Cogeneration industrial steam supply system and control method

Abstract

This application discloses a combined heat and power (CHP) industrial steam supply system and control method. The CHP industrial steam supply system includes: a steam supply end, a boiler, and a steam turbine generator. The steam outlet of the boiler is connected to the steam supply end through a first pipe. A first valve is installed on the first pipe, which is used to open when the steam supply pressure at the steam supply end is lower than a preset pressure value. The steam outlet of the boiler supplies steam to the outside through the steam supply end. The steam turbine generator includes a steam inlet, a front-stage extraction port, and a rear-stage extraction port. The steam outlet is connected to the steam inlet. The front-stage extraction port is connected to the steam supply end through a second pipe. A second valve is installed on the second pipe, which is used to open when the electrical load of the steam turbine generator is lower than a preset electrical load value. The front-stage extraction port supplies steam to the outside through the steam supply end. The rear-stage extraction port is connected to the steam supply end through a third pipe, which is installed on the third pipe. The third valve is used to open when the electrical load of the steam turbine generator is higher than a preset electrical load value. The rear-stage extraction port supplies steam to the outside.

Description

Technical Field

[0001] This application relates to the technical field, and in particular to a combined heat and power (CHP) industrial steam supply system and control method. Background Technology

[0002] A combined heat and power (CHP) power plant is a type of power plant that can simultaneously produce electricity and heat (supplying steam to external users). In a CHP plant, primary energy sources (such as coal, natural gas, biomass, etc.) are used to generate steam, which drives a turbine generator to produce electricity and also supplies steam to the public. The main advantages of CHP power plants include high energy efficiency, reduced greenhouse gas emissions, energy savings, and significant economic benefits.

[0003] However, when generator sets follow the grid requirements to change rated load and perform deep peak shaving, it is difficult to guarantee the stability of external steam supply. Summary of the Invention

[0004] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a combined heat and power (CHP) industrial steam supply system and control method, which can solve the problem that traditional CHP power plant technology struggles to guarantee the stability of external steam supply.

[0005] The cogeneration industrial steam supply system according to the first aspect of this application includes:

[0006] Steam supply end;

[0007] The boiler has its steam outlet connected to the steam supply end via a first pipe. A first valve is installed on the first pipe. The first valve is used to open when the steam supply pressure at the steam supply end is lower than a preset pressure value, so that the steam outlet of the boiler supplies steam to the outside through the steam supply end.

[0008] A steam turbine generator includes a steam inlet, a front-stage extraction port, and a rear-stage extraction port. A steam outlet is connected to the steam inlet. The front-stage extraction port is connected to the steam supply end via a second pipe. A second valve is installed on the second pipe. This second valve is used to open when the electrical load of the steam turbine generator is lower than a preset electrical load value, allowing the front-stage extraction port to supply steam to the outside through the steam supply end. The rear-stage extraction port is connected to the steam supply end via a third pipe. A third valve is installed on the third pipe. This third valve is used to open when the electrical load of the steam turbine generator is higher than the preset electrical load value, allowing the rear-stage extraction port to supply steam to the outside through the steam supply end.

[0009] The cogeneration industrial steam supply system according to the first aspect of this application has at least the following beneficial effects:

[0010] Steam in the turbine generator is consumed as it performs work as it travels from the front extraction port to the rear extraction port. When the electrical load of the turbine generator is lower than the preset electrical load value, indicating a smaller power generation, the amount of steam in the turbine generator is relatively small. The second valve is then opened, supplying steam to the outside through the front extraction port. Since less work is done at the front extraction port, the steam supply is larger than at the rear extraction port, ensuring sufficient steam supply. When the electrical load of the turbine generator is higher than the preset electrical load value, indicating a larger power generation, the amount of steam in the turbine generator is sufficient. The third valve is then opened, supplying steam to the outside through the rear extraction port, ensuring sufficient steam supply while allowing more work to be done by the steam, thus guaranteeing power generation. When the steam supply pressure at the supply end is lower than the preset pressure value, the first valve is opened, allowing the boiler's steam outlet to supply steam to the outside through the supply end, further increasing the steam supply. The cogeneration industrial steam supply system of the first aspect of this application, compared to traditional cogeneration power plant technology, can provide stable steam supply while meeting the power grid supply requirements.

