A high-parameter steam supply system and method for a large-scale combined heat and power unit

Abstract

The present disclosure relates to a large-scale combined heat and power unit high-parameter steam supply system and method, wherein a superheater of a boiler provides high-parameter steam for high-parameter steam load, a steam turbine converts steam from the boiler into low-temperature and low-pressure steam, a condensate unit, a low-pressure feedwater unit and a high-pressure feedwater unit convert the low-temperature and low-pressure steam into condensate water, sequentially heat the condensate water, and obtain boiler feedwater which is sent to the superheater; a control device obtains an actual superheated steam extraction amount of the high-parameter steam, controls an operating state of an adjusting device based on the actual superheated steam extraction amount and an allowable extraction amount limit; the adjusting device is connected with an outlet of the high-pressure feedwater unit, when in the starting state, the adjusting device receives the boiler feedwater from the high-pressure feedwater unit, and converts the received boiler feedwater into supplementary steam which is sent to a reheater. By using the system of the present disclosure, the problem of reheater over-temperature caused by the decrease of reheater inlet steam flow in the existing main steam large extraction technology can be solved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of new energy and energy saving technology, in particular to a large-scale combined heat and power unit high-parameter steam supply system and method. BACKGROUND

[0002] China has put forward higher requirements for optimizing energy structure and clean and efficient use of coal. Among them, the upgrading of coal-fired units is an important means to improve the utilization efficiency of coal, reduce coal consumption and promote clean energy consumption, which is of great significance to the realization of the goal of carbon peak and carbon neutralization.

[0003] The power industry is one of the main industries of coal consumption and is the key industry for national energy saving and emission reduction. According to the requirements of the state, by 2025, the average coal consumption of thermal power in the country will be reduced to below 300 grams of standard coal per kilowatt-hour. In order to achieve the goal of 300g, through the linkage of "energy saving and consumption reduction transformation, heating transformation and flexibility", various thermal power enterprises actively carry out corresponding transformation, especially heating transformation, which has obvious social benefits, significant energy saving and consumption reduction effect, and considerable economic benefits, and is the focus of various thermal power plants.

[0004] In the heating transformation, industrial steam supply transformation is a key direction, especially for units without residential heating in the south, which is the most effective way to reduce unit coal consumption indicators. Conventional industrial steam supply is generally below 4MPa, which can meet the needs through conventional methods such as cold re-supply, middle connection door participation and heating re-supply, connecting pipe extraction and rotating partition. However, for high-parameter steam above 4MPa, the steam supply means is very limited.

[0005] The current common scheme mainly includes main steam supply, one extraction steam supply and air supply valve steam supply, but due to the limitations of initial design and reheater over-temperature, the single machine steam supply capacity is small, and for 600,000-level units, it is generally not more than 100t / h, and for 300,000-level units, it is generally not more than 50t / h. The steam demand of several hundred tons for high-parameter steam users such as chemical industry and petroleum industry is quite different, which limits the scale and range of combined heat and power units. In addition, due to the limitation of current power grid deep peak regulation, the actual high-parameter steam supply capacity of thermal power units is also reduced, which cannot meet the needs of the high-parameter industrial steam supply market, and limits the development of combined heat and power.

[0006] In summary, the steam supply technology in the prior art cannot well solve the reheater over-temperature problem and cannot improve the high-parameter steam extraction capacity, thereby limiting the development of combined heat and power. SUMMARY

[0007] The present disclosure aims to at least partially solve one of the technical problems in the related art. To this end, one object of the present disclosure is to provide a high-parameter steam supply system and method for a large combined heat and power unit, to solve the problem of over-temperature caused by the decrease of re-heater inlet steam flow due to the flow imbalance of the super-heater and re-heater after a large amount of main steam extraction of the large combined heat and power unit in the prior art.

[0008] To achieve the above object, the first aspect of the present disclosure provides a high-parameter steam supply system for a large combined heat and power unit, comprising a steam supply device, an adjusting device and a control device;

[0009] The steam supply device comprises a boiler, a steam turbine, a condensate unit, a low-pressure feedwater unit and a high-pressure feedwater unit, the boiler comprises a super-heater and a re-heater, the super-heater is used to provide high-parameter steam for a high-parameter steam load, the steam turbine is used to convert the received steam from the boiler into low-temperature and low-pressure steam, the condensate unit is used to convert the low-temperature and low-pressure steam into condensate water, the low-pressure feedwater unit is used to heat the condensate water, and the high-pressure feedwater unit is used to heat the heated condensate water to obtain boiler feedwater and send the boiler feedwater to the super-heater;

[0010] The control device is used to obtain an actual super-heated steam extraction amount of the high-parameter steam, control the operating state of the adjusting device based on the actual super-heated steam extraction amount and an allowable extraction amount limit, and the operating state comprises a start state and a stop state;

[0011] The adjusting device is connected with the outlet of the high-pressure feedwater unit, and the adjusting device is used to receive the boiler feedwater from the high-pressure feedwater unit when in the start state, and convert the received boiler feedwater into supplementary steam and send the supplementary steam to the re-heater.

[0012] In one embodiment of the present disclosure, the steam turbine comprises a high-pressure cylinder, the steam supply device further comprises a first inlet steam pipeline and a first outlet steam pipeline, the inlet steam port of the high-pressure cylinder is connected with the outlet steam port of the super-heater through the first inlet steam pipeline, the outlet steam port of the high-pressure cylinder is connected with the inlet steam port of the re-heater through the first outlet steam pipeline, the adjusting device comprises a supplementary steam pipeline connecting the outlet of the high-pressure feedwater unit and the first outlet steam pipeline and a flash module arranged on the supplementary steam pipeline, and the flash module is used to convert the boiler feedwater in the supplementary steam pipeline into supplementary steam.

[0013] In one embodiment of the present disclosure, the adjusting device further comprises a make-up steam flow measuring module arranged on the make-up steam pipeline and a flow control valve, the make-up steam flow measuring module is used to detect the flow of the make-up steam, and the flow control valve is used to control the flow of the boiler feed water; the control device is further used to acquire the flow of the make-up steam, and adjust the opening of the flow control valve based on the flow of the make-up steam and the actual superheated steam extraction amount.

[0014] In one embodiment of the present disclosure, the adjusting device further comprises a first pressure measuring module and a pressure control valve, the first pressure measuring module is used to detect the pressure of the make-up steam, and the pressure control valve is used to control the pressure of the make-up steam, and the steam supply device further comprises a second pressure measuring module, the second pressure measuring module is used to detect the outlet steam pressure of the high-pressure cylinder; the control device is further used to acquire the pressure of the make-up steam and the outlet steam pressure of the high-pressure cylinder, and adjust the opening of the pressure control valve based on the pressure of the make-up steam and the outlet steam pressure of the high-pressure cylinder.

