Combined heat and power generation device and system for low-pressure cylinder micro-output combined high-back-pressure transformation

Abstract

The utility model provides a combined heat and power generation device and system for low-pressure cylinder micro-output combined high-back-pressure transformation, and belongs to the technical field of thermoelectric decoupling. The combined heat and power generation device comprises a first intermediate discharge steam extraction and supply unit for providing first intermediate discharge steam extraction, a low-pressure cylinder output adjusting unit for reducing first low-pressure cylinder output, and a second intermediate discharge steam extraction and supply unit for providing second intermediate discharge steam extraction; the first backpressure power generation unit generates power and supplies heat based on first intermediate discharge steam extraction, and the first heat supply network heating unit secondarily heats heat supply network return water based on the first intermediate discharge steam extraction; the second intermediate exhaust steam extraction and supply unit provides second intermediate exhaust steam extraction, the exhaust steam flow adjusting unit adjusts the exhaust steam flow so that the second cogeneration unit can be switched to operate under different working conditions, the high-back-pressure heating unit conducts primary heating on heat supply network return water, and the second back-pressure power generation unit generates power and supplies heat based on the second intermediate exhaust steam extraction. And the second heat supply network heating unit secondarily heats the heat supply network return water. According to the scheme, the heat efficiency, the waste heat utilization rate, the energy utilization rate and the peak regulation flexibility of the cogeneration unit can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of thermoelectric decoupling, and specifically to a cogeneration device and system for low-pressure cylinder micro-output combined with high back-pressure transformation. Background Art

[0002] At present, the cogeneration technology plays an indispensable role in ensuring people's livelihood heating. Promoting the flexibility transformation of existing coal-fired power units, especially cogeneration units, has become a top priority. Improving the flexibility of units through different thermoelectric decoupling technologies is a relatively effective technical approach.

[0003] In the prior art, thermoelectric decoupling technologies mainly include: configuring a hot water storage tank, configuring an electric boiler, removing the low-pressure cylinder, high back-pressure transformation, bypass heating, and waste heat heating, etc. However, these thermoelectric decoupling technologies each have certain disadvantages. Traditional cogeneration units use the extraction steam from the intermediate-pressure cylinder for heating during extraction steam heating. The cold source loss of the exhaust steam of the low-pressure cylinder cannot be fully utilized, and a large amount of extraction steam from the intermediate extraction is only used for heating, and high-grade heat is used after being degraded, resulting in low energy utilization efficiency. In addition, the peak shaving flexibility of traditional cogeneration units is poor.

[0004] Therefore, how to improve the thermal efficiency, waste heat utilization rate, energy utilization rate, and peak shaving flexibility of cogeneration units has become a problem to be solved. Summary of the Utility Model

[0005] The purpose of the present application is to provide a cogeneration device and system for low-pressure cylinder micro-output combined with high back-pressure transformation, which can solve the problems of low thermal efficiency, waste heat utilization rate, and energy utilization rate, and poor peak shaving flexibility of the cogeneration units in the prior art.

[0006] In the first aspect, an embodiment of the present application provides a cogeneration device for low-pressure cylinder micro-output combined with high back-pressure transformation, the device includes:

[0007] The first extraction steam supply unit of the first cogeneration unit, the low-pressure cylinder output adjustment unit, the first low-pressure cylinder, the first back-pressure power generation unit, the first heat network heating unit, and the first exhaust steam pipeline disposed between the fourth output end of the first extraction steam supply unit and the steam inlet of the first low-pressure cylinder, the second extraction steam supply unit of the second cogeneration unit, the exhaust steam flow adjustment unit, the second low-pressure cylinder, the high back-pressure heating unit, the second back-pressure power generation unit, the second heat network heating unit, and the second exhaust steam pipeline disposed between the third output end of the second extraction steam supply unit and the steam inlet of the second low-pressure cylinder;

[0008] The first output end of the first intermediate extraction steam supply unit is connected to the first input end of the first back-pressure power generation unit. The second output end of the first intermediate extraction steam supply unit is connected to the second input end of the first heat network heating unit. The third output end of the first intermediate extraction steam supply unit is connected to the third input end of the first heat network heating unit. The fourth output end of the first intermediate extraction steam supply unit is connected to the first end of the low-pressure cylinder output regulation unit. The first intermediate extraction steam supply unit is used to supply the first intermediate extraction steam to the first back-pressure power generation unit and the first heat network heating unit;

[0009] The low-pressure cylinder output regulation unit is arranged on the first exhaust steam pipeline. The second end of the low-pressure cylinder output regulation unit is connected to the steam inlet of the first low-pressure cylinder. The exhaust outlet of the first low-pressure cylinder is connected to the input end of the first air-cooled island. The low-pressure cylinder output regulation unit is used to reduce the output of the first low-pressure cylinder;

[0010] The second input end of the first back-pressure power generation unit is connected to the first output end of the high back-pressure heating unit. The output end of the first back-pressure power generation unit is respectively connected to the output end of the second back-pressure power generation unit and the first input end of the first heat network heating unit. The first back-pressure power generation unit is used to generate electricity and supply heat based on the first intermediate extraction steam;

[0011] The output end of the first heat network heating unit outputs heat network supply water. The first heat network heating unit is used to reheat the heat network return water that has been preliminarily heated by the high back-pressure heating unit based on the first intermediate extraction steam and output the heated heat network return water;

[0012] The first output end of the second intermediate extraction steam supply unit is connected to the first input end of the second back-pressure power generation unit. The second output end of the second intermediate extraction steam supply unit is connected to the second input end of the second heat network heating unit. The third output end of the second intermediate extraction steam supply unit is connected to the first end of the exhaust steam flow regulation unit. The second intermediate extraction steam supply unit is used to supply the second intermediate extraction steam to the second back-pressure power generation unit and the second heat network heating unit;

[0013] The exhaust steam flow regulation unit is arranged on the second exhaust steam pipeline. The second end of the exhaust steam flow regulation unit is connected to the steam inlet of the second low-pressure cylinder. The first exhaust outlet of the second low-pressure cylinder is connected to the input end of the second air-cooled island. The exhaust steam flow regulation unit is used to regulate the exhaust steam flow input to the second low-pressure cylinder so that the second cogeneration unit can switch between pure condensing, extraction condensing or back-pressure operating conditions;

[0014] The first input end of the high back-pressure heating unit is connected to the second exhaust outlet of the second low-pressure cylinder. The second input end of the high back-pressure heating unit inputs heat network return water. The second output end of the high back-pressure heating unit is connected to the input end of the exhaust steam device. The high back-pressure heating unit is used to preliminarily heat the heat network return water based on the exhaust steam of the second low-pressure cylinder;

[0015] The second input end of the second back-pressure power generation unit is connected to the first output end of the high back-pressure heating unit, and the output end of the second back-pressure power generation unit is connected to the first input end of the second heat network heating unit. The second back-pressure power generation unit is used for generating electricity and heating based on the second extraction steam from the middle stage.

[0016] The output end of the second heat network heating unit outputs heat network supply water. The second heat network heating unit is used for secondary heating of the heat network return water heated by the high back-pressure heating unit based on the second extraction steam from the middle stage, and outputs the heated heat network return water.

[0017] In a possible implementation manner of the first aspect, the first extraction steam supply unit from the middle stage includes: a first intermediate pressure cylinder and a first extraction steam control module from the middle stage;

[0018] The first end of the first extraction steam control module from the middle stage is respectively connected to the exhaust outlet of the first intermediate pressure cylinder and the first end of the low-pressure cylinder output regulating unit. The second end of the first extraction steam control module from the middle stage is connected to the input end of the first back-pressure power generation unit. The third end of the first extraction steam control module from the middle stage is connected to the second input end of the first heat network heating unit. The fourth end of the first extraction steam control module from the middle stage is connected to the third input end of the first heat network heating unit. The first extraction steam control module from the middle stage is used for controlling the first extraction steam from the middle stage.

[0019] In a possible implementation manner of the first aspect, the low-pressure cylinder output regulating unit includes a double-valve plate heating butterfly valve; the double-valve plate heating butterfly valve is arranged on the first exhaust pipeline. The first end of the double-valve plate heating butterfly valve is connected to the fourth output end of the first extraction steam supply unit from the middle stage, and the second end of the double-valve plate heating butterfly valve is connected to the steam inlet of the first low-pressure cylinder.

[0020] In a possible implementation manner of the first aspect, the first extraction steam control module from the middle stage includes: a first pneumatic check valve, a first hydraulic quick-closing regulating valve, a first electric shut-off valve, a first steam supply gate valve, a first steam supply regulating valve, a first main steam supply pipeline arranged between the exhaust outlet of the first intermediate pressure cylinder and the second input end of the first heat network heating unit, a first bypass steam supply pipeline arranged between the second end of the first electric shut-off valve and the input end of the first back-pressure power generation unit, and a second bypass steam supply pipeline arranged between the second end of the first electric shut-off valve and the third input end of the first heat network heating unit;

[0021] The first pneumatic check valve, the first hydraulic quick-closing regulating valve, and the first electric shut-off valve are sequentially arranged on the first main steam supply pipeline. The first steam supply gate valve is arranged on the first bypass steam supply pipeline. The first steam supply regulating valve is arranged on the second bypass steam supply pipeline;

[0022] The first end of the first pneumatic check valve is connected to the first end of the low-pressure cylinder output regulating unit. The second end of the first pneumatic check valve is connected to the first end of the first hydraulic quick-closing regulating valve. The second end of the first hydraulic quick-closing regulating valve is connected to the first end of the first electric shut-off valve. The second end of the first electric shut-off valve, the first end of the first steam supply stop valve, and the first end of the first steam supply regulating valve are respectively connected to the second input end of the first heat network heating unit. The second end of the first steam supply stop valve is connected to the input end of the first back-pressure power generation unit. The second end of the first steam supply regulating valve is connected to the third input end of the first heat network heating unit.