[0011] According to some embodiments of this application, a steam header is also included, wherein the steam outlet, the pre-stage extraction port, and the post-stage extraction port are all connected to the inlet of the steam header, and the outlet of the steam header is connected to the steam supply end.

[0012] According to some embodiments of this application, a condenser is also included, and the steam turbine generator further includes an exhaust port connected to the inlet of the condenser, and the outlet of the condenser is connected to the feedwater inlet of the boiler.

[0013] According to some embodiments of this application, it further includes a return water end and a heat exchanger. The return water end is connected to the heat medium inlet of the heat exchanger through a fourth pipe. A fourth valve is provided on the fourth pipe. The heat medium outlet of the heat exchanger is connected to the feed water inlet of the condenser. The outlet of the condenser is connected to the refrigerant inlet of the heat exchanger. The refrigerant outlet of the heat exchanger is connected to the feed water inlet of the boiler.

[0014] According to some embodiments of this application, the device further includes a fan, an air preheater, a cooler, and a coal mill. The air outlet of the fan is connected to the inlet of the air preheater, the outlet of the air preheater is connected to the air inlet of the cooler, the air outlet of the cooler is connected to the air inlet of the coal mill, the return water end is connected to the water inlet of the cooler through a fifth pipe, a fifth valve is provided on the fifth pipe, and the water outlet of the cooler is connected to the heat medium inlet of the heat exchanger.

[0015] According to some embodiments of this application, a water purification device is also included, which includes a permanent magnet iron removal filter, a countercurrent regeneration cation exchanger, a first resin trap, a mixed ion exchanger, and a second resin trap connected in sequence. The heat medium outlet of the heat exchanger is connected to the permanent magnet iron removal filter, and the second resin trap is connected to the water inlet of the condenser.

[0016] According to some embodiments of this application, the water purification device further includes a first water tank and a second water tank. The inlet of the first water tank is connected to the heat medium outlet of the heat exchanger, the outlet of the first water tank is connected to the permanent magnet iron removal filter, the inlet of the second water tank is connected to the second resin trap, and the outlet of the second water tank is connected to the water supply outlet of the condenser.

[0017] The steam supply system control method according to the second aspect of this application includes:

[0018] The electrical load of the steam turbine generator is obtained. If the electrical load is lower than the preset electrical load value, the second valve is controlled to open so that the front-stage extraction port supplies steam to the outside through the steam supply end. Otherwise, the third valve is controlled to open so that the rear-stage extraction port supplies steam to the outside through the steam supply end.

[0019] The steam supply pressure at the steam supply end is obtained. If the steam supply pressure is lower than the preset pressure value, the first valve is controlled to open, so that the steam outlet of the boiler supplies steam to the outside through the steam supply end.

[0020] The steam supply system control method according to the second aspect of this application has at least the following beneficial effects:

[0021] Steam in the turbine generator is consumed as it performs work as it travels from the front extraction port to the rear extraction port. When the electrical load of the turbine generator is lower than the preset electrical load value, indicating a smaller power generation, the amount of steam in the turbine generator is relatively small. The second valve is then opened, supplying steam to the outside through the front extraction port. Since less work is done at the front extraction port, the steam supply is larger than at the rear extraction port, ensuring sufficient steam supply. When the electrical load of the turbine generator is higher than the preset electrical load value, indicating a larger power generation, the amount of steam in the turbine generator is sufficient. The third valve is then opened, supplying steam to the outside through the rear extraction port, ensuring sufficient steam supply while allowing more work to be done by the steam, thus guaranteeing power generation. When the steam supply pressure at the supply end is lower than the preset pressure value, the first valve is opened, allowing the boiler's steam outlet to supply steam to the outside through the supply end, further increasing the steam supply. The cogeneration industrial steam supply system of the first aspect of this application, compared to traditional cogeneration power plant technology, can provide stable steam supply while meeting the power grid supply requirements.