[0015] In one embodiment of the present disclosure, the steam turbine comprises a medium-pressure cylinder, and the steam supply device further comprises a second inlet steam pipeline, the inlet steam port of the medium-pressure cylinder is connected with the outlet steam port of the reheater through the second inlet steam pipeline.

[0016] In one embodiment of the present disclosure, the steam turbine comprises a low-pressure cylinder, and the steam supply device further comprises a third inlet steam pipeline, the inlet steam port of the low-pressure cylinder is connected with the outlet steam port of the medium-pressure cylinder through the third inlet steam pipeline.

[0017] In one embodiment of the present disclosure, the steam supply device further comprises a third pressure measuring module and a medium-low pressure cylinder communication pipe butterfly valve arranged on the third inlet steam pipeline, the third pressure measuring module is used to detect the axial thrust of the steam turbine, and the control device is further used to acquire the axial thrust and adjust the opening of the medium-low pressure cylinder communication pipe butterfly valve based on the axial thrust and an axial thrust limit value.

[0018] To achieve the above object, a large-scale combined heat and power unit high-parameter steam supply method is provided in the second aspect of the present disclosure, which uses the large-scale combined heat and power unit high-parameter steam supply system in the first aspect of the present disclosure to supply steam, comprising:

[0019] The superheater of the boiler is used to provide high-parameter steam for the high-parameter steam load, and the boiler is used to provide steam for the steam turbine;

[0020] The steam turbine is used to convert the steam from the boiler into low-temperature and low-pressure steam;

[0021] The low-temperature and low-pressure steam is converted into condensate water by a condensate unit, the condensate water is heated by a low-pressure feed water unit, and the heated condensate water is reheated by a high-pressure feed water unit to obtain boiler feed water and send the boiler feed water to the superheater;

[0022] An actual superheated steam extraction amount of the high-parameter steam is obtained, and a running state of an adjusting device is controlled based on the actual superheated steam extraction amount and an allowable extraction amount limit value, the running state including a starting state and a closing state.

[0023] When the adjusting device is in the starting state, the adjusting device receives boiler feed water from the high-pressure feed water unit and converts the received boiler feed water into supplementary steam to be sent to a reheater of the boiler.

[0024] In an embodiment of the present disclosure, when the adjusting device is in the starting state, the adjusting device receives boiler feed water from the high-pressure feed water unit and converts the received boiler feed water into supplementary steam to be sent to a reheater of the boiler, including:

[0025] When the adjusting device is in the starting state, the adjusting device receives boiler feed water from the high-pressure feed water unit and converts the received boiler feed water into supplementary steam.

[0026] A flow rate of the supplementary steam is obtained, and an opening degree of a flow control valve is adjusted by a control device based on the flow rate of the supplementary steam and the actual superheated steam extraction amount, so that the flow rate of the supplementary steam meets a first requirement.

[0027] A pressure of the supplementary steam is obtained, and an opening degree of a pressure control valve is adjusted by a control device based on the pressure of the supplementary steam, so that the pressure of the supplementary steam meets a second requirement.

[0028] The supplementary steam meeting the first requirement and the second requirement is sent to the reheater.

[0029] In an embodiment of the present disclosure, an axial thrust of the steam turbine is obtained, and an opening degree of a medium-low pressure cylinder communication pipe butterfly valve is adjusted by a control device based on the axial thrust and an axial thrust limit value, so that the axial thrust meets a third requirement.

[0030] In one or more embodiments of the present disclosure, the steam supply device includes a boiler, a steam turbine, a condensate water unit, a low-pressure feed water unit, and a high-pressure feed water unit, the boiler includes a superheater and a reheater, the superheater provides high-parameter steam for a high-parameter steam load, the steam turbine converts steam from the boiler into low-temperature and low-pressure steam, the condensate water unit is used to convert the low-temperature and low-pressure steam into condensate water, the low-pressure feed water unit is used to heat the condensate water, and the high-pressure feed water unit is used to heat the heated condensate water to obtain boiler feed water and send the boiler feed water to the superheater; the control device obtains an actual superheated steam extraction amount of the high-parameter steam, controls the operating state of the adjusting device based on the actual superheated steam extraction amount and an allowable extraction amount limit, the adjusting device is connected with an outlet of the high-pressure feed water unit, and when the adjusting device is in a starting state, the adjusting device receives the boiler feed water from the high-pressure feed water unit and converts the boiler feed water into supplementary steam to be sent to the reheater. In this case, a certain amount of boiler feed water is taken out from the high-pressure feed water unit to the adjusting device, the boiler feed water from the high-pressure feed water unit is changed into steam by the adjusting device, and the steam is sent to the reheater for appropriate steam supplement, so that the reheater inlet steam flow is increased, and the reheater over-temperature phenomenon is avoided. The problem that the reheater inlet steam flow is reduced to cause the reheater over-temperature due to the imbalance of the flow of the superheater and the reheater after a large amount of steam is extracted from the main steam of a large-scale combined heat and power unit in the prior art is solved.

[0031] Additional aspects and advantages of the present disclosure will be made apparent from the following description, which, guided by the attached drawings, refers to a preferred embodiment thereof. BRIEF DESCRIPTION OF DRAWINGS

[0032] The above and / or additional aspects and advantages of the present disclosure will become apparent and be readily appreciated from the following description, taken in conjunction with the accompanying drawings, in which:

[0033] Figure 1 A block diagram of a high-parameter steam supply system of a large-scale combined heat and power unit provided by an embodiment of the present disclosure;

[0034] Figure 2 A structural schematic diagram of a steam supply device provided by an embodiment of the present disclosure;

[0035] Figure 3 A structural schematic diagram of an adjusting device provided by an embodiment of the present disclosure;

[0036] Figure 4 A structural schematic diagram of a high-parameter steam supply system of a large-scale combined heat and power unit provided by an embodiment of the present disclosure;

[0037] Figure 5 A flowchart of a high-parameter steam supply method of a large-scale combined heat and power unit provided by an embodiment of the present disclosure;

[0038] Figure 6A flow chart of another large-scale combined heat and power unit high-parameter steam supply method provided by the embodiments of the present disclosure is shown in FIG. 1.

