flow sensor are used to collect the current temperature and flow of the three-extraction steam, and the air volume sensor is used to collect the air volume of the blower.

[0008] A further improvement is that the other heat exchange sources supplied by the hot secondary air heat exchanger are from a flow collection interface, and the data output end of the flow collection interface is connected to a storage module. The storage module is also used to connect a temperature sensor, an air volume sensor, and a three-extraction steam flow sensor to store real-time collected data and timestamp it. The storage module is connected to a human-computer interaction terminal to provide a data retrieval function.

[0009] Further improvements are: the temperature difference calculation module includes a threshold setting module, a mode switching module and a calculation control module, the threshold setting module is used to connect to the human-computer interaction terminal, and provides the operator with the function of setting the temperature threshold for the three-extraction steam control, the mode switching module has a built-in comparison algorithm, and the mode switching module is connected to the storage module, and the real-time collected three-extraction steam temperature is compared with the set temperature threshold to determine whether the three-extraction steam temperature needs to be regulated. When it is determined that it is necessary, the main pipeline is opened and the steam bypass pipeline is closed. When it is determined that it is not necessary, the steam bypass pipeline is opened and the main pipeline is closed.

[0010] A further improvement is that the calculation and control module is used to trigger the start when it is determined that the temperature of the triple-extraction steam needs to be regulated, and the calculation and control module first identifies the current operating parameters of the overall steam turbine system, determines the real-time adjustable parameters and non-adjustable parameters of the system, and when the real-time heat exchange source quantity supplied by the hot secondary air heat exchanger of the system is not adjustable, the air supply volume of the blower is adjusted, and the heat exchange difference of the air supply volume is used to adjust the temperature of the triple-extraction steam.

[0011] A further improvement is that when the real-time air volume required by the hot secondary air box of the system is fixed, it is determined that the air volume of the current blower cannot be adjusted, so the amount of other heat sources supplied by the hot secondary air heat exchanger is adjusted, and the heat supply difference of other heat sources is used to adjust the temperature of the three-extraction steam.

[0012] A further improvement is that the compensation module has a built-in compensation algorithm, and the compensation module is connected to the external steam cooler, so as to collect the temperature of the three-extraction steam entering the external steam cooler after each regulation of the temperature difference calculation module, compare the temperature with the target temperature value regulated by the temperature difference calculation module, calculate the difference through the compensation algorithm, and apply the difference to the actual calculation of the calculation control module to perform regulation compensation.

[0013] A method for increasing the temperature of secondary air comprises the following steps: Connect the blower, air preheater, hot secondary air heat exchanger and hot secondary air box for air supply; The three-extraction steam is led to the hot secondary air heat exchanger through the main pipeline to heat the delivered air; Through the real-time overall dispatching system parameters of the control system, the temperature of the steam after heat exchange of the third extraction is controlled to reach the specified threshold; After the three-extraction steam has undergone heat exchange, it enters the external steam cooler for cooling, and then enters the #3 high-pressure heater for heating water supply; A steam bypass pipeline is added between the triple-extraction steam and the external steam cooler to adjust and switch according to the actual high and low loads and failures of the hot secondary air heat exchanger.

[0014] The beneficial effects of the present invention are: 1. The present invention introduces the tertiary extraction steam to the hot secondary air heat exchanger to heat the hot secondary air, and then returns it to the external steam cooler and the #3 high-pressure heater to heat the feed water. The steam parameters of the tertiary extraction steam entering the external steam cooler and the #3 high-pressure heater are reduced, thereby reducing the temperature difference between the steam and water sides of the #3 high-pressure heater, ensuring the heat exchange environment of the high-pressure heater, and using this part of the temperature to further increase the hot secondary air temperature, reduce coal consumption, and improve boiler combustion efficiency.

[0015] 2. The present invention adds a steam bypass pipeline, which can allow the three-extraction steam to circulate without passing through the hot secondary air heat exchanger when the three-extraction steam does not need to be regulated, thereby reducing unnecessary load. It can also switch when the hot secondary air heat exchanger fails, thereby improving the safety and stability of the system and reducing the standard coal consumption for power generation.