[0023] In a possible implementation manner of the first aspect, the first back-pressure power generation unit includes: a first back-pressure steam turbine, a first back-pressure generator, and a first back-pressure generator condenser;

[0024] The input end of the first back-pressure steam turbine is connected to the first output end of the first extraction steam supply unit from the middle extraction. The output end of the first back-pressure steam turbine is connected to the input end of the first back-pressure generator. The first back-pressure steam turbine is used to generate mechanical energy based on the first extraction steam from the middle extraction. The output end of the first back-pressure generator is connected to the first input end of the first back-pressure generator condenser. The first back-pressure generator is used to generate electricity based on the mechanical energy generated by the first back-pressure steam turbine;

[0025] The second input end of the first back-pressure generator condenser is connected to the first output end of the high back-pressure heating unit. The output end of the first back-pressure generator condenser is respectively connected to the output end of the second back-pressure power generation unit and the first input end of the first heat network heating unit. The first back-pressure generator condenser is used to cool the exhaust steam of the first back-pressure generator and recover energy.

[0026] In a possible implementation manner of the first aspect, the first heat network heating unit includes: a first heat network circulating water pump steam turbine and a first heat network heater;

[0027] The input end of the first heat network circulating water pump steam turbine is connected to the third output end of the first extraction steam supply unit from the middle extraction. The output end of the first heat network circulating water pump steam turbine is connected to the third input end of the first heat network heater. The first heat network circulating water pump steam turbine is used to drive the first heat network heater;

[0028] The first input end of the first heat network heater is connected to the output end of the first back-pressure power generation unit. The second input end of the first heat network heater is connected to the second output end of the first extraction steam supply unit from the middle extraction. The output end of the first heat network heater outputs heat network supply water. The first heat network heater is used to reheat the heat network return water heated by the high back-pressure heating unit based on the first extraction steam from the middle extraction and output the reheated heat network return water.

[0029] In a possible implementation of the first aspect, the second intermediate extraction steam supply unit includes: a second intermediate pressure cylinder and a second intermediate extraction steam control module;

[0030] The first end of the second intermediate extraction steam control module is respectively connected to the exhaust outlet of the second intermediate pressure cylinder and the first end of the exhaust steam flow regulating unit. The second end of the second intermediate extraction steam control module is connected to the input end of the second back-pressure power generation unit. The third end of the second intermediate extraction steam control module is connected to the second input end of the second heat network heating unit. The second intermediate extraction steam control module is used to control the second intermediate extraction steam.

[0031] In a possible implementation of the first aspect, the second intermediate extraction steam control module includes: a second pneumatic check valve, a second hydraulic quick-closing regulating valve, a second electric shut-off valve, a second steam supply gate valve, a second steam supply regulating valve, a second main steam supply pipeline provided between the exhaust outlet of the second intermediate pressure cylinder and the second input end of the second heat network heating unit, and a third bypass steam supply pipeline provided between the second end of the second electric shut-off valve and the input end of the second back-pressure power generation unit;

[0032] The second pneumatic check valve, the second hydraulic quick-closing regulating valve, the second electric shut-off valve, and the second steam supply regulating valve are sequentially arranged on the second main steam supply pipeline. The second steam supply gate valve is arranged on the third bypass steam supply pipeline. The second end of the second pneumatic check valve is connected to the first end of the second hydraulic quick-closing regulating valve. The second end of the second hydraulic quick-closing regulating valve is connected to the first end of the second electric shut-off valve. The second end of the second electric shut-off valve and the first end of the second steam supply gate valve are respectively connected to the first end of the second steam supply regulating valve. The second end of the second steam supply gate valve is connected to the input end of the second back-pressure power generation unit. The second end of the second steam supply regulating valve is connected to the second input end of the second heat network heating unit.

[0033] In a possible implementation of the first aspect, the exhaust steam flow regulating unit includes a connecting pipe hydraulic butterfly valve; the connecting pipe hydraulic butterfly valve is arranged on the second exhaust steam pipeline. The first end of the connecting pipe hydraulic butterfly valve is connected to the third output end of the second intermediate extraction steam supply unit. The second end of the connecting pipe hydraulic butterfly valve is connected to the steam inlet of the second low-pressure cylinder.

[0034] In a possible implementation of the first aspect, the high back-pressure heating unit includes a high back-pressure condenser; the first input end of the high back-pressure condenser is connected to the second exhaust outlet of the second low-pressure cylinder. The second input end of the high back-pressure condenser inputs heat network return water. The first output end of the high back-pressure condenser is respectively connected to the second input end of the first back-pressure power generation unit and the second input end of the second back-pressure power generation unit through a heat network circulating water pipeline. The second output end of the high back-pressure condenser is connected to the input end of the exhaust steam device.

[0035] In a possible implementation of the first aspect, the second back-pressure power generation unit includes: a second back-pressure steam turbine, a second back-pressure generator, and a second back-pressure generator condenser;

[0036] The input end of the second back-pressure steam turbine is connected to the first output end of the second extraction steam supply unit in the middle row, the output end of the second back-pressure steam turbine is connected to the input end of the second back-pressure generator, and the second back-pressure steam turbine is used to generate mechanical energy based on the second extraction steam in the middle row; the output end of the second back-pressure generator is connected to the first input end of the second back-pressure generator condenser, and the second back-pressure generator is used to generate electricity based on the mechanical energy generated by the second back-pressure steam turbine;

[0037] The second input end of the second back-pressure generator condenser is connected to the first output end of the high back-pressure heating unit, and the output end of the second back-pressure generator condenser is respectively connected to the output end of the first back-pressure power generation unit and the first input end of the second heat network heating unit. The second back-pressure generator condenser is used to cool the exhaust steam of the second back-pressure generator and recover energy.

[0038] In a possible implementation of the first aspect, the second heat network heating unit includes: a second small steam turbine for the heat network circulating pump and a second heat network heater;

[0039] The input end of the second small steam turbine for the heat network circulating pump is connected to the second output end of the second extraction steam supply unit in the middle row, the output end of the second small steam turbine for the heat network circulating pump is connected to the second input end of the second heat network heater, and the second small steam turbine for the heat network circulating pump is used to drive the second heat network heater;

[0040] The first input end of the second heat network heater is connected to the output end of the first back-pressure power generation unit, and the output end of the second heat network heater outputs heat network supply water. The second heat network heater is used to reheat the heat network return water heated by the high back-pressure heating unit and output the reheated heat network return water.

[0041] In a possible implementation of the first aspect, the device further includes a heat network circulating water driving unit;

[0042] The input end of the heat network circulating water driving unit is connected to the output ends of the first back-pressure power generation unit and the second back-pressure power generation unit through a heat network circulating water pipeline. The first output end of the heat network circulating water driving unit is connected to the first input end of the first heat network heating unit through a heat network circulating water pipeline. The second output end of the heat network circulating water driving unit is connected to the first input end of the second heat network heating unit through a heat network circulating water pipeline. The heat network circulating water driving unit is used to provide power for the circulation of the heat network return water.

[0043] In a possible implementation of the first aspect, the heat network circulating water driving unit includes a heat network circulating pump;

[0044] The input end of the heat network circulating water pump is connected to the output ends of the first back-pressure power generation unit and the second back-pressure power generation unit through the heat network circulating water pipeline. The first output end of the heat network circulating water pump is connected to the first input end of the first heat network heating unit through the heat network circulating water pipeline. The second output end of the heat network circulating water pump is connected to the first input end of the second heat network heating unit through the heat network circulating water pipeline.

[0045] In a second aspect, an embodiment of the present application provides a cogeneration system for low-pressure cylinder micro-output combined with high back-pressure transformation, which includes: a first air-cooled island, a second air-cooled island, a heat network return water supply device, an exhaust device, a first heat network water supply device, a second heat network water supply device, and a cogeneration device for low-pressure cylinder micro-output combined with high back-pressure transformation according to any one of the first aspects;

[0046] The first input end of the cogeneration device is connected to the output end of the heat network return water supply device. The first output end of the cogeneration device is connected to the input end of the first air-cooled island. The first air-cooled island is used to reduce the exhaust steam temperature of the first low-pressure cylinder so that the exhaust steam of the first low-pressure cylinder condenses into water. The second output end of the cogeneration device is connected to the input end of the second air-cooled island. The second air-cooled island is used to reduce the exhaust steam temperature of the second low-pressure cylinder so that the exhaust steam of the second low-pressure cylinder condenses into water.

[0047] The third output end of the cogeneration device is connected to the input end of the exhaust device. The exhaust device is used to discharge the exhaust steam of the high back-pressure heating unit. The fourth output end of the cogeneration device is connected to the input end of the first heat network water supply device. The first heat network water supply device is used to provide heat network water supply to users. The fifth output end of the cogeneration device is connected to the input end of the second heat network water supply device. The second heat network water supply device is used to provide heat network water supply to users. The cogeneration device is used for power generation and heating supply to users.