[0039] Reference signs:

[0040] 1 - steam supply device; 2 - adjusting device; 3 - control device; 1-1 - boiler; 1-2 - high-pressure cylinder; 1-3 - intermediate-pressure cylinder; 1-4 - low-pressure cylinder; 1-5 - condenser; 1-6 - condensate pump; 1-7 - low-pressure heater; 1-8 - deaerator; 1-9 - feedwater pump; 1-10 - high-pressure heater; 1-11 - intermediate-low-pressure cylinder communication pipe butterfly valve; 1-12 - valve group; 1-13 - steam flow measurement module; A - superheated steam pipeline; B - high-temperature reheated steam pipeline; 2-1 - on-off valve; 2-2 - flow control valve; 2-3 - flash module; 2-4 - make-up steam flow measurement module; 2-5 - first pressure measurement module; 2-6 - pressure control valve; 2-7 - second pressure measurement module. DETAILED DESCRIPTION

[0041] The exemplary embodiments will be described in detail herein with reference to the accompanying drawings. In the following description, unless otherwise indicated, like numbers in the different drawings represent the same or similar elements. The following exemplary embodiments described in the detailed description are not meant to be exhaustive or to be limiting in scope. Rather, they are intended to be illustrative of some aspects of the present disclosure.

[0042] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the different embodiments or examples described in the present specification and the features of the different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0043] In addition, the terms "first", "second", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance or implying the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited. It should also be understood that the term "and / or" used in the present disclosure means and includes any or all possible combinations of one or more associated listed items.

[0044] Embodiments of this disclosure are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this disclosure, and should not be construed as limiting this disclosure.

[0045] This disclosure provides a high-parameter steam supply system and method for large-scale cogeneration units. The main purpose is to solve the problem of overheating caused by the imbalance of superheater and reheater flow rates after a large amount of main steam is extracted from the main steam of large-scale cogeneration units.

[0046] In the first embodiment, Figure 1 This is a block diagram of a high-parameter steam supply system for a large-scale combined heat and power unit, provided as an embodiment of this disclosure. Figure 1 As shown, the high-parameter steam supply system of this large-scale combined heat and power unit includes a steam supply device 1, a regulating device 2, and a control device 3. The steam supply device 1 and the regulating device 2 are respectively connected to the control device 3, and the steam supply device 1 is connected to the regulating device 2.

[0047] In this embodiment, the steam supply device 1 includes a boiler, a steam turbine, a condensate unit, a low-pressure feedwater unit, and a high-pressure feedwater unit. The boiler includes a superheater and a reheater. The superheater is used to provide high-parameter steam for high-parameter steam loads. The steam turbine is used to convert the received steam heat energy from the boiler into useful work and discharge low-temperature, low-pressure steam. The condensate unit is used to convert the low-temperature, low-pressure steam into condensate. The low-pressure feedwater unit is used to heat the condensate. The high-pressure feedwater unit is used to reheat the heated condensate to obtain boiler feedwater and send it to the superheater.

[0048] Figure 2 This is a schematic diagram of the structure of a steam supply device provided in an embodiment of this disclosure.

[0049] Specifically, in some embodiments, such as Figure 2 As shown, the steam supply unit 1 includes a boiler 1-1. The boiler 1-1 is used to generate steam for the steam turbine and high-parameter steam load. The boiler 1-1 includes a superheater and a reheater. The superheater is used to generate superheated steam, and the reheater is used to generate reheated steam. The superheated steam is high-temperature and high-pressure steam, and the reheated steam is steam that has been reheated from the steam discharged from the high-pressure cylinder.

[0050] In some embodiments, such as Figure 2 As shown, the superheater includes a superheated steam pipe A, and the reheater includes a high-temperature reheated steam pipe B. Superheated steam is output from the outlet of superheated steam pipe A (i.e., the steam outlet of the superheater), and reheated steam is output from the outlet of high-temperature reheated steam pipe B (i.e., the steam outlet of the reheater).

[0051] In the present embodiment, the steam turbine is used to convert the heat energy (i.e. steam heat energy) received from the boiler 1-1 into mechanical energy, and output low-temperature and low-pressure steam.

[0052] Specifically, as shown in Figure 2 , the steam turbine includes a high-pressure cylinder 1-2, a medium-pressure cylinder 1-3, and a low-pressure cylinder 1-4. Among them, the boiler 1-1, the high-pressure cylinder 1-2, the medium-pressure cylinder 1-3, and the low-pressure cylinder 1-4 are connected in sequence.

[0053] In some embodiments, the steam supply device 1 further includes a first steam inlet pipeline and a first steam outlet pipeline, the steam inlet of the high-pressure cylinder 1-2 is connected with the steam outlet of the superheater through the first steam inlet pipeline, and the steam outlet of the high-pressure cylinder 1-2 is connected with the steam inlet of the reheater through the first steam outlet pipeline. In this case, the high-pressure cylinder 1-2 receives the superheated steam from the superheater through the first steam inlet pipeline, and the steam output by the high-pressure cylinder 1-2 is sent back to the reheater through the first steam outlet pipeline.

[0054] In some embodiments, the steam supply device 1 further includes a second steam inlet pipeline, the steam inlet of the medium-pressure cylinder 1-3 is connected with the steam outlet of the reheater through the second steam inlet pipeline. In this case, the medium-pressure cylinder 1-3 receives the reheated steam from the reheater through the second steam inlet pipeline.

[0055] In some embodiments, the steam supply device 1 further includes a third steam inlet pipeline, the steam inlet of the low-pressure cylinder 1-4 is connected with the steam outlet of the medium-pressure cylinder 1-3 through the third steam inlet pipeline. In this case, the steam output by the medium-pressure cylinder 1-3 enters the low-pressure cylinder 1-4 through the third steam inlet pipeline.

[0056] In some embodiments, as shown in Figure 2 , the steam supply device 1 includes a medium-low-pressure cylinder communication pipe butterfly valve 1-11 arranged on the third steam inlet pipeline. The medium-low-pressure cylinder communication pipe butterfly valve 1-11 is used to control the pressure of the steam entering the low-pressure cylinder 1-4 to change the axial thrust, specifically, the medium-low-pressure cylinder communication pipe butterfly valve 1-11 receives a thrust adjusting instruction from the control device 3, changes the opening degree of the medium-low-pressure cylinder communication pipe butterfly valve 1-11, thereby controlling the exhaust pressure of the medium-pressure cylinder 1-3, thereby being able to change the axial thrust of the steam turbine, and adjust the axial thrust of the unit within the operating range.