[0022] According to some embodiments of this application, it further includes: controlling the fourth valve to open, so that the return water at the return water end exchanges heat with the condensate of the condenser and flows into the water inlet of the condenser to replenish the condenser.

[0023] According to some embodiments of this application, it further includes: controlling the fifth valve to open, so that the return water at the return water end exchanges heat with the hot primary air discharged from the air preheater, and then exchanges heat with the condensate of the condenser before flowing into the water inlet of the condenser to replenish the condenser.

[0024] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0025] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0026] Figure 1 This is a schematic diagram of the structure of a cogeneration industrial steam supply system in one embodiment of this application;

[0027] Figure 2 This is a schematic diagram of the structure of a water purification device in one embodiment of this application;

[0028] Figure 3 This is a flowchart of a steam supply system control method in one embodiment of this application.

[0029] Figure label:

[0030] Steam supply end 100

[0031] Boiler 200

[0032] Steam turbine generator 300, first valve 310, second valve 320, third valve 330

[0033] Fourth valve 340, fifth valve 350, condenser 360,

[0034] Steam header 400

[0035] 500 return water end

[0036] Heat exchanger 600

[0037] Fan 700, air preheater 710, cooler 720, coal mill 730

[0038] Water purification device 800, permanent magnet iron removal filter 810,

[0039] Countercurrent regeneration cation exchanger 820, first resin trap 830,

[0040] Hybrid ion exchanger 840, second resin trap 850,

[0041] First water pump 860, second water pump 870, first water tank 880

[0042] Second water tank 890. Detailed Implementation

[0043] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0044] In the description of this application, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0045] In the description of this application, "multiple" refers to two or more. The use of "first" and "second" is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or the order in which the technical features are indicated.

[0046] In the description of this application, unless otherwise expressly defined, terms such as "setting," "installation," and "electrical connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0047] The following is for reference. Figures 1 to 3 This application describes a combined heat and power (CHP) industrial steam supply system and a steam supply system control method according to embodiments thereof.

[0048] The cogeneration industrial steam supply system of this application embodiment, such as Figure 1As shown, it includes: a steam supply end 100, a boiler 200 and a steam turbine generator 300. The steam outlet of the boiler 200 is connected to the steam supply end 100 through a first pipe. A first valve 310 is provided on the first pipe. The first valve 310 is used to open when the steam supply pressure of the steam supply end 100 is lower than a preset pressure value, so that the steam outlet of the boiler 200 supplies steam to the outside through the steam supply end 100. The steam turbine generator 300 includes a steam inlet, a front-stage extraction port, and a rear-stage extraction port. The steam outlet is connected to the steam inlet. The front-stage extraction port is connected to the steam supply end 100 through a second pipe. A second valve 320 is installed on the second pipe. The second valve 320 is used to open when the electrical load of the steam turbine generator 300 is lower than a preset electrical load value, so that the front-stage extraction port supplies steam to the outside through the steam supply end 100. The rear-stage extraction port is connected to the steam supply end 100 through a third pipe. A third valve 330 is installed on the third pipe. The third valve 330 is used to open when the electrical load of the steam turbine generator 300 is higher than a preset electrical load value, so that the rear-stage extraction port supplies steam to the outside through the steam supply end 100.