[0048] In the cogeneration device for low-pressure cylinder micro-output combined with high back-pressure transformation of the present application, the first middle extraction steam supply unit is used to provide the first middle extraction steam. The low-pressure cylinder output adjustment unit is used to reduce the output of the first low-pressure cylinder. The first back-pressure power generation unit is used for power generation and heating based on the first middle extraction steam, reducing the use of high-grade heat at a lower grade. The first heat network heating unit is used to secondarily heat the preliminarily heated heat network return water based on the first middle extraction steam.

[0049] The second middle extraction steam supply unit is used to provide the second middle extraction steam. The exhaust steam flow regulation unit is used to adjust the exhaust steam flow to enable the second cogeneration unit to switch operations under different working conditions, respond to the peak shaving demands during different heating periods of the system, and improve the peak shaving flexibility. The high backpressure heating unit is used to preliminarily heat the return water of the heat network to achieve low-grade waste heat heating. The second backpressure power generation unit is used to generate electricity and heat based on the second middle extraction steam, reducing the use of high-grade heat at a lower grade. The second heat network heating unit is used to secondarily heat the return water of the heat network that has been heated by the high backpressure heating unit.

[0050] The solution of this application can improve the thermal efficiency, waste heat utilization rate, energy utilization rate, and peak shaving flexibility of the cogeneration unit while responding to the peak shaving demands during different heating periods of the system, and has strong usability and practicality.

[0051] Other features and advantages of this application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0053] Figure 1 It is a schematic block diagram of the overall structure of the cogeneration device 100 with low-pressure cylinder micro-output combined with high backpressure transformation provided by the embodiment of this application;

[0054] Figure 2 It is a schematic block diagram of the specific structure of the cogeneration device 100 with low-pressure cylinder micro-output combined with high backpressure transformation provided by the embodiment of this application;

[0055] Figure 3 It is a schematic block diagram of the cogeneration system 200 with low-pressure cylinder micro-output combined with high backpressure transformation provided by the embodiment of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0056] In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of this application. However, those skilled in the art should clearly understand that this application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of this application.

[0057] It should be understood that, as used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or their groups.

[0058] It should also be understood that the terminology used in this specification of the present application is for the purpose of describing particular embodiments only and is not intended to limit the present application. As used in this specification of the present application and the appended claims, unless the context clearly dictates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0059] It should be further understood that the term "and / or" used in this specification of the present application and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0060] As used in this specification and the appended claims, the term "if" can be interpreted, depending on the context, as "when", or "once", or "in response to determining", or "in response to detecting". Similarly, the phrase "if determined" or "if [the described condition or event] is detected" can be interpreted, depending on the context, as meaning "once determined", or "in response to determining", or "once [the described condition or event] is detected", or "in response to detecting [the described condition or event]".

[0061] In addition, in the description of the present application, the terms "first", "second", "third", etc. are used only for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0062] Reference to "one embodiment" or "some embodiments" or the like described in this specification of the present application means that a particular feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of the present application. Thus, statements such as "in one embodiment", "in some embodiments", "in some other embodiments", "in still some other embodiments", etc. that appear in different places in this specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "comprising", "including", "having", and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0063] In this specification of the present application, unless otherwise stated, the orientation terms such as "upper", "lower", "left", "right" generally refer to the orientation or positional relationship based on the orientation shown in the drawings, or the orientation or positional relationship in which the product of this application is usually placed during use.

[0064] In the description of this application, it should also be noted that unless otherwise clearly specified and defined, the terms "set", "installed", "connected", and "linked" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0065] In recent years, against the backdrop of the accelerating energy transformation in China and the implementation of the "dual carbon" goal, new energy in China has developed rapidly. However, this has also posed unprecedented challenges to the safety and stability of the power system. Especially in resource-rich areas of new energy in western and northern China, the contradiction between the huge total amount of clean energy resources and the insufficient existing regulation capacity is particularly prominent. China urgently needs to promote the construction of new coal-fired power units around enhancing the flexibility and dynamic adaptability of the power system to overcome the problem of power consumption. Among them, the flexibility of the power system generally refers to the ability of the power system to maintain the dynamic balance of power supply and demand and economically deploy various flexibility resources to cope with the uncertainties of power sources, power grids, and loads.

[0066] At present, the cogeneration technology plays an indispensable role in ensuring people's livelihood heating. Promoting the flexibility transformation of existing coal-fired power units, especially cogeneration units, has become a top priority. Using different thermal power decoupling technologies to improve the flexibility of the units is a relatively effective technical approach. Cogeneration is a poly-generation energy system that integrates the heating and power generation processes for efficient energy utilization, which can significantly improve the energy utilization rate.

[0067] Essentially, thermal power decoupling is to use other heat sources to replace the steam turbine for heating, reduce the heating power of the steam turbine, and thus reduce the power generation power determined by heat. By adding equipment such as hot water storage tanks and electric boilers (storing thermal energy or directly converting electrical energy into thermal energy) or modifying the steam transmission process, the unit can not only meet the heat load demand but also participate in deep peak shaving of the power grid, thereby effectively improving the operation flexibility of the cogeneration unit.

[0068] In the prior art, the thermoelectric decoupling technology mainly includes: configuring a heat storage water tank for heating, configuring an electric boiler for heating, removing the low-pressure cylinder for heating (heating with zero output of the low-pressure cylinder), high back-pressure transformation for heating, bypass heating of the high and intermediate pressure cylinders, and recovering waste heat from the circulating water for heating, etc. Configuring a heat storage water tank for heating is to set up a heat storage tank system on the heat network side for heating, weakening the time coupling degree of the heat-electric load; configuring an electric boiler for heating is to convert electrical energy into heat energy by means of electric heating; removing the low-pressure cylinder for heating is to cut off all the steam inlet of the low-pressure cylinder, making the low-pressure cylinder "zero output" and operating in a back-pressure heating mode under vacuum conditions; high back-pressure transformation for heating is to increase the back pressure to increase the circulating water temperature for heating; bypass heating of the high and intermediate pressure cylinders is to use the bypass steam supply pipeline of the high and intermediate pressure cylinders to reduce the temperature and pressure of part of the high-quality steam and then use it for heating; recovering waste heat from the circulating water for heating is to use an absorption heat pump to extract part of the steam to drive the heat pump to recover the waste heat of the circulating water and enhance the heating capacity of the unit.

[0069] A large number of studies on the thermoelectric decoupling flexibility transformation of cogeneration units focus on the transformation characteristics and effects of individual technologies, and there are few studies on combining multiple technologies to meet the heating requirements of cogeneration units. Each of the general thermoelectric decoupling technologies also has certain disadvantages: the heat storage water tank has a large floor area and a weak adaptability to long-term low-load peak shaving of the system; the investment in electric boilers is high, the energy utilization efficiency is low, and the applicability is poor; removing the low-pressure cylinder has risks such as blade dynamic stress, drum wind, and water erosion that affect the safe operation of the unit and cannot meet the peak shaving requirements of continuously tracking fluctuating power generation loads; the flexibility transformation of high back-pressure transformation is not thorough enough; there are throttling losses in bypass heating of the high and intermediate pressure cylinders; the flexibility of recovering waste heat from the circulating water is poor.

[0070] Traditional cogeneration units use the extraction steam from the intermediate pressure cylinder for heating during extraction steam heating. The cold source loss of the exhaust steam of the low-pressure cylinder cannot be fully utilized, and a large amount of extraction steam from the middle extraction (the exhaust steam extraction of the intermediate pressure cylinder of the steam turbine) is only used for heating, and the high-quality heat is degraded for use, and the energy utilization rate is also low. In addition, the peak shaving flexibility of traditional cogeneration units is poor. Therefore, carrying out research on new coupling technologies has great potential and important significance for adapting to the flexibility transformation of cogeneration units.

[0071] As can be seen from the above, how to improve the thermal efficiency, waste heat utilization rate, energy utilization rate, and peak shaving flexibility of cogeneration units has become a problem to be solved.

[0072] In view of the above defects, the embodiment of the present application provides a cogeneration device with low-pressure cylinder micro-output combined with high back-pressure transformation. The first middle extraction steam supply unit is used to provide the first middle extraction steam, the low-pressure cylinder output adjustment unit is used to reduce the output of the first low-pressure cylinder, the first back-pressure power generation unit is used to generate electricity and heat based on the first middle extraction steam, reducing the degradation of high-quality heat for use, and the first heat network heating unit is used to secondary heat the preliminarily heated heat network return water based on the first middle extraction steam.

[0073] The second middle extraction steam supply unit is used to provide the second middle extraction steam. The exhaust steam flow regulating unit is used to make the second cogeneration unit switch operations under different working conditions by regulating the exhaust steam flow, which can respond to the peak shaving demands during different heating periods of the system and improve the peak shaving flexibility. The high back-pressure heating unit is used to realize low-grade waste heat heating based on the preliminary heating of the return water of the heat network. The second back-pressure power generation unit is used to generate electricity and heat based on the second middle extraction steam, reducing the use of high-grade heat at a degraded level. The second heat network heating unit is used to secondary heat the return water of the heat network that has been heated by the high back-pressure heating unit.