[0057] In some embodiments, the steam supply device 1 further includes a steam delivery branch, the steam delivery branch is connected with the first steam inlet pipeline, and the superheated steam output by the superheater enters the steam turbine through the first steam inlet pipeline, and part of the superheated steam enters the steam delivery branch to be sent to the high-pressure industrial steam supply system (i.e. high-parameter steam load). The part of the superheated steam entering the steam delivery branch can also be referred to as high-parameter steam.

[0058] In some embodiments, the steam supply device 1 further comprises a valve group 1-12 and a steam flow measurement module 1-13 arranged on the steam supply branch. The valve group 1-12 is used to adjust the flow rate and other parameters of the high-parameter steam in the steam supply branch. The steam flow measurement module 1-13 is used to detect the actual superheated steam extraction amount of the high-parameter steam sent to the high-parameter steam load, and send the detected actual superheated steam extraction amount to the control device 3.

[0059] In some embodiments, the steam supply device 1 further comprises a third pressure measurement module for detecting the axial thrust of the steam turbine and sending the detected axial thrust of the steam turbine to the control device 3.

[0060] In the present embodiment, the condensate water unit is used to convert low-temperature and low-pressure steam into condensate water, the low-pressure feed water unit is used to heat the condensate water, and the high-pressure feed water unit is used to reheat the heated condensate water to obtain boiler feed water and send it to the superheater. The inlet of the condensate water unit is connected to the steam turbine, and the outlet of the high-pressure feed water unit is connected to the boiler.

[0061] Specifically, in some embodiments, as shown in Figure 2 The condensate water unit includes a condenser 1-5 and a condensate water pump 1-6, and the low-pressure feed water unit includes a low-pressure heater 1-7 and a deaerator 1-8. The high-pressure feed water unit includes a feed water pump 1-9 and a high-pressure heater 1-10. The condenser 1-5, the condensate water pump 1-6, the low-pressure heater 1-7, the deaerator 1-8, the feed water pump 1-9 and the high-pressure heater 1-10 are connected in sequence by pipelines.

[0062] In some embodiments, the condenser 1-5 is connected to the low-pressure cylinder 1-4, and is used to convert the low-temperature and low-pressure steam output by the low-pressure cylinder 1-4 into condensate water.

[0063] In some embodiments, the condensate water pump 1-6 is used to send the condensate water output by the condenser 1-5 to the low-pressure heater 1-7.

[0064] In some embodiments, the low-pressure heater 1-7 is used to heat the condensate water for feed water treatment to preliminarily increase the temperature of the condensate water.

[0065] In some embodiments, the deaerator 1-8 is used to perform deaeration treatment on the condensate water output by the low-pressure heater 1-7 to obtain boiler feed water.

[0066] In some embodiments, the feed water pump 1-9 is used to send the boiler feed water to the superheater.

[0067] In some embodiments, the high-pressure heater 1-10 is connected to the steam inlet of the superheater. The high-pressure heater 1-10 is used to pressurize and heat the boiler feedwater delivered by the feedwater pump 1-9 so that the boiler feedwater reaching the superheater meets the required temperature and pressure. The high-pressure heater is also called an industrial heater.

[0068] like Figure 2 As shown, the specific connections of the steam supply unit 1 include: the outlet of the superheated steam pipeline A of boiler 1-1 is divided into two paths. The first path is connected to valve group 1-12 (i.e., extraction steam valve group) and steam flow measurement module 1-13 respectively. The second path is connected to the steam inlet of high-pressure cylinder 1-2. The exhaust pipeline of high-pressure cylinder 1-2 (i.e., the first steam outlet pipeline) is connected to the inlet of superheated steam pipeline A of boiler 1-1. The steam inlet of intermediate-pressure cylinder 1-3 is connected to the outlet of high-temperature reheat steam pipeline B of boiler 1-1. The outlet of the exhaust pipeline of intermediate-pressure cylinder 1-3 is connected in sequence to butterfly valve 1-11 of the intermediate-low-pressure cylinder connecting pipe and the steam inlet of low-pressure cylinder 1-4. The outlet of the exhaust pipeline of low-pressure cylinder 4 is connected to the inlet of condenser 1-5. The condensate pipeline at the outlet of condenser 1-5 is connected in sequence to condensate pump 1-6, low-pressure heater 1-7, deaerator 1-8, feedwater pump 1-9 and high-pressure heater 1-10. The outlet feedwater pipe of the high-pressure heater 1-10 is connected to the inlet of the superheated steam pipe A of the boiler 1-1.

[0069] In this embodiment, the regulating device 2 is connected to the outlet of the high-pressure feedwater unit. When the regulating device 2 is in the start-up state, it receives boiler feedwater from the high-pressure feedwater unit and converts the received boiler feedwater into make-up steam to be sent to the reheater.

[0070] Figure 3 This is a schematic diagram of the structure of an adjustment device provided in an embodiment of this disclosure. Figure 4 This is a schematic diagram of the structure of a high-parameter steam supply system for a large-scale combined heat and power unit provided in an embodiment of this disclosure.

[0071] Specifically, in some embodiments, such as Figure 3 and Figure 4 As shown, the regulating device 2 includes a make-up steam pipeline connecting the outlet of the high-pressure feedwater unit and the first steam outlet pipeline, and a switch valve 2-1 installed on the make-up steam pipeline. When the regulating device 2 is in the start-up state, the switch valve 2-1 is open, and a portion of the boiler feedwater output from the high-pressure feedwater unit enters the make-up steam pipeline of the regulating device 2. The boiler feedwater entering the make-up steam pipeline of the regulating device 2 is processed by the regulating device 2 and converted into the required make-up steam. The make-up steam enters the first steam outlet pipeline and enters the reheater together with the steam output from the high-pressure cylinder 1-2.

[0072] In some embodiments, the switching valve 2-1 is turned on or off under the control of the control device 3. If the switching valve 2-1 receives a start command from the control device 3, the switching valve 2-1 is turned on and the regulating device 2 is in the start state. If the switching valve 2-1 receives a stop command from the control device 3, the switching valve 2-1 is turned off and the regulating device 2 is in the off state.

[0073] In some embodiments, such as Figure 3 As shown, the regulating device 2 includes a flow control valve 2-2 installed on the make-up steam pipeline. The flow control valve 2-2 is used to control the flow rate of boiler feedwater entering the make-up steam pipeline of the regulating device 2. If the flow control valve 2-2 receives a shut-off command from the control device 3, the flow control valve 2-2 closes; if the flow control valve 2-2 receives a start command from the control device 3, the flow control valve 2-2 starts; if it receives a flow regulation command from the control device 3, the opening degree of the flow control valve 2-2 is changed.