[0049] In this embodiment, the steam in the turbine generator 300 is consumed as it performs work from the front extraction port to the rear extraction port. When the electrical load of the turbine generator 300 is lower than the preset electrical load value, it indicates that the power generation is small and the amount of steam in the turbine generator 300 is relatively small. The second valve 320 is opened to supply steam to the outside through the front extraction port. The steam at the front extraction port performs less work, and the steam supply is larger than that at the rear extraction port, ensuring the steam supply. When the electrical load of the turbine generator 300 is higher than the preset electrical load value, it indicates that the power generation is large and the amount of steam in the turbine generator 300 is sufficient. The third valve 330 is opened to supply steam to the outside through the rear extraction port, ensuring the steam supply while allowing the steam to perform more work, ensuring the power generation and reducing the coal consumption for power generation. When the steam supply pressure at the steam supply end 100 is lower than the preset pressure value, the first valve 310 is opened to allow the steam outlet of the boiler 200 to supply steam to the outside through the steam supply end 100, further increasing the steam supply. The cogeneration industrial steam supply system of the first aspect of this application, compared with traditional cogeneration power plant technology, can stably supply steam while meeting the power grid supply requirements.

[0050] It is understandable that the front-stage extraction port is the extraction port located at the position corresponding to the front-stage blade of the steam turbine generator 300, and the rear-stage extraction port is the extraction port located at the position corresponding to the rear-stage blade of the steam turbine generator 300.

[0051] It is understandable that both the first valve 310 and the second valve 320 are desuperheating and pressure reducing valves, which can cool and reduce the pressure of high-temperature and high-pressure steam.

[0052] It should be noted that steam supply end 100 is the steam supply main pipe.

[0053] One embodiment of this application, such as Figure 1As shown, it also includes a steam header 400, with the steam outlet, the front-stage extraction port and the rear-stage extraction port all connected to the inlet of the steam header 400, and the outlet of the steam header 400 connected to the steam supply end 100.

[0054] In this embodiment, the steam discharged from the steam outlet, the front-stage extraction port, and the rear-stage extraction port all enter the steam header 400 for storage, and then supply steam to the steam supply end 100 through the steam header 400. As a steam storage device, the steam header 400 greatly improves the safety and stability of the external steam supply system, eliminates the impact of large fluctuations in the electrical and thermal load of the cogeneration industrial steam supply system on steam users, and avoids the impact of large fluctuations in steam consumption by steam users on the cogeneration industrial steam supply system.

[0055] It should be noted that the steam header 400 is also equipped with a safety valve, a drain device, an external steam distribution device, and an isolation device.

[0056] One embodiment of this application, such as Figure 1 As shown, it also includes a condenser 360, and the steam turbine generator 300 also includes an exhaust port, which is connected to the inlet of the condenser 360, and the outlet of the condenser 360 is connected to the feedwater inlet of the boiler 200.

[0057] In this embodiment, after the steam in the steam turbine generator 300 has completed its work, it is condensed into condensate through the condenser 360 and then fed into the water inlet of the boiler 200 to replenish the boiler 200 with water.

[0058] One embodiment of this application, such as Figure 1 As shown, it also includes a return water end 500 and a heat exchanger 600. The return water end 500 is connected to the heat medium inlet of the heat exchanger 600 through a fourth pipe. A fourth valve 340 is installed on the fourth pipe. The heat medium outlet of the heat exchanger 600 is connected to the feed water inlet of the condenser 360. The outlet of the condenser 360 is connected to the refrigerant inlet of the heat exchanger 600. The refrigerant outlet of the heat exchanger 600 is connected to the feed water inlet of the boiler 200.

[0059] In this embodiment, the return water generated after steam is supplied to the outside at the steam supply end 100 enters the heat exchanger 600 through the return water end 500 and the fourth pipe. The condensate formed in the condenser 360 exchanges heat with the return water in the heat exchanger 600. The condensate recovers the waste heat of the return water and inputs it into the boiler 200 to improve the energy utilization rate. After heat exchange, the return water enters the condenser 360 to replenish the condenser 360.

[0060] Understandably, the return end 500 is the return jellyfish pipe.