[0074] The solution of this application realizes the cascade utilization of energy and makes full use of the waste heat of the cogeneration unit by coupling different thermoelectric decoupling technologies, that is, the coupling of the low-pressure cylinder micro-output and the high back-pressure transformation, and on this basis, carrying out the cascade utilization of energy and the heating transformation design for the cogeneration unit. While responding to the peak shaving demands during different heating periods of the unit, it can improve the thermal efficiency, regulation efficiency, waste heat utilization rate, energy utilization rate and safety of the thermoelectric regulation of the cogeneration unit, making the cogeneration unit more flexible. It has important significance and engineering application value for the flexible transformation of the thermoelectric decoupling of the cogeneration unit in the thermal power field, and has strong usability and practicality.

[0075] The overall structure of the cogeneration device with combined low-pressure cylinder micro-output and high back-pressure transformation provided by the embodiments of this application is introduced below through specific embodiments.

[0076] Please refer to Figure 1 , Figure 1 which is a schematic block diagram of the overall structure of the cogeneration device 100 with combined low-pressure cylinder micro-output and high back-pressure transformation provided by the embodiments of this application. As Figure 1 shown, the cogeneration device 100 with combined low-pressure cylinder micro-output and high back-pressure transformation includes: the first middle extraction steam supply unit 111 of the first cogeneration unit Z1, the low-pressure cylinder output regulating unit 112, the first low-pressure cylinder 2, the first back-pressure power generation unit 113, the first heat network heating unit 114, and the first exhaust steam pipeline arranged between the fourth output end (the fourth exhaust steam outlet) of the first middle extraction steam supply unit 111 and the steam inlet of the first low-pressure cylinder 2; the second middle extraction steam supply unit 115 of the second cogeneration unit Z2, the exhaust steam flow regulating unit 116, the second low-pressure cylinder 10, the high back-pressure heating unit 117, the second back-pressure power generation unit 118, the second heat network heating unit 119, and the second exhaust steam pipeline arranged between the third output end of the second middle extraction steam supply unit 115 and the steam inlet of the second low-pressure cylinder 10.

[0077] Among them, the first cogeneration unit Z1 is used for the micro-output transformation of the first low-pressure cylinder 2, and the second cogeneration unit Z2 is used for the high back-pressure transformation.

[0078] In one embodiment, the first output end (the first extraction steam outlet) of the first intermediate extraction steam supply unit 111 is connected to the first input end of the first back-pressure power generation unit 113, the second output end (the second extraction steam outlet) of the first intermediate extraction steam supply unit 111 is connected to the second input end of the first heat network heating unit 114, the third output end (the third extraction steam outlet) of the first intermediate extraction steam supply unit 111 is connected to the third input end of the first heat network heating unit 114, and the fourth output end of the first intermediate extraction steam supply unit 111 is connected to the first end of the low-pressure cylinder output regulating unit 112. The first intermediate extraction steam supply unit 111 is configured to supply the first intermediate extraction steam to the first back-pressure power generation unit 113 and the first heat network heating unit 114.

[0079] In one embodiment, the low-pressure cylinder output regulating unit 112 is arranged on the first extraction steam pipeline. The second end of the low-pressure cylinder output regulating unit 112 is connected to the steam inlet of the first low-pressure cylinder 2. The extraction steam outlet of the first low-pressure cylinder 2 is connected to the input end of the first air-cooled island 210. The first low-pressure cylinder 2 discharges steam to the first air-cooled island 210. The first air-cooled island 210 is configured to reduce the extraction steam temperature of the first low-pressure cylinder 2 through an air cooling system, so that the extraction steam of the first low-pressure cylinder 2 is condensed into water for recycling. The low-pressure cylinder output regulating unit 112 is configured to reduce the output of the first low-pressure cylinder 2 and regulate it to a very low output, that is, the output is very small and less than a preset output threshold.

[0080] Wherein, the preset output threshold can be determined according to the specific situation in the actual application scenario and is not specifically limited herein. The output of the first low-pressure cylinder 2 is regulated by adjusting the flow rate and pressure of the extraction steam discharged by the first intermediate extraction steam supply unit 111. At the same time, the low-pressure cylinder output regulating unit 112 can also prevent the reverse flow of the extraction steam discharged by the first intermediate extraction steam supply unit 111 and convert the flow direction of the extraction steam discharged by the first intermediate extraction steam supply unit 111.

[0081] In one embodiment, the second input end of the first back-pressure power generation unit 113 is connected to the first output end of the high back-pressure heating unit 117. The output end of the first back-pressure power generation unit 113 is respectively connected to the output end of the second back-pressure power generation unit 118 and the first input end of the first heat network heating unit 114. The first back-pressure power generation unit 113 is configured to generate electricity and supply heat based on the first intermediate extraction steam. A large amount of intermediate extraction steam of traditional combined heat and power units is only used for heating, while the first intermediate extraction steam in this embodiment can be used for both heating and power supply, thereby reducing the use of high-grade heat at a lower grade.

[0082] In one embodiment, the output end of the first heat network heating unit 114 outputs heat network supply water. The first heat network heating unit 114 is configured to perform secondary heating on the heat network return water preliminarily heated by the high back-pressure heating unit 117 based on the first intermediate extraction steam and output the heated heat network return water. The heated heat network return water is used to supply heat to users.

[0083] In one embodiment, the first output end of the second intermediate extraction steam supply unit 115 is connected to the first input end of the second back-pressure power generation unit 118, the second output end of the second intermediate extraction steam supply unit 115 is connected to the second input end of the second heat network heating unit 119, and the third output end of the second intermediate extraction steam supply unit 115 is connected to the first end of the exhaust steam flow regulating unit 116. The second intermediate extraction steam supply unit 115 is used to supply the second intermediate extraction steam to the second back-pressure power generation unit 118 and the second heat network heating unit 119.

[0084] In one embodiment, the exhaust steam flow regulating unit 116 is arranged on the second exhaust steam pipeline. The second end of the exhaust steam flow regulating unit 116 is connected to the steam inlet of the second low-pressure cylinder 10. The first exhaust steam outlet of the second low-pressure cylinder 10 is connected to the input end of the second air-cooled island 220. The second air-cooled island 220 is used to reduce the exhaust steam temperature of the second low-pressure cylinder 10 through an air cooling system so that the exhaust steam of the second low-pressure cylinder 10 is condensed into water for recycling. The exhaust steam flow regulating unit 116 is used to regulate the exhaust steam flow input to the second low-pressure cylinder 10 so that the second cogeneration unit Z2 can switch between pure condensing, extraction condensing or back-pressure operating conditions. The exhaust steam flow regulating unit 116 is also used to regulate the exhaust steam pressure, prevent reverse flow, change the exhaust steam flow direction and protect the pipeline system.

[0085] Among them, in the pure condensing condition, all steam is used for power generation; the extraction condensing condition combines the functions of pure condensing and heat supply, so that a part of the steam is used for power generation and the other part is used for heat supply or other purposes; in the back-pressure condition, the exhaust steam of the steam turbine is all supplied to other steam turbines or users.

[0086] In one embodiment, the first input end (exothermic side inlet) of the high back-pressure heating unit 117 is connected to the second exhaust steam outlet of the second low-pressure cylinder 10, and the second input end (endothermic side inlet) of the high back-pressure heating unit 117 inputs the return water of the heat network. The second output end of the high back-pressure heating unit 117 is connected to the input end of the exhaust steam device 240, and the high back-pressure heating unit 117 exhausts steam to the exhaust steam device 240. The high back-pressure heating unit 117 is used to preliminarily heat the return water of the heat network based on the exhaust steam of the second low-pressure cylinder 10 to achieve low-grade waste heat heating. The high back-pressure heating unit 117 can heat the return water of the heat network from 30 - 40 °C to about 70.5 °C.

[0087] Among them, the high back-pressure heating unit 117 can increase the back pressure of the second low-pressure cylinder 10 to increase the temperature of the return water of the heat network.

[0088] In one embodiment, the second input end of the second back-pressure power generation unit 118 is connected to the first output end of the high back-pressure heating unit 117, the output end of the second back-pressure power generation unit 118 is connected to the first input end of the second heat network heating unit 119, and the second back-pressure power generation unit 118 is used for generating electricity and supplying heat based on the second extraction steam from the intermediate stage. A large amount of the extraction steam from the intermediate stage of traditional combined heat and power units is only used for heat supply, while the second extraction steam from the intermediate stage in this embodiment can be used for both heat supply and power generation, thereby reducing the degradation of high-grade heat for use.

[0089] In one embodiment, the output end of the second heat network heating unit 119 outputs heat network supply water. The second heat network heating unit 119 is used for secondary heating of the heat network return water heated by the high back-pressure heating unit 117 based on the second extraction steam from the intermediate stage, and outputs the heated heat network return water, and the heated heat network return water is used for heating users.

[0090] This embodiment realizes cascade utilization of energy and makes full use of the waste heat of the combined heat and power unit by coupling different heat and power decoupling technologies, that is, the coupling of the micro-output of the low-pressure cylinder and the high back-pressure transformation, and on this basis, carrying out cascade energy utilization and heating transformation design for the combined heat and power unit. While responding to the peak shaving requirements during different heating periods of the unit, it can improve the thermal efficiency, regulation efficiency, waste heat utilization rate, energy utilization rate and safety of the combined heat and power unit for thermoelectric regulation, enabling the combined heat and power unit to have higher flexibility, which has important significance and engineering application value for the flexible transformation of the combined heat and power unit in the thermal power field, and has strong usability and practicality.