[0074] In some embodiments, such as Figure 3 As shown, the regulating device 2 includes a flash steam module 2-3 installed on the make-up steam pipeline. The flash steam module 2-3 is used to convert the boiler feedwater in the make-up steam pipeline into make-up steam. Make-up steam refers to the steam obtained from the conversion of boiler feedwater in the make-up steam pipeline. If the flash steam module 2-3 receives a shutdown command from the control device 3, the flash steam module 2-3 will shut down; if it receives a start command from the control device 3, the flash steam module 2-3 will resume operation.

[0075] In some embodiments, such as Figure 3 As shown, the regulating device 2 also includes a steam replenishment flow measurement module 2-4 installed on the steam replenishment pipeline. The steam replenishment flow measurement module 2-4 is used to detect the flow rate of the steam replenishment and send the detected steam replenishment flow rate to the control device 3.

[0076] In some embodiments, such as Figure 3 As shown, the regulating device 2 also includes a first pressure measuring module 2-5, which is used to detect the pressure of the make-up steam and send the detected make-up steam pressure to the control device 3. The detected make-up steam pressure can be the steam pressure at the outlet of the flash evaporation module 2-3.

[0077] In some embodiments, such as Figure 3 As shown, the regulating device 2 also includes a pressure control valve 2-6 installed on the make-up steam pipeline. The pressure control valve is used to control the pressure of the make-up steam. If the pressure control valve 2-6 receives a shut-off command from the control device 3, the pressure control valve 2-6 closes; if the pressure control valve 2-6 receives a start command from the control device 3, the pressure control valve 2-6 starts; if it receives a pressure regulation command from the control device 3, the opening degree of the pressure control valve 2-6 is changed.

[0078] In some embodiments, such as Figure 3 and Figure 4 As shown, the regulating device 2 also includes a second pressure measuring module 2-7, which is used to detect the steam outlet pressure of the high-pressure cylinder 1-2 and send the detected steam outlet pressure of the high-pressure cylinder 1-2 to the control device 3.

[0079] like Figure 4 As shown, the specific connection of the regulating device 2 includes: the outlet feedwater pipe of the high-pressure heater 1-10 is divided into two paths. The first path is connected to the inlet of the superheated steam pipe A of the boiler 1-1. The second path is connected in sequence to the switch valve 2-1, the flow control valve 2-2, the flash evaporation module 2-3, the make-up steam flow measurement module 2-4, and the pressure control valve 2-6. Then, it merges with the exhaust pipe of the high-pressure cylinder 1-2 and is connected to the inlet of the high-temperature reheat steam pipe B of the boiler 1-1.

[0080] In this embodiment, the control device 3 is used to obtain the actual superheated steam extraction rate of high-parameter steam, and based on the actual superheated steam extraction rate and the allowable extraction rate limit, controls the operating state of the regulating device 2, which includes a start-up state and a shutdown state.

[0081] Specifically, the control device 3 acquires the actual superheated steam extraction rate of the high-parameter steam, compares the actual superheated steam extraction rate with the allowable extraction rate limit. If the actual superheated steam extraction rate is less than or equal to the allowable extraction rate limit, the control device 3 outputs a shutdown command to the regulating device 2, controlling the regulating device 2 to be in the closed state. If the actual superheated steam extraction rate is greater than the allowable extraction rate limit, the control device 3 outputs a start command to the regulating device 2, and then acquires parameters such as the flow rate of the make-up steam, the pressure of the make-up steam, and the outlet pressure of the high-pressure cylinder for judgment before outputting the corresponding command.

[0082] In some embodiments, the control device 3 is used to obtain the flow rate of the supplementary steam and adjust the opening of the flow control valve based on the flow rate of the supplementary steam and the actual superheated steam extraction rate. Specifically, the control device 3 first calculates the flow coefficient, multiplies the flow coefficient by the actual superheated steam extraction rate to obtain a first product result, compares the first product result with the flow rate of the supplementary steam, and if the flow rate of the supplementary steam is less than the first product result, the control device 3 outputs a flow adjustment command; if the flow rate of the supplementary steam is equal to the first product result, the supplementary steam meets the first requirement, and the control device 3 does not output a flow adjustment command.

[0083] In some embodiments, the control device 3 is further configured to acquire the pressure of the supplementary steam and the exhaust port pressure of the high-pressure cylinder, and adjust the opening of the pressure control valve based on the pressure of the supplementary steam and the exhaust port pressure of the high-pressure cylinder. Specifically, a pressure correction coefficient is calculated first, the pressure correction coefficient is multiplied by the exhaust port pressure of the high-pressure cylinder to obtain a second product result, the second product result is compared with the pressure of the supplementary steam, if the pressure of the supplementary steam is not equal to the second product result, the control device 3 outputs a pressure adjustment instruction, and if the pressure of the supplementary steam is equal to the second product result, at this time the supplementary steam meets the second requirement, the control device 3 does not output the pressure adjustment instruction.

[0084] In some embodiments, the supplementary steam meeting the first requirement and the second requirement can be steam reaching a pressure close to and higher than the exhaust steam of the high-pressure cylinder 2.

[0085] In some embodiments, the control device 3 is further configured to acquire the axial thrust, and adjust the opening of the low-medium pressure cylinder communication pipe butterfly valve 1-11 based on the axial thrust and the axial thrust limit value. Specifically, the control device 3 compares the axial thrust with the axial thrust limit value, if the axial thrust is greater than the axial thrust limit value, the control device 3 outputs a thrust adjustment instruction, and if the axial thrust is less than or equal to the axial thrust limit value, at this time the supplementary steam meets the third requirement, the control device 3 does not output the thrust adjustment instruction.

[0086] In some embodiments, the opening of each valve in the steam supply system can be expressed by percentage.