[0016] 3. The present invention can collect data through the control system, and cut the main pipeline and the steam bypass pipeline according to whether the temperature of the three-extraction steam needs to be regulated. When it is determined that regulation is needed, the real-time adjustable parameters and non-adjustable parameters of the system are collected, thereby adjusting the air supply volume of the blower or the heat exchange source volume of other supplies of the hot secondary air heat exchanger as needed, so as to achieve the purpose of accurately controlling the temperature of the three-extraction steam, and through the compensation module, the possible errors in the calculation after multiple adjustments are compensated, thereby further improving the accuracy of controlling the temperature of the three-extraction steam. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the component structure of the present invention; Figure 2 It is a schematic diagram of the method flow of the present invention. DETAILED DESCRIPTION

[0018] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with examples. The examples are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0019] Embodiment 1 according to Figure 1 , 2 As shown, this embodiment proposes a system for increasing the temperature of secondary air, including a component structure and a control system, wherein the component structure includes an air blower, an air preheater, a hot secondary air heat exchanger and a hot secondary air box, wherein the output end of the air blower is connected to the air preheater, and the output end of the air preheater is connected to the hot secondary air heat exchanger, and the output end of the hot secondary air heat exchanger is connected to the hot secondary air box, the heat source port of the secondary air heat exchanger is connected to the three-extraction steam through the main pipeline, and the heat source port of the secondary air heat exchanger is connected to the external steam cooler, and a steam bypass pipeline is additionally provided between the three-extraction steam and the external steam cooler; The control system includes a data acquisition module, a temperature difference calculation module and a compensation module. The acquisition module is used to collect the real-time temperature of the current three-extraction steam. The temperature difference calculation module is used to calculate the load value of the temperature of the three-extraction steam according to the preset three-extraction steam specified temperature, thereby first switching the connection of the main pipeline or the steam bypass pipeline, and then adjusting the heat exchange source amount supplied by the hot secondary air heat exchanger or the air supply amount of the blower, and controlling the temperature of the three-extraction steam to the specified temperature. The compensation module is used to compensate for the error after the temperature difference calculation module is adjusted multiple times. When in use, the three-extraction steam is led to the hot secondary air heat exchanger to heat the hot secondary air, and then returned to the external steam cooler and #3 high-pressure heating to heat the water supply. The steam parameters of the three-extraction steam entering the external steam cooler and #3 high-pressure heating are reduced, thereby reducing the temperature difference on the steam-water side of #3 high-pressure heating, ensuring the high-pressure heating heat exchange environment, and using this part of the temperature to further increase the hot secondary air temperature, reduce coal consumption, and improve boiler combustion efficiency.

[0020] The steam bypass pipeline is provided with a first electromagnetic regulating valve, the main pipeline is provided with a second electromagnetic regulating valve, and the heat source ports of the secondary air heat exchanger are provided with multiple groups, one group of heat source ports is connected to the main pipeline, and the other groups of heat source ports are connected to other supplied heat exchange sources. The steam bypass pipeline is added, so that when the three-extraction steam does not need to be regulated, the three-extraction steam can be circulated without passing through the hot secondary air heat exchanger, reducing unnecessary load, and can also be switched when the hot secondary air heat exchanger fails, improving the safety and stability of the system and reducing the standard coal consumption of power generation.

[0021] The air blower, air preheater and hot secondary air heat exchanger are provided in multiple groups, and the output ends of the multiple groups of hot secondary air heat exchangers are connected to the hot secondary air box. The connection structure of each group of air blower, air preheater and hot secondary air heat exchanger is the same as that of the first group.

[0022] The data acquisition module includes a temperature sensor, an air volume sensor, a three-extraction steam flow sensor and a storage module. The temperature sensor and the three-extraction steam flow sensor are used to collect the current temperature and flow of the three-extraction steam, and the air volume sensor is used to collect the air volume of the blower.

[0023] The heat exchange source supplied by the hot secondary air heat exchanger is provided with a flow acquisition interface, and the data output end of the flow acquisition interface is connected to a storage module, and the storage module is also used to connect a temperature sensor, an air volume sensor, and a three-extraction steam flow sensor to store real-time collected data and add a time stamp, and the storage module is connected to a human-computer interaction terminal to provide a data retrieval function, which is convenient for data retrieval.

[0024] The temperature difference calculation module includes a threshold setting module, a mode switching module and a calculation control module. The threshold setting module is used to connect to the human-computer interaction terminal, and provides the operator with the function of setting the temperature threshold for the three-extraction steam control. The mode switching module has a built-in comparison algorithm, and the mode switching module is connected to the storage module, and the real-time collected three-extraction steam temperature is compared with the set temperature threshold to determine whether the three-extraction steam temperature needs to be regulated. When it is determined that it is necessary, the main pipeline is opened and the steam bypass pipeline is closed. When it is determined that it is not necessary, the steam bypass pipeline is opened and the main pipeline is closed. The present invention can collect data through the control system, and cut the main pipeline and the steam bypass pipeline according to whether the three-extraction steam temperature needs to be regulated. When the three-extraction steam does not need to be regulated, the three-extraction steam is circulated without passing through the hot secondary air heat exchanger, reducing unnecessary loads. It can also be switched when the hot secondary air heat exchanger fails, improving the safety and stability of the system and reducing the standard coal consumption for power generation.