[0091] The following introduces the specific structure of the combined heat and power device 100 with micro-output of the low-pressure cylinder combined with high back-pressure transformation provided by the embodiments of the present application through specific embodiments.

[0092] Please refer to Figure 2 , Figure 2 which is a schematic block diagram of the specific structure of the combined heat and power device 100 with micro-output of the low-pressure cylinder combined with high back-pressure transformation provided by the embodiments of the present application. As Figure 2 shown, the first extraction steam supply unit 111 from the intermediate stage includes: a first intermediate-pressure cylinder 1 and a first extraction steam control module (valve group) 1112.

[0093] In one embodiment, the first end of the first intermediate extraction steam control module 1112 is respectively connected to the extraction steam outlet of the first intermediate pressure cylinder 1 and the first end of the low-pressure cylinder output regulation unit 112. The second end of the first intermediate extraction steam control module 1112 is connected to the input end of the first back-pressure power generation unit 113. The third end of the first intermediate extraction steam control module 1112 is connected to the second input end of the first heat network heating unit 114. The fourth end of the first intermediate extraction steam control module 1112 is connected to the third input end of the first heat network heating unit 114. The first intermediate extraction steam control module 1112 is used to control the first intermediate extraction steam.

[0094] Among them, the first intermediate pressure cylinder 1 is used to further expand the low-temperature and low-pressure steam of the high-pressure cylinder, increasing the specific volume and temperature of the steam. The first low-pressure cylinder 2 is used to further expand the low-temperature and low-pressure steam of the first intermediate pressure cylinder 1, further increasing the specific volume of the steam, thereby improving the total efficiency of the steam turbine.

[0095] In one embodiment, the low-pressure cylinder output regulation unit 112 includes a double-disc heat supply butterfly valve 3. The double-disc heat supply butterfly valve 3 is arranged on the first extraction steam pipeline. The first end of the double-disc heat supply butterfly valve 3 is connected to the fourth output end of the first intermediate extraction steam supply unit 111. The second end of the double-disc heat supply butterfly valve 3 is connected to the steam inlet of the first low-pressure cylinder 2.

[0096] It should be noted that in this embodiment, no major modification is made to the body of the first low-pressure cylinder 2. Instead, the form of the steam inlet butterfly valve of the first low-pressure cylinder 2 is optimized to enable the first low-pressure cylinder 2 to maintain a relatively low steam inlet flow rate and a relatively low back pressure operation, making the most of the first intermediate extraction steam for heating and having a strong low-load peak shaving ability.

[0097] In one embodiment, the first intermediate extraction steam control module 1112 includes: a first pneumatic check valve 19, a first hydraulic quick-closing regulating valve 20, a first electric shut-off valve 21, a first steam supply gate valve 22, a first steam supply regulating valve 23, a first main steam supply pipeline arranged between the extraction steam outlet of the first intermediate pressure cylinder 1 and the second input end of the first heat network heating unit 114, a first bypass steam supply pipeline arranged between the second end of the first electric shut-off valve 21 and the input end of the first back-pressure power generation unit 113, and a second bypass steam supply pipeline arranged between the second end of the first electric shut-off valve 21 and the third input end of the first heat network heating unit 114.

[0098] In one embodiment, the first pneumatic check valve 19, the first hydraulic quick-closing regulating valve 20, and the first electric shut-off valve 21 are sequentially arranged on the first main steam supply pipeline. The first steam supply gate valve 22 is arranged on the first bypass steam supply pipeline. The first steam supply regulating valve 23 is arranged on the second bypass steam supply pipeline.

[0099] In one embodiment, the first end of the first pneumatic check valve 19 is connected to the first end of the low-pressure cylinder output regulating unit 112. The second end of the first pneumatic check valve 19 is connected to the first end of the first hydraulic quick-closing regulating valve 20. The second end of the first hydraulic quick-closing regulating valve 20 is connected to the first end of the first electric shut-off valve 21. The second end of the first electric shut-off valve 21, the first end of the first steam supply gate valve 22, and the first end of the first steam supply regulating valve 23 are respectively connected to the second input end of the first heat network heating unit 114. The second end of the first steam supply gate valve 22 is connected to the input end of the first back-pressure power generation unit 113. The second end of the first steam supply regulating valve 23 is connected to the third input end of the first heat network heating unit 114.

[0100] Among them, the first pneumatic check valve 19 is used to prevent the reverse flow of the first extraction steam from the intermediate stage. The first hydraulic quick-closing regulating valve 20 is used to regulate the flow rate, pressure, and liquid level of the first extraction steam from the intermediate stage, and at the same time has the function of quickly closing. The first electric shut-off valve 21 is used to control the on-off of the first extraction steam from the intermediate stage, that is, to control the flow of the first extraction steam from the intermediate stage. The first steam supply gate valve 22 is used to cut off the flow of the first extraction steam from the intermediate stage. The first steam supply regulating valve 23 is used to regulate various process parameters such as the flow rate, pressure, and temperature of the first extraction steam from the intermediate stage.

[0101] It should be noted that the specific types and materials of the first pneumatic check valve 19, the first hydraulic quick-closing regulating valve 20, the first electric shut-off valve 21, the first steam supply gate valve 22, and the first steam supply regulating valve 23 can be reasonably determined according to factors such as the scale of the first combined heat and power unit Z1, the pipeline size, material, and steam parameters under the actual heating conditions.

[0102] In one embodiment, the first back-pressure power generation unit 113 includes: a first back-pressure steam turbine 4, a first back-pressure generator 5, and a first back-pressure generator condenser 6. The input end (steam inlet) of the first back-pressure steam turbine 4 is connected to the first output end of the first extraction steam supply unit 111 from the intermediate stage. The output end (exhaust outlet) of the first back-pressure steam turbine 4 is connected to the input end of the first back-pressure generator 5. The first back-pressure steam turbine 4 is used to generate mechanical energy based on the first extraction steam from the intermediate stage, and the first back-pressure steam turbine 4 can also be used for heating. The output end (exhaust outlet) of the first back-pressure generator 5 is connected to the first input end (steam inlet) of the first back-pressure generator condenser 6. The first back-pressure generator 5 exhausts steam to the first back-pressure generator condenser 6. The first back-pressure generator 5 is used to generate electricity based on the mechanical energy generated by the first back-pressure steam turbine 4. After the first back-pressure generator 5 generates electricity, the back pressure of the first combined heat and power unit Z1 rises to 34 kPa.

[0103] In one embodiment, the second input end of the first back-pressure generator condenser 6 is connected to the first output end of the high back-pressure heating unit 117, and the output end of the first back-pressure generator condenser 6 is respectively connected to the output end of the second back-pressure power generation unit 118 and the first input end of the first heat network heating unit 114. The first back-pressure generator condenser 6 is used to cool the exhaust steam of the first back-pressure generator 5, that is, to condense the high-temperature and high-pressure steam discharged from the first back-pressure generator 5 into water, which is achieved through the heat exchange between the cooling water and the condensed water. The first back-pressure generator condenser 6 is also used for energy recovery, that is, to recover the heat energy in the steam and convert it into electric energy. By condensing the steam back into water, the heat energy in the steam is converted into electric energy, improving the energy utilization efficiency.

[0104] In one embodiment, the first heat network heating unit 114 includes: a first heat network circulating water pump steam turbine 7 and a first heat network heater 8. The input end (steam inlet) of the first heat network circulating water pump steam turbine 7 is connected to the third output end of the first intermediate extraction steam supply unit 111, the output end of the first heat network circulating water pump steam turbine 7 is connected to the third input end of the first heat network heater 8, and the first heat network circulating water pump steam turbine 7 is used to drive the first heat network heater 8. The exhaust steam of the first heat network circulating water pump steam turbine 7 can enter the first heat network heater 8 to realize the recovery and utilization of heat, further improving the energy utilization efficiency. The first intermediate extraction steam supplies the driving steam source for the first heat network circulating water pump steam turbine 7 and supplies heat to the first heat network heater 8.

[0105] In one embodiment, the first input end of the first heat network heater 8 is connected to the output end of the first back-pressure power generation unit 113, the second input end of the first heat network heater 8 is connected to the second output end of the first intermediate extraction steam supply unit 111, and the output end of the first heat network heater 8 outputs heat network supply water. The first heat network heater 8 is used to secondarily heat the heat network return water heated by the high back-pressure heating unit 117 based on the first intermediate extraction steam and output the heated heat network return water.

[0106] In one embodiment, the second intermediate extraction steam supply unit 115 includes: a second intermediate pressure cylinder 9 and a second intermediate extraction steam control module (valve group) 1152. The first end of the second intermediate extraction steam control module 1152 is respectively connected to the exhaust steam outlet of the second intermediate pressure cylinder 9 and the first end of the exhaust steam flow regulation unit 116, the second end of the second intermediate extraction steam control module 1152 is connected to the input end of the second back-pressure power generation unit 118, and the third end of the second intermediate extraction steam control module 1152 is connected to the second input end of the second heat network heating unit 119. The second intermediate extraction steam control module 1152 is used to control the second intermediate extraction steam.

[0107] Among them, the second intermediate-pressure cylinder 9 is used to further expand the low-temperature and low-pressure steam of the high-pressure cylinder, increasing the specific volume and temperature of the steam. The second low-pressure cylinder 10 is used to further expand the low-temperature and low-pressure steam of the second intermediate-pressure cylinder 9, further increasing the specific volume of the steam, thereby improving the overall efficiency of the steam turbine.