[0087] In some embodiments, the specific steam supply of the large-scale combined heat and power unit high-parameter steam supply system includes the following:

[0088] Putting the large-scale combined heat and power unit high-parameter steam supply system (referred to as the steam supply system) into operation;

[0089] Initializing the steam supply system, the initialization process includes calculating the maximum steam extraction limit W0 (i.e. the allowed steam extraction limit, unit t / h), setting the axial thrust limit FZ0 (unit kN), setting the axial thrust limit FZ0 (unit kN), and acquiring the exhaust port pressure P1 of the high-pressure cylinder detected by the second pressure measurement module 2-7 (unit MPa), the actual superheated steam extraction amount W1 detected by the steam flow measurement module 1-13 (unit t / h), the superheated steam enthalpy H1 (unit kJ / kg), the pressure P2 of the supplementary steam detected by the first pressure measurement module 2-5 (unit MPa), the flow rate W2 of the supplementary steam detected by the supplementary steam flow measurement module 2-4 (unit t / h), the enthalpy H2 of the supplementary steam (unit kJ / kg), and the axial thrust FZ of the steam turbine detected by the third pressure measurement module;

[0090] If the actual extraction flow rate of the superheated steam W1 is less than or equal to the limit value of the extraction amount W0, the initialization process is returned to, and a first time difference Δt1 (s) is obtained by timing.

[0091] If the actual extraction flow rate of the superheated steam W1 is greater than the limit value of the extraction amount W0, the following steps are performed.

[0092] (1) The flow coefficient a is calculated, a = f (W1, H1, H2);

[0093] (2) The opening degree V1 of the flow control valve 2-2 is adjusted until W2 = a * W1.

[0094] (3) The pressure correction coefficient b is calculated, b = f (P1).

[0095] (4) The opening degree V2 of the pressure control valve 2-6 is adjusted until P2 = b * P1.

[0096] (5) If FZ is less than or equal to FZ0, a second time difference Δt2 (s) is obtained by timing, and the actual extraction flow rate of the superheated steam W1 and the limit value of the extraction amount W0 are re-judged.

[0097] (6) If FZ is greater than FZ0, the opening degree V3 of the intermediate-low pressure cylinder communication pipe butterfly valve 1-11 is adjusted, and the step (5) is returned.

[0098] In some embodiments, the control logic of the above method is added in the unit control system (i.e. the control device 3), which can achieve the best high-temperature reheat steam supplement effect and maximize the high-parameter steam supply capacity of the unit; the control logic corresponds to a logic module automatic control operation module. In addition, the unit can switch between manual operation and automatic operation optimization during operation.

[0099] In the large-scale combined heat and power unit high-parameter steam supply system of the present disclosure, the steam supply device comprises a boiler, a steam turbine, a condensate unit, a low-pressure feedwater unit and a high-pressure feedwater unit, the boiler comprises a superheater and a reheater, the superheater provides high-parameter steam for high-parameter steam load, the steam turbine converts steam from the boiler into low-temperature and low-pressure steam, the condensate unit is used for converting the low-temperature and low-pressure steam into condensate water, the low-pressure feedwater unit is used for heating the condensate water, and the high-pressure feedwater unit is used for reheating the heated condensate water to obtain boiler feedwater and send the boiler feedwater to the superheater; the control device obtains an actual superheated steam extraction amount of the high-parameter steam, controls the operating state of the adjusting device based on the actual superheated steam extraction amount and an allowable extraction amount limit value; the adjusting device is connected with the outlet of the high-pressure feedwater unit, when the adjusting device is in a starting state, it receives the boiler feedwater from the high-pressure feedwater unit and converts the boiler feedwater into supplementary steam to be sent to the reheater. In this case, a certain amount of boiler feedwater is taken out from the high-pressure feedwater unit to the adjusting device, and the boiler feedwater from the high-pressure feedwater unit is changed into steam by the adjusting device to be sent to the reheater for appropriate supplementary steam, so as to increase the steam flow at the inlet of the reheater and avoid overheating of the reheater. The problem of overheating caused by the decrease of the steam flow at the inlet of the reheater due to the imbalance of the flow of the superheater and the reheater after a large amount of extraction of the main steam in the prior art is solved. Specifically, when the extraction of the steam output by the superheater exceeds the allowable limit value, in order to avoid overheating, a high-temperature reheated steam supplementary device (i.e. the adjusting device) is added to take out a certain amount of high-temperature feedwater from the boiler feedwater, to obtain wet steam with appropriate pressure (i.e. to meet the first requirement and the second requirement) through flash evaporation and pressurization, and to supplement the wet steam to the exhaust pipe of the high-pressure cylinder, so that the inlet of the reheater is appropriately supplemented with steam, the flow of the reheater is increased due to the large extraction of the steam output by the superheater, the overheating of the reheater is avoided, the auxiliary operation adjustment is controlled, and other parameters such as the axial thrust of the unit are within the operating range, so that the extraction capacity of the main steam can be greatly improved, especially the extraction capacity of the industrial steam above 4MPa can be improved, and the heat supply range and the operation flexibility of the combined heat and power unit are expanded. In addition, the purpose of increasing the extraction and supply capacity of the main steam (i.e. the superheated steam output by the superheater), improving the high-parameter steam supply capacity of the combined heat and power unit, improving the heat supply capacity, range and economy of the unit, and effectively alleviating the problem of overheating caused by the decrease of the steam flow at the inlet of the reheater due to the imbalance of the flow of the superheater and the reheater after a large amount of extraction of the main steam of the large-scale combined heat and power unit is achieved. In addition, the steam supply system of the present disclosure has simple structure and low reconstruction investment, and only a small range of reconstruction is needed to significantly improve the high-parameter industrial steam supply capacity, and the system of the present disclosure has flexible operation, and the high-temperature reheated steam supplementary device can be put into operation at any time according to the extraction amount of the main steam.

[0100] The following is an embodiment of the method of the present disclosure. For details not disclosed in the embodiment of the method of the present disclosure, refer to the embodiment of the system of the present disclosure. The embodiment of the method of the present disclosure proposes a large-scale combined heat and power unit high-parameter steam supply method. The large-scale combined heat and power unit high-parameter steam supply method uses the large-scale combined heat and power unit high-parameter steam supply system of the above-mentioned system embodiment to supply steam.

[0101] Figure 5 The flow chart of a large-scale combined heat and power unit high-parameter steam supply method provided by the embodiment of the present disclosure.

[0102] As shown in Figure 5 , the large-scale combined heat and power unit high-parameter steam supply method comprises:

[0103] S101, using the superheater of the boiler to provide high-parameter steam for the high-parameter steam load, and using the boiler to provide steam for the steam turbine;

[0104] S102, using the steam turbine to convert the steam from the boiler into low-temperature and low-pressure steam;

[0105] S103, using the condensate unit to convert the low-temperature and low-pressure steam into condensate water, using the low-pressure feedwater unit to heat the condensate water, and using the high-pressure feedwater unit to reheat the heated condensate water to obtain boiler feedwater and send it to the superheater;

[0106] S104, obtaining the actual superheated steam extraction amount of the high-parameter steam, and based on the actual superheated steam extraction amount and the allowable extraction amount limit, controlling the operating state of the adjusting device, the operating state including the start state and the shutdown state;

[0107] S105, when the adjusting device is in the start state, the adjusting device receives the boiler feedwater from the high-pressure feedwater unit, and converts the received boiler feedwater into supplementary steam and sends it to the reheater of the boiler.