[0025] The calculation and control module is used to trigger the start when it is determined that the temperature of the three-extraction steam needs to be regulated. The calculation and control module first identifies the current operating parameters of the overall turbine system, determines the real-time adjustable parameters and non-adjustable parameters of the system, and when the real-time heat exchange source quantity supplied by the hot secondary air heat exchanger of the system is not adjustable, the air supply volume of the blower is adjusted, and the heat exchange difference of the air supply volume is used to adjust the temperature of the three-extraction steam.

[0026] Define the key variables: T3 extraction: Temperature of the third extraction steam (target variable).

[0027] Q Air supply: The amount of heat exchange provided by the air supply fan, which depends on the air supply volume and other factors (such as air supply temperature, humidity, etc.).

[0028] V air supply: air supply volume of the blower (controlled variable).

[0029] Tsupply air: supply air temperature (a constant or measurable variable).

[0030] Cp: ​​specific heat capacity of air (constant).

[0031] ΔT heat exchange: The heat exchange temperature difference caused by the change of air supply volume (related to V supply and T supply).

[0032] Assume that the relationship between the heat exchange Qsupply, air volume Vsupply and air temperature Tsupply is: Q air supply = Cp⋅V air supply⋅ΔT heat exchange Assume that the relationship function between the temperature of the three-extraction steam T3 extraction and the heat exchange Q supply air is: T3 extraction = f (Q air supply, other parameters) Since the "other parameters" are considered non-adjustable, they are treated as known quantities and simplified to: T3 extraction ≈ g(Q air supply) Substitute the expression of Q air supply into the above formula to obtain: T3 extraction ≈ g(Cp ⋅ V air supply ⋅ ΔT heat exchange) ΔT heat exchange itself is related to V air supply and other factors. An iterative or feedback control strategy is adopted to adjust V air supply in real time to achieve the required T3 extraction.

[0033] When the required air volume of the hot secondary air box in the system is fixed in real time, it is determined that the air supply volume of the current air blower cannot be adjusted. Then, adjust the heat exchange source volume supplied by other parts of the hot secondary air heat exchanger, and use the heat supply difference of the heat exchange source supplied by other parts to adjust the temperature of the three - extraction steam.

[0034] Define variables: Q other: The heat exchange amount provided by the heat exchange source volume supplied by other parts of the hot secondary air heat exchanger.

[0035] ΔQ other: The change in heat exchange amount due to adjusting the heat exchange source volume supplied by other parts.

[0036] Assume that there is a relationship between the temperature of the three - extraction steam and the total heat exchange amount provided by all heat exchange sources. This total heat exchange amount is regarded as the sum of the heat exchange amount provided by the air blower (Q air supply) and the heat exchange amount provided by the heat exchange source volume supplied by other parts (Q other). Since the air supply volume is fixed, by adjusting Q other to affect the total heat exchange amount, the following relational expression is written: T3 extraction ≈ h(Q total) where Q total = Q air supply + Q other. But since Q air supply is fixed, it is further simplified to: T3 extraction ≈ h(Q air supply + Q other) Change T3 extraction by adjusting ΔQ other. Since Q air supply is a constant, rewrite the above formula as: T3 extraction ≈ h(C + Q other) where C = Q air supply (constant).

[0037] To represent the relationship between T3 extraction and ΔQ other, assume there is an approximate linear or non - linear relationship: T3 extraction ≈ k ⋅ (Q air supply + Q other + ΔQ other) + b Further simplified to: T3 extraction ≈ k′ ⋅ (Q other + ΔQ other) + b′ where k′ and b′ are coefficients and intercepts calibrated from experimental data, reflecting the response characteristics of the system to changes in heat exchange amount.