[0061] One embodiment of this application, such as Figure 1As shown, it also includes a fan 700, an air preheater 710, a cooler 720, and a coal mill 730. The air outlet of the fan 700 is connected to the inlet of the air preheater 710, the outlet of the air preheater 710 is connected to the air inlet of the cooler 720, the air outlet of the cooler 720 is connected to the air inlet of the coal mill 730, the return water end 500 is connected to the water inlet of the cooler 720 through a fifth pipe, a fifth valve 350 is installed on the fifth pipe, and the water outlet of the cooler 720 is connected to the heat medium inlet of the heat exchanger 600.

[0062] In this embodiment, cold primary air enters the air preheater 710 via the fan 700. Since the temperature of the hot primary air at the outlet of the air preheater 710 is higher than the required temperature of the drying medium at the inlet of the coal mill 730, the return water from the return water end 500 is opened via the fifth valve 350 and exchanges heat with the hot primary air through the cooler 720 to cool the hot primary air and recover its heat for subsequent heat exchange with the condensate, thus improving energy utilization. Traditional high-speed mill direct-fired pulverizing systems adjust the exhaust air temperature of the coal mill 730 by mixing cold and hot primary air. This operation, by bypassing some of the cold primary air, reduces the total amount of cold air passing through the air preheater 710, which can increase the exhaust temperature of the boiler 200. In this embodiment, more cold primary air passes through the air preheater 710 to facilitate heat exchange between the cold primary air and the flue gas at the front of the boiler 200's tail flue, recovering heat from the boiler 200's flue gas and reducing the boiler 200's exhaust temperature.

[0063] Understandably, the selected range for the hot primary air temperature at the outlet of the air preheater 710 has a certain margin, mostly between 320℃ and 330℃, to maintain sufficient drying capacity for the pulverizing system, while the inlet air temperature of the coal mill 730 is mostly between 150℃ and 260℃. Therefore, when the hot primary air temperature at the outlet of the air preheater 710 is detected to be higher than 280℃, the fifth valve 350 is opened, allowing the return water at the return water end 500 to exchange heat with the hot primary air through the cooler 720, thus cooling the hot primary air. Furthermore, by controlling the opening of the fourth valve 340, the flow rate of the return water can be assisted in regulating without affecting the recovery of the return water.

[0064] One embodiment of this application, such as Figures 1 to 2 As shown, it also includes a water purification device 800, which includes a permanent magnet iron removal filter 810, a countercurrent regeneration cation exchanger 820, a first resin trap 830, a mixed ion exchanger 840 and a second resin trap 850 connected in sequence. The heat medium outlet of the heat exchanger 600 is connected to the permanent magnet iron removal filter 810, and the second resin trap 850 is connected to the water inlet of the condenser 360.

[0065] In this embodiment, the return water is sequentially processed through a permanent magnet iron removal filter 810, a countercurrent regeneration cation exchanger 820, a first resin trap 830, a mixed ion exchanger 840, and a second resin trap 850 before being fed into the condenser 360 as makeup water. This reduces the makeup water rate of the cogeneration industrial steam supply system, lowers the dissolved oxygen rate of the feedwater, improves the quality of the feedwater, and reduces corrosion.

[0066] One embodiment of this application, such as Figure 2 As shown, the water purification device 800 also includes a first water tank 880 and a second water tank 890. The inlet of the first water tank 880 is connected to the heat medium outlet of the heat exchanger 600, and the outlet of the first water tank 880 is connected to the permanent magnet iron removal filter 810. The inlet of the second water tank 890 is connected to the second resin trap 850, and the outlet of the second water tank 890 is connected to the water supply outlet of the condenser 360.

[0067] In this embodiment, after the return water is discharged from the heat medium outlet of the heat exchanger 600, it enters the first water tank 880 for storage. After being treated by the permanent magnet iron removal filter 810, the countercurrent regeneration cation exchanger 820, the first resin trap 830, the mixed ion exchanger 840, and the second resin trap 850, the return water enters the second water tank 890 for storage. The first water tank 880 and the second water tank 890 can keep the return water stable and avoid excessive changes in the return water flow rate.