[0108] Optionally, in step S105, when the adjusting device is in the start state, the adjusting device receives the boiler feedwater from the high-pressure feedwater unit, and converts the received boiler feedwater into supplementary steam and sends it to the reheater of the boiler, comprising: when the adjusting device is in the start state, the adjusting device receives the boiler feedwater from the high-pressure feedwater unit, and converts the received boiler feedwater into supplementary steam; obtaining the flow rate of the supplementary steam, the control device adjusting the opening of the flow control valve based on the flow rate of the supplementary steam and the actual superheated steam extraction amount, so that the flow rate of the supplementary steam meets the first requirement; obtaining the pressure of the supplementary steam, the control device adjusting the opening of the pressure control valve based on the pressure of the supplementary steam, so that the pressure of the supplementary steam meets the second requirement; and sending the supplementary steam meeting the first requirement and the second requirement to the reheater.

[0109] Optionally, the large-scale combined heat and power unit high-parameter steam supply method further comprises: obtaining the axial thrust of the steam turbine, and the control device 3 adjusts the opening of the intermediate-low pressure cylinder communication pipe butterfly valve 1-11 based on the axial thrust and the axial thrust limit value, so that the axial thrust meets the third requirement.

[0110] Figure 6 Another flowchart of a large-scale combined heat and power unit high-parameter steam supply method provided by the embodiments of the present disclosure is shown in FIG. 6. Figure 6 The large-scale combined heat and power unit high-parameter steam supply method shown in FIG. 6 comprises:

[0111] putting a large-scale combined heat and power unit high-parameter steam supply system (hereinafter referred to as a steam supply system) into operation;

[0112] performing initialization processing on the steam supply system, the initialization processing including calculating a maximum steam extraction limit value W0 (i.e., an allowed steam extraction limit value), setting an axial thrust limit value FZ0, obtaining the outlet steam pressure P1 of the high-pressure cylinder detected by a second pressure measurement module, the actual superheated steam extraction amount W1, the superheated steam enthalpy H1 (unit: kJ / kg) detected by a steam flow measurement module, the pressure P2 of the supplementary steam detected by a first pressure measurement module, the flow rate W2 of the supplementary steam detected by a supplementary steam flow measurement module, the enthalpy H2 (unit: kJ / kg) of the supplementary steam, and the axial thrust FZ of the steam turbine detected by a third pressure measurement module;

[0113] judging the actual superheated steam extraction flow rate W1 and the allowed steam extraction limit value W0, and if the actual superheated steam extraction flow rate W1 <= the allowed steam extraction limit value W0, returning to the initialization processing and obtaining a first time difference Δt1 by timing;

[0114] if the actual superheated steam extraction flow rate W1 > the allowed steam extraction limit value W0, the following steps are performed;

[0115] (a) calculating a flow rate coefficient a, a = f(W1, H1, H2);

[0116] (b) adjusting the opening V1 of the flow control valve;

[0117] (c) if W2 < a*W1 (or W2 ≠ a*W1), returning to the previous step (b);

[0118] (d) if W2 = a*W1, calculating a pressure correction coefficient b, b = f(P1);

[0119] (e) adjusting the opening V2 of the pressure control valve;

[0120] (f) if P2 ≠ b*P1, returning to the previous step (e);

[0121] (g) if P2 = b*P1.

[0122] (h) If FZ<=FZ0, the second time difference Δt2 is obtained by timing, and the actual superheated steam extraction flow rate W1 and the allowable extraction flow rate limit W0 are returned to be re-judged;

[0123] (i) If FZ>FZ0, the opening V3 of the medium-low pressure cylinder communication pipe butterfly valve is adjusted, and the step (h) is returned;

[0124] For details, please refer to the related description in the above system embodiment, which will not be repeated here.

[0125] It should be noted that the foregoing explanation and description of the embodiment of the large-scale combined heat and power unit high-parameter steam supply system also applies to the method of the large-scale combined heat and power unit high-parameter steam supply system, which will not be repeated here.

[0126] The above-mentioned sequence number of the embodiments of the present disclosure is only for description, and does not represent the advantages and disadvantages of the embodiments.

[0127] In the large-scale combined heat and power unit high-parameter steam supply method of the present disclosure, the superheater of the boiler is used to supply high-parameter steam to the high-parameter steam load, and the boiler is used to supply steam to the steam turbine; the steam turbine is used to convert the steam from the boiler into low-temperature and low-pressure steam; the condensate unit is used to convert the low-temperature and low-pressure steam into condensate water, the low-pressure feed water unit is used to heat the condensate water, and the high-pressure feed water unit is used to heat the condensate water again to obtain the boiler feed water and send it to the superheater; the actual superheated steam extraction amount of the high-parameter steam is obtained, and based on the actual superheated steam extraction amount and the allowable extraction amount limit, the operating state of the adjusting device is controlled, including the start state and the shutdown state; when the adjusting device is in the start state, the adjusting device receives the boiler feed water from the high-pressure feed water unit and converts the received boiler feed water into steam to be supplied to the reheater of the boiler. In this case, a certain amount of boiler feed water is taken out from the high-pressure feed water unit to the adjusting device, and the boiler feed water from the high-pressure feed water unit is changed into steam by the adjusting device to be supplied to the reheater for appropriate steam supplement, increasing the steam flow at the inlet of the reheater and avoiding overheating of the reheater. The problem of reducing the steam flow at the inlet of the reheater and causing overheating after a large amount of steam is extracted from the main steam of the large-scale combined heat and power unit in the prior art is solved. Specifically, when the steam output by the superheater is extracted by a large amount of steam exceeding the allowable limit, in order to avoid overheating, a high-temperature reheated steam supplement device (i.e. adjusting device) is added to take out a certain amount of high-temperature feed water from the boiler feed water, and through flash evaporation and pressurization, wet steam with appropriate pressure (i.e. meeting the first requirement and the second requirement) is obtained to be supplemented to the exhaust pipe of the high-pressure cylinder, so that the inlet of the reheater is appropriately supplemented, the flow of the reheater is reduced after a large amount of steam is extracted from the superheater, the overheating of the reheater is avoided, the auxiliary operation adjustment is controlled, and other parameters such as the axial thrust of the unit are within the operating range, so that the steam extraction capacity of the main steam can be greatly improved, especially the steam supply capacity of industrial steam above 4MPa is improved, and the heat supply range and operation flexibility of the combined heat and power unit are expanded. In addition, it can also achieve the purpose of increasing the steam extraction and supply capacity of the main steam (i.e. superheated steam output by the superheater), improving the high-parameter steam supply capacity of the combined heat and power unit, improving the heat supply capacity, range and economy of the unit, and effectively solving the problem of reducing the steam flow at the inlet of the reheater and causing overheating after a large amount of steam is extracted from the main steam of the large-scale combined heat and power unit.