[0038] The compensation module has a built-in compensation algorithm, and the compensation module is connected to the external steam cooler, which is used to collect the temperature of the three-extraction steam entering the external steam cooler after each regulation by the temperature difference calculation module, compare the temperature with the target temperature value regulated by the temperature difference calculation module, calculate the difference through the compensation algorithm, and apply the difference to the actual calculation of the calculation control module for regulation and compensation. The present invention can collect data through the control system, cut the main pipeline and the steam bypass pipeline according to whether the temperature of the three-extraction steam needs to be regulated, and when it is determined that regulation is needed, collect the real-time adjustable parameters and non-adjustable parameters of the system, thereby adjusting the air supply of the blower or the heat exchange source of other supplies of the hot secondary air heat exchanger according to the needs, so as to achieve the purpose of accurately controlling the temperature of the three-extraction steam, and compensate the possible errors in the calculation after multiple adjustments through the compensation module, so as to further improve the accuracy of controlling the temperature of the three-extraction steam.

[0039] Embodiment 2 according to Figure 1 , 2 As shown, this embodiment proposes a method for increasing the secondary air temperature, comprising the following steps: Connect the blower, air preheater, hot secondary air heat exchanger and hot secondary air box for air supply; The three-extraction steam is led to the hot secondary air heat exchanger through the main pipeline to heat the delivered air; Through the real-time overall dispatching system parameters of the control system, the temperature of the steam after heat exchange of the third extraction is controlled to reach the specified threshold; After the three-stage steam is heat exchanged, it enters the external steam cooler for cooling, and then enters the #3 high-pressure heater to heat the feed water; the steam parameters of the three-stage steam entering the external steam cooler and the #3 high-pressure heater are reduced, thereby reducing the temperature difference between the steam and water sides of the #3 high-pressure heater, ensuring the heat exchange environment of the high-pressure heater, and using this part of the temperature to further increase the hot secondary air temperature and reduce coal consumption; A steam bypass pipeline is added between the three-extraction steam and the external steam cooler, which is adjusted and switched according to the actual high and low loads and the failure of the hot secondary air heat exchanger. When the three-extraction steam does not need to be regulated, the three-extraction steam can be circulated without passing through the hot secondary air heat exchanger to reduce unnecessary load. It can also be switched when the hot secondary air heat exchanger fails, improving the safety and stability of the system and reducing the standard coal consumption of power generation.

[0040] The system and method for increasing the temperature of secondary air lead the tertiary extraction steam to the hot secondary air heat exchanger to heat the hot secondary air, and then return the steam to the external steam cooler and the #3 high-pressure heater to heat the water supply. The steam parameters of the tertiary extraction steam entering the external steam cooler and the #3 high-pressure heater are reduced, thereby reducing the temperature difference between the steam and water sides of the #3 high-pressure heater, ensuring the heat exchange environment of the high-pressure heater, and using this part of the temperature to further increase the hot secondary air temperature, reduce coal consumption, and improve boiler combustion efficiency. At the same time, the present invention adds a steam bypass pipeline, which can allow the tertiary extraction steam to circulate without passing through the hot secondary air heat exchanger when the tertiary extraction steam does not need to be regulated, thereby reducing unnecessary load, and can also switch when the hot secondary air heat exchanger fails, thereby improving the safety and stability of the system and reducing the standard coal consumption for power generation. In addition, the present invention can collect data through the control system, and cut the main pipeline and the steam bypass pipeline according to whether the temperature of the three-extraction steam needs to be regulated. When it is determined that regulation is needed, the real-time adjustable parameters and non-adjustable parameters of the system are collected, thereby adjusting the air supply volume of the blower or the heat exchange source volume of other supplies of the hot secondary air heat exchanger as needed, so as to achieve the purpose of accurately controlling the temperature of the three-extraction steam, and compensate for possible errors in the calculation after multiple adjustments through the compensation module, thereby further improving the accuracy of controlling the temperature of the three-extraction steam.

[0041] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A system for increasing the temperature of secondary air, comprising a component structure and a control system, characterized in that: The component structure includes an air blower, an air preheater, a hot secondary air heat exchanger and a hot secondary air box, the output end of the air blower is connected to the air preheater, and the output end of the air preheater is connected to the hot secondary air heat exchanger, the output end of the hot secondary air heat exchanger is connected to the hot secondary air box, the heat source port of the secondary air heat exchanger is connected to the three-extraction steam through the main pipeline, and the heat source port of the secondary air heat exchanger is connected to the external steam cooler, and a steam bypass pipeline is added between the three-extraction steam and the external steam cooler; The control system includes a data acquisition module, a temperature difference calculation module and a compensation module. The acquisition module is used to collect the real-time temperature of the current three-extraction steam. The temperature difference calculation module is used to calculate the load value for controlling the temperature of the three-extraction steam according to the preset three-extraction steam specified temperature. Therefore, the connection of the main pipeline or the steam bypass pipeline is first switched, and then the heat exchange source amount supplied by other sources of the hot secondary air heat exchanger or the air supply amount of the blower is adjusted to control the temperature of the three-extraction steam to the specified temperature. The compensation module is used to compensate for the error after the temperature difference calculation module is adjusted multiple times.