[0108] In one embodiment, the second extraction steam control module 1152 includes: a second pneumatic check valve 24, a second hydraulic quick-closing regulating valve 25, a second electric shut-off valve 26, a second steam supply gate valve 27, a second steam supply regulating valve 28, a second main steam supply pipeline disposed between the exhaust outlet of the second intermediate-pressure cylinder 9 and the second input end of the second heat network heating unit 119, and a third bypass steam supply pipeline disposed between the second end of the second electric shut-off valve 26 and the input end of the second back-pressure power generation unit 118.

[0109] In one embodiment, the second pneumatic check valve 24, the second hydraulic quick-closing regulating valve 25, the second electric shut-off valve 26, and the second steam supply regulating valve 28 are sequentially disposed on the second main steam supply pipeline, and the second steam supply gate valve 27 is disposed on the third bypass steam supply pipeline. The second end of the second pneumatic check valve 24 is connected to the first end of the second hydraulic quick-closing regulating valve 25, the second end of the second hydraulic quick-closing regulating valve 25 is connected to the first end of the second electric shut-off valve 26, and the second ends of the second electric shut-off valve 26 and the second steam supply gate valve 27 are respectively connected to the first end of the second steam supply regulating valve 28. The second end of the second steam supply gate valve 27 is connected to the input end of the second back-pressure power generation unit 118, and the second end of the second steam supply regulating valve 28 is connected to the second input end of the second heat network heating unit 119.

[0110] Among them, the second pneumatic check valve 24 is used to prevent the reverse flow of the second extraction steam. The second hydraulic quick-closing regulating valve 25 is used to regulate the flow rate, pressure, and liquid level of the second extraction steam, and at the same time has the function of quick closing. The second electric shut-off valve 26 is used to control the on-off of the second extraction steam, that is, to control the flow of the second extraction steam. The second steam supply gate valve 27 is used to switch and cut off the flow of the second extraction steam. The second steam supply regulating valve 28 is used to regulate various process parameters such as the flow rate, pressure, and temperature of the second extraction steam.

[0111] It should be noted that the specific type selection and materials of the second pneumatic check valve 24, the second hydraulic quick-closing regulating valve 25, the second electric shut-off valve 26, and the second steam supply regulating valve 28 can be reasonably determined according to factors such as the scale of the second cogeneration unit Z2, the pipeline size, materials, and steam parameters under the actual heating conditions.

[0112] In one embodiment, the exhaust steam flow regulating unit 116 includes a connecting pipe hydraulic butterfly valve 11. The connecting pipe hydraulic butterfly valve 11 is arranged on the second exhaust steam pipeline. The first end of the connecting pipe hydraulic butterfly valve 11 is connected to the third output end of the second intermediate extraction steam supply unit 115, and the second end of the connecting pipe hydraulic butterfly valve 11 is connected to the steam inlet of the second low-pressure cylinder 10. The connecting pipe hydraulic butterfly valve 11 has good flow characteristics, with continuously adjustable flow rate, and can be adjusted and controlled within the flow range of 0 to 100%. According to the actual peak shaving requirements, the second cogeneration unit Z2 can flexibly switch between the pure condensing, extraction condensing, and back pressure operating conditions.

[0113] In one embodiment, based on different peak shaving and heating demands, the second cogeneration unit Z2 can flexibly adjust its operating conditions to achieve the optimization of operation under different heating demands. Different operating conditions need to be designed according to the actual heating demands, mainly by adjusting the opening degree of the connecting pipe hydraulic butterfly valve 11 to regulate the steam inlet flow rate of the second low-pressure cylinder 10.

[0114] In one embodiment, the high back pressure heating unit 117 includes a high back pressure condenser 12. The first input end (exothermic side inlet) of the high back pressure condenser 12 is connected to the second exhaust steam outlet of the second low-pressure cylinder 10. The second input end (endothermic side inlet) of the high back pressure condenser 12 inputs the return water of the heat network. The first output end of the high back pressure condenser 12 is respectively connected to the second input ends of the first back pressure power generation unit 113 and the second back pressure power generation unit 118 through the heat network circulating water pipeline. The second output end of the high back pressure condenser 12 is connected to the input end of the exhaust steam device 240, and the high back pressure condenser 12 exhausts steam to the exhaust steam device 240.

[0115] In one embodiment, the second back pressure power generation unit 118 includes: a second back pressure steam turbine 13, a second back pressure generator 14, and a second back pressure generator condenser 15. The input end of the second back pressure steam turbine 13 is connected to the first output end of the second intermediate extraction steam supply unit 115, and the output end of the second back pressure steam turbine 13 is connected to the input end of the second back pressure generator 14. The second back pressure steam turbine 13 is used to generate mechanical energy based on the second intermediate extraction steam, and the second back pressure steam turbine 13 can also be used for heating. The output end of the second back pressure generator 14 is connected to the first input end of the second back pressure generator condenser 15. The second back pressure generator 14 exhausts steam to the second back pressure generator condenser 15, and the second back pressure generator 14 is used to generate electricity based on the mechanical energy generated by the second back pressure steam turbine 13.

[0116] In one embodiment, the second input end of the second back-pressure generator condenser 15 is connected to the first output end of the high back-pressure heating unit 117. The output end of the second back-pressure generator condenser 15 is respectively connected to the output end of the first back-pressure power generation unit 113 and the first input end of the second heat network heating unit 119. The second back-pressure generator condenser 15 is used for cooling the exhaust steam of the second back-pressure generator 14 and energy recovery.

[0117] In one embodiment, the second heat network heating unit 119 includes: a second heat network circulating water pump steam turbine 18 and a second heat network heater 17. The input end of the second heat network circulating water pump steam turbine 18 is connected to the second output end of the second extraction steam supply unit 115 in the middle extraction. The output end of the second heat network circulating water pump steam turbine 18 is connected to the second input end of the second heat network heater 17. The second heat network circulating water pump steam turbine 18 is used for driving the second heat network heater 17.

[0118] Among them, the exhaust steam of the second heat network circulating water pump steam turbine 18 can enter the second heat network heater 17 to realize the recovery and utilization of heat, further improving the energy utilization efficiency. The second extraction steam in the middle extraction provides a driving steam source for the second heat network circulating water pump steam turbine 18 and supplies heat to the second heat network heater 17.

[0119] In one embodiment, the first input end of the second heat network heater 17 is connected to the output end of the second back-pressure power generation unit 118. The output end of the second heat network heater 17 outputs heat network supply water. The second heat network heater 17 is used for secondary heating of the heat network return water heated by the high back-pressure heating unit 117 and outputs the heated heat network return water.

[0120] In one embodiment, the cogeneration device 100 for low-pressure cylinder micro-output combined with high back-pressure transformation further includes a heat network circulating water driving unit 120 at the heat supply first station. The input end of the heat network circulating water driving unit 120 is connected to the output ends of the first back-pressure power generation unit 113 and the second back-pressure power generation unit 118 through a heat network circulating water pipeline. The heat network return water heated by the high back-pressure heating unit 117, the condensate water of the first back-pressure generator condenser 6, and the condensate water of the second back-pressure generator condenser 15 converge and flow into the heat network circulating water driving unit 120. The first output end of the heat network circulating water driving unit 120 is connected to the first input end of the first heat network heating unit 114 through a heat network circulating water pipeline. The second output end of the heat network circulating water driving unit 120 is connected to the first input end of the second heat network heating unit 119 through a heat network circulating water pipeline. The heat network circulating water driving unit 120 is used to provide power for the heat network return water circulation to ensure that the heat network return water can circulate in the system according to a preset flow rate.

[0121] In one embodiment, the heat network circulating water driving unit 120 includes a heat network circulating water pump 16. The input end of the heat network circulating water pump 16 is connected through a heat network circulating water pipeline to the output ends of the first back-pressure power generation unit 113 and the second back-pressure power generation unit 118. The heat network return water heated by the high back-pressure heating unit 117, the condensate water of the first back-pressure generator condenser 6, and the condensate water of the second back-pressure generator condenser 15 flow together into the heat network circulating water pump 16 after being combined. The first output end of the heat network circulating water pump 16 is connected through a heat network circulating water pipeline to the first input end of the first heat network heating unit 114, and the second output end of the heat network circulating water pump 16 is connected through a heat network circulating water pipeline to the first input end of the second heat network heating unit 119.

[0122] In one embodiment, the first heat network circulating water pump steam turbine 7 and the second heat network circulating water pump steam turbine 18 can not only effectively drive the first heat network heater 8 and the second heat network heater 17 respectively, but also be applicable to driving the heat network circulating water pump 16, thereby improving the efficiency and economic benefits of the entire heating system. The first heat network circulating water pump steam turbine 7 and the second heat network circulating water pump steam turbine 18 are respectively connected to the heat network circulating water pump 16 (not shown in the figure) through a coupling device to achieve direct drive.

[0123] Please refer to Figure 3 , Figure 3 which is a schematic block diagram of the cogeneration system 200 with low-pressure cylinder micro-output combined with high back-pressure transformation provided by the embodiments of the present application. As Figure 3 shown, the cogeneration system 200 with low-pressure cylinder micro-output combined with high back-pressure transformation includes: a first air-cooled island 210, a second air-cooled island 220, a heat network return water supply device 230, an exhaust steam device 240, a first heat network water supply device 250, a second heat network water supply device 260, and a cogeneration device 100 with low-pressure cylinder micro-output combined with high back-pressure transformation.