[0068] It should be noted that, as Figure 2 As shown, the water purification device 800 also includes a first water pump 860 and a second water pump 870. The first water pump 860 is installed between the first water tank 880 and the permanent magnet iron removal filter 810, and is used to provide power to transport water in the first water tank 880 to the iron removal filter. The second water pump 870 is installed between the second water tank 890 and the condenser 360, and is used to provide power to transport water in the second water tank 890 to the condenser 360.

[0069] The steam supply system control method of this application embodiment, such as Figure 3 As shown, this includes, but is not limited to, steps S100 and S200.

[0070] Step S100: Obtain the electrical load of the steam turbine generator 300. If the electrical load is lower than the preset electrical load value, control the second valve 320 to open so that the front-stage extraction port can supply steam to the outside through the steam supply end 100. Otherwise, control the third valve 330 to open so that the rear-stage extraction port can supply steam to the outside through the steam supply end 100.

[0071] Step S200: Obtain the steam supply pressure of the steam supply end 100. If the steam supply pressure is lower than the preset pressure value, control the first valve 310 to open, so that the steam outlet of the boiler 200 supplies steam to the outside through the steam supply end 100.

[0072] In this embodiment, the steam in the turbine generator 300 is consumed as it performs work from the front extraction port to the rear extraction port. When the electrical load of the turbine generator 300 is lower than the preset electrical load value, it indicates that the power generation is small and the amount of steam in the turbine generator 300 is relatively small. The second valve 320 is opened to supply steam to the outside through the front extraction port. The steam at the front extraction port performs less work, and the steam supply is larger than that at the rear extraction port, ensuring the steam supply. When the electrical load of the turbine generator 300 is higher than the preset electrical load value, it indicates that the power generation is large and the amount of steam in the turbine generator 300 is sufficient. The third valve 330 is opened to supply steam to the outside through the rear extraction port, ensuring the steam supply while allowing the steam to perform more work, thus ensuring the power generation. When the steam supply pressure at the steam supply end 100 is lower than the preset pressure value, the first valve 310 is opened to allow the steam outlet of the boiler 200 to supply steam to the outside through the steam supply end 100, further increasing the steam supply. The cogeneration industrial steam supply system of this application embodiment, compared with traditional cogeneration power plant technology, can stably supply steam while meeting the power grid supply requirements.

[0073] In one embodiment of this application, the steam supply system control method further includes, but is not limited to, step S300.

[0074] Step S300: Control the fourth valve 340 to open, so that the return water at the return water end 500 exchanges heat with the condensate of the condenser 360 and flows into the feed water port of the condenser 360 to replenish the condenser 360.

[0075] In this embodiment, by controlling the fourth valve 340 to open, the return water from the return water end 500 enters the heat exchanger 600 to exchange heat with the condensate, and then inputs it into the condenser 360 to replenish the condenser 360.

[0076] According to some embodiments of this application, the steam supply system control method also includes, but is not limited to, step S400.

[0077] Step S400: Control the fifth valve 350 to open, so that the return water at the return water end 500 exchanges heat with the hot primary air discharged from the air preheater 710, and then exchanges heat with the condensate of the condenser 360 before flowing into the water inlet of the condenser 360 to replenish the condenser 360.

[0078] In this embodiment, by controlling the fifth valve 350 to open, the return water from the return water end 500 exchanges heat with the hot primary air discharged from the air preheater 710 through the cooler 720. After absorbing the heat of the hot primary air, the return water flows into the heat exchanger 600 to exchange heat with the condensate.