2. A system for increasing the temperature of secondary air according to claim 1, characterized in that: The steam bypass pipeline is provided with a first electromagnetic regulating valve, the main pipeline is provided with a second electromagnetic regulating valve, and the heat source ports of the secondary air heat exchanger are provided with multiple groups, one group of heat source ports is connected to the main pipeline, and the other groups of heat source ports are connected to other supplied heat exchange sources.

3. A system for increasing the temperature of secondary air according to claim 2, characterized in that: The air blower, air preheater and hot secondary air heat exchanger are all provided in multiple groups, and the output ends of the multiple groups of hot secondary air heat exchangers are all connected to the hot secondary air box.

4. A system for increasing the temperature of secondary air according to claim 2, characterized in that: The data acquisition module includes a temperature sensor, an air volume sensor, a three-extraction steam flow sensor and a storage module. The temperature sensor and the three-extraction steam flow sensor are used to collect the current temperature and flow of the three-extraction steam, and the air volume sensor is used to collect the air volume of the blower.

5. A system for increasing the temperature of secondary air according to claim 4, characterized in that: The other heat exchange sources supplied by the hot secondary air heat exchanger are derived from a flow collection interface, and the data output end of the flow collection interface is connected to a storage module. The storage module is also used to connect a temperature sensor, an air volume sensor, and a three-extraction steam flow sensor to store real-time collected data and timestamp it. The storage module is connected to a human-computer interaction terminal to provide a data retrieval function.

6. A system for increasing the temperature of secondary air according to claim 5, characterized in that: The temperature difference calculation module includes a threshold setting module, a mode switching module and a calculation control module. The threshold setting module is used to connect to the human-computer interaction terminal and provide the operator with a function of setting a temperature threshold for three-extraction steam control. The mode switching module has a built-in comparison algorithm, and the mode switching module is connected to the storage module. The real-time collected three-extraction steam temperature is compared with the set temperature threshold to determine whether the three-extraction steam temperature needs to be regulated. When it is determined to be necessary, the main pipeline is opened and the steam bypass pipeline is closed. When it is determined not to be necessary, the steam bypass pipeline is opened and the main pipeline is closed.

7. A system for increasing the temperature of secondary air according to claim 6, characterized in that: The calculation and control module is used to trigger the start when it is determined that the temperature of the three-extraction steam needs to be regulated. The calculation and control module first identifies the current operating parameters of the overall turbine system, determines the real-time adjustable parameters and non-adjustable parameters of the system, and when the real-time heat exchange source quantity supplied by the hot secondary air heat exchanger of the system is not adjustable, the air supply volume of the blower is adjusted, and the heat exchange difference of the air supply volume is used to adjust the temperature of the three-extraction steam.

8. A system for increasing the temperature of secondary air according to claim 7, characterized in that: When the real-time required air volume of the hot secondary air box of the system is fixed, it is determined that the air volume of the current blower cannot be adjusted, so the amount of other heat sources supplied by the hot secondary air heat exchanger is adjusted, and the heat supply difference of other heat sources is used to adjust the temperature of the three-extraction steam.

9. A system for increasing the temperature of secondary air according to claim 8, characterized in that: The compensation module has a built-in compensation algorithm, and the compensation module is connected to the external steam cooler, so as to collect the temperature of the three-extraction steam entering the external steam cooler after each regulation by the temperature difference calculation module, compare the temperature with the target temperature value regulated by the temperature difference calculation module, calculate the difference through the compensation algorithm, and apply the difference to the actual calculation of the calculation control module to perform regulation compensation.

10. A method for increasing the temperature of secondary air, using a system for increasing the temperature of secondary air as described in any one of 1 to 9 above, characterized in that: The following steps are involved: Connect the blower, air preheater, hot secondary air heat exchanger and hot secondary air box for air supply; The three-extraction steam is led to the hot secondary air heat exchanger through the main pipeline to heat the delivered air; Through the real-time overall dispatching system parameters of the control system, the temperature of the steam after heat exchange of the third extraction is controlled to reach the specified threshold; After the three-extraction steam has undergone heat exchange, it enters the external steam cooler for cooling, and then enters the #3 high-pressure heater for heating water supply; A steam bypass pipeline is added between the triple-extraction steam and the external steam cooler to adjust and switch according to the actual high and low loads and failures of the hot secondary air heat exchanger.

Images