[0124] Combined with Figure 2 and Figure 3 , in one embodiment, the first input end of the cogeneration device 100 with low-pressure cylinder micro-output combined with high back-pressure transformation is connected to the output end of the heat network return water supply device 230, and the first output end of the cogeneration device 100 with low-pressure cylinder micro-output combined with high back-pressure transformation is connected to the input end of the first air-cooled island 210. The first air-cooled island 210 is used to reduce the exhaust steam temperature of the first low-pressure cylinder 2 through an air cooling system so that the exhaust steam of the first low-pressure cylinder 2 is condensed into water for recycling. The second output end of the cogeneration device 100 with low-pressure cylinder micro-output combined with high back-pressure transformation is connected to the input end of the second air-cooled island 220, and the second air-cooled island 220 is used to reduce the exhaust steam temperature of the second low-pressure cylinder 10 through an air cooling system so that the exhaust steam of the second low-pressure cylinder 10 is condensed into water for recycling.

[0125] In one embodiment, the third output end of the cogeneration device 100 with low-pressure cylinder micro-output combined with high backpressure retrofit is connected to the input end of the exhaust steam device 240, and the exhaust steam device 240 is used to discharge the exhaust steam of the high backpressure heating unit 117. The fourth output end of the cogeneration device 100 with low-pressure cylinder micro-output combined with high backpressure retrofit is connected to the input end of the first heat network water supply device 250, and the first heat network water supply device 250 is used to provide heat network water supply to users. The fifth output end of the cogeneration device 100 with low-pressure cylinder micro-output combined with high backpressure retrofit is connected to the input end of the second heat network water supply device 260, and the second heat network water supply device 260 is used to provide heat network water supply to users. The cogeneration device 100 with low-pressure cylinder micro-output combined with high backpressure retrofit is used for power generation and heating supply to users.

[0126] The cogeneration device 100 with low-pressure cylinder micro-output combined with high backpressure retrofit provided by the embodiment of the present application couples the high backpressure retrofit and the low-pressure cylinder micro-output technology, uses the high backpressure condenser 12 of the second cogeneration unit Z2 to heat the return water of the heat network, realizes the cascade heating of the high backpressure unit, and the first low-pressure cylinder 2 obtains stronger heating capacity at the cost of sacrificing part of the output power. In addition, the medium-pressure extraction steam of the two cogeneration units is utilized hierarchically, and a set of backpressure generator sets (i.e., backpressure power generation units) are respectively configured. One steam pipeline is respectively led from the medium-pressure extraction steam main pipe to the two backpressure steam turbines, which can increase the power generation power of the cogeneration unit, improve the thermal efficiency of the cogeneration unit, and reduce the use of high-grade heat at a reduced grade.

[0127] The second cogeneration unit Z2 can flexibly switch and operate under three working conditions of pure condensation, extraction condensation, and backpressure. According to different peak shaving and heating demands, its operating conditions can be flexibly adjusted, so as to achieve the operation optimization under different heating demands. Compared with the traditional single cogeneration technology, the flexibility of the cogeneration unit is greatly improved. Under the condition of fully utilizing the waste heat of the cogeneration unit, while improving the heating capacity, the power loss is also reduced, which is more beneficial to improving the thermal efficiency and has considerable energy-saving and economic benefits.

[0128] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0129] In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed or recorded in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0130] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it; although the present application has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the above embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A heat and power cogeneration device with low-pressure cylinder micro-output combined with high back pressure transformation, characterized in that: The device comprises: a first middle row steam extraction and steam supply unit of a first cogeneration unit, a low-pressure cylinder output regulating unit, a first low-pressure cylinder, a first back-pressure power generation unit, a first heat network heating unit, and a first exhaust steam pipeline arranged between a fourth output end of the first middle row steam extraction and steam supply unit and a steam inlet of the first low-pressure cylinder, a second middle row steam extraction and steam supply unit of a second cogeneration unit, an exhaust steam flow regulating unit, a second low-pressure cylinder, a high back-pressure heating unit, a second back-pressure power generation unit, a second heat network heating unit, and a second exhaust steam pipeline arranged between a third output end of the second middle row steam extraction and steam supply unit and a steam inlet of the second low-pressure cylinder; The first output end of the first middle row steam extraction and supply unit is connected to the first input end of the first back pressure power generation unit, the second output end of the first middle row steam extraction and supply unit is connected to the second input end of the first heat network heating unit, the third output end of the first middle row steam extraction and supply unit is connected to the third input end of the first heat network heating unit, the fourth output end of the first middle row steam extraction and supply unit is connected to the first end of the low pressure cylinder output regulating unit, and the first middle row steam extraction and supply unit is used to provide the first middle row steam extraction to the first back pressure power generation unit and the first heat network heating unit; The low-pressure cylinder output regulating unit is arranged on the first exhaust pipe, the second end of the low-pressure cylinder output regulating unit is connected to the steam inlet of the first low-pressure cylinder, the exhaust outlet of the first low-pressure cylinder is connected to the input end of the first air-cooling island, and the low-pressure cylinder output regulating unit is used to reduce the output of the first low-pressure cylinder; The second input end of the first back-pressure power generation unit is connected to the first output end of the high back-pressure heating unit, the output end of the first back-pressure power generation unit is respectively connected to the output end of the second back-pressure power generation unit and the first input end of the first heat network heating unit, and the first back-pressure power generation unit is used to generate electricity and heat based on the first intermediate exhaust steam extraction; The output end of the first heating network heating unit outputs the heating network supply water, and the first heating network heating unit is used to secondary heat the heating network return water that has been preliminarily heated by the high back pressure heating unit based on the first intermediate exhaust steam extraction, and output the heated heating network return water; The first output end of the second middle row extraction steam supply unit is connected to the first input end of the second back pressure power generation unit, the second output end of the second middle row extraction steam supply unit is connected to the second input end of the second heat network heating unit, the third output end of the second middle row extraction steam supply unit is connected to the first end of the exhaust steam flow regulating unit, and the second middle row extraction steam supply unit is used to provide the second middle row extraction steam to the second back pressure power generation unit and the second heat network heating unit; The exhaust steam flow regulating unit is arranged on the second exhaust steam pipeline, the second end of the exhaust steam flow regulating unit is connected to the steam inlet of the second low-pressure cylinder, the first exhaust steam outlet of the second low-pressure cylinder is connected to the input end of the second air-cooling island, and the exhaust steam flow regulating unit is used to regulate the exhaust steam flow input to the second low-pressure cylinder, so that the second cogeneration unit can switch to operate under pure condensation, extraction condensation or back pressure conditions; The first input end of the high back pressure heating unit is connected to the second exhaust steam outlet of the second low pressure cylinder, the second input end of the high back pressure heating unit inputs the return water of the heating network, the second output end of the high back pressure heating unit is connected to the input end of the exhaust steam device, and the high back pressure heating unit is used to preliminarily heat the return water of the heating network based on the exhaust steam of the second low pressure cylinder; The second input end of the second back-pressure power generation unit is connected to the first output end of the high back-pressure heating unit, the output end of the second back-pressure power generation unit is connected to the first input end of the second heat network heating unit, and the second back-pressure power generation unit is used to generate electricity and heat based on the second middle exhaust steam extraction; The output end of the second heating network heating unit outputs the heating network supply water. The second heating network heating unit is used to secondary heat the heating network return water heated by the high back pressure heating unit based on the second intermediate exhaust steam extraction, and output the heated heating network return water.

2. The heat and power cogeneration device with low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The first middle row steam extraction and supply unit comprises: a first intermediate pressure cylinder and a first middle row steam extraction control module; The first end of the first middle row steam extraction control module is respectively connected to the exhaust outlet of the first medium-pressure cylinder and the first end of the low-pressure cylinder output regulating unit, the second end of the first middle row steam extraction control module is connected to the input end of the first back-pressure power generation unit, the third end of the first middle row steam extraction control module is connected to the second end input end of the first heat network heating unit, the fourth end of the first middle row steam extraction control module is connected to the third input end of the first heat network heating unit, and the first middle row steam extraction control module is used to control the first middle row steam extraction.

3. The cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The low-pressure cylinder output regulating unit comprises a double-valve plate heating butterfly valve; The double valve plate heating butterfly valve is arranged on the first exhaust steam pipe, the first end of the double valve plate heating butterfly valve is connected to the fourth output end of the first middle row steam extraction and supply unit, and the second end of the double valve plate heating butterfly valve is connected to the steam inlet of the first low-pressure cylinder.

4. The heat and power cogeneration device with low-pressure cylinder micro-output combined with high back pressure transformation according to claim 2 is characterized in that: The first intermediate exhaust steam extraction control module includes: a first pneumatic check valve, a first hydraulic fast closing regulating valve, a first electric shut-off valve, a first steam supply gate valve, a first steam supply regulating valve, a first main steam supply pipeline arranged between the exhaust outlet of the first intermediate pressure cylinder and the second input end of the first heating network heating unit, a first bypass steam supply pipeline arranged between the second end of the first electric shut-off valve and the input end of the first back pressure power generation unit, and a second bypass steam supply pipeline arranged between the second end of the first electric shut-off valve and the third input end of the first heating network heating unit; The first pneumatic check valve, the first hydraulic fast closing regulating valve and the first electric shut-off valve are sequentially arranged on the first main steam supply pipeline, the first steam supply gate valve is arranged on the first bypass steam supply pipeline, and the first steam supply regulating valve is arranged on the second bypass steam supply pipeline; The first end of the first pneumatic check valve is connected to the first end of the low-pressure cylinder output regulating unit, the second end of the first pneumatic check valve is connected to the first end of the first hydraulic quick-closing regulating valve, the second end of the first hydraulic quick-closing regulating valve is connected to the first end of the first electric shut-off valve, the second end of the first electric shut-off valve, the first end of the first steam supply gate valve and the first end of the first steam supply regulating valve are respectively connected to the second input end of the first heating network heating unit, the second end of the first steam supply gate valve is connected to the input end of the first back pressure power generation unit, and the second end of the first steam supply regulating valve is connected to the third input end of the first heating network heating unit.