[0079] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

Claims

1. A combined heat and power (CHP) industrial steam supply system, characterized in that, include: Steam supply end; The boiler has its steam outlet connected to the steam supply end via a first pipe. A first valve is installed on the first pipe. The first valve is used to open when the steam supply pressure at the steam supply end is lower than a preset pressure value, so that the steam outlet of the boiler supplies steam to the outside through the steam supply end. A steam turbine generator includes a steam inlet, a front-stage extraction port, and a rear-stage extraction port. A steam outlet is connected to the steam inlet. The front-stage extraction port is connected to the steam supply end via a second pipe. A second valve is installed on the second pipe. This second valve is used to open when the electrical load of the steam turbine generator is lower than a preset electrical load value, allowing the front-stage extraction port to supply steam to the outside through the steam supply end. The rear-stage extraction port is connected to the steam supply end via a third pipe. A third valve is installed on the third pipe. This third valve is used to open when the electrical load of the steam turbine generator is higher than the preset electrical load value, allowing the rear-stage extraction port to supply steam to the outside through the steam supply end. The cogeneration industrial steam supply system also includes a condenser, and the steam turbine generator also includes an exhaust port, which is connected to the inlet of the condenser, and the outlet of the condenser is connected to the feedwater inlet of the boiler. The combined heat and power industrial steam supply system further includes a return water end and a heat exchanger. The return water end is connected to the heat medium inlet of the heat exchanger through a fourth pipe. A fourth valve is installed on the fourth pipe. The heat medium outlet of the heat exchanger is connected to the feed water inlet of the condenser. The outlet of the condenser is connected to the refrigerant inlet of the heat exchanger. The refrigerant outlet of the heat exchanger is connected to the feed water inlet of the boiler. The combined heat and power (CHP) industrial steam supply system also includes a fan, an air preheater, a cooler, and a coal mill. The air outlet of the fan is connected to the inlet of the air preheater, the outlet of the air preheater is connected to the air inlet of the cooler, the air outlet of the cooler is connected to the air inlet of the coal mill, the return water end is connected to the water inlet of the cooler through a fifth pipe, a fifth valve is installed on the fifth pipe, and the water outlet of the cooler is connected to the heat medium inlet of the heat exchanger.

2. The cogeneration industrial steam supply system according to claim 1, characterized in that: It also includes a steam header, wherein the steam outlet, the front-stage extraction port and the rear-stage extraction port are all connected to the inlet of the steam header, and the outlet of the steam header is connected to the steam supply end.

3. The cogeneration industrial steam supply system according to claim 1, characterized in that: It also includes a water purification device, which comprises a permanent magnet iron removal filter, a countercurrent regeneration cation exchanger, a first resin trap, a mixed ion exchanger, and a second resin trap connected in sequence. The heat medium outlet of the heat exchanger is connected to the permanent magnet iron removal filter, and the second resin trap is connected to the water inlet of the condenser.

4. The cogeneration industrial steam supply system according to claim 3, characterized in that: The water purification device further includes a first water tank and a second water tank. The inlet of the first water tank is connected to the heat medium outlet of the heat exchanger, the outlet of the first water tank is connected to the permanent magnet iron removal filter, the inlet of the second water tank is connected to the second resin trap, and the outlet of the second water tank is connected to the water supply port of the condenser.

5. A steam supply system control method, applied to a cogeneration industrial steam supply system as described in any one of claims 1 to 4, characterized in that, include: The electrical load of the steam turbine generator is obtained. If the electrical load is lower than the preset electrical load value, the second valve is controlled to open so that the front-stage extraction port supplies steam to the outside through the steam supply end. Otherwise, the third valve is controlled to open so that the rear-stage extraction port supplies steam to the outside through the steam supply end. The steam supply pressure at the steam supply end is obtained. If the steam supply pressure is lower than the preset pressure value, the first valve is controlled to open, so that the steam outlet of the boiler supplies steam to the outside through the steam supply end.

6. The steam supply system control method according to claim 5, characterized in that, Also includes: The fourth valve is opened to allow the return water at the return water end to exchange heat with the condensate of the condenser and then flow into the feed water port of the condenser to replenish the condenser.

7. The steam supply system control method according to claim 5, characterized in that, Also includes: The fifth valve is opened to allow the return water at the return water end to exchange heat with the hot primary air discharged from the air preheater, and then exchange heat with the condensate of the condenser before flowing into the water inlet of the condenser to replenish the condenser.

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