[0128] It should be understood that the various forms of flow shown above can be reordered, added or deleted steps. For example, each step described in the present disclosure can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved, and the present disclosure is not limited herein.

[0129] The above detailed description does not limit the scope of the disclosure. Various modifications, combinations, sub-combinations and alternatives can be made to the detailed description. Any modification, equivalent replacement and improvement etc. made within the spirit and principle of the disclosure shall be included in the scope of the disclosure.

Claims

1. A high-parameter steam supply system for a large combined heat and power unit, characterized in that, The steam supply device, the adjusting device and the control device are included; The steam supply device includes a boiler, a steam turbine, a condensate water unit, a low-pressure feed water unit and a high-pressure feed water unit, the boiler includes a superheater and a reheater, the superheater is used to provide high-parameter steam for a high-parameter steam load, the steam turbine is used to convert the steam received from the boiler into low-temperature and low-pressure steam, the condensate water unit is used to convert the low-temperature and low-pressure steam into condensate water, the low-pressure feed water unit is used to heat the condensate water, and the high-pressure feed water unit is used to heat the condensate water to obtain boiler feed water and send the boiler feed water to the superheater; The control device is used to obtain an actual superheated steam extraction amount of the high-parameter steam, control an operating state of the adjusting device based on the actual superheated steam extraction amount and an allowable extraction amount limit, and the operating state includes a start state and a stop state. The adjusting device is connected with an outlet of the high-pressure feed water unit, and the adjusting device is used to receive the boiler feed water from the high-pressure feed water unit when being in the start state and convert the received boiler feed water into supplementary steam to be sent to the reheater. The steam turbine includes a high-pressure cylinder, the steam supply device further includes a first inlet steam pipeline and a first outlet steam pipeline, an inlet of the high-pressure cylinder is connected with an outlet of the superheater through the first inlet steam pipeline, and an outlet of the high-pressure cylinder is connected with an inlet of the reheater through the first outlet steam pipeline. The adjusting device further includes a supplementary steam flow measurement module and a flow control valve arranged on the supplementary steam pipeline, the supplementary steam flow measurement module is used to detect a flow of the supplementary steam, and the flow control valve is used to control a flow of the boiler feed water. The adjusting device further includes a first pressure measurement module and a pressure control valve, the first pressure measurement module is used to detect a pressure of the supplementary steam, and the pressure control valve is used to control the pressure of the supplementary steam.

2. The high parameter steam supply system for a large combined heat and power unit according to claim 1, wherein The steam turbine includes a medium-pressure cylinder, and the steam supply device further includes a second inlet steam pipeline, an inlet of the medium-pressure cylinder is connected with an outlet of the reheater through the second inlet steam pipeline.

3. The high parameter steam supply system for a large combined heat and power unit according to claim 2, wherein The steam turbine includes a low-pressure cylinder, and the steam supply device further includes a third inlet steam pipeline, an inlet of the low-pressure cylinder is connected with an outlet of the medium-pressure cylinder through the third inlet steam pipeline.

4. The high parameter steam supply system for a large combined heat and power unit according to claim 3, wherein The steam supply device further comprises a third pressure measuring module and a medium-low pressure cylinder communication pipe butterfly valve arranged on the third steam inlet pipeline, the third pressure measuring module is used to detect an axial thrust of the steam turbine, and the control device is further used to acquire the axial thrust, and adjust an opening degree of the medium-low pressure cylinder communication pipe butterfly valve based on the axial thrust and an axial thrust limit value.

5. A method for supplying high-parameter steam in a large-scale combined heat and power plant, characterized by, The large-scale combined heat and power unit high-parameter steam supply method adopts the large-scale combined heat and power unit high-parameter steam supply system as claimed in any one of claims 1-4 to supply steam, which comprises: The superheater of the boiler is used to provide high-parameter steam for a high-parameter steam load, and the boiler is used to provide steam for the steam turbine; The steam turbine is used to convert the steam from the boiler into low-temperature and low-pressure steam; The condensate unit is used to convert the low-temperature and low-pressure steam into condensate water, the low-pressure feedwater unit is used to heat the condensate water, and the high-pressure feedwater unit is used to reheat the heated condensate water to obtain boiler feedwater and send the boiler feedwater to the superheater; An actual superheated steam extraction amount of the high-parameter steam is acquired, and the operating state of the adjusting device is controlled based on the actual superheated steam extraction amount and an allowable extraction amount limit value, the operating state comprising a start-up state and a shutdown state; When the adjusting device is in the start-up state, the adjusting device receives boiler feedwater from the high-pressure feedwater unit and converts the received boiler feedwater into supplementary steam to be sent to the reheater of the boiler.

6. The method for high parameter steam supply of a large combined heat and power unit according to claim 5, wherein When the adjusting device is in the start-up state, the adjusting device receives boiler feedwater from the high-pressure feedwater unit and converts the received boiler feedwater into supplementary steam to be sent to the reheater of the boiler, comprising: When the adjusting device is in the start-up state, the adjusting device receives boiler feedwater from the high-pressure feedwater unit and converts the received boiler feedwater into supplementary steam; The flow of the supplementary steam is acquired, and the control device adjusts the opening degree of the flow control valve based on the flow of the supplementary steam and the actual superheated steam extraction amount, so that the flow of the supplementary steam meets a first requirement; The pressure of the supplementary steam is acquired, and the control device adjusts the opening degree of the pressure control valve based on the pressure of the supplementary steam, so that the pressure of the supplementary steam meets a second requirement; The supplementary steam meeting the first requirement and the second requirement is sent to the reheater.

7. The method of Claim 6, wherein Further comprising: The axial thrust of the steam turbine is acquired, and the control device adjusts the opening degree of the medium-low pressure cylinder communication pipe butterfly valve based on the axial thrust and an axial thrust limit value, so that the axial thrust meets a third requirement.

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