5. The cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The first back-pressure power generation unit comprises: a first back-pressure steam turbine, a first back-pressure generator and a first back-pressure generator condenser; The input end of the first back-pressure steam turbine is connected to the first output end of the first middle row steam extraction steam supply unit, the output end of the first back-pressure steam turbine is connected to the input end of the first back-pressure generator, and the first back-pressure steam turbine is used to generate mechanical energy based on the first middle row steam extraction; The output end of the first back-pressure generator is connected to the first input end of the first back-pressure generator condenser, and the first back-pressure generator is used to generate electricity based on the mechanical energy generated by the first back-pressure steam turbine; The second input end of the first back-pressure generator condenser is connected to the first output end of the high back-pressure heating unit, and the output end of the first back-pressure generator condenser is respectively connected to the output end of the second back-pressure power generation unit and the first input end of the first heat network heating unit, and the first back-pressure generator condenser is used for cooling the exhaust steam of the first back-pressure generator and recovering energy.

6. The heat and power cogeneration device with low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The first heating network heating unit comprises: a first heating network circulating water pump small steam turbine and a first heating network heater; The input end of the small steam turbine of the first heat network circulating water pump is connected to the third output end of the first middle row steam extraction and supply unit, and the output end of the small steam turbine of the first heat network circulating water pump is connected to the third input end of the first heat network heater, and the small steam turbine of the first heat network circulating water pump is used to drive the first heat network heater; The first input end of the first heating network heater is connected to the output end of the first back pressure power generation unit, the second input end of the first heating network heater is connected to the second output end of the first middle row steam extraction and supply unit, the output end of the first heating network heater outputs heating network supply water, and the first heating network heater is used to secondary heat the heating network return water heated by the high back pressure heating unit based on the first middle row steam extraction, and output the heated heating network return water.

7. The cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The second middle row extraction steam supply unit comprises: a second intermediate pressure cylinder and a second middle row extraction steam control module; The first end of the second middle exhaust steam extraction control module is respectively connected to the exhaust outlet of the second intermediate pressure cylinder and the first end of the exhaust steam flow regulating unit, the second end of the second middle exhaust steam extraction control module is connected to the input end of the second back pressure power generation unit, the third end of the second middle exhaust steam extraction control module is connected to the second end input end of the second heat network heating unit, and the second middle exhaust steam extraction control module is used to control the second middle exhaust steam extraction.

8. The cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 7 is characterized in that: The second intermediate exhaust steam extraction control module includes: a second pneumatic check valve, a second hydraulic fast closing regulating valve, a second electric shut-off valve, a second steam supply gate valve, a second steam supply regulating valve, a second main steam supply pipeline arranged between the exhaust outlet of the second intermediate pressure cylinder and the second input end of the second heating network heating unit, and a third bypass steam supply pipeline arranged between the second end of the second electric shut-off valve and the input end of the second back pressure power generation unit; The second pneumatic check valve, the second hydraulic fast closing regulating valve, the second electric shut-off valve and the second steam supply regulating valve are sequentially arranged on the second main steam supply pipeline, and the second steam supply gate valve is arranged on the third bypass steam supply pipeline; The second end of the second pneumatic check valve is connected to the first end of the second hydraulic quick-closing regulating valve, the second end of the second hydraulic quick-closing regulating valve is connected to the first end of the second electric shut-off valve, the second end of the second electric shut-off valve and the first end of the second steam supply gate valve are respectively connected to the first end of the second steam supply regulating valve, the second end of the second steam supply gate valve is connected to the input end of the second back pressure power generation unit, and the second end of the second steam supply regulating valve is connected to the second input end of the second heat network heating unit.

9. The cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The exhaust steam flow regulating unit includes a connecting pipe hydraulic butterfly valve; The connecting pipe hydraulic butterfly valve is arranged on the second exhaust steam pipeline, the first end of the connecting pipe hydraulic butterfly valve is connected to the third output end of the second middle row steam extraction and supply unit, and the second end of the connecting pipe hydraulic butterfly valve is connected to the steam inlet of the second low-pressure cylinder.

10. The cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The high back pressure heating unit comprises a high back pressure condenser; The first input end of the high back-pressure condenser is connected to the second exhaust outlet of the second low-pressure cylinder, the second input end of the high back-pressure condenser inputs return water from the heating network, the first output end of the high back-pressure condenser is respectively connected to the second input end of the first back-pressure power generation unit and the second input end of the second back-pressure power generation unit through a circulating water pipeline of the heating network, and the second output end of the high back-pressure condenser is connected to the input end of the exhaust device.

11. The heat and power cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The second back-pressure power generation unit comprises: a second back-pressure steam turbine, a second back-pressure generator and a second back-pressure generator condenser; The input end of the second back-pressure steam turbine is connected to the first output end of the second middle row steam extraction steam supply unit, the output end of the second back-pressure steam turbine is connected to the input end of the second back-pressure generator, and the second back-pressure steam turbine is used to generate mechanical energy based on the second middle row steam extraction; The output end of the second back-pressure generator is connected to the first input end of the second back-pressure generator condenser, and the second back-pressure generator is used to generate electricity based on the mechanical energy generated by the second back-pressure steam turbine; The second input end of the second back-pressure generator condenser is connected to the first output end of the high back-pressure heating unit, and the output end of the second back-pressure generator condenser is respectively connected to the output end of the first back-pressure power generation unit and the first input end of the second heat network heating unit, and the second back-pressure generator condenser is used for cooling the exhaust steam of the second back-pressure generator and energy recovery.

12. The heat and power cogeneration device with low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The second heating network heating unit comprises: a second heating network circulating water pump small steam turbine and a second heating network heater; The input end of the second heating network circulating water pump small steam turbine is connected to the second output end of the second middle row steam extraction and supply unit, the output end of the second heating network circulating water pump small steam turbine is connected to the second input end of the second heating network heater, and the second heating network circulating water pump small steam turbine is used to drive the second heating network heater; The first input end of the second heating network heater is connected to the output end of the first back pressure power generation unit, and the output end of the second heating network heater outputs the heating network supply water. The second heating network heater is used to reheat the heating network return water heated by the high back pressure heating unit and output the heated heating network return water.

13. A heat and power cogeneration device according to any one of claims 1 to 12, characterized in that: The device also includes a heat network circulating water driving unit; The input end of the heating network circulating water driving unit is connected to the output end of the first back-pressure power generation unit and the output end of the second back-pressure power generation unit through the heating network circulating water pipeline, the first output end of the heating network circulating water driving unit is connected to the first input end of the first heating network heating unit through the heating network circulating water pipeline, the second output end of the heating network circulating water driving unit is connected to the first input end of the second heating network heating unit through the heating network circulating water pipeline, and the heating network circulating water driving unit is used to provide power for the heating network return water circulation.

14. The heat and power cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 13 is characterized in that: The heating network circulating water driving unit comprises a heating network circulating water pump; The input end of the heating network circulating water pump is connected to the output end of the first back-pressure power generation unit and the output end of the second back-pressure power generation unit through a heating network circulating water pipeline, the first output end of the heating network circulating water pump is connected to the first input end of the first heating network heating unit through a heating network circulating water pipeline, and the second output end of the heating network circulating water pump is connected to the first input end of the second heating network heating unit through a heating network circulating water pipeline.

15. A cogeneration system with low-pressure cylinder micro-output and high back pressure transformation, characterized in that: The system comprises: a first air-cooling island, a second air-cooling island, a heat network return water supply device, a steam exhaust device, a first heat network water supply device, a second heat network water supply device, and a heat and power cogeneration device with low-pressure cylinder micro-output combined with high back pressure transformation as described in any one of claims 1 to 14; The first input end of the cogeneration device is connected to the output end of the heat network return water supply device, and the first output end of the cogeneration device is connected to the input end of the first air cooling island, and the first air cooling island is used to reduce the exhaust steam temperature of the first low-pressure cylinder so that the exhaust steam of the first low-pressure cylinder is condensed into water; The second output end of the cogeneration device is connected to the input end of the second air-cooling island, and the second air-cooling island is used to reduce the exhaust steam temperature of the second low-pressure cylinder so that the exhaust steam of the second low-pressure cylinder is condensed into water; The third output end of the cogeneration device is connected to the input end of the exhaust device, and the exhaust device is used to exhaust the exhaust steam of the high back pressure heating unit; the fourth output end of the cogeneration device is connected to the input end of the first heat network water supply device, and the first heat network water supply device is used to provide heat network water supply to users; The fifth output end of the cogeneration device is connected to the input end of the second heat network water supply device, the second heat network water supply device is used to provide heat network water supply to users, and the cogeneration device is used to generate electricity and supply heat to users.

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